Circular RNAs (circRNAs) have recently emerged as critical players in cancer biology, serving not merely as byproducts of splicing but as active regulators of gene expression. Their unique closed-loop structure endows them with remarkable stability, allowing them to act as molecular sponges that sequester microRNAs (miRNAs), thus indirectly influencing protein translation. This latest research focuses on one such circRNA, circ_001024—previously obscure yet now found to be highly overexpressed in RCC tumors.

Delving deep into circ_001024’s architecture, researchers employed Sanger sequencing complemented by RNase R digestion assays to validate its circular nature. Actinomycin D treatment further confirmed its resilience and prolonged half-life compared to linear counterparts. The robust presence of circ_001024 within RCC cells, primarily localized in the cytoplasm as revealed by Fluorescence in situ Hybridization (FISH), hints at its functional engagement in post-transcriptional gene regulatory mechanisms.

A series of quantitative real-time PCR experiments demonstrated significantly elevated levels of circ_001024 in tumor samples relative to adjacent normal tissue. Functional assays revealed that enforcing circ_001024 expression stimulated RCC cell proliferation, migration, and invasion—hallmarks of cancer aggressiveness. Conversely, targeted knockdown attenuated these malignant properties, suggesting a causative role of circ_001024 in facilitating tumor progression.

The mechanistic underpinnings became clearer with bioinformatics analyses pinpointing miR-145-3p as a potential interacting miRNA. Confirmatory dual-luciferase reporter assays elucidated a reciprocal binding relationship: circ_001024 acts as a miRNA “sponge,” competitively inhibiting miR-145-3p. This microRNA, known for tumor-suppressive functions, typically represses a set of oncogenic targets, including the GLUT5 protein—a key facilitator in cellular fructose uptake.

Subsequent RNA pull-down assays and rescue experiments cemented the axis of circ_001024, miR-145-3p, and GLUT5 in RCC pathophysiology. Overexpressing miR-145-3p partially reversed the oncogenic effects driven by circ_001024, corroborating that circ_001024’s malignant influence is mediated through miR-145-3p sequestration. Western blot analyses further revealed GLUT5 protein levels mirroring circ_001024 expression, linking enhanced fructose metabolism to RCC advancement.

Intriguingly, clinicopathological correlation studies depicted GLUT5 expression as significantly associated with the WHO/ISUP grading of RCC tumors—a critical determinant of malignancy and prognosis. This association, however, did not extend to patient age, gender, tumor size, or TNM staging, underscoring GLUT5’s potential role as a biomarker for tumor aggressiveness rather than tumor burden.

These revelations underscore a novel metabolic regulatory mechanism in RCC, where circ_001024 modulates the metabolic landscape through GLUT5 by titrating miR-145-3p availability. The study situates metabolic adaptation at the nexus of RCC progression, highlighting fructose metabolism as a previously underappreciated contributor to renal carcinogenesis.

Beyond the molecular implications, the translational potential of these findings is vast. Therapeutically targeting circ_001024—either by disrupting its miRNA-binding capacity or by enhancing miR-145-3p function—could impair GLUT5-mediated metabolic pathways, potentially starving RCC cells of vital nutrients required for rapid growth and invasiveness.

Moreover, the study’s advanced methodological framework combines transcriptomic validations, functional perturbations, and clinical data integration—establishing a robust template for future circRNA investigations in cancer biology. These comprehensive approaches ensure that the observed effects are not artifacts but reflect genuine biological processes relevant to tumor progression.

As RCC remains notoriously resistant to conventional therapies, the identification of circ_001024 and its interactive network with miR-145-3p and GLUT5 offers fresh hope. It invites a paradigm shift towards targeting RNA-based regulatory circuits and metabolic dependencies in cancer, a strategy that may eventually translate into personalized and more effective treatment modalities.

