 | |  | |  | |  | |  | |  | |  | |  |
| IJCEM Copyright © 2008-All rights reserved. Published by e-Century Publishing Corporation, Madison, WI 53711 |
Int J Clin Exp Med 2010;3(2):95-102
Original Article
Azacytidine induces cell cycle arrest and suppression of neuroendocrine markers in
carcinoids
Vinita M. Alexander, Madhuchhanda Roy, Kristen A. Steffens, Muthusamy Kunnimalaiyaan, Herbert Chen
Endocrine Surgery Research Laboratory, Department of Surgery, University of Wisconsin, Madison, Wisconsin, USA
Received March 2, 2010, accepted March 23, 2010, available online March 27, 2010
Abstract: Neuroendocrine tumors (NETs) hypersecrete neuropeptides that cause debilitating symptoms of carcinoid syndrome,
including cardiac abnormalities. Surgical resection is the only potentially curative treatment for NETs; however, 90% of NE cancer
patients are not candidates for surgery due to extensive hepatic sites involved with NETs. Recently, DNA methyltransferase inhibitors
(DNMTI) such as azacytidine (AzaC) have shown efficacy in clinical treatments of hematological malignancies, but effects on NETs are
not well-studied. We hypothesized that this novel class of drugs inhibits NET cell growth and decreases NE markers. Three carcinoid
types—human midgut (CDNT2.5), pulmonary (H727), and gastrointestinal (BON)— were treated with AzaC (0-100uM) over 6 days. MTT
Assays were used to measure cellular proliferation. Western blots were performed with antibodies against chromogranin A (CgA),
Neuron-Specific Enolase (NSE), and Cyclin B1. Flow cytometric data was collected from AzaC-treated CNDT2.5 cells for DNA cell cycle
analysis. Results showed that treatment of CDNT2.5, H727, and BON carcinoid cells with AzaC resulted in a dose-dependent reduction
in tumor cell proliferation. Flow cytometric analysis showed that AzaC-treated cells accumulate in the G2 Phase of cell cycle. AzaC
treatment led to: significant decreases in CgA and NSE, indicating that AzaC inhibits neuroendocrine markers; and significant
increases in the levels of Cyclin B1, further supporting the flow cytometric data and conclusion that AzaC induces G2/M arrest. The data
indicate that AzaC suppresses cell growth in three different carcinoid types, reduces neuroendocrine markers, and inhibits cell
proliferation by inducing G2/M phase arrest. The results suggest that DNMTIs may be a novel class of therapeutic agents that can
effectively control tumor growth and the release of bioactive peptides in patients with NETs. (IJCEM1003004).
Key words: Azacytidine, euroendocrine Tumors, chromogranina A – neuron specific enolase – G2/M arrest
Full Text PDF
Address all correspondence to:
Herbert Chen MD, FACS
H4/722 Clinical Science Center,
600 Highland Avenue, Madison, Wisconsin
53792-7375;
Telephone: (608) 263-1387;
Fax: (608) 263-7652;
E-mail: chen@surgery.wisc.edu
Original Article
Azacytidine induces cell cycle arrest and suppression of neuroendocrine markers in
carcinoids
Vinita M. Alexander, Madhuchhanda Roy, Kristen A. Steffens, Muthusamy Kunnimalaiyaan, Herbert Chen
Endocrine Surgery Research Laboratory, Department of Surgery, University of Wisconsin, Madison, Wisconsin, USA
Received March 2, 2010, accepted March 23, 2010, available online March 27, 2010
Abstract: Neuroendocrine tumors (NETs) hypersecrete neuropeptides that cause debilitating symptoms of carcinoid syndrome,
including cardiac abnormalities. Surgical resection is the only potentially curative treatment for NETs; however, 90% of NE cancer
patients are not candidates for surgery due to extensive hepatic sites involved with NETs. Recently, DNA methyltransferase inhibitors
(DNMTI) such as azacytidine (AzaC) have shown efficacy in clinical treatments of hematological malignancies, but effects on NETs are
not well-studied. We hypothesized that this novel class of drugs inhibits NET cell growth and decreases NE markers. Three carcinoid
types—human midgut (CDNT2.5), pulmonary (H727), and gastrointestinal (BON)— were treated with AzaC (0-100uM) over 6 days. MTT
Assays were used to measure cellular proliferation. Western blots were performed with antibodies against chromogranin A (CgA),
Neuron-Specific Enolase (NSE), and Cyclin B1. Flow cytometric data was collected from AzaC-treated CNDT2.5 cells for DNA cell cycle
analysis. Results showed that treatment of CDNT2.5, H727, and BON carcinoid cells with AzaC resulted in a dose-dependent reduction
in tumor cell proliferation. Flow cytometric analysis showed that AzaC-treated cells accumulate in the G2 Phase of cell cycle. AzaC
treatment led to: significant decreases in CgA and NSE, indicating that AzaC inhibits neuroendocrine markers; and significant
increases in the levels of Cyclin B1, further supporting the flow cytometric data and conclusion that AzaC induces G2/M arrest. The data
indicate that AzaC suppresses cell growth in three different carcinoid types, reduces neuroendocrine markers, and inhibits cell
proliferation by inducing G2/M phase arrest. The results suggest that DNMTIs may be a novel class of therapeutic agents that can
effectively control tumor growth and the release of bioactive peptides in patients with NETs. (IJCEM1003004).
Key words: Azacytidine, euroendocrine Tumors, chromogranina A – neuron specific enolase – G2/M arrest
Full Text PDF
Address all correspondence to:
Herbert Chen MD, FACS
H4/722 Clinical Science Center,
600 Highland Avenue, Madison, Wisconsin
53792-7375;
Telephone: (608) 263-1387;
Fax: (608) 263-7652;
E-mail: chen@surgery.wisc.edu
