TEX19 promotes ovarian carcinoma progression and is a potential target for epitope vaccine immunotherapy.

Abstract Aims Testis Expressed 19 (TEX19) is one of cancer/testis antigens identified in recent years and is related to the oncogenesis and progress of several cancers. This study aimed to reveal the role of TEX19 in ovarian cancer (OC) and searched for potential candidate epitope peptides of TEX19 to facilitate clinical application. Main methods TEX19 levels were evaluated by immunohistochemistry (IHC) in 98 human ovarian tissue samples. The correlation of TEX19 levels with patients' clinicopathological features was assessed. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analysis were utilized to detect TEX19 levels in ovarian cell lines and TEX19-deficient cells. The level of TEX19 in OVCAR-3 and A2780 was knocked down by small interfering RNA (siRNA), and loss-of-function assays were used to determine the biological effects of TEX19 on the proliferation, migration, and invasion of OC cells. Subsequently, candidate epitope peptides from TEX19 were predicted and verified by the IEDB database, pepsite2 website, MOE software, and T2 cell binding assay. Key findings TEX19 was significantly upregulated in OC which correlated to higher TNM stage, lymph node involvement, and invasiveness. Knockdown of TEX19 inhibited proliferation, migration, and invasion of OC cells. Additionally, we screened four peptides derived from TEX19 and found TL to be the dominant peptide with the greatest affinity with HLA-A*0201. Significance Our data indicated a cancer-promoting effect of TEX19 in OC and demonstrated that TL could be a potential candidate for an anti-tumor epitope vaccine of OC, suggesting that TEX19 is a promising biomarker and immunotherapeutic target for OC.