Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy.

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Circular RNA hsa_circ_0000467 promotes colorectal cancer progression by promoting eIF4A3-mediated c-Myc translation.

BACKGROUND: Colorectal cancer (CRC) is the second most common malignant tumor worldwide, and its incidence rate increases annually. Early diagnosis and treatment are crucial for improving the prognosis of patients with colorectal cancer. Circular RNAs are noncoding RNAs with a closed-loop structure that play a significant role in tumor development. However, the role of circular RNAs in CRC is poorly understood. METHODS: The circular RNA hsa_circ_0000467 was screened in CRC circRNA microarrays using a bioinformatics analysis, and the expression of hsa_circ_0000467 in CRC tissues was determined by in situ hybridization. The associations between the expression level of hsa_circ_0000467 and the clinical characteristics of CRC patients were evaluated. Then, the role of hsa_circ_0000467 in CRC growth and metastasis was assessed by CCK8 assay, EdU assay, plate colony formation assay, wound healing assay, and Transwell assay in vitro and in a mouse model of CRC in vivo. Proteomic analysis and western blotting were performed to investigate the effect of hsa_circ_0000467 on c-Myc signaling. Polysome profiling, RT‒qPCR and dual-luciferase reporter assays were performed to determine the effect of hsa_circ_0000467 on c-Myc translation. RNA pull-down, RNA immunoprecipitation (RIP) and immunofluorescence staining were performed to assess the effect of hsa_circ_0000467 on eIF4A3 distribution. RESULTS: In this study, we found that the circular RNA hsa_circ_0000467 is highly expressed in colorectal cancer and is significantly correlated with poor prognosis in CRC patients. In vitro and in vivo experiments revealed that hsa_circ_0000467 promotes the growth and metastasis of colorectal cancer cells. Mechanistically, hsa_circ_0000467 binds eIF4A3 to suppress its nuclear translocation. In addition, it can also act as a scaffold molecule that binds eIF4A3 and c-Myc mRNA to form complexes in the cytoplasm, thereby promoting the translation of c-Myc. In turn, c-Myc upregulates its downstream targets, including the cell cycle-related factors cyclin D2 and CDK4 and the tight junction-related factor ZEB1, and downregulates E-cadherin, which ultimately promotes the growth and metastasis of CRC. CONCLUSIONS: Our findings revealed that hsa_circRNA_0000467 plays a role in the progression of CRC by promoting eIF4A3-mediated c-Myc translation. This study provides a theoretical basis and molecular target for the diagnosis and treatment of CRC.

Application of PARP inhibitors combined with immune checkpoint inhibitors in ovarian cancer.

The advent of polyadenosine diphosphate ribose polymerase inhibitors (PARPi) has brought about significant changes in the field of ovarian cancer treatment. However, in 2022, Rucaparib, Olaparib, and Niraparib, had their marketing approval revoked for third-line and subsequent therapies due to an increased potential for adverse events. Consequently, the exploration of new treatment modalities remains imperative. Recently, the integration of PARPi with immune checkpoint inhibitors (ICIs) has emerged as a potential remedy option within the context of ovarian cancer. This article offers a comprehensive examination of the mechanisms and applications of PARPi and ICIs in the treatment of ovarian cancer. It synthesizes the existing evidence supporting their combined use and discusses key considerations that merit attention in ongoing development efforts.

The roles and molecular mechanisms of non-coding RNA in cancer metabolic reprogramming.

One of the key features of cancer is energy metabolic reprogramming which is tightly related to cancer proliferation, invasion, metastasis, and chemotherapy resistance. NcRNAs are a class of RNAs having no protein-coding potential and mainly include microRNAs, lncRNAs and circRNAs. Accumulated evidence has suggested that ncRNAs play an essential role in regulating cancer metabolic reprogramming, and the altered metabolic networks mediated by ncRNAs primarily drive carcinogenesis by regulating the expression of metabolic enzymes and transporter proteins. Importantly, accumulated research has revealed that dysregulated ncRNAs mediate metabolic reprogramming contributing to the generation of therapeutic tolerance. Elucidating the molecular mechanism of ncRNAs in cancer metabolic reprogramming can provide promising metabolism-related therapeutic targets for treatment as well as overcome therapeutic tolerance. In conclusion, this review updates the latest molecular mechanisms of ncRNAs related to cancer metabolic reprogramming.

