Abstract
The aim of this study was to establish an animal model of HepG2 liver cancer in nude mice, and to inhibit the expression of MTH1 gene in tumor cells by siRNA interference. To study the therapeutic effect of down-regulation of MTH1 expression on HepG2 tumor in nude mice, and to provide a new strategy for the treatment of HCC. Methods: Human HepG2 cells were cultured and transplanted tumor models were established under the armpit of right forelimb of nude mice. The successful nude mice were randomly divided into two groups: control group (CT) and siRNA transfection group (MTH1). The tumor volume of each group of nude mice was consistent. This experiment was mainly conducted by injecting siRNAs into tumor-bearing nude mice and transfection reagents in vivo. The survival time and living condition of nude mice were observed. The tumor inhibition was evaluated by measuring the volume and weight of solid tumor in nude mice. After the administration, The expression of mth1 and its related genes were detected by qPCR to determine the effect of QPCR on the mRNA expression of each gene. The relative expression of mth1 and related proteins in tumor tissues was detected by Elisa and Western blotting. The effect of siRNA on the protein level of each gene was evaluated by calculating the gray value and comparing the od value. Results: The animal model of HepG2 liver cancer in nude mice was successfully established, and the tumorigenesis rate was 100%. The siRNA transfection group had significant anti-tumor effect and significantly inhibited the growth of tumor cells. Survival rate of nude mice in each group was 100%. Compared with the control group, In the transfected group, the expression of mth1 mRNA and protein decreased significantly in the tumor tissues. The expression of caspase-3 protein was significantly increased in the transfected group. Conclusion: SiRNA-MTH1 can effectively silence the expression of MTH1 gene. Down-regulation of mth1 gene expression by siRNA can inhibit the growth, proliferation and apoptosis of HepG2 tumor cells.
Highlights
Primary liver cancer (HCC) is one of the most common malignant tumors in the world, its morbidity and mortality are among the highest in the world[1]
The best-known small, non-coding RNA that suppresses gene expression falls into three broad categories: Small RNAs miRNAs, small interference RNAs siRNAs, and interactions with PIWI protein RNAs piRNAs[7,8,9]
The mature forms of these RNAs are about 20-30 nucleotide nts, which are associated with many ago protein superfamily members and play a key role in RNA interference RNAi pathway[10,11,12]
Summary
Primary liver cancer (HCC) is one of the most common malignant tumors in the world, its morbidity and mortality are among the highest in the world[1]. Surgical treatment is the best method for the treatment of liver cancer[2]. Because most patients were diagnosed only in the late stages of the disease, they missed the best time for surgical treatment. The search for new therapeutic tools and drug targets is essential for the treatment of liver cancer[3]. MTH1 (mutT homolog1) is a homologous enzyme of MutT, which is widely distributed in the nucleus and mitochondria and participates in DNA damage and repair. Especially in the repair of DNA damage of tumor cells. MTH1 is considered to be an important repair gene in tumor cells[5,6]
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