The Roles of Insulin-Like Growth Factor 2 mRNA-Binding Protein 2 in Cancer and Cancer Stem Cells

The regulatory roles of RNA-binding proteins in the tumour immune microenvironment of gastrointestinal malignancies

The crosstalk between the tumour immune microenvironment (TIME) and tumour cells promote immune evasion and resistance to immunotherapy in gastrointestinal (GI) tumours. Post-transcriptional regulation of genes is pivotal to GI tumours progression, and RNA-binding proteins (RBPs) serve as key regulators via their RNA-binding domains. RBPs may exhibit either anti-tumour or pro-tumour functions by influencing the TIME through the modulation of mRNAs and non-coding RNAs expression, as well as post-transcriptional modifications, primarily N6-methyladenosine (m6A). Aberrant regulation of RBPs, such as HuR and YBX1, typically enhances tumour immune escape and impacts prognosis of GI tumour patients. Further, while targeting RBPs offers a promising strategy for improving immunotherapy in GI cancers, the mechanisms by which RBPs regulate the TIME in these tumours remain poorly understood, and the therapeutic application is still in its early stages. This review summarizes current advances in exploring the roles of RBPs in regulating genes expression and their effect on the TIME of GI tumours, then providing theoretical insights for RBP-targeted cancer therapies.

CircATP5C1 promotes triple-negative breast cancer progression by binding IGF2BP2 to modulate CSF-1 secretion

Triple-negative breast cancer (TNBC) is a common malignant disease among females and severely threatens the health of women worldwide. Nowadays, circular RNAs (circRNAs) aroused our interest for their functions in human cancers, including TNBC. However, the mechanism of most circRNAs in the progression of TNBC remains unclear. We found a novel circRNA named circATP5C1, whose function in TNBC remains uncovered. Tissue microarray was used to analyze the association between the expression of circATP5C1 and the prognoses of TNBC patients. Gain-and loss-of-function experiments were performed to validate the biological functions of circATP5C1 in different TNBC cell lines. RNA-seq analyses were conducted to find out the target genes regulated by circATP5C1. RNA pull-down assay and mass spectrometry were used to select the proteins associated with circATP5C1. RNA FISH-immunofluorescence and RNA immunoprecipitation (RIP) were complemented to validate the interaction between circATP5C1 and its binding protein. CircATP5C1 was identified to have predictive function in prognosis of TNBC patients. CircATP5C1 advanced the progression of TNBC cells. Mechanistically, Colony stimulating factor 1 (CSF-1) is a vital downstream gene regulated by circATP5C1. The alteration of CSF-1 expression level was validated due to the interaction between circATP5C1 and insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2). Rescue experiments demonstrated that circATP5C1 accelerates the progression of TNBC partly via binding with IGF2BP2 to increase the secretion of CSF-1. This study uncovers a novel mechanism of circATP5C1/IGF2BP2/CSF-1 pathway in regulating progression of TNBC.

A pan-cancer analysis reveals the oncogenic and immunological role of insulin-like growth factor 2 mRNA-binding protein family members

PURPOSE

To investigate the expression and clinical significance of insulin-like growth factor 2 mRNA-binding protein family members (IGF2BPs) in pan-cancer and evaluate their potential as targets for tumor immunotherapy.

METHODS

Based on data from the cancer genome atlas (TCGA) database, pan-cancer analysis was conducted to examine the clinical significance of IGF2BPs expression in twenty-two tumors.

RESULTS

Differential expression analysis showed high expression of IGF2BPs in most tumor tissues. Survival and mutation analyses suggested that the overexpression of IGF2BPs was associated with poor prognosis and mutation status of certain tumors. Methylation analysis revealed the methylation levels of IGF2BP1/2/3 in certain tumors were intricately linked to their mRNA expression, patient prognosis, and immune cell infiltration. Enrichment analysis indicated that abnormal expression of IGF2BPs was associated with various common tumor-related pathways in different tumors, including AMPK, Hippo, PI3K-Akt, EMT, and p53. In addition, immune correlation analysis revealed that IGF2BPs were closely related to immunotherapy-related indicators (immune cell infiltration, major histocompatibility complex (MHC), immune checkpoints, tumor mutation burden (TMB), and microsatellite instability (MSI)) in some tumors. Drug sensitivity analysis indicated that IGF2BPs were sensitive to some common chemotherapeutic drugs (alvocidib, dasatinib, trametinib, and selumetinib).

CONCLUSION

IGF2BPs exhibit significantly high expression in most tumors and are associated with prognosis, pathological stage, mutational status, methylation levels, and the relevant indicators of immunotherapy sensitivity in multiple tumors. Moreover, IGF2BPs may play an oncogenic role by activating common signaling pathways. Therefore, IGF2BPs may be potential prognostic markers for tumor therapy and targets for immunotherapy and drug therapy.

Inhibition of METTL3 Attenuates Renal Fibrosis by Upregulating ABCG2 m6A Modifications via IGF2BP2-Dependent Mechanisms in Hyperuricemic Nephropathy

Hyperuricemia has been linked to kidney problems including hyperuricemic nephropathy (HN), which is characterised by inflammation and fibrosis in the kidneys. HN is frequently observed in patients with chronic gout. However, the causes of HN are not fully understood and effective treatments are limited. The status of RNA m6A, expression, and location of METTL3 in the kidney was evaluated in mice with HN. The mechanism of the METTL3-associated ABCG2 downregulation was further studied in mTEC cells and a potassium oxazinate + adenine-induced mice model and adeno-associated virus 9 (AAV9)-mediated METTL3 silencing mice. Expressions of ABCG2, α-SMA, collagen-1, TGF-β1, IL-1β, IL-6, and TNF-α were analysed using real-time PCR and western blotting. Hyperuricemia led to elevated m6A levels and METTL3 expression in mouse kidneys. METTL3 was mainly located in mTEC cells. METTL3-specific inhibitor STM2457 alleviated uric acid-induced inflammatory and fibrotic responses in mTEC cells. Mechanistically, ABCG2 was identified as a target of METTL3 by RNA sequencing. The stability of ABCG2 was decreased through the binding of IGF2BP2 (insulin-like growth factor 2 binding protein 2) to its m6A-modified stop codon regions. Silencing or inhibition of METTL3 significantly reduced uric acid-induced cell injury and increased ABCG2 expression, leading to uric acid excretion. In vivo data showed that AAV9-mediated METTL3 silencing significantly alleviated renal dysfunction and fibrosis in HN mice. Our study provides the first evidence that METTL3 regulates uric acid excretion by controlling the m6A levels of ABCG2 through the binding of IGF2BP2, and inhibiting METTL3 can effectively alleviate kidney damage caused by hyperuricemia, showing potential as a therapy for HN.

The sterol-regulating human ARV1 binds cholesterol and phospholipids through its conserved ARV1 homology domain

Evidence suggests that ARV1 regulates sterol movement within the cell. Saccharomyces cerevisiae cells lacking ScArv1 have defects in sterol trafficking, distribution, and biosynthesis. HepG2 cells treated with hARV1 antisense oligonucleotides accumulate cholesterol in the endoplasmic reticulum. Mice lacking Arv1 have a lean phenotype when fed a high fat diet and show no signs of liver triglyceride or cholesterol accumulation, suggesting a role for Arv1 in lipid transport. Here, we explored the direct lipid-binding activity of recombinant human ARV1 using in vitro lipid-binding assays. ARV1 lipid-binding activity was observed within the first N-terminal 98 amino acids containing the conserved ARV1 homology domain (AHD). The zinc-binding domain and conserved cysteine clusters within the AHD were necessary for lipid binding. Both full-length ARV1 and the AHD bound cholesterol, several phospholipids, and phosphoinositides with high affinity. The AHD showed the highest binding affinity for monophosphorylated phosphoinositides. Several conserved amino acids within the AHD were necessary for phospholipid binding. Biochemical studies suggested that ARV1 exists as a dimer in cells, with oligomerization being critical for ARV1 function, as amino acid mutations predicted to have a negative effect on dimerization caused weakened or complete loss of lipid binding. Our results show for the first time that human ARV1 can directly bind cholesterol and phospholipids. How this activity may function to regulate lipid binding and maintain proper lipid trafficking and/or transport in cells requires further studies.

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.

IGF2BP2-induced circRNF20 facilitates breast cancer cell proliferation via the HuR/CDCA4 axis

This study aimed to explore the mechanism of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) affecting the proliferation of breast cancer (BC) cells. The expression of IGF2BP2, circRNA ring finger protein 20 (circRNF20), and cell division cycle-associated protein 4 (CDCA4) in human BC cells and normal breast epithelial cells was detected via RT-qPCR or Western blotting. After IGF2BP2 expression was altered, CCK-8 assay, colony formation assay, and EdU staining were performed to evaluate changes in the proliferation of BC cells. RNA immunoprecipitation (RIP) assay was used to analyze the binding of circRNF20 to IGF2BP2 or HuR, as well as the binding of HuR to CDCA4. RNA pull-down confirmed the interaction between circRNF20 and HuR. The stability of circRNF20 was tested after treatment with actinomycin D. A nude mouse xenograft tumor model was established to validate the effect of IGF2BP2 in vivo. IGF2BP2, circRNF20, and CDCA4 were highly expressed in BC cells. Silencing IGF2BP2 decreased the proliferation ability of BC cells. Mechanistically, the binding of IGF2BP2 to circRNF20 prevented circRNF20 degradation, thereby promoting the binding of circRNF20 to HuR and increasing the expression of CDCA4. The overexpression of circRNF20 or CDCA4 abolished the inhibitory effect of IGF2BP2 silencing on BC cell proliferation. In conclusion, the binding of IGF2BP2 to circRNF20 prevents its degradation, thus facilitating BC cell proliferation via the HuR/CDCA4 axis.

