mir-17-5p、mir-92a、let-7b表达水平与非小细胞肺癌顺铂耐药的关系

目的探讨mir-17-5p、mir-92a、let-7b表达水平与非小细胞肺癌顺铂耐药关系。 方法以人非小细胞肺癌细胞系A549及其耐药株A549/DDP为研究对象,采用RT-PCR法检测mir-17-5p、mir-92a及let-7b在细胞中的表达水平,采用cck8检测其细胞存活情况,采用细胞克隆平台方法,检测转染前后细胞的增殖情况,采用流式细胞仪检测转染前后细胞的凋亡情况。 结果（1） A549/DDP细胞mir-17-5p的表达水平是A549细胞的2.11±0.25倍（P＜0.05）;A549/DDP细胞mir-92a的表达水平是A549细胞的 7.40 ± 1.05 倍（P＜0.05）;而A549/DDP 细胞let-7b 的表达水平是A549 细胞的（26.54 ± 2.90）%（P＜0.05）;（2）A549 转染mir-17-5pmimic,mir-92a mimic 以及let-7b inhibitor 后对顺铂的敏感性下降（P＜0.05）;A549/ddp 转染mir-17-5p inhibitor, mir-92a inhibitor以及let-7b mimic后对顺铂的敏感性增加（P＜0.05）;（3）A549转染mir-17-5p mimic,mir-92a mimic以及let-7b inhibitor 后,细胞形成克隆集落数量数量多于对照组（P＜0.05）;而A549/ddp 转染mir-17-5p inhibitor,mir-92a inhibitor 以及 let-7b mimic 后,细胞形成克隆集落数量数量少于对照组（P＜0.05）;（4）A549 转染mir-17-5p mimic,mir-92a mimic 以及let-7b inhibitor后,细胞凋亡率明显低于对照组（P＜0.05）;而a549/ddp转染mir-17-5p inhibitor,mir-92a inhibitor以及let-7b mimic后, 细胞凋亡率明显高于对照组（P＜0.05）。结论Mir-17-5p、mir-92a表达水平升高,let-7b表达水平下降,可以促进肺癌细胞增殖, 抑制其凋亡以及使肺癌细胞对顺铂敏感性下降。      

miR-802对叉头框转录因子M1抑制A549/DDP细胞顺铂耐药性的靶向调控作用

目的探讨miR-802抑制非小细胞肺癌A549/DDP细胞的顺铂耐药性及其对叉头框转录因子M1(forkhead box protein M1, FoxM1)的靶向调控作用。方法 A549、A549/DDP细胞采用反转录PCR法检测miR-802相对表达量。将A549/DDP细胞分为空白转染组和miR-802过表达组(过表达组),分别转染miR-NC和miR-802类似物(miR-802 mimics),转染24、48、72、96 h后,采用反转录PCR法检测2组细胞miR-802相对表达量,并采用CCK-8法检测2组细胞增殖率;转染48 h后,CCK-8法检测转染后A549/DDP细胞对DDP的敏感性,采用流式细胞仪检测2组细胞凋亡率和细胞周期,采用Western blot法检测转染后A549/DDP细胞内FoxM1蛋白相对表达量。结果 A549/DDP细胞miR-802相对表达量(0.21±0.03)低于A549细胞(0.85±0.12)(P<0.05);转染24、48、72、96 h,过表达组细胞miR-802相对表达量依次增高(P<0.05),且均高于空白转染组(P<0.05);转染48、72、96 h,空白转染组细胞增殖率依次增高(P<0.05),且均高于过表达组(P<0.05);转染48 h,过表达组细胞半数抑制浓度[(35.28±2.17)mg/L]和细胞早期凋亡率[(17.2±1.1)%]均高于空白转染组[(14.22±1.28)mg/L、(9.0±0.8)%](P<0.05),S期和G2/M期细胞比率[(21.30±0.20)%、(8.35±0.33)%]及细胞内FoxM1蛋白相对表达量(0.21±0.04)均低于空白转染组[(27.54±0.52)%、(14.67±0.70)%、0.44±0.06](P<0.05)。结论 miR-802可能通过抑制FoxM1表达而降低非小细胞肺癌A549/DDP细胞的顺铂耐药性。     

