Cancer cells are not stupid. They protect themselves. Often after an initial round of chemotherapy, they produce large amounts of P-glycoprotein to kick out the chemical toxins and protect themselves from the next wave. Whole tumours can even build protective protein coats around themselves.
Scientists have now shown that a drug - XR9576 - can block P-glycoprotein both for cancer cells and for tumours. Dr Richard Callaghan at John Radcliffe Hospital, Oxford said that, "the core of a tumour is an extremely hostile environment for drugs to work in". Researchers treated two types of model tumour with vinblastine and doxorubicin. The balls of cancer cells with low P-glycoproteins were highly sensitive to both drugs, but those with high levels were up to 20 times more resistant to the first drug and 300 times more resistant to the second.
Scientists then proved XR9576 stopped the tumour developing this resistance.
Comment: Even the mighty Herceptin is being found to stop working in some cases because the cancer cells put up the shutters and a new drug is on its way in the USA to beat the defences - a sort of son of (daughter of?) Herceptin.
Alternative and complementary experts will argue that there are natural ways of dealing with these protein coats: Bromelain and papain (from pineapples and papaya) plus garlic are all supposed to be able to break down the protein coat.