We hypothesize that early in prostate cancer progression, increased expression of YB-1 may increase P-gp activity which may in turn lower androgen levels in the prostate tumor cells.
Hypermethylation was more frequent in PCa than in BPH tissues (EDNRB, 100% versus 88%; TIG1, 96% versus 12%; RARbeta, 95% versus 35%; GSTP1, 93% versus 15%; APC, 80% versus 50%; MDR1, 80% versus 31%; PTGS2, 68% versus 15%; Reprimo, 59% versus 19%; and Annexin2, 4% versus 0%).
These data suggest that drug resistance in human prostate cancer may be multifactorial, with MRP and LRP frequently expressed in prostate cancer cells before antineoplastic drug treatment and P-gp expression occasionally acquired after drug exposure.
These results provide the first mechanistic link between expression of MRP1 and mutation of p53 in human prostate cancer and support recent clinical associations.
Previously, we described that MDR phenotype in PCa could be related with high basal and drug-induced expression of MDR proteins P-Glycoprotein (P-Gp), MRP1, and LRP.
In addition, we found deregulation of ABCB1, ABCB6, ABCC3, and ABCC10 in recurrent PCa samples and validated differential expression of ABCB6, ABCC3, and ABCC10 in recurrent PCa compared to non-recurrent PCa.
Since ABCC10 gene transcription in human prostate cancer CWR22Rv1 cells was found dependent on E2F binding sequence motif, ABCC10 expression in G<sub>1</sub> and S phases of the cell cycle of CWR22Rv1 cells, was analyzed.
QRT-PCR results demonstrated the elevated expression of ABCA5, ABCB1, ABCB6, ABCC1, and ABCC2 as well as reduced expression of ABCC3 in PCa samples compared to normal prostate tissues.
QRT-PCR results demonstrated the elevated expression of ABCA5, ABCB1, ABCB6, ABCC1, and ABCC2 as well as reduced expression of ABCC3 in PCa samples compared to normal prostate tissues.
Expression of eight ABC transporter genes (ABCA8, ABCB1, ABCC6, ABCC9, ABCC10, ABCD2, ABCG2, and ABCG4) was significantly down-regulated in PCa as compared to NPT, and only two genes (ABCC4 and ABCG1) were up-regulated.
Our results showed that modulation of MRP4 could be a mediator of ZEB1-related resistance to docetaxel in prostate cancer, making it a possible marker for chemotherapy response in patients who do not express MDR1.
Taken together, our results indicated that loss of miR-516a-3p expression and thus uncontrolled ABCC5 upregulation might drive PCa progression and influence chemosensitivity.
The identification of factors or peptides that can interrupt androgen-mediated AR-ARA interactions may be useful in the development of better antiandrogens for treating androgen-related diseases, such as prostate cancer.