Stem Cell Factor Receptor C-kit Research Articles

The bone marrow endothelial progenitor cell response to septic infection.

Early increase in the level of endothelial progenitor cells (EPCs) in the systemic circulation occurs in patients with septic infection/sepsis. The significance and underlying mechanisms of this response remain unclear. This study investigated the bone marrow EPC response in adult mice with septic infection induced by intravenous injection (i.v.) of Escherichia coli. For in vitro experiments, sorted marrow stem/progenitor cells (SPCs) including lineage(lin)-stem cell factor receptor (c-kit)+stem cell antigen-1 (Sca-1)-, lin-c-kit+, and lin- cells were cultured with or without lipopolysaccharides (LPSs) and recombinant murine vascular endothelial growth factor (VEGF) in the absence and presence of anti-Sca-1 crosslinking antibodies. In a separate set of experiments, marrow lin-c-kit+ cells from green fluorescence protein (GFP)+ mice, i.v. challenged with heat-inactivated E. coli or saline for 24h, were subcutaneously implanted in Matrigel plugs for 5 weeks. Marrow lin-c-kit+ cells from Sca-1 knockout (KO) mice challenged with heat-inactivated E. coli for 24h were cultured in the Matrigel medium for 8 weeks. The marrow pool of EPCs bearing the lin-c-kit+Sca-1+VEGF receptor 2 (VEGFR2)+ (LKS VEGFR2+) and LKS CD133+VEGFR2+ surface markers expanded rapidly following septic infection, which was supported by both proliferative activation and phenotypic conversion of marrow stem/progenitor cells. Increase in marrow EPCs and their reprogramming for enhancing angiogenic activity correlated with cell-marked upregulation of Sca-1 expression. Sca-1 was coupled with Ras-related C3 botulinum toxin substrate 2 (Rac2) in signaling the marrow EPC response. Septic infection caused a substantial increase in plasma levels of IFN-γ, VEGF, G-CSF, and SDF-1. The early increase in circulating EPCs was accompanied by their active homing and incorporation into pulmonary microvasculature. These results demonstrate that the marrow EPC response is a critical component of the host defense system. Sca-1 signaling plays a pivotal role in the regulation of EPC response in mice with septic infection.

Network pharmacology combined with an animal model to reveal the material basis and mechanism of Amomum villosum in alleviating constipation in mice

Constipation is a prevalent gastrointestinal disorder, with its prevalence showing an annual upward trend. There are many factors involved in the occurrence of constipation, such as abnormal smooth muscle contraction and disorders of gastrointestinal hormone secretion. Amomum villosum (A. villosum) has been proven to be effective in improving digestive system diseases, but there is no report on improving constipation. Therefore, we used network pharmacology prediction combined with animal experiments to explore the key active components of A. villosum and their pharmacological mechanisms. The results of network pharmacological prediction showed that β-sitosterol was the key laxative compound of A. villosum, which may play a laxative role by activating the adrenoceptor alpha 1 A-myosin light chain (ADRA1A-MLC) pathway. Further animal experiments showed that β-sitosterol could significantly shorten the time to first black stool; increase faecal weight, faecal number, and faecal water content; and promote gastrointestinal motility. β-sitosterol may promote intestinal motility by upregulating the expression of ADRA1A and myosin light chain 9 (Myl9) mRNA and protein in the colon, thereby activating the ADRA1A-MLC signalling pathway. In addition, it is possible to improve constipation symptoms by regulating serum neurotransmitters and gastrointestinal motility-related factors, such as the serum content of 5-hydroxytryptamine (5-HT) and acetylcholinesterase (AchE) and the mRNA expression of 5-hydroxytryptamine receptor 4 (5-HT4), stem cell factor (SCF), stem cell factor receptor (c-Kit) and smooth muscle myosin light chain kinase (smMLCK) in the colon. These results lay a foundation for the application of A. villosum and β-sitosterol in constipation.

ATP/IL-33-Co-Sensing by Mast Cells (MCs) Requires Activated c-Kit to Ensure Effective Cytokine Responses.

Mast cells (MCs) are sentinel cells which represent an important part of the first line of defense of the immune system. MCs highly express receptors for danger-associated molecular patterns (DAMPs) such as the IL-33R and P2X7, making MCs to potentially effective sensors for IL-33 and adenosine-triphosphate (ATP), two alarmins which are released upon necrosis-induced cell damage in peripheral tissues. Besides receptors for alarmins, MCs also express the stem cell factor (SCF) receptor c-Kit, which typically mediates MC differentiation, proliferation and survival. By using bone marrow-derived MCs (BMMCs), ELISA and flow cytometry experiments, as well as p65/RelA and NFAT reporter MCs, we aimed to investigate the influence of SCF on alarmin-induced signaling pathways and the resulting cytokine production and degranulation. We found that the presence of SCF boosted the cytokine production but not degranulation in MCs which simultaneously sense ATP and IL-33 (ATP/IL-33 co-sensing). Therefore, we conclude that SCF maintains the functionality of MCs in peripheral tissues to ensure appropriate MC reactions upon cell damage, induced by pathogens or allergens.

