Project description:While the basal-like subtype accounts for only a small subset of all breast cancer cases, it is associated with the worst prognosis. The majority of basal-like tumors are triple-negative (ER-, PR-, and HER2-negative), and thus lack molecular targets for therapy. To identify potential molecular markers and/or pathways that are critical to the basal-like tumor phenotype, we investigated the deregulation of microRNAs in primary breast tumors from an ethnically diverse cohort of patients. Forty-four microRNAs were identified as down-regulated in basal-like tumors compared to luminal-A tumors. MicroRNA-29c (miR-29c) was the most significantly down-regulated microRNA. In breast cancer cells in vitro, miR-29c was capable of regulating phenotypes associated with basal-like tumors such as cell invasion and drug sensitivity. Exogenous expression of miR-29c sensitizes UACC 3199 to doxorubicin-induced killing, while its inhibition leads to resistance to doxorubicin-induced killing. In addition, miR-29c decreases invasiveness of UACC-3199 cells, along with down-regulation of extracellular matrix (ECM) genes (LAMC1 and COL5A2) and ECM modifying enzyme LOXL2. In addition, miR-29c directly regulates B-MYB, an oncogene over expressed in basal-like tumors and co-expression of miR-29c and B-MYB abolishes UACC 3199 sensitivity to doxorubicin. Furthermore, our work demonstrates a regulatory role for the transcription factor GATA3 in miR-29c expression in breast cancer. Our findings support a role for miR-29c in basal-like breast tumorigenesis that is linked to drug resistance.
Project description:Triple-Negative Breast Cancer (TNBC) is a poorly targetable cancer subtype that exhibits a high metastatic potential. To develop new intervention strategies, it is crucial to understand the mechanisms governing migratory and invasive features of TNBC cells. Previously it was shown that high expression of the non-receptor tyrosine kinase FER is an independent prognostic factor that correlates with poor survival in high grade and basal breast cancer. Here, we show that FER controls proliferation and invasion of TNBC cells through the direct substrates MAPK1 and Dynactin 2 (DCTN2; Dynamitin). Our data demonstrate that FER regulates tumor cell proliferation through phosphorylation of MAPK1 on tyrosine 187, and recycling endosome function and subsequent invasion of breast cancer cells through tyrosine 6 residue (Y6) of DCTN2. We show that DCTN2-Y6 is essential for Dynein complex formation and the development of tubular recycling domains at the early endosome. By controlling this crucial step in endosomal recycling, FER drives and sustains adhesion and invasion of (triple negative) breast cancer cells. Our data provide clinical ramification by demonstrating that high grade and basal breast cancers expressing elevated FER levels are more susceptible to taxane-based chemotherapy interventions. In conclusion, our study links FER to kinase-dependent control of intracellular vesicular transport and tumor progression in breast cancer. Importantly, our results indicate that FER represents a predictive and functional biomarker in high grade basal breast cancers.
Project description:MicroRNAs (miRNAs) are small regulatory RNA molecules that modulate the activity of specific mRNA targets and play important roles in a wide range of physiologic and pathologic processes. We hypothesized that miRNAs might be involved in the progression of CKD. In our previous studies we found chronic renal damages developed progressively in rats with 5/6 nephrectomy. L-mimosine(L-Mim) intervention from wk 5 to wk 12 improved renal function and resulted in additional accumulation of HIF-1 α and -2 α at wk 12. In the current study we found miR-29c was up-regulated in the L-Mim treated group compared with the control using Agilent miRNA microarrays. Of the microRNAs and proteins that exhibited reciprocal changes in expression following the L-Mim treatment, miR-29c and tropomyosin 1α (TPM1), which is involved in stress fiber function, met the sequence criteria for microRNA-target interaction, were later confirmed by 3'-untranslated region reporter analysis. TGFβ1 treatment (3 ng/ml, 24 hours) decreased miR-29c expression and up-regulated protein expression of TPM1 in human renal epithelial cells. Overexpression of miR-29c significantly attenuated TGF-β1 induced increase in TPM1 in vitro. Moreover, intrarenal expression of miR-29c was decreased in IgAN patients with moderate to severe tubulointerstital fibrosis (TIF), compared with IgAN patients without TIF, and intrarenal protein expression of TMP1 was significantly increased in IgAN patients with TIF. The results suggest that intrarenal expression of miR-29c was down-regulated while its predicted target, TPM1 was up-regulated in the progression of CKD. Short term stabilizing of HIF up-regulates miR-29c and attenuates CKD in the remnant kidney model.
