Anticancer Activity And Mechanism Of Caffeic-acid Ge

Background:Cancer seriously threatens our lives and health.Cervical cancer is a kind of common malignant cancer of gynecology,which accounts for the most fatality in gynecology cancer.Chemotherapy is one of the most important approaches in clinic trials nowadays.More and more efforts are carried out recently to explore novel compounds that will prevent and treat malignant tumor.Organic germanium compound belongs to the metallic compounds,which has attracted scientist's focus for its broad-spectrum anti-tumor activity and low toxicity.Therefore,it is critical and urgent to search for new organic germanium compounds and study the profound mechanism to improve the treatment of human cancer.Objective:To evaluate the antitumor effect of Caffeic-acid Ge on tumor-bearing mice,to investigate its possible mechanisms in cellular,subcellcular aspects,and to evaluate its acute toxicity.Methods:Tumor growth inhibition activity of Caffeic-acid Ge was measured by murine U14 and H22 tumor models in vivo.Apoptosis morphological transformation of U14 and H22 cells induced by Caffeic-acid Ge was detected by electronic scan microscope,HE staining and MG-P staining.Alteration of cell cycle was analyzed by flow cytometer. Apoptosis-related protein level was determined by immunity histochemistry technology. MTT assay was applied to study the antitumor activities of Caffeic-acid Ge in U14 and H22 cell lines in vitro.Acute toxicity testing was applied to appraise the safety of Caffeic-acid Ge. Results:1.The results of U14 tumor bearing mice demonstrated that Caffeic-acid Ge exhibited high experimental therapeutic activity in inhibiting the growth of U14 cells, and the inhibition rate caused by 0.5,1,2 mg/kg Caffeic-acid Ge was 38.50%,47.17% and 64.02%,respectively(P<0.01).The results of H22 tumor beating tests approved that Caffeic-acid Ge exhibited high experimental therapeutic activity in inhibiting the growth of H22 cell,and the inhibition.rate caused by 0.5,1,2 mg/kg Caffeic-acid Ge was 37.4%,47.2%,64.0%,respectively(P＜0.01).The MTT results suggested that Cafffeic-acid Ge exhibited high antiproliferative activity in U14 cell lines with IC₅₀of 48.57μg/ml.The above results showed that Caffeic-acid Ge exhibited high antiproliferative activity in vivo and in vitro.2.There was no significant difference of spleen index and thymus index between Caffeic-acid Ge groups and NS group.There was no significant change on body weight of mice treated with Caffeic-acid Ge compared with NS group.Caffeic-acid Ge showed superiority compared with Cyclophosphamide,which had serious immunosuppressive effect.3.Caffeic-acid Ge could induce apoptosis in U14 and H22 cells detected by HE staining,MG-P staining histopathology and electronic microscope.U14 and H22 cells treated with Caffeic-acid Ge presented typical apoptosis characteristic in morphology, including crenate membrane,condensed nuclear and margination of nuclear chromation and cytoplasmic vacuolation.4.Flow cytometer results indicated that most of the U14 and H22 cells treated with Caffeic-acid Ge were arrested at the sub-G0/G1 phase and then were initiated into apoptosis.5.The results of immunity histochemistry technology indicated the expression of bcl-2 protein was down-regulated by Caffeic-acid Ge while bax protein was up-regulated in U14 and H22 tumor tissue(P＜0.05).6.Acute toxicity testing approved that Caffeic-acid Ge had no visible acute toxicity, and maximum tolerated drug dose was 8 g/kg. Conclusion:Caffeic-acid Ge was a potent agent against murine U14 and H22 tumo cells in vivo and in vitro without immunosuppressive action and visible acute toxicity.Caffeic-acid Ge could increase the expression of bax and decrease the expression of bcl-2 to induce apoptosis of U14 and H22 cells.