Effect of Youthful Blood Environment and Its Key Stem Cell Factor on Renal Interstitial Fibrosis in Elderly Mice

Introduction: Youthful blood environment was shown to decelerate the aging process of the kidney and to attenuate senile renal fibrosis in a young-old parabiotic animal model; in addition, we identified a stem cell factor (SCF) that is closely linked with the process. This research was to investigate the effect of youthful blood environment on senile renal interstitial fibrosis and the role of SCF. Methods: We bred SCF receptor c-Kit gene loss-of-function Wps/Wps mice and established a combination mice model that was subjected to unilateral ureteral obstructive (UUO) and parabiotic surgeries. Parabiotic mice were divided into isochronic parabiotic (young-young [Y-IP] and old-old [O-IP]) and heterochronic parabiotic (young-old [HP]) groups. UUO surgery was performed in one of the parabiotic pairs in the IP group (Y-IPuuo and O-IPuuo) and in the elderly mice in the HP group (O-HPuuo). In order to study the role of SCF/c-kit on renal interstitial fibrosis, UUO surgery was performed in wildtype (WT) and Wps/Wps mice. Results: Fourteen days after UUO surgery, the kidney interstitial fibrosis area, kidney function, and the expressions of SCF/c-Kit, pNF-κB, and fibrosis-related proteins in the O-HPuuo group were significantly lower than those in the Ouuo and O-IPuuo groups. Compared with WT UUO mice, the expressions of pNF-κB and fibrosis-related proteins and the kidney function were all significantly decreased in Wps/Wps UUO mice. Conclusion: Youthful blood environment downregulated the expressions of SCF/c-Kit in elderly UUO mice and ameliorated UUO-induced kidney fibrosis and function loss.

The Role of Stem Cell Factor, Epidermal Growth Factor and Angiopoietin-2 in HBV, HCV, HCC and NAFLD.

Growth factors play a significant role in the immunopathogenesis of liver diseases, especially in liver fibrosis and cirrhosis. They can also play a role in liver regeneration and tissue repair. The regenerative capacity of the liver has been well established. Molecular mechanisms leading to regeneration involve a complex network of diverse molecules. Chronic liver injury leads to the dysregulation of regenerative mechanisms in the liver that, in addition to molecular oncogenesis, lead to uncontrolled cell proliferation and development of hepatocellular carcinoma (HCC). Stem cell factor (SCF), epidermal growth factor (EGF) and Angiopietin-2 (Ang-2) have been shown to be extremely important in the pathogenesis of liver diseases, and given their role in hepatitis B (HBV) or C virus (HCV), HCC and nonalcoholic fatty liver disease (NAFLD), they seem to be potential targets for future research into antifibrotic drugs. The role of SCF receptor c-kit in the liver is debatable, as it has impact on both liver regeneration and liver disease. EGF is a potential indicator of the survival of patients with HCC and can be a biomarker and therapeutic target structure in HCC. Further research is needed to investigate the potential role of Ang-2 for NAFLD associated with liver damage as a non-invasive circulating biomarker.

Cymbopogon citratus (DC.) Stapf aqueous extract ameliorates loperamide-induced constipation in mice by promoting gastrointestinal motility and regulating the gut microbiota.

