The 3p21.3 tumor suppressor RBM5 resensitizes cisplatin-resistant human non-small cell lung cancer cells to cisplatin

Objective: Increasing RBM5 levels inhibit tumor cell growth and promote apoptosis. In this study, we investigated the role of RBM5 in the cisplatin resistance observed in human lung non-small cell lung cancer cells and evaluated the effect of RBM5 modulation on cell growth inhibition and apoptosis induced by cisplatin in the parental non-small cell lung cancer cells A549 and their cisplatin resistant counterparts, A549/DDP cells. Methods: RBM5 mRNA and protein expression in the A549 and A549/DDP cells was analyzed by semi-quantitative RT-PCR and western blot. The A549/DDP cells were then transfected with a pcDNA3-RBM5 plasmid, and an RBM5-specific siRNA was transfected into A549 cells, prior to treatment with cisplatin. Semi-quantitative RT-PCR and western blot analyses were performed to confirm the expression of RBM5 mRNA or protein, and knockdown of RBM5 mRNA or protein, respectively. MTT assays were used to evaluate chemosensitivity to cisplatin. Apoptosis was assessed by DAPI nuclear staining and flow cytometric analysis with an Annexin-V-FITC apoptosis kit. Cytosolic cytochrome c, cleaved caspase-3 and cleaved caspase-9 were detected by western blot. Results: The expression of RBM5 mRNA and protein was significantly reduced in the A549/DDP cells compared with the A549 cells. Exogenous expression of RBM5 by the pcDNA3-RBM5 resensitized the response of A549/DDP to cisplatin, resulting in a significant increase in tumor-suppressing activity induced by cisplatin. In contrast, downregulation of RBM5 with siRNA in the A549 cells inhibited cisplatin-induced apoptosis. We also found that the RBM5-enhanced chemosensitivity was associated with the release of cytochrome c into the cytosol, activation of caspase-9 and the downstream marker caspase-3. Conclusion: Our results demonstrate that RBM5 may serve as a biomarker with the ability to predict a response to cisplatin. It may also act as a prognostic indicator in lung cancer patients. Our findings suggest that there may be clinical utility for ectopic RBM5 such as enhancing and resensitizing nonresponders to cisplatin.     

5-Hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone,a polymethoxyflavone,exerts antitumor effect on PI3K/Akt signaling pathway in human gastric cancer cell BGC-7901

5-Hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone (5HHMF), a polymethoxyflavone (PMF) mainly found in citrus plants, exhibits excellent physiological functions. In this study, we aimed to investigate the anticancer activity of 5HHMF against human gastric cancer cell BGC-7901 both in vitro and in vivo and illustrate the potential mechanisms. The proliferation of BGC-7901 cells was assessed by MTT assay. Reactive oxygen species (ROS) level was determined by ELISA kit. The protein expression was determined by western blot analysis. Antitumor activity of 5HHMF in vivo was evaluated in BALB/c nude mice. The results showed that treatment with 5HHMF significantly suppressed BGC-7901 cells proliferation, increased ROS generation, and upregulated cytochrome c release from the mitochondria to the cytosol. Western blot analysis demonstrated that 5HHMF significantly downregulated the expression of procaspase-3, procaspase-9, and PARP and upregulated cleaved caspase-3, cleaved caspase-9, cleaved PARP, and Bax/Bcl-2 ratio. Meanwhile, 5HHMF treatment markedly decreased the expression of PI3K and p-Akt. In addition, 5HHMF effectively inhibited tumor growth in xenograft models in BALB/c nude mice without major side action. In summary, 5HHMF-induced apoptosis via targeting PI3K/Akt, indicating 5HHMF is a potential antitumor agent for gastric cancer.     

