Scientists Developing New Therapy for HER2-Positive Breast Cancer
• Uses HER2 as a target to selectively deliver toxins to cancer cells.
• Designed to overcome issues of resistance with Herceptin.
PHILADELPHIA — Patients with HER2-positive breast cancer may have an alternative therapy when they develop resistance to trastuzumab, also known as Herceptin, according to a laboratory finding published in Clinical Cancer Research, a journal of the American Association for Cancer Research.
Jacek Capala, Ph.D., D.Sc., an investigator at the National Cancer Institute, and colleagues designed, produced and tested HER2-Affitoxin, a novel protein that combines HER2-specific affibody molecules and a modified bacterial toxin, PE38.
“Unlike the current HER2-targeted therapeutics, such as Herceptin, this protein does not interfere with the HER2 signaling pathway but, instead, uses HER2 as a target to deliver a modified form of bacterial toxin specifically to the HER2-positive cancer cells. When cells absorb the toxin, it interferes with protein production and, thereby, kills them,” said Capala.
At least, that is what happened in Capala’s laboratory. After Affitoxin was injected into tumor-bearing mice, even relatively large, aggressive tumors stopped growing and most of them disappeared. The effect was strong enough that Capala believes it warrants a clinical trial.
“Herceptin has revolutionized the treatment of patients with HER2-positive breast cancer, but a significant number of tumors acquire resistance to the drug,” said Capala. “Affitoxin could offer another therapeutic option for those patients whose tumors no longer respond to Herceptin.”
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The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, the AACR is the world’s oldest and largest professional organization dedicated to advancing cancer research. The membership includes 33,000 basic, translational and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 90 other countries. The AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants, research fellowships and career development awards. The AACR Annual Meeting attracts more than 18,000 participants who share the latest discoveries and developments in the field. Special conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment and patient care. Including Cancer Discovery, the AACR publishes seven major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; Cancer Epidemiology, Biomarkers & Prevention; and Cancer Prevention Research. AACR journals represented 20 percent of the market share of total citations in 2009. The AACR also publishes CR, a magazine for cancer survivors and their families, patient advocates, physicians and scientists.