ATM Signaling Pathway Is Implicated in the SMYD3-mediated Proliferation and Migration of Gastric Cancer Cells

Ataxia-Telangiectasia Mutated (ATM) gene signaling pathways in human cancers and their therapeutic implications

Cancer is a multifaceted disease driven by abnormal cell growth and poses a significant global health threat. The multifactorial causes, differences in individual susceptibility to therapeutic drugs, and induced drug resistance pose major challenges in addressing cancers effectively. One of the most important aspects in making cancers highly heterogeneous in their physiology lies in the genes involved and the changes occurring to some of these genes in malignant conditions. The Genetic factors have been implicated in the oncogenesis, progression, responses to treatment, and metastasis. One such gene that plays a key role in human cancers is the mutated form of the Ataxia-telangiectasia gene (ATM). ATM gene located on chromosome 11q23, plays a vital role in maintaining genomic stability. Understanding the genetic basis of A-T is crucial for diagnosis, management, and treatment. Breast cancer, lung cancer, prostate cancer, and gastric cancer exhibit varying relationships with the ATM gene and influence their pathways. Targeting the ATM pathway proves promising for enhancing treatment effectiveness, especially in conjunction with DNA damage response pathways. Analyzing the therapeutic consequences of ATM mutations, especially in these cancer types facilitates the approaches for early detection, intervention, development of personalized treatment approaches, and improved patient outcomes. This review emphasizes the role of the ATM gene in various cancers, highlighting its impact on DNA repair pathways and therapeutic responses.

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.

Lysine Methyltransferase EhPKMT2 Is Involved in the In Vitro Virulence of Entamoeba histolytica

Lysine methylation, a posttranslational modification catalyzed by protein lysine methyltransferases (PKMTs), is involved in epigenetics and several signaling pathways, including cell growth, cell migration and stress response, which in turn may participate in virulence of protozoa parasites. Entamoeba histolytica, the etiologic agent of human amebiasis, has four PKMTs (EhPKMT1 to EhPKMT4), but their role in parasite biology is unknown. Here, to obtain insight into the role of EhPKMT2, we analyzed its expression level and localization in trophozoites subjected to heat shock and during phagocytosis, two events that are related to amoeba virulence. Moreover, the effect of EhPKMT2 knockdown on those activities and on cell growth, migration and cytopathic effect was investigated. The results indicate that this enzyme participates in all these cellular events, suggesting that it could be a potential target for development of novel therapeutic strategies against amebiasis.

SMYD Family Members Serve as Potential Prognostic Markers and Correlate with Immune Infiltrates in Gastric Cancer

Background

The SMYD family comprises a group of genes encoding lysine methyltransferases, which are closely related to tumorigenesis. However, a systematic understanding of their role in gastric cancer (GC) is lacking.

Methods

Using databases and tools such as the Cancer Genome Atlas, Human Protein Atlas, Kaplan-Meier Plotter, Gene Expression Profiling Interactive Analysis, and Metascape, we comprehensively analyzed differences in SMYD expression and its prognostic value as well as the association of SMYDs with immune cell infiltration, tumor mutational burden (TMB), and microsatellite instability (MSI). We conducted functional enrichment analysis and explored a competing endogenous RNA mechanism regulating SMYD mRNA and protein levels in patients with GC.

Results

In GC, the expression of SMYD2/3/4/5 mRNA was significantly upregulated, as opposed to that of SMYD1 mRNA, which was significantly downregulated. The protein levels of SMYDs were consistent with mRNA levels. SMYD1/2/4/5 was negatively correlated with overall survival; SMYD1/2/3/5 was negatively correlated with progression-free survival. Our SMYD-based signature and nomogram model may be useful for inferring the prognosis of GC. All SMYDs were closely associated with the infiltration of six immune cell types: uncharacterized, CD8⁺ T, CD4⁺ T, macrophage, endothelial, and B cells. TMB was significantly negatively correlated with SMYD1 expression, while a significant positive correlation was observed with SMYD2/5. Furthermore, MSI was significantly positively correlated with SMYD2/5 expression. Long non-coding RNAs, such as chr22-38_28785274-29006793.1, XLOC_002309, and CTD-2008N3.1, were suggested to regulate SMYD expression by sponging multiple microRNAs.

