以 Cisplatin 誘導腎毒性之小鼠為動物模式探討異厚圤酚對細胞骨架及細胞極性之影響

Abstract

Cisplatin or cis-diamminedichloroplatinum (II) has been used as an anti-cancer drug since 1970s. It is proven to be an effective therapeutic agent in treating head, neck, lung, bladder, and germ cell cancers. Unfortunately, the accompanied nephrotoxicity compromises its wide applications at clinics. The incidence of Cisplatin-induced nephrotoxicity or acute kidney injury ranges from 20%-30% following a single administration. Furthermore, the severity of Cisplatin- induced nephrotoxicity increases with repeated treatments/doses, thus often impede the cancer treatment. Although the exact mechanism that is responsible for Cisplatin-induced nephrotoxicity is not fully understood; however, the induction of oxidative stress and the activation of inflammatory responses might be involved. Honokiol, a polyphenol constituent extracted from the bark of Magnolia obovate or Magnolia officinalis, exhibits several important bioactivities, including anti-oxidation, anti-allergy, anti-anxiety, anti-cancer, anti-depression, and neuroprotection. Moreover, recent studies showed that Honokiol exhibits anti-inflammation and antioxidant effects in numbers of in vitro and in vivo models. In this study, we applied in vivo Cisplatin-induced kidney injury mouse model and in vitro Madin-Darby Canine Kidney Epithelial Cells (MDCK) cell culture-based analyses to investigate whether Honokiol exhibits the protective effects on kidney function. By applying various independent techniques, we investigated the relationship and changes between the cytoskeletons (actin and tubulin), and two important cell polarity maintaining proteins, E-cadherin and Occludin, upon Cisplatin and/or Honokiol challenges. First we demonstrated that Cisplatin can disrupt the localization of E-cadherin and Occludin in MDCK cells. Second, we disclosed a new property of Honokiol on its ability to stabilize cellular junction proteins against Cisplatin-induced alteration. Furthermore, Honokiol slightly increased the amount of F-actin and expended the structure of microtubule, which likely contributed to the maintenance of cellular localization of E-cadherin and Occludin at the cellular junctions. More importantly, Honokiol attenuated Cisplatin-induced nephrotoxicity in our animal model. Honokiol treatment not only preserved the basic kidney functions and structures, but also reduced the interstitial fibrosis and inflammation in general. Although we expected that Honokiol achieved its protective effect by its anti-oxidation and anti-apoptosis abilities, but immunolabeling of oxidative stress marker protein 8-hydroxy-deoxy-guanidine (8-OHdG) and apoptosis marker Caspase-3 didn’t fully support our speculations. Nevertheless, based on our results, Honokiol seems to be a promising candidate to be given along with Cisplatin to reduce the cyto-/ organ toxicity of Cisplatin and to improve the clinical safety of Cisplatin usage in cancer patients.