Small-molecule inhibitor BAY synergizes with gemcitabine through AHR inhibition in pancreatic cancer cells

Pancreatic cancer (PC) presents a significant challenge in treatment efficacy due to late-stage diagnosis and chemoresistance. The effects of the combination of a selective small-molecule AHR inhibitor and gemcitabine treatment effectiveness in PC cells has been a focus of research. This study utilized the PC cell lines BxPC-3 and Su.86.86 to investigate the impact of AHR activity modulation on gene and protein expression related to the gemcitabine response. Assays including viability measurement, combinational index calculation, qRT-PCR, Western blot analysis, immunocytofluorescence, and clonogenic assays, were employed. Additionally, patient tissue samples were analysed for AHR, ELAVL1, and DCK levels. The results show that AHR activity modulation influenced ELAVL1 localization, DCK expression, and gemcitabine response. Inhibition of AHR activity caused synergistic effects with gemcitabine, whereas activation had an antagonistic effect. Regarding colony formation, inhibition of AHR increased gemcitabine effectiveness by 30-41%, whereas activation decreased the response by 11-28%. Patient tissue analysis revealed correlations between AHR, ELAVL1, and DCK mRNA levels and showed increased levels of AHR protein (2.2-fold) and decreased DCK protein levels (36% decrease) in tumor tissue compared to next-to-cancer tissue. These findings demonstrate the potential of AHR modulation to improve gemcitabine treatment outcomes. This study highlights the significance of AHR modulation in influencing the gemcitabine response in PC cells. By inhibiting AHR activity, cells exhibited improved gemcitabine response, offering a promising avenue for enhancing treatment efficacy. These findings suggest that AHR could serve as a target for optimizing gemcitabine treatment and potentially reducing cancer aggressiveness.