An experimental drug, RK-33, has demonstrated the ability to eliminate bone metastases caused by breast cancer in laboratory models, according to a new study led by Johns Hopkins Medicine researchers. The findings, published in Cancer Letters, suggest RK-33 could offer a novel treatment approach for breast cancer patients with bone metastasis, who currently have limited therapeutic options.
The study builds on previous work showing RK-33's effectiveness against other cancers and viral illnesses. Researchers focused on bone metastasis due to the challenges in treating cancer cells within the bone microenvironment, which often resists conventional therapies. Breast cancer with bone metastasis is often incurable, with treatments primarily focused on palliative care.
Targeting DDX3 in Bone Metastasis
The research team, led by Venu Raman, Ph.D., identified that the DDX3 protein is highly expressed in patient samples of breast cancer bone metastasis. DDX3, an RNA helicase, plays a crucial role in tumor cell growth and proliferation by unwinding RNA and facilitating the translation of genetic code into proteins. By targeting DDX3, RK-33 can disrupt these functions and slow cancer progression.
"One of our main queries was whether RK-33 could be effective for treating bone metastasis, based on previous lab findings that showed its effectiveness in suppressing breast cancer growth," said Raman, professor of radiology and radiological science and pharmacology at the Johns Hopkins University School of Medicine.
Preclinical Efficacy
In mice with breast cancer bone metastasis, treatment with RK-33 eliminated all evidence of bone metastases, as confirmed by imaging. The drug also prevented cancer cells in the bone from spreading to other organ systems, a common occurrence in bone metastasis. These results indicate that RK-33 can effectively target, halt the growth of, and fully eliminate breast cancer bone metastasis cells by inhibiting DDX3 and penetrating bone microenvironments.
Furthermore, RK-33 showed promise in preventing breast cancer bone metastasis from occurring in the first place. Mice with breast cancer that had not spread to bone received the drug, and researchers observed that the cancer never developed into bone metastases. No significant adverse reactions to RK-33 were observed in these experiments.
Future Directions
The researchers are optimistic about the potential of RK-33 and are moving closer to clinical trials. They plan to further investigate the drug's ability to treat other conditions and DDX3's role in other diseases. "We have demonstrated DDX3's involvement in aggressive cancers and how RK-33 represents a significant advancement in utilizing targeted therapies for cancers that currently lack specific treatments," Raman noted.
