Receptor Kinase Research Articles

Novel therapeutic strategies for rare mutations in non-small cell lung cancer

Lung cancer is still the leading cause of cancer-related mortality. Over the past two decades, the management of non-small cell lung cancer (NSCLC) has undergone a significant revolution. Since the first identification of activating mutations in the epidermal growth factor receptor (EGFR) gene in 2004, several genetic aberrations, such as anaplastic lymphoma kinase rearrangements (ALK), neurotrophic tropomyosin receptor kinase (NTRK) and hepatocyte growth factor receptor (MET), have been found. With the development of gene sequencing technology, the development of targeted drugs for rare mutations, such as multikinase inhibitors, has provided new strategies for treating lung cancer patients with rare mutations. Patients who harbor this type of oncologic driver might acquire a greater survival benefit from the use of targeted therapy than from the use of chemotherapy and immunotherapy. To date, more new agents and regimens can achieve satisfactory results in patients with NSCLC. In this review, we focus on recent advances and highlight the new approval of molecular targeted therapy for NSCLC patients with rare oncologic drivers.

Identification of potent pan-ephrin receptor kinase inhibitors using DNA-encoded chemistry technology

EPH receptors (EPHs), the largest family of tyrosine kinases, phosphorylate downstream substrates upon binding of ephrin cell surface-associated ligands. In a large cohort of endometriotic lesions from individuals with endometriosis, we found that EPHA2 and EPHA4 expressions are increased in endometriotic lesions relative to normal eutopic endometrium. Because signaling through EPHs is associated with increased cell migration and invasion, we hypothesized that chemical inhibition of EPHA2/4 could have therapeutic value. We screened DNA-encoded chemical libraries (DECL) to rapidly identify EPHA2/4 kinase inhibitors. Hit compound, CDD-2693, exhibited picomolar/nanomolar kinase activity against EPHA2 (Ki: 4.0 nM) and EPHA4 (Ki: 0.81 nM). Kinome profiling revealed that CDD-2693 bound to most EPH family and SRC family kinases. Using NanoBRET target engagement assays, CDD-2693 had nanomolar activity versus EPHA2 (IC50: 461 nM) and EPHA4 (IC50: 40 nM) but was a micromolar inhibitor of SRC, YES, and FGR. Chemical optimization produced CDD-3167, having picomolar biochemical activity toward EPHA2 (Ki: 0.13 nM) and EPHA4 (Ki: 0.38 nM) with excellent cell-based potency EPHA2 (IC50: 8.0 nM) and EPHA4 (IC50: 2.3 nM). Moreover, CDD-3167 maintained superior off-target cellular selectivity. In 12Z endometriotic epithelial cells, CDD-2693 and CDD-3167 significantly decreased EFNA5 (ligand) induced phosphorylation of EPHA2/4, decreased 12Z cell viability, and decreased IL-1β-mediated expression of prostaglandin synthase 2 (PTGS2). CDD-2693 and CDD-3167 decreased expansion of primary endometrial epithelial organoids from patients with endometriosis and decreased Ewing's sarcoma viability. Thus, using DECL, we identified potent pan-EPH inhibitors that show specificity and activity in cellular models of endometriosis and cancer.

Abstract PO3-18-04: MBRC-101: a novel antibody-drug conjugate (ADC) targeting the membrane-associated tyrosine kinase receptor EphA5 in breast cancer

