KRAS Dimerization Impacts MEK Inhibitor Sensitivity and Oncogenic Activity of Mutant KRAS.

The mechanism by which the wild-type KRAS allele imparts a growth inhibitory effect to oncogenic KRAS in various cancers, including lung adenocarcinoma (LUAD), is poorly understood. Here, using a genetically inducible model of KRAS loss of heterozygosity (LOH), we show that KRAS dimerization mediates wild-type KRAS-dependent fitness of human and murine KRAS mutant LUAD tumor cells and underlies resistance to MEK inhibition. These effects are abrogated when wild-type KRAS is replaced by KRASD154Q, a mutant that disrupts dimerization at the α4-α5 KRAS dimer interface without changing other fundamental biochemical properties of KRAS, both in vitro and in vivo. Moreover, dimerization has a critical role in the oncogenic activity of mutant KRAS. Our studies provide mechanistic and biological insights into the role of KRAS dimerization and highlight a role for disruption of dimerization as a therapeutic strategy for KRAS mutant cancers.

Requirement for epithelial p38α in KRAS-driven lung tumor progression.

Malignant transformation entails important changes in the control of cell proliferation through the rewiring of selected signaling pathways. Cancer cells then become very dependent on the proper function of those pathways, and their inhibition offers therapeutic opportunities. Here we identify the stress kinase p38α as a nononcogenic signaling molecule that enables the progression of KrasG12V-driven lung cancer. We demonstrate in vivo that, despite acting as a tumor suppressor in healthy alveolar progenitor cells, p38α contributes to the proliferation and malignization of lung cancer epithelial cells. We show that high expression levels of p38α correlate with poor survival in lung adenocarcinoma patients, and that genetic or chemical inhibition of p38α halts tumor growth in lung cancer mouse models. Moreover, we reveal a lung cancer epithelial cell-autonomous function for p38α promoting the expression of TIMP-1, which in turn stimulates cell proliferation in an autocrine manner. Altogether, our results suggest that epithelial p38α promotes KrasG12V-driven lung cancer progression via maintenance of cellular self-growth stimulatory signals.

E3 ubiquitin ligase PJA1 regulates lung adenocarcinoma apoptosis and invasion through promoting FOXR2 degradation.

Among all lung cancer cases, lung adenocarcinoma (LAC) represents nearly 40% and remains the leading cause of cancer deaths worldwide. Although the combination therapy of surgical treatment with radiotherapy, chemotherapy, and immunotherapy, has been used to treat LAC, unfortunately, high recurrence rates and poor survival remain. Therefore, novel prognostic markers and new targets for molecular targeted therapy in LAC is urgently needed. Fork-head box R2 (FOXR2) plays a key role in a wide range of cellular processes, including cellular proliferation, invasion, differentiation, and apoptosis, and it has been reported to be implicated in progression of LAC, thus inhibition of FOXR2 may be a novel targeting therapy for lung cancer. This current study found that E3 ligase PJA1 regulates ubiquitin-mediated degradation of FOXR2 and predicts good outcome of patients with LAC. In addition, it was showed force expression of PJA1 significantly inhibited LAC cells invasion and induced apoptosis in vitro through inactivating Wnt/ß-catenin signaling pathway. In short, our findings reveal that PJA1 could be a potential diagnostic and prognostic biomarkers and the PJA1- FOXR2 axis could be served as a promising target for LAC therapy.

Irreversible epidermal growth factor receptor inhibitor Z25h exhibits pronounced inhibition on non-small cell lung adenocarcinoma cell line Hcc827.

The epidermal growth factor receptor (EGFR) signaling is frequently activated in lung cancer. In our previous study, a new class of compounds containing pyrido[3,4-d]pyrimidine scaffold with an acrylamide moiety was designed as irreversible EGFR-tyrosine kinase inhibitors to overcome acquired EGFR-T790M resistance. In this study, we selected the most promising compound Z25h to further investigate its effects and the underlying mechanism against non-small cell lung adenocarcinoma cells in vitro. Four different non-small cell lung adenocarcinoma cell lines were selected to test the antiviability profile of Z25h, and Hcc827 was the most sensitive to the drug treatment. Z25h caused cell cycle arrest at G0-G1 phase, and triggered strong early apoptosis in Hcc827 cells at 0.1 µM and late apoptosis in A549, H1975 and H1299 cells at 10 µM by 48 h treatment. Z25h inhibited the activation of EGFR and its downstream PI3K/AKT/mTOR pathway in the four tested cell lines, leading to the inhibition of cellular biosynthetic and metabolic processes and the promotion of apoptotic process. However, the effect of Z25h on mitogen-activated protein kinase pathway varies from cell lines. In addition, Z25h sensitized H1975 cells to X-ray radiation, and it also enhanced the radiation effect on A549 cells, while no obvious effect of Z25h was observed on the cell viability inhibition of H1299 cells induced by radiation. Hereby, Z25h might be considered as a potential therapeutic drug candidate for non-small cell lung adenocarcinoma treatment.

