Intracellular GSH Alterations and Its Relationship to Level of Resistance following Exposure to Cisplatin in Cancer Cells.

One of the major complications in cancer chemotherapy with cisplatin as one of the important medicines in treatment regimens of different cancers is the development of resistance. One of the most described cellular defense mechanisms involved in resistance is glutathione (GSH), thus in this study, the effects of cisplatin on the total intracellular GSH level (GSHi) in some sensitive and resistant variants of human cell lines (hepatocarcinoma HepG2, skin A375, cisplatin sensitive glioblastoma U373MG and cisplatin resistant glioblastoma U373MGCP, cisplatin sensitive ovary A2780S and cisplatin resistant A2780CP cells) were studied. MTT assay was performed to measure cytotoxicity of cisplatin (33.3 µM for 1 hour). Following cisplatin exposure, GSHi (per million cells) was evaluated using a photometrical assay up to 90 minutes. Our results indicate that there are significant differences between GSHi content of A2780CP and U373MGCP cells compared to other cell lines. Moreover, IC50 of cisplatin in different cells seems to have a relation with mean of GSH level in 90 minutes (GSH (mean)90). As a conclusion, it seems that resistance to cisplatin in different cell lines is more related with the diverse patterns of GSHi variations following cisplatin exposure than its original level, and/or its cellular increase or decrease. It is also suggested that GSH (mean)90 may be used as a factor for the prediction of cellular resistance to cisplatin.

Antiviral and cytotoxic evaluation of coumarins from Prangos ferulacea.

CONTEXT: Prangos ferulacea (L.) Lindl. (Apiaceae) is a perennial plant found in the Middle-East, where it is commonly used as an antispasmodic and anti-inflammatory agent. It is a rich source of coumarins. OBJECTIVE: To purify several coumarins from P. ferulacea and to screen their cytotoxicity and anti-herpes activity. MATERIALS AND METHODS: Acetone extract of roots of P. ferulacea was subjected to several chromatographic separations to render pure coumarins (1-8). Anti-herpes virus effects of 1-7 were evaluated at concentration 2.5, 5, and 10 µgmL(-1), on a confluent monolayer of Vero cells infected with 25 PFU of HSV1. Cytotoxic effects of 1 and 2 were evaluated on an A2780S cell line using the MTT assay. The cells were exposed to a series of concentrations of coumarins (0.01-2.5 mM, 37°C, 72 h). RESULTS: Compounds 1-8 were identified as osthole, isoimperatorin, oxypeucedanin, psoralen, oxypeucedanin hydrate, gosferol, oxypeucedanin methnolate, and pranferol. This is the first report of occurrence of 4 and 7 in this plant. Compound 1 showed a viability of 9.41% ± 2.4 at 2.5 mM on A2780S cells (IC50 = 0.38 mM). The cell survival of 2 at 2.5 mM was 46.86% ± 5.5 with IC50 equal to 1.1 mM. DISCUSSION AND CONCLUSION: Compound 1 shows cytotoxic effects on the A2780S cell line. Compound 2 is a cyclooxygenase-2 inhibitor and the A2780S cell line does not express COX-2 which may interpret the non-toxic effect of the compound on this cell line. None of the tested compounds showed an anti-HSV effect at non-toxic concentrations.

In vitro cytotoxic evaluation of some synthesized COX-2 inhibitor derivatives against a panel of human cancer cell lines.

Celecoxib is a non-steroidal anti-inflammatory drug (NSAID) developed as a selective inhibitor of cyclooxygenase-2 (COX-2) for the treatment of rheumatoid arthritis disease. Recently some other mechanisms have been identified for anti cancer activity of these agents including induction of apoptosis, inhibition of tumor vascularization, stimulation of antitumor immune responses and inhibition of cellular protein synthesis. The cytotoxic effects of four synthesisized analogues of celecoxib (coded as D, E, F and G) were evaluated against Hela, MDA-MB-231, A-2780-s and HT-29 cancer cells, using MTT assay; Also their induction of apoptosis using DNA fragmentation analysis were studied. MTT assay showed that cell survival percent of COX-2 positive cell lines (HT-29, MDA-MB-231 and Hela; p≤0.05) were decreased significantly after exposure to the tested COX-2 inhibitors while little effect was observed on the COX-2 negative cell line (A-2780-s). Results also showed that A-2780-s and Hela were the most resistant and the most sensitive cell lines to these compounds, respectively. Moreover, in DNA fragmentation assay, induction of apoptosis was confirmed by electrophoretic pattern of separated DNA fragments in Hela cell line. Compounds E and G in comparison with D and F exerted more cytotoxic effect on COX-2 positive cell lines (Hela, HT-29 and MDA-MB-231). This could be due to the hydrophobic substituent (Cl, CH3) located at the para position of phenyl ring leading to more lipophilicity and cell uptake. In addition, these COX-2 inhibitors induced apoptosis on Hela cell-line, which could be considered as one of the cytotoxic mechanisms of these compounds as potential anti cancer agents.