Knockdown of IGF2BP2 overcomes cisplatin-resistance in lung cancer through downregulating Spon2 gene

BACKGROUND

Cisplatin (DDP) resistance has long posed a challenge in the clinical treatment of lung cancer (LC). Insulin-like growth factor 2 binding protein 2 (IGF2BP2) has been identified as an oncogenic factor in LC, whereas its specific role in DDP resistance in LC remains unclear.

RESULTS

In this study, we investigated the role of IGF2BP2 on DDP resistance in DDP-resistant A549 cells (A549/DDP) in vitro and in a DDP-resistant lung tumor-bearing mouse model in vivo. Additionally, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was conducted to identify the potential mRNAs regulated by IGF2BP2, an N6-methyladenosine (m6A) regulator, in the tumor tissues of mice. Compared to normal tissues, IGF2BP2 levels were increased in LC tissues and in relapsed/resistant LC tissues. Most importantly, IGF2BP2 levels were significantly higher in relapsed/resistant LC tissues than in LC tissues. Significantly, knockdown of IGF2BP2 or DDP treatment inhibited A549 cell viability, migration, and cell cycle progression. Consistently, DDP treatment suppressed the viability and migration and triggered cell cycle arrest in A549/DDP cells in vitro, as well as reduced tumor volume and weight of A549/DDP tumor-bearing mice; meanwhile, the combination of DDP and IGF2BP2 siRNA further significantly inhibited A549/DDP cell growth in vitro and in vivo compared to DDP treatment alone. Furthermore, MeRIP-seq data showed that IGF2BP2 downregulation remarkably elevated m6A levels of spondin 2 (Spon2) and reduced mRNA levels of Spon2 in tumor tissues from A549 tumor-bearing mice. Meanwhile, the combination of DDP and IGF2BP2 siRNA notably reduced Spon2 levels, as well as inhibited the viability and induced apoptosis in A549/DDP cells; however, these effects were reversed by Spon2 overexpression.

CONCLUSION

Collectively, downregulation of IGF2BP2 could overcome DDP resistance in LC through declining the Spon2 gene expression in an m6A-dependent manner. These results may provide a new strategy for overcoming DDP resistance in LC.

IGF2BP2 Shapes the Tumor Microenvironment by Regulating Monocyte and Macrophage Recruitment in Bladder Cancer

BACKGROUND

Immunotherapy has shown promise for bladder cancer (BC) treatment but is effective only in a subset of patients. Understanding the tumor microenvironment (TME) and its regulators, such as the expression of N6-methyladenosine (m6A) regulators, may improve therapeutic outcomes. This study focuses on the role of IGF2BP2, an m6A reader, in modulating the BC TME.

METHODS

Transcriptomic and single-cell RNA-seq data from public databases were analyzed to identify BC subgroups and investigate IGF2BP2's role in the TME. Clustering and PCA identified key m6A regulators. NicheNet and SCENIC analyses were used to predict cell-cell interactions and transcriptional regulators, respectively. IGF2BP2's role in macrophage recruitment was validated via co-culture experiments and RNA sequencing.

RESULTS

Unsupervised clustering identified BC subgroups with distinct TME characteristics, with IGF2BP2 emerging as a key regulator associated with poor prognosis and reduced response to immunotherapy. Single-cell analysis revealed IGF2BP2's high expression in the GE-9 epithelial subpopulation, characterized by immune evasion features and cytokine-mediated macrophage recruitment. NicheNet analysis showed that GE-9 cells interact with monocyte/macrophage populations through cytokine signaling. Co-culture experiments confirmed IGF2BP2's role in recruiting macrophages, partially mediated by CCL2. Furthermore, IGF2BP2 expression was linked to immunosuppressive M2-like and SPP1+ macrophages, contributing to an angiogenesis-promoting and immunosuppressive TME.

CONCLUSION

IGF2BP2 shapes the BC TME by modulating macrophage infiltration and polarization, leading to an immunosuppressive microenvironment that hinders immunotherapy. Targeting IGF2BP2 could enhance the efficacy of current therapies and improve patient outcomes.

Association between genetic polymorphisms and gestational diabetes mellitus susceptibility in a Chinese population

Background

Although the association between HHEX, IGF2BP2, and FTO polymorphisms and the risk of GDM has been investigated in several studies, the findings have been inconsistent across different populations. The study aimed to investigate the association between genetic polymorphisms and GDM risk in a Chinese population.

Methods

502 control volunteers and 500 GDM patients were enrolled. IGF2BP2 rs11705701 and rs4402960, FTO rs9939609, and HHEX rs1111875 and rs5015480 were all genotyped using the SNPscan™ genotyping assay. The independent sample t-test, logistic regression, and chi-square test were used to assess the variations in genotype and allele and their relationships with the risk of GDM. The blood glucose level, gestational week of delivery, and newborn weight were compared using a one-way ANOVA.

Results

After adjusting for confounding factors, the results show that the rs1111875 heterozygous (OR=1.370; 95% CI: 1.040-1.805; P = 0.025) and overdominant (OR=1.373; 95% CI: 1.049-1.796; P = 0. 021) models are significantly associated with an increased risk of GDM, especially for the age ≥ 30 years group: heterozygote (OR=1.646; 95% CI: 1.118-2.423; P=0.012) and overdominant (OR=1.553; 95% CI: 1.064-2.266; P = 0.022) models. In the age ≥ 30 years, the rs5015480 overdominant model (OR=1.595; 95% CI: 1.034-2.459; P = 0.035) and the rs9939609 heterozygote model (OR=1.609; 95% CI: 1.016-2.550; P=0.043), allele (OR=1. 504; 95% CI: 1.006-2.248; P = 0.047), dominant model (OR=1.604; 95% CI: 1.026-2.505; P = 0.038), and overdominant model (OR=1.593; 95% CI: 1.007-2.520; P = 0.047) were associated with a significantly increased risk of GDM; Additionally, people with the TC genotype of rs1111875 had a substantially higher 1-hour blood glucose level than TT genotype (P < 0.05). The results of the meta-analysis showed that the A allele of rs11705701 was associated with an increased risk of diabetes mellitus (P < 0.05).

Conclusion

The study indicates that the TC genotype of rs1111875 is linked to a higher risk of GDM, particularly in women aged 30 years or older. Additionally, rs5015480 and rs9939609 were significantly associated with GDM in the same age group. These SNPs may therefore be more closely linked to GDM in older mothers.

Deciphering the IGF2BP3-mediated control of ferroptosis: mechanistic insights and therapeutic prospects

The rapid expansion of the oncology field has revealed new insights into cell death processes, with a particular emphasis on the role of ferroptosis. Characterized by iron dependency and the accumulation of lipid peroxides and iron within cells, ferroptosis stands out as a unique form of programmed cell demise. This in-depth analysis delves into the pivotal role of IGF2BP3, an RNA-binding protein, in the complex regulatory network of ferroptosis in cancerous cells. By exerting post-transcriptional control over genes associated with iron equilibrium, IGF2BP3 is demonstrated to manage cellular iron concentrations and reactive oxygen species (ROS) equilibrium, thus affecting the destiny of the cell. The correlation between aberrant IGF2BP3 expression and increased aggressiveness, metastatic capacity, and poor prognosis in various cancers is further clarified. The potential of IGF2BP3 as a biomarker for prognosis and a therapeutic agent to enhance cancer cells' vulnerability to ferroptosis is also examined, heralding new strategies in cancer treatment.

FTO/IGF2BP2-mediated N6 methyladenosine modification in invasion and metastasis of thyroid carcinoma via CDH12

Epigenetic reprogramming plays a critical role in cancer progression of cancer, and N6-methyladenosine (m6A) is the most common RNA modification in eukaryotes. The purpose of this study was to explore the related modification mode of m6A regulator construction and evaluate the invasion and migration of thyroid cancer. Our results showed that m6A levels were significantly increased in papillary thyroid cancer (PTC) and anaplastic thyroid cancer (ATC) samples, which may have been induced by the down-regulation of demethylase fat mass and obesity-associated gene (FTO). Moreover, FTO inhibited PTC and ATC invasion and metastasis through the epithelial-to-mesenchymal transition (EMT) pathway in vivo and in vitro. Mechanistically, an m6A-mRNA epitranscriptomic microarray showed that Cadherin 12 (CDH12) is the key target gene mediated by FTO in an m6A-dependent manner. CDH12 promotes invasion and metastasis through the EMT pathway in thyroid cancer, both in vivo and in vitro. Furthermore, we found that insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) is an important m6A reading protein, that regulates the stability of CDH12 mRNA and mediates EMT progression, thereby promoting the invasion and metastasis of PTC and ATC. Thus, FTO, IGF2BP2 and CDH12 may be effective therapeutic targets for PTC and ATC with significant invasion or distant metastasis. Schematic summary of FTO-IGF2BP2 axis in modulation of CDH12 mRNA m6A and upregulation of CDH12 expression in the invasion and metastasis of thyroid carcinoma.

Insulin-like growth factor-2 mRNA-binding protein 2 facilitates post-ischemic angiogenesis by increasing the stability of fibroblast growth factor 2 mRNA and its protein expression

Background

Post-ischemic angiogenesis is crucial for reestablishing blood flow in conditions such as peripheral artery disease (PAD). The role of insulin-like growth factor-2 mRNA-binding protein 2 (IGF2BP2) in post-transcriptional RNA metabolism and its involvement in post-ischemic angiogenesis remains unclear.

