RESUMO
It has previously been reported that antioxidant vitamins can help reduce the risk of vision loss associated with progression to advanced age-related macular degeneration (AMD), a leading cause of visual impairment among the elderly. Nonetheless, how oxidative stress contributes to the development of choroidal neovascularization (CNV) in some AMD patients and geographic atrophy (GA) in others is poorly understood. Here, we provide evidence demonstrating that oxidative stress cooperates with hypoxia to synergistically stimulate the accumulation of hypoxia-inducible factor (HIF)-1α in the retinal pigment epithelium (RPE), resulting in increased expression of the HIF-1-dependent angiogenic mediators that promote CNV. HIF-1 inhibition blocked the expression of these angiogenic mediators and prevented CNV development in an animal model of ocular oxidative stress, demonstrating the pathological role of HIF-1 in response to oxidative stress stimulation in neovascular AMD. While human-induced pluripotent stem cell (hiPSC)-derived RPE monolayers exposed to chemical oxidants resulted in disorganization and disruption of their normal architecture, RPE cells proved remarkably resistant to oxidative stress. Conversely, equivalent doses of chemical oxidants resulted in apoptosis of hiPSC-derived retinal photoreceptors. Pharmacologic inhibition of HIF-1 in the mouse retina enhanced-while HIF-1 augmentation reduced-photoreceptor apoptosis in two mouse models for oxidative stress, consistent with a protective role for HIF-1 in photoreceptors in patients with advanced dry AMD. Collectively, these results suggest that in patients with AMD, increased expression of HIF-1α in RPE exposed to oxidative stress promotes the development of CNV, but inadequate HIF-1α expression in photoreceptors contributes to the development of GA.
Assuntos
Neovascularização de Coroide , Atrofia Geográfica , Degeneração Macular Exsudativa , Camundongos , Animais , Humanos , Idoso , Epitélio Pigmentado da Retina/metabolismo , Fator 1 Induzível por Hipóxia/metabolismo , Inibidores da Angiogênese , Degeneração Macular Exsudativa/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Acuidade Visual , Neovascularização de Coroide/genética , Neovascularização de Coroide/prevenção & controle , Neovascularização de Coroide/metabolismo , Oxidantes/metabolismo , Hipóxia/metabolismoRESUMO
BACKGROUND: Angiopoietin-like 4 is a molecular hallmark that correlates with the growth and metastasis of head and neck squamous cell carcinoma, one of the most prevalent cancers worldwide. However, the molecular mechanisms by which angiopoietin-like 4 promotes head and neck squamous cell carcinoma tumorigenesis are unclear. METHODS: Using well-characterized cell lines of head and neck squamous cell carcinoma development, including human normal oral keratinocytes, dysplastic oral keratinocytes, oral leukoplakia-derived oral keratinocytes, and head and neck squamous cell carcinoma cell lines, HN13, HN6, HN4, HN12, and CAL27, we investigated the signaling pathways upstream and downstream of angiopoietin-like 4-induced head and neck squamous cell carcinoma tumorigenesis. RESULTS: We found that both epidermal growth factor receptor ligands, epithelial growth factor, and amphiregulin led to angiopoietin-like 4 upregulation in normal oral keratinocytes and dysplastic oral keratinocytes and cooperated with the activation of hypoxia-inducible factor-1 in this effect. Interestingly, amphiregulin and angiopoietin-like 4 were increased in dysplastic oral keratinocytes and head and neck squamous cell carcinoma cell lines, and amphiregulin-induced activation of cell proliferation was dependent on angiopoietin-like 4. Although both p38 mitogen-activated protein kinases (p38 MAPK) and protein kinase B (AKT) were activated by angiopoietin-like 4, only pharmacological inhibition of p38 MAPK was sufficient to prevent head and neck squamous cell carcinoma cell proliferation and migration. We further observed that angiopoietin-like 4 promoted the secretion of interleukin 11 (IL-11), interleukin 12 (IL-12), interleukin-1 alpha (IL-1α), vascular endothelial growth factor, platelet-derived growth factor (PDGF), and tumour necrosis factor alpha (TNF-α), cytokines and chemokines previously implicated in head and neck squamous cell carcinoma pathogenesis. CONCLUSION: Our results demonstrate that angiopoietin-like 4 is a downstream effector of amphiregulin and promotes head and neck squamous cell carcinoma development both through direct activation of p38 kinase as well as paracrine mechanisms.
