[Master and servant: epigenetic deregulations as a cause and a consequence of cancer]

Antioxidant and Anti-inflammatory Properties of the Two Varieties of Musa acuminata: An In Vitro Study

Background Free radicals are involved in the process of carcinogenesis. Conventional antioxidants and anti-inflammatory drugs have the disadvantages of side effects and high costs. Banana peel contains phenolic and non-phenolic antioxidants that are pivotal in removing inflammatory components by inhibiting reactive oxygen species (ROS), protecting protease inhibitors from oxidative damage, and preventing fibroblast degradation which protects the body against the ill effects of free radicals. Aim and objectives The present study aimed to evaluate the potential antioxidant and anti-inflammatory activity of peel extracts of the Musa acuminata Red Dacca(red banana) and Musa acuminata Colla (rasthali). Materials and methods The procured unripe peels of red bananas and rasthali bananas were dried, ground into powder, and used to create aqueous and alcoholic extracts. The aqueous extract was made by dissolving 5 grams of peel powder in 25 ml of distilled water, while the alcoholic extract was prepared by heating ethanol to 100°C for 30 minutes. The extracts were combined, shaken for 24 hours, filtered, and stored at 4°C. Following extract preparation, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, hydrogen peroxide (H2O2) assay, bovine serum albumin (BSA) denaturation assay, and egg albumin (EA) denaturation assay were performed to evaluate the antioxidant and anti-inflammatory properties. The assays were performed in varying concentrations for the prepared extracts of red banana and rasthali and the 1:1 ratio combination extract of both varieties. The obtained data were tabulated and statistically tested using the IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, New York, United States) by the Kruskal-Wallis test with the statistical significance set at p≤0.05. Results Results highlighted variations in the antioxidant and anti-inflammatory properties of the banana peel extracts and the standard used in all the assays, but there was no statistically significant difference between the extracts and the standard (p>0.05). There was an increase in the antioxidant and anti-inflammatory activity with an increase in the concentration of both the extracts and the standard. The 1:1 ratio combination extract showed the highest antioxidant property among the banana extracts in the majority of the concentrations in the DPPH assay, whereas the rasthali extract showed the same even more than the standard in the H2O2 assay. The rasthali extract showed the highest anti-inflammatory property in all the concentrations in the BSA assay, and the 1:1 ratio combination extract showed the same in the EA assay. Conclusion The banana peel extracts showed comparable antioxidant and anti-inflammatory properties with that of the standard in all the assays with no statistically significant difference. There was a rising trend in the properties with an increase in their concentration. Red banana and rasthali peel extracts, either individually or in combination, could be a promising, effective, and cost-effective alternative or adjunct to the currently available antioxidant medications.

[Epigenetics and oncology: Two faces of the personalization of medicine]

In this article, we outline the two dominant concepts of personalized medicine put forward by epigenetics in the field of oncology. First, knowledge on the molecular processes involved in tumor progression contributes to molecularize medicine, extending genomic medicine. Then, the identification of epigenetic mechanisms underlying the environmental causes of cancers brings scientific legitimacy to products and services whose advertising promotes the ability of each person to protect herself from cancer by adapting her lifestyle. Lastly, we argue that research in environmental epigenetics could open a new route for personalized medicine in oncology, where epigenetics contributes to an individualized assessment of patients' life paths.

The Role of Epigenetic Modifications in Human Cancers and the Use of Natural Compounds as Epidrugs: Mechanistic Pathways and Pharmacodynamic Actions

Cancer is a complex disease resulting from the genetic and epigenetic disruption of normal cells. The mechanistic understanding of the pathways involved in tumor transformation has implicated a priori predominance of epigenetic perturbations and a posteriori genetic instability. In this work, we aimed to explain the mechanistic involvement of epigenetic pathways in the cancer process, as well as the abilities of natural bioactive compounds isolated from medicinal plants (flavonoids, phenolic acids, stilbenes, and ketones) to specifically target the epigenome of tumor cells. The molecular events leading to transformation, angiogenesis, and dissemination are often complex, stochastic, and take turns. On the other hand, the decisive advances in genomics, epigenomics, transcriptomics, and proteomics have allowed, in recent years, for the mechanistic decryption of the molecular pathways of the cancerization process. This could explain the possibility of specifically targeting this or that mechanism leading to cancerization. With the plasticity and flexibility of epigenetic modifications, some studies have started the pharmacological screening of natural substances against different epigenetic pathways (DNA methylation, histone acetylation, histone methylation, and chromatin remodeling) to restore the cellular memory lost during tumor transformation. These substances can inhibit DNMTs, modify chromatin remodeling, and adjust histone modifications in favor of pre-established cell identity by the differentiation program. Epidrugs are molecules that target the epigenome program and can therefore restore cell memory in cancerous diseases. Natural products isolated from medicinal plants such as flavonoids and phenolic acids have shown their ability to exhibit several actions on epigenetic modifiers, such as the inhibition of DNMT, HMT, and HAT. The mechanisms of these substances are specific and pleiotropic and can sometimes be stochastic, and their use as anticancer epidrugs is currently a remarkable avenue in the fight against human cancers.