Project description:Analysis of miRNA expression in grade 3 luminal, sporadic and BRCA1 associated basal-like breast cancers 44 primary grade III breast cancer (11 BRCA1 basal, 16 sporadic basal, 17 luminal) and 13 normal breast FFPE (formalin fixed, paraffin embedded) specimens, plus 7 controls and 5 cell lines were analysed. The aim of the study was to derive grade-specific miRNA signatures for sporadic and BRCA1 basal-like breast cancers, and to ascertain an immunohistochemical profile regulated by BRCA1 specific miRNAs for potential diagnostic uses.
Project description:Purpose: Breast cancer is a genetically heterogenous disease with subtypes differing in prognosis and chemosensitivity. The basal-like breast cancer (BLBC) molecular subtype is associated with poorer outcomes, but is more responsive to taxane-based chemotherapy. We evaluated the role of kinesins, motor proteins interacting with microtubules, in influencing taxane resistance. Experimental Design: Kinesin (KIF) expression was studied in one local dataset comprising all taxane resistant breast cancers in relation to taxane resistance. Data in the NCI-60 cell line dataset (GSE5846) nd the MDACC dataset (GSE20194) is separately detailed. Results: In the local dataset, the kinesin KIF26B is overexpressed in taxane-resistant residual breast cancers post-chemotherapy. Conclusions: We show that kinesin overexpression correlates with taxane resistance in BLBC cell lines and tissue. Our results suggest a potential approach to overcoming taxane resistance through concurrent or sequential use of kinesin inhibitors, highlighting the ATP-binding domain as a drug development target. Kinesin (KIF) expression was studied in one local dataset comprising all taxane resistant breast cancers in relation to taxane resistance. Data in the NCI-60 cell line dataset (GSE5846) and the MDACC dataset (GSE20194) is separately detailed.
Project description:MicroRNAs (miRNAs) are small regulatory RNA molecules that modulate the activity of specific mRNA targets and play important roles in a wide range of physiologic and pathologic processes. We hypothesized that miRNAs might be involved in the progression of CKD. In our previous studies we found chronic renal damages developed progressively in rats with 5/6 nephrectomy. L-mimosine(L-Mim) intervention from wk 5 to wk 12 improved renal function and resulted in additional accumulation of HIF-1 M-NM-1 and -2 M-NM-1 at wk 12. In the current study we found miR-29c was up-regulated in the L-Mim treated group compared with the control using Agilent miRNA microarrays. Of the microRNAs and proteins that exhibited reciprocal changes in expression following the L-Mim treatment, miR-29c and tropomyosin 1M-NM-1 (TPM1), which is involved in stress fiber function, met the sequence criteria for microRNA-target interaction, were later confirmed by 3'-untranslated region reporter analysis. TGFM-NM-21 treatment (3 ng/ml, 24 hours) decreased miR-29c expression and up-regulated protein expression of TPM1 in human renal epithelial cells. Overexpression of miR-29c significantly attenuated TGF-M-NM-21 induced increase in TPM1 in vitro. Moreover, intrarenal expression of miR-29c was decreased in IgAN patients with moderate to severe tubulointerstital fibrosis (TIF), compared with IgAN patients without TIF, and intrarenal protein expression of TMP1 was significantly increased in IgAN patients with TIF. The results suggest that intrarenal expression of miR-29c was down-regulated while its predicted target, TPM1 was up-regulated in the progression of CKD. Short term stabilizing of HIF up-regulates miR-29c and attenuates CKD in the remnant kidney model. Four weeks after 5/6 nephrectomy, rats were treated with intraperitoneal injections of vehicle or L-mimosine (L-Mim, Calbiochem), a prolyl 4-hydroxylase inhibitor (PHD), at a dosage of 50 mg/kg every other day. At the end of wk 12 after 5/6 nephrectomy, all rats (n=4, for each group) were sacrificed and blood samples were collected via cardiac puncture. Renal tissue were harvested, one piece of which was fixed in neutral formalin and then embedded in paraffin. The remaining kidney tissue was dissected in ice-cold PBS to, remove medulla, and then snap-frozen in liquid nitrogen before transferring to storage at -80M-BM-0C until further analysis.
