Sema4D/plexin-B1–mediated attraction of neurotropic tumor cells toward nerves is dependent on activation of RhoA. A: Immunoblot analysis for plexin-B1 and Sema4D on lysates from PC3 and sNF96.2, respectively, infected with empty vector control lentivirus (C) or virus coding for the appropriate shRNA (sh). B: The 0.1% BSA (negative control), 10% FBS (positive control), and sNF96.2 cells were used as the chemoattractants for PC3 in a migration assay. The PC3 and sNF96.2 cells were infected with control lentivirus or lentivirus coding for Sema4D shRNA or plexin-B1 shRNA, where indicated. C: The 0.1% BSA (negative control), 10% FBS (positive control), and either wild-type (wt) or Sema4D knockout (KO) DRG were used as the chemoattractants for PC3, Du-145, or LnCAP cells in an invasion assay. *P < 0.05. n.s., not significant. D: PC3 cells were transfected with empty vector control (ctrl) or the myc-tagged chimeric constructs Trk-A/plexin-B1 wild-type (TrkA-PB1) and Trk-A/plexin-B1 RasGAP mutant (TrkA-PB1 RasGAP mut) and expression checked in an immunoblot. GAPDH was used as a loading control in all immunoblots. E: The 0.1% BSA (BSA, negative control) and NGF, with and without the ROK inhibitor fasudil, were used as the chemoattractants for PC3 cells expressing Trk-A/wild-type plexin-B1 chimeric receptors (TrkA-PB1) or chimeras in which the RasGAP function was lost due to mutation (RasGAP mut), in a migration assay. *P < 0.05. F: The 0.1% BSA (negative control) and sNF96.2 cells were used as the chemoattractants for PC3 cells, control treated or treated with fasudil, in a migration assay. **P < 0.01.