ABSTRACT
Further phytochemical investigation of the aerial parts of Achillea clavennae has resulted in the isolation of three new sesquiterpene lactones: two highly oxygenated germacranolides (1, 2) and the iso-seco-guaianolide 9(R)-acetoxy-3-O-methyl-iso-seco-tanapartholide (3). Eight known compounds were also found, of which 9α-acetoxycanin (5), sintenin (6), and oleanolic acid (7) were detected for the first time. The structures of the isolated compounds were elucidated by combined spectroscopic methods (1D and 2D NMR, HRESIMS, CIMS, and FTIR). While the predominant metabolite germacranolide sintenin (6) was not cytotoxic, the new iso-seco-guaianolide (3) displayed cytotoxicity comparable to that of cisplatin and the lactone apressin (4), inducing partly apoptotic death in human U251 and rat C6 glioma cell lines.
Subject(s)
Achillea/chemistry , Antineoplastic Agents, Phytogenic/therapeutic use , Glioma/drug therapy , Phytotherapy , Plant Extracts/therapeutic use , Sesquiterpenes, Guaiane/therapeutic use , Animals , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis , Cell Line, Tumor , Humans , Hydralazine/chemistry , Hydralazine/isolation & purification , Molecular Structure , Oleanolic Acid/chemistry , Oleanolic Acid/isolation & purification , Plant Extracts/chemistry , Plant Extracts/pharmacology , Propionates/chemistry , Propionates/isolation & purification , Rats , Sesquiterpenes, Guaiane/chemistry , Sesquiterpenes, Guaiane/isolation & purification , Sesquiterpenes, Guaiane/pharmacologyABSTRACT
Achieving an effective treatment of cancer is difficult, particularly when resistance to conventional chemotherapy is developed. P-glycoprotein (P-gp) activity governs multi-drug resistance (MDR) development in different cancer cell types. Identification of anti-cancer agents with the potential to kill cancer cells and at the same time inhibit MDR is important to intensify the search for novel therapeutic approaches. We examined the effects of sulfinosine (SF), a quite unexplored purine nucleoside analog, in MDR (P-gp over-expressing) non-small cell lung carcinoma (NSCLC) and glioblastoma cell lines (NCI-H460/R and U87-TxR, respectively). SF showed the same efficacy against MDR cancer cell lines and their sensitive counterparts. However, it was non-toxic for normal human keratinocytes (HaCaT). SF induced caspase-dependent apoptotic cell death and autophagy in MDR cancer cells. After SF application, reactive oxygen species (ROS) were generated and glutathione (GSH) concentration was decreased. The expression of key enzyme for GSH synthesis, gamma Glutamyl-cysteine-synthetase (γGCS) was decreased as well as the expression of gst-π mRNA. Consequently, SF significantly decreased the expression of hif-1α, mdr1 and vegf mRNAs even in hypoxic conditions. SF caused the inhibition of P-gp (coded by mdr1) expression and activity. The accumulation of standard chemotherapeutic agent--doxorubicin (DOX) was induced by SF in concentration- and time-dependent manner. The best effect of SF was obtained after 72 h when it attained the effect of known P-gp inhibitors (Dex-verapamil and tariquidar). Accordingly, SF sensitized the resistant cancer cells to DOX in subsequent treatment. Furthermore, SF decreased the experssion of vascular endothelial growth factor (VEGF) on mRNA and protein level and modulated its secretion. In conclusion, the effects on P-gp (implicated in pharmacokinetics and MDR), GSH (implicated in detoxification) and VEGF (implicated in tumor-angiogenesis and progression) qualify SF as multi-potent anti-cancer agent, which use must be considered, in particular for resistant malignancies.
Subject(s)
Carcinoma, Non-Small-Cell Lung/drug therapy , Cell Transformation, Neoplastic/drug effects , Drug Resistance, Multiple/drug effects , Glioblastoma/drug therapy , Purine Nucleosides/administration & dosage , ATP Binding Cassette Transporter, Subfamily B , ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Apoptosis/drug effects , Autophagy/drug effects , Cell Line, Tumor , Doxorubicin/administration & dosage , Drug Resistance, Multiple/genetics , Gene Expression Regulation, Neoplastic/drug effects , Glutamate-Cysteine Ligase/metabolism , Glutathione/biosynthesis , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Reactive Oxygen Species/metabolism , Vascular Endothelial Growth Factor A/geneticsABSTRACT
New polymeric copper(II) complexes with two tridentate ONS thiosemicarbazone ligands containing substituted pyrazolone moiety were synthesized and characterized by means of spectroscopic, electrochemical and crystallographic techniques. While both ligands exist as different tautomers in the solid state and DMSO-d(6) solution, Cu(II) ion coordinates the ligands from the same tautomeric form with square-pyramidal geometry around each Cu atom. In the crystal structures, the copper(II) complex cation forms polymeric chains {[Cu(L)Cl](+)}(n) with a bridging chlorine atom. One of the complexes was found to have a significantly higher cytotoxic potential in comparison with cisplatin in inhibition of several cell lines (HL60, REH, C6, L929 and B16). The results obtained on the basis of flow cytometry indicated that apoptosis could be possible mechanism of cell death.
