Anti-proliferative activity and apoptotic effect of tick salivary gland extracts on human HeLa cells.
OBJECTIVE
The anti-proliferative and apoptotic potential of salivary gland extracts (SGE) of unfed and partially fed adult ixodid ticks were screened using human HeLa cells.


METHODS
Cell growth inhibition activity of SGE was measured by the MTT assay. Cell cycle analysis and quantification of DNA fragmentation was performed by DNA staining with propidium iodide. Annexin V-FITC was used to detect apoptotic cells.


RESULTS
SGE of all ticks examined suppressed HeLa cell proliferation in a dose dependent manner. Extracts from 2-day fed R. appendiculatus females (IC(50) 0.22 mg/ml SGE soluble protein) and 9-day fed A. variegatum females (IC(50) 0.30 mg/ml) were most potent. Species-specific differences in the anti-proliferative effects of SGE were revealed, suggesting that the amount of active compounds in tick salivary glands change during feeding. Total apoptosis (about 12%) and no significant alteration in cell cycle were confirmed for SGE of A. variegatum and R. appendiculatus, and additionally SGE of 5-day fed I. ricinus females (IC(50) 0.64 mg/ml).


CONCLUSIONS
The study shows that tumour cell growth suppressant(s) and/or apoptotic triggers are present in tick salivary glands, however, further research into the characteristics and mode of action of such natural substances is necessary.
Kazimírová
Maria
M
Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia. maria.kazimirova@savba.sk
Dovinová
Ima
I
Rolníková
Terézia
T
Tóthová
Lívia
L
Hunáková
L'ubica
L
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D005260:Female; D006168:Guinea Pigs; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D011817:Rabbits; D012469:Salivary Glands / Q000737:chemistry*; D013987:Ticks / Q000737:chemistry*; D014020:Tissue Extracts / Q000494:pharmacology*
D000970:Antineoplastic Agents; D014020:Tissue Extracts