Negative regulation of SH2B3 by SMYD5 controls epithelial-mesenchymal transition in lung cancer.

The main cause of death in lung cancer patients is metastasis. Thus, efforts to suppress micrometastasis or distant metastasis in lung cancer, identify therapeutic targets and develop related drugs are ongoing. In this study, we identified SET and MYND domain-containing protein 5 (SMYD5) as a novel metastasis regulator in lung cancer and found that SMYD5 was overexpressed in lung cancer based on both RNA-sequencing analysis results derived from the TCGA portal and immunohistochemical analysis results; knockdown of SMYD5 inhibited cell migration and invasion by changing epithelial-mesenchymal transition markers and MMP9 expression in NCI-H1299 and H1703 cell lines. Additionally, SMYD5 knockdown increased Src homology 2-b3 expression by decreasing the level of H4K20 trimethylation. Furthermore, in an in vitro epithelial-mesenchymal transition system using TGF-ß treatment, SMYD5 knockdown resulted in reduced cell migration and invasion in the highly invasive NCI-H1299 and H1703 cell lines. Based on these findings, we propose that SMYD5 could serve as a potential therapeutic target for lung cancer treatment and that cotreatment with an SMYD5 inhibitor and chemotherapy may enhance the therapeutic effect of lung cancer treatment.

Epigenetic regulation of DHRS2 by SUV420H2 inhibits cell apoptosis in renal cell carcinoma.

Renal cell carcinoma (RCC), also known as kidney cancer, is a common malignant tumor of the urinary system. While surgical treatment is essential, novel therapeutic targets and corresponding drugs for RCC are still needed due to the high relapse rate and low five-year survival rate. In this study, we found that SUV420H2 is overexpressed in renal cancers and that high SUV420H2 expression is associated with a poor prognosis, as evidenced by RCC RNA-seq results derived from the TCGA. SUV420H2 knockdown using siRNA led to growth suppression and cell apoptosis in the A498 cell line. Furthermore, we identified DHRS2 as a direct target of SUV420H2 in the apoptosis process through a ChIP assay with a histone 4 lysine 20 (H4K20) trimethylation antibody. Rescue experiments showed that cotreatment with siSUV420H2 and siDHRS2 attenuated cell growth suppression induced by SUV420H2 knockdown only. Additionally, treatment with the SUV420H2 inhibitor A-196 induced cell apoptosis via upregulation of DHRS2. Taken together, our findings suggest that SUV420H2 may be a potential therapeutic target for the treatment of renal cancer.

Epigenetic regulation of SMAD3 by histone methyltransferase SMYD2 promotes lung cancer metastasis.

Epigenetic alterations, especially histone methylation, are key factors in cell migration and invasion in cancer metastasis. However, in lung cancer metastasis, the mechanism by which histone methylation regulates metastasis has not been fully elucidated. Here, we found that the histone methyltransferase SMYD2 is overexpressed in lung cancer and that knockdown of SMYD2 could reduce the rates of cell migration and invasion in lung cancer cell lines via direct downregulation of SMAD3 via SMYD2-mediated epigenetic regulation. Furthermore, using an in vitro epithelial-mesenchymal transition (EMT) system with a Transwell system, we generated highly invasive H1299 (In-H1299) cell lines and observed the suppression of metastatic features by SMYD2 knockdown. Finally, two types of in vivo studies revealed that the formation of metastatic tumors by shSMYD2 was significantly suppressed. Thus, we suggest that SMYD2 is a potential metastasis regulator and that the development of SMYD2-specific inhibitors may help to increase the efficacy of lung cancer treatment.

Epigenetic Silencing of CHOP Expression by the Histone Methyltransferase EHMT1 Regulates Apoptosis in Colorectal Cancer Cells.

