Antitumor effect of dsRNA-induced p21(WAF1/CIP1) gene activation in human bladder cancer cells.
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.
Chen
Zhong
Z
Department of Urology, University of California San Francisco, San Francisco, CA 94143, USA.
Place
Robert F
RF
Jia
Zhe-Jun
ZJ
Pookot
Deepa
D
Dahiya
Rajvir
R
Li
Long-Cheng
LC
D015153:Blotting, Western; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D001749:Urinary Bladder Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000473:pathology
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D012330:RNA, Double-Stranded; D020928:Mitogen-Activated Protein Kinases