Sirt1通路在矢车菊素-3-葡萄糖苷抗乳腺癌细胞上皮间质转化中的意义

Phytochemicals Cyanidin-3-glucoside (C3G) was reported to have anti-cancer effects but the mechanism remains unknown. Our previous studies have found that C3G inhibit epithelial-mesenchymal transition (EMT) of breast cancer cells. Meanwhile, C3G up-regulates the expression of SIRT1, and dependent on the intracellular concentration of free Ca2+ and AMPK. We speculate that C3G exerts anti-EMT effect in breast cancer cells by upregulating intracellular concentration of free Ca2+ as well as the activation of Ca2+-dependent AMPK, then increased SIRT1 expression and deacetylation regulation downstream molecule, ultimately inhibit EMT, migration and invasion of breast cancer cells. Topics to be first in the breast cancer xenografts nude mice treated with C3G, to observe the growth and metastasis of breast cancer xenografts, intracellular concentration of free Ca2+, the activation of Ca2+-dependent AMPK as well as the expression of SIRT1; then analysis the mechanism in breast cancer cells through which C3G up-regulates the intracellular concentration of free Ca2+ /AMPK, SIRT1 expression levels, deacetylation regulation downstream molecule. Finally, through inhibiting the Ca2+ influx , AMPK activation and SIRT1 activation, find out the anti migration and invasion mechanism of C3G. This research will provide experimental basis for elucidating the mechanism of C3G preventing breast cancer cells invasion and metastasis, and provide theoretical and experimental basis for C3G prevention and treatment of breast cancer.

植物化学物矢车菊素-3-葡萄糖苷(Cyanidin-3-glucoside，C3G)具有抗癌作用，但作用机制尚未明确。课题组前期研究发现，C3G可抑制乳腺癌细胞EMT，迁移和侵袭；C3G可通过促进Sirt1表达抑制上述过程，Ca2+和AMPK抑制剂部分逆转其效应。基于此，提出如下假说：C3G抑制乳腺癌的EMT，机理可能为：C3G上调乳腺癌细胞内Ca2+浓度诱导AMPK活性增加，从而增强Sirt1的表达，后者通过去乙酰化Smad4，抑制MMP7等，最终抑制乳腺癌细胞的EMT，迁移和侵袭。课题拟运用细胞生物学、分子生物学及裸鼠肿瘤接种等方法从整体动物、细胞及分子水平展开研究。研究结果可以明确C3G防治乳腺癌的机制，并可为其临床应用提供实验依据。

三阴性乳腺癌（TNBC）是一组异质性乳腺癌，具有明显的转移性、复发率高、生存期短等特点。上皮-间质转化（EMT）与肿瘤转移密切相关。矢车菊素-3-葡萄糖苷（C3G）是新鲜水果和蔬菜中最丰富的花青素色素，具有很好的抗氧化性。C3G也能抑制肿瘤细胞的某些恶性生物行为，但其抑癌作用尤其是TNBC是否与抑制EMT有关尚不清楚。在此，本课题组发现C3G降低了TNBC细胞系MDA-MB-231和BT-549细胞的迁移和侵袭性。在机制上，C3G诱导EMT逆转，表现为上皮标记物E-ca和ZO-1增加，间充质标记物Vimentin、N-ca减少和EMT相关转录因子Snail1、Snail2减少。NF-kB是EMT的关键，Sirt1对NF-kB有抑制作用。课题组发现，C3G对三阴性乳腺癌细胞的NF-kB和Sirt1分别有抑制作用和诱导作用。后来的证据表明，小干扰RNA转染一直Sirt1后，C3G对NF-kB的抑制作用和EMT的逆转作用均被减弱。随后，课题组发现microRNA-138（miR-138）通过mRNA翻译抑制抑制Sirt1的表达，C3G对miR-138有抑制作用。而且miR-138的抑制作用与C3G激活Sirt1、抑制TNBC细胞迁移和侵袭有关。总体来看，课题组为C3G的抗乳腺癌机制提供了更多的证据，并可为其临床应用提供实验依据。