Coloured scanning electron micrograph of an activated human macrophage

Immune cells called macrophages (pictured) ‘eat’ cancer cells after a supramolecule blocks the receptors cancer relies on to defend itself. Credit: Steve Gschmeissner/SPL/Getty

Cancer

Smart molecule aids natural cancer defences

Molecule with therapeutic potential stimulates immune cells that can gobble up tumour cells.

Cancer cells secrete signalling proteins that prevent immune cells called macrophages from attacking tumours. Ashish Kulkarni at the University of Massachusetts Amherst, Shiladitya Sengupta at the Brigham and Women's Hospital in Cambridge, Massachusetts, and their colleagues sought to create a molecular mechanism that could shut down these defences.

The team designed a ‘supramolecule’ that both inhibits a protein called CSF-1R, which receives signals that can switch off macrophages’ anti-tumour response, and blocks a pathway that tumours signal through to prevent macrophages engulfing them.

Treatment with the supramolecule reduced tumour growth in mice with aggressive breast cancer and melanoma, and increased the engulfment of cancer cells by macrophages.