Doxorubicin is a anti-cancer drugs that interferes with the growth and spread of cancer cells in human body. Doxorubicin is used to treat different types of cancers that affect the ovary, thyoid and lungs, but induced side effect such as nephrotoxicity and cardiotoxicity. Thus, we investigated that the effect of iridin on doxorubicin-induced necrosis in HK-2 cells, a human proximal tubule cell. To confirm effect of iridin on doxorubicin-induced necrosis, HK-2 cells are treated with 10 μM doxorubicin and 80 μM iridin. 80 μM iridin reduced 10 μM doxorubicin-induced necrosis, the mitochondrial over activation and caspase-3 activation. However, iridin reduces anti-cancer effect of doxorubicin such as PARP1 and caspase-3 activation, checkpoint proteins (CDK4 and CDK6) in NCI-H1129 cells (Human non-small cell lung cancer cell). In HCT-116 cells (Human colorectan cancer cell), iridin do not increased protein expression of CDK4 and CDK6 decreased by doxorubicin. Results indicate that treatment of iridin was diminished doxorubicin-induced necrosis in HK-2 cells. However, iridin was decreased anti-cancer effect of doxorubicin on NCI-H1229, but not HCT-116. Thus, further experiment are required to iridin treatment on various cancer cells and animal models because effect of iridin different cell type.

Background: Cynaroside is a flavone, a flavonoid-like compound, known by different names (luteoloside and cinaroside). It is commonly found in Lonicera japonica Thunb., Chrysanthemum moriflium, and Angelica keiskei. The process of cell death has been classified as necrosis and apoptosis. Necrosis refers to unregulated cell death induced by a chemotherapeutic agent. Doxorubicin is an anthracycline anti-cancer drug used to treat acute leukemia, cancer, and lymphoma. However, it induces nephrotoxicity including tubular damage. Therefore, we investigated the protective effect of cynaroside against doxorubicin-induced necrosis in HK-2 cells. Methods and Results: To confirm the beneficial effect of cynaroside on doxorubicin-induced necrosis, HK-2 cells, a human proximal tubule epithelial cell line were treated with 10 μM doxorubicin and 80 μM cynaroside. Doxorubicin treatment resulted in increased DNA fragmentation, caspase-3 activity and mitochondria hyperactivation during cell necrosis. However, pretreatment with 80 μM cynaroside attenuated DNA fragmentation, caspase-3 activity and mitochondria hyperactivation induced by 10 μM doxorubicin in HK-2 cells. Conclusions: These results indicated that pretreatment with cynaroside ameliorated doxorubicin-induced necrosis in HK-2 cells. Therefore, cynaroside be used as a therapeutic agent for improving doxorubicin-induced nephrotoxicity. However, further studies are required to evaluated the toxicity of cynaroside treatment in animals and to determine its protective effect against doxorubicininduced nephrotoxicity in an animal model.