N6-methyladenosine (m6A) reader IGF2BP2 promotes gastric cancer progression via targeting SIRT1

IMPlications of IMP2 in RNA Biology and Disease

Insulin-like growth factor 2 mRNA-binding protein 2 (IMP2) is an RNA-binding protein that positively regulates m6A-modified RNAs involved in critical cellular processes such as metabolism, oncogenesis, and immune function. Here, we elucidate facets of IMP2 biology, including several mechanisms of action on RNA, factors that regulate IMP2 expression, its relevant biological target RNAs, its role in normal development and disease, and its potential as a therapeutic target. IMP2 is a multi-level regulator of metabolism, influencing pathways linked to diabetes, obesity, and adipose function. Through genomic amplification and transcriptional overexpression in cancer cells, IMP2 can drive the initiation and progression of multiple cancer types, and high expression is associated with decreased overall survival of patients with cancer. IMP2 influences normal immune function, inflammation, macrophage polarization, and tumor immune evasion. IMP2 has emerged as a promising therapeutic target, particularly for cancers and metabolic diseases.

Multifaceted roles of insulin‑like growth factor 2 mRNA binding protein 2 in human cancer (Review)

Insulin‑like growth factor 2 mRNA binding protein 2 (IGF2BP2) is an RNA binding protein that functions as an N6‑methyladenosine reader. It regulates various biological processes in human cancers by affecting the stability and expression of target RNA transcripts, including coding RNAs and non‑coding RNAs (ncRNAs). Numerous studies have shown that IGF2BP2 expression is aberrantly increased in various types of cancer and plays multifaceted roles in the development and progression of human cancers. In the present review, the clinical importance of IGF2BP2 is summarized and its involvement in the regulation of biological processes, including proliferation, metastasis, chemoresistance, metabolism, tumor immunity, stemness and cell death, in human cancers is discussed. The chemical compounds that have been developed as IGF2BP2 inhibitors are also detailed. As ncRNAs are now important potential therapeutic agents for cancer treatment, the microRNAs that have been reported to directly target and inhibit IGF2BP2 expression in cancers are also described. In summary, by reviewing the latest literature, the present study aimed to highlight the clinical importance and physiological functions of IGF2BP2 in human cancer, with a focus on the great potential of IGF2BP2 as a target for inhibitor development. The present review may inspire new ideas for future studies on IGF2BP2, which may serve as a specific therapeutic target in cancer.

SLC50A1 inhibits the doxorubicin sensitivity in hepatocellular carcinoma cells through regulating the tumor glycolysis

Metabolic reprogramming has been found to be closely associated with the occurrence and development of hepatocellular carcinoma (HCC). The relationship between SLC50A1, a member of the SLC family involved in glucose transmembrane transport, and HCC remains unclear. This study aims to investigate the function and underlying mechanisms of SLC50A1 in the occurrence and progression of HCC. Based on bioinformatics analysis and clinical sample testing, we observed a significant upregulation of SLC50A1 in HCC, which is correlated with unfavorable prognosis in HCC patients. Additionally, there is a noticeable correlation between the expressions of SLC50A1 and METTL3. Further in vitro and in vivo experiments confirmed that SLC50A1 can regulate cellular glycolysis and the cell cycle, thereby promoting the proliferation of HCC cells while reducing apoptosis. Moreover, our findings indicate that SLC50A1 enhances resistance of HCC cells to DOX and 2-DG. Furthermore, we discovered that the m6A methyltransferase METTL3 mediates the methylation modification of SLC50A1. The recognition and binding of the modified SLC50A1 by IGF2BP2 subsequently promote its stability and translational expression. Consequently, our research identifies the METTL3/SLC50A1 axis as a novel therapeutic target in the context of HCC.

M2 Macrophage exosomal HOXC13-AS in laryngeal cancer immunity via targeting miR-485-5p/IGF2BP2/PD-L1

This study investigates the role of M2-exo-mediated HOXC13-AS in laryngeal squamous cell carcinoma (LSCC) by examining its transmission to tumor microenvironment (TME) macrophages. Exosomes from M2 macrophages were isolated and characterized using transmission electron microscopy, nanoparticle tracer analysis and western blot. Expression of HOXC13-AS, miR-485-5p, IGF2BP2, and PD-L1 was analyzed. Different interventions on LSCC cell function and immune escape were detected using molecular biological techniques. The study found that elevated HOXC13-AS were present in LSCC, and M2-exo expression was significantly increased in LSCC cells. Silencing HOXC13-AS in M2-exo inhibited LSCC malignant progression and immune escape in vivo and in vitro. M2-exo-mediated HOXC13-AS also regulated IGF2BP2 expression, impacting cellular biological function and immune escape process. The study concludes that M2-exo-mediated HOXC13-AS promotes LSCC malignancy and immune escape.

