The SLC34A2-ROS-HIF-1-induced up-regulation of EZH2 expression promotes proliferation and chemo-resistance to apoptosis in colorectal cancer

Therapeutic potential of tLyp-1-EV-shCTCF in inhibiting liver cancer stem cell self-renewal and immune escape via SALL3 modulation in hepatocellular carcinoma

The progression of hepatocellular carcinoma (HCC) is influenced by disrupted metabolic processes, presenting challenges in prognostic outcomes. Hepatocellular carcinoma (HCC), a leading cause of cancer-related mortality, is closely associated with metabolic reprogramming and stem cell-like properties in liver cancer stem cells (LCSCs). This study explored the potential molecular mechanisms by which tLyP-1-modified extracellular vesicles (EVs) delivering CTCF shRNA (tLyp-1-EV-shCTCF) regulate mitochondrial DNA methylation-induced glycolytic metabolic reprogramming and LCSC self-renewal. Through a series of methods, including Western blot, nanoparticle tracking analysis, and immunofluorescence, we demonstrated the successful delivery and internalization of tLyp-1-EV in HCC cells. Our results identified SALL3 as a critical factor underexpressed in HCC and LCSCs, while CTCF was overexpressed. Overexpression of SALL3 inhibited LCSC self-renewal and immune evasion by blocking the CTCF-DNMT3A interaction, thus repressing DNMT3A methyltransferase activity and subsequent mitochondrial DNA methylation-mediated glycolytic metabolic reprogramming. In vivo experiments further supported these findings, showing that tLyp-1-EV-shCTCF treatment significantly reduced tumor growth by upregulating SALL3 expression, thereby inhibiting glycolytic metabolic reprogramming and enhancing the immune response against HCC cells. This study provides novel insights into the role of SALL3 and mitochondrial DNA methylation in HCC progression, offering potential therapeutic targets for combating HCC and its stem cell-like properties.

Comparative genomics reveals convergent signals associated with the high metabolism and longevity in birds and bats

Birds and bats have long lifespans relative to their body size compared with non-flying animals. However, the genomic basis associated with longer lifespan of flying species despite their higher metabolism was unclear. In this study, we hypothesized that genes involved in the regulation of metabolism and lifespan changed with the acquisition of flight and searched for genes that show specific evolutionary patterns in flying species. As a result, we identified several genes that show different evolutionary rates in bird and bat lineages. Genes in pathways involved in lifespan regulation were conserved in birds, while they evolved at an accelerated rate in bats. We also searched for genes in which convergent amino acid substitutions occurred in birds and bats and found such substitutions in genes involved in cancer, reactive oxygen species control and immunity. Our study revealed genomic changes associated with the acquisition of flight in birds and bats and suggested that multiple genes involved in the regulation of lifespan and metabolism support both high metabolism and longevity in flying species.

Hypoxia makes EZH2 inhibitor not easy-advances of crosstalk between HIF and EZH2

Histone methylation plays a crucial role in tumorigenesis. Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that regulates chromatin structure and gene expression. EZH2 inhibitors (EZH2is) have been shown to be effective in treating hematologic malignancies, while their effectiveness in solid tumors remains limited. One of the major challenges in the treatment of solid tumors is their hypoxic tumor microenvironment. Hypoxia-inducible factor 1-alpha (HIF-1α) is a key hypoxia responder that interacts with EZH2 to promote tumor progression. Here we discuss the implications of the relationship between EZH2 and hypoxia for expanding the application of EZH2is in solid tumors.

Drp1-mediated mitochondrial fission promotes pulmonary fibrosis progression through the regulation of lipid metabolic reprogramming by ROS/HIF-1α

OBJECTIVE

To confirm the mechanism of dynamic-related protein 1 (Drp1)-mediated mitochondrial fission through ROS/HIF-1α-mediated regulation of lipid metabolic reprogramming in the progression of pulmonary fibrosis (PF).