MiR-454 promotes the progression of human non-small cell lung cancer and directly targets PTEN

PurposeMicroRNA-454 has been proven dysregulated in some human malignancies and correlated with tumor progression. However, its expression and function in non-small cell lung cancer (NSCLC) is still unclear. Thus, the aim of this study was to explore the effects of miR-454 in NSCLC tumorigenesis and development.MethodsUsing quantitative RT-PCR, we detected miR-454 expression in NSCLC cell lines and primary tumor tissues. The association of miR-454 expression with clinicopathological factors and prognosis was also analyzed. Then, the effects of miR-454 on the biological behavior of NSCLC cells were investigated. At last, the potential regulatory function of miR-454 on PTEN expression was confirmed.ResultsmiR-454 was found to be up-regulated in NSCLC tissues and cell lines. High miR-454 expression was closely correlated with lymph node metastasis, advanced TNM stage, and shorter overall survival. Multivariate regression analysis corroborated that miR-454 overexpression was an independent unfavourable prognostic factor for patients with NSCLC. Down-regulation of miR-454 could significantly reduce NSCLC cell proliferation, enhance cell apoptosis, and impair cell invasion and migration in vitro, while up-regulation of miR-454 showed opposite effects. Further, PTEN was confirmed as a direct target of miR-454 by using Luciferase Reporter Assay.ConclusionsThese findings indicate that miR-454 may act as an oncogene in NSCLC and would serve as a potential therapy target for this disease.     

Increased sensitivity of human lung adenocarcinoma cells to cisplatin associated with downregulated contactin-1

Contactin-1 (CNTN-1), a glycosyl phosphatidylinositol anchor neural cell adhesion molecule (ACAM), is thought to function not only in nervous system development but also in the invasion and metastasis of several tumours. To investigate whether CNTN-1 is involved in multidrug resistance (MDR) in lung adenocarcinoma, CNTN-1 expression was compared between MDR human lung adenocarcinoma A549/cisplatin (A549/DDP) cells and its progenitor A549 cells. The comparison showed that CNTN-1 expression in A549/DDP cells was significantly higher than in A549 cells both at the mRNA level and the protein level. In order to confirm the physiological function of the abnormal expression, lentivirus-mediated short hairpin RNA (shRNA) was used to silence CNTN-1. Cell cytotoxicity assay and cell apoptosis assay revealed that silencing CNTN-1 both in A549 cells and in A549/DDP cells not only rendered cells more sensitive to cisplatin than the negative control, but also increased the cisplatin-induced apoptosis. Metastasis and invasion assays demonstrated that CNTN-1 knockdown reduced metastasis and invasion but did not affect A549 or A549/DDP cell proliferation. To investigate whether the abnormal expression of CNTN-1 is associated with characteristics of patients with non-small cell lung cancer (NSCLC), immunohistochemistry was used to detect CNTN-1 expression in 143 tissue samples from NSCLC patients and the results showed that the degree of CNTN-1 expression positively correlated with lymphatic invasion in patients with lung adenocarcinoma who received adjuvant cisplatin- or carboplatin-based treatment after surgery. Thus, we concluded that CNTN-1 is closely related with MDR of lung adenocarcinoma. Additionally, CNTN-1 is a novel marker to predict chemotherapeutic efficacy of patients with lung adenocarcinoma, especially with regard to cisplatin- or carboplatin-based regimens.     

MiR-1 targets PIK3CA and inhibits tumorigenic properties of A549 cells

MicroRNAs are small endogenous RNAs that play important roles in the pathogenesis of human diseases, including malignancy. MicroRNA-1 (miR-1) is downregulated in non-small cell lung cancer (NSCLC); however, the underlying mechanisms by which it suppresses tumorigenesis in NSCLC are largely unknown. We investigated whether phosphoinositide-3-kinase catalytic subunit alpha (PIK3CA) was a novel target of miR-1 in the NSCLC cell line A549, and the mechanism of miR-1 inhibition of the tumorigenic properties of A549 cells is discussed. The influence of miR-1 on A549 cells was studied by transfection with miR-1 mimics or inhibitor. MiR-1 overexpression led to downregulation of PIK3CA protein, but not mRNA by western blot and quantitative real-time PCR, respectively. The dual-luciferase reporter assay confirmed that miR-1 targeted PIK3CA directly. PIK3CA downregulation by miR-1 mimics led to a significant reduction of phosphorylated Akt and survivin protein, the downstream targets of the PI3 K/Akt pathway. Cell proliferation was studied using a cell counting kit. Migration and invasion were evaluated by Transwell and Matrigel assays, respectively. Cell cycle and apoptosis were detected by flow cytometry. The results were that miR-1 upregulation inhibited A549 cell proliferation, migration, and invasion. These findings indicate that miR-1 may play an important role in the pathogenesis of NSCLC by regulating PIK3CA through the PI3 K/Akt pathway. Increasing miR-1 expression may provide a novel approach for NSCLC treatment.     

