Persistent DNA damage-induced premature senescence alters the functional features of human bone marrow mesenchymal stem cells.

Human mesenchymal stem cells (hMSCs) are adult multipotent stem cells located in various tissues, including the bone marrow. In contrast to terminally differentiated somatic cells, adult stem cells must persist and function throughout life to ensure tissue homeostasis and repair. For this reason, they must be equipped with DNA damage responses able to maintain genomic integrity while ensuring their lifelong persistence. Evaluation of hMSC response to genotoxic insults is of great interest considering both their therapeutic potential and their physiological functions. This study aimed to investigate the response of human bone marrow MSCs to the genotoxic agent Actinomycin D (ActD), a well-known anti-tumour drug. We report that hMSCs react by undergoing premature senescence driven by a persistent DNA damage response activation, as hallmarked by inhibition of DNA synthesis, p21 and p16 protein expression, marked Senescent Associated ß-galactosidase activity and enlarged γH2AX foci co-localizing with 53BP1 protein. Senescent hMSCs overexpress several senescence-associated secretory phenotype (SASP) genes and promote motility of lung tumour and osteosarcoma cell lines in vitro. Our findings disclose a multifaceted consequence of ActD treatment on hMSCs that on the one hand helps to preserve this stem cell pool and prevents damaged cells from undergoing neoplastic transformation, and on the other hand alters their functional effects on the surrounding tissue microenvironment in a way that might worsen their tumour-promoting behaviour.

ATF2 contributes to cisplatin resistance in non-small cell lung cancer and celastrol induces cisplatin resensitization through inhibition of JNK/ATF2 pathway.

ATF2 is a transcription factor involved in stress and DNA damage. A correlation between ATF2 JNK-mediated activation and resistance to damaging agents has already been reported. The purpose of the present study was to investigate whether ATF2 may have a role in acquired resistance to cisplatin in non-small cell lung cancer (NSCLC). mRNA and protein analysis on matched cancer and corresponding normal tissues from surgically resected NSCLC have been performed. Furthermore, in NSCLC cell lines, ATF2 expression levels were evaluated and correlated to platinum (CDDP) resistance. Celastrol-mediated ATF2/cJUN activity was measured. High expression levels of both ATF2 transcript and proteins were observed in lung cancer specimens (p << 0.01, Log2 (FC) = +4.7). CDDP-resistant NSCLC cell lines expressed high levels of ATF2 protein. By contrast, Celastrol-mediated ATF2/cJUN functional inhibition restored the response to CDDP. Moreover, ATF2 protein activation correlates with worse outcome in advanced CDDP-treated patients. For the first time, it has been shown NSCLC ATF2 upregulation at both mRNA/protein levels in NSCLC. In addition, we reported that in NSCLC cell lines a correlation between ATF2 protein expression and CDDP resistance occurs. Altogether, our results indicate a potential increase in CDDP sensitivity, on Celastrol-mediated ATF2/cJUN inhibition. These data suggest a possible involvement of ATF2 in NSCLC CDDP-resistance.

Human mesenchymal stem cells labelled with dye-loaded amorphous silica nanoparticles: long-term biosafety, stemness preservation and traceability in the beating heart.

BACKGROUND: Treatment of myocardial infarction with mesenchymal stem cells (MSCs) has proven beneficial effects in both animal and clinical studies. Engineered silica nanoparticles (SiO2-NPs) have been extensively used as contrast agents in regenerative medicine, due to their resistance to degradation and ease of functionalization. However, there are still controversies on their effective biosafety on cellular systems. In this perspective, the aims of the present study are: 1) to deeply investigate the impact of amorphous 50 nm SiO2-NPs on viability and function of human bone marrow-derived MSCs (hMSCs); 2) to optimize a protocol of harmless hMSCs labelling and test its feasibility in a beating heart model. RESULTS: Optimal cell labelling is obtained after 16 h exposure of hMSCs to fluorescent 50 nm SiO2-NPs (50 µg mL(-1)); interestingly, lysosomal activation consequent to NPs storage is not associated to oxidative stress. During prolonged culture hMSCs do not undergo cyto- or genotoxicity, preserve their proliferative potential and their stemness/differentiation properties. Finally, the bright fluorescence emitted by internalized SiO2-NPs allows both clear visualization of hMSCs in normal and infarcted rat hearts and ultrastructural analysis of cell engraftment inside myocardial tissue. CONCLUSIONS: Overall, 50 nm SiO2-NPs display elevated compatibility with hMSCs in terms of lack of cyto- and genotoxicity and maintenance of important features of these cells. The demonstrated biosafety, combined with proper cell labelling and visualization in histological sections, make these SiO2-NPs optimal candidates for the purpose of stem cell tracking inside heart tissue.

