Journal Article

4T1-luc2, IVIS, Bioluminescence

The application of drug-loaded microbubbles (MBs) in combination with ultrasound (US), which results in an increase in capillary permeability at the site of US-sonication-induced MB destruction, may be an efficient method of localized drug delivery. This study investigated the mechanism underlying the US-mediated release of luciferin-loaded MBs through the blood vessels to targeted cells using an in vivo bioluminescence imaging (BLI) system. The luciferin-loaded MBs comprised an albumin shell with a diameter of 1234 +/- 394 nm (mean +/- SD) and contained 2.48 x 10(9) bubbles/mL; within each MB, the concentration of encapsulated luciferin was 1.48 x 10(-)(1)(0) mg/bubble. The loading efficiency of luciferin in MBs was only about 19.8%, while maintaining both the bioluminescence and acoustic properties. In vitro and in vivo BLI experiments were performed to evaluate the US-mediated release of luciferin-loaded MBs. For in vitro results, the increase in light emission of luciferin-loaded albumin-shelled MBs after destruction via US sonication (6.24 +/- 0.72 x 10(7) photons/s) was significantly higher than that in the luciferin-loaded albumin-shelled MBs (3.11 +/- 0.33 x 10(7) photons/s) (p < 0.05). The efficiency of the US-mediated release of luciferin-loaded MBs in 4T1-luc2 tumor-bearing mice was also estimated. The signal intensity of the tumor with US destruction at 3 W/cm(2) for 30 s was significantly higher than without US destruction at 3 (p = 0.025), 5 (p = 0.013), 7 (p = 0.012) and 10 (p = 0.032) min after injecting luciferin-loaded albumin-shelled MBs. The delivery efficiency was, thus, improved with US-mediated release, allowing reduction of the total injection dose of luciferin.

Journal Article

4T1-luc2, IVIS, Bioluminescence, Adenoviridae/genetics/*metabolism/physiology; Administration, Intravenous; Animals; Bone Neoplasms/secondary/*therapy; Cell Line, Tumor; Female; Humans; Immunocompetence; Luminescent Measurements/methods; Mammary Neoplasms, Experimental/pathology/*therapy; Mice; Mice, Inbred BALB C; Oncolytic Virotherapy/methods; Oncolytic Viruses/genetics/metabolism/physiology; Phosphorylation; Promoter Regions, Genetic; Protein-Serine-Threonine Kinases/genetics/*metabolism; Receptors, Transforming Growth Factor beta/genetics/*metabolism; Signal Transduction; Smad2 Protein/genetics/metabolism; Telomerase/genetics; Transforming Growth Factor beta1/genetics/metabolism; Transplantation, Isogeneic/methods; Tumor Stem Cell Assay/methods; Virus Replication

We have examined the effect of adenoviruses expressing soluble transforming growth factor receptorII-Fc (sTGFbetaRIIFc) in a 4T1 mouse mammary tumor bone metastasis model using syngeneic BALB/c mice. Infection of 4T1 cells with a non-replicating adenovirus, Ad(E1-).sTbetaRFc, or with two oncolytic adenoviruses, Ad.sTbetaRFc and TAd.sTbetaRFc, expressing sTGFbetaRIIFc (the human TERT promoter drives viral replication in TAd.sTbetaRFc) produced sTGFbetaRIIFc protein. Oncolytic adenoviruses produced viral replication and induced cytotoxicity in 4T1 cells. 4T1 cells were resistant to the cytotoxic effects of TGFbeta-1 (up to 10 ng ml(-1)). However, TGFbeta-1 induced the phosphorylation of SMAD2 and SMAD3, which were inhibited by co-incubation with sTGFbetaRIIFc protein. TGFbeta-1 also induced interleukin-11, a well-known osteolytic factor. Intracardiac injection of 4T1-luc2 cells produced bone metastases by day 4. Intravenous injection of Ad.sTbetaRFc (on days 5 and 7) followed by bioluminescence imaging (BLI) of mice on days 7, 11 and 14 in tumor-bearing mice indicated inhibition of bone metastasis progression (P<0.05). X-ray radiography of mice on day 14 showed a significant reduction of the lesion size by Ad.sTbetaRFc (P<0.01) and TAd.sTbetaRFc (P<0.05). Replication-deficient virus Ad(E1-).sTbetaRFc expressing sTGFbetaRIIFc showed some inhibition of bone metastasis, whereas Ad(E1-).Null was not effective in inhibiting bone metastases. Thus, systemic administration of Ad.sTbetaRFc and TAd.sTbetaRFc can inhibit bone metastasis in the 4T1 mouse mammary tumor model, and can be developed as potential anti-tumor agents for breast cancer.

