Efficacy and safety results with the combination therapy of arsenic trioxide, dexamethasone, and ascorbic acid in multiple myeloma patients: a phase 2 trial

High-dose vitamin C as a metabolic treatment of cancer: a new dimension in the era of adjuvant and intensive therapy

The anti-cancer mechanism of High-dose Vitamin C (HDVC) is mainly to participate in the Fenton reaction, hydroxylation reaction, and epigenetic modification, which leads to the energy crisis, metabolic collapse, and severe peroxidation stress that results in the proliferation inhibition or death of cancer cells. However, the mainstream view is that HDVC does not significantly improve cancer treatment outcomes. In clinical work and scientific research, we found that some drugs or therapies can significantly improve the anti-cancer effects of HDVC, such as PD-1 inhibitors that can increase the anti-cancer effects of cancerous HDVC by nearly three times. Here, the adjuvant and intensive therapy and synergistic mechanisms including HDVC combined application of chemoradiotherapies multi-vitamins, targeted drugs, immunotherapies, and oncolytic virus are discussed in detail. Adjuvant and intensive therapy of HDVC can significantly improve the therapeutic effect of HDVC in the metabolic treatment of cancer, but more clinical evidence is needed to support its clinical application.

High-Dose Vitamin C in Advanced-Stage Cancer Patients

High-dose intravenously administered vitamin C (IVC) is widely used in cancer patients by complementary and alternative medicine practitioners. The most frequent indications for IVC therapy result from the belief in its effectiveness as a potent anti-cancer agent which additionally enhances chemosensitivity of cancer cells and reduces chemotherapy-related toxicities and fatigue intensity. In this narrative review, we decided to deal with this issue, trying to answer the question whether there is any scientific evidence supporting the rationale for application of high-dose IVC therapy in advanced-stage cancer patients. Although results obtained from preclinical studies demonstrated that millimolar ascorbate plasma concentrations achievable only after IVC administration were cytotoxic to fast-growing malignant cells and inhibited tumor growth as well as prolonged the survival of laboratory animals, such positive effects were not found in human studies with advanced-stage cancer patients. We also have not found the rationale for the use of IVC to increase the effectiveness of chemotherapy and to reduce the chemotherapy-induced toxicity in the above mentioned group. Nevertheless, in palliative care, high-dose IVC might be considered as a therapy improving the quality of life and reducing cancer-related symptoms, such as fatigue and bone pain. However, because of the absence of placebo-controlled randomized trials on IVC efficacy in advanced-stage cancer patients, the placebo effect cannot be excluded.

Intravenous vitamin C for reduction of cytokines storm in acute respiratory distress syndrome

The recent outbreak of Covid19 has required urgent treatments for numerous patients. No suitable vaccines or antivirals are available for Covid19. The efficiency against Covid19 of WHO therapies of choice, that are two antivirals developed for other pathologies, is controversial. Therefore, alternative approaches are required. Intravenous (IV) Vitamin C (Vit-C) has emerged as one of the other alternatives for this purpose. Here we review the effects of IV Vit-C on the immune system response, the antiviral properties of IV Vit-C, and finally the antioxidant properties of IV Vit-C to specifically address the cytokines' storm characteristic of the Acute Respiratory Distress Syndrome (ARDS) that occur in the later cycle of the Covid19 infectious disease.

High doses of sodium ascorbate interfere with the expansion of glioblastoma multiforme cells in vitro and in vivo

AIMS

Constant development of chemotherapeutic strategies has considerably improved the efficiency of tumor treatment. However, adverse effects of chemotherapeutics enforce premature treatment cessation, which leads to the tumor recurrence and accelerated death of oncologic patients. Recently, sodium ascorbate (ASC) has been suggested as a promising drug for the adjunctive chemotherapy of glioblastoma multiforme (GBM) and prostate cancer (PC). To estimate whether ASC can interfere with tumor recurrence between the first and second-line chemotherapy, we analyzed the effect of high ASC doses on the expansion of cells in vitro and in vivo.

