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. Author manuscript; available in PMC: 2008 Mar 21.
Published in final edited form as: J Biol Chem. 2006 Mar 9;281(24):16681–16690. doi: 10.1074/jbc.M600223200

FIGURE 4. Ghrelin isexpressedinandsecretedby astrocytoma cells, and specific ghrelin knockdown reveals an autocrine role in cell motility.

FIGURE 4

A, shown are the results from real-time PCR analysis of ghrelin mRNA expression in astrocytoma cell lines normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). All primers spanned the exon boundaries to prevent amplification of genomic DNA. Compared with NHAs, human U-87 and SW1088 astrocytoma cells expressed the highest levels of ghrelin mRNA. The PCR product was visualized on 2% agarose gel (lower panel); no product was generated from cDNA samples prepared by omitting the reverse transcriptase. CCT and CCFST, CCF-STTG1; Neg C, negative control. B, ghrelin secretion by astrocytoma cells is shown. SW1088 cells secreted the highest levels of ghrelin compared with NHAs, and ghrelin siRNA resulted in significant reduction of secreted ghrelin protein. C, control. C, ghrelin siRNA (Sequences 1 (S1) and 2 (S2)) inhibited MMP2 activity and Rac expression (lower panels) in U-87 and SW1088 cells without affecting MMP9 activity. WB, Western blot. D, specific ghrelin down-regulation by siRNA resulted in significant inhibition of U-87 cell motility in a scratch assay. Seq 1, Sequence 1.