Slow transit constipation (STC) is the most common type of functional constipation. Drugs with good effects and few side effects are urgently needed form the treatment of STC. Cymbopogon citratus (DC.) Stapf (CC) is an important medicinal and edible spice plant. The wide range of biological activities suggested that CC may have laxative effects, but thus far, it has not been reported. In this study, the loperamide-induced STC mouse model was used to evaluate the laxative effect of the aqueous extract of CC (CCAE), and the laxative mechanism was systematically explored from the perspectives of the enteric nervous system (ENS), neurotransmitter secretion, gastrointestinal motility factors, intestinal inflammation, gut barrier and gut microbiota. The results showed that CCAE not only decreased the serum vasoactive intestinal polypeptide (VIP), induced nitric oxide synthases (iNOS), and acetylcholinesterase (AchE) in STC mice but also increased the expression of gastrointestinal motility factors in colonic interstitial cells of Cajal (ICCs) and smooth muscle cells (SMCs), thereby significantly shortening the defecation time and improving the gastrointestinal transit rate. The significantly affected gastrointestinal motility factors included stem cell factor receptor (c-Kit), stem cell factor (SCF), anoctamin 1 (Ano1), ryanodine receptor 3 (RyR3), smooth muscle myosin light chain kinase (smMLCK) and Connexin 43 (Cx43). Meanwhile, CCAE could repair loperamide-induced intestinal inflammation and intestinal barrier damage by reducing the expression of the pro-inflammatory factor IL-1β and increasing the expression of the anti-inflammatory factor IL-10, chemical barrier (Muc-2) and mechanical barrier (Cldn4, Cldn12, Occludin, ZO-1, and ZO-2). Interestingly, CCAE could also partially restore loperamide-induced gut microbial dysbiosis in various aspects, such as microbial diversity, community structure and species composition. Importantly, we established a complex but clear network between gut microbiota and host parameters. Muribaculaceae, Lachnospiraceae and UCG-010 showed the most interesting associations with the laxative phenotypes; several other specific taxa showed significant associations with serum neurotransmitters, gastrointestinal motility factors, intestinal inflammation, and the gut barrier. These findings suggested that CCAE might promote intestinal motility by modulating the ENS-ICCs-SMCs network, intestinal inflammation, intestinal barrier and gut microbiota. CC may be an effective and safe therapeutic choice for STC.

Discovery and Anticancer Activity of Novel 1,3,4-Thiadiazole- and Aziridine-Based Indolin-2-ones via In Silico Design Followed by Supramolecular Green Synthesis.

Three crucial anticancer scaffolds, namely indolin-2-one, 1,3,4-thiadiazole, and aziridine, are explored to synthesize virtually screened target molecules based on the c-KIT kinase protein. The stem cell factor receptor c-KIT was selected as target because most U.S. FDA-approved receptor tyrosine kinase inhibitors bearing the indolin-2-one scaffold profoundly inhibit c-KIT. Molecular hybrids of indolin-2-one with 1,3,4-thiadiazole (IIIa–m) and aziridine (VIa and VIc) were afforded through a modified Schiff base green synthesis using β-cyclodextrin-SO3H in water as a recyclable proton-donor catalyst. A computational study found that indolin-2,3-dione forms a supramolecular inclusion complex with β-cyclodextrin-SO3H through noncovalent interactions. A molecular docking study of all the synthesized compounds was executed on the c-KIT kinase domain, and most compounds displayed binding affinities similar to that of Sunitinib. On the basis of the pharmacokinetic significance of the aryl thioether linkage in small molecules, 1,3,4-thiadiazole hybrids (IIIa–m) were extended to a new series of 3-((5-(phenylthio)-1,3,4-thiadiazol-2-yl)imino)indolin-2-ones (IVa–m) via thioetherification using bis(triphenylphosphine)palladium(II)dichloride as the catalyst for C–S bond formation. Target compounds were tested against NCI-60 human cancer cell lines for a single-dose concentration. Among all three series of indolin-2-ones, the majority of compounds demonstrated broad-spectrum activity toward various cancer cell lines. Compounds IVc and VIc were further evaluated for a five-dose anticancer study. Compound IVc showed a potent activity of IC50 = 1.47 μM against a panel of breast cancer cell lines, whereas compound VIc exhibited the highest inhibition for a panel of colon cancer cell lines at IC50 = 1.40 μM. In silico ADME property descriptors of all the target molecules are in an acceptable range. Machine learning algorithms were used to examine the metabolites and phase I and II regioselectivities of compounds IVc and VIc, and the results suggested that these two compounds could be potential leads for the treatment of cancer.

Imatinib Mesylate Reduces Neurotrophic Factors and pERK and pAKT Expression in Urinary Bladder of Female Mice With Cyclophosphamide-Induced Cystitis.

