The cooperative effect of p53 and Rb in local nanotherapy in a rabbit VX2 model of hepatocellular carcinoma

Abstract

Shengli Dong,1 Qibin Tang,2 Miaoyun Long,3 Jian Guan,4 Lu Ye,5 Gaopeng Li6 1Department of General Surgery, The Second Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, Shanxi Province, 2Department of Hepatobiliopancreatic Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, 3Department of Thyroid and Vascular Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, 4Department of Radiology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, 5Infection Department, Guangzhou No 8 Hospital, Guangzhou, Guangdong Province, 6Department of Ultrasound, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, People's Republic of China Background/aim: A local nanotherapy (LNT) combining the therapeutic efficacy of trans-arterial embolization, nanoparticles, and p53 gene therapy has been previously presented. The study presented here aimed to further improve the incomplete tumor eradication and limited survival enhancement and to elucidate the molecular mechanism of the LNT. Methods: In a tumor-targeting manner, recombinant expressing plasmids harboring wild-type p53 and Rb were either co-transferred or transferred separately to rabbit hepatic VX2 tumors in a poly-L-lysine-modified hydroxyapatite nanoparticle nanoplex and Lipiodol® (Guerbet, Villepinte, France) emulsion via the hepatic artery. Subsequent co-expression of p53 and Rb proteins within the treated tumors was investigated by Western blotting and in situ analysis by laser-scanning confocal microscopy. The therapeutic effect was evaluated by the tumor growth velocity, apoptosis and necrosis rates, their sensitivity to Adriamycin® (ADM), mitomycin C, and fluorouracil, the microvessel density of tumor tissue, and the survival time of animals. Eventually, real-time polymerase chain reaction and enhanced chemiluminescence Western blotting were used to investigate the expressive changes of important genes related to the therapy. Results: The administration procedure proved safe for the rabbits' liver function, the p53 plus Rb LNT showed significantly better antitumoral effect and lower expression of malignant genes than the p53 or Rb LNT, although no significant difference was observed in animal survival when the p53 plus Rb LNT was compared with the p53 LNT. Conclusion: Rb works synergistically with p53 in combined therapy mediated by a poly-L-lysine-modified hydroxyapatite nanoparticle nanoplex to augment the antitumoral effect through the downregulated expression of important genes related to apoptosis, necrosis, growth, differentiation and multidrug resistance of tumor cells. LNT with p53 and Rb is potentially an effective antitumor therapy for hepatocellular carcinoma. Keywords: nanoparticles, gene-transfer techniques, targeting, combined therapy