Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin D and its metabolites are best known for their actions in calcium and bone metabolism. However, epidemiological studies have suggested that an increased prostate cancer risk is associated with decreased production of vitamin D. In vitro and in vivo studies have shown that the biologically active form of vitamin D, 1alpha,25-dihydroxyvitamin D3 (1,25D), inhibits proliferation of cancer cells derived from multiple tissues, including the prostate. Although the mechanisms underlying the growth inhibitory effects of 1,25D have not been fully elucidated, in prostate cancer cells 1,25D reduces cell growth via a number of cellular pathways, including cell cycle arrest, induction of apoptosis, and altered activation of growth factor signaling. The hypercalcemia induced by 1,25D in vivo limits its use clinically as a therapeutic agent. However, several 1,25D analogs have been developed that reduce prostate tumor growth in rodent xenograft models without causing hypercalcemia. Additional studies are required in order to determine whether these 1,25D analogs will be useful therapeutic agents for the treatment of prostate cancer.
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PMID:Vitamin D and prostate cancer. 1504 10

Mice bearing LP07 lung adenocarcinoma show some characteristics that are similar to those present in patients with NSCLC. LP07 tumor-bearing mice develop the paraneoplastic syndromes of cachexia, leukocytosis and hypercalcemia. These symptoms may be partly due to a systemic inflammatory response. Our aim was to determine if treatment with NSAIDs would lower tumor and metastasis growth and their accompanying syndromes. The nonselective COX inhibitor indomethacin and the selective COX-2 inhibitor celecoxib reduced tumor growth and metastasis outcome in s.c. LP07 tumor-bearing mice. Both drugs also inhibited the development of leukocytosis and the weight loss associated with LP07 progression. Serum levels of the inflammatory cytokines IL-1beta and IL-6, mediators of cachexia, were modulated by NSAIDs. Inhibition of in vitro migration and invasion and reduction in angiogenesis were attained when cells were treated with either indomethacin or celecoxib. MMP-9 activity was also reduced in conditioned media from LP07 cells treated with celecoxib. These data suggest that several processes implicated in tumor progression can be modulated with NSAID treatment. Improvement in performance status through modulation of cachexia may offer a possibility for combining anti-inflammatory treatments with more aggressive therapies.
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PMID:Reduction of tumor progression and paraneoplastic syndrome development in murine lung adenocarcinoma by nonsteroidal antiinflammatory drugs. 1517 Jun 63

Bone metastasis are a frequent complication of cancer, occurring in up to 70% of patients with advanced breast or prostate cancer. The consequences of bone metastasis are often devastating. Osteolytic metastasis can cause different kinds of skeletal related events including severe pain, pathologic fractures, life-threatening hypercalcemia, spinal cord compression, and other nerve-compression syndromes. These skeletal-related events are the result of the resorption of mineralized bone by osteoclasts. Bisphosphonates are synthetic analogues of naturally occurring pyrophosphate compounds that inhibit bone resorption. Potent bisphosphonates, pamidronate and, more importantly zoledronic acid may cause hypocalcemia, but mostly asymptomatic, mild, transient in most cases. Sufficient calcium and vitamin D intake needs to be ensured in patients with malignancy who have borderline or low levels of calcium when commencing treatment with bisphosphonates. Vitamin D itself induce the formation of osteoclasts by increasing the expression of RANKL on marrow stromal cells. Local calcium also promotes tumor growth and the production of parathyroid hormone-related peptide which in turn stimulates bone resorption. Vitamin D and calcium supplementation during bisphosphonate administration for the purpose of elimination of the side effects related to hypocalcemia in patients with bone metastasis may increase the bone resorption and decrease the efficacy of bisphosphonates. Therefore, vitamin D and calcium supplementation must not be routinely recommended during bisphosphonate administration.
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PMID:Calcium and vitamin D supplementation during bisphosphonate administration may increase osteoclastic activity in patients with bone metastasis. 1569 11

Bone metastases commonly occur in the course of malignant tumor disease. For many years, attempts have been made to identify factors for the management of cancer-induced skeletal complications. Nowadays, synthetic antiresorptive agents are considered to be indispensable for the treatment of cancer-related skeletal events, such as bone metastasis. The most common of these drugs are the bisphosphonates, which represent one of the most significant advances over the last 10 years in the field of supportive care and cancer. They are used for the treatment of cancer-induced hypercalcemia, for the prevention and treatment of postmenopausal osteoporosis, for patients with bone metastases secondary to breast cancer and multiple myeloma. A third-generation bisphosphonate, zolendronate, has been shown to minimize the destructive consequences of bone metastases and to exert a profound effect on tumor-induced osteolysis and tumor growth in bone. Zoledronate is already used for the treatment of hypercalcemia of malignancy, multiple myeloma-related osteolytic events and for patients with documented bone metastases from solid tumors in conjunction with standard antineoplastic therapy. The structure-function activity of the three generations of bisphosphonates developed to date, the in vitro models used for studying their effects on osteoclasts and osteoblasts, as well as the results of clinical trials obtained by the third generation bisphosphonate, zoledronic acid, are presented.
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PMID:In vitro and in vivo antiresorptive effects of bisphosphonates in metastatic bone disease. 1579 91

