Stress-triggered hematopoietic stem cell proliferation relies on PrimPol-mediated repriming.

Stem cell division is linked to tumorigenesis by yet-elusive mechanisms. The hematopoietic system reacts to stress by triggering hematopoietic stem and progenitor cell (HSPC) proliferation, which can be accompanied by chromosomal breakage in activated hematopoietic stem cells (HSCs). However, whether these lesions persist in their downstream progeny and induce a canonical DNA damage response (DDR) remains unclear. Inducing HSPC proliferation by simulated viral infection, we report that the associated DNA damage is restricted to HSCs and that proliferating HSCs rewire their DDR upon endogenous and clastogen-induced damage. Combining transcriptomics, single-cell and single-molecule assays on murine bone marrow cells, we found accelerated fork progression in stimulated HSPCs, reflecting engagement of PrimPol-dependent repriming, at the expense of replication fork reversal. Ultimately, competitive bone marrow transplantation revealed the requirement of PrimPol for efficient HSC amplification and bone marrow reconstitution. Hence, fine-tuning replication fork plasticity is essential to support stem cell functionality upon proliferation stimuli.

RHOJ controls EMT-associated resistance to chemotherapy.

The resistance of cancer cells to therapy is responsible for the death of most patients with cancer1. Epithelial-to-mesenchymal transition (EMT) has been associated with resistance to therapy in different cancer cells2,3. However, the mechanisms by which EMT mediates resistance to therapy remain poorly understood. Here, using a mouse model of skin squamous cell carcinoma undergoing spontaneous EMT during tumorigenesis, we found that EMT tumour cells are highly resistant to a wide range of anti-cancer therapies both in vivo and in vitro. Using gain and loss of function studies in vitro and in vivo, we found that RHOJ-a small GTPase that is preferentially expressed in EMT cancer cells-controls resistance to therapy. Using genome-wide transcriptomic and proteomic profiling, we found that RHOJ regulates EMT-associated resistance to chemotherapy by enhancing the response to replicative stress and activating the DNA-damage response, enabling tumour cells to rapidly repair DNA lesions induced by chemotherapy. RHOJ interacts with proteins that regulate nuclear actin, and inhibition of actin polymerization sensitizes EMT tumour cells to chemotherapy-induced cell death in a RHOJ-dependent manner. Together, our study uncovers the role and the mechanisms through which RHOJ acts as a key regulator of EMT-associated resistance to chemotherapy.

RAD51 restricts DNA over-replication from re-activated origins.

Eukaryotic cells rely on several mechanisms to ensure that the genome is duplicated precisely once in each cell division cycle, preventing DNA over-replication and genomic instability. Most of these mechanisms limit the activity of origin licensing proteins to prevent the reactivation of origins that have already been used. Here, we have investigated whether additional controls restrict the extension of re-replicated DNA in the event of origin re-activation. In a genetic screening in cells forced to re-activate origins, we found that re-replication is limited by RAD51 and enhanced by FBH1, a RAD51 antagonist. In the presence of chromatin-bound RAD51, forks stemming from re-fired origins are slowed down, leading to frequent events of fork reversal. Eventual re-initiation of DNA synthesis mediated by PRIMPOL creates ssDNA gaps that facilitate the partial elimination of re-duplicated DNA by MRE11 exonuclease. In the absence of RAD51, these controls are abrogated and re-replication forks progress much longer than in normal conditions. Our study uncovers a safeguard mechanism to protect genome stability in the event of origin reactivation.

PRIMPOL-Mediated Adaptive Response Suppresses Replication Fork Reversal in BRCA-Deficient Cells.

