Table 2.

Apoptotic indices following exposure to As₂S₂ in human breast cancer cell lines

Apoptotic Index (folds of control)
Breast cancer cell lines	Exposure time	As2S2 concentrations (µM)
		0	4	8	12	16
MCF-7	24 h	1	1.18±0.12	1.34±0.16	1.45±0.13	1.40±0.11
	48 h	1	2.03±0.28	2.76±0.27	3.70±0.53**	3.54±0.67*
	72 h	1	1.69±0.36	2.60±0.32	3.80±0.61**	4.33±0.47**
MDA-MB-231	24 h	1	1.08±0.04	1.22±0.09	1.33±0.06*	1.21±0.08
	48 h	1	1.48±0.08	1.77±0.17*	1.99±0.10**	2.08±0.21**
	72 h	1	2.91±0.15	4.17±0.18*	4.33±0.06*	5.68±1.31**

Data are the means ± SEM from at least three independent experiments.

^* P < 0.05 vs. control (As₂S₂ 0 µM);

^** P < 0.01 vs. control (As₂S₂ 0 µM).