Deregulation of cofactor of BRCA1 expression in breast cancer cells

Jianlong Sun, Gareth Watkins, Ashley L. Blair, Christopher Moskaluk, Sagar Ghosh, Wen G. Jiang, Rong Li

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Cofactor of BRCA1 (COBRA1) is an integral component of the human negative elongation factor (NELF), a four-subunit protein complex that inhibits transcription elongation. Previous in vivo work indicates that COBRA1 and the rest of the NELF complex repress estrogen-dependent transcription and the growth of breast cancer cells. In light of the COBRA1 function in breast cancer-related gene expression, we sought to examine regulation of COBRA1 expression in both established breast cancer cell lines and breast carcinoma tissues. We found that COBRA1 expression was inversely correlated with breast cancer progression, as tumor samples of patients who had distant metastasis and local recurrence expressed very low levels of COBRA1 mRNA when compared to those who were disease free for over 10 years (P = 0.0065 and 0.0081, respectively). Using both breast and prostate cancer cell lines, we also explored the possible mechanisms by which COBRA1 expression is regulated. Our results indicate that the protein abundance of COBRA1 and the other NELF subunits are mutually influenced in a tightly coordinated fashion. Small interfering RNA (siRNA) that targeted at one NELF subunit dampened the protein levels of all four subunits. Conversely, ectopic expression of COBRA1 in the knockdown cells partially rescues the co-depletion of the NELF subunits. In addition, our study suggests that a post-transcriptional, proteasome-independent mechanism is involved in the interdependent regulation of the NELF abundance. Furthermore, a lack of COBRA1 expression in breast carcinoma may serve as a useful indicator for poor prognosis.

Original languageEnglish (US)
Pages (from-to)1798-1807
Number of pages10
JournalJournal of Cellular Biochemistry
Volume103
Issue number6
DOIs
StatePublished - Apr 15 2008

Fingerprint

Deregulation
Cells
Breast Neoplasms
Transcription
Protein Subunits
Cell Line
Proteasome Endopeptidase Complex
Neoplasm Genes
Gene expression
Small Interfering RNA
negative elongation factor
Tumors
Elongation
Estrogens
Proteins
Prostatic Neoplasms
Tissue
Messenger RNA
Neoplasm Metastasis
Gene Expression

Keywords

  • COBRA1
  • Metastatic breast cancer
  • NELF
  • Protein stability
  • Transcriptional repression

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology

Cite this

Sun, J., Watkins, G., Blair, A. L., Moskaluk, C., Ghosh, S., Jiang, W. G., & Li, R. (2008). Deregulation of cofactor of BRCA1 expression in breast cancer cells. Journal of Cellular Biochemistry, 103(6), 1798-1807. https://doi.org/10.1002/jcb.21568

Deregulation of cofactor of BRCA1 expression in breast cancer cells. / Sun, Jianlong; Watkins, Gareth; Blair, Ashley L.; Moskaluk, Christopher; Ghosh, Sagar; Jiang, Wen G.; Li, Rong.

In: Journal of Cellular Biochemistry, Vol. 103, No. 6, 15.04.2008, p. 1798-1807.

Research output: Contribution to journalArticle

Sun, J, Watkins, G, Blair, AL, Moskaluk, C, Ghosh, S, Jiang, WG & Li, R 2008, 'Deregulation of cofactor of BRCA1 expression in breast cancer cells', Journal of Cellular Biochemistry, vol. 103, no. 6, pp. 1798-1807. https://doi.org/10.1002/jcb.21568
Sun J, Watkins G, Blair AL, Moskaluk C, Ghosh S, Jiang WG et al. Deregulation of cofactor of BRCA1 expression in breast cancer cells. Journal of Cellular Biochemistry. 2008 Apr 15;103(6):1798-1807. https://doi.org/10.1002/jcb.21568
Sun, Jianlong ; Watkins, Gareth ; Blair, Ashley L. ; Moskaluk, Christopher ; Ghosh, Sagar ; Jiang, Wen G. ; Li, Rong. / Deregulation of cofactor of BRCA1 expression in breast cancer cells. In: Journal of Cellular Biochemistry. 2008 ; Vol. 103, No. 6. pp. 1798-1807.
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