LOC101929709 promotes gastric cancer progression by aiding LIN28B to stabilize c-MYC mRNA

The role of Lin28A and Lin28B in cancer beyond Let-7

Lin28A and Lin28B are paralogous RNA-binding proteins that play fundamental roles in development and cancer by regulating the microRNA family of tumor suppressor Let-7. Although Lin28A and Lin28B share some functional similarities with Let-7 inhibitors, they also have distinct expression patterns and biological functions. Increasing evidence indicates that Lin28A and Lin28B differentially impact cancer stem cell properties, epithelial-mesenchymal transition, metabolic reprogramming, and other hallmarks of cancer. Therefore, it is important to understand the overexpression of Lin28A and Lin28B paralogs in specific cancer contexts. In this review, we summarize the main similarities and differences between Lin28A and Lin28B, their implications in different cellular processes, and their role in different types of cancer. In addition, we provide evidence of other specific targets of each lin28 paralog, as well as the lncRNAs and miRNAs that promote or inhibit its expression, and how this impacts cancer development and progression.

The essential roles of lncRNAs/PI3K/AKT axis in gastrointestinal tumors

The role of long noncoding RNA (lncRNA) in tumors, particularly in gastrointestinal tumors, has gained significant attention. Accumulating evidence underscores the interaction between various lncRNAs and diverse molecular pathways involved in cancer progression. One such pivotal pathway is the PI3K/AKT pathway, which serves as a crucial intracellular mechanism maintaining the balance among various cellular physiological processes for normal cell growth and survival. Frequent dysregulation of the PI3K/AKT pathway in cancer, along with aberrant activation, plays a critical role in driving tumorigenesis. LncRNAs modulate the PI3K/AKT signaling pathway through diverse mechanisms, primarily by acting as competing endogenous RNA to regulate miRNA expression and associated genes. This interaction significantly influences fundamental biological behaviors such as cell proliferation, metastasis, and drug resistance. Abnormal expression of numerous lncRNAs in gastrointestinal tumors often correlates with clinical outcomes and pathological features in patients with cancer. Additionally, these lncRNAs influence the sensitivity of tumor cells to chemotherapy in multiple types of gastrointestinal tumors through the abnormal activation of the PI3K/AKT pathway. These findings provide valuable insights into the mechanisms underlying gastrointestinal tumors and potential therapeutic targets. However, gastrointestinal tumors remain a significant global health concern, with increasing incidence and mortality rates of gastrointestinal tumors over recent decades. This review provides a comprehensive summary of the latest research on the interactions of lncRNA and the PI3K/AKT pathway in gastrointestinal tumor development. Additionally, it focuses on the functions of lncRNAs and the PI3K/AKT pathway in carcinogenesis, exploring expression profiles, clinicopathological characteristics, interaction mechanisms with the PI3K/AKT pathway, and potential clinical applications.

Implications of c-Myc in the pathogenesis and treatment efficacy of urological cancers

Urological cancers, including prostate, bladder, and renal cancers, are significant causes of death and negatively impact the quality of life for patients. The development and progression of these cancers are linked to the dysregulation of molecular pathways. c-Myc, recognized as an oncogene, exhibits abnormal levels in various types of tumors, and current evidence supports the therapeutic targeting of c-Myc in cancer treatment. This review aims to elucidate the role of c-Myc in driving the progression of urological cancers. c-Myc functions to enhance tumorigenesis and has been documented to increase growth and metastasis in prostate, bladder, and renal cancers. Furthermore, the dysregulation of c-Myc can result in a diminished response to therapy in these cancers. Non-coding RNAs, β-catenin, and XIAP are among the regulators of c-Myc in urological cancers. Targeting and suppressing c-Myc therapeutically for the treatment of these cancers has been explored. Additionally, the expression level of c-Myc may serve as a prognostic factor in clinical settings.

