Zinc Finger Protein X-linked Expression Research Articles

Circ_0000520 contributes to triple‐negative breast cancer progression through mediating the miR‐1296/ZFX axis

BackgroundTriple‐negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with a high incidence of local recurrence and metastasis. Circular RNAs (circRNAs) are implicated in the pathomechanism of TNBC. Here, we investigated the function of circ_0000520 in TNBC and its associated mechanism.MethodsReverse transcription quantitative polymerase chain reaction (RT‐qPCR) and Western blot assay were used to measure RNA and protein expression. Cell proliferation was analyzed by cell counting kit‐8 (CCK8) assay, flow cytometry and colony formation assay. Cell apoptosis was assessed by flow cytometry. Cell migration ability was analyzed by transwell migration and wound healing assays. Transwell invasion assay was conducted to analyze the invasion ability. Dual‐luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA‐pulldown assay were performed to verify the interaction between microRNA‐1296 (miR‐1296) and circ_0000520 or zinc finger protein X‐linked (ZFX). Xenograft mice model was established to analyze the role of circ_0000520 in xenograft tumor growth in vivo.ResultsCirc_0000520 expression was upregulated in TNBC tissues and cell lines. Circ_0000520 knockdown suppressed the proliferation, migration, and invasion whereas induced the apoptosis of TNBC cells. miR‐1296 was verified as a target of circ_0000520, and circ_0000520 silencing‐mediated suppressive effects on the malignant potential of TNBC cells were partly overturned by miR‐1296 knockdown. miR‐1296 interacted with the 3′ untranslated region (3′UTR) of ZFX, and ZFX overexpression partly reversed miR‐1296 overexpression‐mediated effects in TNBC cells. Circ_0000520 absence reduced ZFX expression by upregulating miR‐1296 in TNBC cells. Circ_0000520 silencing suppressed xenograft tumor growth in vivo.ConclusionsCirc_0000520 contributed to TNBC development by binding to miR‐1296 to induce ZFX expression.

Circ_0020123 Increases ZFX Expression to Facilitate Non-Small Cell Lung Cancer Progression by Sponging miR-142-3p.

BackgroundCircular RNA (circRNA) is involved in the progression of various cancers and has been shown to be an important potential target for cancer therapy. Circ_0020123 has been found to act as oncogene to participate in the malignant progression of non-small cell lung cancer (NSCLC). Therefore, exploring new mechanisms of circ_0020123 regulating NSCLC progression will help us better understand its role in NSCLC.MethodsRelative expression levels of circ_0020123, microRNA (miR)-142-3p, and zinc-finger protein X-linked (ZFX) in tissues and cells were determined by quantitative real-time PCR (qRT-PCR). Cell proliferation, apoptosis, migration and invasion were assessed using cell counting kit 8 (CCK8) assay, colony formation assay, flow cytometry and transwell assay. Western blot (WB) analysis was used to detect relative protein level. Besides, the interaction between miR-142-3p and circ_0020123 or ZFX was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.ResultsOur results showed that circ_0020123 was upregulated in NSCLC, and its knockdown could suppress NSCLC cell proliferation, migration, invasion, and promote apoptosis. Circ_0020123 was found to interact with miR-142-3p. The inhibition effect of circ_0020123 silencing on NSCLC progression could be reversed by miR-142-3p inhibitor. ZFX could be targeted by miR-142-3p. The silencing of ZFX could hinder the progression of NSCLC and abolish the promotion effect of miR-142-3p inhibitor on NSCLC progression. In addition, circ_0020123 silencing inhibited NSCLC tumorigenesis by the miR-142-3p/ZFX axis.ConclusionThese findings suggested that circ_0020123 might be a potential therapy target for NSCLC, which could promote NSCLC progression through regulating the miR-142-3p/ZFX axis.

Long Noncoding RNA NEAT1 Promotes the Progression of Breast Cancer by Regulating miR-138-5p/ZFX Axis.

