Crosstalk between microRNA and oxidative stress in ovarian cancer: diagnosis, pathogenesis and therapeutic resistance.

Introduction
Ovarian cancer (OC) remains the most lethal form of gynaecological cancer globally, a mortality rate largely attributable to late-stage diagnosis, frequent relapses, and the evolution of resistance to standard platinum-based therapies [1], [2]. Among the most significant drivers of OC advancement is oxidative stress (OS), perceived as an excess of reactive oxygen species (ROS) relative to the cell’s antioxidant capacity [3]. ROS serve vital roles in transducing physiological signals,however, unchecked accumulation provokes selective damage to nucleic acids, proteins, and membrane lipids, in turn fuelling genomic instability, epithelial-to-mesenchymal transition (EMT), angiogenic sprouting, and diminished sensitivity to chemotherapy [4]. Intriguingly, augmented ROS concentrations can simultaneously trigger apoptotic pathways and foster resistance to cytotoxic agents, underscoring a bifunctional and microenvironmentally contingent redox milieu in OC [5]. As a salient illustration, Nrf2 pathway upregulation enhances the cell’s antioxidant arsenal yet also correlates with a diminished response to chemotherapy [6]. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene regulation. Their dysregulation in OC has been shown to affect cell proliferation, metastasis, and treatment response [7]. ROS modulates miRNA biogenesis via epigenetic changes, while some miRNAs, in turn, regulate ROS production, forming complex redox-sensitive feedback loops that influence tumour progression [8]. Key examples include the miR-200 family (which regulates EMT), miR-29b (targets DNA repair via SIRT1), miR-484 (influences mitochondrial function), and miR-21 (promotes PI3K/AKT signalling) [9]. Their presence in serum, exosomes, and tumour tissues makes miRNAs attractive candidates for diagnostic, prognostic, and therapeutic monitoring purposes [10]. However, inter-patient variability and the absence of standardized protocols for normalization and quantification remain major barriers to clinical translation [11].Therapeutically, emerging strategies aim to restore or inhibit specific miRNAs using synthetic mimics or inhibitors (antagomiRs) to re-establish tumor suppressor function or attenuate oncogenic pathways. AntagomiRs are synthetically designed molecules are used to neutralize microRNA function in cells for desired responses [12]. Advances in nanotechnology offer promise for improved targeted delivery, although challenges related to bioavailability, immunogenicity, and pharmacokinetics persist [13].

The role of oxidative stress in ovarian cancer
Ovarian cancer (OC) continues to rank as the most fatal gynecologic cancer primarily because most cases are diagnosed at an advanced stage, accompanied by substantial recurrence rates and enduring resistance to platinum-based chemotherapeutics [14]. Oxidative stress (OS), defined as the disturbance of redox equilibrium that favors reactive oxygen species (ROS) over the antioxidant defense system, has emerged as a critical driver of these clinical aggressiveness features [12]. Elevated levels of OS biomarkers, including nitric oxide (NO) and malondialdehyde (MDA), correlate with later-stage disease and unfavorable outcomes in patients with OC [15]. Although ROS are intrinsic byproducts of fundamental energy pathways, including mitochondrial oxidative phosphorylation and NADPH oxidase activity, their pathological overproduction in OC cells is augmented by metabolic rewiring and the oxidative challenge posed by genotoxic interventions such as chemotherapy and radiotherapy [3], [16]. Mitochondrial impairment serves as a predominant origin of reactive oxygen species in ovarian cancer cells, with superoxide production primarily arising from localized electron transport chain “leaks” [17]. Concurrently, the nicotinamide adenine dinucleotide phosphate oxidase family—most notably NOX4 and NOX5—further contributes to ROS buildup, triggered by pro-tumor and inflammatory signals [18]. In addition, the hypoxic microenvironment characteristic of the ovarian cancer tumor microenvironment destabilizes oxidative phosphorylation and exacerbates ROS generation [19].