Abstract Objectives: ADCs have emerged as a major advance in contemporary medical oncology. The receptor tyrosine kinase (RTK) EphA5 possesses the classical receptor kinase topology with an extracellular-binding domain, a single-pass transmembrane domain, and a cytoplasmic kinase domain. We have previously shown that EphA5 is highly expressed in non-small cell lung cancer and contributes to DNA-damage repair and radiation therapy resistance. Others have reported EphA5 expression in gastric, ovarian, and pancreatic cancers. Here, we investigated the expression of EphA5 in breast cancer (BC) and assessed EphA5 as a potential cancer-specific target using a novel ADC designated MBRC-101. Methods: MBRC-101 is composed of a humanized anti-EphA5 IgG1 kappa monoclonal antibody conjugated to the small molecule microtubule-disrupting agent monomethyl auristatin E (MMAE) via a protease cleavable valine-citrulline (vc) ThioBridge linker (ThioBridge™-Glu-[Val-Cit-PAB-MMAE] PEG [24u]). MBRC-101 averages a drug-to-antibody ratio (DAR)=4. The specificity profile of the anti-EphA5 monoclonal antibody was characterized using a Membrane Proteome Array (MPA). Receptor-mediated antibody internalization was determined by real-time live-cell analysis; cell killing assays used both live-cell analysis of cell confluence and the CellTiter-Glo® luminescent cell viability assay. Expression of EphA5 in archival human breast tumor tissue sections was evaluated by immunohistochemistry (IHC) using a commercial polyclonal antibody against human EphA5. In vivo efficacy studies used patient-derived xenograft (PDX) models of BC. Results: IHC demonstrated robust and selective EphA5 expression in 87% (20 of 23) of triple negative breast cancer (TNBC) and 88% (23 of 26) of hormone receptor-positive (HR+) patient tumors tested. EphA5 expression was not detected in adjacent, non-malignant breast tissue. Antibody-specificity profile testing showed that the anti-EphA5 antibody bound exclusively to EphA5 and did not cross-react with other members of the Eph receptor/ephrin ligand family. Binding of the anti-EphA5 antibody to EphA5 on the cell surface triggered rapid internalization and processing of the EphA5/antibody complex through the endosomal-lysosomal system. Consistently, MBRC-101 was cytotoxic to EphA5-expressing cells and its activity was concentration-dependent and commensurate to the levels of EphA5 on the cell surface. In PDX murine models of TNBC, once weekly administrations of intravenous (IV) MBRC-101 showed dose-dependent, robust, and reproducible anti-tumor activity in vivo. Partial tumor responses were observed at doses of 2.5 mg/Kg IV and complete and nearly complete tumor responses starting at 5 mg/Kg IV. Doses up to 10 mg/Kg IV were well-tolerated in tumor-bearing mice with no observable weight loss. Pre-clinical safety confirmed MBRC-101 is also well tolerated in rats and in cynomolgus monkeys. Conclusions: These results support EphA5 as a new and promising membrane-associated molecular target for the design and development of ADC-based therapies against hormone-positive breast cancer and TNBC and support the conduct of a Phase 1/1b study of MBRC-101 in patients with breast cancer. Citation Format: Fernanda Staquicini, Fenny Tang, Vanessa de Oliveira, Daniela Staquicini, Yongjian Wu, Kirstin Barnhart, J Kellogg Parsons, Wadih Arap, Isan Chen, Renata Pasqualini. MBRC-101: a novel antibody-drug conjugate (ADC) targeting the membrane-associated tyrosine kinase receptor EphA5 in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-18-04.

The Arabidopsis SGN3/GSO1 receptor kinase integrates soil nitrogen status into shoot development.

The Casparian strip is a barrier in the endodermal cell walls of plants that allows the selective uptake of nutrients and water. In the model plant Arabidopsis thaliana, its development and establishment are under the control of a receptor-ligand mechanism termed the Schengen pathway. This pathway facilitates barrier formation and activates downstream compensatory responses in case of dysfunction. However, due to a very tight functional association with the Casparian strip, other potential signaling functions of the Schengen pathway remain obscure. In this work, we created a MYB36-dependent synthetic positive feedback loop that drives Casparian strip formation independently of Schengen-induced signaling. We evaluated this by subjecting plants in which the Schengen pathway has been uncoupled from barrier formation, as well as a number of established barrier-mutant plants, to agar-based and soil conditions that mimic agricultural settings. Under the latter conditions, the Schengen pathway is necessary for the establishment of nitrogen-deficiency responses in shoots. These data highlight Schengen signaling as an essential hub for the adaptive integration of signaling from the rhizosphere to aboveground tissues.

