ascorbic-acid and Multiple-Myeloma

Topics: Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Clinical Trials as Topic; Drug Combinations; Glutathione; Humans; Mitochondria; Multiple Myeloma; Oxides; Reactive Oxygen Species

Vitamin C is an important micronutrient for various immune cells. It increases phagocytic cell function and is necessary for T and natural killer (NK) cell development. Patients in need of an autologous hematopoietic stem cell transplantation (HSCT) are often vitamin C-depleted. We therefore hypothesized that vitamin C supplementation could improve immune recovery in autologous HSCT patients. This blinded, placebo-controlled trial included 44 patients randomized to receive vitamin C or a placebo. The following outcome measures used were clinical and immunological parameters, among others: time to neutrophil recovery, serum, and intracellular vitamin C values. Twenty-one patients received vitamin C, and 23 received a placebo. The time to neutrophil recovery did not differ between the two groups at 11.2 days (

Topics: Ascorbic Acid; Bacteremia; Hematopoietic Stem Cell Transplantation; Humans; Lymphoma; Multiple Myeloma; Neutrophils; Transplantation, Autologous; Vitamins

This Phase I study assessed the feasibility of concomitant arsenic trioxide (ATO), ascorbic acid (AA), and bortezomib (Velcade™) (AAV) for patients with relapsed/refractory multiple myeloma.. ATO (0.25 mg/kg) and AA (1 g) were given with an escalating dose of bortezomib (1 mg/m(2) or 1.3 mg/m(2) IV bolus on days 1 and 8 of a 21-day cycle).. Ten patients (median age 62 years), with a median of 3 prior regimens, were enrolled. Four (40%) patients achieved clinical benefit, with one patient achieving a durable partial response. No formal DLTs were encountered.. AAV combination was feasible and demonstrated some benefits in this heavily pretreated population.

Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Boronic Acids; Bortezomib; Female; Humans; Male; Middle Aged; Multiple Myeloma; Oxides; Pyrazines; Recurrence

Bortezomib is active for newly diagnosed and relapsed multiple myeloma, and it has synergistic activity with melphalan. The authors of this report conducted a randomized trial to determine the safety and efficacy of adding bortezomib to a preparative regimen of arsenic trioxide (ATO), ascorbic acid (AA), and melphalan.. Among 60 patients who enrolled between October 2006 and September 2007, 58 patients underwent autologous transplantation with a preparative regimen of melphalan 200 mg/m(2) intravenously, AA 1000 mg daily intravenously for 7 days, and ATO 0.25 mg/kg intravenously for 7 days. Patients were randomized to receive no bortezomib (Group 1), bortezomib 1 mg/m(2) × 3 doses (Group 2), and bortezomib 1.5 mg/m(2) × 3 doses (Group 3). Primary endpoints were complete response (CR), grade IV toxicity, and 90-day treatment-related mortality (TRM). Secondary endpoints were progression-free survival (PFS) and overall survival (OS).. The median follow-up of all surviving patients was 36 months (range, 20-43 months). The CR rates in Groups 1, 2, and 3 were 20%, 10%, and 10%, respectively. Grade 3 and 4 nonhematologic toxicities and TRM were comparable. The median OS was not reached in the groups, whereas the median PFS in Groups 1, 2, and 3 was 17.8 months, 17.4 months, and 20.7 months, respectively. PFS and OS were significantly shorter in patients who had high-risk cytogenetics (P = .016 and P = .0001, respectively) and relapsed disease (P = .0001 and P = .0001, respectively) regardless of the treatment group.. Adding bortezomib to a preparative regimen of ATO, AA, and high-dose melphalan was safe and well tolerated in patients with multiple myeloma. There was no significant improvement in the CR rate, PFS, or OS in the bortezomib groups.

Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Blood Transfusion, Autologous; Boronic Acids; Bortezomib; Disease-Free Survival; Drug Administration Schedule; Female; Follow-Up Studies; Hematopoietic Stem Cell Transplantation; Humans; Male; Melphalan; Middle Aged; Multiple Myeloma; Oxides; Prognosis; Pyrazines; Transplantation Conditioning

We conducted a single-arm, multicentre phase 2 study to evaluate bortezomib, ascorbic acid and melphalan (BAM) for patients with newly diagnosed multiple myeloma (MM).. Induction consisted of up to eight 28-d cycles of bortezomib 1.0 mg/m(2) on days 1, 4, 8 and 11, plus oral ascorbic acid 1 g and oral melphalan 0.1 mg/kg on days 1-4, followed by maintenance bortezomib 1.3 mg/m(2) every 2 wk until progression.. Among 35 patients enrolled (median age 70 yr), responses occurred in 23/31 evaluable patients (74%) including five (16%) complete, three (10%) very good partial, six (19%) partial and nine (29%) minimal responses. Six patients (19%) had stable disease. Thus, disease control was achieved in 29 (94%) patients. Median times to first and best responses were 2 and 3 months (ranges 1-5 and 1-7), respectively. Median time to progression was 19 months and median overall survival has not been reached (range 2-23+ months). Grade 3 and 4 adverse events occurred in 17 and 5 patients, respectively; the most common were neutropenia, neuropathy and thrombocytopenia.. BAM is an efficacious, well-tolerated and steroid- and immunomodulatory drug (IMiD)-free frontline treatment regimen for MM patients.

Topics: Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Ascorbic Acid; Boronic Acids; Bortezomib; Humans; Melphalan; Middle Aged; Multiple Myeloma; Pyrazines; Survival Analysis; Treatment Outcome

Arsenic trioxide (ATO) is synergistic with ascorbic acid (AA) and melphalan against myeloma both in vitro and in vivo. The aim of this randomized phase II trial was to determine the safety and efficacy of a combination of ATO, melphalan, and AA as preparative regimen in 48 patients undergoing autologous hematopoietic stem cell transplantation (ASCT) for multiple myeloma (MM). Forty-eight patients received melphalan 200 mg/m2 i.v. over 2 days and AA 1000 mg i.v. over 7 days in 3 treatment arms: no ATO (arm 1), ATO 0.15 mg/kg i.v. x 7 days (arm 2), and ATO 0.25 mg/kg i.v. x 7 days (arm 3). No dose-limiting toxicity, engraftment failure, or nonrelapse mortality (NRM) was seen in the first 100 days post-ASCT. Complete responses (CR) were seen in 12 of 48 patients (25%), with an overall response rate (ORR = CR + PR) of 85%. Median progression-free survival (PFS) was 25 months; median overall survival (OS) has not yet been reached. There was no significant difference in CR, PFS, or OS among the 3 treatment arms, and no adverse effect of ATO on melphalan pharmacokinetics. Addition of ATO + AA to high-dose melphalan is safe and well tolerated as a preparative regimen for MM.

Topics: Adult; Aged; Antineoplastic Agents; Antioxidants; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Disease-Free Survival; Female; Hematopoietic Stem Cell Transplantation; Humans; Male; Melphalan; Middle Aged; Multiple Myeloma; Myeloablative Agonists; Oxides; Survival Rate; Time Factors; Transplantation Conditioning; Transplantation, Autologous

This multicenter, open-label, phase I/II dose escalation study assessed the safety/tolerability and initial efficacy of arsenic trioxide/bortezomib/ascorbic acid (ABC) combination therapy in patients with relapsed/refractory multiple myeloma.. Enrolled in six cohorts, patients were given arsenic trioxide (0.125 or 0.250 mg/kg), bortezomib (0.7, 1.0, or 1.3 mg/m(2)), and a fixed dose of ascorbic acid (1 g) i.v. on days 1, 4, 8, and 11 of a 21-day cycle for a maximum of eight cycles. The primary end point was safety/tolerability of the ABC regimen.. Twenty-two patients (median age, 63 years) were enrolled, having failed a median of 4 (range, 3-9) prior therapies. One occurrence of grade 4 thrombocytopenia was observed. One patient had asymptomatic arrhythmia and withdrew from the study. Objective responses were observed in 6 (27%) patients, including two partial responses and four minor responses. Median progression-free survival was 5 months (95% confidence interval, 2-9 months), and median overall survival had not been reached. The 12-month progression-free survival and overall survival rates were 34% and 74%, respectively. One (minor response) of six patients receiving the lowest dose of bortezomib (0.7 mg/m(2)) and 5 (2 partial responses and 3 minor responses) of 16 patients receiving the higher doses (1.0 or 1.3 mg/m(2)) responded.. The ABC regimen was well tolerated by most patients, and it produced preliminary signs of efficacy with an objective response rate of 27% in this heavily pretreated study population. These findings warrant further clinical evaluation of the ABC combination for treatment of relapsed/refractory multiple myeloma.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Boronic Acids; Bortezomib; Disease-Free Survival; Female; Humans; Male; Middle Aged; Multiple Myeloma; Oxides; Pyrazines; Recurrence; Survival Analysis; Treatment Failure; Treatment Outcome

