RESUMO
Most secreted growth factors and cytokines are functionally pleiotropic because their receptors are expressed on diverse cell types. While important for normal mammalian physiology, pleiotropy limits the efficacy of cytokines and growth factors as therapeutics. Stem cell factor (SCF) is a growth factor that acts through the c-Kit receptor tyrosine kinase to elicit hematopoietic progenitor expansion but can be toxic when administered in vivo because it concurrently activates mast cells. We engineered a mechanism-based SCF partial agonist that impaired c-Kit dimerization, truncating downstream signaling amplitude. This SCF variant elicited biased activation of hematopoietic progenitors over mast cells in vitro and in vivo. Mouse models of SCF-mediated anaphylaxis, radioprotection, and hematopoietic expansion revealed that this SCF partial agonist retained therapeutic efficacy while exhibiting virtually no anaphylactic off-target effects. The approach of biasing cell activation by tuning signaling thresholds and outputs has applications to many dimeric receptor-ligand systems.
Assuntos
Anafilaxia/metabolismo , Células-Tronco Hematopoéticas/imunologia , Mastócitos/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais , Fator de Células-Tronco/metabolismo , Anafilaxia/imunologia , Animais , Dimerização , Humanos , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Engenharia de Proteínas , Proteínas Proto-Oncogênicas c-kit/agonistas , Proteínas Proto-Oncogênicas c-kit/química , Fator de Células-Tronco/química , Fator de Células-Tronco/genéticaRESUMO
c-Kit is a classic proto-oncogene either mutated or upregulated in cancer cells, and this leads to its constitutive kinase activation and, thus, to uncontrolled proliferation. Although the pro-oncogenic role of c-Kit is of no doubt, some observations do not fit well with c-Kit solely as a tumor-promoting moiety. We show here that c-Kit actively triggers cell death in various cancer cell lines unless engaged by its ligand stem cell factor (SCF). This pro-death activity is enhanced when the kinase activation of c-Kit is silenced and is due to c-Kit intracellular cleavage by caspase-like protease at D816. Moreover, in vivo, overexpression of a c-Kit kinase-dead mutant inhibits tumor growth, and this intrinsic c-Kit tumor-suppressive activity is dependent on the D816 cleavage. Thus, c-Kit acts both as a proto-oncogene via its kinase activity and as a tumor suppressor via its dependence receptor activity.
Assuntos
Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/fisiologia , Animais , Apoptose , Divisão Celular , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos SCID , Fosforilação , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Proto-Oncogenes , Fator de Células-Tronco/metabolismoRESUMO
Smooth muscle cells (SMCs), Interstitial cells of Cajal (ICC) and Platelet-derived growth factor receptor α positive (PDGFRα+) cells form an integrated, electrical syncytium within the gastrointestinal (GI) muscular tissues known as the SIP syncytium. Immunohistochemical analysis of gastric corpus muscles showed that c-KIT+/ANO1+ ICC-IM and PDGFRα+ cells were closely apposed to one another in the same anatomical niches. We used intracellular microelectrode recording from corpus muscle bundles to characterize the roles of intramuscular ICC and PDGFRα+ cells in conditioning membrane potentials of gastric muscles. In muscle bundles, that have a relatively higher input impedance than larger muscle strips or sheets, we recorded an ongoing discharge of stochastic fluctuations in membrane potential, previously called unitary potentials or spontaneous transient depolarizations (STDs) and spontaneous transient hyperpolarizations (STHs). We reasoned that STDs should be blocked by antagonists of ANO1, the signature conductance of ICC. Activation of ANO1 has been shown to generate spontaneous transient inward currents (STICs), which are the basis for STDs. Ani9 reduced membrane noise and caused hyperpolarization, but this agent did not block the fluctuations in membrane potential quantitatively. Apamin, an antagonist of small conductance Ca2+-activated K+ channels (SK3), the signature conductance in PDGFRα+ cells, further reduced membrane noise and caused depolarization. Reversing the order of channel antagonists reversed the sequence of depolarization and hyperpolarization. These experiments show that the ongoing discharge of STDs and STHs by ICC and PDGFRα+ cells, respectively, exerts conditioning effects on membrane potentials in the SIP syncytium that would effectively regulate the excitability of SMCs.
