Roflumilast inhibits tumor growth and migration in STK11/LKB1 deficient pancreatic cancer

Pancreatic cancer is a malignant tumor of the digestive system. It is highly aggressive, easily metastasizes, and extremely difficult to treat. This study aimed to analyze the genes that might regulate pancreatic cancer migration to provide an essential basis for the prognostic assessment of pancreatic cancer and individualized treatment. A CRISPR knockout library directed against 915 murine genes was transfected into TB 32047 cell line to screen which gene loss promoted cell migration. Next-generation sequencing and PinAPL.py- analysis was performed to identify candidate genes. We then assessed the effect of serine/threonine kinase 11 (STK11) knockout on pancreatic cancer by wound-healing assay, chick agnosia (CAM) assay, and orthotopic mouse pancreatic cancer model. We performed RNA sequence and Western blotting for mechanistic studies to identify and verify the pathways. After accelerated Transwell migration screening, STK11 was identified as one of the top candidate genes. Further experiments showed that targeted knockout of STK11 promoted the cell migration and increased liver metastasis in mice. Mechanistic analyses revealed that STK11 knockout influences blood vessel morphogenesis and is closely associated with the enhanced expression of phosphodiesterases (PDEs), especially PDE4D, PDE4B, and PDE10A. PDE4 inhibitor Roflumilast inhibited STK11-KO cell migration and tumor size, further demonstrating that PDEs are essential for STK11-deficient cell migration. Our findings support the adoption of therapeutic strategies, including Roflumilast, for patients with STK11-mutated pancreatic cancer in order to improve treatment efficacy and ultimately prolong survival.

Propionate reinforces epithelial identity and reduces aggressiveness of lung carcinoma

The epithelial-to-mesenchymal transition (EMT) plays a central role in the development of cancer metastasis and resistance to chemotherapy. However, its pharmacological treatment remains challenging. Here, we used an EMT-focused integrative functional genomic approach and identified an inverse association between short-chain fatty acids (propionate and butanoate) and EMT in non-small cell lung cancer (NSCLC) patients. Remarkably, treatment with propionate in vitro reinforced the epithelial transcriptional program promoting cell-to-cell contact and cell adhesion, while reducing the aggressive and chemo-resistant EMT phenotype in lung cancer cell lines. Propionate treatment also decreased the metastatic potential and limited lymph node spread in both nude mice and a genetic NSCLC mouse model. Further analysis revealed that chromatin remodeling through H3K27 acetylation (mediated by p300) is the mechanism underlying the shift toward an epithelial state upon propionate treatment. The results suggest that propionate administration has therapeutic potential in reducing NSCLC aggressiveness and warrants further clinical testing.

The EMT transcription factor ZEB1 governs a fitness-promoting but vulnerable DNA replication stress response

The DNA damage response (DDR) and epithelial-to-mesenchymal transition (EMT) are two crucial cellular programs in cancer biology. While the DDR orchestrates cell-cycle progression, DNA repair, and cell death, EMT promotes invasiveness, cellular plasticity, and intratumor heterogeneity. Therapeutic targeting of EMT transcription factors, such as ZEB1, remains challenging, but tumor-promoting DDR alterations elicit specific vulnerabilities. Using multi-omics, inhibitors, and high-content microscopy, we discover a chemoresistant ZEB1-high-expressing sub-population (ZEB1^hi) with co-rewired cell-cycle progression and proficient DDR across tumor entities. ZEB1 stimulates accelerated S-phase entry via CDK6, inflicting endogenous DNA replication stress. However, DDR buildups involving constitutive MRE11-dependent fork resection allow homeostatic cycling and enrichment of ZEB1^hi cells during transforming growth factor β (TGF-β)-induced EMT and chemotherapy. Thus, ZEB1 promotes G1/S transition to launch a progressive DDR benefitting stress tolerance, which concurrently manifests a targetable vulnerability in chemoresistant ZEB1^hi cells. Our study thus highlights the translationally relevant intercept of the DDR and EMT.

3D hydrogel-based microcapsules as an in vitro model to study tumorigenicity, cell migration and drug resistance

In this work, we analyzed the reliability of alginate-gelatin microcapsules as artificial tumor model. These tumor-like scaffolds are characterized by their composition and stiffness (∼25 kPa), and their capability to restrict -but not hinder- cell migration, proliferation and release from confinement. Hydrogel-based microcapsules were initially utilized to detect differences in mechano-sensitivity between MCF7 and MDA-MB-231 breast cancer cells, and the endothelial cell line EA.hy926. Additionally, we used RNA-seq and transcriptomic methods to determine how the culture strategy (i.e. 2D v/s 3D) may pre-set the expression of genes involved in multidrug resistance, being then validated by performing cytotoxicological tests and assays of cell morphology. Our results show that both breast cancer cells can generate elongated multicellular spheroids inside the microcapsules, prior being released (mimicking intravasation stages), a behavior which was not observed in endothelial cells. Further, we demonstrate that cells isolated from 3D scaffolds show resistance to cisplatin, a process which seems to be strongly influenced by mechanical stress, instead of hypoxia. We finally discuss the role played by aneuploidy in malignancy and resistance to anticancer drugs, based on the increased number of polynucleated cells found within these microcapsules. Overall, our outcomes demonstrate that alginate-gelatin microcapsules represent a simple, yet very accurate tumor-like model, enabling us to mimic the most relevant malignant hints described in vivo, suggesting that confinement and mechanical stress need to be considered when studying pathogenicity and drug resistance of cancer cells in vitro. STATEMENT OF SIGNIFICANCE: In this work, we analyzed the reliability of alginate-gelatin microcapsules as an artificial tumor model. These scaffolds are characterized by their composition, elastic properties, and their ability to restrict cell migration, proliferation, and release from confinement. Our results demonstrate four novel outcomes: (i) studying cell migration and proliferation in 3D enabled discrimination between malignant and non-pathogenic cells, (ii) studying the cell morphology of cancer aggregates entrapped in alginate-gelatin microcapsules enabled determination of malignancy degree in vitro, (iii) determination that confinement and mechanical stress, instead of hypoxia, are required to generate clones resistant to anticancer drugs (i.e. cisplatin), and (iv) evidence that resistance to anticancer drugs could be due to the presence of polynucleated cells localized inside polymer-based artificial tumors.

Metabolic impairment of non-small cell lung cancers by mitochondrial HSPD1 targeting

Background

The identification of novel targets is of paramount importance to develop more effective drugs and improve the treatment of non-small cell lung cancer (NSCLC), the leading cause of cancer-related deaths worldwide. Since cells alter their metabolic rewiring during tumorigenesis and along cancer progression, targeting key metabolic players and metabolism-associated proteins represents a valuable approach with a high therapeutic potential. Metabolic fitness relies on the functionality of heat shock proteins (HSPs), molecular chaperones that facilitate the correct folding of metabolism enzymes and their assembly in macromolecular structures.

Methods

Gene fitness was determined by bioinformatics analysis from available datasets from genetic screenings. HSPD1 expression was evaluated by immunohistochemistry from formalin-fixed paraffin-embedded tissues from NSCLC patients. Real-time proliferation assays with and without cytotoxicity reagents, colony formation assays and cell cycle analyses were used to monitor growth and drug sensitivity of different NSCLC cells in vitro. In vivo growth was monitored with subcutaneous injections in immune-deficient mice. Cell metabolic activity was analyzed through extracellular metabolic flux analysis. Specific knockouts were introduced by CRISPR/Cas9.

Results

We show heat shock protein family D member 1 (HSPD1 or HSP60) as a survival gene ubiquitously expressed in NSCLC and associated with poor patients’ prognosis. HSPD1 knockdown or its chemical disruption by the small molecule KHS101 induces a drastic breakdown of oxidative phosphorylation, and suppresses cell proliferation both in vitro and in vivo. By combining drug profiling with transcriptomics and through a whole-genome CRISPR/Cas9 screen, we demonstrate that HSPD1-targeted anti-cancer effects are dependent on oxidative phosphorylation and validated molecular determinants of KHS101 sensitivity, in particular, the creatine-transporter SLC6A8 and the subunit of the cytochrome c oxidase complex COX5B.

Conclusions

These results highlight mitochondrial metabolism as an attractive target and HSPD1 as a potential theranostic marker for developing therapies to combat NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02049-8.

POS0423 NCOA3 AMPLIFIES PROFIBROTIC TRANSCRIPTIONAL PROGRAMS IN SYSTEMIC SCLEROSIS

Background:

Excessive activation of fibroblasts with a TGFβ-biased gene signature and deposition of extracellular matrix are key features of fibrotic diseases. The mechanisms underlying these transcriptional changes remain poorly understood. Deregulation, mutations and malfunctions of transcriptional co-regulators, which can interact with multiple transcription factors and enable a broad-spectrum regulation of transcriptional networks, have been implicated as driving factors in a large number of diseases and pathologies.

