Extended Data Fig. 1. Additional data for in vivo transfer of host mitochondria to orthotopic mouse GBM tumors.

(A) GFP-expressing GL261 and SB28 mouse GBM cells were implanted intracranially into wildtype mice (controls for Fig. 1B-F), and tumors were analyzed at animal humane endpoint. Representative confocal microscopy data from orthotopic SB28 and GL261 tumors in wildtype mice are shown. Yellow arrowheads point to GFP^negative (non-tumor) host cells. Shown are single focal planes (xy), as well as z-stacks (zy and xz). (B→D) and (E→H) Mitochondria in-transit from host to GBM cells in orthotopic tumors. Sequential confocal planes (xy) and accompanying orthogonal reconstructions (zy, xz) of SB28 (B→D) and GL261 (E→H) GBM tumors in mice, demonstrating an intercellular connection between a mito::mKate2⁺ host cell (white arrowheads) and GFP⁺ tumor cell. Host mKate2⁺ mitochondria within the intercellular connection are indicated by yellow arrowheads. The mitochondria at the end of the connection are surrounded by GFP signal, corresponding to incorporation in the recipient tumor cell cytoplasm (cyan arrowhead).