Abstract PO4-23-09: Dual inhibition of FGFR4 and HER2/EGFR with Lapatinib improves targeting of Erk and Akt signaling in HER2+ breast cancer cells

Abstract In HER2-enriched (HER2E) breast cancer (BC), the dual HER2/EGFR inhibitor Lapatinib is a standard of care for advanced staged disease. Anti-HER2 therapies disrupt tumor progression through inhibition of the PI3K/AKT pathway. Some treated tumors will override inhibition by shifting to MAPK/ERK signaling to fuel cell growth, thus fostering resistance to anti-HER2 therapy. The tyrosine receptor kinase FGFR4 is included in the profile for a HER2E subtype. FGFR4 is overexpressed in ~30% of BC and can signal through PI3K/AKT and MAPK/ERK. Inhibitors for FGFR4 such as BLU554 are being investigated in phase I/II clinical trials for hepatocellular carcinoma, showing success in tumors that are positive for FGFR4’s preferred ligand FGF19. According to cBioPortal patient data, FGF19 is amplified in ~20% of BC, and has been shown to trigger an autocrine loop in triple negative BC through FGFR4. We examined BLU554 as a dual therapeutic with Lapatinib and dissected intracellular signaling stemming from the combination in HER2E BC. MDA-MB-453 BC cells (HER2+FGFR4+) were used for a dual strategy with BLU554 and Lapatinib. Cell viability assays were performed at matched doses, then as a dose response matrix, ranging from 0.1-20 µM. Findings were used for synergy analysis using synergyfinder.fimm.fi. Western blots determined protein activity in response to treatments. Ridaforolimus (mTOR inhibitor) was used in combination with either BLU554 or Lapatinib to assess MAPK/ERK and PI3K/AKT pathway crosstalk in MB-453 cells. Additionally, FGF19 was added to cells after a 2-hour pre-treatment to challenge BLU554 + Lapatinib and compare changes in signaling with FGF19 present. MB-453 cells treated with BLU554 decreased cell viability similarly to Lapatinib at 10 µM (65% [SD ± 3.3] and 63% [SD ± 2.1], respectively). Dual treatment decreased viability compared to single agents at all concentrations but the greatest difference was observed at 20 µM (38.5% in dual compared to Lapatinib [p-value = 0.00006]; 45.1% in dual compared to BLU554 [p-value = 0.00016]). Dose-response matrix of dual treatment yielded a ZIP synergy score of 16.852 ± 2.97 (>10 is synergistic), with the greatest synergy and inhibition at 10 µM and 20 µM of both drugs. BLU554 caused a therapeutic potency shift of Lapatinib, such that lower doses of Lapatinib (0.1 µM, 1 µM) are effective at higher doses of BLU554 (10 µM, 20 µM). Westerns of MB-453 with one dose of BLU554 increased phospho-ERK1/2 (pERK1/2) at 16- or 48-hr time points versus control, but when BLU554 was re-dosed then pERK1/2 was successfully inhibited. Both pAKT and pS6RP were increased by re-dosing BLU554. Cells treated for 2 hrs with Lapatinib decreased pAKT and pS6RP and did not change pERK, whereas a 2-hr treatment of BLU554 increased pAKT and decreased pERK. Dual treatment exhibited inhibition of ERK, AKT, 4EBP1, and S6RP phosphorylation all to a greater extent than single agents in combination with Ridaforolimus. Challenge by ectopic FGF19 of BLU554 + Lapatinib was unable to restore downstream signaling of AKT and ERK. BLU554 synergistically interacts with Lapatinib to decrease cell viability while increasing its therapeutic potency. Lapatinib primarily inhibits AKT signaling, whereas BLU554 targets ERK. Dual treatment simultaneously blocks MAPK/ERK and PI3K/AKT signaling and yields decreases of mTOR downstream effectors pS6RP and p4EBP1. These effects are maintained even when challenged with FGF19, suggesting that dual inhibition of FGFR4 and HER2 could prevent pathway activation from external stimuli. Citation Format: Jordan Beardsley, Joseph Goode, Deborah Altomare. Dual inhibition of FGFR4 and HER2/EGFR with Lapatinib improves targeting of Erk and Akt signaling in HER2+ breast cancer cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-23-09.

