Present state and future perspectives of using pluripotent stem cells in toxicology research

The use of novel drugs and chemicals requires reliable data on their potential toxic effects on humans. Current test systems are mainly based on animals or in vitro–cultured animal-derived cells and do not or not sufficiently mirror the situation in humans. Therefore, in vitro models based on human pluripotent stem cells (hPSCs) have become an attractive alternative. The article summarizes the characteristics of pluripotent stem cells, including embryonic carcinoma and embryonic germ cells, and discusses the potential of pluripotent stem cells for safety pharmacology and toxicology. Special attention is directed to the potential application of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) for the assessment of developmental toxicology as well as cardio- and hepatotoxicology. With respect to embryotoxicology, recent achievements of the embryonic stem cell test (EST) are described and current limitations as well as prospects of embryotoxicity studies using pluripotent stem cells are discussed. Furthermore, recent efforts to establish hPSC-based cell models for testing cardio- and hepatotoxicity are presented. In this context, methods for differentiation and selection of cardiac and hepatic cells from hPSCs are summarized, requirements and implications with respect to the use of these cells in safety pharmacology and toxicology are presented, and future challenges and perspectives of using hPSCs are discussed

An integrated inspection of the somatic mutations in a lung squamous cell carcinoma using next-generation sequencing

Squamous cell carcinoma (SCC) of the lung kills over 350,000 people annually worldwide, and is the main lung cancer histotype with no targeted treatments. High-coverage whole-genome sequencing of the other main subtypes, small-cell and adenocarcinoma, gave insights into carcinogenic mechanisms and disease etiology. The genomic complexity within the lung SCC subtype, as revealed by The Cancer Genome Atlas, means this subtype is likely to benefit from a more integrated approach in which the transcriptional consequences of somatic mutations are simultaneously inspected. Here we present such an approach: the integrated analysis of deep sequencing data from both the whole genome and whole transcriptome (coding and non-coding) of LUDLU-1, a SCC lung cell line. Our results show that LUDLU-1 lacks the mutational signature that has been previously associated with tobacco exposure in other lung cancer subtypes, and suggests that DNA-repair efficiency is adversely affected; LUDLU-1 contains somatic mutations in TP53 and BRCA2, allelic imbalance in the expression of two cancer-associated BRCA1 germline polymorphisms and reduced transcription of a potentially endogenous PARP2 inhibitor. Functional assays were performed and compared with a control lung cancer cell line. LUDLU-1 did not exhibit radiosensitisation or an increase in sensitivity to PARP inhibitors. However, LUDLU-1 did exhibit small but significant differences with respect to cisplatin sensitivity. Our research shows how integrated analyses of high-throughput data can generate hypotheses to be tested in the lab

Rare Cancers

According to IARC figures ‘rare and less common’ cancers comprise more than a third of all cancer diagnoses as a group. However, advances in molecular biology have resulted in novel ways to classify cancers based upon genetic alterations and not just anatomical location, and this revised classification is at the heart of any move toward more personalized healthcare. It is now increasingly accepted that cancer should be thought of as many hundreds of more rare subtypes, each of which will have specific therapeutic options. We have selected colorectal carcinoma to illustrate the concept that each cancer is ‘rare’, and demonstrate why this is important for delivering on the concept of Predictive, Preventive and Personalized Medicine (PPPM) for cancer in terms of prediction of who will get the disease, how it will behave and how to prevent it

Prevention of the neurocristopathy Treacher Collins syndrome through inhibition of p53 function

Treacher Collins syndrome (TCS) is a congenital disorder of craniofacial development arising from mutations in TCOF1, which encodes the nucleolar phosphoprotein Treacle. Haploinsufficiency of Tcof1 perturbs mature ribosome biogenesis, resulting in stabilization of p53 and the cyclin G1–mediated cell-cycle arrest that underpins the specificity of neuroepithelial apoptosis and neural crest cell hypoplasia characteristic of TCS. Here we show that inhibition of p53 prevents cyclin G1–driven apoptotic elimination of neural crest cells while rescuing the craniofacial abnormalities associated with mutations in Tcof1 and extending life span. These improvements, however, occur independently of the effects on ribosome biogenesis; thus suggesting that it is p53-dependent neuroepithelial apoptosis that is the primary mechanism underlying the pathogenesis of TCS. Our work further implies that neuroepithelial and neural crest cells are particularly sensitive to cellular stress during embryogenesis and that suppression of p53 function provides an attractive avenue for possible clinical prevention of TCS craniofacial birth defects and possibly those of other neurocristopathies

Reverse transcriptase activity and Ty RNA are associated with virus-like particles in yeast.

The Ty element of yeast represents a class of eukaryotic transposons that show remarkable structural similarity to retroviral proviruses. Recently, these comparisons have been strengthened by a series of observations on the yeast Ty element: Ty transposes via an RNA intermediate; it contains a sequence (Fig. 1) which, when translated, is homologous to a conserved region found in all reverse transcriptases; a fusion protein encoded by Ty is produced by a frameshift event that is directly analogous to the production of Pr180gag-pol in a retrovirus such as Rous sarcoma virus. Here we identify the reverse transcriptase activity that, until now, has been presumed to mediate Ty transposition and show that it is sequestered in virus-like particles that also contain Ty RNA