微小RNA在叉头转录因子M1激活非小细胞肺癌上皮向间质转化中的作用

目的:探讨微小RNA(microRNA)在叉头转录因子M_1(Fox M_1)激活非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞上皮向间质转化(epithelial-mesenehymal transition,EMT)中的作用。方法:将Fox M_1过表达质粒,Fox M_1-shRNA,miR-539、miR-485-5p模拟物及其抑制物转染至人NSCLC细胞株中,应用Western印迹和real-time PCR检测细胞株中Fox M_1蛋白和mRNA及miR-539、miR-485-5p的表达。同时应用CCK-8和细胞迁移实验观察Fox M_1、miR-539和miR-485-5p对NSCLC细胞的增殖和侵袭功能的影响。应用荧光素酶报告基因实验检测miR-539和miR-485-5p与EMT调控蛋白ZEB_1和Snail_1的关系。结果:Fox M_1过表达下调NSCLC细胞中miR-539、miR-485-5p,转染Fox M_1-shRNA后NSCLC细胞中miR-539、miR-485-5p升高。MiR-539和miR-485-5p抑制Fox M_1对NSCLC细胞增殖和侵袭的促进作用。NSCLC细胞中miR-539对EMT调控蛋白ZEB_1,miR-485-5p对EMT调控蛋白Snail_1的表达有抑制作用。结论:miR-539和miR-485-5p能抑制NSCLC细胞中Fox M_1-EMT通路,从而影响NSCLC细胞的增殖和侵袭,抑制NSCLC的远处转移。     

The Clinical Relevance of the miR-197/CKS1B/STAT3-mediated PD-L1 Network in Chemoresistant Non-small-cell Lung Cancer

Programmed cell death ligand-1 (PD-L1) has recently gained considerable attention for its role in tumor immune escape. Here, we identify a miR-197/CKS1B/STAT3-mediated PD-L1 network in chemoresistant non-small-cell lung cancer (NSCLC), independent of immunoinhibitory signals. miR-197 is downregulated in platinum-resistant NSCLC specimens, resulting in the promotion of chemoresistance, tumorigenicity, and pulmonary metastasis in vitro and in vivo. Mechanistic investigations reveal that a miR-197-mediated CKS1B/STAT3 axis exerts tumor progression regulated by various oncogenic genes (Bcl-2, c-Myc, and cyclin D1), and PD-L1 is a putative biomarker of this axis. Furthermore, we demonstrate that a miR-197 mimic sensitizes PD-L1^high drug-resistant cells to chemotherapy. These results indicate that the biological interaction between PD-L1 and chemoresistance occurs through the microRNA regulatory cascade. More importantly, expression levels of miR-197 are inversely correlated with PD-L1 expression (n = 177; P = 0.026) and are associated with worse overall survival (P = 0.015). Our discoveries suggest that the miR-197/CKS1B/STAT3-mediated network can drive tumor PD-L1 expression as a biomarker of this cascade, and miR-197 replacement therapy may be a potential treatment strategy for chemoresistant NSCLC.     