Conclusion

SMYDs are differentially expressed in GC and are thus potential prognostic markers. SMYD expression is closely related to immune infiltration, TMB, and MSI, all of which are closely related to the response to targeted immune therapy.

SMYD3 associates with the NuRD (MTA1/2) complex to regulate transcription and promote proliferation and invasiveness in hepatocellular carcinoma cells

BACKGROUND

SMYD3, a member of the SET and MYND domain-containing (SMYD) family, is a histone methyltransferase (HMT) and transcription factor that plays an important role in transcriptional regulation in human carcinogenesis.

RESULTS

Using affinity purification and mass spectrometry assays to identify SMYD3-associated proteins in hepatocellular carcinoma (HCC) cells, we found several previously undiscovered SMYD3-interacting proteins, including the NuRD (MTA1/2) complex, the METTL family, and the CRL4B complex. Transcriptomic analysis of the consequences of knocking down SMYD3, MTA1, or MTA2 in HCC cells showed that SMYD3/NuRD complex targets a cohort of genes, some of which are critically involved in cell growth and migration. qChIP analyses showed that SMYD3 knockdown led to a significant reduction in the binding of MTA1 or MTA2 to the promoters of IGFBP4 and led to a significant decrease in H4K20me3 and a marked increase in H4Ac at the IGFBP4 promoter. In addition, we demonstrated that SMYD3 promotes cell proliferation, invasion, and tumorigenesis in vivo and in vitro and found that its expression is markedly upregulated in human liver cancer. Knockdown of MTA1 or MTA2 had the same effect as knockdown of SMYD3 on proliferation and invasion of hepatocellular carcinoma cells. Catalytic mutant SMYD3 could not rescue the phenotypic effects caused by knockdown of SMYD3. Inhibitors of SMYD3 effectively inhibited the proliferation and invasiveness of HCC cells.

CONCLUSIONS

These findings revealed that SMYD3 could transcriptionally repress a cohort of target genes expression by associating with the NuRD (MTA1/2) complex, thereby promoting the proliferation and invasiveness of HCC cells. Our results support the case for pursuing SMYD3 as a practical prognostic marker or therapeutic target against HCC.

Clinicopathological and Prognostic Significance of SMYD3 in Human Cancers: A Systematic Review and Meta-analysis

Background: Dysregulation of the SET and MYND domain-containing protein 3 (SMYD3) has been found in multiple cancers. This meta-analysis aimed to elucidate the association between SMYD3 expression and clinical outcomes in cancer. Methods: A systematic search of Web of Science, Embase, PubMed, Cochrane Library, and CNKI was conducted. The relationship between SMYD3 expression and cancer patients' overall survival (OS) was evaluated using pooled hazard ratios (HRs) and their corresponding confidence intervals (95% CIs). The association between SMYD3 expression and clinicopathological features was assessed using odds ratios (ORs) with 95% CIs, including tumor size, lymph node metastasis (LNM), distance metastasis, and TNM stage. Results: In total, 715 cancer patients with hepatocellular carcinoma, nonsmall cell lung carcinoma, esophageal squamous cell carcinoma, glioma, colorectal cancer, and/or bladder cancer from seven studies were included in our meta-analysis. SMYD3 overexpression was significantly associated with poor OS (HR = 1.81, 95% CI: 1.38-2.37, p < 0.01) with no heterogeneity (I² = 0.0%, p = 0.929) in various cancers. Subgroup analysis showed that the prognostic value of SMYD3 across multiple tumors was constant as the tumor type, sample size, and methods of data extraction changed. Increased SMYD3 expression was positively associated with LNM (OR = 1.88, 95% CI = 1.33-2.66, p < 0.001), tumor size (OR = 1.68, 95% CI: 1.09-2.60, p = 0.019), and advanced TNM stage (OR = 1.84, 95% CI: 1.25-2.69, p = 0.002). Conclusions: Upregulation of SMYD3 was significantly associated with poor prognosis in various cancers, suggesting that SMYD3 may be a useful prognostic biomarker.

