The Significance Of HER2/neu And The Effect Of Targeted Drug On The Esophageal Squamous Carcinoma

Objective:1To study HER2/neu protein and gene amplification in esophageal squamous cell carcinoma(ESCC) and to investigate the relationship between the expression/amplification of HER2/neu and the clinical characteristics of esophageal squamous cell carcinoma.We hope test our hynothesis that HER2/neu might be a prognosis factor and potential candidate for new adjuvant therapies which involve the use of humanized monoclonal antibodies.2To study the effects of Herceptin on the proliferation and apoptosis of esophageal squamous carcinoma cells EC109in vitro, to explore its perliminary mechanism and to evaluate the validity of Herceptin on the treatment of ESCC.Methods:1The clinical data of145patients admitted in Renmin Hospital of Wuhan University, from2000to2010, were reviewed. The HER2/neu protein expression and gene status in145esophageal carcinomas were evaluated using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Categorical variables were compared by the Pearson chi-square test or Fisher’s exact test and the survival rate was calculated by the Kaplan-Meier method and the log-rank test.2The protein and mRNA expression of HER2/neu in EC109were measured by immunofluorescence staining and RT-PCR. ESCC cells were treated with Herceptin, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylterrazolium bromide) assay was used to measure the survival and growth inhibition rate of EC109; Flow Cytomtry and Hoechst33258methods were used to maesure the apoptosis of EC109; Western blot was used to measure the effects of Herceptin on the expression proteins in two main HER2/neu-mediated signal pathways:Ras/MAPK and PI3K/Akt signal pathways. One-way AN OVA were used to determine the stastistical differrence.Results:1Compared to normal esophageal epithelium(23/95,24.2%), HER2/neu protein was overexpressed in most esophageal squamous carcinoma tissues(60/145,41.4%),of which45(31.0%) were2+and15(10.4%) were3+. The rate of HER2/neu gene amplification by FISH detection was16.6%. HER2/neu overexpression associated significantly with HER2/neu gene amplification. Taken FISH detection as gold standard, the sensitivity, specificity, positive predictive and negative predictive were87.5%,67.8%,35.0%and96.5%.2There was a high correlation between the overexpression of HER2/neu and the differentiation of the carcinoma(P<0.05); The HER2/neu gene amplification associated significantly with the differentiation of the carcinoma and the tumor stage(P<0.05). According to univariate analysis, there was a significant difference in survival rates when cases with and without HER2/neu overexpression or amplification were compared(P<0.05).The survival analysis showed that patiens with HER2/neu overexpression/amplification exhibited poor mean survival rates.3MTT assay showed that Herceptin can significantly inhibit the growth of esophageal squamous cell carcinoma cells with HER2/neu overexpression. The ability of inhibition can significantly increased with increasing concentration and time, which showed a dose-time-dependent rule. In addition, flow cytometry and Hoechst33258method confirmed Herceptin can induce apoptosis of esophageal squamous cell carcinoma EC109cells, which show a dose-dependent manner.4Western blot examined the expression of some important related molecules in tow HER2/neu mediated Ras/MAPK and PI3K/Akt pathway,such as HER2/neu、Ras、Akt、pAkt and p27. The results showed that Herceptin can significantly reduced the level of HER2/neu, Ras and pAKT expression, increased the level of the level of p27expression,which can prevent the actvation of several intracellular signaling cascades.Conclusion:1Most ESCC patients had HER2/neu overexpression and amplification. Scince there is a high correlation between HER2/neu overexpression and amplification, IHC testing HER2/neu protien overexpression in ESCC sometimes can substitute for FISH test, which can provide guidance of prognosis and treatment.2HER2/neu amplification/overxepression may be used as an independent prognostic factor in esophageal squamous cancer patients, and patients with HER2/neu amplification/overxepression might be potential candidates for new adjuvant therapies which involve the use of humanized monoclonal antibodies. HER2/neu protein overexpression and gene amplification to determine the prognosis of patients with esophageal squamous cell carcinoma have some clinical significance. HER2/neu overexpression may be used as a clinical indicator in patients with esophageal squamous cell carcinoma targeted therapy.3Herceptin can significantly inhibit the proliferation of esophageal squamous cell carcinoma EC109cells and induce its apoptosis, which showed a dose-time-dependent rule.4Herceptin could inhibit the proliferation of esophageal squamous cell through blocking HER2/neu-mediated Ras/MAPK and PI3K/Akt signaling pathway. This study was conducted with a view toward the future introduction of Herceptin therapy for the treatment of ESCC patients.