ADAM17 regulates epidermal growth factor receptor expression through the activation of Notch1 in non-small cell lung cancer

Collateral sensitivity to cold stress and differential BCL-2 family expression in new daunomycin-resistant lymphoblastoid cell lines

The acquisition of a multidrug-resistant (MDR) phenotype by tumor cells is one of the main causes of chemotherapy failure in cancer, and, usually, is due to the increased expression of P-glycoprotein (MDR-1, P-gp, ABCB1), a pump that expels chemotherapeutics from the cell and/or regulates apoptosis. Thus, it is fundamental to find drugs or stress stimuli with a capacity to induce apoptosis in such cells and to identify the mechanisms involved. We address this matter in human cells and establish new daunomycin (DNM)-resistant cell lines (IM-9R) by exposing the parental lymphoblastic cells (IM-9) to increasing doses of the anti-neoplastic drug, daunomycin. The resistance level of IM-9R cell lines, MDR-1 expression and functionality, collateral sensitivity and Bcl-2 and caspases protein expression are analyzed. As a result, we show for the first time that, unlike the parental cells, human lymphoblastic resistant cells exhibit collateral sensitivity to cold stress, confirming that this phenomenon is not exclusive to murine leukemic cells, but a broader one associated with the acquisition of drug resistance. Furthermore, the new resistant cell lines undergo a significant increase in active caspase-3 and -9 levels and drastic changes in Bcl-2 family protein expression during the process of MDR phenotype acquisition.

Phospho-aspirin (MDC-22) inhibits breast cancer in preclinical animal models: an effect mediated by EGFR inhibition, p53 acetylation and oxidative stress

Background

The anticancer properties of aspirin are restricted by its gastrointestinal toxicity and its limited efficacy. Therefore, we synthesized phospho-aspirin (PA-2; MDC-22), a novel derivative of aspirin, and evaluated its chemotherapeutic and chemopreventive efficacy in preclinical models of triple negative breast cancer (TNBC).

Methods

Efficacy of PA-2 was evaluated in human breast cancer cells in vitro, and in orthotopic and subcutaneous TNBC xenografts in nude mice. Mechanistic studies were also carried out to elucidate the mechanism of action of PA-2.

Results

PA-2 inhibited the growth of TNBC cells in vitro more potently than aspirin. Treatment of established subcutaneous TNBC xenografts (MDA-MB-231 and BT-20) with PA-2 induced a strong growth inhibitory effect, resulting in tumor stasis (79% and 90% inhibition, respectively). PA-2, but not aspirin, significantly prevented the development of orthotopic MDA-MB-231 xenografts (62% inhibition). Mechanistically, PA-2: 1) inhibited the activation of epidermal growth factor receptor (EGFR) and suppressed its downstream signaling cascades, including PI3K/AKT/mTOR and STAT3; 2) induced acetylation of p53 at multiple lysine residues and enhanced its DNA binding activity, leading to cell cycle arrest; and 3) induced oxidative stress by suppressing the thioredoxin system, consequently inhibiting the activation of the redox sensitive transcription factor NF-κB. These molecular alterations were observed in vitro and in vivo, demonstrating their relevance to the anticancer effect of PA-2.

Conclusions

Our findings demonstrate that PA-2 possesses potent chemotherapeutic efficacy against TNBC, and is also effective in its chemoprevention, warranting further evaluation as an anticancer agent.

Opposing role of Notch1 and Notch2 in a Kras(G12D)-driven murine non-small cell lung cancer model

