PLAGL2 promotes Snail expression and gastric cancer progression via UCA1/miR-145-5p/YTHDF1 axis

N6-methyladenosine RNA modification in stomach carcinoma: Novel insights into mechanisms and implications for diagnosis and treatment

N6-methyladenosine (m6A) RNA methylation is crucially involved in the genesis and advancement of gastric cancer (GC) by controlling various pathobiological aspects including gene expression, signal transduction, metabolism, cell death, epithelial-mesenchymal transition, angiogenesis, and exosome function. Despite its importance, the exact mechanisms by which m6A modification influences GC biology remain inadequately explored. This review consolidates the latest advances in uncovering the mechanisms and diverse roles of m6A in GC and proposes new research and translational directions. Key regulators (writers, readers, and erasers) of m6A, such as METTL3/14/16 and WTAP, significantly affect cancer progression, anticancer immune response, and treatment outcomes. m6A modification also impacts immune cell infiltration and the tumor microenvironment, highlighting its potential as a diagnostic and prognostic marker. Interactions between m6A methylation and non-coding RNAs offer further novel insights into GC development and therapeutic targets. Targeting m6A regulators could enhance immunotherapy response, overcome treatment resistance, and improve oncological and clinical outcomes. Models based on m6A can precisely predict treatment response and prognosis in GC. Additional investigation is needed to fully understand the mechanisms of m6A methylation and its potential clinical applications and relevance (e.g., as precise markers for early detection, prediction of outcome, and response to therapy and as therapeutic targets) in GC. Future research should focus on in vivo studies, potential clinical trials, and the examination of m6A modification in other types of cancers.

Recent Advances in the Mutual Regulation of m6A Modification and Non-Coding RNAs in Atherosclerosis

Atherosclerosis, a progressive inflammatory disease of the arteries, remains a leading cause of cardiovascular morbidity and mortality worldwide. Recent years have witnessed the pivotal role of N6-methyladenosine (m6A) RNA methylation in regulating various biological processes, including those implicated in atherosclerosis. Current evidence suggested that m6A regulators (writers, erasers, and readers) participated in the modification of multiple non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), thereby affecting their metabolism and functions. Meanwhile, ncRNAs have also emerged as key modulator of m6A regulators expression in turn. Therefore, understanding the mutual regulation between m6A modifications and ncRNAs is of great significance to identify novel therapeutic targets for atherosclerosis and has great clinical application prospects. This review aims to summarize the recent advances in the reciprocal regulation and provide insights into the interaction between m6A modification and ncRNAs in the context of atherosclerosis.

METTL3 as a potential therapeutic target in gastric cancer

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. N6-methyladenosine (m6A) modification is the most prominent epigenetic modification of eukaryotic mRNAs, and methyltransferase-like 3 (METTL3), a core component of the methyltransferase complex, catalyzes m6A modification. The results of previous studies indicate that the expression level of METTL3 is significantly elevated in gastric cancer tissues and cells. In addition, fluctuations in m6A levels induced by METTL3 are closely associated with the malignant progression of tumors as well as the poor prognosis of patients with gastric cancer. In this review, we focus on the potential mechanism of METTL3 in gastric cancer, and through our analysis, we suggest that targeting METTL3 could be a new therapeutic tool for treating GC.

An imbalance between proliferation and differentiation underlies the development of microRNA-defective pineoblastoma

Mutations in the microRNA processing genes DICER1 and DROSHA drive several cancers that resemble embryonic progenitors. To understand how microRNAs regulate tumorigenesis, we ablated Drosha or Dicer1 in the developing pineal gland to emulate the pathogenesis of pineoblastoma, a brain tumor that resembles undifferentiated precursors of the pineal gland. Accordingly, these mice develop pineal tumors marked by loss of microRNAs, including the let-7/miR-98-5p family, and de-repression of microRNA target genes. Pineal tumors driven by loss of Drosha or Dicer1 mimic tumors driven by Rb1 loss, as they exhibit upregulation of S-phase genes and homeobox transcription factors that regulate pineal development. Blocking proliferation of these tumors facilitates expression of pinealocyte maturation markers, with a concomitant reduction in embryonic markers. Select embryonic markers remain elevated, however, as the microRNAs that normally repress these target genes remain absent. One such microRNA target gene is the oncofetal transcription factor Plagl2, which regulates expression of pro-growth genes, and inhibiting their signaling impairs tumor growth. Thus, we demonstrate that tumors driven by loss of microRNA processing may be therapeutically targeted by inhibiting downstream drivers of proliferation.