Impact of ROS on tumor biology
Reactive oxygen species (ROS) induce oxidative modifications in DNA, lipids, and proteins, leading to compromised membrane integrity and disruption of intracellular signaling pathways [20]. These molecular perturbations promote neoplastic growth, foster genomic instability, and contribute to resistance against apoptosis and therapeutic interventions in ovarian cancer [17]. Elevated ROS levels in ovarian carcinoma further stimulate angiogenesis, drive metabolic reprogramming, and facilitate epithelial-to-mesenchymal transition (EMT), a critical process for tumor invasion and metastasis [21]. ROS influence EMT by activating key transcriptional regulators and inducing epigenetic changes, including alterations in DNA methylation patterns [22]. The interplay between ROS and these cellular processes underscores their central role in ovarian cancer pathogenesis and highlights the importance of targeting oxidative stress pathways for improved diagnostic and therapeutic strategies [23].The reciprocal crosstalk between ROS and microRNAs in these processes is schematically depicted in Fig. 1.

ROS in therapy resistance
Reactive oxygen species (ROS) perform opposing functions in oncologic pharmacotherapy.Agents like cisplatin exploit oxidative DNA lesions to trigger apoptosis; however, excessive ROS can concurrently activate survival pathways, culminating in therapeutic resistance [24]. Ovarian cancer (OC) cells respond to oxidative stress by upregulating their antioxidant machinery, notably glutathione peroxidase and superoxide dismutase (SOD), thereby fortifying their survival under cytotoxic stress [25], [20]). Concurrent activation of transcription factors, primarily nuclear factor-κB (NF-κB) and nuclear factor-erythroid-2-related factor 2 (NRF2), elicits transcriptional programs that promote the expression of anti-apoptotic proteins, enhance drug efflux, and preserve cellular integrity [26, 27]). NRF2 plays a central role in platinum resistance by orchestrating drug biotransformation, potentiating efflux pumps, and maintaining redox equilibrium [6]. Its aberrant hyperactivation not only accelerates the stem-like phenotype of tumor-initiating cells but also fosters disease recurrence. Targeted suppression of NRF2—using small molecules like ML385—augmented with selective inhibitors of glutathione peroxidase 4 (GPX4), effectively precipitates ferroptotic cell death by destabilizing the redox milieu. Additionally, accumulation of p62 can activate the Keap1-NRF2 axis, further exacerbating therapeutic resistance [28].

Oxidative stress and immune evasion
Oxidative stress contributes to immune evasion in OC by remodelling the tumour microenvironment (TME) into an immunosuppressive niche. ROS and reactive nitrogen species (RNS) directly impair antitumor immune function and promote chronic inflammation [29], [30]. Persistent OS fosters the polarization of tumor-associated macrophages (TAMs) toward an M2-like phenotype, characterized by secretion of IL-10, TGF-β, and expression of PD-L1 and CTLA-4, leading to the suppression of T-cell activation and promoting immune escape [31]. ROS also stimulate the recruitment of immunosuppressive T regulatory (Treg) cells and myeloid-derived suppressor cells (MDSCs), further dampening cytotoxic responses [3]. Of particular interest, OS facilitates the release of exosomes carrying redox-sensitive miRNAs. These exosomal miRNAs can reprogram recipient immune cells, promoting M2 polarization and impairing CD8⁺ T cell cytotoxicity [32]. This emerging exosome–miRNA axis represents a novel immune evasion mechanism and a potential target for therapeutic intervention.

MicroRNAs in relation to ovarian cancer and the regulation of oxidative stress
Ovarian cancer (OC) development is closely linked to microRNA (miRNA) deregulation and its reciprocal engagement with oxidative stress (OS)—the state arising when reactive oxygen species (ROS) overwhelm cellular antioxidant mechanisms [33], [34]. Such disrupted molecular interplay disturbs intracellular redox homeostasis, fosters malignant evolution, and is implicated in acquired resistance to standard treatments. Dissecting these coordinated alterations may reveal redox-sensitive pathways amenable to novel therapeutic intervention and advance the identification of informative biomarkers [35].
Figure 2 ROS generation and effects in ovarian cancer.