Acute treatment with replication-stalling chemotherapeutics causes reversal of replication forks. BRCA proteins protect reversed forks from nucleolytic degradation, and their loss leads to chemosensitivity. Here, we show that fork degradation is no longer detectable in BRCA1-deficient cancer cells exposed to multiple cisplatin doses, mimicking a clinical treatment regimen. This effect depends on increased expression and chromatin loading of PRIMPOL and is regulated by ATR activity. Electron microscopy and single-molecule DNA fiber analyses reveal that PRIMPOL rescues fork degradation by reinitiating DNA synthesis past DNA lesions. PRIMPOL repriming leads to accumulation of ssDNA gaps while suppressing fork reversal. We propose that cells adapt to repeated cisplatin doses by activating PRIMPOL repriming under conditions that would otherwise promote pathological reversed fork degradation. This effect is generalizable to other conditions of impaired fork reversal (e.g., SMARCAL1 loss or PARP inhibition) and suggests a new strategy to modulate cisplatin chemosensitivity by targeting the PRIMPOL pathway.

PrimPol-mediated repriming facilitates replication traverse of DNA interstrand crosslinks.

DNA interstrand crosslinks (ICLs) induced by endogenous aldehydes or chemotherapeutic agents interfere with essential processes such as replication and transcription. ICL recognition and repair by the Fanconi Anemia pathway require the formation of an X-shaped DNA structure that may arise from convergence of two replication forks at the crosslink or traversing of the lesion by a single replication fork. Here, we report that ICL traverse strictly requires DNA repriming events downstream of the lesion, which are carried out by PrimPol, the second primase-polymerase identified in mammalian cells after Polα/Primase. The recruitment of PrimPol to the vicinity of ICLs depends on its interaction with RPA, but not on FANCM translocase or the BLM/TOP3A/RMI1-2 (BTR) complex that also participate in ICL traverse. Genetic ablation of PRIMPOL makes cells more dependent on the fork convergence mechanism to initiate ICL repair, and PRIMPOL KO cells and mice display hypersensitivity to ICL-inducing drugs. These results open the possibility of targeting PrimPol activity to enhance the efficacy of chemotherapy based on DNA crosslinking agents.

Development of convolutional neural network models that recognize normal anatomic structures during real-time radial-array and linear-array EUS (with videos).

BACKGROUND AND AIMS: EUS is a high-skill technique that requires numerous procedures to achieve competence. However, training facilities are limited worldwide. Convolutional neural network (CNN) models have been previously implemented for object detection. We developed 2 EUS-based CNN models for normal anatomic structure recognition during real-time linear- and radial-array EUS evaluations. METHODS: The study was performed from February 2020 to June 2022. Consecutive patient videos of linear- and radial-array EUS videos were recorded. Expert endosonographers identified and labeled 20 normal anatomic structures within the videos for training and validation of the CNN models. Initial CNN models (CNNv1) were developed from 45 videos and the improved models (CNNv2) from an additional 102 videos. CNN model performance was compared with that of 2 expert endosonographers. RESULTS: CNNv1 used 45,034 linear-array EUS frames and 21,063 radial-array EUS frames. CNNv2 used 148,980 linear-array EUS frames and 128,871 radial-array EUS frames. Linear-array CNNv1 and radial-array CNNv1 achieved a 75.65% and 71.36% mean average precision (mAP) with a total loss of .19 and .18, respectively. Linear-array CNNv2 obtained an 88.7% mAP with a .06 total loss, whereas radial-array CNNv2 achieved an 83.5% mAP with a .07 total loss. CNNv2 accurately detected all studied normal anatomic structures with a >98% observed agreement during clinical validation. CONCLUSIONS: The proposed CNN models accurately recognize the normal anatomic structures in prerecorded videos and real-time EUS. Prospective trials are needed to evaluate the impact of these models on the learning curves of EUS trainees.

POLD3 Is Haploinsufficient for DNA Replication in Mice.