MiR-95 induces proliferation and chemo- or radioresistance through directly targeting sorting nexin1 (SNX1) in non-small cell lung cancer

MicroRNAs are emerging as a class of small regulatory RNAs whose specific roles and significant functions in the majority of carcinomas have yet to be entirely illustrated. The aim of this study is to explore the effect of miR-95 and determine whether miR-95 could be a potential therapeutic target for human non-small cell lung cancer. First of all, our study showed that miR-95 was highly expressed in both NSCLC cell lines (compared with normal cells) and tumor tissues (compared with corresponding normal tissues), whereas the protein level of SNX1 was downregulated in NSCLC cell lines. Next, we found that ectopic overexpression of miR-95 in A549 or H226 contributed to tumor growth in xenograft mouse models. In addition, the results also indicated that upregulation of miR-95 could significantly enhance the susceptibilities of NSCLC cells to chemo- or radiotherapy. Furthermore, using the luciferase reporter, we demonstrated that SNX1 is a direct target of miR-95. Meanwhile, overexpression of SNX1 could abrogate the growth of NSCLC cells induced by miR-95. Taken together, these results suggest that miR-95 functions as an oncogene role in NSCLC cells by directly targeting SNX1.     

PVT1 induces NSCLC cell migration and invasion by regulating IL-6 via sponging miR-760

Non-small-cell lung carcinoma (NSCLC) accounts for approximately 80% of lung cancers with a high metastatic potential. Elucidating the mechanism of NSCLC metastasis will provide new promising targets for NSCLC therapy and benefit its prognosis. Plasmacytoma variant translocation 1 (PVT1) has been proven to be overexpressed in NSCLC. Although the oncogenic role of PVT1 in NSCLC has been reported, its mechanism remains unclear. Here, we verified that the knockdown of PVT1 inhibited NSCLC cell migration and invasion, and that its inhibitory role on A549 cells and H1299 cells was antagonized by interleukin-6 (IL-6) treatment. The results revealed that PVT1 regulates IL-6 by sponging miR-760 and identified the binding site of miR-760 in the 3′-UTR of IL-6. In conclusion, a new mechanism was revealed, wherein PVT1 regulates NSCLC cell migration and invasion via miR-760/IL-6, suggesting PVT1/miR-760/IL-6 as promising prognostic biomarkers and therapeutic targets for NSCLC metastasis.     

Reversal of galectin-1 gene silencing on resistance to cisplatin in human lung adenocarcinoma A549 cells

This study aims to investigate reversal of Galectin-1 gene silencing on resistance to cisplatin in human lung adenocarcinoma A549 (or A549/DDP) in vivo and in vitro. The stably transfected lentivirus vector was used to silence Galectin-1 in human lung adenocarcinoma cell line A549 and A549/DDP cells and the cell lines were cultured and passaged. RT-PCR and western blot assay were used to test A549, A549/DDP cells, silenced Galectin-1A549 (A549/I) cells, Galectin-1 mRNA and protein expression levels, respectively, in A549/DDP (A549/DDP/I) cells. CCK8 assay was used to measure median inhibitory concentration (IC50) in each group and resistant index of A549/DDP cells and A549/DDP/I cells. Tumor model in nude mice was established by armpit injection of A549, A549/DDP, A549/I, A549/DDP/I cells. Cisplatin was injected intraperitoneally in tumor models and growth of tumor was observed in vivo model. Four weeks later, nude mice were killed and tumor weight and diameter was measured. mRNA and protein expression of Galectin-1 in A549/DDP cells was higher than that in A549 cells. mRNA and protein expression of Galectin-1 in A549/DDP/I cells was lower than that in A549/DDP cells. Moreover, IC50 values ​​and resistance index in A549/DDP cells was higher than that in A549 cells group and IC50 values ​​and resistance index A549/DDP/I cell group were lower than that in A549/DDP cells. Additionally, tumor weight and volume in A549/DDP/I cell group were lower than that in A549/DDP. In conclusion, Galectin-1 gene silencing would improve the sensitivity of A549/DDP cells to cisplatin in vivo and in vitro.     

Ultrasound-targeted microbubble destruction mediated miR-492 inhibitor suppresses the tumorigenesis in non-small cell lung cancer

