G9a Promotes Invasion and Metastasis of Non-Small Cell Lung Cancer through Enhancing Focal Adhesion Kinase Activation via NF-κB Signaling Pathway

TLR9 in satellite glial cells promotes paclitaxel-induced neuropathic pain by reducing Kir4.1 transcription through histone methylation activation

Chemotherapy-induced neuropathic pain (CINP), commonly induced by paclitaxel (PTX), is a debilitating side effect that often leads to the discontinuation of cancer treatment. Despite its significant impact on patients' quality of life, the mechanisms underlying CINP remain poorly understood. Recent studies have suggested that immune system activation, particularly through Toll-like receptor 9 (TLR9), plays a crucial role in the development of neuropathic pain. In this study, we investigated the involvement of TLR9 in PTX-induced CINP, with a focus on satellite glial cells (SGCs) in the dorsal root ganglion (DRG). We found that TLR9 expression was significantly upregulated in SGCs following PTX treatment, and its activation contributed to the downregulation of Kir4.1 (potassium inwardly rectifying channel, subfamily J, member 10), a key potassium channel that regulates neuronal excitability. This process was mediated through histone methylation, involving the methyltransferase G9a and the NF-κB signaling pathway. Inhibition of TLR9 or knockdown of its expression alleviated PTX-induced pain behaviors while inhibiting G9a restored Kir4.1 function and reduced pain. These findings suggest that TLR9 and its downstream signaling pathways, including G9a-mediated histone modification, play a critical role in the development of CINP. Targeting TLR9 and histone methylation may provide novel therapeutic strategies for managing CINP and improving cancer treatment outcomes.

Integration analysis of cis- and trans-regulatory long non-coding RNAs associated with immune-related pathways in non-small cell lung cancer

Background

Long non-coding RNAs (lncRNAs) are importantly involved in the initiation and progression of non-small cell lung cancer (NSCLC). However, the classification and mechanisms of lncRNAs remain largely elusive.

Aim

Hence, we addressed this through bioinformatics analysis.

Methods and results

We utilized microarray technology to analyze lncRNAs and mRNAs in twenty paired NSCLC tumor tissues and adjacent normal tissues. Gene set enrichment analysis, Kyoto Encyclopedia of Genes and Genomes, and Gene Ontology were conducted to discern the biological functions of identified differentially expressed transcripts. Additionally, networks of lncRNA-mRNA co-expression, including cis-regulation, lncRNA-transcription factor (TF)-mRNA, trans-regulation, and lncRNA-miRNA-mRNA interactions were explored. Furthermore, the study examined differentially expressed transcripts and their prognostic values in a large RNA-seq dataset of 1016 NSCLC tumors and normal tissues extracted from the Cancer Genome Atlas (TCGA). The analysis revealed 391 lncRNAs and 344 mRNAs with differential expression in NSCLC tumor tissues compared to adjacent normal tissues. Subsequently, 43,557 co-expressed lncRNA-mRNA pairs were identified, including 27 lncRNA-mRNA pairs in cis, 9 lncRNA-TF-mRNA networks, 34 lncRNA-mRNA pairs in trans, and 8701 lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) networks. Notably, these lncRNAs were found to be involved in immune-related pathways. Six significant transcripts, including NTF4, PTPRD-AS, ITGA11, HID1-AS1, RASGRF2-AS1, and TBX2-AS1, were identified within the ceRNA network and trans-regulation.

Conclusion

This study brings important insights into the regulatory roles of lncRNAs in NSCLC, providing a fresh perspective on lncRNA research in tumor biology.

Mechanism and application of feedback loops formed by mechanotransduction and histone modifications

Mechanical stimulation is the key physical factor in cell environment. Mechanotransduction acts as a fundamental regulator of cell behavior, regulating cell proliferation, differentiation, apoptosis, and exhibiting specific signature alterations during the pathological process. As research continues, the role of epigenetic science in mechanotransduction is attracting attention. However, the molecular mechanism of the synergistic effect between mechanotransduction and epigenetics in physiological and pathological processes has not been clarified. We focus on how histone modifications, as important components of epigenetics, are coordinated with multiple signaling pathways to control cell fate and disease progression. Specifically, we propose that histone modifications can form regulatory feedback loops with signaling pathways, that is, histone modifications can not only serve as downstream regulators of signaling pathways for target gene transcription but also provide feedback to regulate signaling pathways. Mechanotransduction and epigenetic changes could be potential markers and therapeutic targets in clinical practice.