5-烯丙基-7-二氟亚甲基白杨素对人肺癌A549细胞裸鼠移植瘤生长的影响

目的研究5-烯丙基-7-二氟亚甲基白杨素（ADFMChR）对人肺癌A549细胞裸鼠移植瘤生长的影响。方法建立人肺癌A549细胞裸鼠移植瘤模型,测定荷人肺癌裸鼠移植瘤的大小和重量,应用免疫组化SP法检测移植瘤组织中PCNA、VEGF、CD31的表达。结果ADFMChR对肺癌移植瘤生长有显著抑制作用（P〈0.01）,5.0、10.0、20.0 mg/（kg.bw）的ADFMChR对移植瘤的瘤重抑制率分别为42.98%,82.31%和89.91%。免疫组化检测结果表明：ADFMChR具有抑制肺腺癌裸鼠移植瘤细胞PCNA、VEGF及CD31蛋白表达作用。结论ADFMChR抑制肺腺癌裸鼠移植瘤的生长作用与其抑制移植瘤细胞PCNA、VEGF以及CD31的蛋白表达相关。     

过表达Snail增强肺癌细胞A549的体外侵袭能力

用锌指转录因子Snail诱导肺癌细胞A549发生上皮细胞-间质转化(epithelial-mesenchymal transition,EMT),检测肺癌发生EMT后细胞侵袭能力的变化,为临床筛选分子靶向药物提供依据.构建pcDNA3.1-snail载体,用pcDNA3.1-snail及空pcDNA3.1载体转染肺癌A549细胞后,进行G418筛选;光镜观察培养后细胞形态学的改变、免疫细胞化学与免疫荧光检测细胞表达E-钙黏着蛋白(E-cadherin)、波形蛋白(vimentin)的改变,Western印迹检测细胞中E-钙黏着蛋白和波形蛋白的改变,Transwell侵袭小室法进行细胞体外侵袭能力检测.采用pcDNA3.1-snail转染细胞后,A549细胞变得细长,细胞融合度降低.免疫细胞化学、免疫荧光、Western印迹结果显示,E-钙黏着蛋白表达降低,波形蛋白表达升高;transwell侵袭小室法结果显示,过表达Snail的A549细胞穿透matrigel胶的细胞数明显增多.结果提示,Snail能有效诱导肺癌发生EMT,并且能增强肺癌的体外侵袭能力.     

Swainsonine activates mitochondria-mediated apoptotic pathway in human lung cancer A549 cells and retards the growth of lung cancer xenografts

Swainsonine (1, 2, 8-trihyroxyindolizidine, SW), a natural alkaloid, has been reported to exhibit anti-cancer activity on several mouse models of human cancer and human cancers in vivo. However, the mechanisms of SW-mediated tumor regression are not clear. In this study, we investigated the effects of SW on several human lung cancer cell lines in vitro. The results showed that SW significantly inhibited these cells growth through induction of apoptosis in different extent in vitro. Further studies showed that SW treatment up-regulated Bax, down-regulated Bcl-2 expression, promoted Bax translocation to mitochondria, activated mitochondria-mediated apoptotic pathway, which in turn caused the release of cytochrome c, the activation of caspase-9 and caspase-3, and the cleavage of poly (ADP-ribose) polymerase (PARP), resulting in A549 cell apoptosis. However, the expression of Fas, Fas ligand (FasL) or caspase-8 activity did not appear significant changes in the process of SW-induced apoptosis. Moreover, SW treatment inhibited Bcl-2 expression, promoted Bax translocation, cytochrome c release and caspase-3 activity in xenograft tumor cells, resulting in a significant decrease of tumor volume and tumor weight in the SW-treated xenograft mice groups in comparison to the control group. Taken together, this study demonstrated for the first time that SW inhibited A549 cancer cells growth through a mitochondria-mediated, caspase-dependent apoptotic pathway in vitro and in vivo.     

