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Updated: May 20, 2026
Using RNA-sequencing to Detect Novel Splice Variants Related to Drug Resistance in In Vitro Cancer Models
Published on: December 9, 2016
Differential gene expression in tamoxifen-resistant breast cancer cells revealed by a new analytical model of RNA-Seq
Kathryn J Huber-Keener1, Xiuping Liu, Zhong Wang
1Department of Pharmacology, The Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, United States of America.
Abstract:
Resistance to tamoxifen (Tam), a widely used antagonist of the estrogen receptor (ER), is a common obstacle to successful breast cancer treatment. While adjuvant therapy with Tam has been shown to significantly decrease the rate of disease recurrence and mortality, recurrent disease occurs in one third of patients treated with Tam within 5 years of therapy. A better understanding of gene expression alterations associated with Tam resistance will facilitate circumventing this problem. Using a next generation sequencing approach and a new bioinformatics model, we compared the transcriptomes of Tam-sensitive and Tam-resistant breast cancer cells for identification of genes involved in the development of Tam resistance. We identified differential expression of 1215 mRNA and 513 small RNA transcripts clustered into ERα functions, cell cycle regulation, transcription/translation, and mitochondrial dysfunction. The extent of alterations found at multiple levels of gene regulation highlights the ability of the Tam-resistant cells to modulate global gene expression. Alterations of small nucleolar RNA, oxidative phosphorylation, and proliferation processes in Tam-resistant cells present areas for diagnostic and therapeutic tool development for combating resistance to this anti-estrogen agent.
Insights
Tamoxifen resistance in breast cancer is a major challenge. This study identified key gene expression changes in tamoxifen-resistant cells, offering new targets for therapy.
Area of Science:
- Genomics and Molecular Biology
- Cancer Research
- Pharmacology
Background:
- Tamoxifen (Tam) is a crucial estrogen receptor (ER) antagonist for breast cancer treatment.
- Tamoxifen resistance develops in approximately one-third of patients within five years, leading to disease recurrence.
- Understanding gene expression changes in tamoxifen-resistant cells is vital for overcoming treatment failure.
Purpose of the Study:
- To identify genes and molecular pathways involved in tamoxifen resistance development.
- To compare transcriptomes of tamoxifen-sensitive and tamoxifen-resistant breast cancer cells.
- To explore potential diagnostic and therapeutic targets for combating tamoxifen resistance.
Main Methods:
- Employed next-generation sequencing to analyze global gene expression.
- Utilized a novel bioinformatics model for transcriptomic data analysis.
- Compared gene expression profiles between tamoxifen-sensitive and tamoxifen-resistant breast cancer cell lines.
Main Results:
- Identified differential expression of 1215 mRNA and 513 small RNA transcripts.
- Associated gene expression alterations with estrogen receptor alpha (ERα) functions, cell cycle regulation, transcription/translation, and mitochondrial dysfunction.
- Observed significant global gene expression modulation in tamoxifen-resistant cells, including alterations in small nucleolar RNA, oxidative phosphorylation, and proliferation.
Conclusions:
- Tamoxifen resistance involves complex, multi-level gene expression alterations.
- Specific pathways like mitochondrial dysfunction and altered proliferation are implicated in resistance.
- Identified molecular changes provide potential targets for developing new diagnostic and therapeutic strategies against tamoxifen resistance.
