Sulforaphane and iberin are potent epigenetic modulators of histone acetylation and methylation in malignant melanoma.

OBJECTIVE(S): Growing evidence supports that isothiocyanates exert a wide range of bioactivities amongst of which is their capacity to interact with the epigenetic machinery in various cancers including melanoma. Our aim was to characterise the effect of sulforaphane and iberin on histone acetylation and methylation as a potential anti-melanoma strategy. METHODS: We have utilised an in vitro model of malignant melanoma [consisting of human (A375, Hs294T, VMM1) and murine (B16F-10) melanoma cell lines as well as a non-melanoma (A431) and a non-tumorigenic immortalised keratinocyte (HaCaT) cell line] exposed to sulforaphane or iberin. Cell viability was evaluated by the Alamar blue assay whilst total histone deacetylases and acetyltransferases activities were determined by the Epigenase HDAC Activity/Inhibition and EpiQuik HAT Activity/Inhibition assay kits, respectively. The expression levels of specific histone deacetylases and acetyltransferases together with those of lysine acetylation and methylation marks were obtained by western immunoblotting. RESULTS: Overall, both sulforaphane and iberin were able to (1) reduce cell viability, (2) decrease total histone deacetylase activity and (3) modulate the expression levels of various histone deacetylases as well as acetyl and methyl transferases thus modulating the acetylation and methylation status of specific lysine residues on histones 3 and 4 in malignant melanoma cells. CONCLUSIONS: Our findings highlight novel insights as to how sulforaphane and iberin differentially regulate the epigenetic response in ways compatible with their anticancer action in malignant melanoma.

Allyl isothiocyanate regulates lysine acetylation and methylation marks in an experimental model of malignant melanoma.

OBJECTIVE(S): Isothiocyanates (ITCs) are biologically active plant secondary metabolites capable of mediating various biological effects including modulation of the epigenome. Our aim was to characterize the effect of allyl isothiocyanate (AITC) on lysine acetylation and methylation marks as a potential epigenetic-induced anti-melanoma strategy. METHODS: Our malignant melanoma model consisted of (1) human (A375) and murine (B16-F10) malignant melanoma as well as of human; (2) brain (VMM1) and lymph node (Hs 294T) metastatic melanoma; (3) non-melanoma epidermoid carcinoma (A431) and (4) immortalized keratinocyte (HaCaT) cells subjected to AITC. Cell viability, histone deacetylases (HDACs) and acetyltransferases (HATs) activities were evaluated by the Alamar blue, Epigenase HDAC Activity/Inhibition and EpiQuik HAT Activity/Inhibition assay kits, respectively, while their expression levels together with those of lysine acetylation and methylation marks by western immunoblotting. Finally, apoptotic gene expression was assessed by an RT-PCR-based gene expression profiling methodology. RESULTS: AITC reduces cell viability, decreases HDACs and HATs activities and causes changes in protein expression levels of various HDACs, HATs, and histone methyl transferases (HMTs) all of which have a profound effect on specific lysine acetylation and methylation marks. Moreover, AITC regulates the expression of a number of genes participating in various apoptotic cascades thus indicating its involvement in apoptotic induction. CONCLUSIONS: AITC exerts a potent epigenetic effect suggesting its potential involvement as a promising epigenetic-induced bioactive for the treatment of malignant melanoma.

Synergistic Antitumor Potency of a Self-Assembling Peptide Hydrogel for the Local Co-delivery of Doxorubicin and Curcumin in the Treatment of Head and Neck Cancer.

