Integrative Nanomedicine: Treating Cancer With Nanoscale Natural Products

Iris R. Bell, MD, PhD, Barbara Sarter, PhD, APRN, FNP-C, Mary Koithan, PhD, RN, Prasanta Banerji, FMIH, Pratip Banerji, MD(Hom), Shamini Jain, PhD, and John Ives, PhD

Iris R. Bell, Department of Family and Community Medicine, The University of Arizona College of Medicine, Tucson (Dr Bell), United States; College of Nursing, The University of Arizona (Dr Bell), United States;

Contributor Information.

Corresponding author.

Email: [email protected]

Abstract

摘要

SINOPSIS

INTRODUCTION

The purpose of this article is to provide an overview of natural product nanomedicine for cancer treatment as a foundation for understanding the more than 200-years-old complementary and alternative medicine (CAM) system of homeopathy. Historically, various homeopaths have reported successful treatment of patients with cancers using natural product–derived medicines.^1–4 Main topics addressed here are (1) the rationale for using nanoscale forms of natural products in cancer treatment; (2) the evidence for homeopathic medicines as nanoparticle-based natural products; (3) data on studies of homeopathy in cancer treatment; and (4) the Banerji Protocols as a promising clinical approach to cancer using homeopathic remedies, with parallels to research on modern manufactured nanoparticles.

Finding safer and more effective treatments for specific cancers remains a significant challenge for integrative clinicians and researchers worldwide. One emerging strategy is the use of nanostructured forms of drugs, vaccines, herbs, and nutraceutical agents in cancer treatment.^5–10 At the nanoscale range, the source material is typically in the ultrafine particle size range of 1 to 100 nanometers (nm) along at least one side, although some consider nanoforms to include particle sizes up to 1000 nanometers (see Table 1 for definitions of common terms in nanoparticle manufacturing).

Poorly soluble drugs or natural source materials pose practical challenges for administration and effective treatment. In such situations, preparing a medicine or natural product in nano form confers multiple advantages over conventional bulk form drugs.^15,16 These advantages include enhanced bioavailability, adsorptive capacity, and intracellular accessibility.^17,18 The smaller nanoparticles can cross cell membranes readily, including thosein the skin and even the blood-brain barrier. Biological targeting with modern nanomedicines is increasingly precise, including ability to foster specific uptake into malignant cells, stop proliferation, and increase apoptosis with less damage to healthy cells.^19–21

Nanoparticles also can acquire atom-like properties and high surface charge because of their small sizes and large surface area to volume ratios. The altered nanoparticle properties include increased chemical and biological reactivity, electromagnetic, optical, thermal, and quantum effects.²² In turn, the unique properties of nanomedicines typically reduce required doses by orders of magnitude and improve side effect profiles.^18,23–26 Minor variations in surface properties can enhance nanoparticle uptake, especially into cancer cells, eg, conjugation with the disaccharide sugar lactose.^27,28 Surface adsorption of sugars also may enhance immune system responsivity to antigen delivered in vaccines by nanocarriers such as calcium phosphate.²⁹

Nanoparticles under study as diagnostic tools, drug and vaccine delivery vehicles, and biological agents in their own right include

• various metals (eg, silver, gold);

• metal salts (eg, calcium phosphate, magnesium phosphate)^30–32;

• Semiconductors (eg, silicon and its dioxide silica)^33–35;

• lipid- or polysaccharide-based carriers (eg, Poly(lactideco-glycolic acid) [PLGA] or chitosan)^36,37; and

• exosomes.³⁸

Exosomes are nanosized endogenous vesicles from endosomes released by a variety of cells containing proteins, siRNA, and lipids with capabilities for systemic biological signaling.^6,39–43 Certain exogenous nanoparticles can also trigger exosome release and a cascade of systemic stress-related or pro-apoptotic signaling in the immune and inflammatory pathways as well.^42–46 In the immune system, mature dendritic cells pulsed with exosomes can stimulate antitumor activity.⁴⁷ Exosomes derived from malignant tumor cells are also used as experimental cancer treatment vaccines.⁶

NANOSCALE FORMS OF NATURAL PRODUCTS FOR CANCER TREATMENT

One limitation in moving from bench to bedside with nanoparticle diagnostic and therapeutic approaches in mainstream medicine has been concern about the potential toxicity of nanomaterials. Some nanoparticles are especially likely to accumulate in bodily tissues. For instance, unmodified silver or copper nanoparticles can exhibit toxicity risks.⁴⁸ Because of their high adsorptive ability and large surface areas, nanoparticles can also retain trace amounts of any toxic solvents, polymer chemicals, botanical agents, or trace metal dopants used in manufacturing.⁴⁹ Surface modifications of nanoparticles can create agents with very different chemical and/or biological properties from the “same” nanoparticles with unmodified surfaces.^28,50,51

An offshoot of this concern has been a shift toward “green manufacturing” methods. For instance, nanotechnologists use natural products such as botanical or herbal agents or other types of living organisms to biosynthesize gold or silver nanoparticles.^9,52,53 Then trace amounts of the more benign plant material remain adsorbed to the outer nanoparticle surfaces, thereby modifying the nanoparticle sizes and biological effects.⁹ Manufacturing procedures that attach a benign sugar such as lactose to the surfaces of silver nanoparticles can also markedly enhance nanoparticle uptake into malignant, but not healthy cells.²⁸ Plant extracts, DNA, and proteins also guide bottom-up manufacturing via self-assembly of silica precursors into crystalline silica nanostructures^54,55 that can resist drying in some preparations.⁵⁶

