p53-armed oncolytic adenovirus induces apoptosis in pancreatic cancer-associated stellate cells via macropinocytosis

Pancreatic ductal adenocarcinoma (PDAC)-associated pancreatic stellate cells (PSCs) promote PDAC tumor progression. Notably, PDAC tumors display enhanced macropinocytosis, resulting in enhanced uptake of extracellular particles, including nutrients and viruses. We previously demonstrated the therapeutic potential of telomerase-specific oncolytic adenoviruses OBP-301 and p53-armed OBP-702 against human PDAC cells. However, it remains unclear whether macropinocytosis promotes the virus sensitivity of PDAC-associated PSCs. Here, we show that PSCs activated by human PDAC cells (Panc-1 and BxPC-3) exhibit enhanced sensitivity to wild-type and oncolytic adenoviruses via enhanced macropinocytosis. The virus sensitivity of PSCs was analyzed for the infectivity, replication, and cytopathic activity of wild-type and oncolytic adenoviruses. PDAC-associated PSCs were more sensitive to wild-type and oncolytic adenoviruses than were control PSCs; this sensitivity was mediated by activation of macropinocytosis. In three-dimensional (3D) culture models, p53-armed OBP-702 decreased the viability of PDAC-associated PSCs more strongly than did non-armed OBP-301, reflecting induction of p53-mediated apoptosis. Co-inoculation of PSCs enhanced the growth of PDAC tumors, an effect that was attenuated by OBP-702-mediated p53 activation in the tumor stroma. Our results suggest that p53-armed oncolytic adenovirus OBP-702 eliminates PDAC-associated PSCs via enhancement of macropinocytosis-mediated virus entry and induction of p53-mediated apoptosis.