Overexpression of SMYD3 was associated with increased STAT3 activation in gastric cancer

The novel SMYD3 inhibitor EM127 impairs DNA repair response to chemotherapy-induced DNA damage and reverses cancer chemoresistance

BACKGROUND

SMYD3 has been found implicated in cancer progression. Its overexpression correlates with cancer growth and invasion, especially in gastrointestinal tumors. SMYD3 transactivates multiple oncogenic mechanisms, favoring cancer development. Moreover, it was recently shown that SMYD3 is required for DNA restoration by promoting homologous recombination (HR) repair.

METHODS

In cellulo and in vivo models were employed to investigate the role of SMYD3 in cancer chemoresistance. Analyses of SMYD3-KO cells, drug-resistant cancer cell lines, patients' residual gastric or rectal tumors that were resected after neoadjuvant therapy and mice models were performed. In addition, the novel SMYD3 covalent inhibitor EM127 was used to evaluate the impact of manipulating SMYD3 activity on the sensitization of cancer cell lines, tumorspheres and cancer murine models to chemotherapeutics (CHTs).

RESULTS

Here we report that SMYD3 mediates cancer cell sensitivity to CHTs. Indeed, cancer cells lacking SMYD3 functions showed increased responsiveness to CHTs, while restoring its expression promoted chemoresistance. Specifically, SMYD3 is essential for the repair of CHT-induced double-strand breaks as it methylates the upstream sensor ATM and allows HR cascade propagation through CHK2 and p53 phosphorylation, thereby promoting cancer cell survival. SMYD3 inhibition with the novel compound EM127 showed a synergistic effect with CHTs in colorectal, gastric, and breast cancer cells, tumorspheres, and preclinical colorectal cancer models.

CONCLUSIONS

Overall, our results show that targeting SMYD3 may be an effective therapeutic strategy to overcome chemoresistance.

Histone and DNA Methylation as Epigenetic Regulators of DNA Damage Repair in Gastric Cancer and Emerging Therapeutic Opportunities

Gastric cancer (GC), one of the most common malignancies worldwide, is a heterogeneous disease developing from the accumulation of genetic and epigenetic changes. One of the most critical epigenetic alterations in GC is DNA and histone methylation, which affects multiple processes in the cell nucleus, including gene expression and DNA damage repair (DDR). Indeed, the aberrant expression of histone methyltransferases and demethylases influences chromatin accessibility to the DNA repair machinery; moreover, overexpression of DNA methyltransferases results in promoter hypermethylation, which can suppress the transcription of genes involved in DNA repair. Several DDR mechanisms have been recognized so far, with homologous recombination (HR) being the main pathway involved in the repair of double-strand breaks. An increasing number of defective HR genes are emerging in GC, resulting in the identification of important determinants of therapeutic response to DDR inhibitors. This review describes how both histone and DNA methylation affect DDR in the context of GC and discusses how alterations in DDR can help identify new molecular targets to devise more effective therapeutic strategies for GC, with a particular focus on HR-deficient tumors.

MicroRNA-155 and cancer metastasis: Regulation of invasion, migration, and epithelial-to-mesenchymal transition

Among the leading causes of death globally has been cancer. Nearly 90% of all cancer-related fatalities are attributed to metastasis, which is the growing of additional malignant growths out of the original cancer origin. Therefore, a significant clinical need for a deeper comprehension of metastasis exists. Beginning investigations are being made on the function of microRNAs (miRNAs) in the metastatic process. Tiny non-coding RNAs called miRNAs have a crucial part in controlling the spread of cancer. Some miRNAs regulate migration, invasion, colonization, cancer stem cells' properties, the epithelial-mesenchymal transition (EMT), and the microenvironment, among other processes, to either promote or prevent metastasis. One of the most well-conserved and versatile miRNAs, miR-155 is primarily distinguished by overexpression in a variety of illnesses, including malignant tumors. It has been discovered that altered miR-155 expression is connected to a number of physiological and pathological processes, including metastasis. As a result, miR-155-mediated signaling pathways were identified as possible cancer molecular therapy targets. The current research on miR-155, which is important in controlling cancer cells' invasion, and metastasis as well as migration, will be summarized in the current work. The crucial significance of the lncRNA/circRNA-miR-155-mRNA network as a crucial regulator of carcinogenesis and a player in the regulation of signaling pathways or related genes implicated in cancer metastasis will be covered in the final section. These might provide light on the creation of fresh treatment plans for controlling cancer metastasis.

