Citations

Abstract Although initial therapy of mantle cell lymphoma (MCL) is not standardized, bendamustine plus rituximab (BR) is commonly used in older patients. Rituximab (R) maintenance after induction is often used. Thus, the open-label, randomized phase 2 ECOG-ACRIN Cancer Research Group E1411 trial was designed to test 2 questions: (1) does addition of bortezomib to BR induction (BVR) and/or (2) addition of lenalidomide to rituximab (LR) maintenance improve progression-free survival (PFS) in patients with treatment-naïve MCL? From 2012 to 2016, 373 previously untreated patients, 87% aged ≥60 years, were enrolled in this trial. At a median follow-up of 7.5 years, there is no difference in the median PFS of BR compared with BVR (5.5 vs 6.4 years; hazard ratio [HR], 0.90; 90% confidence interval [CI], 0.70-1.16). There were no unexpected additional toxicities with BVR treatment compared with BR, with no impact on total dose/duration of treatment received. Independent of the induction treatment, addition of lenalidomide did not significantly improve PFS, with median PFS in R vs LR (5.9 vs 7.2 years; HR, 0.84; 90% CI, 0.62-1.15). Most patients completed the planned 24 cycles of LR at the scheduled dose. In summary, adding bortezomib to BR induction does not prolong PFS in treatment-naïve MCL, and LR maintenance was not associated with longer PFS compared with R alone after BR. Nonetheless, the >5-year median PFS outcomes in this prospective cooperative group trial indicate the efficacy of BR followed by R maintenance as highly effective initial therapy for older patients with MCL. This trial was registered at www.clinicaltrials.gov as #NCT01415752.

AbstractDNA damage plays a significant role in the tumorigenesis and progression of the disease. Abnormal DNA repair affects the therapy and prognosis of cancer. In this study, it is demonstrated that the deubiquitinase USP25 promotes non‐homologous end joining (NHEJ), which in turn contributes to chemoresistance in cancer. It is shown that USP25 deubiquitinates SHLD2 at the K64 site, which enhances its binding with REV7 and promotes NHEJ. Furthermore, USP25 deficiency impairs NHEJ‐mediated DNA repair and reduces class switch recombination (CSR) in USP25‐deficient mice. USP25 is overexpressed in a subset of colon cancers. Depletion of USP25 sensitizes colon cancer cells to IR, 5‐Fu, and cisplatin. TRIM25 is also identified, an E3 ligase, as the enzyme responsible for degrading USP25. Downregulation of TRIM25 leads to an increase in USP25 levels, which in turn induces chemoresistance in colon cancer cells. Finally, a peptide that disrupts the USP25‐SHLD2 interaction is successfully identified, impairing NHEJ and increasing sensitivity to chemotherapy in PDX model. Overall, these findings reveal USP25 as a critical effector of SHLD2 in regulating the NHEJ repair pathway and suggest its potential as a therapeutic target for cancer therapy.

DNA replication is a vulnerable cellular process, and its deregulation leads to genomic instability. Here, we demonstrate that chromobox protein homolog 3 (CBX3) binds replication protein A 32-kDa subunit (RPA2) and regulates RPA2 retention at stalled replication forks. CBX3 is recruited to stalled replication forks by RPA2 and inhibits ring finger and WD repeat domain 3 (RFWD3)–facilitated replication restart. Phosphorylation of CBX3 at serine-95 by casein kinase 2 (CK2) kinase augments cadherin 1 (CDH1)–mediated CBX3 degradation and RPA2 dynamics at stalled replication forks, which permits replication fork restart. Increased expression of CBX3 due to gene amplification or CK2 inhibitor treatment sensitizes prostate cancer cells to poly(ADP-ribose) polymerase (PARP) inhibitors while inducing replication stress and DNA damage. Our work reveals CBX3 as a key regulator of RPA2 function and DNA replication, suggesting that CBX3 could serve as an indicator for targeted therapy of cancer using PARP inhibitors.

Abstract Objectives Precise literature recommendation and summarization are crucial for biomedical professionals. While the latest iteration of generative pretrained transformer (GPT) incorporates 2 distinct modes—real-time search and pretrained model utilization—it encounters challenges in dealing with these tasks. Specifically, the real-time search can pinpoint some relevant articles but occasionally provides fabricated papers, whereas the pretrained model excels in generating well-structured summaries but struggles to cite specific sources. In response, this study introduces RefAI, an innovative retrieval-augmented generative tool designed to synergize the strengths of large language models (LLMs) while overcoming their limitations. Materials and Methods RefAI utilized PubMed for systematic literature retrieval, employed a novel multivariable algorithm for article recommendation, and leveraged GPT-4 turbo for summarization. Ten queries under 2 prevalent topics (“cancer immunotherapy and target therapy” and “LLMs in medicine”) were chosen as use cases and 3 established counterparts (ChatGPT-4, ScholarAI, and Gemini) as our baselines. The evaluation was conducted by 10 domain experts through standard statistical analyses for performance comparison. Results The overall performance of RefAI surpassed that of the baselines across 5 evaluated dimensions—relevance and quality for literature recommendation, accuracy, comprehensiveness, and reference integration for summarization, with the majority exhibiting statistically significant improvements (P-values <.05). Discussion RefAI demonstrated substantial improvements in literature recommendation and summarization over existing tools, addressing issues like fabricated papers, metadata inaccuracies, restricted recommendations, and poor reference integration. Conclusion By augmenting LLM with external resources and a novel ranking algorithm, RefAI is uniquely capable of recommending high-quality literature and generating well-structured summaries, holding the potential to meet the critical needs of biomedical professionals in navigating and synthesizing vast amounts of scientific literature.

