RESUMEN
Rhabdomyosarcoma (RMS) is an aggressive pediatric soft tissue sarcoma characterized by a very poor prognosis when relapses occur after front-line therapy. Therefore, a major challenge for patients' management remains the identification of markers associated with refractory and progressive disease. In this context, cancer autoantibodies are natural markers of disease onset and progression, useful to unveil novel therapeutic targets. Herein, we matched autoantibody profiling of alveolar RMS (ARMS) patients with genes under regulatory control of PAX3-FOXO1 transcription factor and revealed fibroblast growth factor 8 (FGF8) as a novel ARMS tumor antigen of diagnostic, prognostic, and therapeutic potential. We demonstrated that high levels of FGF8 autoantibodies distinguished ARMS patients from healthy subjects and represented an independent prognostic factor of better event-free survival. FGF8 was overexpressed in ARMS tumors compared to other types of pediatric soft tissue sarcomas, acting as a positive regulator of cell signaling. Indeed, FGF8 was capable of stimulating ARMS cells migration and expression of pro-angiogenic and metastasis-related factors, throughout MAPK signaling activation. Of note, FGF8 was found to increase in recurrent tumors, independently of PAX3-FOXO1 expression dynamics. Risk of recurrence correlated positively with FGF8 expression levels at diagnosis and reduced FGF8 autoantibodies titer, almost as if to suggest a failure of the immune response to control tumor growth in recurring patients. This study provides evidence about the crucial role of FGF8 in ARMS and the protective function of natural autoantibodies, giving new insights into ARMS biology and laying the foundations for the development of new therapeutic strategies.
Asunto(s)
Rabdomiosarcoma Alveolar , Rabdomiosarcoma Embrionario , Autoanticuerpos/uso terapéutico , Factor 8 de Crecimiento de Fibroblastos , Humanos , Inmunidad , Recurrencia Local de Neoplasia , Factor de Transcripción PAX3 , Factores de Transcripción Paired Box/genética , Factores de Transcripción Paired Box/metabolismo , Factores de Transcripción Paired Box/uso terapéutico , Rabdomiosarcoma Alveolar/genética , Rabdomiosarcoma Alveolar/metabolismo , Rabdomiosarcoma Alveolar/patología , Rabdomiosarcoma Embrionario/genética , Rabdomiosarcoma Embrionario/metabolismoRESUMEN
Chimeric transcription factors drive lineage-specific oncogenesis but are notoriously difficult to target. Alveolar rhabdomyosarcoma (RMS) is an aggressive childhood soft tissue sarcoma transformed by the pathognomonic Paired Box 3-Forkhead Box O1 (PAX3-FOXO1) fusion protein, which governs a core regulatory circuitry transcription factor network. Here, we show that the histone lysine demethylase 4B (KDM4B) is a therapeutic vulnerability for PAX3-FOXO1+ RMS. Genetic and pharmacologic inhibition of KDM4B substantially delayed tumor growth. Suppression of KDM4 proteins inhibited the expression of core oncogenic transcription factors and caused epigenetic alterations of PAX3-FOXO1-governed superenhancers. Combining KDM4 inhibition with cytotoxic chemotherapy led to tumor regression in preclinical PAX3-FOXO1+ RMS subcutaneous xenograft models. In summary, we identified a targetable mechanism required for maintenance of the PAX3-FOXO1-related transcription factor network, which may translate to a therapeutic approach for fusion-positive RMS.
Asunto(s)
Rabdomiosarcoma Alveolar , Rabdomiosarcoma , Carcinogénesis/genética , Línea Celular Tumoral , Niño , Proteína Forkhead Box O1/metabolismo , Factores de Transcripción Forkhead/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Histona Demetilasas con Dominio de Jumonji/genética , Histona Demetilasas con Dominio de Jumonji/metabolismo , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Factor de Transcripción PAX3/genética , Factor de Transcripción PAX3/metabolismo , Factores de Transcripción Paired Box/genética , Factores de Transcripción Paired Box/metabolismo , Factores de Transcripción Paired Box/uso terapéutico , Rabdomiosarcoma/genética , Rabdomiosarcoma Alveolar/genética , Rabdomiosarcoma Alveolar/metabolismo , Rabdomiosarcoma Alveolar/patologíaRESUMEN
Muscular dystrophies (MDs) consist of a genetically heterogeneous group of disorders, recessive or dominant, characterized by progressive skeletal muscle weakening. To date, no effective treatment is available. Experimental strategies pursuing muscle regeneration through the transplantation of stem cell preparations have brought hope to patients affected by this disorder. Efficacy has been demonstrated in recessive MD models through contribution of wild-type nuclei to the muscle fiber heterokaryon; however, to date, there has been no study investigating the efficacy of a cell therapy in a dominant model of MD. We have recently demonstrated that Pax3-induced embryonic stem (ES) cell-derived myogenic progenitors are able to engraft and improve muscle function in mdx mice, a recessive mouse model for Duchenne MD. To assess whether this therapeutic effect can be extended to a dominant type of muscle disorder, here we transplanted these cells into FRG1 transgenic mice, a dominant model that has been associated with facioscapulohumeral muscular dystrophy. Our results show that Pax3-induced ES-derived myogenic progenitors are capable of significant engraftment after intramuscular or systemic transplantation into Frg1 mice. Analyses of contractile parameters revealed functional improvement in treated muscles of male mice, but not females, which are less severely affected. This study is the first to use Frg1 transgenic mice to assess muscle regeneration as well as to support the use of a cell-based therapy for autosomal dominant types of MD.