Assuntos
Anfirregulina , Proteína 4 Semelhante a Angiopoietina , Movimento Celular , Proliferação de Células , Neoplasias de Cabeça e Pescoço , Carcinoma de Células Escamosas de Cabeça e Pescoço , Regulação para Cima , Proteínas Quinases p38 Ativadas por Mitógeno , Humanos , Anfirregulina/farmacologia , Anfirregulina/metabolismo , Proliferação de Células/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Movimento Celular/efeitos dos fármacos , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Proteína 4 Semelhante a Angiopoietina/metabolismo , Linhagem Celular Tumoral , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/metabolismo , Transdução de Sinais , Queratinócitos/metabolismo , Queratinócitos/efeitos dos fármacos , Receptores ErbB/metabolismoRESUMO
BACKGROUND: Compelling evidence implicates diabetes-associated hyperglycemia as a promoter of tumor progression in oral potentially malignant disorders (OPMD). Yet, information on hyperglycemia-induced cell signaling networks in oral oncology remains limited. Our group recently reported that glucose-rich conditions significantly enhance oral dysplastic keratinocyte viability and migration through epidermal growth factor receptor (EGFR) activation, a pathway strongly linked to oral carcinogenesis. Here, we investigated the basal metabolic phenotype in these cells and whether specific glucose-responsive EGFR ligands mediate these responses. METHODS: Cell energy phenotype and lactate concentration were evaluated via commercially available assays. EGFR ligands in response to normal (5 mM) or high (20 mM) glucose were analyzed by quantitative real-time PCR, ELISA, and western blotting. Cell viability and migration assays were performed in the presence of pharmacological inhibitors or RNA interference. RESULTS: When compared to normal keratinocytes, basal glycolysis in oral dysplastic keratinocytes was significantly elevated. In highly glycolytic cells, high glucose-activated EGFR increasing viability and migration. Notably, we identified amphiregulin (AREG) as the predominant glucose-induced EGFR ligand. Indeed, enhanced cell migration in response to high glucose was blunted by EGFR inhibitor cetuximab and AREG siRNA. Conversely, AREG treatment under normal glucose conditions significantly increased cell viability, migration, lactate levels, and expression of glycolytic marker pyruvate kinase M2. CONCLUSION: These novel findings point to AREG as a potential high glucose-induced EGFR activating ligand in highly glycolytic oral dysplastic keratinocytes. Future studies are warranted to gain more insight into the role of AREG in hyperglycemia-associated OPMD tumor progression.
Assuntos
Diabetes Mellitus , Hiperglicemia , Neoplasias , Humanos , Anfirregulina/genética , Anfirregulina/metabolismo , Glucose/farmacologia , Glucose/metabolismo , Ligantes , Receptores ErbB/metabolismo , Família de Proteínas EGF/metabolismo , Queratinócitos/metabolismo , Hiperglicemia/complicações , Hiperglicemia/metabolismo , Carcinogênese/metabolismo , Lactatos/metabolismoRESUMO
Diabetic eye disease is the most common cause of severe vision loss in the working-age population in the developed world, and proliferative diabetic retinopathy (PDR) is its most vision-threatening sequela. In PDR, retinal ischemia leads to the up-regulation of angiogenic factors that promote neovascularization. Therapies targeting vascular endothelial growth factor (VEGF) delay the development of neovascularization in some, but not all, diabetic patients, implicating additional factor(s) in PDR pathogenesis. Here we demonstrate that the angiogenic potential of aqueous fluid from PDR patients is independent of VEGF concentration, providing an opportunity to evaluate the contribution of other angiogenic factor(s) to PDR development. We identify angiopoietin-like 4 (ANGPTL4) as a potent angiogenic factor whose expression is up-regulated in hypoxic retinal Müller cells in vitro and the ischemic retina in vivo. Expression of ANGPTL4 was increased in the aqueous and vitreous of PDR patients, independent of VEGF levels, correlated with the presence of diabetic eye disease, and localized to areas of retinal neovascularization. Inhibition of ANGPTL4 expression reduced the angiogenic potential of hypoxic Müller cells; this effect was additive with inhibition of VEGF expression. An ANGPTL4 neutralizing antibody inhibited the angiogenic effect of aqueous fluid from PDR patients, including samples from patients with low VEGF levels or receiving anti-VEGF therapy. Collectively, our results suggest that targeting both ANGPTL4 and VEGF may be necessary for effective treatment or prevention of PDR and provide the foundation for studies evaluating aqueous ANGPTL4 as a biomarker to help guide individualized therapy for diabetic eye disease.
