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Updated: Jun 6, 2025
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Assessment of Selective mRNA Translation in Mammalian Cells by Polysome Profiling
Published on: October 28, 2014
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p21Waf1/Cip1 Is a Novel Downstream Target of 40S Ribosomal S6 Kinase 2.
Alakananda Basu1, Zhenyu Xuan2
1Department of Microbiology, Immunology and Genetics, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
Cancers
|November 27, 2024
Summary
Ribosomal S6 kinase 2 (S6K2) promotes breast cancer cell survival by downregulating p21 and Mcl-1. Silencing S6K2 sensitizes cells to doxorubicin, offering potential therapeutic strategies.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Signaling
Background:
- Ribosomal S6 kinase 2 (S6K2) is a homolog of S6K1, downstream of mTORC1.
- The downstream effectors and functions of S6K2 in breast cancer are not well understood.
Purpose of the Study:
- To investigate the role of S6K2 in breast cancer cell survival.
- To identify novel downstream targets of S6K2 using transcriptome profiling.
Main Methods:
- RNA-sequencing (RNA-Seq) for target identification.
- siRNA and plasmid transfections for gene manipulation.
- Western blot for protein analysis.
- Doxorubicin treatment to assess apoptosis.
Main Results:
- S6K2 silencing, not S6K1, decreased p21 levels in breast cancer cells.
- Akt1 and Akt2 influenced p21 levels differently across cell lines.
- S6K2 knockdown increased JUN mRNA, and cJun knockdown enhanced p21.
- S6K2 or p21 silencing sensitized cells to doxorubicin via JNK-mediated Mcl-1 downregulation.
Conclusions:
- S6K2 knockdown enhances doxorubicin-induced apoptosis.
- This effect is mediated by the downregulation of p21 and Mcl-1.
- The Akt and JNK signaling pathways are involved in S6K2's regulation of apoptosis.
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