KIT Receptor Research Articles

MASSIVE GASTROINTESTINAL STROMAL TUMOR OF THE STOMACH. CLINICAL CASE

Gastrointestinal stromal tumors (GIST) are rare overall but the most common malignant mesenchymal tumors in the gastrointestinal tract. The decisive factor for the diagnosis in addition to objective symptoms is the expres­sion of the proto-oncogene KIT (CD117) receptor. The most common treatment is surgical resection, preceded by neoadjuvant therapy. In this clinical case we present a 55 year old patient’s who is diagnosed with a giant gastric GIST, effectiveness of systemic treatment.

Deciphering lipoprotein(a) atherogenicity with use of high-throughput proteomics

Abstract Background Accumulating observational and genetic evidence suggests that lipoprotein(a) [Lp(a)], is significantly more atherogenic than other apolipoprotein-B containing particles. Systemic inflammation is thought to mediate the atherogenic effects of Lp(a). Previous studies have predominantly focused on single inflammatory biomarkers, an approach that fails to capture the broader molecular response to elevated Lp(a) levels. Purpose The aim of this study was to derive a proteome-wide signature of plasma Lp(a) concentrations and subsequently identify the pathways through which Lp(a) influences the risk of coronary artery disease (CAD). Methods This study included 41,123 UK Biobank participants with baseline Lp(a) measurements who also underwent a proteomic assessment. Relative concentration of 2,920 proteins was quantified in EDTA plasma samples using a high-throughput proximity extension assay. Lp(a)-associated proteins were identified in linear regression models, adjusting for age, sex, body mass index, race, smoking status, estimated glomerular filtration rate, medication use, and apolipoprotein B. Proteins linked with Lp(a) concentration were then evaluated for their association with incident CAD risk using Cox proportional hazards models. Significant traits were further included in pathway enrichment analysis. Results Out of 2,920 analyzed proteins (Figure 1), 140 showed a positive association with Lp(a) concentration, while 336 exhibited a negative association after adjustment for multiple testing (False discovery rate < 0.05). The strongest positive associations were observed for apolipoprotein F, group 10 secretory phospholipase A, and C4b-binding protein beta chain. The strongest negative associations were observed for asporin, aminoacylase-1, and retinol-binding protein 5. Among 140 proteins positively associated with Lp(a), 49 were associated with an increased risk of CAD. Conversely, among the 336 proteins negatively associated with Lp(a), 10 were associated with a decreased risk of CAD. Pathway enrichment analysis (Figure 2) indicated that proteins linked with both Lp(a) levels and CAD risk predominantly upregulated pathways related to peptide-ligand receptor signalling, platelet degranulation, neutrophil degranulation, and cytosolic calcium response. Conversely, pathways related to HDL remodeling, PI3K/AKT, KIT, and nuclear receptor signalling were downregulated. Conclusions The greater atherogenic potential of Lp(a) may be attributable to the modulation of several molecular pathways, particularly those involving platelet and neutrophil responses, cell signalling, and lipoprotein metabolism.

Regulation of BCR-dependent germinal center B-cell formation by HGAL and insight into its emerging myeloid ortholog, C1ORF150.

The specificity of cytokine and immunoreceptor signaling frequently depends upon receptor recruitment of select adaptor proteins and specifically engaged effectors. This review focuses on the orthologous adaptor proteins, HGAL and C1ORF150, and aims to provide insight into their respective modulation of lymphoid and myeloid cell signaling, formation, and function. HGAL acts predominantly within germinal center B cells as an important BCR signal transducer. Effects on BCR signalosome assembly involve HGAL's localization to the plasma membrane via its lipidation, initial interactions with SYK, the pY-phosphorylation of HGAL including its recruitment of GRB2, and HGAL engagement of PDZ-RhoGEF and RhoA signaling. At ligated BCRs, this includes HGAL(-GRB2) stimulation of SYK kinase, attenuation of calcium flux-dependent and NF-κB expression, promotion of cSMAC formation, and cytoskeletal remodeling associated with HGAL-attenuated cell migration. HGAL and partnered effectors also impact on DLBCL pathogenesis, and studies are summarized on HGAL's actions (using DLBCL and Burkitt lymphoma B cells) including cell migration effects, HGAL modulation of cytoskeletal components, and insightful HGAL transgenic mouse and xenograft models. For C1ORF150, its HGAL-homologous subdomains are considered, together with studies that demonstrate C1OR150's FcϵRI- and KIT-mediated expression and phosphorylation in primary human mast cells. Intriguingly, recent GWAS studies have identified a C1ORF150 in-frame splice variant that is strongly associated with urticaria. Candidate mechanisms via which the encoded "C1ORF150-Δexon2" isoform affects mast cell degranulation are considered, including FcϵR1 and/or KIT receptor connections, and candidate "myristoylation switch" mechanisms.