METHODS

A mouse model of PF was established by intratracheal instillation of bleomycin (BLM) (2.5 mg/kg). A PF cell model was constructed by stimulating MRC-5 cells with TGF-β (10 ng/mL). Pathological changes in the lung tissue and related protein levels were observed via tissue staining. The indicators related to lipid oxidation were detected by a kit, and lipid production was confirmed through oil red O staining. Inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). RT-qPCR, Western blotting and immunofluorescence staining were used to detect the expression of genes and proteins related to the disease. We used CCK-8 and EdU staining to confirm cell proliferation, flow cytometry was used to confirm apoptosis and ROS levels, α-SMA expression was detected by immunofluorescence staining, and mitochondria were observed by MitoTracker staining.

RESULTS

The BLM induced lung tissue structure and alveolar wall thickening in mice. Mitochondrial fission was observed in MRC-5 cells induced by TGF-β, which led to increased cell proliferation; decreased apoptosis; increased expression of collagen, α-SMA and Drp1; and increased lipid oxidation and inflammation. Treatment with the Drp1 inhibitor mdivi-1 or transfection with si-Drp1 attenuated the induction of BLM and TGF-β. For lipid metabolism, lipid droplets were formed in BLM-induced lung tissue and in TGF-β-induced cells, fatty acid oxidation genes and lipogenesis-related genes were upregulated, ROS levels in cells were increased, and the expression of HIF-1α was upregulated. Mdivi-1 treatment reversed TGF-β induction, while H2O2 treatment or OE-HIF-1α transfection reversed the effect of mdivi-1.

CONCLUSION

In PF, inhibition of Drp1 can prevent mitochondrial fission in fibroblasts and regulate lipid metabolism reprogramming through ROS/HIF-1α; thus, fibroblast activation was inhibited, alleviating the progression of PF.

Epigenetic reprogramming of T cells: unlocking new avenues for cancer immunotherapy

T cells, a key component of cancer immunotherapy, undergo a variety of histone modifications and DNA methylation changes since their bone marrow progenitor stages before developing into CD8+ and CD4+ T cells. These T cell types can be categorized into distinct subtypes based on their functionality and properties, such as cytotoxic T cells (Tc), helper T cells (Th), and regulatory T cells (Treg) as subtypes for CD8+ and CD4+ T cells. Among these, the CD4+ CD25+ Tregs potentially contribute to cancer development and progression by lowering T effector (Teff) cell activity under the influence of the tumor microenvironment (TME). This contributes to the development of therapeutic resistance in patients with cancer. Subsequently, these individuals become resistant to monoclonal antibody therapy as well as clinically established immunotherapies. In this review, we delineate the different epigenetic mechanisms in cancer immune response and its involvement in therapeutic resistance. Furthermore, the possibility of epi-immunotherapeutic methods based on histone deacetylase inhibitors and histone methyltransferase inhibitors are under investigation. In this review we highlight EZH2 as the principal driver of cancer cell immunoediting and an immune escape regulator. We have addressed in detail how understanding T cell epigenetic regulation might bring unique inventive strategies to overcome drug resistance and increase the efficacy of cancer immunotherapy.

The Role of Hypoxia on the Trimethylation of H3K27 in Podocytes

Epigenetic alterations contribute to the pathogenesis of chronic diseases such as diabetes mellitus. Previous studies of our group showed that diabetic conditions reduce the trimethylation of H3K27 in podocytes in a NIPP1- (nuclear inhibitor of protein phosphatase 1) and EZH2- (enhancer of zeste homolog 2) dependent manner. It has been previously reported that in differentiated podocytes, hypoxia decreases the expression of slit diaphragm proteins and promotes foot process effacement, thereby contributing to the progression of renal disease. The exact mechanisms are, however, not completely understood. The aim of this study was to analyze the role of hypoxia and HIFs (hypoxia-inducible factor) on epigenetic changes in podocytes affecting NIPP1, EZH2 and H3K27me3, in vitro and in vivo. In vivo studies were performed with mice exposed to 10% systemic hypoxia for 3 days or injected with 3,4-DHB (dihydroxybenzoate), a PHD (prolyl hydroxylase) inhibitor, 24 h prior analyses. Immunodetection of H3K27me3, NIPP1 and EZH2 in glomerular podocytes revealed, to the best of our knowledge for the first time, that hypoxic conditions and pharmacological HIFs activation significantly reduce the expression of NIPP1 and EZH2 and diminish H3K27 trimethylation. These findings are also supported by in vitro studies using murine-differentiated podocytes.