In addition, researchers make nano-encapsulations of certain natural, less soluble products from herbs or nutraceuticals. Such nanoforms can overcome gastrointestinal uptake and cellular accessibility problems of their respective bulk forms in vivo.¹⁶ Thus, nanoparticle forms of antioxidants with antiinflamma-tory and antiproliferative properties have markedly enhanced their potential utility for cancer therapy compared with their bulk forms. Examples include nano-forms of curcumin,^37,57–60 quercetin,^5,61,62 and coenzyme Q₁₀.⁶³ PLGA nano-encapsulated herbal extracts of Gelsemium sempervirens also acquire improved anticancer effects.^64,65 Overall, nanoscale forms of natural products add a clinically valuable method for delivering less toxic or nontoxic treatments to people with cancers in which the currently available mainstream approaches are less effective, prone to drug resistance, and/or highly toxic. Given acceptable treatment efficacy, lower toxicity can translate into better patient outcomes.

HOMEOPATHIC REMEDIES AS NANOMEDICINES

Homeopathy is a more than 200-years-old system of alternative medicine developed by the German physician-chemist Samuel Hahnemann, MD. This type of healthcare is used widely around the world. Homeopathy is especially popular in India, the United Kingdom, Germany, France, Belgium, and several Latin American nations. Homeopathic medicines derive from natural mineral, plant, and animal sources, sometimes including diseased tissues (ie, nosodes such as Carcinosin, homeopathically prepared breast cancer tumor).⁶⁶

Unlike in conventional healthcare, the classical homeopathic diagnosis (ie, remedy selection) depends on describing the total clinical pattern of biopsychosocial symptoms. Homeopathically relevant symptoms include adaptive behaviors of the individual person as an indivisible complex system. Classical remedy prescriptions then involve matching the patient’s complete picture with the previously documented ability of a specific single remedy to cause the same pattern in healthy persons. Thus, by definition, homeopathic treatment relies on both (1) individual salience and (2) state dependency in the host to elicit beneficial rather than adverse effects. Remedy dosing typically involves pulsed or intermittent administration at lower doses and lower frequency than used in conventional bulk drug treatment.⁶⁶

A recent development in integrative medicine research is the discovery of persistent nanoparticles of source materials (eg, metals, plants) in homeopathic medicines, sometimes referred to as “remedies” (Figure 1).^67–69 Different homeopathic plant remedy tinctures can also biosynthesize silver nanoparticles, with the resultant nanoparticles. The homeopathic plant-modified silver nanoparticles vary slightly in size and demonstrate somewhat different biological effects against a melanoma cancer cell line in vitro as a function of the plant source material.⁹ In the latter study, the plant-made variants of silver nanoparticles exhibited anticancer effects involving both cell cycle arrest and apoptosis.

Only recently, some homeopaths and nanoscientists recognized the extensive overlaps between green manufacturing of modern nanoparticles and traditional homeopathic manufacturing methods.^9,68,70 Homeopathic manufacturing standards derive from the empirical techniques originally developed by Hahnemann in the 19th century.⁷¹ The essential process of making homeopathic medicines includes⁷²

• natural remedy source materials (plant, mineral, animal, disease tissue sources);

• preparation of ethanolic extracts or tinctures;

• extensive grinding of source materials in lactose; and

• serial dilutions and repeated succussions (agitation) in ethanol-water diluent within glass containers.

Homeopathic manufacturing procedures involve preparation of an ethanol-based extract (plants, disease tissue) and/or trituration (grinding or milling) in lactose over a long period of time for insoluble materials. The ground or milled remedy in lactose is then serially diluted, first in dry lactose for the first few steps and then in ethanol-water diluent in glass containers over multiple subsequent steps. The dilution ratios are typically 1/10 (X or D potencies) or 1/100 (C potencies), followed by vigorous agitation of the solution. Manual manufacturing methods involve 10-100 vigorous succussions per dilution step (agitation in solution by pounding the glass container against a hard surface).⁶⁴

From the dilution process per se, skeptics have long assumed that homeopathic medicines could not plausibly contain any residual molecules of the source material, at potencies with bulk dilutions past 24X or 12C (ie, diluted past the cut-off for Avogadro’s number of molecules). They have generally overlooked the potential role of the other steps in the manufacturing process for generating bioactive agents. Debates over the validity of homeopathy center on this primary dilution argument.^73–77

However, new data indicate that while the specific manufacturing methods for classically prepared remedies probably remove the bulk source materials early in the process of serial dilutions, they leave a layer of detectable source nanoparticles across all dilutions. The data include remedy potencies diluted past Avogadro’s number for bulk materials (Figure 2).⁶⁷ Chikramane et al showed heterogenous accumulation of nanoparticles in a top layer as a result of the creation and movement in solution of bubbles and nanobubbles during succussions. The latter group also proposed that the lactose can serve as a capping agent for nanoparticle growth during trituration67 as well as a vehicle for delivering nanoparticles.^78,79

The specific alcohol itself (ie, ethanol) and its concentration also can modify the properties of nanoparticles made in liquid solutions.^80–82 Agitating a solution of nanoparticles can also help disperse any spontaneous agglomerations of larger clusters into smaller particles.^83,84 Thus, nanoparticles of the source material are found from the lowest to the highest homeopathic potencies across all dilutions. Dilution appears to remove bulk forms but not nanoscale forms of source material.

