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1.
Cells ; 12(23)2023 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-38067195

RESUMO

Surgery-induced tumor growth acceleration and synchronous metastatic growth promotion have been observed for decades. Surgery-induced wound healing, orchestrated through growth factors, chemokines, and cytokines, can negatively impact patients harboring residual or metastatic disease. We provide detailed clinical evidence of this process in surgical breast, prostate, and colorectal cancer patients. Plasma samples were analyzed from 68 cancer patients who had not received treatment before surgery or adjuvant therapy until at least four weeks post-surgery. The levels of plasma cytokines, chemokines, and growth factors were simultaneously quantified and profiled using multiplexed immunoassays for eight time points sampled per patient. The immunologic processes are induced immediately after surgery in patients, characterized by a drastic short-term shift in the expression levels of pro-inflammatory and angiogenic molecules and cytokines. A rapid and significant spike in circulating plasma levels of hepatocyte growth factor (HGF), interleukin-6 (IL-6), placental growth factor (PLGF), and matrix metalloproteinase-9 (MMP-9) after surgery was noted. The rise in these molecules was concomitant with a significant drop in transforming growth factor-ß1 (TGF-ß1), platelet-derived growth factor (PDGF-AB/BB), insulin-like growth factor-1 (IGF-1), and monocyte chemoattractant protein-2 (MCP-2). If not earlier, each plasma analyte was normalized to baseline levels within 1-2 weeks after surgery, suggesting that surgical intervention alone was responsible for these effects. The effects of surgical tumor removal on disrupting the pro-inflammatory and angiogenic plasma profiles of cancer patients provide evidence for potentiating malignant progression. Our findings indicate a narrow therapeutic window of opportunity after surgery to prevent disease recurrence.


Assuntos
Neoplasias Colorretais , Neoplasias da Próstata , Masculino , Humanos , Fator de Crescimento Placentário , Recidiva Local de Neoplasia , Quimiocinas , Neoplasias da Próstata/cirurgia , Neoplasias Colorretais/patologia
2.
Cell Signal ; 43: 71-84, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29277445

RESUMO

G protein-coupled receptors (GPCR) can participate in a number of signaling pathways, and this property led to the concept of biased GPCR agonism. Agonists, antagonists and allosteric modulators can bind to GPCRs in different ways, creating unique conformations that differentially modulate signaling through one or more G proteins. A unique neuromedin B (NMBR) GPCR-signaling platform controlling mammalian neuraminidase-1 (Neu1) and matrix metalloproteinase-9 (MMP9) crosstalk has been reported in the activation of the insulin receptor (IR) through the modification of the IR glycosylation. Here, we propose that there exists a biased GPCR agonism as small diffusible molecules in the activation of Neu1-mediated insulin receptor signaling. GPCR agonists bombesin, bradykinin, angiotensin I and angiotensin II significantly and dose-dependently induce Neu1 sialidase activity and IR activation in human IR-expressing rat hepatoma cell lines (HTC-IR), in the absence of insulin. Furthermore, the GPCR agonist-induced Neu1 sialidase activity could be specifically blocked by the NMBR inhibitor, BIM-23127. Protein expression analyses showed that these GPCR agonists significantly induced phosphorylation of IRß and insulin receptor substrate-1 (IRS1). Among these, angiotensin II was the most potent GPCR agonist capable of promoting IRß phosphorylation in HTC-IR cells. Interestingly, treatment with BIM-23127 and Neu1 inhibitor oseltamivir phosphate were able to block GPCR agonist-induced IR activation in HTC cells in vitro. Additionally, we found that angiotensin II receptor (type I) exists in a multimeric receptor complex with Neu1, IRß and NMBR in naïve (unstimulated) and stimulated HTC-IR cells with insulin, bradykinin, angiotensin I and angiotensin II. This complex suggests a molecular link regulating the interaction and signaling mechanism between these molecules on the cell surface. These findings uncover a biased GPCR agonist-induced IR transactivation signaling axis, mediated by Neu1 sialidase and the modification of insulin receptor glycosylation.