Lung cancer is the leading cause of cancer-related deaths worldwide. Recently, we have shown that Notch1 inhibition resulted in substantial cell death of non-small cell lung cancer (NSCLC) cells in vitro. New compounds targeting Notch signal transduction have been developed and are now being tested in clinical trials. However, the tumorigenic role of individual Notch receptors in vivo remains largely unclear. Using a Kras(G12D)-driven endogenous NSCLC mouse model, we analyzed the effect of conditional Notch1 and Notch2 receptor deletion on NSCLC tumorigenesis. Notch1 deficiency led to a reduced early tumor formation and lower activity of MAPK compared with the controls. Unexpectedly, Notch2 deletion resulted in a dramatically increased carcinogenesis and increased MAPK activity. These mice died significantly earlier due to rapidly growing tumor burden. We found that Notch1 regulates Ras/MAPK pathway via HES1-induced repression of the DUSP1 promoter encoding a phosphatase specifically suppressing pERK1/2. Interestingly, Notch1 but not Notch2 ablation leads to decreased HES1 and DUSP1 expression. However, Notch2-depleted tumors showed an appreciable increase in β-catenin expression, a known activator of HES1 and important lung cancer oncogene. Characteristically for β-catenin upregulation, we found that the majority of Notch2-deficient tumors revealed an undifferentiated phenotype as determined by their morphology, E-Cadherin and TTF1 expression levels. In addition, these carcinomas showed aggressive growth patterns with bronchus invasion and obstruction. Together, we show that Notch2 mediates differentiation and has tumor suppressor functions during lung carcinogenesis, whereas Notch1 promotes tumor initiation and progression. These data are further supported by immunohistochemical analysis of human NSCLC samples showing loss or downregulation of Notch2 compared with normal lung tissue. In conclusion, this is the first study characterizing the in vivo functions of Notch1 and Notch2 in Kras(G12D)-driven NSCLC tumorigenesis. These data highlight the clinical importance of a thorough understanding of Notch signaling especially with regard to Notch-targeted therapies.

High NOTCH activity induces radiation resistance in non small cell lung cancer

BACKGROUND AND PURPOSE

Patients with advanced NSCLC have survival rates <15%. The NOTCH pathway plays an important role during lung development and physiology but is often deregulated in lung cancer, making it a potential therapeutic target. We investigated NOTCH signaling in NSCLC and hypothesized that high NOTCH activity contributes to radiation resistance.

MATERIALS AND METHODS

NOTCH signaling in NSCLC patient samples was investigated using quantitative RT-PCR. H460 NSCLC cells with either high or blocked NOTCH activity were generated and their radiation sensitivity monitored using clonogenic assays. In vivo, xenograft tumors were irradiated and response assessed using growth delay. Microenvironmental parameters were analyzed by immunohistochemistry.

RESULTS

Patients with high NOTCH activity in tumors showed significantly worse disease-free survival. In vitro, NOTCH activity did not affect the proliferation or intrinsic radiosensitivity of NSCLC cells. In contrast, xenografts with blocked NOTCH activity grew slower than wild type tumors. Tumors with high NOTCH activity grew significantly faster, were more hypoxic and showed a radioresistant phenotype.

CONCLUSIONS

We demonstrate an important role for NOTCH in tumor growth and correlate high NOTCH activity with poor prognosis and radioresistance. Blocking NOTCH activity in NSCLC might be a promising intervention to improve outcome after radiotherapy.

miR145 targets the SOX9/ADAM17 axis to inhibit tumor-initiating cells and IL-6-mediated paracrine effects in head and neck cancer

ALDH1(+)CD44(+) cells are putative tumor-initiating cells (TIC) in head and neck squamous cell carcinomas (HNC). miR-145 regulates tumorigenicity in various cancers but the breadth of its mechanistic contributions and potential therapeutic applications are not completely known. Here, we report that ALDH1(+)CD44(+)-HNC cells express reduced levels of miR145. SPONGE-mediated inhibition of miR-145 (Spg-miR145) was sufficient to drive tumor-initiating characteristics in non-TICs/ALDH1(-)CD44-negative HNC cells. Mechanistic analyses identified SOX9 and ADAM17 as two novel miR145 targets relevant to this process. miR-145 expression repressed TICs in HNC in a manner associated with SOX9 interaction with the ADAM17 promoter, thereby activating ADAM17 expression. Notably, the SOX9/ADAM17 axis dominated the TIC-inducing activity of miR-145. Either miR-145 suppression or ADAM17 overexpression in non-TICs/ALDH1(-)CD44(-)-HNC cells increased expression and secretion of interleukin (IL)-6 and soluble-IL-6 receptor (sIL-6R). Conversely, conditioned medium from Spg-miR145-transfected non-TICs/ALDH1(-)CD44(-)-HNC cells was sufficient to confer tumor-initiating properties in non-TICs/ALDH1(-)CD44(-)-HNC and this effect could be abrogated by an IL-6-neutralizing antibody. We found that curcumin administration increased miR-145 promoter activity, thereby decreasing SOX9/ADAM17 expression and eliminating TICs in HNC cell populations. Delivery of lentivral-miR145 or orally administered curcumin blocked tumor progression in HNC-TICs in murine xenotransplant assays. Finally, immunohistochemical analyses of patient specimens confirmed that an miR-145(low)/SOX9(high)/ADAM17(high) phenotype correlated with poor survival. Collectively, our results show how miR-145 targets the SOX9/ADAM17 axis to regulate TIC properties in HNC, and how altering this pathway may partly explain the anticancer effects of curcumin. By inhibiting IL-6 and sIL-6R as downstream effector cytokines in this pathway, miR-145 seems to suppress a paracrine signaling pathway in the tumor microenvironment that is vital to maintain TICs in HNC.

