Synthesis And Anti-Tumor Evaluation Of 6H-Indolo[2,3-b] Quinoxaline Derivatives

6H-indolo[2,3-b]quinoxaline derivatives exhibit promising antiviral and anti-tumor activity.Its antiviral and mechanism have been investigated by many groups,yet there are few reports focus on the mechanism of its antitumor acitivity.In this dissertation,series of 38 6H-indolo[2,3-b]quinoxaline derivatives were synthesized and their antitumor,as well as action mechanism were investigated.The disertation is composed of four chapters:In chapter one,the progress on the synthesis and biological evaluation of indoloquinoxaline compounds is briefly summarized.In chapter two,The synthesis of 6H-indolo[2,3-b]quinoxaline derivatives were reported.O-phenylenediamine and isatin derivatives,which were used as the starting materials,After sequential Friedlander condensation,alkylation of dihaloalkanes and amination substitution reaction,38 6H-indolo[2,3-b]quinoxaline derivatives were synthesized.All target compounds were characterized and comfirmed by NMR and HRMS.In chapter three,MTT assay was used to evaluate the antiproliferation of the target compounds against the human bladder cancer cells（T24）,gastric cancer cells（MGC-803）,cervical cancer cells He La,lung cancer cells（NCI-H460）,liver cancer cells（SMMC-7721）and normal liver cells（HL-7702）.The result indicated that most of the target compounds exhibit promising antiproliferation.Among thees compounds 7cc and 8bc demonstrate the most pontency against the T24 cell lines,with a IC₅₀ valule of 2.4±0.27,3.4±0.37μM,respectively.In addition,the antiproliferation against some hepatoma cell lines with different p53 status such as He P3B2.1-7 cell lines（null-p53）,Hu H-7（m-p53）,PLC/PRF/5（m-p53）of the compounds that with good activity to SMMC-7721 cell lines（w-p53）were also evaluated.The results indicated that 7cc,8bc also exhibited good inhibition against the tested cell lines,suggesting that their anti-proliferation against liver cancer cell is p53 independent.In chapter four,the interaction betweem the representative 7cc,8bc with the double stranded（ct-DNA or G4-DNA）was studied via UV-visible,fluorescence,and circular spectroscopy.The results indicated that 7cc,8bc can intercalate into ct-DNA,resulting in fluorescence quenching when adding to the EB–ct-DNA system.The binding constant of the 7cc,8bc with ct-DNA is 6.7×10⁷ M^-1 and1.5×10⁷ M^-1,respectively.And the fluorescence quenching rate constants of the EB–ct-DNA is 0.90×10⁴ L/mol and 0.60×10⁴ L/mol.In additon,the 7cc,8bc can strongly bind to the G4-DNA such as c-myc Cx,HTG21 and c-myc Ts,leading to change in its physiological activity.Then,studied on the antitumor activity of 7cc,8bc,further.Flow cytometry was used to investigate the cell cycle arrest,apoptosis,the change in the intracellular active oxygen level,calcium ion concentration,mitochondria membrane potential and the activation of Caspase-3/8 and Caspase-9in T24 cells when treated by 7cc,8bc.The results showed that 7cc arrest cell cycle at G2 phase in 5,10μM but at S phase while in 15μM.8bc arrest cell cycle at G2phase,active oxygen level and calcium ion concentration are increased,while decreasing the mitochondrial membrane potential,activating the Caspase-9 and Caspase-3/8 and inducing apoptosis.Hoechst 33258/DID staining assay was also used to further evaluate the apoptotic induction after treatment with 7cc,8bc.The results indicated that both 7cc and 8bc can significantly induce apoptosis in T24cells.At the same time,the apoptosis in MGC-803,SMMC-7721,He P3B2.1-7 and PLC/PRF/5 cells when treated with 7cc was further explored.The results showned that with the increase of 7cc concentration,the apoptosis in the test cell lines that with different p53 status obvious increasing,suggesting that 7cc can also induce apoptosis in hepatoma cell lines in a p53-independent manner.