MAIN METHODS

Brightfield microscopy-assisted approaches were used to estimate the effect of ASC (1-14 mM) on the morphology and invasiveness of human GBM, rat PC and normal mouse 3T3 cells, whereas cytostatic/pro-apoptotic activity of ASC was estimated with flow cytometry. These assays were complemented by the in vitro CellROX-assisted analyses of intracellular oxidative stress and in vivo estimation of GBM tumor invasion.

KEY FINDINGS

ASC considerably decreased the proliferation and motility of GBM and PC cells. This effect was accompanied by intracellular ROS over-production and necrotic death of tumor cells, apparently resulting from their "autoschizis". In vivo studies demonstrated the retardation of GBM tumor growth and invasion in the rats undergone intravenous ASC administration, in the absence of detectable systemic adverse effects of ASC.

SIGNIFICANCE

Our data support previous notions on anti-tumor activity of high ASC doses. However, autoschizis-related cell responses to ASC indicate that its application in human adjunctive tumor therapy should be considered with caution.

Phase I study of high-dose ascorbic acid with mFOLFOX6 or FOLFIRI in patients with metastatic colorectal cancer or gastric cancer

Background

Preclinical studies suggest synergistic effectiveness of ascorbic acid (AA, vitamin C) and cytotoxic agents in gastrointestinal malignancies. This phase 1 study aimed to establish the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of AA combined with mFOLFOX6 or FOLFIRI regimens in patients with metastatic colorectal cancer (mCRC) or gastric cancer (mGC).

Methods

In the dose-escalation phase, patients received AA (0.2–1.5 g/kg, 3-h infusion, once daily, days 1–3) with mFOLFOX6 or FOLFIRI in a 14-day cycle until the MTD was reached. In the speed-expansion phase, AA was administered at the MTD or at 1.5 g/kg if the MTD was not reached at a fixed rate of 0.6, 0.8 or 1 g/min. Pharmacokinetics and preliminary efficacy were also assessed.

Results

Thirty-six patients were enrolled. The MTD was not reached. The RP2D was established as AA at 1.5 g/kg/day, days 1–3, with mFOLFOX6 or FOLFIRI. No dose-limiting toxicity (DLT) was detected during dose escalation. The most common treatment-emergent adverse events (TRAEs) were sensory neuropathy (50%), nausea (38.9%), vomiting (36.1%) and neutropenia (27.8%). Grade 3–4 TRAEs were neutropenia (13.9%), sensory neuropathy (2.8%), vomiting (2.8%), diarrhea (2.8%) and leukopenia (2.8%). AA exposure was dose-proportional. The objective response rate was 58.3%, and the disease control rate was 95.8%. No difference in efficacy was found between mCRC patients with wild-type RAS/BRAF and mutant RAS or BRAF.

Conclusions

The favorable safety profile and preliminary efficacy of AA plus mFOLFOX6/FOLFIRI support further evaluation of this combination in mCRC or mGC.

Trial registration

ClinicalTrial.gov Identifier: NCT02969681.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5696-z) contains supplementary material, which is available to authorized users.

Ascorbic Acid in Colon Cancer: From the Basic to the Clinical Applications

Given the safety and potential benefits of intravenous ascorbic acid (AA) administration in cancer patients, there is merit in further exploring this therapeutic concept. In this review, we discuss the potential benefits of intravenous AA administration on colorectal cancer and we specifically focus on its effect on glycolysis in mutant and wild type RAS. We perform a PubMed and Ovid MEDLINE search using ascorbic acid, intravenous vitamin C, KRAS mutation, BRAF mutation and colorectal cancer (CRC) as keywords. At the cellular level, colorectal cancer cells undergo a metabolic shift called the Warburg effect to allow for more glucose absorption and utilization of glycolysis. This shift also allows AA to enter which leads to a disruption in the Warburg effect and a shutdown of the downstream KRAS pathway in mutated KRAS colon cancer cells. At the clinical level, AA is associated with tumour regression in advanced disease and improved tolerability and side effects of standard therapy. Based on these findings, we conclude that further clinical trials are needed on a larger scale to examine the therapeutic benefits of AA in colon cancer.

