The tandem array multiple shRNAs expression vector contained four shRNA expression cassettes targeting two genes. In HCT116 cells, the

multiple shRNAs expression constructs could efficiently and simultaneously induce inhibition of RhoA and RhoC genes and markedly inhibit the invasion and migration potentials Paclitaxel order of cancer cells. The inhibitory effects of multiple shRNAs expression vectors were more effective than single shRNA expression vector (data not shown). Further research work is being done to evaluate the inhibition effects of multiple shRNAs expression vectors on nude mice. To our knowledge, this is the first study that 4-tandem shRNA construct targeting RhoA and RhoC genes was proved to be a successful approach in reducing the malignance of colorectal tumor cells. Recent accumulating evidences have shown that

co-expression PLX4032 manufacturer of multiple shRNAs can simultaneously inhibit multiple genes or target multiple sites on a single gene, which demonstrated that multiple shRNAs expression system could inhibit all six genes and was much more efficient in inducing apoptosis in PC3 cells [28]. Moreover, a tandem Ku-shRNA-encoding plasmid expression system can knock-down Ku70 and Ku80 at the same time [29]. Furthermore, the vector that expresses five shRNAs targeting on rat ventricular myocyte Kir2.1 gene in tandem is able to suppress the expression of Kir2.1 in rat ventricular myocytes [30]. All these results including ours implicate that such shRNA-induced in tandem RNA interference may be used for dissecting complex signaling pathways and even be applied to targeting multiple

Idoxuridine genes in cancer therapy. Acknowledgements This work was supported by grants from the Natural Scientific Foundation of Shandong Province (Grant code: 2006ZRB14274) and the Research Program of Qingdao South District Municipal Science and Technology Commission. References 1. Schoenwaelder SM, Burridge K: Bidirectional signalling between the cytoskeleton and integrins. Curr Opin Cell Biol 1999, 11: 274–286.PubMedCrossRef 2. Bar-Sagi D, Hall A: Ras and Rho GTPases: a family reunion. Cell 2000, 103: 227–238.PubMedCrossRef 3. Sahai E, Marshall CJ: RHO-GTPases and cancer. Nat Rev Cancer 2002, 2: 133–142.PubMedCrossRef 4. Takai Y, Sasaki T, Matozaki T: Small GTP-binding proteins. Physiol Rev 2001, 81: 153–208.PubMed 5. Horiuchi A, Imai T, Wang C, Ohira S, Feng Y, Nikaido T, Konishi I: Up-regulation of small GTPases, RhoA and RhoC, is associated with tumour progression in ovarian carcinoma. Lab Invest 2003, 83: 861–870.PubMed 6. Kamai T, Tsujii T, Arai K, Takagi K, Asami H, Ito Y, Oshima H: Significant association of Rho/ROCK pathway with invasion and metastasis of bladder cancer. Clin Cancer Res 2003, 9: 2632–2641.PubMed 7. Sun HW, Tong SL, He J, Wang Q, Zou L, Ma SJ, Tan HY, Luo JF, Wu HX: RhoA and RhoC-siRNA inhibit the proliferation and invasiveness activity of human gastric carcinoma by Rho/PI3K/Akt pathway. World J Gastroenterol 2007, 13: 3517–3522.PubMed 8.