Assuntos
Angiopoietinas/fisiologia , Retinopatia Diabética/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiopoietinas/metabolismo , Retinopatia Diabética/metabolismo , Olho/irrigação sanguínea , Olho/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neovascularização Patológica , Fator A de Crescimento do Endotélio Vascular/sangueRESUMO
G protein-coupled receptors (GPCRs) represent the largest family of cell surface molecules involved in signal transduction. Surprisingly, open reading frames for multiple GPCRs were hijacked in the process of coevolution between Herpesviridae family viruses and their human and mammalian hosts. Virally encoded GPCRs (vGPCRs) evolved as parts of viral genomes, and this evolution allowed the power of host GPCR signaling circuitries to be harnessed in order to ensure viral replicative success. Phylogenetically, vGPCRs are distantly related to human chemokine receptors, although they feature several unique characteristics. Here, we describe the molecular mechanisms underlying vGPCR-mediated viral pathogenesis. These mechanisms include constitutive activity, aberrant coupling to human G proteins and ß-arrestins, binding and activation by human chemokines, and dimerization with other GPCRs expressed in infected cells. The likely structural basis for these molecular events is described for the two closest viral homologs of human GPCRs. This information may aid in the development of novel targeted therapeutic strategies against viral diseases.
Assuntos
Genoma Viral , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Animais , Herpesviridae/genética , Herpesviridae/metabolismo , HumanosRESUMO
Vision loss from ischemic retinopathies commonly results from the accumulation of fluid in the inner retina [macular edema (ME)]. Although the precise events that lead to the development of ME remain under debate, growing evidence supports a role for an ischemia-induced hyperpermeability state regulated, in part, by VEGF. Monthly treatment with anti-VEGF therapies is effective for the treatment of ME but results in a major improvement in vision in a minority of patients, underscoring the need to identify additional therapeutic targets. Using the oxygen-induced retinopathy mouse model for ischemic retinopathy, we provide evidence showing that hypoxic Müller cells promote vascular permeability by stabilizing hypoxia-inducible factor-1α (HIF-1α) and secreting angiogenic cytokines. Blocking HIF-1α translation with digoxin inhibits the promotion of endothelial cell permeability in vitro and retinal edema in vivo. Interestingly, Müller cells require HIF--but not VEGF--to promote vascular permeability, suggesting that other HIF-dependent factors may contribute to the development of ME. Using gene expression analysis, we identify angiopoietin-like 4 (ANGPTL4) as a cytokine up-regulated by HIF-1 in hypoxic Müller cells in vitro and the ischemic inner retina in vivo. ANGPTL4 is critical and sufficient to promote vessel permeability by hypoxic Müller cells. Immunohistochemical analysis of retinal tissue from patients with diabetic eye disease shows that HIF-1α and ANGPTL4 localize to ischemic Müller cells. Our results suggest that ANGPTL4 may play an important role in promoting vessel permeability in ischemic retinopathies and could be an important target for the treatment of ME.
Assuntos
Angiopoietinas/metabolismo , Permeabilidade Capilar , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neurônios Retinianos/metabolismo , Proteína 4 Semelhante a Angiopoietina , Angiopoietinas/genética , Animais , Western Blotting , Hipóxia Celular , Células Cultivadas , Retinopatia Diabética/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Imuno-Histoquímica , Isquemia/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , Neurônios Retinianos/citologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Kaposi's sarcoma (KS) is a vascular neoplasm caused by infection of endothelial or endothelial precursor cells with the Kaposi's sarcoma-associated herpesvirus (KSHV/HHV8). Research efforts have focused on defining the molecular events explaining how KSHV promotes pathological angiogenesis and KS tumor formation. mTOR/HIF-1 is a fundamental pathway driving these processes through the upregulation of angiogenic and inflammatory proteins, including VEGF, ANGPTL4, and ANGPT2. Interestingly, HIF-1 has also been implicated in the upregulation of metabolic genes associated with aerobic glycolysis and the growth of solid tumors. However, whether HIF-1 plays a role in regulating cell metabolism in KS remains unexplored. Here, we show that the HIF-1 metabolic effector, pyruvate kinase 2 (PKM2), is upregulated upon KSHV infection of endothelial cells and is necessary to maintain aerobic glycolysis in infected cells. We further demonstrate that PKM2 regulates KS angiogenic phenotype by acting as a coactivator of HIF-1 and increasing the levels of HIF-1 angiogenic factors, including VEGF. Indeed, inhibition of PKM2 expression blocked endothelial cell migration and differentiation and the angiogenic potential of KSHV-infected cells. We also investigated whether PKM2 regulates the angiogenic dysregulation induced by the KSHV-encoded G protein-coupled receptor (vGPCR), a viral oncogene that promotes Kaposi's sarcomagenesis through the upregulation of HIF angiogenic factors. Interestingly, we found that PKM2 controls vGPCR-induced VEGF paracrine secretion and vGPCR oncogenesis. Our findings provide a molecular mechanism for how HIF-1 dysregulation fuels both angiogenesis and tumor metabolism in KS and support further investigations on therapeutic approaches targeting HIF-1 and PKM2 for KS treatment.