Notch3 overexpression associates with poor prognosis in human non-small-cell lung cancer

Notch3 receptor is one of the mammalian Notch family receptors (Notch1-4) which plays an important role in the regulation of cellular proliferation, differentiation, and apoptosis. Overexpression of Notch3 is associated with tumorigenesis. In order to assess the expression of Notch3 in Chinese non-small-cell lung cancer (NSCLC) patients and determine its association with prognosis, we designed a prospective study with five years of follow-up to evaluate Notch3 expression in NSCLC tissues and adjacent non-cancerous normal lung tissues from 131 patients undergoing surgical treatment by immunohistochemistry and western blot analysis. Notch3 had high expression in 67 of 131 cases of NSCLC (51.1 %), which was significantly higher than in adjacent noncancerous lung tissues. Moreover, Notch3 overexpression was significantly correlated with TNM stage (P = 5.41e-07 in squamous cell carcinoma, P = 5.338e-07 in adenocarcinoma) and lymph node metastasis (P = 0.00764 in squamous cell carcinoma, P = 0.01491 in adenocarcinoma). Kaplan-Meier survival analysis showed that the overall survival times in patients expressing Notch3 in NSCLC were shorter. Multivariate analysis further demonstrated that Notch3 was an independent prognostic factor for patients with NSCLC. Therefore, Notch3 might be a useful biomarker to predict the prognosis of patients with NSCLC.

ADAM17 is overexpressed in non-small cell lung cancer and its expression correlates with poor patient survival

The purpose of this study was to assess ADAM17 expression and to explore its contribution to the non-small cell lung cancer (NSCLC). Real-time quantitative reverse transcriptase-polymerase chain reaction was conducted to detect ADAM17 mRNA expression. In addition, ADAM17 expression was analyzed by immunohistochemistry in 124 clinicopathologically characterized NSCLC cases. The correlation of ADAM17 expression with patients' survival rate was assessed by Kaplan-Meier and Cox regression. The expression levels of ADAM17 mRNA and protein in NSCLC tissues were both significantly higher than those in non-cancerous tissues. In addition, high expression of ADAM17 was significantly correlated with tumor grade (P=0.026), tumor size (P=0.001), clinical stage (P=0.016), and lymph node metastases (P<0.001). Furthermore, multivariate analysis suggested that tumor grade, tumor size, clinical stage, lymph node metastases, and ADAM17 expression were independent prognostic indicators for NSCLC. Our data suggest for the first time that the increased expression of ADAM17 in NSCLC is associated significantly with aggressive progression and poor prognosis. ADAM17 may be an important molecular marker for predicting the carcinogenesis, progression, and prognosis of NSCLC.

