Growing evidence of transcriptional and metabolomic differentiation induced many studies which analyze such differentiation in context of outcome of disease progression, treatment or influence of many different factors affecting cellular and tissue metabolism. Particularly, cancer researchers are looking for new biomarkers that can serve as a diagnostic/prognostic factor and its further corresponding relationship regarding clinical effects. As a result of the increasing interest in use of dichotomization of continuous variables involving clinical or epidemiological data (gene expression, biomarkers, biochemical parameters, etc.) there is a large demand for cutoff point determination tools with simultaneous lack of software offering stratification of patients based on continuous and binary variables. Therefore, we developed "Evaluate Cutpoints" application offering wide set of statistical and graphical methods for cutpoint optimization enabling stratification of population into two or three groups. Application is based on R language including algorithms of packages such as survival, survMisc, OptimalCutpoints, maxstat, Rolr, ggplot2, GGally and plotly offering Kaplan-Meier plots and ROC curves with cutoff point determination. All capabilities of Evaluate Cutpoints were illustrated with example analysis of estrogen, progesterone and human epidermal growth factor 2 receptors in breast cancer cohort. Through ROC curve the cutoff points were established for expression of ESR1, PGR and ERBB2 in correlation with their immunohistochemical status (cutoff: 1301.253, 243.35, 11,434.438, respectively; sensitivity: 94%, 85%, 64%, respectively; specificity: 93%, 86%, 91%, respectively). Through disease-free survival analysis we divided patients into two and three groups regarding expression of ESR1, PGR and ERBB2. Example algorithm cutp showed that lowered expression of ESR1 and ERBB2 was more favorable (HR = 2.07, p = 0.0412; HR = 2.79, p = 0.0777, respectively), whereas heightened PGR expression was correlated with better prognosis (HR = 0.192, p = 0.0115). This work presents application Evaluate Cutpoints that is freely available to download at http://wnbikp.umed.lodz.pl/Evaluate-Cutpoints/. Currently, many softwares are used to split continuous variables such as Cutoff Finder and X-Tile, which offer distinct algorithms. Unlike them, Evaluate Cutpoints allows not only dichotomization of populations into groups according to continuous variables and binary variables, but also stratification into three groups as well as manual selection of cutoff point thus preventing potential loss of information.

Protein domains mediate protein—protein interactions through binding to short peptide motifs in their corresponding ligands. These peptide recognition modules are critical for the assembly of multiprotein complexes. We have arrayed glutathione S-transferase (GST) fusion proteins, with a focus on protein interaction domains, on to nitrocellulose-coated glass slides to generate a protein-domain chip. Arrayed protein-interacting modules included WW (a domain with two conserved tryptophans), SH3 (Src homology 3), SH2, 14.3.3, FHA (forkhead-associated), PDZ (a domain originally identified in PSD-95, DLG and ZO-1 proteins), PH (pleckstrin homology) and FF (a domain with two conserved phenylalanines) domains. Here we demonstrate, using peptides, that the arrayed domains retain their binding integrity. Furthermore, we show that the protein-domain chip can ‘fish’ proteins out of a total cell lysate; these domain-bound proteins can then be detected on the chip with a specific antibody, thus producing an interaction map for a cellular protein of interest. Using this approach we have confirmed the domain-binding profile of the signalling molecule Sam68 (Src-associated during mitosis 68), and have identified a new binding profile for the core small nuclear ribonucleoprotein SmB′. This protein-domain chip not only identifies potential binding partners for proteins, but also promises to recognize qualitative differences in protein ligands (caused by post-translational modification), thus getting at the heart of signal transduction pathways.

WWOX, the gene that maps to common chromosomal fragile site FRA16D, is frequently affected by aberrations in multiple types of cancers. WWOX encodes a 46 kDa protein that contains two WW domains and a short-chain oxidoreductase (SDR) domain. We recently demonstrated that ectopic expression of WWOX inhibits xenograft tumor growth of tumorigenic breast cancer cells. Little is known of the biochemical function(s) of WWOX. The SDR domain is predicted to be involved in sex-steroid metabolism and the WW domains are likely involved in protein–protein interactions. In this report, we identify the specific proline-rich ligand for WWOX as PPXY and show that the amino-terminal WW domain is responsible for this interaction. Using the WWOX WW domains as a probe, we screened high-density protein arrays and identified five candidate-binding partners. The binding to one of these candidates, small membrane protein of the lysosome/late endosome (SIMPLE), was further analysed, and we observed that a specific PPSY motif in the SIMPLE amino-acid sequence was required to interact with the amino-terminal WW domain of WWOX. In addition, immunofluorescence staining demonstrated that endogenous WWOX and SIMPLE co-localize to perinuclear compartments of MCF-7 human breast cancer cells. These studies demonstrate that WWOX contains a Group I WW domain that binds known cellular proteins containing the specific ligand PPXY. Identification and characterization of WWOX interacting proteins will lead to an understanding of the biological functions of WWOX in normal and tumor cells.

Aberrations in DNA methylation patterns have been reported to be involved in driving changes in the expression of numerous genes during carcinogenesis and have become promising targets for chemopreventive action of natural compounds. In the present study, we investigated the effects of all-transretinoic acid (ATRA), vitamin D₃and resveratrol alone and in combination with adenosine analogues, 2-chloro-2′-deoxyadenosine (2CdA) and 9-β-d-arabinosyl-2-fluoroadenine (F-ara-A), on the methylation and expression of phosphatase and tensin homologue (PTEN) tumour suppressor gene in MCF-7 and MDA-MB-231 breast cancer cells. The present results showed that in non-invasive MCF-7 cells, ATRA, vitamin D₃and resveratrol possess high efficacy in the reduction ofPTENpromoter methylation. It was associated withPTENinduction as well as DNA methyltransferase down-regulation andp21up-regulation after treatments with vitamin D₃and resveratrol, suggesting a complex regulation of the DNA methylation machinery. Vitamin D₃and resveratrol improved the inhibitory effects of 2CdA and F-ara-A onPTENmethylation in MCF-7 cells; however, only the combined action of vitamin D₃and 2CdA boosted the induction ofPTENexpression, suggesting a cooperation of these compounds in additional processes driving changes inPTENexpression. In contrast, in highly invasive MDA-MB-231 cells, only vitamin D₃reducedPTENmethylation and induced its expression without notable effects in combined treatments. The present results suggest that natural compounds can find application in epigenetic anticancer therapy aimed at inhibition of promoter methylation of tumour suppressor genes and induction of their expression at early stages of carcinogenesis.