Breast cancer metastasis to the bone occurs frequently, causing numerous complications including severe pain, fracture, hypercalcemia, and paralysis. Despite its prevalence and severity, few effective therapies exist. To address this, we examined whether the heat shock protein 90 (Hsp90) inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), would be efficacious in inhibiting breast cancer metastasis to bone. Utilizing the human breast cancer subline, MDA-MB-231SA, previously in vivo selected for its enhanced ability to generate osteolytic bone lesions, we determined that 17-AAG potently inhibited its in vitro proliferation and migration. Moreover, 17-AAG significantly reduced MDA-MB-231SA tumor growth in the mammary-fat pad of nude mice. Despite these findings, 17-AAG enhanced the incidence of bone metastasis and osteolytic lesions following intracardiac inoculation in the nude mouse. Consistent with these findings, 17-AAG enhanced osteoclast formation 2- to 4-fold in mouse bone marrow/osteoblast cocultures, receptor activator of nuclear factor kappaB ligand (RANKL)-stimulated bone marrow, and RAW264.7 cell models of in vitro osteoclastogenesis. Moreover, the drug enhanced osteoclastogenesis in human cord blood progenitor cells, demonstrating that its effects were not limited to mouse models. In addition to 17-AAG, other Hsp90 inhibitors, such as radicicol and herbimycin A, also enhanced osteoclastogenesis. A pro-osteolytic action of 17-AAG independent of tumor presence was also determined in vivo, in which 17-AAG-treated tumor-naive mice had reduced trabecular bone volume with an associated increase in osteoclast number. Thus, HSP90 inhibitors can stimulate osteoclast formation, which may underlie the increased incidence of osteolysis and skeletal tumor incidence caused by 17-AAG in vivo. These data suggest an important contraindication to the Hsp90 targeted cancer therapy currently undergoing clinical trial.
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PMID:The heat shock protein 90 inhibitor, 17-allylamino-17-demethoxygeldanamycin, enhances osteoclast formation and potentiates bone metastasis of a human breast cancer cell line. 1593 Mar 15

Multiple myeloma is the most common form of plasma cell dyscrasia and virtually all cases of myeloma exhibit osteolytic lesions, which result in bone pain, pathological fractures, spinal cord compression, and hypercalcaemia. Malignant plasma cells disrupt the delicate balance between bone formation and bone resorption, which ultimately leads to the debilitating osteolytic lesions. This review focuses principally on mechanisms of osteoblast inhibition by malignant plasma cells with emphasis placed on our experimental findings, which support a model for abnormal Wnt signaling in osteoblast suppression. We describe how excessive amounts of soluble Wnt inhibitors secreted by malignant plasma cells in multiple myeloma could promote osteolytic lesions, tumor growth, suppress hematopoiesis, prevent proper engraftment, and expansion of transplanted stem cells. Finally, we detail current therapies shown to disrupt the interaction between the myeloma cell and the microenvironment, leading to activation of osteoblasts.
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PMID:Role of osteoblast suppression in multiple myeloma. 1644 Mar 24

Mice bearing LP07 lung adenocarcinoma present some characteristics similar to those shown in patients with several malignant diseases. LP07 tumor bearers develop paraneoplastic syndromes such as cachexia, leukocytosis, and hypercalcemia, partly due to a systemic inflammatory response. We analyzed some of the mechanisms involved in the effectiveness of the association of the appetite-stimulant medroxiprogesterone acetate (MPA) and the nonselective cyclooxigenase (COX) inhibitor indomethacin (INDO) in LP07 tumor bearing mice. INDO and INDO plus MPA treatments significantly inhibited tumor growth, which was not inhibited by MPA. The number of lung metastatic nodules was decreased with all treatments, being most effective INDO alone and INDO plus MPA. A significant decrease of plasmatic levels of the matrix metalloproteinases MMP-9 and MMP-2 correlated with these results. Paraneoplastic syndromes, leukocytosis, and cachexia were abolished by all treatments. We determined effects of the treatments on circulating cytokines shown to regulate cachexia and inflammation. Both treatments alone, and INDO plus MPA, reduced circulating IL-6 throughout tumor evolution. A pronounced increase in serum IL-1ss levels was detected in untreated tumor bearers. These levels decreased and were closer to normal serum values when LP07 mice were treated with INDO plus MPA. The combination of a nonsteroidal antiinflammatory drug as INDO and MPA showed to be effective in inhibiting tumor and metastatic growth and diminishing paraneoplastic symptoms and SIR. A variety of specific molecules are implicated as playing a role in cancer-induced cachexia and hematological alterations.
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PMID:Inhibition of tumor progression and paraneoplastic syndrome development in a murine lung adenocarcinoma by medroxyprogesterone acetate and indomethacin. 1653 80

