title: Chlorella sorokiniana induces mitochondrial-mediated apoptosis in human non-small cell lung cancer cells and inhibits xenograft tumor growth in vivo.
abstract: BACKGROUND
  Lung cancer is one of the leading causes of cancer related deaths worldwide. Marine microalgae are a source of biologically active compounds and are widely consumed as a nutritional supplement in East Asian countries. It has been reported that Chlorella or Chlorella extracts have various beneficial pharmacological compounds that modulate immune responses; however, no studies have investigated the anti-cancer effects of Chlorella sorokiniana (CS) on non-small cell lung cancer (NSCLC).
  
  
  METHODS
  In this study, we evaluated the anti-cancer effects of CS in two human NSCLC cell lines (A549 and CL1-5 human lung adenocarcinoma cells), and its effects on tumor growth in a subcutaneous xenograft tumor model. We also investigated the possible molecular mechanisms governing the pharmacological function of CS.
  
  
  RESULTS
  Our results showed that exposure of the two cell lines to CS resulted in a concentration-dependent reduction in cell viability. In addition, the percentage of apoptotic cells increased in a dose-dependent manner, suggesting that CS might induce apoptosis in human NSCLC cells. Western blot analysis revealed that exposure to CS resulted in increased protein expression of the cleaved/activated forms of caspase-3, caspase-9, and PARP, except caspase-8. ZDEVD (caspase-3 inhibitor) and Z-LEHD (caspase-9 inhibitor) were sufficient at preventing apoptosis in both A549 and CL1-5 cells, proving that CS induced cell death via the mitochondria-mediated apoptotic pathway. Exposure of A549 and CL1-5 cells to CS for 24 h resulted in decreased expression of Bcl-2 protein and increased expression of Bax protein as well as decreased expression of two IAP family proteins, survivin and XIAP.
  
  
  CONCLUSIONS
  We demonstrated that CS induces mitochondrial-mediated apoptosis in NSCLC cells via downregulation of Bcl-2, XIAP and survivin. In addition, we also found that the tumors growth of subcutaneous xenograft in vivo was markedly inhibited after oral intake of CS.
authors.affiliation: Transplant Medicine & Surgery Research Centre, Changhua Christian Hospital, Changhua, Taiwan.|Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Ping-Yi
authors.initials: PY
authors.lastname: Lin
authors.affiliation: Department of Public Health, School of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Ching-Tsan
authors.initials: CT
authors.lastname: Tsai
authors.affiliation: Transplant Medicine & Surgery Research Centre, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Chuang
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan.
authors.forename: Ya-Hsuan
authors.initials: YH
authors.lastname: Chao
authors.affiliation: Biomedical Technology and Device Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan.
authors.forename: I-Horng
authors.initials: IH
authors.lastname: Pan
authors.affiliation: Department of Food Science, National Pingtung University of Science and Technology, Pingtung, Taiwan.
authors.forename: Yu-Kuo
authors.initials: YK
authors.lastname: Chen
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan. lincc@dragon.nchu.edu.tw.|Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan. lincc@dragon.nchu.edu.tw.|Department of Biotechnology, Asia University, Taichung, Taiwan. lincc@dragon.nchu.edu.tw.
authors.forename: Chi-Chen
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Changhua Christian Hospital, Changhua, Taiwan. 156283@cch.org.tw.|School of Medicine, Chung Shan Medical University, Taichung, Taiwan. 156283@cch.org.tw.|School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 156283@cch.org.tw.|Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan. 156283@cch.org.tw.
authors.forename: Bing-Yen
authors.initials: BY
authors.lastname: Wang
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy*; D002708:Chlorella / Q000737:chemistry*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts
keywords: Chlorella sorokiniana; Human non-small cell lung cancer cells; Mitochondrial apoptotic pathway