mTORC1-driven protein translation correlates with clinical benefit of capivasertib within a genetically preselected cohort of PIK3CA-altered tumours.

Capivasertib is a potent selective inhibitor of AKT. It was recently FDA-approved in combination with fulvestrant to treat HR+, HER2-negative breast cancers with certain genetic alteration(s) activating the PI3K pathway. In Phase I trials, heavily pre-treated patients with tumours selected for activating PI3K pathway mutations treated with capivasertib monotherapy demonstrated objective response rates of <30%. We investigated the proteomic profile associated with capivasertib response in genetically pre-selected patients and cancer cell lines. We analyzed samples from 16 PIK3CA-mutated patient tumours collected prior to capivasertib monotherapy in the Phase I trial. PI3K pathway proteins were precisely quantified with immuno-MALDI-MS. Global proteomic profiles were also obtained. Patients were classified according to response to capivasertib monotherapy: "clinical benefit (CB)" (≥12 weeks without progression, n=7) or "no clinical benefit (NCB)" (progression in <12 weeks, n=9). Proteins that differed between the patient groups were subsequently quantified in AKT1- or PIK3CA-altered breast cancer cell lines with varying capivasertib sensitivity. The measured concentrations of AKT1 and AKT2 varied among the PIK3CA-mutated tumours but did not differ between the CB and NCB groups. However, analysis of the global proteome data showed that translational activity was higher in tumours of the NCB vs. CB group. When reproducibly quantified by validated LC-MRM-MS assays, the same proteins of interest similarly distinguished between capivasertib-sensitive vs. -resistant cell lines. The results provide further evidence that increased mTORC1-driven translation functions as a mechanism of resistance to capivasertib monotherapy. Protein concentrations may offer additional insights for patient selection for capivasertib, even among genetically pre-selected patients.

A multiplexed, automated immuno-matrix assisted laser desorption/ionization mass spectrometry assay for simultaneous and precise quantitation of PTEN and p110α in cell lines and tumor tissues.

The PI3-kinase/AKT/mTOR pathway plays a central role in cancer signaling. While p110α is the catalytic α-subunit of PI3-kinase and a major drug target, PTEN is the main negative regulator of the PI3-kinase/AKT/mTOR pathway. PTEN is often down-regulated in cancer, and there are conflicting data on PTEN's role as breast cancer biomarker. PTEN and p110α protein expression in tumors is commonly analyzed by immunohistochemistry, which suffers from poor multiplexing capacity, poor standardization, and antibody crossreactivity, and which provides only semi-quantitative data. Here, we present an automated, and standardized immuno-matrix-assisted laser desorption/ionization mass spectrometry (iMALDI) assay that allows precise and multiplexed quantitation of PTEN and p110α concentrations, without the limitations of immunohistochemistry. Our iMALDI assay only requires a low-cost benchtop MALDI-TOF mass spectrometer, which simplifies clinical translation. We validated our assay's precision and accuracy, with simultaneous enrichment of both target proteins not significantly affecting the precision and accuracy of the quantitation when compared to the PTEN- and p110α-singleplex iMALDI assays (<15% difference). The multiplexed assay's linear range is from 0.6-20 fmol with accuracies of 90-112% for both target proteins, and the assay is free of matrix-related interferences. The inter-day reproducibility over 5-days was high, with an overall CV of 9%. PTEN and p110α protein concentrations can be quantified down to 1.4 fmol and 0.6 fmol per 10 µg of total tumor protein, respectively, in various tumor tissue samples, including fresh-frozen breast tumors and colorectal cancer liver metastases, and patient-derived xenograft (PDX) tumors.

Precise Quantitation of PTEN by Immuno-MRM: A Tool To Resolve the Breast Cancer Biomarker Controversy.