Osteoprotegerin (OPG) acts as a decoy receptor for receptor activator of NF-kappaB ligand (RANKL), which is a pivotal molecule required for osteoclast formation. In vitro OPG inhibits osteoclast formation and in vivo (administered as Fc-OPG) it reduces hypercalcemia and the establishment of osteolytic lesions in mouse models of tumor cell growth in bone. Osteolysis can be induced by parathyroid hormone-related protein (PTHrP) produced by breast cancer cells that results in an increased osteoblastic RANKL/OPG ratio. We examined the effect of local tumor production of OPG on the ability of breast cancer cells to establish and grow in bone and mammary fat pad. MCF-7 cells or MCF-7 cells overexpressing PTHrP were transfected with full-length OPG and inoculated into the proximal tibiae of athymic nude mice. Mice injected with cells overexpressing PTHrP and OPG showed enhanced tumor growth, increased osteolysis (2-fold compared with MCF-7 cells overexpressing PTHrP), and altered histology that was reflective of a less differentiated (more aggressive) phenotype compared with MCF-7 cells. In contrast, administration of recombinant Fc-OPG reduced tumor growth and limited osteolysis even in mice inoculated with OPG overexpressing cells. Similarly, OPG overexpression by breast cancer cells enhanced tumor growth following orthotopic inoculation. These results indicate that OPG overexpression by breast cancer cells increases tumor growth in vivo and that there are strikingly different responses between therapeutically administered Fc-OPG and full-length OPG produced by tumor cells.
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PMID:Osteoprotegerin overexpression by breast cancer cells enhances orthotopic and osseous tumor growth and contrasts with that delivered therapeutically. 1658 87

The extracellular calcium-sensing receptor (CaR) plays a key role in the defense against hypercalcemia by "sensing" extracellular calcium (Ca2+(o)) levels in the parathyroid and kidney, the key organs maintaining systemic calcium homeostasis. However, CaR function can be aberrant in certain pathophysiological states, e.g., in some types of cancers known to produce humoral hypercalcemia of malignancy (HHM) in humans and animal models in which high Ca2+(o), via the CaR, produces a homeostatically inappropriate stimulation of parathyroid hormone-related peptide (PTHrP) secretion from these tumors. Increased levels of PTHrP set a cycle in motion whereby elevated systemic levels of Ca2+(o) resulting from its increased bone-resorptive and positive renal calcium-reabsorbing effects give rise to hypercalcemia, which in turn begets worsening hypercalcemia by stimulating further release of PTHrP by the cancer cells. I review the relationship between CaR activation and PTHrP release in normal and tumor cells giving rise to HHM and/or malignant osteolysis and the actions of the receptor on key cellular events such as proliferation, angiogenesis, and apoptosis of cancer cells that will favor tumor growth and osseous metastasis. I also illustrate diverse signaling mechanisms underlying CaR-stimulated PTHrP secretion and other cellular events in tumor cells. Finally, I raise several necessary questions to demonstrate the roles of the receptor in promoting tumors and metastases that will enable consideration of the CaR as a potential antagonizing/neutralizing target for the treatment of HHM.
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PMID:Effects of calcium-sensing receptor on the secretion of parathyroid hormone-related peptide and its impact on humoral hypercalcemia of malignancy. 1660 23

Human parathyroid hormone-related protein (hPTHrP), identified in patients with paraneoplastic hypercalcemia and expressed by different cell types during development and adult life, plays important roles in many human neoplasms. Immunohistochemical and RT-PCR analyses of hPTHrP and human parathyroid hormone receptor type 1 (PTHR-1) in primary medulloblastoma confirmed their expression in both classic and desmoplastic variants at RNA and protein levels. To evaluate the functional role of hPTHrP, DAOY and D283 medulloblastoma and U87MG glioma cells, expressing high levels of hPTHrP and PTHR-1, were treated with anti-sense oligonucleotides for hPTHrP. Anti-sense treatment produced in all cell lines a decrease of cell proliferation and clonogenic activity and an increase of apoptosis, while addition of exogenous hPTHrP (1-37) prevented these effects. Anti-sense induced the increase of Caspase-3, Fas (CD95) mRNAs and Bax/Bcl-2 mRNA ratio after 12 h of cell treatment. Exogenous hPTHrP (1-37) increased intracellular Ca(2+) concentration in DAOY cells as revealed by FURA. Anti-sense treated cells showed a significant decrease of steady-state levels of intracellular Ca(2+), which was reverted by addition of exogenous hPTHrP (1-37). This study indicates that hPTHrP and PTHR-1 are expressed in medulloblastoma and could promote tumor growth, protecting cells from apoptosis.
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PMID:Human parathyroid hormone-related protein and human parathyroid hormone receptor type 1 are expressed in human medulloblastomas and regulate cell proliferation and apoptosis in medulloblastoma-derived cell lines. 1737 45


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