[Effect of antisense epidermal growth factor receptor cDNA transfection on telomerase activity of glioblastomas...

Area of Science:

• Molecular biology
• Cancer research
• Genetics

Background:

• Glioblastoma U87MG cells overexpress epidermal growth factor receptor (EGFR).
• EGFR signaling pathways are implicated in cancer progression.
• Telomerase activity and telomere length are critical for cancer cell survival and proliferation.

Purpose of the Study:

• To investigate the impact of antisense EGFR cDNA transfection on telomerase activity and telomere length in glioblastoma U87MG cells.
• To elucidate the underlying molecular mechanisms of EGFR inhibition in glioblastoma suppression.

Main Methods:

• Glioblastoma U87MG cells were transfected with antisense EGFR cDNA constructs.
• Telomerase activity was measured using the Telomeric Repeat Amplification Protocol (TRAP) assay.
• Telomere length was assessed by Southern blot hybridization.
• mRNA expression of hTERT, hTEP1, and c-myc was analyzed via semi-quantitative PCR.

Main Results:

• Antisense EGFR transfection led to reduced EGFR protein levels and decreased responsiveness to EGF stimulation.
• Significant reduction in telomerase activity was observed in antisense EGFR clones.
• Telomere length was shortened in these clones.
• hTERT mRNA expression was slightly decreased, while hTEP1 and c-myc expressions remained unchanged.

Conclusions:

• Antisense EGFR cDNA transfection effectively inhibits the EGFR signaling pathway, leading to decreased telomerase activity and telomere shortening.
• This approach represents a potential new mechanism for tumor suppression in glioblastoma.
• Down-regulation of hTERT mRNA likely contributes to the observed decrease in telomerase activity.