The tumor suppressor PTEN is the main negative regulator of PI3K/AKT/mTOR signaling and is commonly found downregulated in breast cancer (BC). Conflicting data from conventional immunoassays such as immunohistochemistry (IHC) has sparked controversy about PTEN's role as a prognostic and predictive biomarker in BC, which can be largely attributed to the lack of specificity, sensitivity, and interlaboratory standardization. Here, we present a fully standardized, highly sensitive, robust microflow immuno-MRM (iMRM) assay that enables precise quantitation of PTEN concentrations in cells and fresh frozen (FF) and formalin-fixed paraffin-embedded (FFPE) tissues, down to 0.1 fmol/10 µg of extracted protein, with high interday and intraday precision (CV 6.3%). PTEN protein levels in BC PDX samples that were determined by iMRM correlate well with semiquantitative IHC and WB data. iMRM, however, allowed the precise quantitation of PTEN-even in samples that were deemed to be PTEN negative by IHC or western blot (WB)-while requiring substantially less tumor tissue than WB. This is particularly relevant because the extent of PTEN downregulation in tumors has been shown to correlate with severity. Our standardized and robust workflow includes an 11 min microflow LC-MRM analysis on a triple-quadrupole MS and thus provides a much needed tool for the study of PTEN as a potential biomarker for BC.

The role of iron in the pathogenesis of COVID-19 and possible treatment with lactoferrin and other iron chelators.

Iron overload is increasingly implicated as a contributor to the pathogenesis of COVID-19. Indeed, several of the manifestations of COVID-19, such as inflammation, hypercoagulation, hyperferritinemia, and immune dysfunction are also reminiscent of iron overload. Although iron is essential for all living cells, free unbound iron, resulting from iron dysregulation and overload, is very reactive and potentially toxic due to its role in the generation of reactive oxygen species (ROS). ROS react with and damage cellular lipids, nucleic acids, and proteins, with consequent activation of either acute or chronic inflammatory processes implicated in multiple clinical conditions. Moreover, iron-catalyzed lipid damage exerts a direct causative effect on the newly discovered nonapoptotic cell death known as ferroptosis. Unlike apoptosis, ferroptosis is immunogenic and not only leads to amplified cell death but also promotes a series of reactions associated with inflammation. Iron chelators are generally safe and are proven to protect patients in clinical conditions characterized by iron overload. There is also an abundance of evidence that iron chelators possess antiviral activities. Furthermore, the naturally occurring iron chelator lactoferrin (Lf) exerts immunomodulatory as well as anti-inflammatory effects and can bind to several receptors used by coronaviruses thereby blocking their entry into host cells. Iron chelators may consequently be of high therapeutic value during the present COVID-19 pandemic.

Direct and Precise Measurement of Bevacizumab Levels in Human Plasma Based on Controlled Methionine Oxidation and Multiple Reaction Monitoring.

Bevacizumab is a monoclonal antibody which targets vascular endothelial growth factor A (VEGF-A) and is used to treat various cancers and recently COVID-19. The dosage recommendations for bevacizumab are determined on the basis of body weight, and the drug is administered after defined time intervals, when it is presumed to still be above its minimum effective serum concentration. Interindividual and disease-stage-related variations in bevacizumab catabolism, however, can affect the proper dosing of patients, resulting in plasma concentrations which may not be within the optimal therapeutic window for the drug. Therapeutic drug monitoring (TDM) enables the assessment of patients' serum concentrations and allows personalized dosing which has the potential to improve efficacy and reduce side effects. While TMD is often performed using ligand-based assays, mass spectrometry (MS)-based TDM offers improved specificity. Here, we present a robust multiple reaction monitoring (MRM)-MS-based TDM method for the precise quantification of bevacizumab plasma concentrations, based on the controlled oxidation of the methionine-containing peptide, STAYLQMNSLR. The assay shows good linearity (r 2 = 0.9951), robustness, and precision (CVs < 20%) for the quantification of bevacizumab, with a lower limit of quantification (S/N > 10) of 1.8 µg/mL of plasma, without the need for enrichment and requiring less than 1 µL of plasma and less than 6 h from sampling to result.

Using Two Peptide Isotopologues as Internal Standards for the Streamlined Quantification of Low-Abundance Proteins by Immuno-MRM and Immuno-MALDI.

