Figure 3. PIK3R1 depletion does not trigger lung SQCC xenograft regression.

A. H226, CaLu-1 and H520 lung SQCC cell lines expressing inducible PIK3R1 shRNA were cultured (72 h) and extracts examined in WB to confirm PIK3R1 shRNA efficiency. Cell lines were expanded in culture and injected subcutaneously into scid/scid mice (~10⁷ cells in 100 μl PBS plus 100 μl matrigel). Graph (top) illustrates the size of each tumor at different times after initiation of treatment; n.s., not significant, two-way ANOVA test. Graph (bottom) shows percent change in size from beginning to end of treatment; n.s., not significant, Chi square test. Mr, relative mobility. B. Lung SQCC cell lines SK-MES and EPLC, with similar p85β and p85α levels, were infected with viruses encoding inducible control or PIK3R2 shRNA; clones were selected and xenografts established in scid/beige as above. We compared tumor growth after doxycycline addition to drinking water. In WB, we tested PIK3R2 shRNA efficiency in reducing p85β levels. The graph indicates the size of each tumor at different times after initiation of treatment. Differences between control and treated tumors was analyzed using a 2-way ANOVA test; n.s., not significant.