Seralutinib in adults with pulmonary arterial hypertension (TORREY): a randomised, double-blind, placebo-controlled phase 2 trial.

Morbidity and mortality in pulmonary arterial hypertension (PAH) remain high. Activation of platelet-derived growth factor receptor, colony stimulating factor 1 receptor, and mast or stem cell growth factor receptor kinases stimulates inflammatory, proliferative, and fibrotic pathways driving pulmonary vascular remodelling in PAH. Seralutinib, an inhaled kinase inhibitor, targets these pathways. We aimed to evaluate the efficacy and safety of seralutinib in patients with PAH receiving standard background therapy. The TORREY trial was a phase 2, randomised, multicentre, multinational, double-blind, placebo-controlled study. Patients with PAH from 40 hospital and community sites were randomly assigned 1:1 via interactive response technologies to receive seralutinib (60 mg twice daily for 2 weeks, then increased to 90 mg twice daily as tolerated) or placebo by dry powder inhaler twice daily for 24 weeks. Randomisation was stratified by baseline pulmonary vascular resistance (PVR; <800 dyne·s/cm5 and ≥800 dyne·s/cm5). Patients were eligible if classified as WHO Group 1 PH (PAH), WHO Functional Class II or III, with a PVR of 400 dyne·s/cm5 or more, and a 6 min walk distance of between 150 m and 550 m. The primary endpoint was change in PVR from baseline to 24 weeks. Analyses for efficacy endpoints were conducted in randomly assigned patients (intention-to-treat population). Safety analyses included all patients who received the study drug. TORREY was registered with ClinicalTrials.gov (NCT04456998) and EudraCT (2019-002669-37) and is completed. From Nov 12, 2020, to April 20, 2022, 151 patients were screened for eligibility, and following exclusions, 86 adults receiving PAH background therapy were randomly assigned to seralutinib (n=44; four male, 40 female) or placebo (n=42; four male, 38 female), and comprised the intention-to-treat population. At baseline, treatment groups were balanced except for a higher representation of WHO Functional Class II patients in the seralutinib group. The least squares mean change from baseline to week 24 in PVR was 21·2 dyne·s/cm5 (95% CI -37·4 to 79·8) for the placebo group and -74·9 dyne·s/cm5 (-139·7 to -10·2) for the seralutinib group. The least squares mean difference between the seralutinib and placebo groups for change in PVR was -96·1 dyne·s/cm5 (95% CI -183·5 to -8·8; p=0·03). The most common treatment-emergent adverse event in both treatment groups was cough: 16 (38%) of 42 patients in the placebo group; 19 (43%) of 44 patients in the seralutinib group. Treatment with inhaled seralutinib significantly decreased PVR, meeting the primary endpoint of the study among patients receiving background therapy for PAH. Gossamer Bio.

Cell wall-mediated root development is targeted by a soil-borne bacterial pathogen to promote infection

Plant pathogens manipulate host development, facilitating colonization and proliferation. Ralstonia solanacearum is a soil-borne bacterial pathogen that penetrates roots and colonizes plants through the vascular system, causing wilting and death. Here, we find that RipAC, an effector protein from R.solanacearum, alters root development in Arabidopsis, promoting the formation of lateral roots and root hairs. RipAC interacts with CELLULOSE SYNTHASE (CESA)-INTERACTIVE PROTEIN 1 (CSI1), which regulates the activity of CESA complexes at the plasma membrane. RipAC disrupts CESA-CSI1 interaction, leading to a reduction in cellulose content, root developmental alterations, and a promotion of bacterial pathogenicity. We find that CSI1 also associates with the receptor kinase FERONIA, forming a complex that negatively regulates immunity in roots; this interaction, however, is not affected by RipAC. Our work reveals a bacterial virulence strategy that selectively affects the activities of a host target, promoting anatomical alterations that facilitate infection without causing activation of immunity.

Immunohistochemistry of Lung Cancer Biomarkers.