Furthermore, the succussion process generates readily measurable amounts of silicon, silica (silicon dioxide), and its precursors from the glass walls of the container.^64,69,85,86 Studies on different glassware containing succussed homeopathic remedies, agitated non-homeopathic liquid solutions, and succussed control solutions all demonstrate the variable release of biologically active silica and related chemicals into solution.^69,85,87 Numerous studies show that silicon and silica nanoparticles and crystals can adsorb or attach to source nanoparticles as drug delivery vehicles,^87,88 and/or nonspecifically amplify their biological effects, especially those in the immune system.^45,88,90 Certain forms of porous nanosilicon possess relatively low toxicity and biodegradability in medical applications, including sensitizing the photo-dynamic killing of cancer cells.⁹¹ Very small silicon nanoparticles (quantum dots), depending on their dopant materials, can also generate unique optical effects and transport electric charges: eg, in solar cells.^92,93

Notably, as with silver, plant tinctures can also biosynthesize nanocrystals of silica from its precursors.⁵⁵ Therefore, in addition to the remedy source nanoparticles, the nanosilica and silica crystals from agitation of liquid solutions within glassware likely provide an additional remedy-modified delivery vehicle and nonspecific amplifier of biological effects related to the specific remedy source.^70,94 The documented variability in release of silicon, silica, and its precursors from different types of glassware⁸⁷ could contribute to the well-known variability reported in both basic science and clinical trial studies of homeopathically-prepared medicines.^95,96 From a nanotechnology perspective,^{15,82,84,97,98} methodological variations in homeopathic source materials, grinding procedures, dilutions, succussion procedures, pH, temperature, and ethanol concentrations during remedy preparation would also affect the sizes, shapes, amounts, and properties of the final homeopathic medicines. Even aging during storage can significantly change the properties of both nanoparticles^99–101 and homeopathic remedies.¹⁰²

What would the presence of nanosilica add to natural product cancer treatment? Several nonhomeopathic studies of the effects of a traditional Middle Eastern animal venom–derived treatment on cancer cells begin to answer that question. The addition of modern manufactured silica nanoparticles to a snake venom–derived medicine significantly enhanced the apoptotic and growth arrest effects of the treatment on breast cancer cells (Figure 3).¹⁰³ The same type of combination treatment (snake venom with silica nanoparticles) also improved anticancer effects against malignant myeloma cells¹⁰⁴ and human prostate cancer cells.¹⁰⁵ Like certain types of nanoparticles,^106–108 some homeopathic remedies with antineoplastic properties exhibit the ability to attack cancer cells while leaving healthy cells intact.^109,110

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Figure 3

Silica nanoparticles amplify apoptotic effects of biologically active natural agent. Data from five different experiments are expressed as the mean percentage of apoptotic cells ± SEM for the control (open bars), NP-treated (gray bars), WEV-treated (closed black bars), and WEV+NP–treated (hatched bars). *P < .05, WEV-treated vs NP; #P < .05, WEV+NP-treated vs NP; +P < .05, WEV+NP-treated vs WEV-treated cells. WEV = venom of Walterinnesia aegyptia snake; NP = silica nanoparticles. MDA-MB-231 and MCF-7 are human breast cancer cells; MCF-10 are normal breast epithelial cells. Reprinted with permission from publisher S. Karger AG, Basel, from reference.¹⁰³

Most nanomedicine applications of natural products are still in developmental or early clinical trial phases of study.^5,111 However, with the discovery of nanoparticles in homeopathic remedies, both homeopathic manufacturers and modern nanomedicine practice stand to learn from each other. The overall goal would be to improve research and clinical care of people with cancer using less toxic naturally-based interventions.

What nanoscience brings to homeopathy is modern technological methods. Nanomedicine research insights into nanoparticle characterization and how nanoparticles interact with living systems can help homeopathic investigators design better products and improve reproducibility from study to study.^68,112–114 On the other hand, homeopaths possess over two centuries of practical clinical experience and texts on using their naturally-sourced nanoparticles safely to treat patients. Modern nanomedicine could benefit from these real-world homeopathic experiences with nanoparticle-based clinical practice. Multiple studies on cancer cell cultures and animals indicate that both modern nanomedicines and homeopathic remedies have beneficial effects in vitro and in animals toward promoting apoptosis and modulating biological signaling pathways to limit cancer cell growth.^115–117 Accelerating targeted research and identifying optimal treatments for people with cancer could result.

Table 2 lists relevant studies that suggest parallels between some mainstream natural product nano-medicine agents and homeopathic remedy effects. The evidence to date suggests that nanoparticle forms of a number of natural products can treat cancer. For instance, nanoparticles from certain mineral salts such as calcium phosphate,^31,118 the metalloid arsenic,¹³⁵ a variety of specific plant extracts (concentrated mother tinctures),9 animal venom toxin treatments,^{103–105,136} and exosomes (endogenous nanoparticles released by bodily cells) from cancerous tissue or dendritic cells of the immune system⁶ can all exert antiproliferative and pro-apoptotic effects on specific cancer cell lines in in vitro. Several plant nanoparticle studies used homeopathic mother tinctures to manufacture the nanoparticles.⁹ Moreover, studies of specific homeopathic remedies prepared in potencies ranging from 3X to 1000C (1M) made from mineral salts (calcium phosphate), certain plants, and cancerous tissue and used in clinical treatment of people with cancer also reveal similar effects.^1,2,109,110

As noted above, homeopathy potentially brings to integrative clinical nanomedicine treatment for cancer a well-described practice theory and more than 200 years of clinical experience. For homeopathy, the data indicate high patient satisfaction, very low toxicity, no drug-drug or drug-herb interactions, and low side effect rates.^95,96 Allergic reactions at low potencies may be a minor risk,^137,138 though the rates appear to be extremely low, serious events are rare, and relatedness to the remedies per se uncertain.^96,139,140 In one sense, homeopaths in clinical practice may be many years ahead of conventional physicians in applied understanding of how and when to use nanoparticles of natural products for safe and effective clinical treatment.

