Extracellular vehicles-mediated Twsit1 transferred from tumor cells to brain induces depressive-like behaviors via neuronal morphogenesis

<b>Rationale:</b> Depression is commonly comorbid with cancer and affects therapeutic efficacy and outcome-of-disease. However, the molecular mechanism underlying cancer-induced depression (CID) remains poorly understood. Twist1 is a proto-oncogene driving tumor progression and metastasis, and chronic stress induces Twist1 expression in the medial prefrontal cortex (mPFC). This study aims to investigate the role and mechanisms of tumor-derived Twist1 in CID. <b>Methods:</b> shTwist1 stably expressing 4T1 cells were obtained through lentivirus transduction and puromycin selection. Tumor cells were subcutaneously inoculated into mice to establish a tumor-bearing mice model. Behavioral assays were used to assess depressive-like behaviors in mice. Ultra-high-speed centrifugation was employed to extract extracellular vehicles (EVs) in 4T1 cell medium or serum from tumor-bearing mice. Quantitative polymerase chain reaction and western blot were used to detect the levels of Twist1 mRNA and protein from tumor-derived EVs or mPFC tissue. Lentivirus was injected into the mPFC to knock down Twist1. Intravenous or intranasal administration of tumor or serum-derived EVs were used to investigate the role of EVs-packaged Twist1 in depressive-like behaviors in mice. <b>Results:</b> The present study demonstrated that tumor-derived EVs mediated the inter-organ communication between tumor cells and brain. Pharmacological inhibition of EVs secretion mitigated depressive-like behaviors in tumor-bearing mice. Intravenous or intranasal injection of EVs from tumor cells or serum from tumor-bearing mice into naïve mice induced a depressive-like phenotype. Further investigation identified tumor-derived EVs Twsit1 as a crucial mediator of cancer-induced dendritic atrophy and depressive-like behaviors in tumor-bearing mice. Knockdown of Twist1 in tumor cells significantly alleviated the detrimental effects of tumor-derived EVs on neuronal morphogenesis and prevented their pro-depressant effects. <b>Conclusions:</b> This study demonstrates that tumor-derived EVs containing Twist1 constitute a key pathological driver of cancer-induced depression, revealing a potential therapeutic target for clinical intervention.