Use of the ODD-Luciferase Transgene for the Non-Invasive Imaging of Spontaneous Tumors in Mice

Abstract

BackgroundIn humans, imaging of tumors provides rapid, accurate assessment of tumor growth and location. In laboratory animals, however, the imaging of spontaneously occurring tumors continues to pose many technical and logistical problems. Recently a mouse model was generated in which a chimeric protein consisting of HIF-1α oxygen-dependent degradation domain (ODD) fused to luciferase was ubiquitously expressed in all tissues. Hypoxic stress leads to the accumulation of ODD-luciferase in the tissues of this mouse model which can be identified by non-invasive bioluminescence measurement. Since solid tumors often contain hypoxic regions, we performed proof-of-principle experiments testing whether this transgenic mouse model may be used as a universal platform for non-invasive imaging analysis of spontaneous solid tumors.Methods and Materials ODD-luciferase transgenic mice were bred with MMTV-neu/beclin1+/− mice. Upon injection of luciferin, bioluminescent background of normal tissues in the transgenic mice and bioluminescent signals from spontaneously mammary carcinomas were measured non-invasively with an IVIS Spectrum imaging station. Tumor volumes were measured manually and the histology of tumor tissues was analyzed.ConclusionOur results show that spontaneous mammary tumors in ODD-luciferase transgenic mice generate substantial bioluminescent signals, which are clearly discernable from background tissue luminescence. Moreover, we demonstrate a strong quantitative correlation between the bioluminescent tumor contour and the volume of palpable tumors. We further demonstrate that shrinkage of the volume of spontaneous tumors in response to chemotherapeutic treatment can be determined quantitatively using this system. Finally, we show that the growth and development of spontaneous tumors can be monitored longitudinally over several weeks. Thus, our results suggest that this model could potentially provide a practical, reliable, and cost-effective non-invasive quantitative method for imaging spontaneous solid tumors in mice.

Hypoxia-inducible factor prolyl hydroxylases as targets for neuroprotection by “antioxidant” metal chelators: From ferroptosis to stroke

“…A fusion protein containing the oxygen dependent degradation domain of HIF-1α (a.a. 530–652) fused to firefly luciferase under control of the cytomegalovirus (CMV) promoter has been previously used as a reporter for HIF-1α stabilization in high-throughput screening for novel activators of the hypoxic response [83], and for in vivo imaging [122] [117]. These studies employing the ODD-luc reporter have looked only at accumulation of the reporter as measured by luciferase activity assay, without investigating the mechanism by which it accumulates or is degraded.…”

Fast in vivo bioluminescence tomography using a novel pure optical imaging technique

“…So far, there are some commercial devices to implement the functionality of the tumor location reconstruction. IVIS Imaging System Spectrum is one of widespread application devices, 26,27 and it is also a pure optical 3D imaging system. To further investigate the performance of our POBT technique, we adopted this commercial system to acquire the°uorescence and white light images, and followed the guideline of the IVIS Living Imaging 3.0 software (PerkinElmer, USA) to achieve 3D light source reconstruction.…”

Targeting melanoma with front-line therapy does not abrogate Nodal-expressing tumor cells

“…25 IVIS has been shown to faithfully correlate with tumor growth in vivo. 26 Once the bioluminescence signal was detected, the mice were randomized into five different groups and treatment initiated ( Table 2). Treatment was maintained, as per the schedule described in Table 2, for the duration of the study.…”

“…Each cage contained three to five female mice, and offered chow (Certified Rodent Diet #7912, Harlan, Indianapolis, IN, USA) and water ad libitum unless otherwise specified. Environmental controls for the animal room were maintained between 68 and 75°F, a relative humidity of 30-70% and a minimum of 15 room air changes per hour The effects of study drug on tumor growth were evaluated during the in-life phase by IVIS imaging (radiance) 26 and by lung weights after euthanasia and excision from each mouse. Mice were killed at day 21 and lungs were removed, weighed, and photographed.…”