Table 1.

Correlation of log₁₀IC₅₀ values for BetA to drug resistance mechanisms (ABCB1, ABCB5, ABCC1, ABCG2, EGFR, TP53) in the NCI cell line panel.

		Betulinic acid	Control drug
		(log10 IC50, M)	(log10 IC50, M)
ABCB1 expression			Daunorubicin
7q21 (chromosomal	R-value	−0.004	*0.597
Locus of ABCB1 gene)	P-value	0.489	*4.82 × 10−6
ABCB1 expression	R-value	0.036	*0.684
(Microarray)	P-value	0.394	*1.57 × 10−8
ABCB1 expression	R-value	0.153	*0.579
(RT-PCR)	P-value	0.142	*4.19 × 10−6
Rhodamine 123	R-value	0.076	*0.544
Accumulation	P-value	0.286	*1.51 × 10−5
ABCB5 expression			Maytansine
ABCB5 expression	R-value	0.052	*0.454
(Microarray)	P-value	0.347	*6.67 × 10−4
ABCB5 expression	R-value	0.164	*0.402
(RT-PCR)	P-value	0.105	*0.0034
ABCC1 expression			Vinblastine
DNA gene	R-value	0.148	*0.429
Copy number	P-value	0.131	*0.001
ABCC1 expression	R-value	−0.070	*0.399
(Microarray)	P-value	0.302	*0.002
ABCC1 expression	R-value	−0.091	0.299
(RT-PCR)	P-value	0.269	*0.036
ABCG2 expression			Pancratistatin
ABCG2 expression	R-value	−0.092	*0.329
(Microarray)	P-value	0.246	*0.006
ABCG2 expression	R-value	−0.051	*0.346
(Western blot)	P-value	0.352	*0.004
EGFR expression			Erlotinib
EGFR gene	R-value	−0.036	−0.245
Copy number	P-value	0.394	*0.029
EGFR expression	R-value	0.192	*−0.458
(Microarray)	P-value	0.071	*1.15 × 10−4
EGFR expression	R-value	0.203	*0.409
(RNAse protection)	P-value	0.064	*7.08 × 10−4
EGFR expression	R-value	−0.025	*−0.376
(Protein array)	P-value	0.425	*0.001
TP53 mutation			5–Fluorouracil
TP53 mutation	R-value	−0.066	*−0.502
(cDNA sequencing)	P-value	0.312	*3.50 × 10−5
TP53 function	R-value	0.012	*−0.436
(Yeast functional assay)	P-value	0.464	*5.49 × 10−4

^*P < 0.05 and R > 0.3 (or R < −0.3).