Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease marked by poor response to virtually all available treatments. Clinical trials of chemo, targeted therapies, and radiation, have resulted in minimal advances, and survival after diagnosis is generally less than a year. In the pursuit of new avenues for therapeutic development for this lethal disease, a number of studies have implicated the role of tumor-promoting microRNAs with altered expression PDAC tissues. Here, using in vitro 3D organoids we explore the strategy of combining photodynamic therapy (PDT) with a novel microRNA therapeutic platform to target miR21, an established onco-miR that targets multiple tumor suppressors. This approach is motivated by recent clinical studies establishing the technical feasibility of light delivery to the pancreas, combined by evidence that PDT may disrupt or loosen stroma and potentially increase delivery of anti-miR agents. To evaluate this hypothesis, we use in vitro co-culture models of PDAC cells and stromal fibroblasts that recapitulate the dense fibrotic stroma of PDAC tumors to evaluate response to treatment in verteporfin PDT and anti-miR combination and monotherapy treatment arms. Using stably-transfected miR-21 sponge expressing we also perform mechanistic studies to investigate the role of miR 21 in response to PDT and chemotherapy in 3D cultures with and without stromal partners.
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