ADAM17 promotes U87 glioblastoma stem cell migration and invasion

Glioblastoma stem cells (GSCs) are thought to contribute to the diffuse invasiveness of malignant gliomas. Emerging evidence supports a role for a disintegrin and metalloproteinase 17 (ADAM17) in proteolytic ectodomain shedding of several EGFR-binding ligands, which subsequently activate PI3K/AKT and MEK/ERK pathways through EGFR phosphorylation thus mediating glioma invasiveness. However, it is not clear if ADAM17 also plays important roles in promoting GSC invasion. In this study, we isolated CD133+ GSCs from the human glioblastoma cell line U87 using fluorescence-activated cell sorting and demonstrated their increased invasive potential compared with matched non-stem tumor cells. Furthermore, we showed that CD133+ GSCs expressed higher levels of ADAM17. Immunofluorescence staining revealed that high expression levels of ADAM17 at the invasive front were correlated with the presence of CD133+ GSCs in human glioblastoma specimens. Stimulation with the ADAM17 agonist chemokine phorbol myristate acetate increased migration and invasion of GSCs, which was counteracted by ADAM17 knockdown. In addition, ADAM17 also induced CD133+ GSC invasion via activation of the EGFR/PI3K/AKT signaling pathway. These findings suggest that ADAM17 is involved in U87 GSC invasive process and may provide a potential therapeutic target for glioma treatment.

ADAM17-overexpressing breast cancer cells selectively targeted by antibody-toxin conjugates

A disintegrin and metalloproteinase 17 (ADAM17) is significantly upregulated not only in malignant cells but also in the pro-inflammatory microenvironment of breast cancer. There, ADAM17 is critically involved in the processing of tumor-promoting proteins. Therefore, ADAM17 appears to be an attractive therapeutic target to address not only tumor cells but also the tumor-promoting environment. In a previous study, we generated a monoclonal anti-ADAM17 antibody (A300E). Although showing no complement-dependent cytotoxicity or antibody-dependent cellular cytotoxicity, the antibody was rapidly internalized by ADAM17-expressing cells and was able to transport a conjugated toxin into target cells. As a result, doxorubicin-coupled A300E or Pseudomonas exotoxin A-loaded A300E was able to kill ADAM17-expressing cells. This effect was strictly dependent on the presence of ADAM17 on the surface of target cells. As a proof of principle, both immunotoxins killed MDA-MB-231 breast cancer cells in an ADAM17-dependent manner. These data suggest that the use of anti-ADAM17 monoclonal antibodies as a carrier might be a promising new strategy for selective anti-cancer drug delivery.

ADAM17 regulates self-renewal and differentiation of U87 glioblastoma stem cells

Glioblastoma stem cells (GSCs) play an important role in the progression and recurrence of malignant glioblastoma because of their potential for self-renewal, multilineage differentiation and tumor initiation. A disintegrin and metalloproteinase 17 (ADAM17) is responsible for the proteolytic cleavage of Notch within its extracellular domain leading to the activation of Notch signaling, which is involved in the formation and maintenance of GSCs. Here, we show that glioma cells expressing the stem cell marker CD133 coexpress higher levels of ADAM17 than matched CD133-glioma cells. Knockdown of the ADAM17 gene in U87 GSCs down-regulated the expression of CD133, inhibited secondary neurosphere formation and induced multi-lineage differentiation. Furthermore, knockdown of ADAM17 inhibited Hes1 and Hes5 and activated Notch1 expression, which may explain the ADAM17 shRNA-induced suppression of self-renewal and differentiation of U87 GSCs. Our results suggest that ADAM17 may maintain the stemness of GSCs by promoting their self-renewal and inhibiting their differentiation via Notch signaling.

