RPS6KB1 and cancer: To further explore the vulnerability of mTORC1 hyper-activated tumours to HDACi in other cancer cells, a human glioblastoma cell line LN229 was stably transfected with constitutively active Rheb (S16H), an upstream activator of mTOR, which activated mTOR signalling in neurons.48 As expected, the overexpression of Rheb (S16H) increased mTORC1 signalling, as indicated by increased phosphorylation of both p70 S6K and rpS6 (Supplementary Fig. S5A).