Non-small-cell lung cancers with kinase domain mutations in the epidermal growth factor receptor are sensitive to ionizing radiation

Non-small cell lung cancers (NSCLCs) bearing mutations in the tyrosine kinase domain (TKD) of the epidermal growth factor receptor (EGFR) often exhibit dramatic sensitivity to the EGFR tyrosine kinase inhibitors gefitinib and erlotinib. Ionizing radiation (IR) is frequently used in the treatment of NSCLC, but little is known how lung tumor-acquired EGFR mutations affect responses to IR. Because this is of great clinical importance, we investigated and found that clonogenic survival of mutant EGFR NSCLCs in response to IR was reduced 500- to 1,000-fold compared with wild-type (WT) EGFR NSCLCs. Exogenous expression of either the L858R point mutant or the DeltaE746-E750 deletion mutant form of EGFR in immortalized human bronchial epithelial cells, p53 WT NSCLC (A549), or p53-null NSCLC (NCI-H1299) resulted in dramatically increased sensitivity to IR. We show that the majority of mutant EGFR NSCLCs, including those that contain the secondary gefitinib resistance T790M mutation, exhibit characteristics consistent with a radiosensitive phenotype, which include delayed DNA repair kinetics, defective IR-induced arrest in DNA synthesis or mitosis, and pronounced increases in apoptosis or micronuclei. Thus, understanding how activating mutations in the TKD domain of EGFR contribute to radiosensitivity should provide new insight into effective treatment of NSCLC with radiotherapy and perhaps avoid emergence of single agent drug resistance.     

Gefitinib induces apoptosis in the EGFRL858R non-small-cell lung cancer cell line H3255

Somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) have recently been described in patients with non-small-cell lung cancer (NSCLC) who achieve radiographic regressions to the EGFR inhibitor gefitinib. One of these mutations, L858R (Leu-->Arg), is also found in NSCLC cell line H3255, which is very sensitive to gefitinib treatment. We characterized nine NSCLC cell lines (three isolated from patients with bronchioloalveolar carcinoma and six isolated from patients with adenocarcinoma) for their in vitro sensitivity to gefitinib. Of these, only H3255 (EGFR(L858R)) and H1666 (EGFR(WT)) are sensitive to gefitinib with IC(50) values of 40 nmol/L and 2 micromol/L, respectively. We examined the effects of gefitinib on H3255 and cell lines containing wild-type EGFR that are either sensitive (H1666) or resistant (A549 and H441) to gefitinib exposure in vitro. Gefitinib treatment (1 micromol/L) leads to significant apoptosis accompanied by increased poly(ADP-ribose) polymerase cleavage only in the H3255 cell line, leads to G(1)-S arrest in H1666, and has no effects in the A549 and H441 cell lines. Although EGFR and AKT are constitutively phosphorylated in H3255, H1666, and H441 cell lines, AKT is completely inhibited by gefitinib treatment only in the H3255 cell line. These findings further characterize a mechanism by which gefitinib treatment of NSCLC harboring EGFR(L858R) leads to a dramatic response to gefitinib.     

Vacquinol-1对非小细胞肺癌细胞增殖和凋亡的影响

目的:探讨Vacquinol-1对非小细胞肺癌细胞系A549、NCI-H1299细胞增殖和凋亡的影响及可能机制。方法:以不同浓度的Vacquinol-1作用于A549和NCI-H1299细胞,应用CCK-8法检测其对细胞增殖能力的影响;以半数致死浓度（half maximal inhibitory concentration,IC50）作用于细胞,流式细胞术Annexin V/PI双染色法检测细胞的凋亡情况;Western blotting法检查凋亡相关蛋白Caspase-3、Bcl-2和Bax表达的变化情况。结果:CCK-8结果显示Vacquinol-1能显著抑制A549、NCI-H1299细胞的增殖能力;并且流式细胞术检测结果显示Vacquinol-1能诱导A549、NCI-H1299细胞的凋亡;Western blotting结果显示Vacquinol-1促进A549、NCI-H1299细胞Caspase-3、Bax的表达,抑制Bcl-2的表达。结论:Vacquinol-1能够抑制非小细胞肺癌细胞的增殖,并且通过激活线粒体通路诱导细胞凋亡。     

Gefitinib radiosensitizes non-small cell lung cancer cells by suppressing cellular DNA repair capacity.