Systematic Review of Intravenous Ascorbate in Cancer Clinical Trials

Background: Ascorbate (vitamin C) has been evaluated as a potential treatment for cancer as an independent agent and in combination with standard chemotherapies. This review assesses the evidence for safety and clinical effectiveness of intravenous (IV) ascorbate in treating various types of cancer. Methods: Single arm and randomized Phase I/II trials were included in this review. The PubMed, MEDLINE, and Cochrane databases were searched. Results were screened by three of the authors (GN, RP, and CJP) to determine if they met inclusion criteria, and then summarized using a narrative approach. Results: A total of 23 trials involving 385 patients met the inclusion criteria. Only one trial, in ovarian cancer, randomized patients to receive vitamin C or standard of care (chemotherapy). That trial reported an 8.75 month increase in progression-free survival (PFS) and an improved trend in overall survival (OS) in the vitamin C treated arm. Conclusion: Overall, vitamin C has been shown to be safe in nearly all patient populations, alone and in combination with chemotherapies. The promising results support the need for randomized placebo-controlled trials such as the ongoing placebo-controlled trials of vitamin C and chemotherapy in prostate cancer.

Realgar nanoparticles versus ATO arsenic compounds induce in vitro and in vivo activity against multiple myeloma

Multiple myeloma (MM), a B cell malignancy characterized by clonal proliferation of plasma cells in the bone marrow, remains incurable despite the use of novel and conventional therapies. In this study, we demonstrated MM cell cytotoxicity triggered by realgar (REA; As₄ S₄ ) nanoparticles (NREA) versus Arsenic trioxide (ATO) against MM cell lines and patient cells. Both NREA and ATO showed in vivo anti-MM activity, resulting in significantly decreased tumour burden. The anti-MM activity of NREA and ATO is associated with apoptosis, evidenced by DNA fragmentation, depletion of mitochondrial membrane potential, cleavage of caspases and anti-apoptotic proteins. NREA induced G₂ /M cell cycle arrest and modulation of cyclin B1, p53 (TP53), p21 (CDKN1A), Puma (BBC3) and Wee-1 (WEE1). Moreover, NREA induced modulation of key regulatory molecules in MM pathogenesis including JNK activation, c-Myc (MYC), BRD4, and histones. Importantly, NREA, but not ATO, significantly depleted the proportion and clonogenicity of the MM stem-like side population, even in the context of the bone marrow stromal cells. Finally, our study showed that both NREA and ATO triggered synergistic anti-MM activity when combined with lenalidomide or melphalan. Taken together, the anti-MM activity of NREA was more potent compared to ATO, providing the preclinical framework for clinical trials to improve patient outcome in MM.

Advances in Synergistic Combinations of Chinese Herbal Medicine for the Treatment of Cancer

The complex pathology of cancer development requires correspondingly complex treatments. The traditional application of individual single-target drugs fails to sufficiently treat cancer with durable therapeutic effects and tolerable adverse events. Therefore, synergistic combinations of drugs represent a promising way to enhance efficacy, overcome toxicity and optimize safety. Chinese Herbal Medicines (CHMs) have long been used as such synergistic combinations. Therefore, we summarized the synergistic combinations of CHMs used in the treatment of cancer and their roles in chemotherapy in terms of enhancing efficacy, reducing side effects, immune modulation, as well as abrogating drug resistance. Our conclusions support the development of further science-based holistic modalities for cancer care.

A phase II study of arsenic trioxide in patients with relapsed or refractory malignant lymphoma

Limited data have been reported regarding the use of arsenic trioxide (ATO) in the treatment of patients with relapsed or refractory malignant lymphoma; therefore, the present phase II study evaluated the efficacy and toxicity of ATO in such patients. A total of 35 patients were treated with ATO (0.25 mg/kg) infused for 1 h daily, 5 days a week, for a 6-week cycle. Patients were evaluated for the efficacy and toxicity of this regimen. The primary outcome evaluated was the overall response rate (ORR), including the complete and partial response rates. The secondary outcomes evaluated were the overall survival (OS), progression-free survival (PFS), and toxicity. Tumor response data were obtained from all 35 enrolled patients. The ORR was 43%, including complete responses in four patients (11%) and partial responses in 11 patients (31%). The median duration of response was 16 weeks (range 11-23 weeks). The median OS was 79 weeks (range 14-171 weeks), and the median PFS was 55 weeks (range 14-135 weeks). Grade I or II hematological toxicities were the most commonly reported adverse events. The results of this study appear promising for the treatment of relapsed or refractory malignant lymphoma, with well-tolerated ATO toxicity.

