Effects Of Angiotensin ? On The Biological Behavior And Expression Of HIF-1? In Human Hepatocellular Carcinoma HEPG2 Cells

Objective:(1)To investigate the effects of angiotensin II(Ang II)and angiotensin ?type 1 receptor(ATl R)antagonists on the biological behavior and expression of hypoxia-inducible factor 1 alpha(HIF-1?)in human hepatocellular carcinoma HepG2 cells.(2)To explore the expression of HIF-1? of ATl R antagonist in model of nude mice bearing human HepG2 hepatocellular carcinoma.Methods: With HepG2 cells culture in vitro,Ang II of different concentrations(10-8 ~10-6mol/L)and ATl R antagonist candesartan were respectively treated after 24 hours,The effect of Ang? on the proliferation of HepG2 cells was detected by CCK-8method with every 12 hours until the 60 th hour.The invasive ability of human hepatocellular carcinoma HepG2 cells was detected by Transwell after 24 hours.The adhesion ability of human hepatocellular carcinoma HepG2 cells was detected by the cell adhesion assay after 24 hours.The expression of HIF-1? was detected by ELISA assay in human hepatocellular carcinoma HepG2 cells after 24 hours.The stable model of nude mice bearing human HepG2 hepatocellular carcinoma was divided randomly into 5 groups including the control group(0.9% sodium chloride),the low dose of candesartan group(5mg/kg/d),the medium dose of candesartan group(10mg/kg/d),the high dose of candesartan group(20mg/kg/d)and 5-fluorouracil group(25mg/kg/d).Nude mice were sacrificed with continuous feeding for two weeks,the hepatocellular carcinoma tissue in nude mice was collected at the 15 th day.RNA was extracted from the hepatocellular carcinoma tissue by RNA extraction kit.The expression of HIF-1? m RNA of the hepatocellular carcinoma tissue was detected by RT-PCR assay.The total protein of the hepatocellular carcinoma tissue was extracted.The expression of HIF-1? protein was detected by Western Blot.Results: Ang? can enhance the proliferation of human hepatoma HepG2 cells with the increases of time and concentration.With the Ang II concentration of 10-7mo1/L and the reaction time of 48 hours,the proliferative impact which could be suppressed by candesartan goes to the peak.Ang? can also promote the ability of invasion and adhesion of human hepatoma HepG2 cells and the expression of HIF-1?.With the increase of Ang II concentration,the above-mentioned parameters of human hepatoma HepG2 cells increased.When the concentration of Ang II was 10-7mol/L,the above-mentioned parameters of human hepatoma HepG2 cells reach its maximum value.but the Ang II concentration was further increased to 10-6mol/L,there was no significant difference on above-mentioned parameters compared with those of10-7mol/L of concentration in human hepatoma HepG2 cells(P>0.05).However,the difference was statistically significant compared with those of the control group(P<0.05).Candesartan could block above-mentioned function,and the difference was statistically significant(P<0.05).The results of RT-PCR and Western blot analysis showed that the level of m RNA and protein expression of HIF-1? decreased in nude mice with the increase of feeding dose in candesartan.There was statistically significant difference compared with those of control group(P<0.05).The expression of low dose group in candesartan was significant difference compared with those of the 5-FU group(P<0.05).the difference was statistically significant between those of the 5-FU group and those of the control group(P<0.05).The expression of low dose in candesartan was significantly different compared with those of the 5-FU group(P<0.05).Conclusions:(1)Ang II can promote the proliferation,invasion and adhesion of tumor cells and the expression of HIF-1?,which can be antagonized by AT1 R antagonists.(2)AT1R antagonist can inhibit the expression of HIF-1? in liver cancer tissue,and weaken the ability of hypoxia tolerance and angiogenesis.