Jak1/Jak3 kinase-dependent activation of mTORC1 in CTCL cells. The CTCL cell lines (A) and mitogen preactivated primary leukemic CTCL cells (B) were cultured for 2 hours with medium or 100 U of IL-2, as indicated, in the presence of Jak3 or pan-Jak inhibitor used at the listed concentrations, lysed, and examined with the listed antibodies. (C) The CTCL cell lines were pretreated at 0 and 24 hours with 100 nM nonsense (control) or Jak1- or Jak3-specific siRNA, cultured for an additional 24 hours, lysed, and analyzed with the indicated antibodies. The CTCL cell lines (D) and mitogen preactivated primary leukemic CTCL cells (F) were cultured for 48 hours with medium or 100 U of IL-2, as indicated, in the presence of 1 μM Jak3 inhibitor, 1 μM pan-Jak inhibitor, or 5 nM rapamycin either alone or in combination with the Jak inhibitors as indicated, and analyzed for the proliferative cell rate. The Jak3 and pan-Jak inhibitor-treated CTCL cell lines and preactivated primary cells were also analyzed for the apoptotic cell death rate (E and G, respectively).