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Scientists study the ability of sweet wormwood in fighting breast cancer

Breast cancer is the second leading cause of cancer-related deaths in women across the world. As per an estimate by the World Health Organisation, 570,000 women died from breast cancer in 2015 alone. Although genetic factors and the female sex hormone oestrogen play a role in the occurrence of breast cancer, several other factors like increased iron content in the body might also enhance the risk. Now, a new study by researchers from the Institute of Life Sciences, Bhubaneswar, Odisha, have explored how a chemical present in the medicinal herb sweet wormwood can kill breast cancer.

In a healthy body, iron plays a vital role in the growth and maintenance of cells. Cancerous cells demand more iron to proliferate in the body. Hence they have many receptors of transferrin, a protein that helps transport iron, on the cell surface. Studies have shown that artemisinin, a chemical compound present in the medicinal herb sweet wormwood (Artemisia annua), reacts with iron, present in the haemoglobin in red blood cells, to form free radicals. When formed inside the cells, the carbon-based free radicals promote cell death by reacting with the proteins and lipids present in the cell. Hence, artemisinin can kill cells containing iron in large quantities.

In this study, published in the journal BMC Cancer, the researchers have detailed the molecular mechanism behind how artemisinin prevents invasion and migration of breast cancer to other parts of the body. They treated breast cancer cells with artemisinin and recorded the effects, including changes in the gene and protein expressions.

The study revealed that small dosage of artemisinin was enough to inhibit breast cancer cells. Migration of cancer cells from its origin to other parts of the body causes cancer to spread rapidly, and it is a challenge to stop this. However, the study showed that cells treated with artemisinin had high quantities of E-cadherin, a protein that promotes cell-cell adhesions and thus prevents the migration of cells.

The study also showed that treating cells with artemisinin alters the expression of genes involved in development, proliferation and migration of breast cancer cells. In a healthy body, ‘tumor suppressor genes’ in our cells slow down the rate of spread of cells and protect us from cancer. Treating cells with artemisinin enhanced the expression of these genes. The researchers also observed increased expression of cancer-causing oncogenes after treating the cells with artemisinin.

Our body has a mechanism of destroying cells that are no longer needed or harmful, in a process called apoptosis. Cancer cells subvert the process of apoptosis and hence result in uncontrolled cell growth. The present study revealed that artemisinin induces apoptosis in cancer cells, thus arresting the progression of cancer. For the first time, the researchers have shown that it inhibits specific enzymes called HDACs (histone deacetylases) that promote the growth of cancer cells. Reduced quantities of HDACs was recorded in the artemisinin-treated breast cancer cells.

The outcome of the study indicates that the well-known anti-malarial drug artemisinin bears a strong potential to be used as an anticancer agent. “Our findings provide rational insight for the further evaluation of artemisinin as a safe, efficient and selective drug in the treatment and prevention of human breast cancer”, conclude the authors of the study.