Opa-Interacting Protein 5 Expression in Human Glioma Tissues Is Essential to the Biological Function of U251 Human Malignant Glioma Cells

Abstract

Opa-interacting protein 5 (OIP5) is a member of the cancer-testis antigen (CTA) family that elicits a spontaneous antitumor immune response. The failure of current immunotherapies for glioma has prompted the search for novel biomarkers that may be utilized as therapeutic targets. This study aimed to investigate whether OIP5 serves as a target for malignant glioma immunotherapy. Glioma specimens from 53 adult patients were evaluated for OIP5 expression by immunohistochemical (IHC) staining, and the correlation of OIP5 expression with World Health Organization (WHO) tumor grade was analyzed. Endogenous expression of OIP5 in glioma cell lines was determined via real-time polymerase chain reaction (RT-PCR). Using lentiviral siOIP5, the effect of OIP5 gene knockdown on proliferation, cell cycle, and apoptosis in U251 glioma cells was studied. The results show that OIP5 is overexpressed in glioma tissues and is correlated with WHO tumor grade ( P < 0.001). However, OIP5 protein expression is barely detectable in normal adult brain tissues. MTT assays and analysis using the Celigo Imaging Cytometry System reveal that the silencing of OIP5 inhibits U251 cell growth. Cell cycle assays and Annexin V staining show that OIP5 silencing disrupts the balance of the cell cycle and increases U251 cell death. These results indicate that OIP5 is upregulated in malignant glioma specimens but barely detected in normal brain tissues. OIP5 knockdown inhibits the biological function of glioma cells, reinforcing that OIP5 may serve as an immunotherapeutic target for malignant glioma.

Mitotic Spindle Positioning (MISP) Facilitates Colorectal Cancer Progression by Forming a Complex with Opa Interacting Protein 5 (OIP5) and Activating the JAK2-STAT3 Signaling Pathway

“…This search highlighted OIP5 as a protein associated with MISP. Notably, OIP5 has been previously reported to be highly expressed in various cancers, including CRC, hepatocellular carcinoma, renal cell carcinoma, bladder cancer, breast cancer, and glioma [ 33 , 34 , 35 , 36 , 37 , 38 ]. OIP5, also known as LINT-25, interacts with lamina-associated polypeptide 2α (LAP2α), a nuclear protein involved in chromatin binding during the cell cycle [ 39 ].…”

The role of OIP5 in the carcinogenesis and progression of ovarian cancer

“…Abnormal expression of genes in cancer lead to tumorigenesis [ 19 , 20 ]. Previous studies have shown that OIP5 is highly expressed in various human malignant tumors, such as breast cancer [ 10 ], malignant glioma [ 21 ], liver cancer [ 14 ], and bladder cancer [ 22 ], and can cause corresponding immune responses in tumor patients. Gong et al confirmed that OIP5 is related to the infiltration of T cells, B cells, macrophages and other immune cells in renal clear cell carcinoma and is a potential immunotherapeutic target for renal clear cell carcinoma [ 23 ].…”

Prognostic and Therapeutic Potential of the OIP5 Network in Papillary Renal Cell Carcinoma

“…Opa interacting protein 5 (OIP5) was discovered as an Opa (Neisseria gonorrhoeae opacity-associated) interacting protein [16]. The protein is highly enriched in human testis (https://www.proteinatlas.org/ENSG00000104147-OIP5/tissue, accessed on 1 August 2021) [17]; its upregulation is associated with adverse clinical features in multiple cancer types, including leukemia [18], ccRCC [19], glioma [20], and the cancers of the liver [21,22], lung [23], breast [24], gastric [25,26], and bladder [27][28][29][30]. Functionally, knockdown of OIP5 was reported to attenuate the proliferation of bladder cancer cells [29], as well as colorectal and gastric cells in vitro [25].…”