Stem Cell Factor Gene Research Articles

BSBM-15 SYSTEMIC AND LOCAL IMMUNE RESPONSES FOLLOWING STEREOTACTIC RADIOSURGERY TO BRAIN METASTASES FROM HER2-AMPLIFIED BREAST CANCER

Abstract BACKGROUND Brain metastases (BMs) afflict 30-50% of HER2-amplified breast cancer (HER2-BC) patients. Stereotactic radiosurgery (SRS) is a highly effective focal treatment for BMs. Extracranial radiotherapy can promote anti-tumor immune responses that synergize with immunotherapy, but whether this applies to the brain microenvironment remains unclear. Here, we examined blood and BM samples from HER2-BC patients in the TROG 16.02 translational sub-study for immunological effects of SRS (ACTRN12616001265460). METHODS Blood samples from 10 patients taken pre- and 7-14 days post-SRS to intact HER2-BC BMs or post-resection BM cavities were analyzed by mass and flow cytometry for immune cell and cytokine modulation. One patient received pre-operative SRS for a BM that recurred 6 months after resection, followed by re-resection of the BM 7 days post-SRS. Tumors from pre- and post-SRS timepoints in this patient were analyzed by bulk RNAseq and immunohistochemistry. RESULTS Monocytes, CD8+ T effector memory and regulatory T cells were enriched in blood post-SRS, while conventional dendritic cells, CD4+ T early and CD4+ TEMRA cells were diminished. Stem cell factor (SCF) concentration, a growth factor important for monocyte production, was elevated in plasma post-SRS. In the tumor, SRS upregulated gene signatures for monocyte/macrophage processes (including SCF gene transcript levels), antigen presentation, and T cell activation. Cell type deconvolution from RNAseq suggested an SRS-induced loss of metastatic tumor cells and enrichment of macrophages and CD4+ T cells. Immunohistochemistry corroborated the influx of CD68+ macrophages and CD3+ T cells into tumor and brain regions post-SRS, with spatial co-localization evident between the cell types. Furthermore, the pre-SRS immune-excluded phenotype in tumor regions was no longer observed post-SRS. CONCLUSION Systemic and local immunological changes in this homogenous patient cohort receiving SRS to HER2-BC BMs suggest a radiation-induced adaptive immune response intracranially, involving the monocyte-macrophage lineage as antigen presenting cells, that should be further explored.

LncRNA Osilr9 coordinates promoter DNA demethylation and the intrachromosomal loop structure required for maintaining stem cell pluripotency

Nuclear reprogramming of somatic cells into a pluripotent status has the potential to create patient-specific induced pluripotent stem cells for regenerative medicine. Currently, however, the epigenetic mechanisms underlying this pluripotent reprogramming are poorly understood. To delineate this epigenetic regulatory network, we utilized a chromatin RNA in situ reverse transcription sequencing (CRIST-seq) approach to identify long noncoding RNAs (lncRNAs) embedded in the 3-dimensional intrachromosomal architecture of stem cell core factor genes. By combining CRIST-seq and RNA sequencing, we identified Oct4-Sox2 interacting lncRNA 9 (Osilr9) as a pluripotency-associated lncRNA. Osilr9 expression was associated with the status of stem cell pluripotency in reprogramming. Using short hairpin RNA (shRNA) knockdown, we showed that this lncRNA was required for the optimal maintenance of stem cell pluripotency. Overexpression of Osilr9 induced robust activation of endogenous stem cell core factor genes in fibroblasts. Osilr9 participated in the formation of the intrachromosomal looping required for the maintenance of pluripotency. After binding to the Oct4 promoter, Osilr9 recruited the DNA demethylase ten-eleven translocation 1, leading to promoter demethylation. These data demonstrate that Osilr9 is a critical chromatin epigenetic modulator that coordinates the promoter activity of core stem cell factor genes, highlighting the critical role of pluripotency-associated lncRNAs in stem cell pluripotency and reprogramming.

