Statin and Bisphosphonate Induce Starvation in Fast-Growing Cancer Cell Lines.
ABSTRACT: Statins and bisphosphonates are increasingly recognized as anti-cancer drugs, especially because of their cholesterol-lowering properties. However, these drugs act differently on various types of cancers. Thus, the aim of this study was to compare the effects of statins and bisphosphonates on the metabolism (NADP?/NADPH-relation) of highly proliferative tumor cell lines from different origins (PC-3 prostate carcinoma, MDA-MB-231 breast cancer, U-2 OS osteosarcoma) versus cells with a slower proliferation rate like MG-63 osteosarcoma cells. Global gene expression analysis revealed that after 6 days of treatment with pharmacologic doses of the statin simvastatin and of the bisphosphonate ibandronate, simvastatin regulated more than twice as many genes as ibandronate, including many genes associated with cell cycle progression. Upregulation of starvation-markers and a reduction of metabolism and associated NADPH production, an increase in autophagy, and a concomitant downregulation of H3K27 methylation was most significant in the fast-growing cancer cell lines. This study provides possible explanations for clinical observations indicating a higher sensitivity of rapidly proliferating tumors to statins and bisphosphonates.
Project description:Nuclear receptors (NRs) are key regulators of gene expression and physiology. Nearly half of all human NRs lack endogenous ligands including estrogen-related receptor ? (ERR?). ERR? has important roles in cancer, metabolism, and skeletal homeostasis. Affinity chromatography of tissue lipidomes with the ERR? ligand-binding domain (LBD) and subsequent transcriptional assays identified cholesterol as an endogenous ERR? agonist. Perturbation of cholesterol biosynthesis or inhibition of ERR? revealed the interdependence of cholesterol and ERR?. In bone, the effects of cholesterol, statin, and bisphosphonate on osteoclastogenesis require ERR?; and consequently, cholesterol-induced bone loss or bisphosphonate osteoprotection is lost in ERR? knockout mice. Furthermore, statin induction of muscle toxicity and cholesterol suppression of macrophage cytokine secretion are impaired by loss or inhibition of ERR?. These findings reveal a key step in ERR? regulation and explain the actions of two highly prescribed drugs, statins and bisphosphonates.
Project description:Bisphosphonates have benefits in breast cancer and multiple myeloma patients and have been used with adoptive immunotherapy with ?? T cells expressing V?2?V?2 TCRs. Although treatment with ?? T cells is safe, it has shown limited efficacy. Present bisphosphonates stimulate ?? T cells but were designed to inhibit bone resorption rather than treating cancer and have limited oral absorption, tumor cell entry, and cause bone side effects. The development of phosphate and phosphonate nucleotide prodrugs has led to important drugs for hepatitis C and HIV. Using a similar approach, we synthesized bisphosphonate prodrugs and found that they efficiently limit tumor cell growth. Pivoxil bisphosphonate esters enter cells where esterases convert them to their active acids. The bisphosphonate esters stimulated ?? T cells to secrete TNF-? in response to a variety of tumor cells more efficiently than their corresponding acids. The most active compound, tetrakis-pivaloyloxymethyl 2-(thiazole-2-ylamino)ethylidene-1,1- bisphosphonate (7), specifically expanded ?? T cells and stimulated them to secrete interferon-? and kill tumor cells. In preclinical studies, combination therapy with compound 7 and ?? T cells prolonged survival of mice inoculated with either human bladder cancer or fibrosarcoma cells. Therefore, bisphosphonate prodrugs could enhance the effectiveness of adoptive cancer immunotherapy with ?? T cells.
