The role of the alternate G protein–coupled estrogen receptor 1 (GPER1) in colorectal cancer (CRC) development and progression is unclear, not least because of conflicting clinical and experimental evidence for pro- and anti-tumorigenic activities. Here, we show that low concentrations of the estrogenic GPER1 ligands, 17β-estradiol, bisphenol A, and diethylstilbestrol cause the generation of lagging chromosomes in normal colon and CRC cell lines, which manifest in whole chromosomal instability and aneuploidy. Mechanistically, (xeno)estrogens triggered centrosome amplification by inducing centriole overduplication that leads to transient multipolar mitotic spindles, chromosome alignment defects, and mitotic laggards. Remarkably, we could demonstrate a significant role of estrogen-activated GPER1 in centrosome amplification and increased karyotype variability. Indeed, both gene-specific knockdown and inhibition of GPER1 effectively restored normal centrosome numbers and karyotype stability in cells exposed to 17β-estradiol, bisphenol A, or diethylstilbestrol. Thus, our results reveal a novel link between estrogen-activated GPER1 and the induction of key CRC-prone lesions, supporting a pivotal role of the alternate estrogen receptor in colon neoplastic transformation and tumor progression.

Current animal protection laws require replacement of animal experiments with alternative methods, whenever such methods are suitable to reach the intended scientific objective. However, searching for alternative methods in the scientific literature is a time-consuming task that requires careful screening of an enormously large number of experimental biomedical publications. The identification of potentially relevant methods, e.g. organ or cell culture models, or computer simulations, can be supported with text mining tools specifically built for this purpose. Such tools are trained (or fine tuned) on relevant data sets labeled by human experts. We developed the GoldHamster corpus, composed of 1,600 PubMed (Medline) articles (titles and abstracts), in which we manually identified the used experimental model according to a set of eight labels, namely: “in vivo”, “organs”, “primary cells”, “immortal cell lines”, “invertebrates”, “humans”, “in silico” and “other” (models). We recruited 13 annotators with expertise in the biomedical domain and assigned each article to two individuals. Four additional rounds of annotation aimed at improving the quality of the annotations with disagreements in the first round. Furthermore, we conducted various machine learning experiments based on supervised learning to evaluate the corpus for our classification task. We obtained more than 7,000 document-level annotations for the above labels. After the first round of annotation, the inter-annotator agreement (kappa coefficient) varied among labels, and ranged from 0.42 (for “others”) to 0.82 (for “invertebrates”), with an overall score of 0.62. All disagreements were resolved in the subsequent rounds of annotation. The best-performing machine learning experiment used the PubMedBERT pre-trained model with fine-tuning to our corpus, which gained an overall f-score of 0.83. We obtained a corpus with high agreement for all labels, and our evaluation demonstrated that our corpus is suitable for training reliable predictive models for automatic classification of biomedical literature according to the used experimental models. Our SMAFIRA - “Smart feature-based interactive” - search tool (https://smafira.bf3r.de) will employ this classifier for supporting the retrieval of alternative methods to animal experiments. The corpus is available for download (https://doi.org/10.5281/zenodo.7152295), as well as the source code (https://github.com/mariananeves/goldhamster) and the model (https://huggingface.co/SMAFIRA/goldhamster).

Estrogens are associated with a variety of diseases and play important roles in tumor development and progression. Centrosome defects are hallmarks of human cancers and contribute to ongoing chromosome missegragation and aneuploidy that manifest in genomic instability and tumor progression. Although several mechanisms underlie the etiology of centrosome aberrations in human cancer, upstream regulators are hardly known. Accumulating experimental and clinical evidence points to an important role of estrogens in deregulating centrosome homeostasis and promoting karyotype instability. Here, we will summarize existing literature of how natural and synthetic estrogens might contribute to structural and numerical centrosome defects, genomic instability and human carcinogenesis.

Cancer is a major health concern and a leading cause of mortality. The reliable identification of carcinogens and understanding of carcinogenicity has become a main focus of biomedical research and regulatory toxicology. While biomedical research applies cellular in vitro methods to uncover the underlying mechanisms causing cancer, regulatory toxicology relies on animal testing to predict carcinogenicity of chemicals, often with limited human relevance. Exemplified by chromosome instability–mediated carcinogenicity, we discuss the need to combine the strengths of both fields to develop highly predictive and mechanism-derived in vitro methods that facilitate risk assessment in respect to relevant human diseases.

Although chromosomal instability (CIN) is a recognized hallmark of cancer the underlying mechanisms and consequences are largely unknown. However, it is accepted that lagging chromosomes represent a major prerequisite for chromosome missegregation in cancer cells. Here, we discuss how lagging chromosomes are generated and our recent findings establishing increased microtubule assembly rates as a source of CIN.

Centrosome amplification is a hallmark of colorectal cancer (CRC), yet its molecular origins remain elusive. Protein Kinase A (PKA), anchored to centrosomes, regulates a number of mitotic processes, though its role in maintaining centrosome integrity remains poorly understood. Here, we show that PKA is central to a signaling cascade involving the G protein-coupled estrogen receptor GPER1, which is essential for centrosome integrity in colon cancer cells. Activation of GPER1 by estrogens or a specific agonist triggers Gαs protein-mediated stimulation of adenylyl cyclase, elevating cAMP levels and thereby increasing PKA activity. Excessive activation of GPER1-PKA leads to extra centrosomes with enlarged, displaced Centrin-2 foci . Recruited to centrosomes by AKAP450, PKA phosphorylates Centrin-2, predominantly at aberrant centrioles and unexpectedly even outside of mitosis. These findings reveal a GPER1-PKA-Centrin signaling axis in CRC cells that regulates centrosome numbers and centriole integrity, shedding light on centrosome abnormalities that drive neoplastic transformation and tumor progression.