Journal Article

Animals; Bioware; Breast Neoplasms; Cell Line, Tumor; Fluorescence; Fluorescent Dyes; Humans; Liposomes; Magnetic Resonance Imaging; Magnetics; MDA-MB-231-D3H1 cells; Mice; Mice, Inbred Strains; Microscopy, Confocal; Molecular Probes; Optics and Photonics; Transferrin; Xenograft Model Antitumor Assays

A dual probe with fluorescent and magnetic reporter groups was constructed by linkage of the near-infrared (NIR) fluorescent transferrin conjugate (Tf(NIR)) on the surface of contrast agent-encapsulated cationic liposome (Lip-CA). This probe was used for magnetic resonance imaging (MRI) and optical imaging of MDA-MB-231-luc breast cancer cells grown as a monolayer in vitro and as solid tumor xenografts in nude mice. Confocal microscopy, optical imaging, and MRI showed a dramatic increase of in vitro cellular uptake of the fluorescent and magnetic reporter groups from the probe compared with the uptake of contrast agent or Lip-CA alone. Pretreatment with transferrin (Tf) blocked uptake of the probe reporters, indicating the importance and specificity of the Tf moiety for targeting. Intravenous administration of the dual probe to nude mice significantly enhanced the tumor contrast in MRI, and preferential accumulation of the fluorescent signal was clearly seen in NIR-based optical images. More interestingly, the contrast enhancement in MRI showed a heterogeneous pattern within tumors, which reflected the tumor's morphologic heterogeneity. These results indicate that the newly developed dual probe enhances the tumor image contrast and is superior to contrast agent alone for identifying the tumor pathologic features on the basis of MRI but also is suitable for NIR-based optical imaging.

Journal Article

A549-luc-C8 cells; Bioware; Cell Line, Tumor; Cell Nucleus; Cell Separation; Electrophoresis; Humans; Microfluidic Analytical Techniques

This study reports a new biochip capable of cell separation and nucleus collection utilizing dielectrophoresis (DEP) forces in a microfluidic system comprising of micropumps and microvalves, operating in an automatic format. DEP forces operated at a low voltage (15 Vp-p) and at a specific frequency (16 MHz) can be used to separate cells in a continuous flow, which can be subsequently collected. In order to transport the cell samples continuously, a serpentine-shape (S-shape) pneumatic micropump device was constructed onto the chip device to drive the samples flow through the microchannel, which was activated by the pressurized air injection. The mixed cell samples were first injected into an inlet reservoir and driven through the DEP electrodes to separate specific samples. Finally, separated cell samples were collected individually in two outlet reservoirs controlled by microvalves. With the same operation principle, the nucleus of the specific cells can be collected after the cell lysis procedure. The pumping rate of the micropump was measured to be 39.8 microl/min at a pressure of 25 psi and a driving frequency of 28 Hz. For the cell separation process, the initial flow rate was 3 microl/min provided by the micropump. A throughput of 240 cells/min can be obtained by using the developed device. The DEP electrode array, microchannels, micropumps and microvalves are integrated on a microfluidic chip using micro-electro-mechanical-systems (MEMS) technology to perform several crucial procedures including cell transportation, separation and collection. The dimensions of the integrated chip device were measured to be 6x7 cm. By integrating an S-shape pump and pneumatic microvalves, different cells are automatically transported in the microchannel, separated by the DEP forces, and finally sorted to specific chambers. Experimental data show that viable and non-viable cells (human lung cancer cell, A549-luc-C8) can be successfully separated and collected using the developed microfluidic platform. The separation accuracy, depending on the DEP operating mode used, of the viable and non-viable cells are measured to be 84 and 81%, respectively. In addition, after cell lysis, the nucleus can be also collected using a similar scheme. The developed automatic microfluidic platform is useful for extracting nuclear proteins from living cells. The extracted nuclear proteins are ready for nuclear binding assays or the study of nuclear proteins.

Journal Article

Animals; Anthrax; Bacillus anthracis; Bioware; Disease Models, Animal; Gastrointestinal Diseases; Inhalation Exposure; Luciferases; Luminescence; Luminescent Measurements; Lymph Nodes; Mice; Mice, Inbred BALB C; Nasal Cavity; Organisms, Genetically Modified; Peyer's Patches; Pharynx; pXen-5; Skin; Spores, Bacterial

