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.