Assuntos
Células Gigantes , Células Intersticiais de Cajal , Potenciais da Membrana , Receptor alfa de Fator de Crescimento Derivado de Plaquetas , Animais , Células Intersticiais de Cajal/fisiologia , Células Intersticiais de Cajal/metabolismo , Camundongos , Potenciais da Membrana/fisiologia , Células Gigantes/metabolismo , Células Gigantes/fisiologia , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Anoctamina-1/metabolismo , Estômago/fisiologia , Estômago/citologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/fisiologia , Proteínas Proto-Oncogênicas c-kit/metabolismo , Masculino , Camundongos Endogâmicos C57BLRESUMO
Acute myeloid leukemia (AML) is the most common and aggressive form of acute leukemia, with a 5-year survival rate of just 24%. Over a third of all AML patients harbor activating mutations in kinases, such as the receptor tyrosine kinases FLT3 (receptor-type tyrosine-protein kinase FLT3) and KIT (mast/stem cell growth factor receptor kit). FLT3 and KIT mutations are associated with poor clinical outcomes and lower remission rates in response to standard-of-care chemotherapy. We have recently identified that the core kinase of the non-homologous end joining DNA repair pathway, DNA-PK (DNA-dependent protein kinase), is activated downstream of FLT3; and targeting DNA-PK sensitized FLT3-mutant AML cells to standard-of-care therapies. Herein, we investigated DNA-PK as a possible therapeutic vulnerability in KIT mutant AML, using isogenic FDC-P1 mouse myeloid progenitor cell lines transduced with oncogenic mutant KIT (V560G and D816V) or vector control. Targeted quantitative phosphoproteomic profiling identified phosphorylation of DNA-PK in the T2599/T2605/S2608/S2610 cluster in KIT mutant cells, indicative of DNA-PK activation. Accordingly, proliferation assays revealed that KIT mutant FDC-P1 cells were more sensitive to the DNA-PK inhibitors M3814 or NU7441, compared with empty vector controls. DNA-PK inhibition combined with inhibition of KIT signaling using the kinase inhibitors dasatinib or ibrutinib, or the protein phosphatase 2A activators FTY720 or AAL(S), led to synergistic cell death. Global phosphoproteomic analysis of KIT-D816V cells revealed that dasatinib and M3814 single-agent treatments inhibited extracellular signal-regulated kinase and AKT (RAC-alpha serine/threonine-protein kinase)/MTOR (serine/threonine-protein kinase mTOR) activity, with greater inhibition of both pathways when used in combination. Combined dasatinib and M3814 treatment also synergistically inhibited phosphorylation of the transcriptional regulators MYC and MYB. This study provides insight into the oncogenic pathways regulated by DNA-PK beyond its canonical role in DNA repair and demonstrates that DNA-PK is a promising therapeutic target for KIT mutant cancers.
Assuntos
Proteína Quinase Ativada por DNA , Leucemia Mieloide Aguda , Animais , Camundongos , Apoptose , Linhagem Celular Tumoral , Dasatinibe , DNA , Proteína Quinase Ativada por DNA/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/tratamento farmacológico , Mutação , Inibidores de Proteínas Quinases/farmacologia , Receptores Proteína Tirosina Quinases , Serina , Transdução de Sinais , Treonina , Serina-Treonina Quinases TOR , TirosinaRESUMO
Targeting the FLT3 receptor and the IL-1R associated kinase 4 as well as the anti-apoptotic proteins MCL1 and BCL2 may be a promising novel approach in the treatment of acute myeloid leukemia (AML). The FLT3 and IRAK4 inhibitor emavusertib (CA4948), the MCL1 inhibitor S63845, the BCL2 inhibitor venetoclax, and the HSP90 inhibitor PU-H71 were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells in vitro. AML cells represented all major morphologic and molecular subtypes, including FLT3-ITD and NPM1 mutant AML cell lines and a variety of patient-derived AML cells. Emavusertib in combination with MCL1 inhibitor S63845 or BCL2 inhibitor venetoclax induced cell cycle arrest and apoptosis in MOLM-13 cells. In primary AML cells, the response to emavusertib was associated with the presence of the FLT3 gene mutation with an allelic ratio >0.5 and the presence of NPM1 gene mutations. S63845 was effective in all tested AML cell lines and primary AML samples. Blast cell percentage was positively associated with the response to CA4948, S63845, and venetoclax, with elevated susceptibility of primary AML with blast cell fraction >80%. Biomarkers of the response to venetoclax included the blast cell percentage and bone marrow infiltration rate, as well as the expression levels of CD11b, CD64, and CD117. Elevated susceptibility to CA4948 combination treatments with S63845 or PU-H71 was associated with FLT3-mutated AML and CD34 < 30%. The combination of CA4948 and BH3-mimetics may be effective in the treatment in FLT3-mutated AML with differential target specificity for MCL1 and BCL2 inhibitors. Moreover, the combination of CA4948 and PU-H71 may be a candidate combination treatment in FLT3-mutated AML.