Mdm2 requires Sprouty4 to regulate focal adhesion formation and metastasis independent of p53

Although the E3 ligase Mdm2 and its homologue and binding partner MdmX are the major regulators of the p53 tumor suppressor protein, it is now evident that Mdm2 and MdmX have multiple functions that do not involve p53. As one example, it is known that Mdm2 can regulate cell migration, although mechanistic insight into this function is still lacking. Here we show in cells lacking p53 expression that knockdown of Mdm2 or MdmX, as well as pharmacological inhibition of the Mdm2/MdmX complex, not only reduces cell migration and invasion, but also impairs cell spreading and focal adhesion formation. In addition, Mdm2 knockdown decreases metastasis in vivo. Interestingly, Mdm2 downregulates the expression of Sprouty4, which is required for the Mdm2 mediated effects on cell migration, focal adhesion formation and metastasis. Further, our findings indicate that Mdm2 dampening of Sprouty4 is a prerequisite for maintaining RhoA levels in the cancer cells that we have studied. Taken together we describe a molecular mechanism whereby the Mdm2/MdmX complex through Sprouty4 regulates cellular processes leading to increase metastatic capability independently of p53.

Versatile function of NF-ĸB in inflammation and cancer

Nuclear factor-kappaB (NF-ĸB) plays a crucial role in both innate and adaptive immune systems, significantly influencing various physiological processes such as cell proliferation, migration, differentiation, survival, and stemness. The function of NF-ĸB in cancer progression and response to chemotherapy has gained increasing attention. This review highlights the role of NF-ĸB in inflammation control, biological mechanisms, and therapeutic implications in cancer treatment. NF-ĸB is instrumental in altering the release of inflammatory factors such as TNF-α, IL-6, and IL-1β, which are key in the regulation of carcinogenesis. Specifically, in conditions including colitis, NF-ĸB upregulation can intensify inflammation, potentially leading to the development of colorectal cancer. Its pivotal role extends to regulating the tumor microenvironment, impacting components such as macrophages, fibroblasts, T cells, and natural killer cells. This regulation influences tumorigenesis and can dampen anti-tumor immune responses. Additionally, NF-ĸB modulates cell death mechanisms, notably by inhibiting apoptosis and ferroptosis. It also has a dual role in stimulating or suppressing autophagy in various cancers. Beyond these functions, NF-ĸB plays a role in controlling cancer stem cells, fostering angiogenesis, increasing metastatic potential through EMT induction, and reducing tumor cell sensitivity to chemotherapy and radiotherapy. Given its oncogenic capabilities, research has focused on natural products and small molecule compounds that can suppress NF-ĸB, offering promising avenues for cancer therapy.

G9a in Cancer: Mechanisms, Therapeutic Advancements, and Clinical Implications

G9a, also named EHMT2, is a histone 3 lysine 9 (H3K9) methyltransferase responsible for catalyzing H3K9 mono- and dimethylation (H3K9me1 and H3K9me2). G9a contributes to various aspects of embryonic development and tissue differentiation through epigenetic regulation. Furthermore, the aberrant expression of G9a is frequently observed in various tumors, particularly in prostate cancer, where it contributes to cancer pathogenesis and progression. This review highlights the critical role of G9a in multiple cancer-related processes, such as epigenetic dysregulation, tumor suppressor gene silencing, cancer lineage plasticity, hypoxia adaption, and cancer progression. Despite the increased research on G9a in prostate cancer, there are still significant gaps, particularly in understanding its interactions within the tumor microenvironment and its broader epigenetic effects. Furthermore, this review discusses the recent advancements in G9a inhibitors, including the development of dual-target inhibitors that target G9a along with other epigenetic factors such as EZH2 and HDAC. It aims to bring together the existing knowledge, identify gaps in the current research, and suggest future directions for research and treatment strategies.