Is there a role for oral or intravenous ascorbate (vitamin C) in treating patients with cancer? A systematic review

BACKGROUND

Many cancer patients receive supplemental ascorbate (vitamin C) in the belief that it synergizes the anticancer effects of chemotherapy and reduces its toxicity.

METHODS

A systematic review was performed to evaluate the antitumor effects and toxicity of ascorbate treatment. Medline (1946 to March 2014), EMBASE (1947 to March 2014), and the Cochrane central register (1993 to March 2014) were searched for randomized and observational studies.

RESULTS

Of 696 identified records, 61 full-text articles were screened and 34 were included. In total, 5 randomized controlled trials (RCTs) (n = 322), 12 phase I/II trials (n = 287), 6 observational studies (n = 7,599), and 11 case reports (n = 267) were identified. Because of study heterogeneity, no meta-analyses were performed. No RCTs reported any statistically significant improvements in overall or progression-free survival or reduced toxicity with ascorbate relative to control arm. Evidence for ascorbate's antitumor effects was limited to case reports and observational and uncontrolled studies.

CONCLUSION

There is no high-quality evidence to suggest that ascorbate supplementation in cancer patients either enhances the antitumor effects of chemotherapy or reduces its toxicity. Given the high financial and time costs to patients of this treatment, high-quality placebo-controlled trials are needed.

Arsenic trioxide-based therapy in relapsed/refractory multiple myeloma patients: a meta-analysis and systematic review

Multiple myeloma (MM) is a clonal malignancy characterized by the proliferation of malignant plasma cells in the bone marrow and the production of monoclonal immunoglobulin. Although some newly approved drugs (thalidomide, lenalidomide, and bortezomib) demonstrate significant benefit for MM patients with improved survival, all MM patients still relapse. Arsenic trioxide (ATO) is the most active single agent in acute promyelocytic leukemia, the antitumor activity of which is partly dependent on the production of reactive oxygen species. Due to its multifaceted effects observed on MM cell lines and primary myeloma cells, Phase I/II trials have been conducted in heavily pretreated patients with relapsed or refractory MM. Therapy regimens varied dramatically as to the dosage of ATO and monotherapy versus combination therapy with other agents available for the treatment of MM. Although ATO-based combination treatment was well tolerated by most patients, most trials found that ATO has limited effects on MM patients. However, since small numbers of patients were randomized to different treatment arms, trials have not been statistically powered to determine the differences in progression-free survival and overall survival among the experimental arms. Therefore, large Phase III studies of ATO-based randomized controlled trials will be needed to establish whether ATO has any potential beneficial effects in the clinical setting.

Intravenous Vitamin C and Cancer: A Systematic Review

BACKGROUND

Intravenous vitamin C (IVC) is a contentious adjunctive cancer therapy, widely used in naturopathic and integrative oncology settings. We conducted a systematic review of human interventional and observational studies assessing IVC for use in cancer patients.

METHODS

We searched MEDLINE, EMBASE, The Cochrane Library, CINAHL, and AMED from inception to April 2013 for human studies examining the safety, effectiveness, or pharmacokinetics of IVC use in cancer patients.

RESULTS

Of 897 records, a total of 39 reports of 37 studies were included: 2 randomized controlled trials (RCTs), 15 uncontrolled trials, 6 observational studies, and 14 case reports. IVC dosing ranged from 1 g to more than 200 g ascorbic acid per infusion, typically administered 2 to 3 times weekly. IVC does not appear to increase toxicity or interfere with antitumor effects of gemcitabine/erlotinib therapy or paclitaxel and carboplatin. Based on 1 RCT and data from uncontrolled human trials, IVC may improve time to relapse and possibly enhance reductions in tumor mass and improve survival in combination with chemotherapy. IVC may improve quality of life, physical function, and toxicities associated with chemotherapy, including fatigue, nausea, insomnia, constipation, and depression. Case reports document several instances of tumor regression and long-term disease-free survival associated with use of IVC.