Imatinib mesylate is a tyrosine kinase inhibitor that inhibits platelet-derived growth factor receptor (PDGFR)-α, -β, stem cell factor receptor (c-KIT), and BCR-ABL. PDGFRα is expressed in a subset of interstitial cells in the lamina propria (LP) and detrusor muscle of the urinary bladder. PDGFRα + interstitial cells may contribute to bladder dysfunction conditions such as interstitial cystitis/bladder pain syndrome (IC/BPS) or overactive bladder (OAB). We have previously demonstrated that imatinib prevention via oral gavage or treatment via intravesical infusion improves urinary bladder function in mice with acute (4 hour, h) cyclophosphamide (CYP)-induced cystitis. Here, we investigate potential underlying mechanisms mediating the bladder functional improvement by imatinib using a prevention or treatment experimental design. Using qRT-PCR and ELISAs, we examined inflammatory mediators (NGF, VEGF, BDNF, CCL2, IL-6) previously shown to affect bladder function in CYP-induced cystitis. We also examined the distribution of phosphorylated (p) ERK and pAKT expression in the LP with immunohistochemistry. Imatinib prevention significantly (0.0001 ≤ p ≤ 0.05) reduced expression for all mediators examined except NGF, whereas imatinib treatment was without effect. Imatinib prevention and treatment significantly (0.0001 ≤ p ≤ 0.05) reduced pERK and pAKT expression in the upper LP (U. LP) and deeper LP (D. LP) in female mice with 4 h CYP-induced cystitis. Although we have previously demonstrated that imatinib prevention or treatment improves bladder function in mice with cystitis, the current studies suggest that reductions in inflammatory mediators contribute to prevention benefits of imatinib but not the treatment benefits of imatinib. Differential effects of imatinib prevention or treatment on inflammatory mediators may be influenced by the route and frequency of imatinib administration and may also suggest other mechanisms (e.g., changes in transepithelial resistance of the urothelium) through which imatinib may affect urinary bladder function following CYP-induced cystitis.

Screening and Analysis of Potential Critical Gene in Acute Myocardial Infarction Based on a miRNA-mRNA Regulatory Network.

BackgroundMicroRNAs (miRNAs) have been shown to be involved in the initiation, progression, and prevention of acute myocardial infarction (AMI), but the underlying mechanism remains unclear.ObjectiveThrough the GEO database, bioinformatics methods were used to explore the miRNA-mRNA regulatory relationship pairs associated with AMI and to elucidate the underlying mechanism.MethodsUsing the R software Limma package, differential expression analysis was performed using the AMI-related miRNA chip dataset (GSE31568) and mRNA chip dataset (GSE159657) from the GEO database. The miRDB, miRWalk, miRTarBase, and TargetScan databases were used to predict potential downstream target genes regulated by differentially expressed miRNAs, and a miRNA-mRNA regulatory network was built with Cytoscape; GO function and KEGG pathway enrichment analyses of target genes were done with Funrich software, and the protein interaction network of target genes in the regulatory network was built with the STRING database.Results and ConclusionsA total of 187 differentially expressed miRNAs were experimentally screened, of which 91 were upregulated (such as hsa-miR-302b, hsa-miR-1299), and 96 were downregulated (such as hsa-miR-1201, hsa-miR-1283); 507 differentially expressed mRNAs were identified, of which 430 were upregulated (such as MRM1 and SFXN4), and 77 were downregulated (such as KCTD13 and CCDC134). And 16 miRNAs and 44 mRNAs were used for regulatory network construction. GO and KEGG enrichment analyses mainly focused on Integrins in angiogenesis, angiopoietin receptor Tie2-mediated signaling, and signaling events mediated by stem cell factor receptor (c-Kit). As hub genes in the PPI network, FGF2 and MMP2 may be key targets of AMI. The experimentally constructed miRNA-mRNA regulatory network found that hsa-miR-190b targets to inhibit FGF2, while hsa-miR-330-3p targets to regulate MMP2, which may mediate Integrins in angiogenesis, Angiopoietin receptor Tie2-mediated signaling pathway to induce AMI pathogenesis, providing strong data support and a research direction for the prevention and treatment of AMI.

TORREY, a Phase 2 study to evaluate the efficacy and safety of inhaled seralutinib for the treatment of pulmonary arterial hypertension.

Aberrant kinase signaling that involves platelet-derived growth factor receptor (PDGFR) α/β, colony stimulating factor 1 receptor (CSF1R), and stem cell factor receptor (c-KIT) pathways may be responsible for vascular remodeling in pulmonary arterial hypertension. Targeting these specific pathways may potentially reverse the pathological inflammation, cellular proliferation, and fibrosis associated with pulmonary arterial hypertension progression. Seralutinib (formerly known as GB002) is a novel, potent, clinical stage inhibitor of PDGFRα/β, CSF1R, and c-KIT delivered via inhalation that is being developed for patients with pulmonary arterial hypertension. Here, we report on an ongoing Phase 2 randomized, double-blind, placebo-controlled trial (NCT04456998) evaluating the efficacy and safety of seralutinib in subjects with World Health Organization Group 1 Pulmonary Hypertension who are classified as Functional Class II or III. A total of 80 subjects will be enrolled and randomized to receive either study drug or placebo for 24 weeks followed by an optional 72-week open-label extension study. The primary endpoint is the change from baseline to Week 24 in pulmonary vascular resistance by right heart catheterization. The secondary endpoint is the change in distance from baseline to Week 24 achieved in the 6-min walk test. A computerized tomography sub-study will examine the effect of seralutinib on pulmonary vascular remodelling. A separate heart rate monitoring sub-study will examine the effect of seralutinib on cardiac effort during the 6-min walk test.

