Targeting AHR decreases PDAC cell migration and invasiveness in 2D and 3D systems, in vitro

Abstract

Aryl hydrocarbon receptor (AHR) is a transcription factor that’s commonly upregulated in pancreatic ductal adenocarcinoma (PDAC). There are evidence that upregulated AHR increases PDAC aggressiveness, invasiveness, migration and decreases survival rates. This can be linked to epithelial-mesenchymal transition, when cells acquire a migratory mesenchymal phenotype. AHR expression levels have been shown to influence epithelial or mesenchymal phenotype in some cancer types, however little is known how targeting AHR would affect cell migration and invasiveness in pancreatic cancer. The aim of this study was to investigate how targeting AHR would affect cell migration and invasiveness in pancreatic cancer cells. Two PDAC cell were used for the study (BxPC-3 and Su.86.86). AHR was silenced by lipofectamine mediated siRNA transfection, inhibited by AHR inhibitor (BAY compound) or knocked-out by using CRISPR-CAS system. After silencing, inhibiting or knocking-out AHR, scratch assay was performed to asses the effect on cell migration in 2D system. AHR protein inhibition influence on cell invasiveness and migration was also assessed in 3D system by growing them in low-adherence plates until they formed spheroids. The spheroids were then moved into adherence allowing plates to asses migration. Alternatively the spheroids were put into an extracellular matrix to asses invasion. The results showed that targeting AHR decreases PDAC cells migration and invasiveness. 2D Scratch assay showed that the migration was decreased by silencing AHR (BxPC-3 by 73 %; Su.86.86 by 54 %), inhibiting (BxPC-3 by 36 %; Su.86.86 – no change) and knocking-out (BxPC-3 by 51 %; Su.86.86 – KO not tested). 3D spheroid assays revealed similar trends of reducing cell migration (by 33-41 % depending on cell line) and invasiveness (by 20-43 % depending on cell line) after inhibiting AHR with BAY compound. Targeting AHR could prove to be a viable strategy in slowing PDAC progression by reduce cell invasiveness and migratory capabilities, however differences between cell lines suggest that such strategy should be pursued as a personalized treatment with other molecular mechanisms in mind.