CONCLUSION

There is limited high-quality clinical evidence on the safety and effectiveness of IVC. The existing evidence is preliminary and cannot be considered conclusive but is suggestive of a good safety profile and potentially important antitumor activity; however, more rigorous evidence is needed to conclusively demonstrate these effects. IVC may improve the quality of life and symptom severity of patients with cancer, and several cases of cancer remission have been reported. Well-designed, controlled studies of IVC therapy are needed.

Arsenic trioxide inhibits the proliferation of myeloma cell line through notch signaling pathway

Arsenic Trioxide (ATO) has shown remarkable efficacy for the treatment of multiple myeloma (MM). However, the mechanism by which ATO exerts its inhibitory effect on the proliferation of myeloma cells remains to be clarified. We study the inhibitory effect of ATO at various concentrations on the proliferation of the myeloma cell line RPMI 8226 and discussed the molecular mechanism of ATO on myeloma cell line. Our results proved that ATO had a significant dose-dependent and time-dependent inhibitory effect on the expressions of the Notch receptor (Notch1) and Notch ligand (Jag2). Data from the real-time PCR assay showed that the mRNA expression levels of the Jag2 gene and its downstream gene Hes1 were both significantly down-regulated after the myeloma cells were treated with ATO while the expression of the tumor suppressor gene PTEN was up-regulated. These results elucidated the molecular mechanism underlying the ATO mediated inhibition of myeloma cell proliferation. This is the first report on the anti-myeloma activity in myeloma cells through inhibition of the Notch signaling pathway.

Alterations in glutathione levels and apoptotic regulators are associated with acquisition of arsenic trioxide resistance in multiple myeloma

Arsenic trioxide (ATO) has been tested in relapsed/refractory multiple myeloma with limited success. In order to better understand drug mechanism and resistance pathways in myeloma we generated an ATO-resistant cell line, 8226/S-ATOR05, with an IC50 that is 2–3-fold higher than control cell lines and significantly higher than clinically achievable concentrations. Interestingly we found two parallel pathways governing resistance to ATO in 8226/S-ATOR05, and the relevance of these pathways appears to be linked to the concentration of ATO used. We found changes in the expression of Bcl-2 family proteins Bfl-1 and Noxa as well as an increase in cellular glutathione (GSH) levels. At low, clinically achievable concentrations, resistance was primarily associated with an increase in expression of the anti-apoptotic protein Bfl-1 and a decrease in expression of the pro-apoptotic protein Noxa. However, as the concentration of ATO increased, elevated levels of intracellular GSH in 8226/S-ATOR05 became the primary mechanism of ATO resistance. Removal of arsenic selection resulted in a loss of the resistance phenotype, with cells becoming sensitive to high concentrations of ATO within 7 days following drug removal, indicating changes associated with high level resistance (elevated GSH) are dependent upon the presence of arsenic. Conversely, not until 50 days without arsenic did cells once again become sensitive to clinically relevant doses of ATO, coinciding with a decrease in the expression of Bfl-1. In addition we found cross-resistance to melphalan and doxorubicin in 8226/S-ATOR05, suggesting ATO-resistance pathways may also be involved in resistance to other chemotherapeutic agents used in the treatment of multiple myeloma.

From an old remedy to a magic bullet: molecular mechanisms underlying the therapeutic effects of arsenic in fighting leukemia

Arsenic had been used in treating malignancies from the 18th to mid-20th century. In the past 3 decades, arsenic was revived and shown to be able to induce complete remission and to achieve, when combined with all-trans retinoic acid and chemotherapy, a 5-year overall survival of 90% in patients with acute promyelocytic leukemia driven by the t(15;17) translocation-generated promyelocytic leukemia-retinoic acid receptor α (PML-RARα) fusion. Molecularly, arsenic binds thiol residues and induces the formation of reactive oxygen species, thus affecting numerous signaling pathways. Interestingly, arsenic directly binds the C3HC4 zinc finger motif in the RBCC domain of PML and PML-RARα, induces their homodimerization and multimerization, and enhances their interaction with the SUMO E2 conjugase Ubc9, facilitating subsequent sumoylation/ubiquitination and proteasomal degradation. Arsenic-caused intermolecular disulfide formation in PML also contributes to PML-multimerization. All-trans retinoic acid, which targets PML-RARα for degradation through its RARα moiety, synergizes with arsenic in eliminating leukemia-initiating cells. Arsenic perturbs a number of proteins involved in other hematologic malignancies, including chronic myeloid leukemia and adult T-cell leukemia/lymphoma, whereby it may bring new therapeutic benefits. The successful revival of arsenic in acute promyelocytic leukemia, together with modern mechanistic studies, has thus allowed a new paradigm to emerge in translational medicine.