Single-agent arsenic trioxide has shown promising results in patients with relapsed or refractory multiple myeloma (MM). Because preclinical data suggested greater activity with dexamethasone and ascorbic acid, a phase 2 trial of the combination of arsenic trioxide, dexamethasone, and ascorbic acid in patients with relapsed or refractory MM was conducted.. Twenty patients in whom no more than two previous therapies had failed were enrolled. The mean age was 62 yr, and 55% of the patients had refractory disease. The regimen consisted of 14- or 15-wk cycles, with the first cycle considered induction, followed by one or two consolidation cycles with a reduced steroid schedule and then a maintenance cycle in responding patients.. The overall response rate was 30%, with at least stable disease in 80% of patients. Median progression- free survival was 316 d in all patients and 584 d in those with a response. The regimen was well tolerated, with most adverse events being mild or moderate.. This study showed the clinical efficacy and tolerability of the combination of arsenic trioxide, dexamethasone, and ascorbic acid. Further study is warranted.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Dexamethasone; Disease-Free Survival; Female; Humans; Male; Middle Aged; Multiple Myeloma; Oxides; Recurrence; Vitamins

We assessed the safety and efficacy of melphalan, arsenic trioxide (ATO) and ascorbic acid (AA) (MAC) combination therapy for patients with multiple myeloma (MM) who failed more than two different prior regimens. Patients received melphalan (0.1 mg/kg p.o.), ATO (0.25 mg/kg i.v.) and AA (1 g i.v) on days 1-4 of week 1, ATO and AA twice weekly during weeks 2-5 and no treatment during week 6 of cycle 1; during cycles 2-6, the schedule remained the same except ATO and AA were given twice weekly in week 1. Objective responses occurred in 31 of 65 (48%) patients, including two complete, 15 partial and 14 minor responses. Median progression-free survival and overall survival were 7 and 19 months respectively. Twenty-two patients had elevated serum creatinine levels (SCr) at baseline, and 18 of 22 (82%) showed decreased SCr levels during treatment. Specific grade 3/4 haematological (3%) or cardiac adverse events occurred infrequently. Frequent grade 3/4 non-haematological adverse events included fever/chills (15%), pain (8%) and fatigue (6%). This steroid-free regimen was effective and well tolerated in this heavily pretreated group. These results indicate that the MAC regimen is a new therapeutic option for patients with relapsed or refractory MM.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Creatinine; Female; Humans; Male; Melphalan; Middle Aged; Multiple Myeloma; Oxides; Prospective Studies; Recurrence; Survival Analysis; Treatment Outcome

Arsenic trioxide induces growth inhibition and apoptosis in multiple myeloma cell lines. Reducing glutathione by ascorbic acid may enhance the efficacy of arsenic trioxide. Here we report the results of an international multi-center study of arsenic trioxide in combination with ascorbic acid and dexamethasone as treatment for patients with advanced multiple myeloma.

