induces Twist1 , Twist2 and Zeb2 but not Snail , Slug, and Zeb1 mRNA expression. Sub-confluent cells were washed twice with PBS(−), pretreated with serum-free medium at pH 7.4, and incubated in serum-free medium at the indicated pH. After 24 h, total RNA was extracted, reverse-transcribed, and amplified by qPCR with specific primer sets. Data are shown as relative expression compared with their levels in LLCm1 cells cultured at pH 7.4. Representative results were shown from three or more independent experiments. *P < 0.05; ***P < 0.001; NS, not significant.