The zinc finger transcription factor ZKSCAN3 promotes prostate cancer cell migration

Targeting ONECUT2 inhibits tumor angiogenesis via down-regulating ZKSCAN3/VEGFA

OC-2 plays a vital role in tumor growth, metastasis and angiogenesis, but molecular mechanism how OC-2 regulates angiogenic factors is unclear. We found that OC-2 was highly expressed in HepG2, COLO, MCF-7, SKOV3 cells and rectum carcinoma tissues, and angiogenic factors levels were positively related to OC-2. Then OC-2 KD inhibited the tumor growth, metastasis and angiogenesis process in vitro and vivo. ChIP-Seq showed that 228 target genes of OC-2 were identified and they were associated with tumor growth, metastasis, angiogenesis and signal transduction; OC-2 bound to ZKSCAN3 at promoter region. Luciferase assays showed that ZKSCAN3 was identified as target gene of OC-2 and VEGFA was identified as target gene of ZKSCAN3; OC-2 promoted VEGFA expression via activating ZKSCAN3 transcriptional program. Importantly, OC-2 KD down-regulated VEGFA secretion to suppress tumor angiogenesis of HUVECs. Besides VEGFA, OC-2 was positively correlated with other angiogenic factors HIF-1α, FGF2, EGFL6 and HGF. Meanwhile, ERK1/2 and Smad1 signaling pathways might be related to function of OC-2 driving tumor aggressiveness. We revealed that OC-2 might regulate tumor growth, metastasis, angiogenesis via ERK1/2, Smad1 signaling pathways and regulate VEGFA expression for tumor angiogenesis via activating ZKSCAN3 transcriptional program, indicating that OC-2 was a convincing target to develop novel anti-tumor drugs based on angiogenesis.

Expression of ZKSCAN3 protein suppresses proliferation, migration, and invasion of pancreatic cancer through autophagy

Elevated autophagy activity enhances the malignancy of pancreatic cancer (PaCa), and autophagy is recognized as a novel therapeutic target. Zinc finger protein with KRAB and SCAN domains 3 (ZKSCAN3) is a transcription factor that suppresses autophagy, but its association with PaCa is unknown. We analyzed the function of ZKSCAN3 in PaCa and investigated whether autophagy regulation through ZKSCAN3 could become a new therapeutic target for PaCa. Using reverse transcription-quantitative polymerase chain reaction and western blotting, we observed that ZKSCAN3 expression was upregulated in several PaCa cell lines compared with normal pancreatic ductal epithelial cells. Additionally, comparing ZKSCAN3 expression with the prognosis of PaCa patients using web databases, we found that higher ZKSCAN3 expression in PaCa was associated with extended overall survival. Knocking down ZKSCAN3 promoted the proliferation of PaCa cells. Moreover, following ZKSCAN3 knockdown, PaCa cells exhibited significantly enhanced migratory and invasive properties. Conversely, overexpression of ZKSCAN3 significantly suppressed the proliferation, migration and invasion of PaCa cells. Additionally, the knockdown of ZKSCAN3 increased the expression of LC3-II, a marker of autophagy, whereas ZKSCAN3 overexpression decreased LC3-II expression. In a xenograft mouse model, tumors formed by MIA PaCa-2 cells in which ZKSCAN3 was knocked down significantly increased in size compared with the control group. In conclusion, ZKSCAN3 expression was upregulated in several pancreatic cancer cells. Additionally, it was revealed that ZKSCAN3 is negatively correlated with the malignancy of PaCa through autophagy. These results suggest that autophagy regulation via ZKSCAN3 may be a new therapeutic target for PaCa.

Association Between Diverse Cell Death Patterns Related Gene Signature and Prognosis, Drug Sensitivity, and Immune Microenvironment in Glioblastoma

Glioblastoma (GBM) is the most invasive type of glioma and is difficult to treat. Diverse programmed cell death (PCD) patterns have a significant association with tumor initiation and progression. A novel prognostic model based on PCD genes may serve as an effective tool to predict the prognosis of GBM. The study incorporated 11 PCD patterns, namely apoptosis, necroptosis, pyroptosis, ferroptosis, cuproptosis, entotic cell death, netotic cell death, parthanatos, lysosome-dependent cell death, autophagy-dependent cell death, alkaliptosis, and oxeiptosis, to develop the model. To construct and validate the model, both bulk and single-cell transcriptome data, along with corresponding clinical data from GBM cases, were obtained from the TCGA-GBM, REMBRANDT, CGGA, and GSE162631 datasets. A cell death-related signature containing 14 genes was constructed with the TCGA-GBM cohort and validated in the REMBRANDT and CGGA datasets. GBM patients with a higher cell death index (CDI) were significantly associated with poorer survival outcomes. Two separate clusters associated with clinical outcomes emerged from unsupervised analysis. A multivariate Cox regression analysis was conducted to examine the association of CDI with clinical characteristics, and a prognostic nomogram was developed. Drug sensitivity analysis revealed high-CDI GBM patients might be resistant to carmustine while sensitive to 5-fluorouracil. Less abundance of natural killer cells was found in GBM cases with high CDI and bulk transcriptome data. A cell death-related prognostic model that could predict the prognosis of GBM patients with good performance was established, which could discriminate between the prognosis and drug sensitivity of GBM.