Background: Growing evidence demonstrated that long noncoding RNAs (lncRNAs) were involved in the progression of diverse cancers, including breast cancer (BC). Recent studies indicated that lncRNA nuclear enriched abundant transcript 1 (NEAT1) was overexpressed and facilitated tumor processes in many cancers. Nevertheless, the underlying mechanism of NEAT1 in regulating BC progression is still largely unknown. Materials and Methods: The abundance of NEAT1, microRNA-138-5p (miR-138-5p), and zinc finger protein X-linked (ZFX) was assessed by quantitative real-time polymerase chain reaction. Cell Counting Kit-8 (CCK-8) assay, flow cytometry, and transwell assay were utilized to evaluate cell proliferation, apoptosis, migration, and invasion, respectively. Western blot analysis was applied to detect the protein expression of CyclinD1, Bax, E-cadherin, and ZFX. The interaction between miR-138-5p and NEAT1 or ZFX was predicted by starBase v3.0 and validated by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation assays. The mice xenograft model was established to investigate the roles of NEAT1 in vivo. Results: NEAT1 was highly expressed and miR-138-5p was lowly expressed in BC tissues and cells. NEAT1 interference or miR-138-5p restoration repressed cell proliferation, migration, and invasion but accelerated apoptosis in BC cells. Moreover, miR-138-5p directly interacted with NEAT1 and its knockdown reversed the suppressive impact of NEAT1 downregulation on the progression of BC cells. In addition, ZFX was a downstream target of miR-138-5p and its upregulation attenuated the antitumor role of miR-138-5p in BC cells. Besides, ZFX expression was positively regulated by NEAT1 and inversely modulated by miR-138-5p. Furthermore, interference of NEAT1 inhibited tumor growth by upregulating miR-138-5p and downregulating ZFX. Conclusion: NEAT1 affected BC progression through modulating miR-138-5p/ZFX axis, providing a vital theoretical basis for BC treatment.

LncRNA SNHG20 contributes to cell proliferation and invasion by upregulating ZFX expression sponging miR-495-3p in gastric cancer.

Long noncoding RNAs (lncRNAs) exert key regulators in cancer development and progression. The functional significance of lncRNA small nucleolar RNA host gene 20 (SNHG20) was reported in gastric cancer (GC); however, the underlying molecular mechanism in GC development is largely unknown. Here, our results showed that the lncRNA SNHG20 expression was significantly higher in GC tissues compared with adjacent normal tissues by quantitative real-time PCR (qRT-PCR) analysis. Higher lncRNA SNHG20 expression was highly associated with tumor size and lymphatic metastasis of patients. Patients with higher lncRNA SNHG20 expression predicted a short disease-free survival (DFS) and overall survival (OS). Furthermore, lncRNA SNHG20 expression negatively associated with miR-495-3p expression and regulated miR-495-3p expression. Function assays confirmed that lncRNA SNHG20 knockdown using RNA interference suppressed cell proliferation and invasion of GC by negatively regulating miR-495-3p expression. Moreover, we demonstrated that lncRNA SNHG20 inhibited zinc finger protein X-linked (ZFX) expression by negatively miR-495-3p expression in GC cells. In vivo, the current study also indicated that lncRNA SNHG20 knockdown reduced the tumor growth by downregulating ZFX expression. Thus, our results implied that inhibition of SNHG20/miR-495-3p/ZFX axis may provide valuable target for GC treatment.

Zinc Finger Protein X-Linked Exhibits Pro-Leukemia Activity Via WNT3 in Chronic Myeloid Leukemia Stem/Progenitor Cells

