Largaespada Laboratory

Neurofibromatosis Type 1 (NF1) syndrome is an autosomal dominant genetic disorder characterized by a predisposition to peripheral nerve sheath tumors called neurofibromas, optic pathway gliomas and other brain tumors, leukemia, pheochromocytoma, osteosarcoma and various other forms of cancer. We are using multiple model systems to explore genetic and other factors that cause NF1 associated tumors and to test new therapeutic interventions.  These include Sleeping Beauty (SB) transposon mutagenesis in mice, genetically engineered mouse models, engineered human Schwann cells, and a new porcine model of NF1.  New technologies for modeling brain tumors and new brain tumor genes are also being investigated using similar approaches. 

Immunofluorescence images of Schwann cells isolated from the sciatic nerve of a genetically engineered minipig

Green=GFAP (expressed by Schwann cells); Red=actin (stains the cytoskeleton); Blue=DAPI (stains the nucleus)

Immunofluorescent images of human medulloblastoma cells stained for ARHGAP36 expression

Green=cytoskeleton; Red=F-actin; Blue=nuclear DNA (blue)

Immunofluorescent image of mouse neuronal progenitor cells engineered to overexpress ARHGAP36

Green=ARHGAP36 expression; Red=cytoskeleton F-actin; Blue=nuclear DNA

Osteosarcomas are the most common form of primary bone tumor, with a peak incidence in adolescence.  While roughly 60% can be cured using surgery and adjuvant chemotherapy, when metastases occur the prognosis is dismal. We lack an understanding of what drives metastatic disease or what causes metastatic osteosarcoma to resist chemotherapy.  We have performed a Sleeping Beauty (SB) based forward genetic screen for osteosarcoma development and metastatic progression.  This approach is being complemented with whole genome CRISPR/Cas9 library screening in human cells.  Insight from these screens is being used to test new therapies using in vitro and in vivo model systems.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer related death worldwide. HCC usually occurs in the context of chronic liver damage such as that caused by chronic hepatitis infection, cirrhosis, or fatty liver disease. HCC are genetically complex and druggable drivers are still being sought. We have performed several Sleeping Beauty (SB) based forward genetic screens for HCC development and progression in male and female mice, in various genetic contexts, and in normal or damaged livers.  These data have suggested an interaction between specific gene mutations and pathways and the context in which HCC develops.  We hope to use this insight for new HCC prevention and treatment strategies. 

It has become increasingly clear that the immune system can be leveraged for cancer therapy.  This includes new methods for ex vivo genetic engineering of white blood cells for therapy, cancer vaccines and ways to enhance existing anti-tumor immunity.  We are combining genetics and immunology for cancer therapy in several ways.  This includes new methods for non-viral gene delivery and gene modification of human cells.  In addition, we’re investigating methods to make tumor cells more visible to the immune system using drugs to force cancer cells to express “cryptic neoantigens”. Prospectively identified cryptic neoantigens could be used as the basis for personalized cancer vaccines.