siRNA blocking the RAS signalling pathway and inhibits the growth of oesophageal squamous cell carcinoma in nude mice

The aim of this study was to study RAS‐siRNA blocking RAS pathway and suppressing cell growth in human oesophageal squamous cell carcinoma in nude mice. The methods in this study was to construct RAS‐siRNA expression vector, establish 40 oesophageal squamous cell carcinoma xenograft animal models and divided them into five groups: control group, siRNA control group, RAS‐siRNA group, paclitaxel group and RAS‐siRNA and paclitaxel group. We observed tumour growth in nude mice, studied histology by HE staining, tumour growth inhibition by TUNEL assay and detected the RAS, MAPK and cyclin D1 protein expression by immunohistochemistry and western blot. We have obtained the following results: (i) successfully established animal models; (ii) nude mice in each group after treatment inhibited tumour volume was significantly reduced compared with the control group (p < 0.05); (iii) compared with the control group, the number of apoptotic cells were significantly increased in the siRNA control group and the RAS‐siRNA group, and the number of apoptosis cells in the paclitaxel and RAS‐siRNA group is significantly most than the paclitaxel group and RAS‐siRNA group (p < 0.05); and (iv) after treatment, RAS, MAPK and cyclin D1 expression in five groups was decreasing gradually. After adding paclitaxel, the protein expression in the paclitaxel and RAS‐siRNA group was significantly lower than that of paclitaxel group, negative control and paclitaxel group (p < 0.05). We therefore conclude that RAS‐siRNA can block the RAS signal transduction pathway, reduce the activity of tumour cells, arrest tumour cell cycle, promote apoptosis, inhibit cell proliferation and increase tumour cell sensitivity to chemotherapeutic drugs. Copyright © 2014 John Wiley & Sons, Ltd.