Raf-1 proto-oncogene, serine/threonine kinase (Raf1), is a crucial component of the RAS/RAF/MEK/ERK signaling pathway, regulating cell migration, apoptosis, and differentiation. However, research on Raf1 expression and its clinical significance in non-small cell lung cancer (NSCLC) is limited. Here, researchers explored the clinical value and prognostic significance of Raf1 in NSCLC patients after radiotherapy. The study found that Raf1 expression was significantly associated with the invasive and metastatic abilities of lung cancer A549 and H1299 cell lines. Results showed that Raf1 expression was present in 44.5% of NSCLC patient specimens, and Raf1 expression was positively correlated with lymph node metastasis, T stage, and histological poor differentiation. Patients with negative or low Raf1 expression experienced slower disease progression than those with high Raf1 expression. Multivariate analysis indicated that Raf1 was an independent prognostic factor for time to progression (TTP). High Raf1 expression was associated with poorer 3-year overall survival (OS). Raf1 overexpression was associated with early progression of NSCLC. Raf1 may become a novel prognostic factor and potential target for improving the long-term prognosis of NSCLC patients.
Here, researchers performed in vitro gain-of-function analyses to investigate the effects of Raf1 on lung cancer cell invasion and migration. Scratch healing assays showed that Raf1-overexpressing A549 cells exhibited enhanced lateral migration, while Raf1-silenced H1299 cells showed diminished lateral migration (Figure 1). Transwell invasion assays also demonstrated that Raf1-overexpressing A549 cells exhibited enhanced invasiveness, while Raf1-silenced H1299 cells showed diminished invasiveness (Figure 2). In summary, these results indicate that Raf1 can promote the migration and invasion of lung cancer cells.
Figure 1. Wound healing assay showed that Raf1 expression affects the lateral migration in lung cancer cells. (Tian H, et al., 2018)
Figure 2. Transwell invasion assay shows that the Raf1 expression affects the invasion ability in lung cancer cells. (Tian H, et al., 2018)