HOMEOPATHIC REMEDIES IN CANCER CARE

Although there is a growing research literature on the effects of homeopathic remedies on cancer in cell culture and animal studies, there are very few clinical trials of homeopathy in cancer patients. Most reports in the literature involve case reports.^2,141 A long-articulated concern of mainstream healthcare providers has been the presumption that homeopathy and other forms of complementary and alternative interventions are ineffective and could dangerously cause patients to delay more effective conventional treatments (ie, conventional chemotherapy, radiation therapy, surgery) of life-threatening serious diseases such as cancer. Partly as a result, homeopathic cancer research in Western countries has largely confined itself to preclinical studies and evaluations of adjunctive treatments of the side effects of conventional cancer treatments.¹⁴²

In that context, one small double-blind placebo-controlled trial showed significant benefits of a complex combination homeopathic remedy Traumeel (Heel, GmbH, Baden-Baden, Germany) for treating chemotherapy-induced stomatitis in children undergoing stem cell transplantation.¹⁴³ A positive phase III randomized clinical trial on 254 patients demonstrated that homeopathic Calendula was significantly more effective in preventing acute dermatitis during adjuvant radiation therapy than a standard of care topical agent.¹⁴⁴ An observational study of individualized homeopathy for radiation-induced itching in breast cancer patients suggested that homeopaths identified several other specific beneficial remedies for 21 out of 25 individuals.¹⁴⁵

Other trials of specific remedies for specific conventional cancer treatment side effects were negative or mixed, suggesting either lack of benefit or homeopathic and researcher limitations in choosing and/or managing the correct remedies.^142,146,147 The emergent conclusion from considering both the general and cancer-related homeopathic research literatures is that, as in conventional medicine, proper selection of the correct medicine for a given patient with a given clinical condition makes a difference as to whether or not homeopathic treatments are likely to work. The heterogeneity of patients, diagnoses, and remedy and potency effects make it essential to begin with tapping extensive clinical experience in designing research on homeopathic remedies and cancer that has reasonable face, model, and external validity.¹⁴⁸

THE BANERJI PROTOCOLS: USING HOMEOPATHIC REMEDIES TO TREAT CANCER

What is the experience of homeopaths in more comprehensive treatment of patients with cancer? India is a country with perhaps the most extensive history in this regard. In contrast with countries such as the United States or United Kingdom, India maintains more than 100 teaching institutions on homeopathy, many associated with universities, including 4- or 5-year homeopathic medical schools. These facilities include hospitals and homeopathic pharmacies, and all government hospitals include homeopathic treatment. Private practitioners often develop large clinics staffed by multiple homeopathic physicians, treating thousands of patients for all types of acute and chronic conditions, including cancers. Several different homeopathic approaches to treating all types of cancers have evolved in this context.^1,3,4

Only one such approach, the Banerji Protocols, however, has submitted its clinical cases to successful review in the Best Case Series Program of the National Cancer Institute (NCI) in the United States.^2,149 After this review, NCI’s Office of Cancer Complementary and Alternative Medicine prioritized additional research on this treatment approach. Nonetheless, historical skepticism about the nature and plausibility of homeopathic remedies as biologically active agents previously limited interest in pursuing research on homeopathy in the United States. The emerging data on the natural nano-medicine nature of homeopathic remedies is beginning to shift the discussion.

The Banerji Protocols are based on the cumulative experience of three generations of homeopaths treating thousands of patients.¹ It is an empiric treatment system developed through careful analysis of observed trends in patient-medicine interaction. These extensive practical experiences ultimately led to standardized disease or symptom-specific protocols for prescribing homeopathic medicines. This standardization of treatment has made it possible to apply rigorous scientific methods to test its efficacy. Collaborators from around the world have recently organized a consortium to coordinate their various efforts to advance the clinical and laboratory research on the Banerji Protocols. Because of their reputation for effective clinical treatment of many cancers that generally have a poor prognosis, we seek to apply the principles of nanoparticle behavior to the particular approach used in these protocols.

Given that an average of 120 to 200 cancer cases a day are treated at the PBH Research Foundation, Kolkata, India, there is a fertile ground for further investigation of this treatment method. A majority of the cancer cases treated at this facility are not treated with any other therapy, although there is no explicit requirement that this be so. In fact, most of the thousands of consultations that are provided to patients from other countries are from patients who have already had or are currently undergoing conventional Western treatment. Concomitant or previous conventional cancer treatment is not considered to be a contraindication to the Banerji Protocols.

