TIM-3 blockade in diffuse intrinsic pontine glioma models promotes tumor regression and antitumor immune memory

Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain stem tumor and the leading cause of pediatric cancer-related death. To date, these tumors remain incurable, underscoring the need for efficacious therapies. In this study, we demonstrate that the immune checkpoint TIM-3 (HAVCR2) is highly expressed in both tumor cells and microenvironmental cells, mainly microglia and macrophages, in DIPG. We show that inhibition of TIM-3 in syngeneic models of DIPG prolongs survival and produces long-term survivors free of disease that harbor immune memory. This antitumor effect is driven by the direct effect of TIM-3 inhibition in tumor cells, the coordinated action of several immune cell populations, and the secretion of chemokines/cytokines that create a proinflammatory tumor microenvironment favoring a potent antitumor immune response. This work uncovers TIM-3 as a bona fide target in DIPG and supports its clinical translation

Comparative cellular biology of vetebrate primordial oocytes

En este proyecto, hemos desarrollado métodos que permiten la caracterización comparativa basada en imágenes en vivo de ovocitos primordiales de humano, ratón y Xenopus. Mostramos que los ovocitos primordiales en las tres especies de vertebrados contienen lisosomas, aparato de Golgi y mitocondrias activos. Mientras que los ovocitos humanos y de Xenopus tienen el cuerpo de Balbiani caracterizado por una densa acumulación de mitocondrias en su citoplasma, en los ovocitos de ratón no encontramos un cuerpo de Balbiani. En cambio, demostramos que lo que se usó previamente como marcador para el cuerpo de Balbiani en ovocitos primordiales de ratón es, de hecho, un aparato de Golgi en forma de anillo que no está asociado funcionalmente con la latencia de los ovocitos. Nuestro trabajo proporciona los primeros conocimientos sobre la organización del citoplasma en los ovocitos primordiales de mamíferos y aclara las ventajas y limitaciones relativas de elegir diferentes organismos modelo para estudiar la latencia de los ovocitos.In this project, we have developed enabling methods for live-imaging based comparative characterization of Xenopus, mouse and human primordial oocytes. We show that primordial oocytes in all three vertebrate species contain active lysosomes, Golgi apparatus and mitochondria. While human and Xenopus oocytes have a Balbiani body characterized by a dense accumulation of mitochondria in their cytoplasm, we did not find a Balbiani body in mouse oocytes. Instead, we demonstrate what was previously used as a marker for the Balbiani body in mouse primordial oocytes is in fact a ring-shaped Golgi apparatus that is not functionally associated with oocyte dormancy. Our work provides the first insights into the organization of the cytoplasm in mammalian primordial oocytes, and clarifies relative advantages and limitations of choosing different model organisms for studying oocyte dormancy

Comparative analysis of vertebrates reveals that mouse primordial oocytes do not contain a Balbiani body

Oocytes spend the majority of their lifetime in a primordial state. The cellular and molecular biology of primordial oocytes is largely unexplored; yet, it is necessary to study them to understand the mechanisms through which oocytes maintain cellular fitness for decades, and why they eventually fail with age. Here, we develop enabling methods for live-imaging-based comparative characterization of Xenopus, mouse and human primordial oocytes. We show that primordial oocytes in all three vertebrate species contain active mitochondria, Golgi and lysosomes. We further demonstrate that human and Xenopus oocytes have a Balbiani body characterized by a dense accumulation of mitochondria in their cytoplasm. However, despite previous reports, we did not find a Balbiani body in mouse oocytes. Instead, we demonstrate that what was previously used as a marker for the Balbiani body in mouse primordial oocytes is in fact a ring-shaped Golgi that is not functionally associated with oocyte dormancy. This study provides the first insights into the organization of the cytoplasm in mammalian primordial oocytes, and clarifies the relative advantages and limitations of choosing different model organisms for studying oocyte dormancy.This study was supported by a European Research Council Starting Grant (ERC-StG-2017-759107) and the Ministerio de Ciencia e Innovación (MINECO - BFU2017-89373-P and PID2020-115127GB-I00 to E.B.). G.Z. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 754422. M.S. is supported by a Juan de la Cierva-Formación fellowship from the Ministerio de Ciencia e Innovación (FJC2019-041607-I; AEI; 10.13039/501100011033)