Frequent coffee consumption has been associated with a reduced risk of colorectal cancer in a number of case-control studies. Coffee is a leading source of methylxanthines, such as caffeine. The induction of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) is an essential feature of tumor angiogenesis, and the hypoxia-inducible factor-1 (HIF-1) transcription factor is known to be a key regulator of this process. In this study, we investigated the effects of caffeine on HIF-1 protein accumulation and on VEGF and IL-8 expression in the human colon cancer cell line HT29 under hypoxic conditions. Our results show that caffeine significantly inhibits adenosineinduced HIF-1␣ protein accumulation in cancer cells. We show that HIF-1␣ and VEGF are increased through A 3 adenosine receptor stimulation, whereas the effects on IL-8 are mediated via the A 2B subtype. Pretreatment of cells with caffeine significantly reduces adenosine-induced VEGF promoter activity and VEGF and IL-8 expression. The mechanism of caffeine seems to involve the inhibition of the extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and Akt, leading to a marked decrease in adenosine-induced HIF-1␣ accumulation, VEGF transcriptional activation, and VEGF and IL-8 protein accumulation. From a functional perspective, we observe that caffeine also significantly inhibits the A 3 receptor-stimulated cell migration of colon cancer cells. Conditioned media prepared from colon cells treated with an adenosine analog increased human umbilical vein endothelial cell migration. These data provide evidence that adenosine could modulate the migration of colon cancer cells by an HIF-1␣/VEGF/IL-8-dependent mechanism and that caffeine has the potential to inhibit colon cancer cell growth.Coffee and tea are the most commonly consumed beverages in the world (Fredholm, 1999). Results of epidemiological studies have not resolved whether coffee consumption is related to colorectal cancer risk. A report by the World Cancer Research Fund concluded that the available evidence was not sufficient to draw any firm conclusions about a decreased risk of colorectal cancer associated with coffee consumption (World Cancer Research Fund/American Institute for Cancer Research, 1997). However, some researchers contend that a link between high consumption of coffee and a low incidence Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org. doi:10.1124/mol.106.032920.ABBREVIATIONS: IL-8, interleukin-8; Cl-IB-MECA, N 6 (3-iodobenzyl)2-chloroadenosine-5ЈN-methyluronamide; DPCPX, 1,3-dipropyl-8-cyclopentylxanthine; MRE 2029F20, N-benzo[1,3]dioxol-5-yl-2-[5-(2,6-dioxo-1,3-dipropyl-2,3,6,7-tetrahydro-1H-purin-8-yl)-1-methyl-1H-pyrazol-3-yloxy