Expression of myeloid zinc finger 1 and the correlation to clinical aspects of oral squamous cell carcinoma

The Role of Zinc Finger Proteins in Various Oral Conditions

The zinc finger proteins (ZNFs) are essential transcription factors, and the genes encoding them constitute about 3% of the entire human genome. They are involved in the development of several tissues, and any alterations in their structure may promote chronic conditions like diabetes and tumorigenesis. Lately, their role in the development, progression, and metastasis of Oral Squamous Cell Carcinoma (OSCC), Epithelial Dysplasia, Oral Lichen Planus, and Periodontitis has been found. The present review aims to describe their role in various oral conditions. Electronic databases like Medline (PubMed) and Scopus were searched for original studies related to the role of ZNFs in various oral conditions. It yielded 48 studies included in the review. It was found that the ZNFs influenced chronic conditions like Oral Cancer and Periodontitis. They act both as tumor suppressors and oncogenes and have an anti-inflammatory effect. The knowledge from the present review may be utilized in designing drugs that prevent unusual expression of specific ZNFs. Besides, they may be applied as prognostic markers due to their high expression specificity in some tumors.

Cigarette smoke modulates binding of the transcription factor MZF1 to the VEGF promoter and regulates VEGF expression in dependence of genetic variation SNP 405

BACKGROUND

Vascular endothelial growth factor (VEGF) affects carcinogenesis of the upper aerodigestive tract. Cigarette smoke (CSE) influences VEGF-gene regulation. The single nucleotide polymorphism +405 G/C (SNP +405 G/C) and the transcriptional factor (TF) myeloid zinc finger 1 (MZF1) are endogenic regulators of the VEGFpromoter as the polymorphism 405 potentially affects binding of the transcription factor MZF1. Therefore, this in vitro study analysed cancer cells of the upper aerodigestive tract after CSE incubation concerning MZF1-binding specificity and VEGF expression in dependency of VEGF polymorphism +405 G/C compared to wild type (wt).

METHODS

In human alveolar epithelial-like type-II cells (A549) and oral squamous cell cancer cells (HNSCCUM-02T) SNP +405 G/C- and MZF1-dependent VEGF promoter activity and VEGF expression were analysed by qRT-PCR and Western blot after incubation with 10% CSE. Temporary knock-down of MZF1 was performed using siRNA. MZF1 binding was analysed by Co-Chromatin-Immunoprecipitation (Co-ChiP) (each test n = 3).

RESULTS

We found a stronger MZF1 binding to VEGF polymorphism 405 in A549 cells (P < .05) compared to HNSCCUM-02T cells (P = .02), where MZF1 binding was reduced. MZF1 knock out reduced VEGF promoter activity in HNSCCUM-02T cells, showing the relevance of the factor for transcriptional activation of the VEGF promoter. Finally, we found that CSE increases promoter activity in both cell lines and no significant differences between the two analysed polymorphisms concerning their activating capacity.

CONCLUSION

In summary, both VEGF promoter polymorphisms are similar effective in terms of transcriptional activity, and MZF1 is a transcriptional activator of VEGF promoter. Moreover, cigarette smoke increases MZF1 binding of VEGF-promoter and directly affects VEGF-gene regulation.

