BackgroundProstate cancer is the most common tumor in men worldwide, seriously threatening the health of older men, and 5-methylcytosine (m5C) RNA modification has been shown to have a significant impact on the development and progression of various tumors. However, as the most critical methyltransferase for m5c RNA modification, the role of the NSUN members (NSUN1-7) in prostate cancer is unclear.MethodsWe obtained sequencing data of genes and related clinical data of prostate cancer from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database and analyzed the correlation between NSUN members’ expression and prognosis. we found that NSUN2 was closely implicated in the prognosis of prostate cancer, then verified the expression of NSUN2 in clinical samples, and obtained the correlation between NSUN2 and immune cell infiltration through CIBERSORT algorithm and ESTIMATE method. The relationship between NSUN2 copy number variation and immune cell infiltration was further analyzed in the TIMER database and identified signaling pathways associated with NSUN2 expression by GO, KEGG, and GSEA analysis. Finally, we verified the expression of NSUN2 in prostate cancer cell lines and confirmed the role of NSUN2 on the biological behavior of prostate cancer cells by proliferation and migration-related assays.ResultsNOP2 and NSUN2 were upregulated in prostate tumor tissues. NSUN2 expression is closely associated with tumor prognosis. NSUN2 high expression implies poor clinical features, and the NSUN family is significantly associated with tumor stromal score and immune score. Besides, NSUN2 is associated with a variety of immune infiltrating cells (B cells memory, T cells CD4 memory resting, T cells CD4 memory activated, NK cells resting, and so on). High NSUN2 expression lowers the sensitivity of many chemotherapy drugs, such as docetaxel, doxorubicin, fluorouracil, cisplatin, and etoposide. In prostate cancer, the most common type of mutation in NSUN2 is amplification, and NSUN2 copy number variation is closely associated with NSUN2 expression and immune cell infiltration. GSEA analysis showed that the related genes were mainly enriched in ubiquitin-mediated protein hydrolysis, cell cycle, RNA degradation, endometrial cancer, prostate cancer, p53 signaling pathway, and NSUN2 potentiated the proliferation and migration of prostate cancer cells.ConclusionsNSUN2 is highly expressed in prostate cancer, which contributes to the progression of prostate cancer, and is closely implicated in immune cell infiltration and chemotherapy drugs. NSUN2 is expected to be a prospective marker and a new treatment target for prostate cancer.

Cytoskeleton-associated protein 2-like (CKAP2L), a cell cycle-related protein, is correlated to tumor progression in some tumors. But there were no pan-cancer studies on CKAP2L, and its role in cancer immunotherapy is also unclear. The expression levels, expression activity, genomic alterations, DNA methylation and functions of CKAP2L in various tumors, as well as the associations between CKAP2L expression and patient prognosis, chemotherapy sensitivity, and tumor immune microenvironment, were all analyzed in a comprehensive pan-cancer analysis of CKAP2L by various databases, analysis websites, and R software. The experiments were also conducted to verify the analysis results. In the majority of cancers, CKAP2L expression and activity were markedly elevated. Elevated CKAP2L expression led to poor prognostic outcomes in patients, and is an independent risk factor for most tumors. Elevated CKAP2L causes decreased sensitivity to chemotherapeutic agents. Knockdown of CKAP2L significantly inhibited the proliferation and metastasis capacity of the KIRC cell lines and resulted in cell cycle G2/M arrest. In addition, CKAP2L was closely related to immune subtypes, immune cell infiltration, immunomodulators and immunotherapy markers (TMB, MSI), patients with high CKAP2L expression were more sensitive to immunotherapy in the IMvigor210 cohort. The results indicate that CKAP2L is a pro-cancer gene that serves as a potential biomarker for predicting patient outcomes. By inducing cells to transition from the G2 phase to the M phase, CKAP2L may promote cell proliferation and metastasis. Furthermore, CKAP2L is closely related to the tumor immune microenvironment and can be used as a biomarker to predict tumor immunotherapy.

Background: The role of the T cell-activated Rho GTPase activating protein (TAGAP) in immune diseases continues to be explored but has not been yet elucidated for lung adenocarcinoma (LUAD).Methods: The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression dataset (GTEx) databases were used to analyze the difference of TAGAP expression and its correlation with immune cell infiltration, immune checkpoints, and tumor cell stemness scores in pan-cancer and LUAD cohorts. Gene expression single-cell sequencing data from Gene Expression Omnibus (GEO) were used to analyze TAGAP distribution in immune cells. The correlation between TAGAP expression and immune cell markers was validated in 26 pairs of LUAD tissues by Reverse transcription-quantitative PCR (RT-qPCR) and immunohistochemistry. Results: TAGAP was differentially expressed in 27 different cancers tissues and the corresponding adjacent tissues. Its expression level was significantly correlated with immune cell infiltration, immune checkpoints, mDNAsi, and mRNAsi. Moreover, TAGAP was significantly low in LUAD and could be associated with poor prognosis, thereby it can be used as an independent prognostic factor for LUAD. Besides, TAGAP showed a significant positive correlation with B cells, CD4+ T cells, CD8+ T cells, macrophages, neutrophils, and dendritic cells in LUAD. The experimental verification with RT-qPCR and immunohistochemistry showed that TAGAP was significantly positively correlated with CD8 and CD4 expressions. TAGAP expression is linked to a greater response to immune checkpoint blockade treatment in NSCLC. Conclusion: Overall, TAGAP can be a potential LUAD biomarker and might play anti-tumor effects by enhancing the tumor immune cell infiltration in LUAD’s microenvironment, TAGAP might be used as an immunotherapy target to regulate the anti-tumor immune response.

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