Figure 2.

Overexpression of OPN promoted gastric cancer SGC7901 cellular survival in serum depleted condition. (A): Characterization of OPN‐overexpressing SGC7901 clones and vector control clone. Equivalent number of parental SGC7901 cells (P), one vector control SGC7901 clone (V) and three OPN‐producing SGC7901 clones (nos. O3, O19 and O16) were seeded in culture medium in 100 mm culture dishes. Twenty‐four hours later, cells were washed with PBS and undergone starvation in 4 ml serum‐free medium for another 48 hrs. Then the conditional media from the culture were subjected to Western blot assay using anti‐OPN and anti‐Flag antibodies. Levels of β‐actin were monitored as loading control. (B) and (C): Effects of serum starvation and hypoxia on OPN/SGC7901 cell viability. The Vec/SGC7901 and OPN/SGC7901 cells were serum‐starved for one week in the presence or absence of 200 μM CoCl₂. Cells were observed and the cell micrographs were taken in random microscopic fields (×100), and the cell numbers were counted by MTT assay. *P < 0.05 and **P > 0.05 (SPSS 11.0).