Overexpression of Aristaless-Like Homeobox-4 Inhibits Proliferation, Invasion, and EMT in Hepatocellular Carcinoma Cells

PRC2 mediated KLF2 down regulation: a therapeutic and diagnostic axis during tumor progression

Surgery and chemo-radiotherapy are used as the common first-line treatment options in many cancers. However, tumor relapse is observed in many cancer patients following such first-line treatments. Therefore, targeted therapy according to the molecular cancer biology can be very important in reducing tumor recurrence. In this regard, a wide range of monoclonal antibodies against the growth factors and their receptors can offer more targeted treatment in cancer patients. However, due to the importance of growth factors in the normal biology of body cells, side effects can also be observed following the application of growth factor inhibitors. Therefore, more specific factors should be introduced as therapeutic targets with less side effects. Krüppel-like factors 2 (KLF2) belongs to the KLF family of transcription factors that are involved in the regulation of many cellular processes. KLF2 deregulations have been also reported during the progression of many tumors. In the present review we discussed the molecular mechanisms of KLF2 during tumor growth and invasion. It has been shown that the KLF2 as a tumor suppressor is mainly inhibited by the non-coding RNAs (ncRNAs) through the polycomb repressive complex 2 (PRC2) recruitment. This review is an effective step towards introducing the KLF2 as a suitable diagnostic and therapeutic target in cancer patients.

circKLHL24 Blocks Breast Cancer Development by Regulating the miR-1204/ALX4 Network

Background: Breast cancer is a major challenge affecting women's survival. Circular RNAs have been demonstrated to be vital regulators in the pathogenesis of human cancers. The authors' objective was to determine the functional role and mechanism of circKLHL24 in breast cancer development. Materials and Methods: The expression of circKLHL24, miR-1204, and aristaless-like 4 (ALX4) mRNA was measured using quantitative real-time polymerase chain reaction. The effects on cell viability, proliferation, migration/invasion, and glycolysis were identified using the Cell Counting Kit-8 (CCK-8) assay, colony formation assay, Transwell assay, and glycolysis stress test, respectively. For glycolysis progression analysis, glucose consumption and lactate production were assessed using corresponding kits, and the expression of glycolysis-related proteins was detected by Western blot. The putative interactions between miR-1204 and circKLHL24 or ALX4 were validated by dual-luciferase reporter assay or RNA pull-down assay. The expression of ALX4 at the protein level was detected by Western blot. Animal study was performed to clarify the role of circKLHL24 in vivo. Results: circKLHL24 and ALX4 were downregulated, while miR-1204 was upregulated in breast cancer tissues and cells. circKLHL24 overexpression blocked cell viability, colony formation, migration/invasion, and glycolysis progression. circKLHL24 competitively targeted miR-1204, and miR-1204 reintroduction reversed the effects of circKLHL24 restoration. miR-1204 bound to ALX4, and circKLHL24 sponged miR-1204 to upregulate ALX4. Cell viability, colony formation, migration/invasion, and glycolysis progression suppressed by miR-1204 deficiency were recovered by ALX4 knockdown. Besides, circKLHL24 blocked tumor growth in vivo by regulating miR-1204 and ALX4. Conclusions: circKLHL24 blocked the progression of breast cancer by activating ALX4 through targeting miR-1204, which might be a novel perspective to understand the pathogenesis of breast cancer.

Characterization of Associated Nonclassical Phenotypes in Patients with Deletion in the WAGR Region Identified by Chromosomal Microarray: New Insights and Literature Review

WAGR syndrome (Wilms' tumor, aniridia, genitourinary changes, and intellectual disability) is a contiguous gene deletion syndrome characterized by the joint deletion of PAX6 and WT1 genes, located in the short arm of chromosome 11. However, most deletions include other genes, leading to multiple associated phenotypes. Therefore, understanding how genes deleted together can contribute to other clinical phenotypes is still considered a challenge. In order to establish genotype-phenotype correlation in patients with interstitial deletions of the short arm of chromosome 11, we selected 17 patients with deletions identified by chromosomal microarray analysis: 4 new subjects and 13 subjects previously described in the literature with detailed clinical data. Through the analysis of deleted regions and the phenotypic changes, it was possible to suggest the contribution of specific genes to several nonclassical phenotypes, contributing to the accuracy of clinical characterization of the syndrome and emphasizing the broad phenotypic spectrum found in the patients. This study reports the first patient with a PAX6 partial deletion who does not present any eye anomaly thus opening a new set of questions about the functional activity of PAX6.

