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Transcriptome analysis of luminal breast cancer reveals a role for LOL in tumor progression and tamoxifen resistance
Author(s) -
Sun Wei,
Xu Xiaoen,
Jiang Yizhou,
Jin Xi,
Zhou Ping,
Liu Yirong,
Guo Yajie,
Ma Ding,
Zuo Wenjia,
Huang Shenglin,
He Xianghuo,
Shao Zhiming
Publication year - 2019
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.32185
Subject(s) - tamoxifen , breast cancer , cancer research , estrogen , cancer , transcriptome , estrogen receptor , medicine , microrna , tumor progression , antiestrogen , biology , oncology , gene expression , gene , biochemistry
Luminal breast cancer (BC) has a sustained risk of late disease recurrence and death. Considerable numbers of patients suffer from antiendocrine therapy resistance. Here, we identified a novel lncRNA whose expression is high in breast cancer and especially higher in luminal breast cancer, dubbed LOL (lncRNA of luminal), that acts as a natural sponge for let‐7 microRNAs to regulate tumor growth and tamoxifen resistance. LOL overexpression in parental MCF‐7 cells exhibited a proliferative advantage in the addition of tamoxifen than negative control. Knocking down LOL in TamR MCF‐7 cells, recovered the sensitivity of cells to tamoxifen. Strikingly, we demonstrated that LOL is transcribed from a genomic locus of an enhancer to maintain its high expression in luminal BC and that it is extremely sensitive to enhancer‐regulating factors, such as ZMYND8 and BRD4. Estrogen deprivation or ERα signaling pathway blockage can further stimulate LOL expression, which can promote tumor progression. Clinical analysis of 374 luminal breast cancer samples indicated that LOL is an independent prognostic factor for poor survival in luminal BC. In conclusion, targeting LOL using preclinical/clinical drugs, such as BRD4 inhibitors, may represent a promising approach to inhibit luminal breast cancer progression and tamoxifen resistance.