Reciprocal interactions between innate immune cells and astrocytes facilitate neuroinflammation and brain metastasis via lipocalin-2

Adler et al. identify granulocyte-derived lipocalin-2 as a mediator of inflammatory astrocyte activation, which in turn facilitates brain metastasis in breast cancer and melanoma. Brain metastasis still encompass very grim prognosis and therefore understanding the underlying mechanisms is an urgent need toward developing better therapeutic strategies. We uncover the intricate interactions between recruited innate immune cells and resident astrocytes in the brain metastatic niche that facilitate metastasis of melanoma and breast cancer. We show that granulocyte-derived lipocalin-2 (LCN2) induces inflammatory activation of astrocytes, leading to myeloid cell recruitment to the brain. LCN2 is central to inducing neuroinflammation as its genetic targeting or bone-marrow transplantation from LCN2(-/-) mice was sufficient to attenuate neuroinflammation and inhibit brain metastasis. Moreover, high LCN2 levels in patient blood and brain metastases in multiple cancer types were strongly associated with disease progression and poor survival. Our findings uncover a previously unknown mechanism, establishing a central role for the reciprocal interactions between granulocytes and astrocytes in promoting brain metastasis and implicate LCN2 as a prognostic marker and potential therapeutic target.

Automated summary

Adler et al. have identified granulocyte-derived lipocalin-2 (LCN2) as a mediator of inflammatory astrocyte activation, which promotes brain metastasis in breast cancer and melanoma. Their findings highlight the importance of understanding the interactions between immune cells and astrocytes in the brain metastatic niche for developing better therapeutic strategies. LCN2 has been shown to induce neuroinflammation and its high levels in patient blood and brain metastases are strongly associated with disease progression and poor survival, making it a potential prognostic marker and therapeutic target.