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Glioblastoma multiforme (GBM) is a grade IV, highly malignant brain tumor. Because of the heterogeneity of GBM, a multitarget drug is a rational strategy for GBM treatment. Histone deacetylase inhibitors (HDACis) regulate the expression of numerous genes involved in cell death, apoptosis, and tumorigenesis. We found that the HDAC4/HDAC5 inhibitor LMK235 at 0.5 µM significantly reduced the cell viability and colony formation of patient-derived, temozolomide-resistant GBM P#5 TMZ-R, U-87 MG, and T98G cells. Moreover, LMK235 also significantly increased TUBA acetylation, which is an indicator of HDAC inhibition. Interestingly, LMK235 induced MAP1LC3 robust readout and puncta accumulation but did not enhance PARP1 cleavage or the proportion of annexin V-positive cells, suggesting that LMK235-induced cell death occurred via autophagy activation. Further RNA-seq analysis after LMK235 treatment showed that 597 different expression genes compared to control. After bioinformatic analysis by KEGG and STRING, we focused on 34 genes and validated their mRNA expression by qPCR. Further validation showed that 2 µM LMK235 significantly reduced the mRNA and protein expression of SCNN1A. Cell viability of SCNN1A-silenced cells were reduced, but cells were rescued while treated with an autophagy inhibitor bafilomycin A1. Conclusively, SCNN1A plays a role in LMK235-induced autophagy and cell death in GBM cells.
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Patients with bipolar disorder (BD) exhibit individual variability in the treatment outcome, and genetic background could contribute to BD itself and the treatment outcome. Leptin levels significantly change in BD patients treated with valproate (VPA), but whether LEPR polymorphisms are associated with treatment response is still unknown. This longitudinal study aimed to investigate the associations between LEPR polymorphisms and VPA treatment response in BD patients who were drug naïve at their first diagnosis of BD. The single-nucleotide polymorphisms (SNPs) of LEPR (rs1137101, rs1137100, rs8179183, and rs12145690) were assayed, and the LEPR polymorphism frequencies of alleles and genotypes were not significantly different between the controls (n = 77) and BD patients (n = 130). In addition, after the 12-week course of VPA treatment in BD patients, the LEPR polymorphisms showed significant effects on changes in disease severity. Moreover, considering the effect of the LEPR haplotype, the frequency of the CAGG haplotype in BD patients was higher than that in the controls (9.3 vs. 2.9%, p = 0.016), and the LEPR CAGG haplotype was associated with a better treatment response than the other haplotypes in BD patients receiving VPA treatment. Therefore, LEPR polymorphisms might serve as mediators involved in the therapeutic action of VPA treatment.
Assuntos
Transtorno Bipolar , Receptores para Leptina , Transtorno Bipolar/tratamento farmacológico , Transtorno Bipolar/genética , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Haplótipos , Humanos , Leptina/genética , Estudos Longitudinais , Polimorfismo de Nucleotídeo Único , Receptores para Leptina/genéticaRESUMO
It is a challenge to obtain sufficient eggs during in vitro fertilization (IVF) in women with impending ovarian failure (IOF)/diminished ovarian reserve (DOR). Although studies have suggested that more than one wave of follicle growth exists, the efficacy of controlled ovulation stimulation (COS) in both follicular and luteal phases of the same ovarian cycle (DuoStim) is not established in women with IOF/DOR. We investigated the efficacy of DuoStim using the intraovarian injection of recombinant human follicle-stimulating hormone (rhFSH) during oocyte retrieval in women with DOR. For luteal-phase stimulation, intraovarian (Group A, N = 28) or superficial subcutaneous (Group B, N = 18) injection of 300 IU rhFSH immediately after oocyte retrieval was administered as the first dose, and intermittent superficial subcutaneous addition of gonadotropins was employed accordingly for further COS in both groups. In Group A, significantly lower Gn doses, a shorter duration of COS, a greater number of antral follicle counts, and an increased number of retrieved mature and total oocytes were noted. Compared with the clinical outcomes of luteal-phase COS, the average daily doses of rhFSH used in Group A were significantly lower. In summary, the novel approach using intraovarian rhFSH injection provides an efficient treatment regimen in women with IOF/DOR.
