3D-printing hydrogel programmed released exosomes to restore aortic medial degeneration through inhibiting VSMC ferroptosis in aortic dissection.

Aortic dissection (AD) is a devastating disease with a high mortality rate. Exosomes derived from mesenchymal stem cells (exo-MSCs) offer a promising strategy to restore aortic medial degeneration and combat ferroptosis in AD. However, their rapid degradation in the circulatory system and low treatment efficiency limit their clinical application. Methylacrylated gelatin (Gelma) was reported as a matrix material to achieve controlled release of exosomes. Herein, exo-MSCs-embedded in Gelma hydrogels (Gelma-exos) using ultraviolet light and three-dimensional (3D) printing technology. These Gelma-exos provide a sustained release of exo-MSCs as Gelma gradually degrades, helping to restore aortic medial degeneration and prevent ferroptosis. The sustained release of exosomes can inhibit the phenotypic switch of vascular smooth muscle cells (VSMCs) to a proliferative state, and curb their proliferation and migration. Additionally, the 3D-printed Gelma-exos demonstrated the ability to inhibit ferroptosis in vitro, in vivo and ex vivo experiments. In conclusion, our Gelma-exos, combined with 3D-printed technology, offer an alternative treatment approach for repairing aortic medial degeneration and ferroptosis in AD, potentially reducing the incidence of aortic dissection rupture.

Roux-en-Y gastric bypass versus duodenal switch in patients with body mass index ≥50 kg/m2: a systematic review and meta-analysis.

Currently, there is no consensus on the best bariatric surgery type for patients with body mass index (BMI) ≥50 kg/m2. This systematic review and meta-analysis aimed to compare outcomes of duodenal switch (DS) and Roux-en-Y gastric bypass (RYGB) in terms of weight loss, resolution of obesity-related comorbidities, and complications among patients with a BMI ≥50 kg/m2. A systematic search was conducted across databases including PubMed, Embase, Scopus, and Web of Science to include studies that compared outcomes of DS and RYGB in patients with BMI ≥50 kg/m2. A meta-analysis was carried out, alongside subgroup analyses based on the type of study and duration of follow-up. Twelve articles were included in this study (2678 patients, follow-up: 1-15 years). Patients with DS had 7.31 kg/m2 higher BMI loss (95% CI: 5.59-9.03, P < .001) and 9.9% more total weight loss (95% CI: 4.47-15.28%, P < .001) compared with RYGB. The rate of complications, reoperation, mortality, and remission of comorbidities including diabetes, hypertension, dyslipidemia, and obstructive sleep apnea was not significantly different between DS and RYGB. Rate of malnutrition was 8.3% in the DS group compared with 1.2% in RYGB (OR: 5.53, 95% CI: 1.35-22.44, P = .02). In addition, 5.4% DS patients needed revisional surgery for malnutrition versus none in RYGB (OR: 6.1, 95% CI: 1.03-36.33, P = .05), and 24.6% of DS patients developed gallbladder disease needed cholecystectomy versus 4.5% after RYGB (OR: 6.36, 95% CI: 1.70-23.82, P = .01). DS leads to significantly higher BMI and total weight loss in patients with BMI ≥50 kg/m2 but may be associated with a higher rate of major malnutrition and needed revisional surgery. These should be considered in surgical planning.

Long non-coding RNA GRASLND links melanoma differentiation and interferon-gamma response.

Melanoma is a highly malignant tumor, that stands as the most lethal form of skin cancer and is characterized by notable phenotypic plasticity and intratumoral heterogeneity. Melanoma plasticity is involved in tumor growth, metastasis and therapy resistance. Long non-coding RNAs (lncRNAs) could influence plasticity due to their regulatory function. However, their role and mode of action are poorly studied. Here, we show a relevance of lncRNA GRASLND in melanoma differentiation and IFNγ signaling. GRASLND knockdown revealed switching of differentiated, melanocytic melanoma cells towards a dedifferentiated, slow-proliferating and highly-invasive cell state. Interestingly, GRASLND is overexpressed in differentiated melanomas and associated with poor prognosis. Accordingly, we found GRASLND expressed in immunological "cold" tumors and it negatively correlates with gene signatures of immune response activation. In line, silencing of GRASLND under IFNγ enhanced the expression of IFNγ-stimulated genes, including HLA-I antigen presentation, demonstrating suppressive activity of GRASLND on IFNγ signaling. Our findings demonstrate that in differentiated melanomas elevated expression of GRASLND interferes with anti-tumor effects of IFNγ, suggesting a role of GRASLND in tumor immune evasion.

