Background: The aim of this study was to investigate the effects of poly-lactic-co-glycolic acid (PLGA) nanotopographies with alginate or chitosan protein preadsorption o... More
Background: The aim of this study was to investigate the effects of poly-lactic-co-glycolic acid (PLGA) nanotopographies with alginate or chitosan protein preadsorption on the functioning of healthy and cancerous lung and breast cells, including adhesion, proliferation, apoptosis, and release of vascular endothelial growth factor (VEGF), which promotes tumor angiogenesis and secretion. Methods: We used a well established cast-mold technique to create nanoscale surface features on PLGA. Some of the nanomodified PLGA films were then exposed to alginate and chitosan. Surface roughness and the presence of protein was confirmed by atomic force microscopy. Surface energy was quantified by contact angle measurement. Results: Nanostructured PLGA surfaces with 23 nm features decreased synthesis of VEGF in both lung and breast cancer cells compared with conventional PLGA. Preadsorbing alginate further decreased cancer cell function, with nanostructured PLGA preadsorbed with alginate achieving the greatest decrease in synthesis of VEGF in both lung and breast cancer cells. In contrast, compared with nonmodified smooth PLGA, healthy cell functions were either not altered (ie, breast) or were enhanced (ie, lung) by use of nanostructured features and alginate or chitosan protein preadsorption. Conclusion: Using this technique, we developed surface nanometric roughness and modification of surface chemistry that could selectively decrease breast and lung cancer cell functioning without the need for chemotherapeutics. This technique requires further study in a wide range of anticancer and regenerative medicine applications. Keywords: alginate; breast; cancer; chitosan; lung; nanotechnology. Less
Targeted delivery of drugs to tumors represents a significant advance in cancer diagnosis and therapy. Therefore, development of novel tumor-specific ligands or pharmaceu... More
Targeted delivery of drugs to tumors represents a significant advance in cancer diagnosis and therapy. Therefore, development of novel tumor-specific ligands or pharmaceutical nanocarriers is highly desirable. In this study, we utilized phage display to identify a new targeting peptide, SP90, which specifically binds to breast cancer cells, and recognizes tumor tissues from breast cancer patients. We used confocal and electron microscopy to reveal that conjugation of SP90 with liposomes enables efficient delivery of drugs into cancer cells through endocytosis. Furthermore, in vivo fluorescent imaging demonstrated that SP90-conjugated quantum dots possess tumor-targeting properties. In tumor xenograft and orthotopic models, SP90-conjugated liposomal doxorubicin was found to improve the therapeutic index of the chemotherapeutic drug by selectively increasing its accumulation in tumors. We conclude that the targeting peptide SP90 has significant potential in improving the clinical benefits of chemotherapy in the treatment and the diagnosis of breast cancer. Less
The neat and lyotropic phase behavior of eight new ethylene oxide amphiphiles (EO = 1-8) with a hexahydrofarnesyl chain (3,7,11-trimethyldodecyl) and narrow polydispersit... More
The neat and lyotropic phase behavior of eight new ethylene oxide amphiphiles (EO = 1-8) with a hexahydrofarnesyl chain (3,7,11-trimethyldodecyl) and narrow polydispersity (>98.5% purity) is reported. Below five EO units the behavior of the neat surfactants show only a glass transition, Tg ∼ -90 °C. Above four EO units, crystallization (Tcrys) and crystal-isotropic liquid (Tm) transitions are also observed that increase with degree of ethoxylation of the surfactant headgroup. The lyotropic liquid crystalline phase behavior spans a complex spectrum of surfactant-water interfacial curvatures. Specifically, inverse phases are present below ambient temperatures for EO < 4, with HFarn(EO)2 exhibiting an inverse hexagonal (H(II)) phase stable to dilution. The phase diagram of HFarn(EO)3 displays both the gyroid (Ia3d) and double diamond (Pn3m) inverse bicontinuous cubic phases, with the latter being thermodynamically stable in excess water within the physiological regime. There is a strong