Regorafenib induces DNA damage and enhances PARP inhibitor efficacy in pancreatic ductal carcinoma.

Background: There is increasing interest in enhancing the response of the PARP inhibitor olaparib, which is currently approved for pancreatic ductal adenocarcinoma (PDAC) patients with defects in DNA damage repair associated with germline BRCA1/2 mutations. Moreover, agents that can mimic these defects in the absence of germline BRCA1/2 mutations are an area of active research in hopes of increasing the number of patients eligible for treatment with PARP inhibitors. The extent to which regorafenib, an FDA-approved tyrosine kinase inhibitor, can be used to enhance the efficacy of PARP inhibitors in PDAC cells without known BRCA1/2 mutations remains to be investigated.

Trametinib Potentiates Anti-PD-1 Efficacy in Tumors Established from Chemotherapy-Primed Pancreatic Cancer Cells.

Despite advances in immune checkpoint inhibitors, chemotherapy remains the standard therapy for patients with pancreatic ductal adenocarcinoma (PDAC). As the combinations of chemotherapy, including the FOLFIRINOX [5-fluorouracil, F; irinotecan, I; and oxaliplatin, O (FIO)] regimen, and immune checkpoint inhibitors have failed to demonstrate clinical benefit in patients with metastatic PDAC tumors, there is increasing interest in identifying therapeutic approaches to potentiate ICI efficacy in patients with PDAC. In this study, we report that neoadjuvant FOLFIRINOX-treated human PDAC tumors exhibit increased MEK/ERK activation.

Targeting BCL2 with Venetoclax Enhances the Efficacy of the KRASG12D Inhibitor MRTX1133 in Pancreatic Cancer.

MRTX1133 is currently being evaluated in patients with pancreatic ductal adenocarcinoma (PDAC) tumors harboring a KRASG12D mutation. Combination strategies have the potential to enhance the efficacy of MRTX1133 to further promote cell death and tumor regression. In this study, we demonstrated that MRTX1133 increased the levels of the proapoptotic protein BIM in PDAC cells and conferred sensitivity to the FDA-approved BCL2 inhibitor venetoclax.

Chromium (VI) promotes lung cancer initiation by activating EGF/ALDH1A1 signalling.

Lung cancer is the leading cause of cancer-related death worldwide and is strongly associated with tobacco smoke exposure. Though smoking remains the most important and best studied risk factor, recent data suggests that several other carcinogens have a driving role in lung cancer development, particularly in select populations at risk of high or prolonged exposure. Hexavalent chromium [Cr(VI)] is a known carcinogen that is widely used in the manufacturing industry.

Non-small cell lung carcinoma spheroid models in agarose microwells for drug response studies.

There is a growing interest in developing personalized treatment strategies for each cancer patient, especially those with non-small cell lung carcinoma (NSCLC) which annually accounts for the majority of cancer related deaths in the US. Yet identifying the optimal NSCLC treatment strategy for each cancer patient is critical due to a multitude of mutations, some of which develop following initial therapy and can result in drug resistance. A key difficulty in developing personalized therapies in NSCLC is the lack of clinically relevant assay systems that are suitable to evaluate drug sensitivity using a minuscule amount of patient-derived material available following biopsies.

Three Birds, One Excipient: Development of an Improved pH, Isotonic, and Buffered Ketamine Formulation for Subcutaneous Injection.

Subcutaneous (SC) ketamine has been found to be effective in pain management, though reports of injection site irritation and sterile abscesses exist with currently available ketamine HCl formulations. Such adverse SC reactions are commonly associated with low pH, high osmolality and/or high injection volumes. An optimal SC formulation of ketamine would thus have a pH and osmolality close to physiological levels, without compromising on concentration and, thus, injection volume.

Newborn Pulse Oximetry Screening at a Community Hospital: An 8-Year Experience.

Objectives: To evaluate newborn pulse oximetry screening (POS) outcomes at a large community hospital and the impact of the recommended revised POS algorithm.

Methods: A retrospective cohort study was performed to evaluate the results of POS in the well-infant nursery between 2012 and 2020. The POS results were obtained from an electronic platform.

A Paradigm for Peptide Hormone-GPCR Analyses.

Work from our laboratories over the last 35 years that has focused on Ste2p, a G protein-coupled receptor (GPCR), and its tridecapeptide ligand α-factor is reviewed. Our work utilized the yeast as a model system for understanding peptide-GPCR interactions. It explored the structure and function of synthetic α-factor analogs and biosynthetic receptor domains, as well as designed mutations of Ste2p.

Endothelin-1-Mediated Drug Resistance in -Mutant Non-Small Cell Lung Carcinoma.

