Study On Therapy Of Liver Cancer Through Polylactic Acid-Glycolic Acid Nanoparticles (PLGA) Carried With Antisensenucleic Acid Of Human Telomerase Reverse Transcriptase (hTERT)

Telomerase can synthesize telomere by using its RNA and add it to the end of the chromosome, which can compensate for the loss of the telomere by mitosis and prevent cells from aging and apoptosis, so cells can cancerate and become cancerous cells. Positive rate of telomere in malignant tumors and immortalization cells can achieve to 80% to 90%, while in benign tumors and normal tissues is lower than 4%.Antisensenucleic acid technique is an attracting method in gene therapy. By using this technique, antisensenucleic acid of oncogene mutant, antioncogen mutant and gene of autocrine growth factor and its receptor can be designed. At transcription level or translational level, antisensenucleic acid can block abnormal genes, which makes their products can't be expressed or be expressed at low level. At the end, the tumor will be inhibited.Telomerase as a target and by using antisensenucleic acid technique, malignant tumors might be treated and the effect might be good with less side effects.Although research on antisensenucleic acid technique has been done for more than 20 years, antisensenucleic acid technique can't be used in the clinic. One of the problems is DNA carrier. Traditional DNA deliver system has two methods: virus vector mediated system and non virusvector mediated system. Virus vector mediated system is effective, but because of viral toxicity and immunogenicity, its appliance has been limited. Although non virus vector mediated system has no ability of viral toxicity and immunogenicity, its transmission efficiency is not better than virus vector mediated system. The efficiency of liposome as a non virus vector is also low. To promote the transmission efficiency of non virus vector mediated system becomes the key problem to treat tumors by using antisensenucleic acid technique.With the development of nanotechnology, non virus vector mediated system based on nanotechnology might solve the problem and achieve safe and high effective DNA transmission and can be used to study gene expression and its function and their appliance in clinic.This study used ploylactic acid -glycolic acid nanoparticles (PLGA) as antisensenucleic acid carrier to treat hepatic carcinoma. And I hope that by combining nanotechnology and antisensenucleic acid technique, the effect to treat hepatic carcinoma might be promoted.This study included the following : (J) study on preparation technology of PLGA nanoparticles; (2) characteristic and bio-effectiveness of PLGA nanoparticles carrying antisense nucleate plasmid of telomerase; (3) the transfection efficiency and effect of PLGA nanoparticles carrying antisense nucleate plasmid of telomerase on hepatic carcinoma cell telomerase and hepatic carcinoma growth in vitro,? effect of PLGA nanoparticles carrying antisense telomerase RNA on nude mouse transplanted hepatic carcinoma.This study showed that size of PLGA nanoparticles carrying antisense telomerase RNA were even and their size changed in a narrow range, their stability and biocompatibility were good. PLGA nanoparticles as vector could prevent antisense telomerase RNA from being degraded by nuclease.Compared with liposome mediated antisense telomerase RNA transfection efficiency (42%), PLGA nanoparticles mediated antisense telomerase RNA transfection efficiency was higher and achieved 61%.Compared with bland group, the bioactivity of telomerase and growth of the hepatic carcinoma in liposome carrying antisense telomerase RNA and PLGA nanoparticles carrying antisense telomerase RNA decreased significantly and apoptosis of hepatic carcinoma cells increased( p <0.05). There was significant difference ( p <0.05). This study showed that the inhibition on hepatic carcinoma cells of PLGA nanoparticles carrying antisense telomerase RNA was stronger and that inducing tumor cells apoptosis was important in antisense telomerase nucleic acid treating tumors.In this study, I studied the effect of PLGA nanoparticles carrying antisense telomerase RNA on nude mouse transplanted hepatic carcinoma. The result showed that PLGA nanoparticles carrying antisense telomeraseRNA could delayed the tumor development and inhibit the growth of the tumor. And inhibitory rate achieved to 50.5%. The formation of the transplanted hepatic carcinoma was also delayed significantly. The cells increased at Gl, but decreased at G2 and S, which interfered the cells transforming from Gl to S period. The result indicated that except for inducing tumor cells apoptosis, inducing tumor cells differentiation was important in inhibitory effect of antisense telomerase RNA on tumor cells.Through this study, I consider that PLGA nanoparticles might be a useful non virus vector, the efficiency is better than that of liposome. By using PLGA nanoparticles as vector of antisense telomerase nucleic acid, inhibitory effect of antisense telomerase nucleic acid on hepatic carcinoma is significantly increased and therapeutic effect on hepatic carcinoma can be increased.This study might be a base for other gene drugs and other treatment on malignant tumors.