Árpád Szántó

PARP-1 inhibition-induced activation of PI-3-kinase-Akt pathway promotes resistance to taxol

PARP inhibitors combined with DNA-damage inducing cytostatic agents can lead to effective tumor therapy. However, inhibition of poly(ADP-ribose) polymerase (PARP-1; EC 2.4.2.30) induces the activation of PI-3-kinase-Akt pathway, which can counteract the effectiveness of this therapy. To understand the role of Akt activation in the combined use of cytostatic agent and PARP inhibition, we used taxol (paclitaxel) as an antineoplastic agent, which targets microtubules and up-regulates mitochondrial ROS production, together with (i) pharmacological inhibition (PJ-34), (ii) siRNA knock-down and (iii) transdominant expression of the DNA binding domain of PARP-1. In all cases, PARP-1 inhibition leads to suppressed poly-ADP-ribosylation of nuclear proteins, prevention of NAD(+) depletion and significant resistance against taxol induced caspase-3 activation and apoptotic cell death. Paclitaxel induced a moderate increase in Akt activation, which was significantly augmented by PARP inhibition, suggesting that PARP inhibition-induced Akt activation could be responsible for the cytostatic resistance. When activation of the PI-3-kinase-Akt pathway was prevented by LY-294002 or Akt Inhibitor IV, the cytoprotective effect of PARP inhibition was significantly diminished showing that the activation of PI-3-kinase-Akt cascade had significantly contributed to the cytostatic resistance. Our study demonstrates that drug-induced drug resistance can be responsible for the reduced efficacy of antitumor treatment. Although inhibition of PARP-1 can promote cell death in tumor cells by the inhibition of DNA repair, PARP-inhibition promoted activation of the PI-3-kinase-Akt pathway can counteract this facilitating effect, and can cause cytostatic resistance. We suggest augmenting PARP inhibition by the inhibition of the PI-3-kinase-Akt pathway for antitumor therapy.

Laparoscopic Repair of Circumcaval Ureter: One-year Follow-up of Three Patients and Literature Review

OBJECTIVES To describe our experience and 1-year follow-up of 3 patients with circumcaval ureter (CU) treated laparoscopically, with the introduction of a new stenting method and review of the published data. Because of its rarity, more reports are needed to advocate more comprehensive knowledge about the preferred surgical technique for the treatment of CU. METHODS Since November 2005, 3 patients with symptomatic CU have undergone laparoscopic repair of their anomaly at our institutes. In all 3 cases, the ureter was transected and positioned anteriorly with an end-to-end anastomosis. In 2 cases, the retrocavally located ureteral segment was resected. RESULTS The mean operative time in our series was 210 minutes, without any intraoperative or early postoperative complications. In 1 patient, a slight ureteral stricture was detected that resolved with reinsertion of a double-J stent. Histopathologic examination of the resected ureteral segments revealed sclerosis and muscular hypertrophy. All patients remained symptom free during the 1 year of follow-up. CONCLUSIONS With all the advantages of a minimally invasive procedure and preserving therapeutic efficacy, the laparoscopic approach should be considered a standard choice for surgical treatment of CU in symptomatic patients. Care should be taken to diagnose and excise the pathologically narrowed ureteral segment.

Thymic Atrophy and Apoptosis of CD4+CD8+ Thymocytes in the Cuprizone Model of Multiple Sclerosis.