Polycomb proteins control floral determinacy by H3K27me3-mediated repression of pluripotency genes in Arabidopsis thaliana.

Polycomb group (PcG) protein-mediated histone methylation (H3K27me3) controls the correct spatiotemporal expression of numerous developmental regulators in Arabidopsis. Epigenetic silencing of the stem cell factor gene WUSCHEL (WUS) in floral meristems (FMs) depends on H3K27me3 deposition by PcG proteins. However, the role of H3K27me3 in silencing of other meristematic regulator and pluripotency genes during FM determinacy has not yet been studied. To this end, we report the genome-wide dynamics of H3K27me3 levels during FM arrest and the consequences of strongly depleted PcG activity on early flower morphogenesis including enlarged and indeterminate FMs. Strong depletion of H3K27me3 levels results in misexpression of the FM identity gene AGL24, which partially causes floral reversion leading to ap1-like flowers and indeterminate FMs ectopically expressing WUS and SHOOT MERISTEMLESS (STM). Loss of STM can rescue supernumerary floral organs and FM indeterminacy in H3K27me3-deficient flowers, indicating that the hyperactivity of the FMs is at least partially a result of ectopic STM expression. Nonetheless, WUS remained essential for the FM activity. Our results demonstrate that PcG proteins promote FM determinacy at multiple levels of the floral gene regulatory network, silencing initially floral regulators such as AGL24 that promotes FM indeterminacy and, subsequently, meristematic pluripotency genes such as WUS and STM during FM arrest.

Therapeutic effect of Cistanche deserticola on defecation in senile constipation rat model through stem cell factor/C-kit signaling pathway.

BACKGROUNDConstipation is one of the chronic gastrointestinal functional diseases. It seriously affects the quality of life. Cistanche deserticola (C. deserticola) can treat constipation obviously, but its mechanism has not been clarified. We supposed that mechanism of it improved the intestinal motility by stimulating interstitial Cajal cells (ICC). Activation of the C-kit receptor on the surface of ICC is closely related to ICC function, and the stem cell factor (SCF)/C-kit signaling pathways plays an important role on it. To investigate the mechanism of how C. deserticola treats constipation, this study aimed to establish a constipation model in rats and explore the role of SCF/C-kit signaling pathway in the treatment. AIMTo explore the SCF/C-kit signaling pathways in the role of C. deserticola for treatment of constipation by a constipation rat model.METHODSForty-eight 8-mo-old Sprague–Dawley rats were divided into 4 groups by random weight method: Normal group (n = 12), model group (n = 12), C. deserticola group (n = 12) and blocker group (n = 12). The normal group received normal saline by gavage; the model group received loperamide by gavage; the blocker group received loperamide and C. deserticola by gavage, and STI571 was injected by intraperitoneally. During treatment, the weight, fecal granules and fecal quality were recorded every 10 d. On day 20 after model induction, the colon tissues of each group were removed. Hematoxylin and eosin staining was used to observe pathological changes. Expression levels of SCF, C-kit and Aquaporin genes were detected by immunohistochemistry, western blotting, and real-time-quantitative polymerase chain reaction. The colonic epithelial mitochondria and goblet cells were observed by transmission electron microscopy.RESULTSCompared with the normal group, as treatment progressed, the weight of rats in the model and blocker groups decreased significantly, the stool weight decreased, and the stool quality was dry (P < 0.05). C. deserticola reversed the decrease in body weight and stool weight and improved stool quality. Histopathological analysis indicated that the colonic mucosal epithelium in the model group was incomplete, and the arrangement of the glands was irregular or damaged. Treatment with C. deserticola improved the integrity and continuity of the epithelial cells and regular arrangement of the glands. The blocking agents inhibited the effects of C. deserticola Immunohistochemistry and real-time-quantitative polymerase chain reaction showed that expression of SCF and C-kit protein or genes in the colonic tissue of the model group was decreased (P < 0.05), while treatment with C. deserticola increased protein or gene expression (P < 0.05). Western blotting showed that expression of aquaporin APQ3 was increased, while the expression of Cx43 decreased in the model group. Treatment with C. deserticola inhibited expression of APQ3 and promoted expression of Cx43. Transmission electron microscopy showed that the mitochondria of the colonic epithelium in the model group were swollen and arranged disorderly, and microvilli were sparse. The condition was better in the C. deserticola group. Mice treated with STI571 blocker confirmed that blocking the SCF/C-kit pathway inhibited the improvement of constipation by C. deserticola.CONCLUSIONC. deserticola improved defecation in rats with constipation, and the SCF/C-kit signaling pathway, which is a key link of ICC function, played an important role of the treatment.