Colorectal cancer (CRC) has a high mortality rate among cancers worldwide. To reduce this mortality rate, chemotherapy (5-fluorouracil, oxaliplatin, and irinotecan) or targeted therapy (bevacizumab, cetuximab, and panitumumab) has been used to treat CRC. However, due to various side effects and poor responses to CRC treatment, novel therapeutic targets for drug development are needed. In this study, we identified the overexpression of EHMT1 in CRC using RNA sequencing (RNA-seq) data derived from TCGA, and we observed that knocking down EHMT1 expression suppressed cell growth by inducing cell apoptosis in CRC cell lines. In Gene Ontology (GO) term analysis using RNA-seq data, apoptosis-related terms were enriched after EHMT1 knockdown. Moreover, we identified the CHOP gene as a direct target of EHMT1 using a ChIP (chromatin immunoprecipitation) assay with an anti-histone 3 lysine 9 dimethylation (H3K9me2) antibody. Finally, after cotransfection with siEHMT1 and siCHOP, we again confirmed that CHOP-mediated cell apoptosis was induced by EHMT1 knockdown. Our findings reveal that EHMT1 plays a key role in regulating CRC cell apoptosis, suggesting that EHMT1 may be a therapeutic target for the development of cancer inhibitors.

Cellular response of lung fibroblasts and epithelial cells to particulate matter10 treatment examined via comparative transcriptome analysis.

Particulate matter (PM) can be categorized by particle size (PM10, PM2.5 and PM1.0), which is an important factor affecting the biological response. Exposure to PM in the air (dust, smoke, dirt and biological contaminants) is clearly associated with lung disease (lung cancer, pneumonia and asthma). Although PM primarily affects lung epithelial cells, the specific response of related cell types to PM remains to be elucidated. The present study performed Gene Ontology (GO) analysis programs (Clustering GO and Database for Annotation, Visualization and Integrated Discovery) on differentially expressed genes in lung epithelial cells (WI­38 VA­13) and fibroblasts (WI­38) following treatment with PM10 and evaluated the cell­specific biological responses related to cell proliferation, apoptosis, adhesion and extracellular matrix production. The results suggested that short­ or long­term exposure to PM may affect cell condition and may consequently be related to several human diseases, including lung cancer and cardiopulmonary disease.

Human gut-microbiome-derived propionate coordinates proteasomal degradation via HECTD2 upregulation to target EHMT2 in colorectal cancer.

The human microbiome plays an essential role in the human immune system, food digestion, and protection from harmful bacteria by colonizing the human intestine. Recently, although the human microbiome affects colorectal cancer (CRC) treatment, the mode of action between the microbiome and CRC remains unclear. This study showed that propionate suppressed CRC growth by promoting the proteasomal degradation of euchromatic histone-lysine N-methyltransferase 2 (EHMT2) through HECT domain E3 ubiquitin protein ligase 2 (HECTD2) upregulation. In addition, EHMT2 downregulation reduced the H3K9me2 level on the promoter region of tumor necrosis factor α-induced protein 1 (TNFAIP1) as a novel direct target of EHMT2. Subsequently, TNFAIP1 upregulation induced the apoptosis of CRC cells. Furthermore, using Bacteroides thetaiotaomicron culture medium, we confirmed EHMT2 downregulation via upregulation of HECTD2 and TNFAIP1 upregulation. Finally, we observed the synergistic effect of propionate and an EHMT2 inhibitor (BIX01294) in 3D spheroid culture models. Thus, we suggest the anticancer effects of propionate and EHMT2 as therapeutic targets for colon cancer treatment and may provide the possibility for the synergistic effects of an EHMT2 inhibitor and microbiome in CRC treatment.

EHMT1 knockdown induces apoptosis and cell cycle arrest in lung cancer cells by increasing CDKN1A expression.

Dozens of histone methyltransferases have been identified and biochemically characterized, but the pathological roles of their dysfunction in human diseases such as cancer remain largely unclear. Here, we demonstrate the involvement of EHMT1, a histone lysine methyltransferase, in lung cancer. Immunohistochemical analysis indicated that the expression levels of EHMT1 are significantly elevated in human lung carcinomas compared with non-neoplastic lung tissues. Through gene ontology analysis of RNA-seq results, we showed that EHMT1 is clearly associated with apoptosis and the cell cycle process. Moreover, FACS analysis and cell growth assays showed that knockdown of EHMT1 induced apoptosis and G1 cell cycle arrest via upregulation of CDKN1A in A549 and H1299 cell lines. Finally, in 3D spheroid culture, compared to control cells, EHMT1 knockdown cells exhibited reduced aggregation of 3D spheroids and clear upregulation of CDKN1A and downregulation of E-cadherin. Therefore, the results of the present study suggest that EHMT1 plays a critical role in the regulation of cancer cell apoptosis and the cell cycle by modulating CDKN1A expression. Further functional analyses of EHMT1 in the context of human tumorigenesis may aid in the development of novel therapeutic strategies for cancer.

