| Part â… The clinicopathological association of FOXO3a overexpression in gastric cancer[Abstract] Objective:FOXO3a plays an important role in tumor progression and has been introduced as a negative prognostic marker in breast cancer. The aim of this study was to evaluate the frequency of FOXO3a overexpression and its relationship with clinicopathological variables in gastric cancer of Chinese population using tissue microarray. Methods:Paraffin blocks of150patients with gastric cancer treated by curative gastrectomy during a3-year period of2006-2008in Shanghai Zhongshan hospital were collected in tissue microarray and the expression of FOXO3a was investigated by immunohistochemical staining. FOXO3a status was stratified as "high" and "low" with both the intensity and extension of positive staining taken into account. The relationship between FOXO3a status and age, sex, tumor location, differentiation grade, the extent of tumor invasion(T), the extent of spread to lymph nodes (N), TNM stage and presence of vascular and neural invasion was analyzed.Results:150cases were evaluated, constituted of95male and41female with the average age of61.2years. In63.3%(95/150) of tumors, high expression of FOXO3a was found. FOXO3a was overexpressed in95gastric cancer tissues(63.3%), with increased FOXO3a positivity associated with the extent of rumor invasion(T), the extent of spread to lymph nodes (N), higher TNM stage and presence of vascular invasion, but no asscociation with age, sex, tumor location, differentiation grade and neural invasion was found. Conclusions:FOXO3a protein was frequently overexpressed in gastric cancer tissues and it was related to clinicopathological characteristics such as depth of invasion, lymph node metastasis, vascular invasion and TNM staging. It can also support the idea that FOXO3a is an unfavorable marker in gastric cancer. Part â…¡ Effect of abnormal expression of FOXO3a on proliferation, migration, invasion, and chemotherapeutic-agent sensitivity in gastric cancer cell line[Abstract] Objective:To investigate the effect of abnormal expression of FOXO3a on cell proliferation, migration, invasion, and chemotherapeutic-agent sensitivity in a gastric cancer cell line, AGS. Methods:Human gastric cancer cell line AGS was stably transfected with antisense FOX03a using Lentivirus-mediated transfection, followed by investigation of in-vitro growth assay, wound healing assay, and invasion assay. Protein expression levels of Cathepsin D and Cathepsin L were measured by Western blot analysis. The AGS-FOXO3a-shRNA cells and AGS-negative shRNA cells were cultured with different concentrations of Irinotecan, Oxaliplatin and Taxol for48hours, then inhibition rate were determined by MTT assay. IC50s and RIs were calculated. Apoptosis determined by flow cytometry were performed on48h after incubation with Irinotecan, Oxaliplatin and Taxol. Western blot analysis was performed on48h after incubation with the same three agents. Results:Our results indicated that transfection of FOXO3a-shRNA effectively reduced the FOXO3a mRNA and protein expression. The capacity of migration and invasion of AGS-FOXO3a-shRNA cells was markedly reduced in vitro, which was linked to decreased expression of Cathepsin D and Cathepsin L. MTT assay revealed significantly enhanced sensitivity to Irinotecan and Oxaliplatin in AGS-FOXO3a-shRNA cells compared with negative control. Apoptosis assay revealed significantly induced apoptosis after48h incubation of Irinotecan/Oxaliplatin in AGS-FOXO3a-shRNA cells, accompanied by increased expression of Caspase-3and decreased expression of PARP-1, but no significant difference in bcl-2, Bax, and Caspase-9expression was observed. Conclusions:Our results suggest that FOXO3a may promote cell migration and invasion, as well as mediate drug resistance to Irinotecan and Oxaliplatin. Downregulation of FOXO3a using shRNA could provide a novel therapeutic treatment. |
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