Objectives:

In the present study, we aimed to analyze the role of the co-regulator Nuclear Receptor Co-Activator 3 (NCOA3) in fibroblast activation and tissue fibrosis, and to evaluate a potential interaction of NCOA3 with fibrosis-relevant transcription factors.

Methods:

NCOA3 was inhibited genetically by siRNA transfection and pharmacologically by the SRC3 inhibitor-2 (SI-2). We performed bulk RNASeq of human dermal fibroblasts and in silico transcription factor binding site screening of differentially expressed genes (DEGs). The interaction of NCOA3 and TGFβ-SMAD signaling was analyzed by reporter and CoIP assays.

Results:

The expression of NCOA3 in skin biopsies of SSc patients compared to normal controls demonstrated that SSc fibroblasts express modestly, but significantly reduced levels of NCOA3, which persisted in cultured SSc fibroblasts. Stimulation of normal fibroblasts with chronically high levels of TGFβ as they also occur in fibrotic tissue remodeling strongly decreased NCOA3 expression to a similar extent as in SSc fibroblasts. Furthermore, NCOA3 expression is also deregulated in different murine models of skin fibrosis. To investigate the functional effects of decreased NCOA3 levels, we targeted the expression of NCOA3 in normal fibroblasts. SiRNA-mediated knockdown of NCOA3 ameliorated TGFβ-induced gene expression, collagen release, myofibroblast differentiation and cell proliferation. In contrast, knockdown of NCOA3 had no effects on collagen release, expression of contractile proteins or gene expression in unstimulated fibroblasts, suggesting that NCOA3 is not required for cellular homeostasis. To characterize the molecular mechanisms, we performed RNASeq upon NCOA3 knockdown. We identified 343 significant differentially expressed genes (220 downregulated and 123 upregulated with a Benjamini-Hochberg false discovery rate FDR < 0.25 and fold change > 1.5) between TGFβ-stimulated fibroblasts with and without NCOA3 knockdown (NCOA3-DEGs) including the fibrosis-relevant genes EDNRB, COL5A3, HES1, IL11 or IL33. Functional analysis of the NCOA3-DEGs showed enrichment of pathway terms such as collagen binding and extracellular matrix organization. In silico screening of the promoters of the NCOA3-DEGs for potential transcription factor binding motifs revealed binding motifs of core transcription factors of fibroblast activation and tissue fibrosis such as SMAD2/3/4, RBPJ, ZEB1, TCF4, REL, and SNAIL2 amongst the downregulated NCOA3-DEGs. Experimental validation of our biostatistical results using SMAD3 as example demonstrated a higher percentage of NCOA3-pSMAD3 double-positive fibroblasts in skin sections of SSc patients compared to healthy controls. In addition, knockdown of NCOA3 reduced TGFβ-induced SMAD-reporter activity. Furthermore, stimulation with TGFβ increased the interaction of NCOA3 with SMAD3 as analyzed by co-immunoprecipitation. Simultaneous knockdown of NCOA3 and SMAD3 showed no additional reductions compared to the single knockdowns, suggesting that NCOA3 controls SMAD3-dependent gene transcription under fibrotic conditions. Finally, inhibition of NCOA3 showed anti-fibrotic effects in different murine models of experimental skin and lung fibrosis.

Conclusion:

Our findings characterize NCOA3 as regulator of multiple pro-fibrotic transcription programs. Pharmaceutical inhibition of NCOA3 might be a strategy to interfere simultaneously with several core pro-fibrotic mediators in fibrotic diseases such as SSc.

Acknowledgements:

We thank Lena Summa, Vladyslav Fedorchenko, Wolfgang Espach and Regina Kleinlein for excellent technical assistance.

The study was funded by grants DI 1537/7-1, DI 1537/8-1, DI 1537/9-1 and -2, DI 1537/11-1, DI 1537/12-1, DI 1537/13-1, DI 1537/14-1, DI 1537/17-1, DE 2414/2-1, DE 2414/4-1, and RA 2506/3-1 of the German Research Foundation, SFB CRC1181 (project C01) and SFB TR221/ project number 324392634 (B04) of the German Research Foundation, grants J39, J40 and A64 of the IZKF in Erlangen, grant 2013.056.1 of the Wilhelm-Sander-Foundation, grants 2014_A47, 2014_A248 and 2014_A184 of the Else-Kröner-Fresenius-Foundation, grant 14-12-17-1-Bergmann of the ELAN-Foundation Erlangen, BMBF (Era-Net grant 01KT1801), MASCARA program, TP 2 and a Career Support Award of Medicine of the Ernst Jung Foundation.

Disclosure of Interests:

Clara Dees: None declared, Sebastian Poetter: None declared, Maximilian Fuchs: None declared, Christina Bergmann: None declared, Alexandru-Emil Matei: None declared, Andrea-Hermina Györfi: None declared, Alina Soare: None declared, Andreas Ramming: None declared, Paolo Ceppi: None declared, Georg Schett: None declared, Meik Kunz: None declared, Jörg H.W. Distler Consultant of: Actelion, Active Biotech, Anamar, ARXX, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GSK, Inventiva, JB Therapeutics, Medac, Pfizer, RuiYi and UCB, Grant/research support from: Anamar, Active Biotech, Array Biopharma, ARXX, aTyr, BMS, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GSK, Inventiva, Novartis, Sanofi-Aventis, RedX, UCB

Down-Regulation of CK2α Leads toUp-Regulation of the Cyclin-Dependent Kinase Inhibitor p27KIP1 in Conditions Unfavorable for the Growth of Myoblast Cells

BACKGROUND/AIMS

Compelling evidence indicates that CK2α, which is one of the two catalytic isoforms of protein kinase CK2, is required for cell viability and plays an important role in cell proliferation and differentiation. While much is known on CK2 in the context of disease states, particularly cancer, its critical role in non-cancerous cell growth has not been extensively investigated.

METHODS

In the present study, we have employed a cell line derived from rat heart with inducible down-regulation of CK2α and CK2α-knockout mouse tissue to identify CK2-mediated molecular mechanisms regulating cell growth. For this, we have performed Incucyte® live-cell analysis and applied flow cytometry, western blot, immunoprecipitation, immunohistochemistry, RT-qPCR and luciferase-based methods.

RESULTS

Here, we show that lack of CK2α results in significantly delayed cell cycle progression through G1, inhibition of cyclin E-CDK2 complex, decreased phosphorylation of Rb protein at S795, and inactivation of E2F transcription factor. These events are accompanied by nuclear accumulation and up-regulation of the cyclin-dependent kinase inhibitor p27^KIP1 in cells and CK2α-knockout mouse tissues. We found that increased levels of p27^KIP1 are mainly attributable to post-translational modifications, namely phosphorylation at S10 and T197 amino acid residues catalyzed by Dyrk1B and AMPK, respectively, as silencing of FoxO3A transcription factor, which activates CDKN1B the gene coding for p27^KIP1, does not result in markedly decreased expression levels of the corresponding protein. Interestingly, simultaneous silencing of CK2α and p27^KIP1 significantly impairs cell cycle progression without increasing cell death.

CONCLUSION

Taken together, our study sheds light on the molecular mechanisms controlling cell cycle progression through G1 phase when myoblasts proliferation potential is impaired by CK2α depletion. Our results suggest that elevated levels of p27^KIP1, which follows CK2α depletion, contribute to delay the G1-to-S phase transition. Effects seen when p27^KIP1 is down-regulated are independent of CK2α and reflect the protective role exerted by p27^KIP1 under unfavorable cell growth conditions.

3D Spheroids Versus 3D Tumor-Like Microcapsules: Confinement and Mechanical Stress May Lead to the Expression of Malignant Responses in Cancer Cells

As 2D surfaces fail to resemble the tumoral milieu, current discussions are focused on which 3D cell culture strategy may better lead the cells to express in vitro most of the malignant hints described in vivo. In this study, this question is assessed by analyzing the full genetic profile of MCF7 cells cultured either as 3D spheroids-considered as "gold standard" for in vitro cancer research- or immobilized in 3D tumor-like microcapsules, by RNA-Seq and transcriptomic methods, allowing to discriminate at big-data scale, which in vitro strategy can better resemble most of the malignant features described in neoplastic diseases. The results clearly show that mechanical stress, rather than 3D morphology only, stimulates most of the biological processes involved in cancer pathogenicity, such as cytoskeletal organization, migration, and stemness. Furthermore, cells entrapped in hydrogel-based scaffolds are likely expressing other physiological hints described in malignancy, such as the upregulated expression of metalloproteinases or the resistance to anticancer drugs, among others. According to the knowledge, this study represents the first attempt to answer which 3D experimental system can better mimic the neoplastic architecture in vitro, emphasizing the relevance of confinement in cancer pathogenicity, which can be easily achieved by using hydrogel-based matrices.

