Targeting Lactate Dehydrogenase-A Inhibits Tumorigenesis and Tumor Progression in Mouse Models of Lung Cancer and Impacts Tumor-Initiating Cells

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NEK2 plays an active role in Tumorigenesis and Tumor Microenvironment in Non-Small Cell Lung Cancer

Abnormal expression and dysfunction of Never-in-mitosis-A-related kinase 2 (NEK2) result in tumorigenesis. High levels of NEK2 are related to malignant progression, drug resistance, and poor prognosis. However, the relationship between NEK2 levels and the occurrence of non-small cell lung cancer (NSCLC) remains unknown. This study aimed to explore the impacts of NEK2 on the oncogenesis of NSCLC and the tumor microenvironment. Downregulation of NEK2 inhibited A549 and H1299 cell proliferation, migration, and invasion, blocking cell cycle at the G0/G1 phase. Loss of NEK2 inhibited the release of IL-10 from tumor cells, M2-like polarization of macrophages, angiogenesis, and vascular endothelial cell migration. Furthermore, NEK2 deficiency inhibited tumor growth in vivo. Taken together, NEK2 knockdown inhibited the occurrence and development of NSCLC, M2 polarization of macrophages, and angiogenesis. The abnormal expression of NEK2 might not only indicate tumor progression and patient prognosis but also serve as a potential molecular therapeutic target with great development prospects.     

Inhibitory Activity of (+)-Usnic Acid against Non-Small Cell Lung Cancer Cell Motility

Lichens are symbiotic organisms that produce various unique chemicals that can be used for pharmaceutical purposes. With the aim of screening new anti-cancer agents that inhibit cancer cell motility, we tested the inhibitory activity of seven lichen species collected from the Romanian Carpathian Mountains against migration and invasion of human lung cancer cells and further investigated the molecular mechanisms underlying their anti-metastatic activity. Among them, Alectoria samentosa, Flavocetraria nivalis, Alectoria ochroleuca, and Usnea florida showed significant inhibitory activity against motility of human lung cancer cells. HPLC results showed that usnic acid is the main compound in these lichens, and (+)-usnic acid showed similar inhibitory activity that crude extract have. Mechanistically, β-catenin-mediated TOPFLASH activity and KITENIN-mediated AP-1 activity were decreased by (+)-usnic acid treatment in a dose-dependent manner. The quantitative real-time PCR data showed that (+)-usnic acid decreased the mRNA level of CD44, Cyclin D1 and c-myc, which are the downstream target genes of both β-catenin/LEF and c-jun/AP-1. Also, Rac1 and RhoA activities were decreased by treatment with (+)-usnic acid. Interestingly, higher inhibitory activity for cell invasion was observed when cells were treated with (+)-usnic acid and cetuximab. These results implied that (+)-usnic acid might have potential activity in inhibition of cancer cell metastasis, and (+)-usnic acid could be used for anti-cancer therapy with a distinct mechanisms of action.     

吸入伊洛前列素对非小细胞肺癌细胞化疗敏感性的影响

目的:研究吸入伊洛前列素对非小细胞肺癌(NSCLC)细胞化疗敏感性的影响。方法:研究对象为2014年8月至2015年8月在我院住院治疗的40例NSCLC患者,随机分为治疗组和对照组。所有患者均予以吉西他滨联合顺铂化疗,治疗组在化疗同时予以吸入伊洛前列素。ELISA检测患者治疗前后患者血清中HIF-1α和VEGF表达水平的变化,采用Karnofsky评分评价患者功能状况,并对比两组疗效及毒副反应。结果:治疗组有效率(RR)和控制率(CDR)显著高于对照组(P0.05);治疗组Karnofsky评分改善率优于对照组(P0.05);治疗组毒副反应发生率低于对照组(P0.05);治疗后两组血清中HIF-1α和VEGF的表达水平均低于治疗前,治疗组治疗后1天、21天血清中HIF-1α和VEGF的表达水平显著低于对照组同期,且治疗后21天表达水平显著低于治疗后1天(P0.05)。结论:吸入伊洛前列素能通过调节HIF-1α和VEGF水平改善NSCLC细胞化疗敏感性,且疗效安全显著,预后好。     

