Citations

Abstract This study delineates a novel multisystem caliber-persistent arteriopathy syndrome, fundamentally redefining the classical Dieulafoy's lesion from a localized gastrointestinal anomaly to a systemic congenital vasculopathy. Through integrated histopathological and genomic analysis of a forensic autopsy case, we identified pervasive arterial remodeling across seven organ systems— characterized by absent physiological tapering— indicating developmental angiogenic dysregulation. Whole-genome sequencing uncovered pathogenic variants in PDE8B , LRCH1 , and ADA genes, with functional enrichment analyses implicating dysregulated purine–cAMP signaling and cytoskeletal organization as core pathogenic mechanisms. These findings establish a genetic basis for the observed pan-vascular phenotype and highlight the necessity of systematic vascular screening in cases of unexplained multiorgan hemorrhage. This work provides a foundational framework for diagnosing and investigating congenital vascular malformations with hemorrhagic risk, urging a paradigm shift in clinical evaluation and etiological assessment.

Abstract INTRODUCTION While cardiac comorbidities or factors predisposing infection are common in patients with ESRD, one less common cause for pleural effusion in peritoneal dialysis (PD) patients is pleuroperitoneal communication. We present herein a case of a PD patient with large, right-sided pleural effusion one year after starting PD. CASE REPORT An 82-year-old female with ESRD managed on home continuous cycling peritoneal dialysis (CCPD) for 1 year presented to the Emergency Department (ED) with new-onset dyspnea. She recently completed a course of vancomycin for bacterial peritonitis secondary to PD catheter infection. She also reported that her home CCPD machine was not draining the fill amount in recent weeks. She was afebrile and hemodynamically stable on arrival. CT at the ED showed a large, right-sided pleural effusion. She underwent thoracentesis with pending fluid analysis, and experienced subsequent improvement in her dyspnea. She was then hospitalized and wished to continue PD over pursuing intermittent hemodialysis (iHD) while workup was pending, despite clinical suspicion for pleuroperitoneal fistula (PPF). She started inpatient CCPD, and drains following each dwell showed less than expected volumes with no additional output on manual drains. She reported worsening dyspnea the next morning, and bedside POCUS confirmed reaccumulation of her pleural effusion. Fluid analysis revealed a transudative pleural fluid profile, with pleural glucose of 583mg/dL and serum glucose of 80mg/dL. Given her recent peritonitis, suspicion was greatest for PPF. The patient was transitioned from PD to iHD to allow time for the suspected fistula to heal, and subsequent imaging obtained during her hospitalization did not show reaccumulation of her unilateral pleural effusion. DISCUSSION Pleuroperitoneal communication may occur due to congenital or acquired diaphagmatic defects, or insults such as the case in our patient with recent peritonitis. In fact, diaphragmatic blebs from age related degeneration and chronic increased intraabdominal pressure have been reported to cause hydrothorax in patients undergoing PD. Diagnosis of PD-associated pleural effusions is based on clinical suspicion, with pleural studies showing high pleural fluid to serum glucose gradient, and imaging commonly showing unilateral right-sided pleural effusions. Recent peritoneal dialysis with low drainage further supports PD as the etiology. Most cases of PD-associated pleural effusions occur soon after PD initiation, but cases occurring years after initiation have been reported. Management involves halting PD and thoracentesis for symptomatic relief. Patients may need transitioning to iHD indefinitely, or may resume PD after a pause if the cause of communication is reversible.

Background: Static ice storage (SIS) has long been accepted as the conventional lung preservation method, assuming to maintain 4 °C temperature. Although never directly confirmed by temperature measurements, this assumption has been widely accepted. We aimed to measure lung and preservation temperature with SIS in porcine experiments and clinical observations. Methods: Porcine lungs were preserved with SIS for 8 h (group I, n = 3) and 3 h followed by 10 °C storage (group II, n = 3). Tissue (tissueT°), first bag preservation solution (psT°) and second bag saline (salineT°) temperature were monitored. In clinical lungs (n = 4), psT° was monitored during SIS. Surface (surfaceT°) and core (coreT°) temperature were assessed before and after SIS (n = 62). Results: After 4 h in porcine lung group I, average tissueT° was 0.66 °C, psT° was 0.12 °C and salineT° was −0.02 °C. After 3 h in group II, average tissueT° was 1.90 °C, psT° was 0.57 °C and salineT° was 2.33 °C. In clinical observations, psT° was below 4 °C after 9–13 min and 0 °C after 78–267 min. After SIS, median surfaceT° was 1.25 °C (min-max; −3.2–9.2 °C) and coreT° was 1.45 °C (−0.4–4.8 °C). Conclusions: SIS leads to rapid temperature drops below 4 °C, approaching 0 °C within 2–4 h. The post-SIS lung temperature shows considerable variability and does not consistently remain at the commonly assumed 4 °C, posing potential freezing injury to donor lungs.