The role of miR-200b/c in balancing EMT and proliferation revealed by an activity reporter

Since their discovery, microRNAs (miRNAs) have been widely studied in almost every aspect of biology and medicine, leading to the identification of important gene regulation circuits and cellular mechanisms. However, investigations are generally focused on the analysis of their downstream targets and biological functions in overexpression and knockdown approaches, while miRNAs endogenous levels and activity remain poorly understood. Here, we used the cellular plasticity-regulating process of epithelial-to-mesenchymal transition (EMT) as a model to show the efficacy of a fluorescent sensor to separate cells with distinct EMT signatures, based on miR-200b/c activity. The system was further combined with a CRISPR-Cas9 screening platform to unbiasedly identify miR-200b/c upstream regulating genes. The sensor allows to infer miRNAs fundamental biological properties, as profiling of sorted cells indicated miR-200b/c as a molecular switch between EMT differentiation and proliferation, and suggested a role for metabolic enzymes in miR-200/EMT regulation. Analysis of miRNAs endogenous levels and activity for in vitro and in vivo applications could lead to a better understanding of their biological role in physiology and disease.

Thymidylate synthase drives the phenotypes of epithelial-to-mesenchymal transition in non-small cell lung cancer

Background

Epithelial-to-mesenchymal transition (EMT) enhances motility, stemness, chemoresistance and metastasis. Little is known about how various pathways coordinate to elicit EMT’s different functional aspects in non-small cell lung cancer (NSCLC). Thymidylate synthase (TS) has been previously correlated with EMT transcription factor ZEB1 in NSCLC and imparts resistance against anti-folate chemotherapy. In this study, we establish a functional correlation between TS, EMT, chemotherapy and metastasis and propose a network for TS mediated EMT.

Methods

Published datasets were analysed to evaluate the significance of TS in NSCLC fitness and prognosis. Promoter reporter assay was used to sort NSCLC cell lines in TS^HIGH and TS^LOW. Metastasis was assayed in a syngeneic mouse model.

Results

TS levels were prognostic and predicted chemotherapy response. Cell lines with higher TS promoter activity were more mesenchymal-like. RNA-seq identified EMT as one of the most differentially regulated pathways in connection to TS expression. EMT transcription factors HOXC6 and HMGA2 were identified as upstream regulator of TS, and AXL, SPARC and FOSL1 as downstream effectors. TS knock-down reduced the metastatic colonisation in vivo.

Conclusion

These results establish TS as a theranostic NSCLC marker integrating survival, chemo-resistance and EMT, and identifies a regulatory network that could be targeted in EMT-driven NSCLC.

Targeting EMT in Cancer with Repurposed Metabolic Inhibitors

Epithelial-to-mesenchymal transition (EMT) determines the most lethal features of cancer, metastasis formation and chemoresistance, and therefore represents an attractive target in oncology. However, direct targeting of EMT effector molecules is, in most cases, pharmacologically challenging. Since emerging research has highlighted the distinct metabolic circuits involved in EMT, we propose the use of metabolism-specific inhibitors, FDA approved or under clinical trials, as a drug repurposing approach to target EMT in cancer. Metabolism-inhibiting drugs could be coupled with standard chemo- or immunotherapy to combat EMT-driven resistant and aggressive cancers.

Characterization and diagnostic application of genomic NPM-ALK fusion sequences in anaplastic large-cell lymphoma

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion genes resulting from the translocation t(2;5)(p23;q35) are present in almost 90% of childhood ALK-positive anaplastic large-cell lymphomas (ALCL). Detection and quantification of minimal disseminated disease (MDD) by measuring NPM-ALK fusion transcript levels in the blood provide independent prognostic parameters. Characterization of the genomic breakpoints provides insights into the pathogenesis of the translocation and allows for DNA-based minimal disease monitoring.

We designed a nested multiplex PCR assay for identification and characterization of genomic NPM-ALK fusion sequences in 45 pediatric ALCL-patients, and used the sequences for quantitative MDD monitoring. Breakpoint analysis indicates the involvement of inaccurate non-homologous end joining repair mechanisms in the formation of NPM-ALK fusions. Parallel quantification of RNA and DNA levels in the cellular fraction of 45 blood samples from eight patients with NPM-ALK-positive ALCL correlated, as did cell-free circulating NPM-ALK DNA copies in the plasma fraction of 37 blood samples. With genomic NPM-ALK fusion sequence quantification, plasma samples of ALCL patients become an additional source for MRD-assessment. Parallel quantification of NPM-ALK transcripts and fusion genes in ALCL cell lines treated with the ALK kinase inhibitor crizotinib illustrates the potential value of supplementary DNA-based quantification in particular clinical settings.

Polyol Pathway Links Glucose Metabolism to the Aggressiveness of Cancer Cells

Cancer cells alter their metabolism to support their malignant properties. In this study, we report that the glucose-transforming polyol pathway (PP) gene aldo-keto-reductase-1-member-B1 (AKR1B1) strongly correlates with epithelial-to-mesenchymal transition (EMT). This association was confirmed in samples from lung cancer patients and from an EMT-driven colon cancer mouse model with p53 deletion. In vitro, mesenchymal-like cancer cells showed increased AKR1B1 levels, and AKR1B1 knockdown was sufficient to revert EMT. An equivalent level of EMT suppression was measured by targeting the downstream enzyme sorbitol-dehydrogenase (SORD), further pointing at the involvement of the PP. Comparative RNA sequencing confirmed a profound alteration of EMT in PP-deficient cells, revealing a strong repression of TGFβ signature genes. Excess glucose was found to promote EMT through autocrine TGFβ stimulation, while PP-deficient cells were refractory to glucose-induced EMT. These data show that PP represents a molecular link between glucose metabolism, cancer differentiation, and aggressiveness, and may serve as a novel therapeutic target.Significance: A glucose-transforming pathway in TGFβ-driven epithelial-to-mesenchymal transition provides novel mechanistic insights into the metabolic control of cancer differentiation. Cancer Res; 78(7); 1604-18. ©2018 AACR.

GNA13 expression promotes drug resistance and tumor-initiating phenotypes in squamous cell cancers

Treatment failure in solid tumors occurs due to the survival of specific subpopulations of cells that possess tumor-initiating (TIC) phenotypes. Studies have implicated G protein-coupled-receptors (GPCRs) in cancer progression and the acquisition of TIC phenotypes. Many of the implicated GPCRs signal through the G protein GNA13. In this study, we demonstrate that GNA13 is upregulated in many solid tumors and impacts survival and metastases in patients. GNA13 levels modulate drug resistance and TIC-like phenotypes in patient-derived head and neck squamous cell carcinoma (HNSCC) cells in vitro and in vivo. Blockade of GNA13 expression, or of select downstream pathways, using small-molecule inhibitors abrogates GNA13-induced TIC phenotypes, rendering cells vulnerable to standard-of-care cytotoxic therapies. Taken together, these data indicate that GNA13 expression is a potential prognostic biomarker for tumor progression, and that interfering with GNA13-induced signaling provides a novel strategy to block TICs and drug resistance in HNSCCs.

CD95/Fas Increases Stemness in Cancer Cells by Inducing a STAT1-Dependent Type I Interferon Response

Stimulation of CD95/Fas drives and maintains cancer stem cells (CSCs). We now report that this involves activation of signal transducer and activator of transcription 1 (STAT1) and induction of STAT1-regulated genes and that this process is inhibited by active caspases. STAT1 is enriched in CSCs in cancer cell lines, patient-derived human breast cancer, and CD95^high-expressing glioblastoma neurospheres. CD95 stimulation of cancer cells induced secretion of type I interferons (IFNs) that bind to type I IFN receptors, resulting in activation of Janus-activated kinases, activation of STAT1, and induction of a number of STAT1-regulated genes that are part of a gene signature recently linked to therapy resistance in five primary human cancers. Consequently, we identified type I IFNs as drivers of cancer stemness. Knockdown or knockout of STAT1 resulted in a strongly reduced ability of CD95L or type I IFN to increase cancer stemness. This identifies STAT1 as a key regulator of the CSC-inducing activity of CD95.