Methods

Using a human GEO database and a hind-limb ischemia (HLI) mouse model, the predominant isoform IGF2BP2 in ischemic gastrocnemius tissue was identified. Adeno-associated virus with the Tie1 promoter induced IGF2BP2 overexpression in the HLI model, evaluating the expression of vascular structural proteins (CD31 and α-SMA) and blood flow recovery after HLI. In vitro experiments with human umbilical vein endothelial cells (HUVECs) demonstrated that lentivirus-mediated IGF2BP2 overexpression upregulates cell proliferation, migration, and tube formation. GeneCards, RNAct databases, and subsequent reverse transcription quantitative polymerase chain reaction (RT-qPCR) predicted IGF2BP2 interactions with fibroblast growth factor 2 (FGF2) mRNA, and actinomycin D treatment, binding site predictions and CLIP-seq data further confirmed this interaction. Furthermore, western blotting, enzyme-linked immunosorbent assay, and RNA immunoprecipitation followed by RT-qPCR were performed to validate IGF2BP2's interaction with FGF2 mRNA and to assess its role in stabilizing FGF2 mRNA, as well as its impact on FGF2 protein expression.

Results

HLI reduced IGF2BP2 expression in the gastrocnemius tissue, which gradually increased during blood flow recovery. IGF2BP2 overexpression in HLI mice accelerated blood flow recovery and increased capillary and small artery densities. The overexpression of IGF2BP2 in HUVECs stimulated proliferation, migration, and tube formation by interacting with FGF2 mRNA to increase its stability. This interaction resulted in increased levels of FGF2 protein and secretion, ultimately promoting angiogenesis.

Conclusions

IGF2BP2 contributes to blood flow restoration post-ischemia in vivo and promotes angiogenesis in HUVECs by enhancing FGF2 mRNA stability and FGF2 protein expression and secretion. These findings underscore IGF2BP2's therapeutic potential in ischemic conditions, such as PAD.

IGF2BP3 promotes mRNA degradation through internal m7G modification

Recent studies have suggested that mRNA internal m7G and its writer protein METTL1 are closely related to cell metabolism and cancer regulation. Here, we identify that IGF2BP family proteins IGF2BP1-3 can preferentially bind internal mRNA m7G. Such interactions, especially IGF2BP3 with m7G, could promote the degradation of m7G target transcripts in cancer cells. IGF2BP3 is more responsive to changes of m7G modification, while IGF2BP1 prefers m6A to stabilize the bound transcripts. We also demonstrate that p53 transcript, TP53, is m7G-modified at its 3'UTR in cancer cells. In glioblastoma, the methylation level and the half lifetime of the modified transcript could be modulated by tuning IGF2BP3, or by site-specific targeting of m7G through a dCas13b-guided system, resulting in modulation of cancer progression and chemosensitivity.

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.

circHIPK3 nucleates IGF2BP2 and functions as a competing endogenous RNA

Circular RNAs represent a class of endogenous RNAs that regulate gene expression and influence cell biological decisions with implications for the pathogenesis of several diseases. Here, we disclose a novel gene-regulatory role of circHIPK3 by combining analyses of large genomics datasets and mechanistic cell biological follow-up experiments. Using time-course depletion of circHIPK3 and specific candidate RNA-binding proteins, we identify several perturbed genes by RNA sequencing analyses. Expression-coupled motif analyses identify an 11-mer motif within circHIPK3, which also becomes enriched in genes that are downregulated upon circHIPK3 depletion. By mining eCLIP datasets and combined with RNA immunoprecipitation assays, we demonstrate that the 11-mer motif constitutes a strong binding site for IGF2BP2 in bladder cancer cell lines. Our results suggest that circHIPK3 can sequester IGF2BP2 as a competing endogenous RNA (ceRNA), leading to target mRNA stabilization. As an example of a circHIPK3-regulated gene, we focus on the STAT3 mRNA as a specific substrate of IGF2BP2 and validate that manipulation of circHIPK3 regulates IGF2BP2-STAT3 mRNA binding and, thereby, STAT3 mRNA levels. Surprisingly, absolute copy number quantifications demonstrate that IGF2BP2 outnumbers circHIPK3 by orders of magnitude, which is inconsistent with a simple 1:1 ceRNA hypothesis. Instead, we show that circHIPK3 can nucleate multiple copies of IGF2BP2, potentially via phase separation, to produce IGF2BP2 condensates. Our results support a model where a few cellular circHIPK3 molecules can induce IGF2BP2 condensation, thereby regulating key factors for cell proliferation.

Emerging Targets and Therapeutics in Immuno-Oncology: Insights from Landscape Analysis

In the ever-evolving landscape of cancer research, immuno-oncology stands as a beacon of hope, offering novel avenues for treatment. This study capitalizes on the vast repository of immuno-oncology-related scientific documents within the CAS Content Collection, totaling over 350,000, encompassing journals and patents. Through a pioneering approach melding natural language processing with the CAS indexing system, we unveil over 300 emerging concepts, depicted in a comprehensive "Trend Landscape Map". These concepts, spanning therapeutic targets, biomarkers, and types of cancers among others, are hierarchically organized into eight major categories. Delving deeper, our analysis furnishes detailed quantitative metrics showcasing growth trends over the past three years. Our findings not only provide valuable insights for guiding future research endeavors but also underscore the merit of tapping the vast and unparalleled breadth of existing scientific information to derive profound insights.

circHIPK3 nucleates IGF2BP2 and functions as a competing endogenous RNA

Circular RNAs (circRNAs) represent a class of widespread endogenous RNAs that regulate gene expression and thereby influence cell biological decisions with implications for the pathogenesis of several diseases. Here, we disclose a novel gene-regulatory role of circHIPK3 by combining analyses of large genomics datasets and mechanistic cell biological follow-up experiments. Specifically, we use temporal depletion of circHIPK3 or specific RNA binding proteins (RBPs) and identify several perturbed genes by RNA sequencing analyses. Using expression-coupled motif analyses of mRNA expression data from various knockdown experiments, we identify an 11-mer motif within circHIPK3, which is also enriched in genes that become downregulated upon circHIPK3 depletion. By mining eCLIP datasets, we find that the 11-mer motif constitutes a strong binding site for IGF2BP2 and validate this circHIPK3-IGF2BP2 interaction experimentally using RNA-immunoprecipitation and competition assays in bladder cancer cell lines. Our results suggest that circHIPK3 and IGF2BP2 mRNA targets compete for binding. Since the identified 11-mer motif found in circHIPK3 is enriched in upregulated genes following IGF2BP2 knockdown, and since IGF2BP2 depletion conversely globally antagonizes the effect of circHIPK3 knockdown on target genes, our results suggest that circHIPK3 can sequester IGF2BP2 as a competing endogenous RNA (ceRNA), leading to target mRNA stabilization. As an example of a circHIPK3-regulated gene, we focus on the STAT3 mRNA as a specific substrate of IGF2BP2 and validate that manipulation of circHIPK3 regulates IGF2BP2- STAT3 mRNA binding and thereby STAT3 mRNA levels. However, absolute copy number quantifications demonstrate that IGF2BP2 outnumbers circHIPK3 by orders of magnitude, which is inconsistent with a simple 1:1 ceRNA hypothesis. Instead, we show that circHIPK3 can nucleate multiple copies of IGF2BP2, potentially via phase separation, to produce IGF2BP2 condensates. Finally, we show that circHIPK3 expression correlates with overall survival of patients with bladder cancer. Our results are consistent with a model where relatively few cellular circHIPK3 molecules function as inducers of IGF2BP2 condensation thereby regulating STAT3 and other key factors for cell proliferation and potentially cancer progression.

Ubiquitin ligase TRIM15 promotes the progression of pancreatic cancer via the upregulation of the IGF2BP2-TLR4 axis

BACKGROUND

The tripartite motif family, predominantly characterized by its E3 ubiquitin ligase activities, is involved in various cellular processes including signal transduction, apoptosis and autophagy, protein quality control, immune regulation, and carcinogenesis. Tripartite Motif Containing 15 (TRIM15) plays an important role in melanoma progression through extracellular signal-regulated kinase activation; however, data on its role in pancreatic tumors remain lacking. We previously demonstrated that TRIM15 targeted lipid synthesis and metabolism in pancreatic cancer; however, other specific regulatory mechanisms remain elusive.

METHODS

We used transcriptomics and proteomics, conducted a series of phenotypic experiments, and used a mouse orthotopic transplantation model to study the specific mechanism of TRIM15 in pancreatic cancer in vitro and in vivo.

RESULTS

TRIM15 overexpression promoted the progression of pancreatic cancer by upregulating the toll-like receptor 4. The TRIM15 binding protein, IGF2BP2, could combine with TLR4 to inhibit its mRNA degradation. Furthermore, the ubiquitin level of IGF2BP2 was positively correlated with TRIM15.

CONCLUSIONS

TRIM15 could ubiquitinate IGF2BP2 to enhance the function of phase separation and the maintenance of mRNA stability of TLR4. TRIM15 is a potential therapeutic target against pancreatic cancer.

Artificial selection footprints in indigenous and commercial chicken genomes

BACKGROUND

Although many studies have been done to reveal artificial selection signatures in commercial and indigenous chickens, a limited number of genes have been linked to specific traits. To identify more trait-related artificial selection signatures and genes, we re-sequenced a total of 85 individuals of five indigenous chicken breeds with distinct traits from Yunnan Province, China.

