MeCP2 Promotes Gastric Cancer Progression Through Regulating FOXF1/Wnt5a/β-Catenin and MYOD1/Caspase-3 Signaling Pathways

Mecp2 fine-tunes quiescence exit by targeting nuclear receptors

Quiescence (G0) maintenance and exit are crucial for tissue homeostasis and regeneration in mammals. Here, we show that methyl-CpG binding protein 2 (Mecp2) expression is cell cycle-dependent and negatively regulates quiescence exit in cultured cells and in an injury-induced liver regeneration mouse model. Specifically, acute reduction of Mecp2 is required for efficient quiescence exit as deletion of Mecp2 accelerates, while overexpression of Mecp2 delays quiescence exit, and forced expression of Mecp2 after Mecp2 conditional knockout rescues cell cycle reentry. The E3 ligase Nedd4 mediates the ubiquitination and degradation of Mecp2, and thus facilitates quiescence exit. A genome-wide study uncovered the dual role of Mecp2 in preventing quiescence exit by transcriptionally activating metabolic genes while repressing proliferation-associated genes. Particularly disruption of two nuclear receptors, Rara or Nr1h3, accelerates quiescence exit, mimicking the Mecp2 depletion phenotype. Our studies unravel a previously unrecognized role for Mecp2 as an essential regulator of quiescence exit and tissue regeneration.

SPCS, a Novel Classifier System Based on Senescence Axis Regulators Reveals Tumor Microenvironment Heterogeneity and Guides Frontline Therapy for Clear Cell Renal Carcinoma

RATIONALE

The emerging evidence suggested that senescence regulator genes were involved in multi cancers, which may be utilized as new targets for cancers. However, the dysregulation and clinical impact of senescence regulator genes in clear cell renal cell cancer (ccRCC) were still in foggy.

METHODS

Using multiomics data from TCGA-KIRC and other datasets, we comprehensively investigated the function of senescence regulator genes in ccRCC. ccRCC patients could be remodeled into 2 significant different groups basing on senescence regulators expression: senescence-pattern cancer subtype1 (SPCS1) and subtype2 (SPCS2). We further explored clinical characteristics, functional analysis, tumor immune microenvironment, immunotherapy response, genomic mutation and drug sensitivity between the 2 subtypes. Besides, senescence-pattern related risk model was established to determine the patient's prognosis of ccRCC. Finally, the overview of MECP2 function was investigated in multi cancers.

RESULTS

ccRCC patients could be divided into SPCS1 (normal aging group) and SPCS2 (Aging disorder group). The 2 subtypes showed significant different clinical characteristics and biological process in ccRCC. SPCS2, an aggressive subtype, comprised higher clinical stage and worse prognosis of ccRCC patients. SPCS2 subtype indicated activated oncogenic signaling pathway and metabolic signatures to prompt cancer expansion. SPCS2 subgroup owned immunocompromised status, which induced immune dysfunction and low ICI therapy response. The genome-copy numbers of SPCS2, including arm-gain and arm-loss was significantly more frequent than SPCS1. In addition, the 2 subtypes argue contrasting drug sensitivity profiles in clinical specimens and matched cell lines. Finally, we constructed a prognostic risk model consisted of each subtype's leading biomarkers, which exerted a satisfied performance for ccRCC patients.

CONCLUSION

Senescence regulator-related signature could modify functional pathways and tumor immune microenvironment by genome mutation and pathway interaction. Senescence regulator-related molecular subtype strengthen the understanding of ccRCC' characterization and guide clinical treatment. Targeting senescence regulators may be regard as a proper way in ccRCC.

HOXD3 promotes the migration and angiogenesis of hepatocellular carcinoma via modifying hepatocellular carcinoma cells exosome-delivered CCR6 and regulating chromatin conformation of CCL20

Angiogenesis plays an essential role in the microenvironment of hepatocellular carcinoma (HCC). HOXD3 is involved in the metastasis and invasion of HCC cells; Whereas the underlying molecular mechanisms in the microenvironment of HCC remain unknown. Wound healing, transwell invasion, tube formation and spheroid sprouting assays were carried out to identify the effects of HCC-HOXD3-exosomes and genes on the migration of HCC cells. ChIP-PCR was applied to test the binding region of HOXD3 on CCR6, Med15, and CREBBP promoter. Exosome isolation and mRNA-seq were applied to examine the morphological characteristics of exosomes and the contained mRNA in exosomes. Co-IP and Immunofluorescence assays were used to demonstrate the role of CREBBP in the chromatin conformation of CCL20. The nude mice were used to identify the function of genes in regulating migration of HCC in vivo. In this study, integrated cellular and bioinformatic analyses revealed that HOXD3 targeted the promoter region of CCR6 and induced its transcription. CCR6 was delivered by exosomes to endothelial cells and promoted tumour migration. Overexpression of CCR6 promoted metastasis, invasion in HCCs and angiogenesis in endothelial cells (ECs), whereas its downregulation suppressed these functions. The role of HOXD3 in the metastasis and invasion of HCC cells was reversed after the suppression of CCR6. Furthermore, CCL20 was demonstrated as the ligand of CCR6, and its high expression was found in HCC tissues and cells, which was clinically associated with the poor prognosis of HCC. Mechanistically, HOXD3 targets the promoter regions of CREBBP and Med15, which affect CCL20 chromatin conformation by regulating histone acetylation and expression of Pol II to enhance the migration of HCCs. This study demonstrated the function of the HOXD3-CREBBP/Med15-CCL20-CCR6 axis in regulating invasion and migration in HCC, thus providing new therapeutic targets for HCC.

BARX1 repressed FOXF1 expression and activated Wnt/β-catenin signaling pathway to drive lung adenocarcinoma

BACKGROUND

Underlying molecular mechanisms of BARX homeobox 1 (BARX1) in lung adenocarcinoma (LUAD) remain elusive.

METHODS

Abnormally expressed genes in LUAD tissues were analyzed by RNA-sequencing. CCK-8, colony formation, transwell, and wound healing assays examined proliferation, colony formation, invasion, and migration of LUAD cells, respectively. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay examined the interaction between BARX1 and Forkhead Box F1 (FOXF1). Xenograft mouse model of LUAD was constructed to monitor the growth and metastasis of tumor.

RESULTS

BARX1 was upregulated, FOXF1 was downregulated in LUAD tissues and cells. There was a negative correlation between BARX1 and FOXF1 expression. BARX1 deficiency limited malignant phenotypes of LUAD cells, including proliferation, invasion, migration and EMT. In vivo, BARX1 knockdown suppressed tumor growth and metastasis in A549-drove xenograft mouse model. BARX1 interacted with FOXF1 promoter and repressed FOXF1 expression. Upregulation of BARX1 promoted the expression of Wnt5a, β-catenin, and phosphorylated-glycogen synthase kinase-3 beta (p-GSK3β), whereas inhibited FOXF1, p-β-catenin, and GSK3β in LUAD cells. BARX1 knockdown caused an opposite result. Rescue assays uncovered that FOXF1 reversed the impact of BARX1 on malignant phenotypes and Wnt/β-catenin of LUAD cells.

CONCLUSION

BARX1 repressed FOXF1 expression and activated Wnt/β-catenin signaling pathway to drive lung adenocarcinoma.

MyoD1 promotes the transcription of BIK and plays an apoptosis-promoting role in the development of gastric cancer

Myogenic differentiation (MyoD) 1, which is known as a pivotal transcription factor during myogenesis, has been proven dysregulated in several cancers. However, litter is known about the precise role and downstream genes of MyoD1 in gastric cancer (GC) cells. Here, we report that MyoD1 is lowly expressed in primary GC tissues and cells. In our experiments, overexpression of MyoD1 inhibited cell proliferation. Downstream genes of MyoD1 regulation were investigated using RNA-Seq. As a result, 138 up-regulated genes and 20 down-regulated genes and 27 up-regulated lncRNAs and 20 down-regulated lncRNAs were identified in MyoD1 overexpressed MKN-45 cells, which participated in epithelial cell signaling in Helicobacter pylori infection, glycosaminoglycan biosynthesis (keratan sulfate), notch signaling pathway, and others. Among these genes, BIK was directly regulated by MyoD1 in GC cells and inhibited cancer cell proliferation. The BIK knockdown rescued the effects of MyoD1 overexpression on GC cells. In conclusion, MyoD1 inhibited cell proliferation via 158 genes and 47 lncRNAs downstream directly or indirectly that participated in multiple signaling pathways in GC, and among these, MyoD1 promotes BIK transcription by binding to its promoter, then promotes BIK-Bcl2-caspase 3 axis and regulates GC cell apoptosis.

Methylated Nucleotide-Based Proteolysis-Targeting Chimera Enables Targeted Degradation of Methyl-CpG-Binding Protein 2

Methyl-CpG-binding protein 2 (MeCP2), a reader of DNA methylation, has been extensively investigated for its function in neurological and neurodevelopmental disorders. Emerging evidence indicates that MeCP2 exerts an oncogenic function in cancer; however, the endeavor to develop a MeCP2-targeted therapy remains a challenge. This work attempts to address it by introducing a methylated nucleotide-based targeting chimera termed methyl-proteolysis-targeting chimera (methyl-PROTAC). The methyl-PROTAC incorporates a methylated cytosine into an oligodeoxynucleotide moiety to recruit MeCP2 for targeted degradation in a von Hippel-Lindau- and proteasome-dependent manner, thus displaying antiproliferative effects in cancer cells reliant on MeCP2 overexpression. This selective cytotoxicity endows methyl-PROTAC with the capacity to selectively eliminate cancer cells that are addicted to the overexpression of the MeCP2 oncoprotein. Furthermore, methyl-PROTAC-mediated MeCP2 degradation induces apoptosis in cancer cells. These findings underscore the therapeutic potential of methyl-PROTAC to degrade undruggable epigenetic regulatory proteins. In summary, the development of methyl-PROTAC introduces an innovative strategy by designing a modified nucleotide-based degradation approach for manipulating epigenetic factors, thereby representing a promising avenue for the advancement of PROTAC-based therapeutics.

Forniceal deep brain stimulation in a mouse model of Rett syndrome increases neurogenesis and hippocampal memory beyond the treatment period

BACKGROUND

Rett syndrome (RTT), caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2), severely impairs learning and memory. We previously showed that forniceal deep brain stimulation (DBS) stimulates hippocampal neurogenesis with concomitant improvements in hippocampal-dependent learning and memory in a mouse model of RTT.

