Design,Synthesis And Antitumor Activity Evaluation Of Novel[1,2,4]Triazolo[1,5-A]Pyrimidines

In recent years,the incidence of malignant tumors has shown an upward trend,which has become a major category of diseases that seriously endangers human life,health and restricts social and economic development.However,the existing anti-cancer drugs generally have shortcomings such as poor selectivity,high toxicity and drug resistance.Therefore,the development of new anti-cancer drugs is of great significance.It has been reported that[1,2,4]triazolo[1,5-a]pyrimidine compounds have a wide range of pharmacological activities,such as antiviral,antibacterial,antiparasitic,anti-inflammatory,antitumor activities,etc.,and play an important role in drug research,especially in anti-tumor field.In addition,as a JAK inhibitor,tofacitinib was approved by the FDA for the treatment of myeloproliferative disorders,which has been found to induce G1 cell-cycle arrest and inhibit tumor growth in Epstein-Barr virus-associated T and natural killer cell lymphoma cells.In order to obtain novel and effective anti-tumor drugs,we designed and synthesized a series of novel[1,2,4]triazolo[1,5-a]pyrimidine derivatives by performing scaffold hybridization strategy by replacing the 3-oxopropanenitrile moiety in tofacitinib with the privileged[1,2,4]triazolo[1,5-a]pyrimidine scaffold,followed by evaluating their anti-cancer activity.In this series of compounds,we found compound C18 showed strong antitumor activity against MGC-803 gastric cancer cells(IC₅₀=2.68μM),which was selected to carry out a series of underlying biological mechanism.The clone formation experiment showed that compound C18 could effectively inhibit the clone formation of MGC-803cells.Besides,compound C18 could significantly inhibit the migration of MGC-803cells.Hoechst staining and AnnexinⅤ-FITC/PI double staining indicated that compound C18 could induce apoptosis of MGC-803 cells in a concentration and time-dependent manner.However,compound C18 showed almost no effect on cell cycle distribution.The JC-1 staining method was used to detect the mitochondrial membrane potential,which indicated that compound C18 could decrease the mitochondrial membrane potential,leading to mitochondrial damage.Western Blot experiment showed that compound C18 could downregulate the expression of anti-apoptotic proteins Bcl-2 and Mcl-1,increase the expression of pro-apoptotic protein Bax in a concentration-dependent manner,and further activate the release of cytochrome c from mitochondria to the cytoplasm,thereby activating the Caspase cascade and further inducing cell apoptosis.In addition,compound C18 could also induce mitochondrial dysfunction and apoptosis of MGC-803 cells through activating p38 and JNK signaling pathways.In vivo antitumor studies showed that compound C18 could significantly inhibit the growth of gastric cancer tumors without obvious toxicity.These results indicate that the[1,2,4]triazolo[1,5-a]pyrimidine skeleton can be used as a privileged scaffold for the development of new antitumor drugs.