Project description:miR-16 is a potent tumor suppressor in ErbB-2 positive breast cancer. The primary objetive of this study was to identify previously uncharacterized putative mRNA targets of miR-16 in ErbB-2 postitive breast cancer cells. To achieve our objective we studied the effects of exogenously expressed miR-16 on the gene expression profile of primary cultures of ErbB-2 positive murine breast cancer tumors. The C4HD tumor line displays high levels of estrogen receptor and progesterone receptor, overexpresses ErbB-2 and ErbB-3, exhibits low ErbB-4 levels, and lacks EGF-R expression.
Project description:Gene expression analysis on MEL-18-knockdown BT474 cells. MEL-18, a polycomb group protein and a member of the polycomb repressive complex 1 (PRC1), have suggested as a tumor suppressor in several cancer, including breast cancer. The results provides that the depletion of MEL-18 in HER2-positive breast cancer causes the activation of ErbB signaling pathway. We proposed that MEL-18 is a novel prognostic and therapeutic marker for HER2-positive breast cancer.
Project description:DCD is a gene amplified and overexpressed in a subset of breast tumors acting as a growth and survival factor. Patients with DCD-positive breast cancer have worse prognostic features. To investigate the role of DCD in breast tumorigenesis, we analyzed the consequences of its downregulation in human breast cancer cell lines using three specific shRNA lentivirus vectors. Genes up- and down-regulated by DCD were identified using Affymetrix microarray and analyzed by MetaCore Platform. We found that loss of DCD expression led to reduced cell proliferation, resistance to apoptosis, and suppressed tumorigenesis in immunodeficient mice. Network analysis of gene expression data revealed perturbed ERBB signaling following DCD shRNA expression including changes in the expression of ERBB receptors and their ligands. These findings imply that DCD promotes breast tumorigenesis via modulating the activity of the ERBB signaling pathways. As ERBB signaling is also important for neural survival, HER2+ breast tumors may highjack DCD’s neural survival-promoting functions to promote tumorigenesis.
Project description:Breast Cancer is the cancer with most incidence and mortality in women. microRNAs are emerging as novel prognosis/diagnostic tools. Our aim was to identify a serum microRNA signature useful to predict cancer development. We focused on studying the expression levels of 30 microRNAs in the serum of 96 breast cancer patients versus 92 control individuals. Bioinformatic studies provide a microRNA signature, designated as a predictor, based upon the expression levels of 5 microRNAs. Then, we tested the predictor in a group of 60 randomly chosen women. Lastly, a proteomic study unveiled the over-expression and down-regulation of proteins differently expressed in the serum of breast cancer patients versus that of control individuals. Twenty-six microRNAs differentiate cancer tissue from healthy tissue and 16 microRNAs differentiate the serum of cancer patients from that of the control group. The tissue expression of miR-99a-5p, mir-497-5p, miR-362, and miR-1274, and the serum levels of miR-141 correlated with patient survival. Moreover, the predictor consisting of mir-125b-5p, miR-29c-3p, mir-16-5p, miR-1260, and miR-451a was able to differentiate breast cancer patients from controls. The predictor was validated in 20 new cases of breast cancer patients and tested in 60 volunteer women, assigning 11 out of 60 women to the cancer group. An association of low levels of mir-16-5p with a high content of CD44 protein in serum was found. Circulating microRNAs in serum can represent biomarkers for cancer prediction. Their clinical relevance and use of the predictor here described might be of potential importance for breast cancer prediction.
Project description:MicroRNA profiles of 110 primary breast cancer tumors of systematically untreated, lymph node negative and ER positive patients. Half of the patients developed metastasis while 55 patients remained metastasis-free. The miRCURY LNA microRNA array ready-to-spot probe-set was purchased from Exiqon. The set contains capture-probes for 1212 human, 1040 mouse and 679 rat miRNAs based on the miRBase version 16. Probes were spotted in triplets on CodeLink HD (SurModics) activated glass slides and post-processed according to the CodeLink protocol. SUBMITTER_CITATION: Ines Block, Mark Burton, Kristina P. Sørensen, Lars Andersen, Martin J. Larsen, Martin Bak, Søren Cold, Mads Thomassen, Qihua Tan, Torben A. Kruse. Association of miR-548c-5p, miR-7-5p, miR-210-3p, miR-128-3p with recurrence in systemically untreated breast cancer. Oncotarget 2018 Jan; 9:9030-9042. https://doi.org/10.18632/oncotarget.24088
Project description:In this study, we probed the importance of OGT activity for the survival of Tamoxifen-sensitive (TamS) and Tamoxifen-resistant (TamR) breast cancer cells. Tamoxifen is an antagonist of estrogen receptor (ERα), a transcription factor expressed in over half of all breast cancers, and the defining characteristic of the ERα-positive disease. ERα-positive breast cancers are successfully treated with Tamoxifen; however, a significant number of patients develops Tamoxifen-resistant disease. We show here that in vitro development of Tamoxifen-resistance results in acquired sensitivity to OGT small molecule inhibitor OSMI-1. Global transcriptome profiling revealed that TamS cells adapt to OSMI-1 treatment by undergoing significant chromatin compaction. In the TamR cells, however, OGT inhibition induces ERRFI1 tumor-suppressor gene expression. ERRFI1 is an endogenous inhibitor of ERBB-signaling, while activation of the ERBB-signaling is one of the best understood mechanism for Tamoxifen-resistance. We show that ERRFI1 is selectively downregulated in ERα-positive breast cancers and breast cancers driven by ERBB2, and provide data to support that this occurs through promoter methylation. Finally, we show that increased ERRFI1 expression is associated with extended survival in patients with ERα-positive tumors (p=9.2e-8). In summary, we show that Tamoxifen-resistance is associated with acquired sensitivity to OSMI-1, and propose that this is explained in part through an epigenetic activation of the tumor-suppressor ERRFI1 in response to OSMI-1 treatment.
Project description:Childhood exposure to carcinogens renders a higher risk of breast cancer. The molecular mechanisms underlying cancer development after such exposure are not, however, well understood. Here we examined how the mechanism of cancer development relates to the age at exposure to ionizing radiation (IR) or the carcinogen 1-methyl-1-nitrosourea (MNU). Pre- and postpubertal (3- and 7-week-old, respectively) female Sprague-Dawley rats were whole-body gamma-irradiated (2 Gy), injected intraperitoneally with MNU (20 mg/kg) or left untreated and were autopsied at 50 weeks of age. Mammary carcinomas were examined for estrogen receptor (ER) alpha, progesterone receptor (PR) and ErbB ligand expression and for expression microarrays. Early histological changes of the ovaries were also evaluated. The incidence of mammary cancer was higher after postpubertal, rather than prepubertal, IR exposure; the inverse was true for MNU. Most cancers were positive for both ER alpha and PR except for the prepubertal IR group. Interestingly, cancers of the prepubertal IR group expressed a different set of ErbB ligands from those of the other groups and did not overexpress Areg, which encodes an estrogen-regulated ErbB ligand, or other developmentally related genes including those for hormonally regulated mammary gland development. Prepubertal IR exposure resulted in ovarian dysfunction as revealed by a reduced follicular pool. Evidence thus suggests that mammary carcinogenesis induced by prepubertal IR exposure is independent of ovarian hormones but requires certain ErbB ligands; induction by postpubertal exposure depends on ovarian hormones and different ErbB ligands. In contrast, MNU-induced carcinogenesis was less influenced by the age at exposure.