Fotini Papachristou

Supplementation of melatonin protects human lymphocytes in vitro from the genotoxic activity of melphalan.

Melatonin (MLT) is a natural oncostatic factor of the human body as well as an antioxidant thus protects the nuclear DNA from oxidative damage. It also has the ability to reduce the side effects of various drugs when used as a combination therapy. The anti-neoplastic agent melphalan (MEL), which encompasses a number of side effects, is a strong alkylating agent and a potent inducer of sister chromatid exchanges (SCEs). The aim of the current in vitro study was to investigate the ability of MLT to reduce the genotoxic effect of MEL on normal human cultured peripheral lymphocytes. Cells were treated with both agents at various concentrations (MLT 100, 200 and 400 microM and MEL 330, 490 and 650 nM) and incubated for 72 h prior harvesting. The levels of cytostaticity, cytotoxicity and genotoxicity were qualitatively evaluated using the proliferation rate index, the mitotic index and the SCE methodology, respectively. Our results demonstrated the protective effect of MLT on cells treated with MEL in vitro. The greatest protective effect of MLT at 100 and 400 microM was illustrated against 330 nM of MEL in comparison with all other doses of MEL. These observations imply that MLT may be proved useful in reducing some of the toxic effects associated with certain classes of chemotherapeutic agents and other chemical and physical mutagens and carcinogens, acting both as an antioxidant-radical scavenger and a protective mechanism against cellular damage due to exposure to free radical-producing agents. It is essential to investigate substances with protective properties which are normally produced from the human body.

Mycotoxins' Activity at Toxic and Sub-Toxic Concentrations: Differential Cytotoxic and Genotoxic Effects of Single and Combined Administration of Sterigmatocystin, Ochratoxin A and Citrinin on the Hepatocellular Cancer Cell Line Hep3B

Food safety organizations indicate the likelihood of constant human and animal exposure to mycotoxin mixtures as a possible negative public health impact. Risk assessment demonstrates that certain mycotoxins of Aspergillus and Penicillium spp. are toxic and hold a significant genotoxic efficacy at nanomolar concentrations. The aim of the current study was to investigate the potential cytogenetic effects of sterigmatocystin (STER), ochratoxin A (OTA) and citrinin (CTN) alone or in combination, at pM to μΜ concentrations, on the human hepatocellular cancer cell line Hep3B. MTT reduction, mitotic divisions, cell cycle delays and sister chromatid exchange rates (SCE) were determined as endpoints of metabolic activity, cytotoxicity, cytostaticity, and genotoxicity, respectively. All mycotoxin treatments induce SCE rates from 10−12 M, while their cytotoxic and cytostatic potential varies. In PRI and MI assays, but not at MTT, STER alone or in combination with OTA + CTN appeared cytostatic and cytotoxic, even at 10−12 M, while CTN alone and all other combinations displayed substantial cellular survival inhibition in doses ≥ 10−8 M. Co-administration of STER + OTA or STER + CTN in concentrations ≤ 10−1 M, increased the MI and MTT activity, while it did not affect the PRI. Mycotoxin co-treatments revealed in general similar-to-additive or antagonistic genotoxic and cytotoxic effects. Our results for the first time describe that STER alone or in combination with OTA and/or CTN share a cytotoxic and cytogenetic potential even at picoMolar concentrations on human hepatoma cells in vitro.

The Effects of Apigenin on the Expression of Fas/FasL Apoptotic Pathway in Warm Liver Ischemia-Reperfusion Injury in Rats

Background. The aim of this experimental study was to investigate the role of apigenin in liver apoptosis, in an experimental model of hepatic ischemia-reperfusion in rats. Materials and Methods. Forty-eight Wistar rats (apigenin and control groups), 14 to 16 weeks old and weighing 220 to 350 g, were used. They were all subjected to hepatic ischemia by occlusion of the hepatic artery and portal vein for 45 minutes and reperfusion was followed for 60, 120, and 240 minutes. Apigenin was administrated intraperitoneally. Liver tissues were used for the detection of apoptosis by TUNEL assay and caspase 3 antibodies. Expression analysis of Fas/FasL genes was evaluated by real time PCR. Results. The expression analysis of Fas and FasL genes was increasing during reperfusion (significantly in the group of 240 minutes of reperfusion). It was in the same group that apigenin decreased Fas receptor levels and inhibited apoptosis as confirmed by TUNEL assay and caspase 3 antibodies. Conclusions. The effects of apigenin in the Fas/FasL mediated pathway of apoptosis, in the hepatic ischemia-reperfusion, seem to have a protective result on the hepatic cell.

