Clinicopathological Characteristics of TZAP Expression in Colorectal Cancers

CircRNF10 triggers a positive feedback loop to facilitate progression of glioblastoma via redeploying the ferroptosis defense in GSCs

BACKGROUND

Glioma exhibit heterogeneous susceptibility for targeted ferroptosis. How circRNAs alterations in glioma promote iron metabolism and ferroptosis defense remains unclarified.

METHODS

The highly enriched circRNAs in glioblastoma (GBM) were obtained through analysis of sequencing datasets. Quantitative real-time PCR (qRT-PCR) was used to determine the expression of circRNF10 in glioma and normal brain tissue. Both gain-of-function and loss-of-function studies were used to assess the effects of circRNF10 on ferroptosis using in vitro and in vivo assays. The hypothesis that ZBTB48 promotes ferroptosis defense was established using bioinformatics analysis and functional assays. RNA pull-down and RNA immunoprecipitation (RIP) assays were performed to examine the interaction between circRNF10 and target proteins including ZBTB48, MKRN3 and IGF2BP3. The posttranslational modification mechanism of ZBTB48 was verified using coimmunoprecipitation (co-IP) and ubiquitination assays. The transcription activation of HSPB1 and IGF2BP3 by ZBTB48 was confirmed through luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays. The stabilizing effect of IGF2BP3 on circRNF10 was explored by actinomycin D assay. Finally, a series of in vivo experiments were performed to explore the influences of circRNF10 on the glioma progression.

RESULTS

A novel circular RNA, hsa_circ_0028912 (named circRNF10), which is significantly upregulated in glioblastoma tissues and correlated with patients' poor prognosis. Through integrated analysis of the circRNA-proteins interaction datasets and sequencing results, we reveal ZBTB48 as a transcriptional factor binding with circRNF10, notably promoting upregulation of HSPB1 and IGF2BP3 expression to remodel iron metabolism and facilitates the launch of a circRNF10/ZBTB48/IGF2BP3 positive feedback loop in GSCs. Additionally, circRNF10 can competitively bind to MKRN3 and block E3 ubiquitin ligase activity to enhance ZBTB48 expression. Consequently, circRNF10-overexpressed glioma stem cells (GSCs) display lower Fe2+ accumulation, selectively priming tumors for ferroptosis evading.

CONCLUSION

Our research presents abnormal circRNAs expression causing a molecular and metabolic change of glioma, which we leverage to discover a therapeutically exploitable vulnerability to target ferroptosis.

The Roles of Zinc Finger Proteins in Colorectal Cancer

Despite colorectal cancer remaining a leading worldwide cause of cancer-related death, there remains a paucity of effective treatments for advanced disease. The molecular mechanisms underlying the development of colorectal cancer include altered cell signaling and cell cycle regulation that may result from epigenetic modifications of gene expression and function. Acting as important transcriptional regulators of normal biological processes, zinc finger proteins also play key roles in regulating the cellular mechanisms underlying colorectal neoplasia. These actions impact cell differentiation and proliferation, epithelial-mesenchymal transition, apoptosis, homeostasis, senescence, and maintenance of stemness. With the goal of highlighting promising points of therapeutic intervention, we review the oncogenic and tumor suppressor roles of zinc finger proteins with respect to colorectal cancer tumorigenesis and progression.

Clinical Characteristics of TZAP (ZBTB48) in Hepatocellular Carcinomas from Tissue, Cell Line, and TCGA

Background and Objectives: ZBTB48 is a telomere-related protein that has been renamed telomeric zinc finger-associated protein (TZAP). It favorably binds to elongated telomeres to regulate their appropriate length. However, TZAP expression has not been investigated in hepatocellular carcinomas (HCC). Materials and Methods: The clinical significance of TZAP expression in 72 HCC was investigated. Additionally, its findings were supported by open big data and cancer cell lines. Results: TZAP expression level was not associated with the clinical parameters of HCC. TZAP expression induced a poorer survival result (overall survival, p = 0.020; disease-free survival, p = 0.012). TCGA data showed TZAP expression was more frequently found in HCCs with hepatitis C infection (p = 0.023). However, TCGA data revealed that TZAP expression did not predict HCC prognosis. In a cell line study, TZAP inhibition via siRNA suppressed PLC/PRF/5 cell growth; however, cell viability was increased in HepG2 cells. Conclusions: We presented the clinical and prognostic values of TZAP expression in HCC tissues and cancer cell lines. Additionally, the TCGA results also revealed a significant role for TZAP expression. TZAP expression may involve HCC progression and its prognosis.

