The Effect Of PESV On The Expression Of VEGF、HIF-1α And PTEN In Angiogenesis Of Experimental Lung Cancer

Research backgroundsLung cancer is the most common malignant tumor which is primarily attack thelungs，the most majority of lung cancer originated in the bronchial epithelium.Themortality of it has rised to111.85percent since the1970s to the1990s,which is thehighest of all malignant tumors. Non-small cell lung cancer is the most commonpathological type of lung cancer, accounts for80percent of the total number ofit.Nowdays the alternative treatment method of it is limited, results in high mortalityand the average five years of survival rate is less than15percent.It is a quite active research domain for developing a traditional Chinese drugwith anti-angiogenic effects which targets the tumor vasculars. It is one of the keyissues to be solved in tumor anti-angiogenesis therapy of looking for a drug withtargeted regulatory function aiming at various angiogenic factors, because thesefactors interact each other in tumor angiogenesis process.Traditional Chinesemedicine and Chinese drugs possess its unique advantages in tumor anti-angiogenictherapy. Polypeptide extract from scorpion venom(PESV) contains effectiveanti-tumor ingredients which is extracted and purified from Buthus martensiiKarsch in our laboratory and it has a variety of biological activities.Currentexperiment studies have demonstrated that it could inhibited the proliferation ofumbilical vein endothelial cells of human and the angiogenesis of chicken embryo allantois membrane.But its mechanisms of anti-angiogenesis haven’t fullyelucidated.In this study, the mechanisms of PESV on anti-tumor angiogenesisthrough influencing the expression of VEGF、HIF-1α and PTEN will be discussed byvivo and vitro. ObjectiveTo reveal the mechanisms of PESV on anti-tumor angiogenesis and seek thenew strategy of Chinese drugs to treat non-small cell lung cancer through observingthe effects of PESV on the expression of VEGF、HIF-1α and PTEN in tumorangiogenesis and the cytotoxicities on A549cell in vitro；observing the expressioneffects in gene and protein levels of VEGF、HIF-1α and PTEN in tumor tissue andthe growth effects of transplanted tumor of nude mice in vivo.Methods1.MTT method was used to detect the effects of PESV on cell growth andproliferation of A549and the cell inhibition rate of each drug concentration wascalculated according to the absorbance value.Downstream experiments devidedA549cells which was in exponential phase into control group、PESV low dosegroup、PESV middle dose group and PESV high dose group which was based onIC50value，immunocytochemistry and Western blot methods were applied to detectthe protein expression changes of VEGF、 HIF-1α and PTEN after PESVintervention.2.Transplanted tumor of nude mice models were established and randomlydivided into three groups：tumor-bearing control group、high dose goup and low dosegoup.PESV was given by gavage method once every other day,control group wasgiven an equal volume of normal saline.Tumor volume were measured and tumorinhibitory rate were calculated to draw the tumor volume growth curves and observethe inhibitory effect of PESV on tumor growth.3.RT-PCR and Western blot methods were applied to detect the expressionlevels of angiogenesis regulatory factors VEGF、HIF-1α and PTEN in each treatmentgroup of transplantable tumor of nude mice.Results1.The effects of PESV on growth and proliferation of A549cells The value-added inhibition effect on A549was significant when the drugconcentrations ranged from25μg/mL to200μg/mL,compaired to the negativecontrol group, p<0.01. The differences of multiple comparisons between25μg/mLand200μg/mL were significant, p<0.01,the totality was in a dose-independent matter,r=0.966，p<0.01.2.The effects of PESV on the expression of VEGF、HIF-1α and PTEN in A549cellsImmunocytochemistry results showed that the expression of VEGF and HIF-1αwere significantly reduced in A549cells after PESV intervention，the comparisonsamong groups were significant(p<0.05or p<0.01).The expression of PTEN was in aescalated tendency, the comparisons among groups(p<0.05or p<0.01).The Westernblot results were generally consistent with it.3.The growth effects of PESV on transplantable tumor of nude mice.The tumor growth of PESV high dose group was significantly inhibitedcompared with the tumor-bearing control group after PESV intervened21days,thetumor inhibitory rate was up to40.36%(p<0.01)；the tumor inhibitory rate of PESVlow dose group was20.15%,the difference was also statistically significant(p<0.05).4.The effects of PESV on the expression of VEGF、HIF-1α and PTEN in lungcancer tumor tissuesRT-PCR test results showed that the expression levels of VEGF and HIF-1αwere remarkably reduced in tumor tissues after PESV intervention，the comparisonsamong groups(p<0.05or p<0.01). The expression of PTEN was remarkablyescalated, the comparisons among groups(p<0.05or p<0.01). The Western blotresults were generally consistent with it.Conclusions1.PESV can inhibit the growth of lung cancer cells and transplanted tumor ofnude mice.2.PESV can influence the expression of angiogenic factors VEGF、HIF-1α and PTEN in lung cancer tumor cells and tissues，which may be the anti-angiogenicmechanisms of it.