Scientists at the Queensland Institute of Medical Research (QIMR) have discovered two molecules from pineapple stems that show anti-tumour activity in laboratory studies. One molecule called CCS blocks a protein called Ras, which is defective in approximately 30% of all cancers. The other molecule called CCZ, stimulates the body's own immune system to target and kill cancer cells.
Dr Mynott and her team at QIMR discovered CCS and CCZ while investigating the properties of bromelain, a crushed pineapple stem extract. Bromelain is a rich source of enzymes and is widely used as a meat tenderiser, to clarify beer and tan leather hides. They discovered that bromelain also had some pharmacological properties and could activate specific immune cells while, simultaneously, blocking the immune function of other cells.
"We suspected that different components of the crude mixture might be responsible for bromelain's biological effects. In searching for these components, we discovered the CCS and CCZ proteins and found that they could block growth of a broad range of tumour cells, including breast, lung, colon, ovarian and melanoma," said Dr Mynott.
According to the National Cancer Institute, cancer has now overtaken cardiac disease as the largest killer in the USA. The incidence of cancer increases with age, with approximately 80% of cancers occurring in people over the age of 55. The major limitation of current cancer therapies is they are non-specific and affect both normal and tumour cells. Future cancer treatments will be rational and highly specific to selectively destroy the cancer cells, counteracting the mechanisms by which cancers grow. Data already generated show that CCS and CCZ have the desired specificity and selectivity.