MTF2 Induces Epithelial-Mesenchymal Transition and Progression of Hepatocellular Carcinoma by Transcriptionally Activating Snail

MTF2 facilitates the advancement of osteosarcoma through mediating EZH2/SFRP1/Wnt signaling

BACKGROUND

Osteosarcoma is a soft tissue neoplasm with elevated recurrence risk and highly metastatic potential. Metal response element binding transcriptional factor 2 (MTF2) has been revealed to exert multiple activities in human tissues. The present research was conducted to explore the functions and related response mechanism of MTF2 in osteosarcoma which have not been introduced yet.

METHODS

Bioinformatics tools identified the differential MTF2 expression in osteosarcoma tissues. MTF2 expression in osteosarcoma cells was examined with Western blot. Cell Counting Kit-8 (CCK-8) assay, 5-Ethynyl-2'-deoxyuridine (EDU) staining, wound healing as well as transwell assays measured cell proliferation, migration and invasion, respectively. Flow cytometry assay detected the cellular apoptotic level. Western blot also measured the expressions of proteins associated with epithelial mesenchymal transition (EMT), apoptosis and enhancer of zeste homolog 2 (EZH2)/secreted frizzled-related protein 1 (SFRP1)/Wnt signaling. Co-immunoprecipitation (Co-IP) assay confirmed MTF2-EZH2 interaction.

RESULTS

MTF2 expression was increased in osteosarcoma tissues and cells. MTF2 interference effectively inhibited the proliferation, migration and invasion of osteosarcoma cells and promoted the cellular apoptotic rate. MTF2 directly bound to EZH2 and MTF2 silence reduced EZH2 expression, activated SFRP1 expression and blocked Wnt signaling in osteosarcoma cells. EZH2 upregulation or SFRP1 antagonist WAY-316606 partly counteracted the impacts of MTF2 down-regulation on the SFRP1/Wnt signaling and the biological phenotypes of osteosarcoma cells.

CONCLUSIONS

MTF2 might down-regulate SFRP1 to activate Wnt signaling and drive the progression of osteosarcoma via interaction with EZH2 protein.

The PRC2.1 Subcomplex Opposes G1 Progression through Regulation of CCND1 and CCND2

Progression through the G1 phase of the cell cycle is the most highly regulated step in cellular division. We employed a chemogenomics approach to discover novel cellular networks that regulate cell cycle progression. This approach uncovered functional clusters of genes that altered sensitivity of cells to inhibitors of the G1/S transition. Mutation of components of the Polycomb Repressor Complex 2 rescued growth inhibition caused by the CDK4/6 inhibitor palbociclib, but not to inhibitors of S phase or mitosis. In addition to its core catalytic subunits, mutation of the PRC2.1 accessory protein MTF2, but not the PRC2.2 protein JARID2, rendered cells resistant to palbociclib treatment. We found that PRC2.1 (MTF2), but not PRC2.2 (JARID2), was critical for promoting H3K27me3 deposition at CpG islands genome-wide and in promoters. This included the CpG islands in the promoter of the CDK4/6 cyclins CCND1 and CCND2, and loss of MTF2 lead to upregulation of both CCND1 and CCND2. Our results demonstrate a role for PRC2.1, but not PRC2.2, in promoting G1 progression.

Tissue-Specific Tumour Suppressor and Oncogenic Activities of the Polycomb-like Protein MTF2

The Polycomb repressive complex 2 (PRC2) is a conserved chromatin-remodelling complex that catalyses the trimethylation of histone H3 lysine 27 (H3K27me3), a mark associated with gene silencing. PRC2 regulates chromatin structure and gene expression during organismal and tissue development and tissue homeostasis in the adult. PRC2 core subunits are associated with various accessory proteins that modulate its function and recruitment to target genes. The multimeric composition of accessory proteins results in two distinct variant complexes of PRC2, PRC2.1 and PRC2.2. Metal response element-binding transcription factor 2 (MTF2) is one of the Polycomb-like proteins (PCLs) that forms the PRC2.1 complex. MTF2 is highly conserved, and as an accessory subunit of PRC2, it has important roles in embryonic stem cell self-renewal and differentiation, development, and cancer progression. Here, we review the impact of MTF2 in PRC2 complex assembly, catalytic activity, and spatiotemporal function. The emerging paradoxical evidence suggesting that MTF2 has divergent roles as either a tumour suppressor or an oncogene in different tissues merits further investigations. Altogether, our review illuminates the context-dependent roles of MTF2 in Polycomb group (PcG) protein-mediated epigenetic regulation. Its impact on disease paves the way for a deeper understanding of epigenetic regulation and novel therapeutic strategies.

