Androgen deprivation therapy regulation of β1C integrin expression in prostate cancer

The β1C integrin is an alternatively spliced variant of the β1 integrin subfamily that at variance with its wild-type counterpart, i.e., the β1A integrin, inhibits cell proliferation in prostate cancer cells. We have recently shown that transcriptional, translational and post-translational processes contribute to the selective loss of β1C integrin during prostate malignant transformation. Here, we investigated whether androgen deprivation therapy (ADT) may affect β1C mRNA expression in prostate cancer. Neoplastic prostates were obtained from patients undergoing radical prostatectomy who had received neoadjuvant ADT. The β1C mRNA level was measured by Northern hybridization experiments and compared to normal prostates obtained from patients who underwent radical cystoprostatectomy for bladder cancer. Furthermore, the β1C integrin gene transcriptional activity was measured by nuclear Run-on assays. We found an increase of β1C mRNA expression (208±11%; p<0.01) in patients who received ADT in comparison to those who did not. Furthermore, we demonstrated an increase of gene transcriptional activity (360±10%; p<0.01) possibly partially or completely responsible for the regulation of the β1C integrin mRNA levels. Short-term administration of ADT seems to interfere with β1C integrin expression, suggesting the existence of androgen-mediated pathways involving β1C. Precise characterization of the mechanisms that regulate the expression of this factor in cancer cells will provide further insight into the molecular mechanisms involved in tumor progression and possibly contribute to the identification of molecular targets for the development of new therapeutic strategies.