HES1 is a novel downstream modifier of the SHH-GLI3 Axis in the development of preaxial polydactyly

Sonic Hedgehog/GLI3 signaling is critical in regulating digit number, such that Gli3-deficiency results in polydactyly and Shh-deficiency leads to digit number reductions. SHH/GLI3 signaling regulates cell cycle factors controlling mesenchymal cell proliferation, while simultaneously regulating Grem1 to coordinate BMP-induced chondrogenesis. SHH/GLI3 signaling also coordinates the expression of additional genes, however their importance in digit formation remain unknown. Utilizing genetic and molecular approaches, we identified HES1 as a downstream modifier of the SHH/GLI signaling axis capable of inducing preaxial polydactyly (PPD), required for Gli3-deficient PPD, and capable of overcoming digit number constraints of Shh-deficiency. Our data indicate that HES1, a direct SHH/GLI signaling target, induces mesenchymal cell proliferation via suppression of Cdkn1b, while inhibiting chondrogenic genes and the anterior autopod boundary regulator, Pax9. These findings establish HES1 as a critical downstream effector of SHH/GLI3 signaling in the development of PPD.

Sonic Hedgehog/GLI3 signaling is critical in regulating digit number, such that Gli3-deficiency results in additional digits and Shh-deficiency leads to digit number reductions. SHH/GLI3 signaling within the developing limb regulates numerous genes critical for proper autopod (hand/foot) development, however not all target genes are known to be truly important for digit formation. Utilizing genetic and molecular approaches, we identified HES1 as a downstream modifier of the SHH/GLI signaling axis capable of inducing preaxial polydactyly (PPD), required for Gli3-deficient PPD, and capable of overcoming digit number constraints of Shh-deficiency. We further propose a mechanistic model by which HES1 coordinates the expression of genes important for proper digit development. These findings establish HES1 as a critical downstream effector of SHH/GLI3 signaling in the development of PPD.

Circular RNA Circ_0000098 Elevates ALX4 Expression via Adsorbing miR-1204 to Inhibit the Progression of Hepatocellular Carcinoma

Background

Circular RNAs (CircRNAs) feature prominently in the progression of various cancers. However, the biological functions of many circRNAs in hepatocellular carcinoma (HCC) are far from fully clarified. This work is performed to decipher the function of circ_0000098 (circSLC30A7) in modulating the progression of HCC and its molecular mechanism.

Methods

Microarray data (GSE97332) were available from the Gene Expression Omnibus (GEO) database, and circRNA differentially expressed in HCC tissues was screened out by GEO2R tool. Circ_0000098, microRNA-1204 (miR-1204), and aristaless-like homeobox-4 (ALX4) mRNA expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell counting kit-8 (CCK-8), scratch wound healing, and Transwell assays were adopted to determine proliferation, migration, and invasion of HCC cells. ALX4 protein, E-cadherin, N-cadherin, and Vimentin expressions were evaluated by Western blot. In addition, the targeting relationship between miR-1204 and circ_0000098 or ALX4 was studied with dual-luciferase reporter assay and RIP assay.

Results

Circ_0000098 expression level was markedly declined in HCC tissues and cells, and its underexpression was associated with larger tumor size of HCC patients. Knocking down circ_0000098 observably promoted the multiplication, migration, invasion, and epithelial-mesenchymal transition (EMT) of Huh7 and SMMC-7721 cells. Additionally, circ_0000098 was mainly distributed in the cytoplasm of HCC cells, and up-regulated ALX4 expression through competitively decoying miR-1204.

Conclusion

Circ_0000098, as a competitive endogenous RNA (ceRNA) of miR-1204, upregulates ALX4 expression and suppresses the growth, migration, invasion, and EMT of HCC cells.