Mast cell marker gene signature in head and neck squamous cell carcinoma

BACKGROUND

Mast cells can reshape the tumour immune microenvironment and greatly affect tumour occurrence and development. However, mast cell gene prognostic and predictive value in head and neck squamous cell carcinoma (HNSCC) remains unclear. This study was conducted to identify and establish a prognostic mast cell gene signature (MCS) for assessing the prognosis and immunotherapy response of patients with HNSCC.

METHODS

Mast cell marker genes in HNSCC were identified using single-cell RNA sequencing analysis. A dataset from The Cancer Genome Atlas was divided into a training cohort to construct the MCS model and a testing cohort to validate the model. Fluorescence in-situ hybridisation was used to evaluate the MCS model gene expression in tissue sections from patients with HNSCC who had been treated with programmed cell death-1 inhibitors and further validate the MCS.

RESULTS

A prognostic MCS comprising nine genes (KIT, RAB32, CATSPER1, SMYD3, LINC00996, SOCS1, AP2M1, LAT, and HSP90B1) was generated by comprehensively analysing clinical features and 47 mast cell-related genes. The MCS effectively distinguished survival outcomes across the training, testing, and entire cohorts as an independent prognostic factor. Furthermore, we identified patients with favourable immune cell infiltration status and immunotherapy responses. Fluorescence in-situ hybridisation supported the MCS immunotherapy response of patients with HNSCC prediction, showing increased high-risk gene expression and reduced low-risk gene expression in immunotherapy-insensitive patients.

CONCLUSIONS

Our MCS provides insight into the roles of mast cells in HNSCC prognosis and may have applications as an immunotherapy response predictive indicator in patients with HNSCC and a reference for immunotherapy decision-making.

Functions of SMYD proteins in biological processes: What do we know? An updated review

BACKGROUND

Epigenetic modifiers, such as methyltransferases, play crucial roles in the regulation of many biological processes, including development, cancer and multiple physiopathological conditions.

SUMMARY

The Su(Var)3-9, Enhancer-of-zeste and Trithorax (SET) and Myeloid, Nervy, and DEAF-1 (MYND) domain-containing (SMYD) protein family consists of five members in humans and mice (i.e. SMYD1, SMYD2, SMYD3, SMYD4 and SMYD5), which are known or predicted to have methyltransferase activity on histone and non-histone substrates. The abundance of information concerning SMYD2 and SMYD3 is of note, whereas the other members of the SMYD family have not been so thoroughly studied CONCLUSION: Here we review the literature regarding SMYD proteins published in the last five years, including basic molecular biology mechanistic studies using in vitro systems and animal models, as well as human studies with a more translational or clinical approach.

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.

SMYD3 promotes hepatocellular carcinoma progression by methylating S1PR1 promoters

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. SET and MYND domain-containing protein 3 (SMYD3) has been shown to promote the progression of various types of human cancers, including liver cancer; however, the detailed molecular mechanism is still largely unknown. Here, we report that SMYD3 expression in HCC is an independent prognostic factor for survival and promotes the proliferation and migration of HCC cells. We observed that SMYD3 upregulated sphingosine-1-phosphate receptor 1 (S1PR1) promoter activity by methylating histone 3 (H3K4me3). S1PR1 was expressed at high levels in HCC samples, and high S1PR1 expression was associated with shorter survival. S1PR1 expression was also positively correlated with SMYD3 expression in HCC samples. We confirmed that SMYD3 promotes HCC cell growth and migration in vitro and in vivo by upregulating S1PR1 expression. Further investigations revealed that SMYD3 affects critical signaling pathways associated with the progression of HCC through S1PR1. These findings strongly suggest that SMYD3 has a crucial function in HCC progression that is partially mediated by histone methylation at the downstream gene S1PR1, which affects key signaling pathways associated with carcinogenesis and the progression of HCC.

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.