Effect of Lacking ZKSCAN3 on Autophagy, Lysosomal Biogenesis and Senescence

Transcription factors can affect autophagy activity by promoting or inhibiting the expression of autophagic and lysosomal genes. As a member of the zinc finger family DNA-binding proteins, ZKSCAN3 has been reported to function as a transcriptional repressor of autophagy, silencing of which can induce autophagy and promote lysosomal biogenesis in cancer cells. However, studies in Zkscan3 knockout mice showed that the deficiency of ZKSCAN3 did not induce autophagy or increase lysosomal biogenesis. In order to further explore the role of ZKSCAN3 in the transcriptional regulation of autophagic genes in human cancer and non-cancer cells, we generated ZKSCAN3 knockout HK-2 (non-cancer) and Hela (cancer) cells via the CRISPR/Cas9 system and analyzed the differences in gene expression between ZKSCAN3 deleted cells and non-deleted cells through fluorescence quantitative PCR, western blot and transcriptome sequencing, with special attention to the differences in expression of autophagic and lysosomal genes. We found that ZKSCAN3 may be a cancer-related gene involved in cancer progression, but not an essential transcriptional repressor of autophagic or lysosomal genes, as the lacking of ZKSCAN3 cannot significantly promote the expression of autophagic and lysosomal genes.

Role of the WNT/β-catenin/ZKSCAN3 Pathway in Regulating Chromosomal Instability in Colon Cancer Cell lines and Tissues

Zinc finger protein with KRAB and SCAN domains 3 (ZKSCAN3) acts as an oncogenic transcription factor in human malignant tumors, including colon and prostate cancer. However, most of the ZKSCAN3-induced carcinogenic mechanisms remain unknown. In this study, we identified ZKSCAN3 as a downstream effector of the oncogenic Wnt/β-catenin signaling pathway, using RNA sequencing and ChIP analyses. Activation of the Wnt pathway by recombinant Wnt gene family proteins or the GSK inhibitor, CHIR 99021 upregulated ZKSCAN3 expression in a β-catenin-dependent manner. Furthermore, ZKSCAN3 upregulation suppressed the expression of the mitotic spindle checkpoint protein, Mitotic Arrest Deficient 2 Like 2 (MAD2L2) by inhibiting its promoter activity and eventually inducing chromosomal instability in colon cancer cells. Conversely, deletion or knockdown of ZKSCAN3 increased MAD2L2 expression and delayed cell cycle progression. In addition, ZKSCAN3 upregulation by oncogenic WNT/β-catenin signaling is an early event of the adenoma–carcinoma sequence in colon cancer development. Specifically, immunohistochemical studies (IHC) were performed using normal (NM), hyperplastic polyps (HPP), adenomas (AD), and adenocarcinomas (AC). Their IHC scores were considerably different (61.4 in NM; 88.4 in HPP; 189.6 in AD; 246.9 in AC). In conclusion, ZKSCAN3 could be responsible for WNT/β-catenin-induced chromosomal instability in colon cancer cells through the suppression of MAD2L2 expression.

The kidney-expressed transcription factor ZKSCAN3 is dispensable for autophagy transcriptional regulation and AKI progression in mouse

Acute kidney injury (AKI) is a common clinical disease that can cause serious harm to the kidneys, but it has no effective treatment till now. The modulation of autophagy pathway regulation is considered a potentially effective therapeutic approach in AKI prevention and treatment. ZKSCAN3 has been shown to be an important transcription factor that negatively regulates autophagy activity in cancer tissues. In order to determine whether autophagy could be activated by knocking out ZKSCAN3 to exert the renal protective effect of autophagy, we constructed AKI models with Zkscan3 knockout (KO) mice and detected renal pathological changes and renal function changes as well as autophagy-related indicators. We found that Zkscan3 KO had no significant effect on kidney development. Besides, no significant changes in autophagy activity were observed under normal physiological or AKI conditions. In non-tumor tissues, ZKSCAN3 did not mediate transcriptional regulation of autophagy-related genes. These findings suggest that because ZKSCAN3 may not function in the transcriptional regulation of autophagy-related genes in non-tumor tissues, it may not be used as a therapeutic target for AKI.

Context-dependent pro- and anti-resection roles of ZKSCAN3 in the regulation of fork processing during replication stress

Uncontrolled resection of replication forks under stress can cause genomic instability and influence cancer formation. Extensive fork resection has also been implicated in the chemosensitivity of “BReast CAncer gene” BRCA-deficient cancers. However, how fork resection is controlled in different genetic contexts and how it affects chromosomal stability and cell survival remains incompletely understood. Here, we report a novel function of the transcription repressor ZKSCAN3 in fork protection and chromosomal stability maintenance under replication stress. We show disruption of ZKSCAN3 function causes excessive resection of replication forks by the exonuclease Exo1 and homologous DNA recombination/repair protein Mre11 following fork reversal. Interestingly, in BRCA1-deficient cells, we found ZKSCAN3 actually promotes fork resection upon replication stress. We demonstrate these anti- and pro-resection roles of ZKSCAN3, consisting of a SCAN box, Kruppel-associated box, and zinc finger domain, are mediated by its SCAN box domain and do not require the Kruppel-associated box or zinc finger domains, suggesting that the transcriptional function of ZKSCAN3 is not involved. Furthermore, despite the severe impact on fork structure and chromosomal stability, depletion of ZKSCAN3 did not affect the short-term survival of BRCA1-proficient or BRCA1-deficient cells after treatment with cancer drugs hydroxyurea, PARPi, or cisplatin. Our findings reveal a unique relationship between ZKSCAN3 and BRCA1 in fork protection and add to our understanding of the relationships between replication fork protection, chromosomal instability, and chemosensitivity.

