Before the discovery of diethylsylbestrol (DES), warfarin, and indomethacin contamination, PC-SPES appeared to have some efficacy as an antineoplastic agent in laboratory and animal studies. These studies are presented below. Due to the fact that there was no standardization of the composition of PC-SPES or any knowledge of the amount of contamination of each lot used in testing, it is difficult to interpret the data from these studies.

In one study that attempted to measure the effects of the whole PC-SPES mixture versus that of individual herbs of PC-SPES on prostate-specific antigen (PSA) expression and cell growth, LNCaP cells were treated with ethanol extracts of PC-SPES and each of the eight herbs. The PC-SPES mixture reduced cell growth by 72% to 80%, while Dendranthema morifolium (Ramat.) Tzvelev (synonym Chrysanthemum morifolium) (chrysanthemum) produced the highest reduction of the herb group at 85%. Panax pseudo ginseng var. notoginseng Hoo & tseng (Synonym Panax notoginseng [Burkill] F.H.Chen) was next at 80.9% reduction, followed by Glycyrrhiza uralensis Fisch ex DC.(73%). The lowest reduction in cell growth was exhibited by Serenoa repens (Bartr.) Small (14.5%). Scutellaria baicalensis Georgi, Serenoa repens, and Glycyrrhiza uralensis lowered PSA expression, but each of the other herbs increased PSA expression. The ability of individual herbs to reduce PSA expression was not uniform, but the PC-SPES mixture as a whole exhibited a uniform response. The varying results with the individual herbs and the positive response of the cells (i.e., increased cytotoxicity and reduced PSA expression) to the aggregate PC-SPES mixture may suggest that the botanicals in PC-SPES work in concert and that no individual herb can account for the overall effects of the mixture.[1]

In other studies, PC-SPES was found to inhibit clonal growth in three human prostate cancer cell lines: LNCaP, PC-3, and DU-145. Cell cycle analysis showed cell cycle arrest at the G2 phase.[2] Cell proliferation and reduced clonogenicity were observed in cancer cell lines other than those of prostate cancer: human breast carcinoma lines MCF-7 and T47-D, SK-N-MC neuroepithelioma, COLO 38 melanoma, U937 histiomonocytic lymphoma, and HL-60 and MOLT-4 leukemias. Cytotoxic and cytostatic effects of PC-SPES were common to all tumor cell lines tested.[3]

In another study evaluating regulation of PSA expression and androgen receptor (AR) activity, LNCaP prostate cancer cell lines showed downregulation of both proliferating cell nuclear antigen (PCNA) and PSA expression. PSA changes occurred concurrently with the decrease of PCNA. The results suggest that PC-SPES modulates cell growth by changing PCNA expression and may decrease PSA levels indirectly by suppressing AR expression.[4]

None of the studies above indicated lot number or year of manufacture of the PC-SPES used. Therefore, it is not possible to assess the amount of contamination of the mixtures used in the studies or whether the mixtures used were not in fact contaminated.

A 1998 study that evaluated estrogenic activity of extracts of PC-SPES, ginseng (Panax ginseng C.A. Meyer), saw palmetto, DES, and estrone (estradiol -17 beta) in vitro reported on the estrogenic response of ovariectomized CD-1 mice to PC-SPES extract as well as the response to PC-SPES capsules in eight prostate cancer patients who had received previous therapy. [5] This study used four samples of PC-SPES ordered in separate purchases from BotanicLab. No lot numbers were supplied in the study. Lot numbers from October 1996 through July 1998 were later tested for contamination and had DES levels of 114.74 μg/g to 159.27 μg/g, as well as the highest detected levels of indomethacin of the PC-SPES lots tested.[6] In vitro tests of PC-SPES extract or estradiol showed estrogenic activity similar to 1 nM estradiol on estrogen receptor Y253 yeast strain. Transcriptional activation assays in yeast strain PL3 Saccharomyces cerevisiae with ethanolic extract of PC-SPES exhibited estrogen-like effects. In the eight prostate cancer patients, serum testosterone concentrations decreased during the use of PC-SPES and increased within 3 weeks after treatment was discontinued. PSA levels decreased in all eight patients. Side effects in all eight patients were similar to those seen after treatment with estrogen: breast tenderness and loss of libido. One patient had superficial venous thrombosis.