Mass spectrometry (MS), particularly targeted proteomics, is increasingly being used for quantifying specific proteins and peptides in clinical specimens. The coupling of immuno-enrichment of proteotypic peptides with MS [e.g., immuno-multiple reaction monitoring (MRM) and immuno-matrix-assisted laser desorption ionization (MALDI)] enables the development of highly sensitive and specific assays for low-abundance signaling proteins. By incorporating stable isotope-labeled standards, these workflows allow the determination of endogenous protein concentrations. This is typically achieved through external calibration, often using surrogate matrices, which has inherent limitations for the analysis of clinical specimens as there are often substantial variations in the sample matrix, and sample amounts are typically limited. We have previously introduced the use of two peptide isotopologues for generating external calibration curves in plasma. Here, we present a two-point internal calibration (2-PIC) strategy using two isotopologues for immuno-MS assays and demonstrate its flexibility and robustness. Quantification of the tumor suppressor PTEN in Colo-205 cells by immuno-MRM and immuno-MALDI using 2-PIC and external calibration yielded very similar results (relative standard deviation between 2-PIC and external calibration: 4.9% for immuno-MRM; 1.1% for immuno-MALDI), without the need for a surrogate matrix or additional patient material for calibration, while concurrently reducing the instrument time and cost. Although our PTEN immuno-MRM and immuno-MALDI assays can be considered to be orthogonal as they utilized entirely different sample preparation and MS analysis workflows, targeted different PTEN peptides, and were performed in different laboratories, the endogenous Colo-205 PTEN levels determined with 2-PIC showed a good correlation (r2 = 0.9966) and good agreement (0.48 ± 0.01 and 0.29 ± 0.02 fmol/µg of total protein) between immuno-MRM and immuno-MALDI.

Effect of Peribulbar Anesthesia with and Without Adrenaline on Retinal Thickness in Patients Undergoing Elective Cataract Surgery.

BACKGROUND: The toxic effect of local anesthesia on the retina has been previously investigated in animal studies but not in humans. OBJECTIVES: The objective of this study was to clarify the effect of local anesthesia with lidocaine versus local anesthesia with lidocaine with extra administration of adrenaline on the retinal layer thickness measured by optical coherence tomography (OCT) in patients indicated for elective cataract surgery. METHODS: This is a randomized controlled trial conducted on 60 patients indicated for elective cataract surgery under local anesthesia with lidocaine. Thirty participants received local anesthesia with lidocaine 2% with extra administration of adrenaline (adrenaline group), and 30 participants received local anesthesia with lidocaine 2% only (control group). The retinal thickness was measured for all participants preoperatively and one week postoperatively using OCT. RESULTS: The OCT findings showed statistically significant decreases postoperatively in superior (P value = 0.028), inferior (P value = 0.017), and average (P value = 0.021) retinal thickness in the adrenaline group. Moreover, there were statistically significant decreases postoperatively in superior (P value = 0.032), inferior (P value = 0.046), and average (P value = 0.028) retinal thickness in the control group. Comparing the adrenaline and control groups for the OCT findings, there was no statistically significant difference between the groups regarding the decreases in superior (P value = 0.325), inferior (P value = 0.642), and average (P value = 0.291) retinal thickness. CONCLUSIONS: Local anesthesia with lidocaine significantly decreased the retinal thickness. The extra administration of adrenaline to lidocaine did not affect the post-anesthetic changes in the retinal thickness.

Systematic Optimization of the iMALDI Workflow for the Robust and Straightforward Quantification of Signaling Proteins in Cancer Cells.

PURPOSE: Immuno-MALDI (iMALDI) combines immuno-enrichment of biomarkers with MALDI-MS for fast, precise, and specific quantitation, making it a valuable tool for developing clinical assays. iMALDI assays are optimized for the PI3-kinase signaling pathway members phosphatase and tensin homolog (PTEN) and PI3-kinase catalytic subunit alpha (p110α), with regard to sensitivity, robustness, and throughput. A standardized template for developing future iMALDI assays, including automation protocols to streamline assay development and translation, is provided. EXPERIMENTAL DESIGN: Conditions for tryptic digestion and immuno-enrichment (beads, bead:antibody ratios, incubation times, direct vs. indirect immuno-enrichment) are rigorously tested. Different strategies for calibration and data readout are compared. RESULTS: Digestion using 1:2 protein:trypsin (wt:wt) for 1 h yielded high and consistent peptide recoveries. Direct immuno-enrichment (antibody-bead coupling prior to antigen-enrichment) yielded 30% higher peptide recovery with a 1 h shorter incubation time than indirect enrichment. Immuno-enrichment incubation overnight yielded 1.5-fold higher sensitivities than 1 h incubation. Quantitation of the endogenous target proteins is not affected by the complexity of the calibration matrix, further simplifying the workflow. CONCLUSIONS AND CLINICAL RELEVANCE: This optimized and automated workflow will facilitate the clinical translation of high-throughput sensitive iMALDI assays for quantifying cell-signaling proteins in individual tumor samples, thereby improving patient stratification for targeted treatment.