OBJECTIVES

To determine the duration of DBS benefits; characterize DBS effects on hippocampal neurogenesis; and determine whether DBS influences MECP2 genotype and survival of newborn dentate granular cells (DGCs) in RTT mice.

METHODS

Chronic DBS was delivered through an electrode implanted in the fimbria-fornix. We tested separate cohorts of mice in contextual and cued fear memory at different time points after DBS. We then examined neurogenesis, DGC apoptosis, and the expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) after DBS by immunohistochemistry.

RESULTS

After two weeks of forniceal DBS, memory improvements lasted between 6 and 9 weeks. Repeating DBS every 6 weeks was sufficient to maintain the improvement. Forniceal DBS stimulated the birth of more MeCP2-positive than MeCP2-negative DGCs and had no effect on DGC survival. It also increased the expression of BDNF but not VEGF in the RTT mouse dentate gyrus.

CONCLUSION

Improvements in learning and memory from forniceal DBS in RTT mice extends well beyond the treatment period and can be maintained by repeated DBS. Stimulation of BDNF expression correlates with improvements in hippocampal neurogenesis and memory benefits.

The Association of Methylation Status and Expression Level of MyoD1 with DNMT1 Expression Level in Breast Cancer Patients

Background: Breast cancer (BC) is the most common malignancy in women worldwide. The methylation status of MyoD1, a tumor suppressor gene, is enrolled in various cancers, i.e., BC. Various studies showed the impact of MyoD1 epigenetic dysregulation in BC. This study aimed to investigate the methylation status and expression level of MyoD1 in BC patients and its association with the expression of DNMT1. Materials and Methods: This case-control study was conducted on 30 cases (pathology-confirmed ductal carcinoma) and 18 controls (fibroadenoma and fibrocystic masses), referred to Velayat Hospital, Qazvin, Iran. The expression of the MyoD1 and DNMT1 and the promoter methylation of the MyoD1 were evaluated in tissue blocks of BC patient masses using qRT-PCR and MS-PCR assays, respectively. SPSS 24.0 was used to analyze the data. Results: The MyoD1 promoter is hypermethylated in BC patients compared to controls (p =0.001). The expression level of MyoD1 in BC patients was significantly reduced compared to controls (fold change =0.13, p =0.042). In addition, in BC patients, the reduced expression level of MyoD1 was significantly associated with methylation of the MyoD1 promoter (p =0.001). There is no significant difference between the expression level of DNMT1 in BC patients and controls (p =0.197). A significant association is found between the expression of DNMT1 and the methylation status of the MyoD1 promoter (p =0.038). Discussion: The expression level of MyoD1 is affected by the methylation status of the promoter of this gene. Moreover, the expression level and methylation status of MyoD1 are correlated with clinical parameters.

The Epigenetic Reader Methyl-CpG-Binding Protein 2 (MeCP2) Is an Emerging Oncogene in Cancer Biology

Epigenetic mechanisms are gene regulatory processes that control gene expression and cellular identity. Epigenetic factors include the "writers", "readers", and "erasers" of epigenetic modifications such as DNA methylation. Accordingly, the nuclear protein Methyl-CpG-Binding Protein 2 (MeCP2) is a reader of DNA methylation with key roles in cellular identity and function. Research studies have linked altered DNA methylation, deregulation of MeCP2 levels, or MECP2 gene mutations to different types of human disease. Due to the high expression level of MeCP2 in the brain, many studies have focused on its role in neurological and neurodevelopmental disorders. However, it is becoming increasingly apparent that MeCP2 also participates in the tumorigenesis of different types of human cancer, with potential oncogenic properties. It is well documented that aberrant epigenetic regulation such as altered DNA methylation may lead to cancer and the process of tumorigenesis. However, direct involvement of MeCP2 with that of human cancer was not fully investigated until lately. In recent years, a multitude of research studies from independent groups have explored the molecular mechanisms involving MeCP2 in a vast array of human cancers that focus on the oncogenic characteristics of MeCP2. Here, we provide an overview of the proposed role of MeCP2 as an emerging oncogene in different types of human cancer.

Inhibiting lncRNA NEAT1 facilitates the sensitization of melanoma cells to cisplatin through modulating the miR-519c-3p-MeCP2 axis

Cutaneous melanoma is an aggressive human malignancy, leading to high mortality worldwide. In addition to surgery, radiotherapy and chemotherapy are routine approaches to treat melanoma at late or metastatic stage. However, a group of melanoma patients developed chemoresistance, which ultimately limited the efficiency of chemotherapy. LncRNA NEAT1 (Nuclear-enriched abundant transcript 1) is frequently overexpressed in various cancers. Currently, the precise roles and underlying mechanisms of NEAT1 in chemoresistant melanoma remain unclear. This study reports NEAT1 was significantly upregulated in melanoma tumor specimens and cell lines. Blocking NEAT1 effectively sensitized melanoma cells to cisplatin (CDDP), a frequently used first-line anticancer agent. From the established cisplatin resistant melanoma cell line (SK-MEL-5 CDDP Res), we detected significantly upregulated NEAT1 expression and downregulated miR-519c-3p expression compared with those from SK-MEL-5 parental cells. Subsequently, expression of miR-519c-3p was remarkedly attenuated in melanoma tumors and cell lines. Bioinformatics analysis, RNA pull-down assay and luciferase assay consistently demonstrated that NEAT1 sponged miR-519c-3p to downregulate its expression in melanoma cells. Moreover, we identified the methyl CpG binding protein 2 (MeCP2), which is positively associated with cisplatin resistance in melanoma, was a direct target of miR-519c-3p in melanoma cells. Restoration of MeCP2 rescued the miR-519c-3p-promoted cisplatin sensitization. Finally, we showed restoration of miR-519c-3p in NEAT1-overexpressing SK-MEL-5 CDDP Res cells successfully overrode the NEAT1-promoted cisplatin resistance in melanoma from in vitro and in vivo results. In summary, our results unveiled biological roles and molecular mechanisms of the noncoding RNA-mediated cisplatin resistance in melanoma, suggesting blocking the NEAT1-miR-519c-3p-MeCP2 axis as a therapeutic strategy against chemoresistant melanoma.

Butyrate prevents the migration and invasion, and aerobic glycolysis in gastric cancer via inhibiting Wnt/β-catenin/c-Myc signaling

Gastric cancer (GC) remains a common cause of cancer death worldwide. Evidence has found that butyrate exhibited antitumor effects on GC cells. However, the mechanism by which butyrate regulate GC cell proliferation, migration, invasion, and aerobic glycolysis remains largely unknown. The proliferation, migration, and invasion of GC cells were tested by EdU staining, transwell assays. Additionally, protein expressions were determined by western blot assay. Next, glucose uptake, lactate production, and cellular ATP levels in GC cells were detected. Furthermore, the antitumor effects of butyrate in tumor-bearing nude mice were evaluated. We found, butyrate significantly prevented GC cell proliferation, migration, and invasion (p < .01). Additionally, butyrate markedly inhibited GC cell aerobic glycolysis, as shown by the reduced expressions of GLUT1, HK2, and LDHA (p < .01). Moreover, butyrate notably decreased nuclear β-catenin and c-Myc levels in GC cells (p < .01). Remarkably, through activating Wnt/β-catenin signaling with LiCl, the inhibitory effects of butyrate on the growth and aerobic glycolysis of GC cells were diminished (p < .01). Moreover, butyrate notably suppressed tumor volume and weight in GC cell xenograft nude mice in vivo (p < .01). Meanwhile, butyrate obviously reduced nuclear β-catenin, c-Myc, GLUT1, HK2 and LDHA levels in tumor tissues in GC cell xenograft mice (p < .01). Collectively, butyrate could suppress the growth and aerobic glycolysis of GC cells in vitro and in vivo via downregulating wnt/β-catenin/c-Myc signaling. These findings are likely to prove useful in better understanding the role of butyrate in GC.

MECP2 promotes the migration and invasion of gastric cancer cells by modulating the Notch1/c-Myc/mTOR signaling pathways by suppressing FBXW7 transcription

Methyl-CpG-binding protein 2 (MECP2), an epigenetic regulatory factor, promotes the carcinogenesis and progression of a number of cancers. However, its role in the migration and invasion of gastric cancer (GC), as well as the underlying molecular mechanisms, remain unclear. In this study, we found that MECP2 promoted the migration, invasion and metastasis of GC cells. Investigation of the molecular mechanism revealed that MECP2 repressed F-box and WD40 domain protein 7 (FBXW7) transcription in GC by binding to the methylated CpG sites in the FBXW7 promoter region. MECP2 expression was markedly negatively correlated with the FBXW7 level in GC tissues. FBXW7 expression was significantly downregulated in GC tissues and cell lines, and low FBXW7 expression was correlated with unfavorable clinicopathologic features. FBXW7 inhibited cell migration and invasion by regulating the Notch1/c-Myc/mTOR signaling pathways, and knockdown of FBXW7 reversed the effects of silencing MECP2. Moreover, MECP2 upregulated the Notch1/c-Myc/mTOR signaling pathways by inhibiting FBXW7 expression at the transcriptional level. This study demonstrates that MECP2 promotes the migration and invasion of GC cells by modulating the Notch1/c-Myc/mTOR signaling pathways via suppression of FBXW7 transcription. These findings suggest that MECP2 may be a novel effective therapeutic target in GC.

Bioinformatics analysis of prognostic value and immunological role of MeCP2 in pan-cancer

Methyl-CpG-binding protein 2(MeCP2) is an important epigenetic regulatory factor that promotes many tumor developments, such as liver cancer, breast cancer, and colorectal cancer. So far, no pan-cancer analysis has been reported. Therefore, this study aims to explore pan-cancer's prognostic value, immune infiltration pattern, and biological function. We used bioinformatics methods to analyze the expression and prognostic significance of MeCP2, and the relationship between MeCP2 and clinicopathological parameters, genetic variation, methylation, phosphorylation, immune cell infiltration, and biological function in pan-cancer from using a public database. The results showed that expression of MeCP2 was up-regulated in 8 cancers and down-regulated in 2 cancers, which was remarkably correlated with the prognosis, pathological stage, grade and subtype of cancers. The promoter methylation level of MeCP2 DNA was decreased in bladder urothelial carcinoma (BLCA), breast invasive carcinoma (BRCA), liver hepatocellular carcinoma (LIHC), prostate adenocarcinoma (PRAD), uterine corpus endometrial carcinoma (UCEC), testicular germ cell tumors (TGCT), and stomach adenocarcinoma (STAD);decreased phosphorylation of S25, S90, S92, S241, S286, S325 and S435 was found in MeCP2, such as UCEC, lung adenocarcinoma (LUAD), ovarian serous cystadenocarcinoma (OV), colon adenocarcinoma (COAD), and kidney renal clear cell carcinoma (KIRC). Furthermore, MeCP2 expression was significantly associated with multiple immunomodulators and immune cell infiltration levels across most tumors. Therefore, our pan-cancer explored the prognostic markers and immunotherapeutic value of MeCP2 in different cancers.

