To further explore the relationship between miR-433 expression and p-Rb, we profiled native miR-433 expression by qRT-PCR in the parent A2780 cells and two other epithelial ovarian cancer (EOC) lines, PEO1 and PEO4.
Our study has made use of a panel of EOC lines with resistance to carboplatin, but we also used a cisplatin-resistant counterpart in parts of the study.
An initial microarray analysis of the human PEO1 human EOC line and novel drug resistant variants revealed low levels of the gene p57 Kip2 as a consequence of carboplatin resistance.
The human EOC cell lines SKOV3, SKOV3ip1, CAOV3, and Hey and the cisplatin-resistant EOC cell line A2780/CP were purchased from American Type Culture Collection (ATCC, Manassas, VA, USA).
Integrin clustering in the serous EOC cell lines OVCA 429 and OVCA 433 results in rapid loss of junctional E-cadherin, dissolution of adherens junctions and loss of surface-localized β-catenin [ 66]. β-Catenin is translocated to the nucleus wherein it activates transcription of Tcf/Lef target genes, including LRP6 and Wnt5a [ 66].
Based on our theory that cancer cells can be effected by DcR3 even when they do not over produce DcR3 we chronically cultured each of the 3 EOC cell lines in continuous DcR3 at 0.1 μg/ml for 12 weeks (approximately 20 passages) to determine if there were any effects on cell proliferation or response to platinum.
TOV21G was derived from a patient with a clear cell carcinoma, a disease which exhibits distinct clinical course that differs from HGSC, HGEC and undifferentiated adenocarcinomas, cancer types from which the other EOC cell lines were derived (see Table 1) [ 19].
Similarly, culturing the serous EOC cell line DOV13 in three-dimensional collagen gels leads to down-regulation of two secreted antagonists of Wnt signalling, CTGF (connective tissue growth factor) [ 139] and DKK1 [ 16].
In this study, we found an overexpression of uPA, CD44 and MDR1 and a colocalisation of uPA and CD44, uPA and MDR1, CD44 and MDR1 in cancer cells and stromal cells from most primary tumours and matched metastatic lesions, and further confirm the finding in EOC cell lines.
