KMT2A promotes melanoma cell growth by targeting hTERT signaling pathway

KMT2A facilitates the epithelial-to-mesenchymal transition and the progression of ovarian cancer

Epithelial-mesenchymal transition (EMT) plays critical roles in cancer progression and metastasis. Thus, the exploration of the molecular mechanism regulating EMT would provide potential opportunities for the therapy of metastatic ovarian cancer (OC). Herein, we investigated the putative role of KMT2A in modulating EMT and metastasis in OC. The expression of KMT2A in OC was detected by Western blot and immunohistochemistry and its relationship with clinicopathological factors was analyzed. The effect of KMT2A on the biological behavior of OC cells was examined. Moreover, the expressions of EMT-associated proteins were detected in vivo and vitro by Western blot, immunofluorescence, and immunohistochemistry. KMT2A was highly expressed in OC cell lines and tissues and was positively correlated with advanced International Federation of Gynecology and Obstetrics (FIGO) stage, pathological grade, and metastasis. KMT2A overexpression was correlated with poor prognosis. Suppression of KMT2A inhibited OC cells proliferation, migration, and invasion and induced their apoptosis in vitro and vivo. In contrast, the ectopic expression of KMT2A had the opposite effects. Furthermore, KMT2A knockdown inhibited TGF-β-induced EMT in OC and reduced the phosphorylation levels of Smad2. Taken together, these observations demonstrate that KMT2A could promote the malignant behavior of OC by activating TGF-β/Smad signaling pathway and may be a potential prognostic biomarker and therapeutic target for OC.

KMT2A degradation is observed in decitabine-responsive acute lymphoblastic leukemia cells

Hypermethylation of tumor suppressor genes is a hallmark of leukemia. The hypomethylating agent decitabine covalently binds, and degrades DNA (cytosine-5)-methyltransferase 1 (DNMT1). Structural similarities within DNA-binding domains of DNMT1, and the leukemic driver histone-lysine N-methyltransferase 2A (KMT2A) suggest that decitabine might also affect the latter. In acute lymphoblastic leukemia (ALL) cell lines, and xenograft models, we observed increased DNMT1, and KMT2A expression in response to decitabine-induced demethylation. Strikingly, KMT2A protein expression was diminished in all cell lines that experienced DNMT1 degradation. Moreover, only cells with reduced KMT2A protein levels showed biological effects following decitabine treatment. KMT2A wild-type, and rearranged cells were locked in G2 and G1 cell cycle phases, respectively, likely due to p27/p16 activation. Primary sample gene expression profiling confirmed different patterns between KMT2A wild-type, and translocated cells. This newly discovered decitabine mode of action via KMT2A degradation evokes anti-leukemic activity in adult ALL cells, and can act synergistically with menin inhibition. Following the successful clinical implementation of decitabine for acute myeloid leukemia, the drug should be considered a potential promising addition to the therapeutic portfolio for ALL as well.

An integrated approach identifies the molecular underpinnings of murine anterior visceral endoderm migration

The anterior visceral endoderm (AVE) differs from the surrounding visceral endoderm (VE) in its migratory behavior and ability to restrict primitive streak formation to the opposite side of the mouse embryo. To characterize the molecular bases for the unique properties of the AVE, we combined single-cell RNA sequencing of the VE prior to and during AVE migration with phosphoproteomics, high-resolution live-imaging, and short-term lineage labeling and intervention. This identified the transient nature of the AVE with attenuation of "anteriorizing" gene expression as cells migrate and the emergence of heterogeneities in transcriptional states relative to the AVE's position. Using cell communication analysis, we identified the requirement of semaphorin signaling for normal AVE migration. Lattice light-sheet microscopy showed that Sema6D mutants have abnormalities in basal projections and migration speed. These findings point to a tight coupling between transcriptional state and position of the AVE and identify molecular controllers of AVE migration.

DDB2 promotes melanoma cell growth by transcriptionally regulating the expression of KMT2A and predicts a poor prognosis

Identification of potential key targets of melanoma, a fatal skin malignancy, is critical to the development of new cancer therapies. Lysine methyltransferase 2A (KMT2A) promotes melanoma growth by activating the human telomerase reverse transcriptase (hTERT) signaling pathway; however, the exact mechanism remains elusive. This study aimed to reveal new molecular targets that regulate KMT2A expression and melanoma growth. Using biotin-streptavidin-agarose pull-down and proteomics, we identified Damage-specific DNA-binding protein 2 (DDB2) as a KMT2A promoter-binding protein in melanoma cells and validated its role as a regulator of KMT2A/hTERT signaling. DDB2 knockdown inhibited the expression of KMT2A and hTERT and inhibited the growth of melanoma cells in vitro. Conversely, overexpression of DDB2 activated the expression of KMT2A and promoted the growth of melanoma cells. Additionally, we demonstrated that DDB2 expression was higher in tumor tissues of patients with melanoma than in corresponding normal tissues and was positively correlated with KMT2A expression. Kaplan-Meier analysis showed a poor prognosis in patients with high levels of DDB2 and KMT2A. Overall, our data suggest that DDB2 promotes melanoma cell growth through the transcriptional regulation of KMT2A expression and predicts poor prognosis. Therefore, targeting DDB2 may regulate the effects of KMT2A on melanoma growth and progression, providing a new potential therapeutic strategy for melanoma.