Topics: Adult; Aged; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Dexamethasone; Drug Therapy, Combination; Follow-Up Studies; Humans; Middle Aged; Multiple Myeloma; Oxides; Recurrence

Topics: Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Disease Progression; Drug Resistance, Neoplasm; Humans; Melphalan; Middle Aged; Multiple Myeloma; Oxides; Prospective Studies; Recurrence; Time Factors; Treatment Outcome

Patients with multiple myeloma (MM) invariably relapse with chemotherapy-resistant disease, underscoring the need for new agents that bypass these resistance mechanisms. We have reported that ascorbic acid (AA) enhances the activity of arsenic trioxide (As(2)0(3)) against drug-resistant MM in vitro by depleting intracellular glutathione (GSH). These data led us to open a National Cancer Institute/Cancer Therapy Evaluation Program-sponsored Phase I/II trial of As(2)0(3) + AA for relapsed/refractory MM. We now present the completed Phase I component of this trial. The primary objective of the trial's Phase I component was to assess whether the addition of AA affected the well-described toxicity profile of As(2)0(3) alone. Correlative studies were undertaken of As(2)0(3) and AA pharmacokinetics, the ability of AA to deplete intracellular GSH in vivo, and the development of arsenic resistance. Six patients with stage IIIA relapsed/refractory myeloma were studied. We found that 0.25 mg/kg/day As(2)O(3) + 1,000 mg/day AA could be given for 25 days (over a 35-day period) without dose-limiting toxicity. One episode of grade 3 hematological toxicity (leukopenia) and no grade 3 nonhematological toxicities (in particular, cardiac) were observed. The coadministration of AA did not alter the pharmacokinetics of As(2)0(3), and elevated AA levels were associated with decreased intracellular GSH. Serial in vitro studies demonstrated continued sensitivity of patient myeloma cells to As(2)0(3) + AA. Two patients (both with thalidomide-refractory disease) had partial responses; four patients had stable disease. In conclusion, we have found that As(2)0(3) + AA has acceptable toxicity and that there is promising evidence of activity in refractory/relapsed myeloma.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Drug Resistance, Neoplasm; Feasibility Studies; Female; Glutathione; Humans; Male; Middle Aged; Multiple Myeloma; Neoplasm Recurrence, Local; Oxides; Salvage Therapy; Treatment Outcome

High-dose chemotherapies to treat multiple myeloma (MM) can be life-threatening due to toxicities to normal cells and there is a need to target only tumor cells and/or lower standard drug dosage without losing efficacy. We show that pharmacologically-dosed ascorbic acid (PAA), in the presence of iron, leads to the formation of highly reactive oxygen species (ROS) resulting in cell death. PAA selectively kills CD138

Topics: Animals; Antineoplastic Agents; Apoptosis; Ascorbic Acid; Calcium-Binding Proteins; Cell Line, Tumor; DNA-Binding Proteins; Drug Therapy, Combination; Humans; Iron; Melphalan; Mice; Mice, Inbred NOD; Microfilament Proteins; Multiple Myeloma; Reactive Oxygen Species; Syndecan-1; Transplantation, Heterologous

Topics: Ascorbic Acid; Humans; Multiple Myeloma

Multiple myeloma is a malignant silent incurable plasma cell disorder. The present study aimed to assessed the activation of the oxidative stress pathway in affected patients.. Advanced oxidation protein products (AOPPs), malondialdehyde (MDA), adenosine deaminase (ADA), total antioxidant capacity (TAC) levels, glutathione, ascorbic acid (vitamin C), α-tocopherol (vitamin E) in addition to related enzymes glutathione peroxidase (GSH-Px), glutathione reductase (GSH-R) and superoxide dismutase (SOD) were analyzed in sixty patients with multiple myeloma before and after one month treatment with induction therapy.. The results of the study showed a significant elevation in AOPPs, MDA, ADA levels in patients with multiple myeloma before and after treatment in comparison to healthy control samples In contrast TAC glutathione, vitamin C and E, and the antioxidant enzymes levels were decreased significantly. On comparing samples of MM patients after treatment, there was significant increase of TAC glutathione, vitamin C and E, and the antioxidant enzymes in parallel with decreasing AOPPs, MDA and ADA levels in comparison with samples of patients before treatment.. The results indicate oxidative stress and DNA damage activity increase in MM and are alleviated in response to therapy.