SMYD3 regulates gastric cancer progression and macrophage polarization through EZH2 methylation

SET and MYND domain-containing protein 3 (SMYD3), a known histone methyltransferase, was reported to regulate cancer pathogenesis. However, its role in gastric development and progression remains unclear. EZH2 methylation had been associated with cancer metastasis, but the EZH2 methylation status in gastric cancer (GC) is unknown. Here, we report that EZH2 K421 methylation was responsible for gastric cancer cell soft agar colony formation, in vivo metastasis, and macrophage polarization. Mechanically, we identified SMYD3 as the methyltransferase of EZH2 at K421 residue which accelerates EZH2 Ubiquitin proteasome degradation. Cell harboring non-methylated EZH2 mutants promotes gastric cancer cell metastasis. Taken together, our results showed that SMYD3-EZH2 axis restricts gastric cancer metastasis via integrating epigenetic signaling.

OSgc: A Web Portal to Assess the Performance of Prognostic Biomarkers in Gastric Cancer

Evaluating the prognostic value of genes of interest in different populations of gastric cancer (GC) is difficult and time-consuming for basic and translational researchers even though many datasets are available in public dataset depositories. In the current study, we developed a robust web-based portal called OSgc (Online consensus Survival analysis of gastric cancer) that enables easy and swift verification of known and novel biomarker candidates in GC. OSgc is composed of gene expression profiling data and clinical follow-up information of 1,824 clinical GC cases, which are collected from 7 public independent datasets derived from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). By OSgc, users input the official gene symbol and will promptly retrieve the Kaplan-Meier survival plot with hazard ratio (HR) and log rank p value on the output webpage, by which users could assess the prognostic value of interesting genes for GC patients. Five survival end points containing overall survival, progression-free survival, progression-free interval, relapse-free survival, and disease-free survival could be measured in OSgc. OSgc can greatly help cancer biologists and clinicians to explore the effect of gene expression on patient survival. OSgc is freely available without restrictions at http://bioinfo.henu.edu.cn/GC/GCList.jsp.

Playing on the Dark Side: SMYD3 Acts as a Cancer Genome Keeper in Gastrointestinal Malignancies

Simple Summary

The activity of SMYD3 in promoting carcinogenesis is currently under debate. Growing evidence seems to confirm that SMYD3 overexpression correlates with poor prognosis, cancer growth and invasion, especially in gastrointestinal tumors. In this review, we dissect the emerging role played by SMYD3 in the regulation of cell cycle and DNA damage response by promoting homologous recombination (HR) repair and hence cancer cell genomic stability. Considering the crucial role of PARP1 in other DNA repair mechanisms, we also discuss a recently evaluated synthetic lethality approach based on the combined use of SMYD3 and PARP inhibitors. Interestingly, a significant proportion of HR-proficient gastrointestinal tumors expressing high levels of SMYD3 from the PanCanAtlas dataset seem to be eligible for this innovative strategy. This promising approach could be taken advantage of for therapeutic applications of SMYD3 inhibitors in cancer treatment.

Abstract

The SMYD3 methyltransferase has been found overexpressed in several types of cancers of the gastrointestinal (GI) tract. While high levels of SMYD3 have been positively correlated with cancer progression in cellular and advanced mice models, suggesting it as a potential risk and prognosis factor, its activity seems dispensable for autonomous in vitro cancer cell proliferation. Here, we present an in-depth analysis of SMYD3 functional role in the regulation of GI cancer progression. We first describe the oncogenic activity of SMYD3 as a transcriptional activator of genes involved in tumorigenesis, cancer development and transformation and as a co-regulator of key cancer-related pathways. Then, we dissect its role in orchestrating cell cycle regulation and DNA damage response (DDR) to genotoxic stress by promoting homologous recombination (HR) repair, thereby sustaining cancer cell genomic stability and tumor progression. Based on this evidence and on the involvement of PARP1 in other DDR mechanisms, we also outline a synthetic lethality approach consisting of the combined use of SMYD3 and PARP inhibitors, which recently showed promising therapeutic potential in HR-proficient GI tumors expressing high levels of SMYD3. Overall, these findings identify SMYD3 as a promising target for drug discovery.

Comprehensive Analysis of the Value of SMYD Family Members in the Prognosis and Immune Infiltration of Malignant Digestive System Tumors

Background

The SET and MYND domain-containing (SMYD) gene family comprises a set of genes encoding lysine methyltransferases. This study aimed to clarify the relationship between the expression levels of SMYD family members and the prognosis and immune infiltration of malignant tumors of the digestive system.

Methods

The Oncomine, Ualcan, Kaplan–Meier Plotter, cBioPortal, Metascape, and TIMER databases and tools were used to analyze the correlation of SMYD family mRNA expression, clinical stage, TP53 mutation status, prognostic value, gene mutation, and immune infiltration in patients with esophageal carcinoma (ESCA), liver hepatocellular carcinoma (LIHC), and stomach adenocarcinoma (STAD).