ZKSCAN5 Activates VEGFC Expression by Recruiting SETD7 to Promote the Lymphangiogenesis, Tumour Growth, and Metastasis of Breast Cancer

The growth of lymphatic vessels (lymphangiogenesis) plays a pivotal role in breast cancer progression and metastasis and the immune response. Vascular endothelial growth factor C (VEGFC) has been demonstrated to accelerate cancer metastasis and modulate the immune system by enhancing lymphangiogenesis. However, it remains largely unclear how transcription factors physically regulate VEGFC expression by interacting with histone-modifying enzymes. Like many histone-modifying enzymes, SETD7 plays a key role in cell proliferation and inhibits tumour cell differentiation. In this study, we identified the role of the transcription factor zinc finger with KRAB and SCAN domains 5 (ZKSCAN5) in interacting with histone methyltransferase SETD7 and mediating VEGFC transcription and tumour lymphangiogenesis. ZKSCAN5 interacts with and recruits SETD7 to the VEGFC promoter. By regulating breast cancer-secreted VEGFC, ZKSCAN5 could induce the tube formation of lymph endothelial cells, which promotes tumour proliferation, migration, and metastasis. Clinically, the expression of ZKSCAN5 was frequently upregulated in patients with breast cancer and positively correlated with the expression of VEGFC and the number of lymphatic microvessels. ZKSCAN5 is a poor prognostic factor for patients with breast cancer. Our results characterise the role of ZKSCAN5 in regulating VEGFC transcription and predict ZKSCAN5 as a breast cancer therapeutic target.

Deacetylation of ZKSCAN3 by SIRT1 induces autophagy and protects SN4741 cells against MPP+-induced oxidative stress

Mitochondrial dysfunction, oxidative stress and misfolded protein aggregation are related to autophagy-lysosomal dysregulation and contribute to the pathogenesis of Parkinson' s disease (PD). ZKSCAN3, a transcriptional repressor, plays a crucial role in autophagy and lysosomal biogenesis. However, the role and modification of ZKSCAN3 in the defection of ALP, along with the molecular mechanism involved in pathogenesis of PD, still remain unclear. In this study, we demonstrated that cellular reactive oxygen species (ROS) generated by MPP⁺ exposure and the resulting oxidative damage were counteracted by SIRT1-ZKSCAN3 pathway induction. Here we showed that nuclear ZKSCAN3 significantly increased in ventral midbrain of MPTP-treated mice and MPP⁺-treated SN4741 cells. Knockdown of ZKSCAN3 alleviated MPP⁺-induced ALP defect, Tyrosine Hydroxylase (TH) declination and neuronal death. NAC, a ROS scavenger, reduced the nuclear translocation of ZKSCAN3 and sequentially improved ALP function in MPP⁺-treated SN4741 cells. SRT2104, a SIRT1 activator, attenuated impairment of ALP in MPP⁺-treated SN47417 cells through decreasing nuclear accumulation of ZKSCAN3 and protected dopaminergic neurons from MPTP injury. Moreover, SRT2104 relieved impairment in locomotor activities and coordination skills upon treatment of MPTP in C57/BL6J mice through behavior tests including rotarod, pole climbing and grid. Furthermore, ZKSCAN3 was a novel substrate of SIRT1 which was deacetylated at lysine 148 residues by SIRT1. This subsequently facilitated the shuttling of ZKSCAN3 to the cytoplasm. Therefore, our study identifies a novel acetylation-dependent regulatory mechanism of nuclear translocation of ZKSCAN3. It results in autophagy-lysosomal dysfunction and then leads to DA neuronal death in MPTP/MPP⁺ model of PD.

ZNF655 Promotes the Progression of Glioma Through Transcriptional Regulation of AURKA

Objectives

Glioma has a high degree of malignancy, strong invasiveness, and poor prognosis, which is always a serious threat to human health. Previous studies have reported that C2H2 zinc finger (ZNF) protein is involved in the progression of various cancers. In this study, the clinical significance, biological behavior, and molecule mechanism of ZNF655 in glioma were explored.

Methods

The expression of ZNF655 in glioma and its correlation with prognosis were analyzed through public datasets and immunohistochemical (IHC) staining. The shRNA-mediated ZNF655 knockdown was used to explore the effects of ZNF655 alteration on the phenotypes and tumorigenesis of human glioma cell lines. Chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter assays were performed to determine the potential mechanism of ZNF655 regulating Aurora kinase A (AURKA).

Results

ZNF655 was abundantly expressed in glioma tissue and cell lines SHG-44 and U251. Knockdown of suppressed the progression of glioma cells, which was characterized by reduced proliferation, enhanced apoptosis, cycle repression in G2, inhibition of migration, and weakened tumorigenesis. Mechanistically, transcription factor ZNF655 activated the expression of AURKA by directly binding to the promoter of AURKA. In addition, downregulation of AURKA partially reversed the promoting effects of overexpression of ZNF655 on glioma cells.

Conclusions

ZNF655 promoted the progression of glioma by binding to the promoter of AURKA, which may be a promising target for molecular therapy.

