Fibronectin protects lung cancer cells against docetaxel-induced apoptosis by promoting Src and caspase-8 phosphorylation

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• 作者：Sida Qin ; Boxiang Zhang ; Guodong Xiao ; Xin Sun ; Gang Li ; Guanghong Huang…
• 关键词：Lung cancer ; Fibronectin ; Docetaxel ; Apoptosis
• 刊名：Tumor Biology
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：37
• 期：10
• 页码：13509-13520
• 全文大小：1,410 KB
• 刊物主题：Cancer Research;
• 出版者：Springer Netherlands
• ISSN：1423-0380
• 卷排序：37

文摘

Fibronectin is involved in orchestrating many diverse cellular behaviors, including adhesion, invasion, differentiation, and proliferation and recently has also been shown to participate in the development of chemoresistance. In this study, we found that fibronectin expression was inversely correlated with clinical responses to docetaxel treatment in non-small cell lung cancer patients. Subsequently, we showed that fibronectin pretreatment could enhance cell viability and reduce apoptosis in docetaxel-treated lung cancer cells because fibronectin induced phosphorylated Src and caspase-8, rendering the later inactive, thus inhibiting docetaxel-induced apoptosis. The inhibition of apoptosis by fibronectin was found to be enhanced by Src overexpression and reversed by Src knockdown in lung cancer cells. Further investigation revealed that a downregulation of phospho-Src via treatment with a Src kinase inhibitor could also abolish fibronectin activity and recover docetaxel-induced apoptosis. Molecular studies revealed that this reversion was due to decreased phospho-Src levels rather than a reduction in total Src expression. Inhibition of phospho-Src reduced phospho-caspase-8 and promoted caspase-8 activity, restoring apoptosis following docetaxel and fibronectin co-treatment. Finally, xenografts experiments demonstrated that fibronectin promoted lung cancer cell proliferation during docetaxel treatment in vivo. Our findings indicate that fibronectin promotes Src and caspase-8 phosphorylation in lung cancer cells, which decreases caspase-8 activation and protects tumor cells from docetaxel-induced apoptosis. Therefore, the fibronectin/Src/caspase-8 pathway may play a crucial role in docetaxel resistance in lung cancer.