CCL2-Mediated Stromal Interactions Drive Macrophage Polarization to Increase Breast Tumorigenesis.

CCL2 is an inflammatory cytokine that regulates macrophage activity and is implicated in increased mammographic density and early breast tumorigenesis. The role of CCL2 in mediating stromal interactions that contribute to breast tumorigenesis has yet to be fully elucidated. THP-1-derived macrophages and mammary fibroblasts were co-cultured for 72 h. Fibroblasts and macrophages were analysed for phenotype, expression of inflammatory and ECM-regulatory genes and collagen production. Mice overexpressing CCL2 in the mammary glands were analysed for global gene expression by RNAseq at 12 weeks of age. These mice were cross-bred with PyMT mammary tumour mice to examine the role of CCL2 in tumorigenesis. The co-culture of macrophages with fibroblasts resulted in macrophage polarization towards an M2 phenotype, and upregulated expression of CCL2 and other genes associated with inflammation and ECM remodelling. CCL2 increased the production of insoluble collagen by fibroblasts. A global gene expression analysis of CCL2 overexpressing mice revealed that CCL2 upregulates cancer-associated gene pathways and downregulates fatty acid metabolism gene pathways. In the PyMT mammary tumour model, CCL2 overexpressing mice exhibited increased macrophage infiltration and early tumorigenesis. Interactions between macrophages and fibroblasts regulated by CCL2 can promote an environment that may increase breast cancer risk, leading to enhanced early tumorigenesis.

A Method for Next-Generation Sequencing of Paired Diagnostic and Remission Samples to Detect Mitochondrial DNA Mutations Associated with Leukemia.

Somatic mitochondrial DNA (mtDNA) mutations have been identified in many human cancers, including leukemia. To identify somatic mutations, it is necessary to have a control tissue from the same individual for comparison. When patients with leukemia achieve remission, the remission peripheral blood may be a suitable and easily accessible control tissue, but this approach has not previously been applied to the study of mtDNA mutations. We have developed and validated a next-generation sequencing approach for the identification of leukemia-associated mtDNA mutations in 26 chronic myeloid leukemia patients at diagnosis using either nonhematopoietic or remission blood samples as the control. The entire mt genome was amplified by long-range PCR and sequenced using Illumina technology. Variant caller software was used to detect mtDNA somatic mutations, and an empirically determined threshold of 2% was applied to minimize false-positive results because of sequencing errors. Mutations were called against both nonhematopoietic and remission controls: the overall concordance between the two approaches was 81% (73/90 mutations). Some discordant results were because of the presence of somatic mutations in remission samples, because of either minimal residual disease or nonleukemic hematopoietic clones. This method could be applied to study somatic mtDNA mutations in leukemia patients who achieve minimal residual disease, and in patients with nonhematopoietic cancers who have a matched uninvolved tissue available.

MicroRNA signatures in chemotherapy resistant esophageal cancer cell lines.

AIM: To investigate expression of microRNA (miRNA) and potential targets in chemotherapy resistant esophageal cancer cell lines. METHODS: An in-vitro model of acquired chemotherapy resistance in esophageal adeno- (EAC) and squamous cell carcinoma (ESCC) cells was used, and microRNA expression profiles for cisplatin or 5-fluorouracil (5-FU) resistant variants vs chemotherapy sensitive controls were compared using microarray and quantitative real-time polymerase chain reaction (PCR). The expression of chemotherapy-relevant genes potentially targeted by the dysregulated microRNAs in the chemotherapy resistant variants was also evaluated. RESULTS: Chemotherapy resistant sublines were found to have specific miRNA signatures, and these miRNA signatures were different for the cisplatin vs 5-FU resistant cells from the same tumor cell line, and also for EAC vs ESCC cells with resistance to the same specific chemotherapy agent. Amongst others, miR-27b-3p, miR-193b-3p, miR-192-5p, miR-378 a-3p, miR-125a-5p and miR-18a-3p were dysregulated, consistent with negative posttranscriptional control of KRAS, TYMS, ABCC3, CBL-B and ERBB2 expression via these miRNAs. CONCLUSION: The current study supports the hypothesis that microRNA expression has an impact on chemotherapy resistance in esophageal cancer.

Histone deacetylase inhibition in colorectal cancer cells reveals competing roles for members of the oncogenic miR-17-92 cluster.

