Targeting metabolic adaptive responses induced by glucose starvation inhibits cell proliferation and enhances cell death in osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines

Osimertinib, a tyrosine kinase inhibitor targeting mutant EGFR, has received approval for initial treatment in patients with Non-Small Cell Lung Cancer (NSCLC). While effective in both first- and second-line treatments, patients eventually develop acquired resistance. Metabolic reprogramming represents a strategy through which cancer cells may resist and adapt to the selective pressure exerted by the drug. In the current study, we investigated the metabolic adaptations associated with osimertinib-resistance in NSCLC cells under low glucose culture conditions. We demonstrated that, unlike osimertinib-sensitive cells, osimertinib-resistant cells were able to survive under low glucose conditions by increasing the rate of glucose and glutamine uptake and by shifting towards mitochondrial metabolism. Inhibiting glucose/pyruvate contribution to mitochondrial respiration, glutamine deamination to glutamate, and oxidative phosphorylation decreased the proliferation and survival abilities of osimertinib-resistant cells to glucose starvation. Our findings underscore the remarkable adaptability of osimertinib-resistant NSCLC cells in a low glucose environment and highlight the pivotal role of mitochondrial metabolism in mediating this adaptation. Targeting the metabolic adaptive responses triggered by glucose shortage emerges as a promising strategy, effectively inhibiting cell proliferation and promoting cell death in osimertinib-resistant cells.

Targeting glucosylceramide synthase induces antiproliferative and proapoptotic effects in osimertinib-resistant NSCLC cell models

The EGFR tyrosine kinase inhibitor osimertinib has been approved for the first-line treatment of EGFR-mutated Non-Small Cell Lung Cancer (NSCLC) patients. Despite its efficacy, patients develop resistance. Mechanisms of resistance are heterogeneous and not fully understood, and their characterization is essential to find new strategies to overcome resistance. Ceramides are well-known regulators of apoptosis and are converted into glucosylceramides (GlcCer) by glucosylceramide synthase (GCS). A higher content of GlcCers was observed in lung pleural effusions from NSCLC patients and their role in osimertinib-resistance has not been documented. The aim of this study was to determine the therapeutic potential of inhibiting GCS in NSCLC EGFR-mutant models resistant to osimertinib in vitro and in vivo. Lipidomic analysis showed a significant increase in the intracellular levels of glycosylceramides, including GlcCers in osimertinib resistant clones compared to sensitive cells. In resistant cells, the GCS inhibitor PDMP caused cell cycle arrest, inhibition of 2D and 3D cell proliferation, colony formation and migration capability, and apoptosis induction. The intratumoral injection of PDMP completely suppressed the growth of OR xenograft models. This study demonstrated that dysregulation of ceramide metabolism is involved in osimertinib-resistance and targeting GCS may be a promising therapeutic strategy for patients progressed to osimertinib.

Molecular Determinants of EphA2 and EphB2 Antagonism Enable the Design of Ligands with Improved Selectivity

With the aim of identifying novel antagonists selective for the EphA receptor family, a combined experimental and computational approach was taken to investigate the molecular basis of the recognition between a prototypical Eph-ephrin antagonist (UniPR1447) and two representative receptors of the EphA and EphB subfamilies, namely, EphA2 and EphB2 receptors. The conformational free-energy surface (FES) of the binding state of UniPR1447 within the ligand binding domain of EphA2 and EphB2, reconstructed from molecular dynamics (MD) simulations performed on the microsecond time scale, was exploited to drive the design and synthesis of a novel antagonist selective for EphA2 over the EphB2 receptor. The availability of compounds with this pharmacological profile will help discriminate the importance of these two receptors in the insurgence and progression of cancer.

Unbinding Kinetics of Muscarinic M3 Receptor Antagonists Explained by Metadynamics Simulations

The residence time (RT), the time for which a drug remains bound to its biological target, is a critical parameter for drug design. The prediction of this key kinetic property has been proven to be challenging and computationally demanding in the framework of atomistic simulations. In the present work, we setup and applied two distinct metadynamics protocols to estimate the RTs of muscarinic M3 receptor antagonists. In the first method, derived from the conformational flooding approach, the kinetics of unbinding is retrieved from a physics-based parameter known as the acceleration factor α (i.e., the running average over time of the potential deposited in the bound state). Such an approach is expected to recover the absolute RT value for a compound of interest. In the second method, known as the t_META-D approach, a qualitative estimation of the RT is given by the time of simulation required to drive the ligand from the binding site to the solvent bulk. This approach has been developed to reproduce the change of experimental RTs for compounds targeting the same target. Our analysis shows that both computational protocols are able to rank compounds in agreement with their experimental RTs. Quantitative structure-kinetics relationship (SKR) models can be identified and employed to predict the impact of a chemical modification on the experimental RT once a calibration study has been performed.

