Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The retinoblastoma (Rb) protein (pRb) has been studied in various crystalline NiS-transformed cell clones derived from the human osteoblast cell line, HOS TE-85. The parental HOS cells were not able to proliferate in soft agar medium, but they acquired this property following treatment with crystalline NiS. The pRb was found only in the hypophosphorylated form in 8 of 9 nickel-transformed clones examined, whereas in the parental cells the pRb appeared in both phosphorylated and unphosphorylated forms. Neither Rb gene expression nor its phosphorylation was affected by acute nickel treatments of HOS cells. The nickel-transformed HOS clones expressed the major regulators of Rb phosphorylation, cyclin E and cdk-2, at levels similar to those of the parental cells. In coimmunoprecipitation assays with cell lysates from the transformed clones that exhibited the hypophosphorylated form of pRb, the Rb protein failed to form a complex with simian virus 40 large T-antigen, indicating a lack of functional activity. When a plasmid containing the normal Rb gene was transfected into these nickel-transformed cells, it restored the Rb phosphorylation pattern observed in parental cells and the cells acquired a normal phenotype (i.e., they were no longer able to grow in soft agar). This suggested that a mutation was induced in nickel-transformed cells that affected the ability of the Rb protein to be phosphorylated and function normally, and this mutation allowed the human nickel-transformed cells to acquire anchorage-independent growth.
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PMID:Nickel-induced transformation of human cells causes loss of the phosphorylation of the retinoblastoma protein. 816 6

We examined the effects of inactivation of the RB gene on chemosensitivity of human osteosarcoma cell lines, using the MTT assay and calculating the inhibition index. Although the human osteosarcoma cell lines HOS and MG63 have a wild-type RB gene, SaOS-2 and OSrb (established from retinoblastoma patient) have no active RB gene. We used these 4 cell lines in growth inhibition assays for doxorubicin, cisplatin and methotrexate, and assessed the chemosensitivity. In the growth inhibition assay for methotrexate, cell lines lacking an active RB gene were more resistant than cell lines with an active RB gene.
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PMID:Effect of retinoblastoma tumor suppressor gene expression on chemosensitivity of human osteosarcoma cell lines. 1453 26