Inhibition of δ-catenin palmitoylation slows the progression of prostate cancer

Prostate cancer (PCa) is the second leading cause of death in males. It has been reported that δ-catenin expression is upregulated during the late stage of prostate cancer. Palmitoylation promotes protein transport to the cytomembrane and regulates protein localization and function. However, the effect of δ-catenin palmitoylation on the regulation of cancer remains unknown. In this study, we utilized prostate cancer cells overexpressing mutant δ-catenin (J6A cells) to induce a depalmitoylation phenotype and investigate its effect on prostate cancer. Our results indicated that depalmitoylation of δ-catenin not only reduced its membrane expression but also promoted its degradation in the cytoplasm, resulting in a decrease in the effect of EGFR and E-cadherin signaling. Consequently, depalmitoylation of δ-catenin reduced the proliferation and metastasis of prostate cancer cells. Our findings provide novel insights into potential therapeutic strategies for controlling the progression of prostate cancer through palmitoylation-based targeting of δ-catenin.

The Role and Mechanism of the Histone Methyltransferase G9a in Tumors: Update

Methylation-mediated gene silencing is closely related to the occurrence and development of human tumors. The euchromatic histone lysine methyltransferase 2 (EHMT2, also known as G9a) is highly expressed in many tumors and is generally considered to be an oncogene, which is associated with the poor outcome of many tumors. Combined immunotherapy and immune checkpoint blockade therapy also have good efficacy and certain safety. However, there are still many difficulties in the drugs targeting G9a, and the combined effect and safety of G9a with many drugs is still under study. This article aims to summarize the role and mechanism of G9a and its inhibitors in tumors in the past two years, and to understand the application prospect of G9a from the perspective of diagnosis and treatment.

Discovery of the First-in-Class G9a/GLP PROTAC Degrader

Aberrantly expressed lysine methyltransferases G9a and GLP, which catalyze mono- and dimethylation of histone H3 lysine 9 (H3K9), have been implicated in numerous cancers. Recent studies have uncovered both catalytic and noncatalytic oncogenic functions of G9a/GLP. As such, G9a/GLP catalytic inhibitors have displayed limited anticancer activity. Here, we report the discovery of the first-in-class G9a/GLP proteolysis targeting chimera (PROTAC) degrader 10 (MS8709), as a potential anticancer therapeutic. 10 induces G9a/GLP degradation in a concentration-, time-, and ubiquitin-proteasome system (UPS)-dependent manner. Futhermore, 10 does not alter the mRNA expression of G9a/GLP and is selective for G9a/GLP over other methyltransferases. Moreover, 10 displays superior cell growth inhibition to the parent G9a/GLP inhibitor UNC0642 in prostate, leukemia, and lung cancer cells and has suitable mouse pharmacokinetic properties for in vivo efficacy studies. Overall, 10 is a valuable chemical biology tool to further investigate the functions of G9a/GLP and a potential therapeutic for treating G9a/GLP-dependent cancers.

Role and potential therapeutic value of histone methyltransferases in drug resistance mechanisms in lung cancer

Lung cancer, ranking second globally in both incidence and high mortality among common malignant tumors, presents a significant challenge with frequent occurrences of drug resistance despite the continuous emergence of novel therapeutic agents. This exacerbates disease progression, tumor recurrence, and ultimately leads to poor prognosis. Beyond acquired resistance due to genetic mutations, mounting evidence suggests a critical role of epigenetic mechanisms in this process. Numerous studies have indicated abnormal expression of Histone Methyltransferases (HMTs) in lung cancer, with the abnormal activation of certain HMTs closely linked to drug resistance. HMTs mediate drug tolerance in lung cancer through pathways involving alterations in cellular metabolism, upregulation of cancer stem cell-related genes, promotion of epithelial-mesenchymal transition, and enhanced migratory capabilities. The use of HMT inhibitors also opens new avenues for lung cancer treatment, and targeting HMTs may contribute to reversing drug resistance. This comprehensive review delves into the pivotal roles and molecular mechanisms of HMTs in drug resistance in lung cancer, offering a fresh perspective on therapeutic strategies. By thoroughly examining treatment approaches, it provides new insights into understanding drug resistance in lung cancer, supporting personalized treatment, fostering drug development, and propelling lung cancer therapy into novel territories.