Chromatin lncRNA Platr10 controls stem cell pluripotency by coordinating an intrachromosomal regulatory network

BackgroundA specific 3-dimensional intrachromosomal architecture of core stem cell factor genes is required to reprogram a somatic cell into pluripotency. As little is known about the epigenetic readers that orchestrate this architectural remodeling, we used a novel chromatin RNA in situ reverse transcription sequencing (CRIST-seq) approach to profile long noncoding RNAs (lncRNAs) in the Oct4 promoter.ResultsWe identify Platr10 as an Oct4 - Sox2 binding lncRNA that is activated in somatic cell reprogramming. Platr10 is essential for the maintenance of pluripotency, and lack of this lncRNA causes stem cells to exit from pluripotency. In fibroblasts, ectopically expressed Platr10 functions in trans to activate core stem cell factor genes and enhance pluripotent reprogramming. Using RNA reverse transcription-associated trap sequencing (RAT-seq), we show that Platr10 interacts with multiple pluripotency-associated genes, including Oct4, Sox2, Klf4, and c-Myc, which have been extensively used to reprogram somatic cells. Mechanistically, we demonstrate that Platr10 helps orchestrate intrachromosomal promoter-enhancer looping and recruits TET1, the enzyme that actively induces DNA demethylation for the initiation of pluripotency. We further show that Platr10 contains an Oct4 binding element that interacts with the Oct4 promoter and a TET1-binding element that recruits TET1. Mutation of either of these two elements abolishes Platr10 activity.ConclusionThese data suggest that Platr10 functions as a novel chromatin RNA molecule to control pluripotency in trans by modulating chromatin architecture and regulating DNA methylation in the core stem cell factor network.

Stem Cell Factor Gene Overexpression Enhances the Fusion Potential of Rat Bone Marrow Mesenchymal Stem Cells with Cardiomyocytes

Stem Cell Factor Gene Overexpression Enhances the Fusion Potential of Rat Bone Marrow Mesenchymal Stem Cells with Cardiomyocytes

Anti-Müllerian Hormone Regulates Stem Cell Factor via cAMP/PKA Signaling Pathway in Human Granulosa Cells by Inhibiting the Phosphorylation of CREB.

Anti-Müllerian hormone (AMH) downregulates the level of stem cell factor (SCF) via the cAMP/PKA signaling pathway in human granulosa cells (GCs). Little information is available on the molecular mechanism underlying the interaction. This study is aimed at determining whether AMH regulates expression of SCF via the cAMP-PKA-CREB signaling pathway in human GCs. In the present study, we verified the binding of cAMP-response element-binding protein (CREB) to promoter of SCF in human GCs. Furthermore, the effect of CREB was tested on the SCF promoter, and the site of CREB binding to SCF promoter was identified using truncations as well as assays of SCF-promoted mutation and CREB mutation. To investigate the correlation among AMH, SCF promoter, and CREB, pGL-Basic-SCF+CREB was transfected into overexpressed AMH GCs (AMH-high GCs), low expressed AMH GCs (AMH-low GCs), and normal GCs (GCs), respectively. Finally, immunofluorescence, double immunostaining, and Western blot were carried out in AMH-high and AMH-low GCs to confirm the AMH-mediated regulation of SCF expression by inhibiting the phosphorylation of CREB (pCREB) in GCs. Results indicated CREB interacted with SCF promoter and significantly enhanced the transcription level of SCF. The CREB binding site was localized at 318-321bp of SCF gene promote. AMH inhibits the expression of SCF by phosphorylation of CREB via the PKA signaling pathway in GCs. These findings provide an in-depth understanding of the molecular mechanism underlying AMH suppressing the follicle growth, which would aid in the development of a novel therapy.

