C-terminal tensin-like protein mediates invasion of human lung cancer cells and is regulated by signal transducer and activator of transcription 3

Abstract

C-terminal tensin-like (Cten) protein, a component of focal adhesions, contributes to cell motility and invasion in multiple human cancers. Epidermal growth factor can activate signal transducer and activator of transcription 3, and both contribute to invasion through focal adhesion interactions. We hypothesize that Cten may mediate invasion of lung cancer cells provided by epidermal growth factor via signal transducer and activator of transcription 3. Four human non-small cell lung cancer cell lines were treated with epidermal growth factor to evaluate activation of the signal transducer and activator of transcription 3 pathway and induction of Cten expression. Chemical inhibition of signal transducer and activator of transcription 3 was used to evaluate the effect on epidermal growth factor-induced Cten expression. Protein expression was quantified by Western blot. H125 and A549 cells were transduced with short-hairpin RNA via lentiviral vector to knockdown expression of Cten. An invitro transwell invasion assay was used to assess the effects of Cten knockdown on cell invasion (n=3 for all experiments). Stimulation of lung cancer cells with epidermal growth factor activated the signal transducer and activator of transcription 3 pathway and induced expression of Cten in all cell lines. Signal transducer and activator of transcription 3 inhibition significantly reduced epidermal growth factor-induced expression of Cten in H125 (P<.0001), H358 (P=.006), and H441 (P=.014) cells in a dose-dependent manner. Knockdown of Cten expression resulted in significant decreases in cellular invasion in both H125 (P=.0036) and A549 (P=.0006) cells. These are the first findings in lung cancer to demonstrate that Cten expression mediates invasion of human lung cancer cells and is upregulated by epidermal growth factor via signal transducer and activator oftranscription 3 pathway. Cten should be considered a potential therapeutic target for lung cancer.