Cellular irinotecan resistance in colorectal cancer and overcoming irinotecan refractoriness through various combination trials including DNA methyltransferase inhibitors: a review  

作　　者：Shogo Ozawa Toshitaka Miura Jun Terashima Wataru Habano 

机构地区：[1]Division of Pharmacodynamics and Molecular Genetics,School of Pharmacy,Iwate Medical University,Yahaba,Iwate 0283694,Japan

出　　处：《Cancer Drug Resistance》2021年第4期946-964,共19页癌症耐药（英文）

摘　　要：Treatment with pharmacological drugs for colorectal cancer(CRC)remains unsatisfactory.A major cause of failure in pharmacotherapy is the resistance of colon cancer cells to the drugs,creating an urgent issue.In this review,we summarize previous studies on the resistance of CRC cells to irinotecan and discuss possible reasons for refractoriness.Our review presents the following five major causes of irinotecan resistance in human CRC:(1)cellular irinotecan resistance is induced mainly through the increased expression of the drug efflux transporter,ABCG2;(2)cellular irinotecan resistance is also induced in association with a nuclear receptor,pregnane/steroid X receptor(PXR/SXR),which is enriched in the CYP3A4 gene enhancer region in CRC cells by exposing the cells to SN-38;(3)irinotecan-resistant cells possess either reduced DNA topoisomerase I(Top1)expression at both the mRNA and protein levels or Top1 missense mutations;(4)alterations in the tumor microenvironment lead to drug resistance through intercellular vesicle-mediated transmission of miRNAs;and(5)CRC stem cells are the most difficult targets to successfully treat CRC.In the clinical setting,CRC gradually develops resistance to initially effective irinotecan-based therapy.To solve this problem,several clinical trials,such as irinotecan plus cetuximab vs.cetuximab monotherapy,have been conducted.Another clinical trial on irinotecan plus guadecitabine,a DNA-methyltransferase inhibitor,has also been conducted.

关 键 词：Drug resistance colorectal cancer anti-cancer drugs IRINOTECAN ABCG2 DNA topoisomerase I cancer stem cells EPIGENETICS 

分 类 号：R73[医药卫生—肿瘤]