583P - RHBDL2 promotes non-small cell lung cancer metastasis and osimertinib resistance by activating the RAS/MEK/ERK signaling pathway through interaction with FGFR

Background

Non-small cell lung cancer (NSCLC) is a highly malignant form of cancer, distinguished by prompt metastasis, restricted response to chemotherapy, and unfavorable prognosis. As a result, there is an imperative requirement to investigate novel therapeutic approaches for NSCLC. Rhomboid-like protein 2 (RHBDL2) is overexpressed in various tumor cells and is associated with poor prognosis. However, the relevance of RHBDL2 to NSCLC remains unclear. This study aims to investigate the potential role of RHBDL2 as a diagnostic and prognostic biomarker for NSCLC, as well as its biological functions and molecular mechanisms in NSCLC.

Methods

TCGA, GEO, CTPAC, and HPA datasets were used to compare differential expression and pathological stratification of RHBDL2. Its prognostic and diagnostic role was evaluated using Kaplan-Meier curves and univariate and multivariate Cox regression analysis. In molecular biology experiments, protein expression was measured by immunohistochemical analyses and Western blot analyses. Protein-protein interactions were detected by co-immunoprecipitation assay and GST-pulldown assay. Cell proliferation was assessed by CCK8 assay and colony formation assay. Cell migration was performed by Transwell assays and wound healing assays.

Results

We found that RHBDL2 was highly expressed in human NSCLC cells and tissues, and was significantly correlated with distant metastasis and poor survival of NSCLC patients. Gain- and loss-of-function assays showed that RHBDL2 could accelerate NSCLC metastasis in vitro and in vivo. CO-IP/MS results suggested that RHBDL2 interacted with FGFR. RHBDL2 could directly interact with FGFR and affect its phosphorylation, and promote NSCLC cell migration by activating the downstream RAS/MEK/ERK signaling pathway. In addition, we also found that RHBDL2 was involved in osimertinib resistance through FGFR/RAS pathway.

Conclusions

Our study results indicate that RHBDL2 promotes NSCLC cell migration and osimertinib resistance by interacting with FGFR and thereby activating the RAS/MEK/ERK signaling pathway. Moreover, it can serve as a novel diagnostic and prognostic biomarker for NSCLC patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

This study was funded by National Natural Science Foundation of China (81702887), Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province (2020E10021), Zhejiang Provincial Natural Science Foundation(LY19H310004,LTY21H160001), Scientific and Technological Developing Scheme of Hangzhou City (20191203B49), Science Research Foundation of Zhejiang Health Bureau (2020RC026).

Disclosure

All authors have declared no conflicts of interest.