Favipiravir, an antiviral drug, in combination with tamoxifen exerts synergistic effect in tamoxifen-resistant breast cancer cells via hTERT inhibition

Tamoxifen (TAM) is one of the most successful treatments for breast cancer; however, TAM resistance continues to be a significant barrier. TAM resistance has been reported to be associated with increased expression of human telomerase reverse transcriptase (hTERT). This enzyme shares structural similarity with RNA-dependent RNA polymerase (RdRp) enzyme of RNA viruses, suggesting that RdRp inhibitors may also inhibit hTERT. Favipiravir (FAV) is an antiviral drug that inhibits RdRp of RNA viruses. Thus, we propose that FAV may also elicit an antitumor effect by suppressing hTERT. This study aimed to investigate the effect of FAV and TAM on TAM-resistant breast cancer (TAMR-1). The cell viabilities were determined. The levels of CDK1/ hTERT, in addition to regulators of hTERT-targeted signaling pathways were measured. Apoptosis, migration, and cell cycle distribution were also determined. Our data revealed that the combination of TAM and FAV suppressed cell proliferation synergistically (CI < 1) and resulted in a significant change in cell migration and apoptosis. Indeed, this was associated with reduced levels of hTERT and CDK1 and shift in the cell cycle distribution. Our findings suggest that the TAM/FAV combination exhibits synergistic effects against TAMR-1 human breast cancer cells by targeting hTERT.

KMT2A is targeted by miR-361-3p and modulates leukemia cell's abilities to proliferate, migrate and invade

OBJECTIVE

The lives and safety of humans are significantly threatened by acute myeloid leukemia (AML), which is proven to be the most prevalent acute leukemia. This work is therefore intended to investigate and analyze the expressions of miR-361-3p and Histone Lysine Methyltransferase 2A (KMT2A) in tissues and cell lines of AML and identify an advanced and novel target for the therapy of AML.

METHODS

The qRT-PCR and western blot assays were conducted to find expressions of miR-361-3p/KMT2A in AML PB and cell lines. After then, tests using CCK-8 and EdU were run to see how KMT2A affected the growth of AML cells. Transwell migration and invasion assay was conducted to evaluate KMT2A's contribution to the migration and invasion of AML cells. ENCORI and miRWalk predicted the association between KMT2A and miR-361-3p, and the dual-luciferase reporter experiment verified it. Furthermore, rescue studies were used to ascertain how KMT2A affected the miR-361-3p-regulated AML cells' abilities to proliferate, migrate, and invade.

RESULTS

miR-361-3p was poorly expressed while KMT2A was abundantly expressed. Additionally, KMT2A downregulation prevented AML cells from proliferating. PCNA and Ki-67 protein levels fell when KMT2A was silent. Furthermore, AML cells' motility, invasion, and metastasis were inhibited by low KMT2A expression. KMT2A was also identified as a direct target of miR-361-3p and negatively correlated with miR-361-3p. Finally, the over-expression of KMT2A partially reversed the inhibitory effects of up-regulation of miR-361-3p.

CONCLUSION

A potential therapeutic candidate target for the treatment of AML may be miR-361-3p/KMT2A.

The Relevance of Telomerase and Telomere-Associated Proteins in B-Acute Lymphoblastic Leukemia

Telomeres and telomerase are closely linked to uncontrolled cellular proliferation, immortalization and carcinogenesis. Telomerase has been largely studied in the context of cancer, including leukemias. Deregulation of human telomerase gene hTERT is a well-established step in leukemia development. B-acute lymphoblastic leukemia (B-ALL) recovery rates exceed 90% in children; however, the relapse rate is around 20% among treated patients, and 10% of these are still incurable. This review highlights the biological and clinical relevance of telomerase for B-ALL and the implications of its canonical and non-canonical action on signaling pathways in the context of disease and treatment. The physiological role of telomerase in lymphocytes makes the study of its biomarker potential a great challenge. Nevertheless, many works have demonstrated that high telomerase activity or hTERT expression, as well as short telomeres, correlate with poor prognosis in B-ALL. Telomerase and related proteins have been proven to be promising pharmacological targets. Likewise, combined therapy with telomerase inhibitors may turn out to be an alternative strategy for B-ALL.

