405 VAV3, A POSSIBLE KEY MOLECULE, ENHANCES ANDROGEN-INDEPENDENT GROWTH AND THE MALIGNANT POTENTIAL OF PROSTATE CANCER CELLS UNDER CHRONIC HYPOXIA

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research1 Apr 2011405 VAV3, A POSSIBLE KEY MOLECULE, ENHANCES ANDROGEN-INDEPENDENT GROWTH AND THE MALIGNANT POTENTIAL OF PROSTATE CANCER CELLS UNDER CHRONIC HYPOXIA Kenichi Hirai, Takeo Nomura, Mutsushi Yamasaki, Takanori Matsubara, Fuminori Sato, Masatsugu Moriyama, and Hiromitsu Mimata Kenichi HiraiKenichi Hirai Oita, Japan More articles by this author , Takeo NomuraTakeo Nomura Oita, Japan More articles by this author , Mutsushi YamasakiMutsushi Yamasaki Oita, Japan More articles by this author , Takanori MatsubaraTakanori Matsubara Oita, Japan More articles by this author , Fuminori SatoFuminori Sato Oita, Japan More articles by this author , Masatsugu MoriyamaMasatsugu Moriyama Oita, Japan More articles by this author , and Hiromitsu MimataHiromitsu Mimata Oita, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.494AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Hypoxia occurs in many solid tumors, including prostate cancer, and enhances tumor progression and treatment resistance. Our previous studies showed that chronic hypoxia promoted androgen-independent growth and malignant cell behavior in a human prostate cancer cell line. From the results of multi-pathway analysis of gene expression of LNCaP cells under a chronic hypoxic condition, we specifically focused on the biological functions of Vav3 gene in vitro. METHODS We analyzed the gene expression profiles of LNCaP cells under normoxic, acute hypoxic (1% oxygen for forty-eight hours), and chronic hypoxic conditions (cultured over six months). Comprehensive mRNA profiling was performed using an Agilent 44K array platform, and we investigated the association between elevated genes and tumor behavior by the applications of Ingenuity Pathways Analysis. From the results, we identified the Vav3 gene and closely analyzed the details of the gene in vitro. We validated the expression by quantitative RT-PCR and Western blot analyses. To analyze the function of Vav3, knockdown by siRNA was performed. Next, we transfected LNCaP with the Vav3 cDNA expression vector (control cells were transfected with neo expression vector) and isolated stable clones with high or low expression. The growth of cancer cells was evaluated in vitro. Also, we examined cell invasiveness and migration using the Matrigel invasion assay. For cell cycle analysis, flow cytometric analysis of propidium iodide-stained nuclei was carried out. RESULTS The results were as follows: (1) Vav3 mRNA and protein expression levels were increased in LNCaP cells under chronic hypoxia, respectively; (2) chronic hypoxia increased both the invasiveness and migration of LNCaP cells; (3) LNCaP cells under chronic hypoxia showed less invasiveness and cell motility as well as suppressed their growth rates by interrupting Vav3 expression using Vav3 siRNA; (4) Vav3 expression positively correlated with the growth, invasiveness, and motility of LNCaP cells; and (5) interrupting the Vav3 signaling axis with siRNA led to the apoptosis of LNCaP cells via the mitochondrial pathway, with increased activation of caspases-3, and -9 and cleaved PARP. CONCLUSIONS Our results showed that chronic hypoxia promoted the malignant potential of prostate cancer cells via the overexpression of Vav3. Therefore, targeting the Vav3 signaling pathway could prove to be a promising approach for the treatment of progressive or castration resistant prostate cancer. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e163-e164 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kenichi Hirai Oita, Japan More articles by this author Takeo Nomura Oita, Japan More articles by this author Mutsushi Yamasaki Oita, Japan More articles by this author Takanori Matsubara Oita, Japan More articles by this author Fuminori Sato Oita, Japan More articles by this author Masatsugu Moriyama Oita, Japan More articles by this author Hiromitsu Mimata Oita, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...