Results

In ESCA, the mRNA expression of SMYD2/3/4/5 was significantly correlated with the incidence rate, that of SMYD2/3 with the clinical stage, that of SMYD2/3/4/5 with TP53 mutation status, that of SMYD2/4/5 with overall survival (OS), and that of SMYD1/2/3/4 with relapse-free survival (RFS). In LIHC, the mRNA expression of SMYD1/2/3/4/5 was significantly correlated with the incidence rate, that of SMYD2/4/5 with the clinical stage, that of SMYD3/5 with TP53 mutation status, that of SMYD2/3/4/5 with OS, and that of SMYD3/5 with RFS. In STAD, the mRNA expression of SMYD2/3/4/5 was significantly correlated with the incidence rate, that of SMYD1/4 with the clinical stage, that of SMYD1/2/3/5 with TP53 mutation status, that of SMYD1/3/4 with OS, and that of SMYD1/3 with RFS. Furthermore, the function of SMYD family mutation-related genes in ESCA, LIHC, and STAD patients was mainly related to pathways, such as mitochondrial gene expression, mitochondrial matrix, and mitochondrial translation. The expression of SMYD family genes was significantly correlated with the infiltration of six immune cell types and eight types of immune check sites.

Conclusion

SMYD family genes are differentially expressed and frequently mutated in malignant tumors of the digestive system (ESCA, LIHC, and gastric cancer). They are potential markers for prognostic prediction and have important significance in immunity and targeted therapy.

Discovery of the SMYD3 Inhibitor BAY-6035 Using Thermal Shift Assay (TSA)-Based High-Throughput Screening

SMYD3 (SET and MYND domain-containing protein 3) is a protein lysine methyltransferase that was initially described as an H3K4 methyltransferase involved in transcriptional regulation. SMYD3 has been reported to methylate and regulate several nonhistone proteins relevant to cancer, including mitogen-activated protein kinase kinase kinase 2 (MAP3K2), vascular endothelial growth factor receptor 1 (VEGFR1), and the human epidermal growth factor receptor 2 (HER2). In addition, overexpression of SMYD3 has been linked to poor prognosis in certain cancers, suggesting SMYD3 as a potential oncogene and attractive cancer drug target. Here we report the discovery of a novel SMYD3 inhibitor. We performed a thermal shift assay (TSA)-based high-throughput screening (HTS) with 410,000 compounds and identified a novel benzodiazepine-based SMYD3 inhibitor series. Crystal structures revealed that this series binds to the substrate binding site and occupies the hydrophobic lysine binding pocket via an unprecedented hydrogen bonding pattern. Biochemical assays showed substrate competitive behavior. Following optimization and extensive biophysical validation with surface plasmon resonance (SPR) analysis and isothermal titration calorimetry (ITC), we identified BAY-6035, which shows nanomolar potency and selectivity against kinases and other PKMTs. Furthermore, BAY-6035 specifically inhibits methylation of MAP3K2 by SMYD3 in a cellular mechanistic assay with an IC₅₀ <100 nM. Moreover, we describe a congeneric negative control to BAY-6035. In summary, BAY-6035 is a novel selective and potent SMYD3 inhibitor probe that will foster the exploration of the biological role of SMYD3 in diseased and nondiseased tissues.

SMYD3: a regulator of epigenetic and signaling pathways in cancer

Chromatin modifiers and their implications in oncogenesis have been an exciting area of cancer research. These are enzymes that modify chromatin via post-translational modifications such as methylation, acetylation, sumoylation, phosphorylation, in addition to others. Depending on the modification, chromatin modifiers can either promote or repress transcription. SET and MYN-domain containing 3 (SMYD3) is a chromatin modifier that has been implicated in the development and progression of various cancer types. It was first reported to tri-methylate Histone 3 Lysine 4 (H3K4), a methylation mark known to promote transcription. However, since this discovery, other histone (H4K5 and H4K20, for example) and non-histone (VEGFR, HER2, MAP3K2, ER, and others) substrates of SMYD3 have been described, primarily in the context of cancer. This review aims to provide a background on basic characteristics of SMYD3, such as its protein structure and tissue expression profiles, discuss reported histone and non-histone substrates of SMYD3, and underscore prognostic and functional implications of SMYD3 in cancer. Finally, we briefly discuss ongoing efforts to develop inhibitors of SMYD3 for future therapeutic use. It is our hope that this review will help synthesize existing research on SMYD3 in an effort to propel future discovery.

Lysine Methyltransferases Signaling: Histones are Just the Tip of the Iceberg

Protein lysine methylation is a functionally diverse post-translational modification involved in various major cellular processes. Lysine methylation can modulate proteins activity, stability, localization, and/or interaction, resulting in specific downstream signaling and biological outcomes. Lysine methylation is a dynamic and fine-tuned process, deregulation of which often leads to human pathologies. In particular, the lysine methylome and its associated signaling network can be linked to carcinogenesis and cancer progression. Histone modifications and chromatin regulation is a major aspect of lysine methylation importance, but increasing evidence suggests that a high relevance and impact of non-histone lysine methylation signaling has emerged in recent years. In this review, we draw an updated picture of the current scientific knowledge regarding non-histone lysine methylation signaling and its implication in physiological and pathological processes. We aim to demonstrate the significance of lysine methylation as a major and yet underestimated posttranslational modification, and to raise the importance of this modification in both epigenetic and cellular signaling by focusing on the observed activities of SET- and 7β-strandcontaining human lysine methyltransferases. Recent evidence suggests that what has been observed so far regarding lysine methylation's implication in human pathologies is only the tip of the iceberg. Therefore, the exploration of the "methylome network" raises the possibility to use these enzymes and their substrates as promising new therapeutic targets for the development of future epigenetic and methyllysine signaling cancer treatments.

