Design,synthesis And Interaction Of Phenanthroline And 4,5-diazafluorene Derivatives With Human Telomeric DNA As NSCLC Inhibitors

Based on the“combination principles”and“bioisosterism”widely used in design strategy of new drugs,forty novel compounds,composed of phenanthroline/4,5-diazafluorene as a mother structure,a pyrazol moiety,a rhodamine moiety alone,and a combination of a rhodamine and oxadiazole moieties,respectively,were designed,synthesized,bioevaluated as anti-cancer agents and their interaction mechanism explored preliminarily.At cellular level,by CCK-8 and wound healing assays toxicity and the influence on the migration and invasion to A549cells were evaluated for all compounds.By Discovery Studio 4.0LibDock,electrophoretic mobility shift assay（EMSA）and UV melting study（Tm value analysis）,a preliminary attempt is made to investigate interaction mechanism of compounds with the human telomeric DNA G-quadruplex as a target.The structures of the desired compounds were characterized by ¹H-NMR and mass spectra,and parts of them were also characterized by ¹³C-NMR.The present research is expected to find highly effective and low toxic anticancer target candidate molecules.The research of this dissertation could be divided into two sections as follows:In the first section,twenty-one 1H-imidazo[4,5-f][1,10]phenanthro-lines bearing 1,3-disubstituted pyrazol moieties were designed,synthesized and preliminarily evaluated for their antitumor activity against A549 cells in vitro.All compounds showed different degrees of antiproliferative activity against A549 cells.Especially,compounds12a–d represented the stronger activity with IC₅₀0 values in the range of1.48–2.75?M,which was more potent than that of cisplatin(IC₅₀=12.08?M).Compound 12c showed the best selectivity to A549 cells（SI=2.58）relative to human normal MRC-5 cells,which was better than that of cisplatin（SI=1.78）.Wound healing assay indicated that inhibitory effects of 12a-d on the mobility of A549 cells were significant and there existed strong concentration-dependence at the low levels of drug concentration.These novel small molecules with an extended planar aromatic system,which are similar with a G-quartet in size and shape,can facilitate the stacking interaction on the end G-quartet through?-?interactions and stabilize the G-quadruplexes.In view of such analysis,results for exploring the interaction mechanism by EMSA and UV melting study showed that theΔTm values,relative to the Tm of the G-rich DNA alone,increased greatly with the increase of drug concentration,suggesting that compounds 12a-d possessed potent stability ability for the G-quadruplexes.In the second section,nineteen novel 4,5-diazafluorene derivatives of which fifteen ones bear a 1,3-disubstituted pyrazol moiety,and four ones do a rhodanine moiety alone and a combination of rhodamine and1,3,4-oxadiazole moieties,were designed,synthesized and preliminarily evaluated for their antitumor activity against A549 cells in vitro.Likewise,all compounds showed different degrees of antiproliferative activity against A549 cells.Especially,compounds 19a-c exhibited the more potent activity with IC₅₀0 values in the range of 1.49-4.15?M,which was more potent than that of cisplatin(IC₅₀=11.90?M).Compound 19c showed the best selectivity to A549 cells（SI=4.63）,relatve to MRC-5cells,which was better than that of cisplatin（SI=1.79）.Results for 19a-c by wound healing assay are almost the same as those for 12a-c obtained in the first section.The further exploration of mechanism suggested:（1）that the 4,5-diazafluorene mother structure of compounds 19a-c could stabilize the G-quadruplexes with?-?interactions through intercalating into the interlayers of G-quartets;（2）that TheΔTm values increased greatly with the increase of drug concentration,hinting that compounds19a-c possessed potent stability ability for the G-quadruplexes.In brief,two kinds of novel 1H-imidazo[4,5-f][1,10]phenanthrolines bearing 1,3-disubstituted pyrazol moieties and 4,5-diazafluorene derivatives bearing 1,3-disubstituted pyrazol,rhodanine and1,3,4-oxadiazole moieties were designed,synthesized,examined against A549 cells activity and preliminary molecule-mediated mechanism explored.Among them,compounds（12a-d,19a-c）showed potent inhibitory activities against A549 cells and significantly inhibited the migration of A549 cells at the low compound concentration level,especially 12c and 19c.Further molecule docking study and UV-melting assay demonstrated that compound 19c possessed more potent stability behavior for the telomeric G-quadruplexes than that of 12c.Also,compound 19c showed better selectivity to A549 cells（SI=4.63）than that of 12c（SI=2.58）and cisplatin（SI=1.79）.Therefore,the compomd19c has potential to further be studied and developed as a candidate for NSCLC inhibitors.However,it is still a mystery to us that results by EMSA were always not ideal only to provide limited support for the research.This is worthy of further exploration.