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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The evolution of bisphosphonates over the past 30 years has led to the development of nitrogen-containing bisphosphonates with ever-increasing potency. Recent studies have begun to shed light on the unique mechanism of action and pharmacologic properties of these compounds. On the basis of in vitro studies and animal models of osteoclast-mediated bone resorption, zoledronic acid is the most potent bisphosphonate among a large number of compounds tested, including pamidronate and most other commercially available bisphosphonates. Zoledronic acid maintains bone mass in estrogen-deficient animals without adversely affecting bone mineralization. Moreover, the high potency of zoledronic acid translates into dramatic suppression of bone resorption markers at very low doses in patients with bone metastases, and zoledronic acid has shown efficacy across a broad range of tumor types. Preclinical studies have also shown the potential of bisphosphonates to inhibit tumor cell growth and colonization of the bone and to reduce skeletal tumor burden in animal models. A variety of mechanisms have been proposed to explain these observations and continue to be investigated in animal models. Studies are ongoing to determine if the antitumor potential of bisphosphonates can be exploited in the clinical setting.
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PMID:Preclinical pharmacology of zoledronic acid. 1258 89

Multiple myeloma is characterized by the growth of plasma cells in the bone marrow and the development of osteolytic bone disease. Myeloma cells are found closely associated with bone, and targeting this environment may therefore affect both the bone disease and the growth of myeloma cells. We have investigated the effect of the potent bisphosphonate, zoledronic acid, on the development of bone disease, tumor burden, and disease-free survival in the 5T2MM model of myeloma. 5T2MM murine myeloma cells were injected intravenously into C57BL/KaLwRij mice. After 8 weeks, all animals had a paraprotein. Animals were treated with zoledronic acid (120 microg/kg, subcutaneously, twice weekly) or vehicle, from the time of tumor cell injection or from paraprotein detection for 12 or 4 weeks, respectively. All animals injected with tumor cells developed osteolytic lesions, a decrease in cancellous bone volume, an increase in osteoclast perimeter, and a decrease in bone mineral density. Zoledronic acid prevented the formation of lesions, prevented cancellous bone loss and loss of bone mineral density, and reduced osteoclast perimeter. Zoledronic acid also decreased paraprotein concentration, decreased tumor burden, and reduced angiogenesis. In separate experiments, Kaplan-Meier analysis demonstrated a significant increase in survival after treatment with zoledronic acid when compared with control (47 vs. 35 days). A single dose of zoledronic acid was also shown to be effective in preventing the development of osteolytic bone disease. These data show that zoledronic acid is able to prevent the development of osteolytic bone disease, decrease tumor burden in bone, and increase survival in a model of established myeloma.
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PMID:Zoledronic acid treatment of 5T2MM-bearing mice inhibits the development of myeloma bone disease: evidence for decreased osteolysis, tumor burden and angiogenesis, and increased survival. 1261 33

Less than 25 years ago, tumor-induced hypercalcemia was often a lethal complication of cancer. Nowadays, it can be successfully and easily treated in at least 90% of the cases by rehydration and potent antiosteoclastic bisphosphonates. The standard therapy consists of the administration of 90 mg of pamidronate (Aredia Dry Powder) or more recently, 4 mg of zoledronic acid (Zometa)], which is even more efficient, at least in patients without bone metastases. Recurrent hypercalcemia is nevertheless difficult to control and antibodies against parathyroid-hormone-related protein may prove to be a useful treatment.
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PMID:Treatment of tumor-induced hypercalcemia: a solved problem? 1272 83

