Non-receptor Src tyrosine kinases (nrTKs) are overexpressed in a variety of human tumors, including cancer of the colon, breast, and pancreas, and their inhibitors are under intensive investigations as novel anti-tumor agents. However, these studies are not clear in the case of cervical cancer. Therefore, we studied the role of nrTKs and their inhibitors in the cervical cancer. The expression level of phospho-Src(Y416) (pSrc(Y416)) in several cervical cancer cell lines, normal cervical tissues, and cervical cancer tissues have been examined, and it has also been done whether PP2, an inhibitor of Src kinase, can inhibit the growth of cervical cells in vitro and in vivo. Immunohistochemical and confocal microscope studies suggested that pSrc(Y416) is overexpressed in HeLa and SiHa cells, as well as in the clinical cervical cancer tissues, compared to the normal cervical tissues. Down-regulation of pSrc(Y416) inhibited the cell proliferation by increasing the HeLa or SiHa cell population in the G0-G1 phase or S phase, respectively. Down-regulation of pSrc(Y416) led to up-regulation of p21(Cip1) and p27(Kip1) in both HeLa and SiHa cells and decreased the expression of cyclin A1, cyclin E, and cyclin-dependent kinase-2,-6 (CDK-2,-6) in HeLa cells and of cyclin B and CDK-2 in SiHa cells. Nude mice xenograft data showed that PP2 inhibited subcutaneous tumor growth significantly (P < 0.05, compared with the control). Down-regulation of pSrc(Y416) contributes to cell growth inhibition in cervical cancer cells. nrTKs could therefore be a novel therapeutic targets for the treatment of cervical cancer.

PMID: 20532678 [PubMed - as supplied by publisher] Source: National Library of Medicine.