Ribosomal RNA Tag and a Detox Enzyme Form a Deadly Cancer Survival Circuit

Deep inside every cell that makes a protein, a tiny chemical tag is being stamped onto the ribosome itself, and cancer cells have learned to love it. A new review published in Molecular Biology Reports by Abinash Nayak and Sudhansu Sekhar Nishank of Utkal University pulls together a decade of scattered discoveries into a single, striking picture: an epitranscriptomic circuit linking the RNA methyltransferase METTL5 to the detox enzyme MGST1 may be one of the reasons some tumors refuse to die under therapy. The work, which synthesizes findings most firmly established in hepatocellular carcinoma, argues that this axis controls not just how fast tumors grow, but how they evade immune attack and resist a form of cell death called ferroptosis that researchers have long hoped to exploit against cancer.

To understand why this matters, it helps to start with what METTL5 actually does. It belongs to a family of methyltransferase-like proteins that chemically decorate RNA molecules, a field known as epitranscriptomics because it adds a layer of regulation on top of the genetic code itself. Unlike its famous cousin METTL3, which methylates messenger RNAs, METTL5 works on the protein-building machinery directly. It deposits an N6-methyladenosine mark, known as m6A, on a specific adenosine called A1832 within the 18S ribosomal RNA, right in the decoding center of the small ribosomal subunit where messenger RNA codons are matched to transfer RNA anticodons. That single methyl group, stabilized in place by METTL5’s obligate cofactor TRMT112, subtly changes how the ribosome translates certain cancer-promoting messenger RNAs, giving oncogenic transcripts a translation advantage that normal transcripts do not enjoy.

The consequences of this ribosomal tuning are now documented across a remarkable range of tumors. In breast cancer, METTL5-driven methylation promotes translation initiation and cell growth. In pancreatic cancer and oral squamous cell carcinoma, the enzyme boosts the Myc pathway by enhancing translation of the c-Myc oncogene, one of the most notorious drivers of uncontrolled proliferation. In lung squamous cell carcinoma, METTL5 promotes tumorigenesis through DEPDC1, while in intrahepatic cholangiocarcinoma it accelerates progression by ramping up oncogenic mRNA translation. In osteosarcoma, METTL5 methylates the mRNA of UBE3C, which suppresses ferroptosis by inducing ubiquitination of the protein AHNAK. Each study points to the same principle: by remodeling the ribosome’s chemical surface, METTL5 selectively amplifies the production of the proteins a tumor needs most.

But the review’s central argument goes a step further, connecting this translation machinery to a metabolic enzyme with a very different job. Microsomal Glutathione S-Transferase 1, or MGST1, is a membrane-embedded member of the MAPEG family that detoxifies reactive molecules and helps maintain redox balance within cells. Recent work, most directly in hepatocellular carcinoma, identified MGST1 as a key downstream effector of METTL5: when METTL5 is active, MGST1 is produced in quantities that allow cancer cells to suppress ferroptosis, an iron-dependent form of cell death driven by the accumulation of lipid peroxides in cellular membranes. In other words, the ribosomal methyl tag ultimately helps tumors survive an oxidative assault, whether that assault comes from their own metabolism or from chemotherapy and radiotherapy.

The ferroptosis connection deserves particular attention because it links two of the hottest topics in cancer biology. Ferroptosis occurs when polyunsaturated fatty acids in membrane phospholipids are oxidized faster than cellular antioxidant systems can repair them, leading to catastrophic membrane rupture. Cancer cells defend themselves through several redundant systems, including the glutathione peroxidase GPX4, the cystine importer SLC7A11 regulated by the transcription factor Nrf2, and, as the review emphasizes, MGST1 itself. Studies compiled in the review show that MGST1 acts as a redox-sensitive repressor of ferroptosis in pancreatic cancer cells, that blocking MGST1 makes non-small cell lung cancer cells sensitive to radiotherapy by enhancing ALOX15-mediated lipid peroxidation, and that the transcription factor ZNF384 activates MGST1 to confer resistance to the glioma drug temozolomide. In gastric cancer, MGST1 expression is associated with poor prognosis and enhances Wnt/beta-catenin signaling through AKT regulation while simultaneously inhibiting ferroptosis.

