IL-33 increases ST2+ Tregs and promotes metastatic tumour growth in the lungs in an amphiregulin-dependent manner.

Regulatory T cells (Tregs) facilitate primary and metastatic tumour growth through the suppression of anti-tumour immunity. Emerging evidence suggests a distinct role for Tregs in mediating tissue repair and barrier integrity in the lungs by IL-33 mediated production of the growth factor amphiregulin (AREG). Dependent on the type of cancer and local microenvironment, AREG may induce tumour cell proliferation, invasion, migration or resistance to apoptosis by signaling through the epidermal growth factor receptor (EGFR). We have found that IL-33 is dramatically increased in and around metastatic tumour foci in the lungs of mice bearing orthotopic murine mammary tumours. We observed that Tregs express significantly more of the IL-33 receptor, ST2, relative to conventional T cells, that ST2+ Tregs accumulate in the lungs of metastatic tumour-bearing mice, and that ST2+ Tregs produce significantly more AREG than ST2- Tregs. The intranasal administration of recombinant IL-33 increased the proportion of AREG producing ST2+ Tregs and enhanced the level of phosphorylated EGFR in the metastatic lungs. While recombinant AREG did not impact mammary tumour cell proliferation in vitro despite inducing a dose-dependent increase in phosphorylated EGFR, intranasal administration of AREG resulted in a ten-fold increase in pulmonary metastatic tumour burden in vivo. Further, the intranasal administration of recombinant IL-33 significantly increased metastatic tumour burden in the lungs in an amphiregulin-dependent manner. These data identify ST2+ Tregs as a microenvironmental source of AREG in the lungs of mice with orthotopic metastatic mammary tumours and highlight an important role for AREG in promoting metastatic tumour growth in the lungs.

Coiled-coil domain containing 68 (CCDC68) demonstrates a tumor-suppressive role in pancreatic ductal adenocarcinoma.

Using integrative genomics and functional screening, we identified coiled-coil domain containing 68 (CCDC68) as a novel putative tumor suppressor gene (TSG) in pancreatic ductal adenocarcinoma (PDAC). CCDC68 allelic losses were documented in 48% of primary PDAC patient tumors, 50% of PDAC cell lines and 30% of primary patient derived xenografts. We also discovered a single nucleotide polymorphism (SNP) variant (SNP rs1344011) that leads to exon skipping and generation of an unstable protein isoform CCDC68Δ(69-114) in 31% of PDAC patients. Overexpression of full length CCDC68 (CCDC68(wt)) in PANC-1 and Hs.766T PDAC cell lines lacking CDCC68 expression decreased proliferation and tumorigenicity in scid mice. In contrast, the downregulation of endogenous CCDC68 in MIAPaca-2 cells increased tumor growth rate. These effects were not observed with the deletion-containing isoform, CCDC68Δ(69-114).

Ubiquilin1 represses migration and epithelial-to-mesenchymal transition of human non-small cell lung cancer cells.

Ubiquilin1 (UBQLN1) is a ubiquitin-like domain and a ubiquitin-associated domain containing protein that has been reported to be involved in shuttling proteins to the proteasome, especially during endoplasmic reticulum-associated protein degradation. Thus, UBQLN1 function has been shown to be critical for combating a number of neurological disorders caused by protein aggregation, such as amyotrophic lateral sclerosis, Alzheimer's disease and Huntington's disease. A role for UBQLN1 in regulating processes involved in tumorigenesis has not been demonstrated. Herein, we show that loss of UBQLN1 causes increased cell migration and invasion, actin cytoskeleton reorganization and induction of epithelial-to-mesenchymal transition (EMT). Loss of UBQLN1 results in a significant decrease in the expression of epithelial markers including E-cadherin and claudin1, whereas expression of mesenchymal markers including Vimentin, Snail and ZEB1 are significantly elevated. Interestingly, we found that ZEB1 is required for induction of mesenchymal-like properties following loss of UBQLN1 and ZEB1 is capable of repressing expression of UBQLN1, suggesting a physiological, reciprocal regulation of EMT by UBQLN1 and ZEB1. Further, we find evidence for a role for UBQLN2 in also regulating EMT and cell migration. These observations have potential clinical relevance because the UBQLN1 gene is lost and underexpressed in a large percentage of human cancer cell lines, and primary human lung cancer samples and recurrent mutations in all five UBQLN family members have been identified in human lung cancers. Taken together, our results suggest for the first time a role for UBQLN family members in cancer biology.