SMYD3 overexpression indicates poor prognosis and promotes cell proliferation, migration and invasion in non‑small cell lung cancer

SET and MYND domain-containing protein 3 (SMYD3) is a lysine methyltransferase, and its aberrant expression has been implicated in several malignancies. However, its clinical and biological roles in non-small cell lung cancer (NSCLC) remain unclear. In the present study, it was revealed that SMYD3 was significantly upregulated in NSCLC tissues, as compared with paired adjacent normal tissues. A high SMYD3 expression was associated with aggressive clinicopathological characteristics, as well as poor disease-free survival and overall survival (OS) in NSCLC patients. Multivariate analysis revealed that SMYD3 overexpression was an independent predictor of poor OS in NSCLC patients. In addition, SMYD3 knockdown inhibited cell proliferation, triggered apoptosis, and blocked migration and invasion in NSCLC cells in vitro, whereas stable SMYD3 overexpression promoted NSCLC cell proliferation. Furthermore, the SMYD3-silenced NSCLC cells became more sensitive, whereas the SMYD3-overexpressed NSCLC cells became more resistant to the apoptosis induced by cisplatin. Mechanistic analysis revealed that SMYD3 knockdown led to the upregulation of Bim, Bak and Bax, and the downregulation of Bcl-2, Bcl-xl, MMP-2 and MMP-9 in NSCLC cells. In combination, the present findings indicated that SMYD3 has oncogenic potential in the context of NSCLC, providing evidence that may be exploited for both prognostic and therapeutic purposes in the future.

Upregulation of SMYD3 and SMYD3 VNTR 3/3 polymorphism increase the risk of hepatocellular carcinoma

SMYD3 (SET and MYND domain-containing protein 3) is involved in histone modification, which initiates oncogenesis by activating transcription of multiple downstream genes. To investigate associations of variable numbers of tandem repeats (VNTR) variants in the SMYD3 gene promoter, SMYD3 serum levels and SMYD3 mRNA expression in hepatitis B virus (HBV) infection and clinical progression of related liver disease. SMYD3 VNTRs were genotyped in 756 HBV patients and 297 healthy controls. SMYD3 serum levels were measured in 293 patients and SMYD3 mRNA expression was quantified in 48 pairs of hepatocellular tumor and adjacent non-tumor liver tissues. Genotype SYMD3 VNTR 3/3 was more frequent among HCC patients than in controls (P_adjusted = 0.037). SMYD3 serum levels increased according to clinical progression of liver diseases (P = 0.01); HCC patients had higher levels than non-HCC patients (P = 0.04). Among patients with SMYD3 VNTR 3/3, HCC patients had higher SMYD3 levels than others (P < 0.05). SMYD3 mRNA expression was up-regulated in HCC tumor tissues compared to other tissues (P = 0.008). In conclusion, upregulation of SMYD3 correlates with the occurrence of HCC and SMYD3 VNTR 3/3 appears to increase the risk of HCC through increasing SMYD3 levels. SMYD3 may be an indicator for HCC development in HBV patients.

Chitooligosaccharides Modulate Glucose-Lipid Metabolism by Suppressing SMYD3 Pathways and Regulating Gut Microflora

Chitooligosaccharides (COS) have a variety of biological activities due to their positively charged amino groups. Studies have shown that COS have antidiabetic effects, but their molecular mechanism has not been fully elucidated. The present study confirmed that COS can reduce hyperglycemia and hyperlipidemia, prevent obesity, and enhance histological changes in the livers of mice with type 2 diabetes mellitus (T2DM). Additionally, treatment with COS can modulate the composition of the gut microbiota in the colon by altering the abundance of Firmicutes, Bacteroidetes, and Proteobacteria. Furthermore, in T2DM mice, treatment with COS can upregulate the cholesterol-degrading enzymes cholesterol 7-alpha-hydroxylase (CYP7A1) and incretin glucagon-like peptide 1 (GLP-1) while specifically inhibiting the transcription and expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), the key enzyme in cholesterol synthesis. Furthermore, using an oleic acid-induced hepatocyte steatosis model, we found that HMGCR can be directly transactivated by SET and MYND domain containing 3 (SMYD3), a transcriptional regulator, via 5'-CCCTCC-3' element in the promoter. Overexpression of SMYD3 can suppress the inhibitory effect of COS on HMGCR, and COS might regulate HMGCR by inhibiting SMYD3, thereby exerting hypolipidemic functions. To the best of our knowledge, this study is the first to illustrate that COS mediate glucose and lipid metabolism disorders by regulating gut microbiota and SMYD3-mediated signaling pathways.