Arsenic and its combinations in cancer therapeutics

Arsenic is a metalloid that is considered to be a paradox in terms of its role both as a carcinogen and as a therapeutic agent. Chronic exposure to arsenic in drinking water has been linked with the development of various pathological conditions including cancer. Nevertheless, the therapeutic potential of arsenic and its derivatives in a variety of diseases have been exploited in the past. However, its role and mechanism of action as a therapeutic agent still remain an active area of research and investigation. Our ongoing work also suggests varied responses in cancer cells exposed to lower versus higher concentrations of arsenic. Furthermore, the arsenic combinations with chemopreventive or anticancer agents have been observed to sensitize the cell for cell-cycle arrest and cell death. Here, we have provided the account of recent updates on the mechanism of action of arsenic and its derivatives that lead to various disorders, and its role as a therapeutic agent both as a single agent as well as in combination chemotherapy.

Arsenic trioxide - An old drug rediscovered

Over the last 17 years, clinical trials conducted worldwide have demonstrated the efficacy of arsenic trioxide (As(2)O(3)) in the treatment of relapsed acute promyelocytic leukemia (APL). Currently, the role of As(2)O(3) in front-line therapy is under investigation. Recent trials in the US have demonstrated that the addition of As(2)O(3) to standard treatment regimens improves survival outcomes in patients with APL and may allow a reduction in cytotoxic chemotherapy exposure. As(2)O(3) has also shown efficacy in other malignancies, particularly multiple myeloma and myelodysplastic syndromes. Therapeutic doses of As(2)O(3) are well tolerated, with no evidence of long-term toxicity. Adverse events include APL differentiation syndrome, electrocardiographic abnormalities, and mild elevations in liver enzymes. This review highlights trials investigating the role of As(2)O(3) in induction and consolidation for newly diagnosed APL, as well as its role in other hematologic malignancies. The chemistry, mechanisms of action, and clinical side effects of As(2)O(3) are also discussed.

Phase II study of arsenic trioxide and ascorbic acid for relapsed or refractory lymphoid malignancies: a Wisconsin Oncology Network study

Arsenic trioxide (As(2)O(3)) has established clinical activity in acute promyelocytic leukaemia and has pre-clinical data suggesting activity in lymphoid malignancies. Cell death from As(2)O(3) may be the result of oxidative stress. Agents which deplete intracellular glutathione, such as ascorbic acid (AA), may potentiate arsenic-mediated apoptosis. This multi-institution phase II study investigated a novel dosing schedule of As(2)O(3) and AA in patients with relapsed or refractory lymphoid malignancies. Patients received As(2)O(3) 0.25 mg/kg iv and AA 1000 mg iv for five consecutive days during the first week of each cycle followed by twice weekly infusions during weeks 2-6. Cycles were repeated every 8 weeks. The primary end point was objective response. In a subset of patients, sequential levels of intracellular glutathione and measures of Bcl-2 and Bax gene expression were evaluated in peripheral blood mononuclear cells during treatment. Seventeen patients were enrolled between March 2002 and February 2004. The median age was 71, and the majority of enrolled patients had non-Hodgkin's lymphoma (12/17). Sixteen patients were evaluable, and one patient with mantle cell lymphoma achieved an unconfirmed complete response after five cycles of therapy for an overall response rate of 6%. The trial, which had been designed as a two-stage study, was closed after the first stage analysis due to lack of activity. Haematologic toxicities were the most commonly reported events in this heavily pre-treated population, and comprised the majority of grade 3 and 4 toxicities. Intracellular depletion of glutathione was not consistently observed during treatment. As(2)O(3) and AA in this novel dosing strategy was generally well tolerated but had limited activity in patients with relapsed and refractory lymphoid malignancies.

