Citation Details

Journal Article

Animals; Anti-Infective Agents; Bacterial Adhesion; Biofilms; Bioware; Chromosomes, Bacterial; Colony Count, Microbial; Disease Models, Animal; Female; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Prostheses and Implants; pXen-5; Soft Tissue Infections; Staphylococcal Infections; Staphylococcus aureus; Xen29

Infection is the main cause of biomaterials-related failure. A simple technique to test in-vivo new antimicrobial and/or nonadhesive implant coatings is unavailable. Current in vitro methods for studying bacterial adhesion and growth on biomaterial surfaces lack the influence of the host immune system. Most in vivo methods to study biomaterials-related infections routinely involve implant-removal, preventing comprehensive longitudinal monitoring. In vivo imaging circumvents these drawbacks and is based on the use of noninvasive optical imaging of bioluminescent bacteria. Staphylococcus aureus Xen29 is genetically modified to be stably bioluminescent, by the introduction of a modified full lux operon onto its chromosome. Surgical meshes with adhering S. aureus Xen29 were implanted in mice and bacterial growth and spread into the surrounding tissue was monitored longitudinally from bioluminescence with a highly sensitive CCD camera. Distinct spatiotemporal bioluminescence patterns, extending beyond the mesh area into surrounding tissues were observed. After 10 days, the number of living organisms isolated from explanted meshes was found to correlate with bioluminescence prior to sacrifice of the animals. Therefore, it is concluded that in vivo imaging using bioluminescent bacteria is ideally suited to study antimicrobial coatings taking into account the host immune system. In addition, longitudinal monitoring of infection in one animal will significantly reduce the number of experiments and animals.

Journal Article

Animals; Antibiotics, Antitubercular; Biofilms; Bioware; Colony Count, Microbial; Diagnostic Imaging; DNA-Directed RNA Polymerases; Luminescent Measurements; Mice; Rifampin; Staphylococcal Infections; Staphylococcus aureus; Xen29

Eradication of Staphylococcus aureus biofilms after rifampin treatment was tested in a mouse model of device-related infection by using biophotonic imaging. Following treatment, the bioluminescent signals decreased to undetectable levels, irrespective of the age of the biofilm. After the final treatment, the signals rebounded in a time-dependent manner and reached those for the untreated mice. Readministration of rifampin was unsuccessful in eradicating reestablished infections, with the rifampin MICs for such bacteria being increased and with the bacteria having point mutations in the rpoB gene.

Journal Article

Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents, Phytogenic; Bioware; Cell Line, Tumor; Drug Carriers; Female; Humans; Mice; Nanoparticles; Ovarian Neoplasms; Paclitaxel; Receptor, erbB-2; SKOV3-luc-D3 cells; Tissue Distribution; Xenograft Model Antitumor Assays

The benefit of polymeric immuno-nanoparticles (NPs-Tx-HER), consisting of paclitaxel (Tx)-loaded nanoparticles coated with anti-HER2 monoclonal antibodies (Herceptin, trastuzumab), in cancer treatment was assessed in a disseminated xenograft ovarian cancer model induced by intraperitoneal inoculation of SKOV-3 cells overexpressing HER2 antigens. The study was focused on the evaluation of therapeutic efficacy and biodistribution of NPs-Tx-HER compared to other Tx formulations. The therapeutic efficacy was determined by two methods: bioluminescence imaging and survival rate. The treatment regimen consisted in an initial dose of 20mg/kg Tx administered as 10mg/kg intravenously (IV) and 10mg/kg intraperitonealy (IP), followed by five alternative IP and IV injections of 10mg/kg Tx every 3 days. The bioluminescence study has clearly shown the superior anti-tumor activity of NPs-Tx-HER compared to free Tx. As a confirmation of these results, a significantly longer survival of mice was observed for NPs-Tx-HER treatment compared to free Tx, Tx-loaded nanoparticles coated with an irrelevant mAb (Mabthera, rituximab) or Herceptin alone, indicating the potential of immuno-nanoparticles in cancer treatment. The biodistribution pattern of Tx was assessed on healthy and tumor bearing mice after IV or IP administration. An equivalent biodistribution profile was observed in healthy mice for Tx encapsulated either in uncoated nanoparticles (NPs-Tx) or in NPs-Tx-HER. No significant difference in Tx biodistribution was observed after IV or IP injection, except for a lower accumulation in the lungs when NPs were administered by IP. Encapsulated Tx accumulated in the organs of the reticulo-endothelial system (RES) such as the liver and spleen, whereas free Tx had a non-specific distribution in all tested organs. Compared to free Tx, the single dose injection (IV or IP) of encapsulated Tx in mice bearing tumors induced a higher tumor accumulation. However, no difference in overall tumor accumulation between NPs-Tx-HER and NPs-Tx was observed. In conclusion, the encapsulation of Tx into NPs-Tx-HER immuno-nanoparticles resulted in an improved efficacy of drug in the treatment of disseminated ovarian cancer overexpressing HER2 receptors.