Impact of miRNAs on the oxidative stress response
Small non-coding RNAs, particularly miRNAs, exert critical influence over redox balance by fine-tuning intracellular ROS production, orchestrating redox-sensitive signaling cascades, and preserving mitochondrial architecture [36]. MiR-29b, designated a tumor suppressor, inhibits the NAD+ -dependent deacetylase SIRT1, a key regulator of DNA integrity and ROS detoxification. Its loss of expression in ovarian cancer (OC) results in mitochondrial membrane potential collapse, accumulation of oxidative lesions, and accelerated apoptotic signaling [37]. In contrast, enforced SIRT1 expression fosters chemoresistance via augmented antioxidant defenses [38]. Therapies aimed at restoring miR-29b could, therefore, re-engage oxidative stress-induced cytotoxicity and potentiate the efficacy of platinum-based regimens. Components of the miR-200 family, including miR-141 and miR-200a, directly repress MAPK14 (also designated p38α), a redox-sensitive mitogen-activated protein kinase that integrates stress, inflammatory, and DNA damage response signals [39]. Inhibition of this kinase by miR-200 gfamily members attenuates pro-oxidant signaling and DNA repair, underscoring their dual role in mitochondrial protection and preservation of genomic integrity. miR-141-3p promotes M2 macrophage polarization via Keap1-Nrf2 signaling, while miR-200a suppresses Keratin-19 (KRT19), enhancing NRF2-driven antioxidant responses [40]. MiR-484 represses SESN2, a redox-sensitive autophagy mediator, thereby exacerbating mitochondrial dysfunction, ROS accumulation, and apoptosis [41, 42]. In contrast, miR-361-5p mitigates mitochondrial ROS and preserves mitochondrial health [43].

Oxidative stress as a regulator of miRNA expression
Oxidative stress is not only regulated by microRNAs (miRNAs) but also modulates their expression and processing, establishing bidirectional feedback loops that critically influence ovarian cancer behavior. Below is a comprehensive table summarizing 20 miRNAs relevant to ovarian cancer, including their targets, functions, and clinical relevance (Table 1).
Oxidative stress also activates transcription factors such as NF-κB, p53, and HIF-1α, which influence miRNA transcription [56]. ROS can modulate miRNA-processing enzymes, including Drosha and Dicer [56, 57]. Acute oxidative stimuli (e.g., H2O2) increase miR-29b, whereas chronic exposure (e.g., smoking) leads to its downregulation, indicating context-specific miRNA responses [1]. Persistent OS may also repress SESN2 through miR-484, amplifying mitochondrial injury. Age-related Dicer downregulation leads to impaired miRNA maturation and contributes to redox imbalance and chemoresistance in OC.

Clinical implications and therapeutic potential
Deciphering the miRNA–ROS axis may inform redox-responsive therapeutic strategies and precision oncology approaches. Key pathways involved include hypoxia signaling, apoptosis, and the DNA damage response.MiR-21 and miR-214 suppress PTEN, activating the PI3K/AKT/mTOR pathway, thereby enhancing platinum resistance [58, 59]. MiR- 497 restoration reverses these effects and improves therapy sensitivity. Circulating and exosomal miRNAs—including miR-21-3p, miR-891-5p, miR-320b, and miR-320d—show potential as biomarkers for recurrence risk and therapy resistance [3] in development to modulate oxidative balance and improve drug response. ROS-responsive delivery systems allow localized activation of such therapeutics in the tumor microenvironment [60]. Emerging technologies, including spatial transcriptomics, high-throughput miRNA editing, and redox imaging, will refine patient stratification and guide miRNA-based combination therapies [61].

The impact of oxidative stress on microrna expression in ovarian cancer
Oxidative stress (OS), a hallmark of ovarian cancer (OC), disrupts redox balance and contributes to key cancer hallmarks including apoptosis, angiogenesis, epithelial–mesenchymal transition (EMT), therapy resistance, and radiotherapy response [62]. MicroRNAs (miRNAs), as redox-sensitive post-transcriptional regulators, modulate gene networks that govern OC cell fate and therapeutic outcomes. This section outlines how oxidative stress and miRNAs interact to influence OC progression [63].

miRNAs in the regulation of apoptosis and cell cycle
Reactive oxygen species (ROS) initiate apoptosis in OC via DNA damage and downstream signaling cascades. For example, 1C-chalcone derivatives trigger apoptosis in both cisplatin-sensitive and -resistant OC cells through ROS accumulation and activation of p21 and NF-κB pathways [64]. DCTPP1 knockdown increases ROS and apoptosis, whereas its overexpression promotes cisplatin resistance [54, 55]. ROS-induced inhibition of the PI3K/AKT pathway also activates mitochondrial apoptosis via PUMA [18].
Figure 3 functional roles of miRNAs in tumor biology.
MiRNAs modulate apoptotic balance. The miR-15/16 cluster suppresses anti-apoptotic genes such as BCL2 and Cyclin D1, sensitizing cells to oxidative injury.MiR-29b targets SIRT1, a mitochondrial deacetylase, impairing antioxidant defenses and promoting apoptosis [19]. Restoring miR-29b may reverse therapy resistance in oxidative-stress-adapted tumors.

