A protein in HDL, the carrier of so-called “good” cholesterol that already is in use to fight heart disease, has now been shown to help prime your immune system to fight certain types of cancer.
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Stanley Hazen, MD, PhD, section head of Preventive Cardiology at Cleveland Clinic’s Heart and Vascular Institute and chair of Cellular & Molecular Medicine at the Lerner Research Institute, led the study that discovered the protein’s anti-tumorigenic effect. Results of the study could lead to new, powerful anti-cancer drugs.
HDL’s important health benefits
HDL helps protect you against narrowing and hardening of the arteries. A major component in HDL, a protein called apolipoprotein A1 (apoA1), is specifically known to deter atherosclerosis, and drugs that boost apoA1 are already in use in preventative cardiology. Clinical trials have also shown direct infusion of the protein apoA1 into subjects can serve as a “liquid Drano” for atherosclerotic vessels, promoting regression of artery wall plaques. Consequently, several companies are pursuing apoA1 as a therapy for heart disease.
Intrigued by apoA1’s power as a cardioprotective agent, Dr. Hazen and his team delved further into how apoA1 promotes its beneficial effects. Along the way, they discovered it has tremendous potential as a potent anti-cancer agent.
Hazen’s study focused on apoA1 in mice, specifically the ability of apoA1 to prime the immune system to fight off cancer. As model systems, they examined malignant melanoma, a leading and growing cause of cancer in young adults, and lung cancer.
The research showed that mice that had the apoA1 protein were more resistant to tumor growth and survived longer than their apoA1-lacking counterparts. More importantly, results show that direct injection of apoA1 as a therapy into mice with existing tumors and metastases not only inhibited the growth of tumors and the spread of malignant melanoma and lung cancer, but promoted regression of existing tumors and metastases.
Like a stealth fighter, apoA1 acts indirectly to fight cancer. It alters the immune system, creating an unfavorable environment for tumor growth. It actually alters the actions of certain types of white blood cells (key players in the immune system) from pro-tumor to anti-tumor.
The beauty of the findings is that this protein turns on the ignition in the immune system’s engine and directs it to attack and inhibit the progression of the disease.
Results and hope for the future
The results are definitive; apoA1 increased survival rates and suppressed the spread of malignant melanoma and lung cancer in laboratory mice. Physicians already prescribe drugs that mildly boost apoA1 to treat cardiovascular disease. The results of Dr. Hazen’s work suggest that there is promise for the development of apoA1-targeted therapies, including possibly direct infusion of apoA1 itself in the fight against various types of cancer.
Dr. Hazen sums up the potential benefits to cancer patients. “This is another example of where research in one field can yield exciting new discoveries that could benefit an entirely new pool of patients.”