过表达NOLC1诱导人非小细胞肺癌细胞凋亡

人核仁磷酸化蛋白1 (Nucleolar and coiledbody phosphoprotein 1,NOLC1)在癌症的发生发展过程中起着至关重要的调控作用,为探讨NOLC1对肺癌细胞的作用,本研究通过Gateway系统构建重组NOLC1腺病毒载体,成功包装NOLC1腺病毒后,分别感染正常人类胚胎肺细胞(HEL)和非小细胞肺癌细胞(A549细胞),过表达NOLC1。通过MTT实验、AnnexinV-APC/PI双染法和线粒体膜电位实验,证明与HEL细胞相比,NOLC1的过表达对A549细胞的活性降低、凋亡增加、线粒体膜电位下降影响较为显著;通过Real-time PCR检测Caspase家族、TNF与受体家族和BCL2家族基因的表达,发现过表达NOLC1明显上调了A549细胞中促凋亡基因的表达,下调了抗凋亡基因的表达,其中两种重要的促凋亡蛋白CASP8和BAX均显著上调,但是在HEL细胞中这种影响不明显。研究结果表明过表达NOLC1蛋白通过对线粒体通路和死亡受体通路的共同作用,对非小细胞癌具有显著的抗肿瘤活性。     

Circulating Endothelial Cells and Microparticles as Prognostic Markers in Advanced Non-Small Cell Lung Cancer

Background

Circulating endothelial cells and microparticles have prognostic value in cancer, and might be predictors of response to chemotherapy and antiangiogenic treatments. We have investigated the prognostic value of circulating endothelial cells and microparticles in patients treated for advanced non-small cell lung cancer.

Methodology/Principal Findings

Peripheral blood samples were obtained from 60 patients before first line, platinum-based chemotherapy +/− bevacizumab, and after the third cycle of treatment. Blood samples from 60 healthy volunteers were also obtained as controls. Circulating endothelial cells were measured by an immunomagnetic technique and immunofluorescence microscopy. Phosphatidylserine-positive microparticles were evaluated by flow cytometry. Microparticle-mediated procoagulant activity was measured by the endogen thrombin generation assay. Results: pre- and posttreatment levels of markers were higher in patients than in controls (p<0.0001). Elevated levels of microparticles were associated with longer survival. Elevated pretreatment levels of circulating endothelial cells were associated with shorter survival.

Conclusions/Significance

Circulating levels of microparticles and circulating endothelial cells correlate with prognosis, and could be useful as prognostic markers in patients with advanced non-small cell lung cancer.     

miR-146a Inhibits Cell Growth,Cell Migration and Induces Apoptosis in Non-Small Cell Lung Cancer Cells

Aberrant expression of microRNA-146a (miR-146a) has been reported to be involved in the development and progression of various types of cancers. However, its role in non-small cell lung cancer (NSCLC) has not been elucidated. The aim of this study was to investigate the contribution of miR-146a to various aspects of the malignant phenotype of human NSCLCs. In functional experiments, miR-146a suppressed cell growth, induced cellular apoptosis and inhibited EGFR downstream signaling in five NSCLC cell lines (H358, H1650, H1975, HCC827 and H292). miR-146a also inhibited the migratory capacity of these NSCLC cells. On the other hand, miR-146a enhanced the inhibition of cell proliferation by drugs targeting EGFR, including both TKIs (gefitinib, erlotinib, and afatinib) and a monoclonal antibody (cetuximab). These effects were independent of the EGFR mutation status (wild type, sensitizing mutation or resistance mutation), but were less potent compared to the effects of siRNA targeting of EGFR. Our results suggest that these effects of miR-146a are due to its targeting of EGFR and NF-κB signaling. We also found, in clinical formalin fixed paraffin embedded (FFPE) lung cancer samples, that low expression of miR-146a was correlated with advanced clinical TNM stages and distant metastasis in NSCLC (P<0.05). The patients with high miR-146a expression in their tumors showed longer progression-free survival (25.6 weeks in miR-146a high patients vs. 4.8 weeks in miR-146a low patients, P<0.05). miR-146a is therefore a strong candidate prognostic biomarker in NSCLC. Thus inducing miR-146a might be a therapeutic strategy for NSCLC.     

Quantification of Rare Circulating Tumor Cells in Non-Small Cell Lung Cancer by Ligand-Targeted PCR

Background

Quantification of circulating tumor cells (CTC) is valuable for evaluation of non-small cell lung cancer (NSCLC). The sensitivity of current methods constrains their use to detect rare CTCs in early stage. Here we evaluate a novel method, ligand-targeted polymerase chain reaction (LT-PCR), that can detect rare CTCs in NSCLC patients.