However, a recent case review conducted by one of our authors (Sarter, unpublished data) revealed that for all categories of brain neoplasms, the cases that were treated with the Banerji Protocols alone (1) fared substantially better in terms of fewer adverse events than those that were combined with conventional Western treatment and (2) had median survival estimated by the Kaplan Meier method comparable to those reported in the Surveillance, Epidemiology, and End Results database of the NCI (http://seer.cancer.gov/). This provides support for the premise that homeopathic nanomedicines stimulate a robust host-dependent immune response from healthy cells that is typically impaired by chemotherapy and radiation therapy.¹⁵⁰

Other distinguishing characteristics of the Banerji Protocol are (1) its combination of multiple medicines into a treatment regimen, (2) repeated daily or weekly dosing over many months, and (3) the actual mixing together of some homeopathic medicines into standardized combination remedies. All of these are in contradiction to traditional classical homeopathy’s principles of treatment.^66,151 The protocols for the different types of cancer are mostly customized according to the specific location, organ and tissue type, and the specific medicines, in their specific dilutions and dosage patterns, have been standardized after generations of experience.¹

Thus, it appears plausible that in addition to a general stimulation of the immune system, there is also a tumor-specific effect in which tumor cells are preferentially killed but normal cells preserved.^105,106 As noted above, nanoparticles are capable of these types of differential effects on diseased vs healthy cells.^31,106,108 One hypothesis for this phenomenon is the greater “leakiness” of blood vessels in tumors. As a result, malignant cells may permit greater uptake of nanomedicines as opposed to healthy cells.^16,152

Studies conducted to date in which specific tumor cell lines are treated with the Banerji Protocol medicines have supported this hypothesis. One report on the Banerji protocols109 described 15 patients diagnosed with documented intracranial tumors who were treated exclusively with the homeopathic remedies Ruta graveolens 6C and Calcarea phosphorica 3X without additional chemotherapy or radiation. Of these 15 patients, six of the seven who had glioma showed complete regression of the tumors. In this study, we also reported that these medicines stimulated induction of survival-signaling pathways in normal lymphocytes and induction of death-signaling pathways in brain cancer cells. Cancer cell death was initiated by telomere erosion and completed through mitotic catastrophe events.¹⁰⁹ Bulk herbal extract forms of Ruta Graveolens have also demonstrated the ability to exert antitumor effects, but with some caveats on possible risks from prolonged use at high doses.^{123,153–156} The ability to use low doses of Ruta in nanoparticle form might help reduce such risks.^123,126,157

More recently, Frenkel et al reported a study of four homeopathic remedies from the Banerji protocols for treating breast cancer.¹¹⁰ The remedies were tested against two human breast adenocarcinoma cell lines (MCF-7 and MDA-MB-231) and a cell line derived from immortalized normal human mammary epithelial cells. The homeopathic medicines exerted preferential cytotoxic effects against the two breast cancer cell lines, causing cell cycle delay/arrest and apoptosis. These effects were accompanied by altered expression of the cell cycle regulatory proteins, including downregulation of phosphorylated Rb and upregulation of the CDK inhibitor p27. These effects were likely responsible for the cell cycle delay/arrest as well as induction of the apoptotic cascade that manifested in the activation of caspase 7 and cleavage of PARP in the treated cells.¹¹⁰

Another distinguishing feature of the Banerji Protocols is the use of both very low and moderately high potency medicines within the same protocol. Very low homeopathically prepared potencies would fall into the mother tincture to 3X range, whereas moderately high potencies would fall into the 30C to 200C range. Dosing in the protocols is generally more frequent than in classical homeopathy, again, because experience has shown this combination pulsed dose approach to be more effective for cancer than the isolated single-dose method typical of classical homeopathy. It should be clarified that when speaking of the potency of a homeopathic medicine, the guiding principle is “less is more,” meaning the more serially diluted and succussed the medicine, the higher its potency and apparent duration of action.¹⁵⁸

Many of the protocols in use for cancer treatment involve the use of medicines that are low potency combined with a high potency. Very low potencies are likely to contain mainly remedy source nanoparticles reduced and stabilized (capped) by lactose. In nanotechnology, capping agents stabilize nanoparticles and keep them from aggregating or agglomerating once formed. Natural products such as sugars, eg, lactose, honey,¹⁵⁹ or ascorbic acid can serve as nanoparticle-reducing and capping agents in water-based solutions (Table 1).^160,161

In contrast, higher potencies would likely contain both remedy source nanoparticles and various nano-silica/nanosilicon structures from repeated rounds of multiple succussions in ethanolic solutions within glass containers.^69,85,86 As noted elsewhere, evidence shows that nanosilica and other nanoparticle carriers can enhance effects of traditional treatments for cancers such as snake venoms.^{103–105,120,162} Silica in nano-form is also generally effective as an adjuvant to boost cellular and immune responses to oral and other vaccines for various conditions.^{45,88,90,163,164}

Table 3 lists the Banerji protocols in use for some specific cancers. It is noteworthy that Calcarea phosphorica 3X is included in the protocols for two cancers with generally very poor prognoses: brain and bone. These same types of cancers have responded very well to the Banerji Protocols with cases verified by NCI.^1,2,109

Also noteworthy is the occurrence of complete regressions in a consistent pattern among most of the cancers treated by the Banerji Protocols. Retrospective data collected over a 1-year period on patients treated for lung, brain, and esophageal cancer showed that complete regressions ranged from 22% to 32% (Figure 4). A similar complete regression of approximately 33% of brain neoplasms, including glioblastoma multiforme, over a different 1-year period (2010) was observed after the data in Figure 4 were compiled (Sarter, unpublished data). Although spontaneous regressions are a known phenomenon in oncology, the percentage of complete remissions typically observed at the Prasanta Banerji Homeopathic Research Foundation certainly justifies further investigation of this approach.

