Cultured Non-small Cell Lung Cancer Cells Research Articles

MiR-129 Weakens Proliferation of Non-Small Cell Lung Cancer Cells via Targeted Regulation of High-Mobility Group AT-Hook 2

This study investigated the role of micro ribonucleic acid (miR)-129 in non-small cell lung cancer (NSCLC) by examining its effects on cell proliferation and apoptosis, as well as its relationship with the high-mobility group AT-hook 2 (HMGA2) target gene. Human NSCLC tissues were collected, and cancerous cells and normal cells were isolated and cultured. In vitro cultured NSCLC cells were transfected with miR-129 mimics or HMGA2-small interfering RNA (siRNA). The expression levels of miR-129 and HMGA2 were measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), while cell proliferation was assessed using the cell counting kit-8 (CCK-8) assay. The targeted regulation between miR-129 and HMGA2 was examined using a luciferase reporter assay system, and protein expression was determined by Western blotting (WB). Flow cytometry was utilized to measure the cell apoptosis rate. NSCLC tissues and cells exhibited significantly decreased miR-129 expression and increased HMGA2 expression compared to normal tissues and cells. Transfection with miR-129 mimics and HMGA2-siRNA effectively reduced HMGA2 gene and protein expression in NSCLC cells, leading to decreased proliferation and increased apoptosis. The luciferase reporter assay confirmed targeted regulation between miR-129 and HMGA2. In summary, miR-129 may suppress NSCLC cell proliferation and induce apoptosis by targeting HMGA2 expression.

High expression of MYH9 inhibits apoptosis of non-small cell lung cancer cells through activating the AKT/c-Myc pathway

To investigate the role of myosin heavy chain 9 (MYH9) in regulation of cell proliferation, apoptosis, and cisplatin sensitivity of non-small cell lung cancer (NSCLC). Six NSCLC cell lines (A549, H1299, H1975, SPCA1, H322, and H460) and a normal bronchial epithelial cell line (16HBE) were examined for MYH9 expression using Western blotting. Immunohistochemical staining was used to detect MYH9 expression in a tissue microarray containing 49 NSCLC and 43 adjacent tissue specimens. MYH9 knockout cell models were established in H1299 and H1975 cells using CRISPR/Cas9 technology, and the changes in cell proliferation cell were assessed using cell counting kit-8 (CCK8) and clone formation assays; Western blotting and flow cytometry were used to detect apoptosis of the cell models, and cisplatin sensitivity of the cells was evaluated using IC50 assay. The growth of tumor xenografts derived from NSCLC with or without MYH9 knockout was observed in nude mice. MYH9 expression was significantly upregulated in NSCLC (P < 0.001), and the patients with high MYH9 expression had a significantly shorter survival time (P=0.023). In cultured NSCLC cells, MYH9 knockout obviously inhibited cell proliferation (P < 0.001), promoted cell apoptosis (P < 0.05), and increased their chemosensitivity of cisplatin. In the tumor-bearing mouse models, the NSCLC cells with MYH9 knockout showed a significantly lower growth rate (P < 0.05). Western blotting showed that MYH9 knockout inactivated the AKT/c- Myc axis (P < 0.05) to inhibit the expression of BCL2- like protein 1 (P < 0.05), promoted the expression of BH3- interacting domain death agonist and the apoptosis regulator BAX (P < 0.05), and activated apoptosis-related proteins caspase-3 and caspase-9 (P < 0.05). High expression of MYH9 contributes to NSCLC progression by inhibiting cell apoptosis via activating the AKT/c-Myc axis.

Pseudogene KRT17P3 drives cisplatin resistance of human NSCLC cells by modulating miR-497-5p/mTOR.