Deficiency of STING Signaling in Embryonic Cerebral Cortex Leads to Neurogenic Abnormalities and Autistic-Like Behaviors

STING is known as a central adaptor for sensing cytosolic DNA sensing. Recent studies have provided evidence that STING response is divergent among different cell types. Here, this work demonstrates that STING controls neural progenitor cells (NPCs) by sensing DNA damage in NPCs. The deletion of STING reduces neuronal differentiation and increases proliferation of mouse and human NPCs. Furthermore, STINGcKO mice display autistic-like behaviors. In NPCs, STING specifically recruits IKKβ and activates nuclear factor κB (NF-κB) through phosphorylation. NF-κB binds to ALX4 promoter and triggers ALX4 transcription. In addition, tumor necrosis factor α, an activator of NF-κB, can rescue some phenotypes caused by STING deletion in mice. Together, the findings show that STING signaling is essential for neuronal gene expression program and has profound consequences on brain function.

Overexpression of circ_0001445 decelerates hepatocellular carcinoma progression by regulating miR-942-5p/ALX4 axis

Circular RNAs (circRNAs) have been verified to have essential regulatory roles in diverse human cancers, including hepatocellular carcinoma (HCC). In this study, we aimed to explore the roles of circ_0001445 in HCC. Herein, circ_0001445 was decreased and miR-942-5p was increased in HCC tissues and cells. Circ_0001445 overexpression or miR-942-5p inhibition repressed cell cycle process, migration, invasion, epithelial-mesenchymal transition and glycolysis in HCC cells. Mechanistically, circ_0001445 could promote ALX4 expression through targeting miR-942-5p. Moreover, miR-942-5p overexpression reversed the inhibitory effect of circ_0001445 on HCC cell progression. The effect of miR-942-5p on HCC cell development was rescued following the elevation of ALX4. In addition, circ_0001445 overexpression restrained tumorigenesis in vivo. In conclusion, circ_0001445 played a negative role in HCC progression by modulating miR-942-5p/ALX4 axis, which might provide a novel target for HCC therapy.

miR-1470 regulates cell proliferation and apoptosis by targeting ALX4 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. MicroRNAs (miRNAs) have been proven to play essential roles in different cancers, including HCC. The current study was mainly focused on the role of miR-1470 in HCC progression.

METHODS

Quantitative real-time PCR (qRT-PCR) was performed to detect the expression levels of miR-1470 and Aristaless-like homeobox-4 (ALX4). The CCK-8 and EdU assays were used to examine cell proliferation. Flow cytometric analysis was used to elucidate the cell cycle and cell apoptosis. A xenograft tumor assay was carried out to verify the effect of miR-1470 on tumor formation in vivo.

RESULTS

According to the qRT-PCR assay, miR-1470 was proven to be overexpressed in HCC. As shown by the CCK-8 assay, EdU assay and flow cytometric analysis, miR-1470 overexpression promoted cell proliferation and inhibited cell apoptosis. ALX4 was proven via a dual luciferase reporter assay to be a downstream target gene of miR-1470. ALX4 was downregulated in HCC. The results of a rescue assay revealed that miR-1470 had an oncogenic role in HCC by regulating ALX4.

CONCLUSION

miR-1470 exhibits an oncogenic role in HCC by targeting ALX4. The data from our study may provide novel insight for the identification of new biomarkers and treatment strategies for HCC.

Epigenetic silencing of ALX4 regulates microcystin-LR induced hepatocellular carcinoma through the P53 pathway