Polycomb-like Proteins in Gene Regulation and Cancer

Polycomb-like proteins (PCLs) are a crucial group of proteins associated with the Polycomb repressive complex 2 (PRC2) and are responsible for setting up the PRC2.1 subcomplex. In the vertebrate system, three homologous PCLs exist: PHF1 (PCL1), MTF2 (PCL2), and PHF19 (PCL3). Although the PCLs share a similar domain composition, they differ significantly in their primary sequence. PCLs play a critical role in targeting PRC2.1 to its genomic targets and regulating the functionality of PRC2. However, they also have PRC2-independent functions. In addition to their physiological roles, their dysregulation has been associated with various human cancers. In this review, we summarize the current understanding of the molecular mechanisms of the PCLs and how alterations in their functionality contribute to cancer development. We particularly highlight the nonoverlapping and partially opposing roles of the three PCLs in human cancer. Our review provides important insights into the biological significance of the PCLs and their potential as therapeutic targets for cancer treatment.

Comprehensive Pan-Cancer Analysis of MTF2 Effects on Human Tumors

Understanding oncogenic processes and underlying mechanisms to advance research into human tumors is critical for effective treatment. Studies have shown that Metal regulatory transcription factor 2（MTF2) drives malignant progression in liver cancer and glioma. However, no systematic pan-cancer analysis of MTF2 has been performed. Here, we use University of California Santa Cruz, Cancer Genome Atlas , Genotype-Tissue Expression data, Tumor Immune Estimation Resource, and Clinical Proteomic Tumor Analysis Consortium bioinformatics tools to explore differential expression of MTF2 across different tumor types. MTF2 was found to be highly expressed in the cancer lines that were available through the respective databases included in the study, and overexpression of MTF2 may lead to a poor prognosis in tumor patients such as glioblastoma multiforme, brain lower grade glioma, KIPAN, LIHC, adrenocortical carcinoma, etc. We also validated MTF2 mutations in cancer, compared MTF2 methylation levels in normal and primary tumor tissues, analyzed the association of MTF2 with the immune microenvironment, and validated the functional role of MTF2 in glioma U87 and U251 and breast cancer MDA-MB-231 cell lines by cytometry. This also indicates that MTF2 has a promising application prospect in cancer treatment.

Metallothionein 2A (MT2A) controls cell proliferation and liver metastasis by controlling the MST1/LATS2/YAP1 signaling pathway in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the three major cancers in the world and is the cancer with the most liver metastasis. The present study aimed to investigate the role of metallothionein 2A (MT2A) in the modulation of CRC cell proliferation and liver metastasis, as well as its molecular mechanisms.

METHODS

The expression profile of metallothionein 2A (MT2A) in colorectal cancer retrieved from TCGA, GEO and Oncomine database. The biological effect of MT2A overexpression was investigated mainly involving cell proliferation and migration in CRC cells as well as growth and metastasis in CRC animal models. To explore the specific mechanism of MT2A metastasis in CRC, transcriptome sequencing was used to compare the overall expression difference between the control group and the MT2A overexpression group.

RESULTS

Metallothionein 2A (MT2A) was downregulated in the tumor tissues of patients with CRC compared to adjacent normal tissues and was related to the tumor M stage of patients. MT2A overexpression inhibited CRC cell proliferation and migration in cells, as well as growth and metastasis in CRC animal models. While knockdown of MT2A had the opposite effect in cells. Western blotting confirmed that MT2A overexpression promoted the phosphorylation of MST1, LAST2 and YAP1, thereby inhibiting the Hippo signaling pathway. Additionally, specific inhibitors of MST1/2 inhibited MT2A overexpression-mediated phosphorylation and relieved the inhibition of the Hippo signaling pathway, thus promoting cell proliferation. Immunohistochemistry in subcutaneous grafts and liver metastases further confirmed this result.