Journal Article

Animals; Antigen Presentation; Antigens, Neoplasm; B16-F10-luc-G5 cells; Bioware; B-Lymphocytes; Cell Adhesion; Cell Line, Tumor; Cell Movement; dendritic cells; Female; Lectins, C-Type; Lymphatic Metastasis; Lymphatic System; Macrophages; Male; Mannose-Binding Lectins; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Mice, Knockout; Receptors, Cell Surface; T-Lymphocytes

Macrophage mannose receptor (MR) participates in pathogen recognition, clearance of endogenous serum glycoproteins, and antigen presentation. MR is also present on lymphatic vessels, where its function is unknown. Here we show that migration of lymphocytes from the skin into the draining lymph nodes through the afferent lymphatics is reduced in MR-deficient mice, while the structure of lymphatic vasculature remains normal in these animals. Moreover, in a tumor model the primary tumors grow significantly bigger in MR(-/-) mice than in the wild-type (WT) controls, whereas the regional lymph node metastases are markedly smaller. Adhesion of both normal lymphocytes and tumor cells to lymphatic vessels is significantly decreased in MR-deficient mice. The ability of macrophages to present tumor antigens is indistinguishable between the 2 genotypes. Thus, MR on lymphatic endothelial cells is involved in leukocyte trafficking and contributes to the metastatic behavior of cancer cells. Blocking of MR may provide a new approach to controlling inflammation and cancer metastasis by targeting the lymphatic vasculature.

Journal Article

Animals; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Bioware; Dacarbazine; DNA Damage; DNA Modification Methylases; DNA Repair; DNA Repair Enzymes; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; MDA-MB-231-D3H2LN cells; Mice; Mice, SCID; Neoplasm Metastasis; Neoplasm Transplantation; Tumor Suppressor Proteins

PURPOSE ABT-888, currently in phase 2 trials, is a potent oral poly(ADP-ribose) polymerase inhibitor that enhances the activity of multiple DNA-damaging agents, including temozolomide (TMZ). We investigated ABT-888+TMZ combination therapy in multiple xenograft models representing various human tumors having different responses to TMZ. EXPERIMENTAL DESIGN ABT-888+TMZ efficacy in xenograft tumors implanted in subcutaneous, orthotopic, and metastatic sites was assessed by tumor burden, expression of poly(ADP-ribose) polymer, and O(6)-methylguanine methyltransferase (MGMT). RESULTS Varying levels of ABT-888+TMZ sensitivity were evident across a broad histologic spectrum of models (55-100% tumor growth inhibition) in B-cell lymphoma, small cell lung carcinoma, non-small cell lung carcinoma, pancreatic, ovarian, breast, and prostate xenografts, including numerous regressions. Combination efficacy in otherwise TMZ nonresponsive tumors suggests that TMZ resistance may be overcome by poly(ADP-ribose) polymerase inhibition. Profound ABT-888+TMZ efficacy was seen in experimental metastases models that acquired resistance to TMZ. Moreover, TMZ resistance was overcome in crossover treatments, indicating that combination therapy may overcome acquired TMZ resistance. Neither tumor MGMT, mismatch repair, nor poly(ADP-ribose) polymer correlated with the degree of sensitivity to ABT-888+TMZ. CONCLUSIONS Robust ABT-888+TMZ efficacy is observed across a spectrum of tumor types, including orthotopic and metastatic implantation. As many TMZ nonresponsive tumors proved sensitive to ABT-888+TMZ, this novel combination may broaden the clinical use of TMZ beyond melanoma and glioma. Although TMZ resistance may be influenced by MGMT, neither MGMT nor other mechanisms of TMZ resistance (mismatch repair) precluded sensitivity to ABT-888+TMZ. Underlying mechanisms of TMZ resistance in these models are not completely understood but likely involve mechanisms independent of MGMT.