Background and purpose: ERCC2 gene silence by siRNA interference was observed in esophageal cancer cell line and it could change cell sensitivity to taxol. This study was to investigate the biological mechanism of paclitaxel-resistance in esophageal cancer cells. Methods: ERCC2 targeting siRNA (si-ERCC2) has been synthesized. The constructor were transfected into ERCC2 cell lines high-KYSE150(bigh expression of ERCC2) through lipofectamine. RT-PCR and flow cytometry (FCM) were used to detect the ERCC2 mRNA and protein expression levels. MTr assay was used to estimate the paclitaxel sensitivity of the cells. Results: In si-ERCC2 group, ERCC2 could not be detected and ERCC2 protein expression were reduced by 31.2%, 51.6% and 60.0%, respectively, 24,48,72 b after transfection. Paclitaxel IC_(50) value for si-ERCC2 group was 6.32±0.87 μg/mL, lower than the control group(49%). Conclusion: siRNA could successfully silence the target gene ERCC2 at the level of transcription and translation of the gene, the reduction of ERCC2 expression may reverse taxol resistance of the cells.

Objective To study the expression and clinical correlation of miR-141 in peripheral blood and tumor tissue in elderly patients with rectal cancer.Methods Rectal tumor tissue and tumor-adjacent normal tissues were taken in 75 cases of rectal cancer.The expression levels of miR-141 in peripheral blood and tumor tissue as well as tumor-adjacent normal tissues were determined by real-time polymerase chain reaction method.The correlation of miR-141 expression between peripheral blood and tumor tissue,and the correlation of peripheral blood miR-141 with clinicopathologic features and clinical prognosis were analyzed.Results (1) Compared with peripheral blood in the subjects undergoing normal physical examination or tumor-adjacent normal tissue in the patients with rectal cancer,the miR-141 expression level in peripheral blood and tumor tissue in the patients with rectal cancer was decreased significantly (P<0.01).(2) The cancer tissue miR-141 level in the patients with lymph node metastasis was positively correlated with peripheral blood miR-141 level (r=0.694,P<0.01),and cancer tissue miR-141 level in the patients without lymph node metastasis was positively correlated with peripheral blood miR-141 level (r=0.725,P<0.01).(3) The differences between peripheral blood miR-141 level with tumor stage,tumor differentiation degree and lymphatic metastasis had statistical significance (P<0.01).(4)The postoperative 6-month follow up displayed that among 75 cases,13 cases(17.33%) appeared replase/ metastasis,and peripheral blood miR-141 level was (2.64±0.34),which was significantly lower than that in the patents without replase/metastasis (P<0.01).Conclusion Expression variation trend of miR-141 in peripheral blood is similar to that in tumor tissue,which can reflect the clinicopathologic feature in the patients with rectal patients.