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Mast cells (MCs) in rat airways have been classified into two subtypes: epithelial MCs and connective tissue MCs (CTMCs). However, the immunohistochemical characteristics, cellular morphology, and distribution of epithelial MCs in the upper airways remain unclear. The present study investigated the morphological characteristics and distribution of epithelial MCs using 5-hydroxytryptamine (5-HT) and other immunohistochemical markers in sectioned or whole-mount preparations of the rat larynx and trachea. A double immunofluorescence analysis revealed the colocalization of 5-HT immunoreactivity with c-kit, a stem cell factor receptor commonly used as a MC marker, in both epithelial MCs and CTMCs. Dopa decarboxylase, an enzyme involved in 5-HT synthesis, was detected in both subtypes, suggesting their ability to synthesize and release 5-HT. Tryptase and histidine decarboxylase (a biosynthetic enzyme of histamine), which are well-known mediators of MCs, were exclusive to CTMCs. Epithelial MCs were pleomorphic with long cytoplasmic processes, whereas CTMCs were round and lacked cytoplasmic processes. The density of epithelial MCs was significantly higher in the glottis and cranial part of the trachea than in the epiglottis and other parts of the trachea. The present results showed that the morphology and immunohistochemical characteristics of epithelial MCs were different from those of CTMCs in the rat larynx and trachea, and variform epithelial MCs were predominantly located at the entrance of the upper airways. Epithelial MCs may release 5-HT to regulate innate immune responses by modulating epithelial cell functions at the entrance gate of the upper airways.
Assuntos
Células Epiteliais , Imuno-Histoquímica , Laringe , Mastócitos , Traqueia , Animais , Mastócitos/metabolismo , Mastócitos/citologia , Ratos , Laringe/metabolismo , Laringe/citologia , Traqueia/citologia , Traqueia/metabolismo , Masculino , Células Epiteliais/metabolismo , Células Epiteliais/citologia , Serotonina/metabolismo , Serotonina/análise , Ratos Wistar , Ratos Sprague-Dawley , Proteínas Proto-Oncogênicas c-kit/metabolismo , Proteínas Proto-Oncogênicas c-kit/análiseRESUMO
Stem cell-based therapy has been proposed as a novel therapeutic strategy for diabetic nephropathy. This study was designed to evaluate the effect of systemic administration of rat bone marrow-derived c-kit positive (c-kit+) cells on diabetic nephropathy in male rats, focusing on PI3K/AKT/GSK-3ß pathway and apoptosis as a possible therapeutic mechanism. Twenty-eight animals were randomly classified into four groups: Control group (C), diabetic group (D), diabetic group, intravenously received 50 µl phosphate-buffered saline (PBS) containing 3 × 105 c-kit- cells (D + ckit-); and diabetic group, intravenously received 50 µl PBS containing 3 × 105 c-Kit positive cells (D + ckit+). Control and diabetic groups intravenously received 50 µl PBS. C-kit+ cell therapy could reduce renal fibrosis, which was associated with attenuation of inflammation as indicated by decreased TNF-α and IL-6 levels in the kidney tissue. In addition, c-kit+ cells restored the expression levels of PI3K, pAKT, and GSK-3ß proteins. Furthermore, renal apoptosis was decreased following c-kit+ cell therapy, evidenced by the lower apoptotic index in parallel with the increased Bcl-2 and decreased Bax and Caspase-3 levels. Our results showed that in contrast to c-kit- cells, the administration of c-kit+ cells ameliorate diabetic nephropathy and suggested that c-kit+ cells could be an alternative cell source for attenuating diabetic nephropathy.
