Killing Cancer Cells Using Plant Extract

A team of researchers from multiple institutions has developed a new way to kill certain cancer cells using plant extract.

The research team led by IIT Hyderabad has developed a lipid-based nanoparticle with a chlorophyll-rich extract from the plant Anthocephalus cadambaand a near-infrared dye to kill selective cancer cells.
In traditional photothermal therapy, heat is used to kill the cancerous cells. But, in the new method, the near-infrared dye generates heat when exposed to infrared light to kill the cancer cells.
The plant extract generated an excess amount of Reactive Oxygen Species (ROS) that caused cell death through autophagy.
Autophagy is the body’s own mechanism to remove damaged cells.
The method is safe as the extract is found to kill only cancer cells, while not causing any significant cell death when released in healthy cells.
This is because the extract did not increase the ROS insider normal cells and thus did not cause autophagy.
As per researchers, the heat generated by the near-infrared dye is used for destabilising the nanoparticle and releasing the extract into cancer cells.
The amount of dye used and the duration of illumination have been optimised so that the thermal effect triggers the extract release.

The research is a joint effort of researchers from IIT Bombay, University of Hyderabad, Bose Institute, Kolkata and IIT Hyderabad.
The research was published int eh journal Nature.

The research team has already demonstrated the thermal effect of the extract two years ago, but how it caused cancer cell death is now known.
By studying breast cancer cell lines, the researchers found that the extract is increasing the reactive oxygen species in the cancer cells and leading to autophagy.
Researchers observed that when using photothermal therapy, 50% of the cancer cells died but 45% grew back within a day.
When the photothermal therapy was used with the extract, there was no significant growth of cancer cells even after 48 hours showing the effectiveness of the extract. It had restricted cell growth.
The researchers confirmed cell death due to autophagy using a protein that is an autophagy marker. The amount of this protein was in excess in the cells, confirming autophagy as the cause of cancer cell death.
Also, the researchers observed the variations in the protein marker depended on the amount of extract used.
Further, the researchers confirmed the role of ROS in autophagy by testing with a ROS inhibitor that inhibits the generation of ROS in cells. When this was done, there was no significant cell death and there was no autophagy.

The testing of the nanoparticle with the plant extract was done on a moused model with breast cancer.
With the extract, the tumour volume reduced significantly.
Also, the researchers observed that there is no weight loss in the mouse indicating that the nanoparticle is biocompatible and causes no adverse health effects.