Intratumor heterogeneity of EGFR expression mediates targeted therapy resistance and formation of drug tolerant microenvironment.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors are commonly used to treat non-small cell lung cancers with EGFR mutations, but drug resistance often emerges. Intratumor heterogeneity is a known cause of targeted therapy resistance and is considered a major factor in treatment failure. This study identifies clones of EGFR-mutant non-small cell lung tumors expressing low levels of both wild-type and mutant EGFR protein.

Transferrin receptor targeting chimeras for membrane protein degradation.

Cancer cells require high levels of iron for rapid proliferation, leading to significant upregulation of cell-surface transferrin receptor 1 (TfR1), which mediates iron uptake by binding to the iron-carrying protein transferrin. Leveraging this phenomenon and the fast endocytosis rate of TfR1 (refs. ), we developed transferrin receptor targeting chimeras (TransTACs), a heterobispecific antibody modality for membrane protein degradation.

Parsing digital or analog TCR performance through piconewton forces.

αβ T cell receptors (TCRs) principally recognize aberrant peptides bound to major histocompatibility complex molecules (pMHCs) on unhealthy cells, amplifying specificity and sensitivity through physical load placed on the TCR-pMHC bond during immunosurveillance. To understand this mechanobiology, TCRs stimulated by abundantly and sparsely arrayed epitopes (NP/D and PA/D, respectively) following in vivo influenza A virus infection were studied with optical tweezers. While certain NP repertoire CD8 T lymphocytes require many ligands for activation, others are digital, needing just few.

Parsing digital or analogue TCR performance through piconewton forces.

Unlabelled: αβ T-cell receptors (TCRs) recognize aberrant peptides bound to major histocompatibility complex molecules (pMHCs) on unhealthy cells, amplifying specificity and sensitivity through physical load placed on the TCR-pMHC bond during immunosurveillance. To understand this mechanobiology, TCRs stimulated by abundantly and sparsely arrayed epitopes (NP /D and PA /D , respectively) following influenza A virus infection were studied with optical tweezers. While certain NP repertoire CD8 T lymphocytes require many ligands for activation, others are digital, needing just few.

Hepatic loss protects mice from non-alcoholic fatty liver disease through lipid metabolic rewiring.

Non-alcoholic fatty liver disease (NAFLD) is the most pervasive liver pathology worldwide. Here, we demonstrate that the ubiquitin E3 ligase Huwe1 is vital in NAFLD pathogenesis. Using mass spectrometry and RNA sequencing, we reveal that liver-specific deletion of Huwe1 () in 1-year-old mice (approximately middle age in humans) elicits extensive lipid metabolic reprogramming that involves downregulation of lipogenesis and fatty acid uptake, upregulation of fatty acid β-oxidation, and increased oxidative phosphorylation.

Mammalian SWI/SNF chromatin remodeling complexes promote tyrosine kinase inhibitor resistance in EGFR-mutant lung cancer.

Acquired resistance to tyrosine kinase inhibitors (TKI), such as osimertinib used to treat EGFR-mutant lung adenocarcinomas, limits long-term efficacy and is frequently caused by non-genetic mechanisms. Here, we define the chromatin accessibility and gene regulatory signatures of osimertinib sensitive and resistant EGFR-mutant cell and patient-derived models and uncover a role for mammalian SWI/SNF chromatin remodeling complexes in TKI resistance. By profiling mSWI/SNF genome-wide localization, we identify both shared and cancer cell line-specific gene targets underlying the resistant state.

The Role of CD36 in Cancer Progression and Its Value as a Therapeutic Target.

Cluster of differentiation 36 (CD36) is a cell surface scavenger receptor that plays critical roles in many different types of cancer, notably breast, brain, and ovarian cancers. While it is arguably most well-known for its fatty acid uptake functions, it is also involved in regulating cellular adhesion, immune response, and apoptosis depending on the cellular and environmental contexts. Here, we discuss the multifaceted role of CD36 in cancer biology, such as its role in mediating metastasis, drug resistance, and immune evasion to showcase its potential as a therapeutic target.

