Mahmoud Rouabhia
Laval University, Canada
Title: Repeated exposure to cigarette smoke increased gingival fibroblast proliferation, telomerase activity through the activation of cell cycle genes activity
Biography
Biography: Mahmoud Rouabhia
Abstract
The aim of this study was to investigate the effect of repeated exposure to cigarette smoke condensate (CSC) on the survival, oncogenes profiling, telomere length and telomerase activity of primary human gingival fibroblasts.Methods: Primary human gingival fibroblasts were exposed three times a day, during 15 min to CSC at one of the following concentrations: 0, 2, 5 or 10%. The exposure periods were 10, 20 or 30 days. Cell proliferation was evaluated by mean of BrdU assay. Oncogenes & Tumor Suppressor Genes profiling was performed by using PCR Array. Protein telomerase detections were determined by protein telomerase assay. Telomere restriction fragment analysis was performed using the TeloTAGGG Telomere Length Assay Kit. Results: Exposure to low concentrations of CSC led to a significant increase in cell proliferation. CSC modulates the oncogenes pathway increasing CDK4, SRC JUND, NFKBIA and PIK/CA but decreasing other genes such as CASP8, RARA. Tumor suppressor genes pathway mostly showed repressed genes such as BRCA2, WWOX and BRCA1. When analyzing apoptosis genes pathway, multiple genes were repressed including BCL2, MCL1. Apoptotic gene activation is supported by the repression of those genes involved in cell cycling were we found decreased expression of TP53, CCND1 and BRCA2. The telomerase activity was significant (p <0.01) increase in CSC cells, supporting the telomere length shortening. Conclusion: Overall, this study demonstrated that cigarette smoke deregulates cell cycle genes, with potential cell mutation and cancer initiation/ development (funded by the U. Laval Foundation, Fonds Émile-beaulieu).