Assuntos
Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glicólise , Herpesvirus Humano 8/metabolismo , Fator 1 Induzível por Hipóxia/metabolismo , Proteínas de Neoplasias/metabolismo , Neovascularização Patológica/metabolismo , Piruvato Quinase/biossíntese , Sarcoma de Kaposi/metabolismo , Regulação para Cima , Células Endoteliais da Veia Umbilical Humana , Humanos , Neovascularização Patológica/patologia , Sarcoma de Kaposi/patologiaRESUMO
The Kaposi's sarcoma-associated herpesvirus (KSHV), the infectious causative agent of Kaposi's sarcoma (KS), encodes a G protein-coupled receptor (vGPCR) implicated in the initiation of KS. Here we demonstrate that Kaposi's sarcomagenesis involves stimulation of tuberin (TSC2) phosphorylation by vGPCR, promoting the activation of mTOR through both direct and paracrine mechanisms. Pharmacologic inhibition of mTOR with rapamycin prevented vGPCR sarcomagenesis, while overactivation of this pathway was sufficient to render endothelial cells oncogenic. Moreover, mice haploinsufficient for TSC2 are predisposed to vascular sarcomas remarkably similar to KS. Collectively, these results implicate mTOR in KS initiation and suggest that the sarcomagenic potential of KSHV may be a direct consequence of the profound sensitivity of endothelial cells to vGPCR dysregulation of the TSC2/mTOR pathway.
Assuntos
Transformação Celular Neoplásica , Células Endoteliais/patologia , Herpesvirus Humano 8/genética , Proteínas Quinases/metabolismo , Receptores de Quimiocinas/fisiologia , Proteínas Supressoras de Tumor/metabolismo , Proteínas Virais/fisiologia , Animais , Linhagem Celular , Proliferação de Células , Humanos , Camundongos , Camundongos Nus , Camundongos Transgênicos , Proteína Oncogênica v-akt/antagonistas & inibidores , Proteína Oncogênica v-akt/metabolismo , Comunicação Parácrina , Fosforilação , Proteínas Quinases/genética , Receptores de Quimiocinas/genética , Sarcoma de Kaposi/patologia , Transdução de Sinais , Sirolimo/farmacologia , Serina-Treonina Quinases TOR , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/genética , Proteínas Virais/genéticaRESUMO
Kaposi's sarcoma (KS) is an enigmatic vascular tumor thought to be a consequence of dysregulated expression of the human herpesvirus-8 (HHV-8 or KSHV)-encoded G protein-coupled receptor (vGPCR). Indeed, transgenic animals expressing vGPCR manifest vascular tumors histologically identical to human KS, with expression of the viral receptor limited to a few cells, suggestive of a paracrine mechanism for vGPCR tumorigenesis. Both human and vGPCR experimental KS lesions are characterized by prominent angiogenesis and vascular permeability attributed to the release of angiogenic molecules, most notably vascular endothelial growth factor. However, the relative contribution of these paracrine mediators to the angiogenic and exudative phenotype of KS lesions remains unclear. Here we show that vGPCR up-regulation of Angiopoietin-like 4 (ANGPTL4) plays a prominent role in promoting the angiogenesis and vessel permeability observed in KS. Indeed, ANGPTL4 expression is a hallmark of vGPCR experimental and human KS lesions. Inhibition of ANGPTL4 effectively blocks vGPCR promotion of the angiogenic switch and vascular leakage in vitro and tumorigenesis in vivo. These observations suggest that ANGPTL4 is a previously unrecognized target for the treatment of patients with KS. As angiogenesis and increased vessel permeability are common themes in all solid tumors, these findings may have a broad impact on our understanding and treatment of cancer.
