Original Article
Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Dec 14, 2009; 15(46): 5813-5820
Published online Dec 14, 2009. doi: 10.3748/wjg.15.5813
NT4(Si)-p53(N15)-antennapedia induces cell death in a human hepatocellular carcinoma cell line
Li-Ping Song, Yue-Ping Li, Ning Wang, Wei-Wei Li, Juan Ren, Shu-Dong Qiu, Quan-Ying Wang, Guang-Xiao Yang
Li-Ping Song, Ning Wang, Wei-Wei Li, Juan Ren, Department of Radiotherapy Oncology, First Hospital, Medical School of Xi’an Jiao Tong University, Xi’an 710061, Shaanxi Province, China
Yue-Ping Li, Center for Reproductive Medicine, Affiliated Hospital of Hainan Medical College, Haikou 570102, Hainan Province, China
Shu-Dong Qiu, Department of Anatomy and Histology & Embryology, Medical school of Xi’an Jiao Tong University, Xi’an 710061, Shaanxi Province, China
Quan-Ying Wang, Guang-Xiao Yang, Xi’an Huaguang Bioengineering Co, Xi’an 710061, Shaanxi Province, China
Author contributions: Song LP designed the research; Song LP, Li YP, Li WW and Wang N performed the research; Qiu SD, Wang QY and Yang GX provided the new reagents, analytical tools, and analyzed the data; Song LP, Li YP, Wang N, Li WW and Ren J wrote the paper.
Supported by The National Natural Science Foundation of China, No. 30471942 and the Key Science Research Project of Shaanxi Province, No. 2004k11-G3
Correspondence to: Li-Ping Song, MD, PhD, Department of Radiotherapy Oncology, First Hospital, Medical School of Xi’an Jiao Tong University, Xi’an 710061, Shaanxi Province, China. slpwn@126.com
Telephone: +86-29-85324029 Fax: +86-29-85323187
Received: September 20, 2009
Revised: November 5, 2009
Accepted: November 12, 2009
Published online: December 14, 2009
Abstract

AIM: To construct the recombinant lentivirus expression plasmid, pLenti6/V5-NT4 p53(N15)-antennapedia (Ant), and study its effect on HepG2 cells.

METHODS: Plasmid pLenti6/V5-NT4 p53(N15)-Ant was constructed incorporating the following functional regions, including signal peptide sequence and pro-region of neurotrophin 4, N-terminal residues 12-26 of p53 and 17 amino acid drosophila carrier protein, Ant. Hepatocellular carcinoma (HepG2) cells were used for transfection. 3-[4,5-dimethyl-thiazol-2yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, transmission electron microscopy (TEM) and flow cytometric analysis (FCM) were employed to investigate the effects of LV-NT4(Si)-p53(N15)-Ant in vitro on HepG2 cells. In vivo experiment was also performed to investigate the inhibitory effect of LV-NT4(Si)-p53(N15)-Ant on tumor growth in nude mice.

RESULTS: LV-NT4(Si)-p53(N15)-Ant significantly suppressed the growth of HepG2 cells. MTT assay showed that the growth of HepG2 cells was mucj more significantly inhibited by LV-NT4(Si)-p53(N15)-Ant than by LV-EGFP. The inhibition rate for HepG2 cell growth in the two groups was 46.9% and 94.5%, respectively, 48 h after infection with LV-NT4(Si)-p53(N15)-Ant, and was 33.9% and 95.8%, respectively, 72 h after infection with LV-NT4(Si)-p53(N15)-Ant (P < 0.01). Light microscopy and TEM showed morphological changes in HepG2 cells infected with LV-NT4(Si)-p53(N15)-Ant, but no significant changes in HepG2 cells infected with LV-EGFP. Changes were observed in ultra-structure of HepG2 cells infected with LV-NT4(Si)-p53(N15)-Ant, with degraded membranes, resulting in necrosis. LDH release from HepG2 cells was analyzed at 24, 48, 72 and 96 h after infection with LV-NT4(Si)-p53(N15)-Ant and LV-EGFP, which showed that LDH release was significantly higher in LV-NT4(Si)-p53(N15)-Ant treatment group (682 IU/L) than in control group (45 IU/L, P < 0.01). The longer the time was after infection, the bigger the difference was in LDH release. FCM analysis showed that LV-NT4(Si)-p53(N15)-Ant could induce two different kinds of cell death: necrosis and apoptosis, with apoptosis being the minor type and necrosis being the main type, suggesting that LV-NT4(Si)-p53(N15)-Ant exerts its anticancer effect on HepG2 cells by inducing necrosis. The in vivo study showed that LV-NT4(Si)-p53(N15)-Ant significantly inhibited tumor growth with an inhibition rate of 66.14% in terms of tumor size and weight.

CONCLUSION: LV-NT4(Si)-p53(N15)-Ant is a novel recombinant lentivirus expression plasmid and can be used in gene therapy for cancer.

Keywords: Gene therapy; Lentivirus vector; Anticancer; Necrosis; LV-NT4(Si)-p53(N15)-Ant; Hepatocellular carcinoma cell line