The review also maps the signaling cascades that weave through this axis, and they read like a wiring diagram of tumor aggression. Upstream and downstream of METTL5, the authors trace the c-Myc/FBXW7 circuit that couples oncogenic translation to protein degradation control, the TGF-beta/SMAD pathway that drives epithelial-mesenchymal transition and metastasis, the Akt/GSK-3beta axis that promotes survival and metabolism, the Nrf2/SLC7A11 antioxidant program that imports cystine for glutathione synthesis, and the ATF4-dependent stress response that tumor cells use to prevent T cell-induced ferroptosis. In ovarian cancer, for example, tumor-intrinsic METTL5 modulates ATF4 translation specifically to stop cytotoxic T lymphocytes from pushing tumor cells into ferroptosis, a finding that directly connects ribosomal methylation to the immune battlefield.

That immune dimension may prove to be the most clinically consequential. Several studies assembled in the review show that METTL5 helps tumors hide from the immune system. Knocking down METTL5 in hepatocellular carcinoma cells inhibits the Myc pathway, downregulates PD-L1 expression, and reduces immune escape, suggesting the enzyme helps tumors display the molecular do-not-eat signal that checkpoint inhibitors target. More recent work indicates METTL5 enables immune evasion of liver cancer through regulation of chemokine mRNA translation, and it promotes the release of neutrophil extracellular trap networks that shape the tumor microenvironment in hepatocellular carcinoma. Perhaps most provocatively, depletion of the rRNA methyltransferase enhances anti-tumor immune responses by generating neoantigens from cryptic translation, meaning that losing METTL5 causes ribosomes to translate previously hidden stretches of RNA into novel peptide fragments that the immune system can recognize as foreign.

Translating these mechanisms into treatments is the review’s final, and most cautious, chapter. The authors evaluate several therapeutic strategies: small-molecule inhibitors modeled on the emerging generation of methyltransferase drugs such as the METTL3 inhibitors STM2457, STC-15, and EP652, which have shown preclinical efficacy in liquid and solid tumor models; RNA interference approaches to silence METTL5 or MGST1 directly; CRISPR-based strategies for precision targeting; and rational combinations with immune checkpoint blockade, which the ferroptosis and neoantigen data suggest could be particularly synergistic. Because MGST1 sits downstream and is itself druggable, inhibiting it could sensitize tumors to ferroptosis-inducing therapies even when upstream targeting is impractical. The review is careful to note, however, that the METTL5-MGST1 link is most directly established in hepatocellular carcinoma, and that in other cancer types METTL5’s effects on ferroptosis and immunity may operate through MGST1-independent mechanisms.

There are also safety questions that any clinical translation must confront. METTL5 is not exclusively a cancer gene: heterozygous loss-of-function variants in humans are associated with intellectual disability, METTL5 deficiency causes impaired sperm motility through defective 18S rRNA methylation in both humans and mice, and the enzyme has normal roles in stem cell biology and, in plants such as Arabidopsis, in regulating translation broadly. A recent study in Proceedings of the National Academy of Sciences adds another twist, showing that p53 can override METTL5 loss-induced tumor suppression through mitochondrial respiration, hinting that the efficacy of targeting this axis may depend on the genetic background of each tumor. Meanwhile, METTL5 modulation has been shown to alleviate airway allergy by reshaping the epigenetic profile of M2 macrophages, underscoring that the enzyme’s reach extends well beyond oncology.

What emerges from the review is a coherent biological story with genuine therapeutic promise and equally genuine caveats. A single methyl group on ribosomal RNA, placed by an enzyme that most clinicians have never heard of, appears to influence which proteins a tumor manufactures, how it withstands oxidative death, and how invisible it remains to patrolling immune cells. If the METTL5-MGST1 axis holds up under experimental scrutiny across tumor types, and if selective inhibitors can be developed with acceptable toxicity, it could offer a new entry point against the therapy-resistant cancers that currently defeat both chemotherapy and immunotherapy. For now, the review serves as both a synthesis and a challenge: a detailed molecular map of a circuit that cancer cells depend on, and an invitation for the drug discovery community to find the tools to break it.

Subject of Research: The METTL5–MGST1 epitranscriptomic signaling axis in tumor progression, ferroptosis resistance, and cancer therapy

Article Title: Targeting the METTL5–MGST1 axis for cancer therapy: molecular mechanisms and therapeutic implications

Article References: Nayak, A., & Nishank, S. S. (2026). Targeting the METTL5–MGST1 axis for cancer therapy: molecular mechanisms and therapeutic implications. Molecular Biology Reports, 53(1), Article 1612. https://doi.org/10.1007/s11033-026-12757-z

Image Credits: AI Generated

DOI: 10.1007/s11033-026-12757-z

Keywords: METTL5, MGST1, m6A, 18S rRNA methylation, epitranscriptomics, ferroptosis, hepatocellular carcinoma, cancer therapy, PD-L1, immune evasion, ribosome, TRMT112