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Breast cancer is a heterogeneous disease comprising the estrogen receptor (ER)–positive luminal subtype which is subdivided into luminal A and luminal B and ER-negative breast cancer which includes the triple-negative subtype. This study has four aims: 1) to examine whether Minichromosome Maintenance (MCM)2, MCM4, and MCM6 can be used as markers to differentiate between luminal A and luminal B subtypes; 2) to study whether MCM2, MCM4, and MCM6 are highly expressed in triple-negative breast cancer, as there is an urgent need to search for surrogate markers in this aggressive subtype, for drug development purposes; 3) to compare the prognostic values of these markers in predicting relapse-free survival; and 4) to compare the three approaches used for scoring the protein expression of these markers by immunohistochemistry (IHC). MCM2, MCM4, MCM6, and MKI67 mRNA expression was first studied using in silico analysis of available breast cancer datasets. We next used IHC to evaluate their protein expression on tissue microarrays using three scoring methods. MCM2, MCM4, and MCM6 can help in distinction between luminal A and luminal B whose therapeutic management and clinical outcomes are different. MCM2, MCM4, MCM6, and Ki-67 are highly expressed in breast cancer of high histological grades that comprise clinically aggressive tumors such as luminal B, HER2-positive, and triple-negative subtypes. Low transcript expression of these markers is associated with increased probability of relapse-free survival. A positive relationship exists among the three scoring methods of each of the four markers. An independent validation cohort is needed to confirm their clinical utility.

miRNAs, a group of short noncoding RNAs, are key regulators of fundamental cellular processes and signaling pathways. Dysregulation of miRNA expression with known oncogenic or tumor suppressor functions has been associated with neoplastic transformation. Numerous studies have reported dysregulation of miRNA-141, miR-181b1, and miR-23b in a wide range of malignancies, including breast cancer. To the best of our knowledge, no previous study had demonstrated the expression of miR-141-3p, miR-181b1-5p, and miR-23b-3p in different histological grades and molecular subtypes of breast cancer. Here, we identified differential expression of these three miRNAs in breast cancer tissues compared with benign breast fibroadenomas. In addition, high expression levels of miR-141-3p and miR-181b1-5p are strongly associated with aggressive breast carcinomas. We also confirmed the clinical potential of using the three miRNAs individually or combined as diagnostic and prognostic markers in breast cancer. Using bioinformatics analyses, we identified 23 hub genes of these three miRNAs which are involved in key signaling pathways in breast cancer. Furthermore, the KM plotter online database analysis demonstrates the association between elevated expression of miR-141 and miR-181b and shorter overall survival of breast cancer patients. Together, our data suggest an oncogenic role of the studied miRNAs and highlight their molecular roles and potential clinical applications in breast cancer.

Introduction: miR-34a has been recently introduced to clinical trials especially in breast cancer depending on its crucial role as microRNA suppressor tumors since it regulates several oncogenes. We explore here the prognostic effect of miR-34a on triple negative breast cancer (TNBC) overall survival compared to no triple negative (NTNBC) group and its effect on PARP-1 and BRCA1 protein expression. Methods: 76 patients with TNBC and NTNBC were recruited for this study. miR-34a was quantified using qPCR Syber Green technique. PARP-1 and BRCA1 were analyzed by IHC using Tissue Micro-Array method. Results: PARP-1 is more expressed in TNBC compared to NTNBC; P = 0.04; RR= 1.8 (1.1-3.1), however, BRCA1 is less expressed in TNBC; P = 0.03; RR= 2 (1.2-12.6). Furthermore, we evaluated the relationship between miR-34a and clinicopathological features with survival rate of both studied groups, we found that miR-34a is more expressed among patients with distance metastases in TNBC group P = 0.001; RR = 6.5 (2.1-19.6). Survival analysis showed that miR-34a low expression in TNBC was remarkably related to overall survival; P=0.012. Furthermore, multivariate survival test suggested that the absence of miR-34a was linked to the poor survival within TNBC according to the presence of distance metastasis; P=0.048; HR= 2.69. Our results showed that miR-34a is decreased in triple negative breast cancer patients with a very poor prognosis. Conclusion:Our results give mechanistic insights in miR-34a as a prognostic biomarker for overall survival Triple Negative Breast Cancer within Tunisian patients through its effect on PARP-1 and BRCA1 protein expression which may open potential new strategies towards prevention and therapeutic inhibition of PARP-1 positive within mammary tumors. Citation Format: Medimegh I, Ayari H, Baraudi O, Majoul H, Omrane I, Yousef E, Benayed F, Benromdhan K, Gaboury L, Mader S, Benammarelgaaied A. miR-34a as a prognostic biomarker for overall survival triple negative breast cancer within Tunisian patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-07-12.

