In vitro and in vivo characterization of the anticancer activity of Thai stingless bee (Tetragonula laeviceps) cerumen.
Tetragonula laeviceps cerumen was sequentially extracted with 80% (v/v) methanol, dichloromethane, and hexane and also in the reverse order. By the MTT assay and the respective 50% inhibition concentration value, the most active fraction was further purified to apparent homogeneity by bioassay-guided silica gel column chromatography. α-Mangostin was identified by high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analyses. It had a potent cytotoxicity against the BT474, Chago, Hep-G2, KATO-III, and SW620 cell lines (IC50 values of 1.22 ± 0.03, 2.25 ± 0.20, 0.94 ± 0.01, 0.88 ± 0.16, and 1.50 ± 0.39 µmol/L, respectively). The in vitro cytotoxicity of α-mangostin against the five human cancer cell lines and primary fibroblasts was further characterized by real-time impedance-based analysis. Interestingly, α-mangostin was more cytotoxic against the cancer-derived cell lines than against the primary fibroblasts. Later, the migration assay was performed by continuously measuring the attachment of cells to the plate electrodes at the bottom of the transwell membrane. The combined caspase-3 and -7 activities were assayed by the Caspase-Glo® 3/7 kit. It showed that the cytotoxic mechanism involved caspase-independent apoptosis, while at low (non-toxic) concentrations α-mangostin did not significantly alter cell migration. Furthermore, the in vivo cytotoxicity and angiogenesis were determined by alkaline phosphatase staining in zebrafish embryos along with monitoring changes in the transcript expression level of two genes involved in angiogenesis (vegfaa and vegfr2) by quantitative real-time reverse transcriptase- polymerase chain reaction. It was found that the in vivo cytotoxicity of α-mangostin against zebrafish embryos had a 50% lethal concentration of 9.4 µM, but no anti-angiogenic properties were observed in zebrafish embryos at 9 and 12 µM even though it downregulated the expression of vegfaa and vegfr2 transcripts. Thus, α-mangostin is a major active compound with a potential anticancer activity in T. laeviceps cerumen in Thailand.
Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Pongvit
P
Nugitrangson
Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
Songchan
S
Puthong
National Nanotechnology Center, National Science and Technology Development Agency, Thanon Phahonyothin, Tambon Khlong Nueng, Amphoe Khlong Luang, Pathum Thani 12120, Thailand.
Tawin
T
Iempridee
National Nanotechnology Center, National Science and Technology Development Agency, Thanon Phahonyothin, Tambon Khlong Nueng, Amphoe Khlong Luang, Pathum Thani 12120, Thailand.
Wittaya
W
Pimtong
Research Centre for Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand chanpen@sc.chula.ac.th.
Surachai
S
Pornpakakul
Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Chanpen
C
Chanchao
D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000378:metabolism*; D001516:Bees / Q000737:chemistry*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002571:Cerumen / Q000737:chemistry*; D004625:Embryo, Nonmammalian / Q000187:drug effects; D005562:Formazans / Q000032:analysis; D020869:Gene Expression Profiling; D006801:Humans; D066298:In Vitro Techniques; D020128:Inhibitory Concentration 50; D008297:Male; D013778:Tetrazolium Salts / Q000032:analysis; D013785:Thailand; D044004:Xanthones / Q000302:isolation & purification / Q000378:metabolism*; D015027:Zebrafish
D000970:Antineoplastic Agents; D005562:Formazans; D013778:Tetrazolium Salts; D044004:Xanthones; C079782:MTT formazan; C021053:mangostin
Tetragonula laeviceps; cancer; cerumen; cytotoxicity; α-mangostin