Study On Highly Selective CK2 Inhibitor With Stem Inhibition,and Its Reversal Drug Resistance

Cancer is a disease with extremely complicated pathogenesis,and has become a public health problem that seriously threaten human health.Small-molecule targeted drugs and platinum-based chemotherapeutics are the two most widely used anti-tumor drugs.However,the serious toxic side effects and drug resistance caused by them in the treatment process are the common problems that need to be solved in the development and clinical application of new drugs.Casein kinase 2（CK2）is a serine/threonine protein kinase widely found in cytoplasm and nucleus of eukaryotic cells.Unlike most other kinases,CK2 is constitutively active and more than 300 substrates are phosphorylated by CK2,making it possibly one of the most pleiotropic proteins in eukaryotic systems.It has been confirmed that CK2 is overexpressed in various solid tumors and hematomas.Therefore,CK2 is a very promising target for cancer treatment.So far,only silmitasertib（CX-4945）as a small molecule inhibitor of CK2 has entered Phase I/Ⅱ clinical trials.However,the limited specificity and anti-tumor activity of CX-4945 limit its further clinical development.Therefore,Based on the 5-（3-chloroanilinyl）benzo[c][2,6]naphthyridine ring,functional groups that can be used as a hydrogen bond donor and/or acceptor were introduced by-（CH₂）_n-.After three rounds of structure screening,compound 2-16 was found to have better CK2 inhibitory activity,CK2-specific,cytotoxicity and stronger anti-tumor activity against colon cancer than CX-4945.In addition,2-16 also exhibited a potent inhibitory effect on cancer cell stemness.Further research on the mechanismofactionrevealsthat2-16caninhibitthe Akt1（ser129）-GSK-3β（ser9）-Wnt/β-catenin signaling pathway and the expression of the stemness markers ALDH1A1,CSCs surface antigens CD44⁺,CD133⁺,and stem genes SOX2,OCT4 and Nanog,which in turn inhibits cancer cell stemness strongly.Therefore,2-16 is a highly selective CK2 inhibitor with cancer cell stemness inhibitory activity,which has a high potential for clinical developmentCancer stem cells have a pivotal impact in drug resistance,tumor metastasis,and progression of various cancer entities,including in non-small cell lung cancer（NSCLC）.In Chapter 2,we used a hydrazide group to replace the carboxyl group of CX-4945 to get compound 2-8,which has a strong inhibitory effect on CK2 and cancer cell stemness in A549cells.After that,we introduced 2-8 into the active Pt（Ⅱ）unit through the acylhydrazone bond,and designed and synthesized a novel type of Pt（Ⅱ）compound 3-2 with CK2 targeting effect.In vitro biological studies indicated that 3-2 can target CK2,and strongly reversal cancer cells resistance by reinforcing cellular accumulation of platinum,suppressing DNA damage repair and cancer cell stemness.Significantly,3-2 presented an acceptable pharmacokinetic behavior and exhibited higher tumor growth inhibitory efficacy than cisplatin either in A549 or A549/c DDP xenograft models with low toxicity.Overall,3-2 is a promising drug candidate for NSCLC treatment.Breast cancer is the most common cancer diagnosed among women in the world.Metastatic triple-negative breast cancers（TNBC）are insensitive to both hormone therapy and targeted therapy due to the lack of an effective target,which results in a very high mortality rate,and is prone to recurrence and metastasis.In view of breast cancer stem cells（BCSCs）playing a crucial role in drug resistance,tumor invasion,metastasis and tumor recurrence,we designed and synthesized several compounds by conjugating lapatinib with different cancer cell stemness inhibitors.In vitro biological studies indicated that all the resulting compounds exhibited strong cytotoxicity toward the tested breast cancer cell lines,particularly toward lapatinib resistant cells.Among them,4-9 displayed much potent cytotoxicity,especially against MDA-MB-231/lapatinib cells.Mechanism studies revealed that 4-9 enhances the inhibitory activity of the parent compound on EGFR,and can also inhibit overexpression of BCSCs surface antigens CD44⁺,CD24^-,and the BCSCs marker ALDH1A1,and BCSCs genes Nanog,OCT4,SOX2 and Kif4 during EMT and MET.Meanwhile,4-9 was able to inhibit the migration and invasion of TNBC by inhibiting the stemness of cancer cells,the expression of MMP-2 and MMP-9 proteins,and mediating the Wnt/β-catenin signaling pathway.Significantly,4-9 could inhibit the in vivo occurrence and recurrence of TNBC by inhibiting BCSCs.