Discovery of the First-in-class G9a/GLP PROTAC Degrader

Aberrantly expressed lysine methyltransferases G9a and GLP, which catalyze mono- and di-methylation of histone H3 lysine 9 (H3K9), have been implicated in numerous cancers. Recent studies have uncovered both catalytic and non-catalytic oncogenic functions of G9a/GLP. As such, G9a/GLP catalytic inhibitors have displayed limited anticancer activity. Here, we report the discovery of the first-in-class G9a/GLP proteolysis targeting chimera (PROTAC) degrader, 10 (MS8709), as a potential anticancer therapeutic. 10 induces G9a/GLP degradation in a concentration-, time, and ubiquitin-proteasome system (UPS)-dependent manner, does not alter the mRNA expression of G9a/GLP and is selective for G9a/GLP over other methyltransferases. Moreover, 10 displays superior cell growth inhibition to the parent G9a/GLP inhibitor UNC0642 in prostate, leukemia, and lung cancer cells and has suitable mouse pharmacokinetic properties for in vivo efficacy studies. Overall, 10 is a valuable chemical biology tool to further investigate the functions of G9a/GLP and a potential therapeutic for treating G9a/GLP-dependent cancers.

Inhibition of USP7 upregulates USP22 and activates its downstream cancer-related signaling pathways in human cancer cells

Deubiquitinases (DUBs) play important roles in various human cancers and targeting DUBs is considered as a novel anticancer therapeutic strategy. Overexpression of ubiquitin specific protease 7 and 22 (USP7 and USP22) are associated with malignancy, therapy resistance, and poor prognosis in many cancers. Although both DUBs are involved in the regulation of similar genes and signaling pathways, such as histone H2B monoubiquitination (H2Bub1), c-Myc, FOXP3, and p53, the interdependence of USP22 and USP7 expression has never been described. In the study, we found that targeting USP7 via either siRNA-mediated knockdown or pharmaceutical inhibitors dramatically upregulates USP22 in cancer cells. Mechanistically, the elevated USP22 occurs through a transcriptional pathway, possibly due to desuppression of the transcriptional activity of SP1 via promoting its degradation upon USP7 inhibition. Importantly, increased USP22 expression leads to significant activation of downstream signal pathways including H2Bub1 and c-Myc, which may potentially enhance cancer malignancy and counteract the anticancer efficacy of USP7 inhibition. Importantly, targeting USP7 further suppresses the in vitro proliferation of USP22-knockout (USP22-Ko) A549 and H1299 lung cancer cells and induces a stronger activation of p53 tumor suppressor signaling pathway. In addition, USP22-Ko cancer cells are more sensitive to a combination of cisplatin and USP7 inhibitor. USP7 inhibitor treatment further suppresses in vivo angiogenesis and tumor growth and induced more apoptosis in USP22-Ko cancer xenografts. Taken together, our findings demonstrate that USP7 inhibition can dramatically upregulate USP22 in cancer cells; and targeting USP7 and USP22 may represent a more effective approach for targeted cancer therapy, which warrants further study. Video Abstract.

IDO1 facilitates esophageal carcinoma progression by driving the direct binding of NF-κB and CXCL10

Esophageal carcinoma (EC), one of the most lethal human malignancies, lacks effective targeted therapies. Indoleamine 2,3-dioxygenase 1 (IDO1) plays a key role in a variety of cancers, but its role and mechanism in EC are still unclear. Immunohistochemistry and qRT-PCR were used to analyze the expression of IDO1 in EC, and the prognostic value of IDO1 in EC was evaluated by Kaplan-Meier test. The in vitro and in vivo function loss/acquisition tests were performed to evaluate the biological effects of IDO1 in EC. The mechanism of action of IDO1-regulation EC was explored through Firefly luciferase & Renilla luciferase activity reporter, chromatin immunoprecipitation (ChIP) and immunofluorescence (IF) assays. Clinically, IDO1 expression was abnormally elevated in EC and positively correlated with overall survival. Functionally, IDO1 was contributed to the proliferation and migration of EC cells. Mechanically, IDO1 regulated the expression of chemokine C-X-C ligand 10 (CXCL10) by promoting the entry of NF-κB into the nucleus to combine with the promoter of CXCL10. Consistently, IDO1 facilitated EC progression may dependent on the presence of CXCL10. Moreover, NF-κB alleviated the inhibitory effect of IDO1 knockdown on EC. IDO1 drove the progression of EC by directly binding NF-κB and CXCL10, the finding that may provide an effective theoretical basis for precise therapies for EC.