稳定表达外源性p16基因肺癌A549细胞株的建立及鉴定

为构建稳定表达外源性抑癌基因p16的肺癌A549细胞株,用脂质体介导的基因转染方法,借助真核质粒表达载体（pcDNA3)。将抑癌基因p16转移入此基因缺失的人肺癌细胞株A549细胞中,经G418筛选,获得稳定表达的细胞克隆,用逆转录聚合酶链反应（RT-PCR）及免疫组织化学鉴定p16基因的表达,同时对克隆细胞分泌蛋白进行活性检测。结果显示转染p16基因的A549细胞中可以检测到p16mRNA及蛋白的表达,说明建立的p16真核表达载体能在肺肿瘤细胞中分泌表达蛋白,表达P16抑癌蛋白的A549细胞株的建立有助于研究抑癌基因p16在肺癌发生中的作用。     

CyclinD1反义核酸诱导肺腺癌细胞A549的凋亡

为了探讨CyclinD1反义核酸在肺癌基因治疗中的作用,本研究构建了含有CyclinD1反义核酸的表达载体(命名为:pcDNA3.1-CyclinD1),并将该载体转染肺腺癌细胞A549,进行G418筛选后,获得稳定表达CyclinD1反义核酸的A549细胞(命名为:anti-CyclinD1-A549)。通过MTT法检测细胞增殖,流式细胞术检测细胞的凋亡情况,结果显示稳定转染CyclinD1反义核酸后,A549细胞增殖显著被抑制,细胞凋亡增加。为探讨CyclinD1反义核酸诱导细胞凋亡的机理,应用Westernblot的方法检测了细胞内视网膜母细胞瘤蛋白质(retinoblastoma protein,pRb)、adenovirus E2 factor-1(E2F-1)、血管内皮生长因子(vascular endothelial growth factor,VEGF)、基质金属蛋白酶(matrix metalloproteinase,MMP)-2和MMP-9的表达,其结果显示,稳定转染CyclinD1反义核酸后,A549细胞内pRb、E2F-1、VEGF、MMP-2和MMP-9蛋白表达均显著降低。以上结果表...     

Grape proanthocyanidins induce apoptosis by loss of mitochondrial membrane potential of human non-small cell lung cancer cells in vitro and in vivo

Lung cancer remains the leading cause of cancer-related deaths worldwide, and non-small cell lung cancer (NSCLC) represents approximately 80% of total lung cancer cases. The use of non-toxic dietary phytochemicals can be considered as a chemotherapeutic strategy for the management of the NSCLC. Here, we report that grape seed proanthocyanidins (GSPs) induce apoptosis of NSCLC cells, A549 and H1299, in vitro which is mediated through increased expression of pro-apoptotic protein Bax, decreased expression of anti-apoptotic proteins Bcl2 and Bcl-xl, disruption of mitochondrial membrane potential, and activation of caspases 9, 3 and poly (ADP-ribose) polymerase (PARP). Pre-treatment of A549 and H1299 cells with the caspase-3 inhibitor (z-DEVD-fmk) significantly blocked the GSPs-induced apoptosis of these cells confirmed that GSPs-induced apoptosis is mediated through activation of caspases-3. Treatments of A549 and H1299 cells with GSPs resulted in an increase in G1 arrest. G0/G1 phase of the cell cycle is known to be controlled by cyclin dependent kinases (Cdk), cyclin-dependent kinase inhibitors (Cdki) and cyclins. Our western blot analyses showed that GSPs-induced G1 cell cycle arrest was mediated through the increased expression of Cdki proteins (Cip1/p21 and Kip1/p27), and a simultaneous decrease in the levels of Cdk2, Cdk4, Cdk6 and cyclins. Further, administration of 50, 100 or 200 mg GSPs/kg body weight of mice by oral gavage (5 d/week) markedly inhibited the growth of s.c. A549 and H1299 lung tumor xenografts in athymic nude mice, which was associated with the induction of apoptotic cell death, increased expression of Bax, reduced expression of anti-apoptotic proteins and activation of caspase-3 in tumor xenograft cells. Based on the data obtained in animal study, human equivalent dose of GSPs was calculated, which seems affordable and attainable. Together, these results suggest that GSPs may represent a potential therapeutic agent for the non-small cell lung cancer.     

