Comparison of the inhibition of recombinant and native heme oxygenase-1 (HO-1) activity by the imidazoledioxolane compound QC-15

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Nick Stone


Recombinant full-length and truncated forms of human heme oxygenase-1 (hHO-1) were compared with their native, microsomal HO-1 counterpart from rat spleen tissue, with respect to their inhibition by the imidazole-dioxolane HO inhibitor QC-15. Rat native HO-1 was maximally inhibited to the greatest extent (7.53 ± 1.51% of control activity), as compared to recombinant, full-length hHO-1 (55.55 ± 6.08%), and also truncated hHO-1 (72.17 ± 5.94%). The greater susceptibility of native HO-1 to QC-15 inhibition may be attributed to the presence of its C-terminal transmembrane domain (CTD) and its anchoring into the endoplasmic reticulum (ER). If so, membrane-anchored, recombinant, full-length hHO-1 may replace the current HO-1 microsomal model derived from rat spleen, in future in vitro inhibition studies. A better understanding of HO-1 inhibitors like QC-15 may lead to chemotherapeutics that prevent tumour cells from taking advantage of the cytoprotective nature of the HO system.

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Author Biography

Nick Stone, Queen’s University, Kingston, ON, Canada

Supervised by: Brian McLaughlin and Kanji Nakatsu, Department of Biomedical and Molecular Sciences Botterell Hall, Queen’s University, Kingston, ON, Canada