Recent advances in developing degraders & inhibitors of lysine methyltransferases

Over the last several decades, there has been continued interest in developing novel therapeutic approaches targeting protein lysine methyltransferases (PKMTs). Along with PKMT inhibitors, targeted protein degradation (TPD) has emerged as a promising strategy to attenuate aberrant PKMT activity. Particularly, proteolysis targeting chimeras (PROTACs) effectively eliminate PKMTs of interest, suppressing all enzymatic and non-enzymatic functions. PROTACs and other TPD approaches add new depth to PKMT research and novel therapeutics discovery. This review focuses on recent advances in PKMT degrader and inhibitor development over the last several years.

High G9a Expression in DLBCL and Its Inhibition by Niclosamide to Induce Autophagy as a Therapeutic Approach

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is a malignant lymphoid tumor disease that is characterized by heterogeneity, but current treatment does not benefit all patients, which highlights the need to identify oncogenic genes and appropriate drugs. G9a is a histone methyltransferase that catalyzes histone H3 lysine 9 (H3K9) methylation to regulate gene function and expression in various cancers.

METHODS

TCGA and GTEx data were analyzed using the GEPIA2 platform. Cell viability under drug treatment was assessed using Alamar Blue reagent; the interaction between G9a and niclosamide was assessed using molecular docking analysis; mRNA and protein expression were quantified in DLBCL cell lines. Finally, G9a expression was quantified in 39 DLBCL patient samples.

RESULTS

The TCGA database analysis revealed higher G9a mRNA expression in DLBCL compared to normal tissues. Niclosamide inhibited DLBCL cell line proliferation in a time- and dose-dependent manner, reducing G9a expression and increasing p62, BECN1, and LC3 gene expression by autophagy pathway regulation. There was a correlation between G9a expression in DLBCL samples and clinical data, showing that advanced cancer stages exhibited a higher proportion of G9a-expressing cells.

CONCLUSION

G9a overexpression is associated with tumor progression in DLBCL. Niclosamide effectively inhibits DLBCL growth by reducing G9a expression via the cellular autophagy pathway; therefore, G9a is a potential molecular target for the development of therapeutic strategies for DLBCL.

Functional and clinical characteristics of focal adhesion kinases in cancer progression

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase and an adaptor protein that primarily regulates adhesion signaling and cell migration. FAK promotes cell survival in response to stress. Increasing evidence has shown that at the pathological level, FAK is highly expressed in multiple tumors in several systems (including lung, liver, gastric, and colorectal cancers) and correlates with tumor aggressiveness and patient prognosis. At the molecular level, FAK promotes tumor progression mainly by altering survival signals, invasive capacity, epithelial-mesenchymal transition, the tumor microenvironment, the Warburg effect, and stemness of tumor cells. Many effective drugs have been developed based on the comprehensive role of FAK in tumor cells. In addition, its potential as a tumor marker cannot be ignored. Here, we discuss the pathological and pre-clinical evidence of the role of FAK in cancer development; we hope that these findings will assist in FAK-based clinical studies.

Transcription factor AP2 enhances malignancy of non-small cell lung cancer through upregulation of USP22 gene expression

BACKGROUND

Ubiquitin-specific protease 22 (USP22), a putative cancer stem cell marker, is frequently upregulated in cancers, and USP22 overexpression is associated with aggressive growth, metastasis, and therapy resistance in various human cancers including lung cancer. However, USP22 gene amplification seldom occurs, and the mechanism underlying USP22 upregulation in human cancers remains largely unknown.

METHODS

A luciferase reporter driven by a promoter region of USP22 gene was selectively constructed to screen against a customized siRNA library targeting 89 selected transcription factors to identify potential transcription factors (TFs) that regulate USP22 expression in human non-small cell lung cancers (NSCLC). Association of identified TFs with USP22 and potential role of the TFs were validated and explored in NSCLC by biological assays and immunohistochemistry analysis.

