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Abstract Detail



Bryological and Lichenological Section/ABLS

Shrestha, Gajendra [1], Leavitt, Steven D. [2], St Clair, Larry [3], O'Neill, Kim L. [4].

Can we cure cancer with lichens?

Natural products from plants, fungi, and a variety of microorganisms have been of considerable value to the pharmaceutical industry over the past half-century. However, there still remains a vast reservoir of unexplored possibilities, including lichens with their more than 1000 different secondary chemicals. Despite the fact that lichens have many biological roles, the role of North American lichens as a potential source of natural products has been largely unexamined. To discover the anticancer role of selected lichens, we assessed cytotoxic activity of 17 species collected from various parts of the USA against Burkitt's Lymphoma cells (Raji). Based on cytotoxicity results, we then selected extracts of two species, Tuckermannopsis ciliaris and Xanthoparmelia chlorochroa and examined their mode of action. Secondary compounds of these 2 species were extracted with acetone. The IC50 values for T. ciliaris and X. chlorochroa were 24.1 and 21.8 µg/ml respectively. The viability and growth of Raji cells were significantly reduced by extracts from both species. We also performed morphological detection of apoptosis using Acridine orange and Propidium Iodide stains and biochemical detection using Annexin V. Both lichen extracts were found to induce apoptosis when treated with concentrations equivalent to IC50 of each extract. Proliferation of Raji cells, as measured by 3H-Thymidine Incorporation, was significantly reduced in treated cells (P <0.05) in 48 hours with X. chlorochroa as compared with the control. It was also found that both lichen extracts arrested cell-cycle progression in G1. Using RT-PCR, it was also found that the p53 gene was up-regulated in Raji cells treated with the X. chlorochroa extract while the DNA repair enzyme Thymidine kinase 1 (TK1 gene) was down regulated. In conclusion, extracts from both lichens could potentially be a source of anti-cancer drug therapies. However, additional research will be required to elucidate the molecular mechanisms behind these preliminary results.

Broader Impacts:


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1 - M L. Bean Life Science Museum, Biology, Brigham Young University, Provo, UT, 84602, USA
2 - M L. Bean Life Science Museum, Brigham Young University, Provo, UT, 84602, United States
3 - Brigham Young University, 193 MLBM, Provo, UT, 84602, USA
4 - Micro and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States

Keywords:
lichens
natural product
anticancer
cytotoxicity.

Presentation Type: Oral Paper:Papers for Sections
Session: 7
Location: Ascot/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 9:15 AM
Number: 7002
Abstract ID:339
Candidate for Awards:A. J. Sharp Award


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