Journal Article

Bioware; Imaging systems; PC-3M-luc; Spectroscopy, fluorescence and luminescence

N/A

Journal Article

Antibiotics -- Therapeutic use; Bacteriocins; Bioware; Dissertations -- Microbiology; Drug resistance in microorganisms; Nisin; Respiratory infections -- Treatment; Skin -- Infections -- Treatment; Staphylococcus aureus; Theses -- Microbiology; Xen29

Multidrug resistant strains of Staphylococcus aureus is presenting an increasing threat, especially immune compromised individuals. Many of these strains have developed resistance to newly approved drugs such as quinupristin-dalfopristin, linezolid and daptomycin. The search for alternative treatment, including bacteriocins (ribosomally synthesized antimicrobial peptides) of lactic acid bacteria is increasing . Lactococcus lactis subsp. lactis F10, isolated from freshwater catfish, produced a new nisin variant active against clinical strains of S. aureus. The operon encoding nisin F is located on a plasmid and the structural gene has been sequenced. The lantibiotic is closely related to nisin Z, except at position 30 where valine replaced isoleucine. The antimicrobial activity of nisin F against S. aureus was tested in the respiratory tract of Wistar rats. Non-immunosuppressed and immunosuppressed rats were intranasally infected with S. aureus K and then treated with either nisin F or sterile physiological saline. Nisin F protected immunosuppressed rats against S. aureus, as symptoms of an infection were only detected in the trachea and lungs of immunosuppressed rats treated with saline. The safety of intranasally administered nisin F was also evaluated and proved to have no adverse side effects. The potential of nisin F as an antimicrobial agent to treat subcutaneous skin infections was evaluated by infecting C57BL/6 mice with a bioluminescent strain of S. aureus (Xen 36). Immunosuppressed mice were treated with either nisin F or sterile physiological saline 24 h and 48 h after infection with subcutaneously injected S. aureus Xen 36. Histology and bioluminescence flux measurements revealed that nisin F was ineffective in the treatment of deep dermal staphylococcal infections. Non-infected and infected mice treated with nisin F had an influx of polymorphonuclear cells in the deep stroma of the skin tissue. This suggested that nisin F, when injected subcutaneously, may have modulated the immune system. Nisin F proved an effective antimicrobial agent against S. aureus-related infections in the respiratory tract, but not against subcutaneous infections. The outcome of nisin F treatment thus depends on the route of administration and site of infection.

Journal Article

Bioware; PC-3M-luc; hVEGF-luc-PC3M

Background: Preclinical cancer studies increasingly utilize non-invasive imaging modalities. In the current study we have monitored tumor growth and vascular changes using two in vivo imaging tools: surface bioluminescence (BLI) and ultrasound biomicroscopy (UBM). BLI permits visualization of tumor location in the context of the whole body, including metastases localization. UBM imaging then permits high resolution 3D volumetric tumor measurements as well as blood flow estimates down to 200 microns/s. Measurements obtained from these complementary modalities were analyzed and compared to conventional, biochemical markers. Methods: Human prostate cancer cells expressing Firefly Luciferase constitutively (PC-3M-luc-C6) or under the control of hVEGF promoter (hVEGF-luc/PC3M) were implanted into male nude mice via an intradermal or subcutaneous injection. Tumor-bearing mice were subsequently imaged every week for nine weeks starting at week 2, by UBM to measure tumor burden using 3D volumetric analysis, or to estimate blood flow using speckle-variance flow processing. Surface bioluminescence was also acquired 10 minutes post i.p. injection of D-luciferin. In a longitudinal drug intervention study anti-hVEGF antibody (Bevacizumab, 200 ug) was injected i.p. into nude mice with subcutaneous xenografts of PC-3M-luc-C6 or hVEGF-luc/PC-3M twice per week for three weeks, starting at 14 days post-xenograft. UBM and surface BLI imaging were conducted every week. In order to study the correlation between VEGF expression in hVEGF-luc/PC3M xenografts (estimated by BLI) to tumor hypoxia level, mice were injected with pimonidazole hydrochloride (60 mg/kg i.v.) after three weeks of treatment and tumors were harvested for immunostaining analysis. Results: Surface BLI outputs (photons/s) from subcutaneous PC-3M-luc-C6 xenografts were highly correlated to tumor volumes measured using 3D UBM for small tumors (<100 mm3, r=0.92, n=8), yet poorly correlated to tumors of large size (>100 mm3, r=0.079, n=8). BLI signals in subcutaneous hVEGF-luc/PC3M xenografts showed an inverse trend to tumor blood flow. PC-3M-luc-C6 tumors treated with Bevacizumab showed growth inhibition by day 28 as demonstrated by 3D UBM (control vs treated = 67.27 vs 48.54 mm3). Moreover, control xenografts showed increased average BLI output over time, whereas treated tumors showed variation in BLI output. Necrosis, hypoxia and blood flow estimates were also investigated. Conclusions: Surface bioluminescence imaging demonstrated high correlations to accurate 3D UBM volumetric measurements of small tumor volumes, suggesting its usefulness in tracking early tumor growth quantitatively in drug intervention studies. A complementary imaging modality, like ultrasound biomicroscopy, is recommended to monitor tumor burden in advanced stages.

