Research In Brief: Article Shows That Plant Hormones May Inhibit Various Cancers

APRIL 28, 2014 – Plant hormones, which have been shown to potentially inhibit growth of breast cancer cells and stem cells, may also work on other types of cancer cells, according to new research out of the School of Nursing & Health Studies (NHS).

The findings were reported in the article, “Strigolactone Analogues Induce Apoptosis Through Activation of p38 and the Stress Response Pathway in Cancer Cell Lines and in Conditionally Reprogrammed Primary Prostate Cancer Cells,” which appeared in the journal Oncotarget.

Ronit I. Yarden (G’96), PhD, assistant professor of human science at NHS, is corresponding author, and Claire B. Pollock, PhD, a member of Yarden’s research team, is lead author.

Targeting Cancer Cells

“Strigolactones are a novel class of plant hormones produced in roots and regulate shoot and root development,” the authors say.  “We have previously shown that synthetic strigolactone analogues potently inhibit growth of breast cancer cells and breast cancer stem cells.”

The new study reveals that these analogues may inhibit growth and survival of “an array of cancer-derived cell lines representing solid and non-solid cancer cells.”  They represent prostate, colon, lung, melanoma, osteosarcoma, and leukemic cell lines.

Meanwhile, normal cells were minimally affected during the experiments, the authors note.

“Strigolactone analogues are promising candidates for anticancer therapy by their ability to specifically induce cell cycle arrest, cellular stress, and apoptosis in tumor cells with minimal effects on growth and survival of normal cells,” the say.

Reprogrammed Cells

Yarden says that an exciting part of the experiment involved the use of conditionally reprogrammed cells, a technology developed by Richard Schlegel, MD, PhD, chair of the Department of Pathology at Georgetown Lombardi Comprehensive Cancer Center.

“The technique enables researchers to take tumor cells and normal cells of the same tissue from the same patient and grow them indefinitely,” says Yarden, who mentored the undergraduate students during the research study.  “We used prostate tumor and normal cells from the same patient to test our potential drug.  Only the prostate tumor cells of the patient were killed by the strigolactone analogues, but the normal prostate cells of the same patient were not affected by strigolactones.”

Authors and Support

Other authors represent Georgetown University Medical Center in Washington, the University of Turin in Italy, Massachusetts General Hospital in Boston, and the Agricultural Research Organization in Israel.

They are Schlegel, Sara McDonough (NHS’12), Victor S. Wang (NHS’15), Hyojoung Lee (NHS’11, G’12), Lymor Ringer (G’12), PhD, Xin Li, PhD, Christina Prandi, PhD, Richard J. Lee, MD, PhD, Adam S. Feldman, MD, MPH, Hinanit Koltai, PhD, Yoram Kapulnik, PhD, Olga Rodriguez, MD, and Christopher Albanese, PhD.

This work was supported by the Department of Defense (DOD) Breast Program (W81XWH-11-1-0190), the BioBits Project in Italy, the University of Turin in Italy, a DOD pre-doctoral grant (PC101946), a National Cancer Institute grant (R01 CA129003), a DOD Prostate Cancer Research Program Synergistic Idea Development Award (W81XWH-13-1-0327), and a CTSA pilot award through the Georgetown-Howard Universities Center for Clinical and Translational Science.

Patent Applications

Georgetown and the Agricultural Research Organization have submitted patent applications for the strigolactone technology described, on which Yarden, Koltai, Kapulnik, and Prandi are inventors.

Georgetown University has filed a patent application for the cell reprogramming technology described, on which Schlegel is an inventor.  In addition, Georgetown has licensed the technology to an outside entity for commercialization.

By Bill Cessato