Abstract
BACKGROUND: Most human solid tumors are aneuploid; at the same time, polyploid cancer cells are found to be resistant to radiotherapy and chemotherapy and have a poor prognosis. The transforming growth factor beta induction (TGFBI) protein plays important roles in the development of tumors, depending on the cancer of origin. METHODS: In this study, we established polyploid clones of breast cancer treated with nocodazole. The drug sensitivity was measured by MTT assay. Western blot analysis was used to detect the expression of TGFBI protein in polyploid clones. The effects of paclitaxel on apoptosis, cell cycle and DNA ploidy were analyzed by flow cytometry. TGFBI protein expression was performed in samples from patients with epithelial ovarian tumors by immunohistochemical staining. RESULTS: We found that compared with the MDA-MB-231 cell line, the expression of TGFBI in the HGF1806 cell line was relatively higher. In addition, compared with its parental cells, TGFBI showed relatively low expression in the polyploid breast cancer cell line T-MDA-MB-231. Compared with the empty vector, under paclitaxel treatment, the over-expression of TGFBI in MDA-MB-231 and T-MDA-MB-231 both showed a higher growth inhibition rate. After nocodazole treatment, the over-expression of TGFBI in MDF-MB-231 cells proved that the expression of tetraploid cells was lower compared to the control. The positive rate of TGFBI expression in ovarian cancer specimens before chemotherapy was 33.3% (5/15), which was higher than the positive rate of TGFBI expression in ovarian cancer specimens matched with relapsed specimens after treatment (0%, 0/15). CONCLUSIONS: TGFBI can increase the sensitivity of paclitaxel in polyploid cancer cells and participate in the formation of polyploidy in MDA-MB-231 induced by nocodazole. This newly recognized role of TGFBI provides further insight into the pathogenesis of polyploid cancer and identifies potential new therapeutic targets.