PURPOSE: Overexpression of the epidermal growth factor receptor (EGFR) promotes unregulated growth, inhibits apoptosis, and likely contributes to clinical radiation resistance of non-small cell lung cancer (NSCLC). Molecular blockade of EGFR signaling is an attractive therapeutic strategy for enhancing the cytotoxic effects of radiotherapy that is currently under investigation in preclinical and clinical studies. In the present study, we have investigated the mechanism by which gefitinib, a selective EGFR tyrosine kinase inhibitor, restores the radiosensitivity of NSCLC cells. EXPERIMENTAL DESIGN: Two NSCLC cell lines, A549 and H1299, were treated with 1 micromol/L gefitinib for 24 h before irradiation and then tested for clonogenic survival and capacity for repairing DNA double strand breaks (DSB). Four different repair assays were used: host cell reactivation, detection of gamma-H2AX and pNBS1 repair foci using immunofluorescence microscopy, the neutral comet assay, and pulsed-field gel electrophoresis. RESULTS: In clonogenic survival experiments, gefitinib had significant radiosensitizing effects on both cell lines. Results from all four DNA damage repair analyses in cultured A549 and H1299 cells showed that gefitinib had a strong inhibitory effect on the repair of DSBs after ionizing radiation. The presence of DSBs was especially prolonged during the first 2 h of repair compared with controls. Immunoblot analysis of selected repair proteins indicated that pNBS1 activation was prolonged by gefitinib correlating with its effect on pNBS1-labeled repair foci. CONCLUSIONS: Overall, we conclude that gefitinib enhances the radioresponse of NSCLC cells by suppressing cellular DNA repair capacity, thereby prolonging the presence of radiation-induced DSBs.     

Abnormal expression pattern of the ASPP family of proteins in human non-small cell lung cancer and regulatory functions on apoptosis through p53 by iASPP

The p53 protein is one of the best-known tumor suppressors. Recently discovered ASPP1 and ASPP2 are specific activators and iASPP is an inhibitor of p53. In the present study, we found that of 37 NSCLC patients, p53 alterations were detected in 20 tumors (54.1%), the mRNA expression of ASPP1 and ASPP2 was frequently dowregulated in tumor tissues, and this decreased significantly in samples expressing wild-type p53. The expression of ASPP1 and ASPP2 was downregulated and that of iASPP was upregulated in two NSCLC cell lines (the NCI-H157 cell line with altered p53 and the A549 cell line with wild-type p53). The NCI-H157 cell with higher ASPP1 and ASPP2 levels was more sensitive to cisplatin than the A549 cells with lower ASPP1 and ASPP2 levels. Downregulation of iASPP by siRNA stimulated apoptosis through p53 in two NSCLC cell lines. These findings provide new insights into the molecular mechanisms of action of the ASPP family in NSCLC and may have potent therapeutic applications.     