RESULTS

We found 30 million non-redundant single nucleotide variants and small indels (< 50 bp) in the indigenous chickens, of which 10 million were not seen in 60 broilers, 56 layers and 35 red jungle fowls (RJFs) that we compared with. The variants in each breed are enriched in non-coding regions, while those in coding regions are largely tolerant, suggesting that most variants might affect cis-regulatory sequences. Based on 27 million bi-allelic single nucleotide polymorphisms identified in the chickens, we found numerous selective sweeps and affected genes in each indigenous chicken breed and substantially larger numbers of selective sweeps and affected genes in the broilers and layers than previously reported using a rigorous statistical model. Consistent with the locations of the variants, the vast majority (~ 98.3%) of the identified selective sweeps overlap known quantitative trait loci (QTLs). Meanwhile, 74.2% known QTLs overlap our identified selective sweeps. We confirmed most of previously identified trait-related genes and identified many novel ones, some of which might be related to body size and high egg production traits. Using RT-qPCR, we validated differential expression of eight genes (GHR, GHRHR, IGF2BP1, OVALX, ELF2, MGARP, NOCT, SLC25A15) that might be related to body size and high egg production traits in relevant tissues of relevant breeds.

CONCLUSION

We identify 30 million single nucleotide variants and small indels in the five indigenous chicken breeds, 10 million of which are novel. We predict substantially more selective sweeps and affected genes than previously reported in both indigenous and commercial breeds. These variants and affected genes are good candidates for further experimental investigations of genotype-phenotype relationships and practical applications in chicken breeding programs.

Whole-genome resequencing of Chinese indigenous sheep provides insight into the genetic basis underlying climate adaptation

BACKGROUND

Chinese indigenous sheep are valuable resources with unique features and characteristics. They are distributed across regions with different climates in mainland China; however, few reports have analyzed the environmental adaptability of sheep based on their genome. We examined the variants and signatures of selection involved in adaptation to extreme humidity, altitude, and temperature conditions in 173 sheep genomes from 41 phenotypically and geographically representative Chinese indigenous sheep breeds to characterize the genetic basis underlying environmental adaptation in these populations.

RESULTS

Based on the analysis of population structure, we inferred that Chinese indigenous sheep are divided into four groups: Kazakh (KAZ), Mongolian (MON), Tibetan (TIB), and Yunnan (YUN). We also detected a set of candidate genes that are relevant to adaptation to extreme environmental conditions, such as drought-prone regions (TBXT, TG, and HOXA1), high-altitude regions (DYSF, EPAS1, JAZF1, PDGFD, and NF1) and warm-temperature regions (TSHR, ABCD4, and TEX11). Among all these candidate genes, eight ABCD4, CNTN4, DOCK10, LOC105608545, LOC121816479, SEM3A, SVIL, and TSHR overlap between extreme environmental conditions. The TSHR gene shows a strong signature for positive selection in the warm-temperature group and harbors a single nucleotide polymorphism (SNP) missense mutation located between positions 90,600,001 and 90,650,001 on chromosome 7, which leads to a change in the protein structure of TSHR and influences its stability.

CONCLUSIONS

Analysis of the signatures of selection uncovered genes that are likely related to environmental adaptation and a SNP missense mutation in the TSHR gene that affects the protein structure and stability. It also provides information on the evolution of the phylogeographic structure of Chinese indigenous sheep populations. These results provide important genetic resources for future breeding studies and new perspectives on how animals can adapt to climate change.

The relationship between polymorphism of IGF2BP2 gene rs4402960 and risk of pan-cancer: a meta-analysis and a bioinformatics analysis

OBJECTIVE

To conduct a meta-analysis and a bioinformatics analysis to assess the relationship between IGF2BP2 gene polymorphism and pan-cancer risk.

METHODS

PubMed, EMBASE, and Web of Science were conducted to literature searches. The heterogeneity test was used in five genetic models. Odds ratios (OR), 95% confidence intervals (CI), and p-values were used to evaluate the combined effects of various genetic models. Subgroup analysis and Meta-regression analysis were used to analyze the characteristics of heterogeneity. Sensitivity analysis and publication bias were also performed. Transcriptomic information on IGF2BP2 was downloaded and analyzed from the TCGA and GTEx databases. GEPIA (http://gepia.cancer-pku.cn/) was performed to analyze the relationship between IGF2BP2 expression and cancer tissue.

RESULTS

This meta-analysis contained 7 case-control studies, with 5,908 cases and 7,890 controls. There were significant differences in the heterozygous genetic model of IGF2BP2 gene rs4402960 polymorphism (OR = 1.080, 95% CI = 1.003-1.163, p = 0.041). In subgroup analysis based on ethnicity, There was a statistical significant association in Chinese (heterozygous: OR = 1.110, 95% CI = 1.010-1.220, p = 0.030). Bioinformatics analysis found that IGF2BP2 was over-expressed in pan-cancer (p < 0.01). In addition, the Kaplan-Meier estimate showed that there is statistical significance of OS between the low and high IGF2BP2 TPM groups in Lung adenocarcinoma (p <0.001).

CONCLUSIONS

To sum up, IGF2BP2 gene polymorphism may be related to cancer risk. IGF2BP2 has diagnostic value in the diagnosis and treatment of pan-cancer.

Lin28 affects the proliferation and osteogenic differentiation of human dental pulp stem cells by directly inhibiting let-7b maturation

OBJECTIVE

Activation of Lin28 gene under certain conditions promotes tissue damage repair. However, it remains unknown whether conditional expression of Lin28 facilitates the recovery of damaged pulp tissue. In the study, we focus on exploring the effects and possible regulatory mechanisms of Lin28 on the proliferation and differentiation of human dental pulp stem cells (hDPSCs).

MATERIALS AND METHODS

We adopted techniques such as the ethynyl-2'-deoxyuridine (EdU) incorporation assay, RNA-protein immunoprecipitation (RIP) analysis, and luciferase assays to study the regulation of hDPSCs by Lin28. Furthermore, gain-of-function and loss-of-function analyses were also used in explored factors regulating hDPSCs activation.

RESULTS

The results show that Lin28 inhibited osteogenic differentiation by directly targets pre-let-7b. Through bioinformatics sequencing and dual luciferase experiments we learned that let-7b directly targets the IGF2BP2 3'UTR. Silencing of IGF2BP2 showed a similar biological effect as overexpression of let-7b. Overexpression of IGF2BP2 counteracted the differentiation-promoting effects produced by let-7b overexpression.

DISCUSSION/CONCLUSIONS

In conclusion, the RNA-binding protein Lin28 regulates osteogenic differentiation of hDPSCs by inhibiting let-7 miRNA maturation. And mature let-7b directly regulated the expression of IGF2BP2 by targeting the 3'UTR region of IGF2BP2 mRNA thus further inhibiting the differentiation of hDPSCs.

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.

LncRNA AGAP2-AS1 interacts with IGF2BP2 to promote bladder cancer progression via regulating LRG1 mRNA stability

BACKGROUND

The long non-coding RNA (lncRNA) AGAP2-AS1 was implicated in tumorigenesis, yet with unclear mechanism in the development of Bladder Cancer (BCa).

METHODS

We collected the clinicopathological features and tissue samples of 45 patients with BCa in Xiangya Hospital. Expressions of AGAP2-AS1 and LRG1 were detected by RT-qPCR in BCa tissues and normal tissues as well as in BCa cells. The roles of AGAP2-AS1 and LRG1 were investigated by CCK-8, colony formation assay, transwell assays and tube formation assay. The subcellular localization of AGAP2-AS1 was detected by Fluorescence in situ hybridization. Bioinformatics method, RNA immunoprecipitation, RNA pull-down assay and Actinomycin D test were used to predict and identify the relationships between AGAP2-AS1, LRG1 and IGF2BP2. Xenografted tumors were produced to explore the function of AGAP2-AS1 in BCa in vivo.

RESULTS

AGAP2-AS1 and LRG1 were highly upregulated in BCa. AGAP2-AS1 positively correlated with T stage, grade and vascular invasion, but negatively correlated with the survival of patients. Overexpressions of AGAP2-AS1 promoted proliferation, migration, invasion, tumor angiogenesis in vitro and tumor growth, metastasis in vivo, knockdown of AGAP2-AS1 exhibited the opposite effects. AGAP2-AS1 localized mainly in the cytoplasm. AGAP2-AS1 directly bound to IGF2BP2 protein to enhance LRG1 mRNA stability. Inhibition of BCa progression by AGAP2-AS1 knockdown may be reversed by LRG1 overexpression.

CONCLUSION

AGAP2-AS1 can promote BCa progression and metastasis by recruiting IGF2BP2 to stabilize LRG1.

HOXD-AS2-STAT3 feedback loop attenuates sensitivity to temozolomide in glioblastoma

AIMS

Glioblastoma multiforme (GBM) is the deadliest glioma and its resistance to temozolomide (TMZ) remains intractable. Long non-coding RNAs (lncRNAs) play crucial roles in that and this study aimed to investigate underlying mechanism of HOXD-AS2-affected temozolomide sensitivity in glioblastoma.

METHODS

We analyzed and validated the aberrant HOXD-AS2 expression in glioma specimens. Then we explored the function of HOXD-AS2 in vivo and in vitro and a clinical case was also reviewed to examine our findings. We further performed mechanistic experiments to investigate the mechanism of HOXD-AS2 in regulating TMZ sensitivity.

RESULTS

Elevated HOXD-AS2 expression promoted progression and negatively correlated with prognosis of glioma; HOXD-AS2 attenuated temozolomide sensitivity in vitro and in vivo; The clinical case also showed that lower HOXD-AS2 sensitized glioblastoma to temozolomide; STAT3-induced HOXD-AS2 could interact with IGF2BP2 protein to form a complex and sequentially upregulate STAT3 signaling, thus forming a positive feedback loop regulating TMZ sensitivity in glioblastoma.