Previous studies on the degenerative animal model of multiple sclerosis suggested that the copper-chelator cuprizone might directly suppress T-cell functions. Peripheral T-cell function in the cuprizone model has already been explored; therefore, in the present study, we investigated, for the first time, how cuprizone feeding affects the thymus, the organ of T-cell maturation and selection. We found that even one week of cuprizone treatment induced significant thymic atrophy, affecting the cortex over the medulla. Fluorescent microscopy and flow-cytometric analyses of thymi from cuprizone- and vehicle-treated mice indicated that eradication of the cluster of the differentiation-4 (CD4)-CD8 double-positive T-cell subset was behind the substantial cell loss. This result was confirmed with CD3-CD4-CD8 triple-staining experiments. Ultrastructurally, we observed degraded as well as enlarged mitochondria, myelin-bodies, large lipid droplets, and large lysosomes in the thymi of cuprizone-treated mice. Some of these features were similar to those in physiological and steroid-induced accelerated aging. According to our results, apoptosis was mainly of mitochondrial origin mediated by both caspase-3- and apoptosis inducing factor-mediated mechanisms. Additionally, mitogen activated protein kinase activation and increased pro-apoptotic B cell lymphoma-2 family protein expression were the major underlying processes. Our results do not indicate a functional relationship between cuprizone-induced thymus involution and the absence of inflammatory responses or the selective demyelination observed in the cuprizone model. On the other hand, due to the reversible nature of cuprizone’s deleterious effects, the cuprizone model could be valuable in studying thymus regeneration as well as remyelination processes.

Desethylamiodarone—A metabolite of amiodarone—Induces apoptosis on T24 human bladder cancer cells via multiple pathways

Bladder cancer (BC) is a common malignancy of the urinary tract that has a higher frequency in men than in women. Cytostatic resistance and metastasis formation are significant risk factors in BC therapy; therefore, there is great interest in overcoming drug resistance and in initiating research for novel chemotherapeutic approaches. Here, we suggest that desethylamiodarone (DEA)–a metabolite of amiodarone—may have cytostatic potential. DEA activates the collapse of mitochondrial membrane potential (detected by JC-1 fluorescence), and induces cell death in T24 human transitional-cell bladder carcinoma cell line at physiologically achievable concentrations. DEA induces cell cycle arrest in the G0/G1 phase, which may contribute to the inhibition of cell proliferation, and shifts the Bax/Bcl-2 ratio to initiate apoptosis, induce AIF nuclear translocation, and activate PARP-1 cleavage and caspase-3 activation. The major cytoprotective kinases—ERK and Akt—are inhibited by DEA, which may contribute to its cell death-inducing effects. DEA also inhibits the expression of B-cell-specific Moloney murine leukemia virus integration site 1 (BMI1) and reduces colony formation of T24 bladder carcinoma cells, indicating its possible inhibitory effect on metastatic potential. These data show that DEA is a novel anti-cancer candidate of multiple cell death-inducing effects and metastatic potential. Our findings recommend further evaluation of its effects in clinical studies.

Cytoplasmic expression of β-catenin is an independent predictor of progression of conventional renal cell carcinoma: a simple immunostaining score.

The aims of this study were to investigate the potential of β‐catenin as a biomarker for predicting cancer‐specific survival, and to find a reproducible mode of evaluation of immunohistochemistry.

Linalool-induced oxidative stress processes in the human pathogen Candida albicans

The present study investigated the linalool (Lol)-induced effects in acute toxicity tests in the human pathogen Candida albicans (C. albicans). Lol treatments induced reduced germ tube formation of the pathogen, which plays a crucial role in the virulence. In comparison with the untreated control, the exposure of 107 cells ml-1 to 0.7 mM or 1.4 mM Lol for one hour induced 20% and 30% decrements, respectively, in the colony-forming ability. At the same time, these treatments caused dose-dependent decrease in the levels of superoxide anion radical and total reactive oxygen species, while there was 1.5 and 1.8-fold increases in the concentrations of peroxides and lipid peroxides, respectively, indicating oxidative stress induction in the presence of Lol. Lol treatments resulted in different adaptive modifications of the antioxidant system. In 0.7 mM-treated cells, decreased specific activities of superoxide dismutase and catalase were detected, while exposure to 1.4 mM Lol resulted in the up-regulation of catalase, glutathione reductase and glutathione peroxidases.