Profiling the long noncoding RNA interaction network in the regulatory elements of target genes by chromatin in situ reverse transcription sequencing.

Long noncoding RNAs (lncRNAs) can regulate the activity of target genes by participating in the organization of chromatin architecture. We have devised a “chromatin-RNA in situ reverse transcription sequencing” (CRIST-seq) approach to profile the lncRNA interaction network in gene regulatory elements by combining the simplicity of RNA biotin labeling with the specificity of the CRISPR/Cas9 system. Using gene-specific gRNAs, we describe a pluripotency-specific lncRNA interacting network in the promoters of Sox2 and Pou5f1, two critical stem cell factors that are required for the maintenance of pluripotency. The promoter-interacting lncRNAs were specifically activated during reprogramming into pluripotency. Knockdown of these lncRNAs caused the stem cells to exit from pluripotency. In contrast, overexpression of the pluripotency-associated lncRNA activated the promoters of core stem cell factor genes and enhanced fibroblast reprogramming into pluripotency. These CRIST-seq data suggest that the Sox2 and Pou5f1 promoters are organized within a unique lncRNA interaction network that determines the fate of pluripotency during reprogramming. This CRIST approach may be broadly used to map lncRNA interaction networks at target loci across the genome.

Lactobacillus Plantarum CQPC05 Isolated from Pickled Vegetables Inhibits Constipation in Mice

This study mainly investigated the influences of Lactobacillus plantarum CQPC05 (CQPC05) isolated from pickled vegetables on mouse constipation caused by activated carbon water. We used 16S rDNA technology to identify the microorganism, and activated carbon to establish a mouse constipation model. After the mice received L. plantarum (109 CFU/mL) by gavage, small intestine tissue sections were collected. The serum indices and small intestine-related mRNA expression were obtained. A strain of L. plantarum was identified, and named CQPC05. The body weight and activated carbon progradation rate in the mice of the CQPC05 treatment groups were significantly higher than those in the control group, and the excretion time of the first tarry stool was earlier than that of the control group. The results of serum indices indicated that serum gastrin (Gas), endothelin (ET), and acetylcholinesterase (AchE) levels in the CQPC05 treatment groups were significantly higher than those in the control group, while the somatostatin (SS) level was significantly lower. Compared to the constipation control group, the result of q-PCR demonstrated that CQPC05 could up-regulate the mRNA expression of c-Kit (stem cell factor receptor), SCF (stem cell factor), and GDNF (glial cell-derived neurotrophic factor) genes, and down-regulate the expression of TRPV1 (transient receptor potential cation channel subfamily V member 1) and iNOS (inducible nitric oxide synthase). In conclusion, L. plantarum CQPC05 can effectively alleviate constipation, and has good probiotic potential and application value.

Silencing Stem Cell Factor Gene in Fibroblasts to Regulate Paracrine Factor Productions and Enhance c-Kit Expression in Melanocytes on Melanogenesis.