Rac1 promotes the reprogramming of glucose metabolism and the growth of colon cancer cells through upregulating SOX9.

Metabolic reprogramming is the survival rule of tumor cells, and tumor cells can meet their high metabolic requirements by changing the energy metabolism mode. Metabolic reprogramming of tumor cells is an important biochemical basis of tumor malignant phenotypes. Ras-related C3 botulinum toxin substrate 1 (Rac1) is abnormally expressed in a variety of tumors and plays an important role in the proliferation, invasion, and migration of tumor cells. However, the role of Rac1 in tumor metabolic reprogramming is still unclear. Herein, we revealed that Rac1 was highly expressed in colon cancer tissues and cell lines. Rac1 promotes the proliferation, migration, and invasion of colon cancer cells by upregulating SOX9, which as a transcription factor can directly bind to the promoters of HK2 and G6PD genes and regulate their transcriptional activity. Rac1 upregulates the expression of SOX9 through the PI3K/AKT signaling pathway. Moreover, Rac1 can promote glycolysis and the activation of the pentose phosphate pathway in colon cancer cells by mediating the axis of SOX9/HK2/G6PD. These findings reveal novel regulatory axes involving Rac1/SOX9/HK2/G6PD in the development and progression of colon cancer, providing novel promising therapeutic targets.

LPLUNC1 reduces glycolysis in nasopharyngeal carcinoma cells through the PHB1-p53/c-Myc axis.

Cancer cells prefer glycolysis to support their proliferation. Our previous studies have shown that the long palate, lung, and nasal epithelial cell clone 1 (LPLUNC1) can upregulate prohibitin 1 (PHB1) expression to inhibit the proliferation of nasopharyngeal carcinoma (NPC) cells. Given that PHB1 is an important regulator of cell energy metabolism, we explored whether and how LPLUNC1 regulated glucose glycolysis in NPC cells. LPLUNC1 or PHB1 overexpression decreased glycolysis and increased oxidative phosphorylation (OXPHOS)-related protein expression in NPC cells, promoting phosphorylated PHB1 nuclear translocation through 14-3-3σ. LPLUNC1 overexpression also increased p53 but decreased c-Myc expression in NPC cells, which were crucial for the decrease in glycolysis and increase in OXPHOS-related protein expression induced by LPLUNC1 overexpression. Finally, we found that treatment with all-trans retinoic acid (ATRA) reduced the viability and clonogenicity of NPC cells, decreased glycolysis, and increased OXPHOS-related protein expression by enhancing LPLUNC1 expression in NPC cells. Therefore, the LPLUNC1-PHB1-p53/c-Myc axis decreased glycolysis in NPC cells, and ATRA upregulated LPLUNC1 expression, ATRA maybe a promising drug for the treatment of NPC.

Impacts and mechanisms of alternative mRNA splicing in cancer metabolism, immune response, and therapeutics.

Alternative pre-mRNA splicing (AS) provides the potential to produce diversity at RNA and protein levels. Disruptions in the regulation of pre-mRNA splicing can lead to diseases. With the development of transcriptome and genome sequencing technology, increasing diseases have been identified to be associated with abnormal splicing of mRNAs. In tumors, abnormal alternative splicing frequently plays critical roles in cancer pathogenesis and may be considered as new biomarkers and therapeutic targets for cancer intervention. Metabolic abnormalities and immune disorders are important hallmarks of cancer. AS produces multiple different isoforms and diversifies protein expression, which is utilized by the immune and metabolic reprogramming systems to expand gene functions. The abnormal splicing events contributed to tumor progression, partially due to effects on immune response and metabolic reprogramming. Herein, we reviewed the vital role of alternative splicing in regulating cancer metabolism and immune response. We discussed how alternative splicing regulates metabolic reprogramming of cancer cells and antitumor immune response, and the possible strategies to targeting alternative splicing pathways or splicing-regulated metabolic pathway in the context of anticancer immunotherapy. Further, we highlighted the challenges and discuss the perspectives for RNA-based strategies for the treatment of cancer with abnormally alternative splicing isoforms.

The function of prohibitins in mitochondria and the clinical potentials.

