Antitumor effect of dsRNA-induced p21WAF1/CIP1 gene activation in human bladder cancer cells

Abstract

We recently reported that synthetic dsRNAs targeting promoter regions can induce gene expression in a phenomenon referred to as dsRNA-induced gene activation/RNA activation (RNAa) [Li et al. Proc Natl Acad Sci U S A 2006;103:17337 -42]. The present study investigates the in vitro antitumor activity RNAa can elicit through triggering the expression of cell cycle repressor protein p21 WAF1/CIP1 (p21) in human bladder cancer cells. Transfection of a 21-nucleotide dsRNA targeting the p21 promoter (dsP21) was used to induce p21 expression in T24 and J82 bladder cancer cell lines. Reverse transcription-PCR and Western blot analysis accessed the increase p21 mRNA and protein levels, respectively, in transfected cells. In association to p21 induction, dsP21 transfection significantly inhibited bladder cancer cell proliferation and clonogenicity. Further analysis of cell viability and cell cycle distribution revealed that dsP21 transfection also enhanced apoptotic cell death and caused an accumulation in the G 1 phase in both cell lines. In conclusion, p21 activation by RNAa has antitumor activity in vitro in bladder cancer cells. These results suggest that RNAa could be used for cancer treatment by targeted activation of tumor suppressor genes. [Mol Cancer Ther 2008;7(3):698 -703]

Intravesical Delivery of Small Activating RNA Formulated into Lipid Nanoparticles Inhibits Orthotopic Bladder Tumor Growth

“…We previously showed that dsP21-322 possesses in vitro antigrowth activity in T24 and J82 bladder cancer cell lines (27). In the present study, we implement a chemically-modified variant of dsP21-322 (dsP21-322-2 0 F) with improved nuclease resistance and reduced immunostimulatory activity to improve its pharmaceutical properties for in vivo application (22).…”

“…Earlier in vitro studies have showed that dsP21-322 also possesses growth inhibitory function in T24 and J82 bladder cancer cell lines (27). To further evaluate dsP21-322 activity in bladder cancer, we transfected KU-7 and T24-P cells with dsP21-322 for 72 hours.…”

“…Overexpression of p21 has been reported to have proapoptotic function in several cancer cell types contributing to its tumor suppressor activity (12,27,30). To quantify the apoptotic cell fraction following duplex treatments, KU-7 cells were analyzed by flow cytometry following staining with 7-AAD and Annexin V-PE.…”

Suppressing tumourigenicity of prostate cancer cells by inhibiting osteopontin expression

“…Although RNAi is a technique widely used to suppress the expression of specific genes in a variety of studies (40)(41)(42) on different fields of molecular biology, the exact mechanisms on many aspects are not fully understood. Controversial results were reported by several laboratories (43)(44)(45). It was reported that several dsRNAs induce gene transcription in a sequence-specific manner by targeting the promoter region of various genes (44).…”

Double Stranded-Rna-Mediated Activation of P21 Gene Induced Apoptosis and Cell Cycle Arrest in Renal Cell Carcinoma

“…12 Although, recent reports have confirmed the potential tumor suppressor effect of dsRNA mediated p21 gene activation in different cancer cell lines, 3,7,13,14 none of these reports have investigated the action of dsRNA gene activation in renal cell carcinoma. Furthermore, while two of these studies have shown an increase in both early and late apoptotic cells following dsP21 transfection, 7, 15 the mechanism by which p21 leads to apoptosis is not well defined.…”