title: Autophagy inhibition plays the synergetic killing roles with radiation in the multi-drug resistant SKVCR ovarian cancer cells.
abstract: OBJECTIVE
  Autophagy has attracted attentions as a novel mechanism for tumor development. In this study Human ovarian carcinoma cell line SKOV3 and multidrug-resistant phenotype SKVCR cells were used and the roles of autophagy in radiation-induced cell death were analyzed.
  
  
  METHODS
  Cell viability was examined by colony formation and cell counting kit-8 (CCK-8) assay, 3MA and ZVAD were used to block autophagy and apoptosis, respectively. Quantitative real-time PCR was used to detect mRNA level and Western blot was used to detect protein expression, monodansylcadaverine (MDC) staining and flow cytometery were used for autophagy, apoptosis and cell cycle dynamics, respectively.
  
  
  RESULTS
  (1) The radiosensitivity exhibited differently in SKOV3 and SKVCR cells (SKOV3: D0=3.37, SKVCR: D0= 4.18); compared with SKOV3 the constitutive expression of MAPLC3 in SKVCR was higher, but no change of Caspase-3 and cleaved Caspase-3. (2) The ionizing radiation (IR)- induced apoptosis and autophagy were significant in both cells (P<0.05); inhibition of apoptosis with ZVAD showed no impact on survival of SKOV3 and SKVCR cells after radiation, while inhibition of autophagy significantly decreased viability in SKVCR cells, for SKVO3 cells only low level of radiation (2 Gy and 4 Gy) could decrease the viability(P<0.05). (3) ZVAD inhibited apoptosis and autophagy in both cells, 3MA inhibit apoptosis in SKOV3, and promote apoptosis in SKVCR, together with inhibition of autophagy. (4) G2/M arrest was induced by radiation in both cells; the accumulation of G2/M was more significant in SKOV3, 3MA attenuated the radiation-induced S phase delay in SKVCR.
  
  
  CONCLUSIONS
  IR-induced autophagy provides a self-protective mechanism against radiotherapy in SKVCR cells, the use of autophagy inhibitor, 3MA, increases the killing effects of radiation by inhibiting autophagy and radiation- induced S phase delay, also by the increase of apoptosis, which suggests a better therapeutic strategy in drug- resistant SKVCR ovarian cancer cells.
authors.affiliation: Key Laboratory of Radiobiology (Ministry of Health), School of Public Health, Jilin University, 1163 Xinmin Street, Changchun, Jilin 130021, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Liang
authors.forename: Dejuan
authors.initials: D
authors.lastname: Kong
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Nan
authors.initials: N
authors.lastname: Liang
authors.forename: Mengzi
authors.initials: M
authors.lastname: He
authors.forename: Shumei
authors.initials: S
authors.lastname: Ma
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D001343:Autophagy / Q000502:physiology*; D053148:Caspase 3 / Q000235:genetics; D059447:Cell Cycle Checkpoints / Q000528:radiation effects; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics; D009842:Oligopeptides / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D011836:Radiation Tolerance
chemical_list: C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D009842:Oligopeptides; C517629:benzyloxycarbonyl-valyl-alanyl-aspartic acid; D053148:Caspase 3