Targeted therapies have yet to have significant impact on the survival of patients with bladder cancer. In this study, we focused on the urea cycle enzyme argininosuccinate synthetase 1 (ASS1) as a therapeutic target in bladder cancer, based on our discovery of the prognostic and functional import of ASS1 in this setting. ASS1 expression status in bladder tumors from 183 Caucasian and 295 Asian patients was analyzed, along with its hypothesized prognostic impact and association with clinicopathologic features, including tumor size and invasion. Furthermore, the genetics, biology, and therapeutic implications of ASS1 loss were investigated in urothelial cancer cells. We detected ASS1 negativity in 40% of bladder cancers, in which multivariate analysis indicated worse disease-specific and metastasis-free survival. ASS1 loss secondary to epigenetic silencing was accompanied by increased tumor cell proliferation and invasion, consistent with a tumor-suppressor role for ASS1. In developing a treatment approach, we identified a novel targeted antimetabolite strategy to exploit arginine deprivation with pegylated arginine deiminase (ADI-PEG20) as a therapeutic. ADI-PEG20 was synthetically lethal in ASS1-methylated bladder cells and its exposure was associated with a marked reduction in intracellular levels of thymidine, due to suppression of both uptake and de novo synthesis. We found that thymidine uptake correlated with thymidine kinase-1 protein levels and that thymidine levels were imageable with [ 18 F]-fluoro-L-thymidine (FLT)-positron emission tomography (PET). In contrast, inhibition of de novo synthesis was linked to decreased expression of thymidylate synthase and dihydrofolate reductase. Notably, inhibition of de novo synthesis was associated with potentiation of ADI-PEG20 activity by the antifolate drug pemetrexed. Taken together, our findings argue that arginine deprivation combined with antifolates warrants clinical investigation in ASS1-negative urothelial and related cancers, using FLT-PET as an early surrogate marker of response. Cancer Res; 74(3); 896-907. Ó2013 AACR.

Thymidylate synthase (TYMS) is the crucial enzymatic precursor for DNA biosynthesis and, therefore, the critical target for numerous types of chemotherapy, including the most frequently applied agent in colon cancer treatment 5-fluorouracil (5-FU). TYMS also seems to be associated with cancer metastasis and acquiring mesenchymal character by tumor cells during epithelial–mesenchymal transition (EMT). Based on that knowledge, we decided to investigate the role of TYMS in the modulation of invasive ability in colon cancer cells, where its effect on cancer metastasis has not been studied in detail before. We employed colon cancer cells isolated from different stages of tumor development, cells undergoing EMT, and TYMS overexpressing cells. The elongation ratio, cell migration, invasion assay, and MMP-7 secretion were applied to analyze the cell behavior. Important epithelial and mesenchymal markers characteristic of EMT were examined at the protein level by Western blot assay. Overall, our study showed a correlation between TYMS level and invasion ability in colon cancer cells and, above all, a crucial role of TYMS in the EMT regulation. We postulate that chemotherapeutics that decrease or inhibit TYMS expression could increase the effectiveness of the therapy in patients with colon cancer, especially in the metastatic stage.