Prohibitins (PHBs) are a class of highly evolutionarily conserved proteins that widely distribute in prokaryotes and eukaryotes. PHBs function in cell growth and proliferation or differentiation, regulating metabolism and signaling pathways. PHBs have different subcellular localization in eukaryotes, but they are mainly located in mitochondria. In the mitochondria, PHBs stabilize the structure of the mitochondrial membrane and regulate mitochondrial autophagy, mitochondrial dynamics, mitochondrial biogenesis and quality control, and mitochondrial unfolded protein response. PHBs has shown to be associated with many diseases, such as mitochondria diseases, cancers, infectious diseases, and so on. Some molecule targets of PHBs can interfere with the occurrence and development of diseases. Therefore, this review clarifies the functions of PHBs in mitochondria, and provides a summary of the potential values in clinics.

The cancer metabolic reprogramming and immune response.

The overlapping metabolic reprogramming of cancer and immune cells is a putative determinant of the antitumor immune response in cancer. Increased evidence suggests that cancer metabolism not only plays a crucial role in cancer signaling for sustaining tumorigenesis and survival, but also has wider implications in the regulation of antitumor immune response through both the release of metabolites and affecting the expression of immune molecules, such as lactate, PGE2, arginine, etc. Actually, this energetic interplay between tumor and immune cells leads to metabolic competition in the tumor ecosystem, limiting nutrient availability and leading to microenvironmental acidosis, which hinders immune cell function. More interestingly, metabolic reprogramming is also indispensable in the process of maintaining self and body homeostasis by various types of immune cells. At present, more and more studies pointed out that immune cell would undergo metabolic reprogramming during the process of proliferation, differentiation, and execution of effector functions, which is essential to the immune response. Herein, we discuss how metabolic reprogramming of cancer cells and immune cells regulate antitumor immune response and the possible approaches to targeting metabolic pathways in the context of anticancer immunotherapy. We also describe hypothetical combination treatments between immunotherapy and metabolic intervening that could be used to better unleash the potential of anticancer therapies.

PARP inhibitor resistance: the underlying mechanisms and clinical implications.

Due to the DNA repair defect, BRCA1/2 deficient tumor cells are more sensitive to PARP inhibitors (PARPi) through the mechanism of synthetic lethality. At present, several PAPRi targeting poly (ADP-ribose) polymerase (PARP) have been approved for ovarian cancer and breast cancer indications. However, PARPi resistance is ubiquitous in clinic. More than 40% BRCA1/2-deficient patients fail to respond to PARPi. In addition, lots of patients acquire PARPi resistance with prolonged oral administration of PARPi. Homologous recombination repair deficient (HRD), as an essential prerequisite of synthetic lethality, plays a vital role in killing tumor cells. Therefore, Homologous recombination repair restoration (HRR) becomes the predominant reason of PARPi resistance. Recently, it was reported that DNA replication fork protection also contributed to PARPi resistance in BRCA1/2-deficient cells and patients. Moreover, various factors, such as reversion mutations, epigenetic modification, restoration of ADP-ribosylation (PARylation) and pharmacological alteration lead to PARPi resistance as well. In this review, we reviewed the underlying mechanisms of PARP inhibitor resistance in detail and summarized the potential strategies to overcome PARPi resistance and increase PARPi sensitivity.

Age-related common miRNA polymorphism associated with severe toxicity in lung cancer patients treated with platinum-based chemotherapy.

Platinum-based chemotherapy toxicity severely impedes successful treatment in lung cancer patients. MicroRNAs (miRs) have a significant impact on the occurrence and survival rate of lung cancer. The purpose of this study was to investigate the association between common miRNA variants and platinum-based chemotherapy toxicity in lung cancer patients. A total of eight functional single nucleotide polymorphisms (SNPs) of miRNA were genotyped in 408 lung cancer patients by MALDI-TOF mass spectrometry. All the patients were histologically confirmed as lung cancer, and were treated with platinum-based chemotherapy for at least two cycles. It was found that the polymorphism rs2042553 of miR-5197 had a significant association with overall severe toxicity in both additive (P=.031, odds ratio [OR]=1.41, 95% confidence interval [CI] 1.03-1.93) and dominant (P=.009, OR=1.80, 95% CI 1.16-2.80) models. MiR-605 rs2043556 was significantly related to severe hepatotoxicity in dominant model (P=.022, OR=2.51, 95% CI 1.12-4.14). In addition, rs2910164 of miR-146a had marginal statistical effect on severe hepatotoxicity in additive model (P=.054). The subgroup analyses showed that miR-27a rs895819 was related to gastrointestinal toxicity in age >56 years old, smoking and non-smoking patients. Taken together, our results revealed that polymorphisms of miR-5197, miR-605, miR-146a, and miR-27a contributed to the chemotherapy toxicity of lung cancer, which may serve as a predictive tool for toxicity evaluation of platinum-based chemotherapy in lung cancer patients.