Assuntos
Metaloproteinase 9 da Matriz/metabolismo , Neuraminidase/metabolismo , Receptor de Insulina/genética , Receptores Acoplados a Proteínas G/agonistas , Transdução de Sinais , Ativação Transcricional/genética , Animais , Linhagem Celular , Humanos , Insulina/farmacologia , Neurocinina B/análogos & derivados , Neurocinina B/antagonistas & inibidores , Neurocinina B/metabolismo , Oseltamivir/farmacologia , Peptídeos Cíclicos/farmacologia , Fosforilação/efeitos dos fármacos , Subunidades Proteicas/metabolismo , Ratos , Receptores Acoplados a Proteínas G/metabolismo , Ativação Transcricional/efeitos dos fármacos
3.
Onco Targets Ther ; 10: 2427-2447, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28496342

RESUMO

BACKGROUND: Prostaspheres-based three dimensional (3D) culture models have provided insight into prostate cancer (PCa) biology, highlighting the importance of cell-cell interactions and the extracellular matrix (EMC) in the tumor microenvironment. Although these 3D classical spheroid platforms provide a significant advance over 2D models mimicking in vivo tumors, the limitations involve no control of assembly and structure with only limited spatial or glandular organization. Here, matrix-free prostaspheres from human metastatic prostate carcinoma PC3 and DU145 cell lines and their respective gemcitabine resistant (GemR) variants were generated by using cyclic Arg-Gly-Asp-D-Phe-Lys peptide modified with 4-carboxybutyl-triphenylphosphonium bromide (cyclo-RGDfK(TPP)). MATERIALS AND METHODS: Microscopic imaging, immunocytochemistry (ICC), flow cytometry, sialidase, and WST-1 cell viability assays were used to evaluate the formation of multicellular tumor spheroid (MCTS), cell survival, morphologic changes, and expression levels of α2,6 and α2,3 sialic acid (SA) and E- and N-cadherin in DU145, PC3, and their GemR variants. RESULTS: By using the cyclo-RGDfK(TPP) peptide platform in a dose- and time-dependent manner, both DU145 and DU145GemR cells formed small MCTS. In contrast, PC3 and PC3GemR cells formed irregular multicellular aggregates at all concentrations of cyclo-RGDfK(TPP) peptide, even after 6 days of incubation. ICC and flow cytometry results revealed that DU145 cells expressed higher amounts of E-cadherin but lower N-cadherin compared with PC3 cells. By using Maackia amurensis (α2,3-SA-specific MAL-II) and Sambucus nigra (α2,6-SA specific SNA) lectin-based cytochemistry staining and flow cytometry, it was found that DU145 and DU145GemR cells expressed 5 times more α2,6-SA than α2,3-SA on the cell surface. PC3 cells expressed 4 times more α2,3-SA than α2,6-SA, and the PC3GemR cells showed 1.4 times higher α2,6-SA than α2,3-SA. MCTS volume was dose-dependently reduced following pretreatment with α2,6-SA-specific neuraminidase (Vibrio cholerae). Oseltamivir phosphate enhanced cell aggregation and compaction of 3D MCTS formed with PC3 cells. CONCLUSION: The relative levels of specific sialoglycan structures on the cell surface correlate with the ability of PCa cells to form avascular multicellular prostaspheres.

4.
Artigo em Inglês | MEDLINE | ID: mdl-28280388

RESUMO

One of the primary challenges in developing effective therapies for malignant tumors is the specific targeting of a heterogeneous cancer cell population within the tumor. The cancerous tumor is made up of a variety of distinct cells with specialized receptors and proteins that could potentially be viable targets for drugs. In addition, the diverse signals from the local microenvironment may also contribute to the induction of tumor growth and metastasis. Collectively, these factors must be strategically studied and targeted in order to develop an effective treatment protocol. Targeted multimodal approaches need to be strategically studied in order to develop a treatment protocol that is successful in controlling tumor growth and preventing metastatic burden. Breast cancer, in particular, presents a unique problem because of the variety of subtypes of cancer that can arise and the multiple drug targets that could be exploited. For example, the tumor stage and subtypes often dictate the appropriate treatment regimen. Alternate multimodal therapies should consider the importance of time-dependent drug administration, as well as targeting the local and systemic tumor environment. Many reviews and papers have briefly touched on the clinical implications of this cellular heterogeneity; however, there has been very little discussion on the development of study models that reflect this diversity and on multimodal therapies that could target these subpopulations. Here, we summarize the current understanding of the origins of intratumoral heterogeneity in breast cancer subtypes, and its implications for tumor progression, metastatic potential, and treatment regimens. We also discuss the advantages and disadvantages of utilizing specific breast cancer models for research, including in vitro monolayer systems and three-dimensional mammospheres, as well as in vivo murine models that may have the capacity to encompass this heterogeneity. Lastly, we summarize some of the current advancements in the development of multitarget therapeutics that have shown promising results in clinical and preclinical studies when used alone or in combination with traditional regimens of surgery, chemotherapy, and/or radiation.