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It is a challenge to obtain enough oocytes during in vitro fertilization (IVF) in women who have a poor ovarian response (POR) in achieving conception. We have adopted the characteristics of the first uterine pass effect, which we pioneered in employing the vaginal administration of gonadotropins in women receiving IVF treatments. In our previous study employing vaginal administration, faster absorption and slower elimination of gonadotropins were demonstrated, and, female subjects presented proper ovarian follicle growth and pregnancy rates. In this study, during 2016-2020, 300 to 675 IU of gonadotropins were administered vaginally every three days in 266 POR women for their controlled ovarian hyperstimulation (COH). The injections were performed with needles angled at 15-30° towards the middle-upper portions of the bilateral vaginal wall, with an injection depth of 1-2 mm. For the COH results, these women, on average, received 3.0 ± 0.9 vaginal injections and a total dose of 1318.4 ± 634.4 IU gonadotropins, resulting in 2.2 ± 1.9 mature oocytes and 1.0 ± 1.2 good embryos. Among these embryos, 0.9 ± 1.0 were transferred to reach a clinical pregnancy rate of 18.1% and a live birth rate of 16.7%. In conclusion, the intermittent vaginal administration of gonadotropins proved to be effective in POR women for their IVF treatments.
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AIMS: Glioblastoma (GBM) is a highly malignant brain tumor. After treatment with the first-line drug temozolomide, only 50% of patients are responsive. Recent literature shows that the difficulty in treating GBM is mainly due to the heterogeneity of its four major cellular states, which are characterized by differences in EGFR, PDGFRA, CDK4, and NF1. Therefore, development of a multitarget drug is a potential strategy for treating heterogeneous GBM. MAIN METHODS: In this study, the antitumor ability of a potent heat shock protein 90 inhibitor, NVP-AUY922 (AUY922), was evaluated in GBM cell lines (U-87 MG and T98G cells) and patient-derived GBM cell lines [P#5 and P#5 temozolomide-resistant (TMZ-R) cells]. KEY FINDINGS: We found that AUY922 significantly reduced cell viability and colony formation in four GBM cell lines. AUY922 also significantly induced apoptosis by increasing PARP1 cleavage and the number of annexin V-positive cells. The autophagy indicators as MAP1LC3B cleavage and MAP1LC3B puncta were increased after AUY922 treatment. AUY922-induced cell death could be partially reversed by pharmacological inhibition of either apoptotic inhibitor or autophagy inhibitor. Moreover, AUY922 reduced the mRNA and protein expressions of EGFR, PDGFRA, CDK4, and NF1, which contribute to the four cellular state subtypes in GBM cells. In addition, the downstream signaling proteins of these four proteins, AKT/p-AKT, MAPK/p-MAPK, and BRAF, were downregulated after AUY922 treatment. SIGNIFICANCE: Taken together, AUY922 led to GBM cell death via apoptosis and autophagy, and reduced the mRNA and protein expression of EGFR, PDGFRA, CDK4, and NF1in heterogeneous GBM cells.
Assuntos
Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioblastoma/tratamento farmacológico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Isoxazóis/farmacologia , Neurofibromina 1/antagonistas & inibidores , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Resorcinóis/farmacologia , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Proliferação de Células , Quinase 4 Dependente de Ciclina/genética , Quinase 4 Dependente de Ciclina/metabolismo , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Receptores ErbB/metabolismo , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Neurofibromina 1/genética , Neurofibromina 1/metabolismo , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Células Tumorais CultivadasRESUMO
The uterine first-pass effect occurs when drugs are delivered vaginally. However, the effect of vaginally administered recombinant human follicle-stimulating hormone (rhFSH) on ovarian folliculogenesis and endometrial receptivity is not well established. We aimed to compare the efficacy of rhFSH administered vaginally and abdominally in clinical in vitro fertilization (IVF) treatment, pharmacokinetic study, and animal study. In IVF treatment, the number of oocytes retrieved, endometrial thickness and uterine artery blood perfusion were not different between women who received the rhFSH either vaginally or abdominally. For serum pharmacokinetic parameters, significantly lower Tmax, clearance, and higher AUC and T1/2_elimination of rhFSH were observed in women who received rhFSH vaginally, but urine parameters were not different. Immature female rats that received daily abdominal or vaginal injections (1 IU twice daily for 4 days) or intermittent vaginal injections (4 IU every other day for two doses) of rhFSH had more total follicles than the control group. In addition, the serum progesterone and progesterone receptors in the local endometrium were significantly higher in the groups treated with intermittent abdominal or vaginal injection of rhFSH, compared with those who recieved daily injection. In summary, vaginal administration of rhFSH may provide an alternative treatment regimen in women receiving IVF.