miRNAs and angiogenesis
Tumor angiogenesis in OC is driven by hypoxia-mediated ROS, which activates HIF-1α and VEGF signaling. MiR-155-5p responds to oxidative stimuli and suppresses HIF-1α, regulating endothelial differentiation and angiogenesis [12]. MiR-200b inhibits VEGF-A and ZEB1, limiting neovascularization [65]. Other angiogenesis-related miRNAs include miR-204-5p, which represses THBS1, a known angiogenesis inhibitor [66]. MiR-367 targets LPA1, reducing vessel formation, while miR-133a-5p enhances vascularization via the TRIM59/VEGF axis [67]. MiR-6086 inhibits the OC2/VEGFA/EGFL6 pathway, making it a potential anti-angiogenic target [68].

miRNAs in epithelial–mesenchymal transition (EMT)
ROS promote EMT through activation of NF-κB, Snail, and β-catenin signaling. MiR-200c reinforces the epithelial phenotype by upregulating E-cadherin and suppressing ZEB1/ZEB2. Loss of miR-200c induces mesenchymal traits, metastasis, and chemoresistance [65]. ROS downregulate miR-200c, thus promoting EMT and aggressive tumor behavior [69]. These miRNAs act as redox-controlled switches governing plasticity [70].

miRNAs and chemoresistance
Redox dysregulation contributes to platinum resistance via antioxidant pathway upregulation, enhanced DNA repair, and altered drug metabolism. MiR-106b-5p targets OLR1, and its suppression correlates with cisplatin resistance [71]. MiR-21 downregulates PTEN, thereby activating PI3K/AKT signaling and promoting resistance [72]. Though not a redox controller, miR-21 is ROS-inducible, creating a feedback loop that amplifies survival signaling. Targeting miR-21 restores PTEN and enhances treatment efficacy [68]. Exosomal miRNAs such as miR-21-3p, miR-891-5p, and miR-320d, derived from small extracellular vesicles (sEVs), regulate glycolysis, ABC transporters, and DNA repair mechanisms, thus fostering resistance [3]. MiR-152-3p reverses paclitaxel resistance by modulating the PTEN/ATG4D-autophagy pathway [71]. MiR-450b-5p enhances carboplatin resistance via ACTB and the PI3K/AKT axis [73].

miRNAs and radioresistance
Although ionizing radiation kills cancer cells through ROS induction, many OC subtypes exhibit radioresistance. MiR-34a enhances radiosensitivity by targeting BCL2 and SIRT1 [74]. MiR-17-5p suppresses MnSOD, increasing ROS and sensitizing cells to radiation [28]. MiRNAs such as miR-200b, miR-141, and miR-1274A correlate with improved survival post-bevacizumab therapy [58, 59]. Circulating miRNAs like miR-374a-5p and miR-519d-3p differentiate therapy responders from non-responders [18]. Redox-sensitive miRNAs may serve as biomarkers or therapeutic adjuvants to enhance radiosensitivity.

miRNAs in mitochondrial dysfunction and ROS accumulation
MiRNAs orchestrate mitochondrial homeostasis and regulate ROS levels. MiR-361-5p reduces ROS and preserves ATP production, whereas its inhibition elevates oxidative stress [43]. MiR-484, induced by OS, promotes mitochondrial injury and granulosa cell senescence by repressing SESN2 and YAP1 [41, 52]. These miRNAs also regulate NOX4 and other ROS-generating enzymes, shaping redox signaling [69].

ROS regulation of miRNA biogenesis
Oxidative stress impacts miRNA biogenesis at transcriptional, post-transcriptional, and epigenetic levels [41]. ROS impairs Drosha and Dicer, reducing the generation of mature miRNAs [72]. Hypoxia and ROS co-suppress Dicer, as exemplified by miR-630, which represses Dicer and promotes tumorigenesis [32]. Reactively generated radicals trigger the activation of key transcriptional regulators—NF-κB, NRF2, and p53—each of which subsequently influences the transcription of miRNA maturation components and their downstream targets.
Configurational epigenetic modifications, including cytosine methylation and specific acetylation/methylation of histones, fine-tune the expression of the microprocessor genes Drosha and Dicer. Dicer depletion induced by oxidative stress promotes a preponderance of onco-miRNAs while concurrently repressing miRNA species with known tumor-suppressive functions [21]. Emergent investigations reveal that m6A RNA methylation further impacts miRNA biogenesis by interacting directly with DGCR8, thereby integrating the effects of redox status into the regulatory circuitry governing miRNA maturation.