LncRNA UCA1 promotes vasculogenic mimicry by targeting miR-1-3p in gastric cancer

Long noncoding RNA urothelial carcinoma-associated 1 (UCA1) has been implicated in several tumors. UCA1 promotes cell proliferation, migration, and invasion of gastric cancer (GC) cells, but the molecular mechanism has not been fully elucidated. This study revealed the oncogenic effects of UCA1 on cell growth and invasion. Furthermore, UCA1 expression was significantly correlated with the overall survival of GC patients, and the clinicopathological indicators, including tumor size, depth of invasion, lymph node metastasis, and TNM stage. Additionally, miR-1-3p was identified as a downstream target of UCA1, which was negatively regulated by UCA1. MiR-1-3p inhibited cell proliferation and vasculogenic mimicry (VM), and induced cell apoptosis by upregulating BAX, BAD, and tumor suppressor TP53 expression levels. Moreover, miR-1-3p almost completely reversed the oncogenic effect caused by UCA1, including cell growth, migration, and VM formation. This study also confirmed that UCA1 promoted tumor growth in vivo. In this study, we also revealed the correlation between UCA1 and VM formation, which is potentially crucial for tumor metastasis. Meanwhile, its downstream target miR-1-3p inhibited VM formation in GC cells. In summary, these findings indicate that the UCA1/miR-1-3p axis is a potential target for GC treatment.

Dysregulation of autophagy in gastric carcinoma: Pathways to tumor progression and resistance to therapy

The considerable death rates and lack of symptoms in early stages of gastric cancer (GC) make it a major health problem worldwide. One of the most prominent risk factors is infection with Helicobacter pylori. Many biological processes, including those linked with cell death, are disrupted in GC. The cellular "self-digestion" mechanism necessary for regular balance maintenance, autophagy, is at the center of this disturbance. Misregulation of autophagy, however, plays a role in the development of GC. In this review, we will examine how autophagy interacts with other cell death processes, such as apoptosis and ferroptosis, and how it affects the progression of GC. In addition to wonderful its role in the epithelial-mesenchymal transition, it is engaged in GC metastasis. The role of autophagy in GC in promoting drug resistance stands out. There is growing interest in modulating autophagy for GC treatment, with research focusing on natural compounds, small-molecule inhibitors, and nanoparticles. These approaches could lead to breakthroughs in GC therapy, offering new hope in the fight against this challenging disease.

Ubiquitin-specific proteases: From biological functions to potential therapeutic applications in gastric cancer

Deubiquitination, a post-translational modification regulated by deubiquitinases, is essential for cancer initiation and progression. Ubiquitin-specific proteases (USPs) are essential elements of the deubiquitinase family, and are overexpressed in gastric cancer (GC). Through the regulation of several signaling pathways, such as Wnt/β-Catenin and nuclear factor-κB signaling, and the promotion of the expression of deubiquitination- and stabilization-associated proteins, USPs promote the proliferation, metastasis, invasion, and epithelial-mesenchymal transition of GC. In addition, the expression of USPs is closely related to clinicopathological features, patient prognosis, and chemotherapy resistance. USPs therefore could be used as prognostic biomarkers. USP targeting small molecule inhibitors have demonstrated strong anticancer activity. However, they have not yet been tested in the clinic. This article provides an overview of the latest fundamental research on USPs in GC, aiming to enhance the understanding of how USPs contribute to GC progression, and identifying possible targets for GC treatment to improve patient survival.

YTHDF1 in Tumor Cell Metabolism: An Updated Review

With the advancement of research on m6A-related mechanisms in recent years, the YTHDF protein family within m6A readers has garnered significant attention. Among them, YTHDF1 serves as a pivotal member, playing a crucial role in protein translation, tumor proliferation, metabolic reprogramming of various tumor cells, and immune evasion. In addition, YTHDF1 also exerts regulatory effects on tumors through multiple signaling pathways, and numerous studies have confirmed its ability to assist in the reprogramming of the tumor cell-related metabolic processes. The focus of research on YTHDF1 has shifted in recent years from its m6A-recognition and -modification function to the molecular mechanisms by which it regulates tumor progression, particularly by exploring the regulatory factors that interact with YTHDF1 upstream and downstream. In this review, we elucidate the latest signaling pathway mechanisms of YTHDF1 in various tumor cells, with a special emphasis on its distinctive characteristics in tumor cell metabolic reprogramming. Furthermore, we summarize the latest pathological and physiological processes involving YTHDF1 in tumor cells, and analyze potential therapeutic approaches that utilize YTHDF1. We believe that YTHDF1 represents a highly promising target for future tumor treatments and a novel tumor biomarker.

A novel long non-coding RNA XLOC_004787, is associated with migration and promotes cancer cell proliferation by downregulating mir-203a-3p in gastric cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) have been identified as important regulatory factors implicated in a wide array of diseases, including various forms of cancer. However, the roles of most lncRNAs in the progression of gastric cancer (GC) remain largely unexplored. This study investigates the biological function and underlying mechanism of a novel lncRNA, XLOC_004787 in GC.

METHODS

The location of XLOC_004787 in GES-1 cells and HGC-27 cells were detected by fluorescence in situ hybridization (FISH) assay. The expression levels of XLOC_004787 were assessed using quantitative real-time fluorescence PCR (qRT-PCR) in various cell lines, including GES-1, MGC-803, MKN-45, BGC-823, SGC-7901, and HGC-27 cells. Functional assays such as Transwell migration, cell counting kit-8 (CCK-8), and colony formation experiments were employed to analyze the effects of XLOC_004787 and miR-203a-3p on cell migration and proliferation. Protein levels associated with GC in these cell lines were examined by Western blotting. The intracellular localization of β-catenin and P-Smad2/3 was assessed using immunofluorescence (IF) assay. Additionally, the interaction between XLOC_004787 and miR-203a-3p was investigated using a dual luciferase assay.

