Search Results (332)

Background: Methylthioadenosine phosphorylase (MTAP) deficiency caused by homozygous deletion is prevalent in solid tumors and contributes to malignant progression, thereby rendering cancer cells vulnerable to dysfunction of protein arginine methyltransferase 5 (PRMT5). This study aimed to investigate whether Poly (ADP-ribose) polymerase (PARP) inhibitors could exploit this vulnerability through PRMT5 inactivation in MTAP-deficient tumors. Methods: PRMT5 activity was assessed in vitro and in vivo following PARP inhibitor treatment. The antitumor effects of PARP inhibitors alone or in combination with either the MTAP inhibitor MTDIA or the PRMT5 inhibitor EPZ015666 were evaluated in solid tumor models, including MTAP-deficient tumor models in vivo. Results: PARP inhibitors effectively inactivated PRMT5 in vitro and in vivo and exacerbated DNA double-strand breaks induced by PARP inhibition. Moreover, PARP inhibitors showed significant synergistic effects when combined with either MTDIA or EPZ015666 in solid tumor models. MTAP-deficient tumors exhibited increased vulnerability to olaparib in vivo, and combined treatment with olaparib plus MTDIA or EPZ015666 produced improved therapeutic outcomes compared with olaparib alone. Conclusions: These findings identify PARP inhibitors as a potential therapeutic strategy for MTAP-deficient tumors through targeted inactivation of PRMT5 and support further evaluation of PARP inhibitor-based combination therapies in this molecular context. Full article

Objective: To compare real-world PFS between BEV and OLA as maintenance therapy for PSROC, with an exploratory evaluation of clinical outcomes after OLA dose reduction. Methods: This retrospective multicenter study included 101 patients with first platinum-sensitive recurrent ovarian, fallopian tube, or primary peritoneal cancer who achieved a response to platinum-based chemotherapy and then received maintenance therapy. Patients were classified into three groups: BEV (n = 34), standard-dose OLA (n = 31), and dose-reduced OLA (n = 36). The primary endpoint was PFS; secondary endpoints were OS and adverse events. Survival outcomes were evaluated using Kaplan–Meier methods and Cox proportional hazards models. Results: In the primary comparison of all OLA-treated patients versus BEV, OLA was associated with longer PFS (HR 0.48, 95% CI 0.29–0.77), with median PFS of 19 months versus 16 months, respectively. OS did not differ significantly between groups (HR 0.60, 95% CI 0.34–1.05). In exploratory subgroup analyses, patients who underwent OLA dose reduction had numerically longer PFS than those who remained on the full dose; however, this comparison is vulnerable to time-dependent and selection biases and should be interpreted cautiously. Grade ≥ 3 hematologic toxicities were more frequent in the OLA groups but were clinically manageable. Conclusions: In real-world practice, OLA was associated with longer PFS than BEV in PSROC. Clinically necessary dose reduction appeared feasible without an obvious loss of benefit, although this finding requires cautious interpretation. Full article

Background/Objectives: Combinations of PARP inhibitors (PARPi) and androgen receptor pathway inhibitors (ARPi) have led to clinical success in treating advanced prostate cancer. However, it is unclear where in the clinical paradigm these combinations will fare best, and their mechanism of action remains unclear. We sought to address open questions and explore alternative strategies to enhance PARPi efficacy. Methods: Viability and morphology were assessed in response to (1) abiraterone, olaparib, or combination and (2) enzalutamide, talazoparib, or combination in castration-resistant C4-2B cells and abiraterone- or enzalutamide-resistant derivative cell models (ARPi-resistant). The efficacy of the ATM inhibitor lartesertib with and without a PARPi was also determined. Western blots and RNA-sequencing were used to interrogate the mechanistic effects of treatment. Results: PARPi and ARPi combinations were effective in all models but provided the most benefit in ARPi-sensitive C4-2B cells. Mechanistically, ARPi was not found to affect homologous recombination repair gene expression but may increase PARP activity. Prolonged PARP inhibition was found to increase the expression of AR target genes, and PARPi pre-treatment increased sensitivity to enzalutamide. ATM inhibition significantly increases PARPi efficacy and appears to outperform ARPi-containing combinations in ARPi-resistant models. Conclusions: PARPi and ARPi combinations are effective in ARPi-resistant models, but efficacy appears stronger in ARPi-sensitive CRPC cells. Presented findings support a novel hypothesis that PARP inhibition may increase ARPi sensitivity with increasing AR activity. Additionally, ATM inhibition may provide more benefit than an ARPi in combination with a PARPi in ARPi-resistant settings. These findings support continued PARPi development for improving patient outcomes. Full article