Assuntos
Angiopoietinas/biossíntese , Permeabilidade Capilar , Neovascularização Patológica , Receptores de Quimiocinas/fisiologia , Sarcoma de Kaposi/fisiopatologia , Proteína 4 Semelhante a Angiopoietina , Angiopoietinas/genética , Linhagem Celular , Interações Hospedeiro-Patógeno , Humanos , Comunicação Parácrina , Fator A de Crescimento do Endotélio VascularRESUMO
OBJECTIVES: The molecular mechanisms whereby angiopoietin-like 4 (ANGPTL4), a pluripotent protein implicated in cancer development, contributes to head and neck squamous cell carcinoma (HNSCC) growth and dissemination are unclear. MATERIALS AND METHODS: We investigated ANGPTL4 expression in human normal oral keratinocytes (NOKs), dysplastic oral keratinocytes (DOKs), oral leukoplakia cells (LEUK1), and HNSCC cell lines, as well as in tissue biopsies from patients with oral dysplasia, and primary and metastatic HNSCC. We further examined the contribution of ANGPTL4 cancer progression in an HNSCC orthotopic floor-of mouth tumor model and the signaling pathways linking ANGPTL4 to cancer cell migration. RESULTS: ANGPTL4 expression was upregulated in premalignant DOKs and HNSCC cell lines compared to NOKs and was increased in tissue biopsies from patients with oral dysplasia, as well as in primary and metastatic HNSCC. We also observed that downregulation of ANGPTL4 expression inhibited primary and metastatic cancer growth in an HNSCC orthotopic tumor model. Interestingly, ANGPTL4 binding to the neuropilin1 (NRP1) receptor led to phosphorylation of the focal adhesion protein, paxillin (PXN), and tumor cell migration; this was dependent on the tyrosine kinase ABL1. Treatment with the ABL1 inhibitor, dasatinib and small interfering RNA silencing of NRP1 or ABL1 expression blocked PXN phosphorylation and tumor cell migration. CONCLUSION: Our findings suggest an early, sustained, and angiogenesis-independent autocrine role for ANGPTL4 in HNSCC progression and expose ANGPTL4/NRP1/ABL1/PXN as an early molecular marker and vulnerable target for the prevention of HNSCC growth and metastasis.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Humanos , Angiopoietinas/genética , Angiopoietinas/metabolismo , Carcinoma de Células Escamosas/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Neuropilina-1/metabolismo , Paxilina/metabolismo , Carcinoma de Células Escamosas de Cabeça e PescoçoRESUMO
BACKGROUNDStudies assessing the efficacy of therapies for neovascular age-related macular degeneration (nvAMD) have demonstrated that aflibercept may have a longer treatment interval than its less-expensive alternative, bevacizumab. However, whether this benefit justifies the additional cost of aflibercept remains under debate. We have recently reported that a treat-and-extend-pause/monitor approach can be used to successfully wean 31% of patients with nvAMD off anti-VEGF therapy. Here, we examined whether the choice of therapy influences the outcomes of this approach.METHODSIn this retrospective analysis, 122 eyes of 106 patients with nvAMD underwent 3 consecutive monthly injections with either aflibercept (n = 70) or bevacizumab (n = 52), followed by a treat-and-extend protocol, in which the decision to extend the interval between treatments was based on visual acuity, clinical exam, and the presence or absence of fluid on optical coherence tomography. Eyes that remained stable 12 weeks from their prior treatment were given a 6-week trial of holding further treatment, followed by quarterly monitoring. Treatment was resumed for worsening vision, clinical exam, or optical coherence tomography findings.RESULTSAt the end of 1 year, eyes receiving bevacizumab had similar vision but required more injections (8.7 ± 0.3 treatments vs. 7.2 ± 0.3 treatments) compared with eyes receiving aflibercept. However, eyes treated with aflibercept were almost 3 times more likely to be weaned off treatment (43% vs. 15%) compared with eyes treated with bevacizumab at the end of 1 year.CONCLUSIONThese observations expose an advantage of aflibercept over bevacizumab and have important clinical implications for the selection of therapy for patients with nvAMD.FUNDINGThis work was supported by the National Eye Institute, NIH grants R01EY029750 and R01EY025705, Research to Prevent Blindness, the Alcon Young Investigator Award from the Alcon Research Institute, and the Branna and Irving Sisenwein Professorship in Ophthalmology.
Assuntos
Inibidores da Angiogênese , Degeneração Macular , Humanos , Bevacizumab/uso terapêutico , Inibidores da Angiogênese/uso terapêutico , Ranibizumab/efeitos adversos , Estudos Retrospectivos , Proteínas Recombinantes de Fusão/uso terapêutico , Degeneração Macular/tratamento farmacológico , Resultado do Tratamento , SeguimentosRESUMO
Tight glycemic control (TGC), the cornerstone of diabetic management, reduces the incidence and progression of diabetic microvascular disease. However, TGC can also lead to transient episodes of hypoglycemia, which have been associated with adverse outcomes in patients with diabetes. Here, we demonstrate that low glucose levels result in hypoxia-inducible factor (HIF)-1-dependent expression of the glucose transporter, Glut1, in retinal cells. Enhanced nuclear accumulation of HIF-1α was independent of its canonical post-translational stabilization but instead dependent on stimulation of its translation and nuclear localization. In the presence of hypoxia, this physiologic response to low glucose resulted in a marked increase in the secretion of the HIF-dependent vasoactive mediators that promote diabetic retinopathy. Our results provide a molecular explanation for how early glucose control, as well as glycemic variability (i.e., oscillating serum glucose levels), contributes to diabetic eye disease. These observations have important implications for optimizing glucose management in patients with diabetes.
