Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer.
Maternal embryonic leucine-zipper kinase (MELK) regulates cell cycle progression and is highly expressed in many cancers. The molecular mechanism of MELK dysregulation has not been determined in aggressive forms of breast cancer, such as triple negative breast cancer (TNBC). To evaluate molecular ma...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2022-01-01
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| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0268693 |
| _version_ | 1811295124611661824 |
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| author | Ashley A Hardeman Yoo Jane Han Tatyana A Grushko Jeffrey Mueller Maria J Gomez Yonglan Zheng Olufunmilayo I Olopade |
| author_facet | Ashley A Hardeman Yoo Jane Han Tatyana A Grushko Jeffrey Mueller Maria J Gomez Yonglan Zheng Olufunmilayo I Olopade |
| author_sort | Ashley A Hardeman |
| collection | DOAJ |
| description | Maternal embryonic leucine-zipper kinase (MELK) regulates cell cycle progression and is highly expressed in many cancers. The molecular mechanism of MELK dysregulation has not been determined in aggressive forms of breast cancer, such as triple negative breast cancer (TNBC). To evaluate molecular markers of MELK aberrations in aggressive breast cancer, we assessed MELK gene amplification and expression in breast tumors. MELK mRNA expression is highly up-regulated in basal-like breast cancer (BLBC), the major molecular subtype of TNBC, compared to luminal or other subtypes of breast tumors. MELK copy number (CN) gains are significantly associated with BLBC, whereas no significant association of CpG site methylation or histone modifications with breast cancer subtypes was observed. Accordingly, the CN gains appear to contribute to an increase in MELK expression, with a significant correlation between mRNA expression and CN in breast tumors and cell lines. Furthermore, immunohistochemistry (IHC) assays revealed that both nuclear and cytoplasmic staining scores of MELK were significantly higher in invasive ductal carcinoma (IDC) tumors compared to ductal carcinoma in situ (DCIS) and normal breast tissues. Our data showed that upregulation of MELK in BLBC may be in part driven by CN gains, rather than epigenetic modifications, indicating a potential for overexpression and CN gains of MELK to be developed as a diagnostic and prognostic marker to identify patients who have more aggressive breast cancer. |
| first_indexed | 2024-04-13T05:27:53Z |
| format | Article |
| id | doaj.art-b7d9e314a3ee46559e693fba6ad190a7 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-13T05:27:53Z |
| publishDate | 2022-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-b7d9e314a3ee46559e693fba6ad190a72022-12-22T03:00:32ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-01176e026869310.1371/journal.pone.0268693Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer.Ashley A HardemanYoo Jane HanTatyana A GrushkoJeffrey MuellerMaria J GomezYonglan ZhengOlufunmilayo I OlopadeMaternal embryonic leucine-zipper kinase (MELK) regulates cell cycle progression and is highly expressed in many cancers. The molecular mechanism of MELK dysregulation has not been determined in aggressive forms of breast cancer, such as triple negative breast cancer (TNBC). To evaluate molecular markers of MELK aberrations in aggressive breast cancer, we assessed MELK gene amplification and expression in breast tumors. MELK mRNA expression is highly up-regulated in basal-like breast cancer (BLBC), the major molecular subtype of TNBC, compared to luminal or other subtypes of breast tumors. MELK copy number (CN) gains are significantly associated with BLBC, whereas no significant association of CpG site methylation or histone modifications with breast cancer subtypes was observed. Accordingly, the CN gains appear to contribute to an increase in MELK expression, with a significant correlation between mRNA expression and CN in breast tumors and cell lines. Furthermore, immunohistochemistry (IHC) assays revealed that both nuclear and cytoplasmic staining scores of MELK were significantly higher in invasive ductal carcinoma (IDC) tumors compared to ductal carcinoma in situ (DCIS) and normal breast tissues. Our data showed that upregulation of MELK in BLBC may be in part driven by CN gains, rather than epigenetic modifications, indicating a potential for overexpression and CN gains of MELK to be developed as a diagnostic and prognostic marker to identify patients who have more aggressive breast cancer.https://doi.org/10.1371/journal.pone.0268693 |
| spellingShingle | Ashley A Hardeman Yoo Jane Han Tatyana A Grushko Jeffrey Mueller Maria J Gomez Yonglan Zheng Olufunmilayo I Olopade Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer. PLoS ONE |
| title | Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer. |
| title_full | Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer. |
| title_fullStr | Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer. |
| title_full_unstemmed | Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer. |
| title_short | Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer. |
| title_sort | subtype specific expression of melk is partly due to copy number alterations in breast cancer |
| url | https://doi.org/10.1371/journal.pone.0268693 |
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