Zkscan3 affects erythroblast development by regulating the transcriptional activity of GATA1 and KLF1 in mice

ZKSCAN3 encodes a zinc-finger transcription factor that regulates the expression of important genes and plays a significant role in tumor development, pathogenesis, and metastasis. However, its biological functions under normal physiological conditions remain largely unknown. In our previous studies, using flow cytometry, we found that the deletion of Zkscan3 may cause abnormal erythropoiesis. In this study, we found that, in a Zkscan3 knockout mice model, the number of splenic early-stage (basophilic-erythroblasts) and late-stage (chromatophilic-erythroblasts to polychromatophilic-erythroblasts through orthochromatophilic-erythroblasts) erythroblasts increased, whereas the number of late erythroblasts in the bone marrow decreased. Moreover, the phenotype was exacerbated after treating mice with phenylhydrazine (PHZ), which causes severe hemolytic anemia. In the knockout mice treated with PHZ, the percentage of reticulocyte in the peripheral blood conspicuously increased, whereas MCHC and red blood cells decreased. Then, we performed RNA-seq and quantitative-polymerase chain reaction assay and found that the expression of GATA1 and Tiam1 in erythroblasts were upregulated, whereas KLF1 was downregulated. Luciferase assays showed that Zkscan3 inhibited the transcription of GATA1 and Tiam1 and promoted the expression of KLF1. Additionally, ChIP and CO-IP results confirmed that Zkscan3 directly interacts with GATA1 and inhibits its transcriptional activity in MEL cells. Our results demonstrate, for the first time, the significant role of Zkscan3 in physiological erythropoiesis through the interaction with GATA1, both at the DNA and protein level, and with Tiam1 and KLF1 at the DNA level.

ZKSCAN3 in severe bacterial lung infection and sepsis-induced immunosuppression

The mortality rates among patients who initially survive sepsis are, in part, associated with a high risk of secondary lung infections and respiratory failure. Given that phagolysosomes are important for intracellular killing of pathogenic microbes, we investigated how severe lung infections associated with post-sepsis immunosuppression affect phagolysosome biogenesis. In mice with P. aeruginosa-induced pneumonia, we found a depletion of both phagosomes and lysosomes, as evidenced by decreased amounts of microtubule associated protein light chain 3-II (LC3-II) and lysosomal-associated membrane protein (LAMP1). We also found a loss of transcription factor E3 (TFE3) and transcription factor EB (TFEB), which are important activators for transcription of genes encoding autophagy and lysosomal proteins. These events were associated with increased expression of ZKSCAN3, a repressor for transcription of genes encoding autophagy and lysosomal proteins. Zkscan3-/- mice had increased expression of genes involved in the autophagy-lysosomal pathway along with enhanced killing of P. aeruginosa in the lungs, as compared to wild-type mice. These findings highlight the involvement of ZKSCAN3 in response to severe lung infection, including susceptibility to secondary bacterial infections due to immunosuppression.

KRAB-ZFP Transcriptional Regulators Acting as Oncogenes and Tumor Suppressors: An Overview

Krüppel-associated box zinc finger proteins (KRAB-ZFPs) constitute the largest family of transcriptional factors exerting co-repressor functions in mammalian cells. In general, KRAB-ZFPs have a dual structure. They may bind to specific DNA sequences via zinc finger motifs and recruit a repressive complex through the KRAB domain. Such a complex mediates histone deacetylation, trimethylation of histone 3 at lysine 9 (H3K9me3), and subsequent heterochromatization. Nevertheless, apart from their repressive role, KRAB-ZFPs may also co-activate gene transcription, likely through interaction with other factors implicated in transcriptional control. KRAB-ZFPs play essential roles in various biological processes, including development, imprinting, retroelement silencing, and carcinogenesis. Cancer cells possess multiple genomic, epigenomic, and transcriptomic aberrations. A growing number of data indicates that the expression of many KRAB-ZFPs is altered in several tumor types, in which they may act as oncogenes or tumor suppressors. Hereby, we review the available literature describing the oncogenic and suppressive roles of various KRAB-ZFPs in cancer. We focused on their association with the clinicopathological features and treatment response, as well as their influence on the cancer cell phenotype. Moreover, we summarized the identified upstream and downstream molecular mechanisms that may govern the functioning of KRAB-ZFPs in a cancer setting.

Impact of Vasectomy on the Development and Progression of Prostate Cancer: Preclinical Evidence

Some observational studies have implied a link between vasectomy and an elevated risk of prostate cancer. We investigated the impact of vasectomy on prostate cancer outgrowth, mainly using preclinical models. Neoplastic changes in the prostate were compared in transgenic TRAMP mice that underwent vasectomy vs. sham surgery performed at 4 weeks of age. One of the molecules identified by DNA microarray (i.e., ZKSCAN3) was then assessed in radical prostatectomy specimens and human prostate cancer lines. At 24 weeks, gross tumor (p = 0.089) and poorly differentiated adenocarcinoma (p = 0.036) occurred more often in vasectomized mice. Vasectomy significantly induced ZKSCAN3 expression in prostate tissues from C57BL/6 mice and prostate cancers from TRAMP mice. Immunohistochemistry showed increased ZKSCAN3 expression in adenocarcinoma vs. prostatic intraepithelial neoplasia (PIN), PIN vs. non-neoplastic prostate, Grade Group ≥3 vs. ≤2 tumors, pT3 vs. pT2 tumors, pN1 vs. pN0 tumors, and prostate cancer from patients with a history of vasectomy. Additionally, strong (2+/3+) ZKSCAN3 expression (p = 0.002), as an independent prognosticator, or vasectomy (p = 0.072) was associated with the risk of tumor recurrence. In prostate cancer lines, ZKSCAN3 silencing resulted in significant decreases in cell proliferation/migration/invasion. These findings suggest that there might be an association between vasectomy and the development and progression of prostate cancer, with up-regulation of ZKSCAN3 expression as a potential underlying mechanism.