Thymidylate synthase is functionally associated with ZEB1 and contributes to the epithelial-to-mesenchymal transition of cancer cells

Thymidylate synthase (TS) is a fundamental enzyme of nucleotide metabolism and one of the oldest anti-cancer targets. Beginning from the analysis of gene array data from the NCI-60 panel of cancer cell lines, we identified a significant correlation at both gene and protein level between TS and the markers of epithelial-to-mesenchymal transition (EMT), a developmental process that allows cancer cells to acquire features of aggressiveness, like motility and chemoresistance. TS levels were found to be significantly augmented in mesenchymal-like compared to epithelial-like cancer cells, to be regulated by EMT induction, and to negatively correlate with micro-RNAs (miRNAs) usually expressed in epithelial-like cells and known to actively suppress EMT. Transfection of EMT-suppressing miRNAs reduced TS levels, and a specific role for miR-375 in targeting the TS 3'-untranslated region was identified. A particularly relevant association was found between TS and the powerful EMT driver ZEB1, the shRNA-mediated knockdown of which up-regulated miR-375 and reduced TS cellular levels. The TS-ZEB1 association was confirmed in clinical specimens from lung tumours and in a genetic mouse model of pancreatic cancer with ZEB1 deletion. Interestingly, TS itself appeared to have a regulatory role in EMT in cancer cells, as TS knockdown could directly reduce the EMT phenotype, the migratory ability of cells, the expression of stem-like markers, and chemoresistance. Taken together, these data indicate that the TS enzyme is functionally linked with EMT and cancer differentiation, with several potential translational implications. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract 450: Aldo-keto reductase family 1 member b1 links glucose metabolism to epithelial-to-mesenchymal transition

Introduction: We performed a bioinformatic analysis to identify metabolic genes connected with the process of epithelial-to-mesenchymal-transition (EMT) and the results indicated a possible role for aldo-keto reductase family 1 member B1 (AKR1B1). AKR1B1 is a member of the polyol pathway responsible for catalyzing the reduction of numerous aldehydes, such as glucose. Based on the importance of EMT during carcinogenesis and metastatic progression and on the relevance of enhanced glycolytic rate in cancer cells, we investigated a direct role for AKR1B1 during EMT and tumor progression.

Experimental Procedure: The bioinformatic analysis was performed on datasets from the NCI60 panel of cancer cell lines. Cancer cells from lung, breast and ovarian origin have been investigated in vitro: changes in EMT markers were monitored by western blotting as well as immunofluorescence, growth assays were performed using the IncuCyte® ZOOM, migration rate was tested by wound-healing assays. Changes in stem-like properties were determined by western blotting, FACS and sphere-formation assays. Immunohistochemistry (IHC) was performed on FFPE specimens from lung cancer patients. Additionally, IHC was performed on samples from a mouse model of AOM-induced colon tumorigenesis in mice with an intestinal epithelial cell-specific p53 deletion (which were shown to undergo EMT) and in the wildtype counterparts.

Results: AKR1B1 gene and protein expression was found significantly higher (7-fold) in mesenchymal-like cells. ShRNA-mediated knockdown of AKR1B1 lead to mesenchymal-to-epithelial transition in vitro and suppressed EMT induced by TGF-β or by high glucose levels. Besides reduced migration, AKR1B1-deficient cells displayed decreased proliferation rate and colony-formation ability. Moreover, AKR1B1 knockdown or its inhibition with specific drugs diminished cancer stem cells. The phenotypes observed with AKR1B1 knockdown could be obtained by targeting sorbitol dehydrogenase (SORD), the second and last enzyme of the polyol pathway. Suppression of each enzyme resulted in an impaired glycolytic and oxidative metabolism and adding fructose, the end-product of the polyol pathway, rescued the expression of EMT markers. IHC on samples from the AOM-induced colon cancer model indicated a higher AKR1B1 expression in invasive tumors from p53ΔIEC mice as compared to both p53-deficient non-invasive or wildtype tumors. Finally, AKR1B1 staining of cancer tissues from a cohort of lung cancer patients confirmed a significant correlation with EMT and a negative prognostic value.

Conclusion: In summary, we describe a glucose-related pathway with a previously unknown role in regulating cancer plasticity and EMT, which links altered glucose metabolism to growth and migratory ability, with several potential implications. Targeting polyol pathway enzymes could be a potentially effective therapeutic strategy to arrest cancer progression.

Citation Format: Annemarie Schwab, Aarif Siddiqui, Maria Eleni Vazakidou, Francesca Napoli, Martin Boettcher, Bianca Menchicchi, Ida Rapa, Maximilian Waldner, Dimitrios Mougiakakos, Marco Volante, Florian Greten, Thomas Brabletz, Paolo Ceppi. Aldo-keto reductase family 1 member b1 links glucose metabolism to epithelial-to-mesenchymal transition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 450. doi:10.1158/1538-7445.AM2017-450

Abstract 3887: GNA13 is a theranostic target that drives drug resistance and cancer stem-like phenotypes in solid tumors

Treatment failure in solid tumors occurs due to the survival of specific subpopulations of cells that possess stem cell-like (CSC) phenotypes. Studies have implicated G protein-coupled-receptors (GPCRs) in cancer progression and the acquisition of aggressive phenotypes. Many of the implicated GPCRs signal through the G12 subfamily, comprised of GNA12 and GNA13. In this study, we demonstrate that GNA13 is upregulated in many solid tumors and impacts survival and metastases in these patients. Consistent with this, we show that GNA13 expression modulates drug resistance through its effect on the CSC sub-population in a panel of patient-derived head and neck (HNSCC) and breast cancer cells. These data were validated in vivo, where GNA13 over-expression in patient-derived xenografts increased tumor initiating capacity, tumorigenicity and drug resistance, with no effect on growth or proliferation. Signaling through NFKB and MAPK pathways appear to be critical to the observed phenotype. Importantly, blockade of GNA13 expression, or select downstream pathways using small-molecule inhibitors, abrogates GNA13-induced CSCs, rendering cells vulnerable to standard-of-care cytotoxic therapy for these cancers. Taken together, these data indicate that GNA13 expression is a potential prognostic biomarker, and interfering with GNA13-induced signaling provides a novel strategy to block CSCs and drug resistance in solid tumors.

Citation Format: Suhail Ahmed Kabeer Rasheed, Hui Sun Leong, Manikandan Lakshmanan, Anandhkumar Raju, Dhivya Dadlani, Fui-Teen Chong, Ravisankar Rajarethinam, Thakshayeni Skanthakumar, Ern Yu Tan, Jacqueline Siok Gek Hwang, Kok Hing Lim, Daniel Shao-Weng Tan, Paolo Ceppi, Mei Wang, Vinay Tergaonkar, Patrick J. Casey, N. Gopalakrishna Iyer. GNA13 is a theranostic target that drives drug resistance and cancer stem-like phenotypes in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3887. doi:10.1158/1538-7445.AM2017-3887

CD95 and CD95L promote and protect cancer stem cells

CD95 (APO-1/Fas) is a death receptor used by immune cells to kill cancer cells through induction of apoptosis. However, the elimination of CD95 or its ligand, CD95L, from cancer cells results in death induced by CD95R/L elimination (DICE), a type of cell death that resembles a necrotic form of mitotic catastrophe suggesting that CD95 protects cancer cells from cell death. We now report that stimulation of CD95 on cancer cells or reducing miR-200c levels increases the number of cancer stem cells (CSCs), which are more sensitive to induction of DICE than non-CSC, while becoming less sensitive to CD95-mediated apoptosis. In contrast, induction of DICE or overexpression of miR-200c reduces the number of CSCs. We demonstrate that CSCs and non-CSCs have differential sensitivities to CD95-mediated apoptosis and DICE, and that killing of cancer cells can be maximized by concomitant induction of both cell death mechanisms.

Death induced by CD95 or CD95 ligand elimination

CD95 (Fas/APO-1), when bound by its cognate ligand CD95L, induces cells to die by apoptosis. We now show that elimination of CD95 or CD95L results in a form of cell death that is independent of caspase-8, RIPK1/MLKL, and p53, is not inhibited by Bcl-xL expression, and preferentially affects cancer cells. All tumors that formed in mouse models of low-grade serous ovarian cancer or chemically induced liver cancer with tissue-specific deletion of CD95 still expressed CD95, suggesting that cancer cannot form in the absence of CD95. Death induced by CD95R/L elimination (DICE) is characterized by an increase in cell size, production of mitochondrial ROS, and DNA damage. It resembles a necrotic form of mitotic catastrophe. No single drug was found to completely block this form of cell death, and it could also not be blocked by the knockdown of a single gene, making it a promising way to kill cancer cells.

Proteomics of plasma membrane microdomains

Plasma membrane microdomains represent subcompartments of the plasma membrane characterized by a specific lipid and protein composition. The recognition of microdomains in nearly all the eukaryotic membranes has accredited them with specialized functions in health and disease. Several proteomic studies have recently addressed the specific composition of plasma membrane microdomains, and will be reviewed in this paper. Peculiar information has been obtained, but a comprehensive view of the main protein classes required to define the microdomain proteome is still missing. The achievement of this information is slowed by the difficulties encountered in resolving and analyzing hydrophobic proteins, but it could help in understanding the overall function of plasma membrane microdomains and their involvement in human pathology.