Molecular Mechanisms and Risk Factors Related to the Pathogenesis of Peyronie's Disease

Peyronie's disease (PD) is a benign condition caused by plaque formation on the tunica albuginea of the penis. It is associated with penile pain, curvature, and shortening, and contributes to erectile dysfunction, which worsens patient quality of life. In recent years, research into understanding of the detailed mechanisms and risk factors involved in the development of PD has been increasing. In this review, the pathological mechanisms and several closely related signaling pathways, including TGF-β, WNT/β-catenin, Hedgehog, YAP/TAZ, MAPK, ROCK, and PI3K/AKT, are described. Findings regarding cross-talk among these pathways are then discussed to elucidate the complicated cascade behind tunica albuginea fibrosis. Finally, various risk factors including the genes involved in the development of PD are presented and their association with the disease summarized. The purpose of this review is to provide a better understanding regarding the involvement of risk factors in the molecular mechanisms associated with PD pathogenesis, as well as to provide insight into disease prevention and novel therapeutic interventions.

Hypoxia-mediated promotion of glucose metabolism in non-small cell lung cancer correlates with activation of the EZH2/FBXL7/PFKFB4 axis

F-box/LRR-repeat protein 7 (FBXL7) was predicted as a differentially expressed E3 ubiquitin ligase in non-small cell lung cancer (NSCLC), which has been suggested to influence cancer growth and metastasis. In this study, we aimed to decipher the function of FBXL7 in NSCLC and delineate the upstream and downstream mechanisms. FBXL7 expression was verified in NSCLC cell lines and GEPIA-based tissue samples, after which the upstream transcription factor of FBXL7 was bioinformatically identified. The substrate PFKFB4 of the FBXL7 was screened out by tandem affinity purification coupled with mass-spectrometry (TAP/MS). FBXL7 was downregulated in NSCLC cell lines and tissue samples. FBXL7 ubiquitinated and degraded PFKFB4, thus suppressing glucose metabolism and malignant phenotypes of NSCLC cells. Hypoxia-induced HIF-1α upregulation elevated EZH2 and inhibited FBXL7 transcription and reduced its expression, thus promoting PFKFB4 protein stability. By this mechanism, glucose metabolism and the malignant phenotype were enhanced. In addition, knockdown of EZH2 impeded tumor growth through the FBXL7/PFKFB4 axis. In conclusion, our work reveals that the EZH2/FBXL7/PFKFB4 axis plays a regulatory role in glucose metabolism and tumor growth of NSCLC, which is expected to be potential biomarkers for NSCLC.

Drp1 activates ROS/HIF-1α/EZH2 and triggers mitochondrial fragmentation to deteriorate hypercalcemia-associated neuronal injury in mouse model of chronic kidney disease

Background

Chronic kidney disease (CKD), characterized as renal dysfunction, is regarded as a major public health problem which carries a high risk of cardiovascular diseases. The purpose of this study is to evaluate the functional significance of Drp1 in hypercalcemia-associated neuronal damage following CKD and the associated mechanism.

Methods

Initially, the CKD mouse models were established. Next, RT-qPCR and Western blot analysis were performed to measure expression of Fis1 and Drp1 in CKD. Chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter gene assay were utilized to explore the relationship among Drp1, HIF-1α, EZH2, and ROS with primary cortical neurons isolated from neonatal mice. Next, CKD mice were subjected to calcitonin treatment or manipulation with adenovirus expressing sh-Drp1, so as to explore the effects of Drp1 on hypercalcemia-induced neuronal injury in CKD. TUNEL assay and immunofluorescence staining were performed to detect apoptosis and NeuN-positive cells (neurons) in prefrontal cortical tissues of CKD mice.

Results

It was found that hypercalcemia could induce neuronal injury in CKD mice. An increase of Fis1 and Drp1 expression in cerebral cortex of CKD mice correlated with mitochondrial fragmentation. Calcitonin suppressed Drp1/Fis1-mediated mitochondrial fragmentation to attenuate hypercalcemia-induced neuronal injury after CKD. Additionally, Drp1 could increase EZH2 expression through the binding of HIF-1α to EZH2 promoter via elevating ROS generation. Furthermore, Drp1 knockdown inhibited hypercalcemia-induced neuronal injury in CKD while overexpression of EZH2 could reverse this effect in vivo.

