This inexpensive oral drug could make cancer therapy more effective

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Scientists from Weill Cornell Medicine found that treatment with arginine, one of the amino-acid building blocks of proteins, enhanced the effectiveness of radiation therapy in cancer patients with brain metastases.

The research is published in Science Advances and was conducted by Dr. Leandro Cerchietti et al.

In the study, researchers reported results of administering arginine, which can be delivered in oral form, prior to standard radiation therapy in 31 patients who had brain metastases.

Nearly 78 percent had a complete or partial response in their brain tumors over the follow-up period of up to four years, while only 22 percent of the 32 patients who received a placebo prior to radiotherapy had such a response.

The trial was designed to gauge the effectiveness of arginine as a “radiosensitizer” that enhances the effects of radiation treatment.

However, the results, and arginine’s apparent mechanism of action, suggest that the amino acid might be useful more broadly as an anticancer therapy.

The team says based on these findings we should continue to investigate arginine in combination with radiotherapy but also in combination with chemotherapy or immunotherapy, and even arginine on its own.

Arginine, also called L-arginine, is inexpensive and widely available, generally considered safe, and can get relatively easily from the bloodstream into the brain.

The idea of using it to treat cancer arose from observations that tumors often aid their own survival by producing high levels of the related molecule nitric oxide (NO).

The latter regulates multiple processes in the body including the flow of blood through blood vessels, and tumors cells often make more NO by upregulating their production of special enzymes called NO synthases, which synthesize NO from arginine.

Reducing NO production is one possible way of exploiting tumors’ dependence on this molecule, but hasn’t worked well, in part because of adverse side effects.

The team found that boosting NO production instead—by adding its precursor arginine—might be beneficial, because while tumors can use NO to aid their growth and survival, they must keep its production below certain limits.

Overloading a high-NO tumor with much more NO prior to radiation treatment could weaken the tumor’s ability to repair radiation-induced DNA damage.

Evidence from this study and prior research also suggests that arginine can not only directly hobble tumor cells but also boost the activity of antitumor immune cells.

If you care about cancer, please read studies about inflammation drug that could help stop cancer metastasis, and what you need to know about supplements and cancer.

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