Assuntos
Terapia Baseada em Transplante de Células e Tecidos , Nefropatias Diabéticas , Animais , Masculino , Ratos , Apoptose , Medula Óssea/metabolismo , Nefropatias Diabéticas/terapia , Glicogênio Sintase Quinase 3 beta/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Transdução de Sinais , Células-Tronco/metabolismo , Proteínas Proto-Oncogênicas c-kit , Complicações do Diabetes/metabolismo , Células-Tronco Mesenquimais/metabolismo , Terapia Baseada em Transplante de Células e Tecidos/métodosRESUMO
Cranial radiotherapy is a major treatment for leukemia and brain tumors. Our previous study found abscopal effects of cranial irradiation could cause spermatogenesis disorder in mice. However, the exact mechanisms are not yet fully understood. In the study, adult male C57BL/6 mice were administrated with 20â¯Gy X-ray cranial irradiation (5â¯Gy per day for 4 days consecutively) and sacrificed at 1, 2 and 4 weeks. Tandem Mass Tag (TMT) quantitative proteomics of testis was combined with bioinformatics analysis to identify key molecules and signal pathways related to spermatogenesis at 4 weeks after cranial irradiation. GO analysis showed that spermatogenesis was closely related to oxidative stress and inflammation. Severe oxidative stress occurred in testis, serum and brain, while serious inflammation also occurred in testis and serum. Additionally, the sex hormones related to hypothalamic-pituitary-gonadal (HPG) axis were disrupted. PI3K/Akt pathway was activated in testis, which upstream molecule SCF/C-Kit was significantly elevated. Furthermore, the proliferation and differentiation ability of spermatogonial stem cells (SSCs) were altered. These findings suggest that cranial irradiation can cause spermatogenesis disorder through brain-blood-testicular cascade oxidative stress, inflammation and the secretory dysfunction of HPG axis, and SCF/C-kit drive this process through activating PI3K/Akt pathway.
Assuntos
Irradiação Craniana , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Proteínas Proto-Oncogênicas c-kit , Espermatogênese , Animais , Masculino , Espermatogênese/efeitos da radiação , Camundongos , Proteínas Proto-Oncogênicas c-kit/metabolismo , Estresse Oxidativo/efeitos da radiação , Irradiação Craniana/efeitos adversos , Testículo/efeitos da radiação , Testículo/patologia , Transdução de Sinais/efeitos da radiação , Fator de Células-Tronco/metabolismo , InflamaçãoRESUMO
Salivary gland hypofunction adversely affects the oral environment and daily life by causing dry mouth (xerostomia). Senescence-related atrophy of salivary gland tissues is one cause of xerostomia, and it is particularly common among the elderly. However, the underlying mechanism is poorly understood, and no treatment has been established. Therefore, we examined age-related changes in senescence-associated secretory phenotype (SASP) factors, which regulate stemness and cellular senescence, in mouse submandibular glands. We analyzed the submandibular glands of 6-week-old (young group, n = 6) and 82-week-old mice (aged group, n = 6). We performed salivary flow rate measurements, histological analysis including immunohistochemistry, and quantitative real-time PCR. The salivary flow rate was significantly lower in the aged group than in the young group. In addition, immunostaining and quantitative real-time PCR illustrated that aquaporin-5 and α-amylase expressions were significantly decreased in aged mice, indicating salivary gland hypofunction. c-Kit and cytokeratin 5 expressions were also significantly decreased in this group, suggesting that the regenerative abilities of the submandibular glands were reduced because of decreased stem and progenitor cell counts. Furthermore, the levels of p16INK4a and p21 (the senescence markers) and TGF-ß1 and IL-6 (SASP factors) were significantly increased in mice, suggesting that senescence had been promoted. The decreased numbers of stem and progenitor cells and increased levels of SASP factors might be associated with age-related changes in mouse submandibular glands. These results might facilitate the development of treatments for senescence-related submandibular gland hypofunction.