Low-dose interleukin-2 alleviates dextran sodium sulfate-induced colitis in mice by recovering intestinal integrity and inhibiting AKT-dependent pathways.

Several phase 1/2 clinical trials showed that low-dose interleukin-2 (IL-2) treatment is a safe and effective strategy for the treatment of chronic graft-versus-host disease, hepatitis C virus-induced vasculitis, and type 1 diabetes. Ulcerative colitis (UC) is a chronic inflammatory condition of the colon that lacks satisfactory treatment. In this study, we aimed to determine the effects of low-dose IL-2 as a therapeutic for UC on dextran sulfate sodium (DSS)-induced colitis. Methods: Mice with DSS-induced colitis were intraperitoneally injected with low-dose IL-2. Survival, body weight, disease activity index, colon length, histopathological score, myeloperoxidase activity and inflammatory cytokine levels as well as intestinal barrier integrity were examined. Differential gene expression after low-dose IL-2 treatment was analyzed by RNA-sequencing. Results: Low-dose IL-2 significantly improved the symptoms of DSS-induced colitis in mice and attenuated pro-inflammatory cytokine production and immune cell infiltration. The most effective dose range of IL-2 was 16K-32K IU/day. Importantly, low-dose IL-2 was effective in ameliorating the disruption of epithelial barrier integrity in DSS-induced colitis tissues by restoring tight junction proteins and mucin production and suppressing apoptosis. The colon tissue of DSS-induced mice exposed to low-dose IL-2 mimic gene expression patterns in the colons of control mice. Furthermore, we identified the crucial role of the PI3K-AKT pathway in exerting the therapeutic effect of low-dose IL-2. Conclusions: The results of our study suggest that low-dose IL-2 has therapeutic effects on DSS-induced colitis and potential clinical value in treating UC.

RNA-seq based transcriptome analysis of EHMT2 functions in breast cancer.

For breast cancer treatment, hormone therapy is effective for hormone receptor-positive breast cancer but not for TNBC (triple-negative breast cancer). Thus, many researchers have attempted to identify more effective therapeutic candidates for all subtypes of breast cancer. In this study, we established an RNA-seq analytical pipeline to analyze the subtype-specific functions of EHMT2 in the MB231 and MCF7 cell lines. After EHMT2 knockdown, we identified subtype-specific DEGs (differentially expressed genes) and overlapping DEGs. Through GO (Gene Ontology) analysis, GSEA (gene set enrichment analysis), and KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis using the DEGs, we identified the subtype-specific functions of EHMT2 in the MB231 and MCF7 cell lines. Therefore, herein, we suggest that EHMT2 is an attractive therapeutic target for the treatment of all types of breast cancer.

Propionate of a microbiota metabolite induces cell apoptosis and cell cycle arrest in lung cancer.

Short­chain fatty acids (SCFAs; butyrate, propionate and acetate) are metabolites derived from the gut microbiota via dietary fiber fermentation. In colon cancer, treatment with SCFAs, mainly butyrate and propionate, suppresses cell proliferation, migration and invasion. Furthermore, although sodium butyrate is known to induce cell apoptosis in lung cancer, the anticancer effects of sodium propionate (SP) on lung cancer are not well understood. In the present study, SP treatment induced cell cycle arrest, especially in the G2/M phase, and cell apoptosis in the H1299 and H1703 lung cancer cell lines. As determined by reverse transcription­quantitative PCR and western blotting, Survivin and p21 expression levels were significantly affected by SP treatment, suggesting that SP treatment suppressed cell proliferation in these lung cancer cell lines. Thus, it was proposed that the SP­mediated regulation of Survivin and p21 in lung cancer may be applicable to lung cancer therapy.

The novel prognostic marker, EHMT2, is involved in cell proliferation via HSPD1 regulation in breast cancer.