CONCLUSION

Our study elucidated the crucial role of the HOXD-AS2-STAT3 positive feedback loop in regulating TMZ sensitivity, suggesting that this could be provided as a potential therapeutic candidate of glioblastoma.

METTL3/IGF2BP2 axis affects the progression of colorectal cancer by regulating m6A modification of STAG3

Colorectal cancer (CRC) is among the commonest malignant tumors of humans. Existing evidence has linked the poor prognosis of CRC with high expression of stromal antigen 3 (STAG3), but, the exact biological effect of STAG3 in CRC is still unclear. The aim of this research is to reveal the biological function and molecular mechanism of STAG3 in CRC. To investigate the differential expression of STAG3 in CRC tissues and cell lines compared to normal colon tissues and cell lines, Western blot (WB) and quantitative real-time PCR (qRT-PCR) techniques were utilized. STAG3 N6-methyladenosine (m6A) modification level were identified using m6A RNA immunoprecipitation (MeRIP). Additionally, the functional roles of methyltransferase-like protein 3 (METTL3) and insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) in CRC were explored by manipulating their levels via knockdown or overexpression. Cell proliferation was evaluated through Cell Counting Kit 8 (CCK-8) and clone formation experiments, while cell migration was assessed through wound healing experiments. Furthermore, cell apoptosis was detected using flow cytometry, and the protein expressions associated with proliferation and apoptosis were detected using WB. To identify the specific binding of target genes, RIP and pull-down assays were employed. Finally, the biological function of STAG3 in vivo was investigated through a xenotransplantation mouse tumor model. In CRC tissues and cell lines, STAG3 was up-regulated and accompanied by m6A methylation. Additionally, the expression of METTL3 was found to be upregulated in CRC tissues. Knocking down METTL3 resulted in a decrease in both the m6A level and protein expression of STAG3, inhibited cell proliferation and migration while promoting apoptosis, which were restored through STAG3 overexpression. Furthermore, online prediction indicated the interaction between STAG3 mRNA and IGF2BP2 protein, which was further verified by RIP experiments. IGF2BP2 downregulation led to decreased STAG3 protein expression, cell proliferation, and migration, but increased apoptosis. However, these impacts were reversed by STAG3 overexpression. Finally, subcutaneous tumor experiments conducted in nude mice also confirmed that METTL3 regulated CRC progression through STAG3 in vivo. The METTL3/IGF2BP2/STAG3 axis affects CRC progression in an m6A modification-dependent manner. This may guide targeted therapy in CRC patients.

Association Between Polymorphism in Diabetes Susceptibility Gene Insulin-Like Growth Factor 2mRNA-Binding Protein 2 and Risk of Diffuse Large B-Cell Lymphoma

Background

Numerous studies have shown that polymorphisms in the diabetes susceptibility gene, insulin-like growth factor 2mRNA-binding protein 2 (IGF2BP2), are associated with the occurrence and development of various malignant tumors; however, their correlation with the onset of diffuse large B-cell lymphoma (DLBCL) is still unknown. Therefore, this study aimed to explore whether IGF2BP2 polymorphisms increase the risk of developing DLBCL.

Methods

This study included 295 DLBCL patients and 331 healthy individuals. Peripheral blood was collected, and polymerase chain reaction-ligase detection reaction (PCR-LDR) was used to detect IGF2BP2 gene polymorphisms. Logistic regression was used to assess the association between IGF2BP2 polymorphism and the risk of DLBCL, adjusted for age, sex, and body mass index (BMI). P < .05 indicated statistical significance.

Results

The rs4402960 polymorphism in the IGF2BP2 gene was associated with the occurrence and development of DLBCL. After adjusting for age, sex, and BMI, GT (odd ratio [OR] = 1.54; 95% confidence interval [CI] = 1.08-2.19; P = .016), TT (OR = 2.00; 95% CI = 1.09-3.68; P = .026), and T genotype carrying (GT + TT) (OR = 1.62; 95% CI = 1.17-2.25; P = .004) significantly increased the risk of DLBCL. This study also found that the polymorphism rs1470579 was related to the development of DLBCL. After adjusting for age, sex, and BMI, AC (OR = 1.55; 95% CI = 1.11-2.17; P = .010), CC (OR = 2.18; 95% CI = 1.17-4.06; P = .014), and C genotype carrying (AC + CC) (OR = 1.64; 95% CI = 1.19-2.26; P = .002) significantly increased the risk of DLBCL.

Conclusions

Our study found that polymorphism in the IGF2BP2 gene was associated with an increased risk of developing DLBCL.

IGF2BP3 promotes the progression of colorectal cancer and mediates cetuximab resistance by stabilizing EGFR mRNA in an m6A-dependent manner

Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), an RNA-binding protein, is associated with tumorigenesis and progression. However, the exact molecular mechanisms of IGF2BP3 in colorectal cancer (CRC) oncogenesis, progression, and drug resistance remain unclear. This study found that IGF2BP3 was upregulated in CRC tissues. Clinically, the elevated IGF2BP3 level is predictive of a poor prognosis. Functionally, IGF2BP3 enhances CRC tumorigenesis and progression both in vitro and in vivo. Mechanistically, IGF2BP3 promotes epidermal growth factor receptor (EGFR) mRNA stability and translation and further activates the EGFR pathway by serving as a reader in an N6-methyladenosine (m6A)-dependent manner by cooperating with METTL14. Furthermore, IGF2BP3 increases the drug resistance of CRC cells to the EGFR-targeted antibody cetuximab. Taken together, our results demonstrated that IGF2BP3 was a functional and clinical oncogene of CRC. Targeting IGF2BP3 and m6A modification may therefore offer rational therapeutic targets for patients with CRC.

Comprehensive analysis of FOXM1 immune infiltrates, m6a, glycolysis and ceRNA network in human hepatocellular carcinoma

Background

Forkhead box M1 (FOXM1) is a member of the Forkhead box (Fox) transcription factor family. It regulates cell mitosis, cell proliferation, and genome stability. However, the relationship between the expression of FOXM1 and the levels of m6a modification, immune infiltration, glycolysis, and ketone body metabolism in HCC has yet to be fully elucidated.

Methods

Transcriptome and somatic mutation profiles of HCC were downloaded from the TCGA database. Somatic mutations were analyzed by maftools R package and visualized in oncoplots. GO, KEGG and GSEA function enrichment was performed on FOXM1 co-expression using R. We used Cox regression and machine learning algorithms (CIBERSORT, LASSO, random forest, and SVM-RFE) to study the prognostic value of FOXM1 and immune infiltrating characteristic immune cells in HCC. The relationship between FOXM1 and m6A modification, glycolysis, and ketone body metabolism were analyzed by RNA-seq and CHIP-seq. The competing endogenous RNA (ceRNA) network construction relies on the multiMiR R package, ENCORI, and miRNET platforms.

Results

FOXM1 is highly expressed in HCC and is associated with a poorer prognosis. At the same time, the expression level of FOXM1 is significantly related to the T, N, and stage. Subsequently, based on the machine learning strategies, we found that the infiltration level of T follicular helper cells (Tfh) was a risk factor affecting the prognosis of HCC patients. The high infiltration of Tfh was significantly related to the poor overall survival rate of HCC. Besides, the CHIP-seq demonstrated that FOXM1 regulates m6a modification by binding to the promoter of IGF2BP3 and affects the glycolytic process by initiating the transcription of HK2 and PKM in HCC. A ceRNA network was successfully obtained, including FOXM1 - has-miR-125-5p - DANCR/MIR4435-2HG ceRNA network related to the prognosis of HCC.

Conclusion

Our study implicates that the aberrant infiltration of Tfh associated with FOXM1 is a crucial prognostic factor for HCC patients. FOXM1 regulates genes related to m6a modification and glycolysis at the transcriptional level. Furthermore, the specific ceRNA network can be used as a potential therapeutic target for HCC.

IGF2BP2 promotes colorectal cancer progression by upregulating the expression of TFRC and enhancing iron metabolism

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignant tumors of the digestive system, ranking third for morbidity and mortality worldwide. At present, no effective control method is available for this cancer type. In tumor cells, especially iron metabolization, is necessary for its growth and proliferation. High levels of iron are an important feature to maintain tumor growth; however, the overall mechanism remains unclear.

METHODS

We used western blotting, immunohistochemistry (IHC) and real-time quantitative PCR to analyze the expression of IGF2BP2 in cell lines and tissues. Further, RNA-sequencing, RNA immunoprecipitation and methylated RNA immunoprecipitation experiments explored the specific binding of target genes. Moreover, the RNA stability assay was performed to determine the half-life of genes downstream of IGF2BP2. In addition, the Cell Counting Kit-8, colony formation assay, 5-ethynyl-2'-deoxyuridine assay and flow cytometry were used to evaluate the effects of IGF2BP2 on proliferation and iron metabolism. Lastly, the role of IGF2BP2 in promoting CRC growth was demonstrated in animal models.

RESULTS

We observed that IGF2BP2 is associated with iron homeostasis and that TFRC is a downstream target of IGF2BP2. Further, overexpression of TFRC can rescue the growth of IGF2BP2-knockdown CRC cells. Mechanistically, we determined that IGF2BP2 regulates TFRC methylation via METTL4, thereby regulating iron metabolism and promoting CRC growth. Furthermore, using animal models, we observed that IGF2BP2 promotes CRC growth.

CONCLUSION

IGF2BP2 regulates TFRC mRNA methylation via METTL4, thereby regulating iron metabolism and promoting CRC growth. Our study highlights the key roles of IGF2BP2 in CRC carcinogenesis and the iron transport pathways.

