Preliminary characterization of IL32 in basal-like/triple negative compared to other types of breast cell lines and tissues

Abstract

BackgroundTriple negative breast cancer (TNBC) and often basal-like cancers are defined as negative for estrogen receptor, progesterone receptor and Her2 gene expression. Over the past few years an incredible amount of data has been generated defining the molecular characteristics of both cancers. The aim of these studies is to better understand the cancers and identify genes and molecular pathways that might be useful as targeted therapies. In an attempt to contribute to the understanding of basal-like/TNBC, we examined the Gene Expression Omnibus (GEO) public datasets in search of genes that might define basal-like/TNBC. The Il32 gene was identified as a candidate.FindingsAnalysis of several GEO datasets showed differential expression of IL32 in patient samples previously designated as basal and/or TNBC compared to normal and luminal breast samples. As validation of the GEO results, RNA and protein expression levels were examined using MCF7 and MDA MB231 cell lines and tissue microarrays (TMAs). IL32 gene expression levels were higher in MDA MB231 compared to MCF7. Analysis of TMAs showed 42% of TNBC tissues and 25% of the non-TNBC were positive for IL32, while non-malignant patient samples and all but one hyperplastic tissue sample demonstrated lower levels of IL32 protein expression.ConclusionData obtained from several publically available GEO datasets showed overexpression of IL32 gene in basal-like/TNBC samples compared to normal and luminal samples. In support of these data, analysis of TMA clinical samples demonstrated a particular pattern of IL32 differential expression. Considered together, these data suggest IL32 is a candidate suitable for further study.

Analyses of the Interleukin32 Transcript Variants in Breast Cancer Cell Lines

“…Based on their differential expression in the breast cell lines, the primer sets are ranked as primer set 1>primer set 5>primer set 2>primer set 4>primer set 3. Overall, the PCR analysis and densitometer readings validate what we observed in the cell lines and patient samples (Player et al, 2014), in that IL32 is differentially expressed in the cell lines and even though their levels vary, several transcript variants contribute to the differential pattern of expression observed in these samples.…”

“…Park et al (2013) found that over expression of IL32β correlated with tumor progression in breast cells, however, compared to other tissues, less is known about IL32 in breast samples. Although their study show that luminal and TNBC cell types express IL32 gene, studies in our laboratory demonstrate substantial differential gene expression of IL32 in basal-like/TNBCs compared to normal and luminal breast cancer cell lines and patient samples (Player et al, 2014). Since our initial observations, we have performed studies to better characterize the IL32 gene in breast cancers.…”

“…We previously showed that IL32 was differentially expressed in basal-like/TNBC compared to normal and luminal breast cancer cell lines and clinical samples (Player et al, 2014). For the current study, our goal was to better characterize the transcript variants responsible for the differential pattern of gene expression observed in those samples.…”

Constitutive activation of STAT3 in breast cancer cells: A review

“…IL‐32β is a pro‐inflammatory cytokine that induces secretion of TNF‐α and IL‐6 by monocytes and macrophages . Immunohistochemical (IHC) analysis of primary BC samples showed that the expression of IL‐32β positively correlated with tumor size, number of lymph nodes, metastases and tumor stage .…”

Identification of Genes Differentially Associated with Triple Negative Breast Cancers

“…An outline of our approach is given in Table1. As summary, we previously retrieved TNBC DNA microarray datasets from Gene Expression Omnibus and found thatIL32 cytokine was differentially expressed in some, not all TNBC cell lines and patient samples (18). Cytokines are immune-modulating proteins involved in both immune and epithelial cell signaling events.…”