N6-methyladenosine modification of SLC38A7 promotes cell migration, invasion, oxidative phosphorylation, and mitochondrial function in gastric cancer

Solute carrier (SLC) 38 family, responsible for trans-membrane transport of neutral amino acids, plays a role in the proliferation, invasion, and metastasis of cancer cells, but its role in gastric cancer (GC) progression remains unclear. This study aimed to explore the biological effects of SLC38A7 and its regulatory mechanisms in GC. RNA expression data, tumor tissue specimens, and GC cell lines were used for bioinformatics and experimental analyses. Cell Counting Kit-8 assay, wound healing assay, and Transwell invasion assay were used to evaluate cell viability, migration, and invasion, respectively. Oxidative phosphorylation, mitochondrial membrane potential, and expression of the critical proteins in the mitochondrial respiratory chain were assayed using extracellular flux analysis, flow cytometry, and Western blot, respectively. RNA immunoprecipitation assay was used to explore the mechanisms of N6-methyladenosine (m6A) methylation. SLC38A7 was upregulated in GC tissue and cell lines. SLC38A7 silencing suppressed cell viability, migration, invasion, oxidative phosphorylation, and mitochondrial function in cancer cells. SLC38A7 overexpression had the opposite biological effects. Interactions between SLC38A7 and methyltransferase like 3 (METTL3) or insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) were detected. SLC38A7 mRNA stability was maintained by METTL3-IGF2BP2 axis in an m6A-dependent manner. Our results suggest that SLC38A7, stabilized by METTL3 and IGF2BP2-mediated m6A methylation, enhances cell viability, migration, invasion, oxidative phosphorylation, and mitochondrial function in GC, highlighting its role as a potential therapeutic target for GC.

Genomic analyses identify 15 susceptibility loci and reveal HDAC2, SOX2-OT, and IGF2BP2 in a naturally-occurring canine model of gastric cancer

Gastric cancer (GC) is the fifth most common human cancer worldwide, but the genetic etiology is largely unknown. We performed a Bayesian genome-wide association study and selection analyses in a naturally-occurring canine model of GC, the Belgian Tervuren and Sheepdog breeds, to elucidate underlying genetic risk factors. We identified 15 loci with over 90% predictive accuracy for the GC phenotype. Variant filtering revealed germline putative regulatory variants for the EPAS1 (HIF2A) and PTEN genes and a coding variant in CD101. Although closely related to Tervuren and Sheepdogs, Belgian Malinois rarely develop GC. Across-breed analyses uncovered protective haplotypes under selection in Malinois at SOX2-OT and IGF2BP2. Among Tervuren and Sheepdogs, HDAC2 putative regulatory variants were present at comparatively high frequency and were associated with GC. Here, we describe a complex genetic architecture governing GC in a dog model, including genes such as PDZRN3, that have not been associated with human GC.

CircRHBDD1 promotes immune escape via IGF2BP2/PD-L1 signaling and acts as a nanotherapeutic target in gastric cancer

BACKGROUND

Circular RNAs (circRNAs) have been implicated in the development and progression of gastric cancer (GC). However, it remains unclear whether dysregulated circRNA affects immune escape and the efficacy of immunotherapy in GC. Our aim is to investigate the molecular mechanism of circRNA affecting GC immunotherapy and identify effective molecular therapeutic targets.

METHODS

The differential expression profile of circRNAs was established through circRNA sequencing, comparing three paired GC tissues with their adjacent non-cancerous gastric tissues. The expression level of circRHBDD1 in GC tissues was then assessed using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The biological characteristics of circRHBDD1 were verified through a series of experiments, including agarose gel electrophoresis assays, RNase R treatment, and actinomycin D experiments. The prognostic value of circRHBDD1 in GC was evaluated by conducting both univariate and multivariate survival analyses. Furthermore, loss- and gain-of-function approaches were utilized to investigate the impact of circRHBDD1 on GC immune escape. RNA-sequencing, immunoprecipitation, flow cytometry, and methylated RNA immunoprecipitation (meRIP) analysis were performed to elucidate the underlying molecular mechanisms.