ZKSCAN3 counteracts cellular senescence by stabilizing heterochromatin

Zinc finger protein with KRAB and SCAN domains 3 (ZKSCAN3) has long been known as a master transcriptional repressor of autophagy. Here, we identify a novel role for ZKSCAN3 in alleviating senescence that is independent of its autophagy-related activity. Downregulation of ZKSCAN3 is observed in aged human mesenchymal stem cells (hMSCs) and depletion of ZKSCAN3 accelerates senescence of these cells. Mechanistically, ZKSCAN3 maintains heterochromatin stability via interaction with heterochromatin-associated proteins and nuclear lamina proteins. Further study shows that ZKSCAN3 deficiency results in the detachment of genomic lamina-associated domains (LADs) from the nuclear lamina, loss of heterochromatin, a more accessible chromatin status and consequently, aberrant transcription of repetitive sequences. Overexpression of ZKSCAN3 not only rescues premature senescence phenotypes in ZKSCAN3-deficient hMSCs but also rejuvenates physiologically and pathologically senescent hMSCs. Together, these data reveal for the first time that ZKSCAN3 functions as an epigenetic modulator to maintain heterochromatin organization and thereby attenuate cellular senescence. Our findings establish a new functional link among ZKSCAN3, epigenetic regulation, and stem cell aging.

ZKSCAN3 drives tumor metastasis via integrin β4/FAK/AKT mediated epithelial-mesenchymal transition in hepatocellular carcinoma

Background

ZKSCAN3, a zinc-finger transcription factor containing KRAB and SCAN domains, has been reported to be regulated in several human cancers. However, its expression and function in hepatocellular carcinoma (HCC) remains unknown.

Methods

Expression of ZKSCAN3 in HCC was analyzed by western blotting, immunohistochemistry, and real time PCR. Its correlation with the clinicopathological characteristics and prognosis of HCC patients was analyzed. The effects of ZKSCAN3 on the migration and invasion were determined by Transwell assays. The potential downstream targets of ZKSCAN3 and related molecular mechanisms were clarified by Western blot and dual luciferase reporter assay.

Results

In this study, we demonstrated for the first time that ZKSCAN3 mRNA and protein was up-regulated in HCC tissues and cell lines. High ZKSCAN3 expression was significantly associated with poor prognostic features, including advanced TNM stage and vascular invasion. For 5-year survival, ZKSCAN3 served as a potential prognostic marker of HCC patients. Functionally, ZKSCAN3 promoted migration, invasion and EMT progress via directly binding to integrin β4 (ITGB4) promoter and enhanced its expression. Further investigation proved that ITGB4 triggers the focal adhesion kinase (FAK) to activate the AKT signaling pathway. Inactivation of FAK and AKT by their specific inhibitors respectively reversed the effects of ZKSCAN3 on HCC cells. In addition, we demonstrated that ZKSCAN3 expression was regulated by miR-124. In HCC tissues. MiR-124 has an inverse correlation with ZKSCAN3 expression.

Conclusion

We demonstrate for the first time that ZKSCAN3 is overexpressed in HCC tissues and promotes migration, invasion and EMT process through ITGB4-dependent FAK/AKT activation, which was regulated by miR-124, suggesting the potential therapeutic value for HCC.

Zkscan3 gene is a potential negative regulator of plasma cell differentiation

We previously showed that the ZKSCAN3 gene codes for a zinc-finger transcription factor that regulates the expression of important genes and plays crucial roles in the development, metastasis, and pathogenesis of rectal cancer, prostate cancer, myeloma, and so on, and in the regulation of autophagy. However, its biological functions under normal physiological conditions remain unclear. In addition, our previous studies showed that the ZKSCAN3 gene may negatively regulate B cell functions. Therefore, we constructed a zkscan3-knockout mouse model and observed that knockout mice contained a greater number of plasma cells than wild-type mice. We also found that the number of plasma cells was significantly increased in either colorectal cancer xenografts or under lipopolysaccharide-induced conditions. RNA-seq and quantitative-polymerase chain reaction assay indicated that the X-inactive-specific transcript is upregulated in B cells of zkscan3-knockout mice, which may represent a potential mechanism how zkscan3 modulates plasma cell differentiation.

Role of the zinc finger and SCAN domain-containing transcription factors in cancer

Transcription factors are key determinants of gene expression that recognize and bind to short DNA sequence motifs, thereby regulating many biological processes including differentiation, development, and metabolism. Transcription factors are increasingly recognized for their roles in cancer progression. Here, we describe a subfamily of zinc finger transcription factors named zinc finger and SCAN domain containing (ZSCAN) transcription factors. In this review, we summarize the identified members of the ZSCAN family of transcription factors and their roles in cancer progression. Due to the complex regulation mechanisms, ZSCAN transcription factors may show promotive or prohibitive efforts in angiogenesis, cell apoptosis, cell differentiation, cell migration and invasion, cell proliferation, stem cell properties, and chemotherapy sensitivity. The upstream regulation mechanisms of their varied expression levels may include gene mutation, DNA methylation, alternative splicing, and miRNA regulation. What's more, to clarify their diverse functions, we summarize the modulation mechanisms of their activity in downstream genes transcription, including protein-protein interactions mediated by their SCAN box, recruitment of co-regulating molecules and post-translational modifications. A better understanding of the widespread regulatory mode of these transcription factors will provide further insight into the mechanism of transcriptional regulation and suggest novel therapeutic strategies against tumor progression.

