姜黄素对非小细胞肺癌细胞A549和H460放射敏感性的影响

目的 探讨姜黄素对非小细胞肺癌（NSCLC）细胞A549和H460放射敏感性的影响，并探索长链非编码RNA（lncRNA）同源异型盒基因转录的反义基因间RNA（HOTAIR）在其中的调节机制。 方法 将培养的NSCLC细胞A549和H460根据处理方法的不同，采用4种方式进行分组。（1）分别将NSCLC细胞A549和H460分为6组:0、15、30、60、120和240 μmol/L姜黄素组，采用细胞计数试剂盒8（CCK-8）实验检测各组细胞的增殖活力；（2）分别将NSCLC细胞A549和H460分为8组:0、2、4、6 Gy γ射线照射组及其与30 μmol/L姜黄素联合组，采用CCK-8实验和平板克隆形成实验检测各组细胞的增殖活力；（3）将NSCLC细胞A549分为4组:空白对照组、30 μmol/L姜黄素组、4 Gy γ射线照射组和30 μmol/L姜黄素+4 Gy γ射线照射联合组，采用实时定量聚合酶链反应（qRT-PCR）实验检测各组细胞中5种促癌lncRNA和5种抑癌lncRNA的表达情况；（4）将NSCLC细胞A549分为6组:空白对照组、30 μmol/L姜黄素组、30 μmol/L姜黄素+lncRNA HOTAIR过表达组、4 Gy γ射线照射组、4 Gy γ射线照射+30 μmol/L姜黄素联合组和4 Gy γ射线照射+30 μmol/L姜黄素+lncRNA HOTAIR过表达组，采用CCK-8实验和平板克隆形成实验检测各组细胞的增殖活力。采用学生t检验进行统计学分析。 结果 （1）CCK-8实验结果显示，不同浓度的姜黄素处理可以剂量和时间依赖的方式降低NSCLC细胞A549和H460的增殖活力，且除了15 μmol/L姜黄素作用24 h之外，其余浓度和时间的姜黄素组与对照组相比，差异有统计学意义（t=3.884~5.731，P=0.000~0.043）。（2）CCK-8实验和克隆形成实验结果显示，30 μmol/L姜黄素+不同剂量的γ射线照射联合处理可使γ射线照射单独处理下的NSCLC细胞A549和H460的增殖活力和克隆形成能力进一步降低，差异有统计学意义（t=2.503~12.418，P=0.000~0.044）。（3）qRT-PCR实验结果显示，与空白对照组相比，lncRNA HOTAIR在γ射线单独处理后表达升高（t=3.317，P=0.040），而30 μmol/L姜黄素单独处理和30 μmol/L姜黄素+4 Gy γ射线联合处理均可下调A549细胞中促癌lncRNA HOTAIR的表达（t=3.205、5.916，P=0.038、0.000）。（4）对HOTAIR进行过表达处理，可消除姜黄素对NSCLC细胞A549增殖的抑制并增强其放射敏感性（t=3.584~5.802，P=0.000~0.004）。 结论 姜黄素可以通过下调促癌lncRNA HOTAIR的表达从而抑制NSCLC细胞的增殖活力，并增强其放射敏感性。

Effects of curcumin on the radiosensitivity of non-small cell lung cancer A549 and H460 cells

Objective To explore the effects of curcumin on the radiosensitivity of non-small cell lung cancer (NSCLC) A549 and H460 cells and determine the underlying mechanism as mediated by long non-coding RNA (lncRNA) homeotic complex gene anti-sense intergenic RNA (HOTAIR). Methods NSCLC were divided into different groups according to the experimental scheme. (1) A549 and H460 cells were divided into six groups each treated by 0, 15, 30, 60, and 240 μmol/L curcumin. Cell-counting kit 8 (CCK-8) assay was performed to measure the cell viability after each treatment. (2) A549 and H460 cells were divided into eight groups of 0, 2, 4, and 6 Gy γ-irradiation treatment groups and their corresponding combinations with 30 μmol/L curcumin. CCK-8 and colony formation assays were conducted to determine the cell proliferative abilities of each group. (3) A549 cells were divided into four groups: control, 30 μmol/L curcumin treatment, 4 Gy γ-irradiation treatment, and combinational treatment of 30 μmol/L curcumin and 4 Gy γ-irradiation groups. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to monitor the expression levels of five oncogenic lncRNAs and five tumor-suppressive lncRNAs in A549 cells from each group. (4) A549 cells were divided into six groups: control, 30 μmol/L curcumin treatment, 30 μmol/L curcumin+overexpression of lncRNA HOTAIR, 4 Gy γ-irradiation treatment, combinational treatment of 30 μmol/L curcumin and 4 Gy γ-irradiation, and combinational treatment of 30 μmol/L curcumin and 4 Gy γ-irradiation+overexpression of lncRNA HOTAIR groups. The cell proliferative capacities after each treatment were detected by CCK-8 and colony formation assays. Statistical significance was determined by SPSS statistical software and analyzed by Student t-test. Results (1) CCK-8 assay results showed that curcumin treatment decreased the cell viability of A549 and H460 cells in a dose- and time-dependent manner, and the difference between each treatment group and the control group was statistically significant (t=3.884 –5.731, P=0.000–0.043). (2) CCK-8 and colony formation assay revealed that the combinational treatment of 30 μmol/L curcumin and different γ-irradiation doses significantly promoted the further reduction of cell proliferation and colony formation abilities compared with γ-irradiation alone (t=2.503–12.418, P=0.000–0.044). (3) qRT-PCR detection revealed that the expression level of lncRNA HOTAIR elevated after γ-irradiation treatment (t=3.317, P =0.040), but the sole treatment of 30 μmol/L curcumin and the combinational treatment of 30 μmol/L curcumin with γ-irradiation could down-regulate the expression of tumor-promoting lncRNA HOTAIR in A549 cells compared with the control group (t=3.205, 5.916, P=0.038, 0.000). (4) HOTAIR overexpression could reverse the inhibitory effects of curcumin on the cell proliferation capacity and radiation resistance of A549 cells (t＝3.584–5.802, P=0.000–0.004). Conclusion Curcumin can suppress the cell proliferation capacity and enhance the radiation sensitivity of NSCLC by down-regulating lncRNA HOTAIR.