Clinical implications and translational applications of miRNAs in ovarian cancer
Within the field of clinical oncology, microRNAs (miRNAs) linked to oxidative stress have gained attention as potentially valuable biomarkers for diagnosis, prognosis, and therapeutic stratification in ovarian cancer (OC) [75]. The differential expression of these small non-coding RNAs mirrors the intrinsic heterogeneity of the neoplasm, variations in responsiveness to treatment, and the trajectory of disease progression. Their stable presence in biofluids enables their application as minimally invasive biomarkers, facilitating both early detection and longitudinal monitoring of the disease [76].

Diagnostic and prognostic biomarkers
Ovarian cancer is frequently diagnosed at late stages, emphasizing the need for early and specific biomarkers. Circulating miRNAs are attractive candidates due to their stability, tissue specificity, and resistance to RNase degradation [72]. For instance, miR-22 and miR-126 are significantly downregulated in OC serum, correlating with tumor grade and stage—with miR-22 outperforming CA-125 in diagnostic accuracy [77]. Members of the miR-200 family (miR-141, miR-200a, miR-200c) are elevated in ascitic fluid and plasma of epithelial OC patients and also regulate EMT and redox signaling [78].
MiR-21 consistently shows high expression across cancers, including OC (AUC ~ 0.87), and serves as a multi-cancer diagnostic tool [58, 59]. However, miR-484 requires further validation despite its link to oxidative stress [79]. In prognostic settings, low miR-106b-5p and miR-199b-3p levels are associated with platinum resistance and shorter survival, partly due to their regulation of ROS-related genes such as OLR1. High miR-21 expression correlates with poor overall survival. Exosomal miRNAs like miR-34a, miR-1260a, miR-320d, and miR-4479 differentiate OC patients from healthy controls and track treatment response [80]. Combining exosomal miRNAs with CA-125 enhances diagnostic precision for early detection and recurrence monitoring [81] (see Table 2).

Therapeutic strategies targeting miRNAs
Both miRNA-based approaches and therapies with PARP inhibitors offer innovative options in the treatment of ovarian cancer, working on different molecular pathways of the disease [82]. PARP inhibitors, including olaparib, have emerged as a mainstay in the treatment of ovarian cancers with BRCA mutations and those that are HRD positive, due to their apparent efficacy in advanced disease. However, development of resistance and limited effectiveness in advanced disease remains a critical hurdle [83, 84]. On the other hand, miRNA-based approaches aim to regulate the expression of particular genes that are related to tumor development, metastasis, and resistance to therapies. Some miRNAs, like miR-125a-3p, have been shown to increase sensitivity to chemotherapy and initiate apoptosis as well as senescence in ovarian cancer cells [85]. Emerging evidence supports that the combination of PARP inhibitors and compounds that modify miRNA expression or influence the DNA damage response pathways could be more effective in overcoming metastasis, highlighting the possibility of more complex treatment strategies for better results in patient care [86].
An integrated approach to ovarian cancer based on miRNA expression profiles and the use of PARP inhibitors results in greater understanding of their complementary and distinct actions. It, however, sheds light on new and exciting ways to enhance therapeutic efficacy and improve patient care (Table 3). The introduction of olaparib and subsequently, niraparib and rucaparib marked a new era in the treatment of ovarian cancer, especially for patients bearing BRCA mutations or confirmed HRD, as these drugs targeted the cancer using a neroplastic approach, taking advantage of the faulty DNA repair systems of the cancerous cells [87].
While these therapies have now become standard in maintenance treatment, resistance—both intrinsic and acquired—remains a major clinical obstacle requiring the formulation of new treatment and biomarker innovations for patient stratification [88, 89].
Strategies involving miRNAs offer the possibility of targeting the regulatory systems controlling gene expression on a higher order, including those responsible for DNA repair, responses to oxidative stress, and drug resistance [90]. As biomarkers or therapeutics, miRNAs modulate critical pathways involved in tumor growth, metastasis, and resistance to chemotherapy. For instance, miRNA-221-5p can regulate the expression of DNA damage repair genes RAD18 and RAD51. Its restoration can sensitize chemoresistant ovarian cancer cells to platinum therapies, suggesting its valorization as a therapeutic target [39, 65, 72, 91].Further, some studies indicate that the therapeutic action of PARP inhibitors may be increased and resistance diminished when miRNA modulating PARP or other DNA damage response pathway regulators are used in combination.
As an illustrative example, the dual treatment of olaparib with ATR and CHK1 inhibitors not only enhances cytotoxicity and prevents migration and invasion of ovarian cancer cell lines, but also alters miRNAs associated with metastasis and drug resistance, indicating a possible synergistic effect [86]. Moreover, the Robelin [92] study showed that miR-125a-3p, which corroborates PARP inhibition, up-regulated after PARP inhibition exposing the interplay between PARP inhibition and miRNA cross-talk. Although this work is encouraging, the majority of miRNA therapies remain preclinical, with issues of delivery, specificity, and off-target effects. In contrast to PARP inhibitors, which are well-established clinically, the therapies are limited by the frequent resistance and the precise selection of the patients [93]. The combination of miRNA strategies with PARP inhibitors and other targeted therapies is an innovative approach that will reduce resistance and improve treatment results, needing cross-validation in large, biomarker-based clinical trials [94, 95]. Thus, we could conclude that, despite the innovation of PARP inhibitors in the treatment of ovarian cancer, the synergistic strategy of PARP inhibitors with miRNA-based therapies which are aimed to alter the multi-level controllers of malignancy and therapy resistance in the malignancy is very promising [96].
The potential ovarian cancer treatments of the future are designed to effectively combine both approaches to patient-specific selection, toxicity, and therapeutic impact and patient-specific selection, toxicity, and therapeutic impact [97]. Work is ongoing to optimize these factors. Some of these include the attempts to modify the regulatory miRNA networks of redox networks and resistance mechanisms in OC:
• Platinum resistant AKT pathway inhibition by anti-miR-214 is described in Yang et al. (2008).
• Li et al. (2020) describes miR-497 suppression is associated with reduced resistance to platinum agents through S1K1/mTOR pathway downregulation. These silencing miRNAs are involved in the circuits of resistance by intertwining with oxidative stress, handling of EMT sequentials, and DNA repair.