5.
Oncotarget ; 7(40): 66119-66134, 2016 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-27608845

RESUMO

Multicellular tumor spheroids (MTS) have been at the forefront of cancer research, designed to mimic tumor-like developmental patterns in vitro. Tumor growth in vivo is highly influenced by aberrant cell surface-specific sialoglycan structures on glycoproteins. Aberrant sialoglycan patterns that facilitate MTS formation are not well defined. Matrix-free spheroids from breast MCF-7 and pancreatic PANC1 cancer cell lines and their respective tamoxifen (TMX) and gemcitabine (Gem) resistant variants were generated using the RGD platform of cyclic Arg-Gly-Asp-D-Phe-Lys peptide modified with 4-carboxybutyl-triphenylphosphonium bromide (cyclo-RGDfK (TPP)). MCF-7 and MCF-7 TMX cells formed tight spheroids both in the classical agarose-and RGD-based platforms while all PANC1 cells formed loose aggregates. Using lectin histochemistry staining, sialidase assay, neuraminidase (Vibrio cholerae) and oseltamivir phosphate (OP) neuraminidase inhibitor treatments, MCF-7 and PANC1 cells and their drug-resistant variants expressed different sialic acid (SA) content on their cell surfaces. α-2,3- and α-2,6-sialic acid surface residues facilitated spheroid formation under cyclo-RGDfK(TPP)-induced self-assembly. Pretreatment with α-2,3- SA specific Maackia amurensis (MAL-II) lectin, α-2,6-SA specific Sambucus nigra (SNA) lectin, and exogenous α-2,6-SA specific neuraminidase (Vibrio cholerae) dose-dependently reduced spheroid volume. OP enhanced cell aggregation and compaction forming spheroids. PANC1 and MDA-MB231 xenograft tumors from untreated and OP-treated RAGxCγ double mutant mice expressed significantly higher levels of α-2,3- SA over α-2,6-SA. MCF-7 spheroids also expressed a high α-2,3-SA to α-2,6-SA ratio. These results suggest that the relative levels of specific sialoglycan structures on the cell surface correlate with the ability of cancer cells to form avascular multicellular tumor spheroids and in vivo xenograft tumors.


Assuntos
Neoplasias da Mama/patologia , Glicoproteínas/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Neoplasias Pancreáticas/patologia , Peptídeos Cíclicos/farmacologia , Esferoides Celulares/efeitos dos fármacos , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Adesão Celular , Movimento Celular , Proliferação de Células , Feminino , Humanos , Camundongos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Oncotarget ; 7(26): 40860-40881, 2016 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-27029067

RESUMO

Several of the growth factors and their receptor tyrosine kinases (RTK) such as epidermal growth factor (EGF), platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), nerve growth factor (NGF) and insulin are promising candidate targets for cancer therapy. Indeed, tyrosine kinase inhibitors (TKI) have been developed to target these growth factors and their receptors, and have demonstrated dramatic initial responses in cancer therapy. Yet, most patients ultimately develop TKI drug resistance and relapse. It is essential in the clinical setting that the targeted therapies are to circumvent multistage tumorigenesis, including genetic mutations at the different growth factor receptors, tumor neovascularization, chemoresistance of tumors, immune-mediated tumorigenesis and the development of tissue invasion and metastasis. Here, we identify a novel receptor signaling platform linked to EGF, NGF, insulin and TOLL-like receptor (TLR) activations, all of which are known to play major roles in tumorigenesis. The importance of these findings signify an innovative and promising entirely new targeted therapy for cancer. The role of mammalian neuraminidase-1 (Neu1) in complex with matrix metalloproteinase-9 and G protein-coupled receptor tethered to RTKs and TLRs is identified as a major target in multistage tumorigenesis. Evidence exposing the link connecting growth factor-binding and immune-mediated tumorigenesis to this novel receptor-signaling paradigm will be reviewed in its current relationship to cancer.


