Selective amino acid restriction differentially affects the motility and directionality of DU145 and PC3 prostate cancer cells

We previously found that selective restriction of amino acids inhibits invasion of two androgen-independent human prostate cancer cell lines, DU145 and PC3. Here we show that the restriction of tyrosine (Tyr) and phenylalanine (Phe), methionine (Met) or glutamine (Gln) modulates the activity of G proteins and affects the balance between two actin-binding proteins, cofilin and profilin, in these two cell lines. Selective amino acid restriction differentially reduces G protein binding to GTP in DU 145 cells. Tyr/Phe deprivation reduces the amount of Rho-GTP and Rac 1-GTP. Met deprivation reduces the amount of Ras-GTP and Rho-GTP, and GIn deprivation decreases Ras-GTP, 3 Rac-GTP, and Cdc42-GTP. Restriction of these amino acids increases the amount of profilin, cofilin and phosphorylation of cofilin-Ser(3) .Increased PAK 1 expression and phosphorylation of PAK 1-Thr(423), and Ser(199/204) are consistent with the increased phosphorylation of LIMK1-Thr(508). In PC3 cells, Tyr/Phe or GIn deprivation reduces the amount of Ras-GTP, and all of the examined amino acid restrictions reduce the amount of profilin. PAK 1, LIMK I and cofilin are not significantly altered. These data reveal that specific amino acid deprivation differentially affects actin dynamics in DU 145 and PC3. Modulation on Rho, Rac, PAK 1, and LIMK I likely alter the balance between cofilin and profilin in DU 145 cells. In contrast, profilin is inhibited in PC3 cells. These effects modulate directionality and motility to inhibit invasion.