Conditional heterozygous loss of kit receptor tyrosine kinase in neural crest cell lineage is associated with midline cleft lip and bifid nose deformity

ObjectivesThe receptor tyrosine kinase Kit is expressed in cells derived from the trunk neural crest (NC), such as melanocytes; however, its role in cranial NC cell development is not fully understood. MethodsWe investigated the effects of the heterozygous loss of Kit in NC cells during embryonic development by mating Kit2lox/+ mice with Wnt1-Cre mice to produce Wnt1-Cre; Kit2lox/+ embryos. In addition, Wnt1-Cre mice were mated with Rosa26R-yellow fluorescent protein (YFP) mice to visualize the tissue regions expressing Cre recombinase. Histological studies of the craniofacial regions of these mice were performed using samples from embryonic day (E) 12.5 and postnatal day (P) 1. Cellular apoptosis and proliferation were both analyzed through the immunostaining of tissue sections collected on E13.5 and E14.5 using anti-cleaved caspase 3 (CC3) to detect apoptosis and anti-Ki67 to detect proliferation. Cells from YFP-positive tissue regions of the facial areas of Wnt1-Cre; Kit+/+; Rosa26R–YFP embryos and Wnt1-Cre; Kit2lox/+; Rosa26R–YFP embryos collected on E12.5 and E15.5 were cultured and evaluated for cell proliferation. ResultsCompared with control littermates, Wnt1-Cre; Kit2lox/+ embryos exhibited midline cleft lip and bifid nose deformities. Substantial early (P1) postnatal lethality was observed in Wnt1-Cre; Kit2lox/+ mice, with none surviving to 3 weeks of age. YFP-positive cells from the maxillary regions of Wnt1-Cre; Kit2lox/+; Rosa26R–YFP embryos exhibited defective cell growth and self-renewal in vitro. ConclusionConditional heterozygous loss of Kit in Wnt1-Cre; Kit2lox/+ embryos is associated with craniofacial dysplasia and exhibit defective NC development in vitro and in vivo.

Single-cell RNA-Seq reveals the heterogeneity of fibroblasts within the tympanojugular paraganglioma microenvironment

Tympanojugular paragangliomas (TJP) originate from the parasympathetic ganglia in the lateral base of the skull. Although the cellular composition and oncogenic mechanisms of paragangliomas have been evaluated, a comprehensive transcriptomic atlas specific to TJP remains to be established to facilitate further investigations. In this study, single-cell RNA sequencing and whole-exome sequencing were conducted on six surgically excised TJP samples to determine their cellular composition and intratumoral heterogeneity. Fibroblasts were sub-classified into two distinct groups: myofibroblasts and fibroblasts associated with bone remodeling. Additionally, an elaborate regulatory and cell–cell communication network was determined, highlighting the multifaceted role of fibroblasts, which varies depending on expression transitions. The Kit receptor (KIT) signaling pathway mediated interactions between fibroblasts and mast cells, whereas robust connections with endothelial and Schwann cell-like cells were facilitated through the platelet-derived growth factor signaling pathway. These findings establish a foundation for studying the mechanisms underlying protumor angiogenesis and the specific contributions of fibroblasts within the TJP microenvironment. IL6 signaling pathway of fibroblasts interacting with macrophages and endothelial cells may be involved in tumor regrowth. These results enhance our understanding of fibroblast functionality and provide a resource for future therapeutic targeting of TJP.