Delayed Presentation of Baffle Obstruction in an Adult Post-Mustard Repair of Transposition: Computed Tomography Demonstration.

Atrial switch surgery is performed in patients with transposition of the great arteries. One of the complications of this surgery is obstruction of the baffle created. We describe the computed tomography findings of one such case where there was delayed presentation of recurrent Mustard baffle obstruction in addition to pulmonary venous drainage obstruction in an adult previously operated on for intra-atrial repair of transposition of the great arteries.

Impact of Disease Factors of Patients with Psoriasis and Psoriatic Arthritis on Biologic Therapy Switching: Real-World Evidence from the CorEvitas Psoriasis Registry.

INTRODUCTION: Patients with psoriasis (PSO) and psoriatic arthritis (PsA) may frequently switch biologic therapies over the course of treatment because of symptom variability and individual responses. Real-world studies analyzing patient characteristics and clinical factors associated with biologic switching are limited. METHODS: This longitudinal cohort study used real-world data from the CorEvitas Psoriasis Registry to evaluate the relationship between associated disease factors and biologic switching among patients with PSO and PsA in the United States (US) and Canada following initiation of a biologic. Patients were evaluated between April 2015-August 2022. Combinations of disease severity (as measured by Psoriasis Area Severity Index [PASI]) and Dermatology Life Quality Index (DLQI) as a measure of health-related quality of life (HRQoL) were assessed, and the association with time to switching was calculated using Cox proportional hazards regression modeling. RESULTS: Among 2580 patient-initiations (instances of patients initiating a biologic), 504 (19.5%) switched biologics within 30 months of initiation. Switching was more frequent when either PASI > 10 or DLQI > 5 compared with PASI ≤ 10 or DLQI ≤ 5 at follow-up. Patients with higher skin involvement (PASI > 10) and impact on HRQoL (DLQI > 5) were 14 times more likely to switch (hazard ratio = 14.2, 95% confidence interval: 10.7, 18.9) than those with lower skin involvement (PASI ≤ 10) and HRQoL (DLQI ≤ 5). CONCLUSIONS: Patients with PSO and PsA treated in a real-world dermatology setting with substantial disease factors following biologic initiation were more likely to switch therapies. Those with PASI > 10 and DLQI > 5 switched more frequently than those with PASI ≤ 10 and DLQI ≤ 5.

Many patients with psoriasis may also have a related condition called psoriatic arthritis. Biologic medications work by helping to reduce inflammation and are commonly used to treat the symptoms of psoriasis and psoriatic arthritis. Patients might not all respond the same way to treatment and may need to change their medications over time. It is important we understand the reasons for switching medications to help patients better manage their symptoms.This study used information from a database on patients with both psoriasis and psoriatic arthritis. The database includes information on patients' medical history, including when they start and change their medication. We looked at data from patients who switched medications and patients who did not switch medications and examined differences in both how serious a doctor found their disease and the patients' own opinions of their overall health.We found that patients were more likely to change their biologic medication if they had more difficult psoriasis and psoriatic arthritis symptoms that caused worse skin problems, joint pain, and effects on their overall health compared with patients who had not changed their medication. These results suggest that it is important to consider both how serious a doctor finds their disease and patients' opinions of how much their symptoms affect their overall health. Understanding the reasons why patients switch medications will help to develop better ways of managing psoriasis and psoriatic arthritis.

Single Anastomosis Duodeno-Ileostomy with Sleeve Gastrectomy/Single Anastomosis Duodenal Switch (SADI-S/SADS) IFSO Position Statement-Update 2023.

