Hypomethylation and apoptosis in 5-azacytidine-treated myeloid cells
(2008) In Experimental Hematology 36(2). p.149-157- Abstract
- OBJECTIVE: Although clinically approved for myelodysplastic syndromes (MDS), the mode of action of 5-azacytidine has not been well understood at the cellular level. The present study aimed at characterizing the mechanisms for 5-azacytidine-induced apoptosis, as well as the presence of a possible link between apoptosis and DNA hypomethylation. MATERIALS AND METHODS: We investigated the effects of 5-azacytidine on a spectrum of specific apoptotic pathways, as well as on global DNA methylation, assessed by luminometric methylation assay, in myeloid (P39, HL60) and T cells (Jurkat). RESULTS: 5-Azacytidine induced dose-dependent apoptosis as well as non-dose-dependent global DNA hypomethylation at concentrations >/=0.5 muM. Hypomethylation... (More)
- OBJECTIVE: Although clinically approved for myelodysplastic syndromes (MDS), the mode of action of 5-azacytidine has not been well understood at the cellular level. The present study aimed at characterizing the mechanisms for 5-azacytidine-induced apoptosis, as well as the presence of a possible link between apoptosis and DNA hypomethylation. MATERIALS AND METHODS: We investigated the effects of 5-azacytidine on a spectrum of specific apoptotic pathways, as well as on global DNA methylation, assessed by luminometric methylation assay, in myeloid (P39, HL60) and T cells (Jurkat). RESULTS: 5-Azacytidine induced dose-dependent apoptosis as well as non-dose-dependent global DNA hypomethylation at concentrations >/=0.5 muM. Hypomethylation was observed in the sorted apoptotic fraction (41% decrease with 1 muM after 24 hours), while nonapoptotic cells retained a methylation pattern similar to untreated cells (+/-6%). The induced apoptotic pattern involved several pathways: cleavage of Bcl-2 family proteins, activation of caspase-2 and -3-like, mitochondrial involvement characterized by loss of transmembrane potential (tetramethylrhodamine ethyl ester [TMRE]) and cytochrome release, and acidification of cytosol. Selective inhibition of caspase-3-like, -2, -8, -9, and pan-caspase activity, as well as stabilization of cytosolic pH by monensin completely failed to block apoptosis. Poly(ADP-ribose) polymerase (PARP) inhibitors only partially inhibited loss of TMRE (32% reduction) and caspase-2 activity (38% reduction); indicative of PARP operation (or action) upstream of caspase-2. Moreover, cytosine arabinoside induced a similar degree of apoptosis, while leaving methylation status mainly unaffected. CONCLUSIONS: 5-Azacytidine acts via multiple and separately regulated pathways, including parallel induction of hypomethylation. The broad action of 5-azacytidine may explain its therapeutic effects in poor-prognostic MDS. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1299082
- author
- Khan, Rasheed LU ; Schmidt-Mende, M ; Karimi, M ; Gogvadze, V ; Hassan, M ; Ekstrom, T J ; Zhivotovsky, T and Hellstrom-Lindberg, E
- publishing date
- 2008
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Experimental Hematology
- volume
- 36
- issue
- 2
- pages
- 149 - 157
- publisher
- Elsevier
- external identifiers
-
- scopus:38149088287
- ISSN
- 1873-2399
- DOI
- 10.1016/j.exphem.2007.10.002
- language
- English
- LU publication?
- no
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Experimental Clinical Chemistry (013016010)
- id
- 58e56b2c-d000-4c68-9732-ee93940cba7a (old id 1299082)
- date added to LUP
- 2016-04-01 12:01:14
- date last changed
- 2024-01-08 05:05:41
@article{58e56b2c-d000-4c68-9732-ee93940cba7a,
abstract = {{OBJECTIVE: Although clinically approved for myelodysplastic syndromes (MDS), the mode of action of 5-azacytidine has not been well understood at the cellular level. The present study aimed at characterizing the mechanisms for 5-azacytidine-induced apoptosis, as well as the presence of a possible link between apoptosis and DNA hypomethylation. MATERIALS AND METHODS: We investigated the effects of 5-azacytidine on a spectrum of specific apoptotic pathways, as well as on global DNA methylation, assessed by luminometric methylation assay, in myeloid (P39, HL60) and T cells (Jurkat). RESULTS: 5-Azacytidine induced dose-dependent apoptosis as well as non-dose-dependent global DNA hypomethylation at concentrations >/=0.5 muM. Hypomethylation was observed in the sorted apoptotic fraction (41% decrease with 1 muM after 24 hours), while nonapoptotic cells retained a methylation pattern similar to untreated cells (+/-6%). The induced apoptotic pattern involved several pathways: cleavage of Bcl-2 family proteins, activation of caspase-2 and -3-like, mitochondrial involvement characterized by loss of transmembrane potential (tetramethylrhodamine ethyl ester [TMRE]) and cytochrome release, and acidification of cytosol. Selective inhibition of caspase-3-like, -2, -8, -9, and pan-caspase activity, as well as stabilization of cytosolic pH by monensin completely failed to block apoptosis. Poly(ADP-ribose) polymerase (PARP) inhibitors only partially inhibited loss of TMRE (32% reduction) and caspase-2 activity (38% reduction); indicative of PARP operation (or action) upstream of caspase-2. Moreover, cytosine arabinoside induced a similar degree of apoptosis, while leaving methylation status mainly unaffected. CONCLUSIONS: 5-Azacytidine acts via multiple and separately regulated pathways, including parallel induction of hypomethylation. The broad action of 5-azacytidine may explain its therapeutic effects in poor-prognostic MDS.}},
author = {{Khan, Rasheed and Schmidt-Mende, M and Karimi, M and Gogvadze, V and Hassan, M and Ekstrom, T J and Zhivotovsky, T and Hellstrom-Lindberg, E}},
issn = {{1873-2399}},
language = {{eng}},
number = {{2}},
pages = {{149--157}},
publisher = {{Elsevier}},
series = {{Experimental Hematology}},
title = {{Hypomethylation and apoptosis in 5-azacytidine-treated myeloid cells}},
url = {{http://dx.doi.org/10.1016/j.exphem.2007.10.002}},
doi = {{10.1016/j.exphem.2007.10.002}},
volume = {{36}},
year = {{2008}},
}