Successful treatment of Afatinib plus Apatinib using for a lung adenocarcinoma patient with HER-2 V659D mutation: a rare case report.

Lung cancer is one of the most important and lethal cancers in the world. Human epidermal growth factor 2 (HER2) is a member of the erbB receptor tyrosine kinase family. The incidence of HER2 kinase domain mutations in adenocarcinoma of lung ranges from 1% to 3%. HER2 V659D mutation is located in the trans-membrane domain (TMD) with only a few cases reported before, and importantly, there were no more standard and effective ways for this kind of diseases until now. Afatinib irreversibly blocks all kinase-competent HER family members. Apatinib is one of the small-molecule oral anti-angiogenesis-targeted agents developed firstly in China, and it's a highly selective inhibition of the activity of VEGFR-2. This report presents an advanced lung adenocarcinoma patient with HER2 V659D mutation who was treated with combination of Afatinib and Apatinib. He achieved good efficacy and tolerable adverse reactions.

Toward stimulating apoptosis in human lung adenocarcinoma cells by novel nano-carmofur compound treatment.

Lung cancer is one of the common and most fatal diseases worldwide. It has a high incidence in both men and women, in Turkey. Current antineoplastic drugs are reported to have limitations such as narrow therapeutic index and selectivity, toxicity, and antiproliferative effects on cancer cells. Thus, this study was aimed to investigate the potential cytotoxic, antiproliferative and apoptosis-triggering effects of a newly developed SLN-Carmofur compound on human lung adenocarcinoma A549 cells. The results of this study have shown that SLN-Carmofur significantly decreased the viability of A549 cells in a dose-dependent manner by short-time application. The IC50 value of the agent caused chromatin condensation, fragmentation of the nuclei, and holes on cytoskeleton; moreover, it altered the ultrastructure of the exposed cells with clear signs of apoptosis. Taken all our results together, it is indicated that SLN-Carmofur may be proposed for further research for drug development for cancer therapy, depending on the valuable potential in stimulating apoptosis in cancer cells.

Rational Design of a Red Fluorescent Sensor for ALDH1A1 Displaying Enhanced Cellular Uptake and Reactivity.

High aldehyde dehydrogenase 1A1 (ALDH1A1) activity has emerged as a reliable marker for the identification of both normal and cancer stem cells. To facilitate the detection, molecular imaging, and sorting of stem cells, a green fluorescent probe based on the xanthene dye scaffold was recently developed. However, green dyes are less amenable to multicolor imaging because most commercial reagents are also green. Overcoming this limitation will enable the simultaneous tracking of multiple stem cell markers. Herein, we report the development of a red congener, red-AlDeSense. Through chemical tuning we were able to achieve excellent isoform selectivity and chemostability, a good turn on response, and enhanced cellular uptake and reactivity. Importantly, red-AlDeSense represents one of only a few turn-on sensors in the red region that use the d-PeT quenching mechanism. By employing red-AlDeSense and a green anti-CD44 antibody, we were able to demonstrate staining of these two stem cell markers is independent of one another in A549 lung adenocarcinoma cells.

Chemotherapy should be performed in epidermal growth factor receptor mutation-positive lung adenocarcinoma patients who had progressive disease to the first epidermal growth factor receptor-tyrosine kinase inhibitor.

