title: A potent therapeutics for gallbladder cancer by combinatorial inhibition of the MAPK and mTOR signaling networks.
abstract: BACKGROUND
  Gallbladder cancer (GBC) is the most common type of cancer with the worst prognosis among the bile duct cancers. There still remains a clear need for effective mechanism-based novel therapeutic approaches. A crosstalk between mitogen-activated protein kinase (MAPK) and the mammalian target of Rapamycin (mTOR) signaling pathways has been reported in several cancers. We hypothesized that targeting both pathways in combination will be a potent therapeutic for GBC.
  
  
  METHODS
  Expression of phospho-ERK and phospho-S6rp protein were evaluated by immunostaining in surgically resected GBC specimens (n = 30). GBC cell lines and a xenograft model were treated with CI-1040, an inhibitor of MEK (mitogen-activated protein kinase kinase) and RAD001, an inhibitor of mTOR, alone or in combination, and then, we examined the cell proliferation and tumor growth, cell cycle status, and apoptosis.
  
  
  RESULTS
  Analysis of human GBC tissues demonstrated that MAPK and mTOR signaling pathways were frequently coordinately dysregulated in one third of them. The combination therapy inhibited both signaling pathways and subsequently inhibited human GBC cell proliferation in vitro and xenograft tumor growth in vivo. Compared to the single treatment, the combination therapy significantly induced cell cycle arrest and apoptosis with decreased cyclin D1 expression.
  
  
  CONCLUSIONS
  The double blockade of MAPK and mTOR signaling pathways inhibits the signal crosstalk and shows anti-tumor activity, which can be a potent therapeutic for GBC, especially for the patients with hyperactivated signaling of both pathways.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Dai
authors.initials: D
authors.lastname: Mohri
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan. hideijichi-gi@umin.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ijichi
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Miyabayashi
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Takahashi
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Yotaro
authors.initials: Y
authors.lastname: Kudo
authors.affiliation: Division of Gastroenterology, Cancer Institute Hospital, 3-8-31 Ariake, Koutou-Ku, Tokyo, 135-8550, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Asaoka
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Division of Clinical Genome Research, Institute of Medical Sciences, University of Tokyo, 4-6-1 Shiroganedai, Minato-Ku, Tokyo, 108-8639, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Ikenoue
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tateishi
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tada
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isayama
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides / Q000627:therapeutic use*; D002277:Carcinoma / Q000188:drug therapy* / Q000473:pathology; D018929:Cell Culture Techniques; D000068338:Everolimus / Q000627:therapeutic use*; D005260:Female; D005706:Gallbladder Neoplasms / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D023041:Xenograft Model Antitumor Assays
chemical_list: C120227:2-(2-chloro-4-iodophenylamino)-N-cyclopropylmethoxy-3,4-difluorobenzamide; D000970:Antineoplastic Agents; D001549:Benzamides; D000068338:Everolimus; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases
keywords: Crosstalk; GBC; MAPK; mTOR