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Endométrio/fisiologia , Fertilização in vitro/métodos , Hormônio Foliculoestimulante Humano/administração & dosagem , Infertilidade Feminina/terapia , Folículo Ovariano/citologia , Proteínas Recombinantes/administração & dosagem , Útero/fisiologia , Adulto , Animais , Estudos Cross-Over , Endométrio/efeitos dos fármacos , Feminino , Humanos , Pessoa de Meia-Idade , Folículo Ovariano/fisiologia , Ratos , Ratos Sprague-Dawley , Injeções de Esperma Intracitoplásmicas , Útero/efeitos dos fármacos , Vagina/efeitos dos fármacos , Vagina/fisiologiaRESUMO
Recombinant human thrombomodulin (rhTM), an angiogenesis factor, has been demonstrated to stimulate cell proliferation, keratinocyte migration and wound healing. The objective of this study was to develop nanostructured lipid carrier (NLC) formulations encapsulating rhTM for promoting chronic wound healing. RhTM-loaded NLCs were prepared and characterized. Encapsulation efficiency was more than 92%. The rate of rhTM release from different NLC formulations was influenced by their lipid compositions and was sustained for more than 72 h. Studies on diabetic mouse wound model suggested that rhTM-NLC 1.2 µg accelerated wound healing and was similar to recombinant human epidermal growth factor-NLC (rhEGF-NLC) 20 µg. By incorporating 0.085% carbopol (a highly crosslinked polyacrylic acid polymer) into rhTM NLC, the NLC-gel presented similar particle characteristics, and demonstrated physical stability, sustained release property and stability within 12 weeks. Both rhTM NLC and rhTM NLC-gel improved wound healing of diabetic mice and cell migration of human epidermal keratinocyte cell line (HaCaT) significantly. In comparison with rhTM solution, plasma concentrations of rhTM post applications of NLC and NLC-gel formulations were lower and more sustained in 24 h. The developed rhTM NLC and rhTM NLC-gel formulations are easy to prepare, stable and convenient to apply to the wound with reduced systemic exposure, which may warrant potential delivery systems for the care of chronic wound patients.
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BACKGROUND: Previous studies suggested that a disturbance of the dopamine system underlies the pathophysiology of bipolar disorder (BD). In addition, the therapeutic action of medications for treating BD, such as valproate (VPA), might modulate dopamine system activity, but it remains unclear. Here, we aimed to investigate the role of the striatal dopamine transporter (DAT) in BD patients and in social defeat (SD) mice treated with VPA. METHODS: We enrolled community-dwelling controls (N = 18) and BD patients (N = 23) who were treated with VPA in a euthymic stage. The striatal DAT availabilities were approached by TRODAT-1 single photon emission computed tomography. We also established a chronic SD mouse model and treated mice with 350 mg/kg VPA for 3 weeks. Behavioral tests were administered, and striatal DAT expression levels were determined. RESULTS: In humans, the level of striatal DAT availability was significantly higher in euthymic BD patients (1.52 ± 0.17 and 1.37 ± 0.23, p = 0.015). Moreover, the level of striatal DAT availability was also negatively correlated with the VPA concentration in BD patients (r = -0.653, p = 0.003). In SD mice, the expression of striatal DAT significantly increased (p < 0.001), and the SD effect on DAT expression was rescued by VPA treatment. CONCLUSIONS: The striatal DAT might play a role in the pathophysiology of BD and in the therapeutic mechanism of VPA. The homeostasis of DAT might represent a new therapeutic strategy for BD patients.