After the failure of first-line epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy, some non-small cell lung cancer patients desire to receive switching with another EGFR-TKI (TKI-switching), although cytotoxic chemotherapy has been recommended as second-line therapy. It is unclear who should not receive TKI-switching in these patients. We retrospectively evaluated overall survival (OS) from the initiation of first EGFR-TKI (first-TKI) therapy in advanced lung adenocarcinoma patients with active EGFR mutations (deletion of exon 19 or L858R in exon 21) who received TKI-switching according to the best response of the first-TKI. There was no difference in the OS between patients receiving TKI-switching (n = 35) and patients receiving additional chemotherapy between the first-TKI and second-TKI therapy (n =10) (P = 0.614). Among patients receiving TKI-switching, the OS in cases with progressive disease to the first-TKI (n = 9) was shorter than that in cases with disease control to the first-TKI (n = 26) (12.7 months vs. 49.4 months, P < 0.001). Five of the nine progressive disease cases who received TKI-switching missed an opportunity to receive chemotherapy. Their OS tended to be shorter than that in patients who received chemotherapy during the whole period of anticancer therapy (12.2 months vs. 20.3 months, P = 0.060). The multivariate analysis showed that disease control to the first-TKI therapy (P = 0.005) or the presence of chemotherapy (P = 0.087) decreased the risk of mortality. Chemotherapy should be performed in patients with progressive disease to the first-TKI.

Roles of TP53 gene in the development of resistance to PI3K inhibitor resistances in CRISPR-Cas9-edited lung adenocarcinoma cells.

The mutation rates of tumor suppressor protein p53 gene (TP53) are high in lung adenocarcinoma and promote the development of acquired drug resistance. The present study evaluated the p53-dependent role in lung cancer cell sensitivity to PI3K-specific inhibitors, PI3K-associated inhibitors, PI3K-non-related inhibitors, and protein-based stimuli using designed p53 mutation. We found that the deletion of p53 key regions from amino acid 96 to 393 with the CRISPR-Cas9 altered multi-dimensional structure and sequencing of p53, probably leading the secondary changes in chemical structures and properties of PI3K subunit proteins or in interactions between p53 and PI3K isoform genes. The p53-dependent cell sensitivity varied among target specificities, drug chemical properties, mechanism-specific signal pathways, and drug efficacies, independently upon the size of molecules. The effects of the designed p53 mutation highly depend upon p53-involved molecular mechanisms in the cell. Our results indicate that lung cancer cell resistance to drug can develop with dynamic formations of p53 mutations changing the cell sensitivity. This may explain the real-time occurrence of cancer cell resistance to drug treatment, during which drugs may induce the new mutations of p53. Thus, it is important to dynamically monitor the formation of new mutations during the therapy and discover new drug resistance-specific targets.

Cytoplasmic p27Kip1 promotes tumorigenesis via suppression of RhoB activity.

The cell cycle inhibitor p27Kip1 is a tumor suppressor via the inhibition of CDK complexes in the nucleus. However, p27 also plays other functions in the cell and may acquire oncogenic roles when located in the cytoplasm. Activation of oncogenic pathways such as Ras or PI3K/AKT causes the relocalization of p27 in the cytoplasm, where it can promote tumorigenesis by unclear mechanisms. Here, we investigated how cytoplasmic p27 participates in the development of non-small cell lung carcinomas. We provide molecular and genetic evidence that the oncogenic role of p27 is mediated, at least in part, by binding to and inhibiting the GTPase RhoB, which normally acts as a tumor suppressor in the lung. Genetically modified mice revealed that RhoB expression is preferentially lost in tumors in which p27 is absent and maintained in tumors expressing wild-type p27 or p27CK- , a mutant that cannot inhibit CDKs. Moreover, although the absence of RhoB promoted tumorigenesis in p27-/- animals, it had no effect in p27CK- knock-in mice, suggesting that cytoplasmic p27 may act as an oncogene, at least in part, by inhibiting the activity of RhoB. Finally, in a cohort of lung cancer patients, we identified a subset of tumors harboring cytoplasmic p27 in which RhoB expression is maintained and these characteristics were strongly associated with decreased patient survival. Thus, monitoring p27 localization and RhoB levels in non-small cell lung carcinoma patients appears to be a powerful prognostic marker for these tumors. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

MAPK pathway activity plays a key role in PD-L1 expression of lung adenocarcinoma cells.

Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have improved the survival of patients with non-small cell lung cancer (NSCLC). Still, many patients do not respond to these inhibitors. PD-L1 (CD274) expression, one of the factors that influences the efficacy of immune checkpoint inhibitors, is dynamic. Here, we studied the regulation of PD-L1 expression in NSCLC without targetable genetic alterations in EGFR, ALK, BRAF, ROS1, MET, ERBB2 and RET. Analysis of RNA sequencing data from these NSCLCs revealed that inferred IFNγ, EGFR and MAPK signaling correlated with CD274 gene expression in lung adenocarcinoma. In a representative lung adenocarcinoma cell line panel, stimulation with EGF or IFNγ increased CD274 mRNA and PD-L1 protein and membrane levels, which were further enhanced by combining EGF and IFNγ. Similarly, tumor cell PD-L1 membrane levels increased after coculture with activated peripheral blood mononuclear cells. Inhibition of the MAPK pathway, using EGFR inhibitors cetuximab and erlotinib or the MEK 1 and 2 inhibitor selumetinib, prevented EGF- and IFNγ-induced CD274 mRNA and PD-L1 protein and membrane upregulation, but had no effect on IFNγ-induced MHC-I upregulation. Interestingly, although IFNγ increases transcriptional activity of CD274, MAPK signaling also increased stabilization of CD274 mRNA. In conclusion, MAPK pathway activity plays a key role in EGF- and IFNγ-induced PD-L1 expression in lung adenocarcinoma without targetable genetic alterations and may present a target to improve the efficacy of immunotherapy. © 2019 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Effect of FGF/FGFR pathway blocking on lung adenocarcinoma and its cancer-associated fibroblasts.

Cancer-associated fibroblasts (CAFs) are known to promote tumourigenesis through various mechanisms. Fibroblast growth factor (FGF)/FGF receptor (FGFR)-dependent lung cancers have been described. We have developed a mouse model of lung adenocarcinoma that was constructed through the induction of Fgf9 overexpression in type 2 alveolar cells. The expression of Fgf9 in adult lungs resulted in the rapid development of multiple adenocarcinoma-like tumour nodules. Here, we have characterised the contribution of CAFs and the Fgf/Fgfr signalling pathway in maintaining the lung tumours initiated by Fgf9 overexpression. We found that CAF-secreted Fgf2 contributes to tumour cell growth. CAFs overexpressed Tgfb, Mmp7, Fgf9, and Fgf2; synthesised more collagen, and secreted inflammatory cell-recruiting cytokines. CAFs also enhanced the conversion of tumour-associated macrophages (TAMs) to the tumour-supportive M2 phenotype but did not influence angiogenesis. In vivo inhibition of Fgfrs during early lung tumour development resulted in significantly smaller and fewer tumour nodules, whereas inhibition in established lung tumours caused a significant reduction in tumour size and number. Fgfr inhibition also influenced tumour stromal cells, as it significantly abolished TAM recruitment and reduced tumour vascularity. However, the withdrawal of the inhibitor caused a significant recurrence/regrowth of Fgf/Fgfr-independent lung tumours. These recurrent tumours did not possess a higher proliferative or propagative potential. Our results provide evidence that fibroblasts associated with the Fgf9-induced lung adenocarcinoma provide multiple means of support to the tumour. Although the Fgfr blocker significantly suppressed the tumour and its stromal cells, it was not sufficient to completely eliminate the tumour, probably due to the emergence of alternative (resistance/maintenance) mechanism(s). This model represents an excellent tool to further study the complex interactions between CAFs, their related chemokines, and the progression of lung adenocarcinoma; it also provides further evidence to support the need for a combinatorial strategy to treat lung cancer. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Relationship between serum tumor markers and Anaplastic Lymphoma Kinase mutations in stage IV lung adenocarcinoma in Hubei province, Central China.