Zinc Finger protein, X-linked (ZFX) is a transcriptional regulator, which controls the self-renewal of both embryonic and hematopoietic stem cells and participates in pathogenesis of various cancers. Zfx deficiency impairs Notch intracellular domain (NotchIC) induced acute T-cell leukemia (T-ALL) or MLL-AF9 induced acute myeloid leukemia (AML) in mice models. However, the function of ZFX in chronic myeloid leukemia (CML) stem/progenitor cells has not been elucidated yet.In the present study, qRT-PCR analysis showed that ZFX expression was significantly higher in CD34+ cells from CML patients in chronic phase (CP) (n=8, 3.1-fold, P=0.0052) and patients in blast crisis (BC) (n=8, 18.6-fold, P=0.0050) compared with that in healthy donors (n=4). Two independent shRNA sequences against ZFX were delivered in CD34+ cells with lentiviral vector. The silence of ZFX had a stronger inhibitory effect on colony-forming cell (CFC) ability of CML CD34+ cells (75±5%) than that of healthy donor CD34+ cells (44±5%). Furthermore, ZFX silencing augmented Imatinib Mesylate (IM) sensitivity of CML CD34+ cells, especially in IM-resistant samples; due to the fact that ZFX silencing increased apoptosis induced by IM. To obtain the molecular insights of how ZFX acts, we generated transcriptome data comparing ZFX silenced CML CD34+ cells with control cells. qRT-PCR data validated that ZFX silencing caused a significantly declined expression of WNT3 in K562, MEG-01 and CML CD34+ cells (n=5). In addition, ZFX silencing decreased WNT3 protein expression as well. Interestingly, WNT3 had significantly higher expression in CD34+ cells from patients in CP (n=10, 5-fold, P=0.0006) compared with that in healthy donors (n=8). Silence of WNT3 inhibited the growth of K562 cells and enhanced IM sensitivity of these cells as well. Overexpression of WNT3 restored the growth inhibition and IM hypersensitivity upon ZFX silencing. Chromatin immunoprecipitation (ChIP) analysis revealed that ZFX was able to bind with WNT3 promoter, and luciferase assay showed that ZFX silencing significantly decreased the activity of WNT3 promoter. Finally, we also found that the expressions of c-Myc and cyclin D1 were reduced by ZFX silencing or WNT3 silencing, suggesting decreased WNT/Catenin signaling.Taken together, we have demonstrated that ZFX is aberrantly expressed in CML stem/progenitor cells, and it modulates the growth and IM response of CML stem/progenitor cells via wnt/Catenin pathway indicating ZFX is a new regulator of CML stem/progenitor cells, which deepens the understanding of CML pathology and potentially provides clues for novel therapies against this disease. DisclosuresNo relevant conflicts of interest to declare.

MicroRNA-493 suppresses cell proliferation and invasion by targeting ZFX in human hepatocellular carcinoma.

MicroRNAs (miRNAs) are some RNA molecules that negatively regulate gene expression by binding to the 3'-untranslated region (3'-UTR) of target mRNA molecules. The aim of the study is to investigate the clinical role and functional effects of microRNA-493 (miR-493) in human hepatocellular carcinoma (HCC). Expression of miR-493 in 58 cases of HCC tissues and adjacent normal tissues was determined by using quantitative real-time PCR (qRT-PCR) analyses. In vitro, cell proliferation and invasion capacity was evaluated by CCK8 assay and trans-well invasion assay. Luciferase reporter assay, western blot and qRT-PCR were used to detect the association between miR-493 expression and zinc finger protein X-linked (ZFX) in HCC. Expression of miR-493 was significantly downregulated in HCC tissues compared to adjacent normal tissues. Lower miR-493 expression associated with tumor size, vascular invasion and poor overall survival (OS) and disease free survival (DFS) time of HCC patients. In vitro, transfection of miR-493 mimic in HCC cells inhibited cell proliferation and invasion abilities. However, transfection of miR-493 inhibitor in HCC cells had promoting effects. Luciferase reporter assay, qRT-PCR and western blot analysis demonstrated that miR-493 targeting 3'-untranslated region (3'-UTR) of ZFX and overexpression of miR-493 inhibited its expression. Moreover, enforced ZFX expression rescued the effects of miR-493 mimic on cell proliferation and invasion. MiR-493 functioned as tumor suppressor in HCC cells by regulating ZFX expression. Thus, miR-493 may provide potential value for HCC treatment.