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Transtorno Bipolar , Proteínas da Membrana Plasmática de Transporte de Dopamina , Ácido Valproico/uso terapêutico , Animais , Transtorno Bipolar/tratamento farmacológico , Corpo Estriado/metabolismo , Dopamina , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Humanos , Camundongos , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Gastrointestinal stromal tumors (GISTs) are frequently driven by auto-activated, mutant KIT and have durable response to KIT tyrosine kinase inhibitor. However, acquired resistance is an increasing clinical issue in GIST patients receiving front-line imatinib therapy. Our previous studies showed the colocalization of KIT with DAPI-stained nuclei in GIST cells without knowing the role of nuclear KIT in GIST tumorigenesis. In this article, we first identified the binding of nuclear KIT to the promoter of NFKB inhibitor beta (NFKBIB) by chromatin immunoprecipitation (ChIP) sequencing and ChIP assays, which was accompanied with enhanced NFKBIB protein expression in GIST cells. Clinically, high NCCN risk GISTs had significantly higher mean expression levels of nuclear phospho-KIT and NFKBIB as compared with those of intermediate or low/very low-risk GISTs. Conversely, downregulation of NFKBIB by siRNA led to RELA nuclear translocation that could bind to the KIT promoter region and subsequently reduced KIT transcription/expression and the viability of GIST cells. These findings were further confirmed by either RELA overexpression or NFKB/RELA inducer, valproic acid, treatment to result in reduced KIT expression and relative cell viability of imatinib-resistant GIST cells. Combining valproic acid with imatinib showed significantly better growth inhibitory effects on imatinib-resistant GIST48 and GIST430 cells in vitro, and in the GIST430 animal xenograft model. Taken together, these results demonstrate the existence of a nuclear KIT-driven NFKBIB-RELA-KIT autoregulatory loop in GIST tumorigenesis, which are potential targets for developing combination therapy to overcome imatinib-resistant of KIT-expressing GISTs.
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Resistencia a Medicamentos Antineoplásicos , Neoplasias Gastrointestinais , Tumores do Estroma Gastrointestinal , Proteínas I-kappa B/metabolismo , Mesilato de Imatinib/uso terapêutico , Proteínas Proto-Oncogênicas c-kit/fisiologia , Fator de Transcrição RelA/metabolismo , Animais , Células COS , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Chlorocebus aethiops , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Retroalimentação Fisiológica/efeitos dos fármacos , Retroalimentação Fisiológica/fisiologia , Neoplasias Gastrointestinais/tratamento farmacológico , Neoplasias Gastrointestinais/genética , Neoplasias Gastrointestinais/metabolismo , Neoplasias Gastrointestinais/patologia , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Tumores do Estroma Gastrointestinal/genética , Tumores do Estroma Gastrointestinal/metabolismo , Tumores do Estroma Gastrointestinal/patologia , Homeostase/efeitos dos fármacos , Homeostase/genética , Humanos , Mesilato de Imatinib/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
Insulin-sensitizer treatment with metformin is widely used in polycystic ovary syndrome (PCOS). However, the treatment effectiveness shows individual differences in PCOS patients. Organic cation transporter (OCT) 1 and 2 have been reported to mediate metformin transport in the liver and kidney, respectively. In this study, we investigated the association between the polymorphisms of OCT1 and OCT2 and the treatment effectiveness of metformin in PCOS patients. The single nucleotide polymorphisms (SNPs) of OCT1 (rs683369 and rs628031) and OCT2 (rs316019) were analyzed in 87 PCOS and 113 control women. Oral glucose tolerance tests (OGTTs), which represented metformin treatment response, were conducted at the start of treatment and after six-month treatment. The results demonstrated that the SNP frequencies of OCT1 and OCT2 were not associated with PCOS pathophysiology, and that the polymorphisms of OCT1 and OCT2 were not associated with the OGTT parameters at baseline. However, PCOS patients with the G allele of OCT1 rs683369 and/or with the A allele of OCT1 rs628031 had increased insulin sensitivity compared to those with wild-type genotype after receiving metformin treatment. Moreover, the interactions of metformin*SNP were significant in both OCT1 rs683369 (p < 0.001) and rs628031 (p = 0.001) during the treatment period. Taken together, genetic polymorphisms of OCT1 contributed to different metformin treatment responses, and further study is needed to establish personalized treatment programs using a pharmacogenomic algorithm approach in PCOS patients.