A novel bioluminescence orthotopic mouse model for advanced lung cancer

Lung cancer is the leading cause of cancer-related death in the United States despite recent advances in our understanding of this challenging disease. An animal model for high-throughput screening of therapeutic agents for advanced lung cancer could help promote the development of more successful treatment interventions. To develop our orthotopic lung cancer model, luciferase-expressing A549 cancer cells were injected into the mediastinum of athymic nude mice. To determine whether the model would allow easy monitoring of response to therapeutic interventions, tumors were treated with 30 mg/kg Paclitaxel or were irradiated with 5 fractions of 2 Gy, and tumor burden was monitored using bioluminescence imaging. Evidence of radiation-induced lung injury was assessed using immunohistochemical staining for phospho-Smad2/3 and cleaved caspase-3. We found that tumor implantation recapitulated advanced human lung cancer as evidenced by tumor establishment and proliferation within the mediastinum. The tumor responded to Paclitaxel or radiation as shown by decreased tumor bioluminescence and improved overall survival. Immunohistochemistry revealed increased phospho-Smad2/3 and cleaved caspase-3 in irradiated lungs, consistent with radiation-induced lung injury. This orthotopic lung cancer model may help provide a method to assess therapeutic interventions in a preclinical setting that recapitulates locally advanced lung cancer.     

The RNA recognition motif domains of RBM5 are required for RNA binding and cancer cell proliferation inhibition

RBM5 is a known putative tumor suppressor gene that has been shown to function in cell growth inhibition by modulating apoptosis. RBM5 also plays a critical role in alternative splicing as an RNA binding protein. However, it is still unclear which domains of RBM5 are required for RNA binding and related functional activities. We hypothesized the two putative RNA recognition motif (RRM) domains of RBM5 spanning from amino acids 98–178 and 231–315 are essential for RBM5-mediated cell growth inhibition, apoptosis regulation, and RNA binding. To investigate this hypothesis, we evaluated the activities of the wide-type and mutant RBM5 gene transfer in low-RBM5 expressing A549 cells. We found that, unlike wild-type RBM5 (RBM5-wt), a RBM5 mutant lacking the two RRM domains (RBM5-ΔRRM), is unable to bind RNA, has compromised caspase-2 alternative splicing activity, lacks cell proliferation inhibition and apoptosis induction function in A549 cells. These data provide direct evidence that the two RRM domains of RBM5 are required for RNA binding and the RNA binding activity of RBM5 contributes to its function on apoptosis induction and cell growth inhibition.     

AIMP3 inhibits cell growth and metastasis of lung adenocarcinoma through activating a miR-96-5p-AIMP3-p53 axis

Aminoacyl-tRNA synthetase-interacting multifunctional protein-3 (AIMP3) is a tumour suppressor, however, the roles of AIMP3 in non-small cell lung cancer (NSCLC) are not explored yet. Here, we reported that AIMP3 significantly inhibited the cell growth and metastasis of NSCLC (lung adenocarcinoma) in vitro and in vivo. We have firstly identified that AIMP3 was down-regulated in human NSCLC tissues compared with adjacent normal lung tissues using immunohistochemistry and western blot assays. Overexpression of AIMP3 markedly suppressed the proliferation and migration of cancer cells in a p53-dependent manner. Furthermore, we observed that AIMP3 significantly suppressed tumour growth and metastasis of A549 cells in xenograft nude mice. Mechanically, we identified that AIMP3 was a direct target of miR-96-5p, and we also observed that there was a negative correlation between AIMP3 and miR-96-5p expression in paired NSCLC clinic samples. Ectopic miR-96-5p expression promoted the proliferation and migration of cancer cells in vitro and tumour growth and metastasis in vivo which partially depended on AIMP3. Taken together, our results demonstrated that the axis of miR-96-5p-AIMP3-p53 played an important role in lung adenocarcinoma, which may provide a new strategy for the diagnosis and treatment of NSCLC.     