Pharmacological characterization of second generation FXR agonists as effective EphA2 antagonists: A successful application of target hopping approach

It is well demonstrated the key role of Eph-ephrin system, specifically of EphA2 receptor, in supporting tumor growth, invasion, metastasis and neovascularization. We previously identified FXR agonists as eligible antagonists of Eph-ephrin system. Herein we characterize new commercially available FXR (Farnesoid X Receptor) agonists as potential Eph ligands including Cilofexor, Nidufexor, Tropifexor, Turofexorate isopropyl and Vonafexor. Our exploration based on molecular modelling investigations and binding assays shows that Cilofexor binds specifically and reversibly to EphA2 receptor with a Ki value in the low micromolar range. Furthermore, Cilofexor interferes with the phosphorylation of EphA2 and the cell retraction and rounding in PC3 prostate cancer cells, both events depending on EphA2 activation. In conclusion, we can confirm that target hopping can be a successful approach to discover new moiety of protein-protein inhibitors.

Mechanistic Modeling of Lys745 Sulfonylation in EGFR C797S Reveals Chemical Determinants for Inhibitor Activity and Discriminates Reversible from Irreversible Agents

Targeted covalent inhibitors hold promise for drug discovery, particularly for kinases. Targeting the catalytic lysine of epidermal growth factor receptor (EGFR) has attracted attention as a new strategy to overcome resistance due to the emergence of C797S mutation. Sulfonyl fluoride derivatives able to inhibit EGFR^{L858R/T790M/C797S} by sulfonylation of Lys745 have been reported. However, atomistic details of this process are still poorly understood. Here, we describe the mechanism of inhibition of an innovative class of compounds that covalently engage the catalytic lysine of EGFR, through a sulfur(VI) fluoride exchange (SuFEx) process, with the help of hybrid quantum mechanics/molecular mechanics (QM/MM) and path collective variables (PCVs) approaches. Our simulations identify the chemical determinants accounting for the irreversible activity of agents targeting Lys745 and provide hints for the further optimization of sulfonyl fluoride agents.

Development of potent and selective FAAH inhibitors with improved drug-like properties as potential tools to treat neuroinflammatory conditions

The neuroprotective performance against neuroinflammation of the endocannabinoid system (ECS) can be remarkably improved by indirect stimulation mediated by the pharmacological inhibition of the key ECS catabolic enzyme fatty acid amide hydrolase (FAAH). Based on our previous works and aiming to discover new selective FAAH inhibitors , we herein reported a new series of carbamate-based FAAH inhibitors (4a-t) which showed improved drug disposition properties compared to the previously reported analogues 2a-b. The introduction of ionizable functions allowed us to obtain new FAAH inhibitors of nanomolar potency characterized by good water solubility and chemical stability at physiological pH. Interesting structure-activity relationships (SARs), deeply analyzed by molecular docking and molecular dynamic (MD) simulations, were obtained. All the newly developed inhibitors showed an excellent selectivity profile evaluated against monoacylglycerol lipase and cannabinoid receptors. The reversible mechanism of action was determined by a rapid dilution assay. Absence of toxicity was confirmed in mouse fibroblasts NIH3T3 (for compounds 4e, 4g, 4n-o, and 4s) and in human astrocytes cell line 1321N1 (for compounds 4e, 4n, and 4s). The absence of undesired cardiac effects was also confirmed for compound 4n. Selected analogues (compounds 4e, 4g, 4n, and 4s) were able to reduce oxidative stress in 1321N1 astrocytes and exhibited notable neuroprotective effects when tested in an ex vivo model of neuroinflammation.

Mechanistic Modeling of Monoglyceride Lipase Covalent Modification Elucidates the Role of Leaving Group Expulsion and Discriminates Inhibitors with High and Low Potency

Inhibition of monoglyceride lipase (MGL), also known as monoacylglycerol lipase (MAGL), has emerged as a promising approach for treating neurological diseases. To gain useful insights in the design of agents with balanced potency and reactivity, we investigated the mechanism of MGL carbamoylation by the reference triazole urea SAR629 (IC₅₀ = 0.2 nM) and two recently described inhibitors featuring a pyrazole (IC₅₀ = 1800 nM) or a 4-cyanopyrazole (IC₅₀ = 8 nM) leaving group (LG), using a hybrid quantum mechanics/molecular mechanics (QM/MM) approach. Opposite to what was found for substrate 2-arachidonoyl-sn-glycerol (2-AG), covalent modification of MGL by azole ureas is controlled by LG expulsion. Simulations indicated that changes in the electronic structure of the LG greatly affect reaction energetics with triazole and 4-cyanopyrazole inhibitors following a more accessible carbamoylation path compared to the unsubstituted pyrazole derivative. The computational protocol provided reaction barriers able to discriminate between MGL inhibitors with different potencies. These results highlight how QM/MM simulations can contribute to elucidating structure–activity relationships and provide insights for the design of covalent inhibitors.