Melanogenesis is a complex physiological mechanism involving various paracrine factors. Skin cells such as keratinocytes, fibroblasts, and melanocytes communicate with one another through secreted regulators, thereby regulating the melanocytes’ bio-functions. The stem cell factor (SCF) is a paracrine factor produced by fibroblasts, and its receptor, c-kit, is expressed on melanocytes. Binding of SCF to c-kit activates autophosphorylation and tyrosine kinase to switch on its signal transmission. SCF inhibition does not suppress fibroblast proliferation in MTT assay, and SCF silencing induced mRNA expressions of paracrine factor genes, HGF, NRG-1, and CRH in qPCR results. Following UVB stimulation, gene expressions of HGF, NRG, and CRH were higher than homeostasis; in particular, HGF exhibited the highest correlation with SCF variations. We detected fibroblasts regulated SCF in an autocrine-dependent manner, and the conditioned medium obtained from fibroblast culture was applied to treat melanocytes. Melanogenesis-related genes, tyrosinase and pmel17, were upregulated under conditioned mediums with SCF silencing and exposed to UVB treatments. Melanin quantities in the melanocytes had clearly increased in the pigment content assay. In conclusion, SCF silencing causes variations in both fibroblast paracrine factors and melanocyte melanogenesis, and the differences in gene expressions were observed following UVB exposure.

MP81-15 PROSTATE SMALL CELL CARCINOMA EXPRESS STEM CELL FACTORS THAT CAN TRANSFORM NORMAL AND CANCER CELLS INTO STEM-LIKE

You have accessJournal of UrologyStem Cell Research: Stem Cell Research II1 Apr 2018MP81-15 PROSTATE SMALL CELL CARCINOMA EXPRESS STEM CELL FACTORS THAT CAN TRANSFORM NORMAL AND CANCER CELLS INTO STEM-LIKE Adelle Kanan and Alvin Liu Adelle KananAdelle Kanan More articles by this author and Alvin LiuAlvin Liu More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2723AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Prostate cancer can be grouped into either luminal-like (differentiated) or stem-like (undifferentiated). The latter type includes small cell carcinoma. The LuCaP 145.1 small cell carcinoma xenograft line shows expression of stem cell transcription factors LIN28A, NANOG, POU5F1 and SOX2. Luminal-like adenocarcinoma LuCaP lines show expression of only one or two of these factors, while cancer cells of Gleason patterns 3 and 4 do not. Forced expression of these four genes in differentiated somatic cells produces induced pluripotent stem (iPS) cells. We want to determine if other LuCaP small cell carcinoma xenografts also express these genes, and whether these genes cloned from LuCaP 145.1 can also transform cell types, both normal and cancer, into stem-like. METHODS LuCaP small cell carcinoma harvested from mice were minced and digested by collagenase. The resultant cells were centrifuged on Percoll density gradients. Gene expression was analyzed by RT-PCR. Full-length LIN28A, NANOG, POU5F1 and SOX2 cDNA (Kozak box, ATG start to stop codon) were cloned from LuCaP 145.1 into mammalian expression vector pVITRO1-neo, and transfected by electroporation into HEK293F fibroblasts and luminal-like prostate cancer cells LNCaP and C4-2B. Individual colonies under drug G418 selection (1 mg/ml) were cloned, and analyzed for gene expression. Transfected cells were grown 1) in media supplemented with 10% fetal bovine serum under normoxia, 2) in serum-free media with KnockOut Serum Replacement, 3) on Matrigel-coated plates, 4) on irradiated mouse embryonic fibroblasts (MEF) under hypoxia. RESULTS The four stem cell factor genes were expressed by all established LuCaP small cell carcinoma examined: LuCaP 93, 145.1, 145.2, 173.1, 173.2A. LuCaP 145.1 cells also showed a stromal cell density (1.035). Transfection of plasmid pLP2 containing LIN28A/POU5F1 and pSN4 containing SOX2/NANOG into HEK293F, LNCaP and C4-2 produced cells displaying a stem cell-like colony morphology. Neo (G418)-resistant cells appeared in ~ 1 week, and showed expression of the stem cell factor genes as well as low expression of B2M (β 2-microglobulin) a characteristic of stem cells. The colony morphology was distinct from that of the untransfected cells, and showed differences among the culture conditions used. CONCLUSIONS Transcription factors cloned from small cell carcinoma are capable of transforming normal and cancer cells. The generated plasmid vectors are safer to use than lentiviral vectors; G418 allows selection of transfected cells, and deters microbial contamination. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e1102 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Adelle Kanan More articles by this author Alvin Liu More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Comparative genomics of human stem cell factor (SCF).

