ABSTRACT
OBJECTIVE: To investigate the relationship between p16 expression and cell proliferation and prognosis in gastric cancer patients. METHODS: Gastric cancer cell lines SGC-7901, MKN45, MKN28, human embryonic kidney cell line HEK293, human fibroblast cell line MRC-5, and surgical specimens of gastric carcinoma and adjacent normal gastric mucosa from 65 patients were included in this study. RT-PCR, MTT and FCM assays were used to detect p16 expression in gastric cancer cell lines and surgical specimens of gastric cancer. MTT assay was used to determine cancer cell viability and FCM to detect cell cycle. Kaplan-Meier survival curve and Log-Rank statistics were used to analyze the relationship between p16 expression and survival of petients with gastric cancer. RESULTS: Gastric cancer cell lines were mostly negative for p16 expression, and p16 was re-expressed after the cells transfected with p16 gene by adenovirus AdCMV-p16. p16 re-expression resulted in the decrease of cancer cell viability and cancer cell cycle arrest with increased G(1) phase and decreased S phase. p16 expression in cancer specimens was 32.3% (21/65), significantly lower than the 81.5% (53/65) in normal mucosa (χ(2) = 32.124, P < 0.001). The disease-free survival was significantly shorter in p16-negative patients than that in p16-positive patients (P < 0.01), but not the overall survival (P > 0.05). p16 expression was significantly correlated with differentiation and lymph node metastasis, but not significantly correlated with sex, age, tumor size or invasion depth of the gastric cancer. CONCLUSIONS: p16 gene is important for cancer cell proliferation. The inactivation gives cancer cells a high activity for proliferation and metastasis, and then influences the disease-free survival of gastric cancer patients.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p16/metabolism , Genes, p16 , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Adenoviridae/genetics , Adult , Aged , Cell Cycle Checkpoints , Cell Line, Tumor , Cell Proliferation , Cell Survival , Cyclin-Dependent Kinase Inhibitor p16/genetics , Disease-Free Survival , Female , Gene Expression Regulation, Neoplastic , Humans , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Invasiveness , RNA, Messenger/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Survival Rate , TransfectionABSTRACT
Gene therapy is an important means for the comprehensive treatment of pancreatic cancer. Challenges associated with gene therapy include control of vector security and effective genetic screening. In this paper, a CEA promoter-regulated oncolytic adenovirus vector was constructed. The reporter gene assay demonstrated that the viral vector was confirmed to have tumor-specific replication features. In vitro cytology studies showed that the CEA promoter regulated the proliferation of the adenovirus vector carrying the Hsp70 gene (AdCEAp-Hsp70), which significantly increased the expression levels of Hsp70 in the CEA-positive pancreatic cancer cells, resulting in an overall reduction in the survival of cancer cells. In the human pancreatic cancer Panc-1 xenograft model in immune deficient nude mice, the CEA promoter-regulated adenovirus AdCEAp-Hsp70 significantly inhibited tumor growth. In the rat pancreatic cancer DSL-6A/C1 xenograft model in rats, the viral proliferation and high expression levels of Hsp70 promoted the interstitial infiltration of CD4+, CD8+ and gamma/delta T cells into tumors, induced host secretion of the cytokines TGF-ß, INF-γ, and IL-6 and had a dual anti-tumor effects that completely inhibited the growth of pancreatic cancer. The results demonstrated that the oncolytic adenovirus under the control of CEA promoter provides additional assurances regarding the safety and efficiency of cancer gene therapy. This gene therapy model improves anti-cancer efficiency and has broad applications and developmental prospects.
