Marijuana May Yield Cancer-Fighting Drugs

September 13, 2004

Miranda Hitti, WebMD

Sept. 14, 2004 -- Marijuana's active ingredient may form the basis for new antiviral drugs that fight cancer-causing herpes viruses.

Professor Peter Medveczky, MD, of the University of South Florida's medical microbiology and immunology department, and H. Lee Moffitt Cancer Center & Research Institute in Tampa, and colleagues worked on the study.

Their report appears in the Sept. 15 issue of the journal BMC Medicine.

Key Ingredient

The researchers focused on marijuana's active ingredient, delta-9-tetrahydrocannibol (THC).

In tissue culture tests, THC blocked the reactivation of various types of herpes viruses. Infection with herpes virus is recurrent and lifelong. The virus lies dormant in nerve tissue in infected people after symptoms have gone away. Later the virus can reactivate itself leading to an increasing number of viruses and causing another symptomatic infection.

In the study, researchers tested THC against various herpes viruses including Kaposi's sarcoma-associated herpes virus (KSHV) and Epstein-Barr virus.

Kaposi's sarcoma, prevalent among people with AIDS and a common form of cancer in Africa, stems from KSHV.

Cancers of cells from the immune system such as Burkitt's lymphoma and Hodgkin's disease are associated with Epstein-Barr virus, a member of the herpes virus family.

In the presence of THC, cells infected with the viruses couldn't reactivate.

THC may interfere with a gene called ORF50, which is found in these herpes viruses, say the researchers. This gene helps turn on the virus's machinery that is involved with reactivating the virus; it also helps start viral replication.

Not a Fix for Herpes

The researchers also tested THC on herpes simplex-1, which causes cold sores.

It didn't work.

THC appears to specifically work against herpes viruses that cause these tumors -- gamma herpes viruses.

New Drugs Ahead?

The findings may lead to the development of new drugs that thwart cancer-causing herpes viruses from reactivating, say the researchers.

Any new antiviral drugs based on THC would not have marijuana's psychoactive effects.

The next step is testing THC's benefits on lab animals.

No Pot Prescription

According to a news release, Medveczky says that since THC can suppress the immune system, smoking marijuana might do more harm than good to patients infected with these viruses who often have weakened immune systems.

'Our findings do not recommend that people take pot to prevent or treat cancers associated with gamma herpes viruses,' says Medveczky in the news release.



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