Stem cell factor (SCF) is a critical protein with key roles in the cell such as hematopoiesis, gametogenesis and melanogenesis. In the present study a comparative analysis on nucleotide sequences of SCF was performed in Humanoids using bioinformatics tools including NCBI-BLAST, MEGA6, and JBrowse. Our analysis of nucleotide sequences to find closely evolved organisms with high similarity by NCBI-BLAST tools and MEGA6 showed that human and Chimpanzee (Pan troglodytes) were placed into the same cluster. By using JBrowse, we found that SCF in Neanderthal had a single copy number similar to modern human and partly conserved nucleotide sequences. Together, the results approved the gene flow and genetics similarity of SCF among human and P. troglodytes. This may suggest that during evolution, SCF gene transferred partly intact either on the basis of sequence or function from the same ancestors to P. troglodytes, the ancient human like Neanderthal, and then to the modern human.

HIF-2-dependent expression of stem cell factor promotes metastasis in hepatocellular carcinoma

Stem cell factor (SCF) is a multifunctional cytokine responsible for tumorigenesis and progression. In this study, we report that increased expression of SCF in hepatocellular carcinoma (HCC) patients is highly associated with metastasis and poor prognosis. SCF inhibition with RNAi inhibited HCC cell migration, invasion in vitro, and reduced intrahepatic metastases burden and significantly prolonged survival in a HCC xeograft mouse model. SCF depletion in HCC xeograft decreased the expression of vimentin and increase the expression of E-cadherin, implicating a role for SCF in epithelial–mesenchymal transition. Our data further demonstrated that HCC cells secreted soluble SCF to promote HUVECs angiogenesis. The overexpression of SCF in HCC is regulated by hypoxic conditions through a selective HIF-2α-dependent mechanism. Knocking-down HIF-2α significantly decreased expression of SCF. Chromatin immunoprecipitation and luciferase assay demonstrated that HIF-2α directly induce the transcription of SCF gene through the hypoxia response element in SCF promoter. In conclusion, we demonstrate that the hypoxia microenvironment in HCC up-regulates SCF expression, which in turn promotes angiogenesis and HCC metastasis.

Association of stem cell factor gene expression with severity and atopic state in patients with bronchial asthma

Background Bronchial asthma is a chronic inflammatory and remodeling disorder of the airways, in which many cells, cellular elements, and cytokines play important roles. Stem cell factor (SCF) may contribute to the inflammatory changes occurring in asthma. We aimed to show the expression of SCF gene in patients with asthma as a means of diagnosis and its association with severity and atopic state in these patients.MethodsThis study was carried out on 80 subjects, 50 asthmatic patients and 30 age and gender matched healthy control persons. They were subjected to full history taking, general and local chest examination, spirometric measurements (pre and post broncodilators) using a spirometer, serum IgE, and real time PCR for assessment of SCF mRNA expression.ResultsThis study showed significant difference between the studied groups regarding pulmonary function tests (P < 0.001). Asthmatic patients had significant higher SCF expression compared to control (P < 0.001), also atopic patients vs non atopic (P = 0.03) and severe asthmatic patients vs mild ones (P < 0.001). SCF expression at cut off point (0.528) is sufficient to discriminate asthmatic patients from control while at cut off point (1.84) for discrimination of atopic patients from non-atopic patients and at cut off point (1.395) for discrimination of severe asthmatic patients from mild ones. A significant negative correlation between SCF expression and inhaled steroid while significant positive correlation with serum IgE was found.ConclusionMeasuring SCF mRNA expression can be used as an efficient marker for evaluation of atopy and detection of severity of bronchial asthma.

