Photosensitizer Enhances Cancer-Killing Ability Of Malaria Drug

By combining the anti-malarial drug artemisinin with a photosensitizer, researchers from Singapore have multiplied its cancer-killing ability ten-fold.

AsianScientist (Sep. 28, 2017) – In a study published in ACS Central Science, scientists in Singapore have showed that a combination of an anti-malarial drug and a photosensitizer can be used to treat colorectal cancer.

The potent anti-malarial drug, artemisinin, is activated by heme, an iron-containing compound found in hemoglobin and many metabolic pathway enzymes. When malarial parasites digest hemoglobin, large amounts of heme are released, leading to the activation of artemisinin which attacks multiple proteins essential for the malarial parasites’ survival. In recent years, artemisinin has gained attention as a promising alternative cancer treatment.

In this study, scientists from the National University of Singapore (NUS) showed that the anti-cancer properties of artemisinin could be enhanced by ten times when used in combination with aminolaevulinic acid (ALA), a photosensitizer, or a drug which generates toxic free radicals upon exposure to light.

“Artemisinin and ALA are both existing drugs that are well tolerated by the human body. As such, this promising cancer treatment could have fewer side effects,” explained Dr. Wang Jigang of the NUS Yong Loo Lin School of Medicine who is a co-author of the study.

The researchers discovered that a combination of artemisinin and ALA could kill colorectal cancer cells and suppress tumor growth more effectively than administering artemisinin alone. They also demonstrated that cancer cells had higher heme levels as compared to normal cells.

This is likely because cancer cells have higher rates of metabolism, and many metabolic pathway enzymes require heme for their activities. Upon activation by heme in cancer cells, artemisinin attacks more than 300 proteins, many of which are important for the survival of cancer cells.

“Having developed a better understanding of the anti-cancer activity of artemisinin in colorectal cancer, we will also be testing this combination treatment on other cancer types, such as liver cancer,” said Professor Shen Han-Ming from the Department of Physiology at NUS Yong Loo Lin School of Medicine.

The article can be found at: Wang et al. (2017) Mechanistic Investigation of the Specific Anticancer Property of Artemisinin and Its Combination with Aminolevulinic Acid for Enhanced Anticolorectal Cancer Activity.


Source: National University of Singapore; Photo: Shutterstock.
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