Prognostic role of bone sialoprotein in clear cell renal carcinoma

BACKGROUND

Renal cell carcinoma (RCC) follows a variable clinical course related to disease stage and metastatic spread (including to bone). Molecular and genetic factors bear prognostic significance in RCC, including proteins involved in extracellular matrix invasion. Among these, bone sialoprotein (BSP) and osteopontin (OPN) are physiologically implicated in bone metabolism, and have a prognostic role in several tumors. BSP expression was also predictive of bone spread propensity in lung and prostate carcinoma. In RCC, no data are available for BSP, while OPN has been correlated with tumor stage, grade and survival. We aimed to define the predictive (of bone spread) and prognostic role of BSP and OPN immunohistochemical expression in clear cell RCC.

MATERIALS AND METHODS

from a series of 305 renal tumors resected between 1993 and 2002, 75 surgically resected clear cell RCCs with tissue material, clinical data and follow-up information available, were selected for the preliminary series; a second group of 126 chemo-naïve, radically-resected, consecutive RCCs was collected as a validation series. Immunohistochemical expression of BSP and OPN on paraffinized samples was evaluated by H-score [=Σ (intensity × percentage of positively stained cells)].

RESULTS

In the preliminary series, BSP and OPN reactivity was found in 85% and 77% of cases, respectively. No predictive role of bone spread propensity of RCC was identified. Conversely, both BSP and OPN were significantly associated with shorter survival considering median (p=0.002) and upper quartile (p=0.03) expression values, respectively. In the validation group, a prognostic role was confirmed for BSP only (p=0.008), while OPN showed a trend of association with poorer survival (borderline p-value of 0.058).

CONCLUSION

BSP was shown for the first time to be an independent parameter associated with poor prognosis in RCC. Its coexpression with OPN identifies a subgroup of RCC having the worst outcome.

CD95 is part of a let-7/p53/miR-34 regulatory network

The death receptor CD95 (APO-1/Fas) mediates apoptosis induction upon ligation by its cognate ligand CD95L. Two types of CD95 signaling pathways have been identified, which are characterized by the absence (Type I) or presence (Type II) of mitochondrial involvement. Micro(mi)RNAs are small noncoding RNAs that negatively regulate gene expression. They are important regulators of differentiation processes and are found frequently deregulated in many human cancers. We recently showed that Type I cells express less of the differentiation marker miRNA let-7 and, hence, likely represent more advanced tumor cells than the let-7 high expressing Type II cells. We have now identified miR-34a as a selective marker for cells that are sensitive to CD95-mediated apoptosis. Both CD95 and miR-34a are p53 target genes, and consequently, both the sensitivity of cancer cells to CD95-mediated apoptosis and the ability to respond to p53 mediated DNA genotoxic stress are linked. Interestingly, while miR-34a was found to positively correlate with the ability of cells to respond to genotoxic stress, let-7 was negatively correlated. The expression level of CD95 inversely correlated with the expression of let-7 suggesting regulation of let-7 expression by CD95. To test a link between p53 and miR-34a, we altered the expression of CD95. This affected the ability of cells to activate p53 and to regulate miR-34a. Our data point to a novel regulatory network comprising p53, CD95, let-7, and miR-34a that affects cancer cell survival, differentiation, and sensitivity to apoptotic signals. The possible relevance of this regulatory network for cancer stem cells is discussed.

MicroRNA-30a inhibits epithelial-to-mesenchymal transition by targeting Snai1 and is downregulated in non-small cell lung cancer

MicroRNAs (miRNAs) are small non-coding RNAs which regulate gene expression by base-pairing to the 3'-UTR of the target mRNA. Recently, miRNAs have been shown to regulate cancer metastasis, however, central molecular mechanisms of this ability still need to be investigated. Epithelial to mesenchymal transition (EMT), which is characterized especially by repression of E-cadherin expression and increased cell motility, is an essential component of cancer metastasis and progression. In the present study, we found that Snai1, a known transcriptional repressor of E-cadherin and modulator of EMT, is post-transcriptionally targeted by miRNA-30a in non-small cell lung cancer (NSCLC). Consistent with this, microRNA-30a expression was found inversely proportional to the invasive potential of various NSCLC cell lines, correlating positively with E-cadherin (epithelial marker) and negatively with N-cadherin (mesenchymal marker) expression. Forced re-introduction of miR-30a significantly altered cell morphology, in vitro invasion and migration of invasive cell lines, this being paralleled by a downregulation of Snai1 and upregulation of E-cadherin expression. Using a chicken embryonic metastasis assay, we found that miR-30a suppresses in vivo distant metastasis to the lungs and liver. Finally, we screened the expression of miR-30a in 64 consecutively resected NSCLC patients and found that, in 81% of the patients, expression of miR-30a was downregulated significantly (p < 0.0001) in tumors compared to corresponding normal tissues. These results suggest that miR-30a targets Snai1, inhibits invasion and metastasis, and is downregulated in NSCLC.

Expression and pharmacological inhibition of thymidylate synthase and Src kinase in nonsmall cell lung cancer

The combination of cytotoxic chemotherapy with signaling pathway inhibitors represents a potential strategy to improve the treatment of nonsmall cell lung cancer (NSCLC). Thymidylate synthase (TS) is an enzyme essential for DNA synthesis, and its overexpression has been associated with the reduced sensitivity to antifolate agents. Src is a tyrosine kinase that modulates the cytotoxicity of cancer cells after drug treatment, and in vitro data indicate that its inhibition could revert the resistance to TS-inhibiting drugs. Our study investigated the significance of TS and Src expression in NSCLC tissues, and the effects of their pharmacological inhibition in cell lines. In tumor and normal tissues from 94 resected NSCLC patients, TS and Src transcript levels were found positively correlated (R(S) = 0.66), associated with patients smoking history and overall survival. At multivariate analysis, TS gene expression was an independent prognostic factor (relative risk (RR) = 1.78, from 1.16 to 2.72; p < 0.01). Immunohistochemical detection in tumor specimens confirmed that Src kinase activation, evaluated by phospho-specific antibody, was associated to a higher TS expression. In cell lines, dasatinib, a Src-inhibiting agent, synergistically enhanced pemetrexed-cytotoxicity of A549 cells, as evaluated by MTT and apoptosis assays. The biological explanation for this interaction was based on the upregulation of TS messenger RNA and protein levels induced by pemetrexed, which was significantly prevented by dasatinib cotreatment. The data of our study suggest that TS and Src may belong to a common pathway that bears prognostic significance in NSCLC, and that Src represents a potential target to improve the efficacy of TS-inhibiting agents.

Aurora Kinase A expression is associated with lung cancer histological-subtypes and with tumor de-differentiation

BACKGROUND

Aurora kinase A (AURKA) is a member of serine/threonine kinase family. Several kinases belonging to this family are activated in the G2/M phase of the cell cycle being involved in mitotic chromosomal segregation. AURKA overexpression is significantly associated with neoplastic transformation in several tumors and deregulated Aurora Kinases expression leads to chromosome instability, thus contributing to cancer progression. The purpose of the present study was to investigate the expression of AURKA in non small cell lung cancer (NSCLC) specimens and to correlate its mRNA or protein expression with patients' clinico-pathological features.

MATERIALS AND METHODS

Quantitative real-time PCR and immunohistochemistry analysis on matched cancer and corresponding normal tissues from surgically resected non-small cell lung cancers (NSCLC) have been performed aiming to explore the expression levels of AURKA gene.

RESULTS

AURKA expression was significantly up-modulated in tumor samples compared to matched lung tissue (p<0.01, mean log2(FC)=1.5). Moreover, AURKA was principally up-modulated in moderately and poorly differentiated lung cancers (p<0.01), as well as in squamous and adenocarcinomas compared to the non-invasive bronchioloalveolar histotype (p=0.029). No correlation with survival was observed.

CONCLUSION

These results indicate that in NSCLC AURKA over-expression is restricted to specific subtypes and poorly differentiated tumors.