Bisphosphonates are potent inhibitors of osteoclast function widely used to treat conditions of excessive bone resorption, including tumor bone metastases. Recent evidence indicates that bisphosphonates have direct cytotoxic activity on tumor cells and suppress angiogenesis, but the associated molecular events have not been fully characterized. In this study we investigated the effects of zoledronate, a nitrogen-containing bisphosphonate, and clodronate, a non-nitrogen-containing bisphosphonate, on human umbilical vein endothelial cell (HUVEC) adhesion, migration, and survival, three events essential for angiogenesis. Zoledronate inhibited HUVEC adhesion mediated by integrin alphaVbeta3, but not alpha5beta1, blocked migration and disrupted established focal adhesions and actin stress fibers without modifying cell surface integrin expression level or affinity. Zoledronate treatment slightly decreased HUVEC viability and strongly enhanced tumor necrosis factor (TNF)-induced cell death. HUVEC treated with zoledronate and TNF died without evidence of enhanced annexin-V binding, chromatin condensation, or nuclear fragmentation and caspase dependence. Zoledronate inhibited sustained phosphorylation of focal adhesion kinase (FAK) and in combination with TNF, with and without interferon (IFN) gamma, of protein kinase B (PKB/Akt). Constitutive active PKB/Akt protected HUVEC from death induced by zoledronate and TNF/IFNgamma. Phosphorylation of c-Src and activation of NF-kappaB were not affected by zoledronate. Clodronate had no effect on HUVEC adhesion, migration, and survival nor did it enhanced TNF cytotoxicity. Taken together these data demonstrate that zoledronate sensitizes endothelial cells to TNF-induced, caspase-independent programmed cell death and point to the FAK-PKB/Akt pathway as a novel zoledronate target. These results have potential implications to the clinical use of zoledronate as an anti-angiogenic or anti-cancer agent.
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PMID:Zoledronate sensitizes endothelial cells to tumor necrosis factor-induced programmed cell death: evidence for the suppression of sustained activation of focal adhesion kinase and protein kinase B/Akt. 1293 98

Many advanced cancers, particularly breast cancer and prostate cancer, metastasize to the bone, resulting in painful lesions and skeletal complications. Intravenous bisphosphonate therapy is an important component of palliative care for patients with bone metastases, and pamidronate has been the standard of care for patients with breast cancer and multiple myeloma since 1996. However, zoledronic acid is the first bisphosphonate shown to significantly reduce skeletal morbidity in patients with a wide range of primary tumor types. Zoledronic acid has demonstrated efficacy in the management of hypercalcemia and metastatic bone disease. In phase III studies involving more than 3000 patients with multiple myeloma, breast cancer, prostate cancer, lung cancer, and other cancers, 4 mg zoledronic acid demonstrated consistent efficacy across a range of clinical end-points, and was safe and well tolerated when infused over 15 min. Based on these studies, zoledronic acid appears to be active in patients with bone metastases irrespective of tumor type, and should be considered as the standard of care for the treatment of bone metastases.
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PMID:Proven efficacy of zoledronic acid in the treatment of bone metastases in patients with breast cancer and other malignancies. 1465 40

Bone is a favorable microenvironment for tumor cell colonization because of abundant growth factors released during active bone resorption. Bisphosphonates can dramatically affect the ability of tumor cells to grow in bone by inhibiting osteoclast-mediated bone resorption and by depriving tumors of growth-promoting signals. Moreover, bisphosphonates have direct anti-tumor effects in vitro via induction of apoptosis. Zoledronic acid is a nitrogen-containing bisphosphonate that has demonstrated potent anti-tumor activity in vitro and in vivo. In vitro studies have provided important clues as to the molecular mechanisms by which zoledronic acid induces apoptosis of human breast cancer cell lines. Studies in multiple myeloma and breast cancer models have shed further light on the possible mechanisms underlying the in vivo anti-tumor effects of zoledronic acid. These studies have led to the development of novel strategies to target specific molecular pathways involved in osteoclast maturation and activity, tumor cell metastasis, and tumor growth and survival. The clinical application of these strategies may ultimately prevent bone metastasis.
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PMID:The anti-tumor potential of zoledronic acid. 1465 41

Various primary malignancies develop bone metastases, and the resultant skeletal complications cause significant morbidity/mortality in advanced cancer patients. Bone lesions associated with metastases are traditionally classified radiologically as either osteolytic or osteoblastic, and both types of lesions are associated with elevated levels of specific bone resorption markers. Some common aspects in the pathophysiology of bone lesions have prompted speculation that treatments for osteolytic metastases might also be effective for predominantly osteoblastic metastases, such as in prostate cancer. Potent osteoclast activity inhibitors, bisphosphonates have been successful in the treatment of osteolytic tumor bone disease. Zoledronic acid is the first bisphosphonate shown to have a direct clinical benefit in the treatment of osteoblastic bone metastases, reducing the number and rate of skeletal events in prostate cancer patients with metastatic bone disease. Moreover, the shorter, more convenient infusion time and similar safety profile of 4 mg zoledronic acid compared with 90 mg pamidronate presently make zoledronic acid the preferred therapy for treatment of bone metastases in patients with all types of advanced malignancy.
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PMID:Rationale for the use of bisphosphonates in osteoblastic and osteolytic bone lesions. 1465 42

