Wednesday, 14 October 2015

Pregnancy-associated malaria research suggests a way to target cancer cells

Anopheles stephensi - a vector for the malaria parasite
Centers for Disease Control and Prevention

The malaria parasite Plasmodium falciparum is spread by mosquitos. It multiplies and resides in the liver and erythrocytes (red blood cells). In areas with heavy infection with Plasmodium most individuals acquire immunity. During pregnancy, however, infected erythrocytes are able to accumulate in the placenta. Pregnancy-associated malaria is an important cause of maternal and fetal morbidity and mortality (reviewed here).

Placenta from a stillbirth due to maternal malaria infection. Normal erythrocytes lack
a nucleus. Thus a nucleus indicates the presence of the malaria parasite.
Wikimedia Commons (CC BY-SA 3.0) uploaded by Nephron
Infected erythrocytes express surface proteins, among them VAR2CSA, which can bind to a placental variant of chondroitin sulphate A (CSA) expressed by syncytiotrophoblast.

A paper just out in Cancer Cell (here) shows that placental CSA is expressed by many types of cancer cell. This knowledge was leveraged to target cancer cells using recombinant VAR2CSA fused to diptheria toxin or conjugated to hemiasterlin. Human cancer cells in vitro were effectively killed by this means. Tumour growth and metastasis in mice could be inhibited by a similar approach.

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