Bacterial translocation in a rat model of large volume hepatic radiofrequency ablation.

BACKGROUND In this experimental study, we investigated the possibility of bacterial translocation, constituting a potential cause of infectious complications, after performing large volume hepatic radiofrequency ablation (RFA). MATERIALS AND METHODS Wistar rats were subjected to RFA of the left median liver lobe (approximately 28.5% of the liver volume) after midline laparotomy. At 30 min, 24 h, 48 h, 72 h or 1 wk postoperatively, (1) blood samples were collected from the portal and systemic circulation for assessment of endotoxin concentration, (2) tissue specimens were excised from mesenteric lymph nodes, non-ablated liver, pancreas, spleen, kidneys, and lungs for bacterial culture, and (3) segments of terminal ileum were excised for histopathologic examination, morphometric analysis, and apoptotic and mitotic rate estimation. At 1 and 48 h, ileal mucosa was collected for oxidative state assessment on the basis of glutathione to glutathione disulfate (GSH/GSSG) ratio. RESULTS Endotoxin levels were increased in both the portal and systemic circulation. Intestinal bacteria were isolated from all the organs at all time points. Ileal mucosa became gradually atrophic, with a decrease in villous height and density. There was an increase of crypt apoptotic rate, a decrease of GSH/GSSG ratio, while there were only mild signs of inflammation. CONCLUSIONS Large volume liver RFA in the rat resulted to endotoxemia and translocation of intestinal bacteria to proximal and distal to the intestine organs at both the early and late post-RFA periods. The intestinal mucosa barrier was disrupted as suggested by ileal mucosal atrophy, increased crypt apoptosis, and induction of oxidative stress.

Corticotropin-Releasing Hormone Receptors Mediate Opposing Effects in Cholestasis-Induced Liver Cell Apoptosis

CRH receptors are expressed in human and rat liver. The current study investigated the biological role of the CRH system in the hepatocellular apoptotic process and aimed to reveal the responsible molecular mechanisms. Using a rat experimental model of common bile duct surgical ligation leading to obstructive jaundice and cholestasis, liver apoptosis was induced in the hepatic parenchyma as confirmed by the elevated expression of the early apoptotic neoepitope M30. This effect was reversed by administration of the nonselective CRH antagonist astressin but not by the selective CRH(2) antagonist astressin2B, suggesting that antagonism of the endogenous CRH(1) blocked the cholestasis-induced apoptotic mechanism. No effect was observed in the noncholestasis controls. In our experimental model, early and late apoptosis-preventing markers were induced in parallel to apoptosis; elevated gene transcript levels of the anti-apoptotic bcl-2 were found by real-time PCR in the first postoperative day and increased serum hepatocyte growth factor levels were measured by ELISA in the third postoperative day. Selective CRH(2) antagonism reversed the elevated expression of bcl-2 and hepatocyte growth factor, suggesting that this receptor type mediated antiapoptotic actions of the endogenous CRH system, opposing the preapoptotic ones mediated by CRH(1). In conclusion, the present study indicated that the CRH neuroendocrine system regulates cholestasis-induced apoptosis in the hepatic parenchyma via receptor-specific pathways. These data may contribute to better understanding of the CRH biology and its pathophysiological significance in the periphery.

Antineoplastic and cytogenetic effects of chlorpromazine on human lymphocytes in vitro and on Ehrlich ascites tumor cells in vivo.

