Inhibition of Src family kinases overcomes anoikis resistance induced by spheroid formation and facilitates cisplatin-induced apoptosis in human mesothelioma cells.
Malignant mesothelioma is an aggressive tumor arising from mesothelial cells of serous membranes, and forms spheroid-like cell aggregates in pleural and peritoneal effusions. We examined the levels of anoikis, apoptosis induced by the detachment of cells from the extracellur matrix, in suspension culture in the human mesothelioma cell line NCI-H2052. NCI-H2052 cells were adherent in conventional monolayer cultures, but were found to form spheroids in suspension cultures using dishes with ultra-low cell binding capacity. NCI-H2052 cells proliferated in both cultures, but the proliferation rate was markedly lower in suspension cultures than in monolayer cultures. In addition, NCI-H2052 cells in suspension cultures showed little apoptosis, suggesting that the suspension culture induces anoikis resistance. Western blot analysis revealed that suspension cultures induced activation of Src family kinases (SFK) after spheroid formation. Dasatinib, an inhibitor of multi-tyrosine kinases including SFK, abolished anoikis resistance in suspension cultures, indicating that SFK activated by spheroid formation are responsible for anoikis resistance. Cisplatin induced apoptosis in NCI-H2052 cells, but the apoptotic rate was significantly lower in suspension cultures than in monolayer cultures, suggesting that spheroid formation is involved in cisplatin resistance. Furthermore, a combination of dasatinib and cisplatin induced apoptosis more significantly than either alone in suspension cultures. These results suggest that spheroid formation induces resistance to anoikis and to cisplatin through SFK activation and that dasatinib facilitates cisplatin-induced apoptosis in human mesothelioma cells.
Department of Environmental and Preventive Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Ryoji
R
Eguchi
Department of Thoracic Oncology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Yumiko
Y
Fujita
Department of Thoracic Oncology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Chiharu
C
Tabata
Division of Hematology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Hiroyasu
H
Ogawa
Department of Environmental and Preventive Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Ichiro
I
Wakabayashi
Department of Thoracic Oncology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Takashi
T
Nakano
Department of Transfusion Medicine and Cellular Therapy, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
Yoshihiro
Y
Fujimori
D023102:Anoikis; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D000069439:Dasatinib / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D006801:Humans; D008654:Mesothelioma / Q000188:drug therapy / Q000201:enzymology*; D018874:Spheroids, Cellular / Q000187:drug effects / Q000201:enzymology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
D000970:Antineoplastic Agents; D019061:src-Family Kinases; D002945:Cisplatin; D000069439:Dasatinib