OBJECTIVE: The aim of this study was to explore the predictive value of carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCCAg), and neuron-specific enolase (NSE) in the prediction of anaplastic lymphoma kinase (ALK) mutations in advance stage non-small cell lung cancer (NSCLC). SUBJECTS AND METHODS: A total of 482 cases with untreated lung adenocarcinoma were retrospectively reviewed. Finally, 72 patients with stage IV were enrolled because of intact data of the detection of ALK rearrangement and serum tumor markers, as well they have not received any previous anticancer therapy. We used the one-way ANOVA analysis, correlation analysis, and multiple logistic regression analysis to evaluate the relationship between the level of serum tumor markers and ALK mutations. RESULTS: Fifteen cases with ALK mutations and 57 cases without mutations were identified. The result of the one-way ANOVA analysis showed only CEA was significantly associated with ALK mutations (95% CI:39.05-148.88; P = .001). The area under the ROC curve (AUC) of CEA was 0.705 (95%CI:0.567-0.843; P = .015). However, no significant association was observed between CEA and ALK mutations though the result of correlation analysis (P = .069) and multivariate logistic regression analysis (OR = 0.988, 95% CI: 0.972-1.003, P = .111). CONCLUSIONS: In our study, we performed on the patients with stage IV lung adenocarcinoma in our region and found preoperative serum levels of SCCAg, CYRF21-1, and NSE not suitable for the detection of ALK mutation. Although we observed a significant association between CEA and ALK mutations; however, it was not strong enough to distinguish ALK status for the patients in our region.

IKKß Kinase Promotes Stemness, Migration, and Invasion in KRAS-Driven Lung Adenocarcinoma Cells.

KRAS oncogenic mutations are widespread in lung cancer and, because direct targeting of KRAS has proven to be challenging, KRAS-driven cancers lack effective therapies. One alternative strategy for developing KRAS targeted therapies is to identify downstream targets involved in promoting important malignant features, such as the acquisition of a cancer stem-like and metastatic phenotype. Based on previous studies showing that KRAS activates nuclear factor kappa-B (NF-κB) through inhibitor of nuclear factor kappa-B kinase ß (IKKß) to promote lung tumourigenesis, we hypothesized that inhibition of IKKß would reduce stemness, migration and invasion of KRAS-mutant human lung cancer cells. We show that KRAS-driven lung tumoursphere-derived cells exhibit stemness features and increased IKKß kinase activity. IKKß targeting by different approaches reduces the expression of stemness-associated genes, tumoursphere formation, and self-renewal, and preferentially impairs the proliferation of KRAS-driven lung tumoursphere-derived cells. Moreover, we show that IKKß targeting reduces tumour cell migration and invasion, potentially by regulating both expression and activity of matrix metalloproteinase 2 (MMP2). In conclusion, our results indicate that IKKß is an important mediator of KRAS-induced stemness and invasive features in lung cancer, and, therefore, might constitute a promising strategy to lower recurrence rates, reduce metastatic dissemination, and improve survival of lung cancer patients with KRAS-driven disease.

Loss of miR-145-5p Causes Ceruloplasmin Interference with PHD-Iron Axis and HIF-2α Stabilization in Lung Adenocarcinoma-Mediated Angiogenesis.

For decades, lung cancer has been the leading cause of cancer-related death worldwide. Hypoxia-inducible factors (HIFs) play critical roles in mediating lung cancer development and metastasis. The present study aims to clarify how HIF's over-activation affects lung cancer angiogenesis not only in a normoxic condition, but also a hypoxic niche. Our study shows that human lung cancer exhibits elevated levels of ceruloplasmin (CP), which has a negative impact on the prognosis of patients. CP affects the cellular Fe2+ level, which inactivates prolyl hydroxylase (PHD) 1 and 2, resulting in HIF-2α enhancement. Increased HIF-2α leads to vascular endothelial growth factor-A (VEGF-A) secretion and angiogenesis. The expression of CP is under the epigenetic control of miR-145-5p. Restoration of miR-145-5p by miRNA mimics transfection decreases CP expression, increases Fe2+ and PHD1/2 levels and HIF hydroxylation while reduced HIF-2α levels resulting in the inhibition of tumor angiogenesis. In contrast, inhibition of miR-145-5p by miRNA inhibitors increases the expression of CP and VEGF-A in lung cancer cells. Significantly, miR-145-5p expression is lost in the tumor samples of lung cancer patients, and low miR-145-5p expression is strongly correlated with a shorter overall survival time. In conclusion, the current study reveals the clinical importance and prognostic value of miR-145-5p and CP. It identifies a unique mechanism of HIF-2α over-activation, which is mediated by iron imbalance of the iron-PHD coupling that modulates tumor angiogenesis.

EGFR-targeted therapy alters the tumor microenvironment in EGFR-driven lung tumors: Implications for combination therapies.