Progression on therapy in non-small cell lung carcinoma (NSCLC) is often evaluated radiographically, however, image-based evaluation of said therapies may not distinguish disease progression due to intrinsic tumor drug resistance or inefficient tumor penetration of the drugs. Here we report that the inhibition of mutated promotes the secretion of a potent vasoconstrictor, endothelin-1 (EDN1), which continues to increase as the cells become resistant with a mesenchymal phenotype. As EDN1 and its receptor (EDNR) is linked to cancer progression, EDNR-antagonists have been evaluated in several clinical trials with disappointing results.

Transforming Nursing Education Through Interprofessional Collaborative Innovation: A Project Story.

This project story is about transforming nursing education through interprofessional collaborative innovation to develop and use a complement of technology-based portable simulation devices collectively known as the Healthcare Education Simulation Station. This collection of inexpensive, simulated point-of-care instruments controlled wirelessly by an instructor or simulation operator were developed and field tested by an interdisciplinary team to enhance learning experiences in several configurations, including those using standardized patients and those using static and low-, mid-, and high-fidelity manikins. The core feature of this project story is the collaboration of students and faculty from two unrelated disciplines, nursing and engineering.

THE USE OF CITALOPRAM HYDROBROMIDE TO MANAGE AGGRESSION IN A MALE CHIMPANZEE ().

At times severe, and occasionally fatal, aggression plays an intrinsic role in chimpanzee behavior and social dynamics, particularly among male chimpanzees in both managed and free-ranging troops. At the Los Angeles Zoo, one adult male's natural aggressive behavior developed into unmanageable violence during a period of social and emotional instability consequent to the lack of an established alpha male in the colony. The severity and duration of resulting attacks on a subdominant member of the community, despite environmental and behavioral modification, indicated the need for psychopharmaceutical intervention.

CXCR7 Reactivates ERK Signaling to Promote Resistance to EGFR Kinase Inhibitors in NSCLC.

Although EGFR mutant-selective tyrosine kinase inhibitors (TKI) are clinically effective, acquired resistance can occur by reactivating ERK. We show using models of acquired EGFR TKI resistance with a mesenchymal phenotype that CXCR7, an atypical G protein-coupled receptor, activates the MAPK-ERK pathway via β-arrestin. Depletion of CXCR7 inhibited the MAPK pathway, significantly attenuated EGFR TKI resistance, and resulted in mesenchymal-to-epithelial transition.

UV Laser-Induced, Time-Resolved Transcriptome Responses of .

We determined the effect on gene transcription of laser-mediated, long-wavelength UV-irradiation of by RNAseq analysis at times T15, T30, and T60 min after recovery in growth medium. Laser-irradiated cells were viable, and the transcriptional response was transient, with over 400 genes differentially expressed at T15 or T30, returning to basal level transcription by T60. Identification of transcripts exhibiting enhanced differential expression that were unique to UV laser-irradiation were identified by imposing a stringent significance cut-off ( < 0.

a-Factor Analogues Containing Alkyne- and Azide-Functionalized Isoprenoids Are Efficiently Enzymatically Processed and Retain Wild-Type Bioactivity.

Protein prenylation is a post-translational modification that involves the addition of one or two isoprenoid groups to the C-terminus of selected proteins using either farnesyl diphosphate or geranylgeranyl diphosphate. Three crucial enzymatic steps are involved in the processing of prenylated proteins to yield the final mature product. The farnesylated dodecapeptide, a-factor, is particularly useful for studies of protein prenylation because it requires the identical three-step process to generate the same C-terminal farnesylated cysteine methyl ester substructure present in larger farnesylated proteins.

Uptake Assay for Radiolabeled Peptides in Yeast.

We describe an assay for measuring the uptake of radioactive peptides into the yeast . The methods presented here can be adapted to measure a variety of substrates transported into any bacterial or fungal cell via specific carrier-mediated systems.

Identification of peptide-binding sites within BSA using rapid, laser-induced covalent cross-linking combined with high-performance mass spectrometry.

We are developing a rapid, time-resolved method using laser-activated cross-linking to capture protein-peptide interactions as a means to interrogate the interaction of serum proteins as delivery systems for peptides and other molecules. A model system was established to investigate the interactions between bovine serum albumin (BSA) and 2 peptides, the tridecapeptide budding-yeast mating pheromone (α-factor) and the decapeptide human gonadotropin-releasing hormone (GnRH). Cross-linking of α-factor, using a biotinylated, photoactivatable p-benzoyl-L-phenylalanine (Bpa)-modified analog, was energy-dependent and achieved within seconds of laser irradiation.

GPCR-Gα protein precoupling: Interaction between Ste2p, a yeast GPCR, and Gpa1p, its Gα protein, is formed before ligand binding via the Ste2p C-terminal domain and the Gpa1p N-terminal domain.