The Emerging Role of m6A Modification in Endocrine Cancer

With the development of RNA modification research, N6-methyladenosine (m6A) is regarded as one of the most important internal epigenetic modifications of eukaryotic mRNA. It is also regulated by methylase, demethylase, and protein preferentially recognizing the m6A modification. This dynamic and reversible post-transcriptional RNA alteration has steadily become the focus of cancer research. It can increase tumor stem cell self-renewal and cell proliferation. The m6A-modified genes may be the primary focus for cancer breakthroughs. Although some endocrine cancers are rare, they may have a high mortality rate. As a result, it is critical to recognize the significance of endocrine cancers and identify new therapeutic targets that will aid in improving disease treatment and prognosis. We summarized the latest experimental progress in the m6A modification in endocrine cancers and proposed the m6A alteration as a potential diagnostic marker for endocrine malignancies.

Insulin-like growth factor 2 mRNA-binding protein 3 promotes kidney injury by regulating β-catenin signaling

Wnt/β-catenin is a developmental signaling pathway that plays a crucial role in driving kidney fibrosis after injury. Activation of β-catenin is presumed to be regulated through the posttranslational protein modification. Little is known about whether β-catenin is also subjected to regulation at the posttranscriptional mRNA level. Here, we report that insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) plays a pivotal role in regulating β-catenin. IGF2BP3 was upregulated in renal tubular epithelium of various animal models and patients with chronic kidney disease. IGF2BP3 not only was a direct downstream target of Wnt/β-catenin but also was obligatory for transducing Wnt signal. In vitro, overexpression of IGF2BP3 in kidney tubular cells induced fibrotic responses, whereas knockdown of endogenous IGF2BP3 prevented the expression of injury and fibrosis markers in tubular cells after Wnt3a stimulation. In vivo, exogenous IGF2BP3 promoted β-catenin activation and aggravated kidney fibrosis, while knockdown of IGF2BP3 ameliorated renal fibrotic lesions after obstructive injury. RNA immunoprecipitation and mRNA stability assays revealed that IGF2BP3 directly bound to β-catenin mRNA and stabilized it against degradation. Furthermore, knockdown of IGF2BP3 in tubular cells accelerated β-catenin mRNA degradation in vitro. These studies demonstrate that IGF2BP3 promotes β-catenin signaling and drives kidney fibrosis, which may be mediated through stabilizing β-catenin mRNA. Our findings uncover a previously underappreciated dimension of the complex regulation of Wnt/β-catenin signaling and suggest a potential target for therapeutic intervention of fibrotic kidney diseases.

Human T2D-Associated Gene IMP2/IGF2BP2 Promotes the Commitment of Mesenchymal Stem Cells Into Adipogenic Lineage

Excessive adiposity is the main cause of obesity and type two diabetes (T2D). Variants in human IMP2/IGF2BP2 gene are associated with increased risk of T2D. However, little is known about its role in adipogenesis and in insulin resistance. Here, we investigate the function of IMP2 during adipocyte development. Mice with Imp2 deletion in mesenchymal stem cells (MSC) are resistant to diet-induced obesity without glucose and insulin tolerance affected. Imp2 is essential for the early commitment of adipocyte-derived stem cells (ADSC) into preadipocytes, but the deletion of Imp2 in MSC is not required for the proliferation and terminal differentiation of committed preadipocytes. Mechanistically, Imp2 binds Wnt receptor Fzd8 mRNA and promotes its degradation by recruiting CCR4-NOT deadenylase complex in an mTOR-dependent manner. Our data demonstrate that Imp2 is required for maintaining white adipose tissue homeostasis through controlling mRNA stability in ADSC. However, the contribution of IMP2 to insulin resistance, a main risk of T2D, is not evident.

miR-96-5p regulates cervical cancer cell resistance to cisplatin by inhibiting lncRNA TRIM52-AS1 and promoting IGF2BP2

MicroRNA (miRNA) and long noncoding RNA (lncRNA) are both regulators of cancer progression. This study sought to discuss the functional mechanism of miR-96-5p/lncRNA TRIM52 antisense RNA 1 (head-to-head; TRIM52-AS1) in cervical cancer (CC) cell resistance to cisplatin (DDP). DDP-resistant CC cell line was established using increasing concentrations of DDP, followed by transfection with miR-96-5p inhibitor, or si-TRIM52-AS1, or insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) overexpression vector. Expression levels of miR-96-5p, TRIM52-AS1, and IGF2BP2 were determined. Changes in IC50 value to DDP, cell proliferation, and apoptosis rate were evaluated by cell-counting kit-8 assay, colony formation, and flow cytometry. The bindings of miR-96-5p to IGF2BP2 and TRIM52-AS1 to IGF2BP2 were verified by dual-luciferase or RNA pull-down assays. These experiments revealed an up-expression of miR-96-5p and IGF2BP2 while an under-expression of TRIM52-AS1 in CC cells. After DDP treatment, miR-96-5p inhibition increased apoptosis and decreased proliferation and DDP resistance. miR-96-5p bound to TRIM52-AS1 and downregulated TRIM52-AS1 expression, and TRIM52-AS1 bound to IGF2BP2 to inhibit IGF2BP2 expression. TRIM52-AS1 inhibition or IGF2BP2 overexpression neutralized the inhibition of silencing miR-96-5p on CC cell resistance to DDP. Overall, miR-96-5p improved CC cell resistance to DDP by inhibiting TRIM52-AS1 and promoting IGF2BP2.

IGF2BP2 promotes cancer progression by degrading the RNA transcript encoding a v-ATPase subunit

IGF2BP2 binds to a number of RNA transcripts and has been suggested to function as a tumor promoter, although little is known regarding the mechanisms that regulate its roles in RNA metabolism. Here we demonstrate that IGF2BP2 binds to the 3' untranslated region of the transcript encoding ATP6V1A, a catalytic subunit of the vacuolar ATPase (v-ATPase), and serves as a substrate for the NAD⁺-dependent deacetylase SIRT1, which regulates how IGF2BP2 affects the stability of the ATP6V1A transcript. When sufficient levels of SIRT1 are expressed, it catalyzes the deacetylation of IGF2BP2, which can bind to the ATP6V1A transcript but does not mediate its degradation. However, when SIRT1 expression is low, the acetylated form of IGF2BP2 accumulates, and upon binding to the ATP6V1A transcript recruits the XRN2 nuclease, which catalyzes transcript degradation. Thus, the stability of the ATP6V1A transcript is significantly compromised in breast cancer cells when SIRT1 expression is low or knocked-down. This leads to a reduction in the expression of functional v-ATPase complexes in cancer cells and to an impairment in their lysosomal activity, resulting in the production of a cellular secretome consisting of increased numbers of exosomes enriched in ubiquitinated protein cargo and soluble hydrolases, including cathepsins, that together combine to promote tumor cell survival and invasiveness. These findings describe a previously unrecognized role for IGF2BP2 in mediating the degradation of a messenger RNA transcript essential for lysosomal function and highlight how its sirtuin-regulated acetylation state can have significant biological and disease consequences.

Liver-specific lncRNA FAM99A may be a tumor suppressor and promising prognostic biomarker in hepatocellular carcinoma

Background

Increasing evidence shows that liver-specific long non-coding RNAs (lncRNAs) play important roles in the development of hepatocellular carcinoma (HCC). We identified a novel liver-specific lncRNA, FAM99A, and examined its clinical significance and biological functions in HCC.

Methods

The expression level and clinical value of FAM99A in HCC were examined using The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and Gene Expression Omnibus (GEO) databases, and were further verified using quantitative real-time polymerase chain reaction (qRT–PCR) in our HCC cohort. Univariate and multivariate Cox proportional hazards regression models were also applied to identify independent prognostic indicators for HCC patients. Cell counting kit-8, colony formation, and Transwell assays were performed to evaluate the effects of FAM99A on the proliferation, migration, and invasion abilities of HCC cells in vitro. A subcutaneous xenograft tumor model was implemented to determine the effect of FAM99A on the tumor growth of HCC cells in vivo. RNA pull-down and mass spectrometry assays were performed to reveal the potential molecular mechanisms of FAM99A in HCC.

Results

The three public online databases and qRT–PCR data showed that FAM99A was frequently downregulated in HCC tissues and inversely correlated with microvascular invasion and advanced histological grade of HCC patients. Kaplan–Meier survival analysis indicated that decreased FAM99A was significantly associated with poor overall survival of HCC patients based on TCGA database (P = 0.040), ICGC data portal (P < 0.001), and our HCC cohort (P = 0.010). A multivariate Cox proportional hazards regression model based on our HCC cohort suggested that FAM99A was an independent prognostic factor of overall survival for HCC patients (hazard ratio: 0.425, P = 0.039). Upregulation of FAM99A suppressed the proliferation, colony formation, migration, and invasion capacities of HCC cells in vitro, and knockdown of FAM99A had the opposite effects. A subcutaneous xenograft tumor model demonstrated that overexpression of FAM99A significantly inhibited the tumor growth of HCC cells in vivo. Seven tumor-related proteins (PCBP1, SRSF5, SRSF6, YBX1, IGF2BP2, HNRNPK, and HNRNPL) were recognized as possible FAM99A-binding proteins by the RNA pull-down and mass spectrometry assays.

Conclusion

Our results suggest that FAM99A exerts cancer-inhibiting effects on HCC progression, and it may be a promising prognostic indicator for HCC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10186-2.

