Arsenic has a long history in medicine, with arsenic trioxide (As2O3) first being used in the treatment of some conditions as early as 2000 BC. Today, arsenic trioxide is recognized as a potent chemotherapeutic agent and is used in the treatment of hematological malignancies. Unfortunately, As2O3 has not demonstrated efficacy in the treatment of solid tumors as it is rapidly cleared, necessitating toxic doses to reach therapeutic concentrations.
Recently, in a wonderful example of cutting-edge technology applied to old world solutions, Dr. Richard Ahn and colleagues at Northwestern University have developed a nanoparticulate formulation of As2O3 encapsulated in liposomal vesicles (nanobins), which demonstrated the ability to deliver therapeutic concentrations of arsenic trioxide to triple-negative breast carcinomas in a murine model. The nanobin technology effectively shields healthy cells from its payload while maintaining stability. Currently the group is working to incorporate antibodies on the surface of the nanobins to improve their efficacy, and to deliver multiple drugs.
From the press release:
The nanobin consists of nanoparticulate arsenic trioxide encapsulated in a tiny fat vessel (a liposome) and coated with a second layer of a cloaking chemical that prolongs the life of the nanobin and prevents scavenger cells from seeing it. The nanobin technology limits the exposure of normal tissue to the toxic drug as it passes through the bloodstream. When the nanobin gets absorbed by the abnormal, leaky blood vessels of the tumor, the nanoparticles of arsenic are released and trapped inside the tumor cells.
The nanoparticle technology has great potential for other existing cancer drugs that have been shelved because they are too toxic or excreted too rapidly, Cryns noted. “We can potentially make those drugs more effective against solid tumors by increasing their delivery to the tumor and by shielding normal cells from their toxicity,” he said. “This nanotechnology platform has the potential to expand our arsenal of chemotherapy drugs to treat cancer.”
Abstract in Clinical Cancer Research A Novel Nanoparticulate Formulation of Arsenic Trioxide with Enhanced Therapeutic Efficacy in a Murine Model of Breast Cancer
Press release New Arsenic Nanoparticle Blocks Aggressive Breast Cancer…
Image credit: Wikipedia: Arsenic trioxide…