HECTD3 promotes NLRP3 inflammasome and pyroptosis to exacerbate diabetes-related cognitive impairment by stabilising MALT1 to regulate JNK pathway

BACKGROUND

HECTD3 (HECT domain E3 ubiquitin protein ligase 3) exerts biological activities in neuroinflammation of distinct diseases, such as autoimmune encephalomyelitis and donations after heart death. However, the effect of HECTD3 on diabetes-associated cognitive decline (DACD) remains unclear.

METHODS

Wild-type or HECTD3-knockout rats were administered with streptozotocin to establish diabetic model. Pathological changes in the hippocampus were assessed by NISSL and haematoxylin and eosin staining. Morris water maze test was used to assess cognitive function. Neuronal survival and inflammation were investigated by immunofluorescence staining and ELISA assay. NLRP3 inflammasome and pyroptosis were assessed by western blot, immunofluorescence and flow cytometry assays.

RESULTS

HECTD3 was up-regulated in hippocampus of streptozotocin-induced diabetic rats and high glucose-induced PC12 cells. Knockout of HECTD3 increased the number of neurons and improved the learning and memory function. Moreover, knockout of HECTD3 promoted in vivo neuronal survival, and reduced levels of IL-1β, TNF-α, and IL-6 in the hippocampus. Silencing of HECTD3 increased cell viability, and reduced IL-1β, TNF-α, and IL-6 in high glucose-induced PC12 cells. Fluorescence intensities of NLRP3, GSDMD-N and caspase-1 were reduced in HECTD3-knockout diabetic rats, and knockdown of HECTD3 down-regulated protein expression of NLRP3, GSDMD-N, caspase-1, IL-1β, and IL-18 in high glucose-induced PC12 cells to suppress the pyroptosis. HECTD3 promoted the stability of mucosa-associated lymphoid tissue 1 (MALT1) through up-regulation of c-JUN and phospho (p)-JNK in high glucose-induced PC12 cells. Over-expression of MALT1 attenuated neuroprotective effects of HECTD3 silencing on high glucose-induced PC12 cells.

CONCLUSION

HECTD3 silencing exerted neuroprotective effect against DACD through MALT1-mediated JNK signalling.HighlightsHECTD3 was up-regulated in hippocampus of streptozotocin-induced diabetic rats and high glucose-induced PC12.Knockout of HECTD3 promoted in vivo neuronal survival, reduced inflammation and pyroptosis, and improved the learning and memory function in diabetic rats.Knockout of HECTD3 suppressed the activation of NLRP3 inflammasome in diabetic rats.Silencing of HECTD3 exerted neuroprotective effects through MALT1-mediated JNK signalling.

Berberine retarded the growth of gastric cancer xenograft tumors by targeting hepatocyte nuclear factor 4α

BACKGROUND

Gastric cancer is the third deadliest cancer in the world and ranks second in incidence and mortality of cancers in China. Despite advances in prevention, diagnosis, and therapy, the absolute number of cases is increasing every year due to aging and the growth of high-risk populations, and gastric cancer is still a leading cause of cancer-related death. Gastric cancer is a consequence of the complex interaction of microbial agents, with environmental and host factors, resulting in the dysregulation of multiple oncogenic and tumor-suppressing signaling pathways. Global efforts have been made to investigate in detail the genomic and epigenomic heterogeneity of this disease, resulting in the identification of new specific and sensitive predictive and prognostic biomarkers. Trastuzumab, a monoclonal antibody against the HER2 receptor, is approved in the first-line treatment of patients with HER2+ tumors, which accounts for 13%-23% of the gastric cancer population. Ramucirumab, a monoclonal antibody against VEGFR2, is currently recommended in patients progressing after first-line treatment. Several clinical trials have also tested novel agents for advanced gastric cancer but mostly with disappointing results, such as anti-EGFR and anti-MET monoclonal antibodies. Therefore, it is still of great significance to screen specific molecular targets for gastric cancer and drugs directed against the molecular targets.

AIM

To investigate the effect and mechanism of berberine against tumor growth in gastric cancer xenograft models and to explore the role of hepatocyte nuclear factor 4α (HNF4α)-WNT5a/β-catenin pathways played in the antitumor effects of berberine.

METHODS

MGC803 and SGC7901 subcutaneous xenograft models were established. The control group was intragastrically administrated with normal saline, and the berberine group was administrated intragastrically with 100 mg/kg/d berberine. The body weight of nude mice during the experiment was measured to assess whether berberine has any adverse reaction. The volume of subcutaneous tumors during this experiment was recorded to evaluate the inhibitory effect of berberine on the growth of MGC803 and SGC7901 subcutaneous transplantation tumors. Polymerase chain reaction assays were conducted to evaluate the alteration of transcriptional expression of HNF4α, WNT5a and β-catenin in tumor tissues and liver tissues from the MGC803 and SGC7901 xenograft models. Western blotting and IHC were performed to assess the protein expression of HNF4α, WNT5a and β-catenin in tumor tissues and liver tissues from the MGC803 and SGC7901 xenograft models.

RESULTS

In the both MGC803 and SGC7901 xenograft tumor models, berberine significantly reduced tumor volume and weight and thus retarded the growth rate of tumors. In the SGC7901 and MGC803 subcutaneously transplanted tumor models, berberine down-regulated the expression of HNF4α, WNT5a and β-catenin in tumor tissues from both transcription and protein levels. Besides, berberine also suppressed the protein expression of HNF4α, WNT5a and β-catenin in liver tissues.

CONCLUSION

Berberine retarded the growth of MGC803 and SGC7901 xenograft model tumors, and the mechanism behind these anti-growth effects might be the downregulation of the expression of HNF4α-WNT5a/β-catenin signaling pathways both in tumor tissues and liver tissues of the xenograft models.

MeCP2 Increases Cisplatin Resistance in Human Gastric Cancer through the Activation of the AKT Pathway by Facilitating PDK-1 Transcription

BACKGROUND

Increasing evidence indicates that an imbalance of oncogenes is implicated in chemotherapy resistance in cancers. Methyl-CpG binding protein 2 (MeCP2), which acts as a master epigenetic regulator of various gene expressions, is involved in the carcinogenesis and progression of gastric cancer. However, whether this vital role may participates in acquired cisplatin resistance in GC remains unknown.

OBJECTIVE

This study aimed to determine whether inhibition of MeCP2 expression could sensitize DDP-resistant GC cells to DDP and to elucidate its underlying molecular mechanism.

METHODS

qRT-PCR and western blotting were used to evaluate MeCP2 expression in GC DDP-resistant GC cells. Subsequently, cell viability, colony formation, cell cycle, cell apoptosis and tumorigenicity assays were performed to explore the role of MeCP2 in vitro and in vivo. Chromatin immunoprecipitation-qPCR and luciferase reporter assays were used to identify whether 3-phosphoinositide-dependent protein kinase 1 (PDK-1) is a direct target gene of MeCP2.

RESULTS

MeCP2 was upregulated in malignant DDP-resistant cells compared to that in non-DDP-resistant GC cells or normal gastric epithelial cells. MeCP2 knockdown increased the sensitivity of DDP-resistant GC cells to DDP, resulting in reduced cell growth, G0/G1 phase arrest and increased apoptosis, wheras MeCP2 overexpression attenuated DDP sensitivity of DDP-resistant GC cells. In addition, MeCP2 knockdown enhanced DDP sensitivity in tumors in vivo. MeCP2 elevated PDK-1 expression by binding to its CpG sites in promoter regions, and inhibition of PDK-1 reversed the inductive effect of MeCP2 overexpression on DDP resistance in GC cells.

CONCLUSION

These findings indicate that silencing MeCP2 may potentiate DDP induced cell death, providing a promising therapeutic strategy for GC.

MeCP2 confers 5-fluorouracil resistance in gastric cancer via upregulating the NOX4/PKM2 pathway

Background

Increasing evidence suggests that aberrant methylation is involved in 5-fluorouracil (5-FU) resistance in gastric cancer (GC). Our previous work has identified that Methyl-CpG binding protein 2 (MeCP2) promotes GC progression by binding to the methylation sites of promoter regions of specific genes to affect the downstream signaling pathways. However, the function and molecular mechanisms of MeCP2 in GC 5-FU resistance remain unclear.

Methods

We detected the expression of MeCP2 in 5-FU-resistant GC cells and examined cell behaviors when MeCP2 was silenced. The molecular mechanisms were explored through chromatin immunoprecipitation (ChIP)-qRT-PCR, luciferase reporter assay, clinical tissue samples analysis, and in vivo tumorigenicity assay.

Results

MeCP2 was up-regulated in 5-FU-resistant GC cells. Knockdown of MeCP2 enhanced the sensitivity of the cells to 5-FU. Moreover, MeCP2 promoted NOX4 transcription in the cells by binding to the promoter of NOX4. Silencing NOX4 rescued the inductive effect of MeCP2 overexpression on 5-FU sensitivity of GC cells and reduced the expression of NOX4 and PKM2 in MeCP2 overexpressed 5-FU-resistant GC cells. In addition, our in vivo experiments demonstrated that MeCP2 knockdown enhanced 5-FU sensitivity in tumors.

Conclusion

MeCP2 confers 5-FU resistance in GC cells via upregulating the NOX4/PKM2 pathway, which may lead to a promising therapeutic strategy for GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02489-y.