preference for planar bilayer structures at intermediate headgroup ethoxylation, with the crossover to normal phases occurring at HFarn(EO)(7-8) which exhibits normal hexagonal (H(I)) and cubic (Q(I)) phases at ambient temperatures. The toxicity of colloidal dispersions of these EO amphiphiles was assayed against normal breast epithelial (HMEpiC) and breast cancer (MCF7) cell lines. The IC50 of the EO amphiphiles was similar in both cell lines with moderate toxicity ranging from ca. <5 to 140 μM in an in vitro cell viability assay. Observations are qualitatively rationalized in terms of the molecular geometry of the surfactant. The physicochemical behavior of the HFarnesyl ethylene oxide amphiphiles is compared to other ethylene oxide surfactants. Less
An amphiphile prodrug, 5'-deoxy-5-fluoro-N(4)-(palmityloxycarbonyl) cytidine or 5'-deoxy-5-fluoro-N(4)-(hexadecanaloxycarbonyl) cytidine (5-FCPal), consisting of the same... More
An amphiphile prodrug, 5'-deoxy-5-fluoro-N(4)-(palmityloxycarbonyl) cytidine or 5'-deoxy-5-fluoro-N(4)-(hexadecanaloxycarbonyl) cytidine (5-FCPal), consisting of the same head group as the commercially available chemotherapeutic agent Capecitabine, linked to a palmityl hydrocarbon chain via a carbamate bond is reported. Thermal analysis of this prodrug indicates that it melts at ∼115 °C followed quickly by degradation beginning at ∼120 °C. The neat solid 5-FCPal amphiphile acquires a lamellar crystalline arrangement with a d-spacing of 28.6±0.3 Å, indicating interdigitation of the hydrocarbon chains. Under aqueous conditions, solid 5-FCPal is non-swelling and no lyotropic liquid crystalline phase formation is observed. In order to assess the in vitro toxicity and in vivo efficacy in colloidal form, solid lipid nanoparticles (SLNs) with an average size of ∼700 nm were produced via high pressure homogenization. The in vitro toxicity of the 5-FCPal SLNs against several different cancer and normal cell types was assessed over a 48 h period, and IC(50) values were comparable to those observed for Capecitabine. The in vivo efficacy of the 5-FCPal SLNs was then assessed against the highly aggressive mouse 4T1 breast cancer model. To do so, the prodrug SLNs were administered orally at 3 different dosages (0.1, 0.25, 0.5 mmol/mouse/day) and compared to Capecitabine delivered at the same dosages. After 21 days of receiving the treatments, the 0.5 mmol dose of 5-FCPal exhibited the smallest average tumour volume. Since 5-FCPal is activated in a similar manner to Capecitabine via a 3 step enzymatic pathway with the final step occurring preferentially at the tumour site, formulation of the prodrug into SLNs combines the advantage of selective, localized activation with the sustained release properties of nanostructured amphiphile self-assembly and multiple payload materials thereby potentially creating a more effective anticancer agent. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved. Less
Mutations in growth signaling pathways extend life span, as well as protect against age-dependent DNA damage in yeast and decrease insulin resistance and cancer in mice. ... More
Mutations in growth signaling pathways extend life span, as well as protect against age-dependent DNA damage in yeast and decrease insulin resistance and cancer in mice. To test their effect in humans, we monitored for 22 years Ecuadorian individuals who carry mutations in the growth hormone receptor (GHR) gene that lead to severe GHR and IGF-1 (insulin-like growth factor-1) deficiencies. We combined this information with surveys to identify the cause and age of death for individuals in this community who died before this period. The individuals with GHR deficiency exhibited only one nonlethal malignancy and no cases of diabetes, in contrast to a prevalence of 17% for cancer and 5% for diabetes in control subjects. A possible explanation for the very low incidence of cancer was suggested by in vitro studies: Serum from subjects with GHR deficiency reduced DNA breaks but increased apoptosis in human mammary epithelial cells treated with hydrogen peroxide. Serum from GHR-deficient subjects also caused reduced expression of RAS, PKA (protein kinase A), and TOR (target of rapamycin) and up-regulation of SOD2 (superoxide dismutase 2) in treated cells, changes that promote cellular protection and life-span extension in model organisms. We also observed reduced insulin concentrations (1.4 μU/ml versus 4.4 μU/ml in unaffected relatives) and a very low HOMA-IR (homeostatic model assessment-insulin resistance) index (0.34 versus 0.96 in unaffected relatives) in individuals with GHR deficiency, indicating higher insulin sensitivity, which could explain the absence of diabetes in these subjects. These results provide evidence for a role of evolutionarily conserved pathways in the control of aging and disease burden in humans. Less