miR-769-5p在非小细胞肺癌中的表达及其对细胞增殖、迁移与侵袭能力的影响

目的 探讨微小RNA-769-5p （miR-769-5p） 在非小细胞肺癌（NSCLC）细胞株中的表达及其对细胞增殖、迁移和侵袭能力的影响。方法 采用实时荧光定量PCR（QPCR）技术检测miR-769-5p 在5种NSCLC细胞（A549、NCI-H1299、NCI-H157、ANIP-973和GLC-82）中的相对表达量,选择相对表达量最低和最高的细胞株分别转染miR-769-5p mimics／miR-769-5p inhibitor,另设miRNA mimics control／inhibitor control对照组;采用MTS 实验、克隆形成实验及Transwell 小室实验检测miR-769-5p对NSCLC 细胞增殖、克隆形成、侵袭和迁移能力的影响。结果 miR-769-5p在A549、NCI-H1299、NCI-H157、ANIP-973 及GLC-82细胞中的相对表达量分别为 0.06、0.40、0.09、1.04和2.31。在miR-769-5p表达水平最低的A549细胞中瞬时转染miR-769-5p mimics,在miR-769-5p表达水平最高的GLC-82细胞中瞬时转染miR-769-5p inhibitor。MTS结果显示,与对照组比较,miR-769-5p mimics 能够抑制A549细胞的增殖 （P＜0.05）,而miR-769-5p inhibitor能够促进GLC-82细胞的增殖 （P＜0.05）。平板克隆实验结果显示,与对照组比较,miR-769-5p mimics 能够抑制A549细胞的平板克隆形成数 （124.7±14.7 vs. 399.4±46.0,P＜0.05）;而miR-769-5p inhibitor能够促进GLC-82细胞的平板克隆形成数 （555.7±29.7 vs. 366.3±28.7,P＜0.05）。Transwell实验结果显示,与对照组迁移和侵袭跨膜细胞数比较,miR-769-5p mimics能够抑制A549细胞的迁移和侵袭 （94.4±18.1 vs. 157.8±22.9,84.4±15.1 vs. 135.6±16.7,P＜0.05）;miR-769-5p inhibitor能够促进GLC-82细胞的迁移和侵袭 （226.7±40.3 vs. 153.3±38.7,196.7±39.1 vs. 138.9±40.4,P＜0.05）。结论 miR-769-5p可以抑制NSCLC细胞的增殖、侵袭和迁移,可能成为NSCLC的潜在靶点。     

人非小细胞肺癌细胞EGFR基因启动子甲基化与吉非替尼敏感性之间的相关性研究

目的 探讨EGFR基因启动子甲基化水平与人非小细胞肺癌（NSCLC）细胞株对吉非替尼敏感性之间的相关性。方法 用不同浓度吉非替尼分别作用于NSCLC细胞株HCC827、H1650、H1975、H358、H1299、A549后,CCK-8法检测细胞增殖抑制率,DNA直接测序法、实时荧光定量PCR法、免疫印迹法和甲基化特异性PCR法分别检测上述NSCLC细胞株EGFR基因突变、EGFR mRNA、EGFR蛋白表达和启动子区甲基化状态。结果 CCK-8法检测结果显示,19外显子缺失突变的HCC827细胞对吉非替尼最敏感,而同为19外显子缺失突变的H1650细胞对吉非替尼不敏感;野生型的H358细胞对吉非替尼中度敏感,其敏感性甚至超过19外显子突变的H1650细胞,而同为EGFR野生型的H1299、A549细胞对吉非替尼敏感性较差。吉非替尼处理72h后,HCC827细胞与H358细胞相比、HCC827细胞和H358细胞与其他4株细胞相比,IC50值均有显著性差异（P＜0.05）。HCC827细胞EGFR启动子为未甲基化状态,其EGFR蛋白和mRNA表达最高;H358细胞为部分甲基化,其EGFR蛋白和mRNA为中等表达;其他4个细胞株均为高甲基化状态,EGFR蛋白和mRNA呈低表达;HCC827细胞的EGFR表达水平较H358细胞高,HCC827和H358细胞的EGFR表达较其他4个细胞株高,差异均有统计学意义（P＜0.05）。结论 EGFR基因启动子区高甲基化可能下调EGFR基因的表达水平,从而降低NSCLC对吉非替尼的敏感性;对该基因的甲基化检测可能对预测吉非替尼治疗NSCLC疗效有一定的临床指导意义。     

p53 Cooperates berberine-induced growth inhibition and apoptosis of non-small cell human lung cancer cells in vitro and tumor xenograft growth in vivo

