A novel luciferase enzyme has been used in the development
of a cytotoxic assay to determine cell death, shows study from the Keck School of Medicine of USC.
- Novel luciferase
enzyme from marine dwellers allows to develop Matador assay which can
track efficacy of cancer therapies.
- The florescence
producing luciferases are released by dead and dying cells and can be
- The assay is
highly sensitive, specific, rapid, and can be performed in a single step
without the need for expensive equipment.
enzyme, extracted from deep sea dwellers is responsible for bioluminescence,
giving these creatures their glow. Using this particular property of the
enzyme, the team has developed the Matador
assay which is used to measure cell death. The cytotoxic assay may allow to
track progression of cancer immunotherapies
by allowing oncologists to visualize if the therapy
was successful in killing the cancer cells. The study is published in the
journal Scientific Reports.
While cancer immunotherapies
including chimeric antigen receptor-T (CAR-T) cells are the most promising
areas in cancer research, these are also the most difficult due to limited
testing methods. Testing methods are critical to determine if the cancer
therapy was successful in killing cancer cells.
"Radioactive chromium release assay is the gold
standard for testing whether an immunotherapy
kills cancer cells. This method is expensive, complicated and requires special
says co-author Preet M. Chaudhary, MD, PhD, professor of medicine at the Keck School.
‘The Matador assay is so specific that it detects cell death even at a single cell level.’
The hazards associated with the
harmful effects of radioactivity and disposal of that radioactive waste prompt
researchers to look for other safer alternatives for testing efficacy of cancer
The novel cytotoxicity assay involves expression of the luciferase
enzyme in target cells.
It is incorporated in such a manner that only healthy cells can retain
the enzyme; dead or dying cells release the
compound and as a result produce fluorescence. The released fluorescence can be
measured using a luminometer
and gives an idea of how many cells are getting
killed and where.
"In our hands, the Matador
assay can detect cell death in as little as 30 minutes, which can ultimately
translate to more expedient treatments for patients getting cellular
immunotherapies such as CAR-T
," Chaudhary says.
"It could potentially play a
role in screening other types of anticancer agents
or even measuring environmental
To validate the ability to detect
cytotoxicity, more than 80 cell lines were created that stably expressed
luciferase in the cytosol. The study did not come across any cell line in which
the Matador assay did not work as expected. In
all the cell lines, there was significant increase in the luciferase activity
upon induction of cell death.
Highlights of the assay:
- Highly sensitive,
specific and fast
- Does not require
- Detects cell
death at a single cell level
- Luciferase is
retain their activity even after thawing and freezing
- Matta, H. et al. Development and characterization of a novel luciferase based cytotoxicity assay. Scientific Reports 8, (2018).