Assuntos
Carcinogênese/metabolismo , Neoplasias/metabolismo , Neuraminidase/metabolismo , Animais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Sobrevivência Celular , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos , Ativação Enzimática , Receptores ErbB/metabolismo , Feminino , Humanos , Macrófagos/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Mutação , Metástase Neoplásica , Oseltamivir/farmacologia , Neoplasias Ovarianas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Transdução de Sinais
7.
Drug Des Devel Ther ; 9: 4573-86, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26309402

RESUMO

Poly (lactic-co-glycolic acid) (PLGA) copolymers have been extensively used in cancer research. PLGA can be chemically engineered for conjugation or encapsulation of drugs in a particle formulation. We reported that oseltamivir phosphate (OP) treatment of human pancreatic tumor-bearing mice disrupted the tumor vasculature with daily injections. Here, the controlled release of OP from a biodegradable PLGA cylinder (PLGA-OP) implanted at tumor site was investigated for its role in limiting tumor neovascularization, growth, and metastasis. PLGA-OP cylinders over 30 days in vitro indicated 20%-25% release profiles within 48 hours followed by a continuous metronomic low dose release of 30%-50% OP for an additional 16 days. All OP was released by day 30. Surgically implanted PLGA-OP containing 20 mg OP and blank PLGA cylinders at the tumor site of heterotopic xenografts of human pancreatic PANC1 tumors in RAGxCγ double mutant mice impeded tumor neovascularization, growth rate, and spread to the liver and lungs compared with the untreated cohort. Xenograft tumors from PLGA and PLGA-OP-treated cohorts expressed significant higher levels of human E-cadherin with concomitant reduced N-cadherin and host CD31(+) endothelial cells compared with the untreated cohort. These results clearly indicate that OP delivered from PLGA cylinders surgically implanted at the site of the solid tumor show promise as an effective treatment therapy for cancer.


Assuntos
Inibidores da Angiogênese/administração & dosagem , Carcinoma/tratamento farmacológico , Portadores de Fármacos , Neoplasias Hepáticas/prevenção & controle , Neoplasias Pulmonares/prevenção & controle , Neovascularização Patológica , Oseltamivir/administração & dosagem , Neoplasias Pancreáticas/tratamento farmacológico , Polietilenoglicóis/química , Implantes Absorvíveis , Inibidores da Angiogênese/química , Animais , Antígenos CD/metabolismo , Caderinas/metabolismo , Carcinoma/irrigação sanguínea , Carcinoma/metabolismo , Carcinoma/secundário , Linhagem Celular Tumoral , Química Farmacêutica , Implantes de Medicamento , Subunidade gama Comum de Receptores de Interleucina/deficiência , Subunidade gama Comum de Receptores de Interleucina/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Camundongos Endogâmicos NOD , Camundongos Knockout , Oseltamivir/química , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Solubilidade , Fatores de Tempo , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Artigo em Inglês | MEDLINE | ID: mdl-25525387