Immunosuppression reduces rAAV2.5T neutralizing antibodies that limit efficacy following repeat dosing to ferret lungs.

The efficacy of redosing the recombinant adeno-associated virus (rAAV) vector rAAV2.5T to ferret lung is limited by AAV neutralizing antibody (NAb) responses. While immunosuppression strategies have allowed for systemic rAAV repeat dosing, their utility for rAAV lung-directed gene therapy is largely unexplored.

Macrocyclization of Quinazoline-Based EGFR Inhibitors Leads to Exclusive Mutant Selectivity for EGFR L858R and Del19.

Activating mutations in the epidermal growth factor receptor (EGFR) are frequent oncogenic drivers of non-small-cell lung cancer (NSCLC). The most frequent alterations in EGFR are short in-frame deletions in exon 19 (Del19) and the missense mutation L858R, which both lead to increased activity and sensitization of NSCLC to EGFR inhibition. The first approved EGFR inhibitors used for first-line treatment of NSCLC, gefitinib and erlotinib, are quinazoline-based.

An allosteric inhibitor against the therapy-resistant mutant forms of EGFR in non-small cell lung cancer.

Epidermal growth factor receptor (EGFR) therapy using small-molecule tyrosine kinase inhibitors (TKIs) is initially efficacious in patients with EGFR-mutant lung cancer, although drug resistance eventually develops. Allosteric EGFR inhibitors, which bind to a different EGFR site than existing ATP-competitive EGFR TKIs, have been developed as a strategy to overcome therapy-resistant EGFR mutations. Here we identify and characterize JBJ-09-063, a mutant-selective allosteric EGFR inhibitor that is effective across EGFR TKI-sensitive and resistant models, including those with EGFR T790M and C797S mutations.

X-Linked Is Essential for Oocyte Maturation and Preimplantation Embryo Development.

HUWE1 is a HECT-domain ubiquitin E3 ligase expressed in various tissues. Although HUWE1 is known to promote degradation of the tumor suppressor p53, given a growing list of its substrates, functions of HUWE1 remain elusive. Here, we investigated the role of HUWE1 in the female reproductive system.

Lipid metabolic reprogramming as an emerging mechanism of resistance to kinase inhibitors in breast cancer.

Breast cancer is one of the leading causes of death in women in the United States. In general, patients with breast cancer undergo surgical resection of the tumor and/or receive drug treatment to kill or suppress the growth of cancer cells. In this regard, small molecule kinase inhibitors serve as an important class of drugs used in clinical and research settings.

CD36: a key mediator of resistance to HER2 inhibitors in breast cancer.

Acquired resistance to anti-HER2 therapy is a significant clinical challenge in breast cancer. We recently discovered that during acquisition of resistance to HER2 inhibition, upregulation of the fatty acid transporter CD36 takes place, playing a key role in metabolic rewiring and resistance to anti-HER2 therapy.

CD36-Mediated Metabolic Rewiring of Breast Cancer Cells Promotes Resistance to HER2-Targeted Therapies.

Although it is established that fatty acid (FA) synthesis supports anabolic growth in cancer, the role of exogenous FA uptake remains elusive. Here we show that, during acquisition of resistance to HER2 inhibition, metabolic rewiring of breast cancer cells favors reliance on exogenous FA uptake over de novo FA synthesis. Through cDNA microarray analysis, we identify the FA transporter CD36 as a critical gene upregulated in cells with acquired resistance to the HER2 inhibitor lapatinib.

Endocytosis of very low-density lipoproteins: an unexpected mechanism for lipid acquisition by breast cancer cells.

We previously described the expression of CD36 and LPL by breast cancer (BC) cells and tissues and the growth-promoting effect of VLDL observed only in the presence of LPL. We now report a model in which LPL is bound to a heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to internalize VLDLs via receptor-mediated endocytosis. We also demonstrate that gene-expression programs for lipid synthesis versus uptake respond robustly to triglyceride-rich lipoprotein availability.

Methods for efficient analysis of tocopherols, tocotrienols and their metabolites in animal samples with HPLC-EC.