Analysis of the expression of the Notch3 receptor protein in adult lung cancer

Abnormalities in the Notch signaling system are considered to play a role in the tumorigenesis of bronchiogenic carcinoma. The present study aimed to investigate the expression of Notch3 in adult lung cancer patients and its role in the pathogenesis of primary bronchiogenic carcinoma. The expression of the Notch3 protein in lung squamous cell carcinoma, adenocarcinoma, small cell carcinoma and corresponding non-tumor tissues was detected by immunohistochemistry. To investigate the expression of Notch3 in adenocarcinoma tissues, Notch3 mRNA and protein expression were measured with reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. It was demonstrated that Notch3 had a stronger positive degree of expression in lung squamous cell carcinoma and adenocarcinoma compared with the corresponding non-tumor tissue (P<0.01). The expression of Notch3 in small cell carcinoma tissue was lower compared with that of the corresponding non-tumor tissue (P<0.01). The expression of Notch3 in the lung adenocarcinoma group was the highest of the three lung carcinoma groups (P<0.01). RT-PCR revealed that the expression of Notch3 mRNA in the lung adenocarcinoma group was higher than that of the normal lung group, but there was no statistically significant difference (P=0.05). The expression of Notch1 protein in the lung adenocarcinoma group was significantly higher compared with the normal lung group (P<0.01), as shown by western blot analysis. Notch3 may be involved in the pathogenesis of bronchogenic carcinoma, in particular in the promotion of the lung cancer oncogene, and a difference in its expression may exist in the various pathological types.

Acquisition of MDR phenotype by leukemic cells is associated with increased caspase-3 activity and a collateral sensitivity to cold stress

The acquisition of a multidrug-resistant (MDR) phenotype by tumor cells that renders them unsusceptible to anti-neoplasic agents is one of the main causes of chemotherapy failure in human malignancies. The increased expression of P-glycoprotein (MDR1, P-gp, ABCB1) in tumor cells contributes to drug resistance by extruding chemotherapeutic agents or by regulating programmed cell death. In a study of MDR cell survival under cold stress conditions, it was found that resistant leukemic cells with P-gp over-expression, but not their sensitive counterparts, are hypersensitive to cold-induced cell death when exposed to temperatures below 4 °C. The transfection of parental cells with a P-gp-expressing plasmid makes these cells sensitive to cold stress, demonstrating an association between P-gp expression and cell death at low temperatures. Furthermore, we observed increased basal expression and activity of effector caspase-3 at physiological temperature (37 °C) in MDR cells compared with their parental cell line. Treatment with a caspase-3 inhibitor partially rescues MDR leukemic cells from cold-induced apoptosis, which suggests that the cell death mechanism may require caspase-3 activity. Taken together, these findings demonstrate that P-gp expression plays a role in MDR cell survival, and is accompanied by a collateral sensitivity to death induced by cold stress. These findings may assist in the design of specific therapeutic strategies to complement current chemotherapy treatment against cancer.

Alpha-secretase inhibition reduces human glioblastoma stem cell growth in vitro and in vivo by inhibiting Notch

The Notch pathway is dysregulated and a potential target in glioblastoma multiforme (GBM). Currently available Notch inhibitors block γ-secretase, which is necessary for Notch processing. However, Notch is first cleaved by α-secretase outside the plasma membrane, via a disintegrin and metalloproteinase-10 and -17. In this work, we used a potent α-secretase inhibitor (ASI) to test inhibition of glioblastoma growth and inhibition of Notch and of both novel and known Notch targets. Featured in this study are luciferase reporter assays and immunoblot, microarray analysis, chromatin immunoprecipitation (ChIP), quantitative real-time PCR, cell number assay, bromodeoxyuridine incorporation, plasmid rescue, orthotopic xenograft model, and local delivery of treatment with convection-enhanced delivery using nanoparticles, as well as survival, MRI, and ex vivo luciferase assay. A CBF1-luciferase reporter assay as well as an immunoblot of endogenous Notch revealed Notch inhibition by the ASI. Microarray analysis, quantitative real-time PCR, and ChIP of ASI and γ-secretase inhibitor (GSI) treatment of GBM cells identified known Notch pathway targets, as well as novel Notch targets, including YKL-40 and leukemia inhibitory factor. Finally, we found that local nanoparticle delivery of ASIs but not GSIs increased survival time significantly in a GBM stem cell xenograft treatment model, and ASI treatment resulted in decreased tumor size and Notch activity. This work indicates α-secretase as an alternative to γ-secretase for inhibition of Notch in GBM and possibly other cancers as well, and it identifies novel Notch targets with biologic relevance and potential as biomarkers.