The novel lncRNA GPC5-AS1 stabilizes GPC5 mRNA by competitively binding with miR-93/106a to suppress gastric cancer cell proliferation

Long non-coding RNAs (lncRNAs) are of importance in the genesis and progression of gastric cancer (GC). GPC5-AS1 is a novel lncRNA associated with methyl-CpG-binding protein 2 (MeCP2), identified in our previous microarray analysis; however, the role of GPC5-AS1 in GC remains unknown. In the present study, we demonstrate that GPC5-AS1 is downregulated in GC cells and tissues, and this aberrant expression is regulated by MeCP2 through CpG site binding in the promoter region. Importantly, we also demonstrate that GPC5-AS1 overexpression suppresses cell proliferation, colony formation, and cell cycle transition; induces apoptosis in vitro; and inhibits tumorigenicity in vivo. The expression of the controversial gene GPC5 was downregulated in GC tissues, and elevated GPC5 level could inhibit GC cell growth. Mechanistically, we demonstrated that GPC5-AS1 stabilizes GPC5 mRNA by acting as a molecular sponge for miR-93 and miR-106a, thereby reducing GC tumor progression. In conclusion, our results suggest that GPC5-AS1 may play a pivotal role in GC and serve as a potential diagnostic biomarker and a powerful therapeutic target for GC.

The LncRNA DUXAP10 Could Function as a Promising Oncogene in Human Cancer

Cancer is one of the most prevalent and deadliest diseases globally, with an increasing morbidity of approximately 14 million new cancer cases per year. Identifying novel diagnostic and prognostic biomarkers for cancers is important for developing cancer therapeutic strategies and lowering mortality rates. Long noncoding RNAs (lncRNAs) represent a group of noncoding RNAs of more than 200 nucleotides that have been shown to participate in the development of human cancers. The novel lncRNA DUXAP10 was newly reported to be abnormally overexpressed in several cancers and positively correlated with poor clinical characteristics of cancer patients. Multiple studies have found that DUXAP10 widely regulates vital biological functions related to the development and progression of cancers, including cell proliferation, apoptosis, invasion, migration, and stemness, through different molecular mechanisms. The aim of this review was to recapitulate current findings regarding the roles of DUXAP10 in cancers and evaluate the potential of DUXAP10 as a novel biomarker for cancer diagnosis, treatment, and prognostic assessment.

Foxf1 gene increases the risk of osteoporosis in rats by inhibiting osteoblast formation and promoting osteoclast differentiation through the upregulation of NF-κB pathway

OBJECTIVES

a) To explore the expression of Foxf1 and NF-κB in bone tissue of ovariectomized rats with osteoporosis and b) to investigate the role and mechanism of NF-κB pathway regulated by Foxf1 gene in the differentiation and formation of rat osteoclasts and osteoblasts with cell experiments.

METHODS

Ovariectomized rat model of osteoporosis was established with 3-month-old female SD rats. The rats were divided into sham group (n=10) and osteoporosis group (n=10). Real time fluorescent quantitative PCR and Western blot were used to detect the expression levels of Foxf1 and NF-κB genes and proteins in the femur tissues of rats and analyze their correlation.

RESULTS

Both Foxf1 and NF- κB were highly expressed in the femur tissues. Upon the overexpression of Foxf1 gene in osteoblasts and osteoclasts in vitro, the gene and protein expression of NF-κB were also upregulated, significantly reducing the gene and protein expression levels of osteogenic factors, including ATF4, OCN, ALP and Runx2.

CONCLUSIONS

Foxf1 gene could inhibit osteoblast formation and promote osteoclast differentiation by NF-κB pathway, which may increase the risk of osteoporosis in rats.

Methyl-CpG-binding protein 2 promotes osteogenic differentiation of bone marrow mesenchymal stem cells through regulating forkhead box F1/Wnt/β-Catenin axis

Postmenopausal osteoporosis is characterized by inadequate bone formation of osteoblasts and excessive bone resorption of osteoclasts. Bone marrow mesenchymal stem cells (BMSCs), with the potential of osteogenic differentiation, have been widely used in the bone tissues engineering for the treatment of bone diseases, including postmenopausal osteoporosis. Methyl-CpG-binding protein 2 (MECP2) has been reported to be implicated in bone formation during the development of Rett syndrome. However, the influence of MeCP2 on osteogenic differentiation of BMSCs during osteoporosis remains unclear. Firstly, mice model with estrogen deficiency-induced osteoporosis was established through ovariectomy (OVX). MeCP2 was found to be down-regulated in bone tissues and BMSCs of OVX-induced osteoporosis mice. Secondly, over-expression of MeCP2 enhanced the calcium deposition of BMSCs isolated from the OVX-induced osteoporosis mice. Moreover, expression of osteogenic biomarkers including alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), collagen type I alpha 1 (COL1A1), and osteocalcin (OCN) was increased in BMSCs by overexpression of MeCP2. Thirdly, over-expression of MeCP2 reduced protein expression of forkhead box F1 (FOXF1) and adenomatous polyposis coli (APC), while enhanced Wnt5a and β-catenin expression in BMSCs. Over-expression of FOXF1 attenuated MeCP2 over-expression-induced decrease of FOXF1 and APC, as well as increase of Wnt5a and β-catenin. Finally, the increased calcium deposition, protein expression of ALP, RUNX2COL1A1 and OCN induced by concomitant overexpression of MeCP2 were also restored by FOXF1 over-expression. In conclusion, MeCP2 promoted osteogenic differentiation of BMSCs through regulating FOXF1/Wnt/β-Catenin axis to attenuate osteoporosis. MeCP2 over-expression reduced FOXF1 to promote the activation of Wnt5a/β-Catenin and promote osteogenic differentiation of BMSCs during the prevention of postmenopausal osteoporosis.

MeCP2 drives hepatocellular carcinoma progression via enforcing HOXD3 promoter methylation and expression through the HB-EGF/EGFR pathway

Homeobox D3 (HOXD3), a member of the homeobox family, was described to regulate tumorigenesis, invasion, metastasis, and angiogenesis in various tumor types. However, the molecular mechanisms regulating HOXD3 during hepatocellular carcinoma (HCC) migration, invasion, and angiogenesis remain elusive. In this study, we demonstrated that HOXD3 expression is enhanced by the binding of methyl-CpG-binding protein 2 (MeCP2), a methyl-CpG binding protein, together with CREB1to the hypermethylated promoter of HOXD3. Inhibition of HOXD3 eliminated the tumorigenic effects of MeCP2 on HCC cells. Furthermore, HOXD3 directly targeted the promoter region of heparin-binding epidermal growth factor (HB-EGF) via the EGFR-ERK1/2 cell signaling pathway and promoted invasion, metastasis, and angiogenesis of HCC in vitro and in vivo. Additionally, elevated expression of MeCP2, CREB1, and HB-EGF in HCC correlated with a poor survival rate. Our findings reveal the function of the MeCP2/HOXD3/HB-EGF regulatory axis in HCC, rendering it an attractive candidate for the development of targeted therapeutics and as a potential biomarker in patients with HCC.

Therapeutic Mechanism of Lapatinib Combined with Sulforaphane on Gastric Cancer

Background

Lapatinib is a small-molecule tyrosine kinase inhibitor that plays important roles in cell proliferation and survival. Administration of lapatinib with capecitabine is an effective treatment for HER2-positive metastatic BC. However, the effects of lapatinib on gastric cancer (GC) remain to be clear. In this study, we aimed to investigate the therapeutic effects of lapatinib combined with sulforaphane on GC and its underlying mechanisms.

Methods

SGC-7901 and lapatinib-resistant SGC-7901 cells were treated with lapatinib (0.2 μM), sulforaphane (5 μM), or their combinations. Cell viability, invasion, cycle, and apoptosis of SGC-7901 and lapatinib-resistant SGC-7901 cells were evaluated by thiazolyl blue tetrazolium bromide (MTT), Boyden chamber assay, and flow cytometer. The protein expressions of HER-2, p-HER-2, AKT, p-AKT, ERK, and p-ERK were detected by Western blotting.

Results

We observed that lapatinib combined with sulforaphane significantly decreased cell viability and inhibited cell migration of drug-sensitive and drug-resistant cells. Lapatinib sulforaphane also remarkably induced cell apoptosis with G0/G1 arrest. In addition, Western blotting revealed that the expressions of HER-2, p-HER-2, AKT, p-AKT, ERK, and p-ERK were downregulated by lapatinib-sulforaphane treatment.

Conclusion

Combination of lapatinib and sulforaphane might be a novel and promising therapeutic treatment for lapatinib-sensitive or lapatinib-resistant GC patients.

MYOD1 as a prognostic indicator in rhabdomyosarcoma

BACKGROUND/OBJECTIVES

Rhabdomyosarcoma (RMS) is characterized by the expression of the myogenic regulatory protein MYOD1. Histologic types include alveolar, embryonal (ERMS), and spindle cell sclerosing RMS (SRMS). SRMS harbors MYOD1 mutations in a subset of adult cases in association with poor prognosis.

DESIGN/METHODS

To study the level of MYOD1 protein expression and its clinical significance, we have analyzed variable numbers of pediatric (<18 years of age) and adult (age range ≥18 to 35 years) ERMS and SRMS cases for presence or absence of MYOD1 immunoreactivity in correlation with clinical outcome and MYOD1 L122R mutations.

RESULTS

Lack of MYOD1 immunoreactivity, identified in 23.8% of nonalveolar RMS (non-ARMS) cases, was more prevalent in SRMS (44%) than ERMS (17.2%) and was significantly associated with low overall survival and unfavorable tumor sites (p < .05). Lack of MYOD1 immunoreactivity was not associated with MYOD1 L122R mutations, which were identified in 3/37 (8%) cases including only two of 31 (6.5%) pediatric cases, one of 11 or 9% pediatric SRMS, and one case of infant ERMS.

CONCLUSION

These studies highlight the prognostic role of MYOD1 in non-ARMS. Lack of MYOD1 immunoreactivity is associated with poor prognosis in ERMS and SRMS. MYOD1 gene mutations are generally infrequent in pediatric RMS. Although mutations are predominant in SRMS, they may exceptionally occur in infantile ERMS.