PULSED DOSING, BIOLOGICAL SIGNALING MECHANISMS, AND LOW DOSES

Dosing in homeopathy involves the use of low doses and pulsed intermittent administrations. Interestingly, mainstream oncology has developed pulsed dosing regimens for the more toxic chemotherapy agents to allow recovery of healthy tissue between treatments. Pulsed dosing is also reported in experimental models using exosomes (endogenous vesicular nanoparticles) from cancer tumor, dendritic, or malignant ascitic cells for cancer vaccines.^38,165 The value of intermittent doses in homeopathy^166,167 may be to take advantage of the stimulus properties of the treatment agent and the endogenous adaptive capacity of the recipient biological system to restore healthier homeo-static balance.^{70,113,168,169}

A possible objection to the therapeutic value of homeopathic remedy nanoparticles might be that people are constantly exposed to low levels of natural and manmade nanoparticles without curative effects. In fact, at higher levels, certain nanoparticles are toxic and may contribute to various chronic diseases.^17,170 However, there are at least three necessary properties for a given stimulus to initiate endogenous adaptation and even amplification responses: (1) a salient and discrete signal that is recognized as a potential threat to survival of the organism, rising above (and then falling back to) background noise, rather than continuous exposure^{70,112,113,171–175}; (2) a sufficiently low dose of nanoparticles to serve as a danger signal or mild environmental stressor without inducing toxicity: eg a hormetic dose level (see below)^{70,168,176,177}; and (3) adequate time for the processes of cellular and organism adaptation and cross-adaptation to take hold, amplify effects, and evolve after cessation of the stimulus.^{112,178–183}

The proposed primary targets of homeopathic remedies are mediators of the stress response networks (nervous, endocrine, immune, metabolic) of the body.^70,112 The correct remedies or nanoparticles would serve as mild stressors to initiate hormesis (biological adaptation).^168,184,185 This conceptualization accommodates the use of very low, carefully timed doses.¹⁸⁶ It is also compatible with the work of other investigators showing that homeopathic remedies

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Khuda-Bukhsh¹¹⁵ originally proposed modulation of signal proteins as the mechanism by which homeopathic remedies can produce epigenetic changes and effects on regulatory pathways in stopping cancer cell proliferation and inducing apoptosis. Recently we extended this hypothesis to postulate that the pulsed dosing approach of homeopathy is a more general treatment strategy. This approach uses the biological signaling properties of remedies to initiate systemic adaptive changes across the organism as a whole.^70,112–114

The ability of nanoparticles to release exosomes^42,43 offers an initial focus for future research on homeopathic remedies as biological triggers for salutary responses against cancer. Exosomes have demonstrated cell-to-cell and systemic signaling properties.^39–42 nanoparticles also can enter cells and activate intracellular defense cascades^44,114 involving inflammasomes. Inflammasome protein activation leads to release of cytokines and other self-regulatory elements of the immune system.^45,89,189

Smaller sized nanosilica (eg, 15 nm diameter) can produce effects on global genomic hypomethylation, which might contribute to subtle modulation of epi-genetic expression.¹⁹⁰ Nanosilica also has the capacity for bottom-up self-assembly of three-dimensional nanostructure networks built upon biological templates. These biotemplates include living cells,^13,28 proteins,¹⁹¹ collagen,¹⁹² and/or DNA^{12,14,193–195} itself. Self-assembly processes involving silica in homeopathic remedies might add additional means of amplifying, reproducing, and transmitting structural and perhaps electromagnetic information^196,197 of specific remedies in higher potency.

Hours of agitation via sonication in different solvents can also create extremely small, light-emitting tunable silicon nanoparticles (quantum dots).⁹³ Some silicon nanomaterials already play emerging roles as not only drug-delivery vehicles,¹⁹⁸ but also semiconductors in microelectronics memory, bioimaging, and nanocatalysis applications.¹⁹⁹ The possible role of homeopathically succussed nanosilicon and nanosilica per se in retaining and transmitting some of the remedy source-specific information at higher homeopathic potencies remains to be explored.^196,197

Hormesis is the well-documented phenomenon of nonlinear dose-response relationships. In hormesis, a low dose of an agent can stimulate beneficial responses whereas higher doses cause inhibitory or adverse effects.²⁰⁰ Depending on the nature of the substance, the dose size cutoff point for defining below the toxic level or “no observed adverse effect level” (NOAEL) can vary. In the oncology literature, low dose arsenic has been found to produce anticancer effects, whereas higher, more toxic doses can cause cancer.²⁰¹ Recent research demonstrates that a nanoform of arsenic tri-oxide further improves efficacy against breast cancer202 and lymphoma while protecting fertility in mice.¹¹⁹ In homeopathic form, arsenic trioxide is the widely used remedy Arsenicum album.^203–205

Some investigators have proposed that repeated intermittent mild stressors may improve resilience against future more intense stressors and foster longevity via epigenetic adaptations.^177,188,206
Figure 5 highlights the concept of “optimal stress.”²⁰⁷ With sufficient adaptive capacity, an organism can make modest overcompensations to a mild stressor that counteract the immediate effects and strengthen it against future onslaughts. The latter process would involve hormesis. However, more intense, frequent, or prolonged stress would instead overwhelm and kill the system or bring about chronic disease.^170,208,209

The Banerji protocols also raise new questions. For instance, are there differences in effects and/or mechanisms of low- vs high-potency remedies? Are there differences in the sizes, shapes, and properties of remedy nanoparticles at low vs high potencies? The use of lowpotency Calcarea phosphorica in combination with other higher-potency remedies may provide a generalized nanoparticulate biological augmentation strategy. Calcarea phosphorica 3X is a very low-potency form of calcium phosphate remedy, still well within the range of homeopathic dilutions that would leave both bulk form and nanoform source materials together with mechanically milled lactose⁷⁸ in any given dose. Nanomedicine research has repeatedly shown anticancer properties of nanoparticulates of this mineral salt source substance for a variety of cancers, including glioma, osteosarcoma, leukemia, and gastric and liver malignancies (Table 2).