Auditory brainstem response in postmenopausal women treated with hormone replacement therapy: a pilot study

OBJECTIVE

To research the nongenital audiological target for gonadal steroids in postmenopausal women who are treated with hormone replacement therapy.

DESIGN

Fifty postmenopausal volunteers were treated with hormone replacement therapy. Women with an intact uterus had sequential weekly transdermal estradiol plus nomegestrole acetate 5 mg orally for 12 days per month or a continuous daily oral dose of conjugated estrogen 0.625 mg and medroxyprogesterone acetate 5 mg tablet. Eighteen surgically postmenopausal women received a weekly transdermal estradiol system. Twenty-five postmenopausal volunteers-5 with a natural menopause and 10 with a surgical menopause-and 20 premenopausal normally cycling women were used as a control group. Each woman performed auditory brainstem response by auditory-evoked potentials for waves I, III, and V and for interpeak I-III, I-V, and III-V intervals.

RESULTS

Women who were treated with hormone replacement therapy showed wave latencies and interpeak latencies shorter than those for postmenopausal women in the control group (p < or = 0.05), overlapping those of the premenopausal women (p > 0.05). Women who were treated with estrogen replacement therapy showed shorter time latencies than those treated with combined hormone replacement therapy (p < or = 0.05).

CONCLUSIONS

Our data suggest that fluctuating hormone levels cause changes in auditory brain-stem response waves, even if the exact mechanism of activity of the gonadal steroids is not clear. However, we believe that estrogen may influence the neuronal plasticity, the metabolic levels of neurotransmitters, and thus the neuronal conduction time into the audiological system.

Endocrine and metabolic effects of octreotide, a somatostatin analogue, in lean PCOS patients with either hyperinsulinaemia or lean normoinsulinaemia

The effects on insulin secretion and on the glycaemic and androgen status before and after short-term treatment with octreotide were evaluated in 16 normal weight patients with polycystic ovarian syndrome (PCOS). Hyperinsulinaemia was determined by measuring the insulin response after oral glucose tolerance test (OGTT). Seven patients (group A) were classified as normoinsulinaemic, while nine patients (group B) were considered hyperinsulinaemic according to insulin response after OGTT. Octreotide treatment did not modify either glycaemic or insulinaemic response after OGTT, or androgen profile, in normoinsulinaemic patients. On the contrary, a significant decrease in the basal concentrations of luteinizing hormone (LH), testosterone and androstenedione, and a significant increase in serum concentrations of sex hormone-binding globulin (SHBG) were observed in the hyperinsulinaemic group of patients, in which we observed also a significant decrease of insulinaemic response and a decompensation of the glycaemic profile after OGTT. Our study is the first report showing that: (i) octreotide does not appear to significantly influence pituitary release of gonadotrophins in this group of PCOS patients; (ii) octreotide is able to reduce insulin release, LH and androgen concentrations in lean PCOS patients with hyperinsulinaemia. Due to the presence of a decompensation of glucose homeostasis during treatment, octreotide does not seem advisable for long-term therapy of hyperandrogenism in lean PCOS patients with hyperinsulinaemia.

Evaluation of a new enzyme immunoassay for detecting Helicobacter pylori in feces: a prospective pilot study

OBJECTIVE

There is an increasing interest in noninvasive tests for detecting Helicobacter pylori (H. pylori) infection. Unlike serological and urea breath tests, the possibility of searching for H. pylori in feces has been scarcely investigated. The aim of this prospective pilot study was to evaluate the usefulness of a new enzyme immunoassay for detecting H. pylori antigens in feces, as a predictor of H. pylori status in the pre- and posttreatment settings.

METHODS

One hundred and fifty-four symptomatic, anti-H. pylori untreated patients (Group A) and 116 anti-H. pylori treated patients (Group B) underwent gastroscopy with biopsies of the antrum and corpus for histology (H) and rapid urease test (RUT). In the anti-H. pylori treated group, a 13C-urea breath test (UBT) was also performed. In Group A, H. pylori status was defined as positive or negative when both H and RUT gave concordant positive or negative results. In Group B, the patients were considered eradicated if all three tests were negative. A stool specimen was collected from all patients the day after gastroscopy, and tested by using an enzyme immunoassay commercial kit for detecting H. pylori antigens in feces (HpSAT).