Berberine has been shown to have anti-carcinogenic effects. Since p53 is the most commonly mutated tumor suppressor gene, and a lack of functional p53 is associated with an increased risk of cancer development, we examined the effects of berberine on p53-positive and p53-deficient non-small cell human lung cancer cells in vitro and in vivo. Treatment of A549, which express wild-type p53, and H1299, which are p53-deficient, human lung cancer cells with berberine resulted in inhibition of cell proliferation and an increase in apoptotic cell death; however, A549 cells were more sensitive to the berberine-induced cytotoxic effects than H1299 cells. Further, the treatment of A549 cells with pifithrin-alpha, a specific inhibitor of p53, or transfection of A549 cells with a p53 antisense oligodeoxynucleotide resulted in a reduction in the berberine-induced inhibition of cell proliferation and apoptosis. The berberine-induced apoptosis of both the A549 and H1299 human lung cancer cells was associated with the disruption of mitochondrial membrane potential, reduction in the levels of Bcl-2, Bcl-xl while increase in Bax, Bak, and activation of caspase-3. Treatment of the cells with pan-caspase inhibitor (z-VAD-fmk) or caspase-3 inhibitor (z-DEVD-fmk) inhibited berberine-induced apoptosis, thus suggesting the role of caspase-3. Further, the administration of berberine by oral gavage inhibited the growth of s.c. A549 and H1299 lung tumor xenografts in athymic nude mice, however, the growth of tumor xenograft of H1299 cells was faster than A549 cells in mice and the chemotherapeutic effect of berberine was more pronounced in the p53-positive-A549 tumor xenograft than p53-deficient-H1299 tumor xenograft.     

Anti-cancer effect of tectochrysin in NSCLC cells through overexpression of death receptor and inactivation of STAT3

Phenolic compounds (flavonoids and phenolic acid derivatives) are the most important pharmacologically active ingredients, and these compounds could inhibit proliferation of human cancer cells by inducing of apoptotic cell death. Here we focused on the anticancer effects of tectochrysin on human non-small-cell lung cancer (NSCLC) cells and its mechanism of action. We analysed the activity of tectochrysin on NSCLC cells (A549 and NCI-H460) by use of Western blot analysis for major apoptotic proteins and death receptor expression. We also used EMSA for effects on STAT3 DNA binding activity. Tectochrysin (0–80 μM) suppressed the growth of A549 and NCI-H460 lung cancer cells by inducing of apoptotic cell death in a concentration dependent manner. Expression of DR3 and Fas as well as DR downstream pro-apoptotic proteins including cleaved caspase-3, cleaved caspase-8, cleaved caspase-9 and Bax were concomitantly increased, but the expression of anti-apoptotic proteins; Bcl-2 was decreased in both cancer cells. In addition, tectochrysin treatment also inhibited phosphorylation of STAT3 in A549 and NCI-H460 cells. However, deletion of DR3 and Fas by small interfering RNA significantly reversed tectochrysin-induced cell growth inhibitory effect as well as down regulation of STAT3 in A549 and NCI-H460 lung cancer cells. Pull down assay and docking model showed interaction of tectochrysin with STAT3. We propose that tectochrysin leads to apoptotic cell death in NSCLC cells through activation of DR3 and Fas expression via inhibition of STAT3 phosphorylation.     

