IADR Abstract Archives
The Potential of Nicotinamide N-Methyltransferase (NNMT) as an Anti-Cancer Target in Cultured Human Oral Squamous Cancer Cells (OSCC).
Objectives: Oral squamous cell carcinoma (OSCC) is the sixth most common type of cancer in the world and accounts for more than 90% of oral malignancies. Current treatment regimens against OSCC are highly invasive and not always totally satisfactory. The enzyme nicotinamide (NAM) N-methyltransferase (NNMT), is overexpressed in a variety of human cancers, including OSCC, and has been investigated as a potential anticancer target. A recent in-silico investigation to identify inhibitors of NNMT produced several potential candidates. The aim of this project was to; detect if NNMT is expressed in an oral squamous cancer cell line (SCC-4) and dysplastic oral keratinocytes (DOK) and determine the effect of the identified modulators of NNMT on cell viability and cellular respiration, a novel task that has not been done before.
Methods: SCC-4 and DOK cells were cultured as per ATCC recommendations. Cell lysates were prepared and the expression of NNMT was assessed by immunoblot. Cell viability was determined by alamar blue assay. Cellular respiration and extracellular acidification rate were determined by Seahorse XF analyser (Agilent). The NNMT inhibitors used were determined via an in-silico analysis performed by a collaborator (unpublished data) and are named compound 1 and compound 4.
Results: This investigation confirmed the presence of NNMT in both SCC-4 and DOK cells, with no significant difference in enzyme expression between both cell lines. Neither NNMT inhibitor had any significant effect on the viability of either cell line at the concentration range and incubation times used in this study. Significantly, our data has shown that the two NNMT inhibitors studied reduce oxidative phosphorylation and increase glycolysis in DOK and SCC-4 cells.
Conclusions: Our data suggests that NNMT is expressed in both oral squamous cell carcinoma (SCC-4) and dysplastic (DOK) cells. Neither compound had a cytotoxic effect on either cell line at the concentration and incubation times used. The inhibition of NNMT by the selective small molecule inhibitors attenuates cellular respiration and concurrently increases extracellular acidification rate (an indicator of glycolysis), suggesting that the inhibition of NNMT may prove a potential therapeutic target in OSCC.
Methods: SCC-4 and DOK cells were cultured as per ATCC recommendations. Cell lysates were prepared and the expression of NNMT was assessed by immunoblot. Cell viability was determined by alamar blue assay. Cellular respiration and extracellular acidification rate were determined by Seahorse XF analyser (Agilent). The NNMT inhibitors used were determined via an in-silico analysis performed by a collaborator (unpublished data) and are named compound 1 and compound 4.
Results: This investigation confirmed the presence of NNMT in both SCC-4 and DOK cells, with no significant difference in enzyme expression between both cell lines. Neither NNMT inhibitor had any significant effect on the viability of either cell line at the concentration range and incubation times used in this study. Significantly, our data has shown that the two NNMT inhibitors studied reduce oxidative phosphorylation and increase glycolysis in DOK and SCC-4 cells.
Conclusions: Our data suggests that NNMT is expressed in both oral squamous cell carcinoma (SCC-4) and dysplastic (DOK) cells. Neither compound had a cytotoxic effect on either cell line at the concentration and incubation times used. The inhibition of NNMT by the selective small molecule inhibitors attenuates cellular respiration and concurrently increases extracellular acidification rate (an indicator of glycolysis), suggesting that the inhibition of NNMT may prove a potential therapeutic target in OSCC.