BackgroundUltrasound-targeted microbubble destruction (UTMD) is a novel adjuvant tumor therapeutic method by enhancing exogenous gene transfection to target tissues. This study aims to investigate the role of microRNA-492 (miR-492) in non-small cell lung cancer (NSCLC) and further analyze the effects of UTMD-mediated miR-492 inhibitor on tumorigenesis.MethodsThe expression of miR-492 was detected by qRT-PCR. Co-transfection of microbubbles and miR-492 inhibitor with Lipofectamine 3000 was performed to achieve UTMD-mediated miR-492 inhibition in NSCLC cells. CCK-8 and Transwell assay were used to determine NSCLC cell proliferation, and the migration and invasion.ResultHigh expression of miR-492 was associated with poor prognosis in NSCLC patients. miR-492 inhibitor suppressed tumor cell proliferation, migration and invasion, and UTMD not only increased the transfection efficiency of miR-492 inhibitor, but also enhance the inhibitory effects on cell biological behaviors.ConclusionThe results showed that the expression level of miR-492 was up-regulated in NSCLC tissue samples and cells. Silencing of miR-492 inhibited NSCLC cell proliferation, migration and invasion, and UTMD-mediated miR-492 inhibitor could promote more significant inhibition, which indicated that UTMD-mediated miR-492 inhibitor might provide a novel strategy for the treatment of NSCLC.

KEY MESSAGES

• miR-492 inhibitor inhibited cell proliferation, migration and invasion.
• UTMD-mediated miR-492 inhibitor can promote more significant inhibition.
• UTMD-mediated miR-492 inhibitor provide a new strategy for NSCLC.

     

m6A甲基转移酶METTL3介导miR-127调控非小细胞肺癌细胞系自噬的机制研究

目的　分析N6 甲基腺苷（m6A）甲基转移酶 3（methyltransferase-like 3, METTL3）和miR-127 在非小细胞肺癌（non small cell lung cancer cells, NSCLC）细胞系中的表达及其相关性,并探究METTL3 介导miR-127 调控非小细胞肺癌自噬的作用机制。方法　采用qRT-PCR 法检测正常肺上皮细胞BEAS-2B 与非小细胞肺癌细胞HCC827,A549 和H460 中METTL3 和miR-127 的表达水平;通过Linked Domics 数据库筛选出肺癌中与miR-127 共表达的基因,并分析METTL3 和miR-127 之间的相关性;选择H460 细胞传代培养至对数生长期后,将浓度接近的细胞随机分为三组,分别转染METTL3-siR,NC-siR 及Control,验证转染后H460 细胞中METTL3 和miR-127 表达;通过吖啶橙染色,Lyso-Tracker Red 染色观察METTL3 对细胞自噬的影响;利用Western blot 检测PTEN,AKT,mTOR,ULK1,Beclin-1等自噬相关蛋白的表达。结果　非小细胞肺癌细胞HCC827,A549,H460 中METTL3 相对表达分别为1.35±0.17,1.54±0.11 和1.78±0.21,明显高于正常肺上皮细胞BEAS-2B 中表达水平（0.91±0.11）,差异有统计学意义(F=34.037,P=0.002)。非小细胞肺癌细胞HCC827,A549,H460 中miR-127 相对表达分别为1.56±0.21,1.85±0.19 和2.11±0.25,较正常肺上皮细胞BEAS-2B 中表达（1.02±0.20）亦显著升高,差异有统计学意义（F=28.152,P=0.005）。肺癌中METTL3 与miR-127 共同表达呈正相关性（r=0.452,P ＜ 0.001）。METTL3-siR 组细胞中METTL3 表达水平（0.61±0.15）较Control 组（1.71±0.28） 和NC-siR 组（1.65±0.19） 显著降低, 差异有统计学意义（F=78.357,P ＜ 0.001）。METTL3-siR 组细胞中miR-127 表达水平（0.48±0.15）较Control 组（2.02±0.33）和NC-siR 组（1.97±0.25）亦显著下降,差异有统计学意义（F=105.216,P ＜ 0.001）;吖啶橙和Lyso-Tracker Red 染色分别观察到METTL3-siR 组细胞酸性自噬小泡增多,自噬溶酶体数量也明显增加。与Control 组和NC-siR 组相比,METTL3-siR 组细胞中PTEN,ULK1,Beclin1 蛋白表达水平显著升高,差异均有统计学意义（F=62.420~175.615,均P<0.001）;p-AKT 和p-mTOR 表达水平显著下降,差异均有统计学意义（F=148.781,87.147,均P<0.001）。结论　METTL3 和miR-127 在非小细胞肺癌细胞系中均呈高表达,且它们之间呈正相关性,沉默METTL3 基因可以抑制miR-127 表达,促进非小细胞肺癌H460 细胞发生自噬,其调控机制可能与PTEN/AKT/mTOR 通路有关。     

