Project description:PLAC1, cancer-testis antigen, is a crucial element in tumorigenesis and development programs for many cancers. Overexpression of PLAC1 promoted invasion and metastasis of breast cancer cells in vitro and in vivo. Co-immunoprecipitation and immunofluorescence cell staining assays be used revealed that PLAC1 physically interact with Furin to degrade Notch1 and generate NICD (Notch1 intracellar domain) and further inhibit Pten, which is also supported by the microarray analysis.
Project description:Small extracellular vesicles (sEVs) are emerging as critical mediators of intercellular communication in the tumor microenvironment. Here, we investigate the mechanisms by which sEVs derived from neutrophils treated with the cholesterol metabolite, 27-hydroxycholesterol (27HC), influence breast cancer progression. sEVs released from 27HC treated neutrophils enhance epithelial-mesenchymal transition (EMT) and stem-like properties in breast cancer cells, resulting in loss of adherence and increased migratory capacity. Decreased miRs within the sEVs resulted in activation of the WNT/ β-catenin signaling pathway in recipient cells and suggest that this may be a predominant pathway for stem-like phenotype and EMT. Our findings underscore a novel mechanism by which 27HC-modulated neutrophils contribute to breast cancer pathophysiology through EV-mediated intercellular communication, suggesting potential therapeutic targets in cancer treatment.
Project description:Expression of the tumor suppressor protein BRCA1 is frequently lost in breast cancer patients, and the loss of its expression is associated with disruption of various critical functions in cells and cancer development. In the present study, we demonstrated that microarray analysis of cells with tumor suppressor candidate 4 (TUSC4) knockdown indicated critical changes such as cell cycle, cell death pathways and a global impact to cancer development. More importantly, we observed a clear cluster pattern of TUSC4-knockdown gene profiles with established homologous recombination (HR) repair defect signature. Additionally, TUSC4 protein can physically interact with E3 ligase Herc2 and prevents BRCA1 degradation via ubiquitination pathway. Knockdown of TUSC4 expression enhanced BRCA1 polyubiquitination, leading to BRCA1 protein degradation and a marked reduction in HR repair efficiency. Notably, ectopic expression of TUSC4 effectively suppressed the proliferation, invasion, and colony formation of breast cancer cells in vitro and tumorigenesis in vivo. Furthermore, knockdown of TUSC4 expression transformed normal mammary epithelial cells and enhanced the sensitivity of U2OS cells to the treatment of poly(ADP-ribose) polymerase inhibitors. Therefore, TUSC4 may act as a bona fide tumor suppressor by regulating BRCA1 protein stability and function in breast cancer. Two groups of samples are included: 1.U2OS-shcontrol 2.U2OS-shTUSC4 knockdown. Gene expression profiles of U2OS-shTUSC4 cells were compared to that of parental U2OS-shcontrol cells.
Project description:Genome-wide association studies have identified over 70 common variants that are associated with breast cancer risk. Most of these variants map to non-protein-coding regions; several map to gene deserts, regions of several hundred kb lacking protein-coding genes. We hypothesized that gene deserts harbour long-range regulatory elements that can physically interact with target genes to influence their expression. To test this, we developed Capture Hi-C (CHi-C), which by incorporating a sequence capture step into a Hi-C protocol, allows high-resolution analysis of targeted regions of the genome. We used CHi-C to investigate long-range interactions at three breast cancer gene deserts mapping to 2q35, 8q24.21 and 9q31.2. We identified interaction peaks between putative regulatory elements ("bait fragments") within the captured regions and "targets" that included both protein-coding genes and long non-coding (lnc)RNAs, over distances of 6.6 kb to 2.6 Mb. Target protein-coding genes were IGFBP5, KLF4, NSMCE2 and MYC; target lncRNAs included DIRC3, PVT1 and CCDC26. For two gene deserts we were able to define a set of SNPs that were correlated with the published risk variant and that clustered within the bait end of an interaction peak. Preliminary functional analyses implicate one SNP (rs12613955; 2q35) as a potentially functional variant. Capture Hi-C was carried out in BT483, SUM44, and GM06990 cell lines to investigate breast cancer risk loci 2q35, 8q24.21 and 9q31.2.