Diet-derived butyrate, a histone deacetylase inhibitor (HDI), decreases proliferation and increases apoptosis in colorectal cancer (CRC) cells via epigenetic changes in gene expression. Other HDIs such as suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA) have similar effects. This study examined the role of microRNAs (miRNAs) in mediating the chemo-protective effects of HDIs, and explored functions of the oncogenic miR-17-92 cluster. The dysregulated miRNA expression observed in HT29 and HCT116 CRC cells could be epigenetically altered by butyrate, SAHA and TSA. These HDIs decreased expression of miR-17-92 cluster miRNAs (P < 0.05), with a corresponding increase in miR-17-92 target genes, including PTEN, BCL2L11, and CDKN1A (P < 0.05). The decrease in miR-17-92 expression may be partly responsible for the anti-proliferative effects of HDIs, with introduction of miR-17-92 cluster miRNA mimics reversing this effect and decreasing levels of PTEN, BCL2L11, and CDKN1A (P < 0.05). The growth effects of HDIs may be mediated by changes in miRNA activity, with down-regulation of the miR-17-92 cluster a plausible mechanism to explain some of the chemo-protective effects of HDIs. Of the miR-17-92 cluster miRNAs, miR-19a and miR-19b were primarily responsible for promoting proliferation, while miR-18a acted in opposition to other cluster members to decrease growth. NEDD9 and CDK19 were identified as novel miR-18a targets and were shown to be pro-proliferative genes, with RNA interference of their transcripts decreasing proliferation in CRC cells. This is the first study to identify competing roles for miR-17-92 cluster members, in the context of HDI-induced changes in CRC cells.

Efficacy and mechanisms of action of vitamin D in experimental polyarthritis.

Vitamin D (vit D) status has been linked to the occurrence and severity of auto-immune and inflammatory diseases. This study evaluates the effects of vit D status on adoptive transfer of adjuvant-induced arthritis (ATA). Rats maintained on diets replete or deficient in vit D3 received arthritogenic thoracic duct cells and were monitored for severity of arthritis. CD45(+) cells obtained by collagenase digestion of hind-paw synovium-rich tissues (SRTs) were analysed to observe the effects of dietary vit D3 on the inflammatory process. Arthritis was more severe in vitamin D-deficient (vit-D(-)) rats compared with vitamin D-replete (vit-D(+)) rats. Resolution was delayed in vit-D(-) rats compared with vit-D(+) rats, or rats fed standard chow. During the acute phase of ATA, numbers of CD45(+) cells were significantly increased in the SRTs of vit-D(-) rats compared with vit-D(+) rats. This increase involved T-cells, polymorphonuclear leukocytes, macrophages, dendritic cells (DCs) and MHC II(hi) cells that resemble activated monocytes. A major difference between the dietary groups was that most DCs at the peak of inflammation in vit-D(-) rats were CD4(-), whereas in convalescent vit-D(+) rats most expressed CD4. Multiple categories of genes expressed by DCs differed between deficient and replete rats, with deficiency being associated with relative upregulation of certain pro-inflammatory genes and replete status being associated with upregulation of genes associated with resolution of inflammation. The findings indicate that ATA is more severe and prolonged in vit-D deficiency, that vit-D deficiency promotes accumulation of CD4(-) DCs in synovium during ATA and that a gene-expression profile is likely to contribute to the observed increased severity and duration of arthritis.

Chemotherapy-induced modification of microRNA expression in esophageal cancer.

Neoadjuvant chemotherapy is often used in the treatment of advanced esophageal cancer. In this study, we determined the impact of chemotherapy on microRNA (miRNA) expression in esophageal cancer cells, and whether identified changes might have biological relevance. Two esophageal carcinoma cell lines (one adenocarcinoma and one squamous cell carcinoma) were treated with cisplatin or 5-fluorouracil for 24 or 72 h. RNA was extracted from cells following 24-h treatment, and used for microarray studies. Promising miRNA candidates were selected for RT-PCR validation. Target prediction using TargetScan, combined with bioinformatic analysis (Ingenuity Pathway Analysis, IPA), was performed to evaluate the implications of the altered miRNA expression. Thirteen miRNAs (miR-199a-5p, miR-302f, miR-320a, miR-342-3p, miR-425, miR-455-3p, miR-486-3p, miR-519c-5p, miR-548d-5p, miR-617, miR-758, miR-766, miR-1286) were deregulated after 24- and/or 72-h treatment in both cell lines, and most miRNAs presented similar expression changes after short- or long-term exposure. IPA revealed that the major networks which incorporate the predicted targets, include functions such as 'Cell death', 'Cell cycle', 'Cellular growth and proliferation', 'DNA replication, recombination, and repair' and 'Drug metabolism'. Cisplatin or 5-fluorouracil alter miRNA expression in esophageal cancer cells. IPA suggests that these miRNAs may target molecular pathways involved in cell survival after chemotherapy.