Molecular classifications of breast cancer (BRC), such as human epidermal growth factor receptor 2 (HER2), luminal A and luminal B, have been developed to reduce unnecessary treatment by dividing patients with BRC into low­ and high­risk progression groups. However, these methods do not cover all of the pathological characteristics of BRC, and investigations into novel prognostic/therapeutic markers are thus continually required. In this study, we identified the overexpression of the histone methyltransferase, euchromatic histone­lysine N­methyltransferase 2 (EHMT2) in BRC samples (n=1,222) and normal samples (n=113) derived from the TCGA portal by performing a BRC tissue microarray. EHMT2 overexpression was clearly associated with a poor prognosis in multiple cohorts of patients with BRC (total, n=1,644). Furthermore, the knockdown of EHMT2 expression affected cell apoptosis via the downregulation and re­localization of heat shock protein family D (Hsp60) member 1 (HSPD1). In addition, a statistically significant positive correlation between EHMT2 and HSPD1 expression was revealed in the clinical cohorts. On the whole, the findings of this study may assist the development of novel therapeutic strategies and provide a prognostic marker (EHMT2) for patients with BRC.

SETDB1 regulates SMAD7 expression for breast cancer metastasis.

Breast cancer (BRC) is the most invasive cancer in women. Although the survival rate of BRC is gradually increasing due to improved screening systems, development of novel therapeutic targets for inhibition of BRC proliferation, metastasis and recurrence have been constantly needed. Thus, in this study, we identified overexpression of SETDB1 (SET Domain Bifurcated 1), a histone methyltransferase, in RNA-seq data of BRC derived from TCGA portal. In Gene Ontology (GO) analysis, cell migration-related GO terms were enriched, and we confirmed down-regulation of cell migration/invasion and alteration of EMT /MET markers after knockdown of SETDB1. Moreover, gene network analysis showed that SMAD7 expression is regulated by SETDB1 levels, indicating that up-regulation of SMAD7 by SETDB1 knockdown inhibited BRC metastasis. Therefore, development of SETDB1 inhibitors and functional studies may help develop more effective clinical guidelines for BRC treatment. [BMB Reports 2019; 52(2): 139-144].

Downregulation of PRMT1, a histone arginine methyltransferase, by sodium propionate induces cell apoptosis in colon cancer.

The microbiota and bacterial metabolites in the colon are regarded as alternative targets for colon cancer prevention and therapy. Among these metabolites, short-chain fatty acids (SCFAs) exhibit anticancer effects and suppress inflammation in the colon. However, the molecular mechanisms and target development of SCFAs require additional study. In the present study, using RNA-seq results from colon cancer samples derived from the Cancer Genome Atlas (TCGA) portal, overexpressed epigenetic modifiers were identified and RT-PCR and qRT-PCR analysis was performed to select target genes that responded to treatment with propionate in HCT116 cells. Downregulation of protein arginine methyltransferase 1 (PRMT1), a histone arginine methyltransferase, was observed after sodium propionate (SP) treatment. Moreover, phospho-array analysis demonstrated that the mTOR pathway was involved in propionate and siPRMT1 treatment, and regulation of this pathway was associated with apoptosis in HCT116 cells. The present study, to the best of our knowledge, was the first to demonstrate that PRMT1 levels were reduced by propionate treatment in HCT116 cells and that downregulation of PRMT1 induced cell apoptosis. Thus, this novel mechanism of sodium propionate treatment for colon cancer therapy may indicate more effective approaches, such as dietary therapy, for CRC patients.

Hyperglycemia as a risk factor for cancer progression.

As the prevalence of diabetes mellitus is substantially increasing worldwide, associated diseases such as renal failure, cardiovascular diseases, fatty liver, and cancers have also increased. A number of cancers such as pancreatic, liver, breast, and female reproductive cancers have shown an increased prevalence and a higher mortality rate in diabetic patients compared to healthy subjects. Thus, this suggests an association between diabetes, especially type 2 diabetes and cancer incidence and progression. Recent studies have suggested that hyperinsulinemia, chronic inflammation and hyperglycemia, all frequently seen in diabetics, may lead to increased tumor growth; the underlying molecular mechanisms of this association are not fully understood. In particular, chronic hyperglycemic episodes could serve as a direct or indirect mediator of the increase in tumor cell growth. Here, we will discuss our current understanding how hyperglycemia and cancer risk may be linked, and what the implications are for the treatment of diabetic cancer patients.