RESULTS

We discovered that circRHBDD1 exhibited remarkably high expression levels in GC tissues and cell lines. Notably, the high expression of circRHBDD1 was significantly correlated with poor overall survival and disease-free survival among GC patients. Both in vitro and in vivo experiments revealed that circRHBDD1 upregulated the expression of PD-L1 and impeded the infiltration of CD8+ T cells. Further, we found that circRHBDD1 binds to IGF2BP2, disrupting the interaction between E3 ligase TRIM25 and IGF2BP2, and ultimately inhibiting IGF2BP2 ubiquitination and degradation. Intriguingly, IGF2BP2 enhances PD-L1 mRNA stability through m6A modification. Additionally, we developed Poly (lactide-co-glycolic acid) (PLGA)-Polyethylene glycol (PEG)-based nanoparticles loaded with circRHBDD1 siRNA. In vivo experiments validated that the combination of PLGA-PEG(si-circRHBDD1) and anti-PD-1 offers a safe and efficacious nano-drug regimen for cancer immunotherapy.

CONCLUSION

Our results demonstrated that circRHBDD1 promoted GC immune escape by upregulating the expression of PD-L1 and reprogramming T cell-mediated immune response. Inhibition of circRHBDD1 expression could potentially enhance the response of GC patients to immunotherapy, thus improving treatment outcomes. Additionally, the development of a nanodrug delivery system provides a feasible approach for future clinical applications.

Targeting insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) for the treatment of cancer

Insulin-like growth factor 2 mRNA-binding proteins (IMPs, IGF2BPs) are RNA-binding proteins that regulate a variety of biological processes. In recent years, several studies have found that IGF2BPs play multiple roles in various biological processes, especially in cancer, and speculated on their mechanism of anticancer effect. In addition, targeting IGF2BPs or their downstream target gene has also received extensive attention as an effective treatment for different types of cancer. In this review, we summarized the recent progress on the role of IGF2BPs in cancers and their structural characteristics. We focused on describing the development of inhibitors targeting IGF2BPs and the prospects for further applications.

Identification of N6-Methyladenosine-Related Factors and the Prediction of the Regulatory Mechanism of Hair Follicle Development in Rex and Hycole Rabbits

Hair follicle development directly affects the development of the rabbit fur industry. The growth and development of a hair follicle is modified and regulated by many genes and mechanisms. M6A is an important RNA modification. However, there are few studies on the effects of the regulation of m6A on hair follicle growth and development. In this study, hematoxylin-eosin (HE) staining was used to explore the difference in hair follicle development between Rex rabbits and Hycole rabbits, and we performed m6A sequencing to identify the key genes with m6A modification in hair follicle growth. The results showed that the hair length, coarse hair percentage, primary hair follicle ratio, and skin thickness of Hycole rabbits were significantly higher than those of Rex rabbits. However, the proportion of secondary hair follicles in Hycole rabbits was significantly lower than that in Rex rabbits. In addition, we found five differential methylases, 20 differential genes, and 24 differential signaling pathways related to hair growth and development. The results of the Sankey diagram showed that 12 genes were related to 13 signal pathways. Finally, we found that five methylases regulated the development of hair follicles through differential genes/signal pathways. These findings laid a molecular foundation for the function of m6A modification in hair development.

IGF2BP2-meidated m6A modification of CSF2 reprograms MSC to promote gastric cancer progression

The interaction between tumor cells and stromal cells within the tumor microenvironment plays a critical role in cancer progression. Mesenchymal stem cells (MSCs) are important tumor stromal cells that exhibit pro-oncogenic activities when reprogrammed by the tumor. However, the precise mechanisms underlying MSC reprogramming in gastric cancer remain not well understood. QRT-PCR, western blot, and immunohistochemistry were used to examine gene and protein expression levels. In vitro and in vivo experiments were conducted to assess the biological functions of gastric cancer cells. RNA-sequencing, RNA immunoprecipitation (RIP), and meRIP assays were performed to investigate underlying molecular mechanisms. We found a significant increase in the expression and N6-methyladenosine (m6A) modification levels of colony-stimulating factor 2 (CSF2) in gastric cancer MSCs. CSF2 gene overexpression induced the reprogramming of normal MSCs into cancer-promoting MSCs, thereby enhancing the proliferation, migration, and drug resistance of gastric cancer cells through the secretion of various pro-inflammatory factors. Additionally, we demonstrated that the m6A reader IGF2BP2 bound to and stabilized CSF2 mRNA in gastric cancer MSCs. Notably, overexpression of IGF2BP2 mimicked the effect of CSF2 on MSCs, promoting gastric cancer progression. Finally, we unveiled that CSF2 induced the ubiquitination of Notch1 to reprogram MSCs. Our study highlights a critical role of IGF2BP2-mediated m6A modification of CSF2 in reprogramming MSCs, which presents a promising therapeutic target for gastric cancer.

