Madhu Biyani of Kanazawa University and colleaguesFinddeveloped a DNA-derived chemical that binds to and inhibits CYP24, while also showing promising antiproliferative activity. In addition, the research team conducted extensive research into the underlying molecular mechanisms at work.
The researchers tested a large number of DNA aptamers, which are single-stranded DNA fragments with specialized three-dimensional structures that can bind to certain target molecules and, upon binding, produce a functional effect. They looked for DNA inducers that bind to CYP24, but not CYP271B, a similar enzyme responsible for vitamin D3 synthesis.
The initial long list of 18 candidate inducers was narrowed down to 11 candidates with specific molecular structures. The researchers tested these 11 representative aptamers for their ability to inhibit CYP24 in vitro, leaving four candidates that inhibited CYP24 but not CYP27B1, one of which (Apt-7) was retained for further study .
Biyani and colleagues modeled the binding of Apt-7 to CYP24. They obtained a molecular docking scheme and examined it experimentally by comparing the behavior of mixtures of vitamin D3 and CYP24 with Apt-7. Simulations and experiments show that Apt-7 leads to inhibition of CYP24 activity, what happens is that the aptamer may interfere with the active site of the enzyme. The researchers also performed high-speed atomic force microscopy of the real-time binding of CYP24 and Apt-7, confirming the simulated molecular docking.
Finally, the team investigated the effects of Apt-7 at the cellular level by introducing the molecule into cancer cells. They observed significant CYP24 inhibition in a cancer cell line known to overexpress the CYP24 enzyme, thereby exhibiting antiproliferative activity. Biyani and colleagues are quoted as saying that the findings “clearly describe and suggest that DNA-inducing agent-based molecules may be a promising lead candidate for anticancer therapy”.