"Trojan Horse" Nanoparticles Kill Cancer Cells Without Drugs

Scientists have created a “Trojan horse” that sneaks anticancer nanoparticles into cancer cells and causes them to self-destruct without any drugs. The research is still in its early days, but the new method has already proved to be remarkably effective at killing cancer cells in a petri dish and reducing tumor growth in mice. 

Researchers at Nanyang Technological University Singapore (NTU Singapore) developed their “Trojan horse” by lacing an anti-cancer nanoparticle with a specific amino acid, known as L-phenylalanine, which cancer cells rely on to grow. The cancer cells seek to absorb the amino acid, unknowingly letting in this anticancer nanoparticle and causing them to self-destruct.

The nanoparticle is known as Nano-pPAAM, an ultrasmall particle with a diameter of 30 nanometers that has “excellent intrinsic anticancer and cancer-selective properties,” according to the paper. Once inside the cancer cells, Nano-pPAAM stimulates excessive reactive oxygen species (ROS) production, causing cancer cells to perish while remaining harmless to the healthy cells.

Reported in the journal Small, the team tested the efficacy of the nanoparticle in the lab and found that the nanoparticle killed about 80 percent of breast, skin, and gastric cancer cells, a rate comparable to some cancer drugs. It also significantly reduced tumor growth by around 60 percent in mice with human triple-negative breast cancer cells compared to control models.

"Against conventional wisdom, our approach involved using the nanomaterial as a drug instead as a drug-carrier. Here, the cancer-selective and killing properties of Nano-pPAAM are intrinsic and do not need to be 'activated' by any external stimuli. The amino acid L-phenylalanine acts as a 'trojan horse' – a cloak to mask the nanotherapeutic on the inside,” Assistant Professor Dalton Tay, lead study author from the School of Materials Science and Engineering at NTU Singapore, commented in a statement

"By removing the drug component, we have effectively simplified the nanomedicine formulation and may overcome the numerous technological hurdles that are hindering the bench-to-bedside translation of drug-based nanomedicine."

Previous research has suggested that cancer tumor growth can be slowed or prevented by “starving” cancer cells of these much-needed amino acids through fasting or special diets lacking in protein. Unfortunately, these diets are not always good for the patient, especially if they are already ill from their disease. This new method, however, would theoretically not have this negative side-effect.

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