Few therapies are currently available for patients with KRAS-driven cancers, highlighting the need to identify new molecular targets that modulate central downstream effector pathways. Here we found ...that the microRNA (miRNA) cluster including miR181ab1 is a key modulator of KRAS-driven oncogenesis. Ablation of Mir181ab1 in genetically engineered mouse models of Kras-driven lung and pancreatic cancer was deleterious to tumor initiation and progression. Expression of both resident miRNAs in the Mir181ab1 cluster, miR181a1 and miR181b1, was necessary to rescue the Mir181ab1-loss phenotype, underscoring their nonredundant role. In human cancer cells, depletion of miR181ab1 impaired proliferation and 3D growth, whereas overexpression provided a proliferative advantage. Lastly, we unveiled miR181ab1-regulated genes responsible for this phenotype. These studies identified what we believe to be a previously unknown role for miR181ab1 as a potential therapeutic target in 2 highly aggressive and difficult to treat KRAS-mutated cancers.
K-RAS is mutated in approximately 30% of human cancers, resulting in increased RAS signaling and tumor growth. Thus, RAS is a highly validated therapeutic target, especially in tumors of the ...pancreas, lung and colon. Although directly targeting RAS has proven to be challenging, it may be possible to target other proteins involved in RAS signaling, such as the guanine nucleotide exchange factor Son of Sevenless (SOS). We have previously reported on the discovery of small molecules that bind to SOS1, activate SOS-mediated nucleotide exchange on RAS, and paradoxically inhibit ERK phosphorylation (Burns et al., PNAS, 2014). Here, we describe the discovery of additional, structurally diverse small molecules that also bind to SOS1 in the same pocket and elicit similar biological effects. We tested >160,000 compounds in a fluorescence-based assay to assess their effects on SOS-mediated nucleotide exchange. X-Ray structures revealed that these small molecules bind to the CDC25 domain of SOS1. Compounds that elicited high levels of nucleotide exchange activity in vitro increased RAS-GTP levels in cells, and inhibited phospho ERK levels at higher treatment concentrations. The identification of structurally diverse SOS1 binding ligands may assist in the discovery of new molecules designed to target RAS-driven tumors.
•Measured nucleotide exchange rate with a high-throughput fluorescence-based assay.•Discovered structurally diverse molecules that activate nucleotide exchange.•Used X-Ray structures to determine that molecules bind to the CDC25 domain of SOS1.•Identified that molecules modulate RAS-GTP and phospho ERK levels in cancer cells.
OBJECTIVE:To determine whether persistent opioid use after injury is associated with subsequent long-term development of clinically recognized opioid abuse.
SUMMARY BACKGROUND DATA:Opioid abuse is an ...epidemic in the United States and trauma can initiate persistent use; however, it remains unclear whether persistent opioid use contributes to the subsequent development of opioid abuse. The care of combat casualties by the Departments of Defense and Veterans Affairs uniquely allows investigation of this long-term outcome.
METHODS:This retrospective cohort study randomly selected 10,000 battle-injured United States military personnel. We excluded patients who died during initial hospitalization or within 180 days of discharge, had a preinjury opioid abuse diagnosis, or had missing data in a preselected variable. We defined persistent opioid use as filling an opioid prescription 3 to 6 months after discharge and recorded clinically recognized opioid abuse using relevant diagnosis codes.
RESULTS:After exclusion, 9284 subjects were analyzed, 2167 (23.3%) of whom developed persistent opioid use. During a median follow-up time of 8 years, 631 (6.8%) patients developed clinically recognized opioid abuse with a median time to diagnosis of 3 years. Injury severity and discharge opioid prescription amount were associated with persistent opioid use after trauma. After adjusting for patient and injury-specific factors, persistent opioid use was associated with the long-term development of clinically recognized opioid abuse (adjusted hazard ratio, 2.39; 95% confidence interval, 1.99–2.86).
CONCLUSIONS:Nearly a quarter of patients filled an opioid prescription 3 to 6 months after discharge, and this persistent use was associated with long-term development of opioid abuse.
