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Open Access Research article

Anti-proliferative effect of methanolic extract of Gracilaria tenuistipitata on oral cancer cells involves apoptosis, DNA damage, and oxidative stress

Chi-Chen Yeh1, Jing-Iong Yang2, Jin-Ching Lee3, Chao-Neng Tseng14, Ya-Ching Chan4, You-Cheng Hseu5, Jen-Yang Tang67, Li-Yeh Chuang8, Hurng-Wern Huang9, Fang-Rong Chang1* and Hsueh-Wei Chang1104*

Author Affiliations

1 Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan

2 Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung, Taiwan

3 Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan

4 Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan

5 Department of Cosmeceutics, College of Pharmacy, China Medical University, Taichung, Taiwan

6 Department of Radiation Oncology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

7 Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan

8 Department of Chemical Engineering, I-Shou University, Kaohsiung, Taiwan

9 Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung, Taiwan

10 Center of Excellence for Environmental Medicine, Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

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BMC Complementary and Alternative Medicine 2012, 12:142  doi:10.1186/1472-6882-12-142

Published: 31 August 2012

Abstract

Background

Methanolic extracts of Gracilaria tenuistipitata (MEGT) were obtained from the edible red algae. Previously, we found that water extract of G. tenuistipitata was able to modulate oxidative stress-induced DNA damage and its related cellular responses.

Methods

In this study, the methanol extraction product MEGT was used to evaluate the cell growth inhibition in oral cancer cells and its possible mechanism was investigated.

Results

The cell viability of MEGT treated Ca9-22 oral cancer cell line was significantly decreased in a dose–response manner (p < 0.05). The sub-G1 population and annexin V intensity of MEGT-treated Ca9-22 cancer cells were significantly increased in a dose–response manner (p < 0.0005 and p < 0.001, respectively). The γH2AX intensities of MEGT-treated Ca9-22 cancer cells were significantly increased in a dose–response manner (p < 0.05). The reactive oxygen species (ROS) and glutathione (GSH)-positive intensities of MEGT-treated Ca9-22 oral cancer cells were significantly increased and decreased, respectively, in a dose–response manner (p < 0.05). The DiOC2(3) intensity for mitochondrial membrane potential (MMP) of MEGT-treated Ca9-22 cancer cells was significantly decreased in a dose–response manner (p < 0.05).

Conclusions

These results indicated that MEGT had apoptosis-based cytotoxicity against oral cancer cells through the DNA damage, ROS induction, and mitochondrial depolarization. Therefore, MEGT derived from the edible algae may have potential therapeutic effects against oral squamous cell carcinoma (OSCC).

Keywords:
Red algae; Oral cancer; Apoptosis; γ-H2AX; ROS; Mitochondrial membrane potential; Glutathione