Visfatin, an adipokine secreted by cells, is crucial for intracellular nicotinamide adenine dinucleotide+ biosynthesis. Extracellularly, visfatin plays diverse roles in inflammatory conditions, including obesity, which is closely linked to osteoclastogenesis. We previously showed that visfatin enhances receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis in bone marrow-derived macrophages. However, its enzymatic activity during this process is poorly understood. Here, we investigated visfatin’s effects on RANKL-induced osteoclast differentiation. Our results demonstrate that visfatin promotes this differentiation, an effect inhibited by FK866, an inhibitor of visfatin’s enzymatic activity. Furthermore, FK866 also inhibited RANKL-induced osteoclast differentiation. These findings suggest that inhibiting visfatin’s enzymatic activity modulates osteoclast differentiation. Thus, visfatin plays an important role in osteoclastogenesis, both intracellularly and extracellularly, and FK866 has therapeutic potential for diseases characterized by imbalanced osteoclast formation, such as osteoporosis and periodontitis.

Visfatin is a pro-inflammatory cytokine, which is thought to play a central role in systemic inflammation and the pathogenesis of obesity related diseases. Only a few studies investigated the effect of visfatin on human cancers. Furthermore, there have been no studies on the association between the expression of visfatin in OSCC tissue and its effect on OSCC patients. Hence, the present study analyzed the expression of visfatin in OSCC from Korean patients. Immunohistochemistry for visfatin was performed using 12 normal oral mucosas (NOM), 16 oral leukoplakias (with/without dysplasia), and 58 OSCC patients samples. Immunoreactivity was semi-quantitatively scored and the correlation between the expression of visfatin and clinicopathological parameters of OSCC patients was analyzed. The immunohistochemical analysis demonstrated that the expression level of visfatin increased in OSCC alone (p<0.05). Moreover, the immunoexpression score of visfatin was significantly correlated with TNM stage of OSCC patients. Our findings suggested that visfatin can play a certain role in the pathogenesis of OSCC. In addition, visfatin was associated with the tumor progression of OSCC patients and may act as independent biomarker of OSCC.