Long Non-Coding RNA Expression in Laser Micro-Dissected Luminal A and Triple Negative Breast Cancer Tissue Samples-A Pilot Study.

Background and Objectives: Breast cancer (BC) remains one of the major causes of cancer death in women worldwide. The difficulties in assessing the deep molecular mechanisms involved in this pathology arise from its high complexity and diverse tissue subtypes. Long non-coding RNAs (lncRNAs) were shown to have great tissue specificity, being differentially expressed within the BC tissue subtypes. Materials and Methods: Herein, we performed lncRNA profiling by PCR array in triple negative breast cancer (TNBC) and luminal A tissue samples from 18 BC patients (nine TNBC and nine luminal A), followed by individual validation in BC tissue and cell lines. Tissue samples were previously archived in formalin-fixed paraffin-embedded (FFPE) samples, and the areas of interest were dissected using laser capture microdissection (LCM) technology. Results: Two lncRNAs (OTX2-AS1 and SOX2OT) were differentially expressed in the profiling analysis (fold change of 205.22 and 0.02, respectively, p < 0.05 in both cases); however, they did not reach statistical significance in the individual validation measurement (p > 0.05) when analyzed with specific individual assays. In addition, GAS5 and NEAT1 lncRNAs were individually assessed as they were previously described in the literature as being associated with BC. GAS5 was significantly downregulated in both TNBC tissues and cell lines compared to luminal A samples, while NEAT1 was significantly downregulated only in TNBC cells vs. luminal A. Conclusions: Therefore, we identified GAS5 lncRNA as having a differential expression in TNBC tissues and cells compared to luminal A, with possible implications in the molecular mechanisms of the TNBC subtype. This proof of principle study also suggests that LCM could be a useful technique for limiting the sample heterogeneity for lncRNA gene expression analysis in BC FFPE tissues. Future studies of larger cohort sizes are needed in order to assess the biomarker potential of lncRNA GAS5 in BC.

Molecular profiling of ADAM12 gene in breast cancers.

ADAMs (a disintegrin and metalloproteinase) family have been associated with the process of proteolytic "shedding" of membrane-associated proteins ectodomain and hence the rapid modulation of key cell signaling pathways in tissues microenvironment. A variety of cytokines, chemokines and growth factors which are initially produced as transmembrane proforms are activated by these sheddase activities. ADAM12 is highly expressed in rapidly growing tissues such as placenta and malignant tumors and it was found as one of the Candidate Cancer Genes in a comprehensive mutational analysis of human breast cancers. Our aim was to determine the gene expression profile of ADAM12 in breast cancers in comparison with normal breast and to correlate their level of expression with the clinical and pathological characteristics of breast cancers. Gene expression of ADAM12 spliced variants (12L and 12S) was evaluated using quantitative reverse-transcription PCR in samples obtained by laser capture microdissection from 38 patients with breast cancers and compared with adjacent healthy breast tissues. Both ADAM12L and 12S expression were significantly up-regulated in breast cancers, while in the normal breast, we found a very low expression. ADAM12L expression was significantly correlated with the histopathological types and, although not statistically significant, ADAM12 both variants were up-regulated in high-grade, highly-proliferative and HER2÷neu positive tumors. From these preliminary results, we found that ADAM12 could be an interesting marker and eventually a therapeutic target for breast cancer.

MicroRNA Expression in Laser Micro-dissected Breast Cancer Tissue Samples - a Pilot Study.

Breast cancer continues to represent a significant public health burden despite outstanding research advances regarding the molecular mechanisms of cancer biology, biomarkers for diagnostics and prognostic and therapeutic management of this disease. The studies of micro RNAs in breast cancer have underlined their potential as biomarkers and therapeutic targets; however most of these studies are still done on largely heterogeneous whole breast tissue samples. In this pilot study we have investigated the expression of four micro RNAs (miR-21, 145, 155, 92) known to be involved in breast cancer, in homogenous cell populations collected by laser capture microdissection from breast tissue section slides. Micro RNA expression was assessed by real time PCR, and associations with clinical and pathological characteristics were also explored. Our results have confirmed previous associations of miR-21 expression with poor prognosis characteristics of breast cancers such as high stage, large and highly proliferative tumors. No statistically significant associations were found with the other micro RNAs investigated, possibly due to the small sample size of our study. Our results also suggest that miR-484 could be a suitable endogenous control for data normalization in breast tissues, these results needing further confirmation by future studies. In summary, our pilot study showed the feasibility of detecting micro RNAs expression in homogenous laser captured microdissected invasive breast cancer samples, and confirmed some of the previously reported associations with poor prognostic characteristics of breast tumors.

