title: A mechanistic study on reduced toxicity of irinotecan by coadministered thalidomide, a tumor necrosis factor-alpha inhibitor.
abstract: Dose-limiting diarrhea and myelosuppression compromise the success of irinotecan (7-ethyl-10-[4-[1-piperidino]-1-piperidino]carbonyloxycamptothecin) (CPT-11)-based chemotherapy. A recent pilot study indicates that thalidomide attenuates the toxicity of CPT-11 in cancer patients. This study aimed to investigate whether coadministered thalidomide modulated the toxicities of CPT-11 and the underlying mechanisms using several in vivo and in vitro models. Diarrhea, intestinal lesions, cytokine expression, and intestinal epithelial apoptosis were monitored. Coadministered thalidomide (100 mg/kg i.p. for 8 days) significantly attenuated body weight loss, myelosuppression, diarrhea, and intestinal histological lesions caused by CPT-11 (60 mg/kg i.v. for 4 days). This was accompanied by inhibition of tumor necrosis factor-alpha, interleukins 1 and 6 and interferon-gamma, and intestinal epithelial apoptosis. Coadministered thalidomide also significantly increased the systemic exposure of CPT-11 but decreased that of SN-38 (7-ethyl-10-hydroxycampothecin). It significantly reduced the biliary excretion and cecal exposure of CPT-11, SN-38, and SN-38 glucuronide. Thalidomide hydrolytic products inhibited hydrolysis of CPT-11 in rat liver microsomes but not in primary rat hepatocytes. In addition, thalidomide and its major hydrolytic products, such as phthaloyl glutamic acid (PGA), increased the intracellular accumulation of CPT-11 and SN-38 in primary rat hepatocytes. They also significantly decreased the transport of CPT-11 and SN-38 in Caco-2 and parental MDCKII cells. Thalidomide and PGA also significantly inhibited P-glycoprotein (PgP/MDR1), multidrug resistance-associated protein (MRP1)- and MRP2-mediated CPT-11 and SN-38 transport in MDCKII cells. These results provide insights into the pharmacodynamic and pharmacokinetic mechanisms for the protective effects of thalidomide against CPT-11-induced intestinal toxicity.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Science Drive 4, Singapore 117543.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Yang
authors.forename: Ze-Ping
authors.initials: ZP
authors.lastname: Hu
authors.forename: An-Long
authors.initials: AL
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Duan
authors.forename: Yi-Zhun
authors.initials: YZ
authors.lastname: Zhu
authors.forename: Min
authors.initials: M
authors.lastname: Huang
authors.forename: Fwu-Shan
authors.initials: FS
authors.lastname: Sheu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Bian
authors.forename: Eli
authors.initials: E
authors.lastname: Chan
authors.forename: Xiaotian
authors.initials: X
authors.lastname: Li
authors.forename: Jian-Cheng
authors.initials: JC
authors.lastname: Wang
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Zhou
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000502:physiology; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D001646:Bile / Q000378:metabolism; D001798:Blood Proteins / Q000378:metabolism; D001853:Bone Marrow / Q000187:drug effects; D018938:Caco-2 Cells; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics / Q000633:toxicity; D003967:Diarrhea / Q000517:prevention & control; D022781:Hepatocytes / Q000187:drug effects; D006801:Humans; D007422:Intestines / Q000187:drug effects / Q000473:pathology; D000077146:Irinotecan; D008297:Male; D026901:Membrane Transport Proteins / Q000502:physiology; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013792:Thalidomide / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D015431:Weight Loss / Q000187:drug effects
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D001798:Blood Proteins; D002166:Camptothecin; D000077146:Irinotecan; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; D013792:Thalidomide; D014409:Tumor Necrosis Factor-alpha; C000715087:ABCC2 protein, human