MZF1 and SCAND1 Reciprocally Regulate CDC37 Gene Expression in Prostate Cancer

Cell division control 37 (CDC37) increases the stability of heat shock protein 90 (HSP90) client proteins and is thus essential for numerous intracellular oncogenic signaling pathways, playing a key role in prostate oncogenesis. Notably, elevated expression of CDC37 was found in prostate cancer cells, although the regulatory mechanisms through which CDC37 expression becomes increased are unknown. Here we show both positive and negative regulation of CDC37 gene transcription by two members of the SREZBP-CTfin51-AW1-Number 18 cDNA (SCAN) transcription factor family—MZF1 and SCAND1, respectively. Consensus DNA-binding motifs for myeloid zinc finger 1 (MZF1/ZSCAN6) were abundant in the CDC37 promoter region. MZF1 became bound to these regulatory sites and trans-activated the CDC37 gene whereas MZF1 depletion decreased CDC37 transcription and reduced the tumorigenesis of prostate cancer cells. On the other hand, SCAND1, a zinc fingerless SCAN box protein that potentially inhibits MZF1, accumulated at MZF1-binding sites in the CDC37 gene, negatively regulated the CDC37 gene and inhibited tumorigenesis. SCAND1 was abundantly expressed in normal prostate cells but was reduced in prostate cancer cells, suggesting a potential tumor suppressor role of SCAND1 in prostate cancer. These findings indicate that CDC37, a crucial protein in prostate cancer progression, is regulated reciprocally by MZF1 and SCAND1.

Myeloid Zinc Finger 1 and GA Binding Protein Co-Operate with Sox2 in Regulating the Expression of Yes-Associated Protein 1 in Cancer Cells

The transcription factor (TF) yes-associated protein 1 (YAP1) is a major effector of the tumor suppressive Hippo signaling pathway and is also necessary to maintain pluripotency in embryonic stem cells. Elevated levels of YAP1 expression antagonize the tumor suppressive effects of the Hippo pathway that normally represses YAP1 function. High YAP1 expression is observed in several types of human cancers and is particularly prominent in cancer stem cells (CSCs). The stem cell TF Sox2, which marks and maintains CSCs in osteosarcomas (OSs), promotes YAP1 expression by binding to an intronic enhancer element and YAP1 expression is also crucial for the maintainance of OS stem cells. To further understand the regulation of YAP1 expression in OSs, we subjected the YAP1 intronic enhancer to scanning mutagenesis to identify all DNA cis-elements critical for enhancer function. Through this approach, we identified two novel TFs, GA binding protein (GABP) and myeloid zinc finger 1 (MZF1), which are essential for basal YAP1 transcription. These factors are highly expressed in OSs and bind to distinct sites in the YAP1 enhancer. Depletion of either factor leads to drastically reduced YAP1 expression and thus a reversal of stem cell properties. We also found that YAP1 can regulate the expression of Sox2 by binding to two distinct DNA binding sites upstream and downstream of the Sox2 gene. Thus, Sox2 and YAP1 reinforce each others expression to maintain stemness and tumorigenicity in OSs, but the activity of MZF1 and GABP is essential for YAP1 transcription. Stem Cells 2017;35:2340-2350.

Cathepsin B Expression and the Correlation with Clinical Aspects of Oral Squamous Cell Carcinoma

Background

Cathepsin B (CTSB), a member of the cathepsin family, is a cysteine protease that is widely distributed in the lysosomes of cells in various tissues. It is overexpressed in several human cancers and may be related to tumorigenesis. The main purpose of this study was to analyze CTSB expression in oral squamous cell carcinoma (OSCC) and its correlation with patient prognosis.

Methodology/Principal Findings

Tissue microarrays were used to detect CTSB expression in 280 patients and to examine the association between CTSB expression and clinicopathological parameters. In addition, the metastatic effects of the CTSB knockdown on two oral cancer cell lines were investigated by transwell migration assay. Cytoplasmic CTSB expression was detected in 34.6% (97/280) of patients. CTSB expression was correlated with positive lymph node metastasis (p = 0.007) and higher tumor grade (p = 0.008) but not with tumor size and distant metastasis. In addition, multivariate analysis using a Cox proportional hazards model revealed a higher hazard ratio, demonstrating that CTSB expression was an independent unfavorable prognostic factor in buccal mucosa carcinoma patients. Furthermore, the Kaplan–Meier curve revealed that buccal mucosa OSCC patients with positive CTSB expression had significantly shorter overall survival. Moreover, treatment with the CTSB siRNA exerted an inhibitory effect on migration in OC2 and CAL27 oral cancer cells.

Conclusions

We conclude that CTSB expression may be useful for determining OSCC prognosis, particularly for patients with lymph node metastasis, and may function as a biomarker of the survival of OSCC patients in Taiwan.