The Oncogenic Functions of Insulin-like Growth Factor 2 mRNA-Binding Protein 3 in Human Carcinomas

IGF2BP3 loss inhibits cell progression by upregulating has_circRNA_103820, and hsa_circRNA_103820-encoded peptide inhibits cell progression by inactivating the AKT pathway in lung cancer

N6-methyladenosine (m6A) modification and m6A-related RNA-binding proteins (RBPs) play vital roles in various aspects of circRNA metabolism. Hsa_circRNA_103820 is implicated in the pathogenesis of multiple cancers, including lung cancer (LC). Moreover, bioinformatics analysis has suggested that hsa_circRNA_103820 possesses potential peptide-coding ability. Thus, we aimed to investigate the function and peptide-coding potential of hsa_circRNA_103820 in this study. Cell viability, apoptosis rate, and migratory and invasive abilities were assessed using CCK-8, flow cytometry, and transwell assays, respectively. Hsa_circRNA_103820 level was measured using RT-qPCR assay, and the interaction between hsa_circRNA_103820 and IGF2BP3 was examined through RIP and RT-qPCR assays. The coding ability of hsa_circRNA_103820 and protein levels were determined through western blot assay. The results showed that hsa_circRNA_103820 reduced cell viability, attenuated cell migratory and invasive abilities, and promoted cell apoptosis in LC. IGF2BP3 negatively regulated hsa_circRNA_103820 expression and interacted with it. Hsa_circRNA_103820 knockdown alleviated si-IGF2BP3-mediated anti-viability, anti-migration, anti-invasion, and pro-apoptosis effects in LC cells. Moreover, a 188-amino acid (aa) peptide encoded by hsa_circRNA_103820 decreased cell viability, facilitated cell apoptosis, and inhibited cell migration and invasion in LC. Collectively, hsa_circRNA_103820, regulated by IGF2BP3, encodes a 188-aa peptide and inhibits the malignant progression of LC cells by inhibiting the AKT pathway.

Knockdown of RNA-binding protein IMP3 suppresses oral squamous cell carcinoma proliferation by destabilizing E2F5 transcript

The expression level of RNA-binding proteins (RBPs) is dysregulated in oral squamous cell carcinoma (OSCC) and other types of cancer. Among the RBPs, IMP3 is involved in the progression of OSCC. However, the regulation of mRNA fate by IMP3 in OSCC remains less understood. We analyzed the expression level of IMP3 and E2F5 in OSCC tissues and cell lines by immunohistochemistry, qRT-PCR and Western blot. Subsequently, to further investigate the effect of IMP3 on E2F5 expression, we used siRNAs to silence IMP3 expression in OSCC cell lines SCC-25 and SCC-4. The binding site of E2F5 mRNA and IMP3 was confirmed by RNA immunoprecipitation (RIP). Finally, the function of IMP3 and E2F5 was investigated in viro and in xenograft mouse models. Here we report a positive correlation between IMP3 and E2F5 expression in OSCC, which are involved in cell proliferation and cell cycle. Mechanistically, E2F5 mRNA is bound by IMP3 protein, and silencing it leads to a shortened mRNA half-life and reduced protein expression. Also, knockdown of IMP3 inhibited allograft tumor progression in vivo. These studies reveal the molecular mechanism by which IMP3 regulates E2F5 mRNA stability and identify IMP3/E2F5 as a potential therapeutic target in OSCC.

Diagnostic Challenges during Inflammation and Cancer: Current Biomarkers and Future Perspectives in Navigating through the Minefield of Reactive versus Dysplastic and Cancerous Lesions in the Digestive System

In the setting of pronounced inflammation, changes in the epithelium may overlap with neoplasia, often rendering it impossible to establish a diagnosis with certainty in daily clinical practice. Here, we discuss the underlying molecular mechanisms driving tissue response during persistent inflammatory signaling along with the potential association with cancer in the gastrointestinal tract, pancreas, extrahepatic bile ducts, and liver. We highlight the histopathological challenges encountered in the diagnosis of chronic inflammation in routine practice and pinpoint tissue-based biomarkers that could complement morphology to differentiate reactive from dysplastic or cancerous lesions. We refer to the advantages and limitations of existing biomarkers employing immunohistochemistry and point to promising new markers, including the generation of novel antibodies targeting mutant proteins, miRNAs, and array assays. Advancements in experimental models, including mouse and 3D models, have improved our understanding of tissue response. The integration of digital pathology along with artificial intelligence may also complement routine visual inspections. Navigating through tissue responses in various chronic inflammatory contexts will help us develop novel and reliable biomarkers that will improve diagnostic decisions and ultimately patient treatment.

