Background:

Oleanolic acid (Caryophyllin) is a natural compound from plants with anti-tumor activities.

Oleanolic acid (OA) suppresses the proliferation of lung cancer cells in both dose- and time-dependent manners, along with an increase in miR-122 abundance. CCNG1 and MEF2D, two putative miR-122 targets, are found to be downregulated by OA treatment [1]. OA induces autophagy in normal tissue-derived cells without cytotoxicity. OA-induced autophagy is shown to decrease the proliferation of KRAS-transformed normal cells and to impair their invasion and anchorage-independent growth[2].

Mouse model experiments also demonstrat that OA suppresses the growth of KRAS-transformed breast epithelial cell MCF10A-derived tumor xenograft by inducing autophagy [2]. Activation of MAPK pathways, including p-38 MAPK, JNK and ERK, is triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. OA induces p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibits Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event is indispensable for p38 MAPK-dependent apoptosis in cancer cells[3].It is also proved that p38 MAPK knockdown A549 tumors are resistant to the growth-inhibitory effect of OA[3]. In OA-treated EAM mice the number of Treg cells and the production of IL-10 and IL-35 are markedly increased, while proinflammatory and profibrotic cytokines are significantly reduced[4].

参考文献:
[1]. Zhao X, et al. Oleanolic acid suppresses the proliferation of lung carcinoma cells by miR-122/Cyclin G1/MEF2D axis. Mol Cell Biochem. 2015 Feb;400(1-2):1-7.
[2]. Liu J, et al. Oleanolic acid inhibits proliferation and invasiveness of Kras-transformed cells via autophagy. J Nutr Biochem. 2014 Nov;25(11):1154-60.
[3]. Liu J, et al. p38 MAPK signaling mediates mitochondrial apoptosis in cancer cells induced by oleanolic acid. Asian Pac J Cancer Prev. 2014;15(11):4519-25.
[4]. Martín R, et al. Oleanolic acid modulates the immune-inflammatory response in mice with experimental autoimmune myocarditis and protects from cardiac injury. Therapeutic implications for the human disease. J Mol Cell Cardiol. 2014 Jul;72:250-62.