Multidrug resistance (MDR) is a central cause of chemotherapy failure and tumor recurrence and metastasis, and its mechanism involves enhanced drug efflux, target mutation, upregulation of DNA repair and remodeling of the tumor microenvironment. ABC transporter protein (P-gp, MRP, and BCRP)-mediated efflux of drugs is the most intensively researched aspect of the study, but the first three generations of small-molecule reversal agents were stopped in the clinic because of toxicity or pharmacokinetic defects. Natural products are considered as the fourth generation of MDR reversal agents due to their structural diversity, multi-targeting and low toxicity. In this paper, we systematically summarize the inhibitory activities of monoterpenes, sesquiterpenes, diterpenes and triterpenes against ABC transporter proteins in in vitro and in vivo models and focus on the new mechanism of reversing drug resistance by blocking efflux pumps, modulating signaling pathways such as PI3K-AKT, Nrf2, NF-κB and remodeling the tumor microenvironment. For example, Terpenoids possess irreplaceable core advantages over traditional multidrug resistance (MDR) reversers: Compared with the first three generations of synthetic reversers, natural/semisynthetic terpenoids integrate low toxicity (mostly derived from edible medicinal plants, half-maximal inhibitory concentration IC₅₀ > 50 μM), high target specificity (e.g., oleanolic acid specifically inhibits the ATP-binding cassette (ABC) transporter subtype ABCC1 without cross-reactivity with ABCB1), and multi-mechanistic synergistic effects (e.g., β-caryophyllene simultaneously mediates the dual effects of “ABCB1 efflux inhibition + apoptotic pathway activation”). These unique characteristics enable terpenoids to effectively circumvent key limitations of traditional synthetic reversers, such as high toxicity and severe drug–drug interactions. Among them, lupane-type derivative BBA and euphane-type sooneuphanone D (triterpenoids), as well as dihydro-β-agarofuran-type compounds and sesquiterpene lactone Conferone (sesquiterpenoids), have emerged as the core lead compounds with the greatest translational potential in current MDR reverser research, attributed to their potent in vitro and in vivo MDR reversal activity, low toxicity, and excellent druggable modifiability. At the same time, we point out bottlenecks, such as low bioavailability, insufficient in vivo evidence, and unclear structure–activity relationship and put forward a proposal to address these bottlenecks. At the same time, the bottlenecks of low bioavailability, insufficient vivo evidence and unclear structure–activity relationship have been pointed out, and future research directions such as nano-delivery, structural optimization and combination strategies have been proposed to provide theoretical foundations and potential practical pathways for the clinical translation research of terpenoid compounds, whose clinical application still requires further in vivo validation and translational research support.

The zinc finger protein with KRAB and SCAN domains 3 (ZKSCAN3) has emerged as a critical regulator of diverse cellular processes, including autophagy, cell cycle progression, and tumorigenesis. Structurally, ZKSCAN3 is characterized by its conserved DNA-binding zinc finger motifs, a SCAN domain mediating protein–protein interaction, and a KRAB repression domain implicated in transcriptional regulation. Post-translational modifications, such as phosphorylation and ubiquitination, dynamically modulate its subcellular localization and activity, enabling context-dependent functional plasticity. Functionally, ZKSCAN3 acts as a master switch in autophagy by repressing the transcription of autophagy-related genes under nutrient-replete conditions, while its nuclear-cytoplasmic shuttling under stress conditions links metabolic reprogramming to cellular survival. Emerging evidence also underscores its paradoxical roles in cancer: it suppresses tumor initiation by maintaining genomic stability yet promotes metastasis through epithelial–mesenchymal transition induction. Furthermore, epigenetic mechanisms, including promoter methylation and non-coding RNA regulation, fine-tune ZKSCAN3 expression, contributing to tissue-specific outcomes. Despite these insights, gaps remain in understanding the structural determinants governing its interaction with chromatin-remodeling complexes and the therapeutic potential of targeting ZKSCAN3 in diseases. Future investigations should prioritize integrating multi-omics approaches to unravel context-specific regulatory networks and explore small-molecule modulators for translational applications. This comprehensive analysis provides a framework for advancing our mechanistic understanding of ZKSCAN3 and its implications in human health and disease. This review synthesizes recent advances in elucidating the regulatory networks and functional complexity of ZKSCAN3, highlighting its dual roles in physiological and pathological contexts.