Chemoresistance is a major obstacle in non–small cell lung cancer (NSCLC) treatment. The pseudogene keratin 17 pseudogene 3 (KRT17P3) has been previously shown to be upregulated in lung cancer tissues of patients with cisplatin resistance. In the present study, RT‐qPCR was performed to evaluate KRT17P3 levels in plasma samples collected from 30 cisplatin‐resistant and 32 cisplatin‐sensitive patients. We found that the plasma level of KRT17P3 is upregulated in cisplatin‐resistant patients, and the increased expression of plasma KRT17P3 is associated with poor chemotherapy response. Functional studies demonstrated that KRT17P3 overexpression in cultured NSCLC cells increases cell viability and decreases apoptosis upon cisplatin treatment in vitro and in vivo, while KRT17P3 knockdown has the opposite effect. Mechanistically, bioinformatics analysis, RNA immunoprecipitation, and dual luciferase reporter assay indicated that KRT17P3 acts as a molecular sponge for miR‐497‐5p and relieves the binding of miR‐497‐5p to its target gene mTOR. Rescue experiments validated the functional interaction between KRT17P3, miR‐497‐5p, and mTOR. Taken together, our findings indicate that KRT17P3/miR‐497‐5p/mTOR regulates the chemosensitivity of NSCLC, suggesting a potential therapeutic target for cisplatin‐resistant NSCLC patients. KRT17P3 may be a potential peripheral blood marker of NSCLC patients resistant to cisplatin.

TRIM67 Promotes the Proliferation, Migration, and Invasion of Non-Small-Cell Lung Cancer by Positively Regulating the Notch Pathway.

Tripartite motif-containing 67 (TRIM67), an E3 ubiquitin ligase, belongs to the TRIM protein family. The relationship between TRIM67 and tumorigenesis is not fully clear. Here, we elucidated TRIM67 function in non-small cell lung cancer (NSCLC). TRIM67 immunostaining results were correlated with clinicopathological features. Moreover, the function of TRIM67 in cultured NSCLC cells was evaluated by MTT, colony formation, and Transwell assays. TRIM67 expression was associated with tumor size, lymph node metastasis, p-TNM stage, cancer cell differentiation, and poor prognosis. We altered TRIM67 expression in A549 and H1299 cell lines, and the results showed that TRIM67 promoted cell proliferation, migration, invasion and EMT by positively regulating the Notch pathway. Collectively, the results showed that TRIM67 promotes NSCLC progression through the Notch pathway and that TRIM67 expression is associated with clinicopathological features, indicating that TRIM67 may play an important role in promoting the development of NSCLC and could be applied as not only an important prognostic biomarker but also a therapeutic target in NSCLC.

Pigment epithelium-derived factor inhibits lung cancer migration and invasion by upregulating exosomal thrombospondin 1

Exosomes are implicated in cancer cell development, migration and invasion. Pigment epithelium-derived factor (PEDF) is a secreted anticancer protein that can regulate lung cancer progression; however, the role of PEDF in non-small cell lung cancer (NSCLC), including metastasis and cancer cell-derived exosome secretion, is unclear. In this study, we analyzed the effects of PEDF on exosome-mediated migration, invasion, and tumorigenicity of cultured NSCLC cells. The results showed that PEDF overexpression significantly reduced NSCLC invasion and migration, while inducing cell aggregation, whereas PEDF knockdown had the opposite effects. Exosomes from NSCLC cells treated with recombinant PEDF had a significantly reduced ability to promote cancer cell motility, migration, and invasion compared to exosomes from untreated cells. Exosomes from PEDF-treated cells contained thrombospondin 1 (THBS1), which inhibited cytoskeletal remodeling and exosome-induced lung cancer cell motility, migration, and invasion. Furthermore, PEDF-overexpressing NSCLC cells formed smaller xenograft tumors with higher THBS1 expression compared to control tumors. Our findings indicate that PEDF decreases the metastatic potential of NSCLC cells through regulation of THBS1 release in cancer cell-derived exosomes, thus uncovering a new mechanism of lung cancer progression.

Abstract 2421: SOD1 is required for tumor maintenance in a genetically engineered KRAS/TP53 non-small cell lung cancer mouse model