High basal γH2AX levels sustain self-renewal of mouse embryonic and induced pluripotent stem cells.

Phosphorylation of histone H2AX (γH2AX) is known to be the earliest indicator of DNA double-strand breaks. Recently, it has been shown that mouse embryonic stem cells (mESCs) have very high basal levels of γH2AX, even when they have not been exposed to genotoxic agents. As the specialized role of high basal γH2AX levels in pluripotent stem cells is still debated, we investigated whether H2AX phosphorylation is important in maintaining self-renewal of these cells. Here, we report that not only mESCs but also mouse-induced pluripotent stem cells (miPSCs), have high basal levels of γH2AX. We show that basal γH2AX levels decrease upon ESC and iPSC differentiation and increase when the cells are treated with self-renewal-enhancing small molecules. We observe that self-renewal activity is highly compromised in H2AX-/- cells and that it can be restored in these cells through reconstitution with a wild-type, but not a phospho-mutated, H2AX construct. Taken together, our findings suggest a novel function of H2AX that expands the knowledge of this histone variant beyond its role in DNA damage and into a new specialized biological function in mouse pluripotent stem cells.

Fluorescent silica nanoparticles improve optical imaging of stem cells allowing direct discrimination between live and early-stage apoptotic cells.

Highly bright and photostable cyanine dye-doped silica nanoparticles, IRIS Dots, are developed, which can efficiently label human mesenchymal stem cells (hMSCs). The application procedure used to label hMSCs is fast (2 h), the concentration of IRIS Dots for efficient labeling is low (20 µg mL(-1) ), and the labeled cells can be visualized by flow cytometry, confocal microscopy, and transmission electron microscopy. Labeled hMSCs are unaffected in their viability and proliferation, as well as stemness surface marker expression and differentiation capability into osteocytes. Moreover, this is the first report that shows nonfunctionalized IRIS Dots can discriminate between live and early-stage apoptotic stem cells (both mesenchymal and embryonic) through a distinct external cell surface distribution. On the basis of biocompatibility, efficient labeling, and apoptotic discrimination potential, it is suggested that IRIS Dots can serve as a promising stem cell tracking agent.

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.

Involvement of inflammatory chemokines in survival of human monocytes fed with malarial pigment.

Hemozoin (HZ)-fed monocytes are exposed to strong oxidative stress, releasing large amounts of peroxidation derivatives with subsequent impairment of numerous functions and overproduction of proinflammatory cytokines. However, the histopathology at autopsy of tissues from patients with severe malaria showed abundant HZ in Kupffer cells and other tissue macrophages, suggesting that functional impairment and cytokine production are not accompanied by cell death. The aim of the present study was to clarify the role of HZ in cell survival, focusing on the qualitative and temporal expression patterns of proinflammatory and antiapoptotic molecules. Immunocytochemical and flow cytometric analyses showed that the long-term viability of human monocytes was unaffected by HZ. Short-term analysis by macroarray of a complete panel of cytokines and real-time reverse transcription (RT)-PCR experiments showed that HZ immediately induced interleukin-1ß (IL-1ß) gene expression, followed by transcription of eight additional chemokines (IL-8, epithelial cell-derived neutrophil-activating peptide 78 [ENA-78], growth-regulated oncogene α [GROα], GROß, GROγ, macrophage inflammatory protein 1α [MIP-1α], MIP-1ß, and monocyte chemoattractant protein 1 [MCP-1]), two cytokines (tumor necrosis factor alpha [TNF-α] and IL-1receptor antagonist [IL-1RA]), and the cytokine/chemokine-related proteolytic enzyme matrix metalloproteinase 9 (MMP-9). Furthermore, real-time RT-PCR showed that 15-HETE, a potent lipoperoxidation derivative generated by HZ through heme catalysis, recapitulated the effects of HZ on the expression of four of the chemokines. Intermediate-term investigation by Western blotting showed that HZ increased expression of HSP27, a chemokine-related protein with antiapoptotic properties. Taken together, the present data suggest that apoptosis of HZ-fed monocytes is prevented through a cascade involving 15-HETE-mediated upregulation of IL-1ß transcription, rapidly sustained by chemokine, TNF-α, MMP-9, and IL-1RA transcription and upregulation of HSP27 protein expression.

