Validating the use of a luciferase labeled breast cancer cell line, MDA435LCC6, as a means to monitor tumor progression and to assess the therapeutic activity of an established anticancer drug, docetaxel (Dt) alone or in combination with the ILK inhibitor, QLT0267

Abstract

A significant issue in drug efficacy studies is animal study design. Here we hypothesize that when evaluating new or existing therapeutics for the treatment of cancer, the location of disease burden will influence drug efficacy. To study this, Female NCr nude mice were inoculated with luciferase-positive human breast cancer cells (LCC6WT-luc) orthotopically (o.t.), intraperitoneally (i.p.) or intracardiacly (i.c.) to create localized, ascites or disseminated disease, respectively. Tumor development was monitored using bioluminescence imaging. Docetaxel (Dt) pharmacokinetics and distribution to sites of tumor growth were determined. Disease progression was followed in animals treated with Dt alone and in combination with QLT0267, an Integrin Linked Kinase inhibitor. Tumor related morbidity was most rapid when cells were inoculated i.c., where disease progression was observed in brain, ovaries, adrenal glands, and lungs. Dt pharmacokinetics were comparable regardless of the model used (mean plasma AUC0-24 hrs 482.6 ng/ml*hr), however, Dt levels were lowest in those tissues developing disease following i.c. cell injection. Treatment with low dose Dt (5 mg/kg) increased overall survival and reduced tumor cell growth in all three models but the activity was greatest in mice with orthotopic tumors. Higher doses of Dt (15 mg/kg) was able to prolong survival in animals bearing i.p. tumors but not i.c. tumors. Addition of QLT0267 provided no added benefit above Dt alone in the disseminated model. These studies highlight a need for more comprehensive in vivo efficacy studies designed to assess multiple disease models and multiple endpoints, focusing analysis of drug parameters on the most chemoresistant disease.

Bioluminescence Applications in Preclinical Oncology Research

“…BL data was quantified as photons emitted per second. The resulting graph ( Figure 1B) shows that the photons emitted are proportional to the number of cells plated (Kalra, Anantha et al 2011). These data can be used to estimate cell numbers from BL captured in an in vivo model.…”

“…Stable luciferase expressing cells can also be generated through transduction strategies (Nyati, Symon et al 2002;Kalra, Warburton et al 2009;Kalra, Anantha et al 2011;Yan, Xiao et al 2011 (Kalra, Warburton et al 2009;Kalra, Anantha et al 2011). …”

“…This method can capture minimal disease and/or micro-metastases at distant sites before the appearance of palpable nodules or clinical symptoms. Indeed, signals can be readily visualized immediately following inoculation of tumor cells (Kalra, Anantha et al 2011). To illustrate the sensitivity of BLI, Lipshutz et al used adenoviral vector carrying the luciferase gene to deliver luciferase to day 15 fetal mice through intraperitoneal delivery.…”

“…BLI has low background and any photon emission would be the result of engineered BL cells or genes. Finally, luciferase and its substrate, luciferin, are not toxic to mammalian cells, and no functional differences have been reported between cells expressing luciferase when compared with parental cell lines (Sweeney, Mailander et al 1999;Edinger, Cao et al 2002;Tiffen, Bailey et al 2010;Kalra, Anantha et al 2011).…”

Bioluminescence in drug development for cancer: Shedding light on therapeutic efficacy

“…4,12 In a report appearing in this issue of Cancer Biology & Therapy, Kalra and colleagues discuss the use of luciferase-labeled tumor cells to assess tumor response to cytotoxic drug intervention. 13 Optical imaging, either bioluminescent or fluorescent, is emerging as a sensitive, cost-effective and quantitative approach for noninvasive, longitudinal studies of tumor growth, metastasis and responsiveness to anticancer agents.…”