Section of General Thoracic Surgery, Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado School of Medicine, Aurora, CO, USA.
J Thorac Cardiovasc Surg. 2012 Nov;144(5):1185-91. doi: 10.1016/j.jtcvs.2012.08.003.
Group IIa secretory phospholipase A2 (sPLA2 IIa) plays a role in the malignant potential of several epithelial cancers. Nuclear factor kappa B (NF-κB) regulates cancer cell growth and is modulated by phospholipase activity in many cancer cells. We hypothesized that knockdown of sPLA2 in lung cancer cells would reduce cell proliferation and NF-κB activity in vitro and attenuate tumor growth in vivo.
Two human non-small cell lung cancer cell lines (A549 and H358) were transduced with short hairpin RNA targeting sPLA2 group IIa. Quantitative reverse transcriptase-polymerase chain reaction and immunoblotting confirmed knockdown of sPLA2 IIa messenger RNA and protein, respectively. Cell proliferation was evaluated by the 5-bromo-2'-deoxyuridine DNA labeling assay. NF-κB phosphorylation was assayed by western blot. 1 × 10(6) of A549 or A549 sPLA2 knockdown cells were injected into the left flanks of nude mice (aged 6 to 8 weeks). Tumors were followed for 23 days, then removed and stained with hematoxylin and eosin, stained with Ki-67, and analyzed for sPLA2 IIa messenger RNA expression.
sPLA2 knockdown reduced NF-κB phosphorylation and tumor growth in vivo. A549 wild-type tumors grew twice as fast as knockdown tumors. Ki-67 staining was more prominent throughout the wild-type tumors compared with knockdown tumors. Explanted knockdown tumors maintained lower sPLA2 levels compared with wild-type, confirmed by reverse transcriptase-polymerase chain reaction.
Knockdown of sPLA2 IIa suppresses lung cancer growth in part by attenuating NF-κB activity. These findings justify further investigation into the cellular mechanisms of sPLA2 in lung cancer and its potential role as a therapeutic target.
IIa 组分泌型磷脂酶 A2（sPLA2 IIa）在几种上皮癌的恶性潜能中发挥作用。核因子 kappa B（NF-κB）调节癌细胞的生长，并在许多癌细胞中受到磷脂酶活性的调节。我们假设在肺癌细胞中敲低 sPLA2 将减少体外细胞增殖和 NF-κB 活性，并减轻体内肿瘤生长。
用靶向 sPLA2 组 IIa 的短发夹 RNA 转导两种人非小细胞肺癌细胞系（A549 和 H358）。定量逆转录-聚合酶链反应和免疫印迹分别证实了 sPLA2 IIa 信使 RNA 和蛋白质的敲低。通过 5-溴-2'-脱氧尿苷 DNA 标记测定法评估细胞增殖。通过 Western blot 测定 NF-κB 磷酸化。将 1×10（6）个 A549 或 A549 sPLA2 敲低细胞注射到裸鼠（6-8 周龄）的左侧侧翼。跟踪肿瘤 23 天，然后取出并进行苏木精和伊红染色、Ki-67 染色，并分析 sPLA2 IIa 信使 RNA 表达。
sPLA2 敲低降低了 NF-κB 磷酸化和体内肿瘤生长。A549 野生型肿瘤的生长速度是敲低肿瘤的两倍。与敲低肿瘤相比，Ki-67 染色在整个野生型肿瘤中更为明显。与野生型相比，植入的敲低肿瘤中 sPLA2 水平保持较低，这通过逆转录-聚合酶链反应得到证实。
sPLA2 IIa 的敲低部分通过减弱 NF-κB 活性抑制肺癌生长。这些发现证明了进一步研究 sPLA2 在肺癌中的细胞机制及其作为治疗靶点的潜在作用是合理的。
