How cancer cells evade treatment: mechanisms of epigenetic plasticity and strategies to target it
Treatment resistance that genetic mutations alone cannot fully explain
Epigenetic plasticity—the ability of cancer cells to alter gene expression and cell state under treatment pressure—supports treatment resistance. A review published in Molecular Biomedicine describes this adaptive process in terms of interactions among DNA methylation, histone modifications, chromatin remodeling, and non-coding RNAs. The paper synthesizes mechanisms and therapeutic development strategies from the existing literature; it does not report new experiments or clinical trial results.
Resistance that limits chemotherapy, targeted therapy, and immunotherapy cannot be fully explained by fixed genetic mutations alone. Treatment responses can differ even among cells with similar genetic backgrounds, and some drug-tolerant states can reverse after treatment is stopped. Drawing on the concept of an “epigenetic landscape” that describes cell fate, the authors examine how cancer cells establish and maintain survival states under treatment stress.
Adaptive pathways shaped by four regulatory layers
The four layers described in the review regulate gene expression in distinct ways. DNA methylation can suppress expression when it accumulates at the promoter of a particular gene. Histone modifications affect gene activity by changing chemical marks on the proteins around which DNA is wrapped. Chromatin-remodeling complexes regulate DNA accessibility by moving or rearranging nucleosomes, which consist of DNA and histones. Non-coding RNAs participate in expression control through interactions with other RNAs or proteins.
These regulatory layers are interconnected and can help silence tumor-suppressive programs or activate bypass pathways that sustain survival when a signaling pathway is blocked. The effects of epigenetic changes, however, depend on the gene and treatment context. The review explains that suppressing DNA-repair genes can make cells vulnerable to certain treatments, while subsequent restoration of their expression may lead to resistance.
A representative example of adaptation is the drug-tolerant persister (DTP) cell. Some cells that survive initial treatment persist in a slow-growing state with reorganized metabolism. The review explains that chromatin-state changes support this survival and that temporary adaptation may provide a foothold for more stable resistance later. Reversible drug tolerance should be distinguished from stably maintained resistance. The review also considers impaired immune-cell function and changes in the stroma surrounding the tumor, in addition to cancer cells themselves.
Combination strategies against resistance and challenges for clinical validation
The goal of therapeutic development is to exploit this plasticity as a vulnerability. The review discusses strategies that combine drugs regulating DNA methylation or histone modifications with existing treatments in an effort to restore cancer-cell drug sensitivity. It also introduces targeted protein degradation, which removes regulatory proteins themselves, and epigenetic editing, which modulates gene expression at specific sites without changing the DNA sequence. These approaches differ in mechanism and stage of development; they should not be interpreted as established treatments that overcome resistance across cancers.
Clinical application still faces challenges including combination toxicity, appropriate dosing sequences and intervals, and biomarkers to identify patients likely to respond. Some existing drugs have limited single-agent activity in solid tumors, while editing technologies must also address delivery to tumors and changes at unintended sites. Large prospective clinical trials demonstrating improved patient outcomes remain insufficient for the personalized combination therapies based on multi-omics and artificial intelligence discussed by the authors. Further validation is needed to close the gap between mechanistic potential and actual patient benefit.
This article is based on the provided abstract and publicly available full-text excerpts from the Molecular Biomedicine review.
Therapeutic resistance remains a major cause of treatment failure and disease recurrence across cancer types, considerably limiting the long-term efficacy of chemotherapies, targeted therapies, and immunotherapies. Growing evidence indicates that resistance cannot be fully explained by static genetic alterations but rather arises from dynamic and reversible adaptive processes. Epigenetic regulation governs transcriptional plasticity, cellular state transitions, and tumor heterogeneity under therapeutic stress. Alterations in DNA methylation, histone modifications, chromatin accessibility, and non-coding RNA networks enable cancer cells to silence tumor suppressor programs, activate compensatory survival pathways, acquire stem cell-like drug-tolerant persister states, and remodel the tumor immune microenvironment. These mechanisms often act in a coordinated manner to form a dynamic regulatory system that supports adaptive resistance. However, current studies have frequently focused on individual epigenetic regulators and have lacked an integrated framework to explain how epigenetic plasticity collectively drives therapeutic resistance. In this review, we deconstruct cancer therapy resistance using the conceptual framework of the "epigenetic landscape." We summarize the molecular functions and crosstalk among the major epigenetic layers and describe how this integrated network sustains key resistance-associated phenotypes. We also discuss emerging therapeutic strategies that target epigenetic plasticity, including epigenetic drugs, targeted protein degradation, epigenetic editing, and rational combination therapies. Overall, this review provides a systematic framework for understanding epigenetically mediated therapy resistance and highlights epigenetic plasticity as a therapeutic vulnerability for developing durable cancer treatments.
The practical value of this review lies in outlining a research direction that examines resistance both as a problem of specific genetic mutations and as a problem of cell states that change during treatment. For example, a clinical study of combination therapy could track changes in tumor methylation and gene expression before and after treatment while assessing signals of restored drug sensitivity alongside toxicity. This information could help test which regulatory pathways to target in which patients and whether drugs should be administered simultaneously or sequentially. This is a research application scenario based on the review’s discussion. It does not mean that fundamental suppression of resistance, prevention of relapse, or improved survival has been demonstrated; clinical validation by cancer type is needed to support actual treatment choices.