Project description:Although intravenous (i.v.) bisphosphonates are the standard of care for metastatic bone disease, they are less than ideal for many patients due to infusion-related adverse events (AEs), an increased risk of renal toxicity and the inconvenience of regular hospital visits. The use of oral bisphosphonate therapy is limited by concerns over efficacy and gastrointestinal (GI) side effects. There remains a clinical need for an oral bisphosphonate that offers equivalent efficacy to i.v. bisphosphonates, good tolerability and dosing convenience. Oral ibandronate, a highly potent, third-generation aminobisphosphonate, has been evaluated in phase III clinical trials of patients with bone metastases from breast cancer. In two pooled phase III studies, patients with breast cancer and bone metastases were randomised to receive oral ibandronate 50 mg (n=287) or placebo (n=277) once daily for up to 96 weeks. The primary end point was the skeletal morbidity period rate (SMPR), defined as the number of 12-week periods with new skeletal complications. Multivariate Poisson's regression analysis was used to assess the relative risk of skeletal-related events in each treatment group during the study period. Oral ibandronate 50 mg significantly reduced the mean SMPR compared with placebo (0.95 vs 1.18, P=0.004). There was a significant reduction in the mean number of events requiring radiotherapy (0.73 vs 0.98, P<0.001) and events requiring surgery (0.47 vs 0.53, P=0.037). Poisson's regression analysis confirmed that oral ibandronate significantly reduced the risk of a skeletal event compared with placebo (hazard ratio 0.62, 95% CI=0.48, 0.79; P=0.0001). The incidence of mild treatment-related upper GI AEs was slightly higher in the oral ibandronate 50 mg group compared with placebo, but very few serious drug-related AEs were reported. Oral ibandronate 50 mg is an effective, well-tolerated and convenient treatment for the prevention of skeletal complications of metastatic bone disease.
Project description:Bisphosphonates are the gold standard for preventing skeletal-related events in patients with bone-metastatic cancer and have been investigated for reducing cancer treatment-induced bone loss. Evidence suggests bisphosphonates also offer anticancer benefits in adjuvant and advanced cancer settings. We conducted a retrospective analysis of data from a single-center, unselected cohort of women with early breast cancer (N=1646: 962 received adjuvant bisphosphonates, 684 did not) to assess the impact of bisphosphonates on disease-free and overall survival. The bisphosphonate group comprised all women who started bisphosphonate treatment within 1 year of breast cancer diagnosis and received ?3 months of bisphosphonate treatment (zoledronic acid, clodronate, ibandronate, or alendronate; majority received zoledronic acid). Disease-free survival was defined as the time from breast cancer diagnosis until first disease recurrence or death. Treatment groups were balanced for cancer stage, hormone receptor expression, and human epidermal growth factor receptor-2 expression. Patients in the no-bisphosphonate group were more likely to be ?75 years of age, node-negative, and have histologic grade 3 tumors. In patients treated with adjuvant bisphosphonates, disease-free survival was significantly longer than in those who did not receive bisphosphonates (P=0.0017). Both disease-free and overall survival were significantly longer in patients with hormone receptor-positive disease irrespective of lymph node status (disease-free survival: P=0.0038; overall survival: P<0.0026). No significant disease-free survival difference was detected in patients with hormone receptor-negative disease. This large, retrospective study demonstrates a significant survival benefit with adjuvant bisphosphonates in patients with early breast cancer, particularly in patients with node-positive and hormone receptor-positive disease.