The single anastomosis duodeno-ileostomy with sleeve gastrectomy/single anastomosis duodenal switch (SADI-S/SADS) has gained attention as an alternative to the traditional biliopancreatic diversion with duodenal switch (BPD-DS). In 2021, IFSO endorsed SADI-S/SADS as a safe and effective procedure, underscoring the necessity for long-term multidisciplinary care and randomized controlled trials (RCTs). A task force was established to conduct a systematic review of current evidence on SADI-S/SADS to guide clinical practice. A systematic review was conducted across three databases, focusing on studies examining SADI-S/SADS and its outcomes. A total of 93 studies were analyzed. SADI-S/SADS demonstrated efficacy in weight loss and medium-to-long-term control of type 2 diabetes mellitus (T2DM), along with positive outcomes regarding hypertension and hyperlipidemia. However, its impact on other comorbidities remains inconclusive. Frequent nutritional deficiencies were identified, particularly in fat-soluble vitamins, anemia, and hypoalbuminemia. Despite significant efforts, high-quality evidence on SADI-S/SADS remains scarce, prompting IFSO to advocate for increased registry participation, publication of long-term studies, and more RCTs. Lifelong supplementation and monitoring for nutritional deficiencies are recommended. The current position statement will be reviewed in 2 years.

A molten globule ensemble primes Arf1-GDP for the nucleotide switch.

The adenosine di-phosphate (ADP) ribosylation factor (Arf) small guanosine tri-phosphate (GTP)ases function as molecular switches to activate signaling cascades that control membrane organization in eukaryotic cells. In Arf1, the GDP/GTP switch does not occur spontaneously but requires guanine nucleotide exchange factors (GEFs) and membranes. Exchange involves massive conformational changes, including disruption of the core ß-sheet. The mechanisms by which this energetically costly switch occurs remain to be elucidated. To probe the switch mechanism, we coupled pressure perturbation with nuclear magnetic resonance (NMR), Fourier Transform infra-red spectroscopy (FTIR), small-angle X-ray scattering (SAXS), fluorescence, and computation. Pressure induced the formation of a classical molten globule (MG) ensemble. Pressure also favored the GDP to GTP transition, providing strong support for the notion that the MG ensemble plays a functional role in the nucleotide switch. We propose that the MG ensemble allows for switching without the requirement for complete unfolding and may be recognized by GEFs. An MG-based switching mechanism could constitute a pervasive feature in Arfs and Arf-like GTPases, and more generally, the evolutionarily related (Ras-like small GTPases) Rags and Gα GTPases.

Network medicine based approach for identifying the type 2 diabetes, osteoarthritis and triple negative breast cancer interactome: Finding the hub of hub genes.

The increasing prevalence of multi-morbidities, particularly the incidence of breast cancer in diabetic/osteoarthritic patients emphasize on the need for exploring the underlying molecular mechanisms resulting in carcinogenesis. To address this, present study employed a systems biology approach to identify switch genes pivotal to the crosstalk between diseased states resulting in multi-morbid conditions. Hub genes previously reported for type 2 diabetes mellitus (T2DM), osteoarthritis (OA), and triple negative breast cancer (TNBC), were extracted from published literature and fed into an integrated bioinformatics analyses pipeline. Thirty-one hub genes common to all three diseases were identified. Functional enrichment analyses showed these were mainly enriched for immune and metabolism associated terms including advanced glycation end products (AGE) pathways, cancer pathways, particularly breast neoplasm, immune system signalling and adipose tissue. The T2DM-OA-TNBC interactome was subjected to protein-protein interaction network analyses to identify meta hub/clustered genes. These were prioritized and wired into a three disease signalling map presenting the enriched molecular crosstalk on T2DM-OA-TNBC axes to gain insight into the molecular mechanisms underlying disease-disease interactions. Deciphering the molecular bases for the intertwined metabolic and immune states may potentiate the discovery of biomarkers critical for identifying and targeting the immuno-metabolic origin of disease.

Rationale and Design of the COPERNIC Trial: A Study of On-treatment ctDNA Changes in Chemo-refractory Colorectal Cancer Patients.

