SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88
Abstract Background Resistance to trastuzumab has become a leading cause of mortality in breast cancer patients and is one of the major obstacles for improving the clinical outcome. Cell behavior can be modulated by long non-coding RNAs (lncRNAs), but the contribution of lncRNAs in trastuzumab resis...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2018-08-01
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| Series: | Journal of Experimental & Clinical Cancer Research |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13046-018-0875-3 |
| _version_ | 1811288242046107648 |
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| author | Huaying Dong Wei Wang Shaowei Mo Ru Chen Kejian Zou Jing Han Fan Zhang Jianguo Hu |
| author_facet | Huaying Dong Wei Wang Shaowei Mo Ru Chen Kejian Zou Jing Han Fan Zhang Jianguo Hu |
| author_sort | Huaying Dong |
| collection | DOAJ |
| description | Abstract Background Resistance to trastuzumab has become a leading cause of mortality in breast cancer patients and is one of the major obstacles for improving the clinical outcome. Cell behavior can be modulated by long non-coding RNAs (lncRNAs), but the contribution of lncRNAs in trastuzumab resistance to breast cancer is largely unknown. To this end, the involvement and regulatory function of lncRNA AGAP2-AS1 in human breast cancer are yet to be investigated. Methods Trastuzumab-resistant SKBR-3 and BT474 cells were obtained by continuous culture with 5 mg/mL trastuzumab for 6 months. RT-qPCR assay was used to determine the expression of AGAP2-AS1 in tissues and cells. RNA fluorescence in situ hybridization was used to investigate the subcellular location of AGAP2-AS1 in breast cancer cells. Bioinformatic analysis, chromatin immunoprecipitation (ChIP), RNA immunoprecipitation (RIP), western blotting, and immunofluorescence were carried out to verify the regulatory interaction of AGAP2-AS1, CREB-binding protein (CBP), and MyD88. In addition, a series of in vitro assays and a xenograft tumor model were used to analyze the functions of AGAP2-AS1 in breast cancer cells. Results AGAP2-AS1 was upregulated and transcriptionally induced by SP1 in breast cancer. Overexpression of AGAP2-AS1 promoted cell growth, suppressed apoptosis, and caused trastuzumab resistance, whereas knockdown of AGAP2-AS1 showed an opposite effect. MyD88 was identified as a downstream target of AGAP2-AS1 and mediated the AGAP2-AS1-induced oncogenic effects. Mechanistically, the RIP assay revealed that AGAP2-AS1 could bind to CBP, a transcriptional co-activator. ChIP assays showed that AGAP2-AS1-bound CBP increased the enrichment of H3K27ac at the promoter region of MyD88, thus resulting in the upregulation of MyD88. Gain- and loss-of-function assays confirmed that the NF-κB pathway was activated by MyD88 and AGAP2-AS1. Furthermore, high AGAP2-AS1 expression was associated with poor clinical response to trastuzumab therapy in breast cancer patients. Conclusion AGAP2-AS1 could promote breast cancer growth and trastuzumab resistance by activating the NF-κB signaling pathway and upregulating MyD88 expression. Therefore, AGAP2-AS1 may serve as a novel biomarker for prognosis and act as a therapeutic target for the trastuzumab treatment. |
| first_indexed | 2024-04-13T03:33:37Z |
| format | Article |
| id | doaj.art-402f9fd068fd4401932ebb1c34864b98 |
| institution | Directory Open Access Journal |
| issn | 1756-9966 |
| language | English |
| last_indexed | 2024-04-13T03:33:37Z |
| publishDate | 2018-08-01 |
| publisher | BMC |
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| series | Journal of Experimental & Clinical Cancer Research |
