Figure 3: DNA microarray analysis of DBT-induced specific gene expressions and validation in cultured MG-63 cells. (a) MG-63 cells were treated with 1 mg mL−1 RA, RAS, or DBT for 24 h and subjected to DNA microarray analysis to determine the differential gene expressions. The DNA chip contained 7458 candidate genes and 384 reference genes: these sequences were derived from human genome. Significant changes of gene expressions were defined as regulated, either up-regulation when fluorescent signal in the sample was greater than that of control for 200%, or down-regulation when the signal was less than that for 50%. (b) Some of up-regulated genes as in (a) was validated by quantitative real-time PCR analysis. Total RNAs were extracted from cultures treated with different extracts for 24 h and used to perform real-time PCR analysis to determine the mRNA levels of CCL-2, CCL-7, CCL-8, and galectin-9. Data are normalized by ΔΔC t method using 18S rRNA as an internal control, and expressed as the ratio to basal reading where control (without herbal extract) equals to 1, and in mean ± SEM, where n = 5, each with triplicate samples.