title: HPIP promotes epithelial-mesenchymal transition and cisplatin resistance in ovarian cancer cells through PI3K/AKT pathway activation.
abstract: OBJECTIVE
  Hematopoietic PBX interacting protein (HPIP), a scaffold protein, is known to regulate the proliferation, migration and invasion in different cancer cell types. The aim of this study was to assess the role of HPIP in ovarian cancer cell migration, invasion and epithelial-mesenchymal transition (EMT), and to unravel the mechanism by which it regulates these processes.
  
  
  METHODS
  HPIP expression was assessed by immunohistochemistry of tissue microarrays containing primary ovarian tumor samples of different grades. OAW42, an ovarian carcinoma-derived cell line exhibiting a high HPIP expression, was used to study the role of HPIP in cell migration, invasion and EMT. HPIP knockdown in these cells was achieved using a small hairpin RNA (shRNA) approach. Cell migration and invasion were assessed using scratch wound and transwell invasion assays, respectively. The extent of EMT was assessed by determining the expression levels of Snail, Vimentin and E-cadherin using Western blotting. The effect of HPIP expression on AKT and MAPK activation was also investigated by Western blotting. Cell viabilities in response to cisplatin treatment were assessed using a MTT assay, whereas apoptosis was assessed by determining caspase-3 and PARP cleavage in ovarian carcinoma-derived SKOV3 cells.
  
  
  RESULTS
  We found that HPIP is highly expressed in high-grade primary ovarian tumors. In addition, we found that HPIP promotes the migration, invasion and EMT in OAW42 cells and induces EMT in these cells via activation of the PI3K/AKT pathway. The latter was found to lead to stabilization of the Snail protein and to repression of E-cadherin expression through inactivation of GSK-3β. We also found that HPIP expression confers cisplatin resistance to SKOV3 cells after prolonged exposure and that its subsequent knockdown decreases the viability of these cells and increases caspase-3 activation and PARP proteolysis in these cells following cisplatin treatment.
  
  
  CONCLUSIONS
  From these results we conclude that HPIP expression is associated with high-grade ovarian tumors and may promote their migration, invasion and EMT, a process that is associated with metastasis. In addition, we conclude that HPIP may serve as a potential therapeutic target for cisplatin resistant ovarian tumors.
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India.
authors.forename: Suresh
authors.initials: S
authors.lastname: Bugide
authors.affiliation: Department of Obstetrics and Gynecology, UT Health Science Center, San Antonio, USA.
authors.forename: Vijay Kumar
authors.initials: VK
authors.lastname: Gonugunta
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India.
authors.forename: Vasudevarao
authors.initials: V
authors.lastname: Penugurti
authors.affiliation: Department of Biotechnology, Acharya Nagarjuna University, Guntur, AP, India.
authors.forename: Vijaya Lakshmi
authors.initials: VL
authors.lastname: Malisetty
authors.affiliation: Department of Obstetrics and Gynecology, UT Health Science Center, San Antonio, USA.
authors.forename: Ratna K
authors.initials: RK
authors.lastname: Vadlamudi
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India. manavbrahma@gmail.com.
authors.forename: Bramanandam
authors.initials: B
authors.lastname: Manavathi
mesh_terms: D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005260:Female; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D010051:Ovarian Neoplasms / Q000201:enzymology / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D055550:Protein Stability / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D000071250:Snail Family Transcription Factors / Q000378:metabolism
chemical_list: C469750:HCFC1R1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D000071250:Snail Family Transcription Factors; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D002945:Cisplatin
keywords: Cell migration; Epithelial-mesenchymal transition (EMT); HPIP/PBXIP1; Ovarian cancer; PI3K/AKT pathway