Downregulation of ZFX is associated with inhibition of prostate cancer progression by baicalein

Background: Baicalein is a bioactive flavonoid that is widely used in China. However, its effects on prostate cancer (PCa) and relative mechanisms have not been extensively studied. We intended to study the potential anti-tumor effects of baicalein and the related mechanisms on PCa. Methods: We analyzed the inhibitory effects of baicalein on PCa by utilizing a cell viability assay and an in vivo tumor growth assay. Wound healing assay and transwell assay were performed to investigate cancer cell migration and invasion abilities. Then the expressions of zinc finger protein X-linked (ZFX) in PCa cells and xenograft tumor were respectively detected by western blot and immunohistochemistry assay. Results: Baicalein significantly inhibited cell proliferation in vitro and tumor growth of PCa in vivo. Consistently, baicalein induced significantly inhibition on the migration and invasion abilities of PCa cells. In addition, ZFX expressions were downregulated by baicalein in PCa both in vitro and in vivo. Conclusions: Our study provides evidence that baicalein plays important roles in PCa therapy probably by downregulating ZFX expression, which was demonstrated to be involved in PCa progression, and thus may be developed as a novel and efficient candidate agent for PCa therapy.

Zinc finger protein X-linked promotes expansion of EpCAM+ cancer stem-like cells in hepatocellular carcinoma.

Zinc finger protein X‐linked (ZFX) is frequently upregulated in multiple human malignancies and also plays a critical role in the maintenance of self‐renewal in embryonic stem cells. However, the role of ZFX in liver cancer stem cells (CSCs) remains obscure. We observed that the elevated expression of both ZFX and epithelial cell adhesion molecule (EpCAM) was associated with aggressive clinicopathological features and indicated poor prognosis in patients with hepatocellular carcinoma (HCC). ZFX was commonly enriched in liver EpCAM+ CSCs. Knockdown of ZFX decreased the proportion of EpCAM+ CSCs in HCC cells and suppressed their expression of stemness‐related genes, self‐renewal capacity, chemoresistance, metastatic potential, and tumorigenicity. Conversely, upregulation of ZFX in CSCs rescued these inhibitory effects and enhanced stem‐like properties. Mechanistically, depletion of ZFX reduced nuclear translocation and transactivation of β‐catenin, thereby inhibiting the self‐renewal capacity of EpCAM+ CSCs. Moreover, knockdown of β‐catenin attenuated the self‐renewal of EpCAM+ HCC cells stably expressing ZFX, further indicating that β‐catenin is required for ZFX‐mediated expansion and maintenance of EpCAM+ CSCs. Taken together, our findings indicate that ZFX activates and maintains EpCAM+ liver CSCs by promoting nuclear translocation and transactivation of β‐catenin. Furthermore, combination of ZFX and EpCAM may serve as a significant indicator for prognosis of patients with HCC.

Prognostic value of Zinc-finger protein X-linked in patients with solid tumors.

Many studies recently suggested that Zinc-finger protein X-linked (ZFX) acted as a novel oncoprotein in various malignancies. It was frequently overexpressed in cancerous tissues and the high expression of ZFX may have important clinical value. This meta-analysis aims to investigate the prognostic value of ZFX as a biomarker of solid cancers. We search for multiple databases, including Pubmed, Springer, Web of Science, CNKI from 1996 to Sep. 1, 2016. Eligible articles were collected to explore the association between the expression levels of ZFX and overall survival (OS). There were totally 933 cancer patients from eight studies. The pooled results indicated that cancer patients with high ZFX expression have shorter overall survival times (HR=2.26, 95%CI:1.77-2.75, P=0.000) than those with low ZFX expression. Statistical significance was also observed in subgroup meta-analysis stratified in the sampling object and cancer type. High expression of ZFX correlated with poor clinical outcome, ZFX might be sever as a potential prognostic biomarker in various cancers, especially for colorectal cancer.

ZFX Facilitates Cell Proliferation and Imatinib Resistance in Chronic Myeloid Leukemia Cells.

Zinc finger protein, X-linked (ZFX) mediates the development and progression of human cancers. However, its potential role in chronic myeloid leukemia (CML) is still unknown. The ZFX expression was significantly increased in CML patients and cell lines. Based on loss-of-function experiments in CML cells, we found that knockdown of ZFX expression impaired cell proliferation and induced mitotic arrest in G0/G1 stage and apoptosis. In addition, ZFX silencing sensitized CML cells to imatinib treatment. Further, phospho-Akt (p-Akt), CyclinD1, CyclinE1, and Bcl-2 were downregulated, and Caspase-3 was upregulated in ZFX-silenced cells. In summary, our data suggest that ZFX is a novel oncogene promoting cell proliferation and inducing imatinib resistance via PI3K/Akt signaling pathway. ZFX may represent a potential therapeutic target in CML.