G protein coupled receptors bind ligands that initiate intracellular signaling cascades via heterotrimeric G proteins. In this study, involvement of the N-terminal residues of yeast G-alpha (Gpa1p) with the C-terminal residues of a full-length or C-terminally truncated Ste2p were investigated using bioluminescence resonance energy transfer (BRET), a non-radiative energy transfer phenomenon where protein-protein interactions can be quantified between a donor bioluminescent molecule and a suitable acceptor fluorophore. Constitutive and position-dependent BRET signal was observed in the absence of agonist (α-factor).

Dynamic roles for the N-terminus of the yeast G protein-coupled receptor Ste2p.

The Saccharomyces cerevisiae α-factor receptor Ste2p has been used extensively as a model to understand the molecular mechanism of signal transduction by G protein-coupled receptors (GPCRs). Single and double cysteine mutants of Ste2p were created and served as surrogates to detect intramolecular interactions and dimerization of Ste2p using disulfide cross-linking methodology. When a mutation was introduced into the phylogenetically conserved tyrosine residue at position 26 (Y26C) in the N-terminus of Ste2p, dimerization was increased greatly.

Three-dimensional spatiotemporal tracking of fluorine-18 radiolabeled yeast cells via positron emission particle tracking.

A method for Positron Emission Particle Tracking (PEPT) based on optical feature point identification techniques is demonstrated for use in low activity tracking experiments. A population of yeast cells of approximately 125,000 members is activated to roughly 55 Bq/cell by 18F uptake. An in vitro particle tracking experiment is performed with nearly 20 of these cells after decay to 32 Bq/cell.

Halo Assay for Toxic Peptides and Other Compounds in Microorganisms.

Unlabelled: We describe an assay for determination of toxicity in involving spotting of a toxic peptide on a lawn of yeast cells. This assay may be generalized to determine toxicity of a variety of compounds by substituting a putative toxic compound in place of the peptide. The general protocol may also be used to determine toxicity of any small compound toward another microorganism by replacing with the target microbe and modifying growth conditions accordingly.

The yeast Ste2p G protein-coupled receptor dimerizes on the cell plasma membrane.

Dimerization of G protein-coupled receptors (GPCR) may play an important role in maturation, internalization, signaling and/or pharmacology of these receptors. However, the location where dimerization occurs is still under debate. In our study, variants of Ste2p, a yeast mating pheromone GPCR, were tagged with split EGFP (enhanced green fluorescent protein) fragments inserted between transmembrane domain seven and the C-terminus or appended to the C-terminus.

The N-terminus of the yeast G protein-coupled receptor Ste2p plays critical roles in surface expression, signaling, and negative regulation.

G protein-coupled receptors (GPCRs) are found in all eukaryotic cells examined to date where they function as membrane-bound proteins that bind a multitude of extracellular ligands to initiate intracellular signal transduction systems controlling cellular physiology. GPCRs have seven heptahelical membrane spanning domains connected by extracellular and intracellular loops with an extracellular N-terminus and an intracellular C-terminus. The N-terminus has been the least studied domain of most GPCRs.

Intratumoral Heterogeneity in EGFR-Mutant NSCLC Results in Divergent Resistance Mechanisms in Response to EGFR Tyrosine Kinase Inhibition.

Non-small cell lung cancers (NSCLC) that have developed resistance to EGF receptor (EGFR) tyrosine kinase inhibitor (TKI), including gefitinib and erlotinib, are clinically linked to an epithelial-to-mesenchymal transition (EMT) phenotype. Here, we examined whether modulating EMT maintains the responsiveness of EGFR-mutated NSCLCs to EGFR TKI therapy. Using human NSCLC cell lines harboring mutated EGFR and a transgenic mouse model of lung cancer driven by mutant EGFR (EGFR-Del19-T790M), we demonstrate that EGFR inhibition induces TGFβ secretion followed by SMAD pathway activation, an event that promotes EMT.

Synthesis of Peptides Containing C-Terminal Esters Using Trityl Side-Chain Anchoring: Applications to the Synthesis of C-Terminal Ester Analogs of the Saccharomyces cerevisiae Mating Pheromone a-Factor.

Peptides containing C-terminal esters are an important class of bioactive molecules that includes a-factor, a farnesylated dodecapeptide, involved in the mating of Saccharomyces cerevisiae. Here, results that expand the scope of solid-phase peptide synthetic methodology that uses trityl side-chain anchoring for the preparation of peptides with C-terminal cysteine alkyl esters are described. In this method, Fmoc-protected C-terminal cysteine esters are anchored to trityl chloride resin and extended by standard solid-phase procedures followed by acidolytic cleavage and HPLC purification.