Abstract 1466: Smad 7 induces invasion, migration and in vivo metastasis in Non Small Cell Lung Cancer

Lung cancer is one of the most common cancers, 75% of the cases being non small cell lung cancer (NSCLC). Despite recent advances in the cancer treatment, invasion and metastasis remains the major cause of cancer associated mortality. Metastasis is a multi-step process which involves local invasion, intravasation, dissemination, extravasation, and colonization. Transforming growth factor beta (TGF-β) is known to facilitate metastasis during the advanced stages of cancer via activating the canonical Smad signaling pathway. Smad 7 is an inhibitor of TGF-β signaling and there are previous reports that this protein can promote and inhibit metastasis in different cell lines. However, a distinct role of Smad7 in NSCLC metastasis has not been investigated so far. In the present study, we screened for the basal expression of Smad 7 in different solid cancer cell lines (breast, cervical, colorectal, NSCLC), observing a differential Smad7 expression. Using Q-RT-PCR, we detected a low mRNA expression of Smad 7 in the two NSCLC cells A549 and H1299. We investigated the effect of Smad 7 over expression in these two cell lines using an adenovirus vector (AdSmad7), and confirmed Smad 7 protein expression by western blot. Additionally, we performed MTT cell proliferation assays, which revealed no significant change in proliferation in Smad 7 over expressing cells. In vitro invasion assays, upon over expression of Smad7, showed a 3- fold increase of invasion in A549 and a 2-fold increase in H1299 cells compared to control cells transduced with the empty vector (AdCMV) (p&lt;0.01). Consistent with the data obtained with Matrigel-Invasion Assays, wound healing assays also showed an increased migration of Smad 7 over expressing cells in a time dependent manner. In initial mechanistic studies, we found that Smad 7 over expression caused an increased activation of Src signaling. This was paralled by an increase of promoter activity and mRNA expression of the known downstream targets u-PAR, MMP-2, MMP-7 and MMP-9, proved by reporter gene assays and Q-RT-PCR. To study whether Smad7 affects in vivo metastasis, we performed Chicken embryo metastasis (CAM) assays and found a significant increase in lung metastasis in Smad 7 over expressing H1299 cells (p = 0.01). Finally, to support the clinical relevance obtained by the in vivo and in vitro studies, we screened 48 NSCLC patients for the endogenous expression of Smad7. By Q-RTPCR, we found that patients with a low endogenous Smad 7 expression in resected tumors showed a significantly better overall survival (p = 0.01). This study shows for the first time that Smad7 increases invasion and metastasis of NSCLC cells, this being paralled by Src activation and induced u-PAR and MMPs expression, and that Smad 7 might be a novel prognostic marker in NSCLC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1466. doi:10.1158/1538-7445.AM2011-1466

Regulation of Axl receptor tyrosine kinase expression by miR-34a and miR-199a/b in solid cancer

Axl is a receptor that induces proliferation, migration and invasion in cancer. In this study, we show that specific microRNAs (miRNAs) target the 3'-UTR of Axl. Luciferase-reporter assays with wild-type and deleted miR-34 and miR-199a/b seed sequences of Axl 3'-UTR confirmed the specificity of targeting. An inverse correlation between Axl protein and miR-34a expression in a panel of non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and breast cancer (BRC) cell lines was observed, while miR-199a/b expression was completely suppressed. Pre-miR transfection inhibited in vitro migration and invasion and, in vivo, reduced the number of distant lung- or liver-metastases in a chorion-allantoic-membrane (CAM) assay. Moreover, methylation-specific PCR on bisulfite-converted DNA obtained from the cell lines showed that the miR-34a promoter methylation status was inversely correlated with its expression, and that miR-199a/b promoter regions were methylated in all cells tested. In a panel of NSCLC tissues (n=44), miR-34a and miR-199a/b were found to be downregulated and significantly co-expressed. A lower expression of all three miRs was significantly associated with squamous histotypes, and, in a preliminary series, NSCLC patients with miR-34a upregulation showed a positive association towards a longer survival. These results indicate that Axl receptor expression can be regulated by miR-34a and miR-199a/b, which are suppressed by promoter methylation in solid cancer cells.

Loss of miR-200c expression induces an aggressive, invasive, and chemoresistant phenotype in non-small cell lung cancer

The development of metastases is the main reason for cancer-related death in non-small cell lung cancer (NSCLC). The initiation of metastasis involves an increase in cell motility mediated by the loss of cell-cell adhesion caused by E-cadherin repression, in a process commonly known as epithelial-to-mesenchymal transition. A role for microRNA-200 family members in regulating epithelial-to-mesenchymal transition has recently been indicated but data about their expression in lung tumors is still unavailable. The present study investigated the expression of miR-200c in a panel of NSCLC cell lines (n = 9), and a strong inverse correlation with invasion was detected. Reintroduction of miR-200c into highly invasive/aggressive NSCLC cells induced a loss of the mesenchymal phenotype by restoring E-cadherin and reducing N-cadherin expression, and inhibited in vitro cell invasion as well as in vivo metastasis formation. Moreover, miR-200c overexpression restored the sensitivity of NCI-H1299 cells to cisplatin and cetuximab. Hypermethylation of the promoter region was found to be responsible for the loss of miR-200c in invasive cells, as evaluated by 5-aza-2'-deoxycytidine treatment, methylation-specific PCR, and bisulfite sequencing. In primary tumor specimens obtained from 69 patients with consecutively resected NSCLC, lower miR-200c expression levels were found to be associated with a poor grade of differentiation (P = 0.04), a higher propensity to lymph node metastases (P < 0.01), and with a lower E-cadherin expression (P = 0.01). These data indicate that the loss of miR-200c expression induces an aggressive, invasive, and chemoresistant phenotype, and that assessment of its expression could contribute to a better clinicopathologic definition of patients with NSCLC.

Abstract 2085: Mir-30 acts as an anti-metastatic microRNA and is downregulated in non-small cell lung cancer (NSCLC)

MicroRNAs (miRNAs) are small (around 22 nt) endogenous non-coding RNAs which regulate gene expression by base-pairing to the 3′-UTR of the target mRNA, causing translational repression or mRNA degradation. Recently, miRNAs have been shown to regulate cancer metastasis by virtue of their ability to co-ordinately repress multiple target genes. Epithelial-mesenchymal transition (EMT), which is characterized by repression of E-cadherin expression, and increased cell mobility, plays a very important role in cancer metastasis and fibrosis development. Recent evidence suggests that microRNA-30 (miR-30) acts as an antifibrotic agent and reduces tumor weight in animal models. In the present study, we have identified that the miR-30 family of miRNAs may function as anti-metastatic miRNAs by inhibiting EMT. We have studied the expression of miR-30 in various NSCLC cell lines and found that miR-30 expression is inversely proportional to the invasive capabilities of the cells. Correspondingly, all ‘mir-30 high’ cells are E-cadherin (epithelial marker) positive and N-cadherin (mesenchymal marker) negative, and vice-versa. ‘miR-30 low’ cell lines displayed several fold higher migratory and invasive abilities when compared with ‘miR-30 high’ cell lines. Similarly, in a chicken embryonic metastasis assay, we found that the number of metastasizing cells to lungs and livers of developing chicken was significantly reduced when miR-30 was over-expressed in ‘miR-30 low’ cells compared with mock-transfected cells. Over-expression of miR-30 also inhibited TGF-beta induced EMT in ‘miR-30 low’ cells, confirming the role of miR-30 in EMT inhibition. Search for miR-30 targets, that can modulate E-cadherin expression, using web based target analysis tools, have identified that Snail, which induces EMT primarily via transcriptional repression of E-cadherin, is a putative target of miR-30. Luciferase and Western blotting experiments have confirmed that miR-30 targets Snail. Finally, we have screened the expression of miR-30 in 47 consecutive NSCLC patients and found that miR-30 is down-regulated in tumours of about 80% of patients compared with their corresponding normal tissue. Collectively, these observations suggest that members of miR-30 are down regulated in non-small cell lung cancer, and inhibit EMT by targeting Snail.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2085.

Abstract 2086: Regulation of Axl receptor tyrosine kinase expression, invasion and metastasis by miR-34a and mir-199a/b

Axl is a receptor tyrosine kinase over-expressed in different human cancers which induces proliferation, migration and invasion. In this study, we show that specific microRNAs (miR) can target the 3’-UTR of Axl and can modulate its expression. By a bioinformatics approach, we found conserved target sites for miR-34 and miR-199 within the Axl-3’-UTR at 31-49 nt and 29-56 nt, respectively. Luciferase-reporter assays with wild-type and deleted miR-34 and −199 seed sequences of Axl-3′UTR confirmed the specificity of targeting. An inverse correlation between Axl protein and miR-34a expression in a panel of non-small cell lung cancer (NSCLC), colorectal (CRC) and breast cancer (BRC) cell lines was observed, while no miR-199a or 199b expression was detected. Transient transfection of antagonist-miR or pre-miR for miR-34a and 199a significantly induced and reduced Axl-protein levels, respectively. Pre-miR transfection was able to inhibit in vitro migration and invasion of H1299 and RKO cells and, in vivo, to reduce the number of distant lung- or liver-metastasis in a chicken-embryo-metastasis assay. Moreover, methylation specific PCR on bisulfite-converted DNA obtained from the cell lines showed that the miR-34a promoter methylation status was significantly correlated with Axl expression, and that miR-199a/b promoter regions were methylated in all the cell lines tested. These results suggest that Axl receptor, together with its role in cancer cell growth, invasion and metastasis formation, can be regulated by miR34a and 199a/199b, and that one of the reasons for its over-expression in tumors can be the methylation of DNA that encodes these specific miRs which target Axl expression.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2086.

Thymidylate Synthase But Not Excision Repair Cross-Complementation Group 1 Tumor Expression Predicts Outcome in Patients With Malignant Pleural Mesothelioma Treated With Pemetrexed-Based Chemotherapy

Purpose

The relationship between thymidylate synthase (TS) expression and outcome in patients with malignant pleural mesothelioma (MPM) treated with pemetrexed (P) was retrospectively evaluated.