Recent studies have shown that microcystin-LR (MC-LR) is one of the principal factors that cause liver cancer. Previously we have found that Aristaless-like Homeobox 4 (ALX4) was differentially expressed in MC-LR-induced malignant transformed L02 cells. However, the expression regulation, role and molecular mechanism of ALX4 during the process of liver cancer induced by MC-LR are still unclear. The expression of ALX4 was detected by quantitative reverse-transcription PCR and Western blot in MC-LR induced malignantly transformed cell and rat models. Methylation status of ALX4 promoter region was evaluated by methylation-specific PCR and bisulfite genomic sequencing. The anti-tumor effects of ALX4 on MC-LR induced liver cancer were identified in vitro and in vivo. ALX4 expression was progressively down-regulated in MC-LR-induced malignantly transformed L02 cells and the MC-LR exposed rat models. ALX4 promoter regions were highly methylated in malignantly transformed cells, while treatment with demethylation agent 5-aza-dC significantly increased ALX4 expression. Functional studies showed that overexpression of ALX4 inhibits cell proliferation, migration, invasion and metastasis in vitro and in vivo, blocks the G1/S phase and promotes the apoptosis. Conversely, knockdown of ALX4 promotes cell proliferation, migration and invasion. Mechanism study found that ALX4 exerts its antitumor function through the P53 pathway, C-MYC and MMP9. More importantly, ALX4 expression level showed a negative relation with serum MC-LR levels in patients with hepatocellular carcinoma. Our results suggested that ALX4 was inactivated by DNA methylation and played a tumor suppressor function through the P53 pathway in MC-LR induced liver cancer.

Homeobox Genes and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common type of cancer, and is the third leading cause of cancer-related deaths each year. It involves a multi-step progression and is strongly associated with chronic inflammation induced by the intake of environmental toxins and/or viral infections (i.e., hepatitis B and C viruses). Although several genetic dysregulations are considered to be involved in disease progression, the detailed regulatory mechanisms are not well defined. Homeobox genes that encode transcription factors with homeodomains control cell growth, differentiation, and morphogenesis in embryonic development. Recently, more aberrant expressions of Homeobox genes were found in a wide variety of human cancer, including HCC. In this review, we summarize the currently available evidence related to the role of Homeobox genes in the development of HCC. The objective is to determine the roles of this conserved transcription factor family and its potential use as a therapeutic target in future investigations.

Krüppel-like factor 2 inhibits hepatocarcinogenesis through negative regulation of the Hedgehog pathway

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The most important reason for the occurrence of HCC is hepatitis C or B infection. Moreover, genetic factors play an important role in the tumorigenesis of HCC. Here, we demonstrated that Krüppel-like factor 2 (KLF2) expression was downregulated in HCC samples compared with adjacent tissues. Additionally, KLF2 was shown to inhibit the growth, migration and colony-formation ability of liver cancer cells. Further mechanistic studies revealed that KLF2 can compete with Gli1 for interaction with HDAC1 and restrains Hedgehog signal activation. Together, our results suggest that KLF2 has potential as a diagnostic biomarker and therapeutic target for the treatment of HCC.

Overexpression of ALK4 inhibits cell proliferation and migration through the inactivation of JAK/STAT3 signaling pathway in glioma

Aristaless-like homeobox 4 (ALK4) is a member of ALK proteins family and plays an important role in tumorigenesis. However, the expression and function of ALK4 in glioma remain largely unknown. The aim of our study was to elucidate its expression pattern in human glioma tissues and cell lines, as well as its functions in glioma cells. Our results demonstrated that ALK4 was lowly expressed in human glioma tissues and cell lines. Additionally, overexpression of ALK4 significantly suppressed the proliferation, migration and invasion of glioma cells, as well as inhibited the epithelial-mesenchymal transition (EMT) phenotype in glioma cells. Furthermore, overexpression of ALK4 significantly downregulated the phosphorylation levels of JAK2 and STAT3 in U87 cells. STAT3 inhibitor (Niclosamide) obviously enhanced ALK4-inhibted glioma cell proliferation and invasion. In conclusion, we demonstrated that overexpression of ALK4 suppressed glioma cell proliferation, migration and invasion through the inactivation of JAK/STAT3 signaling pathway. Thus, ALK4 may be a potential therapeutic target for the treatment of glioma.

ALX4, an epigenetically down regulated tumor suppressor, inhibits breast cancer progression by interfering Wnt/β-catenin pathway

Background

ALX4 is a paired-like homedomain transcription factor mainly expressed in the mesenchymal compartment of variety of developing tissues, but its functions, regulation mechanisms and clinical values in breast cancer remains unclear.