Association of hypertension, diabetes, stroke, cancer, kidney disease, and high-cholesterol with COVID-19 disease severity and fatality: A systematic review.

BACKGROUND AND AIMS: To undertake a review and critical appraisal of published/preprint reports that offer methods of determining the effects of hypertension, diabetes, stroke, cancer, kidney issues, and high-cholesterol on COVID-19 disease severity. METHODS: A search was conducted by two authors independently on the freely available COVID-19 Open Research Dataset (CORD-19). We developed an automated search engine to screen a total of 59,000 articles in a few seconds. Filtering of the articles was then undertaken using keywords and questions, e.g. "Effects of diabetes on COVID/normal coronavirus/SARS-CoV-2/nCoV/COVID-19 disease severity, mortality?". The search terms were repeated for all the comorbidities considered in this paper. Additional articles were retrieved by searching via Google Scholar and PubMed. FINDINGS: A total of 54 articles were considered for a full review. It was observed that diabetes, hypertension, and cholesterol levels possess an apparent relation to COVID-19 severity. Other comorbidities, such as cancer, kidney disease, and stroke, must be further evaluated to determine a strong relationship to the virus. CONCLUSION: Reports associating cancer, kidney disease, and stroke with COVID-19 should be carefully interpreted, not only because of the size of the samples, but also because patients could be old, have a history of smoking, or have any other clinical condition suggesting that these factors might be associated with the poor COVID-19 outcomes rather than the comorbidity itself. Further research regarding this relationship and its clinical management is warranted.

Chemical constituents of the aerial parts of Salvia judaica Boiss. from Jordan.

Investigation of the chemical constituents of Salvia judaica growing wild in Jordan led to the isolation and identification of 15 known compounds. These included: luteolin-3'-methyl ether (1), indole-3-carboxyaldehyde (2), p-hydroxybenzaldehyde (3), tricin (4), apigenin (5), methyl isoferuloyl-7-(3,4-dihydroxyphenyl) lactate (6), methyl rosmarinate (7), rosmarinic acid (8), salvigenin (9), ß-sitosterol (10), 3ß, 28-dihydroxyurs-12-ene (11), cirsilineol (12), 2,3-dihydroxyurs-12-en-28-oic acid (13), ß-sitosteryl glucoside (14), and tormentic acid (15). Compounds 6 and 7 exhibited strong radical scavenging and chelating activities as compared to α-tocopherol and ascorbic acid, compound 7 showed a 2-fold greater antioxidant activity as compared to compound 6. Furthermore, low doses of compounds 6 and 7 were able to inhibit the growth of leukemic (HL-60, Jurkat, K562 and CCRF-SB) and solid tumor cells (MCF-7, MDA-MB-231 and Caco-2). Compound 7 showed a ca. 3-4-fold stronger cytotoxicity against the tested cells as compared to compound 6.

Targeted and Untargeted Proteomics Approaches in Biomarker Development.

An enormous amount of research effort has been devoted to biomarker discovery and validation. With the completion of the human genome, proteomics is now playing an increasing role in this search for new and better biomarkers. Here, what leads to successful biomarker development is reviewed and how these features may be applied in the context of proteomic biomarker research is considered. The "fit-for-purpose" approach to biomarker development suggests that untargeted proteomic approaches may be better suited for early stages of biomarker discovery, while targeted approaches are preferred for validation and implementation. A systematic screening of published biomarker articles using MS-based proteomics reveals that while both targeted and untargeted technologies are used in proteomic biomarker development, most researchers do not combine these approaches. i) The reasons for this discrepancy, (ii) how proteomic technologies can overcome technical challenges that seem to limit their translation into the clinic, and (iii) how MS can improve, complement, or replace existing clinically important assays in the future are discussed.