The inhibitory effect of phenothiazines in tumor growth and cancer cell proliferation in vitro and in vivo has been established. These reports motivated us to investigate the genotoxic, cytotoxic, and cytostatic potential of chlorpromazine, alone or in combination with mitomycin C, in vitro and in vivo. Sister chromatid exchange levels were assessed providing a quantitative index of genotoxicity. In-vitro studies were performed on human lymphocyte cultures and in-vivo studies involved Ehrilch ascites tumor (EAT) cells. An antitumour study was also conducted on the survival time and the ascitic volume in EAT-bearing Balb/C mice. The combination of chlorpromazine plus caffeine and mitomycin C exerted cytostatic and cytotoxic actions in human lymphocytes. The combination of chlorpromazine plus mitomycin C exerted cytostatic and cytotoxic actions in EAT cells, significantly increased the survival span of the mice inoculated with EAT cells, and suppressed the expected tumor growth increase. The findings of this basic study illustrate that high chlorpromazine concentrations increase chemotherapeutic effectiveness of mitomycin C. Chlorpromazine concentrations within the observed human plasma concentration range need to be tested along with antineoplastic agents in vitro for its synergistic action so as to evaluate a potential clinical application. Further investigation including other phenothiazines, biological systems, and cancer models is required.

Time course changes of anti- and pro-apoptotic proteins in apigenin-induced genotoxicity

BackgroundApigenin (4′,5,7-trihydroxyflavone, AP), an active component of many medicinal Chinese herbs, exhibits anticancer properties in vitro and in vivo. This study aims to investigate the genotoxic, cytostatic, and cytotoxic effects of AP and time course changes in the levels of anti- and pro-apoptotic proteins involved in the DNA damage response in HepG2 cells.MethodsThe genotoxic potential of AP was determined by sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) analysis. The levels of cytostaticity and cytotoxicity were evaluated by the proliferation rate and mitotic indices, respectively. MTT was used to study cytotoxicity, while the induction of apoptosis and the expression of apoptosis-related proteins were determined by ELISA.ResultsAt concentrations greater than 10 μM, AP decreased cell survival in a dose- (48 h: 10 vs. 20 μΜ, P < 0.001 and 20 vs. 50 μΜ, P = 0.005; 72 h: 10 vs. 20 μΜ, P < 0.001 and 20 vs. 50 μΜ, P = 0.001) and time-dependent manner (20 μΜ: 24 vs. 48 h, P < 0.001 and 48 vs. 72 h, P = 0.003; 50 μΜ: 24 vs. 48 h, P < 0.001 and 48 vs. 72 h, P < 0.001; 100 μΜ: 24 vs. 48 h, P < 0.001 and 48 vs. 72 h, P < 0.001). SCEs rates, cell proliferation, and mitotic divisions were also affected in a dose-dependent manner (P < 0.001). There was no change in the frequency of aberrant cells (1 μΜ ΑP: P = 0.554; 10 μM AP: P = 0.337; 20 μΜ AP: P = 0.239). Bcl-2 levels were reduced 3 h after AP administration (P = 0.003) and remained reduced throughout the 48 h observation period (6 h, P = 0.044; 12 h, P = 0.001; 24 h, P = 0.042; 48 h, P = 0.012). Bax and soluble Fas exhibited a transient upregulation 24 h after AP treatment. The Bax/Bcl-2 ratio was also increased at 12 h and remained increased throughout the 48 h observation period.ConclusionAP exhibited dose-dependent genotoxic potential in HepG2 cells. The protein levels of sFas, Bcl-2, and Bax were affected by AP to promote cell survival and cell death, respectively.

Serum profiles of M30, M65 and interleukin-17 compared with C-reactive protein in patients with mild and severe acute pancreatitis

Several studies state that a test of severity early in the course of acute pancreatitis is still needed. In this prospective study, an assay of the biomarkers M30 and M65 as well as of interleukin 17 (IL‐17) is investigated.

Soluble E-cadherin as a diagnostic and prognostic marker in gastric carcinoma.

