Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer.

Abstract

BACKGROUND:

The study examines the function of hypoxia-mediated down-regulation of microRNAs (miRNAs) (mir-30c, mir-135a, and mir-27a) in the process of bladder cancer immune escape.

METHODS:

Quantitative Real-time PCR (qRT-PCR) was carried out to determine gene expression levels of Drosha and Dicer under hypoxia treatment, while western blotting and flow cytometry were used to determine protein expression. Seven reported miRNAs were identified via qRT-PCR assay. Flow cytometry detection of CD3/CD4/CD8-positive expression and statistics. Enzyme-linked immunosorbent assay (ELISA) detected cellular immune factors content. Cell apoptosis was checked via flow cytometry assay. Luciferase report assay and western blot assays were both used to verify the relationship between miRNAs and Casitas B-lineage lymphoma proto-oncogene b (Cbl-b). The animal model was established and Hematoxylin-eosin (HE) staining, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, and immunohistochemistry (IHC) assays were separately used to verify the conclusions.

RESULTS:

The CD3 + /CD4 + expression was increased in the hypoxia group, while CD3 + /CD8 + expression, the cellular immune factors content Interleukin-2 (IL-2) and Tumor Necrosis Factor-α (TNFα) along with the cell apoptosis were suppressed. The protein expression of Cbl-b was found to be up-regulated in the hypoxia group. After constructing the overexpression/ knockdown of Cbl-b in peripheral blood mononuclear cell (PBMC), Cbl-b has been found to promote tumor immune escape in bladder cancer. Furthermore, Cbl-b had been identified as the co-targets of mir-30c, mir-135a, and mir-27a and down-regulation of miRNA biogenesis promotes Cbl-b expression and deactivating T cells in vitro/in vivo.

CONCLUSION:

Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer, which could bring much more advance to the medical research on tumors.

• Authors: Y Zhao, Z Shi, Z Hao, J Zhou, C Han, R Li, Q Lv, Y Liu, C Liang
• Journal: Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico (Clin Transl Oncol) Vol. 23 Issue 8 Pg. 1678-1687 (Aug 2021) ISSN: 1699-3055 [Electronic] Italy
• PMID: 33625672 (Publication Type: Journal Article)

Chemical References

• Adaptor Proteins, Signal Transducing
• CD3 Complex
• CD4 Antigens
• CD8 Antigens
• Interleukin-2
• MAS1 protein, human
• MicroRNAs
• Proto-Oncogene Mas
• Tumor Necrosis Factor-alpha
• CBLB protein, human
• Proto-Oncogene Proteins c-cbl
• DICER1 protein, human
• DROSHA protein, human
• Ribonuclease III
• DEAD-box RNA Helicases

Topics

• Adaptor Proteins, Signal Transducing (genetics)
• Animals
• Apoptosis
• CD3 Complex (metabolism)
• CD4 Antigens (metabolism)
• CD8 Antigens (metabolism)
• DEAD-box RNA Helicases (genetics)
• Disease Models, Animal
• Down-Regulation (immunology)
• Gene Expression Regulation, Neoplastic
• Humans
• Interleukin-2 (metabolism)
• Leukocytes, Mononuclear (metabolism)
• Male
• Mice, Inbred C57BL
• MicroRNAs (biosynthesis, metabolism)
• Prospective Studies
• Proto-Oncogene Mas
• Proto-Oncogene Proteins c-cbl (genetics)
• Random Allocation
• Ribonuclease III (genetics)
• Tumor Escape (immunology)
• Tumor Hypoxia (immunology)
• Tumor Necrosis Factor-alpha (metabolism)
• Up-Regulation
• Urinary Bladder Neoplasms (immunology, metabolism)
• Mice