Carnosine and Anti-cancer Activity

The anti-tumor properties of Carnosine were recognized more than three decades ago. Carnosine limits DNA damage that can transform healthy cells into cancerous cells. Carnosine inhibits tumor growth and helps prevent the spreading of existing cancers (metastasis) to healthy tissue.

Carnosine lowers ATP levels in cancer cells, thereby depriving them of the energy they need to develop.

In recent years considerable attention has been given to the use of natural substances as anticancer drugs. The natural antioxidant dipeptide L-carnosine belongs to this class of molecules because it has been proved to have a significant anticancer activity both in vitro and in vivo. Previous studies have shown that L-carnosine inhibits the proliferation of human colorectal carcinoma cells by affecting the ATP and Reactive Oxygen Species (ROS) production.

By inhibiting MMP-9 gene expression, Carnosine was able to stop the spreading of liver cancer cells.

Carnosine decreases AGEs, which are commonly implicated in cancer.

Carnosine increases the efficacy of chemotherapeutic drugs, like 5-FU.

By reducing mitochondrial oxidative stress, Carnosine slows the aging of cells that leads to ovarian cancer.

Cancer cells exposed directly to Carnosine showed less ability to thrive or proliferate and increased frequency of death.

Anti-neoplastic effects of carnosine were first described by Nagai and Suda (1986). These authors subcutaneously implanted Sarcoma-180 tumour cells into ddY mice. The day after implantation, carnosine was administered subcutaneously 2 cm from the implantation site. Treatment with carnosine (50 mg/kg/day) was continued every second day. When compared to treatment with saline, it became obvious that carnosine significantly inhibited tumour growth and also reduced mortality. Unfortunately, the experiments of Nagai and Suda did not receive their deserved attention, probably because the original manuscript was not published in English. Inspired by the work of Holliday and McFarland (1996) who found that carnosine selectively inhibited the growth of transformed and neoplastic cells, but over 20 years after the Nagai and Suda paper, Renner et al. (2008) showed that carnosine inhibited the growth of cultured tumour cells isolated from human glioblastoma.

It is anticipated that carnosine would not have severe negative side effects, and that beneficial effects for patients treated for certain types of cancers are likely. One example is carnosine-mediated protection from lung injury caused by radiation (Guney et al. 2006). In general, ionizing radiation is still a highly effective therapeutic tool for different types of cancer and is, therefore, frequently employed. Since formation of ROS is one of the major reasons for cellular injury after radiation (Riley 1994), carnosine may protect healthy tissue from damage and inflammation due to its antioxidant and anti-inflammatory properties.