BACKGROUND: Evidence suggests that ctDNA may be a reliable biomarker to monitor metastatic colorectal cancer (CRC) evolution. Nevertheless, evidence on the potential of liquid biopsy in this setting is still low quality, mostly consisting of retrospective studies. METHODS: COPERNIC is an international, multicenter clinical trial. The pilot study aims to confirm the predictive potential of early on-treatment ctDNA dynamics, and inform the design of a larger ctDNA-driven trial. Advanced CRC patients who are candidates for ≥3rd lines of systemic therapy undergo longitudinal blood sample collection during treatment (day 1, 15 and 29 for 2- or 4-weekly treatment regimens; day 1, 22 and 43 for 3-weekly treatment regimens) and at each imaging assessment. ctDNA analyses are carried out with the FoundationOne Liquid CDx and FoundationOneMonitor assays, and ctDNA changes during treatment are correlated with radiologic response (as assessed every 8-12 weeks by RECIST v1.1). The primary objective is to select the optimal timepoint and cut-off value for early ctDNA changes (at day 15/22) to predict progressive disease as best radiological response with a high positive predictive value. The cut-off value for ctDNA will be defined based on nonparametric ROC-curves with bootstrapping. Based on the expected rate of progressive disease and statistical assumptions, 109 patients are needed to be screened to have 87 assessable patients. COPERNIC is sponsored by the Institut Jules Bordet, and supported by Roche and Foundation Medicine. Recruitment is open in 13 centres across Belgium and France. The study is registered with clinicaltrials.gov (NCT05487248).

Switch to faricimab after initial treatment with aflibercept in eyes with neovascular age-related macular degeneration.

PURPOSE: To investigate the efficacy and outcomes of switching neovascular age-related macular degeneration (nAMD) patients from aflibercept to faricimab, focusing on visual acuity, retinal fluid management, and treatment intervals. The primary aim was to assess the early outcomes in nAMD patients refractory to aflibercept and explore faricimab's potential as a longer-lasting therapeutic alternative. METHODS: A single-center retrospective study was conducted on 50 refractory nAMD patients at Cleveland Clinic Abu Dhabi from September 2022-May 2023. Patients were switched from aflibercept to faricimab, having met specific criteria for refractory nAMD. The study analyzed best-corrected visual acuity (BCVA), central subfield thickness (CST), and fluid changes post-switch, using Optical Coherence Tomography (OCT). RESULTS: After three faricimab injections, significant reductions in CST were observed, with a notable decrease in retinal fluid. The mean BCVA remained stable throughout the study period. Although there was a decrease in the maximum pigment epithelial detachment (PED) height, it was not statistically significant. Treatment intervals post-switch showed that the majority of patients maintained or extended their treatment intervals, with a significant proportion achieving resolution of intraretinal fluid (IRF) and subretinal fluid (SRF). CONCLUSIONS: Switching to faricimab from aflibercept in refractory nAMD patients led to significant improvements in retinal fluid management and CST, with stable BCVA outcomes. Faricimab presents a promising alternative for patients requiring frequent aflibercept injections, potentially offering a more manageable treatment regimen with extended dosing intervals. This study highlights the need for personalized therapeutic strategies in nAMD treatment, though further research is necessary to optimize treatment switches.

Bariatric Surgery: Current Trends and Newer Surgeries.

Bariatric surgery has evolved and gained in popularity as it has been recognized as the most sustainable and effective treatment for obesity and related diseases. These related diseases are significant causes of obesity related morbidity and mortality. Most bariatric procedures incorporate some component of gastric restriction with or without intestinal bypass, but the full mechanism of these procedures has yet to be elucidated. The most popular surgical procedure remains the sleeve gastrectomy over the last 10 years, while gastric bypass is also still commonly performed. We have also seen growth in revisional bariatric surgery and novel surgical procedures.

Blocking the PD-1 signal transduction by occupying the phosphorylated ITSM recognition site of SHP-2.

Targeting the PD-1/PD-L1 axis with small-molecular inhibitors is a promising approach for immunotherapy. Here, we identify a natural pentacyclic triterpenoid, Pygenic Acid A (PA), as a PD-1 signaling inhibitor. PA exerts anti-tumor activity in hPD-1 knock-in C57BL/6 mice and enhances effector functions of T cells to promote immune responses by disrupting the PD-1 signaling transduction. Furthermore, we identify SHP-2 as the direct molecular target of PA for inhibiting the PD-1 signaling transduction. Subsequently, mechanistic studies suggest that PA binds to a new druggable site in the phosphorylated PD-1 ITSM recognition site of SHP-2, inhibiting the recruitment of SHP-2 by PD-1. Taken together, our findings demonstrate that PA has a potential application in cancer immunotherapy and occupying the phosphorylated ITSM recognition site of SHP-2 may serve as an alternative strategy to develop PD-1 signaling inhibitors. In addition, our success in target recognition provides a paradigm of target identification and confirmation for natural products.

