In vitro cytotoxicity of Strobilanthes crispus ethanol extract on hormone dependent human breast adenocarcinoma MCF-7 cell

Abstract

Background: Strobilanthes crispus has been traditionally used as antidiabetic, anticancer, diuretic, antilytic and laxative agent. However, cytotoxicity and antiproliferative effect of S. crispus is still unclear.

Results: Strobilanthes cripus was able to reduce cell viability and proliferation in MTT and BrdU assays. Both cell cycle progression and Tunel assay suggested that IC50 of S. crispus ethanol extract induced sub-G1 cell cycle phase, and DNA fragmentation. On the other hand, translocation of mitochondria cytochrome c release, induction of caspase 3/7 and p53 while suppress XIAP on treated MCF-7 cell were also observed in this study.

Conclusion: Our findings suggest that S. crispus ethanol extract induced apoptosis and DNA fragmentation on hormone dependent breast cancer cell line MCF-7 via mitochondria dependent p53 apoptosis pathway.

Figure 1

Effects of Strobilanthes crispus extract (IC₅₀ concentration = 30 μg/mL) on cell proliferation of MCF-7 breast cancer cell lines. Cells were seeded in 96-well plates at a density of 10⁵ and treated for 24, 48 and 72 hr. Values are presented as means (n = 3) ± S.E. *signified statistical difference (p < 0.05).

Figure 2

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) induced subG1 apoptotic population (%) in treated breast cancer MCF-7 cells after 24 and 48 hr exposure. Values are presented as means (n = 3) ± S.E. *signified (p < 0.05).

Figure 3

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) induced single and double DNA break strands population (%) in treated breast cancer MCF-7 cells after 48 and 72 hr incubation detected by TUNEL assay. Values are presented as means (n = 3) ± SE. *signified (p < 0.05).

Figure 4

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) induced translocation of cytochrome c into the cytosol of treated breast cancer MCF-7 cells. The relative concentration of cytochrome c was obtained by comparisons to the plotted cytochrome c standard curve. Values are presented as means (n = 3) ± SE. *signified (p < 0.05).

Figure 5

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) induced activation of initiator caspase 8 and 9 in treated breast cancer MCF-7 cells. The relative concentration of caspase 8 and 9 were obtained by comparisons to the plotted caspase 8 and 9 standard curve. Values are presented as means (n = 3) ± S.E. *signified (p < 0.05).

Figure 6

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) induced the activity of effector caspase 3/7 (fold change) in treated MCF-7 cells as compared to control cells. Values are presented as means (n = 3) ± S.E. *signified (p < 0.05).

Figure 7

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) upregulated the level of cyclin dependent kinase 4 and cyclin dependent kinase 2 (fold change) in treated MCF-7 cells as compared to control cells. Values are presented as means (n = 3) ± S.E. *signified (p < 0.05).

Figure 8

Strobilanthes crispus extract (IC₅₀ = 30 μg/mL) induced the expression of tumour suppressor p53 protein while downregulated apoptosis inhibitor protein XIAP (fold change) in treated MCF-7 cells as compared to control cells. Values are presented as means (n = 3) ± S.E. *signified (p < 0.05).