Role of histone methylation in skin cancers: Histone methylation-modifying enzymes as a new class of targets for skin cancer treatment

Histone methylation, one of the most prominent epigenetic modifications, plays a vital role in gene transcription, and aberrant histone methylation levels cause tumorigenesis. Histone methylation is a reversible enzyme-dependent reaction, and histone methyltransferases and demethylases are involved in this reaction. This review addresses the biological and clinical relevance of these histone methylation-modifying enzymes for skin cancer. In particular, the roles of histone lysine methyltransferases, histone arginine methyltransferase, lysine-specific demethylases, and JmjC demethylases in skin cancer are discussed in detail. In addition, we summarize the efficacy of several epigenetic inhibitors targeting histone methylation-modifying enzymes in cutaneous cancers, such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. In conclusion, we propose histone methylation-modifying enzymes as novel targets for next-generation pharmaceuticals in the treatment of skin cancers and further provide a rationale for the development of epigenetic drugs (epidrugs) that target specific histone methylases/demethylases in cutaneous tumors.

Bromodomain (BrD) Family Members as Regulators of Cancer Stemness-A Comprehensive Review

Epigenetic mechanisms involving DNA methylation and chromatin modifications have emerged as critical facilitators of cancer heterogeneity, substantially affecting cancer development and progression, modulating cell phenotypes, and enhancing or inhibiting cancer cell malignant properties. Not surprisingly, considering the importance of epigenetic regulators in normal stem cell maintenance, many chromatin-related proteins are essential to maintaining the cancer stem cell (CSC)-like state. With increased tumor-initiating capacities and self-renewal potential, CSCs promote tumor growth, provide therapy resistance, spread tumors, and facilitate tumor relapse after treatment. In this review, we characterized the epigenetic mechanisms that regulate the acquisition and maintenance of cancer stemness concerning selected epigenetic factors belonging to the Bromodomain (BrD) family of proteins. An increasing number of BrD proteins reinforce cancer stemness, supporting the maintenance of the cancer stem cell population in vitro and in vivo via the utilization of distinct mechanisms. As bromodomain possesses high druggable potential, specific BrD proteins might become novel therapeutic targets in cancers exhibiting de-differentiated tumor characteristics.

PIK3R2 predicts poor outcomes for patients with melanoma and contributes to the malignant progression via PI3K/AKT/NF-κB axis

BACKGROUND

Melanoma is an aggressive form of skin cancer worldwide. Phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) exerts carcinogenic roles in various tumors. So far, the function and mechanism of PIK3R2 in melanoma are not been fully clarified.

OBJECTIVE

We aimed to clarify the role of PIK3R2 in melanoma.

METHODS

PIK3R2 expressions in melanoma clinical tissues and melanoma cells were measured using quantitative real-time PCR and Western blot. In addition, PIK3R2 expressions in different tumor stages of melanoma were determined by immunohistochemistry assay. Meanwhile, PIK3R2 function was evaluated using loss or gain-of-function assays, Cell Counting Kit-8 assay, flow cytometry, and Transwell analysis. Furthermore, PIK3R2 mechanism in melanoma was assessed by a series of rescue experiments.

RESULTS

PIK3R2 was highly expressed in melanoma tissues and cells, and PIK3R2 expressions were the highest in Stage IV. Functionally, PIK3R2 knockdown repressed melanoma cell proliferation, invasion, epithelial-mesenchymal transition, and facilitated cell apoptosis. Also, PIK3R2 overexpression produced an opposite trend. Mechanistically, PIK3R2 facilitated melanoma progression by activating PI3K/AKT/NF-κB pathway. Furthermore, PIK3R2 knockdown restrained the melanoma tumor growth in vivo.

CONCLUSIONS

PIK3R2 aggravated melanoma by activating PI3K/AKT/NF-κB pathway, prompting that PIK3R2 might be a therapeutic target for melanoma.

Inhibiting the growth of melanoma cells via hTERT gene editing using CRISPR-dCas9-dnmt3a system

CRISPR-Cas9 gene-editing technology has pushed the boundaries of genetic modification. The principle of this method is based on the purposeful defense system of DNA degradation and will be one of the most powerful instruments for gene editing shortly. The purpose of this study was to evaluate the capability of this approach to manage melanoma cells. The present study used EF1a-hsaCas9-U6-gRNA as a hybrid vector of sgRNA and Cas9 for the transfection of A-375 melanoma cells. Transfection efficiency was enhanced by examining the two concentrations of 4 and 8 µg/mL of hexadimethrine bromide (trade name Polybrene). The existence of Cas9 in transfected cells was detected by flow cytometry. The expression level of the metabisulfite-modified hTERT gene was measured by real-time PCR technique. The presence of telomerase in cells was determined by flow cytometry and western blotting analysis. The hTERT gene promoter methylation was also evaluated by HRM assay. Finally, the induction of apoptosis in transfected A375 cells was assessed using flow cytometry. The results showed that the presence of gRNA significantly increased the transfection efficiency (up to about 7.75 times higher). The hTERT expression levels in A-375 cells were significantly decreased at different concentrations of Polybrene (in a dose-dependent manner) and various amounts of transfection (P < 0.05). The expression of hTERT in basal cells was not significantly different from the group transfected without gRNA (P˃0.05) but was significantly higher than the group transfected with gRNA (P < 0.05). The results of flow cytometry and western blotting analysis showed a decrease in hTERT level compared to cells transfected without gRNA as well as basal cells. The methylation of hTERT gene promoter in the cells transfected with gRNA at a concentration of 80 μg/mL in the presence of both 4 μg/mL and 8 μg/mL of Polybrene was significantly increased compared to those transfected without sRNA (P < 0.05). The flow cytometry results indicated no significant difference in the induction of apoptosis in the transfected cells compared to the basal cells (P < 0.05). Evidence suggests that the designed CRISPR/Cas9 system reduces the expression of the hTERT gene and telomerase presence, thereby inhibiting the growth of melanoma cells.