Topics: Adenosine Deaminase; Advanced Oxidation Protein Products; alpha-Tocopherol; Antioxidants; Ascorbic Acid; Biomarkers; Case-Control Studies; Combined Modality Therapy; Female; Follow-Up Studies; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Humans; Male; Malondialdehyde; Middle Aged; Multiple Myeloma; Prognosis; Superoxide Dismutase; Vitamin E

Topics: Anemia, Hemolytic; Antioxidants; Ascorbic Acid; Cyclophosphamide; Glucosephosphate Dehydrogenase Deficiency; Hemolysis; Humans; Male; Methemoglobinemia; Middle Aged; Multiple Myeloma; Myeloablative Agonists; Treatment Outcome; Tumor Lysis Syndrome; Urate Oxidase

Bortezomib-induced peripheral neuropathy (BIPN) emerges as a disabling adverse effect. As rat models for BIPN have demonstrated damage in nerve Schwann cells, we screened for cytoprotective agents to devise a method of rescuing Schwann cells from the cytotoxic effects of bortezomib without compromising its anti-myeloma effects. Schwann cells underwent macroautophagy along with cytoplasmic inclusion body and vacuole formation, and appeared much less susceptible to bortezomib-induced cytotoxicity than did myeloma cells. Vitamin C or N-acetyl-L-cysteine (NAC) achieved near-complete rescue of Schwann cells treated with bortezomib at 30 nM or less, and these agents in combination are able to cooperatively inhibit the morphological changes and the cytotoxicity in Schwann cells with higher doses of bortezomib. The delayed addition of vitamin C and/or NAC after the exposure to bortezomib alleviated the cytotoxicity in Schwann cells but not myeloma cells. These results suggest that delayed treatment with these agents may be instrumental in prophylaxis of BIPN.

Topics: Acetylcysteine; Animals; Antineoplastic Agents; Antioxidants; Ascorbic Acid; Autophagy; Boronic Acids; Bortezomib; Cell Line; Endoplasmic Reticulum; Free Radical Scavengers; Multiple Myeloma; Neuroprotective Agents; Peripheral Nervous System Diseases; Pyrazines; Rats; Schwann Cells

Earlier studies have shown that ascorbic acid (vitamin C) inhibits bortezomib-induced cytotoxicity against cancer cells in vitro. However, the clinical significance of vitamin C on bortezomib treatment is unclear. In this study, we examined whether daily oral intake of vitamin C inhibits antimultiple myeloma (MM) activities of bortezomib. Vitamin C, at orally achievable concentrations, inhibited in vitro MM cell cytotoxicity of bortezomib and blocked its inhibitory effect on 20S proteasome activity. Specifically, plasma collected from healthy volunteers taking 1 g/day vitamin C reduced bortezomib-induced MM cell death in vitro. This antagonistic effect of vitamin C against proteasome inhibitors is limited to the boronate class of inhibitors (bortezomib and MG262). In vivo activity of this combination treatment was then evaluated using our xenograft model of human MM in SCID (severe combined immune-deficient) mice. Bortezomib (0.1 mg/kg twice a week for 4 weeks) significantly inhibits in vivo MM cell growth, which was blocked by oral vitamin C (40 mg/kg/day). Therefore, our results for the first time show that vitamin C can significantly reduce the activity of bortezomib treatment in vivo; and importantly, suggest that patients receiving treatment with bortezomib should avoid taking vitamin C dietary supplements.

Topics: Animals; Antineoplastic Agents; Antioxidants; Ascorbic Acid; Boronic Acids; Bortezomib; Cell Line, Tumor; Cell Proliferation; Humans; Mice; Multiple Myeloma; Proteasome Inhibitors; Pyrazines

