Hidden RNA Tag Drives Paclitaxel Resistance in Bladder Cancer, Study Finds

Bladder urothelial carcinoma remains one of the most challenging malignancies in oncology, a disease whose treatment has been persistently undermined by its remarkable ability to shrug off chemotherapy. Now, a team of researchers in China has uncovered a molecular mechanism that may explain a significant part of that resilience, and their findings point toward a fresh therapeutic target for patients whose tumors stop responding to one of the standard drugs. In a study published in Medical Oncology, investigators from The Second Affiliated Hospital of Nanchang University and collaborating institutions report that an RNA-binding protein called IGF2BP3 fortifies bladder cancer cells against paclitaxel by latching onto a chemically tagged messenger RNA and dramatically prolonging its life inside the cell.

The messenger RNA in question encodes CENPA, or centromere protein A, a specialized histone variant that performs a task no dividing cell can do without: it marks the centromere, the chromosomal anchor point that spindle fibers grip during mitosis to ensure chromosomes are partitioned faithfully between daughter cells. CENPA has long been known to be elevated in a range of tumors, where excess levels contribute to chromosomal instability, aberrant cell division, and aggressive behavior. The new study adds an important layer to that picture by showing that in bladder urothelial carcinoma, CENPA abundance is not simply a matter of how much mRNA is transcribed from the gene, but how long that mRNA survives once it is made—and that survival is controlled by a discrete epitranscriptomic mark.

That mark is N6-methyladenosine, or m6A, the most prevalent internal modification in eukaryotic messenger RNA. Rather than changing the genetic sequence itself, m6A tags act like postal codes, dictating how each transcript is folded, exported, translated, or degraded. The system depends on reader proteins that recognize the tag and act on it. Among the most consequential readers is the IGF2BP family, and in particular IGF2BP3, also known as IMP3, an oncofetal RNA-binding protein that is largely silenced in adult tissues but re-emerges in many cancers, including glioma, hepatocellular carcinoma, renal cell carcinoma, and bladder cancer. Prior work had already linked IGF2BP3 to tumor progression and stem-like behavior in bladder cancer, but its precise contribution to chemotherapy resistance had remained murky.

To dissect that contribution, the research team turned to a pair of well-characterized human bladder urothelial carcinoma cell lines, UMUC3 and T24, alongside a purposefully derived paclitaxel-resistant counterpart of T24, designated T24/R. Paclitaxel works by stabilizing microtubules, throwing a wrench into the mitotic spindle and triggering cell death in rapidly dividing cells. Resistant cells must therefore either alter their division machinery or blunt the death pathways that spindle catastrophe activates. Using a battery of molecular assays—RNA immunoprecipitation to capture physical protein-RNA interactions, methylated RNA immunoprecipitation followed by quantitative PCR to detect the m6A mark itself, and dual-luciferase reporter assays to confirm sequence-specific binding—the researchers established that IGF2BP3 directly recognizes m6A-modified CENPA mRNA in bladder cancer cells.

The functional consequences of that recognition were striking. When the team silenced IGF2BP3, levels of CENPA messenger RNA and its encoded protein fell sharply, an effect the researchers traced to destabilization of the transcript. Actinomycin D chase experiments, a classic method for measuring mRNA half-life, revealed that without IGF2BP3 standing guard, the CENPA message decayed far more rapidly. In practical terms, IGF2BP3 acts as a molecular bodyguard: by docking onto the m6A tag, it shields CENPA mRNA from the cellular degradation machinery, keeping the centromere protein continuously stocked in the tumor cell. Loss of that bodyguard leaves the cancer cell with diminished CENPA supplies and, crucially, a heightened vulnerability to paclitaxel.