Methadone Conversion Using a 3-Day Switch Strategy in Patients with Cancer on High-Dose Opioids: A Retrospective Study.

INTRODUCTION: Methadone has shown effectiveness in pain control in patients with cancer who are intolerant to other opioids in China. However, the optimal strategy for methadone conversion from previous high doses of opioids in refractory cancer pain remains debatable. This study aimed to describe the efficacy and safety of a 3-day switch (3DS) strategy for methadone conversion in patients with refractory cancer pain on high doses of opioids. METHODS: We retrospectively reviewed 30-day medical records of 70 patients with refractory cancer pain who used a 3DS strategy for methadone conversion from previous high doses of opioids from July 2018 to December 2022. The 3DS strategy indicated that the methadone dose was increased by one third every day for 3 days. Data on the rate of successful conversion, the time to stable analgesia after conversion, the conversion efficiency, the corrected QT (QTc) interval, the actual conversion ratios, adverse events (AEs), and quality of life were analyzed. RESULTS: Seventy patients received 3DS methadone conversion and 64 patients were eligible for analysis. Fifty patients (78%) achieved stable analgesia, and the median time to stable analgesia was 8.14 ± 2.70 (range 6-14) days. The average dose of methadone was 77.94 ± 42.74 mg. The most common AEs (≥ 10%) included constipation, dry mouth, nausea, and cold sweats. The incidence of constipation was reduced post-methadone conversion, and a statistically significant but asymptomatic prolongation of the QTc interval was observed. Additionally, the actual conversion ratios were lower than Ayonrinde's recommended ratios. CONCLUSIONS: The 3DS strategy for methadone conversion is applicable in Chinese patients with refractory cancer pain on high doses of opioids.

Prediction of PSA Response after Dexamethasone Switch during Abiraterone Acetate + Prednisolone Treatment of Metastatic Castration-Resistant Prostate Cancer Patients.

BACKGROUND: The aim was to elaborate a predictive model to find responders for the corticosteroid switch (from prednisolone to dexamethasone) at the first prostate-specific antigen (PSA) progression (≥25% increase) during abiraterone acetate (AA) treatment of metastatic castration-resistant prostate cancer (mCRPC) patients. METHODS: If PSA has decreased (≥25%) after switch, patients were considered responders. Logistic regression of 19 dichotomized parameters from routine laboratory and patients' history was used to find the best model in a cohort of 67 patients. The model was validated in another cohort of 42 patients. RESULTS: The model provided 92.5% and 90.5% accuracy in the testing and the validation cohorts, respectively. Overall the accuracy was 91.7%. The AUC of ROC curve was 0.92 (95% CI 0.85-0.96). After a median follow-up of 27.9 (26.3-84) months, the median AA+dexamethasone treatment duration (TD) in non-responders and responders was 4.7 (3.1-6.5) and 11.1 (8.5-12.9) months and the median overall survival (OS) was 23.2 (15.6-25.8) and 33.5 (26.1-38) months, respectively. Multivariate Cox regression revealed that responsiveness was an independent marker of TD and OS. CONCLUSIONS: A high accuracy model was developed for mCRPC patients in predicting cases which might benefit from the switch. For non-responders, induction of the next systemic treatment is indicated.

Shedding more than weight: Metabolic and bariatric surgery and the journey to insulin independence in insulin-treated type 2 diabetes.

BACKGROUND: Type 2 diabetes (T2D) imposes a significant health burden, necessitating lifelong pharmacological interventions, with insulin being one of the cornerstone therapies. However, these regimens are associated with health risks and psychological stressors. This study aimed to examine the rates of insulin-treated T2D remission and cessation or reduction in the dosage of insulin therapy after metabolic and bariatric surgery (MBS). METHODS: This was a retrospective analysis of patients with a preoperative diagnosis of insulin-treated T2D who underwent primary laparoscopic sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), or biliopancreatic diversion with duodenal switch (BPD/DS) with a minimum of 3 and up to 5 years of follow-up. The average daily dose for each type of insulin, measured in units, was calculated at annual intervals. RESULTS: Among 287 patients included, 201 (70%) underwent RYGB, 66 (23%) underwent SG, and 20 (7%) underwent BPD/DS. The average follow-up period was 4.6 ± 0.7 years. At 5 years follow-up, the mean total weight loss was the highest in the BPD/DS subgroup at 37.5% ± 11.6%. Insulin usage decreased significantly from complete dependency at baseline to 36.2% just 1 year postoperatively, and the use of noninsulin antidiabetic drugs decreased from 79.4% initially to 26.1%. These results were sustained throughout the study period. The subgroup analysis indicated that, 5 years after surgery, T2D remission was the highest after BPD/DS (73.7%) compared with RYGB (43.2%) and SG (23.3%) (P < .001). CONCLUSION: MBS is a transformative approach for achieving significant remission in insulin-treated T2D and reducing insulin requirements. Our findings reinforce the efficacy of these surgical interventions, particularly highlighting the promising potential of procedures that bypass the proximal small intestine, such as BPD/DS and RYGB.