Conclusion

Taken together, the key findings of the current study demonstrate the promotive role of Drp1 in mitochondrial fragmentation which contributes to hypercalcemia-induced neuronal injury in CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02542-7.

HypoxaMIRs: Key Regulators of Hallmarks of Colorectal Cancer

Hypoxia in cancer is a thoroughly studied phenomenon, and the logical cause of the reduction in oxygen tension is tumor growth itself. While sustained hypoxia leads to death by necrosis in cells, there is an exquisitely regulated mechanism that rescues hypoxic cells from their fatal fate. The accumulation in the cytoplasm of the transcription factor HIF-1α, which, under normoxic conditions, is marked for degradation by a group of oxygen-sensing proteins known as prolyl hydroxylases (PHDs) in association with the von Hippel-Lindau anti-oncogene (VHL) is critical for the cell, as it regulates different mechanisms through the genes it induces. A group of microRNAs whose expression is regulated by HIF, collectively called hypoxaMIRs, have been recognized. In this review, we deal with the hypoxaMIRs that have been shown to be expressed in colorectal cancer. Subsequently, using data mining, we analyze a panel of hypoxaMIRs expressed in both normal and tumor tissues obtained from TCGA. Finally, we assess the impact of these hypoxaMIRs on cancer hallmarks through their target genes.

Synthetic strategy and structure-activity relationship (SAR) studies of 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1, Lificiguat): a review

Since 1994, YC-1 (Lificiguat, 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole) has been synthesized, and many targets for special bioactivities have been explored, such as stimulation of platelet-soluble guanylate cyclase, indirect elevation of platelet cGMP levels, and inhibition of hypoxia-inducible factor-1 (HIF-1) and NF-κB. Recently, Riociguat®, the first soluble guanylate cyclase (sGC) stimulator drug used to treat pulmonary hypertension and pulmonary arterial hypertension, was derived from the YC-1 structure. In this review, we aim to highlight the synthesis and structure–activity relationships in the development of YC-1 analogs and their possible indications.

Since 1994, YC-1 (Lificiguat) has been synthesized, and many targets for special bioactivities have been explored, such as stimulation of platelet-soluble guanylate cyclase, indirect elevation of platelet cGMP levels, and inhibition of HIF-1 and NF-κB.

Characterization of SLC34A2 as a Potential Prognostic Marker of Oncological Diseases

The main goal of this study is to consider SLC34A2 as a potential prognostic marker of oncological diseases using the mutational, expression, and survival data of cancer studies which are publicly available online. We collected data from four databases (cBioPortal, The Cancer Genome Atlas; cBioPortal, Genie; International Cancer Genome Consortium; ArrayExpress). In total, 111,283 samples were categorized according to 27 tumor locations. Ninety-nine functionally significant missense mutations and twelve functionally significant indel mutations in SLC34A2 were found. The most frequent mutations were SLC34A2-ROS1, p.T154A, p.P506S/R/L, p.G257A/E/R, p.S318W, p.A396T, p.P410L/S/H, p.S461C, p.A473T/V, and p.Y503H/C/F. The upregulation of SLC34A2 was found in samples of myeloid, bowel, ovarian, and uterine tumors; downregulation was found in tumor samples of breast, liver, lung, and skin cancer tumors. It was found that the life expectancy of breast and thymus cancer patients with an SLC34A2 mutation is lower, and it was revealed that SLC34A2 overexpression reduced the life span of patients with brain, ovarian, and pancreatic tumors. Thereby, for these types of oncological diseases, the mutational profile of SLC34A2 can be a potential prognostic marker for breast and thymus cancers, and the upregulation of SLC34A2 can be a potential prognostic marker for brain, ovarian, and pancreatic cancers.