Is MYND Domain-Mediated Assembly of SMYD3 Complexes Involved in Calcium Dependent Signaling?

Macromolecular complexes are essential to intracellular signal transduction by creating signaling niches and enabling a chain of reactions that transmit external signals into various cellular responses. Analysis of SMYD3 interactome indicates this protein lysine methyltransferase might be involved in calcium dependent signaling pathways through forming complexes with the phospholipase PLCB3, calcium/calmodulin dependent kinase CAMK2B, or calcineurin inhibitor RCAN3. SMYD3 is well-known as a histone H3K4 methyltransferase involved in epigenetic transcriptional regulation; however, any roles SMYD3 may play in signaling transduction remain unknown. KEGG pathway enrichment analysis reveals the SMYD3 interacting proteins are overrepresented in several signaling pathways such as estrogen signaling pathway, NOD-like receptor signaling pathway, and WNT signaling pathway. Sequence motif scanning reveals a significant enrichment of PXLXP motif in SMYD3 interacting proteins. The MYND domain of SMYD3 is known to bind to the PXLXP motif. The enrichment of the PXLXP motif suggests that the MYND domain is likely to be a key interaction module that mediates formation of some SMYD3 complexes. The presence of the PXLXP motifs in PLCB3 and CAMK2B indicates the potential role of the MYND domain in mediating complex formation in signaling. The structural basis of SMYD3 MYND domain-mediated interactions is unknown. The only available MYND-peptide complex structure suggests the MYND domain-mediated interaction is likely transient and dynamic. The transient nature will make this domain well-suited to mediate signaling transduction processes where it may allow rapid responses to cellular perturbations and changes in environment.

STAT3 promotes chronic lymphocytic leukemia progression through upregulating SMYD3 expression

INTRODUCTION

This study was designed to investigate the roles of STAT3 and SMYD3 in chronic lymphocytic leukemia and the regulatory relationship between STAT3 and SMYD3 in chronic lymphocytic leukemia.

MATERIAL AND METHODS

The expression of STAT3 and SMYD3 was determined by RT-qPCR and western blot in chronic lymphocytic leukemia samples and cells (MEC1, CLL). Small interfering RNA was used to knock down the mRNA level of STAT3 and the pcDNA3.1-SMYD3 plasmid was used to construct a SMYD3 overexpression model. An MTT assay was performed to evaluate cell proliferation. A transwell assay was used to detect cell invasion ability. Afterwards, a luciferase reporter assay and chromatin immunoprecipitation experiment (ChIP assay) were applied to confirm the correlation between STAT3 and SMYD3.

RESULTS

STAT3 was highly expressed in chronic lymphocytic leukemia mononuclear cells and cancerous cell lines. STAT3 knockdown dramatically inhibited the mRNA and protein expression of SMYD3 in MEC1 and CLL cell lines. The luciferase reporter assay combined with the ChIP assay revealed that STAT3 bound to the promoter region of STAT3 and contributed to the transcription of SMYD3. Knockdown of STAT3 positively correlated with inhibition of cell proliferation and invasion abilities, while overexpression of SMYD3 negatively correlated with inhibition of cell proliferation and invasion.

CONCLUSIONS

STAT3 may promote chronic lymphocytic leukemia progression through elevating SMYD3 expression. Targeting STAT3 and SMYD3 may be a potential therapeutic strategy for chronic lymphocytic leukemia.

STAT3-induced SMYD3 transcription enhances chronic lymphocytic leukemia cell growth in vitro and in vivo

OBJECTIVE AND DESIGN

The purpose of this study was to investigate the roles of SMYD3 and STAT3 in chronic lymphocytic leukemia (CLL) and the possible underlying mechanisms.

MATERIALS

Blood samples were collected from 20 patients with CLL and 20 hematologically normal donors. Human cell lines K562, HL-60, MEG-1, and BALL-1 were performed in vitro and BALB/c nude mouse was used in subcutaneous tumor experiments.

TREATMENT

WP1066 (30 mg/kg) was also injected intratumorally two days after the first lentivirus treatment and then every four days for a total of four injections and 3 µM WP1066 was carried out for 48 h to downregulate STAT3 phosphorylation.

METHODS

We performed studies using the human CLL cell line MEG-1 in vitro and nude mouse subcutaneous tumor experiments in vivo. Differential expression of RNAs was determined using qRT-PCR. The CCK-8 assay and colony formation assay were conducted to evaluate cell proliferation. Flow cytometry was performed to assess cell apoptosis. The relative protein levels were detected using western blotting. Chromatin immunoprecipitation (ChIP) assays, luciferase reporter assays and WP1066, a STAT3 inhibitor, were used to explore the regulatory mechanisms of proteases and transcription factors. A subcutaneous tumor model was constructed to verify the results in vivo.

