Pyrrole-imidazole polyamide targeted to break fusion sites in TMPRSS2 and ERG gene fusion represses prostate tumor growth.
Bottom Line: Synthetic pyrrole-imidazole (PI) polyamides recognize and attach to the minor groove of DNA with high affinity and specificity.Our study identified that this PI polyamide repressed the cell and tumor growth of androgen-sensitive LNCaP prostate cancer cells.Targeting of these breakpoint sequences by PI polyamides could be a novel approach for the treatment of prostate cancer.
Affiliation: Department of Urology, Nihon University School of Medicine, Tokyo, Japan; Department of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.Show MeSH
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Mentions: Because previous reports show that TMPRSS2-ERG transcripts are induced in LNCaP cells by stimulation of DHT (100 nM) for 24 h,11–14 we analyzed LNCaP cells treated with the same protocol. To determine whether the fusion polyamide affects DHT-dependent inter-chromosomal movement and TMPRSS2-ERG expression in LNCaP cells, we performed FISH analysis and measured TMPRSS2-ERG expression levels using qRT-PCR. After DHT treatment, the number of cells showing co-localization of TMPRSS2 and ERG was significantly increased in LNCaP cells cultured in the presence of 5 μM of negative control polyamide (Fig.2). This DHT-induced inter-chromosomal movement, however, was significantly decreased in cells cultured with 5 μM of fusion polyamide. Although the TMPRSS2-ERG transcript was significantly and constantly expressed in VCaP cells, which harbor this fusion gene, its expression was induced to a detectable level by the stimulation with DHT in LNCaP cells. The expression of the TMPRSS2-ERG transcript was significantly suppressed in the presence of 5 μM of the fusion polyamide compared with 5 μM of negative control polyamide in LNCaP cells. In contrast, the fusion polyamide did not affect its expression in VCaP cells (Fig.3a). Moreover, we tested whether the fusion polyamide could downregulate endogenous ERG gene expression. Both 1 and 5 μM of fusion polyamide substantially reduced mRNA expression levels of ERG in LNCaP cells (Fig.3b).
Affiliation: Department of Urology, Nihon University School of Medicine, Tokyo, Japan; Department of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.