Abstract Lung cancer is the second most common cancer and the primary cause of cancer-related mortality globally. Over half a million people are estimated living with lung and bronchus cancer with a 5-year survival rate of 18%. Identifying and studying new drug targets are important for improving lung cancer patient survival. 80% to 85% of lung cancers are Non-small cell lung cancer (NSCLC). Knocking down and small molecule inhibition of Superoxide dismutase 1 (SOD1) has been shown to be cytotoxic to cultured NSCLC cells and mouse tumors, suggesting that SOD1 is important for NSCLC survival, thus presenting a promising therapeutic strategy. SOD1 rapidly converts superoxide anion to hydrogen peroxide. It is a critical component of the cellular antioxidant defense system. In addition, our laboratory has recently demonstrated that SOD1 has a novel function as a transcription factor that regulates oxidative stress response genes. Currently, there are no selective SOD1 inhibitors available to study physiological functions of SOD1. In our study, we show that genetically knockout SOD1 resulted in reduced tumor burden in lung cancer mouse model. Using mouse tumor-derived primary cancer cells, we further show that SOD1 is critical for NSCLC cell proliferation and survival. This study reveals novel functions of SOD1 that are of biological and translational significance, and provide further support for SOD1 as a promising therapeutic target for NSCLC. Citation Format: Xiaowen Wang, Justin Wong, Holly Van Remmen, Jessie Yanxiang Guo, Eileen White, X. F. Steven Zheng. SOD1 is required for tumor maintenance in a genetically engineered KRAS/TP53 non-small cell lung cancer mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2421.

Abstract 1975: Disulfiram targets hypoxia-induced cancer stem cells and reverses chemoresistance in non-small cell lung cancer

Abstract Background: This study aims to repurpose disulfiram (DS), a drug used to treat alcohol dependence, into an effective treatment for non-small cell lung cancer (NSCLC). NSCLC is the leading cause of cancer related death worldwide because of early metastasis and chemoresistance. Cancer stem cells (CSCs) play a key role in resistance and metastasis. Our previous studies indicate that tumor hypoxia induced activation of the nuclear factor-κB (NF-κB) pathway, a pivotal regulator of CSCs. Therefore, development of an NF-κB and CSCs targeting drug will improve NSCLC therapeutic outcomes. New drug development is an expensive and time-consuming procedure. Cytotoxicity of DS is copper (II) (Cu)-dependent. DS/Cu induces reactive oxygen species, inhibits NF-κB activity and demonstrates excellent in vitro anti-CSCs activity in a wide range of cancers. The clinical application of DS as an anticancer drug is impeded by its very short half-life in the bloodstream. To improve the drug delivery efficiency, we developed a poly lactic-co-glycolic-DS (PLGA-DS), which demonstrates strong anti-cancer efficacy in mouse NSCLC models. Methods: NSCLC cell line A549 and H23 cultured as spheroids, hypoxia and PCDNA-3.1 NF-κB p65 transfect A659 cell lines. The cytotoxic effect of DS/Cu analyzed using sphere reformation, clonogenic and MTT assays. Flow cytometric analysis to detect CSC markers ALDH and CD44, and analysis of apoptosis by Annexin V. Western blot analysis to determine expression of embryonic stem cell markers Nanog and OCT4, and identify the importance of the NF-κB pathway together with HIF and including expression of associated apoptotic proteins Bax and Bcl2. Results: CSC and hypoxic cultured cells expressed high levels of CSC markers and were resistant to first and second line NSCLC anticancer drugs (doxorubicin, oxaliplatin, paclitaxel and gemcitabine). High NF-κB expression was detected in CSCs and hypoxia-cultured NSCLC cell lines. After transfection with p65 subunit of NF-κB, A549 cells expressed CSC markers and became resistant to a wide range of anticancer drugs. DS (5-10 nM) supplemented with Cu (10 μM) induced cytotoxicity to hypoxic cultured NSCLC cells, DS (1 μM) in combination with Cu inhibited sphere reformation. DS/Cu effectively inhibited NF-κB activity, abolished the CSC population and synergistically enhanced the cytotoxicity of the above conventional anticancer drugs. Our study also shows that PLGA-DS extends the half-life of free DS in the blood stream from 30 seconds to 7 hours. Intravenous injection of PLG-DS in combination with oral Cu can effectively inhibit the growth of subcutaneous and lung NSCLC xenografts. Conclusion: DS/Cu specifically inhibits NF-κB pathway and targets CSC in NSCLC cell lines. PLGA encapsulation improves delivery of DS which demonstrated very strong anticancer activity in NSCLC xenografts in vivo. Citation Format: Kate Butcher, Vinodh Kannappan, Karim Azar, Rajagopal Kilari, Ogechi Nkeonye, Mark R. Morris, Christopher McConville, Yaohe Wang, Weiguang Wang. Disulfiram targets hypoxia-induced cancer stem cells and reverses chemoresistance in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1975.

