Jie Feng

Oncogenic KRAS is a major driver in lung adenocarcinoma (LUAD) that has yet to be therapeutically conquered. Here we report that the SLC7A11/glutathione axis displays metabolic synthetic lethality with oncogenic KRAS. Through metabolomics approaches, we found that mutationally activated KRAS strikingly increased intracellular cystine levels and glutathione biosynthesis. SLC7A11, a cystine/glutamate antiporter conferring specificity for cystine uptake, was overexpressed in patients with KRAS-mutant LUAD and showed positive association with tumor progression. Furthermore, SLC7A11 inhibition by either genetic depletion or pharmacological inhibition with sulfasalazine resulted in selective killing across a panel of KRAS-mutant cancer cells in vitro and tumor growth inhibition in vivo, suggesting the functionality and specificity of SLC7A11 as a therapeutic target. Importantly, we further identified a potent SLC7A11 inhibitor, HG106, that markedly decreased cystine uptake and intracellular glutathione biosynthesis. Furthermore, HG106 exhibited selective cytotoxicity toward KRAS-mutant cells by increasing oxidative stress- and ER stress-mediated cell apoptosis. Of note, treatment of KRAS-mutant LUAD with HG106 in several preclinical lung cancer mouse models led to marked tumor suppression and prolonged survival. Overall, our findings reveal that KRAS-mutant LUAD cells are vulnerable to SLC7A11 inhibition, offering potential therapeutic approaches for this currently incurable disease.

Chronic inflammation induced by endotoxin from a dysbiotic gut microbiota contributes to the development of obesity-related metabolic disorders. Modification of gut microbiota by a diet to balance its composition becomes a promising strategy to help manage obesity. A dietary scheme based on whole grains, traditional Chinese medicinal foods, and prebiotics (WTP diet) was designed to meet human nutritional needs as well as balance the gut microbiota. Ninety-three of 123 central obese volunteers (BMI ≥ 28 kg m(-2) ) completed a self-controlled clinical trial consisting of 9-week intervention on WTP diet followed by a 14-week maintenance period. The average weight loss reached 5.79 ± 4.64 kg (6.62 ± 4.94%), in addition to improvement in insulin sensitivity, lipid profiles, and blood pressure. Pyrosequencing of fecal samples showed that phylotypes related to endotoxin-producing opportunistic pathogens of Enterobacteriaceae and Desulfovibrionaceae were reduced significantly, while those related to gut barrier-protecting bacteria of Bifidobacteriaceae increased. Gut permeability, measured as lactulose/mannitol ratio, was decreased compared with the baseline. Plasma endotoxin load as lipopolysaccharide-binding protein was also significantly reduced, with concomitant decrease in tumor necrosis factor-α, interleukin-6, and an increase in adiponectin. These results suggest that modulation of the gut microbiota via dietary intervention may enhance the intestinal barrier integrity, reduce circulating antigen load, and ultimately ameliorate the inflammation and metabolic phenotypes.

OBJECTIVE: Hepatocellular carcinoma (HCC) is heterogeneous, especially in multifocal tumours, which decreases the efficacy of clinical treatments. Understanding tumour heterogeneity is critical when developing novel treatment strategies. However, a comprehensive investigation of tumour heterogeneity in HCC is lacking, and the available evidence regarding tumour heterogeneity has not led to improvements in clinical practice. DESIGN: We harvested 42 samples from eight HCC patients and evaluated tumour heterogeneity using whole-exome sequencing, RNA sequencing, mass spectrometry-based proteomics and metabolomics, cytometry by time-of-flight, and single-cell analysis. Immunohistochemistry and quantitative polymerase chain reactions were performed to confirm the expression levels of genes. Three independent cohorts were further used to validate the findings. RESULTS: Tumour heterogeneity is considerable with regard to the genomes, transcriptomes, proteomes, and metabolomes of lesions and tumours. The immune status of the HCC microenvironment was relatively less heterogenous. Targeting local immunity could be a suitable intervention with balanced precision and practicability. By clustering immune cells in the HCC microenvironment, we identified three distinctive HCC subtypes with immunocompetent, immunodeficient, and immunosuppressive features. We further revealed the specific metabolic features and cytokine/chemokine expression levels of the different subtypes. Determining the expression levels of CD45 and Foxp3 using immunohistochemistry facilitated the correct classification of HCC patients and the prediction of their prognosis. CONCLUSION: There is comprehensive intratumoral and intertumoral heterogeneity in all dimensions of HCC. Based on the results, we propose a novel immunophenotypic classification of HCCs that facilitates prognostic prediction and may support decision making with regard to the choice of therapy.

Background: A key cause of the high mortality of cardiovascular diseases is the cardiomyocyte inability to renew after cardiac injury. As a promising strategy to supplement functional myocytes for cardiac repair, there is a pressing need to understand the cellular and molecular mechanisms of heart regeneration. Methods: Seven genetic mouse lines were used: global OSM (oncostatin M) knockout, monocyte-/macrophage-specific OSM deletion, cardiomyocyte-specific lines, including OSM receptor deletion, gp130 (glycoprotein 130) deletion, gp130 activation, and Yap (yes-associated protein) ablation with gp130 activation mice. A series of molecular signaling experiments, including RNA sequencing, immunostaining, coimmunoprecipitation, and imaging flow cytometry, were conducted. Two models of cardiac injury, apical resection and myocardial infarction operation, were performed in neonatal, juvenile, and adult mice. Heart regeneration and cardiac function were evaluated by Masson staining and echocardiography, respectively. Gene recombinant adenovirus-associated virus was constructed and infected myocardial-infarcted mice as a gene therapy. Results: OSM was identified by RNA sequencing as a key upstream regulator of cardiomyocyte proliferation during neonatal heart regeneration in mice. Cardiomyocyte proliferation and heart regeneration were suspended in neonatal mice after cardiac injury when OSM was conditionally knockout in macrophages. The cardiomyocyte-specific deficiency of the OSM receptor heterodimers, OSM receptor and gp130, individually in cardiomyocytes reduced myocyte proliferation and neonatal heart regeneration. Conditional activation of gp130 in cardiomyocytes promoted cardiomyocyte proliferation and heart regeneration in juvenile and adult mice. Using RNA sequencing and functional screening, we found that Src mediated gp130-triggered cardiomyocyte proliferation by activating Yap (yes-associated protein) with Y357 phosphorylation independently of the Hippo pathway. Cardiomyocyte-specific deletion of Yap in Myh6-gp130 ACT mice blocked the effect of gp130 activation–induced heart regeneration in juvenile mice. Gene therapy with adenovirus-associated virus encoding constitutively activated gp130 promoted cardiomyocyte proliferation and heart regeneration in adult mice after myocardial infarction. Conclusions: Macrophage recruitment is essential for heart regeneration through the secretion of OSM, which promotes cardiomyocyte proliferation. As the coreceptor of OSM, gp130 activation is sufficient to promote cardiomyocyte proliferation by activating Yap through Src during heart regeneration. gp130 is a potential therapeutic target to improve heart regeneration after cardiac injury.