STUDY OF THE EFFECTS OF LEUKOTRIENE A4 HYDROLASE INHIBITION ON THE HEPATOCELLULAR CARCINOMA CELL LINE HUH7

FRATTINI M; QUIROGA AD

Congreso; Sociedad Argentina de FIsiología; 2023

Introduction: Leukotriene B4 (LTB4) is a lipid mediator synthesized from the hydrolysis of the precursor LTA4 by the action of theenzyme leukotriene A4 hydrolase (LTA4H). Our group demonstrated that the LTB4 signaling pathway plays an important role incontrolled proliferation during liver regeneration after partial hepatectomy; thus, it is also likely for it to play a role inuncontrolled proliferation occurring in liver cancer. Indeed, an overproduction of LTB4 has been shown in other types of humancancers, leading to proliferation of cancer cells. Objectives: To analyze the effects on specific behavior associated withmalignancy of tumor liver cancer cells, upon inhibition of the enzyme LTA4H. Methods: Human hepatocellular carcinoma (HCC)Huh7 cells were treated with the LTA4H inhibitors bestatin (BST) and SC-57461A (SC) or left untreated (control, C). Studies in 2Dcultures (C, BST and SC groups): cell viability, migration, clonogenicity, invasion, flow cytometry and the expression of keyproteins for proliferation and apoptosis. Studies in 3D cultures (C and SC groups): viability, proliferation and migration.and lungs were excised and analyzed. Results: Primary tumors from hypothyroid mice exhibited a higher mRNA expression ofVimentin and a lower expression of E-cadherin than tumors from eu- and hyperthyroid animals (p<0.05). In these tumors, nodifferences in the activity of MMP-2 and MMP-9 were detected by gelatinolytic zymography. Additionally, tumors fromhypothyroid mice showed increased mRNA expression levels of CCL-5, CCL-2 and CXCL-16 chemokines, when compared withtumors from eu- and hyperthyroid mice (p<0.05). Increased secretion levels of CCL-2 were also detected in tumors and lungsfrom hypothyroid mice (p<0.05). The analysis of the distribution of immune subsets by flow cytometry showed a higherproportion of cytotoxic T cells (p<0.05) and B cells (p<0.05) in lungs from hyperthyroid mice, but an increased proportion ofmyeloid-derived suppressor cells CD11+Gr1+ (p<0.05) in lungs from hypothyroid mice. Conclusion: Our results suggest thatthyroid status modulates the development of breast cancer metastasis through the regulation of the EMT process, the secretionof chemokines by the primary tumor and the distribution of subpopulations of immune cells that infiltrate metastatic sites.