Expression of REST4 in human gliomas in vivo and influence of pioglitazone on REST in vitro.

The repressor element-1 (RE1) silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) has an irreplaceable role during the differentiation of neurons. REST has multiple splice variants which link to various types of cancer. Previous work had highlighted the role of REST in glioma, where the expression of REST is enhanced. But whether alternative splicing of REST is expressed in glioma has not been described. Here, we show that a specific isoform REST4 is expressed in glioma specimens, and will influence the mRNA level of REST in vivo. Peroxisome proliferator-activated receptor-γ (PPARγ) agonists have a role of antineoplastic in various tumor cells, which including glioma cells. Moreover, study indicated that PPARγ agonist pioglitazone can promote alternative splicing of REST pre-mRNA. In this study, we selected pioglitazone as a tool drug to explore whether the role of pioglitazone in anti-glioma is mediated by regulating REST expression or promoting alternative splicing of REST in glioma cells. Results show that pioglitazone can inhibit proliferation and induce apoptosis of glioma cell in vitro, which may be mediated by down-regulating REST mRNA level but not by inducing alternative splicing of REST pre-mRNA. Our study firstly reports the expression of REST4 in glioma tissue samples. And we recommend that pioglitazone, which can reduce the expression level of REST, represents a promising drug for therapy of glioma.

MicroRNA-184 acts as a potential diagnostic and prognostic marker in epithelial ovarian cancer and regulates cell proliferation, apoptosis and inflammation.

MicroRNA-184 (miR-184) is found to be significantly deregulated in human cancers associated with tumorigenesis and progression. In this study, we aimed to investigate the role and mechanism of miR-184 expression in epithelial ovarian cancer (EOC). Relative expression of miR-184 was measured by quantificational real-time polymerase chain reaction assay (qRT-PCR) in 80 EOC patients. Kaplan-Meier curve and the log-rank test were conducted to detect the prognostic value of miR-184. Function assays including cell proliferation, apoptosis and inflammation were further explored in vitro. We found that miR-184 was down-regulated in EOC tissues and cell lines compared with paired non-cancerous tissues and IOSE, respectively. Moreover, miR-184 was expressed at significantly lower levels in late-stage (III/IV) EOC tissues. Cox regression multivariate analysis indicated that miR-184 and FIGO stage were independent prognostic indicators for EOC patients. Patients with high miR-184 level achieved significantly a higher 5-year survival rate compared with low level group (P < 0.001). Functional assays showed that miR-184 over-expression could suppress EOC cell proliferation as well as inflammation and induce apoptosis in vitro. Altogether, our results suggest that miR-184 together with pathologic diagnosis is critical for prognosis determination in EOC patients and help select treatment strategy.

Mendelian Randomization Study Supports Genetic Liability to Obsessive-Compulsive Disorder Associated With the Risk of Alzheimer's Disease.

BACKGROUND: Observational studies have suggested that obsessive-compulsive disorder (OCD) may be associated with Alzheimer's disease (AD). However, whether OCD is a causal risk factor for AD remains unclear. This study aimed to assess the causal effect of OCD on AD risk by performing a two-sample Mendelian randomization (MR) analysis. METHODS: Genome-wide association summary statistics were obtained for OCD, comprising 2688 cases and 7037 controls, as well as for AD, including 21,982 cases and 41,944 controls from Kunkle et al.'s study, and 39,918 cases and 358,140 controls from Wightman et al.'s study. On the basis of two diverse thresholds, OCD-associated genetic variants were screened as instrumental variables (IVs) for subsequent MR analyses. Inverse variance weighed was the primary MR method. MR-Egger, weighted median, and weighted mode were used as supplementary MR methods. Various sensitivity tests assessed the reliability of MR results. RESULTS: On the basis of strict IV selecting thresholds, inverse-variance weighted (IVW) identified significant causal associations between genetic liability to OCD and increased risk of AD in two different sources ((i) Kunkle et al.: odds ratio [OR] = 1.070, 95% confidence interval [CI]: 1.015-1.127, p = 0.012; (ii) Wightman et al. 0.012; (iii) Wightman et al.: OR = 1.051, 95% CI: 1.014-1.090, p = 0.007). Three other supplementary MR methods yielded similar results to IVWs (OR > 1). Furthermore, all results were replicated in MR analyses based on lenient IV selecting thresholds. The sensitivity tests indicated that MR results were stable and not affected by significant horizontal pleiotropy. CONCLUSIONS: This comprehensive MR study suggests that genetic liability to OCD is a causal risk factor for AD. Early intervention in patients with OCD may be beneficial in preventing future AD progression.