RESUMO

BACKGROUND: Triple-negative breast cancers (TNBCs) lack the estrogen, progesterone, and epidermal growth factor (EGF) receptor-2 (HER2/neu) receptors. Patients with TNBC have typical high grading, more frequent relapses, and exhibit poorer outcomes or prognosis compared with the other subtypes of breast cancers. Currently, there are no targeted therapies that are effective for TNBC. Preclinical antitumor activity of oseltamivir phosphate (OP) therapy was investigated to identify its role in tumor neovascularization, growth, invasiveness, and long-term survival in a mouse model of human TNBC. METHODS: Live cell sialidase, water soluble tetrazolium, WST-1 cell viability, and immunohistochemistry assays were used to evaluate sialidase activity, cell survival, and the expression levels of tumor E-cadherin, N-cadherin, and host endothelial CD31+/PECAM-1 cells in archived paraffin-embedded TNBC MDA-MB-231 tumors grown in RAGxCγ double mutant mice. RESULTS: OP, anti-Neu1 antibodies, and matrix metalloproteinase-9-specific inhibitor blocked Neu1 activity associated with EGF-stimulated TNBC MDA-MB-231 cells. OP treatment of MDA-MB-231 and MCF-7 cells and their long-term tamoxifen-resistant clones reproducibly and dose-dependently reduced the sialidase activity associated with EGF-stimulated live cells and the cell viability after 72 hours of incubation. Combination of 1 µM cisplatin, 5-FU, paclitaxel, gemcitabine, or tamoxifen with OP dosages ≥300 µg/mL significantly reduced cell viability at 24, 48, and 72 hours when compared to the chemodrug alone. Heterotopic xenografts of MDA-MB-231 tumors developed robust and bloody tumor vascularization in RAG2xCγ double mutant mice. OP treatment at 30 mg/kg daily intraperitoneally reduced tumor vascularization and growth rate as well as significantly reduced tumor weight and spread to the lungs compared with the untreated cohorts. OP treatment at 50 mg/kg completely ablated tumor vascularization, tumor growth and spread to the lungs, with significant long-term survival at day 180 postimplantation, tumor shrinking, and no relapses after 56 days off-drug. OP 30 mg/kg cohort tumors expressed significantly reduced levels of human N-cadherins and host CD31+ endothelial cells with concomitant significant expression of E-cadherins compared to the untreated cohorts. CONCLUSION: OP monotherapy may be the effective treatment therapy for TNBC.

9.
Clin Transl Med ; 3(1): 28, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26932374

RESUMO

BACKGROUND: Snail, a transcriptional factor and repressor of E-cadherin is well known for its role in cellular invasion. It can regulate epithelial to mesenchymal transition (EMT) during embryonic development and in epithelial cells. Snail also mediates tumor progression and metastases. Silencing of Snail and its associate member Slug in human A2780 ovarian epithelial carcinoma cell line was investigated to identify its role in tumor neovascularization. METHODS: Live cell sialidase, WST-1 cell viability and immunohistochemistry assays were used to evaluate sialidase activity, cell survival and the expression levels of tumor E-cadherin, N-cadherin, VE-cadherin, and host endothelial CD31+(PECAM-1) cells in archived paraffin-embedded ovarian A2780, A2780 Snail shRNA GIPZ lentiviral knockdown (KD) and A2780 Slug shRNA GIPZ lentiviral KD tumors grown in RAGxCγ double mutant mice. RESULTS: Oseltamivir phosphate (OP), anti-Neu1 antibodies and MMP-9 specific inhibitor blocked Neu1 activity associated with epidermal growth factor (EGF) stimulated A2780 ovarian epithelial carcinoma cells. Silencing Snail in A2780 cells abrogated the Neu1 activity following EGF stimulation of the cells compared to A2780 and A2780 Slug KD cells. OP treatment of A2780 and cisplatin-resistant A2780cis cells reproducibly and dose-dependently abated the cell viability with a LD50 of 7 and 4 µm, respectively, after 48 h of incubation. Heterotopic xenografts of A2780 and A2780 Slug KD tumors developed robust and bloody tumor vascularization in RAG2xCγ double mutant mice. OP treatment at 50 mg/kg daily intraperitoneally did not significantly impede A2780 tumor growth rate but did cause a significant reduction of lung metastases compared with the untreated and OP 30mg/kg cohorts. Silencing Snail in A2780 tumor cells completely abrogated tumor vascularization, tumor growth and spread to the lungs in RAGxCγ double mutant mice. A2780 and A2780 Slug KD tumors expressed high levels of human N- and VE-cadherins, and host CD31+ endothelial cells, while A2780 Snail KD tumors expressed E-cadherin and reduced host CD31+ cells. OP 50mg/kg cohort tumors had reduced numbers of host CD31+ cells compared to a higher expression levels of CD31+ cells in tumors from the untreated control and OP 30mg/kg cohorts. CONCLUSION: Snail transcriptional factor is an important intermediate player in human ovarian tumor neovascularization.

