Yiming Zhou,1 Rui Chai,2 Yongxiang Wang,3 Xiaojun Yu3 

1Department of Hepatopancreatobiliary Surgery, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, People’s Republic of China; 2General Surgery, Cancer Center, Department of Colorectal Surgery, Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, 310014, People’s Republic of China; 3Department of Gastric Surgery, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, People’s Republic of China

Correspondence: Xiaojun Yu, Email fishyocat@163.com

Background: EIF3D, a key component of the eukaryotic translation initiation factor 3 (EIF3) complex, is critical in selectively translating mRNAs with atypical cap structures. Its relationship with colon adenocarcinoma (COAD) development and immune infiltration, however, remains under-explored. This study delves into EIF3D’s role in COAD using bioinformatics and in vitro experimentation.
Materials and Methods: We analyzed EIF3D expression levels utilizing TCGA, GTEx, CPTAC, and TISIDB databases. The TISCH database and ssGSEA method helped in assessing EIF3D’s link with the tumor immune microenvironment. EIF3D expression in CRC cells was gauged via real-time PCR. Cell proliferation was assessed using CCK8 and colony formation assays, while migration capabilities were tested through Transwell assays. Flow cytometry facilitated cell cycle distribution and apoptosis analysis. ChIP-qPCR identified transcription factors regulating EIF3D, and bulk sequencing explored EIF3D’s pathways in promoting COAD.
Results: EIF3D upregulation is a common feature in various tumors, especially in COAD, correlating with poor prognosis in many cancer types. It showed significant associations with immune cell and cancer-associated fibroblast (CAF) infiltration across multiple tumors. Additionally, it is closely associated with molecular and immune subtypes of multiple tumors, including COAD. Single-cell analyses depicted EIF3D’s distribution and proportion in CRC immune cells. In vitro findings indicated EIF3D knockdown curtailed proliferation and migration, inducing G0/G1 arrest in COAD cells. Moreover, bulk sequencing revealed EIF3D knockdown interferes with multiple cancer-related pathways, likely by curtailing cell cycle and DNA replication activities to regulate cell proliferation.
Conclusion: EIF3D emerges as a potential prognostic biomarker for tumor progression and immune infiltration, particularly in COAD, potentially predicting immunotherapy efficacy. Additionally, EIF3D represents a multifaceted target implicated in COAD’s malignant progression.

Keywords: EIF3D, pan-cancer, tumor immune microenvironment, biomarker, therapeutic target