Patients and Methods

Sixty histologically confirmed patients with MPM previously treated with P and platinum (45 of 60) or as single agent (15 of 60) were retrospectively considered. Eighty-one control patients with MPM not P-treated were also evaluated. TS and excision repair cross-complementation group 1 (ERCC1) gene expression levels were evaluated by real-time polymerase chain reaction and by immunohistochemistry using the H-score.

Results

Median TS H-score value was 90 (range, 5 to 240). A significant correlation between low TS protein expression and longer time to progression (TTP; 17.9 v 7.9 months; hazard ratio [HR], 2.05, 95% CI, 1.19 to 3.77; P = .02) or overall survival (OS; 30 v 16.7 months; HR, 2.38; 95% CI, 1.15 to 4.91; P = .019) was found when patients were divided according to median H-score. Conversely, TS mRNA levels were not significantly correlated with outcome. In platinum-treated patients (n = 45), no correlation was found with survival according to ERCC1 median H-score, but patients in the lower tertile had a significantly shorter survival (HR, 3.06; 95% CI, 1.08 to 8.69; P = .035). In control MPMs, TS had no prognostic role. At multivariate analysis, TS protein levels were the only independent prognostic factor for both TTP (HR, 2.71; 95% CI, 1.13 to 6.49; P = .02) and OS (HR, 6.91; 95% CI, 1.90 to 25.07; P = .003).

Conclusion

In patients with MPM treated with P-based chemotherapy, low TS protein levels are predictive of improved TTP and OS. The role of TS assessment is worth of prospective validation in future studies on MPM.

Differential Thymidylate Synthase Expression in Different Variants of Large-Cell Carcinoma of the Lung

PURPOSE: In non-small cell lung cancer, higher thymidylate synthase (TS) levels have been reported in squamous cell carcinoma (SCC) compared with adenocarcinoma (ADC). Data on TS expression in large-cell carcinoma (LCC) are scanty. EXPERIMENTAL DESIGN: TS mRNA and protein levels were analyzed in 42 surgical cases of pulmonary LCC, including 8 large-cell neuroendocrine carcinomas, and were compared with controls represented by ADC (n = 41), SCC (n = 30), and small-cell lung carcinoma (SCLC; n = 33). TS levels were also correlated with the expression of Ki67 and E2F1. Moreover, the reliability of TS expression analysis was assessed in 22 matched cytologic and surgical specimens of non-small cell lung cancer. RESULTS: TS mRNA levels of LCC were comparable with those of control SCC, but significantly higher than those of ADC (P < 0.001) and lower than SCLC (P < 0.001). A correlation between TS mRNA and protein levels was observed in control ADC and SCC, but not in LCC. Large-cell neuroendocrine carcinomas had the highest TS expression, whereas in non-neuroendocrine LCCs, TS protein levels were significantly higher (P = 0.02) in LCC immunoreactive for p63 and desmocollin3 (markers of squamous differentiation) than those expressing TTF-1 (a marker of ADC). Both E2F1 and Ki67 levels were not correlated with TS in LCCs. Finally, a linear correlation in TS protein levels was observed between matched cytologic and surgical specimens. CONCLUSION: The pulmonary LCC immunoprofile may resemble that of SCCs or ADCs. This immunoprofile is associated with differential TS expression levels, which may support a more appropriate therapeutic strategy decision. (Clin Cancer Res 2009;15(24):7547-52).

Effects of Src kinase inhibition induced by dasatinib in non-small cell lung cancer cell lines treated with cisplatin

c-Src is a tyrosine kinase involved in tumor proliferation, migration, and angiogenesis and has been shown to modulate the cytotoxicity following cisplatin-induced DNA damages. c-Src is frequently activated in non-small cell lung cancer (NSCLC) tissues and cell lines, but no preclinical data regarding the effects of the novel potent Src inhibitor, dasatinib (BMS-354825), in the modulation of cisplatin resistance are currently available. The present study reports that treatment with dasatinib completely abrogated Src phosphorylation in the majority of the NSCLC cell lines tested (n = 7), with modest effects on cell proliferation and survival. In five cell lines, a higher cytotoxicity was observed delivering cisplatin in combination with dasatinib: the most evident effects were found in the squamous H520 cells due to the effective block of cisplatin-induced Src phosphorylation. Moreover, dasatinib treatment significantly blocked cisplatin-induced transcription of a panel of DNA repair and synthesis genes. In addition, a real-time PCR analysis done on tumor and matched normal lung specimens from 44 surgically resected NSCLC patients showed that Src transcripts are significantly upregulated in 23% of cases. In conclusion, Src-directed therapeutic strategies could interfere with cisplatin resistance, possibly allowing to reduce cisplatin doses, thus improving its efficacy. The data of this study support further clinical studies aimed to evaluate the efficacy of Src-inhibiting agents in combination with cisplatin in the treatment of NSCLC.

Polymerase eta mRNA expression predicts survival of non-small cell lung cancer patients treated with platinum-based chemotherapy

PURPOSE

The effect of translesion DNA synthesis system in conferring cellular tolerance to DNA-damaging agents has been recently described. DNA polymerase eta (Pol eta) is part of this machinery and in vitro models showed that it can overcome DNA damages caused by cisplatin and UV rays. The aim of the present study was to investigate the role of Pol eta mRNA expression levels in non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Pol eta mRNA expression levels were evaluated by real-time PCR in (a) formalin-fixed paraffin-embedded biopsies of 72 NSCLC patients treated with platinum-based chemotherapy, (b) fresh snap-frozen surgical specimens of tumor and corresponding normal lung tissue from 50 consecutive patients not treated with perioperative or postoperative chemotherapy, and (c) five NSCLC cell lines.

RESULTS

High Pol eta expression levels were strongly associated with shorter survival at both univariate (6.9 versus 21.1 months; P = 0.003) and multivariate (hazard ratio, 3.18; 95% confidence interval, 1.73-5.84; P = 0.008) analysis in the group of platinum-treated patients. By contrast, Pol eta expression was not significantly correlated with the prognosis in surgically resected patients (P = 0.54) and mRNA levels did not significantly differ in tumor versus normal lung (P = 0.82). Moreover, endogenous Pol eta mRNA expression was found to be inducible by cisplatin in three of five cell lines and significantly associated with in vitro sensitivity (P = 0.01).

CONCLUSIONS

Taken together, these data indicate Pol eta as a predictive rather than prognostic marker worth of further investigation in NSCLC patients candidate to platinum-based chemotherapy.

Updated clinical information on multitargeted antifolates in lung cancer

Pemetrexed, a third-generation antifolate already indicated in combination with cisplatin for the systemic treatment of malignant pleural mesothelioma and, as a single agent, for the second-line treatment of non-small-cell lung cancer was in 2008 granted approval for histologically based first-line treatment by both the EMEA and FDA. Thymidylate synthase, the main molecular target of pemetrexed, has higher mRNA and protein expression in squamous- and small-cell lung cancer compared with adenocarcinoma. This differential expression might well molecularly explain the differential clinical activity of pemetrexed in the various histotypes of lung cancer, including the marginal activity in small-cell lung cancer. These hypothesis-generating findings are currently validated in prospective studies.

Relationship of thymidylate synthase levels to outcome of malignant pleural mesothelioma patients treated with pemetrexed-based chemotherapy

7508

Background: Pemetrexed has shown activity in malignant pleural mesothelioma (MPM) but scanty data are available on the expression of thymidylate synthase (TS), its most important molecular target. Methods: From a database of 75 non-surgical, chemotherapy-naive MPM patients from our Institution in the period 2004–2008, 50 (male/female: 37/13, median age: 65 years) met the selection criteria i.e. epithelial type, availability of thoracoscopic tissue and outcome data. Pemetrexed was administered as single agent (14/50) or in combination with cisplatin or carboplatin (36/50). Retrospectively TS protein expression levels were evaluated by immunohistochemistry and quantified with H-score method. In addition, mRNA extraction was performed in 23 micro-dissected tissues and TS relative levels quantified by RT-PCR. Survival probability was assessed by Kaplan-Meier method and results compared by log-rank test. Cox multivariate analysis for survival was performed adjusting for clinical-pathological variables. Results: Thirty-two patients had progressive disease and 24 had died at the time of the analysis. Median time to progression (TTP) and median survival time (MST) were 11.6 and 20.9 months, respectively. Median TS H-score value was 90 (5–240). No correlation were found with sex, age, PS, stage and chemotherapy regimen. Patients with high TS H-score (4th quartile) had a significantly shorter MST (13.3 vs 21.1 months, p<0.01) and showed a trend for shorter TTP (8.3 vs 11.9 months, p=0.07). Median TS mRNA level was 1.88 (1–3.7 unit-less ratio) and a significant correlation between mRNA and protein expression (RS=0.67, p<0.0001) was found. Patients with high TS mRNA levels (4th quartile) had significantly shorter TTP (8.7 vs 14.7 months, p=0.019) and MST (11.7 vs 24.7, p=0.018). Multivariate analysis for survival indicated that TS protein levels were an independent prognostic factor (HR=2.17; CI 1.04–4.54; p=0.038). Conclusions: TS (protein and mRNA) levels predict outcome of epithelial MPM patients treated with pemetrexed-based chemotherapy. TS quantification, if confirmed in larger prospective studies, could be used to select those patients more likely to respond to chemotherapy.

