Cervical adenocarcinoma exhibits intrinsic resistance to radiotherapy, yet the molecular mechanisms underlying this phenotype remain poorly understood. We integrated transcriptomic analyses of TCGA and an independent RNA-sequencing cohort to identify dysregulated long noncoding RNAs (lncRNAs) in cervical adenocarcinoma. Multiple functional studies, including clonogenic survival, proliferation, apoptosis, glycolytic flux, xenograft irradiation, patient-derived organoids, and clinical validation, were combined with RNA pull-down, RNA immunoprecipitation, chromatin immunoprecipitation, immunofluorescence, and rescue experiments to define the underlying molecular mechanism. CYP4A22-AS1 emerged as a consistently upregulated lncRNA in cervical adenocarcinoma and was associated with aggressive clinicopathological features and poor clinical outcome. Mechanistically, CYP4A22-AS1 directly interacted with the RNA- and DNA-binding protein YBX1, promoted its nuclear accumulation, and enhanced YBX1 recruitment to the glycolytic enzyme PGK1 promoter, resulting in transcriptional activation of PGK1. Disruption of the CYP4A22-AS1–YBX1–PGK1 axis suppressed glycolytic activity, impaired DNA damage repair, increased radiation-induced apoptosis, and markedly enhanced radiosensitivity in vitro. Consistent with these findings, CYP4A22-AS1 promoted resistance to irradiation in xenograft and patient-derived organoid models. Clinically, elevated CYP4A22-AS1 and PGK1 expression correlated with unfavorable prognosis. Our findings identify a previously unrecognized lncRNA-dependent mechanism in which CYP4A22-AS1 promotes YBX1 nuclear accumulation and PGK1 transactivation, thereby coupling metabolic adaptation to DNA damage repair and intrinsic radioresistance in cervical adenocarcinoma. This pathway represents a potential therapeutic vulnerability for improving radiotherapy response.
Liquid-liquid phase separation (LLPS) is a physicochemical process through which biomolecules assemble into membraneless condensates via weak, multivalent interactions. LLPS has emerged as a central biological principle that helps explain intracellular spatiotemporal compartmentalization, signal transduction, and stress responses. Dysregulated LLPS contributes to tumor initiation, progression, immune evasion, and treatment resistance; however, its cell-type-specific functions and relevance to radiotherapy and immunotherapy remain incompletely integrated. In this review, we critically synthesize recent mechanistic and translational advances linking LLPS to cancer radiotherapy and immunotherapy. Condensates may either support therapeutic resistance and immune evasion or enhance radiosensitivity and antitumor immunity, depending on their molecular composition, subcellular localization, cell type, and treatment context. We examine how condensate regulation connects radiation-induced DNA damage repair with innate immune activation and evaluate emerging therapeutic strategies that target disease-associated condensates. We also assess LLPS-associated abnormal condensates as candidate biomarkers for prognosis and prediction of tumor response to radiotherapy and immunotherapy. Tissue-specific LLPS regulation across tumor types, dynamic condensate remodeling under therapeutic stress, and rational strategies combining phase-separation modulation with immune-checkpoint inhibitors and radiotherapy require further investigation. Integrating multi-omics data with artificial intelligence-based algorithms may help construct systematic LLPS-related therapeutic-event maps and predictive models, thereby prioritizing experimentally testable hypotheses for personalized cancer management. With rigorous mechanistic validation and prospective clinical evaluation, selective modulation of disease-associated condensates may enhance radiosensitivity and strengthen antitumor immunity.
Alternative splicing (AS) expands transcriptomic and proteomic diversity and is increasingly implicated in colorectal cancer (CRC) progression, yet the functional relevance of individual AS isoforms and the splicing regulators directing their generation remain poorly understood. RNA sequencing was conducted on five paired CRC tumor and adjacent normal tissue samples to profile the AS landscape and identify differentially spliced transcripts. Candidate isoform expression was verified by RT-PCR, quantitative RT-PCR, and immunoblotting. CALD1 isoform functions were assessed by gain-/loss-of-function assays in vitro and in vivo. To dissect the upstream splicing control and downstream protein interactions of CALD1S, we employed RNA immunoprecipitation, minigene splicing assays, RNA pull-down, co-immunoprecipitation, and mass spectrometry-based proteomics. Clinical relevance was evaluated using public datasets and independent CRC patient cohorts. Widespread AS aberrations were observed in CRC, with 1,048 significantly altered events identified. Among these, a short CALD1 isoform lacking exons 3b and 4 (hereafter termed CALD1S) was preferentially expressed in tumor tissues. Elevated CALD1S expression significantly correlated with advanced tumor stage, lymph node metastasis, and poorer patient survival. Functional assays demonstrated that CALD1S promoted CRC cell migration and invasion in vitro and enhanced liver metastatic dissemination in vivo, while exerting negligible impact on cell proliferation. Mechanistically, the splicing factor hnRNPA1 bound CALD1 pre-mRNA and promoted skipping of exons 3b and 4, thereby augmenting CALD1S biogenesis. Restoring CALD1S expression partially rescued the impaired migratory and invasive phenotypes induced by hnRNPA1 depletion. Furthermore, MYH9 was identified as a CALD1S-interacting protein and its knockdown attenuated CALD1S-driven cell migration. Clinically, CALD1 and MYH9 protein levels exhibited a strong positive correlation in lymph node-positive CRC tumors, and a higher combined CALD1/MYH9 expression was associated with unfavorable prognosis. Our study delineates an hnRNPA1-CALD1S-MYH9 regulatory axis that couples aberrant AS to CRC metastatic progression. These findings support CALD1S as a potential prognostic biomarker for disease progression in CRC.