Background: Poly(ADP-ribose) polymerase inhibitors (PARPis) are established maintenance therapies in epithelial ovarian cancer (EOC). Although considered relatively safe, their impact on renal function remains unclear. Increases in serum creatinine (SCr) are frequently observed during treatment, but the clinical significance of these changes is uncertain. We conducted a systematic review and meta-analysis to assess the risk of renal adverse events associated with PARPis in randomized controlled trials (RCTs). Methods: PubMed/MEDLINE, Embase, and the Cochrane Library were searched for phase II–III, placebo-controlled RCTs published through 30 June 2025. Eligible studies enrolled patients with ovarian cancer receiving maintenance monotherapy with olaparib, niraparib, rucaparib, or fuzuloparib and reported renal adverse events. The primary endpoint was creatinine increase (all grades). Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using fixed- or random-effects models according to heterogeneity. Results: Nine high-quality RCTs comprising 2578 patients met the inclusion criteria. PARPi therapy was associated with a significantly increased risk of creatinine elevation compared with placebo (OR 5.04; 95% CI 3.51–7.24; p < 0.001). Heterogeneity was moderate (I² = 31.7%). High-grade renal adverse events (≥grade 3) were rare (<1%) and could not be reliably pooled. No significant publication bias was detected. Conclusions: PARP inhibitors significantly increase the likelihood of SCr elevation in EOC; however, severe nephrotoxicity appears uncommon in RCTs. Observed SCr increases may partly reflect inhibition of renal tubular creatinine transport rather than true reductions in glomerular filtration. Careful renal monitoring and prospective studies incorporating direct GFR assessment are warranted. Full article

Background/Objectives: Epirubicin, Olaparib, and Ribociclib are widely used anticancer agents whose serum concentrations exhibit significant inter-individual variability, supporting the need for reliable and robust analytical methods suitable for pharmacokinetic evaluation and therapeutic exposure assessment. Variations in metabolism, drug–drug interactions, organ function, and treatment regimens may substantially influence systemic exposure, highlighting the importance of accurate quantification in clinical practice. This study describes the development and validation of a solid-phase extraction–liquid chromatography–mass spectrometry (SPE–LC–MS) method for the simultaneous quantification of these drugs in human serum. Methods: Sample preparation was performed using Oasis PRiME HLB^® cartridges to ensure efficient clean-up, optimal recovery, and reduced matrix effects. Chromatographic separation was achieved using gradient elution with 0.1% formic acid and acetonitrile on a reversed-phase column, followed by single-quadrupole mass spectrometric (QDa) detection in the selected ion recording mode. The total run time was 13 min, enabling high-throughput analysis. Results: The method demonstrated good linearity (r > 0.997) over the tested concentration ranges, along with adequate selectivity, precision, accuracy, recovery, and stability, fulfilling the ICH M10 guideline validation criteria. No significant carry-over or interference from endogenous compounds was observed. Conclusions: Application to patient samples confirmed reliable performance in real clinical matrices and consistent quantification across different concentration levels. The proposed approach provides a potentially more accessible alternative in laboratories already equipped with LC-MS systems compared to LC-MS/MS platforms and can be applied in pharmacokinetic studies, representing a proof-of-concept for exposure assessment in oncology. Full article

