betadex and Neoplasm-Metastasis

Cholesterol is abundant in plasma membranes and exhibits a variety of interactions throughout the membrane. Chemical potential accounts for thermodynamic consequences of molecular interactions, and quantifies the effective concentration (i.e., activity) of any substance participating in a process. We have developed, to our knowledge, the first method to measure cholesterol chemical potential in plasma membranes. This was accomplished by complexing methyl-β-cyclodextrin with cholesterol in an aqueous solution and equilibrating it with an organic solvent containing dissolved cholesterol. The chemical potential of cholesterol was thereby equalized in the two phases. Because cholesterol is dilute in the organic phase, here activity and concentration were equivalent. This equivalence allowed the amount of cholesterol bound to methyl-β-cyclodextrin to be converted to cholesterol chemical potential. Our method was used to determine the chemical potential of cholesterol in erythrocytes and in plasma membranes of nucleated cells in culture. For erythrocytes, the chemical potential did not vary when the concentration was below a critical value. Above this value, the chemical potential progressively increased with concentration. We used standard cancer lines to characterize cholesterol chemical potential in plasma membranes of nucleated cells. This chemical potential was significantly greater for highly metastatic breast cancer cells than for nonmetastatic breast cancer cells. Chemical potential depended on density of the cancer cells. A method to alter and fix the cholesterol chemical potential to any value (i.e., a cholesterol chemical potential clamp) was also developed. Cholesterol content did not change when cells were clamped for 24-48 h. It was found that the level of activation of the transcription factor STAT3 increased with increasing cholesterol chemical potential. The cholesterol chemical potential may regulate signaling pathways.

Topics: beta-Cyclodextrins; Breast Neoplasms; Cell Membrane; Cholesterol; Erythrocytes; Female; Humans; Neoplasm Metastasis; Signal Transduction; Thermodynamics; Tumor Cells, Cultured

Cell motility and cell stiffness are closely related to metastatic activity of cancer cells. (-)-Epigallocatechin gallate (EGCG) has been shown to inhibit spontaneous metastasis of melanoma cell line into the lungs of mice, so we studied the effects of EGCG on cell motility, cell stiffness, and expression of vimentin and Slug, which are molecular phenotypes of epithelial-mesenchymal transition (EMT). Treatments of human non-small cell lung cancer cell lines H1299 and Lu99 with 50 and 100 μM EGCG reduced cell motility to 67.5% and 43.7% in H1299, and 71.7% and 31.5% in Lu99, respectively in in vitro wound healing assay. Studies on cell stiffness using atomic force microscope (AFM) revealed that treatment with 50 μM EGCG increased Young's modulus of H1299 from 1.24 to 2.25 kPa and that of Lu99 from 1.29 to 2.28 kPa, showing a 2-fold increase in cell stiffness, i.e. rigid elasticity of cell membrane. Furthermore, treatment with 50 μM EGCG inhibited high expression of vimentin and Slug in the cells at a leading edge of scratch. Methyl-β-cyclodextrin, a reagent to deplete cholesterol in plasma membrane, showed inhibition of EMT phenotypes similar that by EGCG, suggesting that EGCG induces inhibition of EMT phenotypes by alteration of membrane organization.

Topics: Animals; Antineoplastic Agents; beta-Cyclodextrins; Catechin; Cell Line, Tumor; Cell Membrane; Cell Movement; Cholesterol; Elastic Modulus; Epithelial-Mesenchymal Transition; Humans; Mice; Microscopy, Atomic Force; Neoplasm Metastasis; Snail Family Transcription Factors; Transcription Factors; Vimentin

CD44 is a cell surface adhesion molecule for hyaluronan and is implicated in tumor invasion and metastasis. Proteolytic cleavage of CD44 plays a critical role in the migration of tumor cells and is regulated by factors present in the tumor microenvironment, such as hyaluronan oligosaccharides and epidermal growth factor. However, molecular mechanisms underlying the proteolytic cleavage on membranes remain poorly understood. In this study, we demonstrated that cholesterol depletion with methyl-β-cyclodextrin, which disintegrates membrane lipid rafts, enhances CD44 shedding mediated by a disintegrin and metalloproteinase 10 (ADAM10) and that cholesterol depletion disorders CD44 localization to the lipid raft. We also evaluated the effect of long term cholesterol reduction using a statin agent and demonstrated that statin enhances CD44 shedding and suppresses tumor cell migration on a hyaluronan-coated substrate. Our results indicate that membrane lipid organization regulates CD44 shedding and propose a possible molecular mechanism by which cholesterol reduction might be effective for preventing and treating the progression of malignant tumors.

