Abstract 5234: Expression of cytochrome P450 in head and neck cancer cell lines

Abstract

Abstract Background: The high expression of cytochrome P450 (CYP) enzymes including isoforms CYP1A1, 1B1 and 2W1 in some tumor types compared to normal tissue make these potential targets for targeted drug discovery. Our efforts in this space have resulted in the discovery of duocarmycin bioprecursors that are bioactivated by CYP1A1 and CYP2W1 expressed in malignant tissues1-2. Epidemiological studies have shown that head and neck cancer (HNC) is a complex multistage process that in part involves exposure to a combination of carcinogens and the capacity of certain drug-metabolising enzymes including CYPs to detoxify or activate such carcinogens. Here, we report on the expression of CYP1A1, CYP1B1 and CYP2W1 in HNC cell lines and human primary tissues. Materials and methods: A panel of HNC cell lines (FaDu, Detroit-562, A253, OSC19) was characterized for CYP1A1, CYP1B1 and CYP2W1 gene expression using real time PCR. Furthermore, immunofluorescence (IF) was used to detect protein expression in HNC cell lines and immunohistochemistry (IHC) in xenografts, paraffin-embedded and snap-frozen human HNC tissue. Anti-proliferative activity was measured using the MTT assay and DNA damage was measured using the comet assay. Results: In the HNC cell lines significant expression (5-10 fold) was shown at the gene level for CYP1A1 and CYP1B1 whereas CYP2W1 was hardly detected. However, CYP2W1 was expressed in FaDu and Detroit xenografts and in a small cohort of 10 human HNC samples as measured by IF and IHC, respectively. In agreement with CYP1 expression, the cytotoxicity results of ICT2700 and ICT2706 revealed FaDu and Detroit-562 as the most sensitive HNC cell lines suggesting bioactivation of these two lead duocarmycin bioprecursors. Conclusion: Accordingly, from these data we can conclude that CYP1A1, CYP1B1 and CYP2W1 are expressed in selected HNC cell lines and tumor tissue. In addition, early evidence suggests that CYP2W1 expression is stimulated by the presence of an in vivo microenvironment. However a larger cohort (≥ 60) of clinical HNC samples will be used to confirm this observation and will be reported at the annual AACR meeting. [1] Sheldrake et al.Reengineering of the duocarmycin structural architecture enables bioprecursors development targeting CYP1A1 and CYP2W1 for biological activity. J Med Chem. 2013, 56, 62737. [2] Travica et al. Colon cancer-specific cytochrome P450 2W1 converts duocarmycin analogues into potent tumor cytotoxins. Clin Cancer Res. 2013, 19, 295261. Citation Format: Daniela F. Presa, Goreti Ribeiro Morais, Mark Sutherland, Jim McCaul, Jacques Robert, Laurence Patterson, Klaus Pors. Expression of cytochrome P450 in head and neck cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5234. doi:10.1158/1538-7445.AM2017-5234