MicroRNA-29c inhibits proliferation and promotes apoptosis in non-small cell lung cancer cells by targeting VEGFA.

Non-small cell lung cancer (NSCLC) is a primary sub-type of lung cancer with a high incidence rate and poor prognosis. The primary therapeutic treatment for NSCLC is chemotherapy, which is considered to be ineffective and excessively toxic. Novel therapeutic methods, particularly molecular targeted therapy, have attracted considerable attention. MicroRNAs (miRs) are reported to be potential biomarkers and targeted agents with roles in various types of tumors. Herein, the present study presented the observation of aberrant low expression of miR‑29c and associated overexpression of vascular endothelial growth factorA (VEGFA) in NSCLC tumor tissues. The effects of miR‑29c upon NSCLC tumor progression, including cell proliferation and cellular apoptosis, were investigated. The possible regulatory mechanism of action of miR‑29c on its direct target VEGFA and the phosphatidylinositol 3‑kinase (PI3K)/RAC‑α serine/threonine‑protein kinase (Akt) signaling pathway was examined using multiple methods, including reverse transcription-quantitative polymerase chain reaction analysis, dual luciferase assay and western blot analysis. The results demonstrated that miR‑29c expression was downregulated in NSCLC tumor tissues compared with normal tissues. A marked negative correlation in the expression of miR‑29c and VEGFA was observed in clinical NSCLC tissues and cultured NSCLC cells. Overexpression of miR‑29c may inhibit cell proliferation and accelerate the cellular apoptosis rate of NSCLC tumor cells. Furthermore, the overexpression of miR‑29c was demonstrated to be able to downregulate the expression levels of VEGFA and PI3K/Akt signaling pathway‑associated proteins. The results of the present study suggested that miR‑29c might regulate NSCLC tumor progression by targeting VEGFA.

Twist may be associated with invasion and metastasis of hypoxic NSCLC cells.

Hypoxia promotes tumor invasion and metastasis via multiple mechanisms, including epithelial-mesenchymal transition (EMT). Twist, an EMT regulator, has been disclosed to associate with invasion and metastasis as well as poor prognosis of many malignancies. However, it remains undefined whether Twist is involved in invasion and metastasis of hypoxic non-small cell lung cancer (NSCLC). In this study, protein levels of Twist, hypoxia-inducible factor-1α (HIF-1α), and EMT markers (E-cadherin and vimentin) were examined by immunohistochemistry in 76 lung cancer tissues from NSCLC patients. Expression of Twist and its correlation with HIF-1α, E-cadherin, and vimentin were analyzed. Small interfering RNA (siRNA) against Twist was used to knockdown Twist expression in hypoxic NSCLC cells, A549 and NCI-H460. Cellular invasion and protein levels of Twist, E-cadherin, and vimentin were evaluated by matrigel invasion assay and Western blot, respectively. Our results showed that in clinical samples, there was a significant association between Twist expression and differentiation degree, lymph node metastasis, and TNM stage. Correlation analysis demonstrated that expression of Twist was negatively correlated with E-cadherin expression, but positively associated with HIF-1α and vimentin expression. In cultured NSCLC cells, Twist messenger RNA (mRNA) and protein levels were upregulated under hypoxia, while knockdown of Twist suppressed potentiated invasion and expression of mesenchymal marker vimentin induced by hypoxia. Protein level of increased epithelial marker E-cadherin was shown along with Twist downregulation. These findings suggest that Twist promoting hypoxic invasion and metastasis of NSCLC may be associated with altered expression of EMT markers. Inhibition of Twist may be of therapeutic significance.

Aptamer-Dendrimer Bioconjugates for Targeted Delivery of miR-34a Expressing Plasmid and Antitumor Effects in Non-Small Cell Lung Cancer Cells.

