Researchers in Singapore propose a new approach to destroy and combat cancer. This involves nanoparticles coated with amino acids that kill cancer cells from within.
The scientific community is working hard to find new treatments for cancer. In developed countries, cancer is the leading cause of death. The International Agency for Research on Cancer estimates that 9.6 million people worldwide will die of cancer in 2018.
Researchers in Singapore are proposing an original approach to cancer cell destruction. Their idea is based on the use of nanoparticles which, once they enter the abnormal cell, destroy it, following the example of the famous Trojan horse episode of Greek mythology.
Bringing nanoparticles into the cancer cells
Cancer cells are cells that proliferate uncontrollably. This happens when the cell accumulates genetic mutations that disturb its metabolism. To ensure their rapid reproduction, they require a higher proportion of essential amino acids. Many cancer cells overexpress the carrier LAT-1, whose task is to transport amino acids from the extracellular medium to the cytoplasm.
In view of this constant, researchers in Singapore have created a nanoparticle called nano-pPAAM, a porous silica with a diameter of about 30 nm on which they fixed L-phenylalanine, an essential amino acid. The nanoparticle travels on the LAT-1 carrier to satisfy the cell’s need for amino acids, but once inside, it leads the cell to suicide. In fact, the nanoparticles in the cytoplasm are considered to be intruders that the cell wants to eliminate at all costs.
In their publication, scientists have shown that their presence activates oxidative stress pathways, a cellular defense mechanism. But too high a concentration of ROS (reactive oxygen species) in the cell leads to its death by apoptosis. Here is, in theory, how nanoparticles work. Scientists then conducted in vitro and in vivo experiments to prove the efficacy of nano-pPAAMs on tumor size.
Nanoparticles reduce the size of tumors in mice
The first series of experiments were carried out in vitro. The breast cancer cells were cultivated in an agarose gel. After 24 hours of growth, the cancer cells formed spheroids. Scientists investigated the cell viability in spheroids when the cells were treated with nano-pPAAM. The nanoparticles had a less positive effect on spheroids: about 40% loss of cell viability when the cells were in this form, compared with almost 80% mortality when the cells were in carpet form.
The next step is to study the effect of an injection of nanoparticles in rats that received a xenograft of breast cancer. Scientists estimated the volume of the tumor at 5, 6, 7, and 14 days after the injection of nanoparticles. The latter caused the volume of the cancerous mass to be less than 300 mm3 compared to more than 1,200 mm3 in rats of the control group.
Nanoparticles will still need much research before they become a viable treatment for cancer, but one of the advantages of nanoparticles is the lack of side effects. No weight or behavior changes have occurred in rats injected with nano-pPAAM. Scientists at Nanyang Technology University in Singapore want to improve the specificity of these nanoparticles.