[Table: see text]

Baseline thymidylate synthase expression according to histological subtypes of non-small cell lung cancer

7521

Background: In non-small cell lung cancer (NSCLC) baseline thymidilate synthase (TS) levels are higher in squamous cell carcinoma (SCC) compared to adenocarcinoma (AC) and randomized clinical trials have shown a selective benefit for patients with non-squamous histology treated with pemetrexed, a TS-inhibiting agent. TS expression in undifferentiated large cell carcinoma (LCC) is unknown. Methods: TS expression at both mRNA (using tissue microdissection and qRT-PCR) and protein (through immunohistochemistry, IHC) levels was tested in 34 surgically resected LCC (stage I=20,II=6,IIIa=8) and compared with TS expression in surgical cases of SCC (n= 31) and AC (n=40). In addition other comparisons were made: a) TS protein expression with Ki-67 index; b) TS mRNA and E2F1 transcription factor mRNA; c) in all histotypes TS protein level with desmocollin-3 (DSC-3) immunostaining, a marker of squamous cell differentiation. TS expression level was assessed in a group of patients (n=22) with cytological diagnosis of NSCLC-NOS (not otherwise specified) and compared with TS data in tissue specimens obtained through subsequent bronchial biopsy or surgical resection. Results: Significantly higher median TS levels in LCC compared to AC (p<0.001 for both mRNA and protein values) and SCC compared to AC (p=0.002 mRNA, p<0.001 protein) were detected. A strong correlation between TS mRNA and protein levels were found (p<0.001) in SCC and AC, but not in LCC. TS and both Ki-67 and E2F1 were significantly correlated in AC and SCC (p=0.003 and p=0.05, respectively), but in LCC no correlation was found. In LCC, significantly higher TS levels were observed in DSC3-positive compared to DSC3-negative tumors (p=0.02). A significant correlation between TS IHC scores in matched cytological and corresponding tissue specimens was observed (p<0.001). Conclusions: This study demonstrates and confirms the: a) differential expression of TS among the NSCLC histotypes; b) lack of DSC-3 immunoreactivity in LCC is associated with lower TS expression; c) assessment of TS by IHC in cytological specimens correlates with the corresponding tissue TS expression.

[Table: see text]

Non-small cell lung cancer exhibits transcript overexpression of genes associated with homologous recombination and DNA replication pathways

Genes involved in DNA repair and replication have been recently investigated as predictive markers of response to chemotherapy in non-small cell lung cancer (NSCLC). However, few data on the expression of these genes in tumor compared with corresponding normal lung are available. The aim of this study was to evaluate differential mRNA levels of 22 DNA repair genes of five different DNA repair pathways: direct, base excision, nucleotide excision (NER), double-strand break (DSBR), and postreplicative repair. In addition, six genes involved in DNA replication (REP) and three telomere maintenance genes were investigated. Total RNAs extracted from fresh-frozen tumors and corresponding normal tissues of 50 consecutive chemo-naïve resected NSCLC patients were analyzed. Transcript levels were quantified by real-time PCR. A significant overexpression was detected in 20 of 30 (67%) genes, mostly belonging to DSBR pathways, whereas others (XPA, XPC, and UBE2N; 10%) were significantly underexpressed. For 7 of 30 (23%) genes, mostly belonging to NER pathway, no significant difference between paired tumor and normal samples was observed. Transcript overexpression of DSBR and REP genes was significantly higher in poorly differentiated carcinomas and DSBR levels were higher in men compared with women. The transcriptional overexpression of four genes (XRCC5, TOP3B, TYMS, and UNG) showed significant correlation with a shorter patients' outcome at the univariate, whereas only stage of disease appeared as an independent factor affecting prognosis, as assessed by multivariate analysis. In conclusion, genes belonging to DNA repair/replication pathways are overexpressed in NSCLC and are associated with a more aggressive phenotype.

Prognostic role of osteopontin expression in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) represents highly aggressive neoplasms with a mean survival of approximately 10 months. Osteopontin, a glycoprotein involved in cell-matrix interactions correlated with invasion and metastatic spread in several tumors, has recently been proposed as a serum marker of MPM in asbestos-exposed subjects. The aim of this study was to define the prognostic role of osteopontin in MPM. For the study, 32 long-term survivors (>24 months) and a random sample of 69 short-term survivors (<or=24 months) were matched according to the main clinicopathologic features. Immunohistochemical osteopontin expression in tissue specimens was quantified through the HScore (histologic scoring) method and correlated with clinicopathologic parameters and survival. Osteopontin expression was significantly lower in long-term compared with short-term survivors (P< .0001), and overall survival analysis showed that low osteopontin expression was associated with longer survival; multivariate analysis confirmed the value of osteopontin expression as an independent prognostic factor (P< .0001).

Thymidylate synthase expression in gastroenteropancreatic and pulmonary neuroendocrine tumors

PURPOSE

The predictive role of the quantification of thymidylate synthase (TS) in tumors treated with antifolate drugs, such as 5-fluorouracil (5-FU), has been extensively reported in a variety of human tumors. Neuroendocrine tumors (NET) represent potential targets of antifolate agents, but no data on TS expression level in these tumors are currently available.

EXPERIMENTAL DESIGN

A series of 116 NETs were collected, including 58 gastroenteropancreatic (GEP) and 58 lung NETs. In 24 well-differentiated GEP neuroendocrine carcinomas (WD-NEC), a 5-FU-based treatment was given. Total RNA was extracted from microdissected paraffin blocks. TS mRNA quantification was done by real-time PCR, whereas protein expression was evaluated by immunohistochemistry.

RESULTS

By means of both quantification by real-time PCR and immunohistochemistry, a higher TS expression in pulmonary small cell lung cancer and large cell NEC compared with typical and atypical carcinoids was observed (P < 0.01). Similarly, in GEP tumors, a higher TS expression in poorly differentiated carcinomas than both WD-NEC and benign tumors (P < 0.01) was found. In patients with WD-NEC treated with 5-FU, high TS mRNA levels were associated with shorter time to progression (P = 0.002) and overall survival (P = 0.04). This negative prognostic role was confirmed in multivariate analysis adjusting for major prognostic variables (P = 0.01). No association between TS mRNA and survival was observed in WD-NEC patients not receiving 5-FU.

CONCLUSIONS

This study, for the first time, (a) reports the differential TS expression in the spectrum of NETs and (b) indicates TS as a possible predictive marker of treatment efficacy in WD-NEC patients treated with 5-FU.

Human ASH1 expression in prostate cancer with neuroendocrine differentiation

Neuroendocrine differentiation in prostate cancer correlates with overall prognosis and disease progression after androgen-deprivation therapy, although its specific mechanisms are currently poorly understood. A role of Notch pathway has been reported in determining neuroendocrine phenotype of normal and neoplastic tissues. The aim of this study was to analyze whether this pathway might affect neuroendocrine differentiation in prostate cancer. Human achaete-scute homolog 1 (hASH1), a pivotal member of the Notch pathway, was investigated in 80 prostate cancers selected and grouped according to chromogranin A immunohistochemistry, as follows: prostate cancers without neuroendocrine differentiation, untreated (25 cases); prostate cancers with neuroendocrine differentiation, untreated (40 cases); prostate cancers with previous androgen-deprivation therapy, all having neuroendocrine differentiation (15 cases). Human ASH1 protein was analyzed by immunohistochemistry, whereas the presence of hASH1 mRNA transcripts was investigated on paraffin material by real-time PCR. By immunohistochemistry, hASH1 was colocalized with chromogranin A in neuroendocrine cells of normal prostatic gland. It was absent in all but one prostate cancers without neuroendocrine differentiation, whereas it was positive in 25% of prostate cancers with neuroendocrine differentiation/untreated, with a significant correlation with the extent of neuroendocrine features (P=0.02). Moreover, comparing untreated and treated prostate cancers with neuroendocrine differentiation, a positive association with androgen-deprivation therapy was observed (P=0.01). In prostate cancers with neuroendocrine differentiation, RNA analysis confirmed the association of higher transcript levels in androgen deprivation-treated compared with untreated patients (P=0.01). In addition, hASH1 mRNA analysis in microdissected chromogranin A-positive and chromogranin A-negative areas within the same tumor demonstrated a two- to sevenfold increase of hASH1 mRNA expression in chromogranin A-positive tumor cell populations.