Immune checkpoint inhibitors targeting the programmed cell death receptor/ligand 1 (PD-1/PD-L1) pathway have profoundly improved the clinical management of non-small-cell lung cancer (NSCLC). Nevertheless, the superiority of single-agent PD-1/PD-L1 inhibitors in pretreated EGFR mutant patients has turned out to be moderate. One proposed mechanism for poor response to immune checkpoint inhibitors is an immunosuppressive tumor microenvironment. Therefore, we utilized two autochthonous EGFR-driven lung tumor models to investigate dynamic microenvironmental responses to EGFR-TKI treatment. We observed that at an early stage, sensitive EGFR-TKIs caused obvious tumor shrinkage accompanied by increased cytotoxic CD8+ T cells and dendritic cells, eradication of Foxp3+ Tregs, and inhibition of M2-like polarization of macrophages. However, the tumor microenvironmental changes that may be most beneficial for combination treatment with immune-mediated anticancer approaches were only temporary and disappeared as treatment continued. Meanwhile, the level of myeloid-derived suppressor cells (MDSCs), particularly mononuclear MDSCs, was consistently elevated throughout the treatment. Analysis of inflammatory factors in serum showed that EGFR-TKIs increased the levels of IL-10 and CCL-2. Our study systematically analyzed dynamic changes in tumor microenvironments responding to EGFR-TKIs in vivo. The results have implications for combination therapy using EGFR-TKIs. The optimal sequence of the treatment and strategies that modulate the tumor microenvironment to a state that may favor antitumor immune responses need to be considered when designing clinical trials.

Three-dimensional nanostructured substrates enable dynamic detection of ALK-rearrangement in circulating tumor cells from treatment-naive patients with stage III/IV lung adenocarcinoma.

BACKGROUND: Circulating tumor cells (CTC) shows great prospect to realize precision medicine in cancer patients. METHODS: We developed the NanoVelcro Chip integrating three functional mechanisms. NanoVelcro CTC capture efficiency was tested in stage III or IV lung adenocarcinoma. Further, ALK-rearrangement status was examined through fluorescent in situ hybridization in CTCs enriched by NanoVelcro. RESULTS: NanoVelcro system showed higher CTC-capture efficiency than CellSearch in stage III or IV lung adenocarcinoma. CTC counts obtained by both methods were positively correlated (r = 0.45, p < 0.05). Further, Correlation between CTC counts and pTNM stage determined by NanoVelcro was more significant than that determined by CellSearch (p < 0.001 VS p = 0.029). All ALK-positive patients had 3 or more ALK-rearranged CTC per ml of blood. Less than 3 ALK-rearranged CTC was detected in ALK-negative patients. NanoVelcro can detect the ALK-rearranged status with consistent sensitivity and specificity compared to biopsy test. Furthermore, the ALK-rearranged CTC ratio correlated to the pTNM stage in ALK-positive patients. Following up showed that CTCs counting by NanoVelcro was more stable and reliable in evaluating the efficacy of Clozotinib both in the short and long run compared with CellSearch. Changing of NanoVlecro CTC counts could accurately reflect disease progression. CONCLUSION: NanoVelcro provides a sensitive method for CTC counts and characterization in advanced NSCLC. ALK-rearrangement can be detected in CTCs collected from advanced NSCLC patients by NanoVelcro, facilitating diagnostic test and prognosis analysis, most importantly offering one noninvasive method for real-time monitoring of treatment reaction.

Inhibition of secretory phospholipase A2 IIa attenuates prostaglandin E2-induced invasiveness in lung adenocarcinoma.