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Metformina/uso terapêutico , Transportador 1 de Cátions Orgânicos/genética , Transportador 1 de Cátions Orgânicos/metabolismo , Síndrome do Ovário Policístico/tratamento farmacológico , Síndrome do Ovário Policístico/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto , Alelos , Feminino , Genótipo , Teste de Tolerância a Glucose , Humanos , Hipoglicemiantes/uso terapêutico , Resistência à Insulina , Masculino , Transportador 2 de Cátion Orgânico/genética , Estudos ProspectivosRESUMO
PURPOSE: KIT mutations, the most prevalent genetic event in gastrointestinal stromal tumors (GIST), are associated with malignant features and poor prognosis. Aggressive GISTs possess a high propensity to spread to the liver. This study aimed to explore the role of KIT mutations in GIST liver metastasis. EXPERIMENTAL DESIGN: A total of 170 GISTs were used to determine the association between KIT mutations and liver metastasis. Immunohistochemistry was performed to assess the correlation of KIT mutations with CXCR4 and ETV1 expression. Genetic and pharmacologic methods were used to study the regulation of CXCR4 and ETV1 by KIT mutations. RESULTS: Codons 557 and 558 in KIT exon 11 were deletion hot spots in GISTs. KIT exon 11 deletions involving codons 557-558 were highly associated with liver metastasis. Overexpression of mutant KIT with exon 11 codons 557-558 deletion (KIT Δ557-558) increased GIST cell motility and liver metastasis. Mechanistically, overexpression of KIT Δ557-558 in GIST cells increased ETV1 and CXCR4 expression. CXCR4 knockdown counteracted KIT Δ557-558-mediated cell migration. Moreover, KIT Δ557-558-induced CXCR4 expression could be abolished by silencing ETV1. The chromatin immunoprecipitation assay showed that ETV1 directly bound to the CXCR4 promoter. After ERK inhibitor PD325901 treatment, the upregulation of ETV1 by KIT Δ557-558 was prevented. In addition, KIT exon 11 codons 557-558 deletion enhanced CXCL12-mediated GIST cell migration and invasion. CONCLUSIONS: KIT exon 11 557-558 deletion upregulates CXCR4 through increased binding of ETV1 to the CXCR4 promoter in GIST cells, which thus promotes liver metastasis. These findings highlighted the potential therapeutic targets for metastatic GISTs. Clin Cancer Res; 22(14); 3477-87. ©2016 AACR.
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Quimiocina CXCL12/genética , Tumores do Estroma Gastrointestinal/genética , Neoplasias Hepáticas/genética , Mutação/genética , Proteínas Proto-Oncogênicas c-kit/genética , Receptores CXCR4/genética , Deleção de Sequência/genética , Animais , Linhagem Celular Tumoral , Códon/genética , Éxons/genética , Tumores do Estroma Gastrointestinal/patologia , Humanos , Imuno-Histoquímica/métodos , Fígado/patologia , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Transdução de Sinais/genéticaRESUMO
Our previous study demonstrated NVP-AUY922, a HSP90AA1 inhibitor, could enhance mutant KIT degradation in gastrointestinal stromal tumor (GIST) cells through both proteasome- and autophagy-mediated pathways. Herein, we showed rapamycin, a MTOR inhibitor and autophagy inducer, could reduce total and phospho-KIT expression levels and enhance apoptosis in imatinib-resistant GIST cells. The involvement of autophagy in rapamycin-induced KIT downregulation was further confirmed by co-localization of KIT and autophagosome, and partial recovery of KIT expression level by either siRNA-mediated BECN1 and ATG5 silencing or autophagy inhibitors after rapamycin. Rapamycin and NVP-AUY922 synergistically inhibited GIST cells growth in vitro. The combination of low-dose NVP-AUY922 with rapamycin had comparable effects on reducing KIT expression, increasing MAP1LC3B puncta and tumor necrosis, and inhibiting tumor growth as high-dose NVP-AUY922 did in GIST430 xenograft model. Our results suggest the addition of a MTOR inhibitor may reduce NVP-AUY922 dose requirement and potentially improve its therapeutic index in mutant KIT-expressing GISTs.