Histone H3K4 Methyltransferases as Targets for Drug-Resistant Cancers

The KMT2 (MLL) family of proteins, including the major histone H3K4 methyltransferase found in mammals, exists as large complexes with common subunit proteins and exhibits enzymatic activity. SMYD, another H3K4 methyltransferase, and SET7/9 proteins catalyze the methylation of several non-histone targets, in addition to histone H3K4 residues. Despite these structural and functional commonalities, H3K4 methyltransferase proteins have specificity for their target genes and play a role in the development of various cancers as well as in drug resistance. In this review, we examine the overall role of histone H3K4 methyltransferase in the development of various cancers and in the progression of drug resistance. Compounds that inhibit protein-protein interactions between KMT2 family proteins and their common subunits or the activity of SMYD and SET7/9 are continuously being developed for the treatment of acute leukemia, triple-negative breast cancer, and castration-resistant prostate cancer. These H3K4 methyltransferase inhibitors, either alone or in combination with other drugs, are expected to play a role in overcoming drug resistance in leukemia and various solid cancers.

SMYD3 confers cisplatin chemoresistance of NSCLC cells in an ANKHD1-dependent manner

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Up-regulated SMYD3 correlates with worse prognosis and controls DDP resistance of NSCLC.

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ANKHD1 interacts with and is essential for SMYD3-induced DDP resistance.

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CDK2 is identified to be a downstream effector of SMYD3-ANKHD1 in NSCLC.

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SMYD3-ANKHD1 critically regulates the growth DDP-resistant NSCLC cells in vivo.

Background

Cisplatin (DDP) remains the backbone of chemotherapy for non-small cell lung cancer (NSCLC), yet its clinical efficacy is limited by DDP resistance. We aim to investigate the role of the SET and MYND domain-containing protein 3 (SMYD3) in DDP resistance of NSCLC.

Methods

Expression pattern of SMYD3 was determined in NSCLC tissues using qRT-PCR, which also validated its correlation with NSCLC clinicopathological stages. Impacts of SMYD3 on DDP resistance were evaluated by knocking down SMYD3 in DDP-resistant cells and overexpressing it in DDP-sensitive cells, and assessed for several phenotypes: IC₅₀ by MTT, long-term proliferation by colony formation, apoptosis and cell-cycle distribution by flow cytometry. The interaction between Ankyrin Repeat and KH Domain Containing 1 (ANKHD1) and SMYD3 was examined by co-immunoprecipitation and immunofluorescence. The transcriptional regulation of SMYD3 on cyclin-dependent kinase 2 (CDK2) promoter regions was confirmed using chromatin-immunoprecipitation. The in vivo experiments using DDP-resistant cells with altered SMYD3 and ANKHD1 expression were further performed to verify the SMYD3/ANKHD1 axis.

Results

Highly expressed SMYD3 was observed in NSCLC tissues or cells, acted as a sensitive indicator for NSCLC, correlated with higher TNM stages or resistant to DDP treatment, and shorter overall survival. The promotion of SMYD3 on DDP resistance requires co-regulator, ANKHD1. CDK2 was identified as a downstream effector. In vivo, SMYD3 knockdown inhibited the growth of DDP-resistant NSCLC cells, which was abolished by ANKHD1 overexpression.

Conclusions

SMYD3 confers NSCLC cells chemoresistance to DDP in an ANKHD1-dependent manner, providing novel therapeutic targets to overcome DDP resistance in NSCLC .

SMYD3-PARP16 axis accelerates unfolded protein response and mediates neointima formation

Neointimal hyperplasia after vascular injury is a representative complication of restenosis. Endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) is involved in the pathogenesis of vascular intimal hyperplasia. PARP16, a member of the poly(ADP-ribose) polymerases family, is correlated with the nuclear envelope and the ER. Here, we found that PERK and IRE1α are ADP-ribosylated by PARP16, and this might promote proliferation and migration of smooth muscle cells (SMCs) during the platelet-derived growth factor (PDGF)-BB stimulating. Using chromatin immunoprecipitation coupled with deep sequencing (ChIP-seq) analysis, PARP16 was identified as a novel target gene for histone H3 lysine 4 (H3K4) methyltransferase SMYD3, and SMYD3 could bind to the promoter of Parp16 and increased H3K4me3 level to activate its host gene's transcription, which causes UPR activation and SMC proliferation. Moreover, knockdown either of PARP16 or SMYD3 impeded the ER stress and SMC proliferation. On the contrary, overexpression of PARP16 induced ER stress and SMC proliferation and migration. In vivo depletion of PARP16 attenuated injury-induced neointimal hyperplasia by mediating UPR activation and neointimal SMC proliferation. This study identified SMYD3-PARP16 is a novel signal axis in regulating UPR and neointimal hyperplasia, and targeting this axis has implications in preventing neointimal hyperplasia related diseases.