Action of solamargine on TNFs and cisplatin-resistant human lung cancer cells

A loss of TNF receptors expression has been found in advanced lung cancers, and human A549 lung adenocarcinoma cells are resistant to the cytotoxic effects of TNF-alpha and cisplatin. Here, the mechanisms of the drug resistance of A549 were extensively studied by gene modulation of the cells by solamargine (SM) which was isolated from Solanum incanum herb. SM induced morphological changes of chromatin condensation, DNA fragmentation, and sub-G(1) peak in a DNA histogram of A549 cells, indicating cell death by apoptosis. SM elevated the expressions of TNF-R1 and -R2 and overcame the resistance of A549 cells to TNF-alpha and -beta. The recruitment of TRADD, FADD, and activation of caspase-8 and -3 in SM-treated A549 cells evidenced the activation of TNFRs signal transduction. In addition, release of cytochrome c from mitochondria, down-expression of Bcl-2 and Bcl-x(L), up-regulation of Bax, and caspase-9 activities were observed in SM-treated A549 cells. Combinational treatment of SM and cisplatin synergistically enhanced caspase-8, -9, and -3 activities in A549 cells. Thus, SM sensitizes A549 cells through TNFRs and mitochondria-mediated pathways and may have anticancer potential against TNFs- and cisplatin-resistance lung cancer cells.     

Smac调控Caspase-3对耐药肺腺癌细胞株生物活性及相关信号的研究

摘要 目的：探讨Smac基因调控Caspase-3表达对紫杉醇耐药肺腺癌细胞株生物活性及经典凋亡信号通路的作用机制。方法：取构建好的耐药A549细胞,将其分为A549细胞（LC）组、A549细胞+Smac-NC（SN）组、A549细胞+Smac抑制剂（SI）组、A549细胞+Smac激动剂（SM）组、A549细胞+Caspase-3-NC（CN）组、A549细胞+Caspase-3抑制剂（CI）组、A549细胞+Caspase-3激动剂（CM）组、A549细胞+Smac激动剂+Caspase-3激动剂（MM）组;Real-time PCR法检测正常肺上皮细胞及4种肺腺癌细胞系中Smac、Caspase-3表达水平,将阴性对照、Smac、Caspase-3类似物转染至紫杉醇耐药肺腺癌细胞株,MTT法检测细胞增殖,流式细胞仪检测细胞凋亡,免疫印迹法检测经典凋亡信号通路表达,并分析Smac与Caspase-3的相关性。结果：肺腺癌细胞系中的Smac、Caspase-3 mRNA表达量显著低于正常肺上皮细胞系BEAS-2B（P＜0.05）,其中A549的Smac、Caspase-3 mRNA值最小（P＜0.05）,因此选取其作为此次实验细胞;LC组与SN组相比,细胞增殖率、凋亡率及Caspase-3、Bcl-2、Bax、Cyto-C蛋白表达基本无差异（P＞0.05）,与SN组相比,SI组细胞凋亡率及Caspase-3、Bax、Cyto-C蛋白表达明显降低（P＜0.05）,增殖率、Bcl-2表达明显升高（P＜0.05）,与SI组相比,SM组细胞凋亡率及Caspase-3、Bax、Cyto-C蛋白表达明显升高（P＜0.05）,增殖率、Bcl-2表达明显降低（P＜0.05）;LC组与CN组相比,细胞增殖率、凋亡率及Caspase-3、Bcl-2、Bax、Cyto-C蛋白表达基本无差异（P＞0.05）,与CN组相比,CI组细胞凋亡率及Caspase-3、Bax、Cyto-C蛋白表达明显降低（P＜0.05）,增殖率、Bcl-2表达明显升高（P＜0.05）,与CI组相比,CM组细胞凋亡率及Caspase-3、Bax、Cyto-C蛋白表达明显升高（P＜0.05）,增殖率、Bcl-2表达明显降低（P＜0.05）;SM组与CM组相比,细胞增殖率、凋亡率及Caspase-3、Bcl-2、Bax、Cyto-C蛋白表达基本无差异（P＞0.05）,与CM组相比,MM组细胞凋亡率及Caspase-3、Bax、Cyto-C蛋白表达明显升高（P＜0.05）,增殖率、Bcl-2表达明显降低（P＜0.05）;Smac与Caspase-3呈现正相关（r=0.470,P=0.002）,组间具有显著差异。结论：Smac基因可显著改善紫杉醇耐药肺腺癌细胞株细胞生物活性,并激活经典凋亡信号通路,其作用机制可能与调控Caspase-3表达有关。     