Assuntos
Diabetes Mellitus , Retinopatia Diabética , Hipoglicemia , Humanos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Retinopatia Diabética/metabolismo , Glucose/metabolismo , Hipoglicemia/complicações , Hipóxia , Subunidade alfa do Fator 1 Induzível por HipóxiaRESUMO
Many patients with diabetic eye disease respond inadequately to anti-VEGF therapies, implicating additional vasoactive mediators in its pathogenesis. We demonstrate that levels of angiogenic proteins regulated by HIF-1 and -2 remain elevated in the eyes of people with diabetes despite treatment with anti-VEGF therapy. Conversely, by inhibiting HIFs, we normalized the expression of multiple vasoactive mediators in mouse models of diabetic eye disease. Accumulation of HIFs and HIF-regulated vasoactive mediators in hyperglycemic animals was observed in the absence of tissue hypoxia, suggesting that targeting HIFs may be an effective early treatment for diabetic retinopathy. However, while the HIF inhibitor acriflavine prevented retinal vascular hyperpermeability in diabetic mice for several months following a single intraocular injection, accumulation of acriflavine in the retina resulted in retinal toxicity over time, raising concerns for its use in patients. Conversely, 32-134D, a recently developed HIF inhibitor structurally unrelated to acriflavine, was not toxic to the retina, yet effectively inhibited HIF accumulation and normalized HIF-regulated gene expression in mice and in human retinal organoids. Intraocular administration of 32-134D prevented retinal neovascularization and vascular hyperpermeability in mice. These results provide the foundation for clinical studies assessing 32-134D for the treatment of patients with diabetic eye disease.
Assuntos
Diabetes Mellitus Experimental , Retinopatia Diabética , Neovascularização Retiniana , Humanos , Camundongos , Animais , Acriflavina/metabolismo , Acriflavina/farmacologia , Acriflavina/uso terapêutico , Diabetes Mellitus Experimental/metabolismo , Retina/metabolismo , Neovascularização Retiniana/metabolismo , Retinopatia Diabética/tratamento farmacológico , Retinopatia Diabética/genética , Retinopatia Diabética/metabolismo , Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismoRESUMO
The Kaposi's sarcoma herpesvirus (KSHV) has been identified as the etiologic agent of Kaposi's sarcoma (KS), but initial events leading to KS development remain unclear. Characterization of the KSHV genome reveals the presence of numerous potential oncogenes. To address their contribution to the initiation of the endothelial cell-derived KS tumor, we developed a novel transgenic mouse that enabled endothelial cell-specific infection in vivo using virus expressing candidate KSHV oncogenes. Here we show that transduction of one gene, vGPCR, was sufficient to induce angioproliferative tumors that strikingly resembled human KS. Endothelial cells expressing vGPCR were further able to promote tumor formation by cells expressing KSHV latent genes, suggestive of a cooperative role among viral genes in the promotion of Kaposi's sarcomagenesis.
Assuntos
Transformação Celular Neoplásica , Herpesvirus Humano 8/genética , Proteínas Proto-Oncogênicas , Receptores de Quimiocinas/metabolismo , Sarcoma de Kaposi/virologia , Proteínas Virais/metabolismo , Animais , Vírus da Leucose Aviária/genética , Células Cultivadas , Endotélio Vascular/fisiologia , Endotélio Vascular/ultraestrutura , Endotélio Vascular/virologia , Engenharia Genética/métodos , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Microscopia Eletrônica , Proteínas de Neoplasias/genética , Regiões Promotoras Genéticas , Sarcoma de Kaposi/genética , Sarcoma de Kaposi/ultraestrutura , Transdução GenéticaRESUMO
For patients with proliferative diabetic retinopathy (PDR) who do not respond adequately to pan-retinal laser photocoagulation (PRP) or anti-vascular endothelial growth factor (VEGF) therapies, we hypothesized that vascular cells within neovascular tissue secrete autocrine/paracrine angiogenic factors that promote disease progression. To identify these factors, we performed multiplex ELISA angiogenesis arrays on aqueous fluid from PDR patients who responded inadequately to anti-VEGF therapy and/or PRP and identified plasminogen activator inhibitor-1 (PAI-1). PAI-1 expression was increased in vitreous biopsies and neovascular tissue from PDR eyes, limited to retinal vascular cells, regulated by the transcription factor hypoxia-inducible factor (HIF)-2α, and necessary and sufficient to stimulate angiogenesis. Using a pharmacologic inhibitor of HIF-2α (PT-2385) or nanoparticle-mediated RNA interference targeting Pai1, we demonstrate that the HIF-2α/PAI-1 axis is necessary for the development of retinal neovascularization in mice. These results suggest that targeting HIF-2α/PAI-1 will be an effective adjunct therapy for the treatment of PDR patients.
