New Broccoli Compound Appears Promising Against Breast Cancer

In the future, a "broccoli-pill" a day may help keep breast cancer at bay. Researchers have developed a new compound, designed from a known anticancer agent found in broccoli, that shows promise as a breast cancer preventive.

Apparently less toxic than its natural counterpart, the compound could be marketed for cancer prevention, the researchers say. Their findings were described at the 224th national meeting of the American Chemical Society, the world's largest scientific society.

Tests in animals have shown encouraging results, but no human studies have been done. If tests confirm the findings, the compound could be developed into a once-a-day pill or vitamin component for cancer prevention and perhaps be on the market in seven to ten years, the researchers say.

"It may be easier to take a cancer-prevention pill once a day rather than rely on massive quantities of fruits and vegetables," says Jerry Kosmeder, Ph.D., research assistant professor at the University of Illinois at Chicago and an investigator in the study.

Called oxomate, the synthetic compound works like its natural counterpart, sulforaphane, which was recently identified as a cancer-preventive agent in broccoli and other cruciferous vegetables (such as cabbage and Brussels sprouts). Both compounds boost the body's production of phase II enzymes, which can detoxify cancer-causing chemicals and reduce cancer risk. But the natural broccoli compound, sulforaphane, can be toxic in high doses, warns Kosmeder. He cites laboratory studies in which the compound, above certain levels, killed cultured animal cells. It is also difficult and expensive to synthesize. These factors make sulforaphane a poor candidate for drug development, he said.

Kosmeder designed oxomate to be less toxic than its parent compound by removing the chemical components that appear to be responsible for this toxicity. In tests on cultured liver cells, oxomate was seven times less toxic than sulforaphane, the researcher said. The synthetic compound is also cheaper and easier to produce, he added.

In tests on female rats, those that were fed oxomate after exposure to cancer-inducing chemicals had up to a 50 percent reduction in the number of breast tumors compared to rats that did not receive the compound, said Kosmeder.

After the initial discovery of sulforaphane as a broccoli component (by researchers at Johns Hopkins University in Baltimore), consumers have been urged to eat more of the vegetable and its close relatives to obtain its cancer-fighting benefit. For those who don't like to eat the familiar green stalks and their bushy flowerets, consumers have a growing number of dietary options, including sprouts, teas and tablets made from natural concentrates.

Kosmeder believes that these variations present a dosing challenge, as not all broccoli-derived products contain the same amount of sulforaphane. This is due to variations in the vegetable's processing, growing conditions and strain, he said.

"Oxomate would give you a definitive benefit; you'd know exactly how much you're getting everyday, its exact benefit and risk," the researcher says.

Oxomate could be taken along with other cancer preventive agents, including nutrients and drugs, in an effort to maximize protection, he said.

Tamoxifen is currently the only FDA approved drug for breast cancer prevention in high-risk women. It works by a different mechanism from oxomate's. Tamoxifen helps a woman who has estrogen-dependent tumors, but may not help those with non-estrogen-dependent tumors, says Kosmeder. A drug based on oxomate would help prevent cancer formation regardless of whether the tumor is estrogen-dependent or non-estrogen-dependent, he says.

If subsequent tests for preventing other types of cancer prove effective, then oxomate might be useful for anyone who is at increased risk of cancer due to exposure to cancer-causing agents, according to Kosmeder. The drug would be particularly beneficial for those at highest risk, such as smokers, he says.

Consumers are still urged to continue eating healthful amounts of fruits and vegetables and to reduce their exposure to cancer risk factors, such as smoking, the researcher says.

Kosmeder conducted his oxomate studies as part of a research team headed by John M. Pezzuto, Ph.D., head of the department of medicinal chemistry and pharmacognosy at the university and deputy director of its Cancer Center.

The National Cancer Institute provided funding for this study.

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The poster on this research, MEDI 98, will be presented at 8 p.m., Sunday, Aug. 18, at the Hynes Convention Center, Hall B, during a general poster session and at 8:00 p.m., Monday, Aug. 19, at the Hynes Convention Center, Hall B during Sci-Mix.

Jerry Kosmeder, Ph.D., is a research assistant professor in department of medicinal chemistry and pharmacognosy at the University of Illinois at Chicago.

John M. Pezzuto, Ph.D., is head of the department of medicinal chemistry and pharmacognosy at the University of Illinois at Chicago. He is also deputy director of the university's Cancer Center.

-- Mark T. Sampson

EMBARGOED FOR RELEASE: Sunday, Aug. 18, 8:00 PM, Eastern Time

MEDI 98

Cancer chemopreventive activity of oxomate: A monofunctional inducer of phase II detoxification enzymes

Oxomate (1) is a synthetic analog of sulforamate (2) that induces phase II enzymes as measured by quinone reductase (QR) induction in mouse hepatoma (Hepa 1c1c7) cells. Oxomate and related analogs were shown to be monofunctional (no induction of phase I enzymes) by inducing QR in mutant Hepa 1c1c7 BPrC1 cells, which cannot activate the xenobiotic response element (XRE), as in the case with bifunctional inducers. Furthermore, oxomate and derivatives activated ARE, but not XRE, in human hepatoma (HepG2) cells stably transfected with a luciferase reporter gene under the control of either an ARE- or XRE-inducible promotors. Oxomate inhibits dimethylbenz(a)anthracene (DMBA)-induced lesions in mouse mammary organ culture and elevates QR, glutathione, and glutathione S-transferases in several target tissues of Sprague-Dawley rats. In female Sprague-Dawley rats challenged with DMBA, oxomate (1 and 3 g/kg diet) significantly reduced adenocarcinoma multiplicity. In summary, oxomate is a novel cancer chemopreventive agent with promise for the inhibition of mammary carcinogenesis. (Supported by P01 CA48112 awarded by NCI)

EMBARGOED FOR RELEASE: Sunday, Aug. 18, 8:00 PM, Eastern Time

MEDI 98

Cancer chemopreventive activity of oxomate: A monofunctional inducer of phase II detoxification enzymes

* Briefly explain in lay language what you have done, why it is significant and its implications, particularly to the general public.

Oxomate is a synthetic compound that increases detoxification enzymes in cells to protect against damage from carcinogens. Oxomate acts the same way as sulforaphane, a natural cancer preventive found in cruciferous vegetables (broccoli, cabbage, brussel sprouts, etc.), however, oxomate is less toxic and can be produced synthetically in large quantities, unlike sulforaphane.Oxomate prevents cancer cell formation in mouse breast tissue and carcinogen-treated rats fed oxomate develop fewer breast tumors than rats fed a regular diet. Oxomate holds the potential to prevent breast cancer by blocking carcinogens from turning normal cells into cancer cells. It is conceivable that oxomate or a similar drug could be given to individuals challenged by carcinogens (i.e. smokers) to reduce the risk of developing cancer.

* How new is this work and how does it differ from that of others who may be doing similar research?

Oxomate has never been synthesized nor tested previously, therefore this is a totally new and unknown compound. Oxomate is a synthetic derivative of sulforamate, previously synthesized by our research group. Sulforamate is an analog of sulforaphane, a natural cancer preventive agent found in cruciferous vegetables (broccoli, cabbage, brussel sprouts, etc.). Unfortunately, sulforaphane is toxic in high doses and it is difficult to produce both sulforaphane and sulforamate in large quantities. Oxomate has similar activity to sulforaphane and sulforamate, but is less toxic than either one and is much easier to produce in large amounts.