RESULTS

Luciferase reporter assays revealed that SP1 and activating transcription factor 3 (ATF3) inhibit USP22 transcription, while transcription factor AP-2 Alpha/Beta (TFAP2A/2B) and c-Myc promote USP22 transcription. Binding site-directed mutagenesis and chromosome immunoprecipitation (ChIP) assays validated AP2α and AP2β are novel TFs of USP22. Furthermore, overexpression of AP2A and AP2B significantly upregulates USP22 expression, and its target: Cyclin D1, concurrently enhances the proliferation, migration, and invasion of NSCLC A549 and H1299 cells in a partially USP22-dependent manner. Moreover, AP2 protein level correlated with USP22 protein in human NSCLC tissues.

CONCLUSION

Our findings indicate AP2α and AP2β are important transcription factors driving USP22 gene expression to promote the progression of NSCLC, and further support USP22 as a potential biomarker and therapeutic target for lung cancer. Video Abstract.

Discovery of the First-in-Class G9a/GLP Covalent Inhibitors

The highly homologous protein lysine methyltransferases G9a and GLP, which catalyze mono- and dimethylation of histone H3 lysine 9 (H3K9), have been implicated in various human diseases. To investigate functions of G9a and GLP in human diseases, we and others reported several noncovalent reversible small-molecule inhibitors of G9a and GLP. Here, we report the discovery of the first-in-class G9a/GLP covalent irreversible inhibitors, 1 and 8 (MS8511), by targeting a cysteine residue at the substrate binding site. We characterized these covalent inhibitors in enzymatic, mass spectrometry based and cellular assays and using X-ray crystallography. Compared to the noncovalent G9a/GLP inhibitor UNC0642, covalent inhibitor 8 displayed improved potency in enzymatic and cellular assays. Interestingly, compound 8 also displayed potential kinetic preference for covalently modifying G9a over GLP. Collectively, compound 8 could be a useful chemical tool for studying the functional roles of G9a and GLP by covalently modifying and inhibiting these methyltransferases.

Potential Therapeutics Targeting Upstream Regulators and Interactors of EHMT1/2

Euchromatin histone lysine methyltransferases (EHMTs) are epigenetic regulators responsible for silencing gene transcription by catalyzing H3K9 dimethylation. Dysregulation of EHMT1/2 has been reported in multiple cancers and is associated with poor clinical outcomes. Although substantial insights have been gleaned into the downstream targets and pathways regulated by EHMT1/2, few studies have uncovered mechanisms responsible for their dysregulated expression. Moreover, EHMT1/2 interacting partners, which can influence their function and, therefore, the expression of target genes, have not been extensively explored. As none of the currently available EHMT inhibitors have made it past clinical trials, understanding upstream regulators and EHMT protein complexes may provide unique insights into novel therapeutic avenues in EHMT-overexpressing cancers. Here, we review our current understanding of the regulators and interacting partners of EHMTs. We also discuss available therapeutic drugs that target the upstream regulators and binding partners of EHMTs and could potentially modulate EHMT function in cancer progression.

KRT8 Serves as a Novel Biomarker for LUAD and Promotes Metastasis and EMT via NF-κB Signaling

Keratin 8 (KRT8) is the major component of the intermediate filament cytoskeleton and aberrant expression in multiple tumors. However, the role of KRT8 in lung adenocarcinoma (LUAD) remains unclear. In the present study, KRT8 expression was found to be upregulated along with prognosis and metastasis in LUAD. Kaplan-Meier analysis presented that the 5-year OS and DSS rates were significantly better among patients with low KRT8 expression compared to those with high expression. Correlation analysis showed that KRT8 expression was significantly associated with gender (P = 0.027), advanced T stage (P = 0.001), advanced N stage (P = 0.048), and advanced pathologic stage (P = 0.025). Univariate Cox analysis demonstrated that KRT8 was a predictor of OS [hazard ratio (HR) = 1.526; 95% confidence interval (CI) 1.141-2.040; P = 0.004] and DSS (HR = 1.625; 95% CI 1.123-2.353; P = 0.010) in the TCGA database. Importantly, downregulation of KRT8 obviously suppressed cell proliferation, cell migration, invasion, and EMT as well as induced cell apoptosis. KRT8 knockdown significantly inhibited NF-κB signaling, suggesting a potential mechanism. Overall, our results indicated that KRT8 could regulate lung carcinogenesis and may serve as a potential target for antineoplastic therapies.