Intralesional platelet-rich plasma injection promotes tongue regeneration following partial glossectomy in a murine model

BackgroundWe examined the regenerative efficacy of the activated platelet-rich plasma (PRP) concentrate administered by local injection in an animal model mimicking partial glossectomy for tongue cancer. MethodsFour-week-old mice were randomized to four groups; (1) a treatment-naïve control group, (2) a PRP group, (3) a hemiglossectomy group, and (4) a hemiglossectomy + PRP group. The activated PRP concentrate was injected into the deep layer of resected surfaces of mouse tongues immediately after excision, and tongue widths and lengths were measured on postoperative days (POD) 5 and 12. Gross tongue morphologies and microscopic findings were investigated. Inflammation and fibrous tissue areas were also measured, and immunohistochemical analysis was performed for c-kit, neurofilament, and S-100. ResultsThe activated PRP concentrate reduced wound scar contracture, promoted wound healing, and reduced inflammation and wound fibrosis. On POD 12, histologic findings in the hemiglossectomy + PRP group were similar to those in the normal control group, and the intensity of stem cell factor receptor c-kit expression was also significantly greater in the PRP group than in the hemiglossectomy group on POD 12. Immunohistochemical staining revealed S100 and neurofilament expressions in the hemiglossectomy + PRP group were significantly more intense than in the hemiglossectomy group. ConclusionIntralesional activated PRP concentrate injection has potential use for tongue regeneration, wound healing, and neural regeneration with minimal scarring after partial glossectomy.

Efficacy and Safety of Anti-PD-1 Plus Anlotinib in Patients With Advanced Non–Small-Cell Lung Cancer After Previous Systemic Treatment Failure—A Retrospective Study

BackgroundPre-clinical and clinical evidences support that simultaneous blockade of programmed death-1 (PD-1) and vascular endothelial growth factor receptor (VEGFR) can enhance antigen-specific T-cell migration, and show tolerable toxicity with favorable antitumor activity in patients. In this study, we aimed to assess the safety and efficacy of anlotinib, a novel multitarget tyrosine kinase inhibitor for VEGFR, platelet-derived growth receptor (PDGFR), and the stem cell-factor receptor (c-Kit), combined with anti-PD-1 treatment in patients with advanced NSCLC.MethodsSixty-seven patients with previously treated advanced NSCLC receiving anti-PD-1 agents concomitant with anlotinib were retrospectively enrolled in an IRB approved study. Anti-PD-1 agents including pembrolizumab, nivolumab, camrelizumab, toripalimab, sintilimab, and tislelizumab were administered every two or three weeks until disease progression or unacceptable toxicity was reached. Anlotinib was administered orally once daily on days 1–14 of a 21-day cycle. The safety and tolerability of the combination treatment were assessed by the incidence of adverse events. The efficacy of the treatment was assessed by the tumor response and survival.ResultsWith a median follow-up period of 8.7 months, treatment-related adverse events occurred in 85% (57/67) of patients and grade 3–4 adverse events were observed in 27 patients (40%). No unexpected adverse events or significantly increased toxicities were observed. Complete response was not observed, 19 patients had partial response (28.4%), 39 had stable disease (58.2%) and 9 had progressive disease (13.4%). The overall response (ORR) and disease control rates (DCR) were 28.4% and 86.6%, respectively. The median progression-free survival (PFS) was 6.9 months (95% CI, 5.5-8.3 months) and overall survival (OS) was 14.5 months (95% CI, 10.9-18.1 months). The benefit of anti-PD-1 plus anlotinib was also observed in patients with EGFR mutation positive, liver metastases and brain metastases.ConclusionAnti-PD-1 treatment concomitant with anlotinib has tolerable toxicity and favorable antitumor activity in patients with previously treated advanced NSCLC. Our results add to the growing evidence that supports the benefits of combining immunotherapy with antiangiogenic drugs. This combination could be further evaluated with or without chemotherapy, since no additional toxicity was observed in the combination treatment.

Molecular Modeling Study of c-KIT/PDGFRα Dual Inhibitors for the Treatment of Gastrointestinal Stromal Tumors.