Shift of Keratin Expression Profile in End-stage Kidney Increases the Risk of Tumor Development

Background/Aim: Pre-neoplastic lesions and renal cell tumors of distinct pheno- and genotypes occur frequently in end-stage kidneys. The aim of this study was to investigate the role of KRT7 and KRT19 in this process, the expression of which was previously detected by Affymetrix GeneChip analysis. Patients and Methods: Twelve end-stage kidneys were analyzed to find pre-neoplastic lesions and tumors and expression of KRT7 and KRT19 was examined by immunohistochemistry. Results: A total of 17 tumors, 149 pre-neoplastic lesions, 179 simple or proliferative cysts >2 mm were identified. Diffuse expression of KRT7 and KRT19 was seen in all end-stage kidneys as well as in the vast majority of cysts, pre-neoplastic lesions and tumors. Conclusion: Our data indicates that de novo expression of KRT7 and KRT19 resulting in altered plasticity and stem cell characteristics of epithelial cells might be a crucial factor in increasing the risk of tumor development in end-stage kidneys.

Prevalence and Type Diversity of Human Papillomaviruses in Penile Cancers in Hungary

To the editor Penile cancers are one of the rare forms of oncological diseases as in developed countries their prevalence is less than 1 %. Epidemiological studies suggested the role of oncogenic HPV-types as a causative agent of penile tumors [1, 2]. Around 40 % of patients with penile cancer had also been affected by HPV with type 16 being the most prevalent [3]. Currently available literature data explain HPV-induced tumors with the integration of virus into the epithelial cells’ genome, and its genetic manipulation of the host DNA. Another interesting fact is that HPV infection is much more frequently associated with certain types of penile cancers, than other malignant manifestations [3]. Clinical course and prognosis of patients with penile cancer is unequivocally determined by the lymphatic node status. Five year survival rate of pathologically negative lymph nodes (pN0) is 85–100 %, whereas the involvement of pathologically verified metastatic lymph nodes in the inguinal region dramatically reduces this rate [4]. A retrospective study including 145 male patients describes: tumor thickness and lymphatic or vascular invasion as prognostic factors for lymph node involvement. Interestingly, no statistical correlations can be indicated in lymphatic involvement in connection with T status and the grade of cancer [5]. The aims of the present study were i) to identify and estimate the prevalence of high-risk HPV (hrHPV) genotypes in both primary penile tumors and metastatic lymph nodes, ii) to analyse the potential correlation between the hrHPV positivity and the severity and progression of the cancer. Tissue samples were taken from both the primary tumor and the regional lymph nodes, in over the course of operations of penile cancers in the Department of Urology, University of Pécs, Hungary, between 2002 and 2012. Samples were forwarded to histopathological processing where tissues were fixed in formalin and embedded into paraffin for histological processing. For retrospective molecular studies, 10 μm sections of the paraffin blocks were deparaffinated. Subsequently, DNAwas extracted for the purpose of HPV-identification. Cells were disintegrated using TissueLyser (Qiagen), and subcellular structures were digested enzymatically using Proteinase-K. DNA was purified from tissues using QIAmp DNA FFPE Tissue Kit (Qiagen), according to the manufacturer’s recommendations. HPV DNA was detected by virus-specific TaqMan PCR (DIAGON Ltd., Hungay). In case of HPV positive samples Linear Array HPV Genotyping Test (Roche) was further used for genotyping. A total of 35 patients were involved in the current clinical study. High-risk HPV was identified from primary tumors in 17 cases (48.5 %), regional (inguinal) lymph nodes were positive in 3 cases. The average age of hrHPV positive males was 55 years (range: 44–87 years) while HPV negative patients were slightly older, averaging 66 years of age (range: 50– 82 years). Genotyping using high-sensitivity molecular assays was available for 14 cases out of the 17 hrHPV-positive patients. HPV 16 was identified in 11 of 14 samples (78.5 %), HPV 59 and 82 were detected in two separate cases, while * Ferenc Jakab jakabf@gamma.ttk.pte.hu