Advancements and challenges in understanding gastrointestinal stromal tumors: A comprehensive review

The most common mesenchymal tumor affecting the gastrointestinal system is gastrointestinal stromal tumor (GIST). Although GISTs are a relatively new type of tumor, the under understanding of these tumors has increased quickly. Nevertheless, there is a dearth of research on this illness in India, and the majority of treatment plans are based on studies performed on populations outside of the nation. Since the 1990s, considerable progress has been made in our knowledge of the lineage of origin of the GIST domain. According to recent research, multipotent mesenchymal stem cells are the source of GISTs, which are thought to occur in 10-20 cases per million people annually. With the overexpression of the tyrosine kinase receptor KIT in intestinal Cajal cells, GISTs are the most prevalent malignant subepithelial lesions (SELs) in the digestive tract. GISTs can have a variety of morphologies, such as rhabdomyosarcoma, angiosarcoma, or undifferentiated pleomorphic sarcoma, which makes diagnosis difficult. However, new developments in molecular targeted therapy have transformed solid tumor oncology and provided exciting new avenues for treatment. To differentiate dedifferentiated GISTs from other gastrointestinal malignancies, this review paper will address current immunohistochemical markers and provide an outline of the morphologic and molecular features of these tumors. The findings also emphasize the importance of GIST genetic testing, progressive surgical approaches, adjuvant and neoadjuvant therapy for localized disorders, and metastatic condition-addressing methodologies. This article's major body explores the impact of imatinib therapy, the rarity of GISTs in pediatric patients, imaging methods for staging and monitoring, and difficulties with treating anorectal GISTs. This study highlights how crucial it is to pinpoint particular molecular subtypes to inform therapeutic choices for adjuvant and metastatic therapies.

USP5 Promotes Ripretinib Resistance in Gastrointestinal Stromal Tumors by MDH2 Deubiquition.

Ripretinib, a broad-spectrum inhibitor of the KIT and PDGFRA receptor tyrosine kinases, is designated as a fourth-line treatment for gastrointestinal stromal tumor (GIST). It is tailored for patients resistant to imatinib, sunitinib, and regorafenib. As its increasing use, instances of resistance to ripretinib are becoming more frequent. Unfortunately, there are currently no scientifically mature treatment options available for patients resistant to ripretinib. Posttranslational modifications (PTMs) such as ubiquitination, in conjunction with its interplay with other modifications, play a collective role in regulating tumor initiation and progression. However, the specific association between ubiquitination and ripretinib resistance is not reported. Through proteome-ubiquitinome sequencing, increased levels of the USP5 protein and decreased ubiquitination in ripretinib-resistant GISTs are detected. Subsequent examination of the mass spectrometry findings validated the interaction through which TRIM21 governs USP5 expression via ubiquitination, and USP5 regulates MDH2 expression through deubiquitination, consequently fostering ripretinib resistance in GIST. Moreover, ZDHHC18 can palmitoylate MDH2, preventing its ubiquitination and further increasing its protein stability. The research underscores the correlation between posttranslational modifications, specifically ubiquitination, and drug resistance, emphasizing the potential of targeting the USP5-MDH2 axis to counteract ripretinib resistance in GIST.

Hydrogen-rich water alleviates constipation by attenuating oxidative stress through the sirtuin1/nuclear factor-erythroid-2-related factor 2/heme oxygenase-1 signaling pathway.