Delivery systems for miRNA therapeutics
Effective and targeted delivery remains the cornerstone of miRNA therapy success. Naked miRNAs degrade quickly and exhibit poor tissue retention. Innovative delivery systems include:Nanoparticles (e.g., liposomes, chitosan, PLGA): Improve stability and exploit the enhanced permeability and retention (EPR) effect for tumor targeting.

Ligand-functionalized nanoparticles (e.g., folate, hyaluronic acid): Increase tumor specificity and bypass efflux transporters [98].

Exosome-based vectors: Leverage natural cellular pathways and minimize immune recognition [47].

Hydrogels and aptamer–miRNA conjugates: Allow for spatially controlled and sustained miRNA release.

Co-delivery with chemotherapeutics or antioxidants can synergistically modulate the tumor microenvironment and overcome drug resistance.

Challenges in clinical translation
The applciation of miRNA based strategies in the treatment of ovarian cancer still faces a myriad of obstacles clinically. Major concerns remain around the lack of specificity in targeting particular genes because the miRNAs can control multiple functions and genetic networks and biological interactions [70]. The delivery of miRNA mimics and inhibitors still remains a challenge. The transportation of these miRNA mimics and inhibitors to the tumor cells is still unresolved within the bounds of immunity and toxicity free systems.The ermergence of toxicity issues in clinical trials due to unestablished dosages raises safety concerns towards miRNA therapeutics [29]. The intricate miRNA networks around ovarian cancer, compounded by the lack of understanding of their roles, makes devising effective treatments exceedingly challenging [99]. Some evidence of immune mediated adverse events have also been reported in clinicals trials, The adverse effects that have been reported have not been effectively documented, therefore limiting the advancement of trials [70, 75]. There is growing optimism, however, in the development of biomedical engineering. Classifying patients through lesion spatial transcriptomics, programmable control through miRNA editing, and delivery through redox responsive systems are a few approaches that can drive precision medicine forward and reshape future clinical models [100].

Consequences and future perspectives
MicroRNAs (miRNAs) are now recognized as important modulators of gene expression within redox-related pathways, which offers diagnostic and therapeutic potential in ovarian cancer [60]. Nevertheless, their clinical application is still limited by biological, technological, and regulatory factors— COVID complexities and guidelines—diverse molecular makeup and myriad of tumor types.