Assuntos
Glândula Submandibular , Xerostomia , Humanos , Idoso , Camundongos , Masculino , Animais , Glândula Submandibular/metabolismo , Glândula Submandibular/patologia , Senescência Celular , Células-TroncoRESUMO
A series of novel echinatin derivatives with 1,3,4-oxadiazole moieties were designed and synthesized. Most of the newly synthesized compounds exhibited moderate antiproliferative activity against the four cancer cell lines. Notably, Compound T4 demonstrated the most potent activity, with IC50 values ranging from 1.71 µM to 8.60 µM against the four cancer cell lines. Cell colony formation and wound healing assays demonstrated that T4 significantly inhibited cell proliferation and inhibited migration. We discovered that T4 exhibited moderate binding affinity with the c-KIT protein through reverse docking. The results were effectively validated through subsequent molecular docking and c-KIT enzyme activity assays. In addition, Western blot analysis revealed that T4 inhibits the phosphorylation of downstream proteins of c-KIT. The results provide valuable inspiration for exploring novel insights into the design of echinatin-related hybrids as well as their potential application as c-KIT inhibitors to enhance the efficacy of candidates.
Assuntos
Antineoplásicos , Chalconas , Neoplasias , Oxidiazóis , Humanos , Relação Estrutura-Atividade , Antineoplásicos/química , Ensaios de Seleção de Medicamentos Antitumorais , Simulação de Acoplamento Molecular , Proliferação de Células , Estrutura Molecular , Linhagem Celular Tumoral , Relação Dose-Resposta a DrogaRESUMO
A promising strategy in cancer immunotherapy is to restore or enhance the cytotoxicity of NK cells, among others, by activating the mechanism of antibody-dependent cellular cytotoxicity (ADCC). Monoclonal antibodies targeting tumor antigens, such as rituximab (targeting CD20), induce NK cell-mediated ADCC and have been used to treat B cell malignancies, such as non-Hodgkin lymphoma, but not always successfully. The aim of this study was to analyze the gene expression profile of the NK cells involved in the cytolytic response stimulated by rituximab. NK cells were co-cultured with rituximab-opsonized Raji cells. Sorting into responder and non-responder groups was based on the presence of CD107a, which is a degranulation marker. RNA-seq results showed that the KIT and TNFSF4 genes were strongly down-regulated in the degranulating population of NK cells (responders); this was further confirmed by qRT-PCR. Both genes encode surface proteins with cellular signaling abilities, namely c-KIT and the OX40 ligand. Consistent with our findings, c-KIT was previously reported to correlate inversely with cytokine production by activated NK cells. The significance of these findings for cancer immunotherapy seems essential, as the pharmacological inhibition of c-KIT and OX40L, or gene ablation, could be further tested for the enhancement of the anti-tumor activity of NK cells in response to rituximab.
Assuntos
Degranulação Celular , Células Matadoras Naturais , Rituximab , Rituximab/farmacologia , Humanos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/metabolismo , Degranulação Celular/efeitos dos fármacos , Ligante OX40/metabolismo , Ligante OX40/genética , Citotoxicidade Celular Dependente de Anticorpos/efeitos dos fármacos , Linhagem Celular Tumoral , Proteína 1 de Membrana Associada ao Lisossomo/metabolismo , Linfócitos B/imunologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/metabolismo , Antineoplásicos Imunológicos/farmacologiaRESUMO
A 2-year-old, male patient presented with an 18-month history of scattered, brown macules and nodules up to 2 cm in size on his trunk and extremities. These macules were accompanied by pruritus and were positive for Darier's sign. A skin biopsy of a brown macule on the left thigh revealed a dense accumulation of CD117-positive, round or oval cells with amphophilic cytoplasm within the upper to middle dermis. The patient was otherwise healthy and had normal laboratory and imaging test results. Sequence analysis of genomic DNA from a skin biopsy demonstrated the presence of an Asp419del mutation in exon 8 of the KIT gene. Based on these findings, maculopapular cutaneous mastocytosis (MPCM) was diagnosed. The patient received H 1-antihistamine. Although the pruritus resolved, the brown macules remained for one year after the initial treatment. To the best of our knowledge, only three cases of cutaneous mastocytosis (CM) with an Asp419del mutation, including the present case, have been reported in the Japanese literature to date; moreover, while the previous two cases were of DCM, the present case was the first instance of MPCM. Normally, the symptoms of childhood-onset MPCM are dormant until puberty. However, a recent study reported that many MPCM patients may experience persistent or exacerbated symptoms. The present study therefore evaluated 53 Japanese cases of childhood onset MPCM with a KIT gene mutation and discussed the patients' clinical outcomes.
