Design, Synthesis, And Evaluation Of Gambogic Acid Biotin Conjugates As Anti-tumor Agents In Vitro

The incidence of malignant tumors is increasing in china,which seriously affects human's quality of life and life expectancy.Therefore,it is very important to develop the safe and effective anti-tumor drugs.Currently,the anticancer drugs are divided into the traditional anticancer drugs and novel anticancer drugs.The traditional anticancer drugs mainly include the agents directly acting on DNA,drugs interfering with DNA synthesis,antimitotic drugs.However,the antineoplastic effects of these drugs are stronger,but there are many shortcomings such as lack of selectivity and side effects.As a kind of target anti-tumor drugs,the novel anti-tumor drugs are worth of further developing due to their higher selectivity and lower side effects.In general,there are divided into organ targeting,cell targeting and molecular targeting,Gambogic acid is one of the effective active ingredients of the traditional Chinese medicinal Garcinia cambogia.Recently,the studies have shown that gambogic acid has inhibitory effects on human breast cancer cells,human hepatoma cells,human promyelocytic leukemia cells,human nasopharyngeal carcinoma cells,human gastric cancer cells and human lung cancer cells.About the anticancer mechanism of gambogic acid,it included the induction of tumor cell apoptosis,inhibition of cell cycle,affecting oncogenes,inhibiting cancer cell metastasis and inhibiting angiogenesis.By up-regulating the expression level of caspase-9 and caspase-10,the expression of gene regulatory protein(P53 protein)was up-regulated,the expression of human double-dimer protein 2 was down-regulated,and metalloproteinase-2 and metalloproteinase-2 were down-regulated.The expression of 9 down-regulates the expression of ?-integrin of the cells,thereby inducing the death of tumor cells.As the essential substances of cell growth,vitamins are often overexpressed on tumor cell surface due to requiring large amounts of vitamins during the rapidly proliferating of the tumor cells.Therefore,some vitamin receptors have become important tumor potential biomarkers.Biotin is an essential kind of water-soluble vitamin.Studies have shown that biotin receptor is overexpressed on the most human tumor cells surface,whereas low expression on the normal cells and tissues.By utilizing this characteristic of high binding of biotin and its receptor,as well as the high expression of biotin receptor in tumor tissues,biotin is coupled with an antitumor drug to prepare a biotin-targeting drug that can pass biotin on the surface of tumor cells.mediated endocytosis specific anti-cancer drugs to achieve targeted delivery of the active function,can reduce the side effects of conventional anticancer drugs to normal cells,improve the selectivity of the drug.Rhein was used as a lead compound,and biotin and rhein were linked via different linkers such as dihydric alcohols and diamines,and a series of rhein biotin conjugates had been synthesized.The results of in vitro anti-tumor activity experiments showed that the combination of rhein and biotin with certain anti-tumor activity can enhance anti-tumor activity.Preparation of biotin-targeted drugs may be achieved through the specific endocytosis of biotin receptors on the surface of tumor cells to achieve active targeted delivery of anticancer drugs,which not only reduces the toxic side effects of traditional anticancer drugs on normal cells,but also improve drug selectivity.In this paper,gambogic acid was used as a raw material,and a series of gambogic acid biotin conjugates was designed and synthesized by using the principle of merging and merging with biotin through different linking groups.The synthesized target compounds were confirmed by IR,HRMS and 1H-NMR.The antitumor activity of the target compounds was tested by thiazolyl blue colorimetric method.The experimental results showed that some of the target compounds showed significantly higher inhibitory activity against tumor cells than gambogic acid.The activity of all compounds was better than that of 5-FU,compound I f,Ig,I h,I k and I l act on He La,Hep G2,HCT-116,MCF-7 and Bel-7402 human cancer cells with IC50 values of 0.53 to 5.36 ?M and 0.63 to 3.86 ?M,respectively.0.32 to 4.17 ?M,0.27 to 0.54 ?M,and 0.25 to 0.55 ?M.The more active compound I k was selected for further study.Experiments showed that I k showed good cytotoxic activity against drug-resistant cell Bel-74 02/5-FU with IC50 value of 0.89 ?M and normal liver cell LO2(IC50 = 1.72 ?M)is less toxic and shows a certain degree of hepatic tumor cell selectivity.Ik inhibited the proliferation of Bel-7402 tumor cells,and the results showed that compound Ik may inhibit the expression of B lymphoma-2 gene(Bcl-2)and block the progression from S phase to G2/M phase.Bel-7402 cell apoptosis,to inhibit the proliferation of cells.