Anticancer efficacy of 5F in NNK-induced lung cancer development of A/J mice and human lung cancer cells

• Published in: Journal of molecular medicine (Berlin, Germany) Germany), 2010-12, Vol.88 (12), p.1265-1276
• Main Authors: Li, Ming-Yue, Leung, Jackie, Kong, Angel W. Y., Liang, Nian Ci, Wu, Kefeng, Hsin, Michael K. Y., Deng, Yi Feng, Gong, Xianling, Lv, Yingnian, Mok, Tony S. K., Underwood, Malcolm J., Chen, George G.
• Format: Article
• Language: English
• Subjects: Animals; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; Antineoplastic Agents - therapeutic use; Apoptosis - drug effects; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cell Cycle - drug effects; Cell Nucleus - drug effects; Cell Nucleus - enzymology; Cell Proliferation - drug effects; Cell Survival - drug effects; Disease Models, Animal; Diterpenes - chemistry; Diterpenes - pharmacology; Diterpenes - therapeutic use; Dose-Response Relationship, Drug; Down-Regulation - drug effects; Drug Screening Assays, Antitumor; Extracellular Signal-Regulated MAP Kinases - metabolism; General aspects; Human Genetics; Humans; Internal Medicine; Lung cancer; Lung Neoplasms - drug therapy; Lung Neoplasms - enzymology; Lung Neoplasms - pathology; Medical sciences; Mice; Mitochondria - drug effects; Mitochondria - metabolism; Molecular Medicine; Nitrosamines; Original Article; Pneumology; Protein Transport - drug effects; Proto-Oncogene Proteins c-akt - metabolism; Time Factors; Treatment Outcome; Tumors of the respiratory system and mediastinum; Up-Regulation - drug effects
• ISSN: 0946-2716; 1432-1440
• DOI: 10.1007/s00109-010-0676-4

The mechanism responsible for the apoptotic effect induced by ent-11α-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F) is not fully understood and its in vivo effect has not been tested. In this study, the effect and mechanism of 5F was investigated in cigarette smoking carcinogen 4-methylnitrosamino-1-3-pyridyl-butanone (NNK)-induced mouse lung tumor model and in cultured lung cancer cells NCI-H23 and CRL-2066. 5F were given to mice after they were treated with NNK for 18 weeks. The effect of 5F on the lung tumor formation was examined, and its side effect was monitored. Cell proliferation and apoptosis were determined through expression of PCNA, Bcl-2, Bax, and TUNEL assay in in vivo animal model. 5F significantly inhibited the NNK-induced lung tumors by inducing apoptosis and suppressing cell proliferation in vivo with minimal side effects. Cell culture experiments showed that 5F translocated Bax into the mitochondria, downregulated Bcl-2, activated caspase-9 and caspase-3, released cytochrome c into the cytosol, and translocated AIF from the mitochondria to the nucleus, which leading to G2-M cell cycle arrest and cell apoptosis. 5F also activated ERK1/2 and the inhibition of ERK1/2 suppressed 5F-mediated changes in apoptotic molecules. In addition to ERK1/2, 5F activated Akt. The inhibition of Akt further facilitated the apoptosis induced, suggesting that Akt activation was anti-apoptotic rather than pro-apoptotic. Collectively, 5F is effective against lung cancer in vivo with minimal side effects. It induces apoptosis in lung cancer through the mitochondrial-mediated pathway, in which the activation of ERK is critical.