Anti-tumour effects of a specific anti-ADAM17 antibody in an ovarian cancer model in vivo

ADAM 17 (TNF-α converting enzyme, TACE) is a potential target for cancer therapy, but the small molecule inhibitors reported to date are not specific to this ADAM family member. This membrane-bound metalloproteinase is responsible for ectodomain shedding of pathologically significant substrates including TNF-α and EGFR ligands. The aim of this study was to evaluate the pharmacokinetics, pharmacodynamics and anti-tumour efficacy of the first specific inhibitor, an anti-human ADAM17 IgG antibody, clone D1(A12). We used intraperitoneal xenografts of the human ovarian cancer cell line IGROV1-Luc in Balb/c nude mice, chosen because it was previously reported that growth of these xenografts is inhibited by knock-down of TNF-α. In vitro, 200 nM D1(A12) inhibited shedding of ADAM17 substrates TNF-α, TNFR1-α, TGF-α, amphiregulin (AREG), HB-EGF and IL-6Rα, from IGROV1-Luc cells, (4.7 nM IC(50) for TNF-α shedding). In IGROV1-Luc xenografts in vivo, D1(A12) IgG showed pharmacokinetic properties suitable for efficacy studies, with a single i.p. dose of 10 mg/kg D1(A12) sufficient to maintain IgG plasma and ascites fluid concentrations above 100 nM for more than 7 days. The plasma half life was 8.6 days. Next, an efficacy study was performed, dosing D1(A12) or anti-human TNF-α antibody infliximab at 10 mg/kg q7d, quantifying IGROV1-Luc tumour burden by bioluminescence. D1(A12) IgG showed a significant reduction in tumour growth (p = 0.005), 56% of vehicle control. Surprisingly, D1(A12) did not reduce the concentration of circulating human TNF-α, suggesting that another enzyme may compensate for inhibition of ADAM17 in vivo (but not in vitro). However, D1(A12) did show clear pharmacodynamic effects in the mice, with significant inhibition of shedding from tumour of ADAM17 substrates TNFR1-α, AREG, and TGF-α (4-15-fold reductions, p<0.0001 for all three). Thus, D1(A12) has anti-ADAM17 activity in vivo, inhibits shedding of EGFR ligands and has potential for use in EGF ligand-dependent tumours.

A novel bispecific single-chain antibody for ADAM17 and CD3 induces T-cell-mediated lysis of prostate cancer cells

ADAM17 (A disintegrin and metalloproteinase 17) is a membrane-bound protease that cleaves various cell surface proteins, including cytokines and cytokine receptors. Recently it was shown that ADAM17 is highly expressed on the surface of many cancer cells, whereas normal cells express low levels of ADAM17, implying that ADAM17 is a potential immunotherapeutic target. We have generated a monoclonal antibody against human ADAM17, which recognized the membrane proximal cysteine-rich extension of the ADAM17 protein. Unlike normal cells, tumour cell lines, such as a prostate cancer cell line, pancreatic cancer cell lines, a breast cancer cell line and a non-small lung cancer cell line, expressed ADAM17 on the cell surface. Using the sequence of the antibody we generated an ADAM17-specific scFv (single-chain variable fragment) and fused this to a CD3-specific scFv to generate a bispecific T-cell engager antibody [A300E-BiTE (bispecific T-cell engager antibody)]. Specificity was demonstrated on cells in which ADAM17 was knocked down with a specific shRNA (short hairpin RNA). A300E-BiTE recognized ADAM17 and CD3 on the cell surface of tumour cells and T-cells respectively. In the presence of primary human peripheral blood mononuclear cells or human T-cells the addition of A300E-BiTE led to ADAM17-specific killing of prostate tumour cells indicating a novel strategy for the treatment of cancer.

Notch1 signaling promotes survival of glioblastoma cells via EGFR-mediated induction of anti-apoptotic Mcl-1

The Notch1-mediated signaling pathway has a central role in the maintenance of neural stem cells and contributes to growth and progression of glioblastomas, the most frequent malignant brain tumors in adults. Here, we demonstrate that the Notch1 receptor promotes survival of glioblastoma cells by regulation of the anti-apoptotic Mcl-1 protein. Notch1-dependent regulation of Mcl-1 occurs cell type dependent at a transcriptional or post-translational level and is mediated by the induction of epidermal growth factor receptor (EGFR). Inhibition of the Notch1 pathway overcomes apoptosis resistance and sensitizes glioblastoma cells to apoptosis induced by ionizing radiation, the death ligand TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) or the Bcl-2/Bcl-XL inhibitor ABT-737. In conclusion, targeting Notch1 might represent a promising novel strategy in the treatment of glioblastomas.

