Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent clinical studies suggest that progesterone may be involved in the regulation of bone turnover and could promote bone formation. This study was undertaken to evaluate whether progesterone and promegestone (a 19 nor-PG derivative) may have a direct effect on human bone cells and, if so, whether growth factor production could be involved in promoting this effect. The osteosarcoma cell line TE85 and untransformed normal human osteoblastic cells derived from iliac crest were used as in vitro model systems. Progesterone and promegestone were found to significantly increase [3H]thymidine incorporation in TE85 cells in a dose-dependent manner at concentrations ranging from 10(-12) to 10(-8) mol/l after four days of cultivation (p less than 0.01, ANOVA). Consistent with this response in the TE85 cells, progesterone and promegestone increased cell number in human osteoblastic cells after six days of treatment (p less than 0.05, ANOVA). To determine whether this effect on cell proliferation was mediated by the insulin-like growth factor (IGF) regulatory system, the levels of IGF-1, IGF-2 and IGF binding protein (IGFBP) were measured in the conditioned media of both TE85 and human osteoblast cells. While no significant changes in IGF-1 levels were found in the conditioned media of progesterone and promegestone treated cultures, progesterone and promegestone at the concentration of 5 nmol/l significantly increased IGF-2 levels 2.4 and 1.5-fold respectively, at 48 h in the conditioned medium of TE85 cells as compared to control. Similarly, a 4.1 and 1.9-fold increase in IGF-2 levels was found upon treatment with progesterone and promegestone in human osteoblastic cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Progesterone and promegestone stimulate human bone cell proliferation and insulin-like growth factor-2 production. 137

1,25(OH)2D3 was found to regulate its own receptor levels via an increase in corresponding mRNA levels in human osteoblast-like osteosarcoma cells (MG-63). In addition, exposure of the cells for 24h to dexamethasone, estradiol, retinoic acid, or triiodothyronine resulted in a dose-dependent accumulation of hVDR mRNA. Combination of 1,25(OH)2D3 with any other hormone used in this study did not result in an additive increase in hVDR mRNA levels. Progesterone or dihydrotestosterone did not influence hVDR mRNA levels. Of the studied hormones, only 1,25(OH)2D3 was alone able to stimulate the synthesis and secretion of osteocalcin. Compared with 1,25(OH)2D3, the combination of 1,25(OH)2D3 and retinoic acid resulted an increased synthesis of osteocalcin. In contrast, the combination of 1,25(OH)2D3 with dexamethasone, estradiol, or triiodothyronine diminished the stimulatory effect of 1,25(OH)2D3. A complex interaction of several different hormone receptors seems to occur within the regulatory regions of hVDR and osteocalcin genes, or at the level of translation, resulting, in each case, a finely adjusted vitamin D receptor and osteocalcin expression.
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PMID:Hormonal regulation of vitamin D receptor levels and osteocalcin synthesis in human osteosarcoma cells. 165 30

Insulin-like growth factor-binding protein-5 (IGFBP-5) is produced by osteoblasts and potentiates insulin-like growth factor mitogenic stimulation in osteoblast cell cultures. Progesterone (PG) increased IGFBP-5 expression in normal human osteoblasts and increased IGFBP-5 transcription in U2 human osteosarcoma cells. We developed a chloramphenicol acetyltransferase reporter construct containing the human IGFBP-5 proximal promoter sequence, which includes TATA and CAAT boxes, and five putative PG response element half-sites. 10(-8) M PG increased promoter activity of this construct in U2 cells co-transfected with a PG receptor isoform A (PR(A)) expression vector. Analysis of 5' deletion constructs indicates that PG transactivation of IGFBP-5 promoter activity does not require the PG response element half-sites but does require the region -162 to -124 containing two tandem CACCC box sequences. Mutation of the proximal CACCC box at -139 eliminated PG transactivation. Gel shift assays using a -162 to -124 DNA fragment, U2 cell nuclear extracts, and purified PR(A) protein indicate that nuclear factors bind to a CACCC sequence at -139 and that PR(A) alters the pattern of transcription factor interaction with the CACCC sequence. Using a luciferase reporter construct containing base pairs -252 to +24 of the IGFBP-5 promoter, we found that both PR(A) and PR(B) isoforms mediated PG stimulation of promoter activity. These results suggest that PG may stimulate IGFBP-5 gene transcription via a novel mechanism involving PR and CACCC-binding factors.
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PMID:Progesterone stimulation of human insulin-like growth factor-binding protein-5 gene transcription in human osteoblasts is mediated by a CACCC sequence in the proximal promoter. 1047 2