A30P mutant α-synuclein impairs autophagic flux by inactivating JNK signaling to enhance ZKSCAN3 activity in midbrain dopaminergic neurons

Mutations in α-synuclein gene have been linked to familial early-onset Parkinson's disease (PD) with Lewy body pathology. A30P mutant α-synuclein is believed to suppress autophagic progression associated with PD pathogenesis. However, the mechanistic link between A30P mutation and autophagy inhibition in PD remains poorly understood. In this study, we identified that A30P mutant α-synuclein resulted in reduced autophagy flux through promoting the decrease of autophagosomal membrane-associated protein LC3 and the increase of SQSTM1/p62 protein levels in midbrain dopaminergic neuron, due to the transcriptional repressor ZKSCAN3 trafficking from the cytoplasm to the nucleus. Moreover, the results demonstrated that A30P mutant α-synuclein not only decreased the phospho-c-Jun N-terminal Kinase (p-JNK) levels in midbrain dopaminergic neuron but also interfered autophagy without influencing the activities of AMPK and mTOR. Collectively, the present study reveals a novel autophagy inhibition mechanism induced by A30P mutant α-synuclein via transcriptional activation of the ZKSCAN3 in a JNK-dependent manner.

ZKSCAN3 Upregulation and Its Poor Clinical Outcome in Uterine Cervical Cancer

Zinc finger with KRAB and SCAN domain 3 (ZKSCAN3) upregulates genes encoding proteins involved in cell differentiation, proliferation and apoptosis. ZKSCAN3 has been reported to be overexpressed in several human cancers such as colorectal cancer and prostate cancer and is proposed as a candidate oncoprotein. However, the molecular mechanism by which ZKSCAN3 participates in carcinogenesis is largely unknown. Here, we evaluated ZKSCAN3 expression in uterine cervical cancers (CC) by immunohistochemistry using formalin-fixed, paraffin-embedded tissues from 126 biopsy samples from 126 patients. The clinicopathological findings were analyzed and compared with ZKSCAN3 expression levels. ZKSCAN3 was strongly overexpressed in CCs compared to adjacent non-neoplastic cervical mucosa tissues. Moreover, a gene copy number assay showed amplified ZKSCAN3 in CC samples. ZKSCAN3 overexpression was also significantly associated with poor overall survival of the patients. Overall, our findings indicate that ZKSCAN3 overexpression is a frequent event in uterine CC and is correlated with a poor clinical outcome. ZKSCAN3 could be developed as a molecular marker for prognostic prediction and early detection.

ZKSCAN3 promotes breast cancer cell proliferation, migration and invasion

ZKSCAN3, a zinc-finger transcription factor, which has been shown to be upregulated in several human cancer. However, the expression level, function and mechanism of ZKSCAN3 in breast cancer remains unknown. In the current study, immunohistochemistry, western blot and quantitative real time polymerase chain reaction (qRT-PCR) results showed that ZKSCAN3 was overexpressed in breast cancer tissue compared with normal breast tissue. Through analyzing the clinicopathological characteristics, we demonstrated that positive ZKSCAN3 expression predicted poor prognosis of patients with breast cancer. The expression level of ZKSCAN3 protein/mRNA in breast cancer cells (MCF-7 and MDA-MB-231) was higher than its expression in normal breast cells (HBL-100). Knocking down ZKSCAN3 via its short hairpin RNA (shRNA) in MCF-7 and MDA-MB-231 inhibited cell viability, migration and invasion. Western blot analysis showed that ZKSCAN3 silencing lead to significant decreases in the expression of Cyclin D1, B-cell lymphoma-2 (Bcl-2), and matrix metalloproteinase (MMP)-2/MMP-9, as well as increases in the expression of Bcl2 Associated X Protein (Bax) in breast cancer cells. Additionally, ZKSCAN3-shRNA expression markedly suppressed tumor growth in breast cancer xenograft mice. Finally, we demonstrated that silencing of ZKSCAN3 was able to inhibit Akt/mTOR signaling pathway by blocking p-Akt and p-mTOR protein expression in breast cancer cells. These results demonstrate that ZKSCAN3 plays a significant role in the progression of breast cancer. Therefore, ZKSCAN3 is a potential therapeutic target for breast cancer.