CONCLUSIONS

Our results suggested that MT2A is involved in CRC growth and liver metastasis. Therefore, MT2A and MST1 may be potential therapeutic targets for patients with CRC, especially those with liver metastases.

Suppression of histone deacetylase 1 by JSL-1 attenuates the progression and metastasis of cholangiocarcinoma via the TPX2/Snail axis

Histone deacetylases (HDACs) are entwined with the pathogenesis of various cancers and potentially serve as promising therapeutic targets. Herein, we intend to explore the potential role of HDAC1 inhibitor (JSL-1) in the tumorigenesis and metastasis of cholangiocarcinoma (CC) and to highlight the molecular basis of its function. As shown by bioinformatics analysis and immunohistochemical detection, high HDAC1 expression was witnessed in CC tissues relative to matched controls from patients with cholecystitis. The molecular network that HDAC1 silencing reduced the enrichment of HDAC1 and Snail on the TPX2 promoter was identified using immunoprecipitation and chromatin immunoprecipitation assays. Both short hairpin RNA (shRNA)-mediated knockdown of HDAC1 and JSL-1 treatment exhibited anti-proliferative, anti-migration and anti-invasion effects on CC cells through downregulation of TPX2. The in vivo xenograft model was developed in nude mice. Consistently, the anti-tumorigenic and anti-metastatic properties of shRNA against HDAC1 and HDAC1 inhibitor were validated in the in vivo settings. Taken together, our data supported the notion that HDAC1 inhibitor retards the initiation and development of CC via mediating the TPX2/Snail axis, highlighting the anti-tumor molecular network functioned in CC.

LncRNA CCAT1 sponges miR-218-5p to promote EMT, cellular migration and invasion of retinoblastoma by targeting MTF2

Retinoblastoma (RB) is the primary neoplasms of the retina that is most common in pediatrics age. Long non-coding RNAs (lncRNAs) has been noticed for strong relation to the occurrence and progress of retinoblastoma. Previously, we have demonstrated that lncRNA colon cancer-associated transcript 1 (CCAT1) in two RB cell lines SO-RB50 and Y79 was obviously overexpressed, and notably, lncRNA CCAT1 attenuated miR-218-5p expressionand induced proliferation, cell migration and invasion. But, how lncRNA CCAT1 acts in RB development and the potential molecular mechanisms remain to be determined. In this study, the expression levels of lncRNA CCAT1 and miR-218-5p were evaluated in RB tissues by Q-PCR, which established the results in the cell lines. Further, lncRNA CCAT1 was shown to promote epithelial-to-mesenchymal transition (EMT), cellular migration and invasion of RB cells by functional analysis of downregulation and overexpression of lncRNA CCAT1 with specific siRNA and pcDNA transfection. By performing bioinformatics and dual luciferase reporter assay, we verified the direct interaction between lncRNA CCAT1 and miR-218-5p. Besides, bioinformatics analysis indicated that metal regulatory transcription factor 2 (MTF2) might be a potent novel target for miR-218-5p, which was further validated with luciferase reporter assay, Q-PCR and also Western blot analysis. Functional analysis and rescue analysis showed that lncRNA CCAT1 via competitive binding to miR-218-5p to modulate MTF2 expression thus accelerate EMT, cell migration and invasion of RB. In conclusion, here we identified the lncRNA CCAT1/miR-218-5p/MTF2 axis in RB cell lines. Our investigations on the function of lncRNA CCAT1 and the roles of the related molecules hint a novel potential target fo RB therapy.