Combination therapy has been conferred with manifold assets leveraging the synergy of different agents to achieve a sufficient therapeutic outcome with lower administered drug doses and reduced side effects. The therapeutic potency of a self-assembling peptide hydrogel for the co-delivery of doxorubicin and curcumin was assessed against head and neck cancer cells. The dual loaded peptide hydrogel enabled control over the rate of drug release based on drug's aqueous solubility. A significantly enhanced cell growth inhibitory effect was observed after treatment with the combination drug-loaded hydrogel formulations compared to the respective combination drug solution. The synergistic pharmacological effect of selected hydrogel formulations was further confirmed with enhanced apoptotic cell response, interference in cell cycle progression, and significantly altered apoptotic/anti-apoptotic gene expression profiles obtained in dose levels well below the half-maximal inhibitory concentrations of both drugs. The in vivo antitumor efficacy of the drug-loaded peptide hydrogel formulation was confirmed in HSC-3 cell-xenografted severe combined immunodeficient mice and visualized with µCT imaging. Histological and terminal deoxynucleotidyl transferase dUTP nick end labeling assay analyses of major organs were implemented to assess the safety of the topically administered hydrogel formulation. Overall, results demonstrated the therapeutic utility of the dual drug-loaded peptide hydrogel as a pertinent approach for the local treatment of head and neck cancer.

The Role of Isothiocyanates as Cancer Chemo-Preventive, Chemo-Therapeutic and Anti-Melanoma Agents.

Many studies have shown evidence in support of the beneficial effects of phytochemicals in preventing chronic diseases, including cancer. Among such phytochemicals, sulphur-containing compounds (e.g., isothiocyanates (ITCs)) have raised scientific interest by exerting unique chemo-preventive properties against cancer pathogenesis. ITCs are the major biologically active compounds capable of mediating the anticancer effect of cruciferous vegetables. Recently, many studies have shown that a higher intake of cruciferous vegetables is associated with reduced risk of developing various forms of cancers primarily due to a plurality of effects, including (i) metabolic activation and detoxification, (ii) inflammation, (iii) angiogenesis, (iv) metastasis and (v) regulation of the epigenetic machinery. In the context of human malignant melanoma, a number of studies suggest that ITCs can cause cell cycle growth arrest and also induce apoptosis in human malignant melanoma cells. On such basis, ITCs could serve as promising chemo-therapeutic agents that could be used in the clinical setting to potentiate the efficacy of existing therapies.

From chemo-prevention to epigenetic regulation: The role of isothiocyanates in skin cancer prevention.

Skin cancer incidence is rapidly growing over the last decades and is generally divided into malignant melanoma and non-melanoma (NMSC) with the latter being subdivided into squamous (SCC) and basal cell carcinoma (BCC). Among them, melanoma is the most aggressive type with high mortality rates. On the other hand, aberrant gene expression is a critical step towards malignant transformation. To this end, epigenetic modifications like changes in DNA methylation patterns and miRNA expression profile as well as histone modifications are all capable of inducing an altered gene expression profile involved in various cellular cascades including cell cycle, proliferation and apoptosis. In general, there is an interest about the beneficiary effect of various phytochemicals in the prevention and treatment of skin malignancies. Among them, glucosinolates are an important type of compounds, abundant in cruciferous vegetables, which are hydrolysed by an endogenous enzyme called myrosinase to a range of bioactive compounds including isothiocyanates (ITCs). These are the major biologically active products capable of mediating the anti-cancer effect of cruciferous vegetables. Their chemo-preventive action is mainly attributed to a plurality of anti-cancer properties including regulation of the epigenetic machinery. Current evidence supports the view that ITCs are potent compounds in interacting with the epigenome in order to restore the normal epigenetic landscape in malignant cells. This review article summarizes the current state of knowledge on the epigenetic modifications that lead to malignant transformation and the role of ITCs with respect to their ability to restore the epigenetic landscape that contributes to skin carcinogenesis.

The molecular basis of fertilization (Review).

Fertilization is the fusion of the male and female gamete. The process involves the fusion of an oocyte with a sperm, creating a single diploid cell, the zygote, from which a new individual organism will develop. The elucidation of the molecular mechanisms of fertilization has fascinated researchers for many years. In this review, we focus on this intriguing process at the molecular level. Several molecules have been identified to play a key role in each step of this intriguing process (the sperm attraction from the oocyte, the sperm maturation, the sperm and oocyte fusion and the two gamete pronuclei fusion leading to the zygote). Understanding the molecular mechanisms of the cell­cell interactions will provide a better understanding of the causes of fertility issues due to fertilization defects.