Immunohistochemical (IHC) staining represents a comparatively inexpensive testing method that is attractive as a potential alternative to molecular sequencing methods or fluorescence in situ hybridization for pulmonary biomarker testing. While a variety of IHC tests directed at actionable genetic alterations have been developed and evaluated since the advent of targeted therapy, specific antibody clones for anaplastic lymphoma kinase, ROS-1, and potentially neurotrophic tropmyosin receptor kinase have been the primary antibodies that provide sufficiently robust results to be utilized as either a primary testing or screening method to direct targeted therapy. Antibodies for a variety of other targets such as epidermal growth factor receptors, for example, have lacked sufficient sensitivity and specificity to cover the range of mutations that may occur and are generally not recommended in lieu of molecular testing with the exception of limited resource settings. IHC is also used as a predictive marker for response to immunotherapy through evaluation of programmed death ligand 1 expression. In addition, multiple antibody-drug conjugates (ADCs) are under investigation, designed to deliver drugs directly to tumor cells through binding to specific target antigens. Some ADCs have already received accelerated FDA approval, and IHC was incorporated in many clinical trials evaluating ADC efficacy. As such, it is anticipated that ADCs may have a companion diagnostic IHC to guide patient selection.

Computational Analysis of Activation of Dimerized Epidermal Growth Factor Receptor Kinase Using the String Method and Markov State Model.

Epidermal growth factor receptor (EGFR) activation is accompanied by dimerization. During the activation of the intracellular kinase domain, two EGFR kinases form an asymmetric dimer, and one side of the dimer (receiver) is activated. Using the string method and Markov state model (MSM), we performed a computational analysis of the structural changes in the activation of the EGFR dimer in this study. The string method reveals the minimum free-energy pathway (MFEP) from the inactive to active structure. The MSM was constructed from numerous trajectories of molecular dynamics simulations around the MFEP, which revealed the free-energy map of structural changes. In the activation of the receiver kinase, the unfolding of the activation loop (A-loop) is followed by the rearrangement of the C-helix, as observed in other kinases. However, unlike other kinases, the free-energy map of EGFR at the asymmetric dimer showed that the active state yielded the highest stability and revealed how interactions at the dimer interface induced receiver activation. As the H-helix of the activator approaches the C-helix of the receiver during activation, the A-loop unfolds. Subsequently, L782 of the receiver enters the pocket between the G- and H-helices of the activator, leading to a rearrangement of the hydrophobic residues around L782 of the receiver, which constitutes a structural rearrangement of the C-helix of the receiver from an outward to an inner position. The MSM analysis revealed long-time scale trajectories via kinetic Monte Carlo.

Shared features underlying compact genomes and extreme habitat use in chironomid midges.

Non-biting midges (family Chironomidae) are found throughout the world in a diverse array of aquatic and terrestrial habitats, can often tolerate harsh conditions such as hypoxia or desiccation, and have consistently compact genomes. Yet we know little about the shared molecular basis for these attributes and how they have evolved across the family. Here, we address these questions by first creating high-quality, annotated reference assemblies for Tanytarsus gracilentus (subfamily Chironominae, tribe Tanytarsini) and Parochlus steinenii (subfamily Podonominae). Using these and other publicly available assemblies, we created a time-calibrated phylogenomic tree for family Chironomidae with outgroups from order Diptera. We used this phylogeny to test for features associated with compact genomes, as well as examining patterns of gene family evolution and positive selection that may underlie chironomid habitat tolerances. Our results suggest that compact genomes evolved in the common ancestor of Chironomidae and Ceratopogonidae, and that this occurred mainly through reductions in non-coding regions (introns, intergenic sequences, and repeat elements). Significantly expanded gene families in Chironomidae included biological processes that may relate to tolerance of stressful environments, such as temperature homeostasis, carbohydrate transport, melanization defense response, and trehalose transport. We identified several positively selected genes in Chironomidae, notably sulfonylurea receptor, CREB-binding protein, and protein kinase D. Our results improve our understanding of the evolution of small genomes and extreme habitat use in this widely distributed group.