RESULTS

SMYD3 and STAT3 expressions positively correlated with the progression of CLL. Upregulation of SMYD3 significantly promoted the proliferation and inhibited the expression of apoptosis-related genes. The results of the ChIP assays and luciferase reporter assays suggested that STAT3 targeted the promoter region of SMYD3 and, thus, promoted SMYD3 transcription. Downregulation of the phosphorylation of STAT3 by WP1066 notably inhibited the binding of STAT3 to the SMYD3 promoter, and subsequently downregulated SMYD3 transcription. The STAT3 inhibitor inhibited CLL cell growth in vivo, and overexpression of SMYD3 promoted CLL cell growth. Furthermore, overexpression of SMYD3 reversed the inhibitory effects of the STAT3 inhibitor on CLL cell growth.

CONCLUSIONS

The STAT3-mediated transcription of SMYD3 plays a role in promoting the progression of chronic lymphocytic leukemia.

SMYD3-associated pathway is involved in the anti-tumor effects of sulforaphane on gastric carcinoma cells

Sulforaphane (SFN), a natural compound derived from cruciferous vegetables, has been proved to possess potent anti-cancer activity. SMYD3 is a histone methyltransferase which is closely related to the proliferation and migration of cancer cells. This study showed that SFN could dose-dependently induce cell cycle arrest, stimulate apoptosis, and inhibit proliferation and migration of gastric carcinoma cells. Accompanied with these anti-cancer effects, SMYD3 and its downstream genes, myosin regulatory light chain 9, and cysteine-rich angiogenic inducer 61, was downregulated by SFN. Furthermore, overexpression of SMYD3 via transfection could abolish the effects of SFN, suggesting that SMYD3 might be an important mediator of SFN. To the best of our knowledge, this is the first report describing the role of SMYD3 in the anti-cancer of SFN. These findings might throw light on the development of novel anti-cancer drugs and functional food using SFN-rich cruciferous vegetables.

Regulation of miR-155 affects the invasion and migration of gastric carcinoma cells by modulating the STAT3 signaling pathway

Studies investigating the effects of microRNA (miR)-155 on the behavior of tumor cells have concentrated primarily on proliferation and apoptosis. The aim of the present study was to investigate the effect of miR-155 inhibitor on the metastatic and invasive ability of gastric carcinoma cells and whether this effect is mediated via the signal transduction and activators of transcription 3 (STAT3) signaling pathway. The miR-155 inhibitor and miR-155 negative control (NC) were transfected into the AGs and MKN-45 cell lines. The migratory and invasive abilities of the cells were analyzed. The level of phosphorylated (p-)STAT3 and the expression levels of matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF) and suppressor of cytokine signaling 1 (SOCS1) were also detected. For the AGS cell line, the cell counts (mean ± standard deviation) for the Transwell migration assay were 98.99±9.13 in the miR-155 NC group and 45.32±4.32 in the miR-155 inhibitor group (P<0.01). For the MKN-45 cell line, the cell counts for the migration assay were 129.99±10.12 and 50.36±5.2 in the miR-155 NC and miR-155 inhibitor groups, respectively (P<0.01). The cell counts of the AGS cell line for the invasion assay were 70.25±7.94 in the miR-155 NC group and 40.68±4.73 in the miR-155 inhibitor group (P<0.05). For the MKN-45 cell line, the cell counts for the invasion assay were 84.63±8.12 and 40.35±4.29 in the miR-155 NC and miR-155 inhibitor groups, respectively (P<0.05). Transfection with the miR-155 inhibitor was able to significantly decrease the level of p-STAT3 in the AGS and MKN-45 cell lines compared with the negative control group (all P<0.05). The levels of MMP2 and MMP9 expression were decreased following transfection with miR-155 in AGS and MKN-45 cells (both P<0.05). Notably, transfection with the miR-155 inhibitor was able to decrease the level of VEGF expression, whilst increasing the SOCS1 expression level compared with the negative control group (both P<0.05). Additionally, the downregulation of miR-155 expression in gastric carcinoma cell lines was able to significantly decrease the expression of VEGF, MMP2 and MMP9, thereby inhibiting the invasion and metastasis of gastric carcinoma cells.