Genetic switch selectively kills hepatocellular carcinoma cell based on microRNA and tissue-specific promoter.

The clinical treatment of hepatocellular carcinoma (HCC) is still a heavy burden worldwide. Intracellular microRNAs (miRNAs) commonly express abnormally in cancers, thus they are potential therapeutic targets for cancer treatment. miR-21 is upregulated in HCC whereas miR-122 is enriched in normal hepatocyte but downregulated in HCC. In our study, we first generated a reporter genetic switch compromising of miR-21 and miR-122 sponges as sensor, green fluorescent protein (GFP) as reporter gene and L7Ae:K-turn as regulatory element. The reporter expression was turned up in miR-21 enriched environment while turned down in miR-122 enriched environment, indicating that the reporter switch is able to respond distinctly to different miRNA environment. Furthermore, an AAT promoter, which is hepatocyte-specific, is applied to increase the specificity to hepatocyte. A killing switch with AAT promoter and an apoptosis-inducing element, Bax, in addition to miR-21 and miR-122 significantly inhibited cell viability in Huh-7 by 70 % and in HepG2 by 60 %. By contrast, cell viability was not affected in five non-HCC cells. Thus, we provide a novel feasible strategy to improve the safety of miRNA-based therapeutic agent to cancer.

Rare events model of the MBSAQIP database: risk of early bowel obstruction following metabolic surgery.

BACKGROUND: Early small bowel obstruction (eSBO) (within 30-days) is a rare but important complication that is associated with high rates of morbidity, including readmission, reintervention, and reoperation. OBJECTIVES: To identify patient-specific and operation-specific characteristics that predispose patients to eSBO and to identify at-risk individuals preoperatively. SETTING: 2015-2021 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP). METHODS: Utilizing the 2015-2021 MBSAQIP PUF, 1,016,484 records were analyzed. Pediatric, revisional, open-conversion, and cases with incomplete data in sex, body mass index, operative-time, 30-day-follow-up variables were excluded. Case details were compared using Fisher's exact & Wilcoxon -Mann -Whitney tests to identify at-risk patients. The likelihood of eSBO was modeled with rare event logistic regression. RESULTS: Incidence of eSBO was .40%. Of the 4103 occurrences of eSBO, RYGB (Roux-en-Y gastric bypass), SG (sleeve gastrectomy), and DS (duodenal switch) accounted for 79.4%, 19.3%, and 1.3%, respectively. Many patient-specific characteristics were significantly associated with eSBO. History of prior foregut surgery, a non-metabolic surgery trained operator, and longer operative times were all associated with increased eSBO (P < .0001). While simultaneously controlling for these factors, eSBO remained higher in DS (OR 9.55, P < .0001) and RYGB (OR 5.18, P < .0001) compared to SG. Increased length of operation (OR 1.03, P < .0001) and non -MS-trained operators (OR 1.33, P < .0001) remained highly significant. Male-sex (OR .70, P < .0001) and diabetes (OR .78, P < .0001) were both protective. CONCLUSIONS: In the largest analysis to date, eSBO remains a rare event. RYGB accounts for the largest proportion of eSBO, however, DS has a higher risk adjusted rate of eSBO.

RAD18- and BRCA1-dependent pathways promote cellular tolerance to the nucleoside analog ganciclovir.

