Pancreatic ductal adenocarcinoma (PDAC) is the most lethal of all solid malignancies, with most patients succumbing to the disease within 6 months of diagnosis and only ~12% of patients surviving beyond 5 years. PDAC onset, progression and treatment response is associated with aberrant inflammation. For example, patients with chronic pancreatitis [1] or type II diabetes [2] have an increased risk of PDAC. Understanding the triggers and impact of inflammation could improve early detection, screening of those at risk of PDAC, and treatment options.
Many viruses can trigger inflammation. Emerging evidence has shown that SARS-CoV-2, a virus that caused the COVID-19 pandemic, can affect multiple organs. In particular, there is a strong correlation between severity of SARS-CoV-2 infection and pancreatic injury and inflammation [3, 4]. However, the mechanism underlying how SARS-CoV-2 infection leads to pancreatic impairment and how this may influence the development of PDAC has not been explored yet.
We hypothesised that SARS-CoV-2 infection would lead to inflammation of the pancreas, resulting in a pro-tumorigenic microenvironment. To this end, we infected a cohort of PDAC predisposed Pdx-1-Cre; LSL-KrasG12D/+ (KC) mice with a mouse adapted SARS-CoV-2 virus strain [5] that recapitulates key features of human COVID-19 disease. Immune cells within the pancreas microenvironment were quantified by flow cytometry and histopathology of pancreas tissue characterised.
Compared to uninfected littermate KC controls, we observed increased immune infiltration within the pancreas of SARS-CoV-2 infected mice, with the most striking changes including myeloid cell populations. We also observed an increase in the presence of inflammatory fibroblasts, which are a major source of pro-tumorigenic cytokines and linked to poor survival in PDAC.
We have shown that the pancreas becomes inflamed following SARS-CoV-2 infection in mice, consistent with emerging epidemiological studies. We have further shown, using the KC model, that SARS-CoV-2 infection leads to changes in the microenvironment and we are now investigating whether these changes will alter the progression of pancreatic cancer.