Background: Colorectal cancer is the third most common cancer globally, and the incidence in younger populations is increasing. Therefore, there is an urgent need to study tumor biomarkers for early diagnosis and prognosis, in order to improve the sensitivity and specificity of current clinical markers. Extracellular vesicles called exosomes, which are cell-secreted vesicles with a size range of 30-200nm, play a role in intercellular communication. Existing literature suggests that tumor-secreted circulating exosomes have potential as tumor biomarkers [1]. The RING finger protein family is an important group of E3 ubiquitin ligases that play a critical role in the development and progression of cancer. RNF208, a member of the RING finger protein family, has been shown to inhibit triple-negative breast cancer metastasis by ubiquitinating and degrading WAVE proteins [2]. However, its role as a plasma exosomal tumor biomarker and molecular mechanism in colorectal cancer have not been reported.

Methods: Potential diagnostic and prognostic biomarkers will be screened through bioinformatics analysis, differential analysis, and univariate/multivariate Cox regression analysis. The efficacy of the biomarkers will be tested using ROC curve analysis. Plasma samples from normal individuals and colorectal cancer patients will be collected clinically, and exosomes will be purified using a reagent kit. Exosome-related phenotypes will be detected through transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blot. The mRNA levels of RNF208 will be measured using quantitative reverse transcription polymerase chain reaction (qPCR) and analyzed in conjunction with clinical data. Pathway enrichment analysis including KEGG, GO, and GSEA will be conducted to investigate the biological behaviors regulated by RNF208. The proliferation ability of tumors will be observed through CCK-8, EdU staining, and subcutaneous tumor transplantation models in nude mice. The invasion ability of tumors will be observed through Transwell assay, cell scratch experiment, and metastasis tumor models in nude mice. Apoptosis and cell cycle distribution will be assessed using flow cytometry (FCM) and Western blot. The impact of RNF208 on the tumor immune microenvironment will be analyzed through CIBERSORT analysis.

Results: Compared to normal individuals, RNF208 mRNA levels are significantly upregulated in plasma exosomes of colorectal cancer patients and associated with poor prognosis. Overexpression of RNF208 in colorectal cancer promotes malignant biological behaviors such as proliferation, migration, and invasion. Aberrant expression of RNF208 in colorectal cancer may be involved in the regulation of the tumor immune microenvironment.

Keywords: RNF208; tumor biomarker; colorectal cancer; proliferation; invasion

References:

1.      Yu, D., Li, Y., Wang, M. et al. Exosomes as a new frontier of cancer liquid biopsy. Mol Cancer 21, 56 (2022).

2.      Pang,Kyoungwha,et al."RNF208, an estrogen-inducible E3 ligase, targets soluble Vimentin to suppress metastasis in triple-negative breast cancers". Nature Communications, vol.10,2019, pp.

Zhang Shanfeng, male, is a senior experimentalist and master's supervisor. He is a member of the Microbiology Society of Henan Province, an active member of the American Association for Cancer Research (AACR), and a lifelong member of the Chinese Society of Biochemistry and Molecular Biology. He serves as an editorial board member for the Journal of Surgery and Implants and the Online Journal of Cardiology Research & Reports (OJCRR), and as a reviewer for Frontiers, Anti-Cancer Agents in Medicinal Chemistry, Current Chemical Biology, and Life Science and Technology. He has published more than 36 SCI papers with a total citation of 821. He has undertaken 5 projects funded by the National Natural Science Foundation of China, and has edited 4 textbooks and monographs. He has obtained 4 utility model patents. He has received the Second Prize of Scientific and Technological Progress in Henan Province and the Special Prize of Higher Education Teaching Achievement Award in Henan Province.

Memberships:

Microbiology Society of Henan Province

American Association for Cancer Research (AACR)

Chinese Society of Biochemistry and Molecular Biology

Editorial Board Member:

Journal of Surgery and Implants

Online Journal of Cardiology Research & Reports (OJCRR)

Reviewer for Journals:

Frontiers

Anti-Cancer Agents in Medicinal Chemistry

Current Chemical Biology

Life Science and Technology

Publications:

More than 36 SCI papers with a total citation of 821

Research Projects:

Undertaken 5 projects funded by the National Natural Science Foundation of China

Books and Monographs:

Editor of 4 textbooks and monographs

Patents:

Obtained 4 utility model patents

Awards:

Second Prize of Scientific and Technological Progress in Henan Province

Special Prize of Higher Education Teaching Achievement Award in Henan Province