Constipation, a highly prevalent functional gastrointestinal disorder, induces a significant burden on the quality of patients' life and is associated with substantial healthcare expenditures. Therefore, identifying efficient therapeutic modalities for constipation is of paramount importance. Oxidative stress is a pivotal contributor to colonic dysmotility and is the underlying pathology responsible for constipation symptoms. Consequently, we postulate that hydrogen therapy, an emerging and promising intervention, can serve as a safe and efficacious treatment for constipation. To determine whether hydrogen-rich water (HRW) alleviates constipation and its potential mechanism. Constipation models were established by orally loperamide to Sprague-Dawley rats. Rats freely consumed HRW, and were recorded their 24 h total stool weight, fecal water content, and charcoal propulsion rate. Fecal samples were subjected to 16S rDNA gene sequencing. Serum non-targeted metabolomic analysis, malondialdehyde, and superoxide dismutase levels were determined. Colonic tissues were stained with hematoxylin and eosin, Alcian blue-periodic acid-Schiff, reactive oxygen species (ROS) immunofluorescence, and immunohistochemistry for cell growth factor receptor kit (c-kit), PGP 9.5, sirtuin1 (SIRT1), nuclear factor-erythroid-2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). Quantitative real-time PCR and western blot analysis were conducted to determine the expression level of SIRT1, Nrf2 and HO-1. A rescue experiment was conducted by intraperitoneally injecting the SIRT1 inhibitor, EX527, into constipated rats. NCM460 cells were induced with H2O2 and treated with the metabolites to evaluate ROS and SIRT1 expression. HRW alleviated constipation symptoms by improving the total amount of stool over 24 h, fecal water content, charcoal propulsion rate, thickness of the intestinal mucus layer, c-kit expression, and the number of intestinal neurons. HRW modulated intestinal microbiota imbalance and abnormalities in serum metabolism. HRW could also reduce intestinal oxidative stress through the SIRT1/Nrf2/HO-1 signaling pathway. This regulatory effect on oxidative stress was confirmed via an intraperitoneal injection of a SIRT1 inhibitor to constipated rats. The serum metabolites, β-leucine (β-Leu) and traumatic acid, were also found to attenuate H2O2-induced oxidative stress in NCM460 cells by up-regulating SIRT1. HRW attenuates constipation-associated intestinal oxidative stress via SIRT1/Nrf2/HO-1 signaling pathway, modulating gut microbiota and serum metabolites. β-Leu and traumatic acid are potential metabolites that upregulate SIRT1 expression and reduce oxidative stress.

GASTRIC GASTROINTESTINAL STROMAL TUMOR WITH SUCCINATE DEHYDROGENASE B DEFICIENCY: CLINICAL CASE

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors found in the gastrointestinal tract, constituting a diverse group of c-Kit positive mesenchymal (stromal or connective tissue) tumors. Their development is primarily associated with mutations in the c-Kit proto-oncogene, leading to structural alterations in the type III transmembrane tyrosine kinase receptor (Kit). This receptor is crucial for regulating mitotic activity and cell differentiation. The activation of the Kit-receptor in tumor cells is identified through the expression of the immunohistochemical marker CD 117 (tyrosine kinase receptor protein), with approximately 80-90% of GISTs testing positive for CD 117. The objective of our study is to improve the diagnosis and treatment of gastrointestinal stromal tumors. The clinical case underscores the challenge of diagnosing gastrointestinal stromal tumors (GISTs) due to the absence of specific and definitive symptoms. In this instance, only radical surgical intervention facilitated an accurate diagnosis. Given the location of the tumor in the pyloric part of the gastric submucosal layer, a reliable biopsy during video esophagogastroduodenoscopy was unfeasible, as the gastric mucosa above the tumor appeared unaffected. Consequently, surgery with complete tumor excision and subsequent pathohistological and immunohistochemical analysis emerged as the primary diagnostic and therapeutic approach. These investigations confirmed the presence of a gastrointestinal stromal tumor of the stomach with succinate dehydrogenase B deficiency. In approximately 80% of GIST cases, succinate dehydrogenase deficiency plays a pivotal role. The absence of succinate dehydrogenase disrupts the Krebs cycle, leading to an accumulation of succinate, an oncometabolite that fuels carcinogenesis. Such tumors exhibit distinctive clinical characteristics, prognostic outcomes, and responsiveness to targeted therapies. Succinate dehydrogenase deficiency can arise from mutations or epigenomic alterations affecting gene expression. Notably, mutations or epigenomic disruptions in any succinate dehydrogenase subunit inevitably result in the loss of subunit B expression.