Biological and clinical hurdles
The pleiotropic and context-dependent characteristics of microRNAs present formidable obstacles for clinical translation. Individual microRNAs frequently govern numerous mRNAs, producing extensive biological repertoires, which raises the risk of unintended off-target toxicity in healthy tissues [101]. Furthermore, their activity is modulated by microenvironmental gradients, the specific cancer subtype, and prevailing stress conditions,for instance, the miR-200 family can function as a suppressor under homeostatic conditions yet contribute to metastatic spread when oxidative stress is chronically elevated [102]. The separation of functionally relevant “driver” microRNAs from “passenger” bystanders remains a major analytical challenge, as overlapping, compensatory circuits among miRNA families mask the phenotypic consequences of individual family members. Compounding this, subtype-specific miRNA expression signatures in high-grade serous, endometrioid, and clear-cell ovarian carcinomas further constrain the reach of generic miRNA-directed therapies [103]. Moreover, the pervasive crosstalk among miRNAs, long non-coding RNAs, and circular RNAs introduces additional, poorly characterized layers of regulatory control.

Technological innovations
Recent technical advances offer pathways to mitigate these complexities. Single-cell RNA sequencing and spatial transcriptomics now permit high-resolution quantification of redox-sensitive microRNAs within morphologically and functionally diverse tumor microregions [104]. Concurrently, artificial intelligence and machine-learning algorithms are being harnessed to model platinum resistance, delineate miRNA-mRNA regulatory circuits, and identify patients at elevated risk of aggressive disease progression [105]. Patient-derived organoids (PDOs constitute a three-dimensional in vitro model that faithfully recapitulates the genetic and phenotypic heterogeneity of the original tumor, thus enabling the dissection of microRNA-targeting strategies and the quantification of oxidative stress responses in a biologically relevant context,these characteristics render PDOs a powerful tool for the iterative refinement of personalized therapeutic regimens [106].

Delivery and pharmacokinetic challenges
Despite technological advances, miRNA pharmacokinetics and targeted delivery remain major obstacles. Unmodified miRNAs degrade rapidly in circulation and have limited cellular uptake due to negative charge and size [107].
Nanotechnology-based platforms improve stability, cellular uptake, and tumor specificity. Examples include:Lipid nanoparticles for prolonged circulation

Polymeric carriers for improved uptake under hypoxic conditions

Exosomes, offering natural targeting and low immunogenicity [98]

Smart delivery systems that respond to tumor pH, ROS levels, or temperature gradients enable controlled payload release. Dual-function nanocarriers are also being developed to simultaneously deliver miRNAs and scavenge ROS.
However, limitations persist in terms of scalability, batch reproducibility, and targeting specificity for clinical use. Figure 4 therapeutic strategies targeting miRNAs in ovarian cancer (see Table 4).

CRISPR technology in miRNA therapeutics
CRISPR/Cas systems offer high-precision tools to edit miRNAs or their upstream regulators. For instance, CRISPR/Cas9-mediated knockout of miR-21 suppresses proliferation and sensitizes tumors to chemotherapy in OC models [15]. CRISPR/Cas13 allows direct editing of mature miRNAs or untranslated regions, enhancing control over non-coding RNA pathways [7]. Nanocarrier-assisted CRISPR delivery systems have shown improved tumor targeting and editing efficiency [108]. However, standardized protocols for miRNA normalization and reproducibility are still lacking [109], and immune-related toxicity and dosing uncertainties have limited clinical progress (e.g., MRX34, TargomiR) [63]. Nanocarrier and CRISPR-based miRNA therapeutics hold significant promise for advancing ovarian cancer treatment, yet their clinical translation is hampered by critical challenges such as toxicity, delivery efficiency, and specificity [15]. Nanocarriers, including DNA origami and various nanoparticle systems, can protect miRNA cargo from degradation and enhance tumor targeting, but issues remain regarding off-target effects, immunogenicity, and the potential for toxicity in healthy tissues [110]. The biological barriers and the diversity within tumor microenvironments make effective and accurate delivery to ovarian cancer cells the risk of side effects [111]. For CRISPR miRNA therapeutics, the primary concerns involve the delivery of gene-editing materials, off-target edits, and immune response [112, 113]. Improvements in targeting and decreases in toxicity are being worked on through the use of antibody-conjugated and extracellular vesicle-based delivery systems, but these methods are not ready for the clinic yet, and much work remains and optimization is needed [82, 112]. In any case, without first these problems being solved, the full therapeutic potential of nanocarrier and CRISPR miRNA on ovarian cancer therapies will remain unrealized [114].

