E2F1-dependent pathways are involved in amonafide analogue 7-d-induced DNA damage, G2/M arrest, and apoptosis in p53-deficient K562 cells.

Abstract

The E2F1 gene well known is its pivotal role in regulating the entry from G1 to S phase, while the salvage antitumoral pathway which implicates it, especially in the absence of p53, is not fully characterized. We therefore attempted to identify the up- and down-stream events involved in the activation of the E2F1-dependent pro-apoptotic pathway. For this purpose, a amonafide analogue, 7-d (2-(3-(2-(Dimethylamino)ethylamino)propyl)-6-(dodecylamino)-1H-benzo[de]isoquinoline-1,3(2H)-dione) was screened, which exhibited high antitumor activity against p53-deficient human Chronic Myelogenous Leukemia (CML) K562 cells. Analysis of flow cytometry and western blots of K562 cells treated with 7-d revealed an appreciable G2/M cycle arrest and apoptosis in a dose and time-dependent manner via p53-independent pathway. A striking increase in "Comet tail" formation and γ-H2AX expression showed that DNA double strand breaks (DSB) were caused by 7-d treatment. ATM/ATR signaling was reported to connect E2F1 induction with apoptosis in response to DNA damage. Indeed, 7-d-induced G2/M arrest and apoptosis were antagonized by ATM/ATR signaling inhibitor, Caffeine, which suggested that ATM/ATR signaling was activated by 7-d treatment. Furthermore, the increased expression of E2F1, p73, and Apaf-1 and p73 dissociation from HDM2 was induced by 7-d treatment, however, knockout of E2F1 expression reversed p73, Apaf-1, and p21(Cip1/WAF1) expression, reactivated cell cycle progression, and inhibited 7-d-induced apoptosis. Altogether our results for the first time indicate that 7-d mediates its growth inhibitory effects on CML p53-deficient cells via the activation of an E2F1-dependent mitochondrial and cell cycle checkpoint signaling pathway which subsequently targets p73, Apaf-1, and p21(Cip1/WAF1).

• Authors: Yiquan Li, Jin Shao, Ke Shen, Yufang Xu, Jianwen Liu, Xuhong Qian
• Journal: Journal of cellular biochemistry (J Cell Biochem) Vol. 113 Issue 10 Pg. 3165-77 (Oct 2012) ISSN: 1097-4644 [Electronic] United States
• PMID: 22593008 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Wiley Periodicals, Inc.

Chemical References

• 2-(3-(2-(dimethylamino)ethylamino)propyl)-6-(dodecylamino)-1H-benzo(de)isoquinoline-1,3(2H)-dione
• APAF1 protein, human
• Antineoplastic Agents
• Apoptotic Protease-Activating Factor 1
• CDKN1A protein, human
• Cell Cycle Proteins
• Cyclin-Dependent Kinase Inhibitor p21
• E2F1 Transcription Factor
• E2F1 protein, human
• Naphthalimides
• Organophosphonates
• Tumor Suppressor Protein p53
• amonafide
• Caffeine
• ATR protein, human
• Ataxia Telangiectasia Mutated Proteins
• Protein Serine-Threonine Kinases
• Adenine

Topics

• Adenine
• Animals
• Antineoplastic Agents (pharmacology)
• Apoptosis
• Apoptotic Protease-Activating Factor 1 (genetics, metabolism)
• Ataxia Telangiectasia Mutated Proteins
• Blotting, Western
• Caffeine (pharmacology)
• Cell Cycle Proteins (antagonists & inhibitors, genetics, metabolism)
• Comet Assay
• Cyclin-Dependent Kinase Inhibitor p21 (genetics, metabolism)
• DNA Breaks, Double-Stranded
• Dose-Response Relationship, Drug
• E2F1 Transcription Factor (genetics, metabolism)
• Flow Cytometry
• G2 Phase Cell Cycle Checkpoints
• Gene Knockout Techniques (methods)
• HCT116 Cells
• HeLa Cells
• Hep G2 Cells
• Humans
• Inhibitory Concentration 50
• K562 Cells
• M Phase Cell Cycle Checkpoints
• MCF-7 Cells
• Naphthalimides (pharmacology)
• Organophosphonates
• Protein Serine-Threonine Kinases (antagonists & inhibitors, genetics, metabolism)
• Rats
• Signal Transduction
• Time Factors
• Tumor Suppressor Protein p53 (genetics, metabolism)