KRAS-mutated non-small cell lung cancer cells are responsive to either co-treatment with erlotinib or gefitinib and histone deacetylase inhibitors or single treatment with lapatinib

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors erlotinib and gefitinib provide significant clinical benefit for non-small cell lung cancer (NSCLC) patients whose tumors bear EGFR mutations/amplifications. However, anti-EGFR therapy is largely ineffective in NSCLC with activating KRAS mutations. In this study, we investigated the treatment efficacy of erlotinib and gefitinib in combination with the histone deacetylase inhibitors (HDACi) vorinostat and sodium butyrate in the KRAS-mutated NSCLC cell line A549. For comparison, we tested the combination of HDACi with the dual tyrosine kinase inhibitor lapatinib. A549 cells proved to be resistant to erlotinib and gefitinib, but could be sensitized by cotreatment with HDACi, as assessed by flow cytometric analyses of cell death and mitochondrial depolarization. In contrast, A549 cells were a priori responsive to lapatinib treatment, but responsiveness to lapatinib could not be enhanced by HDACi cotreatment. These divergent effects of the different combination regimens may be explained by dissimilar types of cell death induced by the treatments: The use of the pan-caspase inhibitor z-VAD-fmk in the cell death and mitochondrial depolarization assays as well as fluorescence microscopy analyses indicated that erlotinib or gefitinib combined with HDACi elicited apoptosis, whereas lapatinib treatment induced a non-apoptotic type of cell death. Our study suggests that both HDACi/EGFR inhibitor-combination treatment and lapatinib-single treatment may be effective options for the therapy of NSCLC with KRAS mutations.     

环状RNA CircHIPK3通过miR-379调控IGF1表达促进非小细胞肺癌细胞系NCI-H1299与NCI-H2170的细胞增殖

背景与目的 已有的研究证明:环状RNA是一类在哺乳动物中普遍存在的具有稳定闭合环状结构的内源性RNA分子.环状RNA circHIPK3(circular RNA HIPK3,circHIPK3)在肝细胞癌(hepatocellular carcino-ma,HCC)中表达水平较高,促进肝癌细胞生长.但是其在非小细胞肺癌(non-small cell lung cancer,NSCLC)中的作用及其调控机制尚无文献报道.本研究拟探讨环状RNA circHIPK3对NSCLC细胞系NCI-H1299和NCI-H2170细胞增殖的影响,并进一步研究其调控的分子机制.方法 Real-time PCR法检测circHIPK3在NSCLC各细胞系中的表达水平.CCK-8实验和克隆形成实验检测过量表达和干扰circHIPK3对细胞增殖的影响.双荧光素酶报告基因实验分别检验miR-379与circHIPK3及miR-379与IGF1 mRNA的结合情况.Western blot和ELISA检测细胞内外的IGF1蛋白表达水平.结果 环状RNA circHIPK3在6株NSCLC细胞株中均有表达,其中H1299表达最低,H2170表达最高,通过转染过表达的circHIPK3可显著促进NCI-H1299细胞增殖,干扰circHIPK3可显著抑制NCI-H2170细胞增殖.miR-379可与circHIPK3及IGF1 mRNA直接结合.过表达circHIPK3导致IGF1表达量上调,干扰circHIPK3能够下调IGF1表达水平,转入miR-379 mimics恢复了circHIPK3稳转细胞株IGF1表达水平的上调及细胞增殖表型.结论 环状RNA circHIPK3在NSCLC细胞系NCI-H1299及NCI-H2170中可通过miR-379调控IGF1表达促进细胞增殖,环状RNA circHIPK3可能成为非小细胞肺癌治疗的新靶点.     

HER2 overexpression increases sensitivity to gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, through inhibition of HER2/HER3 heterodimer formation in lung cancer cells