The VHL-dependent regulation of microRNAs in renal cancer.

BACKGROUND: The commonest histological type of renal cancer, clear cell renal cell carcinoma (cc RCC), is associated with genetic and epigenetic changes in the von Hippel-Lindau (VHL) tumour suppressor. VHL inactivation leads to induction of hypoxia-inducible factors (HIFs) and a hypoxic pattern of gene expression. Differential levels of specific microRNAs (miRNAs) are observed in several tumours when compared to normal tissue. Given the central role of VHL in renal cancer formation, we examined the VHL-dependent regulation of miRNAs in renal cancer. METHODS: VHL-dependent miRNA expression in cc RCC was determined by microarray analysis of renal cell line RCC4 with mutated VHL (RCC4-VHL) and reintroduced wild-type VHL (RCC4 + VHL). Five miRNAs highly upregulated in RCC4 + VHL and five miRNAs highly downregulated in RCC4 + VHL were studied further, in addition to miR-210, which is regulated by the HIF-VHL system. miRNA expression was also measured in 31 cc RCC tumours compared to adjacent normal tissue. RESULTS: A significant increase in miR-210, miR-155 and miR-21 expression was observed in the tumour tissue. miR-210 levels also showed a correlation with a HIF-regulated mRNA, carbonic anhydrase IX (CAIX), and with VHL mutation or promoter methylation. An inverse correlation was observed between miR-210 expression and patient survival, and a putative target of miR-210, iron-sulfur cluster assembly protein (ISCU1/2), shows reciprocal levels of mRNA expression in the tumours. CONCLUSIONS: We have identified VHL-regulated miRNAs and found that for some the regulation is HIF-dependent and for others it is HIF-independent. This pattern of regulation was also seen in renal cancer tissue for several of these miRNAs (miR-210, miR-155, let-7i and members of the miR-17-92 cluster) when compared with normal tissue. miR-210 showed marked increases in expression in renal cancer and levels correlated with patient survival. The inverse correlation between miR-210 levels and ISCU1/2 provides support for the hypothesis that ISCU1/2 is a target of miR-210 and that it may contribute to the anaerobic respiration seen in renal (and other) tumours.See Commentary: http://www.biomedcentral.com/1741-7015/8/65.

The interleukin-6 family cytokine interleukin-11 regulates homeostatic epithelial cell turnover and promotes gastric tumor development.

BACKGROUND & AIMS: Gastric cancer is the second most common cause of cancer-related mortality worldwide, mainly as a result of late-stage detection. Interleukin (IL)-11 is a multifunctional cytokine reported to be up-regulated in human gastric cancer. METHODS: We investigated the importance of IL-11 in gastric cancer progression by examining its role in a variety of mouse gastric tumor models, as well as in nonneoplastic and tumor tissues taken from gastric cancer patients. We then determined the transcriptional and translational outcomes of IL-11 overexpression in normal gastric mucosa and identified a novel gene signature important early in the progression toward gastric tumorigenesis. RESULTS: IL-11 was up-regulated significantly in 4 diverse mouse models of gastric pathology as well as in human biopsy specimens adjacent to and within gastric cancer. Removal of IL-11 co-receptor alpha significantly reduced HKbeta-/- mouse fundic hyperplasia and ablated gp130(757F/F) mouse tumorigenesis. Exogenous IL-11 but not IL-6 activated oncogenic signal transducer and activator of transcription-3, and altered expression of novel proliferative and cytoprotective genes RegIII-beta, RegIII-gamma, gremlin-1, clusterin, and growth arrest specific-1 in wild-type gastric mucosa, a gene signature common in gp130(757F/F) and HKbeta-/- tumors as well as nonneoplastic mucosa of gastric cancer patients. One week of chronic IL-11 administration in wild-type mice sustained the gene signature, causing pretumorigenic changes in both antrum and fundus. CONCLUSIONS: Increased gastric IL-11 alters expression of proliferative and cytoprotective genes and promotes pretumorigenic cellular changes.