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This study uncovers a dynamic shift in estrogen receptor expression during granulosa cell (GC) differentiation in the ovary, highlighting a transition from estrogen receptor alpha (ESR1) to estrogen receptor beta (ESR2). Using a transgenic mouse model with Esr1- iCre-mediated Esr2 deletion, we demonstrate that ESR2 expression is absent in GCs derived from ESR1-expressing ovarian surface epithelium (OSE) cells. Single-cell analysis of the OSE-GC lineage reveals a developmental trajectory from Esr1 -expressing OSE cells to Foxl2 -expressing pre-GCs, culminating in GCs exclusively expressing Esr2. Transcriptome analyses identified vasculature-derived TGFβ1 ligands as key regulators of this transition. Supporting this, TGFβ1 treatment of cultured embryonic ovaries reduced Esr1 expression while promoting Esr2 expression. This study underscores the capability of GCs to switch from ESR1 to ESR2 expression as a fundamental aspect of normal differentiation. [ABSTRACT FROM AUTHOR] more...

Background: Pressure injuries are costly and can lead to mortality and psychosocial consequences if not managed effectively. Proper management of pressure injuries is crucial for quality nursing care. However, there is limited research on nurses' knowledge and practices in preventing and managing pressure injuries among critically ill patients in Rwanda. In addition, barriers affecting nurses' practices in this area also need further investigation in order to inform the interventions to improve nursing care of patients with pressure injuries in Rwandan hospitals. Methodology: A cross-sectional study involving 129 health nurses was conducted to determine their knowledge and practice levels regarding the prevention of pressure injuries in critically ill patients, and barriers impeding practice in this area. The research modified the Pieper-Zulkowski Pressure Ulcer Knowledge Test to evaluate the knowledge of nurses concerning the prevention of pressure injuries. A 33-item instrument drawn from pressure ulcer risk assessment and prevention toolkits established by the Agency for Healthcare Research and Quality was used to assess nurses' practices. Additionally, barriers influencing nurses' knowledge and practices related to the prevention of pressure injuries were evaluated through questions derived from a comparable study conducted in Ethiopia. Descriptive statistics were computed for each variable. Mean scores were computed to categorize nurses' level of knowledge and practice. Logistic regression analysis was employed to examine the influence of sociodemographic factors and training on the nurses' knowledge and practice, with a statistical significance set at a p-value less than 0.05. Results: The study found that 40.0% of nurses had inadequate knowledge towards pressure injury prevention, and 60.0% reported that they inadequately practiced pressure injury prevention among critically ill patients. Nurses who have not been trained in pressure injury prevention have a 52.4% reduction in the odd of having adequate practice compared to those who have been trained (OR 0.476; 95% CI 0.211–0.996). Heavy workload, inadequate staff, shortage of equipments, presence of other priorities than pressure injury prevention, inadequate training coverage of pressure injury prevention were the most prevalent barriers reported. Conclusion: The evaluation of nurses' knowledge and practices on pressure injury prevention in critically ill patients at the study setting found that while nurses have satisfactory knowledge, their practical application is lacking due to factors like high workloads and insufficient staffing. The study recommends caution in interpreting the results due to a limited sample size, suggesting further research to guide improvements in nursing practices. [ABSTRACT FROM AUTHOR] more...

Testicular germ cell tumors (TGCTs) are aggressive but sensitive to cisplatin‐based chemotherapy. Alternative therapies are needed for tumors refractory to cisplatin with hypomethylating agents providing one possibility. The mechanisms of cisplatin hypersensitivity and resistance in TGCTs remain poorly understood. Recently, it has been shown that TGCTs, even those resistant to cisplatin, are hypersensitive to very low doses of hypomethylating agents including 5‐aza deoxy‐cytosine (5‐aza) and guadecitabine. We undertook a pharmacogenomic approach in order to better understand mechanisms of TGCT hypomethylating agent hypersensitivity by generating a panel of acquired 5‐aza‐resistant TGCT cells and contrasting these to previously generated acquired isogenic cisplatin‐resistant cells from the same parent. Interestingly, there was a reciprocal relationship between cisplatin and 5‐aza sensitivity, with cisplatin resistance associated with increased sensitivity to 5‐aza and 5‐aza resistance associated with increased sensitivity to cisplatin. Unbiased transcriptome analysis revealed 5‐aza‐resistant cells strongly downregulated polycomb target gene expression, the exact opposite of the finding for cisplatin‐resistant cells, which upregulated polycomb target genes. This was associated with a dramatic increase in H3K27me3 and decrease in DNMT3B levels in 5‐aza‐resistant cells, the exact opposite changes seen in cisplatin‐resistant cells. Evidence is presented that reciprocal regulation of polycomb and DNMT3B may be initiated by changes in DNMT3B levels as DNMT3B knockdown alone in parental cells resulted in increased expression of H3K27me3, EZH2, and BMI1, conferred 5‐aza resistance and cisplatin sensitization, and mediated genome‐wide repression of polycomb target gene expression. Finally, genome‐wide analysis revealed that 5‐aza‐resistant, cisplatin‐resistant, and DNMT3B‐knockdown cells alter the expression of a common set of polycomb target genes. This study highlights that reciprocal epigenetic changes mediated by DNMT3B and polycomb may be a key driver of the unique cisplatin and 5‐aza hypersensitivity of TGCTs and suggests that distinct epigenetic vulnerabilities may exist for pharmacological targeting of TGCTs. [ABSTRACT FROM AUTHOR] more...