Assuntos
Diabetes Mellitus , Retinopatia Diabética , Neovascularização Retiniana , Indutores da Angiogênese/uso terapêutico , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Retinopatia Diabética/tratamento farmacológico , Retinopatia Diabética/etiologia , Retinopatia Diabética/metabolismo , Humanos , Camundongos , Neovascularização Patológica , Inibidor 1 de Ativador de Plasminogênio/genética , Neovascularização Retiniana/etiologia , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Most patients with neovascular age-related macular degeneration (nvAMD), the leading cause of severe vision loss in elderly US citizens, respond inadequately to current therapies targeting a single angiogenic mediator, vascular endothelial growth factor (VEGF). Here, we report that aqueous fluid levels of a second vasoactive mediator, angiopoietin-like 4 (ANGPTL4), can help predict the response of patients with nvAMD to anti-VEGF therapies. ANGPTL4 expression was higher in patients who required monthly treatment with anti-VEGF therapies compared with patients who could be effectively treated with less-frequent injections. We further demonstrate that ANGPTL4 acts synergistically with VEGF to promote the growth and leakage of choroidal neovascular (CNV) lesions in mice. Targeting ANGPTL4 expression was as effective as targeting VEGF expression for treating CNV in mice, while simultaneously targeting both was more effective than targeting either factor alone. To help translate these findings to patients, we used a soluble receptor that binds to both VEGF and ANGPTL4 and effectively inhibited the development of CNV lesions in mice. Our findings provide an assay that can help predict the response of patients with nvAMD to anti-VEGF monotherapy and suggest that therapies targeting both ANGPTL4 and VEGF will be a more effective approach for the treatment of this blinding disease.
Assuntos
Neovascularização de Coroide , Degeneração Macular , Proteína 4 Semelhante a Angiopoietina , Animais , Humor Aquoso/metabolismo , Neovascularização de Coroide/tratamento farmacológico , Degeneração Macular/tratamento farmacológico , Degeneração Macular/metabolismo , Camundongos , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
BackgroundTo reduce the treatment burden for patients with neovascular age-related macular degeneration (nvAMD), emerging therapies targeting vascular endothelial growth factor (VEGF) are being designed to extend the interval between treatments, thereby minimizing the number of intraocular injections. However, which patients will benefit from longer-acting agents is not clear.MethodsEyes with nvAMD (n = 122) underwent 3 consecutive monthly injections with currently available anti-VEGF therapies, followed by a treat-and-extend protocol. Patients who remained quiescent 12 weeks from their prior treatment entered a treatment pause and were switched to pro re nata (PRN) treatment (based on vision, clinical exam, and/or imaging studies). Proteomic analysis was performed on aqueous fluid to identify proteins that correlate with patients' response to treatment.ResultsAt the end of 1 year, 38 of 122 eyes (31%) entered a treatment pause (≥30 weeks). Conversely, 21 of 122 eyes (17%) failed extension and required monthly treatment at the end of year 1. Proteomic analysis of aqueous fluid identified proteins that correlated with patients' response to treatment, including proteins previously implicated in AMD pathogenesis. Interestingly, apolipoprotein-B100 (ApoB100), a principal component of drusen implicated in the progression of nonneovascular AMD, was increased in treated patients who required less frequent injections. ApoB100 expression was higher in AMD eyes compared with controls but was lower in eyes that develop choroidal neovascularization (CNV), consistent with a protective role. Accordingly, mice overexpressing ApoB100 were partially protected from laser-induced CNV.FundingThis work was supported by the National Eye Institute, National Institutes of Health grants R01EY029750, R01EY025705, and R01 EY27961; the Research to Prevent Blindness, Inc.; the Alcon Research Institute; and Johns Hopkins University through the Robert Bond Welch and Branna and Irving Sisenwein professorships in ophthalmology.ConclusionAqueous biomarkers could help identify patients with nvAMD who may not require or benefit from long-term treatment with anti-VEGF therapy.
