Effects of CCR4 antagonists in cutaneous T-cell lymphoma cells

CC chemokine receptor 4 (CCR4) is responsible for T-cell skin homing. It is overexpressed in type 2 helper T-cells (Th2) as well as cutaneous T-cell lymphoma (CTCL) cells. Mycosis fungoides (MF) and Sézary syndrome (SS) are two most common types of CTCL. Currently, Mogamulizumab, a humanized anti-CCR4 antibody, has been FDA-approved to treat MF and SS. However, the clinical response rates for SS patients was 30% and for MF patients was 22% and severe drug eruptions following treatment were reported. Thus, a more effective and less toxic strategy is needed for CCR4-targeted therapy. CCR4 antagonists have been studied in diseases where Th2 cells participate, such as asthma and atopic dermatitis, but little has been done for CTCL. Here, we tested two CCR4 antagonists, C021 (class I antagonist) and AZD2098 (class II antagonist), in MF derived cell line (MJ) and SS derived cell line (Hut78). The effects of two compounds on cell chemotaxis, proliferation, apoptosis, and Th2 cytokine secretion were assessed. As expected, CCR4 was highly expressed on MJ and Hut78 cells. MJ and Hut78 cells showed chemotactic responses to TARC/CCL17 and MDC/CCL22. Both C021 and AZD2098 inhibited chemotactic responses to TARC/CCL17 and MDC/CCL22 in MJ and Hut78 cells. Of note, C021 inhibited chemotaxis to CCL17 at a much lower concentration (IC50: 0.186 μM) than to CCL22 (1.3 μM) in MJ cells. AZD2098 inhibited chemotaxis to CCL17 at a much lower concentration (IC50: 0. 12 μM) than to CCL22 (0.866 μM) in Hut78 cells. Interestingly, only C021 downregulated CCR4 expression on cell surfaces. Only C021 inhibited cell proliferation, at a higher concentration (IC50: 3.21 μM in MJ cells; 5.98 μM in Hut78 cells), and induced cell apoptosis. AZD2098 had no such effect at any concentrations tested. In addition, the expressions of IL-5 and IL-13 proteins were decreased after treatment with C021 but not with AZD2098. Our results suggest that both CO21 and AZD2098 have inhibitory effects on chemotaxis of CTCL cells, but only C021 exerts other effects on CTCL cells. The in vivo study is on the way.