EZH2 and SMYD3 expression in papillary thyroid cancer

Recent studies have revealed the significant role of SMYD3 and EZH2 genes in the development and aggressiveness of numerous types of malignant tumor. Therefore, the present study aimed to investigate the expression of SMYD3 and EZH2 in papillary thyroid cancer, and to determine the correlation between the expression of these genes and clinical characteristics. Resected thyroid tissue samples from 62 patients with papillary thyroid cancer were investigated. Thyroid tissue derived from the healthy regions of removed nodular goiters from 30 patients served as the control group. Reverse transcription-quantitative PCR analysis was employed to detect relative mRNA expression levels. Primer sequences and TaqMan^® hydrolysis probe positions for EZH2 and SMYD3 were determined using the Roche Universal ProbeLibrary Assay Design Center version 2.50. EZH2 expression was detected in all thyroid cancer samples and in 83.3% of benign lesions. Notably, EZH2 was revealed to be upregulated in thyroid cancer tissues compared with control tissues (P=0.0002). EZH2 expression was positively correlated with tumor stage (P<0.0001; r=0.504), and multiple comparison analysis revealed that the highest expression of EZH2 was detected in samples staged pT4 (P=0.0001). SMYD3 expression was detected in all thyroid cancer samples and in 96.7% of healthy thyroid tissues; notably, the expression levels were similar in both groups. In addition, there was no correlation between SMYD3 expression and the aggressiveness of papillary thyroid cancer. In conclusion, overexpression of the EZH2 gene may be associated with the development of papillary thyroid cancer and EZH2 may be a potential therapeutic target in papillary thyroid cancer.

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.

Targeting SMYD3 to Sensitize Homologous Recombination-Proficient Tumors to PARP-Mediated Synthetic Lethality

SMYD3 is frequently overexpressed in a wide variety of cancers. Indeed, its inactivation reduces tumor growth in preclinical in vivo animal models. However, extensive characterization in vitro failed to clarify SMYD3 function in cancer cells, although confirming its importance in carcinogenesis. Taking advantage of a SMYD3 mutant variant identified in a high-risk breast cancer family, here we show that SMYD3 phosphorylation by ATM enables the formation of a multiprotein complex including ATM, SMYD3, CHK2, and BRCA2, which is required for the final loading of RAD51 at DNA double-strand break sites and completion of homologous recombination (HR). Remarkably, SMYD3 pharmacological inhibition sensitizes HR-proficient cancer cells to PARP inhibitors, thereby extending the potential of the synthetic lethality approach in human tumors.

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SMYD3 phosphorylation by ATM favors the formation of HR complexes during DSB response

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SMYD3 mediates DSB repair by promoting RAD51 recruitment at DNA damage sites

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SMYD3 inhibition triggers a compensatory PARP-dependent DNA damage response

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Co-targeting SMYD3/PARP leads to synthetic lethality in HR-proficient cancer cells

SET and MYND domain-containing protein 3 inhibits tumor cell sensitivity to cisplatin

Cisplatin resistance has been a major factor limiting its clinical use as a chemotherapy drug. The present study aimed to investigate whether SET and MYND domain-containing protein 3 (SMYD3), a histone methyltransferase closely associated with tumors can affect the sensitivity of tumors to cisplatin chemotherapy. Real time-qPCR, western blotting, the luciferase reporter, MTT and clonogenic assays were performed to detect the effects of SMYD3 on the chemotherapy capacity of cisplatin. In the present study, SMYD3 exhibited different expression patterns in MCF-7 and T47D breast cancer cells. In addition, this differential expression was associated with tumor cell resistance to cisplatin. Furthermore, SMYD3 knockdown following small interfering RNA transfection increased cisplatin sensitivity, whereas SMYD3 overexpression decreased cisplatin sensitivity. In addition, SMYD3 knockdown synergistically enhanced cisplatin-induced cell apoptosis. SMYD3 expression was downregulated during cisplatin treatment. In addition, transcriptional regulatory activities of SMYD3 3'-untranslated region were also downregulated. These results suggested that SMYD3 may affect cell sensitivity to cisplatin and participate in the development of cisplatin resistance, which is a process that may involve microRNA-124-mediated regulation.