A genome wide association study of pulmonary tuberculosis susceptibility in Indonesians

Background

There is reason to expect strong genetic influences on the risk of developing active pulmonary tuberculosis (TB) among latently infected individuals. Many of the genome wide linkage and association studies (GWAS) to date have been conducted on African populations. In order to identify additional targets in genetically dissimilar populations, and to enhance our understanding of this disease, we performed a multi-stage GWAS in a Southeast Asian cohort from Indonesia.

Methods

In stage 1, we used the Affymetrix 100 K SNP GeneChip marker set to genotype 259 Indonesian samples. After quality control filtering, 108 cases and 115 controls were analyzed for association of 95,207 SNPs. In stage 2, we attempted validation of 2,453 SNPs with promising associations from the first stage, in 1,189 individuals from the same Indonesian cohort, and finally in stage 3 we selected 251 SNPs from this stage to test TB association in an independent Caucasian cohort (n = 3,760) from Russia.

Results

Our study suggests evidence of association (P = 0.0004-0.0067) for 8 independent loci (nominal significance P < 0.05), which are located within or near the following genes involved in immune signaling: JAG1, DYNLRB2, EBF1, TMEFF2, CCL17, HAUS6, PENK and TXNDC4.

Conclusions

Mechanisms of immune defense suggested by some of the identified genes exhibit biological plausibility and may suggest novel pathways involved in the host containment of infection with TB.

Prognostic value of ADAM17 in human gastric cancer

A disintegrin and metalloproteinase-17 (ADAM17, also named as tumor necrosis factor-alpha-converting enzyme) is a member of the ADAM family. Of all ADAMs, the strongest evidence for a role in malignancy exists for ADAM17. Especially, it has been demonstrated that ADAM17 expression was significantly increased in human gastric cancer. The aim of this study was to investigate the association between ADAM17 expression and the clinicopathological features of patients with gastric cancer. The expression of ADAM17 was detected by real-time quantitative RT-PCR in gastric cancer and adjacent non-cancerous tissues. In addition, ADAM17 expression was analyzed by immunohistochemistry in 220 clinicopathologically characterized gastric cancer cases. The expression levels of ADAM17 mRNA and protein in gastric cancer tissues were both significantly higher than those in non-cancerous gastric mucosa. In addition, positive expression of ADAM17 correlated with the degree of tumor differentiation, depth of invasion, lymph node metastases, distant metastases, and TNM stage (all P<0.05). Furthermore, multivariate analysis suggested that lymph node metastases, distant metastases, TNM stage, and ADAM17 expression were independent prognostic indicators for gastric cancer. Our data suggest for the first time that the increased expression of ADAM17 in gastric cancer is associated significantly with aggressive progression and poor prognosis. ADAM17 may be an important molecular marker for predicting the carcinogenesis, progression, and prognosis of gastric cancer.

Notch signaling in lung cancer

Lung cancer is the leading cause of cancer-related deaths in the Western world. The lungs can be affected by a number of histologically diverse malignancies. Nonetheless, the vast majority of lung cancers are classified as non-small-cell lung cancer (NSCLC). Despite extensive research on different therapeutic regimens, the overall 5-year survival of patients diagnosed with NSCLC (all stages) is a dismal 15%. Although strongly correlated with tobacco smoke, there is an increasing NSCLC morbidity in individuals who have never smoked. The pattern of genetic lesions found in NSCLC derived from smokers and never-smokers appears to be different. This fact led to the hypothesis that different, still unidentified carcinogens are responsible for lung cancer onset in never-smokers. All the aforementioned considerations compel the scientific community to find novel therapeutic targets to fight such a deadly disease. In recent years critical pathways governing embryonic development have been increasingly linked to cancer. Here we will focus on the role of Notch signaling in lung cancer. Notch receptors' activity can be blocked through the use of different strategies, thus representing a promising alternative/complement to the arsenal of therapeutic strategies currently used to treat lung cancer.