Project description:Anti-resorptive bisphosphonates (BP) are used for the treatment of osteoporosis and bone metastases. Clinical studies indicated a benefit in survival and tumor relapse in subpopulations of breast cancer patients receiving zoledronic acid, thus stimulating the debate about its anti-tumor activity. Amino-bisphosphonates in nM concentrations inhibit farnesyl pyrophosphate synthase leading to accumulation of isopentenyl pyrophosphate (IPP) and the ATP/pyrophosphate adduct ApppI, which induces apoptosis in osteoclasts. For anti-tumor effects ?M concentrations are needed and a sensitizer for bisphosphonate effects would be beneficial in clinical anti-tumor applications. We hypothesized that enhancing intracellular pyrophosphate accumulation via inhibition of probenecid-sensitive channels and transporters would sensitize tumor cells for bisphosphonates anti-tumor efficacy.MDA-MB-231, T47D and MCF-7 breast cancer cells were treated with BP (zoledronic acid, risedronate, ibandronate, alendronate) and the pyrophosphate channel inhibitors probenecid and novobiocin. We determined cell viability and caspase 3/7 activity (apoptosis), accumulation of IPP and ApppI, expression of ANKH, PANX1, ABCC1, SLC22A11, and the zoledronic acid target gene and tumor-suppressor KLF2.Treatment of MDA-MB-231 with BP induced caspase 3/7 activity, with zoledronic acid being the most effective. In MCF-7 and T47D either BP markedly suppressed cell viability with only minor effects on apoptosis. Co-treatment with probenecid enhanced BP effects on cell viability, IPP/ApppI accumulation as measurable in MCF-7 and T47D cells, caspase 3/7 activity and target gene expression. Novobiocin co-treatment of MDA-MB-231 yielded identical results on viability and apoptosis compared to probenecid, rendering SLC22A family members as candidate modulators of BP effects, whereas no such evidence was found for ANKH, ABCC1 and PANX1.In summary, we demonstrate effects of various bisphosphonates on caspase 3/7 activity, cell viability and expression of tumor suppressor genes in breast cancer cells. Blocking probenecid and novobiocin-sensitive channels and transporters enhances BP anti-tumor effects and renders SLC22A family members as good candidates as BP modulators. Further studies will have to unravel if treatment with such BP-sensitizers translates into preclinical and clinical efficacy.
Project description:BACKGROUND:Recent evidence from in vitro and in vivo studies indicates that bisphosphonates may promote osteoblastic bone formation and potently inhibit osteoclast activity. However, little is known about the potential effect of bisphosphonates on the recruitment of osteoblastic precursors from patient-derived bone marrow stromal cells due to difficulties in accessing human bone marrow from healthy and disease subjects. METHODS:In this study, we evaluated the potential of using FDA-approved and clinically utilized bisphosphonates such as alendronate, ibandronate, and zoledronate to enhance the development of bone forming osteoblasts from osteoporosis patient- and healthy-person derived hBMSCs (op-MSCs and hp-MSCs, respectively). hBMSCs were obtained from postmenopausal women without endocrine diseases or receiving hormone replacement therapy. Cells were treated with or without a bisphosphonate (alendronate, ibandronate, and zoledronate) and analyzed over 21 days of culture. RESULTS:hBMSC from osteoporosis-patient with bisphosphonates treatment demonstrated a significant increase in Alizarin red staining after 7 days compared to that from healthy-person. Calcium contents and alkaline phosphatase (ALP) enzyme activity also demonstrated an increased propensity in hMSCs from osteoporosis-patient compared to those from healthy-person, although there were inter-individual variations. Gene expression levels varied among different donors. There were no significant differences in the effect on the osteoblastic differentiation of hBMSCs among alendronate, ibandronate, and zoledronate. Statistical significance in the osteoblastic differentiation of hBMSCs between the positive control group cultured in osteogenic medium alone and groups cultured in osteogenic medium supplemented with bisphosphonate was not shown either. These results might be due to various cell types of hBMSCs from individual clinical patients and concentrations of bisphosphonate used. CONCLUSION:Our study using a clinically relevant in vitro model suggests that bisphosphonate treatment is more effective for patients with osteoporosis than its preventive effect for healthy person. In addition, patient-specific responses to bisphosphonates should be considered rather than bisphosphonate type prior to prescription. Further investigations are needed to determine how bisphosphonates influence hBMSCs function to mediate bone quality and turnover in osteoporotic patients. Such studies can generate novel approaches to treat age-related osteoporotic bone loss.
Project description:Eighteen different bisphosphonates, including four clinically used bisphosphonate acids and their phosphoesters, were studied to evaluate how the bisphosphonate structure affects binding to bone. Bisphosphonates with weak bone affinity, such as clodronate, could not bind to hydroxyapatite after the addition of one ester group. Medronate retained its ability to bind after the addition of one ester group, and hydroxy-bisphosphonates could bind even after the addition of two ester groups. Thus, several bisphosphonate esters are clearly bone binding compounds. The following conclusions about bisphosphonate binding emerge: (1) a hydroxyl group in the geminal carbon takes part in the binding process and increases the bisphosphonate's ability to bind to bone; (2) the bisphosphonate's ability to bind decreases when the amount of ester groups increases; and (3) the location of the ester groups affects the bisphosphonate's binding ability.