That vulnerability translated into measurable changes in tumor behavior. IGF2BP3 knockdown not only increased paclitaxel sensitivity but also curtailed the migration, invasion, and clonogenic capacity of the cancer cells—the repertoire of traits that makes tumors hard to remove and prone to spread. To test whether CENPA was the critical downstream effector rather than an incidental passenger, the researchers ran a rescue experiment: they forced CENPA overexpression in IGF2BP3-silenced cells and found that the malignant capabilities returned, allowing the cells to migrate, invade, and form colonies even under paclitaxel pressure. The m6A dependency of the whole circuit was confirmed with an elegant control. When the researchers mutated the specific m6A site on CENPA mRNA, the rescue effect evaporated, demonstrating that the epitranscriptomic mark is not decorative but essential to the IGF2BP3-CENPA axis.

The story then moved from the dish to the living animal. In xenograft mouse models implanted with paclitaxel-resistant T24/R cells, silencing IGF2BP3 suppressed tumor growth and made the tumors significantly more responsive to paclitaxel treatment. Reintroducing CENPA partially reversed this effect, blunting the gains in drug sensitivity and tumor control. The in vivo results are important because they suggest that the mechanism operates not merely as a cell-culture artifact but as a genuine driver of treatment failure in a physiological setting. They also reinforce the notion that the IGF2BP3-CENPA axis sits upstream of chemoresistance rather than downstream of it, making it a plausible intervention point.

The significance of these findings lies in the convergence of two hot areas of cancer biology: epitranscriptomics and drug resistance. Over the past decade, m6A modification has emerged as a master regulator of cancer-relevant gene expression, with writers, erasers, and readers each offering potential drug targets. IGF2BPs, in particular, have been shown to stabilize transcripts supporting stemness, hypoxia adaptation, metabolism, and immune evasion in tumors. By identifying CENPA mRNA as a specific m6A-dependent target of IGF2BP3 in bladder cancer, the Nanchang-led team has connected this regulatory logic to a clinically painful problem: paclitaxel resistance in urothelial carcinoma, where poor prognosis and chemoresistance remain defining features of advanced disease. CENPA itself has already been implicated in resistance to EGFR inhibitors in lung adenocarcinoma and in suppressing ferroptosis in liver tumors, hinting that epitranscriptomic control of the centromere machinery may be a recurrent theme across cancer types.

The therapeutic implications are twofold. First, IGF2BP3 or its interaction with m6A-tagged CENPA mRNA could serve as a biomarker, helping clinicians identify patients whose tumors are likely to resist paclitaxel and who might benefit from alternative regimens or combination strategies. Second, pharmacologically disrupting the IGF2BP3-CENPA axis—whether by blocking the protein-RNA interaction, depleting IGF2BP3, or targeting upstream m6A machinery—could resensitize resistant tumors to existing chemotherapy, effectively converting nonresponders into responders. The study’s authors, led by HanJie Yi, YongQing Han, and corresponding author ShanFeng Li, suggest that targeting this axis may provide a novel strategy to overcome chemoresistance in bladder urothelial carcinoma. Substantial work remains before such strategies reach patients: the findings derive from cell lines and xenografts, and candidate inhibitors of m6A readers are only beginning to enter clinical development. Yet the study offers a clear mechanistic narrative for how bladder cancer cells weaponize a chemical tag on their own messenger RNA to endure one of medicine’s oldest spindle poisons—and in doing so, it hands researchers a precise molecular handle to pry that endurance apart.

Subject of Research: m6A-dependent stabilization of CENPA mRNA by IGF2BP3 as a mechanism of paclitaxel resistance in bladder urothelial carcinoma

Article Title: IGF2BP3 enhances paclitaxel resistance in bladder urothelial carcinoma by recognizing m6A-modified CENPA mRNA

Article References: Yi, H., Han, Y., Wang, X., Li, Q., Xiong, L., & Li, S. (2026). IGF2BP3 enhances paclitaxel resistance in bladder urothelial carcinoma by recognizing m6A-modified CENPA mRNA. Medical Oncology, 43(10), Article 278. https://doi.org/10.1007/s12032-026-03383-7

Image Credits: AI Generated

DOI: 10.1007/s12032-026-03383-7

Keywords: bladder urothelial carcinoma, IGF2BP3, CENPA, m6A modification, paclitaxel resistance, mRNA stability, chemoresistance, epitranscriptomics, RNA-binding protein, cancer therapeutic resistance, urological cancer, xenograft models