Comparative Toxicogenomics of Glyphosate and Roundup Herbicides by Mammalian Stem Cell-Based Genotoxicity Assays and Molecular Profiling in Sprague-Dawley Rats

Abstract

Whether glyphosate-based herbicides (GBHs) are more potent than glyphosate alone at activating cellular mechanisms, which drive carcinogenesis remains controversial. As GBHs are more cytotoxic that glyphosate, we reasoned they may also be more capable of activating carcinogenic pathways. We tested this hypothesis by comparing the effects of glyphosate with Roundup GBHs both in vitro and in vivo. First, glyphosate was compared with representative GBHs namely MON 52276 (EU), MON 76473 (UK) and MON 76207 (USA) using the mammalian stem cell-based ToxTracker system. Here, MON 52276 and MON 76473, but not glyphosate and MON 76207, activated oxidative stress and unfolded protein responses. Second, molecular profiling of liver was performed in female Sprague-Dawley rats exposed to glyphosate or MON 52276 (both at 0.5, 50, 175 mg/kg bw/day glyphosate) for 90 days. MON 52276 but not glyphosate increased hepatic steatosis and necrosis. MON 52276 and glyphosate altered the expression of genes in liver reflecting TP53 activation by DNA damage and circadian rhythm regulation. Genes most affected in liver were similarly altered in kidneys. Small RNA profiling in liver showed decreased amounts of miR-22 and miR-17 from MON 52276 ingestion. Glyphosate decreased mir-30 while miR-10 levels were increased. DNA methylation profiling of liver revealed 5,727 and 4,496 differentially methylated CpG sites between the control and glyphosate and MON 52276 exposed animals respectively. Apurinic/apyrimidinic DNA damage formation in liver was increased with glyphosate exposure. Altogether, our results show that Roundup formulations cause more biological changes linked with carcinogenesis than glyphosate.

Single-cell transcriptome analysis reveals liver injury induced by glyphosate in mice

“…In addition, upregulation of genes involved in ribonucleoprotein complex assembly and ribonucleoprotein complex subunit organization in both Hep1 and Hep2 suggests potential DNA damage of GLY (Fig. 3 E), which has been reported previously [ 23 ]. Overall, GLY may cause oxidative stress, abnormal lipid metabolism, inflammatory response, and DNA damage, suggesting GLY-induced dysregulation of hepatocytes.…”

“…Mesnage et al. observed activated oxidative stress (reflected by Srxn1 and Blvrb) in mammalian stem cell-based ToxTracker system by glyphosate-based herbicides but not glyphosate itself [ 23 ], In our study, the expression level of Srxn1 and Blvrb (Fig. 3 G and Additional file 2 : Table S9) was improved after GLY exposure.…”

“…GLY induced proliferation of T47D cells, a human hormone-dependent breast cancer cell line [ 20 ]. Besides, the adjuvants used to enhance water solubility and plant absorption of GLY are often detected in the environment and induce cell toxicity [ 21 – 23 ]. It was not quite clear how GLY degrades in mammals, but its metabolites such as aminomethylphosphonic acid (AMPA) were detected after GLY exposure in animals [ 24 – 26 ] and humans [ 27 ].…”

Direct Effects of Glyphosate on In Vitro T Helper Cell Differentiation and Cytokine Production

“…Supporting this evidence, more recently, perinatal G exposure in mice was associated with aberrant expression of lncRNAs, highlighting a link with impaired neuronal development ( 55 ). Also changes in miRNA profile in female rat liver were assessed following G and G-based herbicide treatment, and interestingly these miRNAs were associated with carcinogenesis, like miR-17 and miR-22 ( 56 ). Furthermore, an in vitro study performed on carp lymphocytes shown that G-induced lymphocyte apoptosis was mediated by the regulation of miR-203 and PI3K/AKT pathway ( 57 ).…”

Cytotoxic effects of Roundup Classic and its components on NE-4C and MC3T3-E1 cell lines determined by biochemical and flow cytometric assays

“…Polyethoxylated tallowamine (POE-15) is a main surfactant in herbicide Roundup Classic, the chemical acts as a tackifier by helping its adsorption on plant surfaces and uptake by plants, and it also facilitates its uptake to cells though disturbing membrane (cell wall) processes. Increased toxicity of POE-15-formulated GBHs compared to glyphosate has been documented in the scientific literature [47] , [48] , and POE-15 and other co-formulants alone also exerts numerous side effects, for example genotoxicity, cytotoxicity [28] , [47] , [49] , [50] , [51] , [52] , [53] . GBHs containing POE-15 were banned in the EU in 2016 [54] , and the ban was extended to polypropoxylated tallowamines and a number of other co-formulants in 2021 [55] .…”