Background: Polyamines produced by host cells and intestinal microbiota and are critical to overall health. Studies have shown putrescine, a polyamine, can strengthen, or in some instances disrupt, gastrointestinal (GI) barrier integrity, yet the regulation of polyamine concentrations in the GI tract is unknown. Host colonocytes and microbiota both metabolize polyamines, and in GI diseases like irritable bowel syndrome (IBS) where intestinal microbiota is significantly altered, polyamine metabolism may be affected. Aim: Determine regulation of luminal polyamine concentration and its effects on intestinal barrier integrity. Hypothesis: Luminal polyamine concentration is suppressed by commensal intestinal microbiota and increasing concentration of putrescine results in intestinal barrier disruption. Methods: Microbiota effects on luminal polyamine concentrations were assessed by humanizing germ-free (GF) mice with a single oral gavage of commensal human microbiota. Polyamine effect on barrier integrity was assessed in vitro using Caco-2 cells and ex vivo on Ussing using mouse colonic tissue with 300Da fluorescein and 4kDa FITC-Dextran tracers. Changes in transepithelial resistance (TER) and rate of tracer flux was recorded. Untargeted metabolomics with shotgun metagenomics was completed on human fecal samples and sigmoid colonic biopsies were collected for bulk RNAseq. Bray-Curtis distance was determined at the species level using the PERMANOVA method and used to test relationships between beta-diversity and fecal polyamine concentration. Results: Humanization with human commensal microbiota (1.2% C. aerofaciens) lead to a 20-fold increase in cecal putrescine and a 20-fold decrease in fecal putrescine compared to GF controls. In vitro addition of putrescine (100mM) caused increased fluorescein flux (3.50±0.24 vs 1.44±0.04 mg/mL) and a rapid loss of transepithelial resistance compared to controls (% of Baseline TER, 36.6±8.2 vs 102.8±5.4, 3h postexposure). Ex vivo addition of putrescine caused a loss of TER (57% vs 89% of baseline by 3h) and an increased rate of 4kDa FITC-Dextran flux compared to untreated controls (1236±131 vs 562±70 ng/hr/cm2). Transcriptomic profiles show decreased expression of ornithine decarboxylase antienzyme (OAZ1, FDR=0.018) in IBS which inhibits the rate limiting enzyme for putrescine production. Increased lactulose excretion (2-24h), suggestive of increased distal colonic permeability, correlated with N-acetylputrescine concentration (p=0.07). N-acetylputrescine also correlated positively with increased stool frequency (p=0.009) and looser consistency (p=0.013). C. aerofaciens, a polyamine consumer, negatively correlated with n-acetylputrescine (FDR=0.02) suggesting a loss of specific taxa may lead to insuffcient polyamine metabolism. Conclusion: Polyamines, namely putrescine, disrupts intestinal barrier integrity, correlate with in vivo permeability, and are decreased in the colon by commensal microbiota. These observations identify putrescine as a negative effector of barrier function and suggest a novel role for the commensal microbiome in regulating barrier integrity through polyamine metabolism. Further work investigating host and microbiota mechanisms of polyamine metabolism, signaling and the specific taxa involved is needed to better understand the effects polyamines have on GI physiology. NIH DK 127998 (MG), support from Mayo Clinic Center for Individualized Medicine (CIM), and Mayo Clinic Center for Cell Signalling in Gastroenterology (C-Sig) P30DK084567. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mechanical forces on the airway can contribute to altered contractility and remodeling in airway diseases, but the mechanisms are not clearly understood. Using human airway smooth muscle cells exposed to cyclic forces with static stretch to mimic breathing and static pressure, we found that the effects of stretch are mediated through STIM1, resulting in the activation of multiple pathways, including Piezo channels and the inflammasome, with potential downstream influences on contractility and remodeling.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non–Small Cell Lung Cancer (NSCLC) provide recommendations for the treatment of patients with NSCLC, including diagnosis, primary disease management, surveillance for relapse, and subsequent treatment. The panel has updated the list of recommended targeted therapies based on recent FDA approvals and clinical data. This selection from the NCCN Guidelines for NSCLC focuses on treatment recommendations for advanced or metastatic NSCLC with actionable molecular biomarkers.