Design,synthesis And Activity Study Of A Series Of Melatonin Derivatives As Anti-inflammation And Anti-cancer Agents

Chronic inflammation is highly correlated with the occurrence and development of most common diseases and interacts with these diseases.For example,continuous inflammation in the brain can cause damage or necrosis of nerve cells,leading to neurological dysfunction and thus to neurodegenerative diseases.For another example,chronic inflammation can also induce DNA damage and transcription of proto-oncogenes and the activation of oncogenic signaling pathways in tumor cells,leading to the tumorigenesis and malignant progression.Therefore,the development of drugs that treat chronic inflammation or target tumor inflammatory microenvironment has important clinical application value.To this end,to combat the neuroinflammation,glioma,and tumors that are highly related to inflammation,a series melatonin derivatives as multifunctional COX-2 inhibitors and COX-2/STAT3 dual inhibitors were designed and synthesized according to the combination principle and conducted in vivo and in vitro biological activity evaluation.The main contents are as follows:The first part:23 of N-salicyloyl tryptamine derivatives as multifunctional COX-2 inhibitors were designed and their new application for anti-neuroinflammation was disclosed.In cyclooxygenase assay,15 compounds displayed extremely preferable COX-2 inhibition than N-salicyloyl tryptamine and have only weak selectivity for COX-2.Among them,a compound 16 with the best COX-2 inhibition was screened out.In LPS-induced C6 and BV2 cell models,compounds 3,13,16 decreased the production of proinflammatory mediators NO,PGE₂,TNF-?,i NOS,COX-2 and ROS,while increased the production of IL-10.Besides,compounds 3,13 and 16 attenuated the activation of BV2 and C6 cells.More importantly,compounds 3 and 16 reduced GFAP and Iba-1 levels in the hippocampus in vivo,and displayed neuroprotection in Nissl staining.In addition,both compounds 3 and 16 had high safety(LD₅₀>1000mg/kg,i.p).Longer plasma half-life of compounds 3 and 16 than melatonin pharmacokinetic study on rats.The second part,based on the above results,we modified the N-anthraniloyl tryptamine derivatives that exerts the activity of anti-gliomas,and designed,synthesized and identified 34 N-anthraniloyl tryptamine compounds that simultaneously inhibit COX-2 and block the STAT3 signaling pathway.Among them,a compound NP16 with the best anti-proliferative activity and favorable COX-2inhibition was screened out through the COX-2 enzyme inhibitory activity and the proliferation inhibition test of U251,U87MG,C6 cells.Delightedly,NP16 decreased the level of p-JAK2 and nuclear translocation of STAT3,suppressed the expression of COX-2 in GBM cell lines,downregulated C6 cell induced-the MMP-9 expression of BV2.In addition,it attenuated colony formation and Ed U-positive cell ratio of U87MG and U251,induced obvious G2/M arrest,ROS generation and apoptosis,influenced apoptosis-related protein expression,and reduced the migration and invasion capacity of glioma cells in vitro.Moreover,NP16 displayed favorable pharmacokinetic profiles including long half-life(11.43±0.43 h)and high blood-brain barrier permeability.Besides,NP16 markedly reduced the volume and weight of tumor,improved survival rate,increased the expression of E-cadherin and reduced overproduction of PGE₂,VEGF-A,MMP-9,GFAP and the level of p-STAT3 in tumor lysates,and decreased the density of new blood vessels,as well as improved the anxiety-like behavior in C6glioma model.The third part:in order to explore the anti-tumor spectrum of the above-mentioned N-anthraniloyl tryptamine derivatives by anti-tumor activity screening on thirteen different types of tumor cells.It was found that most of the compounds have strong inhibitory activity on two typical inflammatory-related cancers.The compound 1 exerts a broad-spectrum anti-cancer activity.Besides,we selected COX-2 deficient cells to explore the mechanism of compound 1 inhibiting the STAT3 pathway.It was proved that compound 1 significantly down-regulates STAT3 phosphorylation and nuclear translocation,and inhibits the downstream protein Bcl-2 of STAT3.Docking studies have verified that compound 1 can bind to the SH2 domain of STAT3,and these results confirm that these compounds can inhibit the STAT3 pathway.Inaddtionally,compound1 can significantly inhibit the proliferation ability of cancer cells and induce the G0/G1phase arrest,significantly change cell morphology,induce apoptosis and ROS generation and reduce the migration and invasion capacity of cancer cell in vitro.In short,based on the combination principle,a series of compounds with anti-cancer and anti-inflammatory activities were designed and synthesized,which have the effect of targeting COX-2 and STAT3,and can penetrate the BBB to combat inflammation and cancer of the CNS,and can also significantly inhibit malignant tumors of the digestive system that are closely related to inflammation.