(‐)‐Epigallocatechin 3‐gallate (EGCG) is a potent antioxidant polyphenol in green tea that acts as an anticancer agent via both direct and indirect pathways. Although the relationship between EGCG’s anticancer effects and its antioxidant activity is not fully understood, it is known that EGCG stimulates production of reactive oxygen species (ROS), which induce oxidative stress leading to cell death. In IM9 multiple myeloma cells, EGCG acted in a dose‐ and time‐dependent manner to induce apoptotic cell death. Among the antioxidant enzymes expressed in IM9 cells, levels of peroxiredoxin (Prdx) V were selectively and significantly reduced by EGCG. Moreover, the ROS scavenger NAC completely inhibited EGCG‐induced apoptosis and PrdxV reduction, while overexpression of PrdxV, but not a PrdxVC48S mutant, protected IM9 cells from EGCG‐induced apoptosis. EGCG‐induced reductions in cell viability and PrdxV levels were also observed in primary CD138+ multiple myeloma cells from patients. These results suggest that PrdxV is a key target via which EGCG mediates its anticancer effects.

• Tae‐Hoon Lee(Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University)
• Hee‐Young Yang(Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University)
• Hoon‐In Choi(Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University)
• Ung Yang(Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University)
• Kyoung‐Jin Chung(Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University)
• Lina Ren(Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University)