title: Macrolides sensitize EGFR-TKI-induced non-apoptotic cell death via blocking autophagy flux in pancreatic cancer cell lines.
abstract: Pancreatic cancer is one of the most difficult types of cancer to treat because of its high mortality rate due to chemotherapy resistance. We previously reported that combined treatment with gefitinib (GEF) and clarithromycin (CAM) results in enhanced cytotoxicity of GEF along with endoplasmic reticulum (ER) stress loading in non-small cell lung cancer cell lines. An epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) such as GEF induces autophagy in a pro-survival role, whereas CAM inhibits autophagy flux in various cell lines. Pronounced GEF-induced cytotoxicity therefore appears to depend on the efficacy of autophagy inhibition. In the present study, we compared the effect on autophagy inhibition among such macrolides as CAM, azithromycin (AZM), and EM900, a novel 12-membered non-antibiotic macrolide. We then assessed the enhanced GEF-induced cytotoxic effect on pancreatic cancer cell lines BxPC-3 and PANC-1. Autophagy flux analysis indicated that AZM is the most effective autophagy inhibitor of the three macrolides. CAM exhibits an inhibitory effect but less than AZM and EM900. Notably, the enhancing effect of GEF-induced cytotoxicity by combining macrolides correlated well with their efficient autophagy inhibition. However, this pronounced cytotoxicity was not due to upregulation of apoptosis induction, but was at least partially mediated through necroptosis. Our data suggest the possibility of using macrolides as 'chemosensitizers' for EGFR-TKI therapy in pancreatic cancer patients to enhance non-apoptotic tumor cell death induction.
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Mukai
authors.affiliation: Department of Biochemistry, Tokyo Medical University, Tokyo, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Moriya
authors.affiliation: Department of Biochemistry, Tokyo Medical University, Tokyo, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Hiramoto
authors.affiliation: Department of Biochemistry, Tokyo Medical University, Tokyo, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kazama
authors.affiliation: Laboratory of Electron Microscopy, Tokyo Medical University, Tokyo, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kokuba
authors.affiliation: Department of Biochemistry, Tokyo Medical University, Tokyo, Japan.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Che
authors.affiliation: Department of Clinical Oncology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sakamoto
authors.affiliation: Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sugawara
authors.affiliation: Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Sunazuka
authors.affiliation: Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ōmura
authors.affiliation: Department of Nanoparticle Translational Research, Tokyo Medical University, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Handa
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Itoi
authors.affiliation: Department of Biochemistry, Tokyo Medical University, Tokyo, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miyazawa
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D017963:Azithromycin / Q000008:administration & dosage; D045744:Cell Line, Tumor; D017291:Clarithromycin / Q000008:administration & dosage; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000235:genetics; D004917:Erythromycin / Q000008:administration & dosage / Q000031:analogs & derivatives; D000077156:Gefitinib; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D018942:Macrolides / Q000008:administration & dosage; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D011799:Quinazolines / Q000008:administration & dosage
chemical_list: C560918:(8R,9S)-8,9-dihydro-6,9-epoxy-8,9-anhydropseudoerythromycin A; D018942:Macrolides; D011799:Quinazolines; D004917:Erythromycin; D017963:Azithromycin; C512478:EGFR protein, human; D066246:ErbB Receptors; D017291:Clarithromycin; D000077156:Gefitinib