RESULTS

Eighty-five patients in Group A (55%) and 44 in Group B (38%) were H. pylori infected. On the whole, HpSAT showed a sensitivity of 94% and specificity of 86%. In Group A and Group B, sensitivity and specificity were 94% versus 93%, and 90% versus 82%, respectively (p < 0.05).

CONCLUSIONS

HpSAT seems to be a reliable method for predicting H. pylori status in anti-H. pylori untreated patients. Conversely, the test appears less suitable to evaluate the outcome of the eradicating treatment. Consequently, it is likely to be accepted for the primary diagnosis of H. pylori status, particularly in dyspeptic young patients.

Evaluation of a new ultrashort triple therapy for Helicobacter pylori disease

BACKGROUND

1-week proton pump inhibitor-based triple therapies are considered the most effective and convenient drug combinations for curing Helicobacter pylori infection. Short therapies, lasting less than 1 week have been investigated rarely.

AIM

To assess the efficacy and tolerability of a 3-day lansoprazole triple therapy after 1 day of lansoprazole pre-treatment.

METHODS

Seventy H. pylori-positive (rapid urease test and histology) patients received LAzT3 regimen (lanzoprazole 30 mg b.d. and azithromycin 500 mg o.m. for 3 days; tinidazole 2000 mg o.m. on day 1 and 1000 mg o.m. on days 2-3) after 1 day of lansoprazole pretreatment. Patients with active ulcer received lansoprazole 30 mg o.m. for an additional 4 weeks. Follow-up gastroscopy was carried out 4-6 weeks after completion of therapy. Eradication was defined as negative histology and rapid urease test.

RESULTS

Four patients failed to attend the follow-up endoscopy. One patient complained of minor side-effects. H. pylori was eradicated in 57 of 66 patients suitable for evaluation, with a per-protocol cure rate of 86.3% (95%CI: 76-94%), and an intention-to-treat cure rate of 81.4% (95%CI: 70-90%).

CONCLUSIONS

This new ultrashort triple therapy including lansoprazole, azithromycin and tinidazole seems to be effective in eradicating H. pylori. It is safe and well-tolerated, and may be taken into consideration as a valid alternative to the better known and widely used 1-week proton pump inhibitor-based triple therapies.

Usefulness of brushing urease test for diagnosis of Helicobacter pylori infection

BACKGROUND AND AIMS

Gastric brushing cytology is an accurate technique for rapidly detecting Helicobacter pylori infection, but it is not routinely employed since the presence of personnel experienced in this field, is necessary in the endoscopy suite. To evaluate the diagnostic usefulness of rapid urease test carried out on cytological brushing.

PATIENTS

A total of 143 consecutive patients with suspected Helicobacter pylori infection, referred for elective gastroscopy.

METHODS

For each patient, 2 brushings were carried out and 4 biopsies were taken from antral mucosa during gastroscopy. The former brushing was smeared on a slide, and stained by a rapid staining set for blood smears. The latter was used for rapid urease test, by shaking the brush into the urea broth. Two biopsies were used for rapid urease test and two for histologic examination. Histology was considered as the gold standard.

RESULTS

Of 143 patients, 73 were diagnosed as Helicobacter pylori infected using histology. Six brushing slides were inadequate due to insufficient cytology material. Biopsy-rapid urease test and brushing-rapid urease test had similar sensitivity (87.3% vs 83.5%), specificity (98.4% vs 96.8%) and overall accuracy (92.3% vs 89.5%). In 62 Helicobacter pylori infected patients, both rapid urease test techniques were positive. Brushing-rapid urease test became positive in a significantly shorter time than biopsy-rapid urease test (22 +/- 54 minutes vs 39 +/- 63 minutes; p < 0.01).

CONCLUSIONS

Brushing-rapid urease test is as accurate as biopsy-rapid urease test in detecting Helicobacter pylori infection, but it is significantly faster. Special care should be taken to carry out brushing adequately, to minimize the occurrence of false negatives.

Pavel's "dynamic screening" for diabetes type 2: 14 years results in a district of northern Italy

The AA. report the results of 14 years' screening for diabetes type 2 in their Health District (Emilia Romagna, North Italy), according to Pavel's method, for early diagnosis of clinical diabetes and impaired glucose tolerance (IGT). The AA. found in a first screening 1.03% of clinical diabetes and 2.65% of IGT cases in the population examined (200,000 subjects). Statistically significant correlations existed in relation to the various risk factors (hereditary factors, obesity, fetal macrosomia, job). The follow-up after 6 years for IGT subjects showed a 25.5% return to normal oral glucose tolerance test (OGTT) values, 21.7% improvement, 19% unchanged, 33.8% impairment. There was a correlation between these results and life-style (diet, physical exercise, weight loss). Fourteen years after these screening, a 2.7% negative incidence was observed for diabetes type 2 in this Health District.