APOE and Alzheimer disease: On the other hand, ApoE4 has been shown to exacerbate the cytotoxic effect of Aβ in cellular models such as SK-N-SH and murine N2a neuroblastoma cells in culture [67], and knock out of ApoE in an AD mice model eliminates the signs of the disease [25,31,68], which makes the role of ApoE in amyloid-associated pathological processes more complicated and puzzling.