Gastrointestinal stromal tumors (GISTs) are the most common Mesenchymal Neoplasm of the gastrointestinal tract. The tumorigenesis of GISTs has been associated with the gain-of-function mutation and abnormal activation of the stem cell factor receptor (c-KIT) and platelet-derived growth factor receptor alpha (PDGFRα) kinases. Hence, inhibitors that target c-KIT and PDGFRα could be a therapeutic option for the treatment of GISTs. The available approved c-KIT/PDGFRα inhibitors possessed low efficacy with off-target effects, which necessitated the development of potent inhibitors. We performed computational studies of 48 pyrazolopyridine derivatives that showed inhibitory activity against c-KIT and PDGFRα to study the structural properties important for inhibition of both the kinases. The derivative of phenylurea, which has high activities for both c-KIT (pIC50 = 8.6) and PDGFRα (pIC50 = 8.1), was used as the representative compound for the dataset. Molecular docking and molecular dynamics simulation (100 ns) of compound 14 was performed. Compound 14 showed the formation of hydrogen bonding with Cys673, Glu640, and Asp810 in c-KIT, and Cys677, Glu644, and Asp836 in PDGFRα. The results also suggested that Thr670/T674 substitution in c-KIT/PDGFRα induced conformational changes at the binding site of the receptors. Three-dimensional quantitative structure–activity relationship (3D-QSAR) models were developed based on the inhibitors. Contour map analysis showed that electropositive and bulky substituents at the para-position and the meta-position of the benzyl ring of compound 14 was favorable and may increase the inhibitory activity against both c-KIT and PDGFRα. Analysis of the results suggested that having bulky and hydrophobic substituents that extend into the hydrophobic pocket of the binding site increases the activity for both c-KIT and PDGFRα. Based on the contour map analysis, 50 compounds were designed, and the activities were predicted. An evaluation of binding free energy showed that eight of the designed compounds have potential binding affinity with c-KIT/PDGFRα. Absorption, distribution, metabolism, excretion and toxicity (ADMET) and synthetic feasibility tests showed that the designed compounds have reasonable pharmaceutical properties and synthetic feasibility. Further experimental study of the designed compounds is recommended. The structural information from this study could provide useful insight into the future development of c-KIT and PDGFRα inhibitors.

Stem Cell Factor Receptor Immunoexpression in Adolescent Varicocele.

Stem cell factor receptor (c-kit) plays a crucial role in regulating proliferation and survival of germ cells. The aim of this study was to find the correlation between the number of c-kit positive germ cells, testicular asymmetry and histological grade in varicocele affected testis samples of adolescents. Twenty testicular biopsy samples of adolescents affected by varicocele and eight normal control testes were included. The relationship between percentage of testicular asymmetry, number of tubular c-kit positive germ cells and severity of spermatogenic failure was assessed. The mean (SD; median) histological grade for spermatogenic failure in controls was 1.37(0.52; 1), while in the varicocele group, it was 2.70(1.08; 3) (P = .0052). Mean(SD; median) number c-kit positive germ cells in the control group were 20.1(2.52; 20), while in the varicocele group it was 12.35(7.16; 12.5) (P = .0059). Spearman test documented a significant positive correlation between percentage of hypotrophy and histological grade of spermatogenic failure (r = 0.5544 , 95% CI: 0.1345 to 0.8055, P = .0112) but a negative correlation with the number of c-kit positive cells (r = - 0.5871, 95% CI: - 0.8219 to -0.1817, P = .0065). Moreover, a significant negative correlation was found between grade of histological changes and number of c-kit positive germ cells (P < .0001). A significant correlation between hypotrophy, histological lesions and c-kit positive germ cells exists in varicocele testes. This finding suggests a possible role for c-kit in the pathogenesis of germ cell impairment in varicocele. Histological changes and lack of c-kit germ cells were also noted in testes not displaying hypotrophy. We believe that reliable markers should be found as better predictors of testicular function in adolescent with varicocele.

Immunohistochemical study assessing stem cell factor receptor C-kit in patients with alopecia

Background Stem cell factor receptor c-kit is a transmembrane protein with tyrosine kinase activity encoded by the oncogene c-kit. The stem cell factor/c-kit signaling may be involved in the pathological processes of alopecia. Objective The aim was to elucidate the role of the stem cell factor receptor c-kit in the pathogenesis of some types of alopecia. Patients and methods The study included 80 patients (52 had alopecia areata and 28 had androgenetic alopecia), in addition to 40 normal healthy persons who served as a control group. Skin biopsies were obtained from each participant and stained with hematoxylin and eosin and stem cell factor receptor c-kit. Results There was a statistically significant increase in intensity and count of stem cell factor receptor c-kit-positive cell expression in alopecia areata and androgenetic alopecia than in normal control specimens. There was a positive correlation between the intensity and count of stem cell factor receptor c-kit-positive cells in relation to the severity of alopecia. Conclusions Stem cell factor receptor c-kit was implicated in the pathogenesis of alopecia areata and androgenic alopecia, and it could have a predictive role in the progression of alopecia in high-risk patients.