10.
J Clin Invest ; 121(3): 1199-206, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21339645

RESUMO

Obstructive and nonobstructive forms of hydronephrosis (increased diameter of the renal pelvis and calyces) and hydroureter (dilatation of the ureter) are the most frequently detected antenatal abnormalities, yet the underlying molecular mechanisms are largely undefined. Hedgehog (Hh) proteins control tissue patterning and cell differentiation by promoting GLI-dependent transcriptional activation and by inhibiting the processing of GLI3 to a transcriptional repressor. Genetic mutations that generate a truncated GLI3 protein similar in size to the repressor in humans with Pallister-Hall syndrome (PHS; a disorder whose characteristics include renal abnormalities) and hydroureter implicate Hh-dependent signaling in ureter morphogenesis and function. Here, we determined that Hh signaling controls 2 cell populations required for the initiation and transmission of coordinated ureter contractions. Tissue-specific inactivation of the Hh cell surface effector Smoothened (Smo) in the renal pelvic and upper ureteric mesenchyme resulted in nonobstructive hydronephrosis and hydroureter characterized by ureter dyskinesia. Mutant mice had reduced expression of markers of cell populations implicated in the coordination of unidirectional ureter peristalsis (specifically, Kit and hyperpolarization-activation cation-3 channel [Hcn3]), but exhibited normal epithelial and smooth muscle cell differentiation. Kit deficiency in a mouse model of PHS suggested a pathogenic role for GLI3 repressor in Smo-deficient embryos; indeed, genetic inactivation of Gli3 in Smo-deficient mice rescued their hydronephrosis, hydroureter, Kit and Hcn3 expression, and ureter peristalsis. Together, these data demonstrate that Hh signaling controls Kit and Hcn3 expression and ureter peristalsis.


Assuntos
Proteínas Hedgehog/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Mutação , Proteínas do Tecido Nervoso/metabolismo , Ureter/fisiologia , Animais , Membrana Celular/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Deleção de Genes , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização , Camundongos , Fenótipo , Canais de Potássio , Proteínas Proto-Oncogênicas c-kit/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Receptor Smoothened , Fatores de Tempo , Ativação Transcricional , Proteína Gli3 com Dedos de Zinco
11.
PLoS One ; 4(10): e7313, 2009 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-19809516

RESUMO

Truncating GLI3 mutations in Pallister-Hall Syndrome with renal malformation suggests a requirement for Hedgehog signaling during renal development. HH-dependent signaling increases levels of GLI transcriptional activators and decreases processing of GLI3 to a shorter transcriptional repressor. Previously, we showed that Shh-deficiency interrupts early inductive events during renal development in a manner dependent on GLI3 repressor. Here we identify a novel function for GLI3 repressor in controlling nephron number. During renal morphogenesis, HH signaling activity, assayed by expression of Ptc1-lacZ, is localized to ureteric cells of the medulla, but is undetectable in the cortex. Targeted inactivation of Smo, the HH effector, in the ureteric cell lineage causes no detectable abnormality in renal morphogenesis. The functional significance of absent HH signaling activity in cortical ureteric cells was determined by targeted deletion of Ptc1, the SMO inhibitor, in the ureteric cell lineage. Ptc1(-/-UB) mice demonstrate ectopic Ptc1-lacZ expression in ureteric branch tips and renal hypoplasia characterized by reduced kidney size and a paucity of mature and intermediate nephrogenic structures. Ureteric tip cells are remarkable for abnormal morphology and impaired expression of Ret and Wnt11, markers of tip cell differentiation. A finding of renal hypoplasia in Gli3(-/-) mice suggests a pathogenic role for reduced GLI3 repressor in the Ptc1(-/-UB) mice. Indeed, constitutive expression of GLI3 repressor via the Gli3(Delta699) allele in Ptc1(-/-UB) mice restores the normal pattern of HH signaling, and expression of Ret and Wnt11 and rescued the renal phenotype. Thus, GLI3 repressor controls nephron number by regulating ureteric tip cell expression of Wnt11 and Ret.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Rim/embriologia , Rim/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Néfrons/embriologia , Néfrons/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas Proto-Oncogênicas c-ret/metabolismo , Ureter/metabolismo , Proteínas Wnt/metabolismo , Animais , Apoptose , Linhagem da Célula , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Fenótipo , Proteína Gli3 com Dedos de Zinco
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