Luciferase Stable Cell Line Application: In Vivo Imaging

Luciferase stable cell lines are useful in life science research. In recent years, the global medical and health industry has developed rapidly, and new drug research and development has gradually become a key research direction for scientific research institutions and pharmaceutical companies. In particular, in vivo imaging has become a valuable tool for drug discovery. Currently, in vivo imaging system (IVIS) for small animals has two major experimental methods for drug R&D: bioluminescence and fluorescence.

▍  Method and Application of Bioluminescence In Vivo Imaging Technology (i.e. luciferase cell imaging)

Bioluminescence mainly uses luciferase to label genes, cells, and living animals. The method of labeling cells is basically to insert the luciferase gene into the expected observed cell chromosome through molecular biological cloning technology, and then screen the cloned cells to cultivate a cell line that can stably express luciferase, these labeled cells are called luciferase labeled cell lines. The luciferase stable cell line was then injected to mice. A single injection of luciferin (the substrate of luciferase) into model mice can maintain the luminescence of luciferase labeled cells in their bodies for 30-45 minutes. Because each luciferase catalyzed reaction can only produce one photon, which cannot be observed by the naked eye, imaging systems coupled with a highly sensitive cooled CCD camera, and specially designed imaging cassettes and imaging software, are required to observe and record these photons.

In simple terms, after reacting with the substrate, luciferase produces chemiluminescence. This light is produced by chemical reactions and does not require excitation. The equipment records the number of photons detected per unit time, which is equivalent to directly and quantitatively recording the number of cells expressing luciferase.

For example, in the article "Generation of retrovirus mediated Luciferase gene stable cell lines and their bioluminescence imaging detection" written by Haijuan Wang et al., researchers stably expressed the luciferase reporter gene in mouse colon cancer cell line CT26, human colon cancer cell line HT-29, human liver cancer cell line SMMC-7721, etc. A significant linear relationship between the number of Luciferase positive cells and the luminous flux value in the bioluminescent imaging system was observed by inoculating different numbers of Luciferase stable cells in the culture dishes and different regions of the nude mouse (dorsal subcutaneous or caudal vein).

▍  Why Does Cancer Research Mainly Use Luciferase-labeled Bioluminescence?

The main reason is that bioluminescence can obtain more authentic and reliable data. Although the fluorescence signal is far stronger than bioluminescence, the background noise generated by non specific fluorescence makes its signal to noise ratio far lower than bioluminescence. These background noises cause low sensitivity in fluorescence imaging. Most of the currently published articles use luciferase cell imaging in living animals. Compared to traditional caliper measurement, luciferase labeled bioluminescence has the advantages of accuracy and continuous measurement.

We know that caliper measurements are limited to subcutaneous tumors and cannot monitor in situ or metastatic tumors in vivo. The most traditional method is to obtain many tumor bearing mice at one time, execute a batch at each stage, and take out the tumor from the mice to measure. This is clearly an inefficient approach. IVIS can quantitatively detect tumors in situ, metastatic tumors, and spontaneous tumors in mice over a long period of time, in stages, and without trauma.

▍  Vitro Biotech Performed Mouse Tumorigenicity Tests In Luciferase Stable Cell Lines

▍  How to Perform In Vivo Luciferase Cell Imaging of Mice?

The basic principle of in vivo imaging of small animals is to use software and imaging systems to observe. When the substrate luciferin is injected into tumor-bearing mice (which are injected by luciferase labeled cancer cell lines) , luciferase can catalyze the oxidation of luciferin to oxyluciferin, which emits biological fluorescence during the oxidation process, and statistical data can be obtained within a few minutes. This JOVE video shows a detailed tutorial of how to perform in vivo imaging of luciferase cells in mice.

In this experiment, the most critical factor is to obtain a stable cell line that can efficiently express luciferase. Through lentivirus transduction and antibiotics screening, an ideal luciferase overexpression cell line can be obtained. However, the time and labor costs involved in this process are huge, so you can select an in-stock luciferase cell line at Vitro Biotech. We have ten years of experience in the stable cell line generation, and we have 133 Luciferase cell lines in our product list.

If your preferred luciferase cell line is not on the list, please contact us to get a quote for the stable cell line customization service. A luciferase labeled cell line can be obtained as soon as 4 weeks.