SLC34A2 promotes cancer proliferation and cell cycle progression by targeting TMPRSS3 in colorectal cancer

Solute carrier family 34 member 2 (SLC34A2), a family member of sodium-driven phosphate cotransporters, has been reported to facilitate cell proliferation and tumor growth. However, the functional mechanism by which SLC34A2 promotes cell growth and cell cycle progression remains poorly understood. Here, we reported that SLC34A2 was overexpressed in CRC by analysis of TCGA and GEO datasets. A total of 45 differentially expressed genes (DEGs) were identified from comparing SLC34A2-high or -low groups and functional enrichment analysis of these DEGs demonstrated that cell cycle pathway was enriched. Interestingly, we found a positive correlation between TMPRSS3 (transmembrane serine protease 3) and SLC34A2, which was confirmed by RT-qPCR and western blotting. Furthermore, TMPRSS3 was also upregulated in CRC tumor tissues compared to normal tissues. Patients with high TMPRSS3 expression had poor prognosis. Functionally, TMPRSS3 deficiency inhibited cell proliferation and colony formation in CRC cells. TMPRSS3 overexpression in SLC34A2-deficient cells antagonized siSLC34A2-mediated cell cycle inhibition by promoting cyclin E, cyclin A protein expression. Based on these results, our study suggests that SLC34A2 promotes cancer proliferation and cell cycle progression by targeting TMPRSS3 in colorectal cancer cells.

Methylation Landscape: Targeting Writer or Eraser to Discover Anti-Cancer Drug

Cancer is a major global health challenge for our health system, despite the important pharmacological and therapeutic discoveries we have seen since past 5 decades. The increasing prevalence and mortality of cancer may be closely related to smoking, exposure to environmental pollution, dietary and genetic factors. Despite significant promising discoveries and developments such as cell and biotechnological therapies a new breakthrough in the medical field is needed to develop specific and effective drugs for cancer treatment. On the development of cell therapies, anti-tumor vaccines, and new biotechnological drugs that have already shown promising effects in preclinical studies. With the continuous enrichment and development of chromatin immunoprecipitation sequencing (ChIP-seq) and its derivative technologies, epigenetic modification has gradually become a research hotspot. As key ingredients of epigenetic modification, Writers, Readers, Erasers have been gradually unveiled. Cancer has been associated with epigenetic modification especially methylation and therefore different epigenetic drugs have been developed and some of those are already undergoing clinical phase I or phase II trials, and it is believed that these drugs will certainly assist the treatment in the near future. With respect to this, an overview of anti-tumor drugs targeting modified enzymes and de-modified enzymes will be performed in order to contribute to future research.

Uncovering the prognostic gene signatures for the improvement of risk stratification in cancers by using deep learning algorithm coupled with wavelet transform

Background

The aim of gene expression-based clinical modelling in tumorigenesis is not only to accurately predict the clinical endpoints, but also to reveal the genome characteristics for downstream analysis for the purpose of understanding the mechanisms of cancers. Most of the conventional machine learning methods involved a gene filtering step, in which tens of thousands of genes were firstly filtered based on the gene expression levels by a statistical method with an arbitrary cutoff. Although gene filtering procedure helps to reduce the feature dimension and avoid overfitting, there is a risk that some pathogenic genes important to the disease will be ignored.

Results

In this study, we proposed a novel deep learning approach by combining a convolutional neural network with stationary wavelet transform (SWT-CNN) for stratifying cancer patients and predicting their clinical outcomes without gene filtering based on tumor genomic profiles. The proposed SWT-CNN overperformed the state-of-art algorithms, including support vector machine (SVM) and logistic regression (LR), and produced comparable prediction performance to random forest (RF). Furthermore, for all the cancer types, we firstly proposed a method to weight the genes with the scores, which took advantage of the representative features in the hidden layer of convolutional neural network, and then selected the prognostic genes for the Cox proportional-hazards regression. The results showed that risk stratifications can be effectively improved by using the identified prognostic genes as feature, indicating that the representative features generated by SWT-CNN can well correlate the genes with prognostic risk in cancers and be helpful for selecting the prognostic gene signatures.

Conclusions

Our results indicated that gene expression-based SWT-CNN model can be an excellent tool for stratifying the prognostic risk for cancer patients. In addition, the representative features of SWT-CNN were validated to be useful for evaluating the importance of the genes in the risk stratification and can be further used to identify the prognostic gene signatures.