The reliance of many cancers on aerobic glycolysis has stimulated efforts to develop lactate dehydrogenase (LDH) inhibitors. However, despite significant efforts, LDH inhibitors (LDHi) with ...sufficient specificity and in vivo activity to determine whether LDH is a feasible drug target are lacking. We describe an LDHi with potent, on-target, in vivo activity. Using hyperpolarized magnetic resonance spectroscopic imaging (HP-MRSI), we demonstrate in vivo LDH inhibition in two glycolytic cancer models, MIA PaCa-2 and HT29, and we correlate depth and duration of LDH inhibition with direct anti-tumor activity. HP-MRSI also reveals a metabolic rewiring that occurs in vivo within 30 min of LDH inhibition, wherein pyruvate in a tumor is redirected toward mitochondrial metabolism. Using HP-MRSI, we show that inhibition of mitochondrial complex 1 rapidly redirects tumor pyruvate toward lactate. Inhibition of both mitochondrial complex 1 and LDH suppresses metabolic plasticity, causing metabolic quiescence in vitro and tumor growth inhibition in vivo.
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•Specific LDH inhibition in vivo reduces growth rate of glycolytic tumors•Depth and duration of tumor LDH inhibition can be monitored in real time by HP-MRSI•LDH inhibition in vivo redirects pyruvate to support oxidative phosphorylation•Inhibiting mitochondrial complex 1 and LDH enhances durability of anti-tumor response
Oshima et al. use hyperpolarized magnetic resonance spectroscopy to dynamically monitor tumor glycolysis and oxidative phosphorylation. LDH inhibition slows tumor growth but rapidly redirects pyruvate to support mitochondrial metabolism. Inhibiting both mitochondrial complex 1 and LDH suppresses metabolic plasticity of glycolytic tumors in vivo, significantly prolonging tumor growth inhibition.
Abstract Juvenile myelomonocytic leukemia (JMML) is a hematologic malignancy of young children caused by mutations that increase Ras signaling output. Hematopoietic stem cell transplantation (HSCT) ...is a potentially curative treatment, but patients with relapsed or refractory (advanced) disease have dismal outcomes. This phase II trial evaluated the safety and efficacy of trametinib, an oral MEK1/2 inhibitor, in patients with advanced JMML. Ten infants and children were enrolled, and the objective response rate was 50%. Four patients with refractory disease proceeded to HSCT after receiving trametinib. Three additional patients completed all 12 cycles permitted on study and continue to receive off-protocol trametinib without HSCT. The remaining three patients had progressive disease with two demonstrating molecular evolution by the end of cycle 2. Transcriptomic and proteomic analyses provided novel insights into the mechanisms of response and resistance to trametinib in JMML. ClinicalTrials.gov Identifier: NCT03190915. Significance: Trametinib was safe and effective in young children with relapsed or refractory JMML, a lethal disease with poor survival rates. Seven of 10 patients completed the maximum 12 cycles of therapy or used trametinib as a bridge to HSCT and are alive with a median follow-up of 24 months.
Infants diagnosed with acute myeloid leukemia (AML) frequently harbor cytogenetically cryptic fusions involving KMT2A, NUP98 or GLIS2. Those with AML driven specifically by CBFA2T3::GLIS2 fusions ...have a dismal prognosis and are currently risk-stratified to receive hematopoietic stem cell transplantation (HSCT) in first remission. Here we report an infant with AML who was refractory to multiple lines of chemotherapy but lacked an identifiable fusion despite cytogenetic, fluorescence in situ hybridization (FISH) and targeted next generation sequencing (NGS) testing. Research-grade RNASeq from a relapse sample revealed in-frame CBFA2T3::GLIS3 and GLIS3::CBFA2T3 fusions. A patient-derived xenograft (PDX) generated from this patient has a short latency period and represents a strategy to test novel agents that may be effective in this aggressive subtype of AML. This report describes the first case of AML with a CBFA2T3::GLIS3 fusion and highlights the need for unbiased NGS testing including RNASeq at diagnosis, as patients with CBFA2T3::GLIS3 fusions should be considered for HSCT in first remission.
