Evidence for an Aneugenic Mechanism of Action for Micronucleus Induction by Black Cohosh Extract

Abstract

Black cohosh extract (BCE) is a popular botanical dietary supplement marketed to relieve symptoms of various gynecological ailments. Studies conducted by the National Toxicology Program (NTP) showed that BCE induces micronucleated erythrocytes in female rats and mice. Subsequently, the NTP showed that a variety of BCEs, including the sample that induced micronuclei (MN) in vivo (“NTP BCE”) had a similar effect in human TK6 cells. Further testing with the MultiFlow® DNA Damage Assay revealed that TK6 cells exposed to NTP BCE, as well as a BCE reference material (BC XRM), exhibited a signature consistent with aneugenic activity in TK6 cells. Results from experiments reported herein confirmed these in vitro observations with NTP BCE and BC XRM. We extended these studies to include a novel test system, the MultiFlow Aneugen Molecular Mechanism Assay. For these experiments, TK6 cells were exposed to NTP BCE and BC XRM over a range of concentrations in the presence of fluorescent Taxol (488 Taxol). After 4 h, nuclei from lysed cells were stained with a nucleic acid dye and labeled with fluorescent antibodies against phospho‐histone H3 (p‐H3) and Ki‐67. Whereas BCEs did not affect p‐H3:Ki‐67 ratios (a signature of aneugenic mitotic kinase inhibitors), 488 Taxol‐associated fluorescence (a tubulin binder‐sensitive endpoint) was affected. More specifically, 488 Taxol‐associated fluorescence was reduced over the same concentration range that was previously observed to induce MN. These results provide direct evidence that BCEs destabilize microtubules in vitro, and this is the molecular mechanism responsible for the aneugenicity findings. Environ. Mol. Mutagen. 2019. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

In Vitro Analysis of Genotoxic Effects of Dental Panoramic Radiography: Evidence of Potential Genotoxicity Using the Comet Test

“…However, DNA damage can affect only one strand (single strand breaks, SSBs), without leading to the formation of micronuclei. Additionally, the presence of micronuclei may be related to an aneugenic effect, that is, a disturbance in the cell division process, which may be related to changes in the division apparatus, leading to the isolation of entire chromosomes (BERNACKI et al, 2019).…”

A cross‐sectional clinical study in women to investigate possible genotoxicity and hematological abnormalities related to the use of black cohosh botanical dietary supplements

“…MN may be formed via two basic mechanisms: whole chromosome loss (aneugenicity), or failure of an acentric, broken chromosome (clastogenicity) to migrate to a spindle pole during mitosis. The DNTP BC extract was shown to induce MN through destabilization of microtubules, resulting in whole chromosome loss during mitosis (Bernacki et al, 2019). Additional studies have provided some evidence that the DNTP BC extract may have transient DNA‐damaging effects as well (Seo et al, 2021).…”

Citrinin against breast cancer: A cytogenotoxicological study

“…There is evidence that CIT increases MN formation and induces apoptosis (Sabharwal et al, 2015). Formation of MN could be attributed to chromosomal breaks, indicating clastogeny, and by loss of chromosomes by the effects of aneugenic agents (Bernacki et al, 2019). Research findings indicated that CIT induces BC in the hepatocytes that may be an indication of cytokinesis failures at the end of cell division, and cells with condensed chromatin are signs of apoptosis (karyorrhexis and karyolysis) as well as picnoses (Sabharwal et al, 2015).…”