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. 2011 Jan 10;6(1):e15864. doi: 10.1371/journal.pone.0015864

Figure 4. Western blot analysis of G2 cell cycle regulatory proteins and the relevance to O2 sensitivity in the ovarian cancer cell lines.

Figure 4

Protein lysates prepared from the ovarian cancer cell lines maintained in growth medium consisting of increasing concentrations of serum and 21% or 3% O2 were analyzed by Western blot. (A) Compared to O2 sensitive cell lines, decreased expression of the core components involved in G2/M cell cycle progression CDC2/cyclin B1 complex and its activator CDC25c is observed in the O2 insensitive cell lines (indicated by asterisk and italics), while the expression of 14-3-3 σ, a protein that inhibits CDC2 is elevated in the O2 insensitive cell lines. (B) Phosphorylation of RB and Wee1 were monitored as an indicator for CDC2 function because both RB and Wee1 are known targets for phosphorylation by CDC2. Equal loading of protein extracts were monitored by probing the stripped Western blots with the primary antibody for β-actin.