Metastasis and drug resistance are major barriers for the treatment of non-small cell lung cancer (NSCLC). To explore new therapeutic options, we successfully encapsulated MicroRNA-34a (miR-34a), a potent endogenous tumor suppressor in NSCLC into S6 aptamer-conjugated dendrimer to form lung cancer-targeted gene delivery nanoparticles (PAM-Ap/pMiR-34a NPs). PAM-Ap/pMiR-34a NPs had a diameter of 100–200 nm and Zeta potential of ~30 mV at applied N/P ratio. The aptamer conjugation significantly improved cellular uptake as well as gene transfection efficiency of PAM-Ap/pMiR-34a NPs in cultured NSCLC cells. We showed that PAM-Ap/pMiR-34a NPs enhanced the regulation of targeted genes, BCL-2 and p53 in vitro. In addition, we revealed PAM-Ap/pMiR-34a NPs significantly inhibited cell growth, migration, invasion and induced apoptosis of lung cancer cells compared with non-targeted NPs. The method provided a novel therapeutic strategy for the experimental treatment of NSCLC.

Regulation of MALAT1 expression by TDP43 controls the migration and invasion of non-small cell lung cancer cells in vitro

MALAT1 is a non-coding RNA overexpressed in non-small cell lung cancer (NSCLC). TDP-43 is a ubiquitously expressed, MALAT1-binding protein implicated in cancer development. We hypothesized that MALAT1 expression level is regulated in lung cancer by TDP-43. We analyzed their functions in cultured NSCLC cells. Downregulation of MALAT1 or TDP-43 expression by siRNA not only markedly suppressed NSCLC cell growth, as measured by the MTT assay in vitro cultured NSCLC cells (P < 0.05), but also noticeably impaired the migration and invasion of NSCLC cells, as analyzed by the migration and invasion assay. We also confirm that TDP-43 directly bound to MALAT1 RNA by a RNA immunoprecipitation (RIP) assay and by luciferase reporter activity assay. In a RT-PCR assay, silencing TDP-43 expression effectively decreased MALAT1 RNA transcript level. In contrast, TDP-43 overexpression markedly increased MALAT1 transcript level. In summary, these findings demonstrated that MALAT1 expression by regulation of TDP-43 controls cellular growth, migration, and invasion of NSCLCs.

MicroRNA-205 Promotes Cell Proliferation of Non-Small Cell Lung Cancer by Targeting Smad4

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the leading cause of cancerrelated death worldwide. Despite recent advances in cancer diagnosis and treatment, the survival rate of NSCLC patients remains dismally low. There is an urgent need for better mechanistic understanding and development of novel diagnostic and treatment strategies against this malignant disease. MicroRNAs (miRNAs), a class of 19- to 24- base pair non-coding RNAs, have increasingly been implicated as crucial regulators of NSCLC malignancy, and promising biomarkers and/or therapeutic targets for such aggressive disease. Here, we report clinical, molecular, and functional studies of miR-205 in NSCLC. Our analyses of an NSCLC patient cohort showed that expression of miR-205 in primary tumors was 7-fold higher than their corresponding adjacent noncancerous tissues. However, miR-205 was not associated with tumor stage, smoking status, age, or gender, implying a functional link to earlystage tumorigenesis of NSCLC. To test this possibility, we turned our attention to Smad4, a putative target of miR-205 and a widely recognized tumor suppressor. As expected, the expression of Smad4 mRNA in primary tumors of our patient cohort was lower than their normal counterparts. Importantly, we detected a strong negative association between miR-205 and Smad4 in patient tumor tissues. With these clinical leads, we next evaluated the molecular and functional links between these two distinct types of molecules. Our initial mutagenesis analyses showed that miR-205 repressed the expression of Smad4 by directly targeting the 3’-UTR region of its mRNA. Subsequently, we found that overexpression of miR-205 enhanced the proliferation of cultured NSCLC cells. Conversely, siRNA-directed knockdown of Smad4 markedly suppressed tumor cell proliferation. Moreover, our MassARRAY technology-based analyses showed that the DNA methylation of the -77CpG site in the promoter region of miR-205 was significantly impaired in patient tumor tissues. Taken together, our study for the first time provides clinical, molecular and functional evidence on the critical roles of miR-205 in human NSCLC. In particular, our analyses demonstrate that miR-205 drives tumor cell proliferation of NSCLC by directly downregulating Smad4 expression. As such, our findings strongly support the potential of miR-205 as a candidate biomarker and therapeutic target for the diagnosis and treatment of NSCLC.

