Epigenetic Influences in the Obesity/Colorectal Cancer Axis: A Novel Theragnostic Avenue

Abstract

The World Health Organization (WHO) considers that obesity has reached proportions of pandemic. Experts also insist on the importance of considering obesity as a chronic disease and one of the main contributors to the worldwide burden of other nontransmissible chronic diseases, which have a great impact on health, lifestyle, and economic cost. One of the most current challenges of biomedical science faces is to understand the origin of the chronic nontransmissible diseases, such as obesity and cancer. There is a large evidence, both in epidemiological studies in humans and in animal models, of the association between obesity and an increased risk of cancer incidence. In the last years, the initial discovery of epigenetic mechanisms represents the most relevant finding to explain how the genome interacts with environmental factors and the ripple effects on disease pathogeneses. Since then, all epigenetic process has been investigated by the scientific communities for nearly two decades to determine which components are involved in this process. DNA/RNA methylation and miRNA are classified as two of the most important representative classes of such epigenetic mechanisms and dysregulated activity of such mechanism can certainly contribute to disease pathogenesis and/or progression especially in tumors. This review article serves to highlight the impact of DNA/RNA methylation and miRNA-based epigenetic mechanism activities in the interplay between obesity and the development and clinical significance of colorectal cancer.

Figure 1

Proposed mechanisms linking FTO gene, obesity, and cancer. The weight gain, malfunctioning of the FTO gene leading to increase food intake and adipogenesis process could develop obesity, especially abdominal obesity. It is also linked to adipocyte hypertrophy and hypoxia. The hypertrophied adipose tissue acquires endocrine characteristics like fibroblasts, which produce an increase of adipokine and hormone secretion profile, proteases, and free fatty acids that may promote the stimulation of a microenvironment favorable for not only tumorigenesis, but acquire new properties as invasiveness and aggression. Abbreviations: m6A: N6-Methyladenosine; NPY: Neuropeptide Y; DRD3: Dopamine Receptor type D3; FTO: Fat-mass and obesity-associated; SNP: Single-nucleotide polymorphism; IL6: Interleukin 6.