Gefitinib (Iressa), an epidermal growth factor receptor targeting drug, has been clinically useful for the treatment of patients with non-small cell lung cancer (NSCLC). Gefitinib is currently being applied in clinical studies as either a monotherapy, or as part of a combination therapy against prostate, head and neck, gastric, breast, and colorectal tumors. However, success rates vary between different tumor types, and thus it is important to understand which molecular target(s) are responsible for limiting the therapeutic efficacy of the drug. In this study, we ask whether expression of HER2 affects sensitivity to gefitinib in human lung cancer cells. We established two clones, LK2/HER2-32 and LK2/HER2-57, by transfecting HER2 cDNA into LK2, a NSCLC line with a low expression level of HER2. We observed no mutations in exons 18, 19, and 21 of EGFR gene in LK2, LK2/mock- and two HER2-trasfectants when we observed in-frame deletion mutations (E746-A750) adjacent to K745 in a gefitinib-sensitive NSCLC cell line, PC9. These LK2/HER2-32 and LK2/HER2-57 were much more sensitive to the cytotoxic effects of gefitinib than the parental LK2 lines. Treatment with 0.5 to 1 micromol/L gefitinib specifically blocked Akt activation in both HER2-transfectant lines, but not in the parental LK2 cells. Extracellular signal-regulated kinase-1/2 activation, however, was not blocked by gefitinib up to 10 micromol/L in either the parent or transfectant lines. Gefitinib was also shown to induce cell cycle arrest in the G1-S phase, and an accompanying increase of p27Kip1 was observed. LK2/HER2 transfectants showed constitutive formation of HER2/HER3 heterodimer, which were seen to associate with a regulatory subunit of phosphoinositide-3-kinase, p85alpha, when active. Treatment of LK2/HER2 cells with gefitinib markedly decreased the formation of HER2/HER3 heterodimers, HER3 basal phosphorylation, and the association of p85alpha with HER3. This study is the first to show that under basal growth conditions, HER2 sensitizes low-EGFR NSCLC cell lines to growth inhibition by gefitinib.     

Loss of expression of the differentially expressed in adenocarcinoma of the lung (DAL-1) protein is associated with metastasis of non-small cell lung carcinoma cells

The differentially expressed in adenocarcinoma of the lung-1 (DAL-1) protein is a member of the membrane-associated cytoskeleton protein 4.1 family. This protein was previously found to be downregulated or lost in more than half of primary non-small cell lung cancers (NSCLC). In this study, the relationship between DAL-1 expression and NSCLC metastasis was examined. DAL-1 mRNA and protein levels were measured in NSCLC cell lines and in tumor cells isolated from the pleural fluid of NSCLC patients clinically diagnosed with distant metastases to the bone or brain. The results revealed that DAL-1 expression was observed in two (GLC-82 and NCI-H460) out of seven metastatic NSCLC cell lines examined. DAL-1 expression was not observed in the cells isolated from the pleural fluid in nine out of ten patients. Overexpression of DAL-1 in A549 cells, a cell line lacking endogenous DAL-1, inhibited cell migration and invasion by approximately 38 and 48?%, respectively. In contrast, DAL-1 knockdown in NCI-H460 cells enhanced the migration and invasion potential of this cell line 4.6- and 3-fold, respectively. Furthermore, DAL-1 promoter methylation was observed in six of nine pleural fluid NSCLC cell isolates and in two cell lines (A549 and H1299), as evidenced by a lack of endogenous DAL-1. Demethylation in A549 cells successfully restored DAL-1 mRNA and protein expression levels, resulting in a parallel remarkable inhibition of migration and invasion. These results indicated that DAL-1 was pivotal in triggering NSCLC migration and invasion and that loss of DAL-1 expression was due to the epigenetic methylation.     

Adenovirus-mediated p16INK4a gene expression radiosensitizes non-small cell lung cancer cells in a p53-dependent manner