Assuntos
Mastocitose Cutânea , Urticaria Pigmentosa , Humanos , Masculino , Pré-Escolar , Urticaria Pigmentosa/diagnóstico , Urticaria Pigmentosa/genética , Urticaria Pigmentosa/patologia , Mastocitose Cutânea/diagnóstico , Mastocitose Cutânea/genética , Mastocitose Cutânea/patologia , Pele/patologia , Mutação , PruridoRESUMO
BACKGROUND: A challenge in human mammary epithelial cell (HMEC) culture is sustaining the representation of competing luminal, myoepithelial, and progenitor lineages over time. As cells replicate in culture, myoepithelial cells come to dominate the composition of the culture with serial passaging. This drift in composition presents a challenge for studying luminal and progenitor cells, which are prospective cells of origin for most breast cancer subtypes. METHODS: We demonstrate the use of postconfluent culture on HMECs. Postconfluent culture entails culturing HMECs for 2-5 weeks without passaging but maintaining frequent feedings in low-stress M87A culture medium. In contrast, standard HMEC culture entails enzymatic subculturing every 3-5 days to maintain subconfluent density. RESULTS: When compared to standard HMEC culture, postconfluent culture yields increased proportions of luminal cells and c-Kit+ progenitor cells. Postconfluent cultures develop a distinct multilayered morphology with individual cells showing decreased physical deformability as compared to cells in standard culture. Gene expression analysis of postconfluent cells shows increased expression of lineage-specific markers and extracellular matrix components. CONCLUSIONS: Postconfluent culture is a novel, useful strategy for altering the lineage composition of HMECs, by increasing the proportional representation of luminal and progenitor cells. We speculate that postconfluent culture creates a microenvironment with cellular composition closer to the physiological state and eases the isolation of scarce cell subtypes. As such, postconfluent culture is a valuable tool for researchers using HMECs for breast cancer research.
Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Mama , Células Epiteliais/metabolismo , Microambiente TumoralRESUMO
The main function of interstitial cells of Cajal (ICCs) is to regulate gastrointestinal peristalsis by acting as a "pacemaker" cell by generating spontaneous slow electrical waves. In 2005, electron microscopy revealed a cell type similar to ICCs (ICC-like) outside the gastrointestinal tract, with contractile activity and c-Kit+ immunohistochemistry shared with ICCs. Among the locations where ICC-like cells have been observed, it is in the uterus where they have a significant functional and pathophysiological role. These cells are involved in obstetric phenomena of contractile action, such as ascending sperm transport, embryo implantation, pregnancy, delivery, and the expulsion of menstrual debris. Within the pathophysiology related to these cells, we find obstetric alterations such as recurrent miscarriages, premature deliveries, abolition of uterine contractions, and failures of embryo implantation, in addition to other common conditions in the fertile age, such as endometriosis and leiomyoma.
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Targeting the molecular chaperone HSP90 and the anti-apoptotic proteins MCL1 and BCL2 may be a promising novel approach in the treatment of acute myeloid leukemia (AML). The HSP90 inhibitor PU-H71, MCL1 inhibitor S63845, and BCL2 inhibitor venetoclax were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells. AML cells represented all major morphologic and molecular subtypes including FLT3-ITD and TP53 mutant AML cell lines and a variety of patient-derived AML cells. Results: PU-H71 and combination treatments with MCL1 inhibitor S63845 or BCL2 inhibitor venetoclax induced cell cycle arrest and apoptosis in susceptible AML cell lines and primary AML. The majority of the primary AML samples were responsive to PU-H71 in combination with BH3 mimetics. Elevated susceptibility to PU-H71 and S63845 was associated with FLT3 mutated AML with CD34 < 20%. Elevated susceptibility to PU-H71 and venetoclax was associated with primary AML with CD117 > 80% and CD11b < 45%. The combination of HSP90 inhibitor PU-H71 and MCL1 inhibitor S63845 may be a candidate treatment for FLT3-mutated AML with moderate CD34 positivity while the combination of HSP90 inhibitor PU-H71 and BCL2 inhibitor venetoclax may be more effective in the treatment of primitive AML with high CD117 and low CD11b positivity.
