Transcription Factor-Forced Astrocytic Differentiation Impairs Human Glioblastoma Growth In Vitro and In Vivo.

Direct cellular reprogramming has recently gained attention of cancer researchers for the possibility to convert undifferentiated cancer cells into more differentiated, postmitotic cell types. While a few studies have attempted reprogramming of glioblastoma (GBM) cells toward a neuronal fate, this approach has not yet been used to induce differentiation into other lineages and in vivo data on reduction in tumorigenicity are limited. Here, we employ cellular reprogramming to induce astrocytic differentiation as a therapeutic approach in GBM. To this end, we overexpressed key transcriptional regulators of astroglial development in human GBM and GBM stem cell lines. Treated cells undergo a remarkable shift in structure, acquiring an astrocyte-like morphology with star-shaped bodies and radial branched processes. Differentiated cells express typical glial markers and show a marked decrease in their proliferative state. In addition, forced differentiation induces astrocytic functions such as induced calcium transients and ability to respond to inflammatory stimuli. Most importantly, forced differentiation substantially reduces tumorigenicity of GBM cells in an in vivo xenotransplantation model. The current study capitalizes on cellular plasticity with a novel application in cancer. We take advantage of the similarity between neural developmental processes and cancer hierarchy to mitigate, if not completely abolish, the malignant nature of tumor cells and pave the way for new intervention strategies.

Durable response after immunotherapy discontinuation for delayed and severe immune-related adverse events: a case report.

Recent studies have shown that immune-related adverse events (irAEs), occurring even after the discontinuation of immune checkpoint inhibitors (ICIs), may be associated with favorable disease outcomes, particularly in patients with melanoma and lung cancer. However, a few clinical cases have been described on the correlation between irAEs and ICIs efficacy in renal cell carcinoma (RCC) patients. This study reports the clinical case of a metastatic RCC patient who has experienced severe immune-related renal toxicity after 19 months of nivolumab use. Despite immunotherapy discontinuation, the patient has maintained clinical benefit and disease progression-free for 3 years. We examined the correlation between the occurrence and the severity of irAEs, treatment discontinuation and clinical benefits. The evidence on ICI retreatment following ICI discontinuation due to irAEs was also reviewed.

Lay abstract Immunotherapy has profoundly changed the treatment scenario of cancer patients. However, similar to any oncological therapy, it may cause immune-related adverse events. Cancer patients experiencing immune-related adverse events have a higher probability of better survival outcomes. This correlation has been largely described in patients with melanoma and lung cancer, but only a few data have been reported for genitourinary tumor patients. Here, we report the clinical case of a metastatic renal cell carcinoma patient who has experienced a late-onset and severe immune-related renal toxicity after 19 months of immunotherapy, which led to treatment discontinuation. Despite this, the patient has maintained a clinical benefit and disease progression-free for more than 3.5 years. We reviewed the literature on the correlation between immunotherapy benefit and immune-related adverse events, considering the time of onset, the severity of the adverse events and the concepts of treatment discontinuation and retreatment.

Modelling genetic mosaicism of neurodevelopmental disorders in vivo by a Cre-amplifying fluorescent reporter.

Genetic mosaicism, a condition in which an organ includes cells with different genotypes, is frequently present in monogenic diseases of the central nervous system caused by the random inactivation of the X-chromosome, in the case of X-linked pathologies, or by somatic mutations affecting a subset of neurons. The comprehension of the mechanisms of these diseases and of the cell-autonomous effects of specific mutations requires the generation of sparse mosaic models, in which the genotype of each neuron is univocally identified by the expression of a fluorescent protein in vivo. Here, we show a dual-color reporter system that, when expressed in a floxed mouse line for a target gene, leads to the creation of mosaics with tunable degree. We demonstrate the generation of a knockout mosaic of the autism/epilepsy related gene PTEN in which the genotype of each neuron is reliably identified, and the neuronal phenotype is accurately characterized by two-photon microscopy.