Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival.
Calcium uptake through the mitochondrial Ca2+ uniporter (MCU) is thought to be essential in regulating cellular signaling events, energy status, and survival. Functional dissection of the uniporter is now possible through the recent identification of the genes encoding for MCU protein complex subuni...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2014-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4011874?pdf=render |
| _version_ | 1819115495213760512 |
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| author | Duane D Hall Yuejin Wu Frederick E Domann Douglas R Spitz Mark E Anderson |
| author_facet | Duane D Hall Yuejin Wu Frederick E Domann Douglas R Spitz Mark E Anderson |
| author_sort | Duane D Hall |
| collection | DOAJ |
| description | Calcium uptake through the mitochondrial Ca2+ uniporter (MCU) is thought to be essential in regulating cellular signaling events, energy status, and survival. Functional dissection of the uniporter is now possible through the recent identification of the genes encoding for MCU protein complex subunits. Cancer cells exhibit many aspects of mitochondrial dysfunction associated with altered mitochondrial Ca2+ levels including resistance to apoptosis, increased reactive oxygen species production and decreased oxidative metabolism. We used a publically available database to determine that breast cancer patient outcomes negatively correlated with increased MCU Ca2+ conducting pore subunit expression and decreased MICU1 regulatory subunit expression. We hypothesized breast cancer cells may therefore be sensitive to MCU channel manipulation. We used the widely studied MDA-MB-231 breast cancer cell line to investigate whether disruption or increased activation of mitochondrial Ca2+ uptake with specific siRNAs and adenoviral overexpression constructs would sensitize these cells to therapy-related stress. MDA-MB-231 cells were found to contain functional MCU channels that readily respond to cellular stimulation and elicit robust AMPK phosphorylation responses to nutrient withdrawal. Surprisingly, knockdown of MCU or MICU1 did not affect reactive oxygen species production or cause significant effects on clonogenic cell survival of MDA-MB-231 cells exposed to irradiation, chemotherapeutic agents, or nutrient deprivation. Overexpression of wild type or a dominant negative mutant MCU did not affect basal cloning efficiency or ceramide-induced cell killing. In contrast, non-cancerous breast epithelial HMEC cells showed reduced survival after MCU or MICU1 knockdown. These results support the conclusion that MDA-MB-231 breast cancer cells do not rely on MCU or MICU1 activity for survival in contrast to previous findings in cells derived from cervical, colon, and prostate cancers and suggest that not all carcinomas will be sensitive to therapies targeting mitochondrial Ca2+ uptake mechanisms. |
| first_indexed | 2024-12-22T05:02:06Z |
| format | Article |
| id | doaj.art-5beadb15c71d4faebe8aa30b2458f4a0 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-22T05:02:06Z |
| publishDate | 2014-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-5beadb15c71d4faebe8aa30b2458f4a02022-12-21T18:38:13ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0195e9686610.1371/journal.pone.0096866Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival.Duane D HallYuejin WuFrederick E DomannDouglas R SpitzMark E AndersonCalcium uptake through the mitochondrial Ca2+ uniporter (MCU) is thought to be essential in regulating cellular signaling events, energy status, and survival. Functional dissection of the uniporter is now possible through the recent identification of the genes encoding for MCU protein complex subunits. Cancer cells exhibit many aspects of mitochondrial dysfunction associated with altered mitochondrial Ca2+ levels including resistance to apoptosis, increased reactive oxygen species production and decreased oxidative metabolism. We used a publically available database to determine that breast cancer patient outcomes negatively correlated with increased MCU Ca2+ conducting pore subunit expression and decreased MICU1 regulatory subunit expression. We hypothesized breast cancer cells may therefore be sensitive to MCU channel manipulation. We used the widely studied MDA-MB-231 breast cancer cell line to investigate whether disruption or increased activation of mitochondrial Ca2+ uptake with specific siRNAs and adenoviral overexpression constructs would sensitize these cells to therapy-related stress. MDA-MB-231 cells were found to contain functional MCU channels that readily respond to cellular stimulation and elicit robust AMPK phosphorylation responses to nutrient withdrawal. Surprisingly, knockdown of MCU or MICU1 did not affect reactive oxygen species production or cause significant effects on clonogenic cell survival of MDA-MB-231 cells exposed to irradiation, chemotherapeutic agents, or nutrient deprivation. Overexpression of wild type or a dominant negative mutant MCU did not affect basal cloning efficiency or ceramide-induced cell killing. In contrast, non-cancerous breast epithelial HMEC cells showed reduced survival after MCU or MICU1 knockdown. These results support the conclusion that MDA-MB-231 breast cancer cells do not rely on MCU or MICU1 activity for survival in contrast to previous findings in cells derived from cervical, colon, and prostate cancers and suggest that not all carcinomas will be sensitive to therapies targeting mitochondrial Ca2+ uptake mechanisms.http://europepmc.org/articles/PMC4011874?pdf=render |
| spellingShingle | Duane D Hall Yuejin Wu Frederick E Domann Douglas R Spitz Mark E Anderson Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival. PLoS ONE |
| title | Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival. |
| title_full | Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival. |
| title_fullStr | Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival. |
| title_full_unstemmed | Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival. |
| title_short | Mitochondrial calcium uniporter activity is dispensable for MDA-MB-231 breast carcinoma cell survival. |
| title_sort | mitochondrial calcium uniporter activity is dispensable for mda mb 231 breast carcinoma cell survival |
| url | http://europepmc.org/articles/PMC4011874?pdf=render |
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