Background Glioblastomas, the most common and malignant brain tumors of the central nervous system, exhibit high invasive capacity, which hinders effective therapy. LN308 glioma cells decreased levels of SDF-1-induced phosphorylation of ERK1/2 and Akt. Inhibiting CXCR4 in LN229 and LN308 glioma cells that were knocked down for CXCR7 did not further reduce migration towards SDF-1 in hypoxic conditions and did not affect the levels of phosphorylated ERK1/2 and Akt. Analysis of immunoprecipitated CXCR4 from LN229 and LN308 glioma cells revealed co-precipitated CXCR7. Conclusions Taken together, our findings indicate that both CXCR4 and CXCR7 mediate glioma cell migration towards SDF-1 in hypoxic 93129-94-3 IC50 conditions and support the development of therapeutic agents targeting these receptors. tumor growth studies [6]. Ectopic expression of the receptor has been shown to enhance tumor formation in nude mice in vivo[8]. A recent study demonstrated that in prostate cancer, CXCR7 potentially promotes invasion through its downstream targets of CD44 and cadherin-11 [7]. Balabanian and colleagues showed that SDF-1-induced T cell migration was dependent on both CXCR4 and CXCR7, and combined inhibition of these two receptors resulted in additive inhibitory effects on the migration of T cells [2]. Hypoxia is a major player in the microenvironment of gliomas that orchestrates adaptive responses by stimulating the expression of several genes involved in tumorigenesis. However, despite accumulating data, the regulation of CXCR7 by hypoxia and its contribution to glioma migration have not been fully elucidated yet. Here, we show that U87MG, LN229 and LN308 glioma cells express CXCR7 and exposure to hypoxia upregulates CXCR7 protein expression in these cell lines. CXCR7-expressing U87MG, LN229 and LN308 glioma cells migrated towards SDF-1 in hypoxic conditions in the Boyden chamber assays. While shRNA-mediated knockdown of CXCR7 expression did not affect the migration of any of the three cell lines in normoxic conditions, we observed a reduction in the migration of LN229 and LN308, but not U87MG, glioma cells towards SDF-1 in hypoxic conditions. In addition, knockdown of CXCR7 expression in LN229 and LN308 glioma cells 93129-94-3 IC50 decreased levels of SDF-1-induced phosphorylation of Mouse monoclonal to CD19.COC19 reacts with CD19 (B4), a 90 kDa molecule, which is expressed on approximately 5-25% of human peripheral blood lymphocytes. CD19 antigen is present on human B lymphocytes at most sTages of maturation, from the earliest Ig gene rearrangement in pro-B cells to mature cell, as well as malignant B cells, but is lost on maturation to plasma cells. CD19 does not react with T lymphocytes, monocytes and granulocytes. CD19 is a critical signal transduction molecule that regulates B lymphocyte development, activation and differentiation. This clone is cross reactive with non-human primate ERK1/2 and Akt. Inhibiting CXCR4 in LN229 and 93129-94-3 IC50 LN308 glioma cells that were knocked down for CXCR7 did not further reduce migration towards SDF-1 in hypoxic conditions and did not affect the levels of phosphorylated ERK1/2 and Akt. Analysis of immunoprecipitated CXCR4 from LN229 and LN308 glioma cells revealed co-precipitated 93129-94-3 IC50 CXCR7. Taken together, our findings indicate that both CXCR4 and CXCR7 mediate glioma cell migration towards SDF-1 in hypoxic conditions. Results Hypoxia upregulates CXCR7 protein expression We first determined the effect of hypoxia on CXCR7 protein expression in glioma cells. U87MG, LN229 and LN308 glioma cells were cultured in normoxic or hypoxic conditions for 3, 6, 12, 18 and 24 h. Total cell lysates were collected and subjected to Western blot analysis (Figure?1). We observed that U87MG, LN229 and LN308 glioma cells expressed CXCR7. Exposure to hypoxia increased HIF-1 and CXCR7 protein levels in all cell lines. In LN229 (Figure?1b) and LN308 (Figure?1c) glioma cells, hypoxia upregulated CXCR7 protein expression immediately, starting at 3 h and declining after 18 h. Conversely, in U87MG (Figure?1a) glioma cells, hypoxia upregulated CXCR7 protein expression at 18 h, declining slowly thereafter. CXCR7 protein expression was upregulated significantly by two-fold in U87MG and LN229, and three-fold in LN308 glioma cells at 18 h. Figure 1 Hypoxia upregulates CXCR7 protein expression. (a) U87MG, (b) LN229 and (c) LN308 glioma cells were cultured in normoxic or hypoxic conditions for 3, 6, 12, 18 and 24 h. Total cell lysates were collected and analyzed by Western blot for HIF-1 … CXCR7 mediates the migration.