SMYD3: An Oncogenic Driver Targeting Epigenetic Regulation and Signaling Pathways

SMYD3 is a member of the SMYD lysine methylase family and plays an important role in the methylation of various histone and non-histone targets. Aberrant SMYD3 expression contributes to carcinogenesis and SMYD3 upregulation was proposed as a prognostic marker in various solid cancers. Here we summarize SMYD3-mediated regulatory mechanisms, which are implicated in the pathophysiology of cancer, as drivers of distinct oncogenic pathways. We describe SMYD3-dependent mechanisms affecting cancer progression, highlighting SMYD3 interplay with proteins and RNAs involved in the regulation of cancer cell proliferation, migration and invasion. We also address the effectiveness and mechanisms of action for the currently available SMYD3 inhibitors. The findings analyzed herein demonstrate that a complex network of SMYD3-mediated cytoplasmic and nuclear interactions promote oncogenesis across different cancer types. These evidences depict SMYD3 as a modulator of the transcriptional response and of key signaling pathways, orchestrating multiple oncogenic inputs and ultimately, promoting transcriptional reprogramming and tumor transformation. Further insights into the oncogenic role of SMYD3 and its targeting of different synergistic oncogenic signals may be beneficial for effective cancer treatment.

SMYD2 promotes cervical cancer growth by stimulating cell proliferation

Background

Cervical cancer is the most common gynecological malignancy with low terminal cure rate, and therefore new therapeutic targets are urgently needed to combat this disease. SMYD2, as an oncogene, is abnormal highly expressed in multiple types of tumors and further affects the occurrence and development, but the potential correlations between SMYD2 expression and cervical cancer progression is still unclear.

Methods

We first used the bioinformatics website to screen the data of cervical cancer in (The Cancer Genome Atlas) TCGA and survival analysis was used to find the different survival rates in the SMYD2 high expression group and low expression group. Through immunohistochemistry, the association between SMYD2 expression and clinical-pathological features of cervical cancer patients was further evaluated. Quantitative PCR and Immunoblot were applied to investigate the relative mRNA and protein expression levels, respectively. In vivo and in vitro experiments were performed to explore the function of SMYD2 in cancer progression.

Results

We first found a high expression of SMYD2 in cervical cancer, and survival analysis found that the poorer survival rate in the SMYD2 high expression group than that in the low expression group. Herein, our study demonstrated that the expression of SMYD2 in patients with cervical cancer was associated with FIGO stage, tumor size and further correlated with poor prognosis. Our data further showed that the inhibition of SMYD2 expression in cervical cancer cell line Caski and Siha could dramatically block the proliferation of cervical cancer cells. Additionally, SMYD2-shRNA lentivirus infected remarkably inhibited tumorigenesis in mice compared with the scramble group.

Conclusions

Taken together, this study provides strong evidence of the involvement of SMYD2 in cervical cancer growth and indicates that it could have high potential as a therapeutic target of cervical cancer.

Cannabidiol Induces Cell Cycle Arrest and Cell Apoptosis in Human Gastric Cancer SGC-7901 Cells

The main chemical component of cannabis, cannabidiol (CBD), has been shown to have antitumor properties. The present study examined the in vitro effects of CBD on human gastric cancer SGC-7901 cells. We found that CBD significantly inhibited the proliferation and colony formation of SGC-7901 cells. Further investigation showed that CBD significantly upregulated ataxia telangiectasia-mutated gene (ATM) and p53 protein expression and downregulated p21 protein expression in SGC-7901 cells, which subsequently inhibited the levels of CDK2 and cyclin E, thereby resulting in cell cycle arrest at the G0–G1 phase. In addition, CBD significantly increased Bax expression levels, decreased Bcl-2 expression levels and mitochondrial membrane potential, and then upregulated the levels of cleaved caspase-3 and cleaved caspase-9, thereby inducing apoptosis in SGC-7901 cells. Finally, we found that intracellular reactive oxygen species (ROS) increased after CBD treatment. These results indicated that CBD could induce G0–G1 phase cell cycle arrest and apoptosis by increasing ROS production, leading to the inhibition of SGC-7901 cell proliferation, thereby suggesting that CBD may have therapeutic effects on gastric cancer.

