Tumor-selective Blockade of CD47 Signaling with CD47 Antibody for Enhanced Anti-tumor Activity in Malignant Meningioma.

BACKGROUND: Patients with WHO grade III meningioma have a poor prognosis with a median survival of less than two years and a high risk of recurrence. However, traditional treatment options have failed to improve prognosis. Therefore, development of novel immunotherapy targets is urgently needed. CD47 acting as a "don't eat me" signal to macrophages can trigger tumor immune escape. However, the role of CD47 in malignant meningioma is not well understood. METHODS: We collected 190 clinical meningioma samples and detected the expression of CD47 and immune infiltration in WHO grade I-III by immunohistochemistry, western blot, qPCR. We also examined the functional effects of anti-CD47 on cell proliferation, migration and invasion, macrophagemediated phagocytosis and tumorigenicity both in vitro and in vivo. RESULTS: We found that the expression of CD47 was increased in malignant meningioma along with a decreased number of T cells and an increase in CD68+ macrophages. Blocking CD47 with anti-CD47 antibody (B6H12) suppressed tumor cell growth, motility and promoted macrophage-mediated phagocytosis in IOMM-Lee cells in vitro. In vivo experiments showed that anti-CD47 antibody (B6H12 or MIAP301) significantly inhibited the tumor growth and this effect was partly blocked by the depletion of macrophages. Finally, p-ERK and EGFR showed higher expression in malignant meningioma with high expression of CD47, which was verified by western blot. CONCLUSION: Our results demonstrated that CD47 maybe involved in the meningioma progression and prognosis and offered a novel therapeutic option by targeting CD47 in malignant meningioma.

Inhibition of integrated stress response protects against lipid-induced senescence in hypothalamic neural stem cells in adamantinomatous craniopharyngioma.

BACKGROUND: Adamantinomatous craniopharyngioma (ACP) is a benign tumor with malignant clinical manifestations. ACP adjacent to the hypothalamus often presents with more severe symptoms and higher incidence of hypothalamic dysfunction. However, the mechanism underlying hypothalamic dysfunction remains unclear. METHODS: Immunostaining was performed to determine the nerve damage to the floor of the third ventricle (3VF) adjacent to ACP and to examine the recruitment and senescence of hypothalamic neural stem cells (htNSCs). The accumulation of lipid droplets (LDs) in htNSCs was evaluated via BODIPY staining, oil red O staining, and transmission electron microscopy. In vitro and in vivo assays were used to evaluate the effect of cystic fluid or oxidized low-density lipoprotein and that of oxytocin (OXT) on htNSC senescence and the hypothalamic function. The protein expression levels were analyzed using western blotting. RESULTS: htNSCs with massive LD accumulation were recruited to the damaged 3VF adjacent to ACP. The LDs in htNSCs induced senescence and reduced neuronal differentiation; however, htNSC senescence was effectively prevented by inhibiting either CD36 or integrated stress response (ISR) signaling. Furthermore, OXT pretreatment reduced lipotoxicity via the inhibition of ISR signaling and the repair of the blood-brain barrier. CONCLUSIONS: Reduced LD aggregation or ISR signaling inhibition prevented senescence in htNSCs and identified molecular pathways and potential therapeutic targets that may improve hypothalamic dysfunction in ACP patients.

CD47 promotes the proliferation and migration of adamantinomatous craniopharyngioma cells by activating the MAPK/ERK pathway, and CD47 blockade facilitates microglia-mediated phagocytosis.

AIMS: CD47 is overexpressed in multiple tumours and plays an important role in immune escape and other biological processes of tumours. However, its role in adamantinomatous craniopharyngioma (ACP) remains unclear. Therefore, we explored the functions of CD47 in ACP. METHODS: In this study, the expression of CD47 and the infiltration of immune cells in ACP was determined by immunohistochemistry (IHC) or immunofluorescence. Microglia-mediated phagocytosis was analysed using an in vitro phagocytosis assay. Using lentivirus transfection, CD47 was either silenced or overexpressed in primary ACP cells and the biological effects of CD47 on these cells were evaluated in vitro using cell viability, flow cytometry, wound healing, Transwell migration and 3D hydrogel assays. The protein expression levels were analysed by western blotting. RESULTS: Finger-like protrusions, which may be the key factor in the recurrence of ACP, were primarily found in the region of hypothalamic involvement. The expression of CD47 was higher in palisading epithelium compared with stellate reticulum and epithelial whorls. An in vitro phagocytosis assay showed that CD47 blockade could promote microglia-mediated phagocytosis. Functional assays revealed that CD47 promoted the growth, migration and invasion of ACP cells in vitro. Our mechanistic investigations showed that CD47 activated the MAPK/ERK pathway, thereby facilitating the biological behaviour of ACP cells. CONCLUSIONS: Here, we demonstrated that CD47 plays an important role in ACP cells, suggesting that CD47 could be a new potential therapeutic target for ACP, and adding to the body of literature a role for the inhibition of MAPK/ERK in ACP.