Zoledronic acid (ZOL), a nitrogen-containing bisphosphonate, exerts anti-tumor effects by inhibiting the prenylation of small GTPases. We have also reported that ZOL shows an anti-leukemic effect by inducing apoptosis throughout the S phase to the G(2) / M boundary. Here, we studied the effects of ZOL on various cell cycle regulators, including p53, cyclin-dependent kinases (CDKs), CDK inhibitors and cyclins, using BV173 leukemia and HCT116 colorectal carcinoma cell lines, harboring wild-type (wt-) p53. ZOL induced the accumulation of neither p53 nor p21(WAF1/CIP1) during the execution of apoptosis in BV173 cells. Therefore, we investigated the dependence of ZOL-induced apoptosis on intact p53 by using wt-p53 HCT116 and a p53-degraded HCT116 subline, and observed no significant difference. p57(KIP2) was upregulated by ZOL in BV173 cells, but not in HCT116 cells. Flow cytometric analyses showed that ZOL also impaired the cell cycle-dependent expression patterns of cyclins A, B and D3 in BV173. In conclusion, the p53-independent anti-tumor activities of ZOL suggest that it may be an attractive agent for treating cancers, including those with chemoresistance resulting from the loss of p53 function. ZOL also affected the coordinate expression patterns of several cell cycle regulators during the execution of anti-tumor activity.
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PMID:p53-independent anti-tumor effects of the nitrogen-containing bisphosphonate zoledronic acid. 1496 71

Giant cell tumour of bone (GCT) is an aggressive primary neoplasm that results in the production of osteolytic lesions. Stromal cells, which form the main neoplastic component of this tumor, regulate the formation of osleoclast-like giant cells that are ultimately responsible for bone destruction. Bisphosphonates prevent bone resorption by inhibiting osteoclast activity and promoting osteoclast apoptosis, and they have been known to induce apoptosis of primary neoplastic cells such as those in breast and prostate cancers. We hypothesized that in bisphosphonates may induce apoptosis not only in osteoclast-like giant cells but also in neoplastic stromal cells of GCT both in vitro and in vivo. Twelve patients with GCT were treated with weekly injections of pamidronate for a period of 6 weeks prior to surgery. GCT specimens were collected at the time of biopsy and during definitive surgery. TUNEL assay was used to evaluate apoptotic DNA fragmentation in cells. In addition, twelve GCT primary cultures from these patients were treated with zoledronate, pamidronate, or alendronate for 48 hours at different doses (3, 30, or 150 microM) and subjected to apoptosis assay by flow cytometry following fluorescent Annexin-V labeling. The results showed that pamidronate significantly induced apoptosis in both osteoclast-like giant cells and stromal tumor cells, in vivo. All three bisphosphonates caused substantial apoptosis of stromal tumor cells in cultures. Zoledronate was the most potent reagent, resulting in an average cell death of 27.41% at 150 microM, followed by pamidronate (22.23%) and alendronate (15.3%). Our observations suggest that these drugs may be considered as potential adjuvants in the treatment of GCT.
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PMID:Bisphosphonates induce apoptosis of stromal tumor cells in giant cell tumor of bone. 1503 71

Giant cell tumor of bone is an aggressive tumor characterized by extensive bone destruction and high recurrence rates. This tumor consists of stromal cells and hematopoietic cells that interact in an autocrine manner to produce tumoral osteoclastogenesis and bone resorption. This autocrine regulation may be disrupted by novel therapeutic agents. Nonspecific local adjuvant therapies such as phenol or liquid nitrogen have been used in the treatment of giant cell tumor, but specific adjuvant therapies have not been described. The bisphosphonates pamidronate and Zoledronate can induce apoptosis in giant cell tumor culture in a dose-dependent manner. We established giant cell tumor cultures from patients with extensive destruction of bone. One of the four cultures formed osteoclastlike giant cells in vitro after more than six passages without exogenous receptor activator of NF-kappaB ligand or macrophage colony stimulating factor. Annexin V staining, presence of active cleaved form of caspase-3, and disappearance of poly (ADP-ribose) polymerase on Western blotting indicated activation of apoptosis by bisphosphonates in giant cell tumor. These results indicate that topical or systemic use of pamidronate or zoledronate can be a novel adjuvant therapy for giant cell tumor by targeting osteoclastlike giant cells, mononuclear giant cell precursor cells, and the autocrine loop of tumor osteoclastogenesis.
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PMID:Bisphosphonates may reduce recurrence in giant cell tumor by inducing apoptosis. 1534 59


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