Meteorin-like protein/METRNL/Interleukin-41 ameliorates atopic dermatitis-like inflammation.

Meteorin-like protein (METRNL)/Interleukin-41 (IL-41) is a novel immune-secreted cytokine/myokine involved in several inflammatory diseases. However, how METRNL exerts its regulatory properties on skin inflammation remains elusive. This study aims to elucidate the functionality and regulatory mechanism of METRNL in atopic dermatitis (AD). METRNL levels were determined in skin and serum samples from patients with AD and subsequently verified in the vitamin D3 analogue MC903-induced AD-like mice model. The cellular target of METRNL activity was identified by multiplex immunostaining, single-cell RNA-seq and RNA-seq. METRNL was significantly upregulated in lesions and serum of patients with dermatitis compared to healthy controls (p <.05). Following repeated MC903 exposure, AD model mice displayed elevated levels of METRNL in both ears and serum. Administration of recombinant murine METRNL protein (rmMETRNL) ameliorated allergic skin inflammation and hallmarks of AD in mice, whereas blocking of METRNL signaling led to the opposite. METRNL enhanced β-Catenin activation, limited the expression of Th2-related molecules that attract the accumulation of Arginase-1 (Arg1)hi macrophages, dendritic cells, and activated mast cells. METRNL can bind to KIT receptor and subsequently alleviate the allergic inflammation of AD by inhibiting the expansion of immune cells, and downregulating inflammatory gene expression by regulating the level of active WNT pathway molecule β-Catenin.

Therapeutic modulation of KIT ligand in melanocytic disorders with implications for mast cell diseases.

KIT ligand and its associated receptor KIT serve as a master regulatory system for both melanocytes and mast cells controlling survival, migration, proliferation and activation. Blockade of this pathway results in cell depletion, while overactivation leads to mastocytosis or melanoma. Expression defects are associated with pigmentary and mast cell disorders. KIT ligand regulation is complex but efficient targeting of this system would be of significant benefit to those suffering from melanocytic or mast cell disorders. Herein, we review the known associations of this pathway with cutaneous diseases and the regulators of this system both in skin and in the more well-studied germ cell system. Exogenous agents modulating this pathway will also be presented. Ultimately, we will review potential therapeutic opportunities to help our patients with melanocytic and mast cell disease processes potentially including vitiligo, hair greying, melasma, urticaria, mastocytosis and melanoma.

Response of Male Reproductive System Against Ionizing Radiation and Available Radio-protective Agents: Cellular and Molecular Insight.

The reproductive organ, housing spermatogonial stem cells (SSCs), undergoes ongoing division impacted by the irradiation dosage and exposure duration. Within the male reproductive organ, germ stem cells (spermatogonia) and somatic cells (Sertoli and Leydig cells) are present. Lower doses of ionizing (>4-6 Gy) and non-ionizing radiation (radiofrequency and microwave range 900 MHz - 2.45 GHz) may cause sperm-related issues, while higher doses (15 Gy) may affect Leydig cells and testosterone production. Response to radiation varies with age and pubescence. Spermatogonial stem cells, crucial for regenerating the spermatogenic lineage, express molecular markers like Estrogen receptor, FSH (Follicular Stimulating Hormone) receptor, TLR-4 (Toll-like Receptor-4), TLR-5 (Toll-like Receptor-5), FGF2 (Fibroblast Growth Factor-2), KIT (Receptor Tyrosine Kinase), AT-1 (Angiotensin II Type-1 Receptor), LXRs-γ (Liver X Receptor-γ), TNF-β (Tumor Necrosis Factor-β), and PCNA (Proliferating Cell Nuclear Antigen), influencing stem cell activity in testes. This study aimed to review the various available radioprotective agents and their efficacy in targeting the male reproductive system from the available literature. Various radioprotective herbal/synthetic/microbial/metallic extracts/formulations/ drugs [Septilin, Silymarin, Organic Turmeric, Oestrogen, Melatonin, Febuxostat, SQGD (Semiquinone glucoside derivative), Rapamycin, Entolimod, Zinc, Selenium, etc.] have been investigated up to exposure, but owing to effectiveness issues, they are unable to fulfil the aim to the fullest of restoring male fertility and normal testosterone levels during such eventuality. Further study is needed to optimize these tactics and fill knowledge gaps. Also, the effective components of herbal, synthetic drugs, etc., should be isolated and tested up to clinical levels, paving the way for successful radioprotection and radiomitigation strategies in the male reproductive system.