ADAM17: a molecular switch to control inflammation and tissue regeneration

A disintegrin and metalloproteinase 17 (ADAM17), also known as tumor necrosis factor-α converting enzyme (TACE), is a membrane-bound enzyme that cleaves cell surface proteins, such as cytokines (e.g. TNFα), cytokine receptors (e.g. IL-6R and TNF-R), ligands of ErbB (e.g. TGFα and amphiregulin) and adhesion proteins (e.g. L-selectin and ICAM-1). Here we examine how ectodomain shedding of these molecules can alter their biology and impact on immune and inflammatory responses and cancer development. Gene targeting of Adam17 is embryonic lethal, highlighting the importance of ectodomain shedding during development. Tissue-specific deletion, or hypomorphic knock-in, of Adam17 demonstrates an in vivo role for ADAM17 in controlling inflammation and tissue regeneration. The potential of ADAM17 as therapeutic target is also discussed.

High tumor levels of IL6 and IL8 abrogate preclinical efficacy of the γ-secretase inhibitor, RO4929097

Interest continues to build around the early application of patient selection markers to prospectively identify patients likely to show clinical benefit from cancer therapies. Hypothesis generation and clinical strategies often begin at the preclinical stage where responder and nonresponder tumor cell lines are first identified and characterized. In the present study, we investigate the drivers of in vivo resistance to the γ-secretase inhibitor RO4929097. Beginning at the tissue culture level, we identified apparent IL6 and IL8 expression differences that characterized tumor cell line response to RO4929097. We validated this molecular signature at the preclinical efficacy level identifying additional xenograft models resistant to the in vivo effects of RO4929097. Our data suggest that for IL6 and IL8 overexpressing tumors, RO4929097 no longer impacts angiogenesis or the infiltration of tumor associated fibroblasts. These preclinical data provide a rationale for preselecting patients possessing low levels of IL6 and IL8 prior to RO4929097 dosing. Extending this hypothesis into the clinic, we monitored patient IL6 and IL8 serum levels prior to dosing with RO4929097 during Phase I. Interestingly, the small group of patients deriving some type of clinical benefit from RO4929097 presented with low baseline levels of IL6 and IL8. Our data support the continued investigation of this patient selection marker for RO4929097 and other types of Notch inhibitors undergoing early clinical evaluation.

Overexpression of TACE and TIMP3 mRNA in head and neck cancer: association with tumour development and progression

BACKGROUND

TACE/ADAM17 is a transmembranous protease that cleaves membrane-bound growth factors like EGFR ligands. TACE-dependent proteolysis is regulated by its inhibitor, tissue inhibitor of metalloproteinases 3 (TIMP3). This study analyses the role of TACE and TIMP3 mRNA expression in squamous cell carcinomas of the head and neck (HNSCCs).

METHODS

We analysed TACE and TIMP3 mRNA expression in HNSCCs from 106 patients by RNA in situ hybridisation.

RESULTS

TACE mRNA was upregulated in HNSCCs compared with dysplastic (P<0.05) and normal epithelia (P<0.001), with strong hybridisation signals in 21.9% of invasive tumour tissues and 4.5% of dysplasia. Elevated mRNA levels were accompanied by increased amounts of TACE protein in HNSCCs. TIMP3 mRNA expression in HNSCC-associated stroma was significantly higher than in the stroma adjacent to dysplastic or normal epithelia. Expression of TACE mRNA in HNSCCs was associated with tumour stage (P=0.019) and regional lymph node metastasis (P=0.009). Furthermore, levels of TACE mRNA in HNSCCs correlated with the expression of TIMP3 mRNA in HNSCC-associated stroma. Concomitantly, patients expressing high levels of TACE and TIMP3 mRNA showed significantly reduced overall survival compared with those with low mRNA levels.

CONCLUSION

Our results indicate an important role of TACE and TIMP3 during development and progression of HNSCCs.