Retracted Article: CircRNA PVT1 modulates cell metastasis via the miR-181a-5p/NEK7 axis and cisplatin chemoresistance through miR-181a-5p-mediated autophagy in non-small cell lung cancer

In the initiation and evolution of human cancers, circular RNAs (circRNAs) act as crucial regulators. The aim of this report was to ascertain the functional mechanisms of circRNA plasmacytoma variant translocation 1 (circPVT1) in the metastasis and chemoresistance of non-small cell lung cancer (NSCLC). The levels of circPVT1, microRNA-181a-5p (miR-181a-5p) and non-inherited maternal antigens-related kinase 7 (NEK7) were examined via quantitative real-time polymerase chain reaction (qRT-PCR). The levels of the associated proteins were determined through western blot. Cell counting kit-8 (CCK-8) and flow cytometry were used to assess the half inhibitory concentration (IC₅₀) of cisplatin and cell apoptosis, respectively. Cell invasion was detected by transwell assay. A dual-luciferase reporter assay and RNA immunoprecipitation (RIP) were used to confirm the target relation. The impact of circPVT1 on cisplatin chemoresistance in vivo was investigated using xenograft experiments. CircPVT1 and NEK7 were up-regulated and miR-181a-5p was down-regulated in NSCLC. CircPVT1 knockdown refrained the cisplatin chemoresistance and metastasis of NSCLC cells. MiR-181a-5p was a target of circPVT1 and circPVT1 inhibition alleviated the effects of a miR-181a-5p inhibitor on NSCLC cells. The decrease of circPVT1 accentuated the si-NEK7-inhibited metastasis by the miR-181a-5p/NEK7 axis and relieved the 3-methyladenine (3-MA)-promoted cisplatin chemoresistance by miR-181a-5p-mediated autophagy. Down-regulation of circPVT1 facilitated the cisplatin sensitivity of NSCLC cells in vivo. Due to the modulation of cell metastasis via the miR-181a-5p/NEK7 axis and cisplatin chemoresistance by miR-181a-5p-mediated autophagy in NSCLC, circPVT1 might act as an appreciable therapeutic marker for NSCLC.

In the initiation and evolution of human cancers, circular RNAs (circRNAs) act as crucial regulators.     

破骨细胞外泌体miR-183-5p靶向程序性细胞死亡因子4促进肺腺癌细胞增殖及侵袭

目的 探讨破骨细胞来源外泌体(osteoclast-derived exosomes)中miR-183-5p靶向程序性细胞死亡因子4(programmed cell death 4, PDCD4)对肺腺癌侵袭增殖的影响。方法 利用RAW264.7细胞诱导分化破骨细胞并提取外泌体,透射电镜及粒度仪对其进行鉴定。将外泌体与A549细胞共培养,通过CCK8法检测细胞活性,观察miR-183-5p对A549细胞增殖的作用;检测A549细胞周期分布,观察miR-183-5p对细胞周期的作用;利用Transwell侵袭实验,观察miR-183-5p对A549细胞侵袭能力的作用。Western blotting检测PDCD4、周期蛋白D1(Cyclin D1, CCND1)和周期蛋白依赖性激酶4(cyclin dependent kinase, CDK4)相对表达,观察miR-183-5p靶蛋白表达情况及其对A549细胞侵袭、增殖的影响。结果 外泌体呈边缘透亮清晰的椭圆形囊泡状结构,粒径分布范围30-200nm左右,荧光探针发现外泌体能够较快的被肺腺癌细胞A549摄取,并且共培养后A549细胞中miR-183-5p表达水平明显增高(p<0.01)。miR-183-5p高表达可以明显促进A549细胞的侵袭、细胞增殖和周期(p<0.05)。A549细胞中miR-183-5p过表达后,PDCD4表达降低,同时CCND1、CDK4也高表达(p<0.05)。结论 破骨细胞来源的外泌体与A549细胞共培养可提高细胞中miR-183-5p的表达,miR-183-5p通过靶向抑制PDCD4表达可促进肺腺癌细胞侵袭、增殖和迁移能力。     

miR-1278 sensitizes nasopharyngeal carcinoma cells to cisplatin and suppresses autophagy via targeting ATG2B

