Study On The Structure-activity Relationship Of 3,3’-Diindolylmethane Derivatives Based On Estrogen Receptor And Peroxisome Proliferator-activated Receptor

In recent years,indole-3-methanol(I3C)has been identified as a promising therapeutic agent for breast cancer by regulating estrogen metabolism.Studies have shown that 3,3’-Diindolylmethane(DIM)produced by the conversion of indole-3-methanol in body is the main effective substance that exerts biological effects.Derivatives of 3,3’-Diindolylmethane have been found to exert biological effects by targeting Estrogen Receptor(ER)and Peroxisome Proliferator-Activated Receptor(PPAR),of which,however,the structure-activity relationship(SAR)is still unclear.In this study,a series of DIM derivatives were synthesized and their SAR based on the regulation of ER and PPAR activities were investigated.Firstly,we tested the regulation of ER and PPAR transcriptional activity by DIM derivatives using dual luciferase reporter assays.Our results showed that DIM itself induced ERa transcriptional activity,and the substitutions of different aromatic groups at the R1 position of alkyl group were of different effects in regard to activating ERa.The phenyl substitution slightly enhanced the activation of ERa.If the phenyl group continued to be substituted with groups such as-F,-Cl,-OH,-CH3,the substituted derivatives maintained the activity of activating ERa.However,an electron withdrawing group(such as-F)substitution was much superior to an electron donating group(such as-OH)substitution,and the 3-position substitution on the benzene ring was much better than the 2-and 4-position substitutions.We found that DIM itself had no ability of activating PPARy,and the aromatic ring substitution at the R1 position of the alkyl group did not significantly increase the ability of activating PPARyalso.However,the 5-CH3 modification of R3/R4 indole ring-could greatly increase the ability of activating PPARy.Our MTT proliferation experiments found that derivatives showed different effects on the proliferation of breast cancer cells.Further studies have found that derivatives only activating ERa promoted ERa-positive rather than ERa-negative breast cancer cell proliferation significantly,revealing the ERa-dependent effect;the derivatives only activating PPARγ significantly inhibited the proliferation of both ERα-positive and negative breast cancer cells,and was of certain PPARγ-dependent manner;certain compounds with ERα and PPARγ dual activation effects may have a compromised effect on breast cancer cell proliferation.We investigated the binding activity of some representative derivatives in vitro.It was found that the ability of the derivatives to bind to ERα and PPARγ was positively correlated with their activation of ERα and PPARγ,suggesting that these derivatives of DIM were ligands of ERαand/or PPARγ and exerted their biological activities by directly targeting ERα and/or PPARy.In summary,this study reveals the structure-activity relationship of DIM derivatives based on regulating ERα and PPARγ transcriptional activities.At the same time,the study also reveals that DIM derivatives may exert their anti-breast cancer effects by targeting PPARy,laying the foundation for the optimization and application of DIM derivatives in the treatment of breast cancer,especially triple negative breast cancer.