ABSTRACT
AIM: To construct pcDNA3.1-Egr.1p-p16 recombinant plasmid and investigate the expression of p16 in pancreatic cancer JF305 cells induced by radiation and the feasibility of gene radiotherapy for pancreatic carcinoma. METHODS: Human p16 cDNA was ligated to the downstream of Egr-1 promotor to construct pcDNA3.1-Egr.1p-p16 plasmid by restriction enzyme digested. The recombined plasmids were transfected into pancreatic cancer JF305 cells with lipofectamine. p16 mRNA level was detected by RT-PCR. The expression of p16 after different doses of X-ray radiation was detected by Western blot technique. Cell survival was assessed by clonogenic assays and cell viability was analysed by trypen blue exclusion. Flow cytometry was performed to study the apoptosis of JF305 cells. RESULTS: Restriction enzyme digestion showed the correctly constructed pcDNA3.1-Egr.1p-p16. The p16 expression in cells transfected with pcDNA3.1-Egr.1p-p16 induced by different doses of radiation was higher than that in the control group (P < 0.05). Eight hours after 2 Gy X-ray radiation, the expression reached its peak (87.00 ng/L), and was significantly higher than that in the control group (P < 0.0.5). Clonogenic analysis and trypan blue extraction test showed that the pcDNA3.1-Egr.1p-p16 transfer enhanced radiation-induced cell killing in p16-null JF305 cell lines. The induction of apoptosis was lower in combined transfection and irradiation group than that in irradiation alone. CONCLUSION: X-ray can induce the recombinant plasmid pcDNA3.1-Egr.1p-p16 expression in JF305 cells. The detection of dose and time provides an experimental basis for in vivo study in future.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p16/genetics , Cyclin-Dependent Kinase Inhibitor p16/metabolism , Gene Expression Regulation, Neoplastic/radiation effects , Genetic Vectors/genetics , Pancreatic Neoplasms/metabolism , Plasmids/genetics , Apoptosis/genetics , Apoptosis/radiation effects , Cell Line, Tumor , Cell Survival/genetics , Cell Survival/radiation effects , Dose-Response Relationship, Radiation , Humans , Pancreatic Neoplasms/pathology , RNA, Messenger/genetics , RNA, Messenger/metabolism , TransfectionABSTRACT
AIM: To determine the survival of advanced pancreatic cancer patients treated with intraoperative radiotherapy (IORT) combined with external beam radiation therapy (EBRT) following internal drainage (cholecystojejunostomy or choledochojejunostomy). METHODS: Eighty-one patients with advanced pancreatic cancer who received IORT combined with EBRT following internal drainage (ID) between 1996 and 2001 were retrospectively analyzed. Among the 81 patients, 18 underwent ID+IORT, 25 ID+IORT+EBRT (meanwhile, given 5-Fu 300 mg/m(2) i.v. drip, 2f/w), 16 EBRT, 22 had undergone simple internal drainage. The IORT dose was 15-25Gy in a single fraction. The usual EBRT dose was 30-40Gy with a daily fraction of 1.8-2.0 Gy. RESULTS: The complete remission rate, partial remission rate of patients with backache and abdominal pain treated with ID+IORT were 55.5%, 33.3% respectively. Alleviation of pain was observed 2 or 3 wk after IORT. The median survival time (MST) of ID+IORT group was 10.7 mo. The pain remission rate of patients treated with ID+IORT+EBRT was 92%, and their MST was 12.2 mo. The MST of patients treated with EBRT and simple internal drainage was 5.1 mo and 7.0 mo, respectively. The survival curve of ID+IORT group and ID+IORT+EBRT group was significantly better than that of EBRT group (P<0.05). The difference between the ID+IORT+EBRT group and ID group was significant (P<0.05). CONCLUSION: IORT combined with EBRT following internal drainage can alleviate pain, improve quality of life and prolong survival time of patients with advanced pancreatic cancer.