Breast cancer remains a major global health challenge, requiring novel therapeutic strategies that can overcome drug resistance and improve treatment efficacy. This study investigates the synergistic antitumor effects of etoposide, a conventional chemotherapeutic agent, and resveratrol, a natural polyphenol with anticancer properties, in human breast cancer cell lines, with particular focus on their ability to activate the parthanatos cell death pathway. Using MCF-7 (estrogen receptor-positive) and MDA-MB-231 (triple-negative) breast cancer cells, we assessed cell viability via MTT assays and evaluated parthanatos activation through multiple complementary approaches including AIF translocation determined by subcellular fractionation, NAD+ depletion measurement, and gene expression analysis. Synergy was quantified using the Chou–Talalay method across multiple effect levels (ED50, ED75, ED90). To establish causality, Olaparib PARP inhibitor experiments were performed to confirm that PARP-1 hyperactivation is essential for the observed cytotoxic effects. The results demonstrated that the etoposide–resveratrol combination significantly enhanced cell death and inhibited proliferation compared to single-agent treatments, with combination index (CI) values indicating strong synergism (CI = 0.62–0.75 for MCF-7; CI = 0.58–0.71 for MDA-MB-231). This synergy was associated with robust parthanatos activation, evidenced by increased PARP-1 expression, AIF nuclear translocation confirmed by subcellular fractionation, and significant NAD+ depletion. Critically, Olaparib pre-treatment (3 µM) significantly rescued cells from combination-induced death, restored NAD+ levels to near-control values, and prevented AIF translocation, establishing a causal link between PARP-1 hyperactivation and parthanatos-mediated cytotoxicity. The combination also induced significant DNA fragmentation, elevated oxidative stress, and cell death with morphological features consistent with parthanatos, while caspase activity remained low, confirming caspase-independent cell death. These findings suggest that targeting parthanatos with etoposide and resveratrol could offer a promising therapeutic strategy for breast cancer, potentially overcoming resistance and improving efficacy. Further in vivo studies and clinical investigations are needed to validate these results and explore translational applications. Full article

Background: Breast cancer (BC) is one of the most diagnosed malignancies and a leading cause of cancer-related mortality among women worldwide, thereby posing a substantial threat to women’s health worldwide. However, clinically robust diagnostic biomarkers with high sensitivity and specificity, as well as well-validated molecular targets for targeted therapy, remain limited. Methods: BC transcriptomic data from seven GEO datasets and the TCGA-BRCA cohort (n = 1231) were integrated for analysis. After batch-effect correction, candidate genes were screened through DEA, WGCNA, and PPI networks analysis. An ensemble machine learning (ML) framework incorporating 127 algorithmic combinations was constructed, and SHAP analysis was applied to identify hub genes. Further analyses included functional enrichment, immune infiltration, miRNA regulatory network analysis, and SMR analysis. The expression patterns were validated using single-cell transcriptome data. Drug repositioning analysis and AI-assisted virtual screening were performed to prioritize compounds with favorable drug-like properties. The predicted binding modes of candidate compounds with CHEK1 were assessed by molecular docking. Results: Thirty core genes were obtained through differential expression, WGCNA, and PPI screening. Integrated ML (127 algorithms) determined the optimal model (AUC = 0.919), and SHAP identified nine feature genes, among which CHEK1 and KIF23 showed preliminary diagnostic potential across four external cohorts (AUC: 0.625–0.938). Functional enrichment indicated that both are enriched in the cell cycle and p53 pathways, closely associated with BRCA1/ATR; immune infiltration revealed significant correlations with macrophages and CD8⁺ T cells, with hsa-miR-15a-5p and hsa-miR-607 being common upstream regulatory miRNAs. SMR analysis supported a causal relationship between CHEK1 expression and BC genetic susceptibility (p_SMR < 0.05, p_HEIDI > 0.05); single-cell analysis confirms its heterogeneous expression. AI-assisted virtual screening identified 25 A-grade computational candidate compounds from 171 candidates. Molecular docking suggested that Olaparib and LY294002 can form favorable interactions with the CHEK1 active pocket. Conclusions: The study identified CHEK1 as a key diagnostic gene for BC through 127 ML algorithms and SMR causal inference. By combining AI-assisted virtual screening and molecular docking, computational candidate compounds targeting CHEK1 were prioritized. These findings represent hypothesis-generating in silico predictions and require experimental validation before any therapeutic conclusions can be drawn. Full article

