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Identification of the ZAK-MKK4-JNK-TGFβ Signaling Pathway as a Molecular Target for Novel Synthetic Iminoquinone Anticancer Compound BA-TPQ

[ Vol. 13 , Issue. 6 ]


Deng Chen, Wei Wang, Jiang-Jiang Qin, Ming-Hai Wang, Srinivasan Murugesan, Dwayaja H. Nadkarni, Sadanandan E. Velu, Hui Wang and Ruiwen ZhangPages 651-660 (10)


Identification and validation of molecular targets are considered as key elements in new drug discovery and development. We have recently demonstrated that a novel synthetic iminoquinone analog, termed [7-(benzylamino)- 1,3,4,8-tetrahydropyrrolo [4,3, 2-de]quinolin-8(1H)-one] (BA-TPQ), has significant anti-breast cancer activity both in vitro and in vivo, but the underlying molecular mechanisms are not fully understood. Herein, we report the molecular studies for BA-TPQ’s effects on JNK and its upstream and downstream signaling pathways. The compound up-regulates the JNK protein levels by increasing its phosphorylation and decreasing its polyubiquitination-mediated degradation. It activates ZAK at the MAPKKK level and MKK4 at the MAPKK level. It also up-regulates the TGFβ2 mRNA level, which can be abolished by the JNK-specific inhibitor SP600125, but not TGFβ pathway-specific inhibitor SD-208, indicating that both JNK and TGFβ signaling pathways are activated by BA-TPQ and that the JNK pathway activation precedes TGFβ activation. The pro-apoptotic and anti-growth effects of BA-TPQ are significantly blocked by both the JNK and TGFβ pathway inhibitors. In addition, BA-TPQ activates the ZAK-MKK4-JNK pathway in MCF7 cells, but not normal MCF10A cells, demonstrating its cancer-specific activities. In conclusion, our results demonstrate that BA-TPQ activates the ZAK-MKK4-JNK-TGFβ signaling cascade as a molecular target for its anticancer activity.


Apoptosis, ATF3, breast cancer, cancer molecular target, DDIT3, Jun, MAP kinase, synthetic marine drugs, TGFβ, ZAK-MKK4-JNK.


Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 Coulter Drive, Amarillo, TX 79106, USA.

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