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)

Polycomb (Pc) is involved in the stable and heritable repression of homeotic gene activity during Drosophila development. Here, we report the identification of a novel human Pc homolog, hPc2. This gene is more closely related to a Xenopus Pc homolog, XPc, than to a previously described human Pc homolog, CBX2 (hPc1). However, the hPc2 and CBX2/hPc1 proteins colocalize in interphase nuclei of human U-2 OS osteosarcoma cells, suggesting that the proteins are part of a common protein complex. To study the functions of the novel human Pc homolog, we generated a mutant protein, delta hPc2, which lacks an evolutionarily conserved C-terminal domain. This C-terminal domain is important for hPc2 function, since the delta hPc2 mutant protein which lacks the C-terminal domain is unable to repress gene activity. Expression of the delta hPc2 protein, but not of the wild-type hPc2 protein, results in cellular transformation of mammalian cell lines as judged by phenotypic changes, altered marker gene expression, and anchorage-independent growth. Specifically in delta hPc2-transformed cells, the expression of the c-myc proto-oncogene is strongly enhanced and serum deprivation results in apoptosis. In contrast, overexpression of the wild-type hPc2 protein results in decreased c-myc expression. Our data suggest that hPc2 is a repressor of proto-oncogene activity and that interference with hPc2 function can lead to derepression of proto-oncogene transcription and subsequently to cellular transformation.
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PMID:Interference with the expression of a novel human polycomb protein, hPc2, results in cellular transformation and apoptosis. 931 67

Osteosarcoma is the most common type of primary malignant tumor of skeletal with poor prognosis in children and adolescents. Accumulating evidence indicates that CBX2 is overexpressed in multiple human neoplasm and play a critical role in tumorigenesis and progression. However, its functional role and upstream regulation mechanism in osteosarcoma remain unknown. In the present study, tissue microarray (TMA) analysis was performed to determine the association between CBX2 expression and clinical prognosis of osteosarcoma patients by immunohistochemistry. We also investigated the functional role of CBX2 using small interfering RNA (siRNA) in vitro and in vivo. Additionally, we confirmed the direct binding between CBX2 and let-7a via qPCR, western blot and luciferase reporter assay. We found that CBX2 is dramatically upregulated in osteosarcoma tissues and high CBX2 expression was correlated with metastasis, recurrence, and chemotherapy response, as well as unfavorable prognosis in patients with osteosarcoma. Similar results were observed in a sarcoma cohort from The Cancer Genome Atlas (TCGA) dataset. Further experiments revealed that CBX2 knockdown significantly impeded osteosarcoma cell proliferation and invasion ability in vitro, and suppressed the tumor growth in tumor xenografts model. Mechanistically, we confirmed that CBX2 is a functional target of miRNA let-7a. Overexpression of let-7a inhibits osteosarcoma cell proliferation, which was reversed by CBX2 overexpression. Taken together, our study demonstrates that let-7a/CBX2 plays a crucial role in osteosarcoma progression. CBX2 could serve as a promising prognostic biomarker and potential therapeutic target for osteosarcoma patients.
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PMID:CBX2 is a functional target of miRNA let-7a and acts as a tumor promoter in osteosarcoma. 3115 Jan 56