The Pold3 gene encodes a subunit of the Polδ DNA polymerase complex. Pold3 orthologs are not essential in Saccharomyces cerevisiae or chicken DT40 cells, but the Schizosaccharomyces pombe ortholog is essential. POLD3 also has a specialized role in the repair of broken replication forks, suggesting that POLD3 activity could be particularly relevant for cancer cells enduring high levels of DNA replication stress. We report here that POLD3 is essential for mouse development and is also required for viability in adult animals. Strikingly, even Pold3(+/-) mice were born at sub-Mendelian ratios, and, of those born, some presented hydrocephaly and had a reduced lifespan. In cells, POLD3 deficiency led to replication stress and cell death, which were aggravated by the expression of activated oncogenes. Finally, we show that Pold3 deletion destabilizes all members of the Polδ complex, explaining its major role in DNA replication and the severe impact of its deficiency.

3D chromatin connectivity underlies replication origin efficiency in mouse embryonic stem cells.

In mammalian cells, chromosomal replication starts at thousands of origins at which replisomes are assembled. Replicative stress triggers additional initiation events from 'dormant' origins whose genomic distribution and regulation are not well understood. In this study, we have analyzed origin activity in mouse embryonic stem cells in the absence or presence of mild replicative stress induced by aphidicolin, a DNA polymerase inhibitor, or by deregulation of origin licensing factor CDC6. In both cases, we observe that the majority of stress-responsive origins are also active in a small fraction of the cell population in a normal S phase, and stress increases their frequency of activation. In a search for the molecular determinants of origin efficiency, we compared the genetic and epigenetic features of origins displaying different levels of activation, and integrated their genomic positions in three-dimensional chromatin interaction networks derived from high-depth Hi-C and promoter-capture Hi-C data. We report that origin efficiency is directly proportional to the proximity to transcriptional start sites and to the number of contacts established between origin-containing chromatin fragments, supporting the organization of origins in higher-level DNA replication factories.

The Role of ZO-2 in Modulating JAM-A and γ-Actin Junctional Recruitment, Apical Membrane and Tight Junction Tension, and Cell Response to Substrate Stiffness and Topography.

This work analyzes the role of the tight junction (TJ) protein ZO-2 on mechanosensation. We found that the lack of ZO-2 reduced apical membrane rigidity measured with atomic force microscopy, inhibited the association of γ-actin and JAM-A to the cell border, and instead facilitated p114RhoGEF and afadin accumulation at the junction, leading to an enhanced mechanical tension at the TJ measured by FRET, with a ZO-1 tension probe, and increased tricellular TJ tension. Simultaneously, adherens junction tension measured with an E-cadherin probe was unaltered. The stability of JAM-A and ZO-2 binding was assessed by a collaborative in silico study. The absence of ZO-2 also impacted the cell response to the substrate, as monolayers plated in 20 kPa hydrogels developed holes not seen in parental cultures and displayed a retarded elongation and formation of cell aggregates. The absence of ZO-2 was sufficient to induce YAP and Snail nuclear accumulation in cells cultured over glass, but when ZO-2 KD cells were plated in nanostructured ridge arrays, they displayed an increased abundance of nuclear Snail and conspicuous internalization of claudin-4. These results indicate that the absence of ZO-2 also impairs the response of cells to substrate stiffness and exacerbates transformation triggered by substrate topography.

Cortico-thalamocortical interactions for learning, memory and decision-making.

The thalamus and cortex are interconnected both functionally and anatomically and share a common developmental trajectory. Interactions between the mediodorsal thalamus (MD) and different parts of the prefrontal cortex are essential in cognitive processes, such as learning and adaptive decision-making. Cortico-thalamocortical interactions involving other dorsal thalamic nuclei, including the anterior thalamus and pulvinar, also influence these cognitive processes. Our work, and that of others, indicates a crucial influence of these interdependent cortico-thalamocortical neural networks that contributes actively to the processing of information within the cortex. Each of these thalamic nuclei also receives potent subcortical inputs that are likely to provide additional influences on their regulation of cortical activity. Here, we highlight our current neuroscientific research aimed at establishing when cortico-MD thalamocortical neural network communication is vital within the context of a rapid learning and memory discrimination task. We are collecting evidence of MD-prefrontal cortex neural network communication in awake, behaving male rhesus macaques. Given the prevailing evidence, further studies are needed to identify both broad and specific mechanisms that govern how the MD, anterior thalamus and pulvinar cortico-thalamocortical interactions support learning, memory and decision-making. Current evidence shows that the MD (and the anterior thalamus) are crucial for frontotemporal communication, and the pulvinar is crucial for frontoparietal communication. Such work is crucial to advance our understanding of the neuroanatomical and physiological bases of these brain functions in humans. In turn, this might offer avenues to develop effective treatment strategies to improve the cognitive deficits often observed in many debilitating neurological disorders and diseases and in neurodegeneration.