High expression of Zinc-finger protein X-linked promotes tumor growth and predicts a poor outcome for stage II/III colorectal cancer patients.

Zinc-finger protein X-linked (ZFX) was recently identified as a novel oncoprotein in several human malignancies. In this study, we examined the correlation between ZFX expression and the clinical characteristics of stage II/III CRC patients, as well as the molecular mechanism by which ZFX apparently contributes to CRC tumor progression. Using immunohistochemistry, we detected expression of ZFX in CRC tissues collected from stage II/III patients and determined that its expression correlated with tumor differentiation and stage. Survival analysis indicated that patients with high ZFX expression had poorer overall and disease-free survival. ZFX knockdown in SW620 and SW480 CRC cells significantly inhibited cell proliferation and colony formation, enhanced apoptosis and induced cell cycle arrest. It also enhanced the sensitivity of CRC cells to 5-Fu. In a xenograft model, ZFX knockdown suppressed in vivo CRC tumor growth. Microarray analysis revealed the primary target of ZFX to be DUSP5. Whereas ZFX knockdown increased DUSP5 expression, DUSP5 knockdown rescued ZFX-mediated cell proliferation in ZFX knockdown cells. These findings demonstrate that ZFX promotes CRC progression by suppressing DUSP5 expression and suggest that ZFX is a novel prognostic biomarker and potentially useful therapeutic target in stage II/III CRC patients.

ZFX is a Strong Predictor of Poor Prognosis in Renal Cell Carcinoma.

BackgroundThis study was designed to assay the expression of zinc finger protein X-linked (ZFX) in renal cell carcinoma (RCC) tissues and evaluate the correlation between ZFX expression and prognosis of RCC patients.Material/MethodsThe expressions of ZFX mRNA in 53 RCC tissues and 51 normal tissues were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry (IHC) technology was used to measure the expression of ZFX protein. Then chi-square test was conducted to verify the association between ZFX expression and clinical parameters. Next, we explored the overall survival rate of RCC patients with Kaplan-Meier analysis. Finally, the correlation between ZFX expression and the prognosis of RCC patients was evaluated by Cox regression analysis.ResultsThe qRT-PCR result showed that the ZFX was significantly up-regulated in RCC tissues. As for the IHC consequence, the positive rate of ZFX expression in RCC specimens was 79.2%, while that in the normal control tissues was only 17.6%. Chi-square test showed that ZFX expression shared no close relationship with age, sex, or smoking (P>0.05), but was tightly associated with TNM stage, tumor size, and lymph node metastasis (P<0.05). Kaplan-Meier analysis showed that patients with ZFX positive expression had higher mortality than those with negative expression (P<0.05). Cox regression analysis revealed that ZFX expression had tight correlation with prognosis of RCC patients (HR=4.997, P=0.045, 95%CI=1.033–24.180).ConclusionsOur findings show that ZFX could be considered as a predictor for prognosis of RCC patients.

Zinc finger protein X-linked is overexpressed in colorectal cancer and is associated with poor prognosis

Zinc finger protein X-linked (ZFX) is a zinc finger transcription factor and plays a significant role in the self-renewal ability of embryonic stem cells and various cancers. However, its expression and function in colorectal cancer (CRC) remain unclear. In the present study, we evaluated the expression of ZFX in CRC using quantitative polymerase chain reaction (qPCR), western blot analysis and immunohistochemistry (IHC), and further explored its potential functions in CRC cell lines using cell counting kit-8 and Transwell invasion assays. qPCR and western blot analysis revealed that ZFX was significantly upregulated in CRC tissues; IHC further confirmed this finding, revealing that higher expression of ZFX was significantly associated with larger tumor size (P=0.01), higher pathological stage (P=0.02), depth of invasion (P=0.047), lymph node invasion (P=0.02) and higher American Joint Committee on Cancer (AJCC) stage (P=0.04). CRC patients with higher ZFX expression also exhibited significantly shorter survival times (P=0.019). Moreover, knockdown of ZFX significantly suppressed proliferation and invasion in CRC cell lines HCT116 and LoVo. These results suggest that ZFX plays a notable role in CRC tumorigenicity and may serve as a novel marker and therapeutic target for CRC.