Abstract 5194: MiR-200c expression and methylation status determines epithelial characteristics of NSCLC

Abstract Background: MicroRNA (miR)-200 family members are frequently silenced in advanced cancer and have been implicated in the process of epithelial-to-mesenchymal transition (EMT) and tumor invasion. In this study, we investigated the roles of miR-200c in non-small cell lung cancer (NSCLC). Materials and Methods: We analyzed miR-200c promoter methylation status by methylation specific PCR and expression by quantitative RT-PCR in 34 NSCLC cell lines and 10 NSCLC clinical samples. To eliminate the effects of contamination of normal lung epithelial cells and mesenchymal cells in clinical samples, we used primary cultured NSCLC cells obtained by surgical resection. We assessed the association of miR-200c status with histology, EMT-related protein expression, and genetic alteration. Results: Mir-200c was methylated in 10 (30%) NSCLC cell lines and partially methylated in 7 (21%) cell lines. Expression of miR-200c was silenced in all methylated cell lines and restored with 5-aza-2′-deoxycytidine treatment. In cell lines with miR-200c methylation and silenced, protein expression of epithelial markers was reduced and mesenchymal markers were increased. Introduction of miR-200c into highly invasive cells with miR-200c silencing inhibited cell invasion. Interestingly, miR-200c was unmethylated and not silenced in many EGFR mutated NSCLC cell lines and clinical samples. In HEK293T cells stably transfected with wild-type EGFR, mutant EGFR, wild-type KRAS, or mutant KRAS, miR-200c expression was up-regulated only in mutant EGFR transfectant. Conclusions: Mir-200c expression was regulated by promoter methylation in NSCLC, and related to epithelial characteristics and cell invasion. In EGFR mutated NSCLC cells, miR-200c was generally unmethylated and expressed, suggesting the existence of mechanism that retain EGFR mutated NSCLC cells to the epithelial state through the miR-200c expression. Citation Format: Kazuhiko Shien, Shinichi Toyooka, Junichi Soh, Hiromasa Yamamoto, Shinsuke Hashida, Ken Suzawa, Tomoaki Otsuka, Hiroaki Asano, Kazunori Tsukuda, Shinichiro Miyoshi. MiR-200c expression and methylation status determines epithelial characteristics of NSCLC. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5194. doi:10.1158/1538-7445.AM2014-5194

Phospholipase C ε‐1 inhibits p53 expression in lung cancer

The pathogenesis of lung cancer is to be further investigated. Recent reports indicate that phospholipase C ε-1 (PLCE1) is a critical molecule involved in tumour growth. This study aims to investigate the role of PLCE1 in the regulation of apoptosis in lung cancer cells. In this study, the surgically removed non-small-cell lung cancer (NSCLC) tissue was collected from 36 patients. Single NSCLC cells were prepared from the tissue, in which immune cells of CD3(+) , CD11c(+) , CD19(+) , CD68(+) and CD14(+) were eliminated by magnetic cell sorting. The expression of PLCE1 and p53 was assessed by quantitative real-time polymerase chain reaction and Western blotting. Apoptosis of NSCLC cells was analysed by flow cytometry. The results showed that, in cultured NSCLC cells, high levels of PLCE1 and low levels p53 were detected; the two molecules showed a negative correlation (p < 0.01). The addition of anti-PLCE1 antibody increased the expression of p53 in NSCLC cells, which increased the frequency of apoptotic NSCLC cells. We conclude that NSCLC cells express high levels of PLCE1, which suppresses the expression of p53 in NSCLC cells. PLCE1 can be a therapeutic target of NSCLC.

