title: Bevacizumab terminates homeobox B9-induced tumor proliferation by silencing microenvironmental communication.
abstract: BACKGROUND
  Homeobox B9 (HOXB9), a transcriptional factor, regulates developmental processes and tumor progression and has recently been recognized as one of important transcriptional factors related to angiogenesis. This study aimed to investigate the role of HOXB9 in tumorigenesis and angiogenesis.
  
  
  METHODS
  We examined the expression of HOXB9 in colorectal cancer using qPCR and in situ hybridization. We also examined the effect of HOXB9 overexpression in colorectal cancer using a proliferation assay, ELISA, a multiplex assay, and xenograft models. The clinical significance of HOXB9 was statistically evaluated in resected specimens.
  
  
  RESULTS
  HOXB9 was expressed in colorectal cancer specimens. HOXB9 induced angiogenesis and tumor proliferation in vitro, which resulted in high tumorigenicity in vivo and poor overall survival. Bevacizumab, an anti-vascular endothelial growth factor (VEGF) antibody, remarkably suppressed tumor proliferation by inhibiting angiogenesis in HOXB9-overexpressing xenografts, and it improved overall survival and provided prolonged progression-free survival in HOXB9-overexpressing patients. A comprehensive multiplex assay of the supernatant of cancer cells co-cultured with human vascular endothelial cells and fibroblasts indicated significantly higher interleukin-6 (IL6) levels than those in the supernatant of monocultured cells. HOXB9 overexpression in clinical specimens was significantly correlated with increased IL6 expression. An IL6-neutralizing antibody inhibited VEGF secretion and tumor proliferation in the co-culture system.
  
  
  CONCLUSIONS
  HOXB9 promotes the secretion of angiogenic factors, including VEGF, to induce tumor proliferation through microenvironmental production of cytokines including IL6 signaling. Moreover, silencing of VEGF or IL6 terminates cytokine release in tumor microenvironment. Thus, HOXB9 and IL6 may be potential biomarkers for bevacizumab treatment.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hoshino
authors.affiliation: Department of Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. tetsu@z7.keio.jp.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Hayashida
authors.forename: Akira
authors.initials: A
authors.lastname: Hirata
authors.forename: Hidena
authors.initials: H
authors.lastname: Takahashi
authors.forename: Naokazu
authors.initials: N
authors.lastname: Chiba
authors.forename: Mitsuyo
authors.initials: M
authors.lastname: Ohmura
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Wakui
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Jinno
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Shyamala
authors.initials: S
authors.lastname: Maheswaran
authors.forename: Makoto
authors.initials: M
authors.lastname: Suematsu
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kitagawa
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology*; D000068258:Bevacizumab; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000098:blood supply / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D009389:Neovascularization, Pathologic / Q000517:prevention & control; D015398:Signal Transduction; D016019:Survival Analysis; D059016:Tumor Microenvironment / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D000093242:Interleukin-6 Inhibitors
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D018398:Homeodomain Proteins; D015850:Interleukin-6; D042461:Vascular Endothelial Growth Factor A; D000093242:Interleukin-6 Inhibitors; C491257:HOXB9 protein, human; C508600:IL6 protein, human; C467484:VEGFA protein, human