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 Retinoblastoma (RB) protein can exert tumor suppressor functions even when it becomes phosphorylated. It is thus essential to understand how phosphorylated RB (p-RB) expression and function are regulated. Here, we demonstrated that RING finger domain protein TRIM28 bound and promoted ubiquitination and degradation of CDK4/6-phosphorylated RB protein. SETDB1, a known TRIM28 binding partner, protected p-RB from degradation through the binding of methylated RB by its Tudor domain independent of its methyltransferase activity. SETDB1 was found to be frequently overexpressed due to gene amplification and positively correlated with p-RB in prostate cancer patient specimens. Inhibition of SETDB1 expression using a gene-specific antisense oligonucleotide (ASO) reduced tumor growth but accelerated RB protein degradation, limiting the therapeutic efficacy. However, coadministration of the CDK4/6 inhibitor palbociclib blocked ASO-induced RB degradation and resulted in a much greater cancer-inhibitory effect than each inhibitor alone both in vitro and in vivo. This study identified CDK4/6-dependent, TRIM28-mediated proteasomal degradation as a mechanism of RB inactivation and reveals SETDB1 as a key inhibitor of this process. Our findings suggest that combined targeting of SETDB1 and CDK4/6 represents a viable approach for the treatment of cancers with SETDB1 gene amplification or overexpression. Significance: The identification of a role for TRIM28 and SETDB1 in regulating CDK4/6-phosphorylated RB stability uncovers a combination strategy using CDK4/6 and SETDB1 inhibition to decrease RB degradation and inhibit cancer growth.

Abstract The tumor-suppressor protein RB acts as a transcription repressor via interaction of its pocket domain with an LXCXE motif in histone deacetylase (HDAC) proteins such as HDAC1. Here, we demonstrate that HDAC5 deficient for the LXCXE motif interacts with both RB-N (via an FXXXV motif) and RB-C segments, and such interactions are diminished by phosphorylation of RB serine-249/threonine-252 and threonine-821. HDAC5 was frequently downregulated or deleted in human cancers such as prostate cancer. Loss of HDAC5 increased histone H3 lysine 27 acetylation (H3K27-ac) and circumvented RB-mediated repression of cell-cycle–related pro-oncogenic genes. HDAC5 loss also conferred resistance to CDK4/6 inhibitors such as palbociclib in prostate and breast cancer cells in vitro and prostate tumors in vivo, but this effect was overcome by the BET-CBP/p300 dual inhibitor NEO2734. Our findings reveal an unknown role of HDAC5 in RB-mediated histone deacetylation and gene repression and define a new mechanism modulating CDK4/6 inhibitor therapeutic sensitivity in cancer cells. Significance: This study defines a previously uncharacterized role of HDAC5 in tumor suppression and provides a viable strategy to overcome CDK4/6 inhibitor resistance in HDAC5-deficent cancer.

The prevalence of Lynch syndrome (LS) varies significantly in different populations, suggesting that ethnic features might play an important role. We enrolled 3330 consecutive Chinese patients who had surgical resection for newly diagnosed colorectal cancer. Universal screening for LS was implemented, including immunohistochemistry for mismatch repair (MMR) proteins, BRAFV600E mutation test and germline sequencing. Among the 3250 eligible patients, MMR protein deficiency (dMMR) was detected in 330 (10.2%) patients. Ninety‐three patients (2.9%) were diagnosed with LS. Nine (9.7%) patients with LS fulfilled Amsterdam criteria II and 76 (81.7%) met the revised Bethesda guidelines. Only 15 (9.7%) patients with absence of MLH1 on IHC had BRAFV600E mutation. One third (33/99) of the MMR gene mutations have not been reported previously. The age of onset indicates risk of LS in patients with dMMR tumors. For patients older than 65 years, only 2 patients (5.7%) fulfilling revised Bethesda guidelines were diagnosed with LS. Selective sequencing of all cases with dMMR diagnosed at or below age 65 years and only of those dMMR cases older than 65 years who fulfill revised Bethesda guidelines results in 8.2% fewer cases requiring germline testing without missing any LS diagnoses. While the prevalence of LS in Chinese patients is similar to that of Western populations, the spectrum of constitutional mutations and frequency of BRAFV600E mutation is different. Patients older than 65 years who do not meet the revised Bethesda guidelines have a low risk of LS, suggesting germline sequencing might not be necessary in this population.

Abstract Dysregulation of the MAPK pathway correlates with progression of pancreatic ductal adenocarcinoma (PDAC) progression. IQ motif containing GTPase-activating protein 1 (IQGAP1) is a MAPK scaffold that directly regulates the activation of RAF, MEK, and ERK. Fructose-1,6-bisphosphatase (FBP1), a key enzyme in gluconeogenesis, is transcriptionally downregulated in various cancers, including PDAC. Here, we demonstrate that FBP1 acts as a negative modulator of the IQGAP1–MAPK signaling axis in PDAC cells. FBP1 binding to the WW domain of IQGAP1 impeded IQGAP1-dependent ERK1/2 phosphorylation (pERK1/2) in a manner independent of FBP1 enzymatic activity. Conversely, decreased FBP1 expression induced pERK1/2 levels in PDAC cell lines and correlated with increased pERK1/2 levels in patient specimens. Treatment with gemcitabine caused undesirable activation of ERK1/2 in PDAC cells, but cotreatment with the FBP1-derived small peptide inhibitor FBP1 E4 overcame gemcitabine-induced ERK activation, thereby increasing the anticancer efficacy of gemcitabine in PDAC. These findings identify a primary mechanism of resistance of PDAC to standard therapy and suggest that the FBP1–IQGAP1–ERK1/2 signaling axis can be targeted for effective treatment of PDAC. Cancer Res; 77(16); 4328–41. ©2017 AACR.