Artificial intelligence for diagnosing neoplasia on digital cholangioscopy: development and multicenter validation of a convolutional neural network model.

BACKGROUND: We aimed to develop a convolutional neural network (CNN) model for detecting neoplastic lesions during real-time digital single-operator cholangioscopy (DSOC) and to clinically validate the model through comparisons with DSOC expert and nonexpert endoscopists. METHODS: In this two-stage study, we first developed and validated CNN1. Then, we performed a multicenter diagnostic trial to compare four DSOC experts and nonexperts against an improved model (CNN2). Lesions were classified into neoplastic and non-neoplastic in accordance with Carlos Robles-Medranda (CRM) and Mendoza disaggregated criteria. The final diagnosis of neoplasia was based on histopathology and 12-month follow-up outcomes. RESULTS: In stage I, CNN2 achieved a mean average precision of 0.88, an intersection over the union value of 83.24 %, and a total loss of 0.0975. For clinical validation, a total of 170 videos from newly included patients were analyzed with the CNN2. Half of cases (50 %) had neoplastic lesions. This model achieved significant accuracy values for neoplastic diagnosis, with a 90.5 % sensitivity, 68.2 % specificity, and 74.0 % and 87.8 % positive and negative predictive values, respectively. The CNN2 model outperformed nonexpert #2 (area under the receiver operating characteristic curve [AUC]-CRM 0.657 vs. AUC-CNN2 0.794, P < 0.05; AUC-Mendoza 0.582 vs. AUC-CNN2 0.794, P < 0.05), nonexpert #4 (AUC-CRM 0.683 vs. AUC-CNN2 0.791, P < 0.05), and expert #4 (AUC-CRM 0.755 vs. AUC-CNN2 0.848, P < 0.05; AUC-Mendoza 0.753 vs. AUC-CNN2 0.848, P < 0.05). CONCLUSIONS: The proposed CNN model distinguished neoplastic bile duct lesions with good accuracy and outperformed two nonexpert and one expert endoscopist.

Retraction: Oncogenic activity of Cdc6 through repression of the INK4/ARF locus.

This corrects the article DOI: 10.1038/nature04585.

Sequence analysis of SWEET transporters from trypanosomatids and evaluation of its expression in Trypanosoma cruzi.

Trypanosoma cruzi is an obligate parasite that uses glucose as one of the main resources to maintain its survival and proliferation. In eukaryotic cells glucose transport across membranes is mediated by facilitated transport through a variety of transporters. Herein, genes from the recently described SWEET family of carbohydrate transporters were identified in trypanosomatid parasites, including the medically important species T. cruzi and Leishmania spp. The identified genes have sequences with the typical attributes of known SWEET transporters. The expression of TcSWEET, the gene for the SWEET transporter found in the T. cruzi genome, was evidenced by immunohistochemistry using a polyclonal serum raised against peptides selected from the deduced TcSWEET protein sequence. In Western blot analysis, this α-TcSWEET serum detected proteins within the theoretical molecular mass for TcSWEET (25.8 kDa) in total epimastigote lysates, suggesting its expression at this parasite stage. Additionally, this serum stained epimastigotes at localizations consistent with the cell body and the flagellum. Together, these data suggests that SWEET transporters may contribute to glucose transport in trypanosomatid parasites.

Motif WFYY of human PrimPol is crucial to stabilize the incoming 3'-nucleotide during replication fork restart.