Multiple myeloma (MM), neoplastic disorder, is a B-cell malignancy characterised by the accumulation of clonal population of plasma cells. Reactive oxygen species and other free radicals mediate phenotypic and genotypic changes leading from mutation to neoplasia in all cancers including MM. In the present study, 50 clinically diagnosed patients with MM at stage II of international staging system and 50 healthy controls were included. beta(2) microglobulin levels were estimated by ELISA. The circulating levels of enzymatic antioxidants; superoxide dismutase (SOD), glutathione peroxidase (GPX) were spectrophotometrically estimated using RANDOX kits whereas catalase, malondialdehyde (MDA), vitamin C and E were estimated by standardised protocols using spectrophotometer/fluorometer. The serum beta(2) microglobulin levels were significantly higher (>3 microg/mL) in patients with MM than healthy controls. The estimated levels of SOD, GPX and catalase (enzymatic antioxidants) and vitamin C and E (non-enzymatic antioxidants) were significantly declined in patients whereas MDA levels were elevated as compared with controls. These results suggest that MM is closely associated with oxidative stress and reduced antioxidant capacity and further investigation might provide an insight to understand a putative causal link between oxidative stress and MM disease progression.

Topics: Antioxidants; Ascorbic Acid; beta 2-Microglobulin; Biomarkers; Case-Control Studies; Female; Humans; Male; Malondialdehyde; Middle Aged; Multiple Myeloma; Oxidative Stress; Oxidoreductases; Spectrum Analysis

Topics: Antineoplastic Agents; Antioxidants; Ascorbic Acid; Boronic Acids; Bortezomib; Drug Interactions; Humans; Multiple Myeloma; Pyrazines

Arsenic trioxide (ATO) induces apoptosis of malignant plasma cells through multiple mechanisms, including inhibition of DNA binding by nuclear factor kappa-B, a key player in the development of chemoresistance in multiple myeloma (MM). This activity suggests that ATO may be synergistic when combined with other active antimyeloma drugs. To evaluate this, we examined the antimyeloma effects of ATO alone and in combination with bortezomib, melphalan and ascorbic acid (AA) both in vitro and in vivo using a severe combined immunodeficient (SCID)-hu murine myeloma model. Marked synergistic antimyeloma effects were demonstrated when human MM Los Angeles xenograft IgG lambda light chain (LAGlambda-1) cells were treated in vitro with ATO and any one of these agents. SCID mice bearing human MM LAGlambda-1 tumours were treated with single-agent ATO, bortezomib, melphalan, or AA, or combinations of ATO with either bortezomib or melphalan and AA. Animals treated with any of these drugs alone showed tumour growth and increases in paraprotein levels similar to control mice, whereas animals treated with ATO-containing combinations showed markedly suppressed tumour growth and significantly reduced serum paraprotein levels. These in vitro and in vivo results suggest that addition of ATO to other antimyeloma agents may result in improved outcomes for patients with relapsed or refractory MM.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Boronic Acids; Bortezomib; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin G; Melphalan; Mice; Mice, SCID; Multiple Myeloma; Oxides; Pyrazines; Xenograft Model Antitumor Assays

Arsenic trioxide (As2O3, Trisenox) is used to treat patients with refractory or relapsed acute promyelocytic leukemia (APL). Its ability to induce apoptosis in various malignant cell lines has made it a potential treatment agent for other malignancies and many clinical trials are currently in progress to evaluate its clinical usefulness for multiple myeloma and glioblastoma cancer. In the present study, we investigated the metabolism of As2O3 regarding its cellular biotransformation and interaction with metallothionein (MT) as a possible protective responses of cells to arsenic-induced cytotoxicity. The study was performed on two types of cell treated with As2O3: (1) human astrocytoma (glioblastoma) cell line U87MG treated with 0.6 microM arsenic for 0, 3, 12, 24, and 48 h or 12 microM arsenic for 3, 6, 12, 24, and 48 h and (2) bone marrow cells (BM) from two patients with multiple myeloma (MM) treated with 7 microM arsenic for 0, 43, and 67 h. Cotreatment with vitamin C (1 mg/mL) was tested in longer exposure of MM BM cells. Traces of methylation products (mainly monomethylarsenic acid) were detected in cell lysates of both cell types and in pellets of U87 MG cells, although we found problems with column-sample interactions in cases where methanol pretreatment of the sample was not used. Pentavalent inorganic arsenic (AsV) was identified in both cell types, and up to 80% of total As in MM bone marrow cell lysates was present as AsV. Such an occurrence (generation) of pentavalent arsenic after As2O3 treatment demonstrates the presence of biological oxidation of trivalent arsenic, which could represent an additional protective mechanism of the cell. Vitamin C decreased As cell content and increased the percentage of pentavalent inorganic arsenic (in the growth medium and cells). The presence of metallothionein (MT) and its response to arsenic treatment was checked in all U87 MG cells, in the control, and in one exposed sample of MM BM cells. During 48 h exposure to 0.6 or 12 muM arsenic MTI/II levels increased in U87 MG cells, but with variable Zn levels, increased Cu levels, and As binding observed in traces only. Involvement of the MT-III isoform was negligible. In contrast, 43 h exposure to 7 microMarsenic did not increase MT content in multiple myeloma cells, and the levels even decreased with respect to the control. To evaluate the importance of the observed processes, MTs in U87 and AsIII-AsV conversion in MM BM cells, which could represent a resista