References

1. Hsieh TC, Lu X, Chea J, et al.: Prevention and management of prostate cancer using PC-SPES: a scientific perspective. J Nutr 132 (11 Suppl): 3513S-3517S, 2002.  [PUBMED Abstract]
   
   
2. Kubota T, Hisatake J, Hisatake Y, et al.: PC-SPES: a unique inhibitor of proliferation of prostate cancer cells in vitro and in vivo . Prostate 42 (3): 163-71, 2000.  [PUBMED Abstract]
   
   
3. Ko R, Wilson RD, Loscutoff S: PC-SPES. Urology 61 (6): 1292, 2003.  [PUBMED Abstract]
   
   
4. Hsieh TC, Wu JM: Mechanism of action of herbal supplement PC-SPES: elucidation of effects of individual herbs of PC-SPES on proliferation and prostate specific gene expression in androgen-dependent LNCaP cells. Int J Oncol 20 (3): 583-8, 2002.  [PUBMED Abstract]
   
   
5. DiPaola RS, Zhang H, Lambert GH, et al.: Clinical and biologic activity of an estrogenic herbal combination (PC-SPES) in prostate cancer. N Engl J Med 339 (12): 785-91, 1998.  [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]
   
   

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.

Any substance that causes the body to make a specific immune response.

Blocking the formation of neoplasms (growths that may become cancer).

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a 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. Also called malignancy.

Cancer that begins in the skin or in tissues that line or cover internal organs.

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

An increase in the number of cells as a result of cell growth and cell division.

A treatment that is given at the same time as another.

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

Cell-killing.

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

Effectiveness. In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.

A form of the hormone estrogen.

A protein found inside the cells of the female reproductive tissue, some other types of tissue, and some cancer cells. The hormone estrogen will bind to the receptors inside the cells and may cause the cells to grow. Also called ER.

In medicine, a preparation of a substance obtained from plants, animals, or bacteria and used as a drug or in drugs.

An herb with a root that has been used in some cultures to treat certain medical problems. It may have anticancer effects.

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

A drug that reduces pain, fever, swelling, and redness. It is also being used to reduce tumor-induced suppression of the immune system and to increase the effectiveness of anticancer drugs. It is a type of nonsteroidal anti-inflammatory drug (NSAID).

Research done in a laboratory. These studies may use test tubes or animals to find out if a drug, procedure, or treatment is likely to be useful. Laboratory studies take place before any testing is done in humans.

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.

Closely monitoring a patient's condition but withholding treatment until symptoms appear or change. Also called active surveillance, expectant management, and watchful waiting.

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.

Multiplying or increasing in number. In biology, cell proliferation occurs by a process known as cell division.

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.

A protein made by the prostate gland and found in the blood. Prostate-specific antigen blood levels may be higher than normal in men who have prostate cancer, benign prostatic hyperplasia (BPH), or infection or inflammation of the prostate gland. Also called PSA.

A protein made by the prostate gland and found in the blood. PSA blood levels may be higher than normal in men who have prostate cancer, benign prostatic hyperplasia (BPH), or infection or inflammation of the prostate gland. Also called prostate-specific antigen.

A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific physiologic effect in the cell.

In medicine, an improvement related to treatment.

The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

A hormone made mainly in the testes (part of the male reproductive system). It is needed to develop and maintain male sex characteristics, such as facial hair, deep voice, and muscle growth. Testosterone may also be made in the laboratory and is used to treat certain medical conditions.

Treatment.

The formation or presence of a thrombus (blood clot) inside a blood vessel.

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 cancer), or malignant (cancer). Also called neoplasm.

A drug that prevents blood from clotting. It belongs to the family of drugs called anticoagulants (blood thinners).