Zbtb34 promotes embryonic stem cell proliferation by elongating telomere length

Zbtb34 is a novel zinc finger protein, which is revealed by biological software analysis to have 3 zinc fingers, but its functions remain unknown. In this study, mouse Zbtb34 cDNA was amplified by PCR and inserted into the plasmid pEGFP-N1 to generate Zbtb34-EGFP fusion protein. The upregulation of Zbtb34 in mouse embryonic stem cells promoted telomere elongation and increased cell proliferation. In order to understand the above phenomena, the telomere co-immunoprecipitation technique was employed to investigate the relationship between Zbtb34 and telomeres. The results indicated that Zbtb34 could bind to the DNA sequences of the telomeres. Alanine substitution of the third zinc finger abolished such binding. Since Pot1 is the only protein binding to the single-stranded DNA at the end of the telomeres, we further investigated the relationship between Zbtb34 and Pot1. The results revealed that the upregulation of Zbtb34 decreased the binding of Pot1b to the telomeres. Through the upregulation of Pot1b, the binding of Zbtb34 to the telomeres was also reduced. In conclusion, we showed that the main biological function of Zbtb34 was to bind telomere DNA via its third ZnF, competing with Pot1b for the binding sites, resulting in telomere elongation and cell proliferation.

Mass Spectrometry-Based Quantitative Proteomics Analysis for Better Understanding of Telomeric Zinc Finger-Associated Protein-Induced Pathogenesis in Cardiomyocytes

Telomere length is highly related to cardiovascular diseases. Telomeric zinc finger-associated protein (TZAP) directly binds to telomeric TTAGGG repeats via zinc finger domains and triggers the initiation of the telomere trimming process. However, proteomics analysis of TZAP in cardiomyocytes is slightly unknown. In our study, TZAP was overexpressed by adenovirus transfection in cultured H9c2 cardiomyocytes, and then mass spectrometry-based quantitative proteomics research strategies, including Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, subcellular localizations, predicted functional domains, and protein-protein interaction (PPI) analysis, were performed to explore TZAP-induced potential pathogenesis in cardiomyocytes. A total of 184 upregulated and 228 downregulated differentially expressed proteins (DEPs) were identified among identified 5693 quantifiable proteins in TZAP-overexpressed cardiomyocytes. These DEPs were mainly distributed in the nucleus, cytoplasm, and plasma membrane. DEPs were enriched in biological processes including cardiac muscle cell contraction, acute inflammatory response, cell-cell junction assembly, and macromolecule biosynthetic process. They were enriched in 9 KEGG pathways, including Hippo signaling pathway, protein digestion and absorption, and cytokine receptor interaction, and enriched in 17 protein domains, including translation initiation factor 1A/IF-1, class I histocompatibility antigen, and zinc finger. PPI analysis indicated that TZAP interacted with NDUFC2, Gja1, and HDAC2. Further, as proteins closely related to cardiovascular function, the mRNA levels of BRD4, Gja1, HDAC2, MAP2K3, Plakophilin 4, and Syndecan 1 significantly decreased, while Trpm7, clusterin, and NDUFC2 remarkably increased in TZAP-overexpressed cardiomyocytes by RT-PCR assay, which were consistent with the proteomics analysis. Collectively, we provided candidate proteins and enrichment pathways in TZAP-overexpressed cardiomyocytes, which need further investigation.