Supplements for immune enhancement in hematologic malignancies

This brief review aims to discuss the various cellular immunological aspects and related mechanisms of the use of specific components from traditional herbal medicines. We begin with lessons learned from thalidomide as an effective single drug with multiple mechanisms of action to treat multiple myeloma. Examples of “supplements” or integrative therapy will be drawn from arsenic trioxide, medicinal mushrooms including Coriolus vesicular and Ganoderma lucidum, followed by the discussion of beta-glucans affecting various immunological important cellular subsets. Different classes of compounds may enhance distinct immune cell populations that might contribute to a multi-targeted holistic effects on anti-cancer treatment. Finally, we conclude by highlighting an herbal formulation PHY906 as a potential adjunct to chemotherapy that might become one of the first US Food and Drug Administration (FDA) approved oral herbal medicines for anti-cancer adjunct treatment.

Targeting MEK/MAPK signal transduction module potentiates ATO-induced apoptosis in multiple myeloma cells through multiple signaling pathways

We demonstrate that blockade of the MEK/ERK signaling module, using the small-molecule inhibitors PD184352 or PD325901 (PD), strikingly enhances arsenic trioxide (ATO)–induced cytotoxicity in human myeloma cell lines (HMCLs) and in tumor cells from patients with multiple myeloma (MM) through a caspase-dependent mechanism. In HMCLs retaining a functional p53, PD treatment greatly enhances the ATO-induced p53 accumulation and p73, a p53 paralog, cooperates with p53 in caspase activation and apoptosis induction. In HMCLs carrying a nonfunctional p53, cotreatment with PD strikingly elevates the (DR4 + DR5)/(DcR1 + DcR2) tumor necrosis factor (TNF)–related apoptosis-inducing ligand (TRAIL) receptors ratio and caspase-8 activation of ATO-treated cells. In MM cells, irrespective of p53 status, the combined PD/ATO treatment increases the level of the proapoptotic protein Bim (PD-mediated) and decreases antiapoptotic protein Mcl-1 (ATO-mediated). Moreover, Bim physically interacts with both DR4 and DR5 TRAIL receptors in PD/ATO-treated cells, and loss of Bim interferes with the activation of both extrinsic and intrinsic apoptotic pathways in response to PD/ATO. Finally, PD/ATO treatment induces tumor regression, prolongs survival, and is well tolerated in vivo in a human plasmacytoma xenograft model. These preclinical studies provide the framework for testing PD325901 and ATO combination therapy in clinical trials aimed to improve patient outcome in MM.

Complications of myeloma therapy

The advent of new therapies for multiple myeloma brings new hope for patients but also new side effects. Emerging information about the risks of supportive care therapies, including long-term, high-intensity bisphosphonate use and erythropoiesis-stimulating agents, is examined. As the number of drugs in the myeloma armamentarium grows, so does the list of possible side effects and interactions. With current progress, not only are there more complications to consider but patients are also living longer and the risk for delayed complications is becoming more relevant. The author provides perspective about the risks for the most active and commonly used single-agent and combination myeloma therapies.

Arsenical-based cancer drugs

Arsenic is a semi-metal or metalloid with two biologically important oxidation states, As(III) and As(V). As(III), in particular, reacts with closely spaced protein thiols, forming stable cyclic dithioarsinite complexes in which both sulfur atoms are bound to arsenic. It is this reaction that is mostly responsible for arsenics cytotoxicity. Arsenic compounds have been used as medicinal agents for many centuries for the treatment of diseases such as psoriasis, syphilis, and rheumatosis. From the 1700's until the introduction of and use of modern chemotherapy and radiation therapy in the mid 1900's, arsenic was a mainstay in the treatment of leukemia. Concerns about the toxicity of arsenical compounds led eventually to their abandonment for the treatment of cancer. The discovery in the 1980's that arsenic trioxide induces complete remission in a high percentage of patients with acute promyelocytic leukemia has awakened interest in this metalloid for the treatment of human disease. In particular, a new class or organoarsenicals are being trialed for the treatment of hematological malignancies and solid tumors. In this review, we discuss the arsenical-based compounds used in the past and present for the treatment of various forms of cancer. Mechanisms of action and selectivity and acute and chronic toxicities are discussed along with the prospects of this class of molecule.