RESULTS

XLOC_004787 was localized at both the cytoplasm and nucleus of GES-1 cells and HGC-27 cells. Compared to normal tissues and GES-1 cells, XLOC_004787 expression was significantly upregulated in GC tissues and cells, with the highest and lowest expression observed in SGC-7901 and HGC-27 cells, respectively. Furthermore, a reduced expression of XLOC_004787 was seen to inhibit migration and proliferation in SGC-7901 cells. Western blotting analysis revealed that a decrease in XLOC_004787 expression correspondingly decreased the expression of N-cadherin, mmp2, mmp9, Snail, Vimentin, β-catenin, C-myc, Cyclin D1, and TGF-β, while concurrently increasing E-cadherin expression. This was also associated with diminished expression of P-Smad2/3 in relation to Smad2/3, and reduced P-Gsk3β expression in comparison to Gsk3β. Additionally, the nuclear entry of P-Smad2/3 and β-catenin was reduced by lower XLOC_004787 expression. Amplifying XLOC_004787 expression via pcDNA_XLOC_004787 suggested a potential for cancer promotion. Notably, XLOC_004787 was found to negatively regulate mir-203a-3p expression, with potential binding sites identified between the two. Higher mir-203a-3p expression was observed to decrease migration and proliferation, and enhance E-cadherin expression. Conversely, suppression of mir-203a-3p expression suggested a potential promotion of proliferation and migration in GC cells.

CONCLUSIONS

These results suggest that XLOC_004787, found to be upregulated in GC tissues, potentially promotes proliferation and migration in GC cells. This occurs through the activation of TGF-β and Wnt/β-catenin signaling pathways and the expression of EMT-related proteins. Additionally, XLOC_004787 may influence cell migration and proliferation by modulating the signaling pathway via the adsorption and inhibition of mir-203a-3p.

PLAGL2 promotes bladder cancer progression via RACGAP1/RhoA GTPase/YAP1 signaling

PLAGL2 is upregulated in various tumors, including bladder cancer (BCa). However, the mechanisms underlying the tumorigenic effects of PLAGL2 in BCa remain unclear. In our study, we proved that PLAGL2 was overexpressed in BCa tissues and correlated with decreased survival. Functionally, PLAGL2 deficiency significantly suppressed the proliferation and metastasis of BCa cells in vitro and in vivo. RNA sequencing, qRT‒PCR, immunoblotting, immunofluorescence staining, luciferase reporter, and ChIP assays revealed that overexpressed PLAGL2 disrupted the Hippo pathway and increased YAP1/TAZ activity by transactivating RACGAP1. Further investigations demonstrated that PLAGL2 activated YAP1/TAZ signaling via RACGAP1-mediated RhoA activation. Importantly, the RhoA inhibitor simvastatin or the YAP1/TAZ inhibitor verteporfin abrogated the proproliferative and prometastatic effects of BCa enhanced by PLAGL2. These findings suggest that PLAGL2 promotes BCa progression via RACGAP1/RhoA GTPase/YAP1 signaling. Hence, the core nodes of signaling may be promising therapeutic targets for BCa.

Tumor-Associated Fibroblast-Derived Exosomal circDennd1b Promotes Pituitary Adenoma Progression by Modulating the miR-145-5p/ONECUT2 Axis and Activating the MAPK Pathway

TAF participated in the progression of various cancers, including PA via the release of soluble factors. Exosomes belonged to extracellular vesicles, which were revealed as a crucial participator in intercellular communication. However, the expression pattern and effect of TAF-derived exosomes remained largely unknown in PA. In the present study, we performed in silico analysis based on public RNA-seq datasets to generate the circRNA/miRNA regulatory network. The qRT-PCR, Western blotting, RNA pull-down, and luciferase assay were performed to investigate the effect of TAF-derived exosomes. TAF-derived exosomal circDennd1b was significantly upregulated in PA and promoted the proliferation, migration, and invasion of PA cells via sponging miR-145-5p in PA cells. In addition, miR-145-5p directly regulated One Cut homeobox 2 (ONECUT2/OC2) expression and inhibited the promoting effect of ONECUT2 on PA. We further demonstrated that ONECUT2 transcriptionally increased fibroblast growth factor receptor 3 (FGFR3) expression, which further activates the mitogen-activated protein kinases (MAPK) pathway, thus promoting PA progression. Moreover, the suppression of TAFs by ABT-263 and ONECUT2 by CSRM617 inhibited the growth of PA. In conclusion, our study illustrated that TAF-derived exosomal circDennd1b affected PA progression via regulating ONECUT2 expression, which provides a potential therapeutic strategy against aggressive PA.