Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0153690 (bone metastases)
 6,382 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The current paradigm for drug discovery requires the identification of a target involved in the disease process (e.g. enzyme or receptor) and the development of an appropriate ligand (activator, inhibitor or selective modulator). Selection of ligands for clinical development is based on the therapeutic window between efficacy vs. safety and ADME (absorption, distribution, metabolism and elimination) considerations. For bisphosphonates (BPs) the process has not followed that paradigm. BPs have very low absorption and are retained in bone, their target tissue. A few have been used on a limited basis for over 20 years in diseases of rapid bone destruction (e.g. post-menopausal osteoporosis, Paget's disease, bone metastases, etc.), without understanding their molecular mechanism of action. The nitrogen-containing BPs (N-BPs) are the latest and most potent addition to this family of compounds and have the widest use. They have high potency, are specifically targeted to the osteoclast on bone and are used at very low doses (5-10 mg clinically). Over the last four years, there was significant progress in elucidating the mechanism of action of BPs, both lacking and containing nitrogen. This review will focus on the mechanism of action of the N-BPs, specifically alendronate (ALN) and risedronate (RIS), the two agents most widely used. For these and all other N-BPs, the molecular target is the isoprenoid biosynthetic enzyme, farnesyl diphosphate synthase, in the cholesterol biosynthesis pathway. Although inhibition of this enzyme by N-BPs results in the suppression of sterol biosynthesis, it is actually disruption of a branch pathway, isoprenylation, that is responsible for N-BP pharmacological activity. Isoprenylation involves covalent linkage of the 15 or 20 carbon isoprene moiety farnesyl diphosphate or geranylgeranyl diphosphate, respectively, to the carboxy-terminus of regulatory proteins, including the small GTPases Ras, Rac, Rho and Cdc42. The latter three, as well as numerous others, are geranylgeranylated and play a rate-limiting role in the activity of the bone-resorbing osteoclast. This targeted osteoclast inhibition accounts for the potency of the N-BPs and for their ability to elicit the desired therapeutic response of suppressing bone turnover. The occasional gastrointestinal irritation caused by N-BPs appears to be mechanism-based and is also briefly reviewed.
 ...
PMID:Nitrogen-containing bisphosphonate mechanism of action. 1537 39

Clodronate (clodronate disodium, Bonefos) is a non-nitrogen-containing bisphosphonate that inhibits osteoclast activity, and thereby inhibits bone resorption. Clodronate has been extensively used in patients with advanced breast cancer, and is generally well tolerated. In patients with primary breast cancer, clodronate is currently the only bisphosphonate shown to improve survival rates and to reduce the incidence of bone metastases in randomised controlled trials. Further trials in patients with early breast cancer are warranted to confirm results to date and to determine the optimal duration of treatment, as well as the efficacy of the drug compared with other bisphosphonates. In the meantime, clodronate is a well established bisphosphonate which has shown beneficial effects in the prevention of bone metastases and on survival in patients with primary breast cancer.
 ...
PMID:Clodronate : a review of its use in the prevention of bone metastases and the management of skeletal complications associated with bone metastases in patients with breast cancer. 1555 53

Osteocytes, the most abundant bone cell type with important roles in tissue maintenance and pathological aberrations such as observed in bone metastases, are enclosed within a highly compact, calcified extracellular matrix. This location complicates analysis in native bone, with the consequence that despite their importance their in vivo molecular physiology is only poorly understood. We have examined the possibility of isolating osteocyte RNA for transcript profiling from native, frozen bone instead of employing the formalin-fixed, paraffin-embedded, decalcified version routinely used in histology, providing chemically modified and highly disintegrated RNAs. Bone tissue was tape-assisted cryosectioned and fixed to glass slides by support of UV-flash-triggered adhesive polymerization followed by quick hematoxylin-eosin staining to generate a guidance image for microdissection. Using an UVa-nitrogen laser, matrix-enclosed osteocytes were either excised and catapulted into RNA preparation vials or freed of accompanying nonosteocyte cellular material. The influences of bone sectioning, staining, and osteocyte capturing procedures on the prepared osteocyte RNAs were analyzed and the method was optimized accordingly. The obtained osteocyte RNAs showed the expected expression pattern of marker genes (reverse transcriptase-polymerase chain reaction), and, following conversion into fluorescent-labeled cDNAs, led to transcript profiles (cDNAchips; 2600 genes) with scatter-graph geometries indicating suitability for high-confidence evaluation. With the approach described here we introduce a methodological way for the characterization of the in vivo molecular physiology of osteocytes by functional genomics.
 ...
PMID:High-quality RNA preparation for transcript profiling of osteocytes from native human bone microdissections. 1555 65