The n-acylethanolamides (NAEs) are a family of naturally occurring monoethanolamide containing lipids that display a variety of interesting biological properties. In this... More
The n-acylethanolamides (NAEs) are a family of naturally occurring monoethanolamide containing lipids that display a variety of interesting biological properties. In this study, some physicochemical properties of a series of saturated monoethanolamide lipids with increasing hydrocarbon chain length (lauroyl, myristoyl, palmitoyl, and stearoyl) have been investigated. Temperature induced phase transitions for these NAEs indicate that both the monoethanolamide headgroups and the unsaturated hydrophobic tails play a role in the melting behavior of these lipids. All four lipids examined demonstrate the presence of at least three different polymorphic crystal forms. Transitions in crystal structure can be induced via heating and visualized with polarized optical microscopy. At room and physiological temperature, the four NAEs are solid lamellar crystalline materials. All four molecules form lyotropic liquid crystalline phases in water, albeit at relatively high temperatures, including the lamellar liquid crystalline phase and at least two isotropic phases. Lamellar crystalline palmitoyl monoethanolamide was dispersed as solid lipid nanoparticles (SLNs). The cytotoxicity of these SLNs toward human mammary epithelial cells (HMEpiC) and the MCF7 breast cancer cell line was assessed at physiological temperature. The palmitoyl monoethanolamide SLNs showed little to no toxicity to the HMEpiC even at a concentration of 30 microM. At concentrations above 3 microM, the HMEpiC population was reduced by less than 15%, while the MCF7 population was reduced by approximately 20-30%. The endogenous nature and natural medicinal properties make this series of lipids ideal candidates for further investigation as solid lipid nanoparticle drug delivery systems. Less
Before metastasis, certain organs have already been influenced by primary tumors. However, the exact alterations and regulatory mechanisms of the premetastatic organs rem... More
Before metastasis, certain organs have already been influenced by primary tumors. However, the exact alterations and regulatory mechanisms of the premetastatic organs remain poorly understood. Here, we report that, in the premetastatic stage, angiopoietin 2 (Angpt2), matrix metalloproteinase (MMP) 3, and MMP10 are up-regulated in the lung by primary B16/F10 tumor, which leads to the increased permeability of pulmonary vasculatures and extravasation of circulating tumor cells. Subsequent studies show that Angpt2, MMP3, and MMP10 have a synergistic effect on disrupting vascular integrity in both in vitro and in vivo models. Lentivirus-based in vivo RNA interference of Angpt2, MMP3, and MMP10 attenuates the pulmonary vascular permeability and suppresses the infiltration of myeloid cells in the premetastatic lung. Moreover, knocking down these factors significantly inhibits the spontaneous lung metastasis in the model by orthotopic implantation of MDA-MB-231-Luc-D3H1 cells in nude mice. Further investigations reveal that the malignancy of tumor cells is positively correlated with their capabilities to induce the expression of Angpt2, MMP3, and MMP10. Luciferase reporter assay and chromatin immunoprecipitation assay also suggest that transforming growth factor-beta1 and tumor necrosis factor-alpha signaling are involved in the regulation of these premetastatic factors. Our study shows that pulmonary vascular destabilization in the premetastatic phase promotes the extravasation of tumor cells and facilitates lung metastasis, which may provide potential targets for clinical prevention of metastasis. Less