Therapeutical potential of deregulated lysine methyltransferase SMYD3 as a safe target for novel anticancer agents

INTRODUCTION

SET and MYND domain containing-3 (SMYD3) is a member of the lysine methyltransferase family of proteins, and plays an important role in the methylation of various histone and non-histone targets. Proper functioning of SMYD3 is very important for the target molecules to determine their different roles in chromatin remodeling, signal transduction and cell cycle control. Due to the abnormal expression of SMYD3 in tumors, it is projected as a prognostic marker in various solid cancers. Areas covered: Here we elaborate on the general information, structure and the pathological role of SMYD3 protein. We summarize the role of SMYD3-mediated protein interactions in oncology pathways, mutational effects and regulation of SMYD3 in specific types of cancer. The efficacy and mechanisms of action of currently available SMYD3 small molecule inhibitors are also addressed. Expert opinion: The findings analyzed herein demonstrate that aberrant levels of SMYD3 protein exert tumorigenic effects by altering the epigenetic regulation of target genes. The partial involvement of SMYD3 in some distinct pathways provides a vital opportunity in targeting cancer effectively with fewer side effects. Further, identification and co-targeting of synergistic oncogenic pathways is suggested, which could provide much more beneficial effects for the treatment of solid cancers.

Novel Oxindole Sulfonamides and Sulfamides: EPZ031686, the First Orally Bioavailable Small Molecule SMYD3 Inhibitor

SMYD3 has been implicated in a range of cancers; however, until now no potent selective small molecule inhibitors have been available for target validation studies. A novel oxindole series of SMYD3 inhibitors was identified through screening of the Epizyme proprietary histone methyltransferase-biased library. Potency optimization afforded two tool compounds, sulfonamide EPZ031686 and sulfamide EPZ030456, with cellular potency at a level sufficient to probe the in vitro biology of SMYD3 inhibition. EPZ031686 shows good bioavailability following oral dosing in mice making it a suitable tool for potential in vivo target validation studies.

Prognostic Value and Clinicopathological Significance of p-stat3 Among Gastric Carcinoma Patients: A Systematic Review and Meta-Analysis

The overexpression of phosphorylated signal transducer and activator of transcription 3 (p-stat3) was detected in a variety of human tumors. The published studies on p-stat3 expression among gastric carcinoma patients remain controversial.In order to clarify the prognosis value of p-stat3 with overall survival and its association with clinicopathological characteristics in gastric carcinoma, we performed a systematic review and meta-analysis.Eligible studies were retrieved by searching PubMed, Embase, Cochrane library, and Chinese biomedical literature service system databases.Studies described the association between p-stat3 expression and clinicopathological characteristics and overall survival in gastric carcinoma patients; p-stat3 expression was detected by immunohistochemistry (IHC).Odds ratio (OR) and hazard ratio (HR) were considered as a measure of evaluating the association in meta-analysis; I was used to assess the heterogeneity across studies; publication bias was assessed with funnel plot, Egger test, and Begg test.Twenty-three studies including 2872 patients which evaluated the p-stat3 expression by IHC in gastric carcinoma were included. The pooled HR (HR = 2.02, 95% CI: 1.49-2.73, P < 0.00001) indicated that the increased p-stat3 expression was significantly associated with poor overall survival. In addition, when we investigated the association between p-stat3 overexpression and clinicopathological characteristics of gastric carcinoma, we found that the increased p-stat3 expression was significantly associated with tumor differentiation (poorly vs well-moderately: OR = 3.70, 95% CI: 1.98-6.93, P < 0.0001) and lymph node metastasis (present vs absent: OR = 2.40, 95% CI: 1.28-4.50, P = 0.007).The different type of primary antibody was used; the assessment methods of p-stat3 positive expression were defined differently; the locations of p-stat3 expression were different; the method of extrapolating HR from Kaplan-Meier survival curves did seem to be less reliable than when HR was extracted directly from literatures; sample sizes, the age of patients, and the follow-up durations are different.In conclusion, our meta-analysis indicates that the increased p-stat3 expression may be not only predict poor prognosis, but also be associated with worse tumor differentiation and lymph node metastasis in patients with gastric carcinoma.

Upregulated SMYD3 promotes bladder cancer progression by targeting BCLAF1 and activating autophagy

The recent discovery of a large number of histone methyltransferases reveals important roles of these enzymes in regulating tumor development and progression. SMYD3, a histone methyltransferase, is associated with poor prognosis of patients with prostate and gastric cancer. In the study, we attempted to investigate its putative oncogenic role on bladder cancer. Here, we report that SMYD3 frequently amplified in bladder cancer is correlated with bladder cancer progression and poor prognosis. Overexpression of SMYD3 promotes bladder cancer cell proliferation and invasion, whereas SMYD3 knockdown inhibits cancer cell growth and invasion. Mechanically, SMYD3 positively regulates the expression of BCL2-associated transcription factor 1 (BCLAF1). SMYD3 physically interacts with the promoter of BCLAF1 and upregulates its expression by accumulating di- and trimethylation of H3K4 at the BCLAF1 locus. We further show that SMYD3 overexpression in bladder cancer cells promotes autophagy activation, whereas BCLAF1 depletion inhibits SMYD3-induced autophagy. Finally, we demonstrate that SMYD3 promotes bladder cancer progression, at least in part by increasing BCLAF1 expression and activating autophagy. Our results establish a function for SMYD3 in autophagy activation and bladder cancer progression and suggest its candidacy as a new prognostic biomarker and target for clinical management of bladder cancer.