Cancer Preventive and Therapeutic Potential of Banana and Its Bioactive Constituents: A Systematic, Comprehensive, and Mechanistic Review

Background

The banana (Musa spp.) plant produces elongated and edible fruit. The two main parthenocarpic species of banana are Musa accuminata Colla and Musa balbisiana Colla. There are several health-promoting and disease-preventing effects of Musa accuminata Colla, which are attributed to its important bioactive compounds, including phenolics, carotenoids, biogenic amines, phytosterols, and volatile oils, found in the stem, fruit, pseudostem, leaf, flower, sap, inner trunk, root, and inner core. Banana possesses numerous pharmacological activities, such as antioxidant, immunomodulatory, antimicrobial, antiulcerogenic, hypolipidemic, hypoglycemic, leishmanicidal, anthelmintic, and anticancer properties. Various individual studies have reported anticancer effects of different components of the banana plant. However, according to our understanding, an up-to-date, systematic, and critical analysis of existing scientific results has not yet been carried out.

Objectives

This review aims to include a thorough assessment of banana and its phytochemicals for cancer prevention and therapy with a focus on cellular and molecular mechanisms of action.

Methods

The available research studies on anticancer activities of banana extracts, fractions and pure compounds were collected using various scholarly databases, such as PubMed, ScienceDirect, and Scopus, based on predetermined selection criteria.

Results

Various banana extracts, fractions, and phytoconstituents, including ferulic acid, protocatechualdehyde, 2-pentanone, 4-epicyclomusalenone, cycloeucalenol acetate, and chlorogenic acid, have been shown to exhibit cancer preventative and anticancer activities in breast, cervical, colorectal, esophageal, hepatic, oral, prostate, and skin cancers. Bioactive components present in bananas have exhibited antiproliferative, cell cycle arrest-inducing, apoptotic, anti-adhesive, anti-invasive, and antiangiogenic effects through modulation of diverse, dysregulated oncogenic signaling pathways.

Conclusion

Based on the critical analysis of available literature, banana products and phytoconstituents show enormous potential for future development of drugs for cancer prevention and therapy. However, more mechanistic studies and well-designed clinical trials should be performed to establish its efficacy.

[Epigenetic perturbations and cancer: innovative therapeutic strategies against cancer]

A complex system of molecular milestones ensures labelling of the genome, driving its organization and functions. These milestones correspond to particular marks associated to active and repressed genes, as well as to non-coding regions or those containing repetitive sequences. Most of these marks are chemical modifications of DNA, corresponding to cytosine methylation, or various posttranslational modifications of histones, the proteins which package the genome. These chemical modifications of DNA or histones are reversible and are catalysed and removed by enzymatic activities associated with factors ensuring critical cellular functions. Indeed, these enzymes are directly connected with signalling pathways, sensing extra- and intracellular environments. Altogether these mechanisms globally control the expression status of genes in each cell, meaning that certain genes are kept active, while most of the genome remains silent. Subtle metabolic changes or intra and extracellular modifications, by altering the marking associated to genes, can have long-term consequences on their expression status. Genes coding for essential regulators of cellular proliferation and differentiation could be among these genes, such as tumor suppressor genes for instance. Hence the knowledge of all these so-called "epigenetic" mechanisms will shed new light on the environmental impact on the control of gene expression and associated diseases, including malignant transformation. The understanding of these mechanisms will also pave the way for innovative therapeutic strategies to fight cancer. This review is aiming to give an overview to the reader of the relevance of epigenetic mechanisms for the understanding and treatment of cancer.

[Profiles of DNA methylation in normal and cancer cells]

In eukaryotes, the epigenetic mark DNA methylation is found exclusively at cytosine residues in the CpG islands of genes, transposons and intergenic DNA. Among functional roles, DNA methylation is essential for mammalian embryonic development, and is classically thought to function by stably silencing promoter activity. However, until recently, understanding of the distribution of cytosine methylation in the whole genome - and hence, identification of its targets - was very limited. High-throughput methodologies, including methylated DNA immunoprecipitation, have recently revealed genome-wide mapping of DNA methylation, and provided new and unexpected data. Clearly DNA methylation is selectively associated with some key promoters- and is not a prerequisite for promoter inactivation, since strong CpG island promoters are mostly unmethylated, even when inactive. Most germline-specific genes are methylated and permanently silenced in somatic cells, suggesting a role of this mark in maintaining somatic cellular identity. These large scale studies will also help understanding the deregulation of DNA methylation associated with cancer, among which unmethylation of germinal cells genes, and recent observtion of large hypomethylated regions in tumoral specimens. The next challenge will be to understand if these methylation changes occur randomly, or more likely are specified by oncogenes or linked to environmental pressure.