Comparison of gene expression changes induced in mouse and human cells treated with direct‐acting mutagens

Abstract

Exposure to DNA-damaging agents can elicit a variety of stress-related responses that may alter the gene expression of numerous biological pathways. We used Affymetrix microarrays to detect gene expression changes in mouse lymphoma (L5178Y) and human lymphoblastoid (TK6) cells in response to methyl methanesulfonate (MMS; a prototypical alkylating agent) and bleomycin (a prototypical oxidative mutagen). Cells were treated for 4 hr, and RNA was isolated either at the end of the treatment or after a 20-hr recovery period. Two concentrations of each agent were used based on cytotoxicity levels and Tk mutant frequencies. Our microarray data analysis indicated that MMS and bleomycin gene expression responses were considerably different in mouse cells versus human cells. The results also suggested that more comprehensive cellular responses to MMS and bleomycin occurred in TK6 cells than in L5178Y cells. In contrast to L5178Y cells, the response of TK6 cells to MMS and bleomycin was characterized by the induction of p53-dependent genes that are involved in DNA repair, cell cycle regulation, and apoptosis. It appears that the induction of DNA damage by MMS in human TK6 cells mediated cytotoxicity and led to decreased cell survival. This may explain the greater sensitivity of TK6 cells to cytotoxic effects of MMS compared to L5178Y cells. Bleomycin exerted comparable cytotoxic effects in the two cell lines. Overall, these studies were unable to identify distinctive gene expression changes that differentiated bleomycin from MMS in either TK6 cells or mouse lymphoma cells.

MondoA is highly overexpressed in acute lymphoblastic leukemia cells and modulates their metabolism, differentiation and survival

“…3B and Supplementary Table 2). For instance, the gene-set STEMCELL COMMON DN (now renamed in RAMALHO STEMNESS DN) contains genes, which are usually depleted in embryonic, neural and hematopoietic stem cells [29], whereas the gene-set BLEO HUMAN LYMPH HIGH 4HRS UP comprises genes involved in DNA repair, cell cycle regulation, and apoptosis, which are differentially regulated in human lymphocytes 4 h following treatment with a high dose of bleomycin [30].…”

Genomic Approaches for Investigating Mechanisms of Genotoxicity

“…Therefore, the pathway analysis is crucial for evaluating genotoxic mechanism. This has also become apparent in studies performed by participating laboratories in HESI Genomic consortium (Akerman et al 2004;Dickinson et al 2004;Hu et al 2004;Islaih et al 2004;Seidel et al 2003Seidel et al , 2004 and others (reviewed in Aubrecht and Caba 2005). Although the HESI Genomic consortium studies were performed under similar conditions in p53 deficient L5189Y and p53 proficient TK-6 cell lines, considerable differences were evident at the individual gene level.…”

“…The general availability of RT-PCR reagents for a majority of genes in the form of single gene assays or arrays of assays on card-like matrices have enabled the design of custom RT-PCR arrays consisting of specific genes of interest. For instance, RT-PCR has successfully been used to examine toxicant-induced CYP gene expression changes in hepatocytes (Bowen et al 2000), and cytokine expression in mouse and human cells (Kruse et al 1997;Hartel et al 1999;Overbergh et al 1999) and confirm microarray results (Islaih et al 2004). …”

Evidence that aberrant protein metabolism contributes to chemoresistance in multiple myeloma cells

“…5 indicates that global protein degradation is linear over this time period for treated and untreated CCL-155 cultures and that treatment with 0.05% MMS results in a significant decrease in the rate of protein degradation (P<0.05 at 1 h). This is a relatively low MMS dose compared to doses used for transcriptional profiling experiments for human cells (45). Nonetheless, this dose causes a 2-fold reduction in the rate of protein degradation compared to the untreated sample.…”