According to a new study led by Dr Camille Ettelaie of the University of Hull and Dr Anthony Maraveyas, consultant oncologist from Hull’s Castle Hill Hospital, anti-coagulants known collectively as Low Molecular Weight Heparin (LMWH), that are given routinely to individuals with cancer in order to treat or lower the risk of thrombosis, might restrain the growth and spread of tumors as well.
The study is published online in the journal Biochimica et Biophysica Acta -Molecular Basis of Disease. For the first time the study has revealed that LMWH can reduce the levels of a tissue factor (a protein that contributes to clotting) being secreted by tumors.
Dr Ettalaie explained:
“Tissue factor’s role in healthy people is to promote blood clotting in wounds and aid repair. However, in cancer, we found that tumors secrete tissue factor as an inflammatory response to their interaction with growth factors in the blood, which they hijack to help them grow and spread. High levels of tissue factor are known to cause thrombosis, which is one reason why cancer patients are particularly at risk of developing lethal deep vein blood clots.
In addition, our previous research has shown that tumor cells which express high levels of tissue factor are more invasive, and other reports show that they metastasize rapidly and are resistant to therapy. Therefore, finding new ways to suppress the expression of tissue factor are crucial.”
Observational investigations have revealed that individuals who are treated with LMWH to thin their blood also had lower levels of tissue factor. Several clinicians, including Dr Maraveyas, had noted that clinical outcomes, such as survival, for those treated with LMWH appear to be better. Up till now, this remained unexplained.
The researchers investigated the effects of LMWH doses, the same as those given therapeutically to individuals with cancer, on pancreatic cancer cells – a severely aggressive cancer, with high levels of tissue factor. They then conducted similar tests of four other cancer cell types – breast, melanoma, colorectal and ovarian. They discovered that for each of the five cancer types, LMWH suppressed the cell’s interaction with growth factors, preventing tissue factor from being secreted.
Dr Maraveyas stated:
“To see this process suppressed in highly lethal cancer like pancreatic cancer and in a further four cancer types with high levels of tissue factor, raises the possibility of a universal treatment strategy that could benefit all cancer patients.”
Results from the study indicate that the suppression of tissue factor was a slow process, which according to Dr Maraveyas, supports a more protracted use of low molecular weight heparin:
“What we have here is experimental evidence that a drug that is already known to be safe in humans as an anti-coagulant may also suppress tumor growth directly and reduce resistance to treatment. I think this would also be a very useful way of lowering the risk of tumor regrowth in between chemotherapy and radiotherapy sessions.”
The study was funded in part by the Castle Hill Hospital Charity Fund.
Written by Grace Rattue