The Effects of Isoproterenol and Propranolol on Cytokine Profile Secretion by Cultured Tumor-infiltrating Lymphocytes Derived from Colorectal Cancer Patients

Objective: Anti-tumor immunity and cytokine profiles have important roles in the developmentof cancer. Norepinephrine (NE) release due to sympathetic activation leads toa Th2 deviation via the beta-2 adrenergic receptor (β-2AR) and could increase cancerprogression. This study intends to determine the effects of isoproterenol (ISO; betaagonist)and propranolol (PRO; beta-antagonist) on the production of IFN-γ, IL-4, andIL-17. Cytokine levels have been examined in tumor-infiltrating lymphocytes (TILs) andperipheral blood mononuclear cells (PBMCs) of patients with colorectal cancer (CRC).The β-2AR expression on lymphocyte subsets was also assessed.Materials and Methods: In this experimental study, TILs were isolated from freshCRC tissue and patient PBMCs were obtained just prior to surgery. The cells werecultured in medium for 72 hours. Concomitantly, cells were stimulated with 10 μg/ml phytohemagglutinin (PHA) alone or in the presence of either 1 μmol/L of PRO or1 μmol/L ISO. The concentration of cytokines in the supernatants was measured byELISA. Three-color flow cytometry was used to determine the expression of β-2AR onthe lymphocyte subsets. Statistical analyses were performed via paired or independentt-test.Results: Levels of IFN-γ, IL-4 and IL-17 were elevated after PHA-stimulation of PBMCsand TILs. However, the elevation of IFN-γ and IL-17 production by TILs in response to PHAwas significantly lower than PBMCs. In the presence of ISO, the IFN-γ/IL-4 ratio reducedin all groups, but this reduction was very low in TILs. Interestingly, the effects of PRO oncytokine production were, at least partially, comparable to those of ISO. Depressed levelsof β-2AR expression were demonstrated on CD4+IFN-γ+ and CD4+IL-17+ lymphocytesin patients’ PBMCs and TILs.Conclusion: This study has demonstrated the effects of ISO and PRO on cytokine productionby TILs and determined β-2AR expression on these cells. ISO failed to induce ashift toward the expected Th2 cytokine profile in CRC patients’ TILs, which might be due tothe downregulation of β-2AR expression on TILs. Additionally, in this study, PRO induceda shift to a Th2 profile in PBMCs.