Modulation of AHR in peripheral blood mononuclear cells in pancreatic cancer research

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the fourth deadliest cancer type in the United States. Surgical intervention faces challenges at advanced stages, and immunotherapy encounters obstacles in PDAC application. Peripheral blood mononuclear cells (PBMCs) play a crucial role in anticancer response. Our previous analysis explored immunity imbalances related to low AHR expression in PDAC patients' PBMCs. The study aims to analyze possible anticancer response changes by AHR-activation or AHR-inhibition comparing with non-modulated PBMCs of same 15 PDAC patients. PBMCs of each patient were separated into three groups: negative control, AHR-activated with CARBIDOPA, and AHR-inhibited with BAY. After 24 hours cultivation, fresh PBMCs were analyzed by FACS, and cryopreserved PBMCs - by RT-PCR. Free proteins in media were analyzed by ELISA. Statistical analysis using GraphPad software and the Mann–Whitney test was performed. The results indicated a decreasing trend of AHR expression in AHR-activated PBMCs compared to other two groups. CYP1A1 expression was significantly upregulated in AHR-activated PBMCs and downregulated in AHR-inhibited cells. HMOX1 expression trend decreased in AHR-inhibited PBMCs, while PTGS2 - increased in AHR-activated cells. Trend of PD1 was overexpressed in both modulated groups, especially in AHR-inhibited PBMCs. Free PD1 level was higher in the media of AHR-activated cells and lower - in AHR-inhibited. T and B cells were more in both modulated groups but not significantly. Trend of M1 monocytes diminished in AHR-activated group and M0 cells multiplied. NK cells were less in AHR-inhibited PBMCs. IL10 secretion level slightly increased, while IL6 – decreased, in AHR-inhibited M1 type monocytes. In conclusion, this study delves into the impact of AHR modulation on PDAC patients' PBMCs, revealing insights into AHR's role and its self-difficult regulation. Modulation of AHR directly influenced CYP1A1 expression, reflecting changes in AHR functional activity. Interestingly, AHR expression showed decreasing trend only in AHR-activated PBMCs, what could be affected by the aryl hydrocarbon receptor repressor (AHRR) or other factors. While several other target genes and immune cell subtypes exhibited distinct trends, none achieved statistical significance. Further research with larger sample sizes and more target genes and proteins is essential for validating trends and understanding the complex interactions in PDAC patients' immunity.