International audience; Because of their ability to induce local immunosuppression and to confer cancer cells with resistance to apoptosis, members of the galectin family are emerging as a new class of actionable targets in cancer. Unfortunately, we have yet to obtain a clear picture of the galectin signatures in cancer cells and the surrounding tumor microenvironment. The aim of this study was to provide the first detailed analysis of the galectin signature in molecular subtypes of breast cancer. Expression signatures of galectins were obtained at the mRNA and protein levels. A particular attention was paid to stromal versus epithelial staining and to subcellular compartmentalization. Analysis of the stromal signature showed that gal-1, -3, -9-positive stroma were preferentially found in triple-negative (TN) and HER2 subtypes. In cancer cells, gal-1, -3, -8, and -9 showed a dual expression pattern, being found either in the cytosol or in the cytosol and the nucleus. TN patients with gal-8-positive nuclei had significantly better disease-free survival (DFS), distant-disease-free survival (DDFS), and overall survival (OS). In contrast, high expression of nuclear gal-1 correlated with poor DDFS and OS. TNBC patients who were positive for both nuclear gal-1 and gal-8 had 5-year DFS and DDFS of 100%, suggesting a dominance of the gal-8 phenotype. Overall, the results indicate that specific galectin expression signatures contribute to the phenotypic heterogeneity of aggressive subtypes of breast cancer. Our data also suggest that galectins have clinical utility as indicators of disease progression and therapeutic targets in aggressive molecular subtypes of breast cancer.

Despite recent advances in breast cancer therapeutics, mortality of metastatic triple negative breast cancer (TNBC) subtype remains high; due to their lack of hormone receptors expression for targeted therapy. Aberrant activation of Wnt/β-catenin signaling has been associated with breast cancers; where 40% of total breast cancers have elevated β-catenin levels with increased Wnt activity. Recently, we identified DEAD-box RNA helicase DP103 as a novel prognostic biomarker and metastasis-driving oncogene; highly expressed in TNBC subtype. Interestingly, we found high DP103 expression to be positively correlated with high β-catenin expression in clinical specimens (n=400). This led us to hypothesize a possible role of DP103 in modulating the Wnt/β-catenin pathway in TNBCs. Depletion of DP103 in metastatic TNBC cells decreases Wnt/β-catenin activity and expression of downstream Wnt target genes, while overexpression of DP103 increases Wnt activity. Depletion of DP103 also decreases phosphorylation of LRP6 and several important Wnt modulators required for downstream Wnt activation. Moreover, induction of Wnt/β-catenin signaling in Wnt responsive TNBC cells also significantly increased DP103 expression, indicating a possible positive feedback loop. Both canonical and non-canonical Wnt signaling is known to independently promote stem cell growth in mammospheres. Herein, we will also provide evidence on the role of DP103 in promoting breast cancer stem cell-like properties. Collectively, our data show a novel regulatory role of DP103 in the Wnt/β-catenin signaling pathway and in promoting breast cancer stem cell-like behavior, presenting itself as a potential drug target in TNBC patients. Citation Format: Cai W, Cheong JK, Edison E, Banerjee A, Tan TZ, Gaboury L, Yousef EM, Thiery JP, Lobie PE, Virshup DM, Yap CT, Kumar AP. DEAD-box RNA helicase DP103 as a novel regulator of Wnt/β-catenin signaling pathway and promotes cancer stem cell-like behavior in triple negative breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-08-03.