A highly selective KIT inhibitor MOD000001 suppresses IgE-mediated mast cell activation

BackgroundThe KIT receptor tyrosine kinase and its ligand, stem cell factor (SCF) control proliferation and survival of mast cells. Thus, targeting KIT signaling may show promise for the treatment of allergic diseases involving mast cells. Recently, we discovered a new compound MOD000001 as a potential small-molecule KIT kinase inhibitor by using an in silico approach. ObjectiveThis study determined whether MOD000001 is highly-selective to KIT, inhibits KIT signaling in mast cells, and affects IgE-mediated mast cell activation. MethodsThe interaction of MOD000001 with 468 human kinases and its inhibitory activity against KIT were profiled and evaluated by using KinomeScan and cell-free kinase assays, respectively. The effects of MOD000001 on SCF-dependent signaling were examined by using primary mouse and human mast cells. The effects of MOD000001 on SCF-induced degranulation and passive cutaneous anaphylactic (PCA) reaction were examined in mice. ResultsMOD000001 interacted with KIT and inhibited KIT kinase activity with high selectivity. MOD000001 suppressed SCF-induced KIT signaling in mouse and human mast cells and in mice. PCA reaction was suppressed in mice treated with MOD000001 both for a short-term (1 week) and a long-term (7 weeks). Mice treated with MOD000001 for a long-term, but not for a short-term, showed skin mast cell reduction. ConclusionsMOD000001 is a highly selective KIT inhibitor that can suppress IgE-mediated mast cell activation in vivo. MOD000001 may do so by reducing tissue mast cell numbers or by other unknown mechanisms. The findings suggest potential benefits of MOD000001 for allergic diseases involving IgE-mediated mast cell activation.

Kit Ligand and Kit receptor tyrosine kinase sustain synaptic inhibition of Purkinje cells

The cell-type-specific expression of ligand/receptor and cell-adhesion molecules is a fundamental mechanism through which neurons regulate connectivity. Here, we determine a functional relevance of the long-established mutually exclusive expression of the receptor tyrosine kinase Kit and the trans-membrane protein Kit Ligand by discrete populations of neurons in the mammalian brain. Kit is enriched in molecular layer interneurons (MLIs) of the cerebellar cortex (i.e., stellate and basket cells), while cerebellar Kit Ligand is selectively expressed by a target of their inhibition, Purkinje cells (PCs). By in vivo genetic manipulation spanning embryonic development through adulthood, we demonstrate that PC Kit Ligand and MLI Kit are required for, and capable of driving changes in, the inhibition of PCs. Collectively, these works in mice demonstrate that the Kit Ligand/Kit receptor dyad sustains mammalian central synapse function and suggest a rationale for the affiliation of Kit mutation with neurodevelopmental disorders.

Kit Ligand and Kit receptor tyrosine kinase sustain synaptic inhibition of Purkinje cells.

The cell-type-specific expression of ligand/receptor and cell-adhesion molecules is a fundamental mechanism through which neurons regulate connectivity. Here, we determine a functional relevance of the long-established mutually exclusive expression of the receptor tyrosine kinase Kit and the trans-membrane protein Kit Ligand by discrete populations of neurons in the mammalian brain. Kit is enriched in molecular layer interneurons (MLIs) of the cerebellar cortex (i.e., stellate and basket cells), while cerebellar Kit Ligand is selectively expressed by a target of their inhibition, Purkinje cells (PCs). By in vivo genetic manipulation spanning embryonic development through adulthood, we demonstrate that PC Kit Ligand and MLI Kit are required for, and capable of driving changes in, the inhibition of PCs. Collectively, these works in mice demonstrate that the Kit Ligand/Kit receptor dyad sustains mammalian central synapse function and suggest a rationale for the affiliation of Kit mutation with neurodevelopmental disorders.

