This study aims to investigate the unclear molecular relationship involved in the activation of intrinsic pathway of apoptosis and
NSAID-activated gene-1 (NAG-1) induction as a putative target in
NSAIDs-mediated
chemoprevention of
colorectal cancer. Male Sprague-Dawley rats were administered with a colon-specific pro-
carcinogen,
1,2-dimethylhydrazine dihydrochloride to achieve the early stages of
colorectal cancer. Histopathological examination was performed for the analysis of neoplastic lesions while flow cytometry was performed for the relative quantification of intracellular
reactive oxygen species (ROS), differential mitochondrial membrane potential (
MMP or ΔΨ(M)), and apoptotic events. Various target biomolecules were analyzed either for their
mRNA or
protein expression profiles via RT-PCR and quantitative Real-Time PCR, or Western blotting and immunofluorescence, respectively. Enhanced gene as well as
protein expression of pro-apoptotic agents was observed with the daily
oral administration of two
NSAIDs viz.
Sulindac (
cyclooxygenase (COX)-non-specific) and
Celecoxib (a selective
COX-2 inhibitor). A significant increase in early growth response-1 (EGR-1)
protein expression and nuclear localization in
NSAIDs co-administered animals may have positively regulated the expression of NAG-1 with a significant enhancement of intracellular ROS in turn decreasing the ΔΨ(M) to initiate apoptosis. In silico molecular docking analysis also showed that
Sulindac and
Celecoxib can block the active site pocket of
B-cell lymphoma-extra large (Bcl-xL, anti-apoptotic transmembrane
mitochondrial protein) which could be a putative mechanism followed by these
NSAIDs to overcome anti-apoptotic properties of the molecule.
NSAIDs-mediated up-regulation of EGR-1 and thereby NAG-1 along with implication of higher ROS load may positively regulate the intrinsic pathway of apoptosis for the
chemoprevention of
colorectal cancer.