Cytotoxicity and apoptosis induction of some selected marine bacteria metabolites.
OBJECTIVE
To study the potential apoptosis effects of cytotoxic marine bacterial metabolites on human HeLa cell line.


RESULTS
After HeLa cells were routinely cultured, tetrazolium-based colorimetric assay for cytotoxicity was performed to screen the marine bacteria extracts showing 12 strains active. To find the potential active strain with apoptosis mechanism, a battery of apoptosis assays, including AO/EB staining, TUNEL assay (terminal-deoxynucleotidyl transferase mediated nick end labelling), gel electrophoresis and flow cytometry, were used to determine whether apoptosis was involved in HeLa cell cytotoxicity of marine bacterial extracts. The results indicated that four strains could induce cell shrinkage, cell membrane blebbing, formation of apoptotic body and DNA fragmentation.


CONCLUSIONS
Crude extracts of 12 of 153 strains of marine bacteria showed cytotoxic effects with ID50 ranged from 77.20 to 199.84 microg ml(-1), in which eight strains of bacteria were associated bacteria. The metabolites in the strains of QD1-2, NJ6-3-1, NJ1-1-1 and SS6-4 were able to induce HeLa cells apoptosis. Furthermore, the assessment by flow cytometry indicated that the hypodiploid apoptotic cells increased in a time-dependent manner, suggesting that induced apoptosis occurred from 24 h to 48 h after the extracts treatment.


CONCLUSIONS
Our results suggested that the compounds from fermentation in these four marine bacterial strains could be candidates for developing apoptosis specific anti-tumour agents with lower toxicity. This study indicated that associated marine bacteria could be good source to find cytotoxic metabolites, and some cytotoxic marine bacterial metabolites could have apoptosis mechanisms.
Lin
J
J
Marine Biotechnology Laboratory, Ningbo University, Ningbo, China.
Yan
X-J
XJ
Zheng
L
L
Ma
H-H
HH
Chen
H-M
HM
D017209:Apoptosis; D001419:Bacteria / Q000235:genetics; D018407:Bacterial Physiological Phenomena; D016923:Cell Death; D053938:DNA Fragmentation; D005434:Flow Cytometry; D006367:HeLa Cells / Q000382:microbiology* / Q000473:pathology; D006801:Humans; D020287:In Situ Nick-End Labeling; D008856:Microscopy, Fluorescence; D021521:Ribotyping; D012623:Seawater; D018675:Toxicity Tests; D014871:Water Microbiology