Bacillus anthracis causes three forms of anthrax: inhalational, gastrointestinal, and cutaneous. Anthrax is characterized by both toxemia, which is caused by secretion of immunomodulating toxins (lethal toxin and edema toxin), and septicemia, which is associated with bacterial encapsulation. Here we report that, contrary to the current view of B. anthracis pathogenesis, B. anthracis spores germinate and establish infections at the initial site of inoculation in both inhalational and cutaneous infections without needing to be transported to draining lymph nodes, and that inhaled spores establish initial infection in nasal-associated lymphoid tissues. Furthermore, we found that Peyer's patches in the mouse intestine are the primary site of bacterial growth after intragastric inoculation, thus establishing an animal model of gastrointestinal anthrax. All routes of infection progressed to the draining lymph nodes, spleen, lungs, and ultimately the blood. These discoveries were made possible through the development of a novel dynamic mouse model of B. anthracis infection using bioluminescent non-toxinogenic capsulated bacteria that can be visualized within the mouse in real-time, and demonstrate the value of in vivo imaging in the analysis of B. anthracis infection. Our data imply that previously unrecognized portals of bacterial entry demand more intensive investigation, and will significantly transform the current perception of inhalational, gastrointestinal, and cutaneous B. anthracis pathogenesis.

Journal Article

Animals; Antineoplastic Agents; Bioware; Cell Line, Tumor; Drug Carriers; Drug Delivery Systems; Female; Hela Cells; HeLa-luc; Humans; Mice; Mice, SCID; Micelles; Neoplasms; Organoplatinum Compounds; Platinum; Polymers; Xenograft Model Antitumor Assays

Polymeric micelles are promising nanocarriers, which might enhance the efficacy of antitumor drugs. Herein, polymeric micelles incorporating dichloro(1,2-diamino-cyclohexane)platinum(II) (DACHPt), the oxaliplatin parent complex, were prepared through the polymer-metal complex formation of DACHPt with poly(ethylene glycol)-b-poly(glutamic acid) [PEG-b-P(Glu)] block copolymer having different lengths of the poly(glutamic acid) block [p(Glu): 20, 40, and 70 U]. The resulting micelles were studied with the aim of optimizing the system's biological performance. DACHPt-loaded micelles (DACHPt/m) were approximately 40 nm in diameter and had a narrow size distribution. In vivo biodistribution and antitumor activity experiments (CDF1 mice bearing the murine colon adenocarcinoma C-26 inoculated subcutaneously) showed 20-fold greater accumulation of DACHPt/m at the tumor site than free oxaliplatin to achieve substantially higher antitumor efficacy. Moreover, the micelles prepared from PEG-b-P(Glu) with 20 U of P(Glu) exhibited the lowest non-specific accumulation in the liver and spleen to critically reduce non-specific accumulation, resulting in higher specificity to solid tumors. The antitumor effect of DACHPt/m was also evaluated on multiple metastases generated from intraperitoneally injected bioluminescent HeLa (HeLa-Luc) cells. The in vivo bioluminescent data indicated that DACHPt/m decreased the signal 10-to 50-fold compared to the control indicating a very strong antitumor activity. These results suggest that DACHPt/m could be an outstanding drug delivery system for oxaliplatin in the treatment of solid tumors.

Journal Article

Acetyl-CoA Carboxylase; Apoptosis; Autophagy; Bioware; Cell Death; Cell Proliferation; Drug Evaluation, Preclinical; Fatty Acids; Humans; Macrolides; Male; Neoplasms; Palmitic Acid; PC-3M-luc; Phospholipids; Prostatic Neoplasms; Tumor Cells, Cultured

Development and progression of cancer is accompanied by marked changes in the expression and activity of enzymes involved in the cellular homeostasis of fatty acids. One class of enzymes that play a particularly important role in this process are the acetyl-CoA carboxylases (ACC). ACCs produce malonyl-CoA, an intermediate metabolite that functions as substrate for fatty acid synthesis and as negative regulator of fatty acid oxidation. Here, using the potent ACC inhibitor soraphen A, a macrocyclic polyketide from myxobacteria, we show that ACC activity in cancer cells is essential for proliferation and survival. Even at nanomolar concentrations, soraphen A can block fatty acid synthesis and stimulate fatty acid oxidation in LNCaP and PC-3M prostate cancer cells. As a result, the phospholipid content of cancer cells decreased, and cells stopped proliferating and ultimately died. LNCaP cells predominantly died through apoptosis, whereas PC-3M cells showed signs of autophagy. Supplementation of the culture medium with exogenous palmitic acid completely abolished the effects of soraphen A and rescued the cells from cell death. Interestingly, when added to cultures of premalignant BPH-1 cells, soraphen A only slightly affected cell proliferation and did not induce cell death. Together, these findings indicate that cancer cells have become dependent on ACC activity to provide the cell with a sufficient supply of fatty acids to permit proliferation and survival, introducing the concept of using small-molecule ACC inhibitors as therapeutic agents for cancer.