By incorporating PC-SPES into the rat diet, researchers conducting an in vivo study showed antitumor effects using a Dunning R3327 rat prostate cancer model. Levels of 0.05% and 0.025% of dietary PC-SPES were fed to the rats over a 6-week period. No toxicity was seen, nor was there a difference in the food intake of the rats during this time. Pulmonary tumors were induced by intradermal injections of MAT-LyLu cells, which are particularly resistant to many forms of treatment. Tumor incidence was inhibited in a dose-dependent manner, and the rate of tumor growth showed the same dose-dependent response. [1,2]

In another study, which used male BNX nu/nu immunodeficient nude mice, PC-SPES was also administered orally, but in suspension. The mice received 300 rad of whole-body irradiation, after which they were inoculated with either PC-3 or DU-145 prostate cancer cell lines. Treatment with PC-SPES began the day after injection. Results showed that PC-SPES suppressed the growth of DU-145 tumors compared to tumor growth in the control group. Cytological analysis showed apoptosis in the treated group that was not apparent in controls.[3]

In two other studies, clinical studies of patients were initiated along with in vitro and in vivo research. The results of these two patient groups are discussed in the Clinical Trials ¹ section. The first study, preceding more extensive research, examined in vitro activity of PC-SPES against LNCaP, LNCaP-bcl-2, PC-3, and DU-145 cells lines. Results showed that PC-SPES was active in suppressing both hormone -sensitive and -insensitive prostate cancer cell lines. In the subsequent study, research was conducted in vitro on the ability of PC-SPES to induce apoptosis in androgen-independent (AI) prostate cancer cell lines, and in vivo on the effect of oral PC-SPES on the growth of xenographed PC-3 tumors in immunodeficient male mice. Mice in the treatment arm—in which treatment was started 1 week after implantation—showed a significant decrease in tumor weight when compared with mice in the control arm. PC-SPES showed activity against both androgen -sensitive and AI prostate cancer in the patients and suppressed tumor growth in AI tumors in mice. Reviewed in [3-5] In both studies, the patients were given capsules manufactured between 1996 and 1999, a time when contamination levels of DES were highest.[6]

Another study in rats demonstrated that PC-SPES (one lot contaminated with DES and one lot without DES) causes some decrease in the activity of a liver enzyme involved in drug metabolism (CYP3A).[7]

References

1. Tiwari RK, Geliebter J, Garikapaty VP, et al.: Anti-tumor effects of PC-SPES, an herbal formulation in prostate cancer. Int J Oncol 14 (4): 713-9, 1999.  [PUBMED Abstract]
   
   
2. Geliebter J, Mittelman A, Tiwari RK: PC-SPES and prostate cancer. J Nutr 131 (1): 164S-166S, 2001.  [PUBMED Abstract]
   
   
3. de la Taille A, Buttyan R, Hayek O, et al.: Herbal therapy PC-SPES: in vitro effects and evaluation of its efficacy in 69 patients with prostate cancer. J Urol 164 (4): 1229-34, 2000.  [PUBMED Abstract]
   
   
4. Pirani JF: The effects of phytotherapeutic agents on prostate cancer: an overview of recent clinical trials of PC SPES. Urology 58 (2 Suppl 1): 36-8, 2001.  [PUBMED Abstract]
   
   
5. de la Taille A, Hayek OR, Buttyan R, et al.: Effects of a phytotherapeutic agent, PC-SPES, on prostate cancer: a preliminary investigation on human cell lines and patients. BJU Int 84 (7): 845-50, 1999.  [PUBMED Abstract]
   
   
6. Sovak M, Seligson AL, Konas M, et al.: Herbal composition PC-SPES for management of prostate cancer: identification of active principles. J Natl Cancer Inst 94 (17): 1275-81, 2002.  [PUBMED Abstract]
   
   
7. Wadsworth T, Poonyagariyagorn H, Sullivan E, et al.: In vivo effect of PC-SPES on prostate growth and hepatic CYP3A expression in rats. J Pharmacol Exp Ther 306 (1): 187-94, 2003.  [PUBMED Abstract]
   
   

Glossary Terms

A process in which anything complex is separated into simple or less complex parts.

A type of hormone that promotes the development and maintenance of male sex characteristics.

Describes the ability of tumor cells to grow in the absence of androgens (hormones that promote the development and maintenance of male sex characteristics). Many early prostate cancers require androgens for growth, but advanced prostate cancers are often androgen-independent.

A type of cell death in which a series of molecular steps in a cell leads to its death. This is the body’s normal way of getting rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Also called programmed cell death.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called a clinical trial.

In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

Cells of a single type (human, animal, or plant) that have been adapted to grow continuously in the laboratory and are used in research.

Diethylstilbestrol. A synthetic form of the hormone estrogen that was prescribed to pregnant women between about 1940 and 1971 because it was thought to prevent miscarriages. DES may increase the risk of uterine, ovarian, or breast cancer in women who took it. It also has been linked to an increased risk of clear cell carcinoma of the vagina or cervix in daughters exposed to DES before birth. Also called diethylstilbestrol.

The things a person eats and drinks.

Refers to the effects of treatment with a drug. If the effects change when the dose of the drug is changed, the effects are said to be dose-dependent.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

A cell line made from human prostate cancer cells that is used in the laboratory to study the way prostate cancer cells grow.

A protein that speeds up chemical reactions in the body.

One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.

The decreased ability of the body to fight infections and other diseases.

In the laboratory (outside the body). The opposite of in vivo (in the body).

In the body. The opposite of in vitro (outside the body or in the laboratory).

The number of new cases of a disease diagnosed each year.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

Within the skin. Also called intracutaneous.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

The total of all chemical changes that take place in a cell or an organism. These changes make energy and the materials needed for growth, reproduction, and maintaining health. They also help get rid of toxic substances.

By or having to do with the mouth.

A mixture of eight herbs that has been sold as a dietary supplement and promoted as a way to keep the prostate healthy and to treat prostate cancer. PC-SPES has been studied in the treatment of prostate cancer, but has been taken off the market in the U.S. because of safety concerns.

A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.

Having to do with the lungs.

Cancer that does not respond to treatment. The cancer may be resistant at the beginning of treatment, or it may become resistant during treatment. Also called refractory cancer.

In medicine, an improvement related to treatment.

In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant.

Radiation therapy to the entire body. It is usually followed by bone marrow or peripheral stem cell transplantation.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.