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EMAP-II-dependent lymphocyte killing is associated with hypoxia in colorectal cancer.

ABSTRACT: Endothelial-monocyte-activating polypeptide-II (EMAP-II) is a novel multifunctional polypeptide with proinflammatory activity. We have previously shown that the recombinant and native forms of EMAP-II can induce apoptosis in mitogen-stimulated lymphocytes, and that the release of this protein into the extracellular milieu is enhanced by hypoxia. We hypothesised that hypoxia may lead to death of tumour-infiltrating lymphocytes (TILs) via an EMAP-II-dependent mechanism, thereby assisting tumours to evade the immune system. In this study, we used immunohistochemistry to detect EMAP-II, active caspase-3 and cleaved Poly (ADP-ribose) Polymerase (PARP) as indicators of apoptosis in TILs, and carbonic anhydrase IX (CA IX) as a surrogate marker of hypoxia. EMAP-II expression is associated with regions of hypoxia, and furthermore there is a significant association between TILs apoptosis and the presence of hypoxia. Using a coculture model of colorectal cancer cell/lymphocyte interactions, we were also able to demonstrate lymphocyte apoptosis induced by tumour cells, with concomitant caspase-3 activity. Lymphocyte killing was enhanced by direct cell-cell contact, particularly by tumour cells exposed to hypoxic conditions. Our data support the hypothesis that hypoxia plays a role in immune evasion by tumour cells, through EMAP-II-dependent lymphocyte killing.

SUBMITTER: Youssef MM

PROVIDER: S-EPMC2360520 | biostudies-literature | 2006 Sep

REPOSITORIES: biostudies-literature

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EMAP-II-dependent lymphocyte killing is associated with hypoxia in colorectal cancer.

Youssef M M S MM Symonds P P Ellis I O IO Murray J C JC

British journal of cancer 20060822 6

Endothelial-monocyte-activating polypeptide-II (EMAP-II) is a novel multifunctional polypeptide with proinflammatory activity. We have previously shown that the recombinant and native forms of EMAP-II can induce apoptosis in mitogen-stimulated lymphocytes, and that the release of this protein into the extracellular milieu is enhanced by hypoxia. We hypothesised that hypoxia may lead to death of tumour-infiltrating lymphocytes (TILs) via an EMAP-II-dependent mechanism, thereby assisting tumours t ...[more]

PMID: 16929248

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Project description:BACKGROUND:Colorectal cancer (CRC) is the second leading cancer killer in the US today and patients with metastatic disease have only a 14% 5-year survival. One of the most impactful recent advances in cancer therapy, immune checkpoint inhibition, has not been shown to be effective for the majority of these patients. In this study, we use The Cancer Genome Atlas (TCGA) and recently developed informatic-based tools to identify targets for immune based therapy in colorectal cancer patients. METHODS:Open access, pre-processed (level 3) mRNA data and clinical data from colorectal patients from the TCGA was downloaded from FireCloud. Using the Microenvironment Cell Populations-Counter method (MCP-Counter), cytotoxic lymphocyte scores were calculated for all patients. Patients were then grouped by cytotoxic lymphocyte score (High vs Low), pathologic stage, and location to identify differentially expressed genes. Pathway enrichment analysis was performed using Reactome to determine differentially expressed genes associated with immune pathways. Survival analysis was performed with identified differentially expressed genes. RESULTS:In the TCGA dataset, there are 461 colon and 172 rectal cancer patients. After stratifying patients by cytotoxic lymphocyte score, anatomical location, and stage, we found a significant number of differentially expressed genes. We identified one pathway, "immunoregulatory interactions between a lymphoid and non-lymphoid cell", that was highly enriched and included in all tumor locations and stages. Survival analysis performed with differentially expressed genes in this pathway identified 21 different genes associated with survival and cytotoxic lymphocyte infiltration, with ~?70% of these genes occurring in the metastatic right-sided CRC group. Specifically, all genes associated with survival in the metastatic right-sided colorectal cancer group with low cytotoxic lymphocyte scores positively impacted survival. CONCLUSIONS:Utilizing the TCGA, a publicly available dataset, and informatics-based analyses, we identified potential targets to improve immune based therapy in colorectal cancer. Additionally, we note the most targets in metastatic right-sided CRC patients, the patient group with the worst predicted survival. The results from this study demonstrate the ability of informatics-based analytic techniques to identify new therapeutic targets as well as improve patient selection for intervention, helping us to achieve the goals of precision-based oncology.

Project description:BackgroundHypoxic microenvironments play a significant role in the progression of colorectal cancer (CRC). Silencing information regulator 1 (SIRT1), a class III histone deacetylase, modulates the multiple biological behaviors of cancer. However, its role in CRC remains unclear. This study aims to explore the role of SIRT1 in CRC migration and invasion under hypoxia.MethodsSIRT1 protein and mRNA levels were detected by Western blotting and real-time PCR in CRC cells exposed to hypoxia (1% O2). The migration and invasion abilities of SW480 and HCT116 cells with SIRT1 overexpression or knockdown were studied with transwell assays, and the results were confirmed by those of treatment with specific SIRT1 activator (SRT1720) and inhibitor (EX527). The dual-luciferase reporter systems with a series of SIRT1 promoter truncations were used to analyze their transcriptional activities, respectively. After a bioinformatic analysis of potential transcription factors, the direct interaction between the transcription factor and SIRT1 promoter was determined by chromatin immunoprecipitation (ChIP) assays. Western blot and real-time PCR assays were used to detect the activation and acetylation levels of the NF-κB pathway.ResultsThe protein and mRNA levels of SIRT1 were significantly decreased under hypoxia, and these effects were replicated by cobalt chloride treatment. Hypoxia promoted cell migration and invasion, which were impeded by the overexpression or activation of SIRT1 and promoted by the knockdown or inhibition of SIRT1. The dual-luciferase reporter gene and ChIP analyses revealed that the core regulatory elements located 100 bp upstream of the SIRT1 promoter and early growth response factor 1 (EGR1) could interact with this DNA sequence. Subsequent rescue experiments suggested that EGR1 was essential for hypoxia-mediated SIRT1 transcriptional suppression. Western blot analyses demonstrated that SIRT1 overexpression eliminated the p65 acetylation induced by hypoxia along with the decreased MMP-2/-9, suggesting that NF-κB was a direct downstream target of SIRT1 and might regulate cell migration and invasion through MMP-2/-9.ConclusionsOur results establish for the first time that EGR1 plays an important role in regulating SIRT1 expression under hypoxia. Hypoxia promotes CRC cell migration and invasion in a SIRT1-dependent manner. And a potential SIRT1/NF-κB/MMP-2/-9 axis modulates this process.

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EMAP-II-dependent lymphocyte killing is associated with hypoxia in colorectal cancer.

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EMAP-II-dependent lymphocyte killing is associated with hypoxia in colorectal cancer.

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