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.

Mesenchymal stem cell-derived microvesicles protect against acute tubular injury.

Administration of mesenchymal stem cells (MSCs) improves the recovery from acute kidney injury (AKI). The mechanism may involve paracrine factors promoting proliferation of surviving intrinsic epithelial cells, but these factors remain unknown. In the current study, we found that microvesicles derived from human bone marrow MSCs stimulated proliferation in vitro and conferred resistance of tubular epithelial cells to apoptosis. The biologic action of microvesicles required their CD44- and beta1-integrin-dependent incorporation into tubular cells. In vivo, microvesicles accelerated the morphologic and functional recovery of glycerol-induced AKI in SCID mice by inducing proliferation of tubular cells. The effect of microvesicles on the recovery of AKI was similar to the effect of human MSCs. RNase abolished the aforementioned effects of microvesicles in vitro and in vivo, suggesting RNA-dependent biologic effects. Microarray analysis and quantitative real time PCR of microvesicle-RNA extracts indicate that microvesicles shuttle a specific subset of cellular mRNA, such as mRNAs associated with the mesenchymal phenotype and with control of transcription, proliferation, and immunoregulation. These results suggest that microvesicles derived from MSCs may activate a proliferative program in surviving tubular cells after injury via a horizontal transfer of mRNA.

Piroxicam and cisplatin in a mouse model of peritoneal mesothelioma.

PURPOSE: The aim of the present study was to evaluate the effects of piroxicam, a widely used nonsteroidal anti-inflammatory drug, alone and in combination with cisplatin (CDDP), on cell growth of mesothelioma cells. EXPERIMENTAL DESIGN: Cell proliferation, cell cycle analysis, and microarray technology were done on MSTO-211H and NCI-H2452 cells treated with piroxicam. Moreover, the effects of piroxicam and CDDP on tumor growth and survival of mouse xenograft models of mesothelioma were determined. RESULTS: Piroxicam treatment of MSTO-211H and NCI-H2452 cells resulted in a significant inhibition of proliferation. Cell cycle analysis revealed that there was an increase in the rate of apoptosis in MSTO-211H cells and an increase in the cells accumulating in G2-M in NCI-H2452. Moreover, a marked tumor growth inhibition and an extended survival of mice treated with a combination of piroxicam and CDDP in MSTO-211H cell-induced peritoneal mesotheliomas was observed. Last, GeneChip array analysis of MSTO-211H mesothelioma cell line revealed that piroxicam treatment caused up-regulation of metabolic pathway-associated genes and down-regulation of genes related to RNA processing apparatus. Of note, epidermal growth factor receptor, one of the new biological targets of chemotherapy for mesothelioma, was down-regulated and HtrA1, a serine protease recently shown to be an endogenous mediator of CDDP cytotoxicity, was up-regulated following piroxicam treatment both in vitro and in vivo. CONCLUSION: These data suggest that piroxicam sensitizes mesothelioma cells to CDDP-induced cytotoxicity by modulating the expression of several target genes. Therefore, piroxicam in combination with CDDP might potentially be useful in the treatment of patients with mesothelioma.

Genes regulated by hepatocyte growth factor as targets to sensitize ovarian cancer cells to cisplatin.

