resistance to chemotherapy is very important in the prognosis of tumors. transglutaminase-2 (tg-2) mediated chemotherapy resistance has been widely reported. the objective of this study was to demonstrate the effect of 4-hexylresorcinol (4-Hr) on tg-2 activity in nasopharyngeal squamous cell carcinoma cells (KB cells). treatment with a mixture of 4-HR and cisplatin significantly decreased KB cell viability compared to treatment by cisplatin alone at 10 µg/ml (p<0.001). 4-Hr inhibited tg-2

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... ty compared to cisplatin alone at 5, 10 and 20 µg/ml (p=0.001, 0.001 and 0.003, respectively). nuclear translocation of tg-2 was also inhibited by 4-Hr treatment. 4-Hr treatment also increased the fluorescence life-time of DAPI significantly compared to the untreated control or the cisplatin treated group (p<0.001). In conclusion, 4-HR inhibited TG-2 activity and showed a synergistic effect on tumor cell growth inhibition with cisplatin.