Phospholipase A2 receptor 1 (PLA2R1) expression and its role in the initiation and progression of breast cancer are an unresolved issue. PLA2R1 was found to endorse several tumor suppressive responses, including cellular senescence and apoptosis. Previous in vitro studies demonstrated that DNA hypermethylation was highly associated with the epigenetic silencing of PLA2R1 in breast cancer cell lines. Our objective was to study the level of PLA2R1 mRNA expression and the methylation of its promoter in different histological grades and molecular subtypes of breast cancer. We performed bioinformatics analyses on available human breast cancer expression datasets to assess the PLA2R1 mRNA expression. We used qRT-PCR to evaluate the PLA2R1 mRNA expression and its promoter&rsquo, s methylation in breast cancer tissue in comparison to breast fibroadenomas. Our results describe, for the first time, the expression of PLA2R1 and the methylation of its promoter in human breast cancer tissues. A significant downregulation of PLA2R1, together with hypermethylation of the promoter was detected in breast cancers of different histological grades and molecular subtypes when compared to benign breast tissues. PLA2R1 promoter hypermethylation was associated with aggressive subtypes of breast cancer. In conclusion, PLA2R1 promoter hypermethylation is a potentially useful diagnostic and prognostic biomarker and could serve as a possible therapeutic target in breast cancer.

Despite advancement in breast cancer treatment, 30% of patients with early breast cancers experience relapse with distant metastasis. It is a challenge to identify patients at risk for relapse; therefore, the identification of markers and therapeutic targets for metastatic breast cancers is imperative. Here, we identified DP103 as a biomarker and metastasis-driving oncogene in human breast cancers and determined that DP103 elevates matrix metallopeptidase 9 (MMP9) levels, which are associated with metastasis and invasion through activation of NF-κB. In turn, NF-κB signaling positively activated DP103 expression. Furthermore, DP103 enhanced TGF-β–activated kinase-1 (TAK1) phosphorylation of NF-κB–activating IκB kinase 2 (IKK2), leading to increased NF-κB activity. Reduction of DP103 expression in invasive breast cancer cells reduced phosphorylation of IKK2, abrogated NF-κB–mediated MMP9 expression, and impeded metastasis in a murine xenograft model. In breast cancer patient tissues, elevated levels of DP103 correlated with enhanced MMP9, reduced overall survival, and reduced survival after relapse. Together, these data indicate that a positive DP103/NF-κB feedback loop promotes constitutive NF-κB activation in invasive breast cancers and activation of this pathway is linked to cancer progression and the acquisition of chemotherapy resistance. Furthermore, our results suggest that DP103 has potential as a therapeutic target for breast cancer treatment.

Metastatic breast cancer is still incurable so far; new specifically targeted and more effective therapies for triple-negative breast cancer (TNBC) are required in the clinic. In this study, our clinical data have established that basal and claudin-low subtypes of breast cancer (TNBC types) express significantly higher levels of Annexin A1 (ANXA1) with poor survival outcomes. Using human cancer cell lines that model the TNBC subtype, we observed a strong positive correlation between expression of ANXA1 and PPARγ. A similar correlation between these two markers was also established in our clinical breast cancer patients' specimens. To establish a link between these two markers in TNBC, we show de novo expression of ANXA1 is induced by activation of PPARγ both in vitro and in vivo and it has a predictive value in determining chemosensitivity to PPARγ ligands. Mechanistically, we show for the first time PPARγ-induced ANXA1 protein directly interacts with receptor interacting protein-1 (RIP1), promoting its deubiquitination and thereby activating the caspase-8–dependent death pathway. We further identified this underlying mechanism also involved a PPARγ-induced ANXA1-dependent autoubiquitination of cIAP1, the direct E3 ligase of RIP1, shifting cIAP1 toward proteosomal degradation. Collectively, our study provides first insight for the suitability of using drug-induced expression of ANXA1 as a new player in RIP1-induced death machinery in TNBCs, presenting itself both as an inclusion criterion for patient selection and surrogate marker for drug response in future PPARγ chemotherapy trials. Mol Cancer Ther; 16(11); 2528–42. ©2017 AACR.