Gestational diabetes mellitus (GDM) is defined as a glucose intolerance of varying severity with onset or first recognition during pregnancy. The prevalence of GDM is growing rapidly worldwide, resulting in numerous and serious complications for both mother and foetus. Two major metabolic disorders, insulin resistance and β cells dysfunction, are currently linked to the pathogenesis of GDM, although the cellular mechanisms involved in the development of GDM are not yet completely understood. Increasing evidence from clinical and experimental studies indicates that adipose tissue dysfunction, characterised by abnormal production of adipokines, is an essential factor linked to insulin resistance and GDM. To date, several adipose tissue-derived hormones have been identified, including leptin, adiponectin, resistin, visfatin, apelin, retinol-binding protein 4 (RBP-4), vaspin, and omentin. The relationship of leptin and adiponectin to insulin resistance in GDM is relatively well documented, but the molecular mechanisms by which these hormones affect insulin resistance are not yet fully known. The other aforementioned adipokines appear to be also important players in the pathophysiology of GDM, although their precise function in this complex process remains to be established. The aim of this article is to review the literature concerning the relationship between the above-mentioned adipokines and GDM, and to clarify their role in the pathophysiology of GDM. Key words: adipokines; adiponectin; gestational diabetes mellitus (GDM); leptin; omentin; RBP-4; resistin; vaspin; visfatin StreszczenieCukrzyca ciążowa (GDM) jest definiowana jako nietolerancja glukozy, która po raz pierwszy wystąpiła lub została wykryta w czasie ciąży. Zachorowalność na GDM szybko wzrasta na świecie, prowadząc do licznych i poważnych powikłań zarówno u matki, jak i płodu. Dwa główne zaburzenia metaboliczne, czyli oporność na insulinę i dysfunkcja komórek b, biorą udział w patogenezie GDM, jednak komórkowe mechanizmy prowadzące do jej rozwoju nie są jeszcze do końca poznane. Wyniki badań klinicznych i eksperymentalnych wskazują, że dysfunkcja tkanki tłuszczowej, charakteryzująca się nieprawidłową produkcją adipokin, jest istotnym czynnikiem związanym z GDM. Do tej pory zidentyfikowano kilka hormonów wytwarzanych przez tkankę tłuszczową, w tym leptynę, adiponektynę, rezystynę, wisfatynę, apelinę, białko wiążące retinol 4 (RBP-4), waspinę i omentynę. Spośród nich stosunkowo dobrze udokumentowany jest związek leptyny i adiponektyny z insulinoopornością w GDM, ale molekularne mechanizmy działania obydwu hormonów w tym procesie nie są jeszcze całkowicie wyjaśnione. Pozostałe wyżej wymienione adipokiny wydają się być również istotnymi czynnikami w patofizjologii GDM, chociaż ich dokładna funkcja w tym kompleksowym procesie pozostaje niejasna. Celem niniejszego artykułu był przegląd istniejącej literatury dotyczącej związku między wyżej wymienionymi adipokinami i GDM oraz wyjaśnienie ich roli w patofizjologii GDM. (Endokrynol Pol 2014; 65 (2): 1...

Extracts from the defatted evening primrose (Oenothera paradoxa Hudziok) seeds are the source of a range of stable polyphenolic compounds, including ellagic acid, gallic acid, and catechin. Our studies evaluate, for the first time, the influence of evening primrose isopropanol extract (EPE) on malignant pleural mesothelioma (MPM) cells. MPM is rarely diagnosed, its high aggressiveness and frequently noted chemoresistance limit its treatment schemes and it is characterized by low prognostic features. Here, we demonstrate that EPE inhibited MPM growth in a dose-dependent manner in cells with increased invasion properties. Moreover, EPE treatment resulted in cell cycle arrest in the G2/M phase and increased apoptosis in invasive MPM cell lines. Additionally, EPE strongly limited invasion and MMP-7 secretion in MPM cancer cells. Our original data provide evidence about the potential anti-invasive effects of EPE in MPM therapy treatment.

Obesity, defined as abnormal or excessive fat accumulation, is currently believed to be a major public health problem worldwide. Over the past 20 years, the prevalence of obesity has increased rapidly in both industrialized and developing countries, resulting in a considerably increased risk of type 2 diabetes mellitus (T2DM) and metabolic syndrome. Although the exact pathophysiological mechanisms underlying these diseases remain unclear, clinical and epidemiological studies support the existence of a relationship between obesity-induced inflammation and insulin resistance linked with the development and progression of metabolic diseases. Adipokines, produced and released by adipose tissue, are considered as factors linking obesity-induced inflammation with insulin resistance, and their regulation through peroxisome proliferator-activated receptors γ (PPARγ also known as NR1C3) is essential in these processes. PPARγ are transcriptional factors belonging to the ligand-activated nuclear receptor superfamily which directly regulate the expression of a large number of genes involved in adipocyte differentiation, lipid and carbohydrate metabolism as well as adipokine synthesis; thereby they are implicated in various metabolic disorders, including obesity, insulin resistance, dyslipidemia, and hypertension. This review summarizes the current literature on a functional relationship of PPARγ with obesity and insulin resistance and, moreover, highlights the significance of synthetic ligands of these receptors in the mentioned metabolic disorders.