In conclusion, this pioneering work unravels the sophisticated endogenous competition between circRNAs and miRNAs in RCC, highlighting circ_001024’s role as a molecular decoy that subverts miR-145-3p suppression of GLUT5. This intricate regulatory mechanism not only advances our understanding of RCC pathogenesis but also charts a promising course for future research and therapeutic innovation.

Subject of Research:
The regulatory role of circ_001024 in renal cell carcinoma progression via competitive binding to miR-145-3p and consequent modulation of GLUT5.

Article Title:
Role and mechanism of circ_001024 endogenous competition for miR-145-3p targeting to regulate GLUT5 in RCC

Article References:
Zhao, L., Xu, J., Li, D. et al. Role and mechanism of circ_001024 endogenous competition for miR-145-3p targeting to regulate GLUT5 in RCC. BMC Cancer 25, 1713 (2025). https://doi.org/10.1186/s12885-025-14878-3

Image Credits: Scienmag.com

DOI:
05 November 2025

Keywords:
Renal cell carcinoma, circular RNA, circ_001024, miR-145-3p, GLUT5, fructose metabolism, tumor progression, RNA sponging, molecular oncology

Colorectal cancer’s complex biology has long challenged scientists seeking to unravel the mechanisms behind its aggressive behavior. Recent years have brought increasing attention to non-coding RNAs, especially circular RNAs (circRNAs), which are covalently closed RNA loops exhibiting remarkable stability and diverse regulatory functions. Unlike linear RNAs, circRNAs escape exonuclease degradation due to their closed-loop structure, sustaining persistent cellular effects. Within this context, circ_0000847 emerges as a compelling player modulating gene expression through interaction with RNA-binding proteins.

The core of this study focuses on the interaction between circ_0000847 and the insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), a key RNA-binding protein implicated in mRNA stabilization and translational control. IGF2BP2 has garnered significant attention for its role in oncogenesis by stabilizing mRNAs of oncogenes and promoting their expression. By binding to IGF2BP2, circ_0000847 enhances the stability of insulin-like growth factor 2 (IGF2) mRNA, thereby amplifying its expression within colorectal cancer cells.

IGF2 itself is a well-recognized growth factor involved in embryonic development and cancer physiology, acting through the IGF1 receptor and related signaling pathways to promote proliferation and survival. Increased IGF2 expression correlates with poor prognosis in various cancers, including colorectal malignancies. The preservation of IGF2 mRNA stability via the circ_0000847 and IGF2BP2 axis suggests an important mechanism by which tumors may maintain elevated growth signals.

The research team employed an array of molecular biology techniques to meticulously dissect this axis. Techniques such as RNA immunoprecipitation, reporter assays, and gene knockdown experiments demonstrated that circ_0000847 primarily functions by sequestering IGF2BP2, resulting in enhanced binding affinity of this protein to IGF2 mRNA. This stabilization prevents its degradation and prolongs the presence of growth-promoting transcripts, culminating in increased protein translation.

Functional assessments in colorectal cancer cell lines further elucidated the phenotypic consequences of this interaction. Cells overexpressing circ_0000847 exhibited markedly increased migratory and invasive capabilities compared to controls. These phenotypes are hallmarks of metastatic potential, underscoring circ_0000847’s critical contribution to cancer cell dissemination beyond the primary tumor site, which remains a major challenge in colorectal cancer management.

Perhaps most strikingly, the study highlights how circ_0000847 influences the epithelial-mesenchymal transition (EMT), a biological process where polarized epithelial cells acquire mesenchymal, fibroblast-like properties conducive to migration. EMT is pivotal for cancer metastasis, facilitating detachment, invasion of surrounding tissues, and eventual seeding of distant organs. Circ_0000847’s capacity to intensify EMT was evident through enhanced expression of mesenchymal markers and concurrent repression of epithelial markers, highlighting its role in remodeling the cellular architecture toward a more aggressive phenotype.