Identification of a Multitargeted Tyrosine Kinase Inhibitor for the Treatment of Gastrointestinal Stromal Tumors and Acute Myeloid Leukemia.

Gastrointestinal stromal tumors (GISTs) are prototypes of stem cell factor receptor (c-KIT)-driven cancer. Two receptor tyrosine kinases, c-KIT and fms-tyrosine kinase (FLT3), are frequently mutated in acute myeloid leukemia (AML) patients, and these mutations are associated with poor prognosis. In this study, we discovered a multitargeted tyrosine kinase inhibitor, compound 15a, with potent inhibition against single or double mutations of c-KIT developed in GISTs. Moreover, crystal structure analysis revealed the unique binding mode of 15a with c-KIT and may elucidate its high potency in inhibiting c-KIT kinase activity. Compound 15a inhibited cell proliferation and induced apoptosis by targeting c-KIT in c-KIT-mutant GIST cell lines. The antitumor effects of 15a were also demonstrated in GIST430 and GIST patient-derived xenograft models. Further studies demonstrated that 15a inhibited the proliferation of c-KIT- and FLT3-driven AML cells in vitro and in vivo. The results of this study suggest that 15a may be a potential anticancer drug for the treatment of GISTs and AML.

The efficacy and safety of anlotinib treatment for advanced lung cancer.

ObjectiveAnlotinib is an oral novel multi-target tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor, fibroblast growth factor receptor, platelet-derived growth factor receptor, and stem cell factor receptor (c-Kit). The aim of this study was to evaluate the efficacy and safety of anlotinib treatment in advanced lung cancer in the real world.MethodsWe evaluated the efficacy and toxicity of apatinib in patients with previously treated advanced lung cancer from 2018 to 2019 in Zhejiang Cancer Hospital. Survival analysis was performed by the Kaplan–Meier method.ResultsFifty-eight patients were included in the present study. Thirty-one of these patients received anlotinib treatment as a third line and 27 patients received further therapy. All 58 patients had therapeutic evaluation and 46 patients acquired progression-free survival evaluation. Ten patients achieved partial response (PR), and 36 achieved stable disease (SD), representing a response rate of 17.2% and a disease control rate of 77.6%. Median progression-free survival was 3.3 months (95% CI 1.595–5.071). The toxicities associated with anlotinib were generally acceptable with a total grade 3/4 toxicity of 5.2%. The toxicities of anlotinib were generally tolerated and the common toxicities were hand–foot syndrome and hypertension.ConclusionIn the third-line or more-line treatment of advanced lung cancer, anlotinib appears to have some activity when utilized as a salvage treatment. Adverse reactions are controllable.

Proteomic Analysis of Breast Cancer Resistance to the Anticancer Drug RH1 Reveals the Importance of Cancer Stem Cells.

Antitumor drug resistance remains a major challenge in cancer chemotherapy. Here we investigated the mechanism of acquired resistance to a novel anticancer agent RH1 designed to be activated in cancer cells by the NQO1 enzyme. Data show that in some cancer cells RH1 may act in an NQO1-independent way. Differential proteomic analysis of breast cancer cells with acquired resistance to RH1 revealed changes in cell energy, amino acid metabolism and G2/M cell cycle transition regulation. Analysis of phosphoproteomics and protein kinase activity by multiplexed kinase inhibitor beads showed an increase in the activity of protein kinases involved in the cell cycle and stemness regulation and downregulation of proapoptotic kinases such as JNK in RH1-resistant cells. Suppression of JNK leads to the increase of cancer cell resistance to RH1. Moreover, resistant cells have enhanced expression of stem cell factor (SCF) and stem cell markers. Inhibition of SCF receptor c-KIT resulted in the attenuation of cancer stem cell enrichment and decreased amounts of tumor-initiating cells. RH1-resistant cells also acquire resistance to conventional therapeutics while remaining susceptible to c-KIT-targeted therapy. Data show that RH1 can be useful to treat cancers in the NQO1-independent way, and targeting of the cancer stem cells might be an effective approach for combating resistance to RH1 therapy.

