Increase of the therapeutic effect by treating nasopharyngeal tumor with combination of HER-2 siRNA and paclitaxel

Abstract

Abstract. Therapeutic agents targeting HER-2/neu have been intensively addressed over the past decades. Previously, we reported that HER-2 synthetic small interfering RNA (HER-2 siRNA) could suppress the growth of human nasopharyngeal KB tumor xenografts by intratumoral injection with lipidbased nanoparticles; however, complete regression of the tumor was not achieved. In this study, we investigated antitumor activity by RNA interference in combination with paclitaxel (PTX) for KB cells using HER-2 siRNA and HER-2 short hairpin RNA-expressing plasmid DNA (HER-2 shRNA pDNA). Suppression of HER-2 expression by siRNA or shRNA pDNA caused significant reduction of proliferation by inducing apoptosis and enhancing the sensitivity for PTX in HER-2 positive KB cells. Interestingly, an HER-2 antibody trastuzumab could not increase the antitumor effect by PTX in KB xenografts. Combination therapy by intratumoral injection of HER-2 siRNA or HER-2 shRNA pDNA with PTX significantly inhibited the tumor growth of xenografts compared with each therapy used individually. In particular, HER-2 shRNA pDNA plus PTX largely extended the mean survival days compared with HER-2 siRNA plus PTX. Collectively, these findings suggest that HER-2 shRNA-based combined therapy with PTX could be a novel strategy to inhibit the progression of HER-2-positive cancer.

Emerging molecular targets in the treatment of nasopharyngeal carcinoma

“…In nude mice xenograft models, direct injection of 188 Relabeled trastuzumab into tumors expressing HER2/neu showed increased distribution in the nasopharynx compared with the rest of the body [55]. More recently, direct intratumoral injection of small interfering RNA (HER2 siRNA) with lipidbased nanoparticles in combination with paclitaxel has shown antitumor effects in xenografts [56]. There have, however, been no prior clinical studies of trastuzumab in NPC.…”