Histone deacetylase inhibitor valproic acid inhibits cancer cell proliferation via down-regulation of the alzheimer amyloid precursor protein.
The beta-amyloid precursor protein (APP) represents a type I transmembrane glycoprotein that is ubiquitously expressed. In the brain, it is a key player in the molecular pathogenesis of Alzheimer disease. Its physiological function is however less well understood. Previous studies showed that APP is up-regulated in prostate, colon, pancreatic tumor, and oral squamous cell carcinoma. In this study, we show that APP has an essential role in growth control of pancreatic and colon cancer. Abundant APP staining was found in human pancreatic adenocarcinoma and colon cancer tissue. Interestingly, treating pancreatic and colon cancer cells with valproic acid (VPA, 2-propylpentanoic acid), a known histone deacetylase (HDAC) inhibitor, leads to up-regulation of GRP78, an endoplasmic reticulum chaperone immunoglobulin-binding protein. GRP78 is involved in APP maturation and inhibition of tumor cell growth by down-regulation of APP and secreted soluble APPalpha. Trichostatin A, a pan-HDAC inhibitor, also lowered APP and increased GRP78 levels. In contrast, treating cells with valpromide, a VPA derivative lacking HDAC inhibitory properties, had no effect on APP levels. VPA did not modify the level of epidermal growth factor receptor, another type I transmembrane protein, and APLP2, a member of the APP family, demonstrating the specificity of the VPA effect on APP. Small interfering RNA-mediated knockdown of APP also resulted in significantly decreased cell growth. Based on these observations, the data suggest that APP down-regulation via HDAC inhibition provides a novel mechanism for pancreatic and colon cancer therapy.
Venkataramani
Vivek
V
Department of Molecular Psychiatry, Alzheimer Ph.D. Graduate School, University of Goettingen, 37075 Goettingen, Germany.
Rossner
Christian
C
Iffland
Lara
L
Schweyer
Stefan
S
Tamboli
Irfan Y
IY
Walter
Jochen
J
Wirths
Oliver
O
Bayer
Thomas A
TA
D016564:Amyloid beta-Protein Precursor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000927:Anticonvulsants / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D015536:Down-Regulation; D000091342:Endoplasmic Reticulum Chaperone BiP; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006801:Humans; D007124:Immunoenzyme Techniques; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D058255:Protease Nexins; D034741:RNA, Small Interfering / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014635:Valproic Acid / Q000494:pharmacology*
C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; D000927:Anticonvulsants; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D056572:Histone Deacetylase Inhibitors; D058255:Protease Nexins; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D014635:Valproic Acid