Role of N6-methyladenosine RNA modification in gastric cancer

N6-methyladenosine (m6A) RNA methylation is the most prevalent internal modification of mammalian messenger RNA. The m6A modification affects multiple aspects of RNA metabolism, including processing, splicing, export, stability, and translation through the reversible regulation of methyltransferases (Writers), demethylases (Erasers), and recognition binding proteins (Readers). Accumulating evidence indicates that altered m6A levels are associated with a variety of human cancers. Recently, dysregulation of m6A methylation was shown to be involved in the occurrence and development of gastric cancer (GC) through various pathways. Thus, elucidating the relationship between m6A and the pathogenesis of GC has important clinical implications for the diagnosis, treatment, and prognosis of GC patients. In this review, we evaluate the potential role and clinical significance of m6A-related proteins which function in GC in an m6A-dependent manner. We discuss current issues regarding m6A-targeted inhibition of GC, explore new methods for GC diagnosis and prognosis, consider new targets for GC treatment, and provide a reasonable outlook for the future of GC research.

METTL3 Reduces Oxidative Stress-induced Apoptosis in Presbycusis by Regulating the N6-methyladenosine Level of SIRT1 mRNA

N6-methyl adenosine (m6A) modification is known to play a crucial role in various aging-related diseases. However, its involvement in presbycusis, a type of age-related hearing loss, is not yet clear. We examined the changes in oxidative stress levels in both plasma of presbycusis patients and mice. To determine the expression of m6A and its functional enzymes, we used liquid chromatography tandem-mass spectrometry (LC-MS/MS), enzyme-linked immunosorbent assay (ELISA), and RT-PCR to analyze the total RNA of presbycusis patients blood cells (n = 8). Additionally, we detected the expression of m6A functional enzymes in the cochlea of presbycusis mice using immunohistochemistry. We assessed the effects of m6A methyltransferase METTL3 on SIRT1 protein expression, reactive oxygen species (ROS) levels, and apoptosis in an oxidative stress model of organ of Corti 1 (OC1) cells. To observe the effect on SIRT1 protein expression, we interfered with the m6A recognition protein IGF2BP3 using siRNA. In both presbycusis patients and mice, there was an increased level of oxidative stress in plasma.There was a decrease in the expression of m6A, METTL3, and IGF2BP3 in presbycusis patients blood cells. The expression of METTL3 and IGF2BP3 was also reduced in the cochlea of presbycusis mice. In OC1 cells, METTL3 positively regulated SIRT1 protein levels, while reversely regulated the level of ROS and apoptosis. IGF2BP3 was found to be involved in the regulation of SIRT1 protein expression. In addition, METTL3 may play a protective role in oxidative stress-induced injury of OC1 cells, while both METTL3 and IGF2BP3 cooperatively regulate the level of m6A and the fate of SIRT1 mRNA in OC1 cells.

PIWI-interacting RNA-17458 is oncogenic and a potential therapeutic target in cervical cancer

Cervical cancer (CC) is one of the leading cancers among the female reproductive system. The piwi-interacting RNA (piRNA) function and biogenesis has been studied in various cancers, including CC. But the precise mechanism of piRNA in CC is still unknown. In our study, we found that piRNA-17458 was overexpressed in CC tissues and cells. piRNA-17458 mimic and inhibitor promoted and suppressed proliferation, migration and invasion ability of CC cells, respectively. We also demonstrated that piRNA-17458 mimic could contribute to tumor growth in mice xenograft models. Besides, we also found that the piRNA-17458 mimic could enhance mRNA N6-methyladenosine(m6A) levels and increase WTAP stability in CC cells, while the effects of the mimic was reversed by the WTAP knockdown. The results of dual luciferase reporter assay showed that WTAP was a direct target of piRNA-17458. Knockdown of WTAP attenuated proliferation, migration and invasion of CC cells in piRNA-17458 mimic group. Our finding not only demonstrates for the first time that piRNA-17458 is overexpressed in CC tissues and cells, but also shows that piRNA-17458 promotes tumorigenesis of CC in a WTAP-mediated m6A methylation manner.