Predicting progression-free survival in patients with epithelial ovarian cancer using an interpretable random forest model.

Prognostic models play a crucial role in providing personalised risk assessment, guiding treatment decisions, and facilitating the counselling of patients with cancer. However, previous imaging-based artificial intelligence models of epithelial ovarian cancer lacked interpretability. In this study, we aimed to develop an interpretable machine-learning model to predict progression-free survival in patients with epithelial ovarian cancer using clinical variables and radiomics features. A total of 102 patients with epithelial ovarian cancer who underwent contrast-enhanced computed tomography scans were enrolled in this retrospective study. Pre-surgery clinical data, including age, performance status, body mass index, tumour stage, venous blood cancer antigen-125 (CA125) level, white blood cell count, neutrophil count, red blood cell count, haemoglobin level, and platelet count, were obtained from medical records. The volume of interest for each tumour was manually delineated slice-by-slice along the boundary. A total of 2074 radiomic features were extracted from the pre- and post-contrast computed tomography images. Optimal radiomic features were selected using the Least Absolute Shrinkage and Selection Operator logistic regression. Multivariate Cox analysis was performed to identify independent predictors of three-year progression-free survival. The random forest algorithm developed radiomic and combined models using four-fold cross-validation. Finally, the Shapley additive explanation algorithm was applied to interpret the predictions of the combined model. Multivariate Cox analysis identified CA-125 levels (P = 0.015), tumour stage (P = 0.019), and Radscore (P < 0.001) as independent predictors of progression-free survival. The combined model based on these factors achieved an area under the curve of 0.812 (95 % confidence interval: 0.802-0.822) in the training cohort and 0.772 (95 % confidence interval: 0.727-0.817) in the validation cohort. The most impactful features on the model output were Radscore, followed by tumour stage and CA-125. In conclusion, the Shapley additive explanation-based interpretation of the prognostic model enables clinicians to understand the reasoning behind predictions better.

Diallyl disulfide induces DNA damage and growth inhibition in colorectal cancer cells by promoting POU2F1 ubiquitination.

Previous studies have demonstrated that diallyl disulfide (DADS) exhibits potent anti-tumor activity. However, the pharmacological actions of DADS in inhibiting the growth of colorectal cancer (CRC) cells have not been clarified. Herein, we show that DADS treatment impairs the activation of the pentose phosphate pathway (PPP) to decrease PRPP (5-phosphate ribose-1-pyrophosphate) production, enhancing DNA damage and cell apoptosis, and inhibiting the growth of CRC cells. Mechanistically, DADS treatment promoted POU2F1 K48-linked ubiquitination and degradation by attenuating the PI3K/AKT signaling to up-regulate TRIM21 expression in CRC cells. Evidently, TRIM21 interacted with POU2F1, and induced the K272 ubiquitination of POU2F1. The effects of DADS on the enhanced K272 ubiquitination of POU2F1, the PPP flux, PRPP production, DNA damage and cell apoptosis as well as the growth of CRC tumors in vivo were significantly mitigated by TRIM21 silencing or activating the PI3K signaling in CRC cells. Conversely, the effects of DADS were enhanced by TRIM21 over-expression or inhibiting the PI3K/AKT signaling in CRC cells. Collectively, our findings reveal a novel mechanism by which DADS suppresses the growth of CRC by promoting POU2F1 ubiquitination, and may aid in design of novel therapeutic intervention of CRC.

HPV E6/E7: insights into their regulatory role and mechanism in signaling pathways in HPV-associated tumor.