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Antineoplásicos/química , Autofagia , Resistencia a Medicamentos Antineoplásicos , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Proteínas Proto-Oncogênicas c-kit/metabolismo , Serina-Treonina Quinases TOR/antagonistas & inibidores , Animais , Apoptose , Benzamidas/química , Morte Celular , Sobrevivência Celular , Regulação para Baixo , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Mesilato de Imatinib , Imuno-Histoquímica , Concentração Inibidora 50 , Isoxazóis/química , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mutação , Necrose , Transplante de Neoplasias , Piperazinas/química , Pirimidinas/química , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Resorcinóis/química , Sirolimo/químicaRESUMO
Advanced gastrointestinal stromal tumors (GIST), a KIT oncogene-driven tumor, on imatinib mesylate (IM) treatment may develop secondary KIT mutations to confer IM-resistant phenotype. Second-line sunitinib malate (SU) therapy is largely ineffective for IM-resistant GISTs with secondary exon 17 (activation-loop domain) mutations. We established an in vitro cell-based platform consisting of a series of COS-1 cells expressing KIT cDNA constructs encoding common primary±secondary mutations observed in GISTs, to compare the activity of several commercially available tyrosine kinase inhibitors on inhibiting the phosphorylation of mutant KIT proteins at their clinically achievable plasma steady-state concentration (Css). The inhibitory efficacies on KIT exon 11/17 mutants were further validated by growth inhibition assay on GIST48 cells, and underlying molecular-structure mechanisms were investigated by molecular modeling. Our results showed that SU more effectively inhibited mutant KIT with secondary exon 13 or 14 mutations than those with secondary exon 17 mutations, as clinically indicated. On contrary, at individual Css, nilotinib and sorafenib more profoundly inhibited the phosphorylation of KIT with secondary exon 17 mutations and the growth of GIST48 cells than IM, SU, and dasatinib. Molecular modeling analysis showed fragment deletion of exon 11 and point mutation on exon 17 would lead to a shift of KIT conformational equilibrium toward active form, for which nilotinib and sorafenib bound more stably than IM and SU. In current preclinical study, nilotinib and sorafenib are more active in IM-resistant GISTs with secondary exon 17 mutation than SU that deserve further clinical investigation.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Gastrointestinais/tratamento farmacológico , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-kit/genética , Motivos de Aminoácidos , Animais , Benzamidas/farmacologia , Células COS , Chlorocebus aethiops , Dasatinibe , Resistencia a Medicamentos Antineoplásicos/genética , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ligação de Hidrogênio , Mesilato de Imatinib , Indóis/farmacologia , Simulação de Acoplamento Molecular , Mutação de Sentido Incorreto , Piperazinas/farmacologia , Ligação Proteica , Proteínas Proto-Oncogênicas c-kit/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-kit/química , Pirimidinas/farmacologia , Pirróis/farmacologia , Sunitinibe , Tiazóis/farmacologiaRESUMO
Gastrointestinal stromal tumor (GIST) is a prototype of mutant KIT oncogene-driven tumor. Prolonged tyrosine kinase inhibitor (TKI) treatment may result in a resistant phenotype through acquired secondary KIT mutation. Heat shock protein 90 (HSP90AA1) is a chaperone protein responsible for protein maturation and stability, and KIT is a known client protein of HSP90AA1. Inhibition of HSP90AA1 has been shown to destabilize KIT protein by enhancing its degradation via the proteasome-dependent pathway. In this study, we demonstrated that NVP-AUY922 (AUY922), a new class of HSP90AA1 inhibitor, is effective in inhibiting the growth of GIST cells expressing mutant KIT protein, the imatinib-sensitive GIST882 and imatinib-resistant GIST48 cells. The growth inhibition was accompanied with a sustained reduction of both total and phosphorylated KIT proteins and the induction of apoptosis in both cell lines. Surprisingly, AUY922-induced KIT reduction could be partially reversed by pharmacological inhibition of either autophagy or proteasome degradation pathway. The blockade of autophagy alone led to the accumulation of the KIT protein, highlighting the role of autophagy in endogenous KIT turnover. The involvement of autophagy in endogenous and AUY922-induced KIT protein turnover was further confirmed by the colocalization of KIT with MAP1LC3B-, acridine orange- or SQSTM1-labeled autophagosome, and by the accumulation of KIT in GIST cells by silencing either BECN1 or ATG5 to disrupt autophagosome activity. Therefore, the results not only highlight the potential application of AUY922 for the treatment of KIT-expressing GISTs, but also provide the first evidence for the involvement of autophagy in endogenous and HSP90AA1 inhibitor-induced KIT degradation.