Neutralization of the induced VEGF-A potentiates the therapeutic effect of an anti-VEGFR2 antibody on gastric cancer in vivo

The vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) axis is an essential regulator of angiogenesis and important therapeutic target in cancer. Ramucirumab is an anti-VEGFR2 monoclonal antibody used for the treatment of several cancers. Increased circulating VEGF-A levels after ramucirumab administration are associated with a worse prognosis, suggesting that excess VEGF-A induced by ramucirumab negatively affects treatment efficacy and that neutralizing VEGF-A may improve treatment outcomes. Here, we evaluated the effect of combination treatment with an anti-VEGFR2 antibody and anti-VEGF-A antibody on gastric tumor progression and normal tissues using a preclinical BALB/c-nu/nu mouse xenograft model. After anti-VEGFR2 antibody treatment in mice, a significant increase in plasma VEGF-A levels was observed, mirroring the clinical response. The elevated VEGF-A was host-derived. Anti-VEGF-A antibody co-administration enhanced the anti-tumor effect of the anti-VEGFR2-antibody without exacerbating the toxicity. Mechanistically, the combination treatment induced intra-tumor molecular changes closely related to angiogenesis inhibition and abolished the gene expression changes specifically induced by anti-VEGFR2 antibody treatment alone. We particularly identified the dual treatment-selective downregulation of ZEB1 expression, which was critical for gastric cancer cell proliferation. These data indicate that the dual blockade of VEGF-A and VEGFR2 is a rational strategy to ensure the anti-tumor effect of angiogenesis-targeting therapy.

Methyl CpG binding protein 2 promotes colorectal cancer metastasis by regulating N6 -methyladenosine methylation through methyltransferase-like 14

RNA N⁶‐methyladenosine (m⁶A) is an emerging regulatory mechanism for tumor progression in several types of cancer. However, the underlying regulation mechanisms of m⁶A methylation in colorectal cancer (CRC) remain unknown. Although the oncogenic function of methyl CpG binding protein 2 (MeCP2) has been reported, it is still unclear whether MeCP2 could alter RNA m⁶A methylation state. Here, we systematically identified MeCP2 as a prometastasis gene to regulate m⁶A methylation in CRC. Interestingly, MeCP2 could bind to methyltransferase‐like 14 (METTL14) to coregulate tumor suppressor Kruppel‐like factor 4 (KLF4) expression through changing m⁶A methylation modification. Furthermore, insulin‐like growth factor 2 mRNA‐binding protein 2 recognized the unique modified m⁶A methylation sites to enhance KLF4 mRNA stability. Taken together, these findings highlight the novel function of MeCP2 for regulating m⁶A methylation and reveal the underlying molecular mechanism for the interaction between MeCP2 and METTL14, which offers a better understanding of CRC progression and metastasis.

WNT5A inhibition alters the malignant peripheral nerve sheath tumor microenvironment and enhances tumor growth

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft-tissue sarcomas that cause significant mortality in adults with neurofibromatosis type 1. We compared gene expression of growth factors in normal human nerves to MPNST and normal human Schwann cells to MPNST cell lines. We identified WNT5A as the most significantly upregulated ligand-coding gene and verified its protein expression in MPNST cell lines and tumors. In many contexts WNT5A acts as an oncogene. However, inhibiting WNT5A expression using shRNA did not alter MPNST cell proliferation, invasion, migration, or survival in vitro. Rather, shWNT5A-treated MPNST cells upregulated mRNAs associated with the remodeling of extracellular matrix and with immune cell communication. In addition, these cells secreted increased amounts of the proinflammatory cytokines CXCL1, CCL2, IL6, CXCL8, and ICAM1. Versus controls, shWNT5A-expressing MPNST cells formed larger tumors in vivo. Grafted tumors contained elevated macrophage/stromal cells, larger and more numerous blood vessels, and increased levels of Mmp9, Cxcl13, Lipocalin-1, and Ccl12. In some MPNST settings, these effects were mimicked by targeting the WNT5A receptor ROR2. These data suggest that the non-canonical Wnt ligand WNT5A inhibits MPNST tumor formation by modulating the MPNST microenvironment, so that blocking WNT5A accelerates tumor growth in vivo.

FAM196B promotes proliferation and migration via regulating epithelial-mesenchymal transition in esophageal cancer

BACKGROUND

EC (esophageal cancer) is a common cancer among people in the world. The molecular mechanism of FAM196B (family with sequence similarity 196 member B) in EC is still unclear. This article aimed to clarify the role of FAM196B in EC.

METHODS

The expression of FAM196B in EC tissues was detected using qRT-PCR. The prognosis of FAM196B in EC patients was determined by log-rank kaplan-Meier survival analysis and Cox regression analysis. Furthermore, shRNA was used to knockdown the expression of FAM196B in EC cell lines. MTT, wound healing assays and western blot were used to determine the role of FAM196B in EC cells.

RESULTS

In our research, we found that the expression of FAM196B was up-regulated in EC tissues. The increased expression of FAM196B was significantly correlated with differentiation, lymph node metastasis, stage, and poor survival. The proliferation and migration of EC cells were inhibited after FAM196B-shRNA transfection in vitro and vivo. The western blot result showed that FAM196B could regulate EMT.

CONCLUSION

These results suggested that FAM196B severs as an oncogene and promotes cell proliferation and migration in EC. In addition, FAM196B may be a potential therapeutic target for EC patients.

MBNL1 Suppressed Cancer Metastatic of Skin Squamous Cell Carcinoma Via by TIAL1/MYOD1/Caspase-9/3 Signaling Pathways

OBJECTIVE

The incidence of skin squamous cell carcinoma (SSCC) has recently been increasing, with diverse clinical manifestations.SSCC could metastasize to lymph nodes or other organs, posing a great threat to life. The present study was designed to investigate the function and underlying mechanism of muscleblind-like protein 1 (MBNL1) in skin squamous cell carcinoma.

METHODS

SCL-1 cell was used for vitro model and transfected with MBNL1 or siMBNL1 plasmids. MTT Assays, LDH activity ELISA, and Transwell chamber migration experiment were used to confirm the effects of MBNL1 on cell growth of SCL-1 cell. Western blot analysis was used to analyze the mechanism of MBNL1 in SCL-1 cell.

RESULTS

Down-regulation of MBNL1 promoted cell metastasis of SSCC, while up-regulation of MBNL1 reduced cell metastasis of SSCC in vitro. Down-regulation of MBNL1 suppressed the protein expression of T cell intracellular antigen (TIAL1), myogenic determinant 1 (MyoD1) and Caspase-3 in vitro. Consistent with these observations, inhibition of TIAL1 or MYOD1 expression attenuated the effects of MBNL1 in SSCC.

CONCLUSION

The present study revealed that MBNL1 suppressed thecancer metastatic capacity of SSCC via by TIAL1/MYOD1/Caspase-3 signaling pathways.

Functional vinorelbine plus schisandrin B liposomes destroying tumor metastasis in treatment of gastric cancer

Gastric cancer is one of the leading causes of cancer-related death worldwide with a poor prognosis. Gastric cancer is usually treated with surgery and chemotherapy, accompanied by a high rate of metastasis and recurrence. In this paper, R₈ (RRRRRRRR) modified vinorelbine plus schisandrin B liposomes had been successfully constructed for treating gastric cancer. In the liposomes, R₈ was used to enhance the intracellular uptake, schisandrin B was incorporated into liposomes for inhibiting tumor cells metastasis, and vinorelbine was encapsulated into liposomes as antitumor drugs. Studies were performed on BGC-823 cells in vitro and were verified in the BGC-823 cell xenografts nude mice in vivo. Results in vitro demonstrated that the targeting liposomes could induce BGC-823 cells apoptosis, inhibit the metastasis of tumor cells, and increase targeting effects to tumor cells. Meanwhile, action mechanism studies showed that the targeting liposomes could down-regulate VEGF, VE-Cad, HIF-1a, PI3K, MMP-2, and FAK to inhibit tumor metastasis. In vivo results exhibited that the targeting liposomes displayed an obvious antitumor efficacy by accumulating selectively in tumor site and induce tumor cell apoptosis. Hence, R₈ modified vinorelbine plus schisandrin B liposomes might provide a safe and efficient therapy strategy for gastric cancer.

Identification of Novel MeCP2 Cancer-Associated Target Genes and Post-Translational Modifications

Abnormal regulation of DNA methylation and its readers has been associated with a wide range of cellular dysfunction. Disruption of the normal function of DNA methylation readers contributes to cancer progression, neurodevelopmental disorders, autoimmune disease and other pathologies. One reader of DNA methylation known to be especially important is MeCP2. It acts a bridge and connects DNA methylation with histone modifications and regulates many gene targets contributing to various diseases; however, much remains unknown about how it contributes to cancer malignancy. We and others previously described novel MeCP2 post-translational regulation. We set out to test the hypothesis that MeCP2 would regulate novel genes linked with tumorigenesis and that MeCP2 is subject to additional post-translational regulation not previously identified. Herein we report novel genes bound and regulated by MeCP2 through MeCP2 ChIP-seq and RNA-seq analyses in two breast cancer cell lines representing different breast cancer subtypes. Through genomics analyses, we localize MeCP2 to novel gene targets and further define the full range of gene targets within breast cancer cell lines. We also further examine the scope of clinical and pre-clinical lysine deacetylase inhibitors (KDACi) that regulate MeCP2 post-translationally. Through proteomics analyses, we identify many additional novel acetylation sites, nine of which are mutated in Rett Syndrome. Our study provides important new insight into downstream targets of MeCP2 and provide the first comprehensive map of novel sites of acetylation associated with both pre-clinical and FDA-approved KDACi used in the clinic. This report examines a critical reader of DNA methylation and has important implications for understanding MeCP2 regulation in cancer models and identifying novel molecular targets associated with epigenetic therapies.

MiR-22, regulated by MeCP2, suppresses gastric cancer cell proliferation by inducing a deficiency in endogenous S-adenosylmethionine

This study investigated the effect of methyl-CpG-binding protein 2 (MeCP2) on miRNA transcription. Our results of miRNA chip assay and ChIP-seq showed that MeCP2 inhibited the expressions of numerous miRNAs by binding to their upstream elements, including not only the promoter but also the distal enhancer. Among the affected miRNAs, miR-22 was identified to remarkably suppress gastric cancer (GC) cell proliferation, arrest G1-S cell cycle transition, and induce cell apoptosis by targeting MeCP2, MTHFD2, and MTHFR. Understanding GC metabolism characteristics is the key to developing novel therapies that target GC metabolic pathways. Our study revealed that the metabolic profiles in GC tissues were altered. SAM (S-adenosylmethionine), a universal methyl donor for histone and DNA methylation, which is specifically involved in the epigenetic maintenance of cancer cells, was found increased. The production of SAM is promoted by the folate cycle. Knockdown of MTHFD2 and MTHFR, two key enzymes in folate metabolism and methyl donor SAM production, significantly suppressed GC cell proliferation. MiR-22 overexpression reduced the level of endogenous SAM by suppressing MTHFD2 and MTHFR, inducing P16, PTEN, and RASSF1A hypomethylation. In conclusion, our study suggests that miR-22 was inhibited by MeCP2, resulting in deficiency of endogenous SAM, and ultimately leading to tumor suppressor dysregulation.

