Disparate pathways for extrachromosomal DNA biogenesis and genomic DNA repair.

Oncogene amplification on extrachromosomal DNA (ecDNA) is a pervasive driver event in cancer, yet our understanding of how ecDNA forms is limited. Here, we couple a CRISPR-based method for ecDNA induction with extensive characterization of newly formed ecDNA to examine their biogenesis. We find that DNA circularization is efficient, irrespective of 3D genome context, with formation of 800kb, 1 Mb, and 1.8 Mb ecDNAs reaching or exceeding 15%. We show non-homologous end joining and microhomology-mediated end joining both contribute to ecDNA formation, while inhibition of DNA-PKcs and ATM have opposing impacts on ecDNA formation. EcDNA and the corresponding chromosomal excision scar can form at significantly different rates and respond differently to DNA-PKcs and ATM inhibition. Taken together, our results support a model of ecDNA formation in which double strand break ends dissociate from their legitimate ligation partners prior to joining of illegitimate ends to form the ecDNA and excision scar.

Hematopoietic stem cell transplantation for neuromyelitis optica spectrum disorder. Can immune tolerance be reestablished?

Neuromyelitis optica (NMO), which is also referred to as Devic's disease, was originally considered an aggressive subtype of multiple sclerosis (MS) presenting as optic neuritis and/or extensive transverse myelitis in which 50% of patients become blind or in a wheelchair within 5 years of onset. Subsequently, NMO was categorized as one of a spectrum of inflammatory and demyelinating autoimmune disorders that are distinct from multiple sclerosis and termed neuromyelitis optica spectrum disorder (NMOSD). NMOSD differs from multiple sclerosis by its clinical course, presentation, magnetic resonance imaging findings, clinical presentation, serum biomarker prognosis, and response to treatment. More recently, NMOSD has been subdivided according to auto-antibody status as aquaporin 4 (AQP4) seropositive NMO, myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD), and seronegative NMOSD. The only treatment to date that has resulted in treatment-free remissions, now lasting for more than 5-10 years with posttreatment disappearance of anti-AQP4 antibodies, is hematopoietic stem cell transplantation (HSCT) using either an allogeneic (matched sibling or unrelated) donor with a reduced toxicity conditioning regimen or an autologous stem cell source using a nonmyeloablative conditioning regimen of plasmapheresis (PLEX), cyclophosphamide (Cytoxan®), rabbit antithymocyte (ATG), and rituximab (Rituxan®). Post-HSCT long-term resolution of disease activity and disappearance of AQP4 antibodies is consistent with HSCT-induced immune tolerance.

Exploring Disparities in Pancreatic Ductal Adenocarcinoma Outcomes among Asian and Pacific Islander Subgroups.

Pancreatic ductal adenocarcinoma (PDAC) is a challenging malignancy with known disparities in outcomes across ethnicities. Studies specifically investigating PDAC in Asian populations are sparse, overlooking the rich diversity within this group. This research seeks to fill that gap by examining survival differences across the broad spectrum of Asian ethnicities, acknowledging the complexity and varied experiences within these communities. Utilizing the National Cancer Database from 2004 to 2019, we categorized patients into East Asian, Southeast Asian, South Asian, and Pacific Islander groups. Non-Asians or Pacific Islanders were excluded. Overall survival was analyzed using a Cox hazards model. The study consisted of 13,254 patients. Most patients were East Asian (59.4%, n = 7,866). Southeast Asians exhibited the poorest survival in unadjusted analysis (HR, 1.32; 95% confidence interval, 1.23-1.42; P < 0.001) compared with South Asians who exhibited the best survival. Multivariable analysis revealed significantly worse survival for East Asians and Pacific Islanders relative to South Asians, whereas Southeast Asians' results were not significantly different. Asian subgroup differences notably affect PDAC outcomes. Research on genetic and cultural aspects, especially in Southeast Asians, and tackling health disparities are crucial for enhancing survival in this diverse disease. SIGNIFICANCE: This study highlights the significant survival disparities among Asian subgroups with pancreatic cancer, utilizing a large national database. By differentiating among East Asian, Southeast Asian, South Asian, and Pacific Islander groups, it underscores the need for tailored research and healthcare approaches. Addressing these differences is essential for developing culturally sensitive interventions and potentially improving outcomes in a disease that uniquely affects these diverse populations.

