Oral cancer accounts for 3-5% of all cancers worldwide. The present study was
undertaken to investigate the correlation between overexpression of
cyclooxygenase-2 (COX-2) and various grades of oral cancer, and to ascertain
the inhibitory effect of propolis in the human oral carcinoma cell line. For
ex vivo studies, 45 patients with oral submucous fibrosis (OSF; n=15), oral
leukoplakia (OLP; n=18) and oral squamous cell carcinoma (OSCC; n=18) were
recruited, and a biopsy was done to determine COX-2 protein expression by
Western blotting and immunohistochemistry (IHC). For the in vitro study,
COX-2 levels were measured in human oral epidermal carcinoma cell line by
immune blotting and IHC. The results of ex vivo studies by Western blotting
revealed that COX-2 protein levels were highly upregulated in OSCC tissue,
followed by OLP and OSF. The levels of COX-2 expression also showed a
positive correlation with the grade (severity) of each oral precancerous and
cancerous condition. Immunohistochemistry analysis revealed the presence of
intense COX-2 staining in the cells of OSCC tissue, equivalent to the OLP and
OSF specimens. In the in vitro study of oral carcinoma KB cells, Western
blotting and IHC analysis showed that caffeic acid phenyl ester (CAPE)-rich
propolis and celecoxib, a standard COX-2 inhibitor, markedly downregulated
COX-2 expression. These results suggest that propolis exhibits a
chemopreventive potential by lowering COX-2 expression in the oral carcinoma
KB cell line. Hence, propolis might be used as an adjuvant therapy for
treating oral cancer with standard chemotherapy drugs.
The anti-tumoral effects of different local anesthetics on human endometrial carcinoma cell line: An in-vitro study