Insights into the molecular underpinnings of circ_0000847’s function offer exciting avenues for therapeutic interventions. Targeting circRNAs is notoriously challenging due to their stability and abundance, but strategies aimed at disrupting their interaction with key RNA-binding proteins like IGF2BP2 may hold promise. Such approaches could destabilize oncogenic mRNAs and attenuate signaling pathways that drive colorectal tumor progression.

Considering the translational implications, biomarkers based on circ_0000847 expression or the circ_0000847–IGF2BP2 interaction could serve as prognostic tools, guiding clinical decisions and identifying patients at higher risk of metastasis. This bears significance as current colorectal cancer prognostication largely depends on pathological staging, which may not fully capture the molecular aggressiveness of individual tumors.

Furthermore, this study enhances our understanding of the non-coding RNA landscape in cancer biology, reinforcing the importance of RNA-protein interactions beyond classical gene regulation paradigms. The circ_0000847/IGF2BP2/IGF2 axis exemplifies how complex RNA networks orchestrate critical cellular processes that malignant cells hijack for survival and spread.

In the broader spectrum of cancer research, these findings underscore the need for deeper investigation into circRNA-mediated mechanisms. The stability and functional diversity of circRNAs position them as both compelling biological regulators and untapped therapeutic targets. As more circRNAs with oncogenic or tumor-suppressive roles are identified, personalized cancer treatment may soon incorporate modulation of these molecules.

This discovery also challenges us to rethink RNA-centric interventions in oncology. Traditional therapies have focused heavily on targeting proteins, but RNA-based therapeutics—such as antisense oligonucleotides, small interfering RNAs, and CRISPR-based editing—are rapidly evolving. CircRNAs like circ_0000847 might be susceptible to tailored RNA interference strategies that disrupt their oncogenic partnerships.

Notably, the interrogation of EMT-driven pathways via circRNA research opens potential cross-talk understandings with other metastasis mechanisms, including tumor microenvironment alterations and immune evasion. Further studies exploring how circ_0000847 and its associated network interact with these processes could reveal compounded effects or novel vulnerabilities.

The clinical relevance of this circRNA-mediated regulatory axis is amplified by colorectal cancer’s global burden, with metastatic disease being the leading cause of patient mortality. Intervening in the molecular events that facilitate early invasion and dissemination could dramatically improve outcomes for affected individuals.

In summary, Zhang and Zheng’s study presents compelling evidence that circ_0000847, through binding to IGF2BP2, acts as a critical promoter of colorectal cancer metastasis by stabilizing IGF2 mRNA and facilitating EMT. This breakthrough enhances our molecular understanding of colorectal cancer progression and opens promising pathways for therapeutic targeting and prognostic assessment.

As research into non-coding RNAs expands, circ_0000847’s role uniquely positions it at the forefront of novel cancer biology discoveries. The combination of robust molecular techniques and clinically relevant functional assays highlights the rigorous approach underpinning this advancement. Future efforts to translate these findings from bench to bedside will be crucial in combating colorectal cancer’s morbidity and mortality.

Continued exploration of circRNAs like circ_0000847 promises to redefine how we conceptualize RNA functions within oncogenic networks, perfectly illustrating the complexity and opportunity inherent in cancer molecular biology.

Subject of Research:
The role of circ_0000847 in promoting migration, invasion, and epithelial-mesenchymal transition (EMT) in colorectal cancer through interaction with IGF2BP2 to stabilize IGF2 mRNA.

Article Title:
Circ_0000847 promotes the migration, invasion, and EMT process in colorectal cancer through binding to IGF2BP2 to enhance IGF2 mRNA stability.

Article References:

Zhang, A., Zheng, Y. Circ_0000847 promotes the migration, invasion, and EMT process in colorectal cancer through binding to IGF2BP2 to enhance IGF2 mRNA stability. Med Oncol 42, 436 (2025). https://doi.org/10.1007/s12032-025-02877-0

Image Credits:
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