Involvement of acid-sensing ion channel 1a in gastric carcinoma cell migration and invasion

Acidic microenvironment, particularly acid-sensing ion channel 1a (ASIC1a), has been reported to promote carcinoma cell proliferation as well as migration. In this study, we explored the effect of ASIC1a on migration and invasion of gastric carcinoma (GC). ASIC1a expression levels were examined in paired GC and adjacent normal tissues from 16 patients by immunohistochemistry. Reverse transcription real-time PCR and immunoblotting were conducted to assess the ASIC1a expression levels in the GC cell line AGS after transfection with ASIC1a small hairpin RNA (shRNA). Wound healing and transwell invasion assays were utilized to detect metastasis and invasion following ASIC1a silencing. Tumor formation was used to detect the role of ASIC1a in tumorigenicity in vivo. It was found that ASIC1a expression level was significantly higher in GC tissues showing postoperative metastasis compared with non-metastasis and non-tumor tissues. Moreover, silencing of ASIC1a with shRNA significantly down-regulated ASIC1a expression and reduced GC cell migration and invasion. A moderately acidic extracellular environment inhibited GC cell viability. Furthermore, ASIC1a shRNA caused inhibition of tumorigenicity in vivo. Our study is the first report of attenuating the malignant phenotype of GC in vitro and in vivo by suppressing ASIC1a, and suggests a novel approach to study the relationship between ASICs and GC cell migration and invasion.

ZKSCAN3 promotes bladder cancer cell proliferation, migration, and invasion

The expression status of ZKSCAN3, a zinc-finger transcription factor containing KRAB and SCAN domains, as well as its biological significance, in human bladder cancer remains largely unknown. In the current study, we aimed to determine the functional role of ZKSCAN3 in bladder cancer progression. Immunohistochemistry in tissue specimens detected ZKSCAN3 signals in 138 (93.2%) of 148 urothelial neoplasms, which was significantly higher than in non-neoplastic urothelial tissues [76 (84.4%) of 90; P=0.044]. Correspondingly, the levels of ZKSCAN3 gene were significantly elevated in bladder tumors, compared with those in adjacent normal-appearing bladder mucosae (P=0.008). In a validation set of tissue microarray, significantly higher ZKSCAN3 expression was observed in high-grade and/or muscle-invasive urothelial carcinomas than in low-grade and/or non-muscle-invasive tumors. Two bladder cancer cell lines, UMUC3 and 647V, were found to strongly express ZKSCAN3 protein/mRNA, whereas its expression in 5637 bladder cancer and SVHUC normal urothelium cell lines was very weak. ZKSCAN3 silencing via its short hairpin RNA (shRNA) in UMUC3 and 647V resulted in significant decreases in cell viability/colony formation, cell migration/invasion, and the expression of matrix metalloproteinase (MMP)-2/MMP-9 and oncogenes c-myc/FGFR3, as well as significant increases in apoptosis and the expression of tumor suppressor genes p53/PTEN. ZKSCAN3 overexpression in 5637 also induced cell growth and migration. In addition, ZKSCAN3-shRNA expression considerably retarded tumor formation as well as its subsequent growth in xenograft-bearing mice. These results suggest that ZKSCAN3 plays an important role in bladder cancer outgrowth. Thus, ZKSCAN3 inhibition has the potential of being a therapeutic approach for bladder cancer.

Zinc finger proteins in cancer progression

Zinc finger proteins are the largest transcription factor family in human genome. The diverse combinations and functions of zinc finger motifs make zinc finger proteins versatile in biological processes, including development, differentiation, metabolism and autophagy. Over the last few decades, increasing evidence reveals the potential roles of zinc finger proteins in cancer progression. However, the underlying mechanisms of zinc finger proteins in cancer progression vary in different cancer types and even in the same cancer type under different types of stress. Here, we discuss general mechanisms of zinc finger proteins in transcription regulation and summarize recent studies on zinc finger proteins in cancer progression. In this review, we also emphasize the importance of further investigations in elucidating the underlying mechanisms of zinc finger proteins in cancer progression.

HMGB1 Promotes Mitochondrial Dysfunction-Triggered Striatal Neurodegeneration via Autophagy and Apoptosis Activation

Impairments in mitochondrial energy metabolism are thought to be involved in many neurodegenerative diseases. The mitochondrial inhibitor 3-nitropropionic acid (3-NP) induces striatal pathology mimicking neurodegeneration in vivo. Previous studies showed that 3-NP also triggered autophagy activation and apoptosis. In this study, we focused on the high-mobility group box 1 (HMGB1) protein, which is important in oxidative stress signaling as well as in autophagy and apoptosis, to explore whether the mechanisms of autophagy and apoptosis in neurodegenerative diseases are associated with metabolic impairment. To elucidate the role of HMGB1 in striatal degeneration, we investigated the impact of HMGB1 on autophagy activation and cell death induced by 3-NP. We intoxicated rat striata with 3-NP by stereotaxic injection and analyzed changes in expression HMGB1, proapoptotic proteins caspase-3 and phospho-c-Jun amino-terminal kinases (p-JNK). 3-NP–induced elevations in p-JNK, cleaved caspase-3, and autophagic marker LC3-II as well as reduction in SQSTM1 (p62), were significantly reduced by the HMGB1 inhibitor glycyrrhizin. Glycyrrhizin also significantly inhibited 3-NP–induced striatal damage. Neuronal death was replicated by exposing primary striatal neurons in culture to 3-NP. It was clear that HMGB1 was important for basal autophagy which was shown by rescue of cells through HMGB1 targeting shRNA approach.3-NP also induced the expression of HMGB1, p-JNK, and LC3-II in striatal neurons, and p-JNK expression was significantly reduced by shRNA knockdown of HMGB1, an effect that was reversed by exogenously increased expression of HMGB1. These results suggest that HMGB1 plays important roles in signaling for both autophagy and apoptosis in neurodegeneration induced by mitochondrial dysfunction.