PrimPol is the second primase in human cells, the first with the ability to start DNA chains with dNTPs. PrimPol contributes to DNA damage tolerance by restarting DNA synthesis beyond stalling lesions, acting as a TLS primase. Multiple alignment of eukaryotic PrimPols allowed us to identify a highly conserved motif, WxxY near the invariant motif A, which contains two active site metal ligands in all members of the archeo-eukaryotic primase (AEP) superfamily. In vivo and in vitro analysis of single variants of the WFYY motif of human PrimPol demonstrated that the invariant Trp87 and Tyr90 residues are essential for both primase and polymerase activities, mainly due to their crucial role in binding incoming nucleotides. Accordingly, the human variant F88L, altering the WFYY motif, displayed reduced binding of incoming nucleotides, affecting its primase/polymerase activities especially during TLS reactions on UV-damaged DNA. Conversely, the Y89D mutation initially associated with High Myopia did not affect the ability to rescue stalled replication forks in human cells. Collectively, our data suggest that the WFYY motif has a fundamental role in stabilizing the incoming 3'-nucleotide, an essential requisite for both its primase and TLS abilities during replication fork restart.

Consenso de expertos sobre la eficacia clínica y directrices sobre la terapia de oxígeno transdérmico continuo para la cicatrización de las heridas complejas o difíciles de cicatrizar.

INTRODUCTION: Oxygen is pivotal for wound healing. Its lack or hypoxia can delay this process, especially in individuals with comorbidities, potentially resulting in complex or hard-to-heal wounds. The Colombian Association of Diabetes (ACD) and the Colombian Association of Internal Medicine (ACMI) collaborated with a diverse group of experts to provide recommendations on the efficacy and best practices of continuous transdermal oxygen therapy (TOTc) in the care of such wounds. METHOD: A modified Delphi technique was employed to obtain controlled feedback and responses. Experts from various disciplines engaged in reviewing and discussing numerous relevant scientific studies, focusing on the role of TOTc in treating chronic ulcers. RESULTS: Continuous transdermal oxygen therapy has proven to be an effective and safe treatment for chronic and/or hard-to-heal ulcers. This therapy directly addresses the wound's oxygen deficiency, providing an environment conducive to healing. Significant benefits were observed, including the acceleration of the healing process, wound size reduction, and an enhancement in patient quality of life. Its efficacy was found across various ulcer etiologies, underscoring its therapeutic versatility. CONCLUSIONS: Continuous transdermal oxygen therapy is effective and safe for treating chronic and hard-to-heal ulcers. It's crucial to address each case individually and through a multidisciplinary approach to maximize this therapy's benefits. Both evidence and clinical experience back its utility across a variety of ulcer etiologies.

RESUMEN: Introducción: El oxígeno es esencial en la cicatrización de heridas. Su ausencia o hipoxia puede retrasar este proceso, especialmente en individuos con comorbilidades, lo que podría resultar en heridas complejas o de difícil cicatrización. La Asociación Colombiana de Diabetes (ACD) y la Asociación Colombiana de Medicina Interna (ACMI) se unieron con un grupo diverso de expertos para brindar recomendaciones sobre la eficacia y práctica de la terapia de oxígeno transdérmico continuo (TOTc) en el cuidado de estas heridas. Método: Se utilizó la técnica Delphi modificada para obtener respuestas y retroalimentación controlada. Expertos de diversas disciplinas participaron en la revisión y discusión de numerosos estudios científicos relevantes, centrados en el papel de la TOTc en el tratamiento de úlceras crónicas. Resultados: El oxígeno transdérmico continuo ha demostrado ser una terapia eficaz y segura en el tratamiento de úlceras crónicas y/o de difícil cicatrización. Esta terapia aborda directamente la deficiencia de oxígeno en la herida, proporcionando un entorno propicio para la curación. Se observaron beneficios significativos, incluyendo aceleración del proceso de cicatrización, reducción del tamaño de la herida y mejora en la calidad de vida del paciente. Se encontró eficacia en diversas etiologías de úlceras, subrayando su versatilidad terapéutica. Conclusiones: La terapia de oxígeno transdérmico continuo es eficaz y segura para tratar úlceras crónicas y de difícil cicatrización. Es vital abordar cada caso de manera individualizada y mediante un enfoque multidisciplinario para maximizar los beneficios de esta terapia. La evidencia y experiencia clínica respaldan su utilidad en diversas etiologías de úlceras. Palabras clave: Terapia de oxígeno transdérmico continuo, Oxígeno, Pie diabético, Cicatrización de heridas, Cuidado de heridas, Úlceras vasculares, Lesiones por presión, Hipoxia, Infección.