Diallyl trisulfide induces apoptosis and inhibits proliferation of A549 cells in vitro and in vivo

Lung cancer is the leading cause of cancer-related mortality all over the world. In recent years, pulmonary adenocarcinoma has surpassed squamous cell carcinoma in frequency and is the predominant form of lung cancer in many countries. Epidemiological investigations have shown an inverse relationship between garlic (Allium sativum) consumption and death rate from many cancers. Diallyl trisulfide (DATS) is one of the garlic-derived compounds (also known as: organosulfer compounds, OSC). DATS can induce apoptosis and inhibit the growth of many cancer cell lines. Our study demonstrated that the apoptotic incidents induced by DATS were a mitochondria-dependent caspase cascade through a significant decrease of the anti-apoptotic Bcl-2 that resulted in up-regulation of the ratio of Bax/Bcl-2 and the activity of caspase-3, -8, and -9. Eventually, DATS induced the apoptosis and inhibited the proliferation in a concentration- and time-dependent manner. Furthermore, by establishing an animal model of female BALB/c nude mice with A549 xenografts, we found that oral gavage of DATS significantly retarded growth of A549 xenografts in nude mice without causing weight loss or any other side effects compared with the control group. All the evidence both in vitro and in vivo suggested that DATS could be an ideal anti-cancer drug.     

Suppression of type 1 Insulin-like growth factor receptor expression by small interfering RNA inhibits A549 human lung cancer cell invasion in vitro and metastasis in xenograft nude mice

Cancer invasion and metastasis, involving a variety of pathological processes andcytophysiological changes,contribute to the high mortality of lung cancer.The type 1 insulin-like growthfactor receptor (IGF-1R),associated with cancer progression and invasion,is a potential anti-invasion andanti-metastasis target in lung cancer.To inhibit the invasive properties of lung cancer cells,we successfullydown-regulated IGF-1R gene expression in A549 human lung cancer cells by small interfering RNA (siRNA)technology,and evaluated its effects on invasion-related gene expression,tumor cell in vitro invasion,andmetastasis in xenograft nude mice.A549 cells transfected with a plasmid expressing hairpin siRNA forIGF-1R showed a significantly decreased IGF-1R expression at the mRNA level as well as the proteinlevel.In biological assays,transfected A549 cells showed a significant reduction of cell-matrix adhesion,migration and invasion.Consistent with these results,we found that down-regulation of IGR-1Rconcomitantly accompanied by a large reduction in invasion-related gene expressions,including MMP-2,MMP-9,u-PA,and IGF-1R specific downstream p-Akt.Direct tail vein injections of plasmid expressinghairpin siRNA for IGF- 1R significantly inhibited the formation of lung metastases in nude mice.Our resultsshowed the therapeutic potential of siRNA as a method for gene therapy in inhibiting lung cancer invasionand metastasis.     

Combination of Quercetin and 2-Methoxyestradiol Enhances Inhibition of Human Prostate Cancer LNCaP and PC-3 Cells Xenograft Tumor Growth

