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[This corrects the article DOI: 10.1371/journal.ppat.1008730.].
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Kaposi's sarcoma (KS), caused by Kaposi's sarcoma-associated herpesvirus (KSHV), is a highly angioproliferative disseminated tumor of endothelial cells commonly found in AIDS patients. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) mediates KSHV-induced cell motility (PLoS Pathog. 2019 Jan 30;15(1):e1007578). However, the role of vIRF1 in KSHV-induced cellular transformation and angiogenesis remains unknown. Here, we show that vIRF1 promotes angiogenesis by upregulating sperm associated antigen 9 (SPAG9) using two in vivo angiogenesis models including the chick chorioallantoic membrane assay (CAM) and the matrigel plug angiogenesis assay in mice. Mechanistically, vIRF1 interacts with transcription factor Lef1 to promote SPAG9 transcription. vIRF1-induced SPAG9 promotes the interaction of mitogen-activated protein kinase kinase 4 (MKK4) with JNK1/2 to increase their phosphorylation, resulting in enhanced VEGFA expression, angiogenesis, cell proliferation and migration. Finally, genetic deletion of ORF-K9 from KSHV genome abolishes KSHV-induced cellular transformation and impairs angiogenesis. Our results reveal that vIRF1 transcriptionally activates SPAG9 expression to promote angiogenesis and tumorigenesis via activating JNK/VEGFA signaling. These novel findings define the mechanism of KSHV induction of the SPAG9/JNK/VEGFA pathway and establish the scientific basis for targeting this pathway for treating KSHV-associated cancers.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Herpesvirus Humano 8/metabolismo , Fatores Reguladores de Interferon/metabolismo , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Proteína Quinase 9 Ativada por Mitógeno/metabolismo , Sarcoma de Kaposi/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteínas Virais/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Transformação Celular Neoplásica , Herpesvirus Humano 8/genética , Interações Hospedeiro-Patógeno , Humanos , Fatores Reguladores de Interferon/genética , Masculino , Camundongos , Proteína Quinase 8 Ativada por Mitógeno/genética , Proteína Quinase 9 Ativada por Mitógeno/genética , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/fisiopatologia , Sarcoma de Kaposi/genética , Sarcoma de Kaposi/fisiopatologia , Sarcoma de Kaposi/virologia , Fator A de Crescimento do Endotélio Vascular/genética , Proteínas Virais/genéticaRESUMO
Kaposi's sarcoma (KS), a highly angiogenic and invasive vascular tumor, is the most common AIDS-associated cancer caused by KS-associated herpesvirus (KSHV) infection. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) contributes to KSHV-induced cell motility (PLoS Pathog. 15:e1007578, 2019). However, the role of vIRF1 in KSHV-induced angiogenesis remains unknown. Here, using two in vivo angiogenesis models including the chick chorioallantoic membrane assay (CAM) and the matrigel plug angiogenesis assay in mice, we show that vIRF1 promotes angiogenesis by upregulating CUB domain (for complement C1r/C1s, Uegf, Bmp1) containing protein 1 (CDCP1). Mechanistically, vIRF1 enhances the expression of transcription factor lymphoid enhancer-binding factor 1 (Lef1) and binds to Lef1 to promote CDCP1 transcription. Meanwhile, vIRF1 degrades metastasis suppressor CD82 through an ubiquitin-proteasome pathway by recruiting E3 ubiquitin ligase AMFR to CD82, which protects CDCP1 from CD82-mediated, palmitoylation-dependent degradation. CDCP1 activates AKT signaling, which is required for vIRF1-induced cell motility but not angiogenesis. Our results illustrate that, by hijacking Lef1 and CD82, vIRF1 upregulates CDCP1 to promote angiogenesis and cell invasion. These novel findings demonstrate the vIRF1 targets multiple cellular proteins and pathways to promote the pathogenesis of KS, which could be attractive therapeutic targets for KSHV-induced malignancies.
Assuntos
Herpesvirus Humano 8/fisiologia , Fatores Reguladores de Interferon/metabolismo , Proteína Kangai-1/metabolismo , Fator 1 de Ligação ao Facilitador Linfoide/metabolismo , Neovascularização Patológica/patologia , Sarcoma de Kaposi/patologia , Proteínas Virais/metabolismo , Animais , Carcinogênese , Movimento Celular , Regulação da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana , Humanos , Fatores Reguladores de Interferon/genética , Proteína Kangai-1/genética , Fator 1 de Ligação ao Facilitador Linfoide/genética , Masculino , Camundongos , Camundongos Nus , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/virologia , Sarcoma de Kaposi/genética , Sarcoma de Kaposi/metabolismo , Sarcoma de Kaposi/virologia , Transdução de Sinais , Ubiquitina-Proteína Ligases , Proteínas Virais/genéticaRESUMO
Kaposi's sarcoma (KS) caused by oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV) is a highly angiogenic and invasive vascular tumor and the most common AIDS-associated cancer. KSHV-encoded viral interleukin-6 (vIL-6) is implicated in the development of KSHV-induced malignancies; however, the mechanisms underlying vIL-6-induced angiogenesis and tumorigenesis remain undefined. Here, we show that vIL-6 promotes angiogenesis, cell proliferation, and invasion by downregulating caveolin 1 (CAV1) that plays a pivotal and versatile role in multiple cancer-associated processes. Mechanistically, vIL-6 signaling led to the phosphorylation and acetylation of STAT3 that targeted DNA methyltransferase 1 (DNMT1) in a sequential manner. Specifically, the vIL-6-induced phosphorylated form of STAT3 transcriptionally activated DNMT1 expression. Furthermore, vIL-6-induced acetylated form of STAT3 interacted with DNMT1 to form a transcription factor complex that bound to and methylated the CAV1 promoter, leading to CAV1 expression silencing. In fact, downregulation of CAV1 expression resulted in the activation of AKT signaling, promoting cell invasion, and growth transformation induced by KSHV. Finally, genetic deletion of vIL-6 from the KSHV genome abolished KSHV-induced cellular transformation and impaired angiogenesis. Our results reveal that vIL-6 epigenetically silences CAV1 expression to promote angiogenesis and tumorigenesis by regulating the formation of STAT3-DNMT1 complex. These novel findings define a mechanism by which KSHV inhibits the CAV1 pathway and establish the scientific basis for targeting this pathway to treat KSHV-associated cancers.