In a series of experimental studies, it was shown that repetitive mild heat stress has antiaging hormetic effects on growth and various other cellular and biochemical characteristics of human skin fibroblasts undergoing aging in vitro. We have reported the hormetic effects of repeated challenge at the levels of maintenance of stress protein profile; reduction in the accumulation of oxidatively and glycoxidatively damaged proteins; stimulation of the proteasomal activities for the degradation of abnormal proteins; improved cellular resistance to ethanol, hydrogen peroxide, and ultraviolet-B rays; and enhanced levels of various antioxidant enzymes. Detailed analysis of the signal transduction pathways to determine alterations in the phosphorylation and dephosphorylation states of ERK, JNK, and p38 MAP kinases as a measure of cellular responsiveness to mild and severe heat stress is in progress. Furthermore, comparative studies using nonaging immortal cell lines, such as SV40-transformed human fibroblasts, spontaneous osteosarcoma cells, and telomerase-immortalized human bone marrow cells are also in progress for establishing differences in normal and cancerous cells for their responsiveness to mild and severe stresses.
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PMID:Mechanisms of hormesis through mild heat stress on human cells. 1524 85

Recent reports on the role of the membrane-cytoskeleton linker protein ezrin in sarcomas showed an effect on the formation of metastases, dependent on the level of ezrin expression. In this study, we explore the role of ezrin in Ewing's sarcoma, a frequently fatal mesenchymal neoplasm of children and young adults. Through both immunohistochemistry and Western immunoblot studies we find ubiquitous, high-level expression of ezrin in Ewing's sarcoma. In contrast to the observations in osteosarcoma and rhabdomyosarcoma, we demonstrate that inhibition of ezrin-mediated signal transduction, through the expression of a non-phosphorylatable T567A mutant, slows primary growth of Ewing's sarcoma cells in vitro. This reduction in growth is a result of increased apoptosis in the mutant expressing cells. We further show that expression of this mutant reduces the ability of Ewing's sarcoma cells to form experimental metastases in vivo. Molecular examination reveals that the action of ezrin in Ewing's sarcoma is dependent on the AKT/mTOR signal transduction cascade, but not MAP Kinase. These results, therefore, demonstrate that, in Ewing's sarcoma, the biology of ezrin is distinct from that described in other sarcomas. This study further validates ezrin as a potential therapeutic target.
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PMID:Ezrin mediates growth and survival in Ewing's sarcoma through the AKT/mTOR, but not the MAPK, signaling pathway. 1702 19

In a series of experimental studies we have shown that repetitive mild heat stress has anti-aging hormetic effects on growth and various other cellular and biochemical characteristics of human skin fibroblasts undergoing aging in vitro. We have reported the hormetic effects of repeated challenge at the levels of maintenance of stress protein profile; reduction in the accumulation of oxidatively and glycoxidatively damaged proteins; stimulation of the proteasomal activities for the degradation of abnormal proteins; improved cellular resistance to ethanol, hydrogenperoxide, and ultraviolet-B rays; and enhanced levels of various antioxidant enzymes. We are now undertaking a detailed analysis of the signal transduction pathways to determine alterations in the phosphorylation and dephosphorylation states of extracellular signal-related kinase, c-Jun terminal kinase and p38 MAP-kinases as a measure of cellular responsiveness to mild and severe heat stress. Furthermore, we are also undertaking comparative studies using non-aging immortal cell lines, such as SV40-transformed human fibroblasts, spontaneous osteosarcoma cells, and telomerase-immortalized human bone marrow cells for establishing differences in normal and cancerous cells with respect to their responsiveness to mild and severe stresses.
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PMID:Molecular mechanisms of anti-aging hormetic effects of mild heat stress on human cells. 1933 Jan 26

The introduction of multi-agent chemotherapy dramatically improved the outcome for patients with osteosarcoma. However, we appear to have reached a plateau in outcome with a long-term event-free survival of 60-70%. Therefore, detection of further improvements will likely require larger numbers of patients. This goal is best achieved via randomized clinical trials (RCTs) requiring large-scale cooperation and collaboration. With this background, four multinational groups agreed on the merits of collaboration: Children's Oncology Group (COG), Cooperative Osteosarcoma Study Group (COSS), European Osteosarcoma Intergroup (EOI) and Scandinavian Sarcoma Group (SSG); they designed a study to determine whether altering postoperative therapy based on histological response improved the outcome. The study design includes a backbone of 10 weeks of preoperative therapy using MAP (methotrexate, Adriamycin and cisplatin). Following surgery, patients are stratified according to histological response. Patients classified as "good responders" (>or=90% necrosis) are randomized to continue MAP or to receive MAP followed by maintenance pegylated interferon, while "poor responders" (<90% necrosis) are randomized to either continue MAP or to receive MAPIE (MAP+ifosfamide, etoposide). The design includes the registration of 1,400 patients over 4 years as well as the evaluation of quality of life using two different instruments. The group has established an efficient infrastructure to ensure successful implementation of the trial. This has included the EURAMOS Intergroup Safety Desk, which has established an international system for SAE, SAR and SUSAR reporting to the relevant competent authorities and ethics committees for each participating country. The group has also developed trial site monitoring and data center audits with funding from the European Science Foundation (ESF). The ESF has also funded three training courses to familiarize institutional staff with the requirements of multinational GCP trials. We have established a successful collaboration, and as of February 2008, 901 patients have been enrolled (COG 448; COSS 226; EOI 181; SSG 46) from 249 institutions in 16 different countries. As expected, 80% of the patients are <18 years of age, and accrual into the Quality of Life sub-study is proceeding as planned with 90% of the subjects agreeing to participate. International awareness is increasing and procedures for applicant countries wishing to join the collaboration have been implemented. Details about EURAMOS can be found at www.euramos.org. International trials in rare diseases are practicable with appropriate funding, planning and support. Although the implementation of such trials is difficult and time consuming, it is a worthwhile effort to rapidly complete RCTs and identify interventions that will improve the outcome of all osteosarcoma patients.EURAMOS-1 is the fastest accruing osteosarcoma trial and is already the largest osteosarcoma study conducted.
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PMID:International collaboration is feasible in trials for rare conditions: the EURAMOS experience. 2021