Topics: ADAM Proteins; ADAM10 Protein; Amyloid Precursor Protein Secretases; beta-Cyclodextrins; Cell Line, Tumor; Cell Movement; Cholesterol; Epidermal Growth Factor; Glioma; Humans; Hyaluronan Receptors; Hyaluronic Acid; Membrane Microdomains; Membrane Proteins; Neoplasm Metastasis; Neoplasm Proteins

Earlier reports indicated that the conjugates (PEI(600)-CD, PC) of β-cyclodextrin and low-molecular-weight polyethylenimine (PEI, M(w) 600) can be used as efficient gene carriers in glioma cancer therapy. Incorporating anticancer drugs onto PC conjugates may endow them with new and interesting properties for great applications. In this work, FU-PEI(600)-CD (FPC) conjugates comprising PC and 5-fluoro-2'-deoxyuridine (FdUrd) were prepared as new bifunctional anticancer prodrugs with improved therapeutic effects, as well as good gene transfer efficiency. In comparison with free FdUrd, FPC could inhibit proliferation and enhance cytotoxicity on glioma cells. The results of hematoxylin and eosin (HE) staining indicated that C6 cells treated with FPC shrunk more seriously. Unlike FdUrd, cell cycle analysis indicated that C6 cells were primarily arrested in the G1 phase in the presence of FPC. Cellular uptake of FPC in C6 cells was about 10 times higher than that of FdUrd. In addition, the in vitro and in vivo gene transfection indicated that FPC still exhibited good gene expression efficiency. With the ability to deliver drugs and transfer genes, such bifunctional FPC conjugates may have great potential applications in combination therapy of cancers.

Topics: Animals; Antineoplastic Agents; Apoptosis; beta-Cyclodextrins; Cell Cycle; Cell Line, Tumor; Cell Proliferation; DNA; Drug Carriers; Female; Floxuridine; Mice; Molecular Weight; Neoplasm Metastasis; Polyethyleneimine; Transfection; Uridine; Wound Healing

Polyelectrolyte multilayers (PEM) are well established nanoarchitectures with numerous potential applications, in particular as biomaterial coatings. They may exhibit specific biological properties in terms of controlled cell activation or local drug delivery. Here, in a new approach for bone metastasis prevention, we employed poly-l-lysine covalently grafted with beta-cyclodextrin as a polycationic vector (PLL-CD) for the antitumor bisphosphonate drug risedronate (RIS). Molar ratio for maximum loading of the PLL-CD vector with RIS was determined by Raman microspectroscopy. The efficacy of RIS at inhibiting cancer cell invasion in vitro was strongly enhanced upon complexation, whatever PLL-CD:RIS complexes were in solution or embedded into PEM nanoarchitectures. Complexes in solution also clearly prevented cancer-induced bone metastasis in animals. Incorporation of the complexes into PEM nanoarchitectures covering bone implants appears of interest for in situ prevention of bone metastasis after ablation.

Topics: Animals; Antinematodal Agents; beta-Cyclodextrins; Bone Neoplasms; Drug Delivery Systems; Etidronic Acid; Female; Mice; Mice, Inbred BALB C; Nanostructures; Neoplasm Metastasis; Risedronic Acid; Spectrum Analysis, Raman

The effect of beta-cyclodextrin-benzaldehyde (CDBA) on experimental pulmonary metastasis in C3H/He mice was examined. In an in vitro assay, the growth of RCT(+) cells was inhibited by 1200 micrograms/ml CDBA using unrenewed media, and by 600 micrograms/ml CDBA in that using daily renewed media. When mice were treated daily with CDBA, 3 weeks later the number of lung nodules developing after i.v. injection of 1 X 10(6) RCT(+) cells was significantly decreased in a dose-dependent manner, i.e., 73.8%, 85.6%, and 95.7% inhibition was observed following 0.5, 5, and 25 mg CDBA/mouse per day p.o. administration, respectively. The same mice showed almost as much natural killer (NK) activity as normal mice. Therefore, experiments were designed to evaluate the effect of CDBA on the NK activity of tumor-free mice whose immunity had been suppressed by 5-fluorouracil (5FU). Injections of 5FU only suppressed this activity to about 50% of normal mice, but the combined treatment with CDBA negated the suppressive effect of 5FU on NK activity. The results suggested that the inhibition of experimental pulmonary metastasis might be induced by the possible combined effects of CDBA; that is, the direct inhibition of tumors and the augmentation of NK cell activity.

Topics: Animals; Benzaldehydes; beta-Cyclodextrins; Cyclodextrins; Cytotoxicity, Immunologic; Dextrins; Fluorouracil; Immunosuppression Therapy; Killer Cells, Natural; Lung Neoplasms; Male; Mice; Mice, Inbred C3H; Neoplasm Metastasis; Neoplasms, Experimental; Starch