A new chemotherapy technique: light-based chemotherapy

Many chemotherapy drugs have been known and used for years, including taxanes obtained from yew trees in the late 1970s. Their best-known members, used in many cancers, are paclitaxel and docetaxel. A new light-based technique has been shown to increase their effectiveness up to 250-fold without increasing side effects.

Conventional chemotherapy acts on cancer cells but cannot directly target them, so it also disrupts normal cells and causes side effects. These prevent escalation to potentially more effective high doses.

Thousands of studies annually seek to improve existing drugs. A striking study published in Cell on 9 July suggests light can control activity of chemotherapy drugs affecting cell division.

Taxanes are microtubule inhibitors. Microtubules are protein molecules forming the cell skeleton; one function is transferring genetic information into newly forming cells during division. Taxanes disrupt microtubules and prevent division, stopping cancer cells from multiplying.

Making microtubule inhibitors act only on cancer cells has become a major research topic. This led to discovery of a highly precise method for light-based control of microtubule-inhibiting medicines.

This newly developed technique seems to overcome dose limits preventing microtubule-inhibiting chemotherapy drugs from achieving the desired effectiveness. Researchers examined these drugs particularly under blue light and found that they became more active in cancerous tissue without affecting neighboring normal cells. What makes these drugs more effective under blue light?

Under blue light, drug components called photostatins change. At different light wavelengths, photostatins switch between -cis and -trans isomeric forms, making biological activity on=active or off=inactive . Microtubule inhibitors were most active under blue light and least active in darkness.

This photostatin switching was demonstrated with UV-Vis spectroscopy imaging equipment (see the news image).

In conclusion,these still very young photopharmacology applications are promising but need scientific support before clinical use. Meanwhile, daily discoveries in cancer treatment keep our hope and excitement alive.

Keywords: light-based chemotherapy, taxanes, paclitaxel, docetaxel, microtubule inhibitors, chemotherapy side effects, blue light, photostatin, photopharmacology