The correlation and role analysis of KCNK2/4/5/15 in Human Papillary Thyroid Carcinoma microenvironment

Abstract

Background: KCNKs, potassium two pore domain channel family K members, can maintain the resting potential, regulate the amplitude and duration of the plateau of the action potential, and change the membrane potential and membrane excitability. Evidence from many studies indicates that KCNKs is abnormally expressed in many solid tumors and plays a regulatory role in the development and malignant progression of cancer. However, the expression pattern and prognostic value of KCNK factors in papillary thyroid carcinoma have not been reported. Methods: In this study, we used the data from databases such as ONCOMINE, GEPIA, Kaplan-Meier Plotter, and cBioPortal to perform bioinformatics analysis of KCNK factors in patients with thyroid cancer. Results: We found that the mRNA expression of KCNK1, KCNK5, KCNK6, KCNK7, and KCNK15 were significantly higher in thyroid cancer tissues than that in normal tissues, while KCNK2, KCNK4, KCNK9, KCNK16 and KCNK17 mRNA levels were decreased compared to normal tissues. And the expression levels of KCNK1/2/4/5/6/7/15 were correlated with the tumor stage. Survival analysis using the Kaplan-Meier Plotter database revealed that KCNK2/3/4/5/12/15 were associated with overall survival (OS) in patients with thyroid cancer. Conclusion: Finally, the results of ROC curves, immunohistochemical staining, immune cell infiltration and kinase / miRNA / transcription factor regulation showed that KCNK2, KCNK4, KCNK5 and KCNK15 levels could be used as biomarkers for PTC diagnosis. This study implied that KCNK2, KCNK4, KCNK5 and KCNK15 are potential targets of precision therapy for patients with thyroid cancer and these genes are new biomarkers for the therapeutic target for thyroid cancer.

Keywords: KCKNs; immune cell infiltration; microenvironment; papillary thyroid carcinoma.

Figure 1

The transcription levels of KCNK factors in thyroid cancer (UALCAN). Compared with normal samples, KCNK1/5/6/7/15 mRNA was overexpressed in TC, and KCNK2/4/9/16/17 mRNA was underexpressed. **p<0.01, *** p<0.001.

Figure 2

Correlation between KCNKs expression and tumor stage in TC patients (UALCAN). Compared with normal tissues, KCNK 1/ 5/6/7/15 expression was positively correlated with the clinical stage, and KCNK 2/4/9 expression was negatively correlated with the clinical stage.*p<0.05, **p<0.01, ***p<0.001.

Figure 3

Prognostic value of mRNA expression of distinct KCNKs family members in thyroid cancer patients (Kaplan-Meier Plotter).

Figure 4

Genetic mutations in KCNKs and their association neighbor genes network of PTC patients (cBioPortal and GeneMANIA). (A) The network contains 65 nodes, including KCNKs factors and the 50 most frequently altered neighbor genes. (B) Protein-protein interaction network of KCNKs. (C) Summary of alterations in differently expressed KCNKs in PTC.

Figure 5

The function of KCNKs factors and the significant genes associated with KCNKs changes were analyzed by various analysis tools. (A) Funrich analysis. (B) Cluego analysis. (C) GSCALite pathway analysis.

Figure 6

Correlations between expression of KCNK2/4/5/15 with immune infiltration level in TC. KCNK2 expression was negatively associated with the infiltration of CD8+ T cells and dendritic cell, and positively associated with the infiltration of purity. The level of KCNK4 expression negatively correlated with the infiltration levels of B cells, CD4+ T cells, macrophages, neutrophils, and dendritic cell in thyroid carcinoma tissues. KCNK5 expression was negatively associated with the infiltration of macrophage, and positively associated with the infiltration of B cells.

Figure 7

Genes differentially expressed in correlation with KCNK2/4/5/15 in thyroid carcinoma (LinkedOmics). (A, D, G, J) The correlation between KCNK2/4/5/15 and differentially expressed genes was analyzed by the Pearson test analysis in volcano plots. (B, C, E, F, H, I, K, L) The heatmap showing the top 50 genes negatively or positively correlated with KCNK2/4/5/15.

Figure 8

ROC curves and immunohistochemistry results of KCNK2, KCNK4, KCNK5, KCNK15. (A) KCNK2, AUC=0.9229 (95%CI: 0.8933-0.9524), p < 0.0001; KCNK4, AUC=0.8591 (95% CI: 0.8246-0.8935), p <0.0001; KCNK5, AUC=0.8445 (95% CI: 0.8038-0.8852), p <0.0001; KCNK15, AUC=0.7815 (95% CI: 0.742-0.821) , p <0.0001. (B) KCNK5 and KCNK15 proteins were higher in PTC tissues and KCNK2 and KCNK4 proteins were lower in PTC, compared to tumor-adjacent tissues, Bar=20 µm.