Transcription factors and cognate signalling cascades in the regulation of autophagy

Autophagy is a process that maintains the equilibrium between biosynthesis and the recycling of cellular constituents; it is critical for avoiding the pathophysiology that results from imbalance in cellular homeostasis. Recent reports indicate the need for the design of high-throughput screening assays to identify targets and small molecules for autophagy modulation. For such screening, however, a better understanding of the regulation of autophagy is essential. In addition to regulation by various signalling cascades, regulation of gene expression by transcription factors is also critical. This review focuses on the various transcription factors as well as the corresponding signalling molecules that act together to translate the stimuli to effector molecules that up- or downregulate autophagy. This review rationalizes the importance of these transcription factors functioning in tandem with cognate signalling molecules and their interfaces as possible therapeutic targets for more specific pharmacological interventions.

Expression of acid-sensing ion channels in nucleus pulposus cells of the human intervertebral disk is regulated by non-steroid anti-inflammatory drugs

Non-steroid anti-inflammatory drugs (NSAIDs) are generally used in the treatment of inflammation and pain through cyclooxygenase (COX) inhibition. Mounting evidence has indicated additional COX-independent targets for NSAIDs including acid-sensing ion channels (ASICs) 1a and 3. However, detailed function and mechanism of ASICs still remain largely elusive. In this study, the impact of NSAIDs on ASICs in nucleus pulposus cells of the human intervertebral disk was investigated. Nucleus pulposus cells were isolated and cultured from protruded disk tissues of 40 patients. It was shown that ASIC1a and ASIC3 were expressed and functional in these cells by analyzing proton-gated currents after ASIC inhibition. We further investigated the neuroprotective capacity of ibuprofen (a COX inhibitor), psalmotoxin-1 (PcTX1, a tarantula toxin specific for homomeric ASIC1a), and amiloride (a classic inhibitor of the epithelial sodium channel ENaC/DEG family to which ASICs belong). PcTX1-containing venom has been shown to be comparable with amiloride in its neuroprotective features in rodent models of ischemia. Taken together, our data showed that amiloride, PcTX1, and ibuprofen decreased ASIC protein expression and thereby exerted protective effects from ASIC inhibition-mediated cell damage.

Recurrent patterns of DNA methylation in the ZNF154, CASP8, and VHL promoters across a wide spectrum of human solid epithelial tumors and cancer cell lines

The study of aberrant DNA methylation in cancer holds the key to the discovery of novel biological markers for diagnostics and can help to delineate important mechanisms of disease. We have identified 12 loci that are differentially methylated in serous ovarian cancers and endometrioid ovarian and endometrial cancers with respect to normal control samples. The strongest signal showed hypermethylation in tumors at a CpG island within the ZNF154 promoter. We show that hypermethylation of this locus is recurrent across solid human epithelial tumor samples for 15 of 16 distinct cancer types from TCGA. Furthermore, ZNF154 hypermethylation is strikingly present across a diverse panel of ENCODE cell lines, but only in those derived from tumor cells. By extending our analysis from the Illumina 27K Infinium platform to the 450K platform, to sequencing of PCR amplicons from bisulfite treated DNA, we demonstrate that hypermethylation extends across the breadth of the ZNF154 CpG island. We have also identified recurrent hypomethylation in two genomic regions associated with CASP8 and VHL. These three genes exhibit significant negative correlation between methylation and gene expression across many cancer types, as well as patterns of DNaseI hypersensitivity and histone marks that reflect different chromatin accessibility in cancer vs. normal cell lines. Our findings emphasize hypermethylation of ZNF154 as a biological marker of relevance for tumor identification. Epigenetic modifications affecting the promoters of ZNF154, CASP8, and VHL are shared across a vast array of tumor types and may therefore be important for understanding the genomic landscape of cancer.

The role of chaperone-mediated autophagy in huntingtin degradation

Huntington Disease (HD) is caused by an abnormal expansion of polyQ tract in the protein named huntingtin (Htt). HD pathology is featured by accumulation and aggregation of mutant Htt in striatal and cortical neurons. Aberrant Htt degradation is implicated in HD pathogenesis. The aim of this study was to investigate the regulatory role of chaperone-mediated autophagy (CMA) components, heat shock protein cognate 70 (Hsc70) and lysosome-associated protein 2A (LAMP-2A) in degradation of Htt fragment 1-552aa (Htt-552). A cell model of HD was produced by overexpression of Htt-552 with adenovirus. The involvement of CMA components in degradation of Htt-552 was determined with over-expression or silencing of Hsc70 and LAMP-2A. The results confirmed previous reports that both macroautophagy and CMA were involved in degradation of Htt-552. Changing the levels of CMA-related proteins affected the accumulation of Htt-552. The lysosomal binding and luminal transport of Htt-552 was demonstrated by incubation of Htt-552 with isolated lysosomes. Expansion of the polyQ tract in Htt-552 impaired its uptake and degradation by lysosomes. Mutation of putative KFERQ motif in wild-type Htt-552 interfered with interactions between Htt-552 and Hsc70. Endogenous Hsc70 and LAMP-2A interacted with exogenously expressed Htt-552. Modulating the levels of CMA related proteins degraded endogenous full-length Htt. These studies suggest that Hsc70 and LAMP-2A through CMA play a role in the clearance of Htt and suggest a novel strategy to target the degradation of mutant Htt.