Expression analysis of the MCPH1/BRIT1 and BRCA1 tumor suppressor genes and telomerase splice variants in epithelial ovarian cancer

Gene. 2018 Sep 25:672:34-44. doi: 10.1016/j.gene.2018.05.113. Epub 2018 May 31.

Abstract

Aims: The aim of this study was to explore the correlation of hTERT splice variant expression with MCPH1/BRIT1 and BRCA1 expression in epithelial ovarian cancer (EOC) samples.

Background: Telomerase activation can contribute to the progression of tumors and the development of cancer. However, the regulation of telomerase activity remains unclear. MCPH1 (also known as BRIT1, BRCT-repeat inhibitor of hTERT expression) and BRCA1 are tumor suppressor genes that have been linked to telomerase expression.

Methods: qPCR was used to investigate telomerase splice variants, MCPH1/BRIT1 and BRCA1 expression in EOC tissue and primary cultures.

Results: The wild type α+/β+ hTERT variant was the most common splice variant in the EOC samples, followed by α+/β- hTERT, a dominant negative regulator of telomerase activity. EOC samples expressing high total hTERT demonstrated significantly lower MCPH1/BRIT1 expression in both tissue (p = 0.05) and primary cultures (p = 0.03). We identified a negative correlation between MCPH1/BRIT1 and α+/β+ hTERT (p = 0.04), and a strong positive association between MCPH1/BRIT1 and both α-/β+ hTERT and α-/β- hTERT (both p = 0.02). A positive association was observed between BRCA1 and α-/β+ hTERT and α-/β- hTERT expression (p = 0.003 and p = 0.04, respectively).

Conclusions: These findings support a regulatory effect of MCPH1/BRIT1 and BRCA1 on telomerase activity, particularly the negative association between MCPH1/BRIT1 and the functional form of hTERT (α+/β+).

Keywords: BRCA1; BRIT1; Epithelial ovarian cancer; MCPH1; Telomerase; hTERT.

MeSH terms

  • BRCA1 Protein / genetics*
  • BRCA1 Protein / metabolism
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Carcinoma, Ovarian Epithelial
  • Cell Cycle Proteins
  • Cell Line, Tumor
  • Cytoskeletal Proteins
  • Female
  • Gene Expression
  • Genes, Tumor Suppressor
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Kaplan-Meier Estimate
  • Neoplasms, Glandular and Epithelial / enzymology
  • Neoplasms, Glandular and Epithelial / genetics*
  • Neoplasms, Glandular and Epithelial / mortality
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism
  • Ovarian Neoplasms / enzymology
  • Ovarian Neoplasms / genetics*
  • Ovarian Neoplasms / mortality
  • Telomerase / genetics*
  • Telomerase / metabolism
  • Transcriptome

Substances

  • BRCA1 Protein
  • BRCA1 protein, human
  • Biomarkers, Tumor
  • Cell Cycle Proteins
  • Cytoskeletal Proteins
  • Isoenzymes
  • MCPH1 protein, human
  • Nerve Tissue Proteins
  • TERT protein, human
  • Telomerase