betadex and helenalin

Nowadays, the encapsulation of cytotoxic chemotherapeutic agents is attracting interest as a method for drug delivery. We hypothesized that the efficiency of helenalin might be maximized by encapsulation in β-cyclodextrin nanoparticles. Helenalin, with a hydrophobic structure obtained from flowers of Arnica chamissonis and Arnica Montana, has anti-cancer and anti-inflammatory activity but low water solubility and bioavailability. β-Cyclodextrin (β-CD) is a cyclic oligosaccharide comprising seven D-glucopyranoside units, linked through 1,4-glycosidic bonds.. To test our hypothesis, we prepared β-cyclodextrin- helenalin complexes to determine their inhibitory effects on telomerase gene expression by real-time polymerase chain reaction (q-PCR) and cytotoxic effects by colorimetric cell viability (MTT) assay.. MTT assay showed that not only β-cyclodextrin has no cytotoxic effect on its own but also it demonstrated that β-cyclodextrin- helenalin complexes inhibited the growth of the T47D breast cancer cell line in a time and dose-dependent manner. Our q-PCR results showed that the expression of telomerase gene was effectively reduced as the concentration of β-cyclodextrin-helenalin complexes increased.. β-Cyclodextrin-helenalin complexes exerted cytotoxic effects on T47D cells through down-regulation of telomerase expression and by enhancing Helenalin uptake by cells. Therefore, β-cyclodextrin could be superior carrier for this kind of hydrophobic agent.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; beta-Cyclodextrins; Breast Neoplasms; Cell Proliferation; Female; Humans; Nanoparticles; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sequestering Agents; Sesquiterpenes; Sesquiterpenes, Guaiane; Spectroscopy, Fourier Transform Infrared; Telomerase; Tumor Cells, Cultured

Tumor necrosis factor alpha (TNFalpha) is involved in the pathogenesis of many inflammatory skin diseases. Epidermal keratinocytes produce and respond to TNFalpha via the cognate type 1 receptor (TNFR1). Little is known about regulation of TNFalpha signalling in this cell type. In this study, we report that in keratinocytes TNFalpha upregulates its own mRNA synthesis in an autocrine manner. This response peaks at approximately 1h of stimulation with TNFalpha but sustained elevated levels of TNFalpha mRNA are observed for up to 24h after stimulation and are dependent on the presence of the soluble cytokine. This autocrine response is mediated by the signalling cascade comprising TNFR1, atypical protein kinase C (aPKC) species and the transcription factor NF-kappaB, but is not dependent on the integrity of cholesterol-enriched membrane microdomains (lipid rafts). TNFalpha-stimulated keratinocytes produced the membrane-bound form of TNFalpha. It is conceivable that the described autocrine signalling loop contributes to the proinflammatory TNFalpha effect in the skin. The discovery of the crucial roles of aPKC and NF-kappaB might have consequences for the development of more selective anti-TNFalpha therapies for inflammatory skin diseases.

Topics: Antibodies, Monoclonal; Autocrine Communication; beta-Cyclodextrins; Carbazoles; Cell Line; Cholesterol; Dose-Response Relationship, Drug; Humans; Indoles; Infliximab; Keratinocytes; Membrane Microdomains; NF-kappa B; Protein Kinase C; Receptors, Tumor Necrosis Factor, Type I; RNA, Messenger; Sesquiterpenes; Sesquiterpenes, Guaiane; Signal Transduction; Tumor Necrosis Factor-alpha