Patel Vyomesh, Lahusen Tyler, Leethanakul Chidchanok, Igishi Tadashi, Kremer Marcus, Quintanilla-Martinez Leticia, Ensley John F, Sausville Edward A, Gutkind J Silvio, Senderowicz Adrian M
Oral & Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
Clin Cancer Res. 2002 Nov;8(11):3549-60.
Altered and deregulated cyclin-dependent kinase (cdk) activity is now believed to play a major role in the pathogenesis of head and neck squamous cell carcinomas (HNSCC), thus providing a suitable cellular target for therapeutic intervention. UCN-01 (7-hydroxy-staurosporine), a known protein kinase C and cdk modulator, demonstrates antiproliferative and antitumor properties in many experimental tumor models and may represent a potential candidate to test in HNSCC. In this study, UCN-01 displayed potent antiproliferative properties (IC50 of approximately 17-80 nM) in HNSCC cells. Cell cycle analysis revealed that UCN-01 treatment of HNSCC cells for 24 h leads to a G1 block with a concomitant loss of cells in S and G2-M and the emerging sub-G1 cell population, confirmed to be apoptotic by terminal deoxynucleotidyl transferase-mediated nick end labeling analysis. Additional in vitro studies demonstrated a G1 arrest that was preceded by depletion in cyclin D3, elevation of p21(WAF1) and p27(KIP1) leading to a loss in activity of G1 cdks (cdk2, cdk4), and reduction in pRb phosphorylation. Antitumor properties of UCN-01 were also assessed in vivo by treating HN12 xenografts (7.5 mg/kg/i.p./daily) with UCN-01 for 5 consecutive days. Total sustained abolition of tumor growth (P < 0.00001) was obtained with only one cycle of UCN-01 treatment. Terminal deoxynucleotidyl transferase-mediated nick end labeling staining of xenograft samples revealed a higher incidence of apoptosis in treated tissues when compared with control. Additional tissue analysis demonstrated that elevated p27(KIP1) with minimal increase in p21(WAF1) and reduced cyclin D3 levels were readily detected in those animals treated with UCN-01, similar to those observed in HNSCC cells. Thus, UCN-01 exhibits both in vitro and in vivo antitumor properties in HNSCC models, and these effects are associated with a decrease in cyclin D3 and an increase in p27(KIP1) protein levels, thus providing appropriate surrogate markers to follow treatment efficacy in vivo and, therefore, a suitable drug candidate for treating HNSCC patients.
目前认为，细胞周期蛋白依赖性激酶（cdk）活性的改变和失调在头颈部鳞状细胞癌（HNSCC）的发病机制中起主要作用，因此为治疗干预提供了合适的细胞靶点。UCN-01（7-羟基-星孢菌素）是一种已知的蛋白激酶C和cdk调节剂，在许多实验性肿瘤模型中显示出抗增殖和抗肿瘤特性，可能是在HNSCC中进行测试的潜在候选药物。在本研究中，UCN-01在HNSCC细胞中表现出强大的抗增殖特性（IC50约为17-80 nM）。细胞周期分析显示，用UCN-01处理HNSCC细胞24小时会导致G1期阻滞，同时S期和G2-M期细胞减少，出现亚G1期细胞群，通过末端脱氧核苷酸转移酶介导的缺口末端标记分析证实为凋亡细胞。额外的体外研究表明，G1期阻滞之前，细胞周期蛋白D3减少，p21（WAF1）和p27（KIP1）升高，导致G1期cdk（cdk2、cdk4）活性丧失，以及pRb磷酸化减少。通过连续5天用UCN-01处理HN12异种移植瘤（7.5 mg/kg/腹腔注射/每日），还在体内评估了UCN-01的抗肿瘤特性。仅一个周期的UCN-01治疗就实现了肿瘤生长的完全持续抑制（P < 0.00001）。与对照相比，异种移植瘤样本的末端脱氧核苷酸转移酶介导的缺口末端标记染色显示，治疗组织中的凋亡发生率更高。额外的组织分析表明，在用UCN-01治疗的动物中，很容易检测到p27（KIP1）升高，p21（WAF1）略有增加，细胞周期蛋白D3水平降低，这与在HNSCC细胞中观察到的情况相似。因此，UCN-01在HNSCC模型中表现出体外和体内抗肿瘤特性，这些作用与细胞周期蛋白D3减少和p27（KIP1）蛋白水平增加有关，从而为监测体内治疗效果提供了合适的替代标志物，因此是治疗HNSCC患者的合适候选药物。
