International Edition
Latest News
Health

Vitamin A & Cancer: Immune System Connection

Summary of the Research on ALDH1a2/a3, Retinoic Acid, and Cancer Immunotherapy: This research details a newly discovered mechanism explaining why many cancer vaccines, particularly dendritic cell (DC) vaccines, have shown limited success in clinical trials. Here's a breakdown…

Vitamin A & Cancer: Immune System Connection

Summary of the Research on ALDH1a2/a3, Retinoic Acid, and Cancer Immunotherapy:

This research details a newly discovered mechanism explaining why many cancer vaccines, particularly dendritic cell (DC) vaccines, have shown limited success in clinical trials. Here’s a breakdown of the key findings:

The Problem:

* ALDH1a2 & Retinoic Acid Suppression: During the process of creating DC vaccines, differentiating dendritic cells start producing high levels of retinoic acid (a vitamin A metabolite) due to increased expression of the ALDH1a2 enzyme. This retinoic acid suppresses DC maturation, hindering their ability to effectively trigger an anti-tumor immune response.
* Macrophage Shift: Retinoic acid also promotes the formation of less effective macrophages, replacing functional DCs and further weakening the vaccine’s impact.
* Vitamin A Paradox: While retinoic acid in vitro can inhibit cancer cell growth, high vitamin A intake in vivo is linked to increased cancer risk and mortality. This is as cancer cells exploit retinoic acid to suppress the immune system.

The Discovery & solution:

* ALDH1a2/a3 as Drug Targets: Researchers successfully developed inhibitors (like KyA33) that target ALDH1a2 and ALDH1a3, enzymes responsible for retinoic acid production. This is a significant breakthrough as the retinoic acid pathway was the first nuclear receptor signaling pathway discovered but previously untreatable with drugs.
* Restoring Immune Function: Blocking ALDH1a2/a3 restores DC maturation and their ability to activate immune defenses. KyA33, when used with DC vaccines, generated strong anti-tumor immune responses in mice, delaying tumor development and slowing progression.
* Self-reliant Immunotherapy: KyA33 also showed promise as a standalone immunotherapy, reducing tumor growth by stimulating the immune system.
* Immune Habitat Focus: The research clarifies that retinoic acid primarily impacts the immune environment around tumors, suppressing T cell activity, rather than directly affecting the cancer cells themselves.

Implications & Future Directions:

* New Cancer Therapies: These findings pave the way for a novel therapeutic approach to cancer by targeting the retinoic acid pathway.
* Kayothera Biotech: The researchers have launched a biotechnology company, Kayothera, to advance ALDH1A inhibitors into clinical trials.
* Broader Applications: the potential extends beyond cancer to other diseases influenced by retinoic acid, including diabetes and cardiovascular disease.

In essence,this research identifies a key mechanism by which cancer evades the immune system and offers a promising new strategy for immunotherapy by blocking the production of immune-suppressing retinoic acid.

Worth a look

About the author: Dr Natalie Singh - Health Editor

Board‑certified internal‑medicine physician and MPH. Natalie authored peer‑reviewed studies on infectious disease and served as medical editor. “Dr. Natalie Singh delivers evidence‑based health news, medical breakthroughs, and expert wellness guidance.”