Overexpression of OLC1, cigarette smoke, and human lung tumorigenesis.
Overexpression of OLC1, cigarette smoke, and human lung tumorigenesis.
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DOI：
10.1093/jnci/djn379
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发表时间：
2008-11
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通讯作者：
Jingsong Yuan;Jinfang Ma;Hongwei Zheng;T. Shi;Wenyue Sun;Qiao Zhang;D. Lin;Kaitai Zhang;Jie He;Y. Mao;Xia Gao;Peng Gao;N. Han;G. Fu;T. Xiao;Yan-ning Gao;D. Ma;S. Cheng
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作者：
Jingsong Yuan;Jinfang Ma;Hongwei Zheng;T. Shi;Wenyue Sun;Qiao Zhang;D. Lin;Kaitai Zhang;Jie He;Y. Mao;Xia Gao;Peng Gao;N. Han;G. Fu;T. Xiao;Yan-ning Gao;D. Ma;S. Cheng
背景技术暴露于香烟烟雾是肺癌的主要危险因素，但其如何诱发癌症尚不清楚。肺癌过表达基因 1 (OLC1) 是通过抑制消减杂交鉴定出的 50 个候选肺癌基因之一，在鳞状细胞癌 (SCC) 中的表达高于正常肺上皮细胞。方法 我们使用免疫组织化学 (IHC) 测量 559 名患者的原发性肺癌样本中的 OLC1 蛋白水平，并使用荧光原位杂交测量 23 名患者的原发性鳞状细胞癌样本中的 OLC1 拷贝数。我们使用 Pearson chi(2) 检验比较了 371 名有吸烟史和无吸烟史患者的 SCC 样本中的 OLC1 蛋白表达。我们通过免疫印迹法测定了 H1299 人肺癌细胞、永生化人支气管上皮细胞以及用香烟烟雾冷凝物处理的原代培养的正常人支气管上皮细胞中的 OLC1 蛋白水平。我们使用转染 OLC1 的 NIH3T3 小鼠成纤维细胞（8 只小鼠）测定了无胸腺小鼠中的肿瘤形成，并分析了转染乱序（阴性）或 OLC1 小干扰 RNA (siRNA) 的 H1299 和 H520 肺癌细胞的凋亡和集落形成 (s1)。结果 IHC 检测发现，464 例原发性肺癌中有 387 例 (83.4%) OLC1 蛋白过表达，23 例 SCC 样本中有 14 例 (60%) OLC1 扩增。 OLC1 蛋白过度表达在有吸烟史的 SCC 患者中比无吸烟史的患者更常见（77.1% vs 45.8%，P < .001）。此外，香烟烟雾冷凝物增加了H1299细胞、永生化人支气管上皮细胞和原代培养的正常人支气管上皮细胞中的OLC1蛋白水平。 OLC1 过度表达诱导无胸腺小鼠肿瘤形成（对照与 OLC1，0% vs 100%）。 OLC1 的敲低增加了细胞凋亡（凋亡 H1299 细胞的平均百分比，s1 与阴性：30.3% 与 6.4%，差异 = 23.9%，95% 置信区间 [CI] = 19.1% 至 28.5%，P = 0.002；凋亡 H520 细胞的平均百分比，s1 与阴性：21.6% 与 4.9%，差异= 16.7%，95% CI = 10.6% 至 22.8%，P = .007），集落形成减少（转染 siRNA 的 H1299 细胞集落平均数，阴性 vs s1：84 vs 4，差异 = 80，95% CI = 71 至 88，P < .001；H520 细胞集落平均数转染 siRNA，阴性 vs s1：103 vs 24，差异 = 79，95% CI = 40 至 116，P = .005)。结论 OLC1 是肺癌的候选癌基因，其表达可能受到香烟烟雾暴露的调节。
BACKGROUND Exposure to cigarette smoke is a major risk factor for lung cancer, but how it induces cancer is unclear. The overexpressed in lung cancer 1 (OLC1) gene is one of 50 candidate lung cancer genes identified by suppression subtractive hybridization as having higher expression in squamous cell carcinoma (SCC) than normal lung epithelia. METHODS We used immunohistochemistry (IHC) to measure OLC1 protein levels in primary lung cancer samples from 559 patients and used fluorescence in situ hybridization to measure OLC1 copy number in primary SCC samples from 23 patients. We compared OLC1 protein expression in SCC samples of 371 patients with and without a smoking history using the Pearson chi(2) test. We assayed OLC1 protein levels by immunoblotting in H1299 human lung cancer cells, immortalized human bronchial epithelial cells, and primary cultured normal human bronchial epithelial cells that were treated with cigarette smoke condensate. We assayed tumor formation in athymic mice using NIH3T3 mouse fibroblast cells transfected with OLC1 (eight mice) and analyzed apoptosis and colony formation of H1299 and H520 lung cancer cells transfected with scrambled (negative) or OLC1 small interfering RNAs (siRNAs) (s1). RESULTS OLC1 protein was overexpressed in 387 of 464 (83.4%) of primary lung cancers, as detected by IHC, and OLC1 was amplified in 14 of 23 (60%) of SCC samples. OLC1 protein overexpression was more common in SCC patients with a smoking history than those without (77.1% vs 45.8%, P < .001). In addition, cigarette smoke condensate increased OLC1 protein levels in H1299 cells, immortalized human bronchial epithelial cells, and primary cultured normal human bronchial epithelial cells. Overexpression of OLC1 induced tumor formation in athymic mice (control vs OLC1, 0% vs 100%). Knockdown of OLC1 increased apoptosis (mean percentage of apoptotic H1299 cells, s1 vs negative: 30.3% vs 6.4%, difference = 23.9%, 95% confidence interval [CI] = 19.1% to 28.5%, P = .002; mean percentage of apoptotic H520 cells, s1 vs negative: 21.6% vs 4.9%, difference = 16.7%, 95% CI = 10.6% to 22.8%, P = .007) and decreased colony formation (mean no. of colonies of H1299 cells transfected with siRNAs, negative vs s1: 84 vs 4, difference = 80, 95% CI = 71 to 88, P < .001; mean no. of colonies of H520 cells transfected with siRNAs, negative vs s1: 103 vs 24, difference = 79, 95% CI = 40 to 116, P = .005). CONCLUSIONS OLC1 is a candidate oncogene in lung cancer whose expression may be regulated by exposure to cigarette smoke.