Histone deacetylase inhibitors VPA and TSA induce apoptosis and autophagy in pancreatic cancer cells.
OBJECTIVE
Histone deacetylase inhibitors (HDACi) are anti-neoplastic agents that are known to affect the growth of different cancer types, but their underlying mechanisms are still incompletely understood. Here, we compared the effects of two HDACi, i.e., Trichostatin A (TSA) and Valproic Acid (VPA), on the induction of cell death and autophagy in pancreatic cancer-derived cells that exhibit a high metastatic capacity and carry KRAS/p53 double mutations.


METHODS
Cell viability and proliferation tests were carried out using Trypan blue dye exclusion, MTT and BrdU assays. FACS analyses were carried out to assess cell cycle progression, apoptosis, reactive oxygen species (ROS) production and mitochondrial depolarization, while Western blot and immunoprecipitation analyses were employed to detect proteins involved in apoptosis and autophagy.


RESULTS
We found that both VPA and TSA can induce apoptosis in Panc1 and PaCa44 pancreatic cancer-derived cells by triggering mitochondrial membrane depolarization, Cytochrome c release and Caspase 3 activation, although VPA was more effective than TSA, especially in Panc1 cells. As underlying molecular events, we found that ERK1/2 was de-phosphorylated and that the c-Myc and mutant p53 protein levels were reduced after VPA and, to a lesser extent, after TSA treatment. Up-regulation of p21 and Puma was also observed, concomitantly with mutant p53 degradation. In addition, we found that in both cell lines VPA increased the pro-apoptotic Bim level, reduced the anti-apoptotic Mcl-1 level and increased ROS production and autophagy, while TSA was able to induce these effects only in PaCA44 cells.


CONCLUSIONS
From our results we conclude that both VPA and TSA can induce pancreatic cancer cell apoptosis and autophagy. VPA appears have a stronger and broader cytotoxic effect than TSA and, thus, may represent a better choice for anti-pancreatic cancer therapy.
Department of Experimental Medicine, La Sapienza University of Rome, V.le Regina Elena 324, 00161, Rome, Italy.
Maria Saveria
MS
Gilardini Montani
Department of Experimental Medicine, La Sapienza University of Rome, V.le Regina Elena 324, 00161, Rome, Italy.
Marisa
M
Granato
Department of Ecological and Biological Sciences (DEB), Tuscia University, Viterbo, Italy.
Claudio
C
Santoni
Department of Biology and Biotechnology 'Charles Darwin', La Sapienza University of Rome, Rome, Italy.
Paola
P
Del Porto
Department of Ecological and Biological Sciences (DEB), Tuscia University, Viterbo, Italy.
Nicolò
N
Merendino
Department of Research, Advanced Diagnostic and Technological Innovation, Regina Elena National Cancer Institute, Rome, Italy.|Department of Medical Sciences, Tumor Biology Unit, University "G. D'Annunzio", Chieti, Italy.
Gabriella
G
D'Orazi
Department of Experimental Medicine, La Sapienza University of Rome, V.le Regina Elena 324, 00161, Rome, Italy. alberto.faggioni@uniroma1.it.
Alberto
A
Faggioni
Department of Experimental Medicine, La Sapienza University of Rome, V.le Regina Elena 324, 00161, Rome, Italy. mara.cirone@uniroma1.it.
Mara
M
Cirone
D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D000069286:Bortezomib / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D050505:Mutant Proteins / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000473:pathology*; D010766:Phosphorylation / Q000187:drug effects; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014635:Valproic Acid / Q000494:pharmacology*
D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D050505:Mutant Proteins; D016271:Proto-Oncogene Proteins c-myc; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; C012589:trichostatin A; D014635:Valproic Acid; D000069286:Bortezomib; D048049:Extracellular Signal-Regulated MAP Kinases
Apoptosis; Autophagy; ERK; HDACi; Pancreatic cancer; ROS; TSA; VPA; p53