Tunneling nanotubes regulate mitochondrial homeostasis between glioblastoma and astrocytes, and between tumor cells in vivo.

Tumor progression is driven by cancer cells' ability to establish a cellular network through tunneling nanotube-like connections (TNTs), which enable mitochondrial exchange both within the tumor cells and with the tumor microenvironment (TME). However, the functional consequences of mitochondrial transfer between tumor and non-tumor cells, and its occurrence in vivo, remain poorly understood. Here we show bidirectional mitochondrial transfer between Glioblastoma (GBM) cells and non-tumoral astrocytes (AS). We report that transfer of damaged mitochondria from GBM cells to AS is associated with activation of mitophagy in recipient cells, while astrocyte-derived mitochondria to GBM cells correlates with changes in mitochondrial activity and metabolic readouts. Furthermore, intravital subcellular microscopy (ISMic) in a live animal model allows the visualization of TNT connections with characteristics similar to those observed in vitro and supported TNT-mediated mitochondrial transfer in vivo. These findings reveal a potential mechanism of tumor adaptation and highlight TNTs as promising therapeutic targets.