However, the Banerji protocols also use much higher potencies of plant and cancer nosode remedies (ie, more highly diluted and succussed, with only source nanoparticles and presumably no residual source bulk form material remaining). Higher remedy potencies also typically contain glass-derived silica and/or silicon in bulk and nano forms.^85,86 Are there optimal potencies for eliciting the best anticancer effects with the lowest risks? Basic science studies on homeopathic remedies in non-cancer models suggest that this may be the case.^210,211 Consecutive potencies appear not to exhibit linear dose-response relationships but rather oscillatory or sinusoidal bidirectional types of nonlinear curves.^211,212

Knowing the composition of a material will not always reliably predict the nature or direction of its effects in nanoparticulate form.²¹³ A large body of research on the properties of top-down manufactured nanoparticles suggests that their properties are highly sensitive to slight variations in size, shape, defects, and surface charge.^{9,22,31,82,97,214} Such structural variables may be contributing in complex ways to remedy effects and variability from study to study or patient to patient.¹¹² The complex adaptive network nature of living systems, including human beings and animals, adds the likelihood of state-dependent nonlinear dynamical processes in the nature of the interactive response to any salient exogenous biological signal.^70,215 Even conventional nanomaterials can still convey therapeutic effects at very low doses when tested.²¹⁶

Furthermore, the Banerji Protocols use multiple remedies at the same time, an approach that diverges from classical homeopathic practice.¹ However, the evidence from mainstream oncology research suggests the potential therapeutic value of combining multiple therapies to overcome epigenetic-based resistance to any single intervention or cancer type.^217–219 Studying the incremental or synergistic effects of various single vs combinations of remedies on specific cancer cell lines would therefore be a crucial component of future research programs in this area. Earlier research on the combination remedy Canova supports this possibility. Canova originally contained a fixed combination of four or five different homeopathic remedies to target various cancers and infections. The current Canova formula for immune support in the United States includes 17 remedies, including homeopathic arsenic trioxide (Arsenicum Album 17X), a snake venom (Lachesis mutus 18X), silica (Silicea 18X), and the plant Thuja occidentalis 16X; see also Table 2).

Human beings have a limited repertoire of ways in which their bodies can react to stressors or disease processes.²²⁰ Various cancers, for example, may involve maturation arrest of pluripotential stem cells and/or dedifferentiation of mature cells.^221,222 Thus, need for the full person–focused individualization of remedy selection in classical homeopathy may become clinically less essential in the setting of neoplastic cells. The Banerji Protocols and other homeopathic cancer treatment programs, therefore, may represent a valid approach for using homeopathic remedies to address the usual clinical presentation of a given cancer. In this type of disease, many patients will show limited, circumscribed variants of possible mechanisms and symptom manifestations. At the same time, various classical homeopaths in India and other countries also claim extraordinary case reports of positive outcomes in individualized homeopathic treatment of some of their own cancer patients.^203,223

NEXT STEPS

Existing research expertise on the biological effects of homeopathic remedies on cancer cells can inform the design of new nanomedicine studies on ways to use less toxic natural products in cancer treatment.⁵ Available data point to the need for studies on the possible role of exosomes in the initial interface of homeopathic remedies as nanoparticles conveying salient biological signals to bodily cells. Comparison of effects from (1) traditionally made homeopathic remedies such as the mineral salt Calcarea phosphorica,¹⁰⁹ plant remedy Gelsemium sempervirens,⁶⁴ and the nosode breast cancer tumor remedy Carcinosin¹¹⁰ with (2) modern nanoparticles such as calcium phosphate nanoparticles,³¹ nano-encapsulated Gelsemium extract,⁶⁵ and breast cancer tumor–derived exosomes6 would be useful. Techniques such as nanoparticle tracking analysis,^224,225 scanning electron microscopy, and ultraviolet visual and Raman spectroscopy^226,227 combined with fluorescent-labeled antibodies provide contemporary research tools to evaluate and characterize exosomes released during cell interactions with remedies and nanoparticulates.^225,228,229

Finally, although the Banerji Protocols from India involve more diagnosis-related remedy selection than classical homeopathy, they still employ a flexible, albeit limited, set of remedies, partially individualized in their approach to specific types of cancers and associated symptoms. From a public health perspective, the Banerji approach strikes a pragmatic balance between the ideals of complete individualization of remedy selection in classical homeopathic constitutional prescribing⁷¹ and the need for broader accessibility of homeopathic treatment to large, often indigent, populations worldwide.

The systemization of the Banerji approach also might permit dissemination to busy integrative clinicians who may lack the years of detailed homeopathic education needed for accurate constitutional remedy selection and case management in classical homeopathic practice.¹⁴⁷ A larger number of integrative healthcare providers can learn the essential decision trees of the Banerji Protocols¹ as compared with classic alhomeopathy. Nonetheless, systematic comparative effectiveness studies of the Banerji Protocols vs (1) fully individualized classical homeopathic treatment and (2) conventional drugs and radiation treatment would better reveal the optimal clinical strategies.

Key next steps for preclinical and clinical research could involve the following.

• Replicating and extending electron microscopy studies on homeopathic remedies in independent laboratories to focus on Banerji Protocol remedies and specific homeopathic remedies previously demonstrated to exhibit antineoplastic effects in vitro or in vivo.