Quercetin and 2-Methoxyestradiol (2-ME) are promising anti-cancer substances. Our previous in vitro study showed that quercetin synergized with 2-Methoxyestradiol exhibiting increased antiproliferative and proapoptotic activity in both androgen-dependent LNCaP and androgen-independent PC-3 human prostate cancer cell lines. In the present study, we determined whether their combination could inhibit LNCaP and PC-3 xenograft tumor growth in vivo and explored the underlying mechanism. Human prostate cancer LNCaP and PC-3 cells were inoculated subcutaneously in male BALB/c nude mice. When xenograft tumors reached about 100 mm³, mice were randomly allocated to vehicle control, quercetin or 2-Methoxyestradiol singly treated and combination treatment groups. After therapeutic intervention for 4 weeks, combination treatment of quercetin and 2-ME i) significantly inhibited prostate cancer xenograft tumor growth by 46.8% for LNCaP and 51.3% for PC-3 as compared to vehicle control group, more effective than quercetin (28.4% for LNCaP, 24.8% for PC3) or 2-ME (32.1% for LNCaP, 28.9% for PC3) alone; ii) was well tolerated by BALB/c mice and no obvious toxic reactions were observed; iii) led to higher Bax/Bcl-2 ratio, cleaved caspase-3 protein expression and apoptosis rate; and iv) resulted in lower phosphorylated AKT (pAKT) protein level, vascular endothelial growth factor protein and mRNA expression, microvascular density and proliferation rate than single drug treatment. These effects were more remarkable compared to vehicle group. Therefore, combination of quercetin and 2-ME can serve as a novel clinical treatment regimen owning the potential of enhancing antitumor effect on prostate cancer in vivo and lessening the dose and side effects of either quercetin or 2-ME alone. These in vivo results will lay a further solid basis for subsequent researches on this novel therapeutic regimen in human prostate cancer.     

Putative tumor suppressor Lats2 induces apoptosis through downregulation of Bcl-2 and Bcl-x(L)

Lats2, also known as Kpm, is the second mammalian member of the novel Lats tumor suppressor gene family. Recent studies have demonstrated that Lats2 negatively regulates the cell cycle by controlling G1/S and/or G2/M transition. To further understand the role of Lats2 in the control of human cancer development, we have expressed the protein in human lung cancer cells by transduction of a replication-deficient adenovirus expressing human Lats2 (Ad-Lats2). Using a variety of techniques, including Annexin V uptake, cleavage of PARP, and DNA laddering, we have demonstrated that the ectopic expression of human Lats2 induced apoptosis in two lung cancer cell lines, A549 and H1299. Caspases-3, 7, 8, and 9 were processed in the Ad-Lats2-transduced cells; however, it was active caspase-9, not caspase-8, that initiated the caspase cascade. Inhibitors specific to caspase-3 and 9 delayed the onset of Lats2-mediated apoptosis. Western blot analysis revealed that anti-apoptotic proteins, BCL-2 and BCL-x(L), but not the pro-apoptotic protein, BAX, were downregulated in Ad-Lats2-transduced human lung cancer cells. Overexpression of either Bcl-2 or Bcl-x(L) in these cells lead to the suppression of Lats2-mediated caspase cleavage and apoptosis. These results show that Lats2 induces apoptosis through downregulating anti-apoptotic proteins, BCL-2 and BCL-x(L), in human lung cancer cells.     

miR-126增加非小细胞肺癌细胞A549对顺铂的敏感性

miR-126在多种恶性肿瘤中存在表达下调并显示抑癌基因的功能,然而其在肿瘤敏感性中的作用仍不明确.为了探讨miR-126在非小细胞肺癌细胞A549对顺式铂氨(cis-diammine dichloroplatoum, cisplatin, CDDP)敏感性中的作用及可能机制,本研究用MTS法检测非小细胞肺癌细胞A549及其衍生的CDDP耐受细胞A549/DDP对CDDP的敏感性.结果表明,A549/DDP细胞对CDDP的耐受性是A549细胞的4.05倍(P=0.0078)|用qRT-PCR检测发现,相比于A549细胞,A549/DDP细胞中miR-126的表达下调了8.45倍(P=0.0063),而survivin和Bcl-2的表达明显上调|通过MTS、qRT-PCR及Western印迹实验发现,miR-126 mimics使A549/DDP细胞中miR-126的表达上调了12.63倍(P=0.0013),并明显增加A549/DDP细胞对CDDP的敏感性及下调survivin和Bcl-2的表达;相反,miR-126 inhibitor能明显增加A549细胞对CDDP的耐受性及增加survivin和Bcl-2的表达.本研究结果提示,miR-126在非小细胞肺癌CDDP耐受细胞中的表达下调,上调miR-126的表达能增加耐药细胞对CDDP的敏感性. miR-126是逆转肺癌CDDP耐受的可能潜在靶标.     

