[Show abstract][Hide abstract] ABSTRACT: The purpose of the study is to develop a mouse ocular melanoma model with human uveal melanoma cells that forms hepatic micrometastases. Human uveal melanoma Mel290 cells were transfected with a lentiviral-enhanced green fluorescent protein (EGFP) expression vector. Proliferation assays were performed by comparing Mel290-EGFP and Mel290 cells. After stable expression of EGFP and proliferation was ascertained, 1 x 10 Mel290-EGFP cells were introduced into NU/NU mice by posterior compartment (PC) inoculation or tail vein injection. Control groups were inoculated or injected with Mel290 cells. Ocular and hepatic frozen sections were examined by fluorescence microscopy, and the number of hepatic micrometastases was determined. EGFP expression was observed at 24 h after transfection. At 72 h after transfection, more than 70% of Mel290 cells expressed EGFP. At 45 days (six passages), 90% of Mel290 cells stably expressed EGFP. Histologic examination showed that Mel290-EGFP cells formed hepatic micrometastases after either PC inoculation or tail vein injection. A significant difference in the number of hepatic micrometastases between PC inoculation and tail vein injection (P<0.01) was observed. Mel290-EGFP cells stably expressed green fluorescent protein in vitro at 45 days (six passages). These cells formed hepatic micrometastases in NU/NU mice after PC inoculation or tail vein injection, with significantly more micrometastases developing in the PC inoculation model than after tail vein injection.
Full-text · Article · Apr 2008 · Melanoma Research
[Show abstract][Hide abstract] ABSTRACT: We previously established a bioluminescent transgenic mouse model, sPSA-Luc, with luciferase gene expression restricted to the prostate under the control of the supra prostate-specific antigen (sPSA) promoter. We now assess the feasibility of generating bigenic mice, TRAMP-Luc, with the sPSA-Luc as the founder strain crossbred with TRAMP (transgenic adenocarcinoma mouse prostate) mice, to evaluate non-invasively the metastatic potential of prostate tumors.
TRAMP-Luc mice were obtained as [C57BL/6 TRAMP x FVB sPSA-Luc] F1 offspring. Tumor development in 10 TRAMP-Luc males was followed by bioluminescence imaging from 8 to 24 weeks of age. Immunohistochemical (IHC) staining for T antigen (Tg), androgen receptor (AR), luciferase and/or pathological analysis verified the tumor distribution in the imaged tissues including prostate gland, lymph node and bone.
Group I animals that presented with no grossly visible tumors showed prostate-confined bioluminescence with slightly increased signal intensity with age. Group II animals that developed large tumors displayed a widely distributed and biphasic bioluminescence pattern. The peak was reached between 10 and 14 weeks of age, then markedly decreased or even disappeared beyond week 16, except for one mouse that showed an increased bioluminescence signal at the jaw bone and hind limbs at week 22. These tumors were shown by IHC to contain Tg but lost AR and luciferase beyond week 16 in poorly differentiated prostate tumors.
A direct correlation between bioluminescence emission and AR expression was found in TRAMP-Luc tumor progression model. This model allows non-invasive imaging of prostate cancer metastases to bone and soft tissues.
[Show abstract][Hide abstract] ABSTRACT: Bone metastasis is one of the major causes of morbidity and eventual mortality in prostate cancer patients. Unfortunately none of the currently available therapies is effective for curing bone metastasis in these patients. Tumor cell migration and metastasis is a highly coordinated process involving alternation of cell-cell junction and cell adhesion to extracellular matrix (ECM) proteins. Adhesionmolecules that involve in the metastatic cascade of prostate cancer presents an attractive target for therapeutic intervention. The L1 cell adhesion molecule has been implicated in a variety of motile processes in the developing nervous system and malignant diseases. In this communication we demonstrated that L1 was expressed on cell surface and in conditioned medium by androgen-independent and highly metastatic human prostate cancer cell lines DU145, PC3 but not androgen-dependent LNCaP and its derivative C4-2. Using genetic approach to manipulate the expression of L1 in PC3 and C4-2 cells, we found that unlike member-bound L1, which inhibited prostate cancer cell adherence to ECM and migration, due to the L1-mediated homotypic cell-cell interaction, the ectodomain of L1 secreted by cells showed chemotactic activity for L1-defected cancer cells in transwell migration assay. The possible role of soluble L1 on prostate cancer progression and dissemination was also investigated in vivo. The localization of L1 protein in clinical prostate cancer specimens was found at tumor-adjacent stroma and the invasive front of tumors but not the central, differentiated area of the tumor by immunohistochemistry analysis. The mean serum L1 levels in the bone metastatic prostate cancer patients (45.0±27.2 ng/ml, N=19) were significantly higher than patients with organ-confined tumors (28.4±22.2 ng/ml, N=30, p
[Show abstract][Hide abstract] ABSTRACT: The intricate intracellular communication between stromal and epithelial cells, which involves cell-cell-, cell-insoluble extracellular matrix- (ECM), and cell-soluble factor-mediated signaling processes, is an attractive target for therapeutic intervention in hormone-refractory and bone-metastatic prostate cancer. In the present study we demonstrated that androgen-independent PC3 prostate cancer cells adhered to and migrated on vitronectin (VN), a major noncollagenous ECM in mature bone, through the expression of alphav-containing integrin receptors alphavbeta1 and alphavbeta5 on the cell surface, as determined by antibody function blocking assay and flow cytometry analysis. Small interfering RNAs (siRNAs) targeting human integrin alphav markedly reduced their respective mRNA and protein expression in cells, resulting in nearly complete reduction in VN-mediated cancer progression in vitro. In vivo quantitative bioluminescence analysis of human prostate cancer bone xenografts demonstrated for the first time that intratumoral administration of liposome-encapsulated human alphav-siRNAs significantly inhibits the growth of luciferase-tagged PC3 tumors in skeleton, which was associated with decreased integrin alphav expression and increased apoptosis in tumor cells. This integrin-based gene therapy is particularly suitable for the treatment of prostate cancer bone metastasis.