Gemcitabine impacts differentially on bladder and kidney cancer cells: distinct modulations in the expression patterns of apoptosis-related microRNAs and BCL2 family genes

Bladder and renal cancer are two representative cases of tumors that respond differentially to gemcitabine. Previous studies have shown that gemcitabine can trigger apoptosis in various cancer cells. Herein, we sought to investigate the impact of gemcitabine on the expression levels of the BCL2 family members BCL2, BAX, and BCL2L12 and the apoptosis-related microRNAs miR-182, miR-96, miR-145, and miR-16 in the human bladder and kidney cancer cell lines T24 and Caki-1, respectively. Cancer cells' viability as well as the IC50 doses of gemcitabine were estimated by the MTT assay, while the detection of cleaved PARP via Western blotting was used as an indicator of apoptosis. Furthermore, T24 and Caki-1 cells' ability to recover from treatment was also monitored. Two different highly sensitive quantitative real-time RT-PCR methodologies were developed in order to assess the expression levels of BCL2 family genes and microRNAs. Exposure of cancer cells to gemcitabine produced the IC50 values of 30 and 3 nM for Caki-1 and T24 cells, correspondingly, while cleaved PARP was detected only in Caki-1 cells. T24 cells demonstrated the ability to recover from gemcitabine treatment, whereas Caki-1 cells' recovery capability was dependent on the initial time of exposure. BCL2 and BAX were significantly modulated in treated Caki-1 cells. Instead, T24 cells exhibited alterations only in the latter, as well as in all studied microRNAs. Therefore, according to our data, bladder and renal cancer cells' response to gemcitabine is accompanied by distinct alterations in the expression levels of their apoptosis-related genes and microRNAs.