Dysregulation of zinc finger protein, X-linked (ZFX) impairs cell proliferation and induces apoptosis in human oral squamous cell carcinorma.

Zinc finger protein, X-linked (ZFX) is a transcriptional factor involved in many physiological processes such as embryonic stem cell survival and self-renewal. Though ZFX dysfunctions have been identified in variant human diseases and especially in cancers, its pathological roles have not been fully addressed. Here, we explored the relationship between ZFX expression and squamous cell carcinoma (SCC) of the tongue. We found that ZFX expression was significantly higher in tongue SCC tumors as compared to tumor-adjacent normal tissues. Furthermore, ZFX knockdown impeded cell proliferation, impaired colony formation ability, and lead to cell cycle arrest while induced cell apoptosis in human tongue squamous cell carcinoma cell line Tca-8113. Our results provide evidence suggesting that ZFX overexpression is associated with the development of tongue SCC and ZFX knockdown is a potential treatment for tumor suppression.

Expression of ZFX gene correlated with the central features of the neoplastic phenotype in human brain tumors with distinct phenotypes.

Background:The zinc finger transcription factor zinc finger protein, X-linked (ZFX) acts as an important director of self-renewal in several stem cell types. Moreover, ZFX expression abnormally increases in various cancers and relates to tumor grade. We performed this study, to examine its role in the pathogenesis of astrocytoma and meningioma.Materials and Methods:We used real-time reverse transcription polymerase chain reaction method for evaluation of ZFX expression in 25 astrocytoma tumoral tissue and 25 meningioma tumoral tissues with different WHO grades. Furthermore, the association of gene expression with various clinic-pathological characteristics was examined.Results:We found that there is a significant association between gene expression and different tumor grades, the presence or absence of invasion, forming and nonforming of glomeruloid vessels, the age over or under 50 and the presence or absence of calcification in astrocytomas. This is the first report that shows that ZFX was directly correlated with the central features of the neoplastic phenotype, including the growth of cancer cells, angiogenesis, and invasion.Conclusion:Regarding all the above-mentioned studies, it is highly plausible that silencing the expression of ZFX gene in gliomas has a major role in the therapeutic interventions of the disease in future.

Overexpression of ZFX and its involvement in squamous cell carcinoma of the tongue.

Zinc finger protein, X-linked (ZFX) has been identified as a transcriptional factor and is implicated in the development of variant types of cancer. Furthermore, it has been reported that ZFX is essential for the survival and self-renewal of embryonic stem cells. To investigate the involvement of ZFX in squamous cell carcinoma of the tongue, in the present study, we explored the expression of ZFX in clinical specimens from patients with squamous cell carcinoma of the tongue and the correlation between ZFX expression and multiple clinical pathological parameters. We further evaluated the impact of ZFX knockdown on the proliferation, colony formation ability, cell cycle distribution and survival of two human tongue squamous cell carcinoma cell lines to explore its critical role in the development of squamous cell carcinoma of the tongue. Our results showed that ZFX expression was aberrantly higher in samples from patients with squamous cell carcinoma of the tongue and revealed that ZFX expression is positively correlated with tumor grade and stage. Consistent with these findings, we further found that ZFX knockdown impaired cell proliferation and colony formation ability and induced cell apoptosis and cell cycle arrest in two human tongue squamous cell carcinoma cell lines. Our results indicate that ZFX is essential for the development and progression of squamous cell carcinoma of the tongue and represents a potential target for the development of effective therapy.