Topics: Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Astrocytoma; Biotransformation; Bone Marrow Cells; Cell Line, Tumor; Chromatography, Ion Exchange; Humans; Models, Chemical; Multiple Myeloma; Oxides; Reactive Oxygen Species; Time Factors

Topics: Aged; Antineoplastic Agents, Alkylating; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Female; Humans; Male; Melphalan; Middle Aged; Multiple Myeloma; Oxides; Recurrence; Treatment Outcome

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by slow-growing plasma cells in the bone marrow (BM). Patients with MM typically respond to initial chemotherapies; however, essentially all progress to a chemoresistant state. Factors that contribute to the chemorefractory phenotype include modulation of free radical scavenging, increased expression of drug efflux pumps, and changes in gene expression that allow escape from apoptotic signaling. Recent data indicate that arsenic trioxide (As(2)O(3)) induces remission of refractory acute promyelocytic leukemia and apoptosis of cell lines overexpressing Bcl-2 family members; therefore, it was hypothesized that chemorefractory MM cells would be sensitive to As(2)O(3). As(2)O(3) induced apoptosis in 4 human MM cell lines: 8226/S, 8226/Dox40, U266, and U266/Bcl-x(L). The addition of interleukin-6 had no effect on cell death. Glutathione (GSH) has been implicated as an inhibitor of As(2)O(3)-induced cell death either through conjugating As(2)O(3) or by sequestering reactive oxygen induced by As(2)O(3). Consistent with this possibility, increasing GSH levels with N-acetylcysteine attenuated As(2)O(3) cytotoxicity. Decreases in GSH have been associated with ascorbic acid (AA) metabolism. Clinically relevant doses of AA decreased GSH levels and potentiated As(2)O(3)-mediated cell death of all 4 MM cell lines. Similar results were obtained in freshly isolated human MM cells. In contrast, normal BM cells displayed little sensitivity to As(2)O(3) alone or in combination with AA. Together, these data suggest that As(2)O(3) and AA may be effective antineoplastic agents in refractory MM and that AA might be a useful adjuvant in GSH-sensitive therapies. (Blood. 2001;98:805-813)

Topics: Acetylcysteine; Antineoplastic Agents; Antioxidants; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Cell Death; Drug Synergism; Glutathione; Humans; Hydrogen Peroxide; Multiple Myeloma; Oxides; Plasma Cells; Superoxides; Tumor Cells, Cultured

There is growing evidence that proteins are early targets of reactive oxygen species, and that the altered proteins can in turn damage other biomolecules. In this study, we measured the effects of proteins on the oxidation of liposome phospholipid membranes, and the formation of protein hydroperoxides in serum and in cultured cells exposed to radiation-generated hydroxyl free radicals. Lysozyme, which did not affect liposome stability, gave 50% protection when present at 0.3 mg/ml, and virtually completely prevented lipid oxidation at 10 mg/ml. When human blood serum was irradiated, lipids were oxidized only after the destruction of ascorbate. In contrast, peroxidation of proteins proceeded immediately. Protein hydroperoxides were also generated without a lag period in hybrid mouse myeloma cells, while at the same time no lipid peroxides formed. These results are consistent with the theory that, under physiological conditions, lipid membranes are likely to be effectively protected from randomly-generated hydroxyl radicals by proteins, and that protein peroxyl radicals and hydroperoxides may constitute an important hazard to biological systems under oxidative stress.