IGF2BP3 Enhances the Growth of Hepatocellular Carcinoma Tumors by Regulating the Properties of Macrophages and CD8+ T Cells in the Tumor Microenvironment

Background and Aims

Overexpression of IGF2BP3 is associated with the prognosis of hepatocellular carcinoma (HCC). However, its role in regulating tumor immune microenvironment (TME) is not well characterized. Here, we investigated the effects of IGF2BP3 on macrophages and CD8+ T cells within the TME of HCC.

Methods

The relationship between IGF2BP3 and immune cell infiltration was analyzed using online bioinformatics tools. Knockout of IGF2BP3 in mouse hepatoma cell line Hepa1-6 was established using CRISPR/Cas9 technology. In vitro cell coculture and subcutaneously implanted hepatoma mice model were used to explore the effects of IGF2BP3 on immune cells. Expression of CCL5 or transforming growth factor beta 1 (TGF-β1) was detected with quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. The binding of IGF2BP3 and its target RNA was verified by trimolecular fluorescence complementation system and RNA immunoprecipitation followed by quantitative or semiquantitative polymerase chain reaction.

Results

IGF2BP3 expression was elevated in HCC and was positively correlated with macrophage infiltration. Patients with higher IGF2BP3 expression and lower macrophage infiltration had a better survival rate. We found that IGF2BP3 could bind to the mRNA of CCL5 or TGF-β1, increasing their expression, and inducing macrophage infiltration and M2 polarization while inhibiting the activation of CD8+ T cells. Furthermore, inhibition of IGF2BP3 combined with anti-CD47 antibody treatment significantly suppressed the growth of hepatoma in Hepa1-6 xenograft tumor mice.

Conclusions

IGF2BP3 promoted the infiltration and M2-polarization of macrophages and suppressed CD8+ T activation by enhancing CCL5 and TGF-β1 expression, which facilitated the progression of Hepa1-6 xenograft tumor.

Unveiling the protein signature of the human osteosarcoma 3AB-OS cancer stem cell line

In cancer research today, one of the major challenges is the eradication of cancer stem cells (CSCs) within the tumor mass. These cells play a crucial role in initiating, growing, and maintaining the tumor. Evidence has demonstrated the presence and significance of CSCs in the development and progression of osteosarcoma (OS). However, our understanding of the specific markers for OS stem cells remains limited. In this study, we aim to identify distinct biomarkers for this cell population by conducting a proteomic analysis comparing OS stem cells to their non-stem counterparts. Our investigation focuses on a particular cell line called 3AB-OS, which exhibits stem-like characteristics, and its differentiated parental cell line, MG63. Through this research, we discovered 63 proteins exclusively expressed in 3AB-OS cells. Applying an in silico bioinformatics approach, we determined that the majority of these proteins are associated with RNA metabolism. Additionally, we identified a potential correlation between the insulin-like growth factor-binding proteins (IGF2BPs) signaling pathway and the tumorigenic and stemness features observed in 3AB-OS cells.

Parkin regulates IGF2BP3 through ubiquitination in the tumourigenesis of cervical cancer

BACKGROUND

Insulin-like growth Factor 2 mRNA-binding protein 3 (IGF2BP3) is a highly conserved RNA-binding protein and plays a critical role in regulating posttranscriptional modifications.

METHODS

Immunoprecipitation was used to examine the interaction of Parkin and IGF2BP3. Mass spectrometry was performed to identify the ubiquitination sites of IGF2BP3. RNA-immunoprecipitation was conducted to examine the target genes of IGF2BP3. Xenograft mouse model was constructed to determine the tumorigenesis of IGF2BP3.