[Gastrointestinal hemorrhage as an uncommon form of presentation of primary intestinal amyloidosis: case report]. / Hemorragia digestiva como forma de presentación poco usual de amiloidosis intestinal primaria: reporte de caso.

Intestinal amyloidosis is a rare and underdiagnosed systemic disease, which is characterized by the extracellular deposition of proteins that are grouped into amyloid fibers. This entity is rare and is usually a form of presentation in the context of systemic amyloidosis, the diagnosis of which is based on the presence of amyloid in histology. The clinic is usually non-specific; chronic diarrhea, weight loss, abdominal pain and bloating; Gastrointestinal bleeding is a very rare manifestation. The case of a 61-year-old woman with symptoms of weight loss, abdominal distension, nausea, vomiting and long hair is presented. Tomographically, a wall thickening of jejunal loops with contrast uptake was evidenced, a finding that was corroborated by a double-balloon anterograde stereoscopy in which multiple were evidenced. The pathology shows distorted and ulcerated villous architecture with positive histochemistry for Congo Red and LAMBDA (+++) immunohistochemistry. In addition, bone marrow aspirate and bone biopsy compatible with infiltration of Lambda chain monoclonal multiple myeloma were performed. During the hospital stay, the patient developed complications such as chronic malnutrition, recurrent infection and several episodes of intestinal subocclusion; characterized by intestinal pneumatosis; due to multiple episodes of these complications, the patient died. Within clinical practice in gastroenterology, intestinal amyloidosis as part of the differential diagnosis of upper gastrointestinal bleeding is infrequent, so a history of diagnosis of multiple myeloma or other monoclonal gammopathy associated with light chains is crucial for early diagnosis and adequate treatment.

[Inflammatory Bowel Disease in elderly patients: Clinical characteristics and management in a tertiary hospital]. / Enfermedad Inflamatoria Intestinal en el adulto mayor: Características clínicas y manejo en un hospital de referencia.

Inflammatory bowel disease (IBD) in elderly patients is characterized by its clinical variability, different differential diagnoses and therapeutic management. The objective of our investigation is to evaluate the clinical characteristics and management of elderly patients with IBD. We developed an observational, descriptive, retrospective study from January 2011 to December 2019 in patients with IBD at the Gastroenterology Service of Guillermo Almenara Irigoyen National Hospital, Lima-Peru. 55 patients with CD and 107 with UC were evaluated; 45.6% of patients with IBD are older adults. Of these, 28 had CD and 46 UC. Older adults with CD presented predominantly an inflammatory phenotype and colonic location, while extensive and left-sided colitis were the most frequent in UC. Elderly patients had a lower CDAI score (279.8 vs 323.2) and a lower Mayo index (7.1 vs 9.2) in relation to the younger, without significant differences. Regarding treatment, a lower use of azathioprine (2 vs 8, p <0.03) and Anti-TNF (9 vs 18, p <0.01) was observed in the elderly with CD. The need for surgery and the frequency of post-surgical complications were similar between both groups. In conclusion, nearly half of IBD patients are older adults. The colonic location was the most frequent in CD, and in UC extensive and left colitis. We observed a lower use of azathioprine and biological therapy in elderly patients, without significant differences in the use of corticosteroids and aminosalicylates compared to younger people.