Assuntos
Inibidores da Angiogênese/administração & dosagem , Apolipoproteína B-100/metabolismo , Neovascularização de Coroide , Proteínas do Olho/metabolismo , Degeneração Macular , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Idoso , Idoso de 80 Anos ou mais , Animais , Neovascularização de Coroide/tratamento farmacológico , Neovascularização de Coroide/metabolismo , Feminino , Humanos , Degeneração Macular/tratamento farmacológico , Degeneração Macular/metabolismo , Masculino , Camundongos , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Importance: Ten percent of the Medicare Part B budget is spent on aflibercept, used to treat a myriad of ocular neovascular diseases. A substantial portion of these costs can be attributed to a few hundred ophthalmologists, raising concerns regarding the influence of pharmaceutical companies on the choice of medication by a relatively small group of clinicians. One approach to protect patients' health care interests is to include them in deliberations on the choice of therapy for their eye disease. Objective: To examine factors associated with patients' choice between an effective and less expensive off-label drug or a more effective, but also more expensive, US Food and Drug Administration (FDA)-approved drug. Design, Setting, and Participants: This retrospective cohort analysis used data from the satellite office of a tertiary referral center from August 2, 2013, to April 9, 2018. Insured patients initiating treatment with anti-vascular endothelial growth factor were included in the analysis. Data were analyzed from March 26, 2018, to June 10, 2020. Interventions: Patients were asked to choose between bevacizumab (approximately $100 per dose), a chemotherapy that is effective, but not FDA approved, for the treatment of ocular vascular disease, or aflibercept (approximately $2000 per dose), an FDA-approved drug for ocular vascular disease that may be more effective than bevacizumab in some patients. Independent of this choice, patients were separately asked by a study coordinator to participate in an invasive clinical study for which they would not be compensated, there was a small risk for an adverse event, and they would not personally benefit from participating (a surrogate marker for altruism). Main Outcomes and Measures: Factors associated with patients' choice of medication, including age, sex, ocular disease, race, and participation in an invasive clinical study. Results: A total of 189 patients were included in the analysis (106 women [56%]; mean [SEM] age, 74.6 [0.8] years). Despite being told that it may not be as effective as aflibercept, 100 patients (53%) selected bevacizumab for their own eye care. An act of altruism (ie, participation in an invasive clinical study) when the patient was making a choice between the 2 drugs was associated with a patient's choice of bevacizumab (odds ratio [OR], 7.03; 95% CI, 2.27-21.80; P < .001); the OR for selecting bevacizumab for patients who never agreed to participate in the clinical study was 0.45 (95% CI, 0.25-0.83; P = .001). Age (OR, 1.00; 95% CI, 0.97-1.03; P = .86), race (OR, 0.70; 95% CI, 0.41-1.22; P = .21), sex (OR, 0.72; 95% CI, 0.39-1.35; P = .31), presence of diabetes (OR, 1.52; 95% CI, 0.59-3.93; P = .39), and type of eye disease (OR, 0.56; 95% CI, 0.30-1.04; P = .07) were not associated with choice of therapy. Conclusions and Relevance: These findings suggest that clinicians must consider the ethical implications of the influence of altruism when patients participate in the decision between cost-effective vs the most effective medicines for their own health care.
Assuntos
Altruísmo , Inibidores da Angiogênese/economia , Bevacizumab/economia , Comportamento de Escolha , Tomada de Decisões , Oftalmopatias/tratamento farmacológico , Participação do Paciente , Proteínas Recombinantes de Fusão/economia , Negro ou Afro-Americano , Idoso , Inibidores da Angiogênese/uso terapêutico , Asiático , Bevacizumab/uso terapêutico , Estudos de Coortes , Análise Custo-Benefício , Retinopatia Diabética/tratamento farmacológico , Custos de Medicamentos , Feminino , Humanos , Degeneração Macular/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Neovascularização Patológica/tratamento farmacológico , Razão de Chances , Uso Off-Label , Receptores de Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Proteínas Recombinantes de Fusão/uso terapêutico , Oclusão da Veia Retiniana/tratamento farmacológico , Estudos Retrospectivos , Resultado do Tratamento , Acuidade Visual , População BrancaRESUMO
A low-shrinkage-stress (LSS), antibacterial and remineralizing nanocomposite was recently developed; however, validation of its long-term antibacterial potency in modulating human salivary-derived biofilm is an unmet need. This study aimed to evaluate the antibacterial effect of the bioactive LSS composite before and after aging in acidic solution for 90 days using a multi-species biofilm model, and to evaluate its cytotoxicity. The LSS composite consisted of urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE), 3% dimethylaminohexadecyl methacrylate (DMAHDM) and 20% nanoparticles of amorphous calcium phosphate (NACP). Biofilm colony-forming units (CFU), lactic acid production, and confocal laser scanning microscopy (3D biofilm) were evaluated before and after three months of aging. Cytotoxicity was assessed against human gingival fibroblasts (HGF). The new LSS composite presented the lowest biofilm CFU, lactic acid and biofilm biomass, compared to controls (n = 6, p < 0.05). Importantly, the new composite exhibited no significant difference in antibacterial performance before and after 90-day-aging, demonstrating long-term antibacterial activity (p > 0.1). The LSS antibacterial and remineralizing composite presented a low cell viability at original extract that has increased with further dilutions. In conclusion, this study spotlighted that the new bioactive composite not only had a low shrinkage stress, but also down-regulated the growth of oral biofilms, reduced acid production, maintained antibacterial activity after the 90-day-aging, and did not compromise the cytocompatibility.