title: Knockdown of DEPTOR inhibits cell proliferation and increases chemosensitivity to melphalan in human multiple myeloma RPMI-8226 cells via inhibiting PI3K/AKT activity.
abstract: OBJECTIVE
  The present study determined the role of DEP domain containing mTOR-interacting protein (DEPTOR) in the proliferation, apoptosis and chemosensitivity of RPMI-8226 multiple myeloma cells, using small hairpin RNA (shRNA) to knock down DEPTOR gene expression in vitro.
  
  
  METHODS
  DEPTOR mRNA and protein levels in RPMI-8226 cells treated with DEPTOR-specific shRNA were evaluated by reverse transcription-polymerase chain reaction and Western blotting. Expression of apoptosis-associated proteins (including cleaved caspase-3 and cleaved poly-ADP ribose polymerase [PARP]) and activation of the phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homologue 1 (AKT) signalling pathway were detected by Western blotting.
  
  
  RESULTS
  Transfection of DEPTOR-specific shRNA successfully knocked down DEPTOR gene expression in transfected RPMI-8226 cells. These transfected cells, together with control RPMI-8226 cells, were treated with 20 µmol/l melphalan for 24 h. Knockdown of DEPTOR exacerbated melphalan-induced growth inhibition and apoptosis, increased levels of cleaved caspase-3 and cleaved PARP, and reduced levels of phosphor-AKT.
  
  
  CONCLUSIONS
  Downregulation of DEPTOR inhibited proliferation and increased chemosensitivity to melphalan in human multiple myeloma RPMI-8226 cells via inhibiting the PI3K/AKT pathway.
authors.affiliation: Department of Haematology and Rheumatology, The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian Province, China.
authors.forename: Hao-Ran
authors.initials: HR
authors.lastname: Zhang
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Chen
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Zeng
authors.forename: Wen-Zhong
authors.initials: WZ
authors.lastname: Que
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D055785:Gene Knockdown Techniques; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008558:Melphalan / Q000494:pharmacology*; D009101:Multiple Myeloma / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics* / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D053148:Caspase 3; D047908:Intracellular Signaling Peptides and Proteins; D008558:Melphalan; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011065:Poly(ADP-ribose) Polymerases; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D058570:TOR Serine-Threonine Kinases; C556139:DEPTOR protein, human
keywords: DEP domain containing mTOR-interacting protein (DEPTOR); Multiple myeloma; apoptosis; melphalan; phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homologue 1 (PI3K/AKT); proliferation