[Construction and identification of CerbB-2 siRNA expression plasmid and its transfer into human colon cancer cell lines HT-29].

To construct a plasmid carrying small interfering RNA (siRNA) targeting human C-erbB2 gene (pGenesil- erbB2) and test its effect on Her-2 expression at the post-transcriptional level in human colon cancer cell lines HT-29 cells that highly express erbB2. A HT-29 cell line that highly expressed CerbB-2 was selected using immunohistochemical method. The double-stranded siRNA targeting human CerbB-2 cDNA and the negative control fragment were cloned into pGenesil-1 vector, and after identification and sequence analysis, the constructed pGenesil-erbB2 plasmid was transfected into the selected HT-29 cell line. The pGenesil-erbB2 plasmid was successfully constructed and stably transferred into HT-29 cells. The transfection resulted in significant inhibition of Her-2 protein expression in the HT-29 cells, as shown by Western blotting. The pGenesil-erbB plasmid we constructed can be stably transfected into HT-29 cells to inhibit the expression of Her-2 protein, and can be useful in further studies of increasing the radiosensitivity of HT-29 cell lines.