Tocopherols and tocotrienols, collectively known as vitamin E, have received a great deal of attention because of their interesting biological activities. In the present study, we reexamined and improved previous methods of sample preparation and the conditions of high-performance liquid chromatography for more accurate quantification of tocopherols, tocotrienols and their major chain-degradation metabolites. For the analysis of serum tocopherols/tocotrienols, we reconfirmed our method of mixing serum with ethanol followed by hexane extraction.

Epicardial Tachosil Patch Repair of Ventricular Rupture in a 90-Year-Old After Mitral Valve Replacement.

We report our experience with emergent treatment of ventricular rupture following a mitral valve replacement in a 90 year-old male. The repair was performed using a Tachosil patch (Baxter Health Care Corporation, Westlake Village, California), a fibrin sealant coated on an equine collagen sponge, and BioGlue (Cryolife, Kenneson, GA) and bovine pericardium (Edwards Lifesciences, Irvine, CA). Aside from early ventricular dysfunction requiring a low-dose dopamine infusion, this patient's recovery was uneventful.

Long-term survival after use of internal thoracic artery in octogenarians is gender related.

Objective: The goal of this study is to assess the benefits of a left internal thoracic artery as a bypass conduit in octogenarians undergoing elective coronary artery bypass grafting. We hypothesize that there is no survival advantage and that outcome may be gender related.

Methods: In a retrospective analysis of 1141 octogenarians (aged >80 years) undergoing isolated coronary artery bypass grafting from 1996 to 2012, patients were divided into 2 groups: Group I (coronary artery bypass grafting-left internal thoracic artery) included 870 patients (339 female/531 male), and group II (coronary artery bypass grafting-saphenous vein graft) included 271 patients (131 female/140 male).

Midterm outcomes of patients undergoing aortic valve replacement after previous coronary artery bypass grafting.

Objectives: Redo cardiac surgery for aortic valve replacement (AVR) after previous coronary artery bypass grafting (CABG) is technically challenging and carries a high incidence of peri-operative complications. However, experience in the field continues to evolve generating reproducible, and increasingly safer results. We anticipate an increased future role for catheter-based valve procedures and review our operative results to maintain current surgical outcomes for comparison.

Impaired contractile response of human peripheral arterioles to thromboxane A-2 after cardiopulmonary bypass.

Background: We studied the contractile response of human peripheral microvasculature to thromboxane A-2 (TXA-2) before and after cardiopulmonary bypass (CPB), with and without the blockade of TXA-2 receptors, or the inhibition of phospholipase C (PLC), phospholipase A-2 (PLA-2) or protein kinase C (PKC)-α. We also examined the protein/gene expression and localization of TXA-2 receptors, TXA-2 synthase, PLC, and other TXA-2-related proteins.

Methods: Skeletal muscle arterioles (90-180 μm in diameter) were harvested pre- and post-CPB from patients (n = 28) undergoing cardiac surgery.

Redo sternotomy for cardiac reoperations using peripheral heparin-bonded cardiopulmonary bypass circuits without systemic heparinization: technique and results.

Objective: Cardiac reoperations are challenging and time-consuming and incur a high incidence of perioperative complications because of injuries to cardiac structures, bleeding, and hemodynamic instability. Some centers are using extracorporeal circulation with heparinization at the time of resternotomy, but it leads to prolonged anticoagulation, platelet dysfunction, fibrinolysis, coagulopathy, and morbidity. The authors routinely perform resternotomy in complex surgery with the support of heparinless cardiopulmonary bypass with heparin-bonded circuits (HBCs).

Mycotic ascending aortic pseudoaneurysm secondary to pseudomonas mediastinitis at the aortic cannulation site.

During the last 5 years, postoperative Pseudomonas mediastinitis has occurred in 2 of the 3,072 patients in our institution who have undergone cardiopulmonary bypass cardiac operations via a sternotomy. To our knowledge, there is no prior report in the English-language literature of postoperative Pseudomonas mediastinitis that originated at the aortic cannulation site, yet that was the site of origin in both of these patients. The 1st patient developed a mycotic pseudoaneurysm of the ascending aorta at the cannulation site, secondary to the development of Pseudomonas mediastinitis following aortic valve replacement.