Elevated SP-1 Transcription Factor Expression and Activity Drives Basal and Hypoxia-induced Vascular Endothelial Growth Factor (VEGF) Expression in Non-Small Cell Lung Cancer

VEGF plays a central role in angiogenesis in cancer. Non-small cell lung cancer (NSCLC) tumors have increased microvascular density, localized hypoxia, and high VEGF expression levels; however, there is a lack of understanding of how oncogenic and tumor microenvironment changes such as hypoxia lead to greater VEGF expression in lung and other cancers. We show that NSCLC cells secreted higher levels of VEGF than normal airway epithelial cells. Actinomycin D inhibited all NSCLC VEGF secretion, and VEGF minimal promoter-luciferase reporter constructs were constitutively active until the last 85 base pairs before the transcription start site containing three SP-1 transcription factor-binding sites; mutation of these VEGF promoter SP-1-binding sites eliminated VEGF promoter activity. Furthermore, dominant negative SP-1, mithramycin A, and SP-1 shRNA decreased VEGF promoter activity, whereas overexpression of SP-1 increased VEGF promoter activity. Chromatin immunoprecipitation assays demonstrated SP-1, p300, and PCA/F histone acetyltransferase binding and histone H4 hyperacetylation at the VEGF promoter in NSCLC cells. Cultured NSCLC cells expressed higher levels of SP-1 protein than normal airway epithelial cells, and double-fluorescence immunohistochemistry showed a strong correlation between SP-1 and VEGF in human NSCLC tumors. In addition, hypoxia-driven VEGF expression in NSCLC cells was SP-1-dependent, with hypoxia increasing SP-1 activity and binding to the VEGF promoter. These studies are the first to demonstrate that overexpression of SP-1 plays a central role in hypoxia-induced VEGF secretion.

Antiproliferative Effect of Newcastle Disease Virus Strain D90 on Human Lung Cancer Cell Line A549

Newcastle disease virus (NDV) and variants of this virus have oncolytic properties and are potential anticancer agents. The objective of this study was to compare the effect of NDV strain D90 and strain D93 isolated from natural sources on human non-small cell lung cancer (NSCLC) cell line A549. We determined the 50% embryo infective dose (EID50) and 50% tissue culture infective dose (TCID50) of the NDV strains. The MTT assay was used to evaluate the effects of NDV strains on cell viability. We determined the expression of Annexin V and Bcl-2 proteins in NDV-infected cells. Light microscopy and electron microscopy indicated that the D90 strain significantly altered cell morphology and reduced cell viability, while strain D93 had negligible effects. Neither strain had a significant effect on normal cultured fetal liver cells. We used acridine orange staining to show that strain D90 (but not strain D93) induced nuclear fragmentation of A549 cells. An Annexin V-based apoptosis assay indicated that strain D90 (but not strain D93) caused significant apoptosis of A549 cells. Moreover, strain D90 (but not strain D93) significantly repressed the expression of Bcl-2 (an antiapoptotic protein) in A549 cells. Taken together, our results indicate that NDV strain D90 (but not strain D93) had no significant effect on normal cultured cells, but induced apoptosis of cultured NSCLC cells via a caspase-dependent pathway. These results suggest that NDV strain D90 has potential as an anticancer agent.

Src-Family Kinases Are Activated in Non-Small Cell Lung Cancer and Promote the Survival of Epidermal Growth Factor Receptor-Dependent Cell Lines

The role of Src-family kinases (SFKs) in non-small cell lung cancer (NSCLC) has not been fully defined. Here we addressed this question by examining SFK phosphorylation in NSCLC biopsy samples and using genetic and pharmacological approaches to inhibit SFK expression and activity in cultured NSCLC cells. Immunohistochemical analysis of NSCLC biopsy samples using a Tyr416 phosphorylation-specific, pan-SFK antibody revealed staining in 123 (33%) of 370 tumors. Because c-Src is known to be both an upstream activator and downstream mediator of epidermal growth factor receptor (EGFR), we next investigated SFK phosphorylation in a panel of NSCLC cell lines, including ones that depend on EGFR for survival. The EGFR-dependent NSCLC cell lines HCC827 and H3255 had increased phosphorylation of SFKs, and treatment of these cells with an SFK inhibitor (PP1 or SKI-606) induced apoptosis. PP1 decreased phosphorylation of EGFR, ErbB2, and ErbB3 and strikingly enhanced apoptosis by gefitinib, an EGFR inhibitor. HCC827 cells transfected with c-Src short hairpin RNA exhibited diminished phosphorylation of EGFR and ErbB2 and decreased sensitivity to apoptosis by PP1 or gefitinib. We conclude that SFKs are activated in NSCLC biopsy samples, promote the survival of EGFR-dependent NSCLC cells, and should be investigated as therapeutic targets in NSCLC patients.