Loss of Postn alters FAK signaling and delays tumor growth at heterotopic sites. (A) Total cell lysates from 3 independent tumors were surveyed for FAK activation. Lower levels of FAK activation (pFAK-Y397) were observed in Postn-null tumors. (B) Western blot analysis for activated Akt (pAkt; S473) and Cyclin D1 showed no differences in Postn(−/−) tumors when compared to wild-type. (C) Tumor volume measurements following the subcutaneous injection of 106 Met-1 cells into the flank of FVB/N wildtype or Postn-null female mice (n=5). No appreciable growth was observed in Postn-null mice suggesting that Postn is required for tumor progression at heterotopic sites. *
(D) Representative tumors excised at 35 days following the injections of Met-1 cells as described in (C).