Chapter 1: The Enigma of APOBEC3A

The immune enzyme known as APOBEC3A exhibits a paradoxical nature, akin to the character in Robert Louis Stevenson’s 1886 tale, "Strange Case of Dr. Jekyll and Mr. Hyde." By day, the enzyme protects healthy cells from viral threats, yet by night, it can spur dangerous mutations in cancer cells that lead to metastasis and resistance to treatment.

In recent research conducted by molecular immunologists at the University of California, Irvine, the complex behavior of APOBEC3A has been further elucidated. The team uncovered two separate pathways that regulate the expression of this enzyme.

Previously, the researchers had shown that mutations in DNA, instigated by APOBEC3A, are notably prevalent, found in more than 80 percent of lung and breast cancer cases. This highlights the enzyme’s significant impact on cancer cell genomes as it attempts to halt their proliferation.

In their latest findings, the scientists explored how viral infections and the stress from chemotherapy drugs affect APOBEC3A's functionality. They discovered that viral infections activate certain immune response pathways that enhance APOBEC3A’s activity, effectively eradicating viral invaders. Conversely, chemotherapy triggers a different immune response, prompting APOBEC3A to induce mutations in cancer cells, which can lead to more aggressive tumor behavior.

“Understanding how cancer cells and viral infections modulate APOBEC3A expression positions us to make significant advances in developing new therapies for both cancer and viral infections,” stated Rémi Buisson, the lead investigator on the study.

Looking ahead, Buisson and his team intend to investigate APOBEC3A’s role in combating SARS-CoV-2, the virus responsible for COVID-19, and aim to devise strategies to prevent mutations in tumors induced by APOBEC3A, thereby enhancing the effectiveness of cancer treatments.

The first video, "Infecting Cancer: How Viruses Are Turning the Tide Against Tumors, w Dr. John Bell," delves into how viruses can be harnessed to target cancer cells, presenting a revolutionary perspective on treatment.

The second video, "Killing Cancer With Viruses: Patrick Lee at TEDxHalifax," discusses innovative approaches to cancer therapy using viral agents, illustrating the potential of combining immunology with oncology.

Sources: Nature Communications, UCI School of Medicine.