Breast cancer is a heterogeneous disease comprising a diversity of tumor subtypes that manifest themselves in a wide variety of clinical, pathological, and molecular features. One important subset, luminal breast cancers, comprises two clinically distinct subtypes luminal A and B each of them endowed with its own genetic program of differentiation and proliferation. Luminal breast cancers were operationally defined as follows: Luminal A: ER+, PR+, HER2-, Ki-67

Background In 2014, breast cancer remains a major cause of mortality worldwide mostly due to tumor relapse and metastasis. There is currently a great interest in identifying cancer biomarkers and signalling pathways mechanistically related to breast cancer progression. Matrix metalloproteinase-9 (MMP-9) is a member of matrix degrading enzymes involved in cancer development, invasion and metastasis. Our objective was to investigate MMP-9 expression in normal human breast tissue and to compare it to that of breast cancer of various histological grades and molecular subtypes. We also sought to correlate MMP-9 expression with the incidence of metastasis, survival rates and relapse in breast cancer patients. Methods MMP-9 was first studied using in silico analysis on available DNA microarray and RNA sequencing data of human breast cancer tissues and human breast cancer cell lines. We next ascertained MMP-9 expression in both normal breast tissue and in human breast carcinoma tissue microarrays. Results Significant increase in MMP-9 expression was found in breast cancer cells where compared to normal breast tissue. A positive correlation could also be established between elevated levels of MMP-9 and breast cancer of high histological grade. Furthermore, our results indicate that not only MMP-9 is differentially expressed between each molecular subset but also, more importantly MMP-9 overexpression revealed itself as a startling feature of triple-negative and HER2-positive breast cancers. Lastly, the clinical relevance of MMP-9 overexpression is strongly supported by its significant association with a higher incidence of metastasis and relapse. Conclusions Differential expression of MMP-9 reflects the extent of cellular differentiation in breast cancer cells and is closely related to the most aggressive subtypes of breast cancer. Hence, MMP-9 is a promising prognostic biomarker of high-grade breast cancer. In our opinion, MMP-9 expression could help segregate subsets of aggressive breast cancer into clinically meaningful subtypes. Electronic supplementary material The online version of this article (doi:10.1186/1471-2407-14-609) contains supplementary material, which is available to authorized users.

Background: Breast cancer is a heterogeneous disease comprising a diversity of tumor subtypes. All of them differ from each other resulting in a wide array of clinical pictures, risks of recurrence and response to treatment. In recent years, tumor biomarkers have changed the way breast cancers are diagnosed and treated. In this paper we have sought to investigate the differential expression of ANXA1, a multifunctional calcium binding protein, among various molecular subtypes of breast cancers and in particular triple negative tumors. Methods: ANXA1 was first studied using in-silico analysis on available DNA microarray and RNA sequencing data of human breast tissues. Next we ascertained ANXA1 expression on cell lines and breast carcinoma tissue microarrays along with cognate normal breast tissue. Results: Whereas ANXA1 expression is normally restricted to the normal myoepithelial cell layer it becomes ectopically and aberrantly expressed in tumor cells of a significant minority of aggressive breast cancers. Specifically, we found that ANXA1 expression is severely deregulated in high-grade breast cancers that comprise clinically aggressive tumors such as triple-negative and, to some extent, HER2-positive breast cancers. Conclusion: Our results indicate that ANXA1 is a valuable breast cancer biomarker that can help to segregate and dissect out subsets of high histological grade breast cancers paving the way to a better understanding of breast cancer progression and metastasis.