Methods

CTCs were enriched by immunomagnetic depletion of leukocytes and then labeled by a conjugate of a tumor-specific ligand and an oligonucleotide. After washing off free conjugates, the bound conjugates were stripped from CTCs and then analyzed by qPCR. To evaluate the clinical utility, blood samples were obtained from 72 NSCLC patients (33 initially diagnosed and 39 on chemotherapy), 20 benign patients, and 24 healthy donors.

Results

Experiments with healthy blood spiked with tumor cells indicated the LT-PCR allows specific detection of CTC. The clinical study showed that the initially diagnosed patients have an average of 20.8 CTC units with metastatic diseases, 11.8 CTC units with localized diseases, and 6.0 CTC units with benign diseases. With the threshold of 8.5 CTC units, the assay can detect 80% of stage I/II, 67% of stage III, and 93% of stage IV cancer. With the benign patients and healthy donors as control group, the method can detect cancer with a sensitivity of 81.8% and a specificity of 93.2%.

Conclusion

The LT-PCR would allow quantification of CTC in NSCLC patients at a more sensitive level, providing a potential tool for stratifying malignant lung diseases, especially at early stage.     

Anti-Tumor Activity of Yuanhuacine by Regulating AMPK/mTOR Signaling Pathway and Actin Cytoskeleton Organization in Non-Small Cell Lung Cancer Cells

Yuanhuacine (YC), a daphnane diterpenoid from the flowers of Daphne genkwa, exhibited a potential growth inhibitory activity against human non-small cell lung cancer (NSCLC) cells. YC also suppressed the invasion and migration of lung cancer cells. However, the precise molecular mechanisms remain to be elucidated. In the present study, we report that YC significantly activated AMP-activated protein kinase (AMPK) signaling pathway and suppressed mTORC2-mediated downstream signaling pathway in H1993 human NSCLC cells. AMPK plays an important role in energy metabolism and cancer biology. Therefore, activators of AMPK signaling pathways can be applicable to the treatment of cancer. YC enhanced the expression of p-AMPKα. The co-treatment of YC and compound C (an AMPK inhibitor) or metformin (an AMPK activator) also confirmed that YC increases p-AMPKα. YC also suppressed the activation of the mammalian target of rapamycin (mTOR) expression, a downstream target of AMPK. Further study revealed that YC modulates mTORC2-associated downstream signaling pathways with a decreased expressions of p-Akt, p-protein kinase C alpha (PKCα), p-ras-related C3 botulinum toxin substrate 1 (Rac1) and filamentous actin (F-actin) that are known to activate cell growth and organize actin cytoskeleton. In addition, YC inhibited the tumor growth in H1993 cell-implanted xenograft nude mouse model. These data suggest the YC could be a potential candidate for cancer chemotherapeutic agents derived from natural products by regulating AMPK/mTORC2 signaling pathway and actin cytoskeleton organization.     

PAK1 Kinase Promotes Cell Motility and Invasiveness through CRK-II Serine Phosphorylation in Non-Small Cell Lung Cancer Cells

The role of c-Crk (CRK) in promoting metastasis is well described however the role of CRK phosphorylation and the corresponding signaling events are not well explained. We have observed CRK-II serine 41 phosphorylation is inversely correlated with p120-catenin and E-cadherin expressions in non-small cell lung cancer (NSCLC) cells. Therefore, we investigated the role of CRK-II serine 41 phosphorylation in the down-regulation of p120-catenin, cell motility and cell invasiveness in NSCLC cells. For this purpose, we expressed phosphomimetic and phosphodeficient CRK-II serine 41 mutants in NSCLC cells. NSCLC cells expressing phosphomimetic CRK-II seine 41 mutant showed lower p120-catenin level while CRK-II seine 41 phosphodeficient mutant expression resulted in higher p120-catenin. In addition, A549 cells expressing CRK-II serine 41 phosphomimetic mutant demonstrated more aggressive behavior in wound healing and invasion assays and, on the contrary, expression of phosphodeficient CRK-II serine 41 mutant in A549 cells resulted in reduced cell motility and invasiveness. We also provide evidence that PAK1 mediates CRK-II serine 41 phosphorylation. RNAi mediated silencing of PAK1 increased p120-catenin level in A549 and H157 cells. Furthermore, PAK1 silencing decreased cell motility and invasiveness in A549 cells. These effects were abrogated in A549 cells expressing phosphomimetic CRK-II serine 41. In summary, these data provide evidence for the role of PAK1 in the promotion of cell motility, cell invasiveness and the down regulation of p120-catenin through CRK serine 41 phosphorylation in NSCLC cells.     