Targeting matrix metallopeptidase 2 by hydroxyurea selectively kills acute myeloid mixed-lineage leukemia

Oncogene-induced tumorigenesis results in the variation of epigenetic modifications, and in addition to promoting cell immortalization, cancer cells undergo more intense cellular stress than normal cells and depend on other support genes for survival. Chromosomal translocations of mixed-lineage leukemia (MLL) induce aggressive leukemias with an inferior prognosis. Unfortunately, most MLL-rearranged (MLL-r) leukemias are resistant to conventional chemotherapies. Here, we showed that hydroxyurea (HU) could kill MLL-r acute myeloid leukemia (AML) cells through the necroptosis process. HU target these cells by matrix metallopeptidase 2 (MMP2) deficiency rather than subordinate ribonucleotide reductase regulatory subunit M2 (RRM2) inhibition, where MLL directly regulates MMP2 expression and is decreased in most MLL-r AMLs. Moreover, iron chelation of HU is also indispensable for inducing cell stress, and MMP2 is the support factor to protect cells from death. Our preliminary study indicates that MMP2 might play a role in the nonsense-mediated mRNA decay pathway that prevents activation of unfolding protein response under innocuous endoplasmic reticulum stress. Hence, these results reveal a possible strategy of HU application in MLL-r AML treatment and shed new light upon HU repurposing.

The role of KMT2 gene in human tumors

Histone methylation plays a crucial role in the regulation of gene transcriptional expression, and aberration of methylation-modifying enzyme genes can lead to a variety of genetic diseases, including human cancers. The histone modified protein KMT2 (lysin methyltransferase) family are involved in cell proliferation, growth, development and differentiation through regulating gene expression, and are closely related with many blood cancers and solid tumors. In recent years, several studies have shown that mutations in the KMT2 gene occur frequently in a variety of human cancers and the mutation status of the KMT2 gene may be correlated with the occurrence, development and prognosis of some tumors. Research uncovering the clinical characteristics and molecular mechanisms of KMT2 mutation in human tumors will be helpful for early diagnosis and prognosis of tumors as well as drug development for targeted therapies.

MiR-138-5p Suppresses Cell Growth and Migration in Melanoma by Targeting Telomerase Reverse Transcriptase

Recent evidence suggests the existence of a miRNA regulatory network involving human telomerase reverse transcriptase gene (hTERT), with miR-138-5p playing a central role in many types of cancers. However, little is known about the regulation of hTERT expression by microRNA (miRNAs) in melanocytic tumors. Here, we investigated the effects of miR-138-5p in hTERT regulation in melanoma cells lines. In vitro studies demonstrated higher miR-138-5p and lower hTERT messenger RNA (mRNA) expression in human epidermal melanocytes, compared with melanoma cell lines (A2058, A375, SK-MEL-28) by quantitative polymerase chain reaction (qPCR) observing a negative correlation between them. A2058 melanoma cells were selected to be transfected with miR-138-5p mimic or inhibitor. Using luciferase assay, hTERT was identified as a direct target of this miRNA. Overexpression of miR-138-5p detected by Western blot revealed a decrease in hTERT protein expression (p = 0.012), and qPCR showed a reduction in telomerase activity (p < 0.001). Moreover, suppressions in cell growth (p = 0.035) and migration abilities (p = 0.015) were observed in A2058-transfected cells using thiazolyl blue tetrazolium bromide and flow cytometry, respectively. This study identifies miR-138-5p as a crucial tumor suppressor miRNA involved in telomerase regulation. Targeting it as a combination therapy with immunotherapy or targeted therapies could be used in advanced melanoma treatment; however, more preclinical studies are necessary.