Marek's Disease Virus (Gallid alphaherpesvirus 2)-Encoded miR-M2-5p Simultaneously Promotes Cell Proliferation and Suppresses Apoptosis Through RBM24 and MYOD1-Mediated Signaling Pathways

MicroRNAs (miRNAs) have been demonstrated for their involvement in virus biology and pathogenesis, including functioning as key determinants of virally-induced cancers. As an important oncogenic α-herpesvirus affecting poultry health, Marek’s disease virus serotype 1 [Gallid alphaherpesvirus 2 (GaHV-2)] induces rapid-onset T-cell lymphomatous disease commonly referred to as Marek’s disease (MD), an excellent biological model for the study of virally-induced cancer in the natural hosts. Previously, we have demonstrated that GaHV-2-encoded miRNAs (especially those within the Meq-cluster) have the potential to act as critical regulators of multiple processes such as virus replication, latency, pathogenesis, and/or oncogenesis. In addition to miR-M4-5p (miR-155 homolog) and miR-M3-5p, we have recently found that miR-M2-5p possibly participate in inducing MD lymphomagenesis. Here, we report the identification of two tumor suppressors, the RNA-binding protein 24 (RBM24) and myogenic differentiation 1 (MYOD1), being two biological targets for miR-M2-5p. Our experiments revealed that as a critical miRNA, miR-M2-5p promotes cell proliferation via regulating the RBM24-mediated p63 overexpression and MYOD1-mediated IGF2 signaling and suppresses apoptosis by targeting the MYOD1-mediated Caspase-3 signaling pathway. Our data present a new strategy of a single viral miRNA exerting dual role to potentially participate in the virally-induced T-cell lymphomagenesis by simultaneously promoting the cell proliferation and suppressing apoptosis.

Multifaceted behavior of PEST sequence enriched nuclear proteins in cancer biology and role in gene therapy

The amino acid sequence enriched with proline (P), glutamic acid (E), serine (S), and threonine (T) (PEST) is a signal-transducing agent providing unique features to its substrate nuclear proteins (PEST-NPs). The PEST motif is responsible for particular posttranslational modifications (PTMs). These PTMs impart distinct properties to PEST-NPs that are responsible for their activation/inhibition, intracellular localization, and stability/degradation. PEST-NPs participate in cancer metabolism, immunity, and protein transcription as oncogenes or as tumor suppressors. Gene-based therapeutics are getting the attention of researchers because of their cell specificity. PEST-NPs are good targets to explore as cancer therapeutics. Insights into PTMs of PEST-NPs demonstrate that these proteins not only interact with each other but also recruit other proteins to/from their active site to promote/inhibit tumors. Thus, the role of PEST-NPs in cancer biology is multivariate. It is hard to obtain therapeutic objectives with single gene therapy. An especially designed combination gene therapy might be a promising strategy in cancer treatment. This review highlights the multifaceted behavior of PEST-NPs in cancer biology. We have summarized a number of studies to address the influence of structure and PEST-mediated PTMs on activation, localization, stability, and protein-protein interactions of PEST-NPs. We also recommend researchers to adopt a pragmatic approach in gene-based cancer therapy.

Silencing miR-454 suppresses cell proliferation, migration and invasion via directly targeting MECP2 in renal cell carcinoma

Renal cell cancer (RCC) is one of the most common malignant tumors of the urinary system. MicroRNA-454 (miR-454) has been reported to play an important role in various cancer progressions, such as hepatocellular carcinoma, breast cancer and glioblastoma. Nevertheless, its effect on RCC still remains unknown. We aimed to investigate the biological function and underlying mechanisms of miR-454 in RCC. The expressions of miR-454 and MECP2 in RCC tissues were assessed using data from TCGA database and our own clinical samples. Functional experiments Cell Counting Kit-8 (CCK-8), colony formation, wound healing and Transwell assays were applied to detect the effects of miR-454 and MECP2 in RCC. The interaction between miR-454 and MECP2 was assessed by western blot and luciferase reporter assays. MiR-454 was upregulated in RCC tissues and cell lines compared with matched adjacent normal tissues and the normal kidney tubular epithelial cell line HK-2. MiR-454 inhibition and methyl-CpG binding protein 2 (MECP2) overexpression could both decrease the proliferative, migrative and invasive abilities of RCC cells. Higher expression of miR-454 predicted a poor overall survival (OS) (HR: 1.8; P < 0.05), while MECP2 level was positively related with RCC OS (HR: 0.55; P < 0.05) and disease-free survival (HR: 0.56; P < 0.05). Mechanistically, we showed that miR-454 could directly target the downstream gene MECP2. Our findings indicated that miR-454 accelerates RCC progression via suppressing MECP2 expression, which may provide a novel potential target of RCC treatment in the future.

A genome-wide analysis reveals the MeCP2-dependent regulation of genes in BGC-823 cells

Methyl-CpG-binding protein 2 (MeCP2) epigenetically modulates gene expression through genome-wide binding to methylated CpG dinucleotides. This study aimed to evaluate the effect of MeCP2 on the global gene expression profile of human gastric adenocarcinoma to determine the potential molecular mechanism of MeCP2. To identify the gene targets of MeCP2 in gastric cancer cells, we combined the expression microarray and chromatin immunoprecipitation approaches of MeCP2, followed by sequencing (ChIP-seq) to define the MeCP2-binding sites across the whole genome. The methylation levels of the promoters in BGC-823 cells were downloaded from the National Center for Biotechnology Information Gene Expression Omnibus database (GSM1093053). A total of 5,684 ChIP-enriched peaks were identified by comparing IP and Input, using a p-value threshold of 10^-5 in ChIP-seq. The bioinformatics analysis presented a predictive model of the genome-wide MeCP2-binding pattern, in which the MeCP2 binding site is closely related to the transcription start site region in the genome. The results of motif detection showed that the MeCP2-binding regions contained not only the core CpG motif but also the extended poly (A/T) motifs. Finally, an integrative analysis of the sequence features and DNA methylation states revealed that MeCP2's function as a multifunctional transcriptional regulator may not be directly related to the methylation status of the binding site. The first MeCP2 ChIP-seq and gene expression microarray analysis in BGC-823 cells revealed that MeCP2 plays multiple roles in the regulation of gene expression depending on the microenvironment, such as sequence characteristics and the methylation levels of binding sites.

HOXD3 was negatively regulated by YY1 recruiting HDAC1 to suppress progression of hepatocellular carcinoma cells via ITGA2 pathway

Objectives

HOXD3 is associated with progression of multiple types of cancer. This study aimed to identify the association of YY1 with HOXD3‐ITGA2 axis in the progression of hepatocellular carcinoma.

Materials and Methods

Bioinformatics assay was used to identify the effect of YY1, HOXD3 and ITGA2 expression in HCC tissues. The function of YY1 and HOXD3 in HCCs was determined by qRT‐PCR, MTT, apoptosis, Western blotting, colony formation, immunohistochemistry, and wound‐healing and transwell invasion assays. The relationship between YY1 and HOXD3 or HOXD3 and ITGA2 was explored by RNA‐Seq, ChIP‐PCR, dual luciferase reports and Pearson's assays. The interactions between YY1 and HDAC1 were determined by immunofluorescence microscopy and Co‐IP.

Results

Herein, we showed that the expression of YY1, HOXD3 and ITGA2 associated with the histologic and pathologic stages of HCC. Moreover, YY1, recruiting HDAC1, can directly target HOXD3 to regulate progression of HCCs. The relationship between YY1 and HOXD3 was unknown until uncovered by our present investigation. Furthermore, HOXD3 bound to promoter region of ITGA2 and up‐regulated the expression, thus activating the ERK1/2 signalling and inducing HCCs proliferation, metastasis and migration in the vitro and vivo.

Conclusions

Therefore, HOXD3, a target of YY1, facilitates HCC progression via activation of the ERK1/2 signalling by promoting ITGA2. This finding provides a new whole way to HCC therapy by serving YY1‐HOXD3‐ITGA2 regulatory axis as a potential therapeutic target for HCC therapy.

MicroRNA-4268 inhibits cell proliferation via AKT/JNK signalling pathways by targeting Rab6B in human gastric cancer

MicroRNAs (miRNAs) play critical roles in the tumorigenesis and progression of gastric cancer (GC). However, the biological function of miR-4268 in GC and its mechanism remain unclear. In the present study, qTR-PCR found that the expression of miR-4268 was significantly downregulated in GC tissues and cell lines. The overexpression of miR-4268 inhibited GC cell proliferation and the cell cycle G1/S phase transition, and induced cell apoptosis. In contrast, inhibition of miR-4268 promoted cell proliferation and G1-S transition, and suppressed cell apoptosis. Further analyses revealed that miR-4268 expression was negatively correlated with Rab6B expression in GC tissues. Rab6B was verified to be a direct target of miR-4268. Notably, silencing Rab6B resulted in the same biological effects in GC cells as those induced by overexpression of miR-4268. Importantly, both miR-4268 overexpression and Rab6B silence inhibited the AKT/JNK signaling pathways, which modulated cell cycle regulators (Cyclin D1 and CDK4). In contrast, inhibition of miR-4268 promoted the AKT/JNK signaling pathways. MiR-4268 overexpression also promoted the p38 MAPK signaling pathway. Taken together, miR-4268 suppresses GC cell proliferation through inhibiting the AKT/JNK signaling pathways by targeting Rab6B and induces cell apoptosis through promoting the p38 MAPK signaling pathway. Our findings indicate a tumor-suppressor role of miR-4268 in GC pathogenesis and the potential of miR-4268 in GC theropy.