Testicular germ cell tumours (TGCTs) respond well to cisplatin-based therapy. However, cisplatin resistance and poor outcomes do occur. It has been suggested that a shift towards DNA hypermethylation mediates cisplatin resistance in TGCT cells, although there is little direct evidence to support this claim. Here we utilized a series of isogenic cisplatin-resistant cell models and observed a strong association between cisplatin resistance in TGCT cells and a net increase in global CpG and non-CpG DNA methylation spanning regulatory, intergenic, genic and repeat elements. Hypermethylated loci were significantly enriched for repressive DNA segments, CTCF and RAD21 sites and lamina associated domains, suggesting that global nuclear reorganization of chromatin structure occurred in resistant cells. Hypomethylated CpG loci were significantly enriched for EZH2 and SUZ12 binding and H3K27me3 sites. Integrative transcriptome and methylome analyses showed a strong negative correlation between gene promoter and CpG island methylation and gene expression in resistant cells and a weaker positive correlation between gene body methylation and gene expression. A bidirectional shift between gene promoter and gene body DNA methylation occurred within multiple genes that was associated with upregulation of polycomb targets and downregulation of tumour suppressor genes. These data support the hypothesis that global remodelling of DNA methylation is a key factor in mediating cisplatin hypersensitivity and chemoresistance of TGCTs and furthers the rationale for hypomethylation therapy for refractory TGCT patients. [ABSTRACT FROM AUTHOR] more...

Purpose: Germ cell tumors (GCTs) are cured with therapy based on cisplatin, although a clinically significant number of patients are refractory and die of progressive disease. Based on preclinical studies indicating that refractory testicular GCTs are hypersensitive to hypomethylating agents (HMAs), we conducted a phase I trial combining the next‐generation HMA guadecitabine (SGI‐110) with cisplatin in recurrent, cisplatin‐resistant GCT patients. Methods: Patients with metastatic GCTs were treated for five consecutive days with guadecitabine followed by cisplatin on day 8, for a 28‐day cycle for up to six cycles. The primary endpoint was safety and toxicity including dose‐limiting toxicity (DLT) and maximum tolerated dose (MTD). Results: The number of patients enrolled was 14. The majority of patients were heavily pretreated. MTD was determined to be 30 mg/m2 guadecitabine followed by 100 mg/m2 cisplatin. The major DLTs were neutropenia and thrombocytopenia. Three patients had partial responses by RECIST criteria, two of these patients, including one with primary mediastinal disease, completed the study and qualified as complete responses by serum tumor marker criteria with sustained remissions of 5 and 13 months and survival of 16 and 26 months, respectively. The overall response rate was 23%. Three patients also had stable disease indicating a clinical benefit rate of 46%. Conclusions: The combination of guadecitabine and cisplatin was tolerable and demonstrated activity in patients with platinum refractory germ cell cancer. [ABSTRACT FROM AUTHOR] more...

CDK4/6 inhibitors (CDK4/6i) have improved survival of patients with estrogen receptor-positive (ER+) breast cancer. However, patients treated with CDK4/6i eventually develop drug resistance and progress. RB1 loss-of-function alterations confer acquired resistance to CDK4/6i, but the optimal therapy for these patients is unclear. Using a genome-wide CRISPR screen, we identified protein arginine methyltransferase 5 (PRMT5) as a molecular vulnerability in ER+/ RB1 -knockout (RBKO) breast cancer cells. PRMT5 inhibition blocked cell cycle G1-to-S transition independent of RB, thus arresting growth of RBKO cells. Proteomics analysis uncovered fused in sarcoma (FUS) as a downstream effector of PRMT5. Pharmacological inhibition of PRMT5 resulted in dissociation of FUS from RNA polymerase II (Pol II), Ser2 Pol II hyperphosphorylation, and intron retention in genes that promote DNA synthesis. Treatment with the PRMT5i inhibitor pemrametostat and fulvestrant synergistically inhibited growth of ER+/RB-deficient patient-derived xenografts, suggesting dual ER and PRMT5 blockade as a novel therapeutic strategy to treat ER+/RB-deficient breast cancer. more...