Pseudogene RPL32P3 regulates the blood-tumor barrier permeability via the YBX2/HNF4G axis

The existence of the blood–tumor barrier (BTB) severely hinders the transport of anti-tumor drugs to brain tumor tissues. Selectively opening BTB is of great significance to improve the chemotherapy effect of glioma. Pseudogenes have been recognized as important regulators in various biologic processes. In this study, we identified that ribosomal protein L32 pseudogene 3 (RPL32P3) was highly expressed in glioma-exposed endothelial cells (GECs). Knockdown of RPL32P3 decreased the expression of tight junction-related proteins (TJPs) and increased BTB permeability. Subsequent analysis of the underlying mechanism indicated that RPL32P3 recruited lysine methyltransferase 2 A (KMT2A) to the Y-box binding protein 2 (YBX2) promoter region and mediated H3K4me3 to promote YBX2 transcription. Highly expressed YBX2 bound and stabilized hepatocyte nuclear factor 4 gamma (HNF4G) mRNA. Highly expressed HNF4G directly bound to the promoters of TJPs ZO-1, occludin and claudin-5 to promote their transcriptional activities and regulated BTB permeability. The simultaneous knockdown of RPL32P3, YBX2, and HNF4G combined with doxorubicin (DOX) increased the apoptosis of glioma cells. In conclusion, the current study indicated that RPL32P3 knockdown increased BTB permeability through the YBX2/HNF4G pathway. These findings may provide new targets for the comprehensive treatment of glioma.

Pro-angiogenic effect of PC-3 exosomes in endothelial cells in vitro

The progression to a castration-resistant prostate cancer can occur after treatment with androgen deprivation therapy, resulting in poor prognosis and ineffective therapy response. Hormone dependence transition has been associated with increased tumor vascularization. Considering that exosomes are important components in communication between tumor cells and the microenvironment, we examined the angiogenic potential of exosomes released from Pca cell lines with distinctive profiles of androgen response through exosomes isolation, microscopy and uptake, functional assays follow up by microarray, RT-qPCR and bioinformatics analysis. HUVEC cells treated with PC-3 exosomes (androgen independent) showed increased invasion and tube formation ability. In order to identify microRNAs (miRNAs) related to the angiogenic response, the characterization of exosomal miRNA profile was performed. As result we suggest that the miR-27a-3p could be involved in the pro-angiogenic effect of PC-3 exosomes.

Alcohol-abuse drug disulfiram targets pediatric glioma via MLL degradation

Pediatric gliomas comprise a broad range of brain tumors derived from glial cells. While high-grade gliomas are often resistant to therapy and associated with a poor outcome, children with low-grade gliomas face a better prognosis. However, the treatment of low-grade gliomas is often associated with severe long-term adverse effects. This shows that there is a strong need for improved treatment approaches. Here, we highlight the potential for repurposing disulfiram to treat pediatric gliomas. Disulfiram is a drug used to support the treatment of chronic alcoholism and was found to be effective against diverse cancer types in preclinical studies. Our results show that disulfiram efficiently kills pediatric glioma cell lines as well as patient-derived glioma stem cells. We propose a novel mechanism of action to explain disulfiram’s anti-oncogenic activities by providing evidence that disulfiram induces the degradation of the oncoprotein MLL. Our results further reveal that disulfiram treatment and MLL downregulation induce similar responses at the level of histone modifications and gene expression, further strengthening that MLL is a key target of the drug and explaining its anti-oncogenic properties.

Statistical and bioinformatic analysis of hemimethylation patterns in non-small cell lung cancer

Background

DNA methylation is an epigenetic event involving the addition of a methyl-group to a cytosine-guanine base pair (i.e., CpG site). It is associated with different cancers. Our research focuses on studying non-small cell lung cancer hemimethylation, which refers to methylation occurring on only one of the two DNA strands. Many studies often assume that methylation occurs on both DNA strands at a CpG site. However, recent publications show the existence of hemimethylation and its significant impact. Therefore, it is important to identify cancer hemimethylation patterns.

Methods

In this paper, we use the Wilcoxon signed rank test to identify hemimethylated CpG sites based on publicly available non-small cell lung cancer methylation sequencing data. We then identify two types of hemimethylated CpG clusters, regular and polarity clusters, and genes with large numbers of hemimethylated sites. Highly hemimethylated genes are then studied for their biological interactions using available bioinformatics tools.

Results

In this paper, we have conducted the first-ever investigation of hemimethylation in lung cancer. Our results show that hemimethylation does exist in lung cells either as singletons or clusters. Most clusters contain only two or three CpG sites. Polarity clusters are much shorter than regular clusters and appear less frequently. The majority of clusters found in tumor samples have no overlap with clusters found in normal samples, and vice versa. Several genes that are known to be associated with cancer are hemimethylated differently between the cancerous and normal samples. Furthermore, highly hemimethylated genes exhibit many different interactions with other genes that may be associated with cancer. Hemimethylation has diverse patterns and frequencies that are comparable between normal and tumorous cells. Therefore, hemimethylation may be related to both normal and tumor cell development.

Conclusions

Our research has identified CpG clusters and genes that are hemimethylated in normal and lung tumor samples. Due to the potential impact of hemimethylation on gene expression and cell function, these clusters and genes may be important to advance our understanding of the development and progression of non-small cell lung cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07990-7.