Chemoresistance to cisplatin (DDP) has become a dominating obstacle to the successful treatment of nasopharyngeal carcinoma (NPC). Recently, accumulating data support the tenet that microRNAs (miRNAs) function as new crucial regulators of diverse biological processes, including chemoresistance. In this study, the miRNA expression profiles in NPC were first analyzed using miRNA microarray dataset. miR-1278 was identified as the most decreased miRNA in NPC tissues. We then validated that miR-1278 was significantly down-regulated in NPC tissues and cell lines. Moreover, decreased miR-1278 was strongly associated with worse overall survival and poor chemotherapy response. Gain-of-function experiments showed that overexpression of miR-1278 dramatically sensitized NPC cells to DDP and reduced autophagy. Mechanistically, ATG2B was identified as a target gene of miR-1278. More importantly, ATG2B overexpression reversed miR-1278-induced suppression of autophagy and DDP resistance. Taken together, our results suggested that miR-1278 inhibited the DDP resistance of NPC cells and autophagy through targeting ATG2B. miR-1278 might function as a novel therapeutic target in NPC treatment.     

Silencing of X-linked inhibitor of apoptosis decreases resistance to cisplatin and paclitaxel but not gemcitabine in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a highly lethal malignancy that often becomes resistant to chemotherapy. The effect of silencing the X-linked inhibitor of apoptosis gene (XIAP) on resistance to cisplatin, paclitaxel and gemcitabine was studied in the NSCLC cell lines A549 and H460. Transfection of these cells with small interfering RNA (siRNA) for XIAP blocked overexpression of the gene, suppressed cell proliferation, increased apoptosis and increased the cells' sensitivity to cisplatin and paclitaxel by preventing the binding of XIAP to caspase3 and increasing the activity of this enzyme. There was no significant difference in resistance to gemcitabine between XIAP-silenced cells and non-transfected cells. Changes in chemoresistance were independent of the activity of caspase-9. Silencing XIAP with siRNA can decrease chemoresistance in NSCLC and may have a potential role in the treatment of this disease.     

Retracted Article: MiR-148a agomir based targeting of c-Met and Her-3 is able to attenuate EGFR-T790M mutation driven gefitinib and erlotinib resistance in non-small cell lung cancer cells

MiR-148a inhibits NSCLC progression. Whether miR-148a would reduce EGFR tyrosine kinase inhibitor (TKI) resistance of NSCLC cells remains underexplored. In this study, 5 NSCLC patients received surgery and gefitinib treatment but developed pleural metastasis. Patients'' NSCLC adopted EGFR T790M mutation. 5 naïve and 5 gefitinib-resisting NSCLC cell lines were derived from patients primary and metastatic tumor tissues, and the 5 gefitinib-resisting NSCLC cell lines were trained with erlotinib to establish the erlotinib-resisting cell lines. MiR-148a levels in cells were analyzed by qRT-PCR. miR-148a overexpression was mimicked by agomir treatment. NSCLC cell malignancy was evaluated by cell proliferation, apoptosis, colony formation and transwell invasion assays. Protein levels of c-Met, Her-3 and IGF-1R were assessed by western blotting. miRNA-mRNA interaction was investigated by luciferase reporter assay and AGO2-RIP. Transient overexpression of MET, ERBB3 or IGF1R gene was achieved by plasmid transfection. Results showed that the MiR-148a level was decreased with the development of gefitinib and erlotinib resistance and that there was an increase in malignancy in NSCLC cells in vitro. Treatment with miR-148a agomir significantly enhanced the cytotoxicity of gefitinib and erlotinib to naïve, gefitinib-resisting and erlotinib-resisting NSCLC cells in vitro while reducing their protein levels of c-Met, Her-3 and IGF-1R, the mRNAs of which were verified as direct targets of miR-148a in NSCLC cells. Restoring c-Met or Her-3 protein levels partially reduced the gefitinib and erlotinib sensitizing effect of miR-148a agomir treatment on NSCLC cells. We concluded that MiR-148a attenuated gefitinib and erlotinib resistance in non-small cell lung cancer cells with EGFR T790M mutation by targeting c-Met and Her-3 expression.

MiR-148a inhibits NSCLC progression.