We examined the influence of adenovirus-mediated wild-type p16INK4a (Ad/p16) expression on the radiation sensitivity of NSCLC cell lines, all of which lacked constitutive p16INK4a but each of which varied in p53 status: A549 (-p16INK4a/ +pRb/wt-p53), H322 (-p16INK4a/ +pRb/mt-p53), and H1299 (-p16INK4a/ +pRb/deleted-p53). The in vitro clonogenic survival results indicate that Ad/p16 enhanced the radiosensitivity of A549 but not H322 or H1299. Further analysis indicated that the apoptosis induced by combination therapy using Ad/p16 plus irradiation was dependent on the endogenous p53 status of the cancer cells. We performed Western blotting to analyse the p53 protein expression of A549 cells treated with either Ad/p16 or Ad/Luc. Endogenous p53 protein levels were higher in A549 cells transfected with Ad/p16 than in those transfected with Ad/Luc. Furthermore, when wt-p53 protein expression was restored in H1299 using Ad/ p53, Ad/p16 stabilized p53 protein expression and radiosensitized the cells. These results suggest that Ad/ p16-induced stabilization of p53 protein may play an important role in Ad/p16 mediated radiosensitization by enhancing or restoring apoptosis properties. Thus, Ad/ p16 plus radiation in combination may be a useful gene therapy strategy for tumors that have wt-p53 but nonfunctional p16INK4a.     

lncRNA HCG18/miR-17-5p/HMGA2 分子轴调控非小细胞肺癌细胞增殖及迁移

[摘要] 目的：探讨lncRNA HCG18/miR-17-5p/HMGA2 分子轴调控非小细胞肺癌（NSCLC）细胞增殖及迁移的分子机制。方法：收集2017 年6 月至2018 年6 月承德市中心医院62 例NSCLC组织及对应的癌旁组织标本,以及NSCLC细胞系A549、NCIH1299、H1650、NCI-H460 和人肺上皮细胞BEAS-B,用qPCR法检测NSCLC组织及细胞系中HCG18、miR-17-5p 及高迁移率族蛋白A2（HMGA2）的表达水平。分别用Si-HCG18、miR-17-5p、miR-17-5p+HCG18 或pcDNA3.1-HMGA2 转染A549 和NCI-H460 细胞,用CCK-8 法、Transwell 实验、Wb检测转染细胞的增殖、迁移、侵袭和HMGA2 及EMT相关蛋白的表达。用双荧光素酶报告基因验证HCG18 对miR-17-5p 或miR-17-5p 对HMGA2 的靶向调控作用。构建敲降HCG18 的A549 细胞小鼠移植瘤模型,观察对移植瘤的影响。结果：lncRNA HCG18 在NSCLC 组织和细胞中均高表达（均P<0.01）,发生淋巴结转移及晚期NSCLC 患者中HCG18 的表达显著提高,且HCG18 高表达的NSCLC患者预后较差、生存率较低（均P<0.01）。转染Si-HCG18 显著抑制NSCLC细胞的增殖、迁移及侵袭能力（均P<0.01）,上调上皮钙黏蛋白的表达（P<0.01）、下调神经钙黏蛋白和波形蛋白的表达（均P<0.01）,小鼠移植瘤体积显著减小（P<0.05）。双荧光素酶报告基因验证了HCG18 与miR-17-5p 靶向结合,以及miR-17-5p 与HMGA2 靶向结合。转染miR-17-5p 后NSCLC 细胞的增殖、迁移及侵袭受到抑制（均P<0.01）,促进上皮钙黏蛋白的表达（P<0.01）、抑制神经钙黏蛋白和波形蛋白的表达（均P<0.01）,而转染miR-17-5p+HCG18 后可抑制miR-17-5p 的作用。结论：HCG18通过调控miR-17-5p/HMGA2 分子轴促进NSCLC细胞的增殖及迁移。     

Epithelial to mesenchymal transition derived from repeated exposure to gefitinib determines the sensitivity to EGFR inhibitors in A549, a non-small cell lung cancer cell line

