Roles of arrest-defective protein 1(225) and hypoxia-inducible factor 1alpha in tumor growth and metastasis.
BACKGROUND
Vascular endothelial growth factor A (VEGFA), a critical mediator of tumor angiogenesis, is a well-characterized target of hypoxia-inducible factor 1 (HIF-1). Murine arrest-defective protein 1A (mARD1A(225)) acetylates HIF-1alpha, triggering its degradation, and thus may play a role in decreased expression of VEGFA.


METHODS
We generated Apc(Min/+)/mARD1A(225) transgenic mice and quantified growth of intestinal polyps. Human gastric MKN74 and murine melanoma B16F10 cells overexpressing mARD1A(225) were injected into mice, and tumor growth and metastasis were measured. VEGFA expression and microvessel density in tumors were assessed using immunohistochemistry. To evaluate the role of mARD1A(225) acetylation of Lys532 in HIF-1alpha, we injected B16F10-mARD1A(225) cell lines stably expressing mutant HIF-1alpha/K532R into mice and measured metastasis. All statistical tests were two-sided, and P values less than .05 were considered statistically significant.


RESULTS
Apc(Min/+)/mARD1A(225) transgenic mice (n = 25) had statistically significantly fewer intestinal polyps than Apc(Min/+) mice (n = 21) (number of intestinal polyps per mouse: Apc(Min/+) mice vs Apc(Min/+)/mARD1A(225) transgenic mice, mean = 83.4 vs 38.0 polyps, difference = 45.4 polyps, 95% confidence interval [CI] = 41.8 to 48.6; P < .001). The growth and metastases of transplanted tumors were also statistically significantly reduced in mice injected with mARD1A(225)-overexpressing cells than in mice injected with control cells (P < .01). Moreover, overexpression of mARD1A(225) decreased VEGFA expression and microvessel density in tumor xenografts (P < .04) and Apc(Min/+) intestinal polyps (P = .001). Mutation of lysine 532 of HIF-1alpha in B16F10-mARD1A(225) cells prevented HIF-1alpha degradation and inhibited the antimetastatic effect of mARD1A(225) (P < .001).


CONCLUSIONS
mARD1A(225) may be a novel upstream target that blocks VEGFA expression and tumor-related angiogenesis.
Lee
Mi-Ni
MN
Division of Life and Pharmaceutical Sciences, Ewha Women's University, Seoul, Korea.
Lee
Shi-Nai
SN
Kim
Se-Hee
SH
Kim
Bora
B
Jung
Bo-Kyung
BK
Seo
Ji Hae
JH
Park
Ji-Hyeon
JH
Choi
Jae-Hoon
JH
Yim
Sun Hee
SH
Lee
Mi-Ran
MR
Park
Jong-Gil
JG
Yoo
Ji-Young
JY
Kim
Jeong Hun
JH
Lee
Seung-Taek
ST
Kim
Hwan-Mook
HM
Ryeom
Sandra
S
Kim
Kyu-Won
KW
Oh
Goo Taeg
GT
D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007417:Intestinal Polyps / Q000378:metabolism* / Q000473:pathology*; D008175:Lung Neoplasms / Q000378:metabolism / Q000556:secondary; D008239:Lysine; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008822:Mice, Transgenic; D008833:Microcirculation; D009154:Mutation; D063209:N-Terminal Acetyltransferase A; D063213:N-Terminal Acetyltransferase E; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000517:prevention & control*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D000123:Acetyltransferases; D063209:N-Terminal Acetyltransferase A; C508558:Naa10 protein, mouse; D063213:N-Terminal Acetyltransferase E; D008239:Lysine