Targeting IL-6 trans-signalling by sgp130Fc attenuates severity in SARS-CoV-2 -infected mice and reduces endotheliopathy.

BACKGROUND: SARS-CoV-2 infection is considered as a relapsing inflammatory process with a dysregulation of IL-6 signalling. Classic IL-6 signalling is thought to represent a defence mechanism against pathogens. In contrast, IL-6 trans-signalling has pro-inflammatory effects. In severe COVID-19, therapeutic strategies have focused on global inhibition of IL-6, with controversial results. We hypothesized that specific blockade of IL-6 trans-signalling could inhibit inflammatory response preserving the host defence activity inherent to IL-6 classic signalling. METHODS: To test the role of the specific IL-6 trans-signalling inhibition by sgp130Fc in short- and long-term consequences of COVID-19, we used the established K18-hACE2 transgenic mouse model. Histological as well as immunohistochemical analysis, and pro-inflammatory marker profiling were performed. To investigate IL-6 trans-signalling in human cells we used primary lung microvascular endothelial cells and fibroblasts in the presence/absence of sgp130Fc. FINDINGS: We report that targeting IL-6 trans-signalling by sgp130Fc attenuated SARS-CoV-2-related clinical symptoms and mortality. In surviving mice, the treatment caused a significant decrease in lung damage. In vitro, IL-6 trans-signalling induced strong and persisting JAK1/STAT3 activation in endothelial cells and lung fibroblasts with proinflammatory effects, which were attenuated by sgp130Fc. Our data also suggest that in those cells with scant amounts of IL-6R, the induction of gp130 and IL-6 by IL-6:sIL-6R complex sustains IL-6 trans-signalling. INTERPRETATION: IL-6 trans-signalling fosters progression of COVID-19, and suggests that specific blockade of this signalling mode could offer a promising alternative to mitigate both short- and long-term consequences without affecting the beneficial effects of IL-6 classic signalling. These results have implications for the development of new therapies of lung injury and endotheliopathy in COVID-19. FUNDING: The project was supported by ISCIII, Spain (COV-20/00792 to MB, PI23/01351 to MARH) and the European Commission-Next generation EU (European Union) (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI Salud Global, SGL2103029 to MB). PID2019-110587RB-I00 (MB) supported by MICIN/AEI/10.13039/501100011033/and PID2022-143034OB-I00 (MB) by MICIN/AEI/10.13039/501100011033/FEDER. MAR-H acknowledges support from ISCIII, Spain and the European Commission-Next generation EU (European Union), through CSIC's Global Health PTI.

Is it resectable? A survey regarding tumor classification and vascular involvement.

INTRODUCTION: The anatomic location of the pancreas can result in involvement of major vasculature, which may act as a contraindication to resection. Several classification systems have been developed. We sought to discover the variations in the HPB community determining PDAC resectability. METHODS: The multiple-choice survey was distributed to all full members of the IHPBA. Questions were asked regarding demographics and clinical scenarios regarding tumor resectability. RESULTS: 164 responses were submitted. Most of the respondents were male and had been in practice for over 10 years. The median age range was 40-50 years old. Most practiced in either Asia (n = 57,35.9%), North America (n = 52,32.7%), or Europe (n = 32,20.1%). Classification systems used to determine resectability were: NCCN (n = 42,26.3%), JPS (n = 35,21.9%), International consensus (n = 33,20.6%), AHPBA/SSO (n = 23,14.4%), Alliance (n = 3,1.9%), and other/no-classification (n = 23,14.5%). There was significant variation in the frequency of the most common answer within the scenarios (84.7%-33.5%). Participant concordance with their stated classification system found a median rate of 62.5%. Participant decision of tumor resectability was not dependent on their adopted classification system. CONCLUSION: When classifying PDAC resectability, there is significant variation between surgeons as to how they would classify a specific tumour, independent of the classification system they use. In addition, surgeons do not show high concordance with the definitions within that classification system.

