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

The human topoisomerase I- and p53-binding protein topors contains a highly conserved, N-terminal C3HC4-type RING domain that is homologous to the RING domains of known E3 ubiquitin ligases. We demonstrate that topors functions in vitro as a RING-dependent E3 ubiquitin ligase with the E2 enzymes UbcH5a, UbcH5c, and UbcH6 but not with UbcH7, CDC34, or UbcH2b. Additional studies indicate that a conserved tryptophan within the topors RING domain is required for ubiquitination activity. Furthermore, both in vitro and cellular studies implicate p53 as a ubiquitination substrate for topors. Similar to MDM2, overexpression of topors results in a proteasome-dependent decrease in p53 protein expression in a human osteosarcoma cell line. These results are similar to the recent finding that a Drosophila topors orthologue ubiquitinates the Hairy transcriptional repressor and suggest that topors functions as a ubiquitin ligase for multiple transcription factors.
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PMID:Topors functions as an E3 ubiquitin ligase with specific E2 enzymes and ubiquitinates p53. 1524 80

Osteosarcoma (OS), a highly aggressive bone tumor, mainly occurs in young patients and always presents abnormalities in molecular biology, such as microRNAs (miRNAs). However, the characteristic and underlying mechanism of miR-671-5p in OS are still unclear. In this study, we certify that miR-671-5p is remarkably downregulated in OS tissues and cells. Overexpressed miR-671-5p can suppress OS cell proliferation in vivo and in vitro, by the way of arresting cell-cycle progression. The overexpression of cyclin D1 (CCND1) and CDC34 promotes cell proliferation and cell-cycle promotion, whose functions are contrary to miR-671-5p. miR-671-5p directly binds to CCND1 and CDC34, which are thought as the key factors in regulating cell cycle. Taken together, our results suggest that by targeting CCND1 and CDC34, miR-671-5p plays a tumor suppressor in OS to inhibit the development of OS, implicating it as a novel target for therapeutic intervention in OS.
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PMID:miR-671-5p Inhibits Tumor Proliferation by Blocking Cell Cycle in Osteosarcoma. 3139 66