Project description:SRC-1 (NCOA1) is a steroid receptor coactivator that has been associated with various aspects of the progression of breast cancer disease such as tamoxifen resistance, metastasis, cell proliferation and invasiveness. In a tamoxifen resistant breast cancer cell line (LY2), SRC-1 has been found to interact with the developmental transcription factor HoxC11. ChIP-sequencing of HoxC11 in LY2 cells shows where the transcription factor binds throughout the genome. LY2 cells were treated with either tamoxifen or vehicle and immunoprecipitated with anti-Hoxc11
Project description:Expression of the tumor suppressor protein BRCA1 is frequently lost in breast cancer patients, and the loss of its expression is associated with disruption of various critical functions in cells and cancer development. In the present study, we demonstrated that microarray analysis of cells with tumor suppressor candidate 4 (TUSC4) knockdown indicated critical changes such as cell cycle, cell death pathways and a global impact to cancer development. More importantly, we observed a clear cluster pattern of TUSC4-knockdown gene profiles with established homologous recombination (HR) repair defect signature. Additionally, TUSC4 protein can physically interact with E3 ligase Herc2 and prevents BRCA1 degradation via ubiquitination pathway. Knockdown of TUSC4 expression enhanced BRCA1 polyubiquitination, leading to BRCA1 protein degradation and a marked reduction in HR repair efficiency. Notably, ectopic expression of TUSC4 effectively suppressed the proliferation, invasion, and colony formation of breast cancer cells in vitro and tumorigenesis in vivo. Furthermore, knockdown of TUSC4 expression transformed normal mammary epithelial cells and enhanced the sensitivity of U2OS cells to the treatment of poly(ADP-ribose) polymerase inhibitors. Therefore, TUSC4 may act as a bona fide tumor suppressor by regulating BRCA1 protein stability and function in breast cancer.
Project description:Small extracellular vesicles (sEVs) are emerging as critical mediators of intercellular communication in the tumor microenvironment. Here, we investigate the mechanisms by which sEVs derived from neutrophils treated with the cholesterol metabolite, 27-hydroxycholesterol (27HC), influence breast cancer progression. sEVs released from 27HC treated neutrophils enhance epithelial-mesenchymal transition (EMT) and stem-like properties in breast cancer cells, resulting in loss of adherence and increased migratory capacity. Decreased miRs within the sEVs resulted in activation of the WNT/ β-catenin signaling pathway in recipient cells and suggest that this may be a predominant pathway for stem-like phenotype and EMT. Our findings underscore a novel mechanism by which 27HC-modulated neutrophils contribute to breast cancer pathophysiology through EV-mediated intercellular communication, suggesting potential therapeutic targets in cancer treatment.
Project description:In this study, we report that ZNF516 functions as a transcription repressor. We showed that ZNF516 is physically associated with the CtBP/LSD1/CoREST corepressor complex and transcriptionally represses the expression of a collection of genes including EGFR that are critically involved in cell proliferation and motility. We demonstrated that the ZNF516 inhibits the proliferation and invasive potential of breast cancer cells in vitro and suppresses breast cancer growth and metastasis in vivo. We explored the clinical significance of the ZNF516-CtBP/LSD1/CoREST-EGFR axis in breast carcinomas.
Project description:Metastatic behaviour varies significantly among breast cancers. Mechanisms explaining why the majority of breast cancer patients never develop metastatic outgrowth are largely lacking but could underlie the development of novel immunotherapeutic target molecules. Here we show interplay between non-metastatic primary breast cancer and innate immune response, acting together to control metastatic progression. The primary tumor systemically recruits IFNγ-producing immune effector monocytes to the lung. IFNγ upregulates Tmem173/STING in neutrophils and enhances their killing capacity. The immune effector monocytes and tumoricidal Tmem173/STINGhigh neutrophils target disseminated tumor cells in the lungs, preventing metastatic outgrowth. Importantly, our findings could underlie the development of immunotherapeutic target molecules that augment the function of immune effector monocytes and Tmem173high neutrophils.
Project description:Primary tumors have been shown to prepare distal organs for later colonization of metastatic cells by stimulating organ-specific infiltration of bone marrow-derived cells. Here we demonstrate that neutrophils accumulate in the lung prior to the arrival of metastatic cells in mouse models of breast cancer. Tumor-entrained neutrophils (TENs) inhibit metastatic seeding in the lungs by generating H2O2, and tumor-secreted CCL2 is a critical mediator of optimal anti-metastatic entrainment of G-CSF-stimulated neutrophils. TENs are present in the peripheral blood of breast cancer patients prior to surgical resection but not in healthy individuals. Thus, while tumor-secreted factors contribute to tumor progression at the primary site, they concomitantly induce a neutrophil-mediated inhibitory process at the metastatic site. This experiment was designed to compare the RNA expression profile in resting (control) neutrophils vs. that of TENs (neutrophils purified from tumor-bearing mice). In addition, we also compared the expression profiles of cultured neutrophils in vitro and treated with CCL2, CCL5 and GCSF.