Project description:Epithelial-to-mesenchymal transition (EMT) is a dynamic process that relies on cellular plasticity; an EMT/MET axis is critical for metastatic colonization of carcinomas. Unlike epithelial programming, regulation of mesenchymal programming is not well understood in EMT. Here we describe the first microRNA that enhances exclusively mesenchymal programming. We demonstrate that microRNA-424 is up-regulated early during a TWIST1/SNAI1-induced EMT, and that it causes cells to express mesenchymal genes without affecting epithelial genes, resulting in a mixed/intermediate EMT. Further, microRNA-424 increases motility, decreases adhesion and induces a growth arrest, changes associated with a complete EMT. Patient microRNA-424 levels positively associate with TWIST1/2 and EMT-like gene signatures and is increased in primary tumors versus matched normal breast. However, microRNA-424 is down-regulated in metastases versus matched primary tumors. Correspondingly, microRNA-424 decreases tumor initiation and is post-transcriptionally down-regulated in macrometastases in mice. RNA-seq identified microRNA-424 regulates numerous genes associated with EMT and breast cancer stemness including the novel miR-424 target, TGFBR3, which regulates mesenchymal phenotypes without influencing miR-424 effects on tumor-initiating phenotypes; instead, we show that ERK signaling is critical for such tumor-initiating effects of miR-424. These findings suggest microRNA-424 plays distinct roles downstream of EMT-inducing factors, facilitating earlier stages, but repressing later stages, of metastasis. Examination of mRNA levels in MCF12A human breast cell lines that stably over-expressed miR-424 or an empty vector (EV) control. Each group has three replicates.
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:Epithelial-to-mesenchymal transition (EMT) is a dynamic process that relies on cellular plasticity; an EMT/MET axis is critical for metastatic colonization of carcinomas. Unlike epithelial programming, regulation of mesenchymal programming is not well understood in EMT. Here we describe the first microRNA that enhances exclusively mesenchymal programming. We demonstrate that microRNA-424 is up-regulated early during a TWIST1/SNAI1-induced EMT, and that it causes cells to express mesenchymal genes without affecting epithelial genes, resulting in a mixed/intermediate EMT. Further, microRNA-424 increases motility, decreases adhesion and induces a growth arrest, changes associated with a complete EMT. Patient microRNA-424 levels positively associate with TWIST1/2 and EMT-like gene signatures and is increased in primary tumors versus matched normal breast. However, microRNA-424 is down-regulated in metastases versus matched primary tumors. Correspondingly, microRNA-424 decreases tumor initiation and is post-transcriptionally down-regulated in macrometastases in mice. RNA-seq identified microRNA-424 regulates numerous genes associated with EMT and breast cancer stemness including the novel miR-424 target, TGFBR3, which regulates mesenchymal phenotypes without influencing miR-424 effects on tumor-initiating phenotypes; instead, we show that ERK signaling is critical for such tumor-initiating effects of miR-424. These findings suggest microRNA-424 plays distinct roles downstream of EMT-inducing factors, facilitating earlier stages, but repressing later stages, of metastasis.