A comprehensive molecular characterization of the 8q22.2 region reveals the prognostic relevance of OSR2 mRNA in muscle invasive bladder cancer

Technological advances in molecular profiling have enabled the comprehensive identification of common regions of gene amplification on chromosomes (amplicons) in muscle invasive bladder cancer (MIBC). One such region is 8q22.2, which is largely unexplored in MIBC and could harbor genes with potential for outcome prediction or targeted therapy. To investigate the prognostic role of 8q22.2 and to compare different amplicon definitions, an in-silico analysis of 357 patients from The Cancer Genome Atlas, who underwent radical cystectomy for MIBC, was performed. Amplicons were generated using the GISTIC2.0 algorithm for copy number alterations (DNA_Amplicon) and z-score normalization for mRNA gene overexpression (RNA_Amplicon). Kaplan-Meier survival analysis, univariable, and multivariable Cox proportional hazard ratios were used to relate amplicons, genes, and clinical parameters to overall (OS) and disease-free survival (DFS). Analyses of the biological functions of 8q22.2 genes and genomic events in MIBC were performed to identify potential targets. Genes with prognostic significance from the in silico analysis were validated using RT-qPCR of MIBC tumor samples (n = 46). High 8q22.2 mRNA expression (RNA-AMP) was associated with lymph node metastases. Furthermore, 8q22.2 DNA and RNA amplified patients were more likely to show a luminal subtype (DNA_Amplicon_core: p = 0.029; RNA_Amplicon_core: p = 0.01). Overexpression of the 8q22.2 gene OSR2 predicted shortened DFS in univariable (HR [CI] 1.97 [1.2; 3.22]; p = 0.01) and multivariable in silico analysis (HR [CI] 1.91 [1.15; 3.16]; p = 0.01) and decreased OS (HR [CI] 6.25 [1.37; 28.38]; p = 0.0177) in RT-qPCR data analysis. Alterations in different levels of the 8q22.2 region are associated with manifestation of different clinical characteristics in MIBC. An in-depth comprehensive molecular characterization of genomic regions involved in cancer should include multiple genetic levels, such as DNA copy number alterations and mRNA gene expression, and could lead to a better molecular understanding. In this study, OSR2 is identified as a potential biomarker for survival prognosis.

Gene co-expression and histone modification signatures are associated with melanoma progression, epithelial-to-mesenchymal transition, and metastasis

BACKGROUND

We have previously developed a murine cellular system that models the transformation from melanocytes to metastatic melanoma cells. This model was established by cycles of anchorage impediment of melanocytes and consists of four cell lines: differentiated melanocytes (melan-a), pre-malignant melanocytes (4C), malignant (4C11-), and metastasis-prone (4C11+) melanoma cells. Here, we searched for transcriptional and epigenetic signatures associated with melanoma progression and metastasis by performing a gene co-expression analysis of transcriptome data and a mass-spectrometry-based profiling of histone modifications in this model.

RESULTS

Eighteen modules of co-expressed genes were identified, and some of them were associated with melanoma progression, epithelial-to-mesenchymal transition (EMT), and metastasis. The genes in these modules participate in biological processes like focal adhesion, cell migration, extracellular matrix organization, endocytosis, cell cycle, DNA repair, protein ubiquitination, and autophagy. Modules and hub signatures related to EMT and metastasis (turquoise, green yellow, and yellow) were significantly enriched in genes associated to patient survival in two independent melanoma cohorts (TCGA and Leeds), suggesting they could be sources of novel prognostic biomarkers. Clusters of histone modifications were also linked to melanoma progression, EMT, and metastasis. Reduced levels of H4K5ac and H4K8ac marks were seen in the pre-malignant and tumorigenic cell lines, whereas the methylation patterns of H3K4, H3K56, and H4K20 were related to EMT. Moreover, the metastatic 4C11+ cell line showed higher H3K9me2 and H3K36me3 methylation, lower H3K18me1, H3K23me1, H3K79me2, and H3K36me2 marks and, in agreement, downregulation of the H3K36me2 methyltransferase Nsd1.

CONCLUSIONS

We uncovered transcriptional and histone modification signatures that may be molecular events driving melanoma progression and metastasis, which can aid in the identification of novel prognostic genes and drug targets for treating the disease.