Prognostic nomogram in patients with gastrointestinal stromal tumors: a SEER-based study.

Gastrointestinal stromal tumor (GIST) is a common mesenchymal tumor of the gastrointestinal system. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Data from the Surveillance Epidemiology, and End Results (SEER) database of 1,213 patients diagnosed with GIST between 2010 and 2019 were dichotomized into a modeling set and a validation set at a 2:1 ratio. For the modeling set, both univariate and multivariate Cox regression analyses were used to identify independent prognostic factors. A nomogram was then constructed based on these determinants. Model efficacy was tested using receiver operating characteristic (ROC) curves, calibration curves, clinical decision curves, and risk stratification analysis in both subsets. Identified prognostic determinants included age, sex, pathological differentiation level, tumor-node-metastasis (TNM) stage, surgical intervention, radiotherapy, and marital status. The constructed nomogram showed area under the ROC curve (AUC) values of 0.822, 0.793, and 0.779 for 1-, 3-, and 5-year overall survival (OS) in the modeling set, respectively, while in the validation set, the values were 0.796, 0.823, and 0.806, respectively. Calibration plots from both sets confirmed the concordance between predicted and observed survival. Decision curve analysis (DCA) indicated significant clinical utility for the nomogram. Risk stratification of the patient data revealed distinct survival differences between high-risk and low-risk cohorts in both sets (P<0.001). A novel and potent nomogram for the prognosis of GIST has been introduced. This model's precision offers crucial insights for clinical decisions, yet further external validation remains essential.

A rare case presentation of neurofibromatosis type 1 with multiple gastrointestinal stromal tumors: a case report

Neurofibromatosis type 1 (NF1), a hereditary cancer predisposing syndrome is an autosomal dominant disorder. Gastrointestinal stromal tumor (GIST) is the most prevalent non-neurological tumor in these individuals. In NF1-associated GIST, KIT and platelet-derived growth factor receptor α (PDGFRA) mutations might not be present, and Imatinib may not be effective. Surgical resection is the first-line treatment. The primary aim was to include the possibility of rare tumors including GIST in neurofibromatosis patients in the differential diagnosis of GIT pathology/presentation. A 50-year-old male with neurofibromatosis came with complaints of dull aching abdominal pain and on further investigation was found to have lesions in the distal small bowel, suspicious of nerve sheath tumors, in abdominal computed tomography. A laparotomy was performed and the jejunum containing nodular lesions was resected and pathologically diagnosed as GIST. The patient was then started on Imatinib. At the 6-month follow-up, no tumor recurrence was visible. The rare and unusual location of multiple GIST in neurofibromatosis patients underscores its importance in differential diagnosis, and our case report on the patient's therapy and the clinical outcome could aid in patient care.

KIT-SNAP-tag/cell membrane chromatography model coupled with liquid chromatography-mass spectrometry for anti-GIST compound screening from Evodia rutaecarpa.