ABSTRACT OBJECTIVE: Modifications in E-cadherin (E-Cad) expression are associated with dedifferentiation, progression, metastases and poor prognosis in many types of tumors. The aim of the present study was to identify a potential association of the pre- and post-operative soluble E-Cad levels (sE-Cad) with the clinicopathological parameters of patients with gastric cancer. PATIENTS AND METHODS: Serum sE-Cad levels were determined in 99 gastric cancer patients and 78 healthy volunteers using ELISA. RESULTS: Levels of sE-Cad were significantly increased in gastric cancer patients compared with these levels in healthy controls (p < 0.001). For the evaluation of the diagnostic significance of sE-Cad the area under the receiver operating characteristic (ROC) curve (AUC) was 0.835, while the optimal cut-off point of 9.9 μg/mL was determined to classify gastric cancer patients, which yielded sensitivity of 72.7%, specificity of 80.8% and accuracy of 76.3%. Poor differentiation (p = 0.009) and the presence of distant metastases (p < 0.001) were the two significant independent prognostic determinants for high sE-Cad levels in multivariate linear regression analysis. The preoperative levels of sE-Cad also proved helpful in classifying patients according to the choice treatment (curative versus palliative) (AUC, 0.656); when the optimal cut-off point was set at 17.60 μg/mL, the sensitivity was 57%, the specificity was 83% and accuracy was 75%. Survival was shorter in patients with increased sE-Cad (median, 7 months vs 39 months, p = 0.0002), although multivariate Cox regression analysis demonstrated a marginal prognostic significance of sE-Cad for survival (adjusted HR = 1.68, 95% CI = 0.93 to 3.02, p = 0.072). CONCLUSIONS: Serum sE-Cad levels could be considered as a diagnostic and prognostic marker in gastric cancer patients as well as a tool to select a treatment approach. The prognostic value of sE-Cad on overall survival requires further study. РЕЗЮМЕ ЦЕЛЬ: При многих типах опухолей изменения в экспрессии Е-кадерина связываются с дедифферен- цировкой, с развитием опухолей, метастазов и с плохим прогнозом. Настоящее исследование ставит себе целью найти возможные корреляции доопера- тивных и постоперативных уровней растворимого Е-кадерина с отдельными клиникопатологическими параметрами у пациентов с раком желудка. ПАЦИЕНТЫ И МЕТОДЫ: Сывороточные уровни растворимого Е-кадерина определены посредством энзимосвязанного иммуносорбентного теста (ELISA) у 99 пациентов с раком желудка и у 78 здоровых индивидов. РЕЗУЛЬТАТЫ: Уровни Е-кадерина оказались сигнифи- кантно повышенными у пациентов с раком желудка по сравнению с уровнями Е-кадерина у здоровых лиц (р < 0.001). Чтобы оценить диагностическое значение растворимого Е-кадерина измерена пло- щадь под кривой рабочей характеристики (ROS) - 0.835 при оптимальной пороговой стоимости (cut-off point) - 9.9 мкг/мл в целях категоризации пациентов с раком желудка. Кривая показала 72.7% чувствительности, 80.8% специфичности и 76.3% точности. Многофакторный линейный регрессионный анализ показал, что обе сигнификантные независи- мые прогностические детерминанты высоких уровней растворимого Е-кадерина это плохая дифференциа- ция (р = 0.009) и наличие отдаленных метастазов (р < 0.001). Дооперативные уровни растворимого Е-кадерина способствовали обнаружению пациентов с неоперабельным заболеванием, а также и пациен- тов, подвергнутых паллиативной резекции (площадь под кривой, 0.656); когда оптимальная пороговая стоимость (cut-off point) определена на 17.60 мкг/ мл, чувствительность - 57%, специфичность - 83%, а точность - 75%. Выживаемость меньшая у пациентов с повышенными уровнями Е-кадерина (7 мес./ 39 мес, р=0.0002), несмотря на то, что многофакторный регрессионный анализ Сох показал незначительную прогностическую сигнификантность растворимого Е-кадерина по этому показателю (корригированный HR = 1.68, 95% CI=0.93 до 3.02, р = 0.072). ВЫВОДЫ: Сывороточные уровни растворимой формы Е-кадерина могут служить диагностиче- ским и прогностическим маркером у пациентов с раком желудка, как и служить средством для идентификации выбранной терапии. Дополнительные исследования необходимы в целях оценки их прогно- стической стоимости для общей выживаемости.