Investigation of P53 and TTC5 function in lung cancer

Menendez Creamer, Delta Patricia

Abstract

Lung cancer represents 11.6% of the total cases with patients destined for a poor outcome due to late-stage detection, therefore it is important to find new approaches to detect and treat this disease. Current evidence suggests a role of p53 gene and TTC5/STRAP (co-factor of p53) in this cancer and that TTC5 is also associated with clinicopathological features.
To determine if TTC5 and p53 proteins play a role in lung cancer, immunohistochemistry method was adapted to analyse 100 patient’s samples. In addition, markers of EMT, migration and metastasis S100A4 and E-cadherin were used. Protein expression (positive/negative) and protein intensities (weak, moderate, strong) were correlated with clinicopathological features including gender, age, tumour stage (T), node presence (N) and metastasis (M). Chi square-based analysis revealed that TTC5 maybe associated with non-metastatic cancer. In addition, younger age seems to be positively correlated with E- cadherin protein expression. Correlations between different protein expression intensities were positive, with significant correlations between p53, TTC5 and E-cadherin, TTC5, S100A4 and E-cadherin, S100A4 and E-cadherin. The strongest positive correlation was between p53 and TTC5 whereas the weakest and non-significant correlation was between p53 and S100A4.
To determine how p53 pathway affects cell growth and cell migration, A549, BEAS-2b and NCI-H2170 cell line were used. Cells were treated with etoposide and cisplatin, in order to measure cell viability, cell migration, protein and mRNA expression. siRNA method was used to silence TTC5 expression to determine its effect on cell viability, migration, and migration markers S100A4 and E-cadherin. IC50 value of 4.91μM was obtained in A549 cells not transfected with TTC5 specific siRNA and treated with etoposide, whereas substantially higher IC50 value of 25.39μM was measured in cells with TTC5 expression inhibited, suggesting that TTC5 may have anti-proliferative role in lung cancer and may be important for response to etoposide chemotherapy.
Effects of TTC5 inhibition on A549 cell migration indicated that TTC5 may have inhibitory effect on cell migration. However, TTC5 knockdown was associated with downregulation of S100A4 gene expression and E-cadherin expression downregulation trend.
Overall, these results suggest complex involvement of p53/TTC5 pathway and lung cancer and highlight the possibility that TTC5 may play a dual role in lung cancer and metastasis development.

• Thesis Type: Thesis
• Deposit Date: Aug 15, 2024
• Publicly Available Date: Sep 27, 2026
• Award Date: Sep 26, 2024