Bioluminescent imaging (BLI) to improve and refine traditional murine models of tumor growth and metastasis

Abstract

Bioluminescent imaging (BLI) permits sensitive in vivo detection and quantification of cells specifically engineered to emit visible light. Three stable human tumor cell lines engineered to express luciferase were assessed for their tumorigenicity in subcutaneous, intravenous and spontaneous metastasis models. Bioluminescent PC-3M-luc-C6 human prostate cancer cells were implanted subcutaneously into SCID-beige mice and were monitored for tumor growth and response to 5-FU and mitomycin C treatments. Progressive tumor development and inhibition/regression following drug treatment were observed and quantified in vivo using BLI. Imaging data correlated to standard external caliper measurements of tumor volume, but bioluminescent data permitted earlier detection of tumor growth. In a lung colonization model, bioluminescent A549-luc-C8 human lung cancer cells were injected intravenously and lung metastases were monitored in vivo by whole animal imaging. Anesthetized mice were imaged weekly allowing a temporal assessment of in vivo lung tumor growth. This longitudinal study design permitted an accurate, real-time evaluation of tumor burden in the same animals over time. End-point bioluminescence measured in vivo correlated to total lung weight at necropsy. For a spontaneous metastatic tumor model, bioluminescent HT-29-luc-D6 human colon cancer cells implanted subcutaneously produced metastases to lung and lymph nodes in SCID-beige mice. Both primary tumors and micrometastases were detected by BLI in vivo. Ex vivo imaging of excised lung lobes and lymph nodes confirmed the in vivo signals and indicated a slightly higher frequency of metastasis in some mice. Levels of bioluminescence from in vivo and ex vivo images corresponded to the frequency and size of metastatic lesions in lungs and lymph nodes as subsequently confirmed by histology. In summary, BLI provided rapid, non-invasive monitoring of tumor growth and regression in animals. Its application to traditional oncology animal models offers quantitative and sensitive analysis of tumor growth and metastasis. The ability to temporally assess tumor development and responses to drug therapies in vivo also improves upon current standard animal models that are based on single end point data.

Modulating metastasis by a lymphangiogenic switch in prostate cancer

“…These respective goals were achieved by a noninvasive optical bioluminescence imaging approach that enabled us to monitor the development of distant metastasis in real-time and to locate and quantify micrometastatic lesions in isolated tissues. 22,23 We show here that lymphangiogenesis and VEGF-C expression correlated with lymph node and lung metastasis in the 4 different prostate cancer cell lines examined. Further, we demonstrate that overexpression of VEGF-C resulted in the stimulation of tumor lymphangiogenesis generating a switch from a low-metastatic to a highly-metastatic tumor.…”

Design and modification of EGF4KDEL 7Mut, a novel bispecific ligand-directed toxin, with decreased immunogenicity and potent anti-mesothelioma activity

“…Traditionally, treatment outcomes in intraperitoneal xenograft models of MM were only able to be determined using expensive long-term survival studies or by euthanizing animals to count tumour colonies (Frizelle et al, 2000;Stewart et al, 2002). By introducing the firefly luciferase gene into H2373 and H513 we were able to monitor the effect of treatment on tumour burden on a weekly basis using a highly sensitive and well-validated bioluminescent imaging technology that directly correlates with actual tumour volume (Jenkins et al, 2003). Furthermore, using H2373 cells stably expressing green fluorescent protein for our in vivo study, we were able to accurately assess and quantitate peritoneal tumour colonies at the completion of treatment.…”

Efficacy assessment of sustained intraperitoneal paclitaxel therapy in a murine model of ovarian cancer using bioluminescent imaging

“…We observed strong correlations between the bioluminescent signal with tumour weight and cell viability and thus employed bioluminescent imaging as a tool to investigate the effects of sustained vs intermittent intraperitoneal administration of PTX on ovarian tumour responsiveness. There are a number of BLI studies monitoring tumour response to different treatments (Contag et al, 1997;Jenkins et al, 2003a;McCaffrey et al, 2003;Hollingshead et al, 2004;Peter et al, 2007); however, our report is the first to explore the potential of sustained intraperitoneal chemotherapy with real-time progressive observation in a human ovarian cancer model.…”

“…Although BLI has emerged as a powerful tool for the monitoring of in vivo disease progression and regression, its use in endogenous tumours is limited as it relies on the expression of a foreign gene and therefore cannot be directly translated into the clinic (Hollingshead et al, 2004). Furthermore, it is restricted to small research animals or to the superficial tissues of larger animals as signal intensity may be attenuated by scattering (Jenkins et al, 2003a). Bioluminescent imaging is two-dimensional and unable to obtain in-depth information; however, the development of bioluminescent tomography has overcome these limitations and three-dimensional images are readily generated (Kumar et al, 2007;Zhang et al, 2008).…”