In Silico comparative protein analysis of Human Stem Cell factor (SCF)

In Silico comparative protein analysis of Human Stem Cell factor (SCF) Stem cell factor (SCF) is a critical protein with several key roles in the cell such as hematopoiesis, gametogenesis and melanogenesis. In the present study, the in silico analysis including phylogenetics, protein network analysis (interactome) and conservation assessment on SCF was performed using NCBIBLAST, MEGA6 software, STRING 10 database and ClustalX 2.1 software. Analysis of the shared SCF protein interactors in human (Homo sapiens), Gorilla (Gorilla gorilla) and Chimpanzee (Pan troglodytes) demonstrated the presence of partly either conserved proteins interactors or proteins with the same function. Moreover, the data showed that 152 amino acids of SCF were conserved among the examined primates. Together, the results approved the gene flow and genetics similarity of SCF among human, Gorilla and Chimpanzee. This may suggest that during evolution, SCF gene transferred partly intact either on the basis of protein sequence or function from the same ancestors to Gorilla, Chimpanzee and human.

Stem cell factor gene transfer improves cardiac function after myocardial infarction in swine.

Stem cell factor (SCF), a ligand of the c-kit receptor, is a critical cytokine, which contributes to cell migration, proliferation, and survival. It has been shown that SCF expression increases after myocardial infarction (MI) and may be involved in cardiac repair. The aim of this study was to determine whether gene transfer of membrane-bound human SCF improves cardiac function in a large animal model of MI. A transmural MI was created by implanting an embolic coil in the left anterior descending artery in Yorkshire pigs. One week after the MI, the pigs received direct intramyocardial injections of either a recombinant adenovirus encoding for SCF (Ad.SCF, n=9) or β-gal (Ad.β-gal, n=6) into the infarct border area. At 3 months post-MI, ejection fraction increased by 12% relative to baseline after Ad.SCF therapy, whereas it decreased by 4.2% (P=0.004) in pigs treated with Ad.β-gal. Preload-recruitable stroke work was significantly higher in pigs after SCF treatment (Ad.SCF, 55.5±11.6 mm Hg versus Ad.β-gal, 31.6±12.6 mm Hg, P=0.005), indicating enhanced cardiac function. Histological analyses confirmed the recruitment of c-kit(+) cells as well as a reduced degree of apoptosis 1 week after Ad.SCF injection. In addition, increased capillary density compared with pigs treated with Ad.β-gal was found at 3 months and suggests an angiogenic role of SCF. Local overexpression of SCF post-MI induces the recruitment of c-kit(+) cells at the infarct border area acutely. In the chronic stages, SCF gene transfer was associated with improved cardiac function in a preclinical model of ischemic cardiomyopathy.

Anti-KIT designer T cells for the treatment of gastrointestinal stromal tumor

BackgroundImatinib mesylate is an effective treatment for metastatic gastrointestinal stromal tumor (GIST). However, most patients eventually develop resistance and there are few other treatment options. Immunotherapy using genetically modified or designer T cells (dTc) has gained increased attention for several malignancies in recent years. The aims of this study were to develop and test novel anti-KIT dTc engineered to target GIST cells.MethodsHuman anti-KIT dTc were created by retroviral transduction with novel chimeric immune receptors (CIR). The gene for stem cell factor (SCF), the natural ligand for KIT, was cloned into 1st generation (SCF-CD3ζ, 1st gen) and 2nd generation (SCF-CD28-CD3ζ, 2nd gen) CIR constructs. In vitro dTc proliferation and tumoricidal capacity in the presence of KIT+ tumor cells were measured. In vivo assessment of dTc anti-tumor efficacy was performed by treating immunodeficient mice harboring subcutaneous GIST xenografts with dTc tail vein infusions.ResultsWe successfully produced the 1st and 2nd gen anti-KIT CIR and transduced murine and human T cells. Average transduction efficiencies for human 1st and 2nd gen dTc were 50% and 42%. When co-cultured with KIT+ tumor cells, both 1st and 2nd gen dTc proliferated and produced IFNγ. Human anti-KIT dTc were efficient at lysing GIST in vitro compared to untransduced T cells. In mice with established GIST xenografts, treatment with either 1st or 2nd gen human anti-KIT dTc led to significant reductions in tumor growth rates.ConclusionsWe have constructed a novel anti-KIT CIR for production of dTc that possess specific activity against KIT+ GIST in vitro and in vivo. Further studies are warranted to evaluate the therapeutic potential and safety of anti-KIT dTc.