MeCP2 facilitates breast cancer growth via promoting ubiquitination-mediated P53 degradation by inhibiting RPL5/RPL11 transcription

Methyl-CpG-binding protein 2 (MeCP2) facilitates the carcinogenesis and progression of several types of cancer. However, its role in breast cancer and the relevant molecular mechanism remain largely unclear. In this study, analysis of the Cancer Genome Atlas (TCGA) data that MeCP2 expression was significantly upregulated in breast cancer tissues, and high MeCP2 expression was correlated with poor overall survival. Knockdown of MeCP2 inhibited breast cancer cell proliferation and G1–S cell cycle transition and migration as well as induced cell apoptosis in vitro. Moreover, MeCP2 knockdown suppressed cancer cell growth in vivo. Investigation of the molecular mechanism showed that MeCP2 repressed RPL11 and RPL5 transcription by binding to their promoter regions. TCGA data revealed significantly lower RPL11 and RPL5 expression in breast cancer tissues; additionally, overexpression of RPL11/RPL5 significantly suppressed breast cancer cell proliferation and G1–S cell cycle transition and induced apoptosis in vitro. Furthermore, RPL11 and RPL5 suppressed ubiquitination-mediated P53 degradation through direct binding to MDM2. This study demonstrates that MeCP2 promotes breast cancer cell proliferation and inhibits apoptosis through suppressing RPL11 and RPL5 transcription by binding to their promoter regions.

Differential brain region-specific expression of MeCP2 and BDNF in Rett Syndrome patients: a distinct grey-white matter variation

INTRODUCTION AND OBJECTIVES

Rett Syndrome (RTT) is a neurodevelopmental disorder caused by Methyl CpG Binding Protein 2 (MECP2) gene mutations. Previous studies of MeCP2 in the human brain showed variable and inconsistent mosaic-pattern immunolabelling, which has been interpreted as a reflection of activation-state variability. We aimed to study post mortem MeCP2 and BDNF (MeCP2 target) degradation and brain region-specific detection in relation to RTT pathophysiology.

METHODS

We investigated MeCP2 and BDNF stabilities in non-RTT human brains by immunohistochemical labelling and compared them in three brain regions of RTT and controls.

RESULTS

In surgically excised samples of human hippocampus and cerebellum, MeCP2 was universally detected. There was no significantly obvious difference between males and females. However, post mortem delay in autopsy samples had substantial influence on MeCP2 detection. Immunohistochemistry studies in RTT patients showed lower MeCP2 detection in glial cells of the white matter. Glial fibrillary acidic protein (GFAP) expression was also reduced in RTT brain samples without obvious change in myelin basic protein (MBP). Neurons did not show any noticeable decrease in MeCP2 detection. BDNF immunohistochemical detection showed an astroglial/endothelial pattern without noticeable difference between RTT and controls.

CONCLUSIONS

Our findings indicate that MeCP2 protein is widely expressed in mature human brain cells at all ages. However, our data points towards a possible white matter abnormality in RTT and highlights the importance of studying human RTT brain tissues in parallel with research on animal and cell models of RTT.

MeCP2 Promotes Colorectal Cancer Metastasis by Modulating ZEB1 Transcription

Background: Recurrence and distant organ metastasis is a major cause of death in colorectal cancer (CRC); however, the underlying molecular mechanisms regulating this phenomenon are poorly understood. MeCP2 is a key epigenetic regulator and is amplified in many types of cancer. Its role in CRC and the molecular mechanisms underlying its action remain unknown. Methods: We used western blot and immunohistochemistry to detect MeCP2 expression in CRC tissues, and then investigated its biological functions in vitro and in vivo. Chromatin immunoprecipitation, co-immunoprecipitation, and electrophoretic mobility shift assays were used to detect the associations among MeCP2 (Methyl-CpG binding protein 2), SPI1 (Spi-1 Proto-Oncogene), and ZEB1 (Zinc Finger E-Box Binding Homeobox 1). Results: Using the Cancer Genome Atlas and Oncomine databases, we found MeCP2 expression was upregulated in CRC tissues and this upregulation was related to poor prognosis. Meanwhile, MeCP2 depletion (KO/KD) in CRC cells significantly inhibited stem cell frequency, and invasion and migration ability in vitro, and suppressed CRC metastasis in vivo. Mechanistically, we show MeCP2 binds to the transcription factor SPI1, and aids its recruitment to the ZEB1 promoter. SPI1 then facilitates ZEB1 expression at the transcription level. In turn, ZEB1 induces the expression of MMP14, CD133, and SOX2, thereby maintaining CRC stemness and metastasis. Conclusions: MeCP2 is a novel regulator of CRC metastasis. MeCP2 suppression may be a promising therapeutic strategy in CRC.

Exosomal transfer of miR-15b-3p enhances tumorigenesis and malignant transformation through the DYNLT1/Caspase-3/Caspase-9 signaling pathway in gastric cancer

Background

Exosomes are essential for tumor growth, metastasis, and are used as novel signaling molecules in targeted therapies. Therefore, exosomal miRNAs can be used in new diagnostic and therapeutic approaches due to their involvement in the development of cancers. However, the detailed biological function, potential molecular mechanism and clinical application of exo-miR-15b-3p in gastric cancer (GC) remains unclear.

Methods

miR-15b-3p mRNA levels in tissues, serum, cells and exosomes were analyzed using qRT-PCR assays. qRT-PCR, immunohistochemical and western blotting analyses were utilized for the determination of DYNLT1 expression. The interrelationship connecting miR-15b-3p with DYNLT1 was verified using Dual-luciferase report, western blotting and qRT-PCR assays. Fluorescent PKH-26 or GFP-Lv-CD63 labeled exosomes, as well as Cy3-miR-15b-3p, were utilized to determine the efficacy of the transfer of exo-miR-15b-3p between BGC-823 and recipient cells. Several in vitro assays and xenograft tumor models were conducted to determine exo-miR-15b-3p impact on GC progression.

Results

This is the first study to confirm high miR-15b-3p expression in GC cell lines, tissues and serum. Exosomes obtained from 108 GC patient serum samples and GC cell-conditioned medium were found to show upregulation of exo-miR-15b-3p, with the area under the ROC curve (AUC) being 0.820 [0.763–0.876], which is superior to the AUC of tissues and serum miR-15b-3p (0.674 [0.600–0.748] and 0.642 [0.499–0.786], respectively). In addition, high exo-miR-15b-3p expression in serum was found to accurately predict worse overall survival. SGC-7901 and GES-1 cells are capable of internalizing BGC-823 cell-derived exosomes, allowing the transfer of miR-15b-3p. Migration, invasion, proliferation and inhibition of apoptosis in vitro and in vivo were enhanced by exo-miR-15b-3p, by restraining DYNLT1, Cleaved Caspase-9 and Caspase-3 expression.

Conclusions

This study identified a previously unknown regulatory pathway, exo-miR-15b-3p/DYNLT1/Caspase-3/Caspase-9, which promotes GC development and GES-1 cell malignant transformation. Therefore, serum exo-miR-15b-3p may be a potential GC diagnosis and prognosis biomarker, which can be used in precise targeted GC therapy.

Foxf1 knockdown promotes BMSC osteogenesis in part by activating the Wnt/β-catenin signalling pathway and prevents ovariectomy-induced bone loss

BACKGROUND

Forkhead box protein f1 (Foxf1) is associated with cell differentiation, and may be a key player in bone homoeostasis. However, the effect of Foxf1 on osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) and ovariectomy-induced bone loss, as well as its clinical implications, is unknown.

METHODS

By quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and western blotting, we assayed Foxf1 expression in bone tissue, BMSCs, and bone marrow-derived macrophages (BMMs), derived from ovariectomised (OVX) mice, and during osteogenic differentiation and osteoclast differentiation. Using a loss-of-function approach (small interfering RNA [siRNA]-mediated knockdown) in vitro, we examined whether Foxf1 regulates osteoblast differentiation of BMSCs via the Wnt/β-catenin signalling pathway. Furthermore, we assessed the anabolic effect of Foxf1 knockdown (siFoxf1) in OVX mice in vivo. We also assayed the expression of Foxf1 in bone tissue derived from postmenopausal osteoporosis (PMOP) patients and its link with bone mineral density (BMD). Finally, we examined the effect of Foxf1 knockdown on the osteoblastic differentiation of human BMSCs.

FINDINGS

Foxf1 expression was significantly increased in bone extract and BMSCs from OVX mice and gradually decreased during osteoblastic differentiation of BMSCs but did not differ significantly in OVX mouse-derived BMMs or during osteoclast differentiation. In vitro, Foxf1 knockdown markedly increased the expression of osteoblast specific genes, alkaline phosphatase (ALP) activity, and mineralisation. Moreover, siFoxf1 activated the Wnt/β-catenin signalling pathway. The siFoxf1-induced increase in osteogenic differentiation was partly rescued by inhibitor of Wnt signalling (DKK1). In OVX mice, Foxf1 siRNA significantly reduced bone loss by enhancing bone formation. Foxf1 expression levels negatively correlated with reduced bone mass and bone formation in bone tissue from PMOP patients. Finally, Foxf1 knockdown significantly promoted osteogenesis by human BMSCs.

INTERPRETATION

Our findings indicate that Foxf1 knockdown promotes BMSC osteogenesis and prevents OVX-induced bone loss. Therefore, Foxf1 has potential as a biomarker of osteogenesis and may be a therapeutic target for PMOP.

MyoD1 suppresses cell migration and invasion by inhibiting FUT4 transcription in human gastric cancer cells

Myogenic differentiation 1 (MyoD1) is a transcription factor that promotes expression of muscle-specific genes. MyoD1 is expressed at significantly lower levels in gastric cancer (GC) tissues and cells, and it induces apoptosis in GC cells. However, functions for MyoD1 in GC cell migration and gene expression have not been documented. We show that knockdown of MyoD1 promoted migration and invasion of GC cells, whereas MyoD1 overexpression suppressed migration and invasion. We performed chromatin immunoprecipitation (ChIP)-sequencing to identify MyoD1 target genes in MKN-45 cells. The 2-kb upstream regions (Up2k) of the transcription start sites of 57 genes were probably bound by MyoD1. Six of these genes function in signaling pathways such as synthesis of glycosphingolipid biosynthesis—lacto and neolacto series. MyoD1 inhibited transcription of fucosyltransferase IV (FUT4) by binding directly to the FUT4 F3; this finding was validated by ChIP-quantitative PCR and a luciferase reporter assay. Ulex europaeus agglutinin I, which binds Fucα1-2Galβ1-4GlcNAc, and Lewis antigens showed decreased binding to the plasma membrane of cells that overexpressed MyoD1. Knockdown of FUT4 mimicked MyoD1 overexpression by suppressing GC cell migration and invasion; this result implied that MyoD1 suppressed cell migration and invasion via inhibiting the FUT4/matrix metallopeptidase signaling pathway. In summary, this study demonstrated that MyoD1 suppresses migration and invasion of GC cells by directly binding to the F3 region in the FUT4 Up2k and inhibiting FUT4/type II Lewis antigen expression.