• Systematically applying widely used nanoparticle characterization methods to evaluate effects of varying pH, temperature, ethanol concentration, dilution procedures, succussion methods, glass-ware, and age of solution on the size, shape, stability, and biological effects of nanoparticles in specific homeopathic remedies made from plants, minerals, animal venoms, and malignant tumor cells. Methods would include

  • – measuring particle zeta potentials, dynamic light scattering (DLS), and conducting nanoparticle tracking analysis (NTA) of remedies^192,224,230 and

  • – characterizing and comparing homeopathic medicine potencies found most effective in the Banerji protocols^1,216 with other potencies of the “same” medicine, given evidence in previous research that all potencies of a given agent are not comparably active^231,232 and that nanocluster size can lead to nonlinear dose-response findings.²²

• Identifying biochemical or physiological biomarkers used in conventional cancer research to use for testing dose-response relationships of specific homeopathic remedies.

  • – A wide range of doses from possible beneficial hormetic range to toxic should be evaluated

  • – Exosome release, inflammasome proteins and cytokine activation patterns are possible biomarker candidates in addition to known mediators involved in blocking cancer cell proliferation and acilitating apoptosis of malignant cells.

• Using cell culture and animal models to determine the comparative advantages and disadvantages of homeopathically prepared vs modern manufactured nanoparticle forms and doses of specific natural products found most promising from outcomes study data.

• Pursuing clinical outcomes studies, comparative effectiveness trials, and randomized controlled trials based on the most promising Banerji Protocols for specific cancers. Candidate conditions include brain tumors (gliomas, glioblastomas multiforme) and osteosarcomas.

CONCLUSIONS

The overlaps between the manufacturing, nature, and properties of nanoparticles and those of homeopathic remedies merit additional examination.^70,112–114 Given the recent empirical findings of source nanoparticles at low and high potencies of metal⁶⁸ and plant⁶⁹ homeopathic remedies and even some homeopathically prepared conventional drugs,²¹² the similarities in effects of nanoparticles and homeopathic remedies on cancer cell lines add rationale for further investigation. The fact that many homeopathic remedies begin as source materials milled/ground in lactose for hours makes initial generation of top-down nanoparticles obligatory.⁹⁸ The documented ability of (1) succussions to release silica and nanosilica from the inside walls of glassware⁸⁵ and (2) plant mother tinctures to biosynthesize nanoparticles from silica⁵⁵ or metal precursors^9,233 in solution offer additional routes for making other types of nanoparticles in liquid remedies. Succussions, like sonication,⁸⁴ could also disperse larger nanoparticles into smaller particles.

Once formed, nanoparticles accumulate heterogeneously in colloidal solution and are transferred from container to container after succussions during homeopathic manufacturing procedures.⁶⁷ These data empirically address the main historical objection of skeptics to the persistence of specific source material in higher homeopathic dilutions. Based on nanotechnology,²¹⁴ it is also possible that either (1) the remedy nanoparticles attach to, coat, dope, and/or modify the silica and silicon nanoparticles at the “higher” liquid potencies or (2) some silica nanoparticles form shells around the remedy source nanoparticle cores as templates. With or without attachment of remedy source materials to silica and/or silicon nanoparticles, nonhomeopathy studies show that silica nanoparticles⁸⁵ can augment anticancer effects of traditional natural products such as snake venom^103–105 and activate heightened immune responsivity to very low quantities of antigens¹⁶⁴ and vaccines overall.^88,89

Overall, the Banerji cancer protocols raise integrative healthcare possibilities for blending the traditional clinical wisdom of experienced homeopathic practitioners from India on how to select and dose nanoparticulates for cancer treatment with the advanced contemporary methods of manufacturing nanoparticles using more replicable modern nanotechnology. Together, these concepts and tools suggest the possibility of accelerating evidence-based advances in natural product nanomedicine for treatment of people with cancer.

AUTHORS’ CONTRIBUTIONS

This article began with discussions among the authors about the Banerji protocols and their interest in pursuing systematic and rigorous research to follow up the National Cancer Institute Best Case Series findings. IRB initially drafted the article; BS, PB, and PB drafted the section on the Banerji Protocols. MK edited the article for clarity and context of integrative cancer care in complex adaptive systems. SJ and JI edited the information on biological effects of nanoparticles and homeopathic remedies. All authors edited, revised, and approved the final article.

Acknowledgments

Notes

Disclosure The authors completed the ICMJE Form for Disclosure of Potential Conflicts of Interest, and Drs Kothan, Sarter, Banerji, Jain, and Ives disclosed no potential conflicts of interest. Dr Bell disclosed that she is a consultant to Standard Homeopathic/Hylands Inc, a United States–based manufacturer of homeopathic medicines. Dr Bell also disclosed funding to her institution from the National Institutes of Health (NCCAM T32).

Contributor Information

Iris R. Bell, Department of Family and Community Medicine, The University of Arizona College of Medicine, Tucson (Dr Bell), United States. College of Nursing, The University of Arizona (Dr Bell), United States.

Barbara Sarter, Hahn School of Nursing and Health Sciences, University of San Diego, California, and Bastyr University – California (Dr Sarter), United States.

Mary Koithan, College of Nursing, The University of Arizona (Drs Koithan), United States.

Prasanta Banerji, PBH Research Foundation, Kolkata, India (Drs Banerji), India.

Pratip Banerji, PBH Research Foundation, Kolkata, India (Drs Banerji), India.

Shamini Jain, Samueli Institute, Alexandria, Virginia (Dr Jain), United States.

John Ives, Samueli Institute, Alexandria, Virginia (Dr Ives), United States.

REFERENCES