Prognostic Value of Telomeric Zinc Finger-Associated Protein Expression in Adenocarcinoma and Squamous Cell Carcinoma of Lung

Background and Objectives: Telomeric zinc finger-associated protein (TZAP) is a telomere regulation protein, previously known as ZBTB48. It binds preferentially to elongated telomeres, competing with telomeric repeat factors 1 and 2. TZAP expression may be associated with carcinogenesis, however; this study has not yet been performed in lung cancer. In this study, we examined the clinicopathological and prognostic values of TZAP expression in non-small cell lung cancer (NSCLC). Materials and Methods: Data were collected from The Cancer Genome Atlas. The clinical and prognostic values of TZAP for NSCLC were examined in adenocarcinoma (AD) and squamous cell carcinoma (SCC). Results: TZAP expression significantly increased in NSCLC tissues compared with normal tissues. In AD, TZAP expression was lower in patients with higher T stage (p = 0.005), and was associated with lymph node stage in SCC (p = 0.005). Survival analysis showed shorter disease-free survival in AD patients with lower TZAP expression (p = 0.047). TZAP expression did not have other clinical or prognostic value for AD and SCC. Conclusions: TZAP expression is a potential prognostic marker for NSCLC, especially in patients with AD.

Yes-associated protein 1 as a prognostic biomarker and its correlation with telomerase in various cancers

Objectives

The aims of this study were to investigate the expression of Yes-associated protein 1 (YAP1), its prognostic significance, and the correlation between YAP1 and telomerase in various cancers.

Methods

The Gene Expression Profiling Interactive Analysis database was used to analyze RNA sequencing data and the survival rate of patients with various cancers in The Cancer Genome Atlas (TCGA) database. PrognoScan was used to analyze the prognostic value of YAP1 expression in various cancers. Tumor Immune Estimation Resource was used to determine the correlation between YAP1 expression and telomerase in various cancer types based on TCGA data.

Results

The analysis suggested that YAP1 was differentially expressed between tissues of various cancers and non-tumor tissues. High YAP1 expression was also related to a poor prognosis in adrenocortical carcinoma, bladder urothelial carcinoma, and pancreatic adenocarcinoma. Moreover, YAP1 expression was correlated with the expression of telomerase reverse transcriptase and telomerase RNA component in various cancer types.

Conclusion

These results suggest that YAP1 is a potential biomarker with prognostic significance and relevance for oncogene research in various cancer types. The correlation between the expression of YAP1 and telomere-associated genes will help to understand their cancer-promoting mechanisms and interactions.

Telomeric zinc-finger associated protein (TZAP) in cancer biology: friend or foe?

The new identified protein telomeric zinc-finger associated protein (TZAP) is a negative regulator of telomere length. Since telomere length and telomere maintenance mechanisms are essential to cancer progression, TZAP is considered a new player in cancer biology. Here we aimed to analyze TZAP using the Cancer Genome Atlas data in a Pan-Cancer approach. We gathering data from TCGA Pan-Cancer studies utilizing cBioPortal, GEPIA and UALCAN. In total we analyzed 33 types of cancer (n=9664) and their respective controls (n=711). TZAP is transcribed in all cancers but less than 5% of all tumors show any somatic changes. TZAP was downregulated in kidney chromophobe carcinoma, and upregulated in esophageal cancer, head and neck squamous cell carcinomas, kidney renal clear cell carcinoma and in liver hepatocellular carcinoma. Globally, TZAP expression is related to favorable prognosis, associated to better overall and disease-free survival. Looking to specific tumors, TZAP expression has a dual behavior. Its downregulation is associated with poor prognosis in cervical squamous cell carcinoma, in kidney renal clear cell carcinoma, kidney papillary cell carcinoma, lung adenocarcinoma and pancreas adenocarcinoma. On the contrary, in adrenocortical carcinoma, colon and rectal cancer, brain lower grade glioma and prostate adenocarcinoma the upregulation of TZAP is related with poor prognosis. TZAP expression has a positive correlation with TRF1 and TRF2 in normal tissue but not in cancer. Our analyses indicate that TZAP has an important role in oncology and may be considered as a potential biomarker.