Journal Article

Bioware; MCF-7-luc-F5 cells

A clonal human tumor cell line expressing firefly luciferase, MCF-7-luc-F5, was developed from parental MCF-7 breast carcinoma cells and characterized for bioluminescence in vitro and in vivo. As few as twenty cells were detectable in vitro and average bioluminescence measured approximately 680 photons/sec/cell. Tumorigenesis of MCF-7-luc-F5 cells was assessed with and without estrogen supplement in vivo following injection of cells into the mammary fat pad of nude-beige mice. Continuous tumor growth was observed by weekly bioluminescent imaging in mice receiving a slow release (60 day) estrogen pellet implant (0.36 mg/pellet), while no tumor growth occurred in mice without estrogen supplement. Caliper measurements of tumor volume indicated similar results. A kinetic analysis of luciferase activity in vivo demonstrated that peak signals were evident approximately 12-15 minutes after injection of luciferin substrate and were maintained at a relatively stable level for at least another 20-25 minutes. Spontaneous metastasis from the primary mammary fat pad tumor to thoracic and axillary regions was observed in vivo in 50% of the animals. Subsequent ex vivo images and histology identified metastatic sites in lung, rib, or lymph nodes depending on the mouse. Standard drug treatment on primary and secondary tumor growth was also monitored by bioluminescent imaging.

Journal Article

Annexin Vivo, Annexin-Vivo, IVIS, Animals; Antineoplastic Agents/*administration & dosage; Apoptosis; Cell Line, Tumor; Doxorubicin/*administration & dosage; Drug Carriers; Drug Delivery Systems; Female; Glioblastoma/drug therapy; Gold/chemistry; Humans; Liposomes/*chemistry; Metal Nanoparticles/chemistry; Mice; Mice, Nude; Nanostructures/chemistry; Neoplasms/*drug therapy; Polyethylene Glycols/chemistry

Delivery of chemotherapeutic agents after encapsulation in nanocarriers such as liposomes diminishes side-effects, as PEGylated nanocarrier pharmacokinetics decrease dosing to healthy tissues and accumulate in tumors due to the enhanced permeability and retention effect. Once in the tumor, however, dosing of the chemotherapeutic to tumor cells is limited potentially by the rate of release from the carriers and the size-constrained, poor diffusivity of nanocarriers in tumor interstitium. Here, we report the design and fabrication of a thermosensitive liposomal nanocarrier that maintains its encapsulation stability with a high concentration of doxorubicin payload, thereby minimizing “leak” and attendant toxicity. When used synergistically with PEGylated gold nanorods and near-infrared stimulation, remote triggered release of doxorubicin from thermosensitive liposomes was achieved in a mouse tumor model of human glioblastoma (U87), resulting in a significant increase in efficacy when compared to nontriggered or nonthermosensitive PEGylated liposomes. This enhancement in efficacy is attributed to increase in tumor-site apoptosis, as was evident from noninvasive apoptosis imaging using Annexin-Vivo 750 probe. This strategy affords remotely triggered control of tumor dosing of nanocarrier-encapsulated doxorubicin without sacrificing the ability to differentially dose drugs to tumors via the enhanced permeation and retention effect.