Integrated genome-wide association and transcriptomic analysis to identify receptor kinase genes to stripe rust resistance in wheat germplasm from southwestern China

Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide. Identification of new and elite Pst-resistance loci or genes has the potential to enhance overall resistance to this pathogen. Here, we conducted an integrated genome-wide association study (GWAS) and transcriptomic analysis to screen for loci associated with resistance to stripe rust in 335 accessions from Yunnan, including 311 landraces and 24 cultivars. Based on the environmental phenotype, we identified 113 protein kinases significantly associated with Pst resistance using mixed linear model (MLM) and generalized linear model (GLM) models. Transcriptomic analysis revealed that 52 of 113 protein kinases identified by GWAS were up and down regulated in response to Pst infection. Among these genes, a total of 15 receptor kinase genes were identified associated with Pst resistance. 11 candidate genes were newly discovered in Yunnan wheat germplasm. Our results revealed that resistance alleles to stripe rust were accumulated in Yunnan wheat germplasm, implying direct or indirect selection for improving stripe rust resistance in elite wheat breeding programs.

Discovery of a Novel Orally Bioavailable FLT3-PROTAC Degrader for Efficient Treatment of Acute Myeloid Leukemia and Overcoming Resistance of FLT3 Inhibitors.

Fms-like tyrosine receptor kinase 3 (FLT3) proteolysis-targeting chimeras (PROTACs) represent a promising approach to eliminate the resistance of FLT3 inhibitors. However, due to the poor druggability of PROTACs, the development of orally bioavailable FLT3-PROTACs faces great challenges. Herein, a novel orally bioavailable FLT3-ITD degrader A20 with excellent pharmacokinetic properties was discovered through reasonable design. A20 selectively inhibited the proliferation of FLT3-ITD mutant acute myeloid leukemia (AML) cells and potently induced FLT3-ITD degradation through the ubiquitin-proteasome system. Notably, oral administration of A20 resulted in complete tumor regression on subcutaneous AML xenograft models. Furthermore, on systemic AML xenograft models, A20 could completely eliminate the CD45+CD33+ human leukemic cells in murine and significantly prolonged the survival time of mice. Most importantly, A20 exerted significantly improved antiproliferative activity against drug-resistant AML cells compared to existing FLT3 inhibitors. These findings suggested that A20 could serve as a promising drug candidate for relapsed or refractory AML.

PagPXYs improve drought tolerance by regulating reactive oxygen species homeostasis in the cambium of Populus alba × P. glandulosa

PXY (Phloem intercalated with xylem) is a receptor kinase required for directional cell division during the development of plant vascular tissue. Drought stress usually affects plant stem cell division and differentiation thereby limiting plant growth. However, the role of PXY in cambial activities of woody plants under drought stress is unclear. In this study, we analyzed the biological functions of two PXY genes (PagPXYa and PagPXYb) in poplar growth and development and in response to drought stress in a hybrid poplar (Populus alba × P. glandulosa, ‘84K’). Expression analysis indicated that PagPXYs, similar to their orthologs PtrPXYs in Populus trichocarpa, are mainly expressed in the stem vascular system, and related to drought. Interestingly, overexpression of PagPXYa and PagPXYb in poplar did not have a significant impact on the growth status of transgenic plants under normal condition. However, when treated with 8 % PEG6000 or 100 mM H2O2, PagPXYa and PagPXYb overexpressing lines consistently exhibited more cambium cell layers, fewer xylem cell layers, and enhanced drought tolerance compared to the non-transgenic control ‘84K’. In addition, PagPXYs can alleviate the damage caused by H2O2 to the cambium under drought stress, thereby maintaining the cambial division activity of poplar under drought stress, indicating that PagPXYs play an important role in plant resistance to drought stress. This study provides a new insight for further research on the balance of growth and drought tolerance in forest trees.

A group of L-type lectin receptor kinases function redundantly in mediating extracellular NAD(P) signaling in Arabidopsis.

An Arabidopsis mutant lacking several L-type lectin receptor kinases shows severely reduced NAD(P)-induced local and systemic immunity and biological induction of systemic acquired resistance.

