Extracellular vesicles (EVs) are nanoscale membrane-derived vesicles that serve as intercellular messengers carrying lipids, proteins, and genetic material. Substantial evidence has shown that cancer-derived EVs, secreted by tumor cells into the blood and other bodily fluids, play a critical role in modulating the tumor microenvironment and affecting the pathogenesis of cancer. Here we demonstrate for the first time that squamous cell carcinoma (SCC) EVs were enriched with the C-terminal fragment of desmoglein 2 (Dsg2), a desmosomal cadherin often overexpressed in malignancies. Overexpression of Dsg2 increased EV release and mitogenic content including epidermal growth factor receptor and c-Src. Inhibiting ectodomain shedding of Dsg2 with the matrix metalloproteinase inhibitor GM6001 resulted in accumulation of full-length Dsg2 in EVs and reduced EV release. When cocultured with Dsg2/green fluorescence protein-expressing SCC cells, green fluorescence protein signal was detected by fluorescence-activated cell sorting analysis in the CD90 + fibroblasts. Furthermore, SCC EVs activated Erk1/2 and Akt signaling and enhanced fibroblast cell proliferation. In vivo, Dsg2 was highly up-regulated in the head and neck SCCs, and EVs isolated from sera of patients with SCC were enriched in Dsg2 C-terminal fragment and epidermal growth factor receptor. This study defines a mechanism by which Dsg2 expression in cancer cells can modulate the tumor microenvironment, a step critical for tumor progression.-Overmiller, A.

This study extends the previous findings of a systemic treatment effect of a unique combination product, IGV-001, in recurrent GBM. As an autologous tumor cell treatment, results were postulated to be an immune response. This follow-on phase Ib trial for newly diagnosed GBM was designed to further test this hypothesis with broad entry criteria. While the primary objective remained safety, unexpected clinical and radiographic responses prompted termination of randomization and accrual only to the highest exposure cohort after patient 23. The protocol amendment also elevated analysis of clinical endpoints from exploratory objectives to clinical endpoint assessments joining the established radiographic assessments. The results of this trial reflect compelling improvement in PFS in the ITT population and for PFS, OS and PFS MGMT methylated subgroups who would have met entry criteria for current phase 3 newly-diagnosed GBM trials. These clinical endpoint improvements were accompanied by striking radiographic improvements with sustained meaningful quality of life.