BACKGROUND: Most of the gastrointestinal stromal tumors (GIST) have mutations in the KIT gene, encoding a receptor tyrosine kinase. Imatinib, a receptor tyrosine kinase inhibitor, is the first-line therapy for unresectable and metastatic GISTs. Despite the revolutionary effects of imatinib, some patients are primarily resistant to imatinib and many become resistant because of acquisition of secondary mutations in KIT. This study investigated the antitumor effects of SOCS1 gene therapy, which targets several signaling pathways. METHODS: We used GIST-T1 (imatinib-sensitive) and GIST-R8 (imatinib-resistant) cells. We infected both cell lines with an adenovirus expressing SOCS1 (AdSOCS1) and examined antitumor effect and mechanisms of its agent. RESULTS: The latter harboured with secondary KIT mutation and had imatinib resistance > 1000-fold higher than the former cells. We demonstrated that AdSOCS1 significantly decreased the proliferation and induced apoptosis in both cell lines. Moreover, SOCS1 overexpression inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3), AKT, and focal adhesion kinase (FAK) in both of them. Inhibition of JAK signaling did not affect the proliferation enough. However, inhibition of the FAK signaling with an FAK inhibitor or RNA interference significantly showed inhibitory effect on cell growth and suppressed the phosphorylation of AKT, indicating a cross-talk between the AKT and FAK pathways in both the imatinib-sensitive and imatinib-resistant GIST cells. CONCLUSIONS: Our results indicate that the activation of FAK signaling is critical for proliferation of both imatinib-sensitive and -resistant GIST cells and the interference with FAK/AKT pathway might be beneficial for therapeutic target.
BACKGROUND: Most of the gastrointestinal stromal tumors (GIST) have mutations in the KIT gene, encoding a receptor tyrosine kinase. Imatinib, a receptor tyrosine kinase inhibitor, is the first-line therapy for unresectable and metastatic GISTs. Despite the revolutionary effects of imatinib, some patients are primarily resistant to imatinib and many become resistant because of acquisition of secondary mutations in KIT. This study investigated the antitumor effects of SOCS1 gene therapy, which targets several signaling pathways. METHODS: We used GIST-T1 (imatinib-sensitive) and GIST-R8 (imatinib-resistant) cells. We infected both cell lines with an adenovirus expressing SOCS1 (AdSOCS1) and examined antitumor effect and mechanisms of its agent. RESULTS: The latter harboured with secondary KIT mutation and had imatinib resistance > 1000-fold higher than the former cells. We demonstrated that AdSOCS1 significantly decreased the proliferation and induced apoptosis in both cell lines. Moreover, SOCS1 overexpression inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3), AKT, and focal adhesion kinase (FAK) in both of them. Inhibition of JAK signaling did not affect the proliferation enough. However, inhibition of the FAK signaling with an FAK inhibitor or RNA interference significantly showed inhibitory effect on cell growth and suppressed the phosphorylation of AKT, indicating a cross-talk between the AKT and FAK pathways in both the imatinib-sensitive and imatinib-resistant GIST cells. CONCLUSIONS: Our results indicate that the activation of FAK signaling is critical for proliferation of both imatinib-sensitive and -resistant GIST cells and the interference with FAK/AKT pathway might be beneficial for therapeutic target.
Authors: Maria Debiec-Rychter; Jan Cools; Herlinde Dumez; Raf Sciot; Michel Stul; Nicole Mentens; Hilde Vranckx; Bartosz Wasag; Hans Prenen; Johannes Roesel; Anne Hagemeijer; Allan Van Oosterom; Peter Marynen Journal: Gastroenterology Date: 2005-02 Impact factor: 22.682
Authors: Michael C Heinrich; Christopher L Corless; Charles D Blanke; George D Demetri; Heikki Joensuu; Peter J Roberts; Burton L Eisenberg; Margaret von Mehren; Christopher D M Fletcher; Katrin Sandau; Karen McDougall; Wen-bin Ou; Chang-Jie Chen; Jonathan A Fletcher Journal: J Clin Oncol Date: 2006-09-05 Impact factor: 44.544
Authors: Anette Duensing; Fabiola Medeiros; Bryna McConarty; Nora E Joseph; Dipak Panigrahy; Samuel Singer; Christopher D M Fletcher; George D Demetri; Jonathan A Fletcher Journal: Oncogene Date: 2004-05-13 Impact factor: 9.867
Authors: N Koon; R Schneider-Stock; M Sarlomo-Rikala; J Lasota; M Smolkin; G Petroni; A Zaika; C Boltze; F Meyer; L Andersson; S Knuutila; M Miettinen; W El-Rifai Journal: Gut Date: 2004-02 Impact factor: 23.059
Authors: Charles D Blanke; Cathryn Rankin; George D Demetri; Christopher W Ryan; Margaret von Mehren; Robert S Benjamin; A Kevin Raymond; Vivien H C Bramwell; Laurence H Baker; Robert G Maki; Michael Tanaka; J Randolph Hecht; Michael C Heinrich; Christopher D M Fletcher; John J Crowley; Ernest C Borden Journal: J Clin Oncol Date: 2008-02-01 Impact factor: 44.544