Secretory phospholipase A2 IIa (sPLA2 IIa) catalyzes the production of multiple inflammatory mediators that influence the development of lung and other cancers. The most potent of these carcinogenic mediators is prostaglandin E2 (PGE2). We hypothesize that sPLA2 IIa inhibition modulates the production of PGE2, and sPLA2 IIa inhibition exerts its antineoplastic effects via downregulation of PGE2 production. We aim to evaluate these relationships via analysis of PGE2-mediated growth regulation pathways. A549 and H1650 lung adenocarcinoma cells were assayed for PGE2 production in the presence of sPLA2 IIa inhibitor. A549 and H1650 cells were treated with PGE2 and immune blotting was performed to assess ICAM-1 expression and STAT-3 activity. PGE2-induced ICAM-1 expression was measured via immunofluorescence. A549 and H1650 cells were treated with PGE2 in the presence of STAT3 inhibitor and assayed for ICAM-1 expression. A549 cells were treated with PGE2 in the presence ICAM-1 blocking antibody and assayed for invasion. PGE2 stimulation significantly increased the invasiveness and proliferation of lung adenocarcinoma (invasion p < 0.05, proliferation p < 0.05 A549 cells, p < 0.005 H1650 cells). sPLA2 IIa inhibition reduced PGE2 secretion (p < 0.05). PGE2 stimulation significantly upregulated the expression of cell adhesion molecule ICAM-1 and the phosphorylation of anti-apoptotic transcription factor STAT3 (p < 0.05). STAT3 inhibition attenuated ICAM-1 expression demonstrating the dependence of ICAM-1 on the STAT3 pathway (p < 0.05). ICAM-1 blockade attenuated the pro-invasive effects of PGE2 (p < 0.05). sPLA2 IIa inhibition attenuates the potent effects of PGE2-induced invasiveness. This is mediated by decreasing pro-inflammatory and invasion-promoting ICAM-1via the STAT-3 pathway. These data further describe how sPLA2 IIa inhibition mechanistically exerts its anticancer effects and support its use as an antineoplastic agent.

miR-186-5p promotes cell growth, migration and invasion of lung adenocarcinoma by targeting PTEN.

OBJECTIVE: To explore the expression of miR-186-5p in lung adenocarcinoma (LUAD) and its possible function associated with cancer cell proliferation, migration and invasion. METHODS: MiR-186-5p expression levels in LUAD samples, human LUAD cell lines H1299 and NCI-H1975, and normal human lung epithelial cell line BEAS-IB were assessed by quantitative real-time PCR (qRT-PCR). H1299 and NCI-H1975 cells were transfected with miR-186-5p mimic or miRNA negative control. CCK-8 assay was performed to evaluate the cell proliferation. Transwell assay and transwell-matrigel™ invasion assay were applied to assess the migration and invasion abilities of H1299 and NCI-H1975 cells. RESULTS: miR-186-5p expression was significantly up-regulated in LUAD tumor tissues and LUAD cell lines as compared with tumor-adjacent tissues and normal human lung epithelial cells, respectively. MiR-186-5p overexpression remarkably promoted the proliferation, migration and invasion of LUAD cells. Furthermore, phosphatase and tensin homolog (PTEN) was a direct target of miR-186-5p verified by luciferase reporter assay. Overexpression of PTEN significantly suppressed LUAD cells to proliferate, migrate and invade. MiR-186-5p overexpression-induced LUAD cell phenotype could be partially rescued by co-overexpression of miR-186-5p and PTEN. CONCLUSION: This study demonstrated that miR-186-5p is up-regulated in LUAD, and functionally associated with cell proliferation, migration and invasion. MiR-186-5p promotes the proliferation, migration and invasion of LUAD cells by targeting PTEN. MiR-186-5p may be utilized as a novel molecular marker and therapeutic target of LUAD.

Role of Dusp6 Phosphatase as a Tumor Suppressor in Non-Small Cell Lung Cancer.

DUSP6/MKP3 is a dual-specific phosphatase that regulates extracellular regulated kinase ERK1/2 and ERK5 activity, with an increasingly recognized role as tumor suppressor. In silico studies from Gene expression Omnibus (GEO) and Cancer Genome atlas (TCGA) databases reveal poor prognosis in those Non-small cell lung cancer (NSCLC) patients with low expression levels of DUSP6. In agreement with these data, here we show that DUSP6 plays a major role in the regulation of cell migration, motility and tumor growth. We have found upregulation in the expression of several genes involved in epithelial to mesenchymal transition (EMT) in NSCLC-DUSP6 depleted cells. Data obtained in RNA-seq studies carried out in DUSP6 depleted cells identified EGFR, TGF-ß and WNT signaling pathways and several genes such as VAV3, RUNXR2, LEF1, FGFR2 whose expression is upregulated in these cells and therefore affecting cellular functions such as integrin mediated cell adhesion, focal adhesion and motility. Furthermore, EGF signaling pathway is activated via ERK5 and not ERK1/2 and TGF-ß via SMAD2/3 in DUSP6 depleted cells. In summary DUSP6 is a tumor suppressor in NSCLC and re-establishment of its expression may be a potential strategy to revert poor outcome in NSCLC patients.