NOTCH1 and colonic neoplasm: TSC2 negatively regulates Notch1 signaling in an mTOR-dependent and -independent fashion.30, 31 To address whether TSC2 inactivation leads to the increase of Notch signaling through mTOR activation, we first transfected the human colon cancer cell line LS174 with siRNA-targeting TSC2 or non-targeting control (NTC) siRNA (Figure 5a).