Abstract 47P
Background
The overexpression of the immunoinhibitory receptor programmed death-1 (PD1) on T-cells is involved in immune evasion in cancer and reduced clearance of pathogens during chronic infections. Antifungal imidazole derivatives are commonly used for the treatment of topical and systemic infection. The pharmacokinetic dynamics and toxicity of these drugs are now established, suggesting their potential use in other human pathologies treatment including several cancers. Of these Sulconazole (SCZ), is known as ligands of the heme iron atom of the cytochrome P450 (CYP). SCZ was recently reported to inhibit the malignant phenotype of some cancer cells.
Methods
In the current study, activation of human T cell lines Jurkat and J.RT3-T3.5 (JRT3) was induced by phorbol myristate acetate (PMA) and Ionomycin (Io). Activated T cells were then cultured with various concentration of SCZ. TCR-deficient human T cells JRT3, expressing a specific TCR (LES) able to recognize the EPCR protein (JRT3-LES) were cocultured with the colon cancer cells HT29 that stably express EPCR (HT29-EPCR). Activation of T cells and relative expression of PD-1 was evaluated by RT-PCR, immunofluorescence (IF) and flow cytometry analysis. NF-κB pathway was analyzed by western-blotting.
Results
We found that SCZ considerably repressed PD-1 RNA on PMA-iono activated T cells (p<0.05), without affecting their activated status. Flow cytometry and IF analysis confirmed that the expression of PD-1 in activated T cells was decreased by SCZ in a dose-dependent manner (p<0.05). On another hand, coculture of JRT3-LES and HT29-EPCR in presence of sulconazole revealed activated CD69 expressing state of T cells was not affected by SCZ. Activation of T cells with PMA/Io stimulated NF-κB phosphorylation. SCZ significantly repressed NF-κB signaling involved in the induction of PD-1 (p<0.05). Likewise, NF-κB expression inhibition using NF-κB inhibitor repressed PD-1 expression.
Conclusions
SCZ decrease PD-1 expression on activated T cells, without affecting their activated status, through NF-κB-dependent manner. These results suggest the SCZ therapeutic potential used alone or as adjunct strategy to prevent T-cell exhaustion to improve immunotherapy in cancers.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
S. Pernot: Financial Interests, Personal, Invited Speaker: Amgen, BMS, Merck, Servier, Pierre Fabre, Sanofi, Bayer. All other authors have declared no conflicts of interest.