Folate Receptor-Positive Circulating Tumor Cells as a Novel Diagnostic Biomarker in Non-Small Cell Lung Cancer

The study aims to determine the efficacy and feasibility of a novel folate receptor (FR)-based circulating tumor cell (CTC) detection method in the diagnosis of non-small cell lung cancer (NSCLC). CTCs were collected from 3 ml of blood based on negative enrichment by immunomagnetic beads and then labeled by a conjugate of a tumor-specific ligand folate and an oligonucleotide. After washing off redundant conjugates, the bound conjugates were removed and analyzed by quantitative polymerase chain reaction. The captured cells were validated as tumor cells by immunofluorescence staining. In the evaluation of clinical utility, the results showed that the CTC levels of 153 patients with NSCLC were significantly higher than the controls (49 healthy donors and 64 patients with benign lung diseases; P < .001). With a threshold of 8.64 CTC units, the method showed a sensitivity of 73.2% and a specificity of 84.1% in the diagnosis of NSCLC, especially a sensitivity of 67.2% in stage I disease. Compared with the existing clinical biomarkers such as neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), cyfra21-1, and squamous cell carcinoma antigen (SCC Ag), the method showed the highest diagnostic efficiency (area under the curve, 0.823; 95% confidence interval, 0.773–0.874). Together, our results demonstrated that FR-positive CTCs were feasible diagnostic biomarkers in patients with NSCLC, as well as in early-stage tumors.     

雷公藤红素对非小细胞肺癌细胞株H1299增殖与凋亡的影响

目的：研究雷公藤红素对非小细胞肺癌细胞株H1299的杀伤作用及相关调控机制。方法：用细胞计数法测定不同浓度雷公藤红素对H1299细胞增殖的影响;用流式细胞仪检测H1299细胞的细胞周期;用Western blotting检测剪切的（cleaved）聚ADP核糖聚合酶（PARP）、cleaved caspase-3和低氧诱导因子-1（HIF-1）的表达水平;用DCF-DA染色和荧光显微镜检测细胞内的活性氧（ROS）水平;用萤光素酶活性测定法检测NFκB的活性。结果：雷公藤红素以时间和剂量依赖性的方式抑制H1299细胞的增殖,并使细胞阻滞在G2/M期。同时,雷公藤红素显著上调cleaved PARP和cleaved caspase-3的表达,提高细胞内的ROS水平,并且抑制NFκB的活性。结论：雷公藤红素以时间和剂量依赖性的方式抑制H1299细胞的增殖,并诱导caspase依赖性的细胞凋亡,具体机制与细胞内ROS的积累和NFκB的活性抑制有关。     

Depletion of HDAC6 Enhances Cisplatin-Induced DNA Damage and Apoptosis in Non-Small Cell Lung Cancer Cells

Histone deacetylase inhibitors (HDACi) are promising therapeutic agents which are currently used in combination with chemotherapeutic agents in clinical trials for cancer treatment including non-small cell lung cancer (NSCLC). However, the mechanisms underlying their anti-tumor activities remain elusive. Previous studies showed that inhibition of HDAC6 induces DNA damage and sensitizes transformed cells to anti-tumor agents such as etoposide and doxorubicin. Here, we showed that depletion of HDAC6 in two NSCLC cell lines, H292 and A549, sensitized cells to cisplatin, one of the first-line chemotherapeutic agents used to treat NSCLC. We suggested that depletion of HDAC6 increased cisplatin-induced cytotoxicity was due to the enhancement of apoptosis via activating ATR/Chk1 pathway. Furthermore, we showed that HDAC6 protein levels were positively correlated with cisplatin IC(50) in 15 NSCLC cell lines. Lastly, depletion of HDAC6 in H292 xenografts rendered decreased tumor weight and volume and exhibited increased basal apoptosis compared with the controls in a xenograft mouse model. In summary, our findings suggest that HDAC6 is positively associated with cisplatin resistance in NSCLC and reveal HDAC6 as a potential novel therapeutic target for platinum refractory NSCLC.     