Functional donor-site morbidity following reconstruction with pectoralis major flaps: A systematic review.

Background: Pectoralis major muscle/myocutaneous flaps (PMMFs) are commonly used in reconstructive surgery, but may result in shoulder disability on the donor side. A systematic review evaluating this morbidity could be beneficial for guiding patients and providers considering this procedure. Methods: In October 2022, a systematic review of studies evaluating quantitative/qualitative measures of functional morbidity after PMMF was conducted. The results were categorized into PMMF's effect on range of motion (ROM), strength, and ability to complete shoulder-related activities/quality of life. Results: Eleven studies were included for analysis, which analyzed standard PMMF and two PMMF variants that spared portions of the muscle. Three of five studies demonstrated reduced shoulder ROM for standard PMMF versus controls lasting at least 4 months after head and neck reconstruction. Two of five studies, including two prospective studies demonstrated reduced shoulder strength for standard PMMF versus controls lasting at least 3 months after surgery. Five of nine studies found significant impairment in the ability to conduct shoulder-related activities, including work, up to one year postoperatively for standard PMMF versus controls. Muscle-sparing PMMF variants exhibited more promising outcomes in some categories. Conclusion: Standard PMMF results in prolonged reductions in shoulder ROM and strength, which may impair patients in shoulder-related activities. Other reconstructive options should be considered in patients who frequently participate in such activities. For patients requiring PMMF, muscle-sparing PMMF variants should be considered as alternatives to the standard PMMF.

Computationally designed sensors detect endogenous Ras activity and signaling effectors at subcellular resolution.

The utility of genetically encoded biosensors for sensing the activity of signaling proteins has been hampered by a lack of strategies for matching sensor sensitivity to the physiological concentration range of the target. Here we used computational protein design to generate intracellular sensors of Ras activity (LOCKR-based Sensor for Ras activity (Ras-LOCKR-S)) and proximity labelers of the Ras signaling environment (LOCKR-based, Ras activity-dependent Proximity Labeler (Ras-LOCKR-PL)). These tools allow the detection of endogenous Ras activity and labeling of the surrounding environment at subcellular resolution. Using these sensors in human cancer cell lines, we identified Ras-interacting proteins in oncogenic EML4-Alk granules and found that Src-Associated in Mitosis 68-kDa (SAM68) protein specifically enhances Ras activity in the granules. The ability to subcellularly localize endogenous Ras activity should deepen our understanding of Ras function in health and disease and may suggest potential therapeutic strategies.

What would you do? A survey of HPB surgeons practice patterns.

BACKGROUND: The surgical decision making for pancreatic adenocarcinoma is complex. Although practice guidelines exist for many scenarios, these do not cover many common eventualities that may be encountered during these cases. We sought to identify the practice pattern variations amongst pancreatic surgeons in response to commonly experienced clinical scenarios. METHODS: A multiple-choice questionnaire was distributed to all full members of the IHPBA. Participant demographics, training history, and clinical practice information were obtained. The survey provided various operative scenarios and participants were asked how they would likely proceed. Responses were collected and stored anonymously in a secure database. Statistical analysis was performed using Stata 16.0. RESULTS: 164 responses were submitted. Most of the respondents were male and had been in practice for over 10 years. The median age range was 40-50 years old. When asked about staging laparoscopy, the majority performed it selectively. For most respondents a pathological aorto-caval nodes was a reason to abort the procedure but most would have continued in the setting of a positive hepatic artery node. When encountering a single Segment 2 liver metastasis, participants who practiced in Europe were significantly more likely to resect and proceed compared to those in Asia and North America. Participants who had undergone only a Surgical Oncology fellowship were most likely to abort. With respect to direct colonic invasion, most participants would resect the specimen en bloc. Respondents who participated in fewer that 20 PDAC operations/year were most likely to abort. CONCLUSIONS: Surgical decision making in PDAC surgery is complex and there is significant disagreement on the correct management. While formal guidelines cannot exist for all situations, this survey highlights the need for consensus on commonly encountered operative scenarios.