Characterization of Structural Changes of Casein Micelles at Different PH Using Microscopy and Spectroscopy Techniques.

This study aimed to evaluate the influence of pH changes on morphometric parameters of casein micelles and a general overview of their conformational structure through microscopy techniques, Raman spectroscopy and multivariate analysis. It was found that casein micelles morphology and protein secondary structure depend strongly upon pH. The changes of arithmetic average roughness (Ra), size, and shape of casein micelles at different pH are properly characterized by atomic force and cryo-transmission electron microscopy. Morphometric changes of casein micelles were correlated correctly with folding and unfolding of casein molecules as evaluated by Raman spectroscopy when the pH was varied. The novelty of this contribution consists in demonstrating that there is a close structure-functionality relationship between the morphometric parameters of proteins and their secondary structure. Knowledge about casein micelles can help improve their use of its diverse applications.

Leptin and its receptor are overexpressed in breast cancer tissue of postmenopausal Mexican-Mestizo women with obesity.

The aim of this study was to investigate the expression of leptin (LEP) and its receptor (LEPR) in breast cancer tissue of postmenopausal women with different body mass indexes (BMI), as well as the relationship of this expression with the rate of recurrence free survival (RFS). Leptin and LEPR expression, determined by immunohistochemistry, were studied in breast cancer tissues of 154 patients. Qualitative and semi-quantitative analysis of protein expression was performed by the H-Score method, through the ImageJ's IHC Profiler software. Kaplan-Meier survival analysis and log-rank statistic were used to estimate RFS differences. Protein expression of LEP, was significantly higher in women with overweight or with obesity, when compared to women with normal BMI (P = 0.032 and P = 0.013, respectively). We also observed a significantly higher expression of LEPR in breast tumor cells of women with obesity (58.8%), when compared to women with normal BMI (32.7%) (P = 0.007). Five-year survival rate, regarding LEPR expression, was 82.4% when positive and 94% when negative (P = 0.024). In the Cox proportional-hazards regression model, LEPR expression represented a risk factor for disease recurrence after adjustment for confounding factors (HR = 4.67; 95% CI: 1.13-19.31; P = 0.033). In conclusion, postmenopausal women with obesity and breast cancer present higher LEP and LEPR expression in breast tumors, when compared to women with normal BMI. Independently from BMI, women with tumors LEPR positive have worst RFS, when compared to women with tumors LEPR negative.

PDS5 proteins are required for proper cohesin dynamics and participate in replication fork protection.

Cohesin is a chromatin-bound complex that mediates sister chromatid cohesion and facilitates long-range interactions through DNA looping. How the transcription and replication machineries deal with the presence of cohesin on chromatin remains unclear. The dynamic association of cohesin with chromatin depends on WAPL cohesin release factor (WAPL) and on PDS5 cohesin-associated factor (PDS5), which exists in two versions in vertebrate cells, PDS5A and PDS5B. Using genetic deletion in mouse embryo fibroblasts and a combination of CRISPR-mediated gene editing and RNAi-mediated gene silencing in human cells, here we analyzed the consequences of PDS5 depletion for DNA replication. We found that either PDS5A or PDS5B is sufficient for proper cohesin dynamics and that their simultaneous removal increases cohesin's residence time on chromatin and slows down DNA replication. A similar phenotype was observed in WAPL-depleted cells. Cohesin down-regulation restored normal replication fork rates in PDS5-deficient cells, suggesting that chromatin-bound cohesin hinders the advance of the replisome. We further show that PDS5 proteins are required to recruit WRN helicase-interacting protein 1 (WRNIP1), RAD51 recombinase (RAD51), and BRCA2 DNA repair associated (BRCA2) to stalled forks and that in their absence, nascent DNA strands at unprotected forks are degraded by MRE11 homolog double-strand break repair nuclease (MRE11). These findings indicate that PDS5 proteins participate in replication fork protection and also provide insights into how cohesin and its regulators contribute to the response to replication stress, a common feature of cancer cells.