Cytosolic ABA Receptor Kinases phosphorylate the D6 PROTEIN KINASE leading to its stabilization which promotes Arabidopsis growth.

The polar auxin transport is required for proper plant growth and development. D6 PROTEIN KINASE (D6PK) is required for the phosphorylation of PIN-FORMED (PIN) auxin efflux carriers to regulate auxin transport, while the regulation of D6PK stabilization is still poorly understood. Here, we found that Cytosolic ABA Receptor Kinases (CARKs) redundantly interact with D6PK, and the interactions are dependent on CARKs' kinase activities. Similarly, CARK3 also could interact with paralogs of D6PK, including D6PKL1, D6PKL2, and D6PKL3. The genetic analysis shows that D6PK acts the downstream of CARKs to regulate Arabidopsis growth, including hypocotyl, leaf area, vein formation, and the length of silique. Loss-of-function of CARK3 in overexpressing GFP-D6PK plants leads to reduce the level of D6PK protein, thereby rescues plant growth. In addition, the cell-free degradation assays indicate that D6PK is degraded through 26 S proteasome pathway, while the phosphorylation by CARK3 represses this process in cells. In summary, D6PK stabilization by the CARK family is required for auxin-mediated plant growth and development.

Phototoxicity avoidance is a potential therapeutic approach for retinal dystrophy caused by EYS dysfunction.

Inherited retinal dystrophies (IRDs) are progressive diseases leading to vision loss. Mutation in the eyes shut homolog (EYS) gene is one of the most frequent causes of IRD. However, the mechanism of photoreceptor cell degeneration by mutant EYS has not been fully elucidated. Here, we generated retinal organoids from induced pluripotent stem cells (iPSCs) derived from patients with EYS-associated retinal dystrophy (EYS-RD). In photoreceptor cells of RD organoids, both EYS and G protein-coupled receptor kinase 7 (GRK7), one of the proteins handling phototoxicity, were not in the outer segment, where they are physiologically present. Furthermore, photoreceptor cells in RD organoids were vulnerable to light stimuli, and especially to blue light. Mislocalization of GRK7, which was also observed in eys-knockout zebrafish, was reversed by delivering control EYS into photoreceptor cells of RD organoids. These findings suggest that avoiding phototoxicity would be a potential therapeutic approach for EYS-RD.

Hyperoside ameliorates depression-like behavior in ovariectomized mice

The physiological changes caused by the decline in estrogen levels due to menopause are linked to an increased risk of depression. This study investigated the antidepressant effects of hyperoside (HYP), a natural flavonol glycoside, and its associated molecular mechanisms in primary hippocampal neurons and ovariectomized (OVX) mice. HYP treatment increased nitric oxide (NO) production and neuronal nitric oxide synthase (nNOS) expression in primary hippocampal neurons; additionally, it upregulated the expression of brain-derived neurotrophic factor (BDNF) and phosphorylated tropomyosin receptor kinase B (TrkB). In OVX mice, HYP treatment significantly improved depression-like behaviors in an open field test to a level comparable to estrogen treatment. Furthermore, HYP treatment upregulated OVX-induced decreased nNOS expression and BDNF-TrkB signaling in the hippocampus. Therefore, this study suggests that HYP exhibits antidepressant potential by addressing estrogen deficiency-induced alterations, specifically by restoring nNOS expression, promoting NO production, and concurrently enhancing BDNF-TrkB signaling in OVX mice.

Pharmacological Evidence of Eugenia Brasiliensis Leaves in a Reserpine-Induced Fibromyalgia Model: Antinociceptive, Emotional, Anti-Inflammatory, and Neurotrophic Effects.