Small-molecule inhibitors of lysine methyltransferases SMYD2 and SMYD3: current trends

Lysine methyltransferases SMYD2 and SMYD3 are involved in the epigenetic regulation of cell differentiation and functioning. Overexpression and deregulation of these enzymes have been correlated to the insurgence and progression of different tumors, making them promising molecular targets in cancer therapy even if their role in tumors is not yet fully understood. In this light, selective small-molecule inhibitors are required to fully understand and validate these enzymes, as this is a prerequisite for the development of successful targeted therapeutic strategies. The present review gives a systematic overview of the chemical probes developed to selectively target SMYD2 and SMYD3, with particular focus on the structural features important for high inhibitory activity, on the mode of inhibition and on the efficacy in cell-based and in in vivo models.

Amplification of SMYD3 promotes tumorigenicity and intrahepatic metastasis of hepatocellular carcinoma via upregulation of CDK2 and MMP2

SMYD3, a member that belongs to the SET and MYND-domain (SMYD) family, has also been proven to largely participate in gene transcription regulation and progression of several human cancers as a histone lysine methyltransferase. However, the role and significance of SMYD3 in both the clinic and progression of hepatocellular carcinoma (HCC) remain unclear. Herein, we find that SMYD3 is increased in cirrhotic livers, and strikingly upregulated in hepatocellular carcinoma (HCC) tissues and cell lines. Subsequent analyses suggest that high expression level of SMYD3 significantly correlates with the malignant characteristics of HCC, and predicts poor prognosis in patients. Our results show that overexpression of SMYD3 increases, while silencing of SMYD3 inhibits, cell proliferation, invasiveness and tumorigenicity both in vitro and in vivo. SMYD3 also promotes intrahepatic metastasis of HCC cells. For the mechanisms, we identify that SMYD3 bound to CDK2 and MMP2 promoter and increased H3K4me3 modification at the corresponding promoters to promote gene transcription. Importantly, pharmacological targeting of SMYD3 with BCI-121 inhibitor effectively repressed the tumorigenicity of HCC cells. Finally, our results show that gene locus amplification is a cause for SMYD3 overexpression in HCC. These findings not only uncover that SMYD3 overexpression promotes the tumorigenicity and intrahepatic metastasis of HCC cell via upregulation of CDK2 and MMP2, but also suggest SMYD3 could be a practical prognosis marker or therapeutic target against the disease.

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.

SMYD3 promoter hypomethylation is associated with the risk of colorectal cancer

AIM

SMYD3 encodes histone lysine methyltransferase. The goal of our study was to investigate the association between SMYD3 methylation and colorectal cancer (CRC).

MATERIALS & METHODS

SMYD3 methylation was measured by quantitative methylation-specific PCR method in 117 pairs of CRC tumor and para-tumor tissues.

RESULTS

Significantly lower SMYD3 methylation was observed in CRC tumor tissues than para-tumor tissues (p = 0.002). Further subgroup analysis by clinical features showed that significantly lower SMYD3 methylation were only observed in the CRC patients with tumors of moderately and well differentiation, positive lymph node metastasis, and stage III + IV.

CONCLUSION

Our work reported for the first time that SMYD3 promoter hypomethylation was associated with CRC.

Small molecule inhibitors and CRISPR/Cas9 mutagenesis demonstrate that SMYD2 and SMYD3 activity are dispensable for autonomous cancer cell proliferation

A key challenge in the development of precision medicine is defining the phenotypic consequences of pharmacological modulation of specific target macromolecules. To address this issue, a variety of genetic, molecular and chemical tools can be used. All of these approaches can produce misleading results if the specificity of the tools is not well understood and the proper controls are not performed. In this paper we illustrate these general themes by providing detailed studies of small molecule inhibitors of the enzymatic activity of two members of the SMYD branch of the protein lysine methyltransferases, SMYD2 and SMYD3. We show that tool compounds as well as CRISPR/Cas9 fail to reproduce many of the cell proliferation findings associated with SMYD2 and SMYD3 inhibition previously obtained with RNAi based approaches and with early stage chemical probes.