Human papillomavirus (HPV) is a class of envelope-free double-stranded DNA virus. HPV infection has been strongly associated with the development of many malignancies, such as cervical, anal and oral cancers. The viral oncoproteins E6 and E7 perform central roles on HPV-induced carcinogenic processes. During tumor development, it usually goes along with the activation of abnormal signaling pathways. E6 and E7 induces changes in cell cycle, proliferation, invasion, metastasis and other biological behaviors by affecting downstream tumor-related signaling pathways, thus promoting malignant transformation of cells and ultimately leading to tumorigenesis and progression. Here, we summarized that E6 and E7 proteins promote HPV-associated tumorigenesis and development by regulating the activation of various tumor-related signaling pathways, for example, the Wnt/ß-catenin, PI3K/Akt, and NF-kB signaling pathway. We also discussed the importance of HPV-encoded E6 and E7 and their regulated tumor-related signaling pathways for the diagnosis and effective treatment of HPV-associated tumors.

Cellular metabolism: A key player in cancer ferroptosis.

Cellular metabolism is the fundamental process by which cells maintain growth and self-renewal. It produces energy, furnishes raw materials, and intermediates for biomolecule synthesis, and modulates enzyme activity to sustain normal cellular functions. Cellular metabolism is the foundation of cellular life processes and plays a regulatory role in various biological functions, including programmed cell death. Ferroptosis is a recently discovered form of iron-dependent programmed cell death. The inhibition of ferroptosis plays a crucial role in tumorigenesis and tumor progression. However, the role of cellular metabolism, particularly glucose and amino acid metabolism, in cancer ferroptosis is not well understood. Here, we reviewed glucose, lipid, amino acid, iron and selenium metabolism involvement in cancer cell ferroptosis to elucidate the impact of different metabolic pathways on this process. Additionally, we provided a detailed overview of agents used to induce cancer ferroptosis. We explained that the metabolism of tumor cells plays a crucial role in maintaining intracellular redox homeostasis and that disrupting the normal metabolic processes in these cells renders them more susceptible to iron-induced cell death, resulting in enhanced tumor cell killing. The combination of ferroptosis inducers and cellular metabolism inhibitors may be a novel approach to future cancer therapy and an important strategy to advance the development of treatments.

Altered glycosylation in cancer: molecular functions and therapeutic potential.

Glycosylation, a key mode of protein modification in living organisms, is critical in regulating various biological functions by influencing protein folding, transportation, and localization. Changes in glycosylation patterns are a significant feature of cancer, are associated with a range of pathological activities in cancer-related processes, and serve as critical biomarkers providing new targets for cancer diagnosis and treatment. Glycoproteins like human epidermal growth factor receptor 2 (HER2) for breast cancer, alpha-fetoprotein (AFP) for liver cancer, carcinoembryonic antigen (CEA) for colon cancer, and prostate-specific antigen (PSA) for prostate cancer are all tumor biomarkers approved for clinical use. Here, we introduce the diversity of glycosylation structures and newly discovered glycosylation substrate-glycosylated RNA (glycoRNA). This article focuses primarily on tumor metastasis, immune evasion, metabolic reprogramming, aberrant ferroptosis responses, and cellular senescence to illustrate the role of glycosylation in cancer. Additionally, we summarize the clinical applications of protein glycosylation in cancer diagnostics, treatment, and multidrug resistance. We envision a promising future for the clinical applications of protein glycosylation.

Progesterone Enhances Niraparib Efficacy in Ovarian Cancer by Promoting Palmitoleic-Acid-Mediated Ferroptosis.

Poly (adenosine 5'-diphosphate-ribose) polymerase inhibitors (PARPi) are increasingly important in the treatment of ovarian cancer. However, more than 40% of BRCA1/2-deficient patients do not respond to PARPi, and BRCA wild-type cases do not show obvious benefit. In this study, we demonstrated that progesterone acted synergistically with niraparib in ovarian cancer cells by enhancing niraparib-mediated DNA damage and death regardless of BRCA status. This synergy was validated in an ovarian cancer organoid model and in vivo experiments. Furthermore, we found that progesterone enhances the activity of niraparib in ovarian cancer through inducing ferroptosis by up-regulating palmitoleic acid and causing mitochondrial damage. In clinical cohort, it was observed that progesterone prolonged the survival of patients with ovarian cancer receiving PARPi as second-line maintenance therapy, and high progesterone receptor expression combined with low glutathione peroxidase 4 (GPX4) expression predicted better efficacy of PARPi in patients with ovarian cancer. These findings not only offer new therapeutic strategies for PARPi poor response ovarian cancer but also provide potential molecular markers for predicting the PARPi efficacy.