Ganciclovir (GCV) is a clinically important drug as it is used to treat viral infections. GCV is incorporated into the DNA during replication, where it interferes with subsequent replication on GCV-incorporated templates. However, the effects of GCV on the host genome and the mechanisms underlying cellular tolerance to GCV remain unclear. In this study, we explored these mechanisms using a collection of mutant DT40 cells. We identified RAD17/-, BRCA1-/-, and RAD18-/- cells as highly GCV-sensitive. RAD17, a component of the alternative checkpoint-clamp loader RAD17-RFC, was required for the activation of the intra-S checkpoint following GCV treatment. BRCA1, a critical factor for promoting homologous recombination (HR), was required for suppressing DNA double-strand breaks (DSBs). Moreover, RAD18, an E3-ligase involved in DNA repair, was critical in suppressing the aberrant ligation of broken chromosomes caused by GCV. We found that BRCA1 suppresses DSBs through HR-mediated repair and template switching (TS)-mediated damage bypass. Moreover, the strong GCV sensitivity of BRCA1-/- cells was rescued by the loss of 53BP1, despite the only partial restoration in the sister chromatid exchange events which are hallmarks of HR. These results indicate that BRCA1 promotes cellular tolerance to GCV through two mechanisms, TS and HR-mediated repair.

Therapeutic applications of synthetic gene/genetic circuits: a patent review.

A significant limitation of numerous current genetic engineering therapy approaches is their limited control over the strength, timing, or cellular context of their therapeutic effect. Synthetic gene/genetic circuits are synthetic biology approaches that can control the generation, transformation, or depletion of a specific DNA, RNA, or protein and provide precise control over gene expression and cellular behavior. They can be designed to perform logical operations by carefully selecting promoters, repressors, and other genetic components. Patent search was performed in Espacenet, resulting in 38 selected patents with 15 most frequent international classifications. Patent embodiments were categorized into applications for the delivery of therapeutic molecules, treatment of infectious diseases, treatment of cancer, treatment of bleeding, and treatment of metabolic disorders. The logic gates of selected genetic circuits are described to comprehensively demonstrate their therapeutic applications. Synthetic gene circuits can be customized for precise control of therapeutic interventions, leading to personalized therapies that respond specifically to individual patient needs, enhancing treatment efficacy and minimizing side effects. They can be highly sensitive biosensors that provide real-time therapy by accurate monitoring various biomarkers or pathogens and appropriately synthesizing a therapeutic molecule. Synthetic gene circuits may also lead to the development of advanced regenerative therapies and to implantable biodevices that produce on-demand bioactive molecules. However, this technology faces challenges for commercial profitability. The genetic circuit designs need adjustments for specific applications, and may have disadvantages like toxicity from multiple regulators, homologous recombination, context dependency, resource overuse, and environmental variability.

Un-methylation of NUDT21 represses docosahexaenoic acid biosynthesis contributing to enzalutamide resistance in prostate cancer.

AIMS: The recent approval of enzalutamide for metastatic castration-sensitive prostate cancer underscores its growing clinical significance, raising concerns about emerging resistance and limited treatment options. While the reactivation of the androgen receptor (AR) and other genes plays a role in enzalutamide resistance, identifications of novel underlying mechanism with therapeutic potential in enzalutamide-resistant (EnzaR) cells remain largely elusive. METHODS: Drug-resistant prostate cancer cell lines, animal models, and organoids were utilized to examine NUDT21 function by transcriptomic and metabolomic analyses through loss-of-function and gain-of-function assays. Notably, a mono-methylation monoclonal antibody and conditional-knockin transgenic mouse model of NUDT21 were generated for evaluating its function. RESULTS: NUDT21 overexpression acts as a crucial alternative polyadenylation (APA) mediator, supported by its oncogenic role in prostate cancer. PRMT7-mediated mono-methylation of NUDT21 induces a shift in 3'UTR usage, reducing oncogenicity. In contrast, its un-methylation promotes cancer growth and cuproptosis insensitivity in EnzaR cells by exporting toxic copper and suppressing docosahexaenoic acid (DHA) biosynthesis. Crucially, NUDT21 inhibition or DHA supplementation with copper ionophore holds therapeutic promise for EnzaR cells. CONCLUSIONS: The un-methylation of NUDT21-mediated 3'UTR shortening unveils a novel mechanism for enzalutamide resistance, and our findings offer innovative strategies for advancing the treatment of prostate cancer patients experiencing enzalutamide resistance.