EYA4 is inactivated biallelically at a high frequency in sporadic lung cancer and is associated with familial lung cancer risk.

In an effort to identify novel biallelically inactivated tumor suppressor genes (TSGs) in sporadic invasive and preinvasive non-small-cell lung cancer (NSCLC) genomes, we applied a comprehensive integrated multiple 'omics' approach to investigate patient-matched, paired NSCLC tumor and non-malignant parenchymal tissues. By surveying lung tumor genomes for genes concomitantly inactivated within individual tumors by multiple mechanisms, and by the frequency of disruption in tumors across multiple cohorts, we have identified a putative lung cancer TSG, Eyes Absent 4 (EYA4). EYA4 is frequently and concomitantly deleted, hypermethylated and underexpressed in multiple independent lung tumor data sets, in both major NSCLC subtypes and in the earliest stages of lung cancer. We found that decreased EYA4 expression is not only associated with poor survival in sporadic lung cancers but also that EYA4 single-nucleotide polymorphisms are associated with increased familial cancer risk, consistent with EYA4s proximity to the previously reported lung cancer susceptibility locus on 6q. Functionally, we found that EYA4 displays TSG-like properties with a role in modulating apoptosis and DNA repair. Cross-examination of EYA4 expression across multiple tumor types suggests a cell-type-specific tumorigenic role for EYA4, consistent with a tumor suppressor function in cancers of epithelial origin. This work shows a clear role for EYA4 as a putative TSG in NSCLC.

SOX15 is a candidate tumor suppressor in pancreatic cancer with a potential role in Wnt/ß-catenin signaling.

Pancreatic cancer is among the top five deadliest cancers in developed countries. Better knowledge of the molecular mechanisms contributing to its tumorigenesis is imperative to improve patient prognosis. Identification of novel tumor suppressor genes (TSGs) in pancreatic cancer will reveal new mechanisms of pathway deregulation and will ultimately help improve our understanding of this aggressive disease. According to Knudson's two-hit model, TSGs are classically disrupted by two concerted genetic events. In this study, we combined DNA methylation profiling with copy number and mRNA expression profiling to identify novel TSGs in a set of 20 pancreatic cancer cell lines. These data sets were integrated for each of ∼12 000 genes in each cell line enabling the elucidation of those genes that undergo DNA hypermethylation, copy-number loss and mRNA downregulation simultaneously in multiple cell lines. Using this integrative genomics strategy, we identified SOX15 (sex determining region Y-box 15) as a candidate TSG in pancreatic cancer. Expression of SOX15 in pancreatic cancer cell lines with undetectable expression resulted in reduced viability of cancer cells both in vitro and in vivo demonstrating its tumor suppressive capability. We also found reduced expression, homozygous deletion and aberrant DNA methylation of SOX15 in clinical pancreatic tumor data sets. Furthermore, we deduced a novel role for SOX15 in suppressing the Wnt/ß-catenin signaling pathway, which we hypothesize is a pathway through which SOX15 may exert its tumor suppressive effects in pancreatic cancer.

The hedgehog processing pathway is required for NSCLC growth and survival.

Considerable interest has been generated from the results of recent clinical trials using smoothened (SMO) antagonists to inhibit the growth of hedgehog (HH) signaling-dependent tumors. This interest is tempered by the discovery of SMO mutations mediating resistance, underscoring the rationale for developing therapeutic strategies that interrupt HH signaling at levels distinct from those inhibiting SMO function. Here, we demonstrate that HH-dependent non-small cell lung carcinoma (NSCLC) growth is sensitive to blockade of the HH pathway upstream of SMO, at the level of HH ligand processing. Individually, the use of different lentivirally delivered shRNA constructs targeting two functionally distinct HH-processing proteins, skinny hedgehog (SKN) or dispatched-1 (DISP-1), in NSCLC cell lines produced similar decreases in cell proliferation and increased cell death. Further, providing either an exogenous source of processed HH or a SMO agonist reverses these effects. The attenuation of HH processing, by knocking down either of these gene products, also abrogated tumor growth in mouse xenografts. Finally, we extended these findings to primary clinical specimens, showing that SKN is frequently overexpressed in NSCLC and that higher DISP-1 expression is associated with an unfavorable clinical outcome. Our results show a critical role for HH processing in HH-dependent tumors, identifies two potential druggable targets in the HH pathway, and suggest that similar therapeutic strategies could be explored to treat patients harboring HH ligand-dependent cancers.

