Tau proteins interact with tubulin to stabilise microtubules and are abundant in neurons but less common in non-neuronal cells. Recently, tau proteins have received a bad press because of the association between tangles of hyperphosphorylated tau and Alzheimer’s disease and now researchers at the University of Maryland have reported that tau proteins may also play a role in tumour metastasis. Tau was found to promote formation of extensions of the plasma membrane or ‘microtentacles’ on breast cancer cells which break away from the primary tumour and circulate in the bloodstream. The microtentacles then increase the ability of the cells to attach to the walls of capillaries in the lung and seed new tumours. Tau protein has previously been associated with chemotherapy-resistant breast cancers and a poor prognosis but this is the first time that it has been implicated in metastasis. In the present study involving 102 breast cancer patients, 52% showed tau expression in metastases and 26% showed significantly increased tau expression as the disease progressed.
The team hope that drugs might be identified which will prevent the growth of microtentacles and inhibit tumour metastasis. Although current breast cancer treatments are often effective in treating the primary tumour, they are less effective in treating metastatic cancer which can develop years after the primary tumour is discovered and is the leading cause of death in cancer patients.
The study is published in the journal Oncogene.