ผลของคูซูโนคินินต่อระดับโปรตีนที่เกี่ยวข้องกับกระบวนการเกิดมะเร็งเต้านมในหนูขาว

Abstract

Kusunokinin, a lignin compound from Piper nigrum, shows an antiproliferation and induction of apoptosis on breast cancer cells. Moreover, in vivo study found that kusunokinin inhibited the growth of tumor volume in Sprague-Dawley rats. However, the previous study provides insufficient data of molecular mechanism of kusunokinin. Therefore, this work was aimed to study the molecular mechanism of kusunokinin in N-nitroso-N-methylurea (NMU) induced mammary tumor Sprague-Dawley rats. After tumor was found, rats were treated with 7 and 14 mg/kg of kusunokinin or 0.5 mg/kg of doxorubicin (an ineffective dose) or the combination of 0.5 mg/kg doxorubicin with 7 mg/kg of kusunokinin for 14 days. Then, protein levels of cell cycle, proliferation, angiogenesis, and migration in mammary tumor tissue were investigated using Western blot analysis. Proteins in four pathways were determined including proliferation (c-Src, PI3K, Akt, p-Erk1/2, Erk1/2, p-STAT5, STAT5 and Wnt-4), cell cycle (E2f-1 and Cyclin D1), angiogenesis (VEGF) and migration (E-cadherin, MMP-2 and MMP-9). The results showed that 14 mg/kg of kusunokinin inhibited phosphorylation of Erk1/2 and c-Src, and tended to decrease protein levels of PI3K, Akt, and E2f-1 which were associated in cell cycle and proliferation. Surprisingly, doxorubicin alone and the combination with kusunokinin showed a significant difference in p-Erk1/2 protein. Furthermore, kusunokinin also reduced the protein level in angiogenesis, VEGF, but did not showed a significant different. For migration pathway, 14 mg/kg of kusunokinin showed significantly suppressed the protein levels of E-cadherin and MMP-9. Finally, the inhibition of cell migration of kusunokinin was confirmed in MCF-7 cells using Wound healing assay. The results showed that kusunokinin at 0.286 and 0.571 μg/mL inhibited the migration of MCF-7 cells in a dose-dependent manner. These results suggest that the molecular mechanism of kusunokinin, might be through the suppression of protein in proliferation and migration pathways via down-regulation of c-Src, p-Erk1/2, E-cadherin and MMP-9. The outcome from this study will be provided the necessary information of kusunokinin in developing a specific targets therapeutic drugs for breast cancer.