Identification of dysregulated miRNAs-genes network in ovarian cancer: An integrative approach to uncover the molecular interactions and oncomechanisms

Background

Ovarian (OV) cancer is considered as one of the most deadly malignancies in women, since it is unfortunately diagnosed in advanced stages. Nowadays, the importance of bioinformatics tools and their frequent usage in tracking dysregulated cancer‐related genes and pathways have been highlighted in researches.

Aim

The aim of this study is to investigate dysregulated miRNAs‐genes network and its function in OV tumors based on the integration of microarray data through a system biology approach.

Methods

Two microarray data (GSE119056 and GSE4122) were analyzed to explore the differentially expressed miRNAs (DEmiRs) and genes among OV tumors and normal tissues. Then, through the help of TargetScan, miRmap, and miRTarBase databases, the dysregulated miRNA‐gene network in OV tumors was constructed by Cytoscape. In the next step, co‐expression and protein‐protein interaction networks were made using GEPIA and STRING databases. Moreover, the functional analysis of the hub genes was done by DAVID, KEGG, and Enrichr databases. Eventually, the regulatory network of TF‐miRNA‐gene was constructed.

Results

The potential dysregulated miRNAs‐genes network in OV tumors has been constructed, including 109 differentially expressed genes (DEGs), 25 DEmiRs, and 213 interactions. Two down‐regulated microRNAs, miR‐660‐3p and hsa‐miR‐4510, have the most interactions with up‐expressed oncogenic DEGs. CDK1, PLK1, CCNB1, CCNA2, and EZH2 are involved in protein module, which show significant overexpression in OV tumors according to The Cancer Genome Atlas (TCGA) data. EZH2 shows amplification in OV tumors with remarkable percentage. The transcription factors TFAP2C and GATA4 have the pivotal regulatory functions in oncotranscriptomic profile of OV tumors.

Conclusion

In current study, we have collected and integrated different data to uncover the complex molecular interactions and oncomechanisms in OV tumors. The DEmiRs‐DEGs and TF‐miRNA‐gene networks reveal the potential interactions that could be a significant piece of the OV onco‐puzzle.

Phosphate Transport in Epithelial and Nonepithelial Tissue

Phosphate is an essential nutrient for life and is a critical component of bone formation, a major signaling molecule, and structural component of cell walls. Phosphate is also a component of high-energy compounds (i.e., AMP, ADP, and ATP) and essential for nucleic acid helical structure (i.e., RNA and DNA). Phosphate plays a central role in the process of mineralization, normal serum levels being associated with appropriate bone mineralization, while high and low serum levels are associated with soft tissue calcification. The serum concentration of phosphate and the total body content of phosphate are highly regulated, a process that is accomplished by the coordinated effort of two families of sodium-dependent transporter proteins. The three isoforms of the SLC34 family (SLC34A1-A3) show very restricted tissue expression and regulate intestinal absorption and renal excretion of phosphate. SLC34A2 also regulates the phosphate concentration in multiple lumen fluids including milk, saliva, pancreatic fluid, and surfactant. Both isoforms of the SLC20 family exhibit ubiquitous expression (with some variation as to which one or both are expressed), are regulated by ambient phosphate, and likely serve the phosphate needs of the individual cell. These proteins exhibit similarities to phosphate transporters in nonmammalian organisms. The proteins are nonredundant as mutations in each yield unique clinical presentations. Further research is essential to understand the function, regulation, and coordination of the various phosphate transporters, both the ones described in this review and the phosphate transporters involved in intracellular transport.

LncRNA SNHG6 promotes the migration, invasion, and epithelial-mesenchymal transition of colorectal cancer cells by miR-26a/EZH2 axis

Objective: Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Small nucleolar RNA host gene 6 (SNHG6) was reported to function as an oncogene in a number of cancers. Here, we aimed to further explore the roles and molecular mechanism of SNHG6 in CRC metastasis.

Methods: The expression levels of SNHG6, miR-26a, and enhancer of zeste homolog 2 (EZH2) mRNA were assessed by quantification real-time PCR in CRC tissues and cell lines. Western blot analysis was performed to determine the levels of E-cadherin, Snail, Vimentin, N-cadherin, and EZH2. Cell migration and invasion capacities were detected by transwell assay. Dual-luciferase reporter assay or RNA Immunoprecipitation assay was employed to verify the interaction between SNHG6 and miR-26a, or EZH2 and miR-26a.