Hematopoietic stem cell transplantation gene therapy for hemophilia a using non-genotoxic ANTI-CD117 immunotoxin conditioning

Background & Aim Hematopoietic stem cell transplantation (HSCT) for coagulation factor VIII (fVIII) gene therapy is a potentially curative approach for the treatment of the most common severe bleeding disorder, hemophilia A (HA). Our laboratory has previously established the ability to produce stable therapeutic levels of fVIII in a mouse model of HA following irradiation or chemotherapy and transplantation of Sca-1+ cells, a population containing both HSC and progenitors, genetically modified ex vivo using recombinant lentiviral vector encoding a bioengineered high-expression fVIII variant, termed ET3. Conventional myeloablative regimens for HSCT such as total body irradiation and myeloablative alkylating chemotherapy are associated with adverse side effects, including sterility, hormonal dysregulation and genotoxicity. These risks represent a primary barrier to clinical translation of HSCT gene therapy for HA and many other monogenic diseases. Therefore, the development of targeted, non-genotoxic conditioning agents is critical. Methods, Results & Conclusion We have successfully implemented the use of an immunotoxin bioconjugate comprised of a monoclonal antibody against the stem cell factor receptor c-Kit (anti-CD117) and the ribosome-inactivating protein toxin saporin (sap) for non-genotoxic HSCT conditioning. We achieved consistent depletion of bone marrow LSK (lineage-negative Sca-1+ c-Kit+) and long-term HSC (LSK+ CD150+ CD48−) compartments five days after retro-orbital venous sinus injection of 0.5 mg/kg CD117-sap compared to control (59.2% LSK reduction; 38.9% LT-HSC reduction) in both C57BL/6J wild-type and HA mice. Following CD117-sap conditioning, HA mice were transplanted with 1 × 106 ET3-transduced Sca-1+ cells from GFP+ congenic mice. We observed robust mixed hematopoietic chimerism and myeloid engraftment at two and four weeks post-transplantation in recipients conditioned with CD117-sap compared to control mice (2 wk: 86.4 ± 9.2% vs. 1.2 ± 0.6% GFP+ granulocytes, p = 0.00009; 4 wk: 93.9 ± 5.6% vs. 0.2 ± 0.3% GFP+ granulocytes, p = 0.0018). Moreover, these mice exhibit therapeutic levels of circulating fVIII activity as early as 2 weeks post-transplantation (0.11 IU/ml, p = 0.005). Taken together, these preliminary data are a promising proof-of-concept demonstrating the feasibility of using non-genotoxic immunotoxin conditioning for HA gene therapy.

Famitinib in combination with concurrent chemoradiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma: a phase 1, open-label, dose-escalation Study

BackgroundFamitinib is a tyrosine kinase inhibitor against multiple targets, including vascular endothelial growth factor receptor 2/3, platelet-derived growth factor receptor, and stem cell factor receptor (c-kit). Previous studies have demonstrated anti-tumour activities of famitinib against a wide variety of advanced-stage solid cancers. We aimed to determine the safety and efficacy of famitinib with concurrent chemoradiotherapy (CCRT) in patients with locoregionally advanced nasopharyngeal carcinoma (NPC). We also evaluated the feasibility of contrast-enhanced ultrasound (D-CEUS) as a predictor of early tumour response to famitinib and to correlate functional parameters with clinical efficacy.MethodsThe trial was conducted in subjects with stage III or IVa-b NPC using a 3 + 3 design of escalating famitinib doses. Briefly, subjects received 2 weeks of famitinib monotherapy followed by 7 weeks of famitinib plus CCRT. D-CEUS of the neck lymph nodes was performed at day 0, 8 and 15 after famitinib was administered before starting concurrent chemoradiotherapy. End points included safety, tolerability and anti-tumour activity.ResultsTwenty patients were enrolled (six each for 12.5, 16.5 and 20 mg and two for 25 mg). Two patients in the 25 mg cohort developed dose-limiting toxicities, including grade 4 thrombocytopenia and grade 3 hypertension. The most common grade 3/4 adverse events were leukopenia, neutropenia and radiation mucositis. D-CEUS tests showed that more than 60% of patients achieved a perfusion parameter response after 2 weeks taking famitinib alone, and the parameter response was associated with disease improvement. In the famitinib monotherapy stage, three patients (15%) showed partial responses. The complete response rate was 65% at the completion of treatment and 95% 3 months after the treatment ended. After a median follow-up of 44 months, the 3-year progression-free survival (PFS) and distant metastasis-free survival were 70% and 75%, respectively. Subjects with a decrease of perfusion parameter response, such as peak intensity decreased at least 30% after 1 week of famitinib treatment, had higher 3-year PFS (90.9% vs. 44.4%, 95% CI 73.7%–100% vs. 11.9%–76.9%, P < 0.001) than those with an increase or a reduction of less than 30%.ConclusionsThe recommended famitinib dose for phase II trial is 20 mg with CCRT for patients with local advanced NPC. D-CEUS is a reliable and early measure of efficacy for famitinib therapies. Further investigation is required to confirm the effects of famitinib plus chemoradiotherapy.