Project description:Brain metastasis is a dismal complication of cancer that hinges on the initial survival and outgrowth of disseminated cancer cells. To better understand these crucial early stages of brain metastatic colonization, we investigated two prevalent sources of cerebral relapse in the clinic, triple-negative breast cancer (TNBC) and HER2+ breast cancer (HER2BC). We elucidated distinctive early tumor architectures, physical and functional stromal interfaces, and autocrine growth programs employed by these two tumor types to colonize the brain. TNBC cells form extensive perivascular sheath colonies with diffusive contact with astrocytes and microglia. In striking contrast, heightened autonomous deposition of several extracellular matrix components prompts HER2BC cells to colonize the brain as compact, spheroidal colonies, segregating stromal cells to the periphery of the colony. Single-cell dissection of the spatially resolved tumor microenvironment (TME) reveals that brain metastases activate – to different degrees – the canonical stages of the disease-associated microglia (DAM) response previously defined in Alzheimer’s disease. Differential engagement of paracrine tumor-DAM signaling through the receptor AXL suggests specific pro-metastatic functions of the tumor architecture in both TNBC perivascular and HER2BC spheroidal colonies. Collectively, our findings illuminate the distinct stereospatial features of two different yet highly efficient modes of brain colonization, and the relevance of these features in future efforts to leverage the TME to treat brain metastasis.
Project description:Brain metastasis is a dismal complication of cancer that hinges on the initial survival and outgrowth of disseminated cancer cells. To better understand these crucial early stages of brain metastatic colonization, we investigated two prevalent sources of cerebral relapse in the clinic, triple-negative breast cancer (TNBC) and HER2+ breast cancer (HER2BC). We elucidated distinctive early tumor architectures, physical and functional stromal interfaces, and autocrine growth programs employed by these two tumor types to colonize the brain. TNBC cells form extensive perivascular sheath colonies with diffusive contact with astrocytes and microglia. In striking contrast, heightened autonomous deposition of several extracellular matrix components prompts HER2BC cells to colonize the brain as compact, spheroidal colonies, segregating stromal cells to the periphery of the colony. Single-cell dissection of the spatially resolved tumor microenvironment (TME) reveals that brain metastases activate – to different degrees – the canonical stages of the disease-associated microglia (DAM) response previously defined in Alzheimer’s disease. Differential engagement of paracrine tumor-DAM signaling through the receptor AXL suggests specific pro-metastatic functions of the tumor architecture in both TNBC perivascular and HER2BC spheroidal colonies. Collectively, our findings illuminate the distinct stereospatial features of two different yet highly efficient modes of brain colonization, and the relevance of these features in future efforts to leverage the TME to treat brain metastasis.
Project description:Brain metastasis is a dismal complication of cancer that hinges on the initial survival and outgrowth of disseminated cancer cells. To better understand these crucial early stages of brain metastatic colonization, we investigated two prevalent sources of cerebral relapse in the clinic, triple-negative breast cancer (TNBC) and HER2+ breast cancer (HER2BC). We elucidated distinctive early tumor architectures, physical and functional stromal interfaces, and autocrine growth programs employed by these two tumor types to colonize the brain. TNBC cells form extensive perivascular sheath colonies with diffusive contact with astrocytes and microglia. In striking contrast, heightened autonomous deposition of several extracellular matrix components prompts HER2BC cells to colonize the brain as compact, spheroidal colonies, segregating stromal cells to the periphery of the colony. Single-cell dissection of the spatially resolved tumor microenvironment (TME) reveals that brain metastases activate – to different degrees – the canonical stages of the disease-associated microglia (DAM) response previously defined in Alzheimer’s disease. Differential engagement of paracrine tumor-DAM signaling through the receptor AXL suggests specific pro-metastatic functions of the tumor architecture in both TNBC perivascular and HER2BC spheroidal colonies. Collectively, our findings illuminate the distinct stereospatial features of two different yet highly efficient modes of brain colonization, and the relevance of these features in future efforts to leverage the TME to treat brain metastasis.
Project description:Brain metastasis is a dismal cancer complication, hinging on the initial survival and outgrowth of disseminated cancer cells. To understand these crucial early stages of colonization, we investigated two prevalent sources of cerebral relapse, triple-negative (TNBC) and HER2+ breast cancer (HER2BC). We show that these tumor types colonize the brain aggressively, yet with distinct tumor architectures, stromal interfaces, and autocrine growth programs. TNBC forms perivascular sheaths with diffusive contact with astrocytes and microglia. In contrast, HER2BC forms compact spheroids prompted by autonomous extracellular matrix components and segregating stromal cells to their periphery. Single-cell transcriptomic dissection reveals canonical Alzheimer's disease-associated microglia (DAM) responses. Differential engagement of tumor-DAM signaling through the receptor AXL suggests specific pro-metastatic functions of the tumor architecture in both TNBC perivascular and HER2BC spheroidal colonies. The distinct spatial features of these two highly efficient modes of brain colonization have relevance for leveraging the stroma to treat brain metastasis.
Project description:Less than 8% of patients diagnosed with pancreatic ductal adenocarcinomas (PDAC) survive more than five years in part due to late stage diagnosis. Approximately half of PDAC patients exhibit loss of SMAD4, which correlates with increased metastatic disease. Here we demonstrate that SMAD4 is a suppressor of metastatic colonization. Using isogenic human PDAC cell lines expressing or lacking SMAD4, both in vitro and in vivo, we define SMAD4-dependent gene expression changes in metastatic lesions. We performed a pooled in vivo open reading frame (ORF) screen of SMAD4 transcriptional targets and identified genes that, induce tumor seeding and growth at secondary sites. We found that expression of the transcription factor FOSL1 was sufficient to drive metastatic colonization. SMAD4 directly binds and represses the activity of the FOSL1 enhancer. These studies demonstrate a direct role for SMAD4 in regulating metastatic colonization and identify FOSL1 as a SMAD4-regulated gene involved in PDAC progression.
Project description:This SuperSeries is composed of the following subset Series: GSE14682: Metastatic breast cancer to the brain: set 1 GSE14683: Metastatic breast cancer to the brain: set 2 Refer to individual Series