Background: Organic solvents are widely used in cell biology experiments. Despite increasing the solubility, they have some moderate toxic effects. Therefore, selecting the appropriate solvent along with the use of suitable concentration insures the accuracy and reliability of experimental results. Objectives: The current study aimed to examine the cytotoxic effects of some organic solvents on various cell models including MCF-7, RAW-264.7 and human umbilical vein endothelial cells (HUVEC). Materials and Methods:To evaluate the cytotoxicity effect of common organic solvents on the MCF-7, RAW-264.7 and HUVEC cells, multi-table tournament (MTT) colorimetric assay, the widely used and validated cytotoxicity test was applied. For this purpose, the selected cells were treated with different concentrations (0, 0.1%, 0.5%, 1%, 1.5%, 2%, 3% and 5% v/v) of four most commonly used organic solvents (acetone, ethanol, dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) and then subjected to MTT experiment. Results: According to the obtained results, the cytotoxicity increased significantly with increasing the concentration of all four solvents compared to that of the control group. Studies with MCF-7, RAW-264.7 and HUVEC suggested that acetone, ethanol and DMSO at concentrations of 0.1% and 0.5%, had little or no toxicity, whereas higher concentrations inhibited the growth of all three cells. Compared with other three solvents, DMF displayed rather greater toxicity. Based on the results, proliferation of MCF-7, RAW-264.7 and HUVEC cells were inhibited by all used organic solvents, dose dependently. Conclusions: Thus, the background experimental error can be reduced remarkably by maximal concentration of 0.5% ethanol, acetone and DMSO and 0.1% DMF in the final treatment medium.

In the past decade, miRNAs have been extensively attracted the scientist's attentions as tumor suppressors or oncogenes that have been implicated in tumor progression, metastasis and intrinsic resistance to various cancer therapies. microRNA-21 (miR-21) demonstrates a potential oncogenic function and targets tumor inhibitor proteins in almost all types of cancer. miR-21 overexpression has been studied in terms of cell proliferation, migration, invasion, metastasis, and apoptosis regulation. Inhibition of miRNA expression using antisense technology by various nanovectors of different sizes, shapes and compositions has been evolved progressively to overcome the barriers confronted by miRNA delivery. Application of miR-21 antisense oligonucleotides for treating cancerous cells has become a promising achievement for cancer therapy. Moreover, miR-21 can mediate resistance to radiation and chemotherapy. The expanding role of miR-21 functions in human cancers with an emphasis on its regulatory targets and mechanisms, miR-21 related achievements against cancer promotion have been discussed.

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A comparison of the two most famous groups of calcium-regulated photoproteins, cnidarians and ctenophores, showed unexpectedly high degree of structural similarity regardless of their low sequence identity. It was suggested these photoproteins can play an important role in understanding the structural basis of bioluminescence activity. Based on this postulate, in this study the cDNA of mnemiopsin from luminous ctenophore Mnemiopsis leidyi was cloned, expressed, purified and sequenced. The purified cDNA, with 621 base pairs, coded a 206 residues protein. Sequence of mnemiopsin showed 93.5 and 51% similarity to other ctenophore proteins and cnidarians, respectively. The cDNA encoding apo-mnemiopsin of M. leidyi was expressed in Escherichia coli. The purified apo-protein showed a single band on SDS-PAGE (molecular weight ~27 kDa). A semi-synthetic mnemiopsin was prepared using coelenterazine and EDTA and its luminescence activity was measured in the presence of CaCl(2). The results showed an optimum pH of 9.0 and lower calcium sensitivity compared to aequorin. Comparison of amino acid residues in substrate binding site indicated that binding pocket of ctenophores contains less aromatic residues than cnidarians. This can lead to a decline in the number of stacking interactions between substrate and protein which can affect the stability of coelenterazine in binding cavity. Structural comparison of photoproteins with low sequence identity and high 3D structural similarity, can present a new insight into the mechanism of light emission in photoproteins.

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Context:Stachys pilifera Benth (Lamiaceae) has long been used to treat infectious diseases, respiratory and rheumatoid disorders in Iranian folk medicine. Antitumor and antioxidant activity of the plant have been reported.Objective: The study was designed to assess the hepatoprotective activity of ethanol extract of Stachys pilifera in carbon tetrachloride (CCl4)-induced hepatotoxicity in rats.Materials and methods: The rats were randomly divided into six equal groups (n = 7). Group I was treated with normal saline; Group II received CCl4 (1 mL/kg. i.p., twice a week) for 60 consecutive days; Groups III, IV and V were given CCl4 plus Stachys pilifera (100, 200 and 400 mg/kg/d,p.o.); Group VI received the extract (400 mg/kg/d, p.o.). Histopathological analysis and measurement of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), malondialdehyde (MDA), total protein (TP) and albumin (ALB) were performed.Results: CCl4 caused a significant increase in the serum levels of AST, ALT, ALP and MDA as well as decreased ALB, and TP serum levels (p < 0.001). The extract (200 and 400 mg/kg/d) significantly normalized the CCl4-elevated levels of ALT, AST, ALP and MDA (p < 0.001). The extract (200 and 400 mg/kg/d) also increased the serum levels of TP compared to CCl4 group (p< 0.01). The extract (200 and 400 mg/kg/d) also decreased the histological injuries (inflammation and fatty degeneration) by CCl4.Discussion: The results revealed that the Stachys pilifera extract could provide considerable protection against CCl4 hepatotoxicity in rats that may be related to its antioxidant properties.

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Stachys pilifera (S. pilifera) Benth (Lamiaceae) is used in traditional medicine to treat a variety of diseases. Despite some reports on the antitumor effects of some species of this genus, anticancer activity of S. pilifera has not been yet reported. Here, we examined the cytotoxic effect and cell death mechanisms of methanolic extract of S. pilifera and its alkaloid and terpenoid fractions on the HT-29 colorectal cell line. HT-29 cells were cultivated and then incubated in the methanolic extract of S. pilifera and its fractions at various concentrations for 24 h. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Morphology of cells was evaluated by contrast microscopy. Furthermore, effects of the tested extract and fractions were tested on some regulators of cell death and proliferation such as caspase-8, caspase-9, nuclear factor-κB (NF-κB), and nitric oxide (NO). Cisplatin was used as positive control. The estimated IC50 values of the methanolic extract, alkaloid and terpenoid fractions, and cisplatin against HT29 cell after 24 h were determined to be 612, 48.12, 46.44, and 4.02 μg/mL, respectively. Morphological changes such as plasma membrane blebbing, cell size reduction, and apoptotic bodies were observed in cells faced with the extract and fractions. S. pilifera extract and its fractions induced apoptosis through inhibition of NF-κB, NO, and activation of caspase-8 and caspase-9. Data showed considerable cytotoxic and antiproliferative effects of S. plifera on colorectal cell line through induction of apoptosis. These findings provide a basis for the therapeutic potential of S. pilfera in the treatment of colon cancer.