Impact of prenatal arsenate exposure on gene expression in a pure population of migratory cranial neural crest cells

MicroRNA-Gene Interactions Impacted by Toxic Metal(oid)s during EMT and Carcinogenesis

Chronic environmental exposure to toxic metal(loid)s significantly contributes to human cancer development and progression. It is estimated that approximately 90% of cancer deaths are a result of metastasis of malignant cells, which is initiated by epithelial-mesenchymal transition (EMT) during early carcinogenesis. EMT is regulated by many families of genes and microRNAs (miRNAs) that control signaling pathways for cell survival, death, and/or differentiation. Recent mechanistic studies have shown that toxic metal(loid)s alter the expression of miRNAs responsible for regulating the expression of genes involved in EMT. Altered miRNA expressions have the potential to be biomarkers for predicting survival and responses to treatment in cancers. Significantly, miRNAs can be developed as therapeutic targets for cancer patients in the clinic. In this mini review, we summarize key findings from recent studies that highlight chemical-miRNA-gene interactions leading to the perturbation of EMT after exposure to toxic metal(loid)s including arsenic, cadmium, nickel, and chromium.

Complex Elucidation of Cells-of-Origin in Pediatric Soft Tissue Sarcoma: From Concepts to Real Life, Hide-and-Seek through Epigenetic and Transcriptional Reprogramming

Soft tissue sarcoma (STS) comprise a large group of mesenchymal malignant tumors with heterogeneous cellular morphology, proliferative index, genetic lesions and, more importantly, clinical features. Full elucidation of this wide diversity remains a central question to improve their therapeutic management and the identity of cell(s)-of-origin from which these tumors arise is part of this enigma. Cellular reprogramming allows transitions of a mature cell between phenotypes, or identities, and represents one key driver of tumoral heterogeneity. Here, we discuss how cellular reprogramming mediated by driver genes in STS can profoundly reshape the molecular and morphological features of a transformed cell and lead to erroneous interpretation of its cell-of-origin. This review questions the fact that the epigenetic context in which a genetic alteration arises has to be taken into account as a key determinant of STS tumor initiation and progression. Retracing the cancer-initiating cell and its clonal evolution, notably via epigenetic approach, appears as a key lever for understanding the origin of these tumors and improving their clinical management.

Nucleic acid methylation and orofacial morphogenesis

In this review, we highlight the current state of knowledge of the diverse roles nucleic acid methylation plays in the embryonic development of the orofacial region and how aberrant methylation may contribute to orofacial clefts. We also consider the role of methylation in the regulation of neural crest cell function as it pertains to orofacial ontogeny. Changes in DNA methylation, as a consequence of environmental effects, have been observed in the regulatory regions of several genes, potentially identifying new candidate genes for orofacial clefting and opening promising new avenues for further research. While the focus of this review is primarily on the nonsyndromic forms of orofacial clefting, syndromic forms are briefly discussed in the context of aberrant nucleic acid methylation.