Fibromyalgia (FM) is a painful chronic condition that significantly impacts the quality of life, posing challenges for clinical management. Given the difficulty of understanding the pathophysiology and finding new therapeutics, this study explored the effects of a medicinal plant, E. brasiliensis, in an FM model induced by reserpine in Swiss mice. Animals were treated with saline 0.9% (vehicle), duloxetine 10 mg/kg (positive control), or hydroalcoholic extract of E. brasiliensis leaves 300 mg/kg (HEEb). Nociceptive parameters, as well as locomotion, motor coordination, strength, anxiety, and depressive-like behaviors, were evaluated for 10 days. After that, the brain and blood were collected for further analysis of cytokines (interleukin 1? and interleukin 6), brain-derived neurotrophic factor (BDNF), and the immunocontents of total and phosphorylated Tropomyosin receptor kinase B (TrkB). The results demonstrated that the acute and prolonged treatment with HEEb was able to reduce both mechanical and thermal nociception. It was also possible to observe an increase in the strength, without changing locomotion and motor coordination parameters. Interestingly, treatment with HEEb reduces anxious and depressive-like behaviors. Finally, we observed a reduction in inflammatory cytokines in the hippocampus of animals treated with HEEb, while an increase in BDNF was observed in the prefrontal cortex (PFC). However, no alterations related to total and phosphorylated TrkB receptor expression were found. Our study demonstrated the antinociceptive and emotional effects of HEEb in mice, possibly acting on neuroinflammatory and neurotrophic mechanisms. These data provide initial evidence about the E. brasiliensis potential for treating chronic pain.

Arabidopsis class A S-acyl transferases modify the pollen receptors LIP1 and PRK1 to regulate pollen tube guidance.

Protein S-acylation catalyzed by protein S-acyl transferases (PATs) is a reversible lipid modification regulating protein targeting, stability, and interaction profiles. PATs are encoded by large gene families in plants, and many proteins including receptor-like cytoplasmic kinases (RLCKs) and receptor-like kinases (RLKs) are subject to S-acylation. However, few PATs have been assigned substrates, and few S-acylated proteins have known upstream enzymes. We report that Arabidopsis (Arabidopsis thaliana) class A PATs redundantly mediate pollen tube guidance and participate in the S-acylation of POLLEN RECEPTOR KINASE1 (PRK1) and LOST IN POLLEN TUBE GUIDANCE1 (LIP1), a critical RLK or RLCK for pollen tube guidance, respectively. PAT1, PAT2, PAT3, PAT4, and PAT8, collectively named PENTAPAT for simplicity, are enriched in pollen and show similar subcellular distribution. Functional loss of PENTAPAT reduces seed set due to male gametophytic defects. Specifically, pentapat pollen tubes are compromised in directional growth. We determine that PRK1 and LIP1 interact with PENTAPAT, and their S-acylation is reduced in pentapat pollen. The plasma membrane (PM) association of LIP1 is reduced in pentapat pollen, whereas point mutations reducing PRK1 S-acylation affect its affinity with its interacting proteins. Our results suggest a key role of S-acylation in pollen tube guidance through modulating PM receptor complexes.

An odd dancing couple. Non-small cell lung carcinoma with coexisting EGFR mutation and NTRK-1 translocation: A case report.

In the 21st century, there has been a dramatic shift in the diagnosis and management of non-small cell lung carcinoma (NSCLC), with an increasing use of minimally invasive tissue acquisition methods. Current treatments require morphologic subtyping and biomarker information in all cases. Determining such biomarkers is a continuously evolving field; current guidelines state that the determination of mutations on the Epidermal Growth Factor (EFGR), Kirsten Rat Sarcoma viral oncogene homolog (KRAS), Proto-oncogene B-Raf (BRAF), Human epidermal growth factor receptor 2 (HER2) and Anaplastic Lymphoma Kinase (ALK), genes as well as fusions on genes such as ROS Proto-Oncogene 1, Receptor Tyrosine Kinase (ROS1), MET proto-oncogene, receptor tyrosine kinase (MET), RET proto-oncogene (RET), and the Neurotrophic Tyrosine Receptor Kinase (NTRK) family is mandatory. While analyzing such alterations, some of them were first reported to be mutually exclusive, although in recent years, it has been shown otherwise in some of these cases. Moreover, so was the case with the concomitant expression of NTRK fusions and EGFR mutations. We present a case report of a patient with concomitant EGFR mutation and NTRK1 fusion.