Integrin α3/α6 and αV are implicated in ADAM15-activated FAK and EGFR signalling pathway individually and promote non-small-cell lung cancer progression

Disintegrin-metalloproteinase 15(ADAM15), a member of disintegrin metalloproteinases (ADAMs), plays important roles in various cancer types. However, the underlying ADAM15 functioning in lung cancer is still unclear. In the present study, we find that ADAM15 regulates the epidermal growth factor receptor/focal adhesion kinase (EGFR/FAK) signalling pathway by interactions with integrins. Integrin αV is involved in ADAM15-mediated FAK signalling. Further, we find that ADAM15 and CD151 were co-expressed, and the presence of ADAM15 affected the integrin α3/α6-related EGFR signalling pathway by cooperating with CD151. In addition, we also prove the effect of ADAM15 on proliferation in nude mice. Finally, we show that ADAM15 is a direct target of miR-204-5p by luciferase reporter assays, qRT-PCR and western blot analyses. Our findings provide molecular and cellular evidence that ADAM15 promotes cell proliferation and metastasis in NSCLC, which might provide a potential target for NSCLC treatment.

EHMT1/EHMT2 in EMT, Cancer Stemness and Drug Resistance: Emerging Evidence and Mechanisms

Metastasis, therapy failure and tumor recurrence are major clinical challenges in cancer. The interplay between tumor initiating cells (TICs) and Epithelial-Mesenchymal transition (EMT) drives tumor progression and spread. Recent advances have highlighted the involvement of epigenetic deregulation in these processes. The Euchromatin Histone Lysine Methyltransferase 1 (EHMT1) and Euchromatin Histone Lysine Methyltransferase 2 (EHMT2) that primarily mediate histone 3 lysine 9 di-methylation (H3K9me2), as well as methylation of non-histone proteins, are now recognized to be aberrantly expressed in many cancers. Their deregulated expression is associated with EMT, cellular plasticity and therapy resistance. In this review, we summarize evidence of their myriad roles in cancer metastasis, stemness and drug resistance. We discuss cancer-type specific molecular targets, context-dependent mechanisms and future directions of research in targeting EHMT1/EHMT2 for the treatment of cancer.

Structure, Activity, and Function of the Protein Lysine Methyltransferase G9a

G9a is a lysine methyltransferase catalyzing the majority of histone H3 mono- and dimethylation at Lys-9 (H3K9), responsible for transcriptional repression events in euchromatin. G9a has been shown to methylate various lysine residues of non-histone proteins and acts as a coactivator for several transcription factors. This review will provide an overview of the structural features of G9a and its paralog called G9a-like protein (GLP), explore the biochemical features of G9a, and describe its post-translational modifications and the specific inhibitors available to target its catalytic activity. Aside from its role on histone substrates, the review will highlight some non-histone targets of G9a, in order gain insight into their role in specific cellular mechanisms. Indeed, G9a was largely described to be involved in embryonic development, hypoxia, and DNA repair. Finally, the involvement of G9a in cancer biology will be presented.

Resveratrol and Its Analogs: Potent Agents to Reverse Epithelial-to-Mesenchymal Transition in Tumors

Epithelial-to-mesenchymal transition (EMT), a complicated program through which polarized epithelial cells acquire motile mesothelial traits, is regulated by tumor microenvironment. EMT is involved in tumor progression, invasion and metastasis via reconstructing the cytoskeleton and degrading the tumor basement membrane. Accumulating evidence shows that resveratrol, as a non-flavonoid polyphenol, can reverse EMT and inhibit invasion and migration of human tumors via diverse mechanisms and signaling pathways. In the present review, we will summarize the detailed mechanisms and pathways by which resveratrol and its analogs (e.g. Triacetyl resveratrol, 3,5,4'-Trimethoxystilbene) might regulate the EMT process in cancer cells to better understand their potential as novel anti-tumor agents. Resveratrol can also reverse chemoresistance via EMT inhibition and improvement of the antiproliferative effects of conventional treatments. Therefore, resveratrol and its analogs have the potential to become novel adjunctive agents to inhibit cancer metastasis, which might be partly related to their blocking of the EMT process.