Design, Synthesis And Anti-tumor Activities Of Heterocycles-fused Pyrimidine (Pyrazine) PI3K/mTOR Dual Inhibitors

PI3K-Akt-mTOR signaling pathway plays an important role in the occurrence and development of cancer cells,including participation in autophagy,inhibit apoptosis and promote cell metastasis mechanism.A wide range of inhibitors affect this signaling pathway.The PI3K/mTOR dual inhibitors had the characteristics such as high drug prices,not easy to produce drug resistance.Therefore,the development of PI3K/mTOR dual inhibitors is a potential strategy for cancer treatment.This paper discussed the relationship between the PI3K-Akt-mTOR signal pathway and the cancer.We briefly describe the research progress of PI3K/mTOR dual inhibitors in recent years.Combined with our previous studies,we designed and synthesized a series of novel heterocyclic-fused pyrimidine?pyrazine?PI3K/mTOR dual inhibitors,and discussed their preliminary analysis,in vitro anti-tumor activity and structure-activity relationships.Taking GDC-0941 as lead compound and referencing on our previous study,morpholino group was kept in the new compounds and hydrazine structure was introduced to reduce the rigidity of these compounds.The aromatic ring structures were replaced by chromone structures.As a result,we design and synthesis 11 novel thieno[3,2-d]pyrimidine compounds bearing chromone structures?CC-1^CC-11?.In order to investigate the effect of skeletal structure to anti-tumor activities,thieno[3,2-d]pyrimidine motif was changed to thieno[2,3-d]pyrimidine motif and 10 new compounds were obtained?CC-12^CC-21?.Inspired by PKI-402,heterocyclic amides structures were introduced to construct bis-aryl urea analog to get 24 new compounds?CC-22^CC-45?.According to bioisosteric principle,we took imidazopyrazinyl structure to replace thienopyrimidine structure to obtain compounds CC-46^CC-70.The structures of the new synthesized compounds were confirmed by¹H-NMR,and MS spectra and some compounds were further confirmed by ¹³C-NMR and HRMS.All the new synthesized compounds were evaluated for their cytotoxic activities against A549,PC-3,MCF-7 cell lines by MTT method,using GDC-0941 as positive control.The results showed that most of the new synthesized compounds exhibited good inhibitory activities with IC₅₀ value of 96.63⁶.39?M except T4 and T7 series compounds.The anti-tumor activities of compounds containing thieno[2,3-d]pyrimidine motif were better than those containing thieno[3,2-d]pyrimidine motif.Especially,compound CC-20 showed anti-tumor activity against A549,PC-3 and MCF-7 cell lines with IC₅₀ values of 13.56,22.59,45.88?M,which was 1.5 to 2.5fold more active than compound CC-7,respectively.Comparing the three kinds of thieno pyrimidines which bearing different heterocyclic amide structures,we found that compounds bearing pyridine amides showed better anti-tumor activity than that of other compounds.Compound CC-34 showed moderate anti-tumor activity against A549,PC-3 and MCF-7 cell lines with IC₅₀ values of 6.58,15.56,17.16?M.In addition,the anti-tumor activities were improved by replacing the thienopyrimidine unit with imidazopyrazin unit.And compounds which contain pyridine amides showed better anti-tumor activity than other compounds.Compound CC-64 showed anti-tumor activity against A549,PC-3and MCF-7 cell lines with IC₅₀ values of 6.39,12.65,10.23?M.Compounds CC-1^CC-21 were evaluated for mTOR and PI3K?kinases activity by LANCE^?Ultra or Kinase-Glo?Luminescent kinase assay,using PI3K?/mTOR inhibitors PI-103 positive control.The pharmacological results showed that most of the prepared compounds exhibited moderate antitumor activity.Compounds CC-20,CC-21 at 10?M concentration have a high inhibition rate against PI3K?,mTOR.?91.2%,81.0%;90.6%,97.2%?.They showed anti-tumor activity against PI3K?,mTORwith IC₅₀ values of 1.53?0.92?M and 2.35?0.16?M?According to the results,compounds with thieno[2,3-d]pyrimidine skeleton structure showed better anti-tumor activity than those with thieno[3,2-d]pyrimidine skeletal structure.In addition,different substituents on chromone had significant impact on the activity of the compounds.In general,compounds with electron withdrawing substituents showed batter anti-tumor activity than those with electron donating substituents.Especially,compounds which were substituted with 6-NO₂ or6-COOH showed the best antitumor activity.Comparing heterocyclic amides,T4 and T7 series compounds had little activity.This result may be caused by the high rigidity of these compounds.Substituents have an important impact on the activity of the compounds.For example,large substituent lead to low activity in the series compounds of T5.The series compounds of T6 showed that electron donating substituents were better than electron withdrawing substituents to anti-tumor activity.In a summary,this topic designed,synthesized and screened a series of novel heterocyclic-fused pyrimidine?pyrazine?PI3K/mTOR dual inhibitors.Further study and discussion about the structure-activity relationship of these compounds lead future research foundation.