Triple-negative breast cancer (TNBC) cells with intact homologous recombination (HR) repair mechanism can survive treatment with Olaparib, which further limits the clinical application of PARP1/2 inhibitors. Previous studies have demonstrated that inhibition of indoleamine 2,3-dioxygenase (IDO) can enhance the sensitivity of human tumor cells to PARP1/2 inhibitors. However, the mechanisms underlying their synergistic effects in the treatment of TNBC remain unclear. Herein, we demonstrate that the combination of Olaparib and Epacadostat significantly reduces the proliferation of BRCA-proficient MDA-MB-231 and MDA-MB-468 cells compared to either monotherapy. Mechanistically, Epacadostat reduces intracellular kynurenine and NAD⁺ levels, thereby sensitizing TNBCs to PARP1/2 inhibition and significantly amplifying Olaparib-induced DNA damage. Furthermore, Epacadostat and Olaparib synergistically increase cellular reactive oxygen species (ROS), leading to DNA oxidative damage and apoptosis. In vivo, Epacadostat and Olaparib significantly suppressed MDA-MB-468 tumor growth compared to the monotherapy groups, while promoting an increase in phosphorylated H2AX. Notably, the dual inhibition of IDO1 and PARP1/2 specifically reduced the expression of HR core genes and proteins, such as BRCA1 and RAD51, which may contribute to impaired DNA-damage repair and increased sensitivity to Olaparib. In summary, targeting both IDO1 and PARP1/2 represents a promising combination therapy for BRCA-proficient TNBC. Full article

Heat-shock factor 1 (HSF1) is a multifunctional transcription factor whose overexpression is associated with the development, progression, and aggressiveness of several tumor types, including hepatocellular carcinoma (HCC). In the present study, we thoroughly investigated the antitumor activity of NXP800, a recently developed HSF1 inhibitor that is currently tested in clinical trials, on HCC growth. We discovered that NXP800 inhibits the cell growth of human HCC cell lines by reducing proliferation, inducing apoptosis, and causing DNA damage. At the metabolic level, NXP800 significantly decreased mitochondrial respiration, which was associated with extensive structural alterations in the mitochondria, and reduced glycolysis of HCC cells. At the molecular level, NXP800 administration led to the upregulation of the integrated stress response and downregulation of the E2F1 signaling cascade. In addition, NXP800 profoundly constrained the growth of HCC patient-derived organoids. Furthermore, NXP800 antitumor properties were significantly augmented when NXP800 was coupled with the DNA-damaging agent doxorubicin or the PARP inhibitor olaparib. Our investigation indicates that NXP800 has significant antitumor activity and might represent a promising therapeutic agent for the treatment of human HCC. Full article

The design, production, and study of new poly[ADP-ribose] polymerase 1 (PARP-1) inhibitors have emerged as an interesting exploration area, since PARP-1 is an overexpressed enzyme in several carcinomas. In this sense, menadione, or vitamin K3, is well known for its use in correct blood clotting, and for the generation of reactive oxygen species, but it is important to mention that it has been used as an antineoplastic agent against several cell lines. Related to the last commentary, in this work, four novel molecules (2–5) were produced from menadione through a Michael addition protocol, using 1,2-ethanedithiol, cysteamine, benzene-1,4-dithiol, and 4-aminobenzenethiol as nucleophiles, and menadione (1) as substrate, to evaluate them as plausible candidates to inhibit PARP-1. It is convenient to note that after their production and spectroscopic characterization, both docking and theoretical studies for each compound were conducted, using density functional theory (DFT) with the hybrid method B3LYP with the 6-311G(d,p) basis set. As a complement, the reactivity properties determined by DFT calculations were obtained for all compounds; the results revealed that 2 has the best properties to bind with PARP-1, and 3 offered good results. Hence, the target compounds were evaluated in vitro, determining their activity against PARP-1, using olaparib as a reference. Molecules 2 and 3 displayed the free binding energy values −7.97 and −9.35 kcal/mol, respectively, but 2 has the best IC₅₀ value, 13.76 µM. It is important to highlight that 2 and 3 must be considered as potential new inhibitor agents against PARP-1, exhibiting competitive IC₅₀ values with olaparib. Full article