Knockdown of ZFX suppresses renal carcinoma cell growth and induces apoptosis

The ZFX (zinc finger protein, X-linked) gene located on the human X chromosome controls the self-renewal of embryonic and hematopoietic stem cells as a transcriptional regulator. Recently, studies have affirmed that ZFX is associated with several human cancers, including lymphoma, laryngeal squamous cell carcinoma, prostate cancer, and liver cancer, which suggests ZFX as a potential therapeutic target in cancer. However, the functional role of ZFX in human renal cancer remains unclear. Herein, we detected the expression of ZFX in 42 patients with renal cancer and found the expression of ZFX was specifically upregulated in cancer tissues at the mRNA and protein levels. Moreover, we employed lentivirus-mediated short hairpin RNA (shRNA) to knock down ZFX expression in two human renal cell carcinoma cell lines, 786-0 and ACHN. Functional analysis indicated that ZFX silencing significantly inhibited renal cell carcinoma cell proliferation and cell cycle progression, probably because of suppression of CDK4 and cyclin D1, and induced apoptosis via activation of Bax, Caspase 3, and PUMA in a p53-dependent manner. Our findings suggest that knockdown of ZFX by shRNA may be a potential therapeutic approach for the treatment of renal cancer.

Overexpression of ZFX confers self-renewal and chemoresistance properties in hepatocellular carcinoma

Zinc finger protein X-linked (ZFX) is a zinc finger protein of Zfy family, which is highly conserved in vertebrates. This transcriptional regulator is not only highly expressed in embryonic stem cells (ESC) and hematopoietic stem cells, but is also upregulated in a number of human cancers where it is functional related to cell proliferation and survival. Hepatocellular carcinoma (HCC) is highly aggressive cancer that commonly resistant to most chemotherapies and displays stemness characteristics. In this study, we examined the expression of ZFX in HCC and its possible functional implications in liver tumorigenesis. Quantitative RT-PCR analysis showed common overexpressions of ZFX in 51.8% HCC tumors when compared with their adjacent nonmalignant liver (n = 43/83; p = 0.004). Inline with the pluripotency role of ZFX, we found silencing of ZFX readily inhibited self-renewal capability (p = 0.0022), colony formation ability (p < 0.0001) and cell proliferation (p < 0.0001) through G0/G1 cell cycle arrest of HCC cells (p = 0.0038). In addition, suppression of ZFX sensitized HCC cells to chemotherapeutic agent cisplatin (p < 0.0001). Further investigations suggested that ZFX bind on the promoter of two important mediators, namely Nanog and SOX-2, activating their expressions in HCC (p < 0.0001). Moreover, in vivo xenograft study demonstrated that overexpression of ZFX would promote the tumor growth (p = 0.031). Taken together, our results show, for the first time, commonly overexpressions of ZFX in HCC, where it likely contributes to the stemness and pluripotent behavior of this highly malignant cancer.

ShRNA-mediated silencing of ZFX attenuated the proliferation of breast cancer cells

Breast cancer is the cause for highest number of cancer-related death among women worldwide. This study was focused on investigating the role of zinc-finger protein X-linked (ZFX) in human breast cancer. Expression levels of ZFX were analyzed in 99 patients and four breast cancer cell lines. Lentivirus-mediated RNA interference was applied to silence ZFX expression, and the effects of ZFX knockdown on the growth of breast cancer cells were investigated. The immunohistochemical expression of ZFX was higher in more advanced tumor tissues. ZFX was also overexpressed in multiple breast cancer cell lines. Knockdown of ZFX inhibited cell proliferation and colony formation of MCF-7 and MDA-MB-231 cells. Moreover, ZFX silencing resulted in cell cycle arrest at G0/G1 phase. Depletion of ZFX decreased the phosphorylation level of AKT and increased the phosphorylation level of ERK2 and the expression of cyclin D1, which is involved in cell survival and cell cycle regulation. These findings suggest that ZFX plays an important role in breast cancer development and could be a potential therapeutic target for breast cancer.

Knockdown of ZFX inhibits gastric cancer cell growth in vitro and in vivo via downregulating the ERK-MAPK pathway

Zinc finger protein X-linked (ZFX) is a zinc finger transcription factor encoded on the X chromosome. Here, we found that ZFX expression was significantly upregulated in gastric cancer (GC) cell lines and tissues. Knockdown of ZFX induced significant apoptosis and cell cycle arrest in SGC7901 and MGC803 cells. Moreover, we demonstrated for the first time that knockdown of ZFX inhibited gastric cancer cell growth in vitro and in vivo via downregulating the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK-MAPK) pathway. Therefore, ZFX play a prominent role in GC tumorigenicity and may have potential applications in the diagnosis or treatment of GC.