Chromosome-specific induction of micronuclei and chromosomal aberrations by mitomycin C: Involvement of human chromosomes 9, 1 and 16

• Published in: Mutation research. Genetic toxicology and environmental mutagenesis 2024-05, Vol.896, p.503753, Article 503753
• Main Authors: Catalán, Julia, Järventaus, Hilkka, Falck, Ghita C.-M., Moreno, Carlos, Norppa, Hannu
• Format: Article
• Language: English
• Subjects: Adult; Cells, Cultured; Chromosomal aberrations; Chromosome 1; Chromosome 16; Chromosome 9; Chromosome Aberrations - chemically induced; Chromosome Aberrations - drug effects; Chromosomes, Human, Pair 1 - genetics; Chromosomes, Human, Pair 16 - genetics; Chromosomes, Human, Pair 9 - genetics; Cytochalasin B - pharmacology; Humans; In Situ Hybridization, Fluorescence; Lymphocytes - drug effects; Lymphocytes - metabolism; Male; Micronuclei, Chromosome-Defective - chemically induced; Micronuclei, Chromosome-Defective - drug effects; Micronucleus; Micronucleus Tests; Mitomycin - pharmacology; Mitomycin - toxicity; Mitomycin C
• ISSN: 1383-5718; 1879-3592; 1879-3592
• DOI: 10.1016/j.mrgentox.2024.503753

Cytogenetic studies have shown that human chromosomes 1, 9, and 16, with a large heterochromatic region of highly methylated classical satellite DNA, are prone to induction of chromatid breaks and interchanges by mitomycin C (MMC). A couple of studies have indicated that material from chromosome 9, and possibly also from chromosomes 1 and 16, are preferentially micronucleated by MMC. Here, we further examined the chromosome-specific induction of micronuclei (MN; with and without cytochalasin B) and chromosomal aberrations (CAs) by MMC. Cultures of isolated human lymphocytes from two male donors were treated (at 48 h of culture, for 24 h) with MMC (500 ng/ml), and the induced MN were examined by a pancentromeric DNA probe and paint probe for chromosome 9, and by paint probes for chromosomes 1 and 16. MMC increased the total frequency of MN by 6–8-fold but the frequency of chromosome 9 -positive (9+) MN by 29–30-fold and the frequency of chromosome 1 -positive (1+) MN and chromosome 16 -positive (16+) MN by 12–16-fold and 10–17-fold, respectively. After treatment with MMC, 34–47 % of all MN were 9+, 17–20 % 1+, and 3–4 % 16+. The majority (94–96 %) of the 9+ MN contained no centromere and thus harboured acentric fragments. When MMC-induced CAs aberrations were characterized by using the pancentromeric DNA probe and probes for the classical satellite region and long- and short- arm telomeres of chromosome 9, a high proportion of chromosomal breaks (31 %) and interchanges (41 %) concerned chromosome 9. In 83 % of cases, the breakpoint in chromosome 9 was just below the region (9cen-q12) labelled by the classical satellite probe. Our results indicate that MMC specifically induces MN harbouring fragments of chromosome 9, 1, and 16. CAs of chromosome 9 are highly overrepresented in metaphases of MMC-treated lymphocytes. The preferential breakpoint is below the region 9q12. •Mitomycin C-induced human micronuclei and chromosome aberrations were characterized.•Fluorescence in situ hybridization and chromosome paints in human lymphocytes were used.•Chromosomes 9, 1 and 16 are over-represented in induced micronuclei.•Chromosome 9 is highly involved in induced chromatid breaks and exchanges.•The preferential breakpoint in chromosome 9 is right below long arm band 9cen-q12.