Ovarian cancer is a devastating disease that is often diagnosed in the late stages. The typical therapeutic approach includes surgery plus cytotoxic drugs such as carboplatin and paclitaxel. In recent years, the advent of poly ADP-ribose polymerase (PARP) inhibitors such as olaparib has offered additional treatment opportunities for patients with BRCA mutations or homologous recombination deficiencies. Nevertheless, resistance to therapy usually occurs, leading to poor overall survival. Therefore, novel treatments are needed for this disease. One of the obstacles to successful treatment is the highly immunosuppressive nature of the ovarian cancer microenvironment. Recent strategies for the treatment of ovarian cancer and other types of cancer involve targeting the metabolism of cancer cells and other cells of the tumor microenvironment. One drug that has been investigated both in preclinical studies and clinical trials as an antitumor agent is metformin. This drug, typically used for the treatment of type-2 diabetes for its capability to lower blood glucose, can directly affect cancer cell growth and survival by activating the AMPK (adenosine monophosphate-activated protein kinase) pathway. Furthermore, it can affect the phenotype of other cells of the tumor microenvironment such as macrophages and T cells. In this review, we summarize the main characteristics of ovarian cancer and describe preclinical studies and clinical trials involving metformin as a therapeutic agent for this disease. Full article

Poly(ADP-ribose) polymerase (PARP) inhibitors exploit defects in homologous recombination (HR) but show limited and heterogeneous efficacy in non-small-cell lung cancer (NSCLC), where canonical HR deficiency is uncommon. Identifying alternative molecular determinants that modulate PARP inhibitor sensitivity therefore remains an important objective. In this study, we examined the role of the NDR/Hippo-associated cofactor human MOB2 (hMOB2) in shaping PARP inhibitor responses in lung cancer cells. hMOB2 was depleted by siRNA in A549 and H1299 cell lines, and cell viability, long-term survival, DNA damage, and apoptosis were assessed using WST-1 assays, clonogenic assays, Western blotting, immunofluorescence, comet assays, and caspase-3 activity assays. p53 dependency was evaluated using p53-null H1299 cells and p53 reconstitution via retroviral transduction. hMOB2 depletion sensitized A549 cells to olaparib and rucaparib, resulting in a marked reduction in long-term clonogenic survival. This effect was associated with enhanced p53 phosphorylation, persistent γH2AX accumulation, increased DNA strand breaks, and caspase-3-dependent apoptosis, while hMOB2 loss alone was not intrinsically cytotoxic. Sensitization required functional p53, as it was absent in p53-null cells but restored upon p53 re-expression. These findings suggest that hMOB2 contributes to PARP inhibitor responses in lung cancer cells and underscore the complexity of PARP inhibitor sensitivity beyond classical HR deficiency. Full article

The glioma tumor microenvironment (TME) exhibits profound heterogeneity that drives tumor progression and therapy resistance. By integrating single-cell RNA sequencing (eleven samples) and spatial transcriptomics (two samples), the cellular components of the glioma microenvironment were deconvoluted, revealing tumor-associated foam cells (TAFCs) as the most abundant and centrally connected subtype. The high expression of two prognostic candidate genes, growth differentiation factor 8 (GDF-8, also known as myostatin, MSTN) and transcription factor 12 (TCF12), in TAFCs was found to be correlated with poor overall survival. These two genes were associated with M2 macrophage infiltration, altered cholesterol homeostasis, and immunosuppressive signaling. Regulatory network and pathway analyses, based on computational motif enrichment and co-expression analysis, linked them to ribosome, Notch signaling, DNA repair, and cell-cycle pathways. Pseudotime trajectories revealed dynamic expression during differentiation. Additionally, drug sensitivity prediction analysis demonstrated that MSTN expression was significantly associated with sensitivity to paclitaxel and VE-822, while TCF12 expression showed potential associations with sensitivity to cytarabine, olaparib, Wee1 inhibitor, paclitaxel, and VE-822. Logistic regression analysis combining clinical parameters with MSTN and TCF12 expression effectively achieved risk stratification for glioma, with higher composite scores predicting worse 2- and 3-year survival outcomes. Calibration curves demonstrated high consistency between nomogram-predicted overall survival probabilities and actual observed outcomes. Immunofluorescence confirmed upregulated expression of MSTN and TCF12 in glioma tissues and their co-localization with macrophages. In conclusion, this study identified TAFCs as the central cells in the glioma microenvironment, with their signature genes MSTN and TCF12 representing candidate immunometabolic signatures associated with macrophage-mediated immunosuppression and metabolic reprogramming in glioma, suggesting their potential as biomarkers for patient stratification and as targets for immunometabolic therapies. Full article