Despite advances in targeted therapy, effective treatment of KRAS-mutant colorectal cancer (CRC) remains challenging. Although circular RNAs (circRNAs) have emerged as important regulators of tumorigenesis, the functional significance of circRNA-encoded micropeptides in KRAS-mutant CRC remains poorly understood. Integrative transcriptomic profiling was used to identify dysregulated circRNAs in KRAS-mutant CRC. The coding potential of circRAB6A was evaluated using bioinformatic prediction, internal ribosome entry site (IRES) reporter assays, and mass spectrometry. The functional effects of circRAB6A and its encoded micropeptide were assessed using in vitro assays and orthotopic and patient-derived xenograft (PDX) models. Mechanistic studies combined RNA sequencing, co-immunoprecipitation, bio-layer interferometry, and molecular dynamics simulations. We identify circRAB6A as a highly expressed circRNA in KRAS-mutant CRC, with elevated circRAB6A abundance associated with poor clinical outcomes. circRAB6A harbors a short open reading frame and encodes a previously uncharacterized micropeptide, designated KAPEP. KAPEP promotes CRC cell proliferation, migration, and invasion in vitro and accelerates tumor growth in vivo. Mechanistically, KAPEP directly binds PTPN6 and inhibits its phosphatase activity, thereby relieving PTPN6-mediated restraint on JAK-STAT signaling and sustaining pathway activation. Our findings identify KAPEP as a functional circRNA-encoded micropeptide that promotes KRAS-mutant CRC progression through the PTPN6/JAK-STAT axis. These results highlight the KAPEP/PTPN6 interaction as a potential therapeutic vulnerability in KRAS-mutant CRC.
Immune checkpoint blockade directed against the programmed cell death protein 1 (PD-1) receptor and its ligand PD-L1 has markedly transformed cancer therapy, producing sustained clinical benefit and prolonged survival in selected patient populations across multiple tumor types. However, clinical responses remain highly heterogeneous, largely limited by low overall response rates, the development of both intrinsic and acquired resistance, and immune-related toxicities that restrict the durability of single-agent treatment. In this article, we systematically examine the PD-1/PD-L1 axis from a mechanistic perspective, spanning its roles in tumor initiation, disease progression, metastatic spread, and immune escape. We detail how PD-1/PD-L1 axis drives T cell exhaustion, impairs antigen presentation, reshapes the immunosuppressive tumor microenvironment, and promotes epithelial–mesenchymal transition (EMT), thereby enabling immune escape throughout tumor evolution. We further catalog recent innovations in PD-1/PD-L1-targeted therapeutics, spanning monoclonal antibodies, bispecific molecules, Fc-optimized biologics, and novel synthetic modalities—including RNA interference, CRISPR-based gene editing, antisense oligonucleotides, and mRNA platforms. In addition, we evaluate emerging small-molecule inhibitors designed to directly disrupt PD-1/PD-L1 engagement, modulate checkpoint expression transcriptionally or post-translationally, and reprogram oncogenic, metabolic, and epigenetic circuits to circumvent resistance. A dedicated focus is placed on deciphering adaptive and intrinsic resistance mechanisms, such as PD-L1 re-induction, T cell dysfunction, deficits in antigen presentation, and compensatory upregulation of alternative immune checkpoints (e.g., LAG-3, TIM-3, TIGIT). We also examine rationale-driven combination approaches that integrate checkpoint inhibitors with targeted agents, chemotherapy, metabolic modulators, and epigenetic drugs to amplify antitumor immunity. Taken together, this review proposes an integrated framework for understanding the diverse roles of the PD-1/PD-L1 axis in tumor–immune interactions and offers strategic guidance for the development of next-generation checkpoint inhibitors and precision immunotherapy approaches.
