title: Activation of PI3K/Akt/IKK-alpha/NF-kappaB signaling pathway is required for the apoptosis-evasion in human salivary adenoid cystic carcinoma: its inhibition by quercetin.
abstract: Quercetin, one of the most common natural flavonoids, has been reported to possess significant anti-tumor activities both in vitro and in vivo. The present study was to investigate the effects of quercetin on growth and apoptosis in human salivary adenoid cystic carcinoma (ACC). The result from MTT assay showed that quercetin decreased cell viability of both low metastatic cell line ACC-2 and high metastatic cell line ACC-M in a concentration- and time-dependent manner. Moreover, treatment with quercetin resulted in significantly increased apoptosis in ACC cells. Our data also revealed that the apoptosis induced by quercetin treatment was through a mitochondria-dependent pathway which showed close correlation with the down-regulation of the PI3K/Akt/IKK-alpha/NF-kappaB pathway. Most importantly, quercetin significantly prevented in vivo growth of ACC xenografts in nude mice, accompanied by induction of tumor cell apoptosis, suppression of NF-kappaB nuclear translocation, as well as down-regulation of Akt and IKK-alpha activation. In addition, we explored the clinical significance of the PI3K/Akt/IKK-alpha/NF-kappaB signaling axis in ACC by immunohistochemical analysis of tissue specimens followed by the clustering analyses. We determined that the PI3K/Akt/IKK-alpha/NF-kappaB pathway is ubiquitously activated in ACC and plays an essential role in the evasion of apoptosis. Taken together, the results from our study implicated that quercetin would be a promising chemotherapeutic agent against ACC through its function of down-regulating the PI3K/Akt/IKK-alpha/NF-kappaB signaling pathway.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China. zhijundejia@yahoo.cn
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Sun
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Xiang
authors.initials: X
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Ling-Xin
authors.initials: LX
authors.lastname: Zhu
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis; D003528:Carcinoma, Adenoid Cystic / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011794:Quercetin / Q000633:toxicity*; D012468:Salivary Gland Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D020169:Caspases; D045304:Cytochromes c; D051550:I-kappa B Kinase; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2; D011794:Quercetin