Stable suppression of tumorigenicity by virus-mediated RNA interference

Abstract

Most human tumors harbor multiple genetic alterations, including dominant mutant oncogenes. It is often not clear which of these oncogenes are continuously required and which, when inactivated, may inhibit tumorigenesis. Recently, we developed a vector that mediates suppression of gene expression through RNA interference. Here, we use a retroviral version of this vector to specifically and stably inhibit expression of only the oncogenic K-RAS(V12) allele in human tumor cells. Loss of expression of K-RAS(V12) leads to loss of anchorage-independent growth and tumorigenicity. These results indicate that viral delivery of small interfering RNAs can be used for tumor-specific gene therapy to reverse the oncogenic phenotype of cancer cells.

MicroRNAs targeting mutant K-ras by electrotransfer inhibit human colorectal adenocarcinoma cell growth in vitro and in vivo

“…Most studies dealing with K-ras silencing reported that siRNA or shRNA molecules could specifically inhibit mutant K-ras expression while leaving the WT K-ras unaffected although their sequences differed only in one nucleotide. [8][9][10][11]13 In our study, siRNA molecules that targeted K-ras mRNA outside the region with mutated codon reduced the levels of mRNA and protein of K-ras in both LoVo cells with mutated K-ras and in HT29 cells harboring WT K-ras. However, our results demonstrated that in HT29 cells, in which their oncogenic potential is due to other mutations, the effect of silencing K-ras did not reflect on cell survival.…”

“…The obtained results are consistent with the results from other in vitro studies performed mostly on pancreatic cell lines (Capan-1, Panc-1, MiaPaca-2 and PC-7), in which therapeutic potential of siRNA/ short hairpin RNA (shRNA) molecules directed against K-ras was also shown. [8][9][10][11][12][13] Furthermore, due to a relatively short half-life of synthetic siRNA molecules, 12,13,29,32 we constructed plasmid DNA that encoded a hairpin type of silencing molecules, that is, miRNA molecules with a sequence corresponding to the most efficient siRNA molecule (pmiRNA-K-ras). Most studies dealing with K-ras silencing reported that siRNA or shRNA molecules could specifically inhibit mutant K-ras expression while leaving the WT K-ras unaffected although their sequences differed only in one nucleotide.…”

“…It was shown that properly designed small interfering RNA (siRNA) sequences efficiently inhibited the expression of mutated K-ras, whereas expression of wild-type (WT) K-ras remained unaffected. [8][9][10][11][12] The inhibition of K-ras expression by RNAi was reflected in reduced K-ras mRNA and proteins level, reduced proliferation and migration of cells, increased apoptosis, reduced angiogenic potential and decreased production of vascular endothelial cells. In the experiments, in vivo, on pancreatic tumors, delay in tumor growth was observed.…”

Oncolytic adenovirus-mediated shRNA against Apollon inhibits tumor cell growth and enhances antitumor effect of 5-fluorouracil

“…To surmount these limitations, several groups have developed DNA-vector-mediated or virus-vectormediated mechanisms to express short hairpin RNAs (shRNAs) that can be converted into siRNAs in vivo. [20][21][22][23] Oncolytic adenoviral vector permits the efficient delivery and stable expression of shRNA constructs in a range of mammalian cells. Furthermore, oncolytic adenoviral vector has the distinct advantage of propagation in tumor cells, which can infect adjacent tumor cells and leave normal cells almost unaffected.…”

Calcium carbonate nanoparticle delivering vascular endothelial growth factor-C siRNA effectively inhibits lymphangiogenesis and growth of gastric cancer in vivo

“…10 Several reports have described a significant correlation between VEGF-C expression, tumor lymphangiogenesis and regional lymph-node metastasis in some tumors. [11][12][13][14][15][16][17][18] Therefore, inhibition of VEGF-C activity or disabling VEGF-C receptor function may be useful to inhibit tumor growth and metastasis.…”