Results: Our data indicated that SNHG6 and EZH2 mRNA were upregulated, and miR-26a was downregulated in CRC tissues and cell lines. SNHG6 knockdown suppressed the migration, invasion, and epithelial-mesenchymal transition (EMT) of CRC cells. Moreover, SNHG6 binded to miR-26a and repressed miR-26a expression. EZH2 was a direct target of miR-26a, and it was regulated by SNHG6/miR-26a. MiR-26a inhibitor undermined the effect of SNHG6 knockdown on cell migration, invasion, and EMT. Additionally, EZH2 antagonized the effect of miR-26a on cell migration, invasion, and EMT in CRC cells.

Conclusion: SNHG6 knockdown suppressed cell migration, invasion, and EMT at least partly by sponging miR-26a and regulating EZH2 expression in CRC cells, providing a strategy for blocking CRC metastasis.

SLC34A2 promotes neuroblastoma cell stemness via enhancement of miR-25/Gsk3β-mediated activation of Wnt/β-catenin signaling

Cancer stem cells contribute to cancer progression, but the mechanisms underlying neuroblastoma stem cell development are unclear. Here, we examined the roles of the transcription factor SLC34A2 in regulating the stemness of neuroblastoma cells. We found that SLC34A2 expression was negatively correlated with the overall survival and relapse‐free survival probability of neuroblastoma patients. Additionally, SLC34A2 expression was observed to be remarkably increased in spheroids derived from neuroblastoma cells. Knockdown of SLC34A2 attenuated the expression of stemness markers and spheroid formation capacity of neuroblastoma cell‐derived spheroids, and overexpression of SLC34A2 exerted the opposite effects in neuroblastoma cells. Mechanistically, SLC34A2 was found to directly bind to the promoter of MIR25, which targets glycogen synthesis kinase 3β (Gsk3β), an antagonist of Wnt signaling. Transfection of miR‐25 inhibitor or a Gsk3β overexpression plasmid attenuated the effects of SLC34A2 overexpression on the stemness of neuroblastoma cells. Our results demonstrate that miR‐25/Gsk3β‐mediated activation of Wnt signaling is responsible for SLC34A2‐induced enhancement of neuroblastoma cell stemness.

EZH2, HIF-1, and Their Inhibitors: An Overview on Pediatric Cancers

During the past decades, several discoveries have established the role of epigenetic modifications and cellular microenvironment in tumor growth and progression. One of the main representatives concerning epigenetic modification is the polycomb group (PcG). It is composed of different highly conserved epigenetic effector proteins preserving, through several post-translational modifications of histones, the silenced state of the genes implicated in a wide range of central biological events such as development, stem cell formation, and tumor progression. Proteins of the PcG can be divided in polycomb repressive complexes (PRCs): PRC1 and PRC2. In particular, enhancer of zeste homolog 2 (EZH2), the catalytic core subunit of PRC2, acts as an epigenetic silencer of many tumor suppressor genes through the trimethylation of lysine 27 on histone H3, an essential binding site for DNA methyl transferases and histone deacetylases. A growing number of data suggests that overexpression of EZH2 associates with progression and poor outcome in a large number of cancer cases. Hypoxia inducible factor (HIF) is an important transcription factor involved in modulating cellular response to the microenvironment by promoting and regulating tumor development such as angiogenesis, inflammation, metabolic reprogramming, invasion, and metastatic fate. The HIF complex is represented by different subunits (α and β) acting together and promoting the expression of vascular endothelial growth factor (VEGF), hexokinase II (HKII), receptor for advanced glycation end products (RAGE), carbonic anhydrase (CA), etc., after binding to the hypoxia-response element (HRE) binding site on the DNA. In this review, we will try to connect these two players by detailing the following: (i) the activity and influence of these two important regulators of cancer progression in particular for what concerns pediatric tumors, (ii) the possible correlation between them, and (iii) the feasibility and efficiency to contrast them using several inhibitors.