Topics: Animals; Ascorbic Acid; Dose-Response Relationship, Drug; Humans; Hydrogen Peroxide; Kinetics; Lipid Peroxidation; Lipids; Liposomes; Mice; Models, Chemical; Multiple Myeloma; Muramidase; Oxidative Stress; Oxygen; Proteins; Reactive Oxygen Species; Time Factors; Tumor Cells, Cultured

L-Ascorbic acid (LAA) was shown to modulate the in vitro growth of colonies of human and mouse myeloma progenitor-stem cells through use of a unique cell-culture assay. LAA was also shown to modulate the in vitro growth of leukemic colony-forming cells (L-CFC) from bone marrow of patients with acute myelocytic leukemia. LAA enhanced the growth of L-CFC in 35% of patients and suppressed the growth of L-CFC in 15% of patients. The minimum effective concentration was 0.03 mmol/L. The modulating effect is specific to LAA because other redox compounds are without effect. From the cell kinetic standpoint, the LAA effect is cytostatic rather than cytocidal. Similar LAA effects have prognostic value in patients with myelodysplastic syndromes (MDS), with LAA-sensitive patients displaying shorter survival than LAA-insensitive patients. MDS appears to be the ideal disease for clinical trials involving in vivo LAA manipulation to control the disease process.

Topics: Adult; Ascorbic Acid; Bone Marrow; Cell Division; Humans; Leukemia; Multiple Myeloma; Myelodysplastic Syndromes; Osmolar Concentration; Preleukemia; Prognosis; Stem Cells

The ability to clone primary tumors in soft agar has proven useful in the study of the kinetics and biological properties of tumor stem cells. We report the development of an in vitro assay which permits formation of colonies of human monoclonal plasma cells in soft agar. Colony growth has been observed from bone marrow aspirates from 75% of the 70 patients with multiple myeloma or related monoclonal disorders studied. Growth was induced with either 0.02 ml of human type O erythrocytes or 0.25 ml of medium conditioned by the adherent spleen cells of mineral oil-primed BALB/c mice. 5-500 colonies appeared after 2-3 wk in culture yielding a plating efficiency of 0.001-0.1%. The number of myeloma colonies was proportional to the number of cells plated between concentrations of 10(5)-10(6) and back-extrapolated through zero, suggesting that colonies were clones derived from single myeloma stem cells. Morphological, histochemical, and functional criteria showed the colonies to consist of immature plasmablasts and mature plasma cells. 60-80% of cells picked from colonies contained intracytoplasmic monoclonal immunoglobulin. Colony growth was most easily achieved from the bone marrow cells of untreated patients or those in relapse. Only 50% of bone marrow samples from patients in remission were successfully cultured. Tritiated thymidine suicide studies provided evidence that for most myeloma patients, a very high proportion of myeloma colony-forming cells was actively in transit through the cell cycle. Velocity sedimentation at 1 g showed myeloma stem cells sedimented in a broad band with a peak at 13 mm/h. Antibody to granulocyte colony-stimulating factor did not reduce the number or size of the colonies. Increased numbers of myeloma colonies were seen when the marrow was depleted of colony-stimulating factor elaborating adherent cells before plating. This bioassay should prove useful in studying the in vitro biological behavior of certain bone marrow-derived (B)-cell neoplasia. In addition, systematic and predictive studies of anticancer drug effects on myeloma stem cells should now be feasible.

Topics: Antigen-Antibody Reactions; Ascorbic Acid; Cell Division; Cells, Cultured; Colony-Stimulating Factors; Culture Media; Hematopoietic Stem Cells; Humans; Immunoglobulin G; Multiple Myeloma; Phagocytosis; Plasma Cells; Ultracentrifugation

Topics: Agglutination Tests; Ascorbic Acid; Candida; Candidiasis; Humans; Immunodiffusion; In Vitro Techniques; Iron; Leukemia, Lymphoid; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Lymphoma; Multiple Myeloma; Polycythemia Vera; Precipitin Tests; Transferrin