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. Author manuscript; available in PMC: 2023 Sep 1.
Published in final edited form as: Clin Cancer Res. 2022 Sep 1;28(17):3836–3849. doi: 10.1158/1078-0432.CCR-22-1052

Figure 2.

Figure 2.

Activating TORC1 signaling confers resistance to trametinib in BT-40 cells. A, TSC2 was suppressed using shRNA. Cells were exposed to trametinib (2 or 5 nmol/L) for 12 or 24 hours. Trametinib inhibited phosphorylation of 4E-BP1 in control transfected cells but not in cells where TSC2 had been down regulated. B, Expression of shTSC2ΔGAP-Myc (red arrow) increases p4E-BP1 that is not inhibited by trametinib. C, Activating TORC1, by knockdown of TSC2, or expression of constitutively active myrAkt1 or myrAkt3 induces trametinib resistance in BT-40 cells. D, Knockdown of PTEN confers trametinib resistance in BT-40 cells. Left, PTEN was suppressed using lentivirus encoded shRNA. After 48 hours cells were exposed to trametinib (2–10 nmol/L) for 24 hours, and lysates probed for PTEN and total and phosphorylated ERK1/2. β-actin was used as a loading control. Right, BT-40 cells were infected with control virus (shControl), or two shPTEN lentiviruses. Cells infected with lentivirus were subjected to 2 days’ selection with 1 ug/mL puromycin, and then used for the subsequent assay. Cells were exposed to trametinib for 48 hours (n = 3 ± SD).