Background: Poly(ADP-ribose) polymerase (PARP) inhibitors have been established as a first-line maintenance therapy in advanced epithelial ovarian cancer (EOC) following platinum-based chemotherapy. While phase III trials have demonstrated significant progression-free survival (PFS) benefits with olaparib and niraparib, real-world data remain limited. Methods: This retrospective, multicenter real-world study included 179 patients with newly diagnosed epithelial ovarian treated with first-line maintenance olaparib or niraparib across 33 centers in Türkiye between January 2014 and March 2025. Clinical, pathological, and molecular data—including BRCA (Breast Cancer Susceptibility Gene) mutation status, origin, and variant classification—was collected. The primary endpoint was PFS, and secondary endpoints included overall survival (OS) and safety. Survival outcomes were analyzed using Kaplan–Meier methods. Results: Of 179 patients, 110 received olaparib and 69 received niraparib. BRCA mutations were present in 88.3% of patients, while 11.7% had unknown HRD status. Median follow-up was 16.5 months, and median PFS was not reached. Estimated PFS rates for the overall cohort were 91.0% at 6 months, 83.0% at 12 months, and 64.0% at 24 months. In the olaparib cohort, BRCA-mutant patients demonstrated PFS rates of 89%, 78%, 73%, and 64% at 6, 12, 18, and 24 months, respectively. In the niraparib cohort, corresponding PFS rates among BRCA-mutant patients were 87% at 6 months and 75% at 12 months. Patients harboring pathogenic BRCA variants experienced longer PFS compared with those with likely pathogenic variants. Any-grade adverse events occurred in 73.7% of patients, and grade 3–4 events in 29.6%, with hematologic toxicities predominating. Dose interruptions were more frequent with niraparib, while treatment discontinuation rates were low in both groups. No cases of myelodysplastic syndrome or acute myeloid leukemia were observed. Conclusions: In this large multicenter real-world cohort, first-line maintenance therapy with olaparib and niraparib provided durable PFS benefit in patients with advanced EOC, particularly among those with pathogenic BRCA mutations, confirming their effectiveness and manageable safety profiles in routine clinical practice. Full article

Poly(ADP-ribose) polymerases (PARPs) regulate genome maintenance through NAD⁺-dependent ADP-ribosylation, yet PARP function in fungi remains poorly defined. Here, we reconstituted the activity of the Magnaporthe oryzae PARP1 homolog (MoPARP1) in Saccharomyces cerevisiae, a genetically tractable organism that lacks endogenous PARP enzymes. Upon galactose induction, expression of MoPARP1 reduced yeast growth, whereas a catalytically inactive mutant showed no defect, indicating that the growth phenotype depends on PARP catalytic activity. Consistent with this requirement, PARylation was detected in MoPARP1-expressing yeast cells but not in the catalytic mutant. In a multidrug transporter-deficient background, the PARP inhibitor 3-aminobenzamide and the clinically used PARP inhibitor olaparib rescued the growth of MoPARP1-expressing strains, establishing a framework for inhibitor testing in vivo. Finally, MoPARP1-GFP localized to the nucleus independent of catalytic activity, supporting correct targeting in this heterologous system. Together, these findings establish yeast as a platform to dissect fungal PARP biology and evaluate chemical inhibition. Full article