RNA modifications in cellular metabolism: implications for metabolism-targeted therapy and immunotherapy

Cellular metabolism is an intricate network satisfying bioenergetic and biosynthesis requirements of cells. Relevant studies have been constantly making inroads in our understanding of pathophysiology, and inspiring development of therapeutics. As a crucial component of epigenetics at post-transcription level, RNA modification significantly determines RNA fates, further affecting various biological processes and cellular phenotypes. To be noted, immunometabolism defines the metabolic alterations occur on immune cells in different stages and immunological contexts. In this review, we characterize the distribution features, modifying mechanisms and biological functions of 8 RNA modifications, including N6-methyladenosine (m6A), N6,2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N4-acetylcytosine (ac4C), N7-methylguanosine (m7G), Pseudouridine (Ψ), adenosine-to-inosine (A-to-I) editing, which are relatively the most studied types. Then regulatory roles of these RNA modification on metabolism in diverse health and disease contexts are comprehensively described, categorized as glucose, lipid, amino acid, and mitochondrial metabolism. And we highlight the regulation of RNA modifications on immunometabolism, further influencing immune responses. Above all, we provide a thorough discussion about clinical implications of RNA modification in metabolism-targeted therapy and immunotherapy, progression of RNA modification-targeted agents, and its potential in RNA-targeted therapeutics. Eventually, we give legitimate perspectives for future researches in this field from methodological requirements, mechanistic insights, to therapeutic applications.

Long-term MNNG exposure promotes gastric carcinogenesis by activating METTL3/m6A/miR1184 axis-mediated epithelial-mesenchymal transition

As the representative item of environmental chemical carcinogen, MNNG was closely associated with the onset of Gastric cancer (GC), while the underlying mechanisms remain largely unknown. Here, we comprehensively analyzed the potential clinical significance of METTL3 in multiple GC patient cohorts. Additionally, we demonstrated that long-term exposure to MNNG elevated METTL3 and EMT marker expression by in vitro and in vivo models. Furthermore, the depletion of METTL3 impacted the proliferation, migration, invasion, and tumorigenesis of MNNG malignant transformation cells and GC cells. By me-RIP sequencing, we identified a panel of vital miRNAs potentially regulated by METTL3 that aberrantly expressed in MNNG-induced GC cells. Mechanistically, we showed that METTL3 meditated miR-1184/TRPM2 axis by regulating the process of miRNA-118. Our results provide novel insights into critical epigenetic molecular events vital to MNNG-induced gastric carcinogenesis. These findings suggest the potential therapeutic targets of METTL3 for GC treatment.

N6-methyladenosine modification of OIP5-AS1 promotes glycolysis, tumorigenesis, and metastasis of gastric cancer by inhibiting Trim21-mediated hnRNPA1 ubiquitination and degradation

BACKGROUND

Opa-interacting protein 5 antisense transcript 1 (OIP5-AS1) has been demonstrated to play vital roles in development and progression of tumors such as gastric cancer (GC). However, the detailed molecular mechanism of OIP5-AS1 has not been completely elucidated. Our study aimed to investigate the role and the epigenetic regulation mechanism of OIP5-AS1 in GC.

METHODS

OIP5-AS1 expression in GC tissues was detected by RT-qPCR. Loss- and gain-of-function experiments were conducted to assess the biological function of OIP5-AS1 in vitro and in vivo. The interaction of OIP5-AS1 with insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) or heterogeneous nuclear nucleoprotein A1 (hnRNPA1) was verified by bioinformatics analysis, RNA pull-down assays, and RNA immunoprecipitation assays.