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BACKGROUND: Chronic inflammation, mainly derived from fibroblast-like synoviocytes (FLSs), plays a central role in the pathomechanism of osteoarthritis (OA). Recently, epithelial-mesenchymal transition (EMT) signaling was found to be activated in OA-derived FLSs with a pro-inflammatory phenotype. However, the role of EMT signaling in regulating FLS function and OA-related inflammation remains unknown. METHODS: The synovium of OA patients were evaluated for EMT and inflammation markers. The FLSs with activated EMT signaling were co-cultured with chondrocytes (chond). Gene expression of OA synovial samples were analyzed. The role of receptor tyrosine kinase C-kit was investigated in OA-FLSs and an OA rat model. The downstream pathways driven by C-kit were explored in OA-FLSs. RESULTS: EMT marker N-cadherin (N-CDH) was upregulated in 40.0% of the OA samples. These N-CDH+ OA samples showed higher expression of pro-inflammatory factors. In co-culture, FLSs derived from N-CDH+ OA samples induced a typical degenerative phenotype of chonds and stimulated their production of matrix degrading enzymes. C-kit was significantly upregulated and spatially co-localized with N-CDH in N-CDH+ OA samples. In OA-FLSs, C-kit activated intracellular EMT signaling and induced destructive features of OA-FLSs. In OA rat model, C-kit largely promoted synovial inflammation and cartilage destruction, whereas knocking-down C-kit significantly restored the health of OA joints. Using GSK3ß S9A mutant, we demonstrated that C-kit drives EMT signaling in OA-FLS by promoting phosphorylation of GSK3ß and nuclear retention of the EMT transcription factor Snail. CONCLUSION: C-kit drives EMT signaling in OA-FLSs and promotes a destructive FLS phenotype, leading to synovial inflammation and cartilage destruction.
Assuntos
Transição Epitelial-Mesenquimal , Osteoartrite , Ratos , Animais , Glicogênio Sintase Quinase 3 beta/genética , Osteoartrite/metabolismo , Membrana Sinovial/metabolismo , Inflamação/metabolismo , Fenótipo , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Fibroblastos/metabolismo , Células CultivadasRESUMO
PURPOSE: The study was conducted to investigate the effect of the treatment with imatinib, a c-kit specific inhibitor, on the neointimal hyperplasia (NIH) of aortocaval fistula (ACF) in adenine-induced renal failure rats. MATERIALS AND METHODS: All rats were randomly assigned to 4 groups: rats were fed on a normal diet (normal group); rats were fed on a 0.75% adenine-rich diet (renal failure group). The remaining rats underwent ACF after receiving a 0.75% adenine-rich diet and received daily saline gavage (model group) or imatinib gavage (imatinib group) for 7 days after surgery. Immunohistochemical method was used to detect c-kit expression, and Elastomeric Verhoeff-Van Gieson (EVG) staining was used to observe morphological changes of the ACF. The Pearson correlation analysis was used to evaluate the correlations of c-kit expression with intimal thickness and the percentage of stenosis, respectively. RESULTS: The renal failure group showed positive c-kit expression on the intima of the inferior vena cava (IVC), whereas the normal group did not. Compared to the model group, intimal thickness (P = 0.001), the percentage of stenosis (P = 0.006) and c-kit expression (P = 0.04) were decreased in the imatinib group at 8 weeks postoperatively. C-kit expression was positively correlated with both intimal thickness and percentage of stenosis (intimal thickness: R = 0.650, P = 0.003; the percentage of stenosis: R = 0.581, P = 0.011) in both the model and imatinib groups. CONCLUSION: Treatment with imatinib, a c-kit specific inhibitor, was useful to delay the NIH of ACF in adenine-induced renal failure rats.
Assuntos
Fístula , Insuficiência Renal , Ratos , Animais , Mesilato de Imatinib , Hiperplasia , Constrição Patológica , Neointima , Proteínas Proto-Oncogênicas c-kitRESUMO
Oncoprotein AML1-ETO (AE) derived from t(8;21)(q22;q22) translocation is typically present in a portion of French-American-British-M2 subtype of acute myeloid leukemia (AML). Although these patients have relatively favorable prognoses, substantial numbers of them would relapse after conventional therapy. Here, we explored whether reinforcing the endogenous differentiation potential of t(8;21) AML cells would diminish the associated malignancy. In doing so, we noticed an expansion of immature erythroid blasts featured in both AML1-ETO9a (AE9a) and AE plus c-KIT (N822K) (AK) murine leukemic models. Interestingly, in the AE9a murine model, a spontaneous step-wise erythroid differentiation path, as characterized by the differential expression of CD43/c-Kit and the upregulation of several key erythroid transcription factors (TFs), accompanied the decline or loss of leukemia-initiating potential. Notably, overexpression of one of the key erythroid TFs, Ldb1, potently disrupted the repopulation of AE9a leukemic cells in vivo, suggesting a new promising intervention strategy of t(8;21) AML through enforcing their erythroid differentiation.
