Rapha Myr®, a Blend of Sulforaphane and Myrosinase, Exerts Antitumor and Anoikis-Sensitizing Effects on Human Astrocytoma Cells Modulating Sirtuins and DNA Methylation.

Barbara Tomasello,Giuseppe Antonio Malfa,Ignazio Alberto Barbagallo,Rosaria Acquaviva,Giusy Villaggio,Claudia Di Giacomo,Anna Bielak-Zmijewska,Wioleta Grabowska,Massimo Bonucci,Maria Domenica Di Mauro,Marcella Renis,Fulvia Sinatra,Maria Teresa Liuzzo,Samuele Laudani,Giorgia Spampinato,Elisabetta Sbisà,Maria Grazia Forte

doi:10.3390/ijms21155328

Abstract

Brain and other nervous system cancers are the 10th leading cause of death worldwide. Genome instability, cell cycle deregulation, epigenetic mechanisms, cytoarchitecture disassembly, redox homeostasis as well as apoptosis are involved in carcinogenesis. A diet rich in fruits and vegetables is inversely related with the risk of developing cancer. Several studies report that cruciferous vegetables exhibited antiproliferative effects due to the multi-pharmacological functions of their secondary metabolites such as isothiocyanate sulforaphane deriving from the enzymatic hydrolysis of glucosinolates. We treated human astrocytoma 1321N1 cells for 24 h with different concentrations (0.5, 1.25 and 2.5% v/v) of sulforaphane plus active myrosinase (Rapha Myr®) aqueous extract (10 mg/mL). Cell viability, DNA fragmentation, PARP-1 and γH2AX expression were examined to evaluate genotoxic effects of the treatment. Cell cycle progression, p53 and p21 expression, apoptosis, cytoskeleton morphology and cell migration were also investigated. In addition, global DNA methylation, DNMT1 mRNA levels and nuclear/mitochondrial sirtuins were studied as epigenetic biomarkers. Rapha Myr® exhibited low antioxidant capability and exerted antiproliferative and genotoxic effects on 1321N1 cells by blocking the cell cycle, disarranging cytoskeleton structure and focal adhesions, decreasing the integrin α5 expression, renewing anoikis and modulating some important epigenetic pathways independently of the cellular p53 status. In addition, Rapha Myr® suppresses the expression of the oncogenic p53 mutant protein. These findings promote Rapha Myr® as a promising chemotherapeutic agent for integrated cancer therapy of human astrocytoma.

Highlights

IntroductionAnaplastic astrocytomas and glioblastomas (GBM) represent the most frequent and aggressive primary malignancies of the central nervous system
The strategies involved in the prevention, progression, remission and relapse of cancer represent the key priority aims in public health worldwide [1,2].Anaplastic astrocytomas and glioblastomas (GBM) represent the most frequent and aggressive primary malignancies of the central nervous system
We investigated the anticancer activity of Rapha Myr®, demonstrating that Rapha Myr® elicited antiproliferative effects by inducing cell cycle arrest, oxidative stress and genotoxicity accompanied by global DNA hypermethylation and increased levels of DNA methyltransferase 1 (DNMT1), and changes in sirtuins’ expression and activity

Summary

Introduction

Anaplastic astrocytomas and glioblastomas (GBM) represent the most frequent and aggressive primary malignancies of the central nervous system. They are incurable diseases due mostly to their highly invasive phenotype, and the poor efficiency of the available therapies further reduced by the blood brain barrier that limits the delivery of drugs into the brain. The hallmarks of tumorigenesis and cancer progression are genetic instability, deregulation of epigenetic mechanisms, oxidative homeostasis, cell cycle progression, tumor microenvironment, and cell death program activation (e.g., the apoptotic cascade) [4]. Cell-specific activation of Integrins and their downstream signaling mediators are responsible for anoikis protection by transducing signals, which are necessary for cell proliferation, survival and migration, from the extracellular matrix (ECM) to the cell [5,6]. Anoikis obtained by unligated integrin-induced caspase 8 activation prevents metastasis and the caspase-8 suppression is associated with increased invasive capacity in vivo [7]

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