Advanced ovarian cancers are initially responsive to chemotherapy with platinum drugs but develop drug resistance in most cases. We showed recently that hepatocyte growth factor (HGF) enhances death of human ovarian cancer cell lines treated with cisplatin (CDDP) and that this effect is mediated by the p38 mitogen-activated protein kinase. In this work, we integrated genome-wide expression profiling, in silico data survey, and functional assays to identify transcripts regulated in SK-OV-3 ovarian cancer cells made more responsive to CDDP by HGF. Using oligonucleotide microarrays, we found that HGF pretreatment changes the transcriptional response to CDDP. Quantitative reverse transcription-PCR not only validated all the 15 most differentially expressed genes but also confirmed that they were primarily modulated by the combined treatment with HGF and CDDP and reversed by suppressing p38 mitogen-activated protein kinase activity. Among the differentially expressed genes, we focused functional analysis on two regulatory subunits of the protein phosphatase 2A, which were down-modulated by HGF plus CDDP. Decrease of each subunit by RNA interference made ovarian cancer cells more responsive to CDDP, mimicking the effect of HGF. In conclusion, we show that HGF and CDDP modulate transcription in ovarian cancer cells and that this transcriptional response is involved in apoptosis regulation. We also provide the proof-of-concept that the identified genes might be targeted to either increase the efficacy of chemotherapeutics or revert chemotherapy resistance.

Selection of suitable reference genes for accurate normalization of gene expression profile studies in non-small cell lung cancer.

BACKGROUND: In real-time RT quantitative PCR (qPCR) the accuracy of normalized data is highly dependent on the reliability of the reference genes (RGs). Failure to use an appropriate control gene for normalization of qPCR data may result in biased gene expression profiles, as well as low precision, so that only gross changes in expression level are declared statistically significant or patterns of expression are erroneously characterized. Therefore, it is essential to determine whether potential RGs are appropriate for specific experimental purposes. Aim of this study was to identify and validate RGs for use in the differentiation of normal and tumor lung expression profiles. METHODS: A meta-analysis of lung cancer transcription profiles generated with the GeneChip technology was used to identify five putative RGs. Their consistency and that of seven commonly used RGs was tested by using Taqman probes on 18 paired normal-tumor lung snap-frozen specimens obtained from non-small-cell lung cancer (NSCLC) patients during primary curative resection. RESULTS: The 12 RGs displayed showed a wide range of Ct values: except for rRNA18S (mean 9.8), the mean values of all the commercial RGs and ESD ranged from 19 to 26, whereas those of the microarray-selected RGs (BTF-3, YAP1, HIST1H2BC, RPL30) exceeded 26. RG expression stability within sample populations and under the experimental conditions (tumour versus normal lung specimens) was evaluated by: (1) descriptive statistic; (2) equivalence test; (3) GeNorm applet. All these approaches indicated that the most stable RGs were POLR2A, rRNA18S, YAP1 and ESD. CONCLUSION: These data suggest that POLR2A, rRNA18S, YAP1 and ESD are the most suitable RGs for gene expression profile studies in NSCLC. Furthermore, they highlight the limitations of commercial RGs and indicate that meta-data analysis of genome-wide transcription profiling studies may identify new RGs.

Micro- and Macrostructured PLGA/Gelatin Scaffolds Promote Early Cardiogenic Commitment of Human Mesenchymal Stem Cells In Vitro.

The biomaterial scaffold plays a key role in most tissue engineering strategies. Its surface properties, micropatterning, degradation, and mechanical features affect not only the generation of the tissue construct in vitro, but also its in vivo functionality. The area of myocardial tissue engineering still faces significant difficulties and challenges in the design of bioactive scaffolds, which allow composition variation to accommodate divergence in the evolving myocardial structure. Here we aimed at verifying if a microstructured bioartificial scaffold alone can provoke an effect on stem cell behavior. To this purpose, we fabricated microstructured bioartificial polymeric constructs made of PLGA/gelatin mimicking anisotropic structure and mechanical properties of the myocardium. We found that PLGA/gelatin scaffolds promoted adhesion, elongation, ordered disposition, and early myocardial commitment of human mesenchymal stem cells suggesting that these constructs are able to crosstalk with stem cells in a precise and controlled manner. At the same time, the biomaterial degradation kinetics renders the PLGA/gelatin constructs very attractive for myocardial regeneration approaches.

Six novel ATM mutations in Italian patients with classical ataxia-telangiectasia.