Assuntos
Leucemia Mieloide Aguda , Proteínas de Fusão Oncogênica , Animais , Cromossomos Humanos Par 21 , Cromossomos Humanos Par 8 , Proteínas de Ligação a DNA/metabolismo , Humanos , Proteínas com Domínio LIM , Proteínas com Homeodomínio LIM , Leucemia Mieloide Aguda/metabolismo , Camundongos , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteína 1 Parceira de Translocação de RUNX1/genética , Translocação GenéticaRESUMO
Given that mast cells are pivotal contributors to allergic diseases, various allergy treatments have been developed to inhibit them. Omalizumab, an anti-immunoglobulin E antibody, is a representative therapy that can alleviate allergy symptoms by inhibiting mast cell degranulation. However, omalizumab cannot reduce the proliferation and accumulation of mast cells, which is a fundamental cause of allergic diseases. c-Kit is essential for the proliferation, survival, and differentiation of mast cells. Excessive c-Kit activation triggers various mast cell diseases, such as asthma, chronic spontaneous urticaria, and mastocytosis. Herein, we generated 2G4, an anti-c-Kit antibody, to develop a therapeutic agent for mast cell diseases. The therapeutic efficacy of 2G4 antibody was evaluated in LAD2, a human mast cell line. 2G4 antibody completely inhibited c-Kit signaling by blocking the binding of stem cell factor, known as the c-Kit ligand. Inhibition of c-Kit signaling led to the suppression of proliferation, migration, and degranulation in LAD2 cells. Moreover, 2G4 antibody suppressed the secretion of pro-inflammatory cytokines, including granulocyte-macrophage colony-stimulating factor, vascular endothelial growth factor, C-C motif chemokine ligand 2, brain-derived neurotrophic factor, and complement component C5/C5a, which can exacerbate allergy symptoms. Taken together, these results suggest that 2G4 antibody has potential as a novel therapeutic agent for mast cell diseases.
Assuntos
Hipersensibilidade , Transtornos da Ativação de Mastócitos , Humanos , Mastócitos/metabolismo , Omalizumab/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Fator de Células-Tronco/metabolismo , Hipersensibilidade/metabolismo , Proliferação de Células , Degranulação CelularRESUMO
AIM: was to assess the role of C-KIT, TET1 and TET2 expression in the diagnosis and prognosis of acute myeloblastic leukemia (AML). METHODS: The expression levels of C-KIT, TET1 and TET2 were assessed in the bone marrow (BM) aspirate of 152 AML patients compared to 20 healthy control using quantitative real-time polymerase chain reaction (qRT-PCR). Data were correlated with the clinico-pathological features of the patients, response to treatment, disease-free survival (DFS), and overall survival (OS) rates. RESULTS: C-KIT, TET1 and TET2 were significantly upregulated in AML patients [0.25 (0-11.6), 0.0113 (0-3.301), and 0.07 (0-4); respectively], compared to the control group [0.013 (0.005-0.250), P < 0.001, 0.001 (0-0.006), P < 0.001, and 0.02 (0.008-0.055), P = 0.019; respectively]. The sensitivity, specificity, and area under curve of of C-KIT were (48.7%, 100%, 0.855; respectively, P = 0.001), and that of TET1 were (63.4%, 100%, 0.897; respectively, P = 0.001), while that of TET2 were (56.8%, 100%, 0.766; respectively, P = 0.019). When combining the three markers, the sensitivity was 77.5%, however it reached the highest sensitivity (78.6%) and specificity (100%) when combining both c-KIT + TET1 together for the diagnosis of AML. C-KIT overexpression associated with shorter DFS (P = 0.05) and increased incidence of relapse (P = 0.019). Lymph nodes involvement [HR = 2.200, P = 0.005] is an independent risk factor for shorter OS rate of AML patients. Increased BM blast % [HR = 7.768, P = 0.002], and FLT3-ITD mutation [HR = 2.989, P = 0.032] are independent risk factors for shorter DSF rate of the patients. CONCLUSION: C-KIT, TET1, and TET2 could be used as possible useful biomarkers for the diagnosis of AML.