# A Novel Mitochondria‐Associated Programmed Cell Death–Related Prognostic Model and Validation of Oncogene INHBB in Colorectal Cancer

## TL;DR

This study identifies a new prognostic model for colorectal cancer based on mitochondria-related genes and shows that the INHBB gene promotes cancer growth.

## Contribution

A novel mitochondria-associated programmed cell death-related prognostic model and experimental validation of the oncogenic role of INHBB in colorectal cancer.

## Key findings

- A prognostic model using four mtPCD-related genes (ACSL6, INHBB, GPR15, SRPX) was developed with moderate predictive accuracy.
- INHBB was found to be upregulated in CRC cells and its downregulation reduced cancer cell proliferation and migration.
- Significant differences in immune infiltration and drug sensitivity were observed between high- and low-risk groups.

## Abstract

The objective of this study is to explore mitochondria‐associated programmed cell death (mtPCD)–related key biomarkers for patients with colorectal cancer (CRC).

CRC‐related datasets were obtained from the GEO and TCGA databases, and mitochondria‐related genes (MitoRGs) and PCD‐related genes (PCDRGs) were acquired from the MitoCarta database or pertinent literature. After differentially expressed gene (DEG) screening, the DEmtPCD coexpressed genes were identified. Then, consensus clustering analysis was conducted, followed by GSEA and immune infiltration analysis. In addition, a prognostic model was constructed, and then, immune infiltration analysis, GSEA, and drug sensitivity analysis were carried out. The qRT‐PCR and western blot were employed to determine the expression of key genes. Finally, a loss‐of‐function experiment was applied to investigate the influence of INHBB on CRC in vitro.

A total of 2118 DEGs were screened, and then, 64 DEmtPCD coexpressed genes were obtained. Subsequently, two clusters, including C1 and C2, were identified, and patients in the C1 group had better survival outcomes. In addition, a prognostic model was constructed based on four key genes, namely, ACSL6, INHBB, GPR15, and SRPX. Also, the area under the curves (AUCs) for overall survival (OS) at 1, 3, and 5 years were 0.667, 0.665, and 0.603 in the TCGA set, separately, and 0.759, 0.766, and 0.662, separately, in the GSE17537 dataset. The total fraction of nine immune cells showed a significant difference between the low‐ (L) and high (H)‐risk groups, such as neutrophils, activated NK cells, and activated dendritic cells. Also, there was a significant difference in TIDE scores between the H‐ and L‐risk groups, and APC was the most significantly mutated gene in both the H‐ and L‐risk groups. IC50 value of some chemotherapeutic agents showed a significant difference between the L‐ and H‐risk groups, containing AZD1332‐1463, IGF1R‐3801‐1738, and XAV939‐1268. The expression levels of ACSL6, GPR15, and INHBB were significantly elevated in CRC cells compared to those in NCM460 cells, while SRPX significantly decreased. Notably, downregulation of INHBB effectively alleviated the tumorigenesis of SW620 cells.

A prognostic model was constructed based on four key mtPCD‐associated genes, namely, ACSL6, INHBB, GPR15, and SRPX. INHBB was upregulated in CRC, and the alleviation of INHBB suppressed the proliferation and migration of CRC cells.