DNA amplification is a ubiquitous mechanism of oncogene activation in lung and other cancers.

Chromosomal translocation is the best-characterized genetic mechanism for oncogene activation. However, there are documented examples of activation by alternate mechanisms, for example gene dosage increase, though its prevalence is unclear. Here, we answered the fundamental question of the contribution of DNA amplification as a molecular mechanism driving oncogenesis. Comparing 104 cancer lines representing diverse tissue origins identified genes residing in amplification 'hotspots' and discovered an unexpected frequency of genes activated by this mechanism. The 3431 amplicons identified represent approximately 10 per hematological and approximately 36 per epithelial cancer genome. Many recurrently amplified oncogenes were previously known to be activated only by disease-specific translocations. The 135 hotspots identified contain 538 unique genes and are enriched for proliferation, apoptosis and linage-dependency genes, reflecting functions advantageous to tumor growth. Integrating gene dosage with expression data validated the downstream impact of the novel amplification events in both cell lines and clinical samples. For example, multiple downstream components of the EGFR-family-signaling pathway, including CDK5, AKT1 and SHC1, are overexpressed as a direct result of gene amplification in lung cancer. Our findings suggest that amplification is far more common a mechanism of oncogene activation than previously believed and that specific regions of the genome are hotspots of amplification.

Differential disruption of cell cycle pathways in small cell and non-small cell lung cancer.

Lung cancer is the leading cause of cancer-related mortality in the world, with small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) comprising the two major cell types. Although these cell types can be distinguished readily at the histological level, knowledge of their underlying molecular differences is very limited. In this study, we compared 14 SCLC cell lines against 27 NSCLC cell lines using an integrated array comparative genomic hybridisation and gene expression profiling approach to identify subtype-specific disruptions. Using stringent criteria, we have identified 159 of the genes that are responsible for the different biology of these cell types. Sorting of these genes by their biological functions revealed the differential disruption of key components involved in cell cycle pathways. Our novel comparative combined genome and transcriptome analysis not only identified differentially altered genes, but also revealed that certain shared pathways are preferentially disrupted at different steps in these cell types. Small cell lung cancer exhibited increased expression of MRP5, activation of Wnt pathway inhibitors, and upregulation of p38 MAPK activating genes, while NSCLC showed downregulation of CDKN2A, and upregulation of MAPK9 and EGFR. This information suggests that cell cycle upregulation in SCLC and NSCLC occurs through drastically different mechanisms, highlighting the need for differential molecular target selection in the treatment of these cancers.

An outbreak of Mycobacterium terrae in clinical specimens associated with a hospital potable water supply.

We investigated an increase in the number of patient specimens yielding Mycobacterium terrae in 1986, isolation of M. terrae was associated with specimens obtained from inpatients at our new hospital, but not with specimens referred from other hospitals [37(+)/144 inpatient specimens versus 2(+)/26 referred specimens, p less than 0.05]. By October 31, 1987, we had identified 163 positive specimens from 131 patients. All M. terrae were isolated from specimens obtained from non-sterile sites, i.e., respiratory, gastrointestinal, or urine. No clinical disease related to M. terrae occurred. Review of procedures and cultures of solutions used in the Microbiology Laboratory suggested the source of M. terrae was not in the Microbiology Laboratory. An analysis of case location showed an association with hospital tier (p less than 0.05), a pattern matching the design of the potable water system of the hospital. M. terrae was cultured from multiple outlets of this system. There appeared to be multiple modes of transmission of M. terrae from this reservoir. Control measures included avoidance of water sources during specimen collection and hyperchlorination of the potable water system. These measures appeared to result in the disappearance of M. terrae from subsequent clinical specimens. We believe this to be the first report defining the epidemiologic aspects of M. terrae contaminating clinical specimens.