Induction of Apoptosis and Antiproliferative Activity of Naringenin in Human Epidermoid Carcinoma Cell through ROS Generation and Cell Cycle Arrest

A natural predominant flavanone naringenin, especially abundant in citrus fruits, has a wide range of pharmacological activities. The search for antiproliferative agents that reduce skin carcinoma is a task of great importance. The objective of this study was to analyze the anti-proliferative and apoptotic mechanism of naringenin using MTT assay, DNA fragmentation, nuclear condensation, change in mitochondrial membrane potential, cell cycle kinetics and caspase-3 as biomarkers and to investigate the ability to induce reactive oxygen species (ROS) initiating apoptotic cascade in human epidermoid carcinoma A431 cells. Results showed that naringenin exposure significantly reduced the cell viability of A431 cells (p<0.01) with a concomitant increase in nuclear condensation and DNA fragmentation in a dose dependent manner. The intracellular ROS generation assay showed statistically significant (p<0.001) dose-related increment in ROS production for naringenin. It also caused naringenin-mediated epidermoid carcinoma apoptosis by inducing mitochondrial depolarization. Cell cycle study showed that naringenin induced cell cycle arrest in G₀/G₁ phase of cell cycle and caspase-3 analysis revealed a dose dependent increment in caspase-3 activity which led to cell apoptosis. This study confirms the efficacy of naringenin that lead to cell death in epidermoid carcinoma cells via inducing ROS generation, mitochondrial depolarization, nuclear condensation, DNA fragmentation, cell cycle arrest in G₀/G₁ phase and caspase-3 activation.     

Detection and characterization of mutations in genes related to isoniazid resistance in Mycobacterium tuberculosis clinical isolates from Iran

Molecular Biology Reports - The global rise in drug-resistant Mycobacterium tuberculosis (M.tb), and especially the significant prevalence of isoniazid (INH)-resistance constitute a significant...     

Bi-directional PCR allele-specific amplification (bi-PASA) for detection of caspase-8 -652 6N ins/del promoter polymorphism (rs3834129) in breast cancer

Caspase-8 (CASP8) plays a critical role in regulating apoptosis, and its functional polymorphisms may modify cancer risk. We investigated the possible association between CASP8 -652 6N ins/del (rs3834129) and the risk of breast cancer in a sample of Iranian population. This case-control study was done on 236 breast cancer patients and 203 cancer free healthy female. We designed a rapid and simple bi-directional PCR allele-specific amplification (bi-PASA) for detection of CASP8 -652 6N ins/del polymorphism. The results showed that the CASP8 -652 6N del/dl genotype was inversely associated with breast cancer risk (OR=0.33, 95% CI=0.17-0.65, p=0.001). The frequencies of the del allele in cases and controls were 29.1% and 38.6%, respectively. An inverse association between CASP8 6N del variant and the risk of breast cancer (OR=0.66, 95% CI=0.66-0.87, p=0.002) was found. In conclusion, the result suggests that the CASP8 -652 6N del polymorphism plays a protective role in susceptibility to breast cancer in our population. Further studies in other populations with larger samples are needed to confirm these findings.     

Establishing human lacrimal gland cultures with secretory function

Purpose

Dry eye syndrome is a multifactorial chronic disabling disease mainly caused by the functional disruptions in the lacrimal gland. The treatment involves palliation like ocular surface lubrication and rehydration. Cell therapy involving replacement of the gland is a promising alternative for providing long-term relief to patients. This study aimed to establish functionally competent lacrimal gland cultures in–vitro and explore the presence of stem cells in the native gland and the established in-vitro cultures.

Methods

Fresh human lacrimal gland from patients undergoing exenteration was harvested for cultures after IRB approval. The freshly isolated cells were evaluated by flow cytometry for expression of stem cell markers ABCG2, high ALDH1 levels and c-kit. Cultures were established on Matrigel, collagen and HAM and the cultured cells evaluated for the presence of stem cell markers and differentiating markers of epithelial (E-cadherin, EpCAM), mesenchymal (Vimentin, CD90) and myofibroblastic (α-SMA, S-100) origin by flow cytometry and immunocytochemistry. The conditioned media was tested for secretory proteins (scIgA, lactoferrin, lysozyme) post carbachol (100 µM) stimulation by ELISA.

Results

Native human lacrimal gland expressed ABCG2 (mean±SEM: 3.1±0.61%), high ALDH1 (3.8±1.26%) and c-kit (6.7±2.0%). Lacrimal gland cultures formed a monolayer, in order of preference on Matrigel, collagen and HAM within 15–20 days, containing a heterogeneous population of stem-like and differentiated cells. The epithelial cells formed ‘spherules’ with duct like connections, suggestive of ductal origin. The levels of scIgA (47.43 to 61.56 ng/ml), lysozyme (24.36 to 144.74 ng/ml) and lactoferrin (32.45 to 40.31 ng/ml) in the conditioned media were significantly higher than the negative controls (p<0.05 for all comparisons).

