Expression of protein kinase Cα and the MZF-1 and elk-1 transcription factors in human bladder transitional cell carcinoma cells.

In a recent study on hepatocellular carcinoma (HCC), we have shown that the transcription factors Myeloid Zinc Finger-1 (MZF-1) and Ets-like-protein 1 (Elk-1) are significantly related to protein kinase C alpha (PKCα) expression. The purpose of this study was to determine the correlation of the expression of PKCα with the expression of Elk-1 and MZF-1 in various differentiated urinary bladder transitional cell carcinoma (TCC) cell lines: 5637, BFTC905, TSGH8301, HT1376 and HT1197 cells. The malignant potential in the five TCC cell lines was examined by using cell proliferation/migration/invasion assay and the protein and mRNA levels of PKCα, ElK-1 and MZF-1 were examined by Western blot and RT-PCR analysis. The results showed that the rate of cell proliferation in the TSGH8301 cell line was higher than that in other cell lines, while there were obvious signs of cell migration and invasion in 5637, BFTC905 and HT1376 cells, and no sign in TSGH8301 and HT1197 cells. The resulting expression levels of Elk-1 and PKCα were the highest in 5637 cells, but the MZF-1 expression observed in all five cell lines showed no significant difference. To determine whether a correlation exists between PKCα and Elk-1, a shRNA knockout assay was performed and the results showed that the reduction of Elk-1 expression in 5637 cells did not result in the decreased PKCα expression. Therefore, although the findings showed elevated expression of Elk-1 and PKCα in 5637 cells, the regulator of PKCα in bladder cancer cells is yet to be determined.