TRIM59 Promotes the Proliferation and Migration of Non-Small Cell Lung Cancer Cells by Upregulating Cell Cycle Related Proteins

TRIM protein family is an evolutionarily conserved gene family implicated in a number of critical processes including inflammation, immunity, antiviral and cancer. In an effort to profile the expression patterns of TRIM superfamily in several non-small cell lung cancer (NSCLC) cell lines, we found that the expression of 10 TRIM genes including TRIM3, TRIM7, TRIM14, TRIM16, TRIM21, TRIM22, TRIM29, TRIM59, TRIM66 and TRIM70 was significantly upregulated in NSCLC cell lines compared with the normal human bronchial epithelial (HBE) cell line, whereas the expression of 7 other TRIM genes including TRIM4, TRIM9, TRIM36, TRIM46, TRIM54, TRIM67 and TRIM76 was significantly down-regulated in NSCLC cell lines compared with that in HBE cells. As TRIM59 has been reported to act as a proto-oncogene that affects both Ras and RB signal pathways in prostate cancer models, we here focused on the role of TRIM59 in the regulation of NSCLC cell proliferation and migration. We reported that TRIM59 protein was significantly increased in various NSCLC cell lines. SiRNA-induced knocking down of TRIM59 significantly inhibited the proliferation and migration of NSCLC cell lines by arresting cell cycle in G2 phase. Moreover, TRIM59 knocking down affected the expression of a number of cell cycle proteins including CDC25C and CDK1. Finally, we knocked down TRIM59 and found that p53 protein expression levels did not upregulate, so we proposed that TRIM59 may promote NSCLC cell growth through other pathways but not the p53 signaling pathway.     

Involvement of TRPC Channels in Lung Cancer Cell Differentiation and the Correlation Analysis in Human Non-Small Cell Lung Cancer

The canonical transient receptor potential (TRPC) channels are Ca²⁺-permeable cationic channels controlling the Ca²⁺ influx evoked by G protein-coupled receptor activation and/or by Ca²⁺ store depletion. Here we investigate the involvement of TRPCs in the cell differentiation of lung cancer. The expression of TRPCs and the correlation to cancer differentiation grade in non-small cell lung cancer (NSCLC) were analyzed by real-time PCR and immunostaining using tissue microarrays from 28 patient lung cancer samples. The association of TRPCs with cell differentiation was also investigated in the lung cancer cell line A549 by PCR and Western blotting. The channel activity was monitored by Ca²⁺ imaging and patch recording after treatment with all-trans-retinoic acid (ATRA). The expression of TRPC1, 3, 4 and 6 was correlated to the differentiation grade of NSCLC in patients, but there was no correlation to age, sex, smoking history and lung cancer cell type. ATRA upregulated TRPC3, TRPC4 and TRPC6 expression and enhanced Ca²⁺ influx in A549 cells, however, ATRA showed no direct effect on TRPC channels. Inhibition of TRPC channels by pore-blocking antibodies decreased the cell mitosis, which was counteracted by chronic treatment with ATRA. Blockade of TRPC channels inhibited A549 cell proliferation, while overexpression of TRPCs increased the proliferation. We conclude that TRPC expression correlates to lung cancer differentiation. TRPCs mediate the pharmacological effect of ATRA and play important roles in regulating lung cancer cell differentiation and proliferation, which gives a new understanding of lung cancer biology and potential anti-cancer therapy.     

RBP2 Induces Epithelial-Mesenchymal Transition in Non-Small Cell Lung Cancer

RBP2 has been found to actively participate in cancer progression. It inhibits the senescence of cancer cells, mediates cancer cell proliferation and promotes cancer metastasis. It is also essential to drug tolerance. However, the effects of RBP2 on epithelial-mesenchymal transition are still unknown. In this study, we analyzed the effects of RBP2 on epithelial-mesenchymal transition in non-small cell lung cancer. The results showed that RBP2 down-regulated the expression of E-cadherin by inhibiting the promoter activity of E-cadherin and up-regulated the expression of N-cadherin and snail via the activation of Akt signaling, and the overexpression of RBP2 induced epithelial-mesenchymal transition in non-small cell lung cancer cells. Our study further indicated thatRBP2 may be a potential target for anti-lung cancer therapy.