Conclusion

The study reports the novel finding of establishing functionally competent human lacrimal gland cultures in-vitro. It also provides preliminary data on the presence of stem cells and duct-like cells in the fresh and in-vitro cultured human lacrimal gland. These significant findings could pave way for cell therapy in future.     

Effects of decreased glutathione peroxidase activity on the pentose phosphate cycle in mouse lung

The effects of reducing glutathione peroxidase activity in the lung by changing dietary selenium intake has been investigated. In animals that were exposed to room air, selenium effects were confined to glutathione peroxidase activity, whereas under conditions of oxidant stress (ozone) the decrease in glutathione peroxidase activity prevented the stimulation of the pentose phosphate cycle (assayed by measuring glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities) which has been reported to increase in response to oxidant stress. The suppression of glutathione peroxidase activity was found to depend on dietary selenium concentration. The physiological significance of this observation may be related to the process of injury and repair in the lung.     

Evaluation of antigenotoxicity effects of umbelliprenin on human peripheral lymphocytes exposed to oxidative stress

The protective properties of a prenylated coumarin, umbelliprenin (UMB), on the human lymphocytes DNA lesions were tested. Lymphocytes were isolated from blood samples taken from healthy volunteers. DNA breaks and resistance to H₂O₂-induced damage were measured using a single-cell microgel electrophoresis technique under alkaline conditions (comet assay). Human lymphocytes were incubated in UMB (10, 25, 50, 100, 200, and 400 μM) alone or a combination of different concentrations of UMB (10, 25, 50, 100, 200, and 400 μM) and 25 μM H₂O₂. Untreated cells, ascorbic acid (AA; 25, 50, 100, 200, and 400 μM) and H₂O₂ (25 μM) were considered as negative control, positive control, and the standard antioxidant agent for our study, respectively. Single cells were analyzed with “TriTek Cometscore version 1.5” software. The DNA damage was expressed as percent tail DNA. UMB exhibited a concentration-dependent increase in protection activity against DNA damage induced by 25 μM H₂O₂ (from 67.28% to 39.17%). The antigenotoxic activity of AA, in the range 0–50 μM, was greater than that of UMB. However, no significant difference (p > 0.05) in the protective activity was found between UMB and AA at concentrations of approximately higher than 50 μM.     

Remediation of Gulf War Oil Spill Contaminated Soil by a Subcritical Water Extraction Process: Oil Removal,Recovery, and Degradation

Due to the unique properties of subcritical water (marked change in water's dielectric constant and viscosity), the extraction by subcritical water offers a great opportunity to remediate soil contaminated with organic pollutants as an alternative and green remediation method. In this study, subcritical water extraction is proposed as an efficient remediation technique for the Gulf War oil spill contaminated soil. The subcritical water extraction experiment was carried out in a lab-scale continuous flow apparatus. The three major operating factors, temperature, time and water flow rate, were evaluated in terms of optimum removal efficiency. The results show that crude oil removal depended largely on water temperature, whereas an extraction run time higher than 1 h and a water flow rate higher than 1.5 mL/min marginally or negatively affected removal efficiency. During subcritical water treatment at 300°C for 1 h at a flow rate of 1.5 mL/min, removal efficiency was almost 95%. Under these operating conditions, the subcritical water treatment demonstrated a similar removal efficiency to those of organic solvents like acetone. In contrast, the efficiency of oil recovery decreased with an increase in extraction temperature, due to degradation by a water self-oxidizing agent. Several degradation products identified in the treated soil and in the effluent sample (which initially were absent in the contaminated soil) were oxygen-containing aromatic compounds, confirming the oxidation-degradation.     

The investigation of the G-quadruplex aptamer selectivity to Pb2+ ion: a joint molecular dynamics simulation and density functional theory study

Abstract

The aptamers with the ability to form a G-quadruplex structure can be stable in the presence of some ions. Hence, study of the interactions between such aptamers and ions can be beneficial to determine the highest selective aptamer toward an ion. In this article, molecular dynamics (MD) simulations and quantum mechanics (QM) calculations have been applied to investigate the selectivity of the T30695 aptamer toward Pb²⁺ in comparison with some ions. The Free Energy Landscape (FEL) analysis indicates that Pb²⁺ has remained inside the aptamer during the MD simulation, while the other ions have left it. The Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) binding energies prove that the conformational stability of the aptamer is the highest in the presence of Pb²⁺. According to the compaction parameters, the greatest compressed ion-aptamer complex, and hence, the highest ion-aptamer interaction have been induced in the presence of Pb²⁺. The contact maps clarify the closer contacts between the nucleotides of the aptamer in the presence of Pb²⁺. The density functional theory (DFT) results show that Pb²⁺ forms the most stable complex with the aptamer, which is consistent with the MD results. The QM calculations reveal that the N-H bonds and the O…H distances are the longest and the shortest, respectively, in the presence of Pb²⁺. The obtained results verify that the strongest hydrogen bonds (HBs), and hence, the most compressed aptamer structure are induced by Pb²⁺. Besides, atoms in molecules (AIM) and natural bond orbital (NBO) analyses confirm the results.

Communicated by Ramaswamy H. Sarma