Background: Natural products with unique mechanisms remain of great interest because targeted cancer therapies frequently fail due to toxicity or resistance. Cardiac glycosides have demonstrated antitumor activity, but whether their effects involve microRNA regulation remains largely unexplored. This study investigates whether ouabain derived from Strophanthus gratus (Wall. & Hook. ex Benth.) Baill. (SGO) exerts its antitumor effects through miR-145-5p, a known tumor suppressor, using both colorectal and breast cancer models. Methods: We performed transcriptomic profiling in HCT116 colorectal cancer cells treated with SGO, followed by in vitro assays—including cell viability, caspase 3/7 activity, flow cytometry, and colony formation—in HCT116 and MCF-7 breast cancer cells. In vivo efficacy was evaluated using HCT116 xenograft models in BALB/c-nu/nu mice. miR-145-5p gain- and loss-of-function approaches were employed to determine its functional requirement. Results: SGO dose-dependently suppressed proliferation, induced apoptosis, and inhibited colony formation in both colorectal (HCT116) and breast (MCF-7) cancer cells, and significantly upregulated miR-145-5p levels in both cell types. Transcriptomic analysis identified miR-145-5p as a highly differentially expressed miRNA. In HCT116 xenograft models, SGO inhibited tumor growth by approximately 60% and elevated intratumoral miR-145-5p levels. Importantly, inhibition of miR-145-5p significantly attenuated these effects both in vitro and in vivo, establishing that the antitumor activity of SGO depends on the upregulation/activation of miR-145-5p in both cancer types. Conclusions: We have found that SGO inhibits colorectal and breast cancer growth through a miR-145-5p-dependent mechanism, revealing a previously unrecognized regulatory axis for cardiac glycosides. These findings position SGO as a promising candidate for further preclinical studies and suggest that pharmacologic re-expression of miR-145-5p may represent a viable therapeutic strategy in targeted therapy.

Non-coding RNAs (ncRNAs) regulate gene expression at multiple levels in cancer, yet their functional plasticity and the slow pace of clinical translation remain incompletely explained. This review is organized around a unifying theme: ncRNAs act as integrative nodes connecting the epigenetic, transcriptional, signaling, and metabolic regulatory layers. Building on the established signal, sponge, scaffold, and guide archetypes of long non-coding RNA function, we extend this schema into a 4S+G model that adds a splice-regulatory archetype and embeds all five modes in a three-axis taxonomy spanning structural topology, subcellular localization, and molecular mode of operation, thereby capturing context-dependent functions that binary structural categories cannot accommodate. We dissect chromatin remodeling dynamics, evaluate the competing endogenous RNA hypothesis against stoichiometric evidence, and trace metabolic–epigenetic feedback circuits that stabilize malignant states. We then critically appraise the clinical record of ncRNA therapeutics, from the termination of MRX34 to the modest efficacy of subsequent candidates, and analyze the delivery, immunogenicity, and biomarker barriers that distinguish oncology from other indications for RNA drugs. Emerging solutions, including ligand-directed extrahepatic delivery, spatial transcriptomics, and deep learning-based target prediction, are assessed against these bottlenecks. The 4S+G framework links mechanistic understanding to a realistic roadmap for developing ncRNA-targeted cancer therapeutics with favorable risk–benefit profiles.

Non-coding RNAs (ncRNAs) are the biggest class of regulatory molecules in the human genome, which constitute ~98% of total transcripts, and were once considered as “transcriptional noise”. This review will focus on the newly identified functions of non-coding RNAs (ncRNAs) in cancer biology and therapeutic innovations. We review the existing knowledge on microRNAs, long non-coding RNAs, and circular RNAs in the context of their different experimental and computational studies, and we highlight their mechanisms of action in cancer hallmarks such as proliferation and resistance to apoptosis, metastasis, and metabolic reprogramming. We evaluate the translational landscape of ncRNA-based therapeutics by examining clinical trials in progress and completed, delivery methods, and emerging technologies. This review aims to separate fact from fiction and offer a balanced view on the facts, which will help guide future research and clinical development in the field of ncRNA oncology.