Mutations in the ATM gene are responsible for the autosomal recessive syndrome Ataxia Telangiectasia (AT). In a group of 26 classical AT Italian patients studied by protein truncation test (PTT), we identified six new mutations, never reported so far. Mutations -spread over the entire ATM coding sequence with not clear "hot-spot"- are four frameshifts (2192_2193insA, 3110delC, 7150delA, 8368delA), one splice site alteration (8850G>T, causing exon 63 skipping) and one nonsense change (6913C>T, Q2305X). The identification of ATM gene mutations is important for understanding the molecular basis of the disease, and is essential for diagnosis and genetic counseling.

Microarray data analysis and mining.

DNA microarray is an innovative technology for obtaining information on gene function. Because it is a high-throughput method, computational tools are essential in data analysis and mining to extract the knowledge from experimental results. Filtering procedures and statistical approaches are frequently combined to identify differentially expressed genes. However, obtaining a list of differentially expressed genes is only the starting point because an important step is the integration of differential expression profiles in a biological context, which is a hot topic in data mining. In this chapter an integrated approach of filtering and statistical validation to select trustable differentially expressed genes is described together with a brief introduction on data mining focusing on the classification of co-regulated genes on the basis of their biological function.

The effect of bioartificial constructs that mimic myocardial structure and biomechanical properties on stem cell commitment towards cardiac lineage.

Despite the enormous progress in the treatment of coronary artery diseases, they remain the most common cause of heart failure in the Western countries. New translational therapeutic approaches explore cardiomyogenic differentiation of various types of stem cells in combination with tissue-engineered scaffolds. In this study we fabricated PHBHV/gelatin constructs mimicking myocardial structural properties. Chemical structure and molecular interaction between material components induced specific properties to the substrate in terms of hydrophilicity degree, porosity and mechanical characteristics. Viability and proliferation assays demonstrated that these constructs allow adhesion and growth of mesenchymal stem cells (MSCs) and cardiac resident non myocytic cells (NMCs). Immunofluorescence analysis demonstrated that stem cells cultured on these constructs adopt a distribution mimicking the three-dimensional cell alignment of myocardium. qPCR and immunofluorescence analyses showed the ability of this construct to direct initial MSC and NMC lineage specification towards cardiomyogenesis: both MSCs and NMCs showed the expression of the cardiac transcription factor GATA-4, fundamental for early cardiac commitment. Moreover NMCs also acquired the expression of the cardiac transcription factors Nkx2.5 and TBX5 and produced sarcomeric proteins. This work may represent a new approach to induce both resident and non-resident stem cells to cardiac commitment in a 3-D structure, without using additional stimuli.

p63 and p73 isoform expression in non-small cell lung cancer and corresponding morphological normal lung tissue.

BACKGROUND: The TP73 and TP63 genes are members of the p53 tumor suppressor family and are expressed in different N-terminal isoforms either with proapoptotic (transactivation domain, TA) and antiapoptotic (N-terminally truncated, ΔN) function. Unlike p53, the role of p73 and p63 in tumor is controversial. It has been recently hypothesized that altered ΔN:TA expression ratio, rather than single isoform overexpression, plays a role in the pathogenesis of many diseases, including lung cancer. METHODS: Isoform-specific, real-time polymerase chain reaction and immunohistochemistry analysis on matched cancer and corresponding normal tissues from surgically resected non-small cell lung cancers (NSCLCs) have been performed aiming to explore the expression levels of each p63 and p73 N-terminal isoforms and their ΔN:TA expression ratio. RESULTS: For both p63 and p73, a N-terminal isoform-specific modulation that alter ΔN:TA isoform balance was identified. In particular, ΔNp63 isoform was significantly up-modulated, whereas TAp63 was slightly down-modulated in NSCLC specimens. Likewise, Δ2p73 and Δ2/3p73 were up-modulated, whereas ΔNp73 and ΔN'p73 isoforms were down-modulated. Moreover, a higher TAp63 and ΔN'p73 transcripts expression, detected in the normal tissue surrounding the tumors, correlates with poor patient outcome, representing independent prognostic factors for overall survival (ΔN'p73: p = 0.049, hazard ratio = 3.091, 95% confidence interval = 1.005-9.524 and TAp63: p = 0.001, hazard ratio = 8.091, 95% confidence interval = 2.254-29.05). CONCLUSION: Our findings suggest that p63 and p73 altered ΔN:TA expression ratio occurs in NSCLC likely contributing to the molecular pathogenesis of this tumor.

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).

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.

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.