Failure of the PTEN/aPKC/Lgl Axis Primes Formation of Adult Brain Tumours in Drosophila

Figure 3

The activated form of aPKC induces neoplastic growth in type II NBs of the larval brain, and PI3K contributes to the overall growth. ((a)–(c)) Representative brains from Optix-PI3K (a), (b), and Optix- (c) late L3 larvae grown at 25°C. Repo (red) stains glial cells and Mira (cyan) stains NBs. The lower panel shows Mira staining alone. While Mira marks mainly OL and CB type I NBs in (a) (arrows), aPKC activation triggers an increase in type II NBs (arrowhead) which form invasive masses (arrowheads) in cooperation with the active form of PI3K (c). ((d)–(f)) Representative brains from Optix-PI3K (d), (e), and Optix- (f) late L3 larvae grown at 29°C. Elav and Repo (red) stain neurons and glial cells, respectively, and Mira (cyan) stains NBs. The lower panel shows Mira staining alone. As it happens at 25°C, while Mira marks mainly OL and CB type I NBs in (a) (arrow), aPKC activation triggers a huge increase in type II NBs (arrowhead), which form invasive clusters (inset in the (e) upper panel) and grow as to fill the entire brain lobe in cooperation with the active form of PI3K (f). Scale bars are 50 μm.

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