Can One tRNA Reverse Hormone Resistance in Prostate Cancer?

A new study published in Nature has identified a single transfer RNA, tRNA₁^Arg(UCU) as an important regulator of prostate cancer behaviour and resistance to hormone therapy.
The researchers found that this tRNA is relatively abundant in androgen receptor-driven prostate cancer, but falls as tumours become more aggressive, more plastic and more neuroendocrine-like. In samples from 56 patients, higher levels were linked to stronger androgen-receptor activity, while lower levels were associated with more aggressive disease.
The most interesting result came when the researchers changed the tRNA levels directly. Restoring tRNA₁^Arg(UCU)in resistant prostate cancer cells pushed them back towards a more hormone-dependent state and made them sensitive to enzalutamide again. Reducing the tRNA had the opposite effect. In an animal model, loss of the tRNA was linked to about a fourfold increase in metastases.
The mechanism appears to involve proteins that control gene activity and cell identity, including the SWI/SNF complex. This suggests that the tRNA may not simply mark aggressive disease, but may actually help control whether prostate cancer stays hormone-sensitive or becomes resistant.
Low levels of tRNA₁^Arg(UCU) were also linked to faster metastatic progression and worse survival, suggesting it could eventually be useful as a biomarker of treatment resistance.
The work is still preclinical. There is currently no treatment that can safely restore this tRNA inside prostate tumors in patients.

Still, the study raises an intriguing possibility: instead of only trying to kill resistant cancer cells, future therapies might be able to push them back into a state where existing hormone treatments work again.

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