RASGRP2 is a potential immune-related biomarker and regulates mitochondrial-dependent apoptosis in lung adenocarcinoma

Yongting Liu; Yanhong Ouyang; Ziyang Feng; Zhaohui Jiang; Jiayao Ma; Xin Zhou; Changjing Cai; Ying Han; Shan Zeng; Shanshan Liu; Hong Shen

doi:10.3389/fimmu.2023.1100231

RASGRP2 is a potential immune-related biomarker and regulates mitochondrial-dependent apoptosis in lung adenocarcinoma

Front Immunol. 2023 Feb 3:14:1100231. doi: 10.3389/fimmu.2023.1100231. eCollection 2023.

Authors

Yongting Liu^{1

2}, Yanhong Ouyang^{1

3}, Ziyang Feng^{1

2}, Zhaohui Jiang^{1

2}, Jiayao Ma^{1

2}, Xin Zhou^{1

2}, Changjing Cai^{1

2}, Ying Han^{1

2}, Shan Zeng^{1

2}, Shanshan Liu⁴, Hong Shen^{1

2}

Affiliations

¹ Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China.
² National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China.
³ Department of Emergency, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China.
⁴ Department of Radiotherapy, Tianjin First Central Hospital, Tianjin, China.

Abstract

Background: Ras guanine nucleotide-releasing protein 2 (RASGRP2), one of the guanine nucleotide exchange factors (GEFs), has attracted much attention in recent years. However, the correlation between RASGRP2 and immune infiltration and malignant features in lung adenocarcinoma (LUAD) has rarely been mentioned.

Methods: The Limma package and the LASSO regression model were performed to screen for differentially expressed genes. Data from the TCGA and 5 GEO databases were used to explore the expression level of RASGRP2 in LUAD patients. A weighted co-expression network and LinkFinder module were established to find the related genes of RASGRP2. The ESTIMATE algorithm was used to analyze the correlation between RASGRP2 and immune infiltration in LUAD. Tumor-infiltrating immune cells were sorted and sequenced at the single-cell level to analyze differences in RASGRP2. Real-time PCR and immunohistochemistry were performed in the real-world cohort to verify the expression of RASGRP2 and its correlation with immune-related genes. Clone formation and EdU assays were used to verify the proliferation ability. The proportion of apoptotic cells was analyzed by flow cytometry. Observation of mitochondrial membrane potential (MMP) changes by fluorescence microscopy.

Results: Our results suggested that decreased RASGRP2 was associated with worse clinical parameters and prognosis in LUAD patients. And we constructed a FLI1-HSA-miR-1976-RASGRP2 transcriptional network to support the role of RASGRP2. Enrichment analysis revealed that RASGRP2 was involved in lymphocyte activation and leukocyte adhesion. RASGRP2 was found to be positively correlated with the infiltration of most immune cells, immunoregulators, and chemokines in a subsequent study. Meanwhile, the real-world cohort confirmed that the expression levels of PDCD1, CTLA4, CD40LG, CCL14, CXCR5, and CCR7 were higher in the high-RASGRP2 expression group. Cytological experiments proved that RASGRP2 inhibited cell proliferation in LUAD by regulating mitochondrial-dependent apoptosis.

Conclusion: RASGRP2 was a potential immune-related biomarker of LUAD. In addition, RASGRP2 was involved in the malignant progression of LUAD through the regulation of mitochondrial-dependent apoptosis.

Keywords: LUAD; RASGRP2; TF-miRNA-mRNA regulatory network; immune biomarkers; mitochondrial-dependent apoptosis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adenocarcinoma of Lung*
Algorithms
Apoptosis
Guanine Nucleotide Exchange Factors
Humans
Lung Neoplasms*
Mitochondria

Substances

RASGRP2 protein, human
Guanine Nucleotide Exchange Factors

Grants and funding

This study was supported by six grants from the National Natural Science Foundation of China (No. 81070362, 81172470, 81372629, 81772627, 81874073 & 81974384), two projects from the Nature Science Foundation of Hunan Province (No. 2021JJ31092 & 2021JJ31048), two projects from the CSCO Cancer Research Foundation (No. Y-HR2019-0182 & Y-2019Genecast-043), and three projects from the key R & D Projects of Hainan Province (No. ZDYF2021SHFZ099 & ZDYF022SHFZ086 & ZDYF022SHFZ087).