M6A RNA Methylation Regulator HNRNPC Contributes to Tumorigenesis and Predicts Prognosis in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most malignant glioma with a high death rate. N6-methyladenosine (m6A) RNA methylation plays an increasingly important role in tumors. The current study aimed to determine the function of the regulators of m6A RNA methylation in GBM. We evaluated the difference, interaction, and correlation of these regulators with TCGA database. HNRNPC, WTAP, YTHDF2 and, YTHDF1 were significantly upregulated in GBM. To explore the expression characteristics of regulators in GBM, we defined two subgroups through consensus cluster. HNRNPC, WTAP, and YTHDF2 were significantly upregulated in the cluster2 which had a good overall survival (OS). To investigate the prognostic value of regulators, we used lasso cox regression algorithm to screen an independent prognostic risk characteristic based on the expression of HNRNPC, ZC3H13, and YTHDF2. The prognostic feature between the low and high-risk groups was significantly different (P < 0.05), which could predict significance of prognosis (area under the curve (AUC) = 0.819). Moreover, we used western blot, RT-PCR, and immunohistochemical staining to verify the expression of HNRNPC was associated with malignancy and development of gliomas. Similarly, the high expression of HNRNPC had a good prognosis. In conclusion, HNRNPC is a vital participant in the malignant progression of GBM and might be valuable for prognosis.

Recent progress in treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. In the past decade, there have been improvements in non-drug therapies and drug therapies for HCC treatment. Non-drug therapies include hepatic resection, liver transplantation, transarterial chemoembolization (TACE) and ablation. The former two surgical treatments are beneficial for patients with early and mid-stage HCC. As the first choice for non-surgical treatment, different TACE methods has been developed and widely used in combination therapy. Ablation has become an important alternative therapy for the treatment of small HCC or cases of unresectable surgery. Meanwhile, the drugs including small molecule targeted drugs like sorafenib and lenvatinib, monoclonal antibodies such as nivolumab are mainly used for the systematic treatment of advanced HCC. Besides strategies described above are recommended as first-line therapies due to their significant increase in mean overall survival, there are also potential drugs in clinical trials or under preclinical development. In addition, a number of potential preclinical surgical or adjuvant therapies are being studied, such as oncolytic virus, mesenchymal stem cells, biological clock, gut microbiome composition and peptide vaccine, all of which have shown different degrees of inhibition on HCC. With some potential anti-HCC drugs being reported, many promising therapeutic targets in related taxonomic signaling pathways including cell cycle, epigenetics, tyrosine kinase and so on that affect the progression of HCC have also been found. Together, the rational application of existing therapies and drugs as well as the new strategies will bring a bright future for the global cure of HCC in the coming decades.

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.

WHSC1 Promotes Cell Proliferation, Migration, and Invasion in Hepatocellular Carcinoma by Activating mTORC1 Signaling

Background

Wolf-Hirschhorn syndrome candidate gene-1 (WHSC1) plays key regulatory roles in cancer development and progression. However, its specific functions and potential mechanisms of action remain to be described in hepatocellular carcinoma (HCC).

Materials and Methods

WHSC1 expression in HCC was evaluated using The Cancer Genome Atlas and verified in HCC tissues and cell lines using qRT-PCR, Western blotting, and immunohistochemistry. Functional assays were performed to explore the role of WHSC1 in HCC progression. Immunoprecipitation-mass spectrometry, co-immunoprecipitation, immunofluorescence, and immunohistochemistry were conducted to evaluate the interaction between WHSC1 and prolyl 4-hydroxylase subunit beta (P4HB). Pathway enrichment was performed using gene set enrichment analysis.

Results

WHSC1 was markedly overexpressed in HCC tissues and cell lines. The level of expression was strongly associated with adverse clinicopathological characteristics. Survival analyses revealed that WHSC1 upregulation predicted poor overall survival and higher recurrence rates in patients with HCC. Functional studies revealed that WHSC1 significantly stimulated HCC proliferation, migration, and invasion in vitro and in vivo. WHSC1 was shown to interact with P4HB to stimulate P4HB expression and subsequently activate mTOR1 signaling.

Conclusion

We determined the oncogenic role of WHSC1 in HCC, via P4HB interaction, which activates mTOR1 signaling, and identified WHSC1 as a promising therapeutic target for HCC.