| spelling | doaj.art-402f9fd068fd4401932ebb1c34864b982022-12-22T03:04:23ZengBMCJournal of Experimental & Clinical Cancer Research1756-99662018-08-0137111510.1186/s13046-018-0875-3SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88Huaying Dong0Wei Wang1Shaowei Mo2Ru Chen3Kejian Zou4Jing Han5Fan Zhang6Jianguo Hu7Department of General Surgery, Hainan General Hospital, Jinan UniversityDepartment of General Surgery, Hainan General Hospital, Jinan UniversityDepartment of Science and Education, Hainan Maternal and Child health hospitalDepartment of General Surgery, Hainan General Hospital, Jinan UniversityDepartment of General Surgery, Hainan General Hospital, Jinan UniversityDepartment of General Surgery, Hainan General Hospital, Jinan UniversityDepartment of General Surgery, Hainan General Hospital, Jinan UniversityDepartment of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical UniversityAbstract Background Resistance to trastuzumab has become a leading cause of mortality in breast cancer patients and is one of the major obstacles for improving the clinical outcome. Cell behavior can be modulated by long non-coding RNAs (lncRNAs), but the contribution of lncRNAs in trastuzumab resistance to breast cancer is largely unknown. To this end, the involvement and regulatory function of lncRNA AGAP2-AS1 in human breast cancer are yet to be investigated. Methods Trastuzumab-resistant SKBR-3 and BT474 cells were obtained by continuous culture with 5 mg/mL trastuzumab for 6 months. RT-qPCR assay was used to determine the expression of AGAP2-AS1 in tissues and cells. RNA fluorescence in situ hybridization was used to investigate the subcellular location of AGAP2-AS1 in breast cancer cells. Bioinformatic analysis, chromatin immunoprecipitation (ChIP), RNA immunoprecipitation (RIP), western blotting, and immunofluorescence were carried out to verify the regulatory interaction of AGAP2-AS1, CREB-binding protein (CBP), and MyD88. In addition, a series of in vitro assays and a xenograft tumor model were used to analyze the functions of AGAP2-AS1 in breast cancer cells. Results AGAP2-AS1 was upregulated and transcriptionally induced by SP1 in breast cancer. Overexpression of AGAP2-AS1 promoted cell growth, suppressed apoptosis, and caused trastuzumab resistance, whereas knockdown of AGAP2-AS1 showed an opposite effect. MyD88 was identified as a downstream target of AGAP2-AS1 and mediated the AGAP2-AS1-induced oncogenic effects. Mechanistically, the RIP assay revealed that AGAP2-AS1 could bind to CBP, a transcriptional co-activator. ChIP assays showed that AGAP2-AS1-bound CBP increased the enrichment of H3K27ac at the promoter region of MyD88, thus resulting in the upregulation of MyD88. Gain- and loss-of-function assays confirmed that the NF-κB pathway was activated by MyD88 and AGAP2-AS1. Furthermore, high AGAP2-AS1 expression was associated with poor clinical response to trastuzumab therapy in breast cancer patients. Conclusion AGAP2-AS1 could promote breast cancer growth and trastuzumab resistance by activating the NF-κB signaling pathway and upregulating MyD88 expression. Therefore, AGAP2-AS1 may serve as a novel biomarker for prognosis and act as a therapeutic target for the trastuzumab treatment.http://link.springer.com/article/10.1186/s13046-018-0875-3SP1Breast cancerlncRNA AGAP2-AS1MyD88H3K27 acetylationTrastuzumab |
| spellingShingle | Huaying Dong Wei Wang Shaowei Mo Ru Chen Kejian Zou Jing Han Fan Zhang Jianguo Hu SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88 Journal of Experimental & Clinical Cancer Research SP1 Breast cancer lncRNA AGAP2-AS1 MyD88 H3K27 acetylation Trastuzumab |
| title | SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88 |
| title_full | SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88 |
| title_fullStr | SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88 |
| title_full_unstemmed | SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88 |
| title_short | SP1-induced lncRNA AGAP2-AS1 expression promotes chemoresistance of breast cancer by epigenetic regulation of MyD88 |
| title_sort | sp1 induced lncrna agap2 as1 expression promotes chemoresistance of breast cancer by epigenetic regulation of myd88 |
| topic | SP1 Breast cancer lncRNA AGAP2-AS1 MyD88 H3K27 acetylation Trastuzumab |
| url | http://link.springer.com/article/10.1186/s13046-018-0875-3 |
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