Synthesis and in vitro characterization of the genotoxic, mutagenic and cell-transforming potential of nitrosylated heme

authored by

Tina Kostka, Jörg Fohrer, Claudia Guigas, Karlis Briviba, Nina Seiwert, Jörg Fahrer, Pablo Steinberg, Michael T. Empl

Abstract

Data from epidemiological studies suggest that consumption of red and processed meat is a factor contributing to colorectal carcinogenesis. Red meat contains high amounts of heme, which in turn can be converted to its nitrosylated form, NO-heme, when adding nitrite-containing curing salt to meat. NO-heme might contribute to colorectal cancer formation by causing gene mutations and could thereby be responsible for the association of (processed) red meat consumption with intestinal cancer. Up to now, neither in vitro nor in vivo studies characterizing the mutagenic and cell transforming potential of NO-heme have been published due to the fact that the pure compound is not readily available. Therefore, in the present study, an already existing synthesis protocol was modified to yield, for the first time, purified NO-heme. Thereafter, newly synthesized NO-heme was chemically characterized and used in various in vitro approaches at dietary concentrations to determine whether it can lead to DNA damage and malignant cell transformation. While NO-heme led to a significant dose-dependent increase in the number of DNA strand breaks in the comet assay and was mutagenic in the HPRT assay, this compound tested negative in the Ames test and failed to induce malignant cell transformation in the BALB/c 3T3 cell transformation assay. Interestingly, the non-nitrosylated heme control showed similar effects, but was additionally able to induce malignant transformation in BALB/c 3T3 murine fibroblasts. Taken together, these results suggest that it is the heme molecule rather than the NO moiety which is involved in driving red meat-associated carcinogenesis.

Organisation(s)

Institute of Organic Chemistry

External Organisation(s)

University of Veterinary Medicine of Hannover, Foundation
Max Rubner-Institut (MRI), Federal Research Institute of Nutrition and Food
University of Kaiserslautern

Type

Article

Journal

Archives of toxicology

Volume

94

Pages

3911-3927

No. of pages

17

ISSN

0340-5761

Publication date

11.2020

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Toxicology, Health, Toxicology and Mutagenesis

Sustainable Development Goals

SDG 3 - Good Health and Well-being

Electronic version(s)

https://doi.org/10.1007/s00204-020-02846-8 (Access: Open)