Project description:Nitrogen-containing bisphosphonates are the elected drugs for the treatment of diseases in which excessive bone resorption occurs, for example, osteoporosis and cancer-induced bone diseases. The only known target of nitrogen-containing bisphosphonates is farnesyl pyrophosphate synthase, which ensures prenylation of prosurvival proteins, such as Ras. However, it is likely that the action of nitrogen-containing bisphosphonates involves additional unknown mechanisms. To identify novel targets of nitrogen-containing bisphosphonates, we used a genome-wide high-throughput screening in which 5,936 Saccharomyces cerevisiae heterozygote barcoded mutants were grown competitively in the presence of sub-lethal doses of three nitrogen-containing bisphosphonates (risedronate, alendronate and ibandronate). Strains carrying deletions in genes encoding potential drug targets show a variation of the intensity of their corresponding barcodes on the hybridization array over the time.With this approach, we identified novel targets of nitrogen-containing bisphosphonates, such as tubulin cofactor B and ASK/DBF4 (Activator of S-phase kinase). The up-regulation of tubulin cofactor B may explain some previously unknown effects of nitrogen-containing bisphosphonates on microtubule dynamics and organization. As nitrogen-containing bisphosphonates induce extensive DNA damage, we also document the role of DBF4 as a key player in nitrogen-containing bisphosphonate-induced cytotoxicity, thus explaining the effects on the cell-cycle.The dataset obtained from the yeast screen was validated in a mammalian system, allowing the discovery of new biological processes involved in the cellular response to nitrogen-containing bisphosphonates and opening up opportunities for development of new anticancer drugs.
Project description:Osteoporosis related fractures contribute to morbidity and mortality in U.S. patients, placing a heavy financial burden on society. Randomized clinical trials involving over 30,000 subjects have established bisphosphonates' efficacy in reducing the incidence of fragility fractures. However, as bisphosphonates are retained for years in the skeleton, reports of adverse events from prolonged use are surfacing in the literature, namely, esophageal cancer, atrial fibrillation, osteonecrosis of the jaw, and atypical fracture development. The concept of a drug holiday has been proposed to potentially reduce incidence of these adverse events. This review will highlight the benefits and risks of bisphosphonate therapy and discuss the extension data available from the bisphosphonate trials. As randomized clinical trial evidence is not yet available on who may qualify for drug holiday, this review will provide suggestions for clinicians on identification of possible candidates and monitoring during a bisphosphonate drug holiday.
Project description:Recent clinical trials have shown that bisphosphonate drugs improve breast cancer patient survival independent of their antiresorptive effects on the skeleton. However, because bisphosphonates bind rapidly to bone mineral, the exact mechanisms of their antitumor action, particularly on cells outside of bone, remain unknown. Here, we used real-time intravital two-photon microscopy to show extensive leakage of fluorescent bisphosphonate from the vasculature in 4T1 mouse mammary tumors, where it initially binds to areas of small, granular microcalcifications that are engulfed by tumor-associated macrophages (TAM), but not tumor cells. Importantly, we also observed uptake of radiolabeled bisphosphonate in the primary breast tumor of a patient and showed the resected tumor to be infiltrated with TAMs and to contain similar granular microcalcifications. These data represent the first compelling in vivo evidence that bisphosphonates can target cells in tumors outside the skeleton and that their antitumor activity is likely to be mediated via TAMs.Bisphosphonates are assumed to act solely in bone. However, mouse models and clinical trials show that they have surprising antitumor effects outside bone. We provide unequivocal evidence that bisphosphonates target TAMs, but not tumor cells, to exert their extraskeletal effects, offering a rationale for use in patients with early disease.