The 10 Most Read Articles Published in Circulation Research in 2012

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Stem Cell Factor Gene Transfer Promotes Cardiac Repair After Myocardial Infarction via In Situ Recruitment and Expansion of c-kit + Cells

There is growing evidence that the myocardium responds to injury by recruiting c-kit(+) cardiac progenitor cells to the damage tissue. Even though the ability of exogenously introducing c-kit(+) cells to injured myocardium has been established, the capability of recruiting these cells through modulation of local signaling pathways by gene transfer has not been tested. To determine whether stem cell factor gene transfer mediates cardiac regeneration in a rat myocardial infarction model, through survival and recruitment of c-kit(+) progenitors and cell-cycle activation in cardiomyocytes, and explore the mechanisms involved. Infarct size, cardiac function, cardiac progenitor cells recruitment, fibrosis, and cardiomyocyte cell-cycle activation were measured at different time points in controls (n=10) and upon stem cell factor gene transfer (n=13) after myocardial infarction. We found a regenerative response because of stem cell factor overexpression characterized by an enhancement in cardiac hemodynamic function: an improvement in survival; a reduction in fibrosis, infarct size and apoptosis; an increase in cardiac c-kit(+) progenitor cells recruitment to the injured area; an increase in cardiomyocyte cell-cycle activation; and Wnt/β-catenin pathway induction. Stem cell factor gene transfer induces c-kit(+) stem/progenitor cell expansion in situ and cardiomyocyte proliferation, which may represent a new therapeutic strategy to reverse adverse remodeling after myocardial infarction.

Skipping of exons by premature termination of transcription and alternative splicing within intron-5 of the sheep SCF gene: a novel splice variant.

Stem cell factor (SCF) is a growth factor, essential for haemopoiesis, mast cell development and melanogenesis. In the hematopoietic microenvironment (HM), SCF is produced either as a membrane-bound (−) or soluble (+) forms. Skin expression of SCF stimulates melanocyte migration, proliferation, differentiation, and survival. We report for the first time, a novel mRNA splice variant of SCF from the skin of white merino sheep via cloning and sequencing. Reverse transcriptase (RT)-PCR and molecular prediction revealed two different cDNA products of SCF. Full-length cDNA libraries were enriched by the method of rapid amplification of cDNA ends (RACE-PCR). Nucleotide sequencing and molecular prediction revealed that the primary 1519 base pair (bp) cDNA encodes a precursor protein of 274 amino acids (aa), commonly known as ‘soluble’ isoform. In contrast, the shorter (835 and/or 725 bp) cDNA was found to be a ‘novel’ mRNA splice variant. It contains an open reading frame (ORF) corresponding to a truncated protein of 181 aa (vs 245 aa) with an unique C-terminus lacking the primary proteolytic segment (28 aa) right after the D175G site which is necessary to produce ‘soluble’ form of SCF. This alternative splice (AS) variant was explained by the complete nucleotide sequencing of splice junction covering exon 5-intron (5)-exon 6 (948 bp) with a premature termination codon (PTC) whereby exons 6 to 9/10 are skipped (Cassette Exon, CE 6–9/10). We also demonstrated that the Northern blot analysis at transcript level is mediated via an intron-5 splicing event. Our data refine the structure of SCF gene; clarify the presence (+) and/or absence (−) of primary proteolytic-cleavage site specific SCF splice variants. This work provides a basis for understanding the functional role and regulation of SCF in hair follicle melanogenesis in sheep beyond what was known in mice, humans and other mammals.