Data-independent Acquisition Mass Spectrometry Reveals Exosomal LAMC1 as a Key Determinant of Lung Adenocarcinoma...

This study is formulated to reveal the variables affecting the radio-sensitivity in lung adenocarcinoma (LUAD).

LUAD patients show varied radiotherapy responses. While epidermal growth factor receptor (EGFR) mutations are often used to predict sensitivity, their reliability is debated, underscoring the need for better biomarkers.

The aim of this study was to identify key functional proteins that regulate the sensitivity of LUAD to radiotherapy and to assess the potential value of exosomal LAMC1 as a clinical predictive marker.

In this study, 103 LUAD patients receiving concurrent radiotherapy were included to assess the relationship between EGFR mutation and survival. Intrinsic radio-sensitivity and different radio-sensitivities in 14 LUAD cell lines with/out EGFR mutation were examined based on the surviving fraction at 2 Gy (SF2). Data-independent acquisition (DIA) and Liquid chromatography-tandem mass spectrometry (LC-MS/MS)- based proteomics were used to investigate the proteomics of the LUAD cell lines. Subsequently, GO/KEGG enrichment analysis was combined with protein-protein interaction (PPI) network screening for key proteins. Nano-flow cytometry was employed to validate changes in radiosensitivity-associated protein expression within exosomes, while siRNA-mediated knockdown was performed to assess the functional impact of specific proteins on LUAD cells.

EGFR mutations were not significantly associated with progression-free survival (PFS)/overall survival (OS). 14 LUAD cell lines displayed intrinsic variations in SF2, and no difference between the EGFR mutation and wild-type groups was reported. 5425 proteins were identified via DIA in 14 LUAD cell lines. After bio-informatics analysis, LAMC1, ITGB4, ITGA6, and CD44 were the most representative core differential proteins for the radio-sensitivity in LUAD cells. Notably, LAMC1 was confirmed as a radiation-resistant protein. Following radiotherapy, LUAD cells secreted exosomes with reduced LAMC1 levels. Moreover, LAMC1 knockdown significantly affected cellular proliferation and apoptosis following the irradiation.

LAMC1 serves as a critical functional determinant of radiotherapy resistance in LUAD. Its dynamic changes in exosomes demonstrate potential for predicting radiotherapy response, suggesting clinical utility for radiosensitivity assessment and personalized radiotherapy guidance.