Low dosage 5-fluorouracil increases the transfection efficiency of Ad/VEGF-A in mouse lung carcinoma cell line LA795 and inhibits tumor growth.
OBJECTIVE
Adenovirus vectors were widely used in gene therapy for tumors. We used adenovirus vector to transfer small interfering RNA (siRNA) against vascular epithelium growth factor A (VEGF-A) molecules to mouse lung adenoma LA795 cells and used low dose of chemotherapeutic drugs to further elevate the infection efficiency of adenovirus vector in and therapeutic effect of RNAi on tumor cells.


METHODS
LA795 cells were infected by Ad/EGFP and treated with different dosages of gemcitabin, epirubicin, cisplatin, or 5-fluorouracil (5-FU). Cells were observed under fluorescence microscope continuously using green fluorescent protein (GFP) as the reporter gene. The percentage of GFP-positive cells and fluorescent intensity were tested by flow cytometry to determine optimum concentrations of drugs. Ad/siVEGF-A containing VEGF-A siRNA was constructed. Real-time PCR and ELISA were applied to measure the expression level of VEGF-A after LA795 cells were infected by Ad/siVEGF-A and treated with 5-FU. The combination of Ad/siVEGF-A and 5-FU was also applied in treating subcutaneous tumor in mice.


RESULTS
Low dose of 5-FU elevated the Ad/EGFP infection in LA795 cells significantly, and also enhanced the effect of Ad/siVEGF-A in down-regulating VEGF-A mRNA and protein levels in tumor cells. When used in tumor in vivo, the combination strategy repressed tumor growth effectively.


CONCLUSIONS
Low dose of 5-FU can enhance the capability of adenovirus infecting tumor cells and promote the efficiency of gene therapy by adenovirus.
Wang
Feng
F
Experimental Center, Affiliated First People's Hospital, Shanghai Jiaotong University, Shanghai 200080, PR China.
Li
Hui-Ming
HM
Chen
Xia-Fang
XF
Xie
Kuang-Cheng
KC
Huang
Qian
Q
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005472:Fluorouracil / Q000008:administration & dosage / Q000494:pharmacology*; D015316:Genetic Therapy; D005822:Genetic Vectors; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics*; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology
D000964:Antimetabolites, Antineoplastic; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; D005472:Fluorouracil