TABLE 5.

Effects of siRNA knockdown of ATR and ATM pathway components on DIT7 cell viability after induction of convergent transcription

Target	siRNA	Transcription (%)a		% of viable cells		Significance (P value)
		Sense	Antisense	−Dox and RSL1b	+Dox and RSL1 (normalized)c
Vimentin	siRNA	100	100	97 ± 1.7	53 ± 2.5
ATR	siRNA1	108	113	94 ± 3.2	38 ± 3.2	<0.01
	siRNA2	87	72	69 ± 4.3	35 ± 2.9	<0.001
CHK1	siRNA1	93	70	59 ± 2.8	33 ± 3.3	<0.0001
	siRNA2	84	54	71 ± 3.4	30 ± 1.1	<0.0001
ATRIP	siRNA1	106	70	98 ± 1.3	26 ± 1.5	<0.0001
TOPBP1	siRNA1	93	112	95 ± 2.5	40 ± 1.2	<0.0001
ATM	siRNA1	89	87	89 ± 3.6	67 ± 2.6	<0.001
	siRNA2	94	91	93 ± 2.1	74 ± 3.9	<0.001
CHK2	siRNA1	91	86	89 ± 1.1	51 ± 1.2	NSd
	siRNA2	108	94	96 ± 1.8	56 ± 1.0	NS
p53	siRNA1	122	110	83 ± 2.5	79 ± 3.5	<0.001
	siRNA2	83	89	96 ± 1.8	76 ± 2.6	<0.0001

^aSense and antisense transcription through the HPRT minigene in the presence of Dox plus RSL1 was measured by real-time RT-PCR at day 1 after the second treatment with siRNAs at day 0 and expressed as a percentage of the induced transcript levels measured in the presence of vimentin siRNA. Results were averaged from three determinations.

^bViable cells were counted 4 days after treatment with siRNAs (200 nM) in the absence of doxycyline (Dox) plus RSL1. siRNAs were transfected twice: at day −2 and day 0. Viable cells after siRNA treatment are expressed as a percentage of the count of untreated cells, which was defined as 100%. Mean percentages ± SD were determined from at least six independent measurements.

^cCell counts were normalized to (divided by) the cell counts in the absence of doxycycline and RSL1 and expressed as a percentage of the values for vimentin siRNA. Viable cells in the sixth column = (measured viable cells [not shown]) × (viable cells in the noninduced control [vimentin siRNA] in the fifth column)/(viable cells in noninduced treatment [specific siRNA] in the fifth column). Mean percentages ± SD were determined from at least six independent measurements.

^dNS, not significant.