Deciphering the precise survival strategies of cancer cells: RNA epitranscriptomics guides immune evasion and drug resistance mechanisms
Background: Cancer biology beyond gene expression and the epitranscriptome
Cancer research has long focused on DNA mutations and genomic instability. With the advancement of genomic analysis techniques, numerous major cancer genes have been identified. However, even among patients with the same gene mutations, there are limitations in terms of treatment response and immune evasion. The epitranscriptome, which finely regulates gene expression at the RNA level without sequence changes, is emerging as a key to unlocking these clues.
Chemical modifications to RNA after transcription control the stability and translational efficiency of transcripts within cells, as well as the formation of secondary structures, in real-time. In the past, molecular biology has focused on technically mapping individual RNA modifications. However, there has been a lack of comprehensive research that systematically establishes the functional link between the complex immune microenvironment and drug resistance within cancer tumors. It has become an urgent task to elucidate how cancer cells reprogram the epitranscriptomic network for survival.
Key Findings: Interaction of six RNA modification networks and tumor immune microenvironment
In this study, the researchers conducted an in-depth analysis of the integrated regulatory mechanisms of six major RNA modifications, including N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), 7-methylguanosine (m7G), pseudouridine (Ψ), and adenosine-to-inosine (A-to-I) editing. They demonstrated that the writer, reader, and eraser enzyme groups, which cause RNA modifications, manipulate transcript stability and translational efficiency, thereby inducing tissue-specific tumor evolution.
In particular, the points at which epitranscriptomic regulatory factors intersect with the tumor immune microenvironment (TIME) are clearly identified. Cancer cells precisely regulate the levels of m6A and m5C modifications to block the major histocompatibility complex (MHC)-based antigen presentation process. At the same time, they increase the mRNA stability of immune checkpoint molecules such as PD-L1, activating an immune evasion mechanism that avoids immune cell attacks.
Furthermore, epitranscriptomic reprogramming acts as a key variable that determines drug resistance. Cancer cells exposed to chemotherapeutic agents and radiation therapy activate A-to-I editing enzymes or Ψ synthase, significantly promoting the translation of transcripts related to DNA damage repair. This leads to the acquisition of resistance to targeted anticancer drugs and immune checkpoint inhibitors (ICI), which is a major factor that reduces the efficacy of existing anticancer treatments.
Significance and Prospects: Development of RNA modification enzyme-targeted anticancer drugs and expansion of precision medicine
This study goes beyond simply observing RNA modifications and expands the molecular epitranscriptomic phenomenon into a functional framework for cancer biology. It suggests that small molecule therapeutic agents targeting m6A eraser enzymes such as FTO or ALKBH5, or the m6A writer METTL3/METTL14 complex, may emerge as next-generation anticancer strategies. The use of epitranscriptomic biomarkers can enable the establishment of precision medicine by predicting drug resistance and immunotherapy response rates on a patient-by-patient basis.
However, there are also practical challenges for clinical application. The difference in RNA modification between normal cells and cancer cells is very small, and systemic side effects may be caused if precise delivery technology is not used. In order to improve the completeness of anticancer treatment, it is necessary to develop a test platform that measures epitranscriptomic heterogeneity between cells in patient tumors at the single-cell level in real-time.
RNA modifications, such as N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), 7-methylguanosine (m7G), pseudouridine (Ψ), and adenosine-to-inosine (A-to-I) editing, constitute a dynamic epitranscriptomic network that profoundly regulates RNA metabolism and gene expression. Their dysregulation is increasingly recognized as a hallmark of cancer. This review critically synthesizes the multifaceted roles of RNA modifications to bridge the gap between descriptive epitranscriptomic mapping and functional tumor biology. We systematically evaluate how writers, readers, and erasers dictate transcript stability and translation efficiency, driving tissue-specific tumor evolution across diverse malignancies. Crucially, we explore the intersection of RNA modifications and the tumor immune microenvironment, detailing their mechanisms in orchestrating immune evasion, altering antigen presentation, and regulating immune checkpoints. Furthermore, we examine how epitranscriptomic reprogramming dictates cellular responses to chemotherapy, radiotherapy, targeted treatments, and immunotherapy. By comprehensively analyzing these mechanisms, this review aims to facilitate the translation of epitranscriptomic findings into clinical applications, laying a theoretical foundation for targeted anti-tumor strategies.
This study presents three specific application scenarios for the cancer diagnosis and drug development industries. First, it is the development of a companion diagnostic biomarker for immune checkpoint inhibitors. By measuring m6A and m5C modification patterns in a patient's tumor tissue or liquid biopsy sample, PD-1/PD-L1 inhibitor responsiveness can be accurately classified. Second, it is the discovery of new drug candidates to overcome targeted drug resistance. By co-administering a new generation of synthetic therapeutic agents that inhibit RNA editing enzymes (such as ADAR1) activated during the administration of existing anticancer drugs, drug resistance can be overcome. Third, it is the advanced mRNA vaccine and therapeutic platform. By incorporating pseudouridine modification technology into the design of cancer vaccines, the stability of RNA in vivo can be maximized, while unnecessary innate immune responses can be reduced, thereby improving the therapeutic efficacy of anticancer vaccines.