WWOX suppresses Tax-mediated cellular transformation and tumor formation. (A) Generation of Rat-1 stable cell lines expressing Tax alone or together with Myc-WWOX or Myc-WWOX Y33R. IB analysis was used to detect protein expression levels of Tax, Myc-WWOX and Myc-WWOX Y33R in the Rat-1 stable cell lines. (B) WWOX inhibition of Tax-mediated colony formation. The indicated Rat-1 stable cells were plated in soft agar for colony formation. These data represent mean (± SD), and values *P < .05 or **P < .01 were using the Student t test. (C) WWOX inhibition of Tax-mediated tumorigenesis. The Rat-1 stable cells were subcutaneously inoculated into to the left and right hind back of severe combined immunodeficient mice. Photographs were taken at day 14 after inoculation. (D) Summary of tumor weight expressed in panel C. These data represent mean (± SD) for n = 3 samples. *P < .05 or **P < .01 using the Student t test.