Mycophenolic acid: an immunostimulant for bladder cancer
The standard treatment to prevent the recurrence and progression of bladder cancer is a topical application of high-dose Mycobacterium bovis bacillus Calmette-Gue ´rin (BCG) [83]. Mycolic acids (MA) (Fig. 6), which is major and essential lipid components of the genus Mycobacterium, has been shown to play a key role in the host immune reaction. Yoshino et al. first reported the anti-tumor effects of purified MAs in animal models. It exerted a distinctive tumor cell growth retardation in vivo through T-cell-dependent antitumor immunity. Simply, MA triggered the collection of various cytokines and MHC class II on the cell surface. Then the immune cells, including CD4+ and CD8+ lymphocytes, NK cells, granulocytes, macrophages, and dendritic cells, were recruited to surround the tumor region and exhibit an immune reaction to the cancer cells. In another report, Kubota et al. had demonstrated that MA induced sufficient humoral response comparable to that of conventional CFA when loaded with antigen (Fig. 7) [84]. Ultimately, after receiving MA, the body tends to develop a Th1-biased mild inflammatory response at the injection site, while CFA induced Th17-biased inflammatory responses are severe and destructive. Therefore, MA is a promising adjuvant candidate material for clinical value of tumor treatment.