Epigenetic drugs as pleiotropic agents in cancer treatment: biomolecular aspects and clinical applications.
In the last three decades huge efforts have been made to characterize genetic defects responsible for cancer development and progression, leading to the comprehensive identification of distinct cellular pathways affected by the alteration of specific genes. Despite the undoubtable role of genetic mechanisms in triggering neoplastic cell transformation, epigenetic modifications (i.e., heritable changes of gene expression that do not derive from alterations of the nucleotide sequence of DNA) are rapidly emerging as frequent alterations that often occur in the early phases of tumorigenesis and that play an important role in tumor development and progression. Epigenetic alterations, such as modifications in DNA methylation patterns and post-translational modifications of histone tails, behave extremely different from genetic modifications, being readily revertable by "epigenetic drugs" such as inhibitors of DNA methyl transferases and inhibitors of histone deacetylases. Since epigenetic alterations in cancer cells affect virtually all cellular pathways that have been associated to tumorigenesis, it is not surprising that epigenetic drugs display pleiotropic activities, being able to concomitantly restore the defective expression of genes involved in cell cycle control, apoptosis, cell signaling, tumor cell invasion and metastasis, angiogenesis and immune recognition. Prompted by this emerging clinical relevance of epigenetic drugs, this review will focus on the large amount of available data, deriving both from in vitro experimentations and in vivo pre-clinical and clinical studies, which clearly indicate epigenetic drugs as effective modifiers of cancer phenotype and as positive regulators of tumor cell biology with a relevant therapeutic potential in cancer patients.
Sigalotti
Luca
L
Cancer Bioimmunotherapy Unit, Department of Medical Oncology, Centro di Riferimento Oncologico, Istituto di Ricovero e Cura a Carattere Scientifico, Aviano, Italy.
Fratta
Elisabetta
E
Coral
Sandra
S
Cortini
Enzo
E
Covre
Alessia
A
Nicolay
Hugues J M
HJ
Anzalone
Lucia
L
Pezzani
Laura
L
Di Giacomo
Anna Maria
AM
Fonsatti
Ester
E
Colizzi
Francesca
F
Altomonte
Maresa
M
Calabrò
Luana
L
Maio
Michele
M
D000107:Acetylation; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D019175:DNA Methylation / Q000187:drug effects; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D044127:Epigenesis, Genetic / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D009361:Neoplasm Invasiveness; D009369:Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D019139:Tumor Escape / Q000187:drug effects / Q000235:genetics
D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D015254:DNA Modification Methylases; D006655:Histone Deacetylases