Gastrointestinal mesenchymal tumors, as the most common mesenchymal tumors in the gastrointestinal tract, are adjuvantly treated with multi-targeted tyrosine kinase inhibitors, such as imatinib and sunitinib, but there are problems of drug resistance and complex methods of monitoring therapeutic agents. The pathogenesis of this disease is related to mutations in tyrosine kinase (KIT) or platelet-derived growth factor receptor α, an important target for drug therapy. In recent years, the screening of relevant tyrosine kinase inhibitors from traditional Chinese medicine has become a hotspot in antitumor drug research. In the current study, the KIT-SNAP-tag cell membrane chromatography (KIT-SNAP-tag/CMC) column was prepared with satisfying specificity, selectivity, and reproducibility by chemically bonding high KIT expression cell membranes to thesilica gel surface using the SNAP-tag technology. The KIT-SNAP-tag/CMC-HPLC-MS two-dimensional coupling system was investigated using the positive drug imatinib, and the results showed that the system was a reliable model for screening potential antitumor compounds from complex systems. This system screened and identified three potential active compounds of evodiamine (EVO), rutaecarpin (RUT), and dehydroevodiamine (DEVO), which possibly target the KIT receptor, from the alcoholic extract of the traditional Chinese medicine Evodia rutaecarpa. Then, the KD values of the interaction of EVO, RUT, and DEVO with KIT receptors measured using nonlinear chromatography were 7.75 (±4.93) × 10-6, 1.42 (±0.71) × 10-6, and 2.34 (±1.86) × 10-6 mol/L, respectively. In addition, themethyl thiazolyl tetrazolium assay validated the active effects of EVO and RUT in inhibiting the proliferation of high KIT-expressing cells in the ranges of 0.1-10 µmol/L and 0.1-50 µmol/L, respectively. In conclusion, the KIT-SNAP-tag/CMC could be a reliable model for screening antitumor components from complex systems.

Inhibition of CSF1R and KIT With Pexidartinib Reduces Inflammatory Signaling and Cell Viability in Endometriosis.

Endometriosis is a common and debilitating disease, affecting ∼170 million women worldwide. Affected patients have limited therapeutic options such as hormonal suppression or surgical excision of the lesions, though therapies are often not completely curative. Targeting receptor tyrosine kinases (RTKs) could provide a nonhormonal treatment option for endometriosis. We determined that 2 RTKs, macrophage-colony stimulating factor 1 receptor (CSF1R) and mast/stem cell growth factor receptor KIT (KIT), are overexpressed in endometriotic lesions and could be novel nonhormonal therapeutic targets for endometriosis. The kinase activity of CSF1R and KIT is suppressed by pexidartinib, a small molecule inhibitor that was recently approved by the US Food and Drug Administration. Using immunohistochemistry, we detected CSF1R and KIT in endometriotic tissues obtained from peritoneal lesions, colorectal lesions, and endometriomas. Specifically, we show that KIT is localized to the epithelium of the lesions, while CSF1R is expressed in the stroma and macrophages of the endometriotic lesions. Given the high epithelial expression of CSF1R and KIT, 12Z endometriotic epithelial cells were used to evaluate the efficacy of dual CSF1R and KIT inhibition with pexidartinib. We found that pexidartinib suppressed activation in 12Z cells of JNK, STAT3, and AKT signaling pathways, which control key proinflammatory and survival networks within the cell. Using quantitative real-time polymerase chain reaction, we determined that pexidartinib suppressed interleukin 8 (IL8) and cyclin D1 (CCND1) expression. Lastly, we demonstrated that pexidartinib decreased cell growth and viability. Overall, these results indicate that pexidartinib-mediated CSF1R and KIT inhibition reduces proinflammatory signaling and cell viability in endometriosis.

Molecular Analysis of Murine KitK641E Melanoma Progression

Acral and mucosal melanomas are often driven by sequence variants in the KIT receptor tyrosine kinase, with nearly 40% harboring alterations in the KIT locus. Despite advances in the knowledge of KIT-mutated melanomas, little is known about the molecular reprogramming that occurs during KIT-mediated melanoma progression owing to the rarity of acral and mucosal melanomas and the lack of comprehensive biological tools and models. To this end, we used a murine model that allows us to ascertain the molecular underpinnings of the stages of cancer progression-transformation, tumorigenesis, immune engagement, and tumor escalation. We found dramatic increases in biosynthetic demands associated with the transformation stage, including DNA and RNA metabolism, leading to replication stress. Tumorigenesis was closely linked to neuronal and axonal development, likely necessary for invasion into the host. Immune engagement highlighted early immune excitation and rejection pathways, possibly triggered by abrupt neoantigen exposure. Finally, tumor escalation pathways proved consistent with immune evasion, with immune-related pathways becoming significantly downregulated. To our knowledge, it is previously unreported that these critical milestones needed for KIT-driven melanoma tumor formation have been studied at the molecular level using isogenically matched and phenotypically defined cells.