RESULTS

In this study, we identified that OIP5-AS1 is specifically overexpressed in GC tumor tissues and cell lines and correlated with a poor prognosis. The loss of OIP5-AS1 suppressed the proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and glycolysis of GC cells, but the ectopic expression of OIP5-AS1 had the opposite impact. Meanwhile, knockdown of OIP5-AS1 inhibited tumor growth in patient-derived xenograft models, as well as repressed tumor metastasis. Mechanistically, IGF2BP3 could bind to OIP5-AS1 by N6-methyladenosine (m6A) modification sites on OIP5-AS1, thereby stabilizing OIP5-AS1. Moreover, OIP5-AS1 prevented Trim21-mediated ubiquitination and degradation of hnRNPA1, stabilizing hnRNPA1 protein and promoting the malignant progression of GC by regulating PKM2 signaling pathway.

CONCLUSIONS

In conclusion, this study highlighted that OIP5-AS1 is an oncogenic m6A-modified long non-coding RNA (lncRNA) in GC and that IGF2BP3/OIP5-AS1/hnRNPA1 axis may provide a potential diagnostic or prognostic target for GC.

LncRNA CCAT1 facilitates the progression of gastric cancer via PTBP1-mediated glycolysis enhancement

BACKGROUND

Gastric cancer (GC) is one of the most prevalent malignant tumors of the digestive system. As a hallmark of cancer, energy-related metabolic reprogramming is manipulated by multiple factors, including long non-coding RNAs (lncRNAs). Notably, lncRNA CCAT1 has been identified as a crucial regulator in tumor progression. Nevertheless, the precise molecular mechanisms underlying the involvement of CCAT1 in metabolic reprogramming of GC remain unclear.

METHODS

Gain- and loss-of-function experiments were performed to evaluate the roles of CCAT1 in tumorigenesis and glycolysis of GC. Bioinformatics analyses and mechanistic experiments, such as mass spectrometry (MS), RNA-pulldown, and RNA immunoprecipitation (RIP), were employed to reveal the potential interacting protein of CCAT1 and elucidate the regulatory mechanism of CCAT1 in GC glycolysis. Moreover, the nude mice xenograft assay was used to evaluate the effect of CCAT1 on GC cells in vivo.

RESULTS

In this study, we identified that CCAT1 expression was significantly elevated in the tissues and plasma exosomes of GC patients, as well as GC cell lines. Functional experiments showed that the knockdown of CCAT1 resulted in a substantial decrease in the proliferation, migration and invasion of GC cells both in vitro and in vivo through decreasing the expression of glycolytic enzymes and glycolytic rate. Conversely, overexpression of CCAT1 exhibited contrasting effects. Mechanistically, CCAT1 interacted with PTBP1 and effectively maintained its stability by inhibiting the ubiquitin-mediated degradation process. As a critical splicing factor, PTBP1 facilitated the transition from PKM1 to PKM2, thereby augmenting the glycolytic activity of GC cells and ultimately fostering the progression of GC.

CONCLUSIONS

Our findings demonstrate that CCAT1 plays a significant role in promoting the proliferation, migration, and invasion of GC cells through the PTBP1/PKM2/glycolysis pathway, thus suggesting CCAT1's potential as a biomarker and therapeutic target for GC.

m6A-regulated tumor glycolysis: new advances in epigenetics and metabolism

Glycolytic reprogramming is one of the most important features of cancer and plays an integral role in the progression of cancer. In cancer cells, changes in glucose metabolism meet the needs of self-proliferation, angiogenesis and lymphangiogenesis, metastasis, and also affect the immune escape, prognosis evaluation and therapeutic effect of cancer. The n6-methyladenosine (m6A) modification of RNA is widespread in eukaryotic cells. Dynamic and reversible m6A modifications are widely involved in the regulation of cancer stem cell renewal and differentiation, tumor therapy resistance, tumor microenvironment, tumor immune escape, and tumor metabolism. Lately, more and more evidences show that m6A modification can affect the glycolysis process of tumors in a variety of ways to regulate the biological behavior of tumors. In this review, we discussed the role of glycolysis in tumor genesis and development, and elaborated in detail the profound impact of m6A modification on different tumor by regulating glycolysis. We believe that m6A modified glycolysis has great significance and potential for tumor treatment.