Friedreich ataxia is an autosomal recessive neurodegenerative disorder caused by mutations in the FXN gene that result in abnormally low levels of the mitochondrial protein frataxin. The authors recently used a lateral flow immunoassay to measure frataxin levels in a large cohort of controls, carriers, and patients with the condition. The findings show that frataxin levels do not appreciably change over time and correlate well with GAA(1) repeat length and age of onset; thus, frataxin is a reliable and stable marker for severity of disease. In this article, the authors present a patient diagnosed as having Friedreich ataxia and osteosarcoma who received combined methotrexate, doxorubicin (Adriamycin), and cisplatin (MAP) chemotherapy over 8 months. The authors assessed the effect of treatment on frataxin levels, blood cell counts, and clinical markers of cardiomyopathy. Results of the regimen and the use of MAP chemotherapy for treatment of neoplasms in individuals with Friedreich ataxia are discussed.
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PMID:Clinical monitoring in a patient with Friedreich ataxia and osteogenic sarcoma. 2275 83

It is widely accepted that canonical Wnt (cWnt) signaling is required for the differentiation of osteoprogenitors into osteoblasts. Furthermore, tumor-derived secretion of the cWnt-antagonist Dickkopf-1 (Dkk-1) is known to cause bone destruction, inhibition of repair and metastasis in many bone malignancies, but its role in osteosarcoma (OS) is still under debate. In this study, we examined the role of Dkk-1in OS by engineering its overexpression in the osteochondral sarcoma line MOS-J. Consistent with the known role of Dkk-1 in osteoblast differentiation, Dkk-1 inhibited osteogenesis by the MOSJ cells themselves and also in surrounding tissue when implanted in vivo. Surprisingly, Dkk-1 also had unexpected effects on MOSJ cells in that it increased proliferation and resistance to metabolic stress in vitro and caused the formation of larger and more destructive tumors than controls upon orthotopic implantation. These effects were attributed in part to upregulation of the stress response enzyme and cancer stem cell marker aldehyde-dehydrogenase-1 (ALDH1). Direct inhibition of ALDH1 reduced viability under stressful culture conditions, whereas pharmacological inhibition of cWnt or overexpression of ALDH1 had a protective effect. Furthermore, we observed that ALDH1 was transcriptionally activated in a c-Jun-dependent manner through a pathway consisting of RhoA, MAP-kinase-kinase-4 and Jun N-terminal Kinase (JNK), indicating that noncanonical planar cell polarity-like Wnt signaling was the mechanism responsible. Together, our results therefore demonstrate that Dkk-1 enhances resistance of OS cells to stress by tipping the balance of Wnt signaling in favor of the non-canonical Jun-mediated Wnt pathways. In turn, this results in transcriptional activation of ALDH1 through Jun-responsive promoter elements. This is the first report linking Dkk-1 to tumor stress resistance, further supporting the targeting of Dkk-1 not only to prevent and treat osteolytic bone lesions but also to reduce numbers of stress-resistant tumor cells.
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PMID:An unexpected role for a Wnt-inhibitor: Dickkopf-1 triggers a novel cancer survival mechanism through modulation of aldehyde-dehydrogenase-1 activity. 2457 91

Osteosarcoma (OS) is the most common primary aggressive and malignant bone tumor. Newly diagnostic OS patients benefit from the standard therapy including surgical resection plus radiotherapy and neoadjuvant chemotherapy (MAP chemotherapy: high-dose methotrexate, doxorubicin and cisplatin). However, tumor recurrence and metastasis give rise to a sharp decline of the 5-year overall survival rate in OS patients. Little improvement has been made for decades, urging the development of more effective therapeutic approaches. ErbB receptor family including EGFR, HER2, HER3 and HER4, being important to the activation of PI3K/Akt and MAPK signaling pathways, are potential targets for OS treatment. Genetic aberrations (amplification, overexpression, mutation and altered splicing) of ErbB are essential to the growth, apoptosis, motility and metastasis in a variety of cancers. Overexpression of ErbB family is associated with the poor prognosis of cancer patients. A number of monoclonal antibodies or inhibitors specific for ErbB family have entered clinical trials in a range of solid tumors including breast carcinoma, lung carcinoma and sarcoma. Here, we summarized the roles and expression of ErbB family in OS and the current development of ErbB-targeted therapeutic strategies including chemotherapies and immunotherapies for OS treatment.
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PMID:Advanced development of ErbB family-targeted therapies in osteosarcoma treatment. 3035 45


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