KMT2C, a histone methyltransferase, is mutated in a family segregating non-syndromic primary failure of tooth eruption

Primary failure of tooth eruption (PFE) is a rare odontogenic defect and is characterized by failure of eruption of one or more permanent teeth. The aim of the study is to identify the genetic defect in a family with seven affected individuals segregating autosomal dominant non-syndromic PFE. Whole genome single-nucleotide polymorphism (SNP) genotyping was performed. SNP genotypes were analysed by DominantMapper and multiple shared haplotypes were detected on different chromosomes. Four individuals, including three affected, were exome sequenced. Variants were annotated and data were analysed while considering candidate chromosomal regions. Initial analysis of variants obtained by whole exome sequencing identified damaging variants in C15orf40, EPB41L4A, TMEM232, KMT2C, and FBXW10 genes. Sanger sequencing of all family members confirmed segregation of splice acceptor site variant (c.1013-2 A > G) in the KMT2C gene with the phenotype. KMT2C is considered as a potential candidate gene based on segregation analysis, the absence of variant in the variation databases, the presence of variant in the shared identical by descent (IBD) region and in silico pathogenicity prediction. KMT2C is a histone methyltransferase and recently the role of another member of this family (KMT2D) has been implicated in tooth development. Moreover, protein structures of KMT2C and KMT2D are highly similar. In conclusion, we have identified that the KMT2C gene mutation causes familial non-syndromic PFE. These findings suggest the involvement of KMT2C in the physiological eruption of permanent teeth.

MicroRNA-769-5p Promotes The Growth Of Glioma Cells By Targeting Lysine Methyltransferase 2A

Background

Accumulating evidence supports the involvement of microRNAs (miRNAs) in the progression of human cancers including glioma. Recently, miR-769-5p has been reported to play a tumor suppressive role in colorectal cancer and lung cancer, whereas it exerts an oncogenic role in melanoma. However, the role of miR-769-5p and its related mechanism are poorly elucidated.

Methods

The levels of miR-769-5p in glioma tissues and adjacent non-tumor tissues were detected by qRT-PCR. In addition, the effects of miR-769-5p on cell proliferation and apoptosis were evaluated by CCK-8, EdU, colony formation and flow cytometric assays, respectively. Meanwhile, the dual-luciferase reporter assay was used to investigate the interaction of miR-769-5p and lysine methyltransferase 2A (KMT2A) in glioma.

Results

We found that miR-769-5p expression was strongly upregulated in glioma tissues and cell lines. Glioma tissues with high World Health Organization (WHO) grades had obvious higher levels of miR-769-5p compared to samples with low WHO grades. Interestingly, glioma patients highly expressing miR-769-5p showed prominent poorer survivals. Knockdown of miR-769-5p significantly suppressed cell proliferation and resulted in apoptosis in glioma cells. Additionally, miR-769-5p silencing restrained in vivo growth of glioma cells in mice. Interestingly, KMT2A was identified to be a direct target of miR-769-5p in glioma cells. The expression of KMT2A mRNA was downregulated in glioma tissues and inversely correlated with miR-769-5p level. KMT2A overexpression inhibited cell proliferation and induced the apoptosis of A172 cells. Moreover, siRNA-mediated KMT2A silencing could partially abolish miR-769-5p knockdown-induced suppressive effects on A172 cells.

Conclusion

In summary, our findings suggest that targeting miR-769-5p/KMT2A axis may be a promising therapeutic target for glioma treatment.

The prognostic significance of hTERT overexpression in cancers: A systematic review and meta-analysis

BACKGROUND

Human telomerase reverse transcriptase (hTERT) plays an important role in cancer progression. Recently, several clinical studies investigated how the overexpression of hTERT predicts the poor prognosis of solid tumors. However, the results were inconclusive, partly because of the small numbers of patients included.

METHOD

We systematically searched PubMed, Web of Science, and Embase to identify relevant studies until August 2017. Hazard ratios (HRs) with 95% confidence intervals (CIs) were used to evaluate the association of hTERT expression and survival outcomes.

RESULTS

A total of 27studies enrolling 2530 solid tumor patients were included in this meta-analysis. There were strong significant associations between hTERT overexpression and all endpoints: overall survival (OS) (HR = 1.50, 95% CI: 1.31-1.73, P = .00), disease-free survival (HR = 1.84, 95% CI: 1.38-2.46; P = .00), and recurrence-free survival (HR = 1.79, 95% CI: 1.07-2.99; P = .028). In the subgroup analysis, it was found that the overexpression of hTERT induced poor OS in lung cancer (HR = 1.51, 95% CI: 1.21-1.89; P = .00).

CONCLUSION

Our comprehensive systematic review concluded that the overexpression of hTERT was associated with poor survival in human solid tumors. hTERT may be a valuable predictive biomarker for prognosis.

WDR5 supports colon cancer cells by promoting methylation of H3K4 and suppressing DNA damage

BACKGROUND

KMT2/MLL proteins are commonly overexpressed or mutated in cancer and have been shown to support cancer maintenance. These proteins are responsible for methylating histone 3 at lysine 4 and promoting transcription and DNA synthesis; however, they are inactive outside of a multi-protein complex that requires WDR5. WDR5 has been implicated in cancer for its role in the COMPASS complex and its interaction with Myc; however, the role of WDR5 in colon cancer has not yet been elucidated.

METHODS

WDR5 expression was evaluated using RT-qPCR and western blot analysis. Cell viability and colony forming assays were utilized to evaluate the effects of WDR5 depletion or inhibition in colon cancer cells. Downstream effects of WDR5 depletion and inhibition were observed by western blot.