METTL14 alleviates the development of osteoporosis in ovariectomized mice by upregulating m6A level of SIRT1 mRNA

The purpose of this study was to investigate whether METTL14 participated in ovariectomized (OVX)-induced osteoporosis (OP) in mice by regulating the m⁶A level of SIRT1 mRNA. OVX was performed on mice to induce OP, and mouse bone marrow stromal cells (BMSCs) and bone marrow mononuclear macrophages (BMMs) were isolated to induce osteoblast differentiation and osteoclast differentiation, respectively. The morphology of bone trabeculae was evaluated under a micro-CT scanner. The changes in pathology of bone tissues were observed through staining using hematoxylin-eosin. The number of osteoclasts was measured by tartrate-resistant acid phosphatase staining, and the content of serum calcium, PINP, and CTX-I was tested by enzyme-linked immunosorbent assay, accompanied by the measurement of the expression of SIRT1, METTL14, osteogenic marker genes, and osteoclast marker genes. The m⁶A modification level of SIRT1 and the binding between METTL14 and SIRT1 were verified. In OVX mice, SIRT1 and METTL14 were downregulated. Overexpression of SIRT1 or METTL14 increased the expression of osteogenic marker genes but decreased the expression of osteoclast marker genes. Additionally, METTL14 overexpression increased m⁶A level of SIRT1 mRNA. Furthermore, overexpression of METTL14 promoted osteoblast differentiation and suppressed osteoclast differentiation, which were reversed by knockdown of SIRT1. METTL14 promoted osteoblast differentiation and repressed osteoclast differentiation by m⁶A-dependent upregulation of SIRT1 mRNA, thereby alleviating OP development.

VIM‑AS1 promotes proliferation and drives enzalutamide resistance in prostate cancer via IGF2BP2‑mediated HMGCS1 mRNA stabilization

VIM‑AS1, a cancer‑specific long non‑coding RNA, has been recognized as a pivotal regulator in multiple types of cancer. However, the role of VIM‑AS1 in the proliferation and resistance to anti‑androgen therapy of LNCaP and C4‑2 prostate cancer cells remains to be determined. In the current study, gain‑and‑loss experiments were used to investigate the effects of VIM‑AS on the proliferation and anti‑androgen therapy of LNCaP and C4‑2 cells. RNA sequencing, RNA pulldown and RNA immunoprecipitation were used to elucidate the underlying mechanism of VIM‑AS1 driving prostate progression. It was demonstrated that VIM‑AS1 was upregulated in C4‑2 cells, an established castration‑resistant prostate cancer (CRPC) cell line, compared with in LNCaP cells, an established hormone‑sensitive prostate cancer cell line. The present study further demonstrated that VIM‑AS1 was positively associated with the clinical stage of prostate cancer. Functionally, overexpression of VIM‑AS1 decreased the sensitivity to enzalutamide treatment and enhanced the proliferation of LNCaP cells in vitro, whereas knockdown of VIM‑AS1 increased the sensitivity to enzalutamide treatment and reduced the proliferation of C4‑2 cells in vitro and in vivo. Mechanistically, 3‑hydroxy‑3‑methylglutaryl‑CoA synthase 1 (HMGCS1) was identified as one of the direct downstream targets of VIM‑AS1, and VIM‑AS1 promoted HMGCS1 expression by enhancing HMGCS1 mRNA stability through a VIM‑AS1/insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2)/HMGCS1 RNA‑protein complex. Rescue assays indicated that knockdown of HMGCS1 expression ameliorated the increase in proliferation and enzalutamide resistance of prostate cancer cells induced by VIM‑AS1 overexpression. Overall, the present study determined the roles and mechanism of the VIM‑AS1/IGF2BP2/HMGCS1 axis in regulating proliferation and enzalutamide sensitivity of prostate cancer cells and suggested that VIM‑AS1 may serve as a novel therapeutic target for the treatment of patients with CRPC.

RNA m6 A methylation in cancer

N⁶ -methyladenosine (m⁶ A) is one of the most abundant internal modifications in eukaryotic messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs). It is a reversible and dynamic RNA modification that has been observed in both internal coding segments and untranslated regions. Studies indicate that m⁶ A modifications play important roles in translation, RNA splicing, export, degradation and ncRNA processing control. In this review, we focus on the profiles and biological functions of RNA m⁶ A methylation on both mRNAs and ncRNAs. The dynamic modification of m⁶ A and its potential roles in cancer development are discussed. Moreover, we discuss the possibility of m⁶ A modifications serving as potential biomarkers for cancer diagnosis and targets for therapy.