Methods

The expression of ALX4 in breast cancer cell lines and patients’ tissues were detected by RT-PCR, qPCR and western blot. Furthermore TCGA database was applied to confirm these results. MSP and BSP methods were used to assess the methylation of ALX4 promoter region. In vitro proliferation, metastasis and in vivo nude mice model were used to evaluate the anti-tumor effect of ALX4 on breast cancer cell lines. Luciferase reporter assay, western blot and TCGA database were used to investigate the tumor suppression mechanisms of ALX4. TMA of 142 breast patients was generated to evaluate the clinical significance of ALX4.

Results

Expression analysis revealed that ALX4 expression is down regulated in breast cancer cell lines and tissues. MSP study showed that the promoter region of ALX4 was hyper-methylated 100% (3/3) in breast cancer cell lines and 69.44% (75/108) in primary breast tumors tissues while 0% (0/8) in normal breast tissues. 5-aza-dc de-methylation treatment restored ALX4 expression in breast cancer cell lines. Functional studies showed that ectopic expression of ALX4 in breast cancer cells inhibited cell proliferation, metastasis in vitro and in vivo. Mechanism study found that ALX4 exerted its anti-tumor function by suppressing the Wnt/β-catenin pathway through promoting the phosphorylation degradation of β-catenin in a GSK3β dependent manner. Clinically multivariate analysis showed that ALX4 expression was an independent favorable prognostic factor in breast cancer patients.

Conclusions

We reveal for the first time that ALX4 acts as a novel functional tumor suppressor inactivated by DNA methylation and is an independent prognostic factor in breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0643-9) contains supplementary material, which is available to authorized users.

Long non-coding RNA DLX6-AS1 aggravates hepatocellular carcinoma carcinogenesis by modulating miR-203a/MMP-2 pathway

Long non-coding RNAs (lncRNAs) have been wildly verified to modulate multiple tumorigenesis, especially hepatocellular carcinoma (HCC). In present study, our team aims to investigate the role of lncRNA DLX6-AS1 in the HCC carcinogenesis. Results of early-stage experiments found that DLX6-AS1 expression level was up-regulated in 60 cases of HCC tissue samples compared with adjacent normal tissue. Moreover, the aberrant overexpression of DLX6-AS1 indicated the poor prognosis of HCC patients. Loss-of-function experiments revealed that DLX6-AS1 knockdown inhibited the proliferation, migration and invasion of HCC cells in vitro, and decreased the tumor growth in vivo. Bioinformatics analysis predicted that miR-203a potentially targeted DLX6-AS1 3'-UTR, suggesting the interaction between miR-203a and DLX6-AS1. Furthermore, miR-203a also targeted MMP-2 mRNA 3'-UTR, which was validated by luciferase reporter assay. Taken together, our study discovered the oncogenic role of DLX6-AS1 in clinical specimens and cellular experiments, showing the potential DLX6-AS1/miR-203a/MMP-2 pathway. This results and findings provide a novel insight for HCC tumorigenesis.

Upstream regulation for initiation of restricted Shh expression in the chick limb bud

BACKGROUND

The organizing center, which serves as a morphogen source, has crucial functions in morphogenesis in animal development. The center is necessarily located in a certain restricted area in the morphogenetic field, and there are several ways in which an organizing center can be restricted. The organizing center for limb morphogenesis, the ZPA (zone of polarizing activity), specifically expresses the Shh gene and is restricted to the posterior region of the developing limb bud.

RESULTS

The pre-pattern along the limb anteroposterior axis, provided by anterior Gli3 expression and posterior Hand2 expression, seems insufficient for the initiation of Shh expression restricted to a narrow, small spot in the posterior limb field. Comparison of the spatiotemporal patterns of gene expression between Shh and some candidate genes (Fgf8, Hoxd10, Hoxd11, Tbx2, and Alx4) upstream of Shh expression suggested that a combination of these genes' expression provides the restricted initiation of Shh expression.

CONCLUSIONS

Taken together with results of functional assays, we propose a model in which positive and negative transcriptional regulatory networks accumulate their functions in the intersection area of their expression regions to provide a restricted spot for the ZPA, the source of morphogen, Shh. Developmental Dynamics 246:417-430, 2017. © 2017 Wiley Periodicals, Inc.