SET and MYND domain-containing protein 3 is overexpressed in human glioma and contributes to tumorigenicity

SET and MYND domain-containing protein 3 (SMYD3) is a histone H3 lysine 4 (H3K4) di- and tri-methyltransferase that forms a transcriptional complex with RNA polymerase II and plays an important role in early embryonic lineage commitment through the activation of lineage-specific genes. SMYD3 activates the transcription of oncogenes and cell cycle genes in gastric and breast cancer cells. However, the contribution of SMYD3 in glioma tumorigenesis remains unknown. Here, we determined the expression of SMYD3 and assessed its clinical significance in human glioma. We found that SMYD3 was overexpressed in human glioma but not in normal brain tissue. The level of SMYD3 protein expression in human glioma tissues was directly correlated with the glioma grade. The level of SMYD3 protein expression in human glioma tissues was inversely correlated with patient survival. Enforced SMYD3 expression promoted glioma LN-18 cell proliferation. Inhibition of SMYD3 expression in glioma T98G cells suppressed their anchorage‑independent growth in vitro and tumorigenicity in vivo. Furthermore, we found that SMYD3 regulated the expression of p53 protein, which is essential in SMYD3‑induced cell growth in glioma cells. These results showed that SMYD3 is overexpressed in human glioma and contributes to glioma tumorigenicity through p53. Therefore, SMYD3 may be a new potential therapeutic target for human malignant glioma.

Elevated Levels of SET and MYND Domain-Containing Protein 3 Are Correlated with Overexpression of Transforming Growth Factor-β1 in Gastric Cancer

BACKGROUND

The aim of this study was to investigate the messenger RNA and protein expressions of SET and MYND domain-containing protein 3 (SMYD3) and transforming growth factor-β1 (TGF-β1) in gastric cancer (GC) and to explore the correlations between these proteins and the biologic behavior of GC.

STUDY DESIGN

Expressions of SMYD3 and TGF-β1 were detected by real-time quantitative reverse transcription polymerase chain reaction and Western blot in GC tissues and adjacent nontumor tissues. In addition, SMYD3 and TGF-β1 expressions were analyzed by immunohistochemistry in formalin-fixed samples from 166 GC patients.

RESULTS

The messenger RNA and protein expression levels of SMYD3 and TGF-β1 in GC tissues were significantly higher than those in adjacent nontumor tissues. A significantly positive correlation was found between SMYD3 expression and TGF-β1 expression in GC tissues. In addition, the size of the primary tumor and lymph node metastasis were identified as the independently relative factors of SMYD3 expression in GC tissues, and lymph node metastasis was identified as the independently relative factor of TGF-β1 expression. Multivariate analysis demonstrated that the degree of differentiation, serosal invasion, lymph node metastasis, SMYD3 expression, and TGF-β1 expression were the independent prognostic indicators for GC. Transforming growth factor-β1 expression was one of the optimal prognostic predictors of patients identified using the Cox regression with Akaike Information Criterion value calculation.

CONCLUSIONS

SET and MYND domain-containing protein 3 expression and TGF-β1 expression in GC tissues were significantly and positively correlated. High expression levels of SMYD3 and TGF-β1 can indicate poor prognoses for GC patients.

Overexpression of SMYD3 and matrix metalloproteinase-9 are associated with poor prognosis of patients with gastric cancer

SET and MYND domain-containing protein 3 (SMYD3) plays a key role in the progression of human cancer. Matrix metalloproteinase (MMP)-9 is being related to tumor progression. It has been reported that SMYD3 and MMP-9 are overexpressed in human cancers. However, the exact roles of SMYD3 and MMP-9 in the metastasis and prognosis of gastric cancer (GC) remain unclear. The expressions of SMYD3 and MMP-9 were detected by semiquantitative reverse transcription polymerase chain reaction and Western blotting in gastric cancer and adjacent nontumor tissues. In addition, SMYD3 and MMP-9 expressions were analyzed by immunohistochemistry in formalin-fixed samples from 186 gastric cancer patients. The messenger RNA (mRNA) and protein expression levels of SMYD3 and MMP-9 in gastric cancer tissues were both significantly higher than those in adjacent nontumor tissues. In addition, the expression of SMYD3 was correlated with size of primary tumor and lymph node metastasis, while size of primary tumor and serosal invasion were identified as the independently relative factors of MMP-9 expression in GC tissues. SMYD3 expression and MMP-9 expression in GC tissues were significantly and positively correlated. Multivariate analysis results demonstrated that degree of differentiation, lymph node metastasis, TNM stage, SMYD3 expression, and MMP-9 expression were the independent prognostic indicators of gastric cancer. SMYD3 and MMP-9 may play important roles in tumor invasion, metastasis, and prognosis and could work as promising targets for prognostic prediction in gastric cancer.