Epithelial to mesenchymal transition (EMT) has been reported to be related with reduced sensitivity to EGFR tyrosine kinase (EGFR-TK) inhibitors. We performed this study to investigate whether this phenomenon would play a role in acquired resistance to gefitinib. In this study, we established a gefitinib-resistant subline (A549/GR), which was derived from the parental A549 cell line by chronic, repeated exposure to gefitinib. Compared with the A549 cells, the A549/GR cells were approximately 7.7-fold more resistant to gefitinib and they showed the cross-resistance against other EGFR-TK inhibitors, including CL-387,758, erlotinib and ZD6478. Phenotypic changes such as a spindle-cell shape and increased pseudopodia formation suggesting EMT was present in the A549/GR cells. These changes were accompanied by a decrease of E-cadherin and an increase of vimentin, which is a mesenchymal marker. In addition, the ability of invasion and migration was increased in the A549/GR cells. TGF-beta1 treatment for 72 h also induced EMT in the A549 cells and this transition led to resistance to gefitinib. Conversely, this was reversed through the removal of TGF-beta1. In conclusion, induction of EMT may contribute to the decreased efficacy of therapy in primary and acquired resistance to gefitinib.     

Low Expression LncRNA TUBA4B is a Poor Predictor of Prognosis and Regulates Cell Proliferation in Non-Small Cell Lung Cancer

We aimed to unveil the clinical roles and biological function of lncRNA TUBA4B in on-small cell lung cancer (NSCLC). The relative expression level of TUBA4B was estimated by qPCR in 114 pairs of NSCLC and NT samples and the relation of TUBA4B to clinical data of NSCLC patients was analyzed. We found TUBA4B was lower expressed in NSCLC and five cell lines. The lower expression of TUBA4B was remarkably correlated with advanced TNM stage and lymph node metastasis and served as a predictor for overall survival of NSCLC. After overexpression of TUBA4B, cell proliferation ability of A549 and NCI-H1299 remarkably decreased. Our study ascertained low expression TUBA4B in NSCLC tissue, cell lines and is a poor predictor for prognosis and can regulate cell proliferation in NSCLC.     

Sorafenib is efficacious and tolerated in combination with cytotoxic or cytostatic agents in preclinical models of human non-small cell lung carcinoma

Purpose: Sorafenib tosylate (sorafenib, BAY 43-9006, Nexavar®) is a multi-kinase inhibitor that targets tumor cell proliferation and angiogenesis. These studies evaluated the efficacy and tolerability of combinations of sorafenib plus agents used to treat non-small cell lung cancer (NSCLC) using preclinical models of that disease. Methods: Intravenous (iv) vinorelbine and interperitoneal (ip) cisplatin were administered intermittently (q4d × 3) in combination with sorafenib administered orally (po) once daily for 9 days starting on the same day as the standard agent. In studies with sorafenib and gefitinib, both agents were administered po daily for 10 days starting on the same day. Treatment in all studies was initiated against established sc tumors, and each study was conducted in duplicate. Efficacy was assessed as the delay in tumor growth to a specified size (TGD). Results: Vinorelbine (6.7 mg/kg) and sorafenib (40 mg/kg) produced TGDs of 2.4 and 7.8 days, respectively, in the NCI-H460 NSCLC model. Combination therapy produced a 10.0-day TGD with no increase in toxicity. Combination therapy in the NCI-H23 NSCLC model with the highest evaluated dose levels of sorafenib plus cisplatin was well tolerated and produced TGDs equivalent to those produced by cisplatin alone. Lower dose levels of each agent produced approximately additive TGD’s. Combination therapy in the A549 NSCLC model with sorafenib and gefitinib produced TGDs equivalent to that produced by sorafenib alone with no toxicity. Tumor growth in the MDA-MB-231 mammary tumor model, that contains mutations in signal transduction proteins downstream of the EGF receptor (the target of gefitinib) was also inhibited by sorafenib, but not by gefitinib. Conclusion: Concurrent administration of sorafenib and vinorelbine, cisplatin or gefitinib was at least as efficacious as the individual agents alone and was well tolerated. These results support the inclusion of sorafenib in clinical trials in NSCLC employing combinations of both cytotoxic and cytostatic agents.