Future research directions
Future work should concentrate on the following to enable clinical translation:
•Targetable redox-responsive systems for miRNA delivery.
•Multicenter trials evaluating the diagnostic and prognostic value of specific miRNA panels.
•Redox phenotyping in combination with dynamic miRNA expression analysis to identify actionable environmental vulnerabilities.
The advancement of personalized medicine for ovarian cancer (OC) will be fueled by the integration of miRNA analytics, redox biology, and precision delivery systems.

Validation challenges of microRNA‐based biomarkers
Validating the microRNA (miRNA) biomarkers in ovarian cancer with focus on oxidative stress, disease diagnosis, its mechanisms, and therapeutic resistance, poses some substantial hurdles. One of the main challenges is reproducibility across patient populations and techniques. Some studies indicate that while certain specific miRNA panels can accurately distinguish ovarian cancer cases from controls with high accuracy in the initial dataset, these panels often do not retain discriminatory accuracy in external validation cohorts. This is often due to the heterogeneity of the population, sample collection and processing methods that introduce confounding factors and limit the generalizability of the results [115, 116]. Other factors that complicate the validation of miRNA biomarkers are technical issues. The extraction and quantification of specific miRNAs, especially in exosomes or other extracellular vesicles, is very method-sensitive [117]. Fluctuations in techniques used to isolate exosomes will impact the purity and yield of miRNAs, resulting in differences in expression profiles and how well they serve as a diagnostic indicator. Standardized protocols for miRNA extraction and normalization, which are lacking, make cross-study comparisons impossible and limit the clinical translation of promising biomarkers [118]. Tumor biological variability, such as tumor and patient population heterogeneity, adds to these complications. Ovarian cancer is a subtype heterogeneous disease with multiple subtypes, each with its own distinct molecular and miRNA expression profiles [119]. Stage, subtype, and even the presence of other diseases can alter miRNA levels which complicates the ability to identify universal markers [120]. Therefore, to attain robust diagnostic accuracy, a diverse and large population is needed in order to validate panels of multiple miRNAs that are needed and ensure their clinical utility [121]. Integrating miRNA biomarkers with other diagnostic methods poses yet another challenge. The inclusion of miRNA panels alongside established protein markers such as CA-125 have proven to greatly enhance diagnostic accuracy, especially in early-stage ovarian cancer. But, to create joint models that include miRNA, protein, and clinical metadata, you need to use advanced statistics and machine learning, and these models need to be validated in other groups to make sure they work and can be reliably duplicated [122]. Ultimately, clinical translation of miRNA biomarkers is challenging due to the lack of primary large-scale, multi-center studies and multi-omic data integration.The vast amount of data generated from preclinical and clinical studies must be harmonized and analyzed using advanced bioinformatics tools [116]. Only through coordinated efforts to standardize methodologies, improve cohort diversity, and leverage integrative data analysis can reliable miRNA biomarkers be identified and validated for clinical use [118].

Conclusion
The interplay between oxidative stress and dysregulated miRNAs is central to the initiation, progression, and therapeutic resistance of ovarian cancer. This review underscores how the reciprocal regulation between oxidative stress and miRNAs forms a feedback loop that modulates key oncogenic processes, including apoptosis evasion, epithelial–mesenchymal transition, angiogenesis, and chemoresistance. Redox-sensitive miRNAs, such as miR-29b, miR-200c, and miR-21, serve dual functions as both biomarkers and therapeutic targets, with their detectability in biofluids and tumor tissues supporting their application in non-invasive diagnostics and disease monitoring. We can now map miRNA-redox interactions with spatial transcriptomics, single-cell RNA sequencing, artificial intelligence modeling, and other emerging technologies. These innovations also improve the spatial and temporal precision with which miRNA-targeted therapies can be delivered. Although, issues like targeted delivery, drug metabolism, and how the body’s immune system would respond to the treatment, still makes it difficult to apply these methods in practice. The problem and treatment methods need to be combined. For instance, chemotherapy and immunotherapy can be combined with miRNA-based therapies to improve efficacy and treatment sustainability. We can use the miRNA regulation associated with oxidative stress to advance precision medicine in pediatric patients with long-term treatment resistance in advanced-stage ovarian cancer.