RESULTS

WDR5 is overexpressed in colon tumors and colon cancer cell lines at the mRNA and protein level. WDR5 depletion reduces cell viability in HCT116, LoVo, RKO, HCT15, SW480, SW620, and T84 colon cancer cells. Inhibition of the WDR5:KMT2/MLL interaction using OICR-9429 reduces cell viability in the same panel of cell lines albeit not to the same extent as RNAi-mediated WDR5 depletion. WDR5 depletion reduced H3K4Me3 and increased phosphorylation of H2AX in HCT116, SW620, and RKO colon cancer cells; however, OICR-9429 treatment did not recapitulate these effects in all cell lines potentially explaining the reduced toxicity of OICR-9429 treatment as compared to WDR5 depletion. WDR5 depletion also sensitized colon cancer cells to radiation-induced DNA damage.

CONCLUSIONS

These data demonstrate a clear role for WDR5 in colon cancer and future studies should examine its potential to serve as a therapeutic target in cancer. Additional studies are needed to fully elucidate if the requirement for WDR5 is independent of or consistent with its role within the COMPASS complex. OICR-9429 treatment was particularly toxic to SW620 and T84 colon cancer cells, two cell lines without mutations in WDR5 and KMT2/MLL proteins suggesting COMPASS complex inhibition may be particularly effective in tumors lacking KMT2 mutations. Additionally, the ability of WDR5 depletion to amplify the toxic effects of radiation presents the possibility of targeting WDR5 to sensitize cells to DNA-damaging therapies.

LncRNA OIP5-AS1 is overexpressed in undifferentiated oral tumors and integrated analysis identifies as a downstream effector of stemness-associated transcription factors

Long non-coding RNAs (lncRNAs) play an important role in the regulation of key cellular processes in early development and cancer. LncRNA Oip5-as1 facilitates stem cell self-renewal in mouse by sponging mmu-miR-7 and modulating NANOG level, yet its role in cancer is less understood. We analyzed OIP5-AS1 expression in oral tumors and in TCGA datasets. We observed overexpression of OIP5-AS1 in oral tumors (P < 0.001) and in tumors of epithelial origin from TCGA. OIP5-AS1 expression was strongly associated with undifferentiated tumors (P = 0.0038). In silico analysis showed miR-7 binding site is conserved in mouse and human OIP5-AS1. However, human NANOG 3'-UTR lost the binding site for hsa-miR-7a-3. Therefore, we screened for other miRNAs that can be sponged by OIP5-AS1 and identified six potential miRNAs and their downstream target genes. Expression analysis showed downregulation of miRNAs and upregulation of downstream target genes, particularly in undifferentiated tumors with high-level of OIP5-AS1 suggesting OIP5-AS1 could post-transcriptionally modulate the downstream target genes. Further, systematic epigenomic analysis of OIP5-AS1 promoter revealed binding motifs for MYC, NANOG and KLF4 suggesting that OIP5-AS1 could be transactivated by stemness-associated transcription factors in cancer. OIP5-AS1 overexpression in undifferentiated oral tumors may be suggestive of enhanced cancer stemness, and consequently, poor clinical outcome.

Integrative analysis of competing endogenous RNA network focusing on long noncoding RNA associated with progression of cutaneous melanoma

Cutaneous melanoma (CM) is the most malignant tumor of skin cancers because of its rapid development and high mortality rate. Long noncoding RNAs (lncRNAs), which play essential roles in the tumorigenesis and metastasis of CM and interplay with microRNAs (miRNAs) and mRNAs, are hopefully considered to be efficient biomarkers to detect deterioration during the progression of CM to improve the prognosis. Bioinformatics analysis was fully applied to predict the vital lncRNAs and the associated miRNAs and mRNAs, which eventually constructed the competing endogenous RNA (ceRNA) network to explain the RNA expression patterns in the progression of CM. Further statistical analysis emphasized the importance of these key genes, which were statistically significantly related to one or few clinical features from the ceRNA network. The results showed the lncRNAs MGC12926 and LINC00937 were verified to be strongly connected with the prognosis of CM patients.

Histone modifiers: Dynamic regulators of the cutaneous transcriptome

By regulating the accessibility of the genome, epigenetic regulators such as histone proteins and the chromatin-modifying enzymes that act upon them control gene expression. Proper regulation of this "histone code" allows for the precise control of transcriptional networks that are essential for establishing and maintaining cell fate and identity, disruption of which may drive carcinogenesis. How these dynamic epigenetic regulators contribute to both skin homeostasis and disease is only beginning to be understood. Here we provide an update of the current understanding of histone modifiers in the skin. Indeed, as one of the most innovative and rapidly expanding areas in all of medicine, it is clear that epigenome-targeting therapies hold great promise for the treatment of dermatological diseases in the coming years.