Antibody-like molecule that may help slow the progression of cancer

Scientists at Fox Chase Cancer Center say that they have created an antibody-like molecule that may help slow the progression of cancer.The researchers said that the molecule they nicknamed ALM was found to successfully attack two separate molecules on the surface of cancer cells at the same time, halting the growth of breast cancer cells in laboratory tests.Writing about their findings in the British Journal of Cancer, the researchers said that one day ALM might turn out to be a guidance system for delivering aggressive drugs directly to cancer cells.During the study, the research group observed that unlike naturally occurring antibodies that only bind to one specific target at a time, ALM could attach to two separate targets simultaneously.The researchers revealed that the molecules targets were two signalling proteins called ErbB2 and ErbB3, which connect to form a growth-promoting complex on the surface of many cancer cells, including head and neck cancer and drug-resistant breast cancer.“ALM grabs the ErbB2-ErbB3 complex strongly with both hands, as it were, providing a solid grip on the tumour and blocking the transmission of a growth signal within the cell,” said lead investigator Matthew Robinson, an associate member of Fox Chase and a researcher in the Fox Chase Head and Neck Cancer Keystone Program.“Potentially, it can become a platform for delivering therapeutics directly to cancer cells or a way of detecting the presence and location of individual tumours,” he added.Conducting experiments on mice, the researchers found that ALM could distinguish cancer cells from normal ones, for it preferentially selected tumour cells that expressed the receptor complex over normal cells that expressed low levels of both receptors individually.Robinson, however, insisted that treatment with ALM by itself was not really practical.“As a therapeutic, ALM would need to be taken daily, since it would be rapidly cleared from the body. While ALM can stop cancer cells from growing and possibly even spreading, it only has a modest ability to kill cancer cells,” he said.He suggested that it would be better to think of ALM as a delivery system rather than as a warrior.“Since ALM is so specific for its target and since its target is only found in great numbers on cancer cells it could be used to tow what would otherwise be considered toxic therapeutics directly to cancer cells, without harming nearby healthy cells. We are currently investigating how best to tether other molecules to the antibody in order to target metastatic breast cancer and related diseases,” he said.Robinson and his colleagues are currently studying ALMs diagnostic and therapeutic potential.