MicroRNA-1269 promotes cell proliferation via the AKT signaling pathway by targeting RASSF9 in human gastric cancer

Background

MicroRNAs (miRNAs) play key roles in tumorigenesis and progression of gastric cancer (GC). miR-1269 has been reported to be upregulated in several cancers and plays a crucial role in carcinogenesis and cancer progression. However, the biological function of miR-1269 in human GC and its mechanism remain unclear and need to be further elucidated.

Methods

The expression of miR-1269 in GC tissues and cell lines was detected by quantitative real-time PCR (qRT-PCR). Target prediction programs (TargetScanHuman 7.2 and miRBase) and a dual-luciferase reporter assay were used to confirm that Ras-association domain family 9 (RASSF9) is a target gene of miR-1269. The expression of RASSF9 was measured by qRT-PCR and Western blotting in GC tissues. MTT and cell counting assays were used to explore the effect of miR-1269 on GC cell proliferation. The cell cycle and apoptosis were measured by flow cytometry. RASSF9 knockdown and overexpression were used to further verify the function of the target gene.

Results

We found that miR-1269 expression was upregulated in human GC tissues and cell lines. The overexpression of miR-1269 promoted GC cell proliferation and cell cycle G1-S transition and suppressed apoptosis. The inhibition of miR-1269 inhibited cell growth and G1-S transition and induced apoptosis. miR-1269 expression was inversely correlated with RASSF9 expression in GC tissues. RASSF9 was verified to be a direct target of miR-1269 by using a luciferase reporter assay. The overexpression of miR-1269 decreased RASSF9 expression at both the mRNA and protein levels, and the inhibition of miR-1269 increased RASSF9 expression. Importantly, silencing RASSF9 resulted in the same biological effects in GC cells as those induced by overexpression of miR-1269. Overexpression of RASSF9 reversed the effects of miR-1269 overexpression on GC cells. Both miR-1269 overexpression and RASSF9 silencing activated the AKT signaling pathway, which modulated cell cycle regulators (Cyclin D1 and CDK2). In contrast, inhibition of miR-1269 and RASSF9 overexpression inhibited the AKT signaling pathway. Moreover, miR-1269 and RASSF9 also regulated the Bax/Bcl-2 signaling pathway.

Conclusions

Our results demonstrate that miR-1269 promotes GC cell proliferation and cell cycle G1-S transition by activating the AKT signaling pathway and inhibiting cell apoptosis via regulation of the Bax/Bcl-2 signaling pathway by targeting RASSF9. Our findings indicate an oncogenic role of miR-1269 in GC pathogenesis and the potential use of miR-1269 in GC therapy.

MicroRNA-561 Affects Proliferation and Cell Cycle Transition Through PTEN/AKT Signaling Pathway by Targeting P-REX2a in NSCLC

MicroRNAs (miRNAs) play crucial roles in tumorigenesis and tumor progression. miR-561 has been reported to be downregulated in gastric cancer and affects cancer cell proliferation and metastasis. However, the role and underlying molecular mechanism of miR-561 in human non-small cell lung cancer (NSCLC) remain unknown and need to be further elucidated. In this study, we discovered that miR-561 expression was downregulated in human NSCLC tissues and cell lines. The overexpression of miR-561 inhibited NSCLC cell proliferation and cell cycle G₁/S transition and induced apoptosis. The inhibition of miR-561 facilitated cell proliferation and G₁/S transition and suppressed apoptosis. miR-561 expression was inversely correlated with P-REX2a expression in NSCLC tissues. P-REX2a was confirmed to be a direct target of miR-561 using a luciferase reporter assay. The overexpression of miR-561 decreased P-REX2a expression, and the suppression of miR-561 increased P-REX2a expression. Particularly, P-REX2a silencing recapitulated the cellular and molecular effects observed upon miR-561 overexpression, and P-REX2a overexpression counteracted the effects of miR-561 overexpression on NSCLC cells. Moreover, both exogenous expression of miR-561 and silencing of P-REX2a resulted in suppression of the PTEN/AKT signaling pathway. Our study demonstrates that miR-561 inhibits NSCLC cell proliferation and G₁/S transition and induces apoptosis through suppression of the PTEN/AKT signaling pathway by targeting P-REX2a. These findings indicate that miR-561 plays a significant role in NSCLC progression and serves as a potential therapeutic target for NSCLC.

miR-491 inhibits BGC-823 cell migration via targeting HMGA2

PURPOSE

miR-491 functions as a tumor suppressor in several types of cancer. However, its function and mechanism in gastric cancer proliferation and metastasis have not been well defined. The aim of this study was to explore the role and regulatory mechanism of miR-491 in cell proliferation and migration in gastric cancer.

METHODS

Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to detect the expression pattern of miR-491 in gastric cancer tissues. miR-491 overexpression vector, miR-491 inhibitor, and siHMGA2 were used; and MTT, wound healing, and transwell assays were employed to examine proliferation and migration for BGC-823 cells. A dual-luciferase reporter gene was used to measure the target relationship between miR-491 and HMGA2.

RESULTS

Most gastric cancer patients exhibit decreased miR-491 expression. miR-491 overexpression inhibited cell proliferation and migration, whereas miR-491 inhibitor treatment produced the opposite effect. Mechanistically, HMGA2 was identified as a direct target of miR-491. Moreover, HMGA2 knockdown inhibited cell proliferation and migration, which was similar to the effect of miR-491 overexpression. HMGA2 was decreased after transfection of the miR-491 vector and increased after transfection of the miR-491 inhibitor.

CONCLUSION

Our results suggest that miR-491 suppressed cell proliferation and cell motility in gastric cancer by targeting HMGA2. Silencing HMGA2 produced a similar effect to miR-491 overexpression on cell proliferation and migration. miR-491/HMGA2 signaling may be a potential therapeutic target for gastric cancer patients with decreased miR-491 expression.

LDLRAD2 overexpression predicts poor prognosis and promotes metastasis by activating Wnt/β-catenin/EMT signaling cascade in gastric cancer

The therapeutic strategies for advanced gastric cancer (GC) remain unsatisfying and limited. Therefore, it is still imperative to fully elucidate the mechanisms underlying GC aggressive progression. The prognostic value and biological functions of low density lipoprotein receptor class A domain containing protein 2 (LDLRAD2) in GC have never been studied yet. We found that LDLRAD2 expression was significantly upregulated in GC and closely correlated with poor prognosis in GC patients. Functionally, LDLRAD2 promoted epithelial-mesenchymal transition, migration and invasion, and metastasis of GC cells. Mechanistically, LDLRAD2 interacted with and inhibited Axin1 from binding to cytoplasmic β-catenin, which facilitated the nuclear translocation of β-catenin, thereby activating Wnt/β-catenin pathway. Inhibition of β-catenin activity markedly abolished LDLRAD2-induced migration, invasion and metastasis. Together, these results suggested that LDLRAD2 contributed to invasion and metastasis of GC through activating Wnt/β-catenin pathway. LDLRAD2/ Wnt/β-catenin axis may be a potential therapeutic target for GC treatment.

Epigenetic regulation of IncRNA KCNKI5-ASI in gastric cancer

Background

Long noncoding RNAs (lncRNAs) play an important role in gastric cancer. In this study, we aimed to uncover the epigenetic regulatory mechanism of lncRNA KCNK15-AS1 in gastric cancer progression.

Patients and methods

Forty patients were included in the study. The expression of KCNK15-AS1 was detected by real-time PCR (RT-PCR), the promoter of KCNK15-AS1 was detected by methylation-specific PCR, and the luciferase assay was performed to detect the relationship between KCNK15-AS1 and miR-21. The relationship of the proteins was explored by an RNA pull-down assay and RNA immunoprecipitation. Chromatin immunoprecipitation was performed to detect the relationship between the promoter and the protein.

Results

The expression of KCNK15-AS1 was lower in the tumor tissue compared to the normal tissue. KCNK15-AS1 interacted with miR-21. Both the overexpression of KCNK15-AS1 and the knockdown of the expression of miR-21 inhibited proliferation and promoted apoptosis and decreased the level of MMP-9, bcl-2, and MMP-2 but increased the level of Bax. In addition, the methylation of KCNK15-AS1 was detected in the tumor tissue but was not detected in the normal tissue. Treatment with 5-azacytidine and chidamide decreased the level of DNMT1 and HDAC1 and increased the level of KCNK15-AS1. The RNA pull-down and RNA immunoprecipitation results showed that KCNK15-AS1 interacted with DNMT1 and HDAC1. The ChIP-seq result showed that the promoter of MAPK interacted with DNMT1, and the promoter of AKT and STAT5 interacted with HDAC1.

Conclusion

In this study, we identified two regulatory axes, namely KCNK15-AS1-DNMT1-MAPK and KCNK15-AS1-HDAC1-AKT, which were associated with gastric cancer progression. Chidamide and 5-azacytidine might provide new modes for treating gastric cancer.

DNA Methylation as a Future Therapeutic and Diagnostic Target in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a long-term autoimmune disease of unknown etiology that leads to progressive joint destruction and ultimately to disability. RA affects as much as 1% of the population worldwide. To date, RA is not a curable disease, and the mechanisms responsible for RA development have not yet been well understood. The development of more effective treatments and improvements in the early diagnosis of RA is direly needed to increase patients' functional capacity and their quality of life. As opposed to genetic mutation, epigenetic changes, such as DNA methylation, are reversible, making them good therapeutic candidates, modulating the immune response or aggressive synovial fibroblasts (FLS-fibroblast-like synoviocytes) activity when it is necessary. It has been suggested that DNA methylation might contribute to RA development, however, with insufficient and conflicting results. Besides, recent studies have shown that circulating cell-free methylated DNA (ccfDNA) in blood offers a very convenient, non-invasive, and repeatable "liquid biopsy", thus providing a reliable template for assessing molecular markers of various diseases, including RA. Thus, epigenetic therapies controlling autoimmunity and systemic inflammation may find wider implications for the diagnosis and management of RA. In this review, we highlight current challenges associated with the treatment of RA and other autoimmune diseases and discuss how targeting DNA methylation may improve diagnostic, prognostic, and therapeutic approaches.