lncRNA MAGI2-AS3下调miR-31-5p抑制肺腺癌细胞的增殖、迁移、侵袭并促进凋亡

目的研究lncRNA MAGI2-AS3对肺癌A549细胞增殖、迁移、侵袭和凋亡的影响和潜在的分子机制。方法根据转染载体不同将A549细胞分为pcDNA3.1组(转染pcDNA3.1)、pcDNA3.1-MAGI2-AS3组(转染pcDNA3.1-MAGI2-AS3)、anti-miR-NC组(转染anti-miR-NC)、anti-miR-31-5p组(转染anti-miR-31-5p)、pcDNA3.1-MAGI2-AS3+miR-NC组(共转染pcDNA3.1-MAGI2-AS3和miR-NC)、pcDNA3.1-MAGI2-AS3+miR-31-5p组(共转染pcDNA3.1-MAGI2-AS3和miR-31-5p mimics)。实时荧光定量PCR(qRT-PCR)检测miR-31-5p和MAGI2-AS3 RNA的表达,四氮唑蓝(MTT)法测定A549细胞增殖活性,Transwell实验检测细胞迁移和侵袭能力,双荧光素酶报告系统验证MAGI2-AS3与miR-31-5p的调控关系,流式细胞术检测细胞凋亡与周期。两组间比较采用独立样本t检验进行分析;多组间比较采用单因素方差分析,组内多重比较采用SNK-q检验。结果与人正常肺细胞HBE相比,肺癌细胞A549中的MAGI2-AS3表达量(0.48±0.03比1.29±0.06)降低,miR-31-5p表达量(1.01±0.05比0.25±0.02)升高;与pcDNA3.1组比较,pcDNA3.1-MAGI2-AS3组A549细胞活力(0.48±0.04比0.77±0.06)、迁移[(81.33±2.87)个比(124.33±3.09)个]和侵袭[(32.00±2.83)个比(53.00±3.27)个]细胞数、S期细胞所占比例(23.01﹪±1.00﹪比32.95﹪±1.06﹪)均降低,凋亡率(19.95﹪±1.25﹪比7.23﹪±0.51﹪)、G0-G1期细胞所占比例(43.58﹪±2.15﹪比33.56﹪±1.23﹪)均升高;与anti-miR-NC组比较,anti-miR-31-5p组A549细胞活力(0.53±0.04比0.78±0.06)、迁移[(76.00±3.74)个比(108.33±2.87)个]和侵袭[(30.00±1.63)个比(42.33±2.05)个]细胞数、S期细胞所占比例(24.43﹪±1.13﹪比32.91﹪±1.08﹪)降低,凋亡率(18.21﹪±1.24﹪比7.29﹪±0.51﹪)、G0-G1期细胞所占比例(41.56﹪±2.19﹪比33.53﹪±1.27﹪)升高,差异有统计学意义(P均<0.05);双荧光素酶报告系统结果显示,MAGI2-AS3靶向负调控miR-31-5p的表达。与pcDNA3.1-MAGI2-AS3+miR-NC组比较,pcDNA3.1-MAGI2-AS3+miR-31-5p组A549细胞活力(0.68±0.06比0.50±0.04)、迁移[(91.00±1.63)个比(52.67±2.62)个]和侵袭[(62.67±2.49)个比(31.67±4.03个)]细胞数升高,凋亡率(10.59﹪±1.0﹪比21.11﹪±1.14﹪)降低,差异有统计学意义(P均<0.05)。结论lncRNA MAGI2-AS3通过靶向miR-31-5p抑制A549细胞的增殖、迁移和侵袭,促进细胞凋亡。lncRNA MAGI2-AS3是肺癌潜在分子治疗靶点。