KLK6-regulated miRNA networks activate oncogenic pathways in breast cancer subtypes.

KLK6 is expressed in normal mammary tissues and is aberrantly regulated in breast cancer. At physiological levels of expression, i.e. those found in normal mammary tissues, KLK6 acts as a tumor suppressor in human breast cancer. However, aberrant overexpression of KLK6 (i.e. 50-100-fold higher than normal), a characteristic of a subset of human breast cancers is associated with increased tumorigenicity (Pampalakis et al. Cancer Res 69:3779-3787, 2009). Here, we stably transfected KLK6-non-expressing MDA-MB-231 breast cancer cells with the full-length KLK6 cDNA to overexpress KLK6 at levels comparable to those observed in patients, and investigated potential oncogenic miRNA networks regulated by these abnormally high KLK6 expression levels and increased activity of this serine protease. A number of miRNAs that are upregulated (e.g. miR-146a) or downregulated (e.g. miR-34a) via KLK6-induced alterations in the miRNA biogenesis machinery were identified. Integrated experimental and bioinformatics analyses identified convergent miRNA networks targeting the cell cycle, MYC, MAPK, and other signaling pathways. In large clinical datasets, significant correlations between KLK6 and downstream MAPK and MYC targets at both the RNA and protein levels was confirmed, as well as negative correlation with GATA3. It was also demonstrated that KLK6 overexpression and likely its proteolytic activity is associated with alterations in downstream miRNAs and their targets, and these differ with the molecular subtypes of breast cancer. The data partly explains the different characteristics of breast cancer subtypes. Importantly, we introduce a combined KLK6-CDKN1B+MYC+CDKN1C score for prediction of long-term patient survival outcomes, with higher scores indicating poor survival.

MicroRNA-194 is a Marker for Good Prognosis in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is the most prevalent adult kidney cancer. Prognostic markers are needed to guide patient management toward aggressive versus more conservative approaches, especially for small tumors ≤4 cm. miR-194 was reported to be downregulated in several cancers and is involved in epithelial to mesenchymal transition. We evaluated miR-194 as a prognostic marker in ccRCC. In a cohort of 234 patients with primary ccRCC, we correlated miR-194 expression level with multiple clinicopathological features including disease-free and overall survival, tumor size, clinical stage, and histological grade. Our results shows a stepwise decrease in miR-194 expression from normal kidney to primary ccRCC (P = 0.0032) and a subsequent decrease from primary to metastatic lesions. Additionally, patients with higher miR-194 expression has significantly longer disease-free survival (P = 0.041) and overall survival (P = 0.031) compared to those with lower expression. In multivariate analysis, miR-194-positive tumors retain significance in disease-free survival and overall survival, suggesting miR-194 is an independent marker for good prognosis in ccRCC. Moreover, miR-194 is a marker for good prognosis for patients with small renal masses (P = 0.014). These findings were validated on an independent data set from The Cancer Genome Atlas. We also compared miR-194 expression between RCC subtypes. ccRCC had the highest levels, whereas chromophobe RCC and oncocytoma had comparable lower levels. Target prediction coupled with pathway analysis show that miR-194 is predicted to target key molecules and pathways involved in RCC progression. miR-194 represents a prognostic biomarker in ccRCC.

Primary cutaneous T-cell lymphomas: a review.

Primary cutaneous T-cell lymphomas (CTCLs) represent a number of extranodal lymphomas arising from a malignant population of lymphocytes in the skin, with the most common type being mycosis fungoides (MF) representing half of all primary CTCLs. Despite advances in immunohistochemistry and molecular methodology, significant diagnostic challenges remain due to phenotypic overlap of primary CTCLs with several inflammatory dermatoses, secondary lymphomas, among other conditions. Clinical features such as presentation and morphology, staging, histology, immunophenotype and molecular features must be considered in detail before a diagnosis is made in order to minimise false-positive, false-negative and indeterminate diagnoses. Herein, we review primary CTCLs, including epidemiological data, a brief summary of clinical presentations, immunophenotype, molecular signatures and differential diagnoses.

Kallikrein-related peptidase 5 induces miRNA-mediated anti-oncogenic pathways in breast cancer.

Kallikrein-related peptidase 5 (KLK5) displays aberrant expression in cancer. Recently, we showed KLK5 reconstitution in breast cancer cell lines suppresses malignancy. Present study aims to investigate the functional KLK5 mediated miRNA network on breast cancer progression, molecular subtype and survival. 28 miRNAs were up-regulated and 62 miRNAs were down-regulated upon KLK5 expression. Extracellular matrix (ECM) molecules and cell-adhesion pathways were the most significant KLK5-induced miRNA-mediated regulatory targets. Validation from The Cancer Genome Atlas (TCGA) database indicated KLK5 was specifically down-regulated in luminal B and basal-like breast cancer subtypes. There was a correlation between KLK5, miRNAs and their downstream ECM gene targets. Long-term patient survival correlated with dysregulation of KLK5 and interacting ECM target genes. It suggests biological differences between breast cancer molecular subtypes, patient survival, and their propensity for invasion and metastasis can be explained in part by altered miRNA networks induced by KLK5 dysregulation. We provide the first evidence that KLK5 can affect miRNA networks, which regulate MMPs and other novel ECM targets and a new compelling hypothesis of interplay between serine proteases and miRNAs. We developed a combined KLK5-(ITGB1+COL12A1) predictive score for recurrence-free survival that could be exploited in clinical applications.

Hepatic PTP-1B expression regulates the assembly and secretion of apolipoprotein B-containing lipoproteins: evidence from protein tyrosine phosphatase-1B overexpression, knockout, and RNAi studies.

Protein tyrosine phosphatase-1B (PTP-1B) plays an important role in regulation of insulin signal transduction, and modulation of PTP-1B expression seems to have a profound effect on insulin sensitivity and diet-induced weight gain. The molecular link between PTP-1B expression and metabolic dyslipidemia, a major complication of insulin resistance, was investigated in the present study using PTP-1B knockout mice as well as overexpression and suppression of PTP-1B. Chronic fructose feeding resulted in a significant increase in plasma VLDL in wild-type mice but not in PTP-1B knockout mice. Lipoprotein profile analysis of plasma from PTP-1B knockout mice revealed a significant reduction in apolipoprotein B (apoB100) lipoproteins, associated with reduced hepatic apoB100 secretion from isolated primary hepatocytes. In addition, treatment of cultured hepatoma cells with PTP-1B siRNA reduced PTP-1B mass by an average of 41% and was associated with a 53% decrease in secretion of metabolically labeled apoB100. Conversely, adenoviral-mediated overexpression of PTP-1B in HepG2 cells downregulated the phosphorylation of insulin receptor and insulin receptor substrate-1 and caused increases in cellular and secreted apoB100 as a result of increased intracellular apoB100 stability. Collectively, these findings suggest that PTP-1B expression level is a key determinant of hepatic lipoprotein secretion, and its overexpression in the liver can be sufficient to induce VLDL overproduction and the transition to a metabolic dyslipidemic state.