With recent advances in cancer management, patients with metastatic bone disease are likely to have a prolonged clinical course, with skeletal-related events such as pain, hypercalcemia, pathologic fractures, spinal cord and nerve compression. Bisphosphonate use has resulted in the reduction of skeletal-related complications for a number of tumors including breast, prostate and myeloma, and improvements in the quality of life for patients. There is now evidence that newer, highly potent, nitrogen-containing bisphosphonates reduce skeletal complications in patients with bone metastases from other solid tumors (including lung cancer). The early identification of patients at high risk for developing bone metastases may help curtail a complex and costly clinical problem--skeletal-related events. In this article, we review the different mechanisms of bisphosphonates and the potential role of newer-generation bisphosphonates, such as zoledronic acid, in the management of advanced, metastatic bone disease. We include a review of mechanistic studies and preclinical data. Additionally, the utility of evolving concepts such as bone markers and imaging of bone metastases are discussed.
 ...
PMID:The role of bisphosphonates in the management of advanced cancer with a focus on non-small-cell lung cancer. Part 1: Mechanisms of action, role of biomarkers and preclinical applications. 1577 88

Newer-generation intravenous bisphosphonates have resulted in the reduction of skeletal-related complications, i.e. skeletal-related events (SREs) such as pain, hypercalcemia, pathologic fractures and spinal cord and nerve compression, as well as improvements in the quality of life in patients with metastatic bone disease who are likely to have a prolonged clinical course. Highly potent, nitrogen-containing bisphosphonates such as zoledronic acid reduce SREs in patients with bone metastases from other solid tumors (including lung cancer). Part one of our review discussed the mechanisms of action by bisphosphonates as well as potential roles for bone markers and imaging in lung cancer. In this article, part two of our review, we examine the economic and clinical impact of bisphosphonates in lung cancer, with a focus on the potential role of newer-generation bisphosphonates in the management of advanced, metastatic bone disease of lung cancer.
 ...
PMID:The role of bisphosphonates in the management of advanced cancer with a focus on non-small-cell lung cancer. Part 2: Clinical studies and economic analyses. 1577 89

Bisphosphonates have demonstrated important clinical benefits for patients with malignant bone disease, metabolic bone diseases, such as Paget's disease, and postmenopausal osteoporosis. The introduction of nitrogen-containing bisphosphonates with high affinity for hydroxyapatite in bone represents an important advancement. These agents are now a standard of care for osteoporosis, Paget's disease, osteogenesis imperfecta, primary bone lesions from multiple myeloma and bone metastases from breast cancer. Moreover, the recent clinical development of zoledronic acid (4 mg by 15-minute intravenous infusion) has expanded the benefits of bisphosphonate therapy to patients with bone metastases from any solid tumour. Bisphosphonates are also being investigated at present for the prevention of bone loss resulting from cancer therapy. In addition, a variety of novel biologic agents, receptor activator of nuclear factor-kappaB (RANK) ligand antibodies, osteoprotegerin and cathepsin K inhibitors are being investigated at present for the treatment of malignant bone disease. The management of bone health is an important area of active research, and the armamentarium and role of bone-specific therapies continue to expand.
 ...
PMID:New therapeutic agents for the treatment of bone diseases. 1595 12

Olpadronate is a nitrogenated bisphosphonate. Although it shares the therapeutic and pharmacological properties of pamidronate and alendronate, it has a greater dosage amplitude, more predictable effects and a greater digestive tolerability than other bisphosphates. Therefore, it may be more appropriate in the treatment of medical osteopathies, by both oral and parenteral routes of administration. According to various experimental and human models, the pharmacological potency of olpadronate is 5- to 10-times higher than that of pamidronate and close to that of alendronate. The two methyl groups bound to the nitrogen atom give the compound a high water solubility, which is about 8-times higher than that of the two other bisphosphonates. The lack of a terminal amino group in the side-chain of the molecule and the absence of crystallised forms of the compound in the digestive tract (due to its high water solubility) may avoid the potential for inducing oesophageal and gastrointestinal side-effects. These features may explain the high tolerability reported after the administration of doses of olpadronate (by the oral route) up to 5- to 10-times higher than the maximum tolerated dose of alendronate in Paget's bone disease and bone metastases, thus widening the possibilities for its clinical usage. In addition, initial pharmacokinetic studies suggest that olpadronate's oral bioavailability would fit into a confidence range of 2-4%, which contrasts with the erratic absorption shown by other highly potent bisphosphonates. The clinical efficacy demonstrated in preliminary studies in Paget's bone disease (including ultra-short treatments), and also in single-dose iv. therapy of hypercalcaemia of malignancies, renders olpadronate among the most promising bisphosphonate compounds, with potential use in the treatment of a variety of bone-involving diseases, such as osteoporosis, malignancies and rheumatoid arthritis.
 ...
PMID:Olpadronate: a new amino-bisphosphonate for the treatment of medical osteopathies. 1599 50

