Abstract LB259: Circulating immune cells of patients with cervical dysplasia and cancer do not show elevated baseline expression of COX2

Abstract

Abstract Background and objective: COX2, an enzyme that metabolizes arachidonic acid to prostaglandin E2 (PGE2), contributes to the development of cervical dysplasia and cancer by inhibiting the immune response in the tumor micro-environment, as well as promoting cell proliferation, angiogenesis and invasiveness. Little is known about the changes induced by the tumor and its micro-environment on circulating immune cells. We evaluated the relative baseline expression of COX2 by circulating immune cell types and whether it is different in patients with cervical dysplasia and cervical cancer compared to normal controls. Methods: Forty three patients were included: controls (n = 9), low grade dysplasia (CIN I, n = 13), high grade dysplasia (CIN II-III, n = 14), and invasive cervical cancer (n = 7) based on histopathology. Granulocytes, monocytes, and B and T lymphocytes were isolated by Ficoll-Paque density centrifugation (GE Healthcare, (Uppsala, Sweden)) followed by negative selection with MACS Miltenyi Biotec (Auburn, CA) anti-biotinylated microbeads, total RNA isolated (QIAGEN RNeasy (Germantown, MD)) and COX2 mRNA expression evaluated with reverse transcription quantitative PCR (RT-qPCR) normalized to GAPDH levels. Serum and plasma PGE2 levels were quantified by enzyme linked immunoassay (ELISA) (R&D Systems (Mineappolis, MN)). Results: There were marked differences in COX2 expression between the various cell types (p <0.0001, Kruskal-Wallis) with granulocytes producing the highest levels, comparable to GAPDH (1.56 ± 1.46), monocytes an intermediate amount (0.083 ± 0.086), and B and T cells very small amounts (0.033 ± 0.108 and 0.017 ± 0.079 respectively). There was no significant difference in COX2 expression by disease state. B and T cells trended toward significance (p 0.055 and p 0.08 respectively) with the relative expression of COX2 increasing with disease severity. The importance of this is not clear given the very low levels of expression. Plasma PGE2 levels differed significantly by disease state (p 0.0014) with mean levels of controls: 1083 ± 722 pg/mL, low grade: 1208 ± 576 pg/mL, and high grade: 1415 ± 2127 pg/mL. Surprisingly, levels in patients with invasive cancer were low, 464 ± 182 pg/mL. Discussion: This is the first exhaustive study of baseline COX2 expression in circulating immune cell types in any HPV-associated disease to the authors' knowledge. We have previously reported that circulating monocytes from patients with HPV-induced premalignant upper airway lesions show altered immune functions in response to stimuli compared to monocytes from normal controls. Future studies are necessary to determine whether circulating immune cells from patients with cervical dysplasia and cancer show pro-tumorigenic or immune down-regulating activity in response to stimuli. Citation Format: Bethany Bustamante, James A. DeVoti, Chris J. Papayannakos, Mohd Israr, Fung Lam, Bettie Steinberg, Vincent Bonagura, Gary L. Goldberg. Circulating immune cells of patients with cervical dysplasia and cancer do not show elevated baseline expression of COX2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB259.