LCAT1 is an oncogenic LncRNA by stabilizing the IGF2BP2-CDC6 axis

Long non-coding RNAs (lncRNAs) is known to play vital roles in modulating tumorigenesis. We previously reported that LCAT1, a novel lncRNA, promotes the growth and metastasis of lung cancer cells both in vitro and in vivo. However, the underlying mechanism(s) of LCAT1 as an oncogenic regulator remains elusive. Here, we showed that LCAT1 physically interacts with and stabilizes IGF2BP2, an m⁶A reader protein, by preventing its degradation via autolysosomes. IGF2BP2 is overexpressed in lung cancer tissues, which is associated with poor survival of non-small cell lung cancer patients, suggesting its oncogenic role. Biologically, IGF2BP2 depletion inhibits growth and survival as well as the migration of lung cancer cells. Mechanistically, the LCAT1/IGF2BP2 complex increased the levels of CDC6, a key cell cycle regulator, by stabilizing its mRNA in an m⁶A-dependent manner. Like IGF2BP2, CDC6 is also overexpressed in lung cancer tissues with poor patient survival, and CDC6 knockdown has oncogenic inhibitory activity. Taken together, the LCAT1-IGF2BP2-CDC6 axis appears to play a vital role in promoting the growth and migration of lung cancer cells, and is a potential therapeutic target for lung cancer. Importantly, our finding also highlights a previously unknown critical role of LCAT1 in m⁶A-dependent gene regulation by preventing autolytic degradation of IGF2BP2.

The Insulin-like Growth Factor System and Colorectal Cancer

Insulin-like growth factors (IGFs) are peptides which exert mitogenic, endocrine and cytokine activities. Together with their receptors, binding proteins and associated molecules, they participate in numerous pathophysiological processes, including cancer development. Colorectal cancer (CRC) is a disease with high incidence and mortality rates worldwide, whose etiology usually represents a combination of the environmental and genetic factors. IGFs are most often increased in CRC, enabling excessive autocrine/paracrine stimulation of the cell growth. Overexpression or increased activation/accessibility of IGF receptors is a coinciding step which transmits IGF-related signals. A number of molecules and biochemical mechanisms exert modulatory effects shaping the final outcome of the IGF-stimulated processes, frequently leading to neoplastic transformation in the case of irreparable disbalance. The IGF system and related molecules and pathways which participate in the development of CRC are the focus of this review.

Long noncoding RNA LIPH-4 promotes esophageal squamous cell carcinoma progression by regulating the miR-216b/IGF2BP2 axis

Introduction

Esophageal squamous cell carcinoma (ESCC) represents a major malignancy with poor clinical outcomes. Long noncoding RNAs (lncRNAs) are known to regulate the development and progression of multiple cancers. However, how lncRNAs are involved in ESCC is currently undefined.

Methods

LIPH-4 levels in ESCC tissue specimens and cells were assessed by qRT-PCR. The biological function of LIPH-4 was examined in cell and animal studies, applying CCK-8, EdU, colony formation and flow cytometry assays as well as xenograft model experiments. The underlying mechanisms of action of LIPH-4 were explored through bioinformatics, luciferase reporter assay, RNA-immunoprecipitation assay and immunoblot.

Results

We identified a novel lncRNA, LIPH-4, which showed elevated amounts in ESCC tissues and positive correlations with increased tumor size and poor prognosis in ESCC patients. Functional studies showed that LIPH-4 promoted the growth, mediated cell cycle progression and inhibited apoptosis in ESCC cells in vitro, and promoted tumor growth in mice. In terms of mechanism, LIPH-4 could bind to miR-216b and act as a competing endogenous RNA (ceRNA) to induce the expression of miR-216’s target gene IGF2BP2. LIPH-4 played an oncogenic role in ESCC through the miR-216b/IGF2BP2 axis.

Conclusions

This study suggested that LIPH-4 functions as a novel oncogenic lncRNA by acting as a ceRNA for miR-216b to regulate IGF2BP2, indicating LIPH-4 likely constitutes a prognostic biomarker and therapeutic target in ESCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-022-00408-x.

Circular RNA circPBX3 promotes cisplatin resistance of ovarian cancer cells via interacting with IGF2BP2 to stabilize ATP7A mRNA expression

Circular RNAs (circRNAs) are a class of non-coding RNAs with a unique covalently closed loop structure. Recent studies indicate that dysregulation of circRNAs acts a role in cancer progression and chemotherapy resistance via interacting with RNA-binding proteins (RBPs). Herein, we identified circPBX3 to be involved in cisplatin resistance of ovarian cancer. In our study, two cisplatin-resistant ovarian cancer cell lines were established, and transcriptome RNA-sequencing was performed and circPBX3 was identified as significantly upregulated circRNA in these cells. The characteristics of circPBX3 and potential function of circPBX3 were evaluated. We found that circPBX3 was upregulated in ovarian tumor tissues and cisplatin-resistant ovarian cancer cells. CircPBX3 overexpression increased the half maximal inhibitory rate (IC₅₀) of cisplatin, promoted colony formation and tumor xenografts growth, and reduced cell apoptosis of ovarian cancer cells under cisplatin treatment, while silencing circPBX3 showed opposite effects. Furthermore, circPBX3 could interact with the RNA-binding protein IGF2BP2, thus increased the stability of ATP7A mRNA and elevated ATP7A protein level. In addition, silencing ATP7A in ovarian cancer cells abrogated the effect of circPBX3 overexpression on cisplatin tolerance. Our findings provided a novel role of circPBX3 in cisplatin resistance of ovarian cancer.

Circular RNA circ-TNPO3 inhibits clear cell renal cell carcinoma metastasis by binding to IGF2BP2 and destabilizing SERPINH1 mRNA

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is a common malignant tumour of the urinary tract. The major causes of poor prognosis are the lack of early diagnosis and metastasis. Accumulating research reveals that circular RNAs (circRNAs) can play key roles in the development and the progression of cancer. However, the role of circRNAs in ccRCC is still uncertain.

METHODS

The circRNAs microarray (n = 4) was performed to investigate the circRNAs with differential expression in ccRCC tissues. The candidate circRNA was selected based on the cut-off criteria, such as circRNA expression abundance, circRNA size and the design of divergent primers. The circ-transportin-3 (TNPO3) levels in ccRCC tissues were tested by quantitative real-time (qRT)-PCR (n = 110). The characteristics and subcellular localization of circ-TNPO3 were identified via RNase R assay, qRT-PCR and fluorescence in situ hybridization (FISH). Then, we explored the biological roles of circ-TNPO3 in ccRCC via the function experiments in vitro and in vivo. RNA pull-down, RNA immunoprecipitation, bioinformatic analysis, RNA-FISH assays and rescue assays were applied to validate the interactions between circ-TNPO3, insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and serpin family H member 1 (SERPINH1) to uncover the underlying molecular mechanisms of circ-TNPO3.

RESULTS

We detected the obvious downregulation of circ-TNPO3 in ccRCC compared to matched adjacent normal tissues (n = 110). The lower circ-TNPO3 expression was found in ccRCC patients with distant metastasis, higher World Health Organization/International Society of Urologic Pathologists (WHO/ISUP) grade and more advanced tumour T stage. In vitro and in vivo, circ-TNPO3 significantly suppressed the proliferation and migration of ccRCC cells. Mechanistically, we elucidated that circ-TNPO3 directly bound to IGF2BP2 protein and then destabilized SERPINH1 mRNA. Moreover, IGF2BP2/SERPINH1 axis was responsible for circ-TNPO3's function of inhibiting ccRCC metastasis. Epithelial splicing regulatory protein 1 (ESRP1) was probably involved in the biogenesis of circ-TNPO3.

CONCLUSIONS

Circ-TNPO3 can suppress ccRCC progression and metastasis via directly binding to IGF2BP2 protein and destabilizing SERPINH1 mRNA. Circ-TNPO3 may act as a potential target for ccRCC treatment.

Constant light exposure in early life induces m 6A-mediated inhibition of IGF gene family in the chicken

Insulin-like growth factor (IGF) family plays important roles in regulating the development of various organ systems through stimulating cell proliferation and differentiation. Photoperiod is an important factor affecting growth and development in the chicken, yet the effect of constant light exposure in early life on IGF1 and IGF2 expression in the chicken remains unclear. In this study, one-day-old chickens were kept in either constant light (24L:0D, LL) or natural photoperiod (12L:12D, LD) for the first week of life and then maintained in constant light from 8 d to 21 d of age. Constant light exposure in early life reduced mRNA expression of IGF gene family, including mRNA expression of IGF1, IGF2 and IGF2 binding proteins (IGF2BPs), in the hippocampus, hypothalamus and liver of chickens at both 7 d and 21 d of age. Moreover, constant light exposure increased mRNA expression of genes involved in RNA methylation N6-methyladenosine (m 6A) in a tissue-specific manner. Interestingly, higher m 6A on 3'UTR of IGF2 mRNA coincides with lower IGF2 mRNA, indicating a possible role of m 6A in the post-transcriptional regulation of IGF2 expression in the hippocampus, hypothalamus, and liver of chickens. These findings suggest a m 6A-mediated gene regulation of IGF gene family in different organs of chicken and expand our knowledge on mechanism of gene regulation in response to early life experience.