Journal Article

B16-F10-luc2, B16F10-luc2, IVIS

The evidence that EMILIN1 (Elastic Microfibril Interface Located proteIN) deficiency in Emilin1(-/-) mice caused dermal and epidermal hyperproliferation and an abnormal lymphatic phenotype prompted us to hypothesize the involvement of this extracellular matrix component in tumor development and in lymphatic metastasis. Using the 12-dimethylbenz(alpha)anthracene/12-O-tetradecanoylphorbol-13-acetate (DMBA/TPA) two-stage model of skin carcinogenesis, we found that Emilin1(-/-) mice presented an accelerated formation, a higher incidence, and the development of a larger number of tumors compared with their wild-type littermates. EMILIN1-negative tumors showed more Ki67-positive proliferating cells and higher levels of pErk1/2. In these tumors, PTEN expression was lower. Emilin1(-/-) mice displayed enhanced lymphangiogenesis both in the tumor and in the sentinel lymph nodes. Accordingly, tumor growth and lymph node metastasis of transplanted syngenic tumors were also increased in Emilin1(-/-) mice. In vitro transmigration assays through lymphatic endothelial cells showed that EMILIN1 deficiency greatly facilitated tumor cell trafficking. Overall, these data established that EMILIN1 exerts a protective role in tumor growth, in tumor lymphatic vessel formation, as well as in metastatic spread to lymph nodes and reinforced the importance of its presence in the microenvironment to determine the tumor phenotype.

Journal Article

GL261-luc2, IVIS, Glioma, Biolumninescence imaging

The mouse glioma 261 (GL261) is recognized as an in vivo model system that recapitulates many of the features of human glioblastoma multiforme (GBM). The cell line was originally induced by intracranial injection of 3-methyl-cholantrene into a C57BL/6 syngeneic mouse strain (1); therefore, immunologically competent C57BL/6 mice can be used. While we use GL261, the following protocol can be used for the implantation and monitoring of any intracranial mouse tumor model. GL261 cells were engineered to stably express firefly luciferase (GL261-luc). We also created the brighter GL261-luc2 cell line by stable transfection of the luc2 gene expressed from the CMV promoter. C57BL/6-cBrd/cBrd/Cr mice (albino variant of C57BL/6) from the National Cancer Institute, Frederick, MD were used to eliminate the light attenuation caused by black skin and fur. With the use of albino C57BL/6 mice; in vivo imaging using the IVIS Spectrum in vivo imaging system is possible from the day of implantation (Caliper Life Sciences, Hopkinton, MA). The GL261-luc and GL261-luc2 cell lines showed the same in vivo behavior as the parental GL261 cells. Some of the shared histological features present in human GBMs and this mouse model include: tumor necrosis, pseudopalisades, neovascularization, invasion, hypercellularity, and inflammation (1). Prior to implantation animals were anesthetized by an intraperitoneal injection of ketamine (50 mg/kg), xylazine (5 mg/kg) and buprenorphine (0.05 mg/kg), placed in a stereotactic apparatus and an incision was made with a scalpel over the cranial midline. A burrhole was made 0.1mm posterior to the bregma and 2.3mm to the right of the midline. A needle was inserted to a depth of 3mm and withdrawn 0.4mm to a depth of 2.6mm. Two mul of GL261-luc or GL261-luc2 cells (10(7) cells/ml) were infused over the course of 3 minutes. The burrhole was closed with bonewax and the incision was sutured. Following stereotactic implantation the bioluminescent cells are detectable from the day of implantation and the tumor can be analyzed using the 3D image reconstruction feature of the IVIS Spectrum instrument. Animals receive a subcutaneous injection of 150mug luciferin /kg body weight 20 min prior to imaging. Tumor burden is quantified using mean tumor bioluminescence over time. Tumor-bearing mice were observed daily to assess morbidity and were euthanized when one or more of the following symptoms are present: lethargy, failure to ambulate, hunched posture, failure to groom, anorexia resulting in >10% loss of weight. Tumors were evident in all of the animals on necropsy.

Journal Article

PC-3M-luc2, PC3M-luc2, IVIS, Prostate Cancer, Bioware

Zoledronic acid (ZOL) is a drug whose potent anti-cancer activity is limited by its short plasma half-life and rapid uptake and accumulation within bone. We have recently proposed new delivery systems to avoid ZOL accumulation into the bone, thus improving extra-skeletal bioavailability. In this work, we have compared the technological and anti-cancer features of either ZOL-containing self-assembly PEGylated nanoparticles (NPs) or ZOL-encapsulating PEGylated liposomes (LIPO-ZOL). ZOL-containing NPs showed superior technological characteristics in terms of mean diameter, size distribution, and ZOL encapsulation efficiency, compared to LIPO-ZOL. Moreover, the anti-cancer activity of NPs in nude mice xenografted with prostate cancer PC3 cells was higher than that one induced by LIPO-ZOL. In addition, NPs induced the complete remission of tumour xenografts and an increase of survival time higher than that one observed with LIPO-ZOL. It has also to be considered that PC3 tumour xenografts were almost completely resistant to the anti-cancer effects induced by free ZOL. Both nanotechnological products did not induce toxic effects not affecting the mice weight nor inducing deaths. Moreover, the histological examination of some vital organs such as liver, kidney and spleen did not find any changes in terms of necrotic effects or modifications in the inflammatory infiltrate. On the other hand, NPs but not LIPO-ZOL caused a statistically significant reduction of the tumour associated macrophages (TAM) in tumour xenografts. This effect was paralleled by a significant increase of both necrotic and apoptotic indexes. The effects of the NPs were also higher in terms of neo-angiogenesis inhibition. These results suggest the future preclinical development of ZOL-encapsulating NPs in the treatment of human cancer.