RESULTS

IGF2BP3 expression is negatively correlated with Parkin expression in human cervical cancer cells and tissues. Parkin directly interacts with IGF2BP3, and overexpression of Parkin causes the proteasomal degradation of IGF2BP3, while knockdown of PARK2 increases the protein levels of IGF2BP3. Mechanistically, in vivo and in vitro ubiquitination assays demonstrated that Parkin is able to ubiquitinate IGF2BP3. Moreover, the ubiquitination site of IGF2BP3 was identified at K213 in the first KH domain of IGF2BP3. IGF2BP3 mutation results in the loss of its oncogenic function as an m6A reader, resulting in the inactivation of the phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signalling pathways. In addition, IGF2BP3 mutation results in the attenuation of Parkin-mediated mitophagy, indicating its inverse role in regulating Parkin. Consequently, the tumourigenesis of cervical cancer is also inhibited by IGF2BP3 mutation.

CONCLUSION

IGF2BP3 is ubiquitinated and regulated by the E3 ubiquitin ligase Parkin in human cervical cancer and ubiquitination modification plays an important role in modulating IGF2BP3 function. Thus, understanding the role of IGF2BP3 in tumourigenesis could provide new insights into cervical cancer therapy.

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.

RNA-Binding Proteins in Bladder Cancer

RNA-binding proteins (RBPs) are key regulators of transcription and translation, with highly dynamic spatio-temporal regulation. They are usually involved in the regulation of RNA splicing, polyadenylation, and mRNA stability and mediate processes such as mRNA localization and translation, thereby affecting the RNA life cycle and causing the production of abnormal protein phenotypes that lead to tumorigenesis and development. Accumulating evidence supports that RBPs play critical roles in vital life processes, such as bladder cancer initiation, progression, metastasis, and drug resistance. Uncovering the regulatory mechanisms of RBPs in bladder cancer is aimed at addressing the occurrence and progression of bladder cancer and finding new therapies for cancer treatment. This article reviews the effects and mechanisms of several RBPs on bladder cancer and summarizes the different types of RBPs involved in the progression of bladder cancer and the potential molecular mechanisms by which they are regulated, with a view to providing information for basic and clinical researchers.

Knockdown of m6A Reader IGF2BP3 Inhibited Hypoxia-Induced Cell Migration and Angiogenesis by Regulating Hypoxia Inducible Factor-1α in Stomach Cancer

Hypoxia is a common feature of solid tumors including stomach cancer (SC) and is closely associated with cancer malignant progression. N6-methyladenosine (m6A), a common modification on RNA, is involved in the regulation of RNA fate and hypoxic responses in cancers. However, the interaction between m6A reader insulin-like growth factor-II mRNA-binding protein 3 (IGF2BP3) and SC hypoxic microenvironment is poorly defined. In the present study, expression levels of IGF2BP3 and hypoxia inducible factor-1α (HIF1A) were examined by bioinformatics analysis and RT-qPCR and western blot assays. Cell migratory ability was assessed through Transwell and wound healing assays. The angiogenic potential was evaluated by VEGF secretion, tube formation, and chick embryo chorioallantoic membrane (CAM) assays. The interaction between IGF2BP3 and HIF1A was explored using bioinformatics analysis and RIP and luciferase reporter assays. The results showed that IGF2BP3 and HIF1A were highly expressed in SC tissues and hypoxia-treated SC cells. IGF2BP3 knockdown inhibited hypoxia-induced cell migration and angiogenesis in SC. IGF2BP3 positively regulated HIF1A expression by directly binding to a specific m6A site in the coding region of HIF1A mRNA in SC cells. HIF1A overexpression abrogated the effects of IGF2BP3 knockdown on hypoxia-induced cell migration and angiogenesis in SC. In conclusion, IGF2BP3 knockdown inhibited hypoxia-induced cell migration and angiogenesis by down-regulating HIF1A in SC.