Insulin-like Growth Factor-2 Binding Protein-2 Gene Polymorphisms in Iraqi Patients with Type 2 Diabetes Mellitus

Background: Diabetes mellitus type2 (T2DM) represent a hyperglycemia causing metabolic disease which exists in the peripheral tissues due to incomplete pancreatic insulin secretion or insulin resistance. IGF2BP2 is a protein that is involved in embryogenesis and pancreatic development. Genetic association researches had suggested that the single nucleotide polymorphisms (SNP) spanning IGF2BP2 gene are associated with the progression as well as development of the T2DM. Aim: This study aims to evaluate the association of IGF2BP2 gene polymorphisms (rs4402960 & rs1470579) with T2DM in a sample of Iraqi individuals. Methods: A case-control study has been conducted on 800 participants, they were divided to two equal groups, which are a healthy control group (400) and type 2 diabetic patients (400). Fast blood sugar (FBS), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and HbA1c] measured suitable for both participant groups. IGF2BP2 gene has been genotyped for polymorphisms; rs4402960 and rs1470579 by using the PCR-RFLP technique. Results: There is significant changes in the biochemical parameters in patients group when compared to the control group.The SNP rs4402960 show minor allele frequency of T allele considerably different between the two participating groups (p 0.0013) with 33.6 % in T2DM group. Homo-variant TT shows a significant p <0.0001) odd ratio (4.5) as codominant type. Similarly, dominant and recessive models exert significant (0.02 & <0.0001 respectively) adjusted odd ratio (1.45 & 4.14 respectively). The rs1470579 SNP show a significant (0.024) risk (1.28) of C allele in the patients group than in A allele. The CC genotype in codominant and recessive models show significant (0.03) odd ratio differences (2.03 & 1.96 respectively. The rs1470579 SNP exerts significant differences as codominant model in biochemical features of BMI, FBG, Tgs, VLDL-C, insulin and HOMA-IR. The study power of rs4402960 is 69.5% and rs1470579 is 34.1%. Conclusion: This study confirmed the association of rs4402960 as codominant, dominant and recessive with T2DM significantly. However, rs1470579 is associate as recessive model with T2DM in Iraqi population. 

Age-dependent effects of Igf2bp2 on gene regulation, function, and aging of hematopoietic stem cells in mice

Increasing evidence links metabolism, protein synthesis, and growth signaling to impairments in the function of hematopoietic stem and progenitor cells (HSPCs) during aging. The Lin28b/Hmga2 pathway controls tissue development, and the postnatal downregulation of this pathway limits the self-renewal of adult vs fetal hematopoietic stem cells (HSCs). Igf2bp2 is an RNA binding protein downstream of Lin28b/Hmga2, which regulates messenger RNA stability and translation. The role of Igf2bp2 in HSC aging is unknown. In this study, an analysis of wild-type and Igf2bp2 knockout mice showed that Igf2bp2 regulates oxidative metabolism in HSPCs and the expression of metabolism, protein synthesis, and stemness-related genes in HSCs of young mice. Interestingly, Igf2bp2 expression and function strongly declined in aging HSCs. In young mice, Igf2bp2 deletion mimicked aging-related changes in HSCs, including changes in Igf2bp2 target gene expression and impairment of colony formation and repopulation capacity. In aged mice, Igf2bp2 gene status had no effect on these parameters in HSCs. Unexpectedly, Igf2bp2-deficient mice exhibited an amelioration of the aging-associated increase in HSCs and myeloid-skewed differentiation. The results suggest that Igf2bp2 controls mitochondrial metabolism, protein synthesis, growth, and stemness of young HSCs, which is necessary for full HSC function during young adult age. However, Igf2bp2 gene function is lost during aging, and it appears to contribute to HSC aging in 2 ways: the aging-related loss of Igf2bp2 gene function impairs the growth and repopulation capacity of aging HSCs, and the activity of Igf2bp2 at a young age contributes to aging-associated HSC expansion and myeloid skewing.

RNA-binding proteins and cancer metastasis

RNA-binding proteins (RBPs) can regulate gene expression through post-transcriptionally influencing all manner of RNA biology, including alternative splicing (AS), polyadenylation, stability, and translation of mRNAs, as well as microRNAs (miRNAs) and circular RNAs (circRNAs) processing. There is accumulating evidence reinforcing the perception that dysregulation or dysfunction of RBPs can lead to various human diseases, including cancers. RBPs influence diverse cancer-associated cellular phenotypes, such as proliferation, apoptosis, senescence, migration, invasion, and angiogenesis, contributing to the initiation and development of tumors, as well as clinical prognosis. Metastasis is the leading cause of cancer-related recurrence and death. Therefore, it is necessary to elucidate the molecular mechanisms behind tumor metastasis. In fact, a growing body of published research has proved that RBPs play pivotal roles in cancer metastasis. In this review, we will summarize the recent advances for helping us understand the role of RBPs in tumor metastasis, and discuss dysfunctions and dysregulations of RBPs affecting metastasis-associated processes including epithelial-mesenchymal transition (EMT), migration, and invasion of cancer cells. Furthermore, we will discuss emerging RBP-based strategy for the treatment of cancer metastasis.

Insulin-like growth factor 2 mRNA-binding protein 2-regulated alternative splicing of nuclear factor 1 C-type causes excessive granulosa cell proliferation in polycystic ovary syndrome

Objectives

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder. Insulin‐like growth factor 2 mRNA‐binding protein 2 (IGF2BP2) serves as an HMGA2 target gene to promote the proliferation of granulosa cells (GCs). However, it is still unclear whether IGF2BP2 participates in the pathogenesis of PCOS as RNA binding protein (RBP). In this study, we aimed to elucidate IGF2BP2‐interacting transcripts, global transcriptome together with alternative splicing in GCs to eventually uncover potential mechanisms of PCOS pathogenesis.

Materials and Methods

The expression of IGF2BP2 in GCs from PCOS patients was detected using quantitative reverse transcription PCR (RT‐qPCR) and western blot. We captured IGF2BP2‐interacting transcripts, global transcriptome together with alternative splicing by RNA immunoprecipitation sequencing (RIP‐seq) and RNA sequencing (RNA‐seq). KGN cells transfected with IGF2BP2 overexpressing plasmids and nuclear factor 1 C‐type (NFIC) siRNAs, were applied to CCK‐8, EdU and TUNEL assays.

Results

IGF2BP2 was highly expressed in GCs from PCOS patients. As an RBP, it preferentially bound to the 3′and 5′UTRs of mRNAs with GGAC motif and a newly found GAAG motif. The overexpression of IGF2BP2 changed the transcriptome profile of KGN cells. IGF2BP2 functioned to regulate alternative splicing events and promote cell proliferation through inhibiting exon skipping events of NFIC.

Conclusion

In conclusion, we demonstrated that IGF2BP2 promotes GC proliferation via regulating alternative splicing of NFIC in PCOS. The findings help to better understand the roles of IGF2BP2 in the pathogenesis of PCOS.

Targeting IGF2BP2 Promotes Differentiation of Radioiodine Refractory Papillary Thyroid Cancer via Destabilizing RUNX2 mRNA

Simple Summary

Differentiation therapy is one of the most promising treatment approaches for radioiodine refractory papillary thyroid cancer (RR-PTC). In this study, we found that insulin-like growth factor 2 mRNA-binding protein 2 promoted dedifferentiation of PTC via integrating to 3′-untranslated regions of runt-related transcription factor 2, which bound to the promoter region of sodium/iodide symporter, downregulating its expression.

Abstract

N6-methyladenosine (m6A) regulators play an important role in multiple biological and pathological processes of radioiodine refractory papillary thyroid cancer (RR-PTC). However, the function of m6A regulators in differentiation of RR-PTC remains unclear. In this study, online data, clinical samples, and RR-PTC cell lines (K1 and TPC1) were used to identify the m6A regulators that contributed to the differentiation of RR-PTC. Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) was found to be associated with thyroid-specific genes in online data analyses, and metastatic PTCs with high expression of IGF2BP2 were prone to be ¹³¹I-nonavid in clinical analyses. Furthermore, targeting IGF2BP2 increased ¹²⁵I uptake in RR-PTC cell lines and enhanced the sodium/iodide symporter (NIS) expression. Mechanistically, IGF2BP2 bound to the m6A modification site of runt-related transcription factor 2 (RUNX2) 3′-UTR and enhanced the RUNX2 mRNA stability. Moreover, RUNX2 could bind to the promoter region of NIS to block the differentiation of RR-PTC. Together, these results demonstrated that IGF2BP2 represents a diagnostic marker for RR-PTC, suggesting a novel differentiation therapeutic strategy of targeting IGF2BP2.

First Small-Molecule Inhibitors Targeting the RNA-Binding Protein IGF2BP2/IMP2 for Cancer Therapy

The RNA-binding protein IGF2BP2/IMP2/VICKZ2/p62 is overexpressed in several tumor entities, promotes tumorigenesis and tumor progression, and has been suggested to worsen the disease outcome. The aim of this study is to (I) validate IMP2 as a potential target for colorectal cancer, (II) set up a screening assay for small-molecule inhibitors of IMP2, and (III) test the biological activity of the obtained hit compounds. Analyses of colorectal and liver cancer gene expression data showed reduced survival in patients with a high IMP2 expression and in patients with a higher IMP2 expression in advanced tumors. In vitro target validation in 2D and 3D cell cultures demonstrated a reduction in cell viability, migration, and proliferation in IMP2 knockout cells. Also, xenotransplant tumor cell growth in vivo was significantly reduced in IMP2 knockouts. Different compound libraries were screened for IMP2 inhibitors using a fluorescence polarization assay, and the results were confirmed by the thermal shift assay and saturation-transfer difference NMR. Ten compounds, which belong to two classes, that is, benzamidobenzoic acid class and ureidothiophene class, were validated in vitro and showed a biological target specificity. The three most active compounds were also tested in vivo and exhibited reduced tumor xenograft growth in zebrafish embryos. In conclusion, our findings support that IMP2 represents a druggable target to reduce tumor cell proliferation.