Intravenous bisphosphonates are the preferred treatment to prevent skeletal complications for patients with breast cancer and bone metastases. Pamidronate, a single-nitrogen bisphosphonate, was the early standard of care for such patients based on 2 large, placebo-controlled trials involving 754 patients. Zoledronic acid, a new-generation bisphosphonate containing 2 nitrogens, was evaluated in 1130 patients with breast cancer in a large, randomized, comparative, phase III trial with pamidronate. At 25 months, zoledronic acid (4 mg) significantly reduced the overall risk of developing a skeletal-related event (SRE) by an additional 20% versus 90 mg pamidronate by multiple-event analysis. Furthermore, zoledronic acid was at least as effective as pamidronate in reducing the proportion of patients with > or = 1 SRE and in delaying the onset of SREs. Moreover, a retrospective subset analysis of 352 patients with > or = 1 osteolytic lesion proved zoledronic acid more effective than pamidronate in reducing the risk and delaying the onset of SREs. Intravenous ibandronate (6 mg via 1-2-hour infusion) was evaluated in a placebo-controlled, phase III trial of 466 patients and was significantly more effective than placebo in reducing the number of 12-week treatment periods in which an SRE occurred. The safety profiles among all intravenous bisphosphonates were similar; patients treated with intravenous bisphosphonates reported notably less bone pain but a higher incidence of mild to moderate transient infusion-related adverse events (eg, nausea, vomiting, myalgia, and anorexia) compared with placebo. In summary, intravenous bisphosphonates are effective for the treatment of bone metastases in patients with breast cancer and have similar safety profiles, but the shorter infusion time and greater efficacy of zoledronic acid in reducing overall skeletal morbidity provide advantages over other available agents.
 ...
PMID:Efficacy and safety of intravenous bisphosphonates for patients with breast cancer metastatic to bone: a review of randomized, double-blind, phase III trials. 1600 90

Bone metastases are a major cause of cancer morbidity. Bone metastases are associated with pain, fractures, spinal cord compression, ineffective haematopoiesis, and hypocalcaemia of malignancy. The goals of treatment for bone metastases are to prevent disease-related skeletal complications, palliate pain, and maintain quality of life. Bisphosphonates are a standard part of supportive care for patients with bone metastases. Zoledronic acid, a nitrogen containing third generation bisphosphonate, is the most active and is the most thoroughly investigated bisphosphonate for metastatic bone disease. The efficacy and safety of zoledronic acid has been established in three pivotal prospective, randomized controlled trials involving more than 3000 subjects. The evidence is reviewed here with a focus on clinical relevance. Across a broad array of tumour types, zoledronic acid (4 mg intravenously over 15 min every 3-4 weeks) decreased the frequency of skeletal-related events, delayed the time to a first skeletal-related event, and reduced pain. Zoledronic acid is more effective than pamidronate in breast cancer and the only bisphosphonate proven effective for metastatic prostate cancer, lung cancer, renal cell carcinoma and other solid tumours.
 ...
PMID:Zoledronic acid to prevent skeletal complications in cancer: corroborating the evidence. 1622 55

Ibandronic acid (Bondronat) is a potent, new-generation, nitrogen-containing bisphosphonate, available in both intravenous and oral formulations, which effectively inhibits osteoclast-mediated bone resorption. In clinical trials, the two formulations were equally effective in preventing skeletal-related events and improving quality of life in patients with bone metastases of breast cancer. Both intravenous and oral ibandronic acid reduced metastatic bone pain scores below baseline levels for up to 2 years. Oral ibandronic acid is administered as a single 50 mg tablet taken once daily. It suppressed bone resorption in breast cancer patients with bone metastases to an extent similar to that observed with intravenous zoledronic acid. Both intravenous and oral ibandronic acid were well tolerated with no evidence of renal toxicity. Ibandronic acid is therefore a valuable addition to the bisphosphonates used in the treatment of bone metastases of breast cancer, offering high potency and the convenience of oral administration, combined with the absence of renal toxicity.
 ...
PMID:Ibandronic acid: a review of its use in the treatment of bone metastases of breast cancer. 1662 Jan 48


<< Previous 1 2 3 4 5 6 7 8 Next >>