LIM domain kinases 1 and 2 (LIMK1 and LIMK2) regulate actin dynamics and subsequently key cellular functions such as proliferation and migration. LIMK1 and LIMK2 phosphorylate and inactivate cofilin ...leading to increased actin polymerization. As a result, LIMK inhibitors are emerging as a promising treatment strategy for certain cancers and neurological disorders. High-quality chemical probes are required if the role of these kinases in health and disease is to be understood. To that end, we report the results of a comparative assessment of 17 reported LIMK1/2 inhibitors in a variety of in vitro enzymatic and cellular assays. Our evaluation has identified three compounds (TH-257, LIJTF500025, and LIMKi3) as potent and selective inhibitors suitable for use as in vitro and in vivo pharmacological tools for the study of LIMK function in cell biology.
Immediate extubation (IE) following liver transplantation (LT) is increasingly common in adult patients. This study reviews our center's experience with IE in children following LT to determine ...characteristics predictive of successful IE and its effects on post-operative outcomes.
We performed a retrospective chart review of all patients who underwent LT at our institution between January 2005 and November 2022. Patients with concomitant lung transplants and chronic ventilator requirements were excluded.
Overall, 235 patients met study criteria. IE was achieved in 164 (69.8%) patients across all diagnoses and graft types. Of IE patients, only two required re-intubation within 3 days post-transplant. IE patients exhibited significantly shorter ICU (2 1, 3 IQR vs. 4 2, 4 IQR days, p < .001) and hospital lengths of stay (17 12, 24 IQR vs. 22 14, 42 IQR days, p = .001). Pre-transplant ICU requirement, high PELD/MELD score, intraoperative transfusion, cold ischemia time, and pressor requirements were risk factors against IE. There was no association between IE and recipient age or weight. The proportion of patients undergoing IE post-transplant increased significantly over time from 2005 to 2022 (p < .001), underscoring the role of clinical experience and transplant team learning curve.
Spanning 18 years and 235 patients, we report the largest cohort of children undergoing IE following LT. Our findings support that IE is safe across ages and clinical scenarios. As our center gained experience, the rate of IE increased from 40% to 83%. These trends were associated with lower ICU and LOS, the benefits of which include earlier patient mobility and improved resource utilization.
High mobility group box 1 protein (HMGB1) is an alarmin following its release by immune cells upon cellular activation or stress. High levels of extracellular HMGB1 play a critical role in impairing ...the clearance of invading pulmonary pathogens and dying neutrophils in the injured lungs of cystic fibrosis (CF) and acute respiratory distress syndrome (ARDS). A heparin derivative, 2-O, 3-O desulfated heparin (ODSH), has been shown to inhibit HMGB1 release from a macrophage cell line and is efficacious in increasing bacterial clearance in a mouse model of pneumonia. Thus, we hypothesized that ODSH can attenuate the bacterial burden and inflammatory lung injury in CF and we conducted experiments to determine the underlying mechanisms.
We determined the effects of ODSH on lung injury produced by Pseudomonas aeruginosa (PA) infection in CF mice with the transmembrane conductance regulator gene knockout (CFTR
). Mice were given ODSH or normal saline intraperitoneally, followed by the determination of the bacterial load and lung injury in the airways and lung tissues. ODSH binding to HMGB1 was determined using surface plasmon resonance and in silico docking analysis of the interaction of the pentasaccharide form of ODSH with HMGB1.
CF mice given 25 mg/kg i.p. of ODSH had significantly lower PA-induced lung injury compared to mice given vehicle alone. The CF mice infected with PA had decreased levels of nitric oxide (NO), increased levels of airway HMGB1 and HMGB1-impaired macrophage phagocytic function. ODSH partially attenuated the PA-induced alteration in the levels of NO and airway HMGB1 in CF mice. In addition, ODSH reversed HMGB1-impaired macrophage phagocytic function. These effects of ODSH subsequently decreased the bacterial burden in the CF lungs. In a surface plasmon resonance assay, ODSH interacted with HMGB1 with high affinity (K
= 3.89 × 10
M) and induced conformational changes that may decrease HMGB1's binding to its membrane receptors, thus attenuating HMGB1-induced macrophage dysfunction.
The results suggest that ODSH can significantly decrease bacterial infection-induced lung injury in CF mice by decreasing both HMGB1-mediated impairment of macrophage function and the interaction of HMGB1 with membrane receptors. Thus, ODSH could represent a novel approach for treating CF and ARDS patients that have HMGB1-mediated lung injury.
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