Molecular profiling of ADAM12 and ADAM17 genes in human malignant melanoma.

ADAM12 and ADAM17 proteins belong to a family of transmembrane disintegrin-containing metalloproteinases (ADAMs) involved in the proteins ectodomain shedding and cell-cell and cell-matrix interactions. However, the specific biological functions of ADAMs are still unclear and, until now, these proteins were not investigated yet in melanoma. The aim of this study was to analyze the splicing variants of ADAM12 (L and S) and ADAM17 gene expression in melanoma at transcriptional and translational level in comparison with control (non-tumor) tissues. Taking in account that ADAM17 sheddase is involved in the modulation of TNF-α (tumor necrosis factor alpha), we analyzed also this cytokine in the plasma of the same patients before any treatment, and we compared the results with healthy controls. Quantitative-RT-PCR and immunohistochemistry were used to analyze ADAM12 and ADAM17 genes expression and the analysis of TNF-α expression was carried out in the plasma using ELISA. We demonstrated that ADAM12L splicing variant together with ADAM17 gene are strongly overexpressed in melanomas, whereas ADAM12S, although up-regulated when compared with the non-tumor controls, the difference was not statistically significant. When we compared the levels of expression for the ADAMs genes according to the tumor stage, we observed that all three investigated genes were significantly overexpressed in advanced stage in comparison with early stage melanomas. In the plasma of the same patients, the expression of TNF-α was up-regulated and significantly correlated with the expression of ADAM17 and respectively, with the advanced tumor stage.

ADAM12 and ADAM17 gene expression in laser-capture microdissected and non-microdissected breast tumors.

ADAM (a disintegrin and metalloprotease)12 and ADAM17 are multidomain transmembrane proteins involved in ectodomain shedding of cytokines, growth factors and adhesion molecules, with pivotal activities in the tumor microenvironment. The aim of this study was to confirm the up-regulation of ADAM17 and ADAM12 gene splicing variants in breast tumors and to delineate their expression between laser-capture microdissected (LCM) and non-microdissected breast tumors. The gene expression was analyzed by quantitative-reverse transcription-PCR in a total sample of 109 breast tumors paired with corresponding non-neoplastic breast tissues. ADAM12 and 17 proteins expression for corresponding tissue samples was confirmed by immunohistochemistry. ADAM12S, 12L and 17 genes were significantly up-regulated in either malign or benign LCM samples when compared to non-tumor controls. For non-LCM samples, it was obtained also an increased expression for ADAM12 and 17 genes in cancers, while in benign tumors only ADAM12 variants were significantly up-regulated compared to controls. When benign versus malignant tumors were compared, in LCM samples all investigated genes displayed a higher expression in cancers, whereas in non-LCM, ADAM12 variants were overexpressed in benign samples. The increased expression of ADAM12 protein in the tumor cells and stroma of benign breast diseases was immunohistochemically confirmed. These differences between LCM and non-LCM samples were explained by the contribution of the stroma to the expression of this marker. This study underlines the accuracy conferred by homogenous LCM samples on gene expression profiles and confers further evidence regarding the role of ADAM12 and 17 in the breast tumorigenesis and progression.

Expression of CCL18 and interleukin-6 in the plasma of breast cancer patients as compared with benign tumor patients and healthy controls.

A growing body of laboratory research has shown that pro-inflammatory cytokines can facilitate tumor growth and metastasis. Our goal was to quantify the expression of CCL18 and IL-6 in patients with breast cancer compared with benign breast tumors patients and healthy women, in order to evaluate if these cytokines could serve for breast cancer diagnosis and evaluation. We also correlated the cytokines level of expression with some clinical and pathological characteristics known as prognostic markers for breast cancer. Plasma samples were obtained before treatment from 58 breast cancers, 41 benign breast tumors and 30 healthy women. The quantitative dosage was performed using ELISA. Wilcoxon test was used to compare groups. IL-6 and CCL18 were dramatically upregulated in breast cancers in comparison with healthy controls, but in comparison with benign tumors only CCL18÷PARC was overexpressed at borderline significance in cancers (p=0.05). The plasma from benign breast tumor patients exhibited also significant higher levels of the two cytokines than normal controls. The cytokines profile was not linked to patient age, tumor size, histopathological type, lymph node status or histological grade. IL-6 was significantly upregulated in ER-positive and metastasized cancers. CCL18÷PARC presented a significantly higher expression in advanced stage and highly proliferative carcinomas. In summary, IL-6 and CCL18 could clearly distinguish between women with breast cancers and healthy controls. High expression of IL-6 seems to confer a poor prognosis for ER-positive cancers. CCL18 was associated with worse prognosis parameters like high Ki67.