Epigenetic modification of Castor zinc finger 1 (CASZ1) is associated with tumor microenvironments and prognosis of clear cell renal cell carcinoma

Abstract

Background: Clear cell renal cell carcinoma (ccRCC) represents the predominant and remarkably diverse form of renal cell carcinoma. The involvement of the Castor zinc finger 1 (CASZ1) gene in adverse prognostic outcomes has been observed across different cancer types. Nevertheless, the specific altered activities and associated multi-omics characteristics of CASZ1 in ccRCC remain unelucidated.

Method: In order to explore the expression of CASZ1, evaluate its prognostic significance, and aid in the therapeutic decision-making process for patients with ccRCC, The Cancer Genome Atlas (TCGA), Gene expression omnibus (GEO), and The Human Protein Atlas (HPA) databases were utilized to gather data on clinicopathological data, prognostic information, genomic, methylomic and immunomic data. Additionally, the Genomics of Drug Sensitivity in Cancer (GDSC) database provided information on drug sensitivity.

Results: CASZ1 expression was found to be significantly reduced in ccRCC and was associated with unfavorable pathological characteristics and a bleak prognosis. Diminished CASZ1 mRNA levels were notably correlated with heightened cytosine-phosphate-guanine (CpG) methylation, indicating a poorer prognosis for patients with increased methylation. Examination of RNA-seq data from TCGA indicated that the CASZ1-high expression subgroup displayed heightened immune cell infiltration and increased expression of immune checkpoint markers, potentially suggesting a more favorable response to immunotherapy. Furthermore, data from the GDSC database indicated that the CASZ1-low expression subgroup might exhibit greater sensitivity to anti-angiogenetic treatments, such as Sunitinib and Axitinib.

Conclusions: These results indicate that CASZ1 may function as a biomarker for distinguishing various tumor microenvironment phenotypes, predicting prognosis, and assisting in treatment decisions for individuals with ccRCC.

Figure 1

Castor zinc finger 1 (CASZ1) mRNA and protein expression was lower in renal cell carcinoma (RCC) tissues than that in normal kidney tissues. Low CASZ1 expression was associated with several clinicopathological characteristics and poor prognosis in clear cell renal cell carcinoma (ccRCC). (A) CASZ1 mRNA expression in tumor and normal tissues from pan-cancer data of The Cancer Genome Atlas (TCGA). *P<0.05, **P<0.01, ***P<0.001. (B) CASZ1 mRNA expression in tumor and normal tissues from ccRCC obtained from Gene Expression Omnibus (GEO) database, including GSE53757, GSE40435 and GSE66272. ****P<0.0001. (C) Representative immunohistochemical staining of CASZ1 in normal kidney tissue and ccRCC tissue from HPA (The Human Protein Atlas). (D) Representative immunohistochemical staining of CASZ1 in adjacent normal tissues and ccRCC tissue from our institution. (E) The percentage of positive area of tumor tissue was significantly lower than that of adjacent normal tissue. (F) CASZ1 mRNA expression was associated with pT stage, metastatic status and tumor grading in ccRCC, but not with pN stage. CASZ1 mRNA expression was associated with pT stage and pN stage in papillary renal cell carcinoma (pRCC), but not with metastatic status. CASZ1 mRNA expression was associated with pT stage in chromophobe renal cell carcinoma (chRCC), but not with pN stage.*P<0.05, **P<0.01,***P<0.001, ****P<0.0001. (G) Kaplan–Meier analysis of the association between CASZ1 expression and OS in ccRCC, pRCC, chRCC.

Figure 2

Castor zinc finger 1 (CASZ1) expression was associated with DNA methylation modification in clear cell renal cell carcinoma (ccRCC). (A) CpG-aggregated methylation value of CASZ1 in tumor and normal tissues from pan-cancer data of The Cancer Genome Atlas (TCGA). *P<0.05, **P<0.01, ***P<0.001,****P<0.0001. (B) The correlation of CASZ1 expression and the expression of DNA methylation-related genes. (C) The association of methylation level with gene subregions. (D) The DNA methylation level of different probes between normal and tumor tissues. (E) The association between CASZ1 expression and these probes’ methylation levels in ccRCC. (F) The relationship between the prognosis and the methylation levels of these probes in ccRCC.

Figure 3

The Castor zinc finger 1 (CASZ1)-low and CASZ1-high subgroups had different enriched functions and pathways and distinct CASZ1 expression patterns could indicate potential therapeutic strategies in clear cell renal cell carcinoma (ccRCC). (A) Differential genes between the CASZ1-low and CASZ1-high subgroups and 50 up-regulated genes and 50 down-regulated genes with the largest differential changes. (B) KEGG pathway enrichment analysis and GO enrichment analysis of genes up-regulated in the CASZ1-low subgroup and genes up-regulated in the CASZ1-high subgroup. (C) Immune cell score in the CASZ1-low and CASZ1-high subgroups and the percentage abundance of tumor-infiltrating immune cells in each sample.*P<0.05, **P<0.01, ***P<0.001. (D) The expression of immune checkpoints in the CASZ1-low and CASZ1-high subgroups. *P<0.05, **P<0.01, ***P<0.001. (E) The difference of the expression of CASZ1 between Non-Responder (NR) and Responder (R). (F) Distribution of Sunitinib, Pazopanib and Axitinib IC50 scores in the CASZ1-low and CASZ1-high subgroups. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.