A new targeted therapy for asbestos-related tumours has shown promise in an animal model. The results, reported in the open access journal BMC Cancer, raise hopes of a new therapy for this currently incurable cancer.
Malignant mesothelioma (MMs) is a rare form of cancer, most commonly caused by exposure to asbestos. It tends to be diagnosed decades after exposure occurs, so is rarely caught early. Current treatments, including surgery and chemotherapy, have limited efficacy and unpleasant side effects.
Traditional chemotherapeutic drugs work by destroying cells that divide quickly. As such, they're indiscriminate killers, destroying healthy dividing cells such as those in the bone marrow, digestive tract and hair follicles, as well as cancer cells. The result is an unwelcome mix of side-effects including a weakened immune system, gastrointestinal problems and hair loss. Targeted therapies, which are designed to kill cancer cells and leave healthy tissue unharmed, are highly sought after.
The new targeted therapy is a silica microparticle, coated in antibodies that recognise a protein produced by the tumour cells in large amounts. When the microparticles are injected into a mouse model of the cancer, the antibody helps the microparticles bind to the tumour cells, where they are then able to release their hidden inner cargo - the chemotherapy drug doxorubicin.
The new therapy is more effective and less toxic than doxorubicin alone, Brooke T. Mossman and colleagues report. Tumours shrank, the cancer cells proliferated less, and the animals were able more or less to maintain their weight and health throughout the treatment. Overall, the data suggest that targeted therapy may prove better than chemotherapy alone.
Using this targeting approach, the authors were able to reduce the dose of doxorubicin used four-fold thus almost eliminating side effects and toxicity. And because the treatment appears to reduce the number of proliferating tumour cells, it may prove useful early on, when pre-malignant or malignant MM cells are first observed, but before disease has been confirmed by histology.