The cancer therapeutic agent tamoxifen improves contractile function and delays premature cell death in Duchenne muscular dystrophy (DMD) cardiomyocytes, a new study published in npj Regenerative Medicine found.

“Our study highlights the utility of a bioengineered [induced pluripotent stem cells] platform for drug testing and underscores the potential of repurposing tamoxifen as a therapy for DMD cardiomyopathy,” the authors said.

Heart failure secondary to dilated cardiomyopathy is one of the main causes of death in patients with DMD. Although drugs like angiotensin-converting enzyme inhibitors, beta-blockers, and mineralocorticoid receptor antagonists can be used to treat dilated cardiomyopathy in patients with DMD, they do not cure the cardiomyopathy.


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Research has shown that tamoxifen could improve cardiomyopathy in DMD, however, the exact mechanism of action is not well understood. Here, a team of researchers led by Helen M. Blau, PhD, examined the effects of 4-hydroxytamoxifen, the active metabolite of tamoxifen, on cardiac function. To do so, they used human-induced pluripotent stem cell-derived cardiomyocytes and a bioengineered platform to model DMD.

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They found that treating the DMD cardiomyocytes with 4-hydroxytamoxifen decreased beating rate, increased beating velocity, and improved calcium-handling deficits, thereby resulting in prolonged viability.

They concluded that repurposing tamoxifen for the treatment of cardiomyopathy in patients with DMD may therefore be beneficial. Because preclinical toxicological studies have already been conducted, repurposing existing drugs significantly lowers the entry barrier to clinical trials.

“These findings underscore the utility of performing a clinical trial in a dish,” they concluded.

Tamoxifen is a selective estrogen receptor modulator approved by the US Food and Drug Administration to prevent and treat breast cancer. It works by targeting the estrogen receptor alpha present in both skeletal muscle and the heart.

Reference

Birnbaum F, Eguchi A, Pardon G, Chang ACY, Blau HM. Tamoxifen treatment ameliorates contractile dysfunction of Duchenne muscular dystrophy stem cell-derived cardiomyocytes on bioengineered substrates. npj Regen Med. 2022;7(1):19. doi:10.1038/s41536-022-00214-x