Gene Expression Profile of B16(F10) Murine Melanoma Cells Exposed to Hypoxic Conditions In Vitro

Abstract

Hypoxia is an important feature of tumor microenvironment, exerting far-reaching effects on cells and contributing to cancer progression. Previous studies have established substantial differences in hypoxia response between various cell lines. Investigating this phenomenon in melanoma cells contributes to a better understanding of cell lineage-specific hypoxia response and could point out novel hypoxia-regulated genes. We investigated transcriptional activity of B 16(F10) murine melanoma cells cultured for 24 h under hypoxic (nominal 1% O2, 15 samples including controls) and hypoxia-mimicking conditions (cobalt chloride, 100 or 200 microM, 6 samples including controls). Gene expression profiles were analyzed using MG-U74Av2 oligonucleotide microarrays. Data analysis revealed 2541 probesets (FDR <5%) for 1% oxygen experiment and 364 probesets (FDR <5%) for cobalt chloride, which showed differences in expression levels. Analysis of hypoxia-regulated genes (true hypoxia, 1% O2) by stringent Family-Wise Error Rate estimation indicated 454 significantly changed transcripts (p < 0.05). The most upregulated genes were Lgals3, Selenbpl, Nppb (more than ten-fold increase). We observed significant differences in expression levels of genes regulating glycolysis (Pfkp, Hk2, Aldo3, Eno2), apoptosis (Bnip3, Bnip31, Cdknla), transcription (Bhlhb2, Sap30, Atf3, Mxil), angiogenesis (Vegfa, Adm, Anxa2, Ctgf), adhesion (Pkp2, Itga4, Mcam), migration (Cnn2, Tmsb4x), and other processes. Both true hypoxia and hypoxia mimicry induced HIF-1-regulated genes. However, unsupervised analysis (Singular Value Decomposition) revealed distinct differences in gene expression between these two experimental conditions. Contrary to hypoxia, cobalt chloride caused suppression of gene expression rather than stimulation, especially concerning transcripts related to proliferation, immune response, DNA repair, and melanin biosynthesis.

Heterogeneous Nuclear Ribonucleoprotein K (hnRNP-K) Promotes Tumor Metastasis by Induction of Genes Involved in Extracellular Matrix, Cell Movement, and Angiogenesis

“…These data revealed that the overexpression of hnRNP-K promoted metastasis by induction of signaling cascades involved in extracellular matrix, cell adhesion, invasion, and angiogenesis. Tmsb4x, an actin monomer-binding protein involved in cell migration and angiogenesis, was shown to be associated with tumor development (44,45).…”

Towards molecular mechanisms regulating the expression of galectins in cancer cells under microenvironmental stress conditions

“…Indeed, the promoter region of chimeric type galectin-3 gene contains binding sites for the transcription factor HIF-1, which drives hypoxia-induced galectin-3 mRNA and protein expression, as observed in HeLa cells and mouse embryonic fibroblasts from HIF-1a wild-type, but not HIF-1a null mice [90]. The expression of galectin-3 gene was also strongly upregulated by hypoxia in the murine melanoma cell line BF-F10 [91]; however, this effect could be cell-specific because subsequent studies revealed no significant changes in five out of six human melanoma cell lines [92]. It is interesting to note that the combined hypoxia-induced upregulation of galectin-3 and epidermal growth factor receptor has been proposed to enhance the invasive potential of tumor cells that are exposed to stressed microenvironmental conditions [93].…”

Hypoxia and MITF control metastatic behaviour in mouse and human melanoma cells

“…Bhlhb2 is induced by hypoxia and represses MITF expression Transcription factors Bhlhb2, Sap30, Atf3 and Mxi1 were reported to be regulated upon exposure of B16 melanoma cells to hypoxic conditions (Olbryt et al, 2006). Therefore, we examined the effect of cobalt or hypoxia on these transcription factors.…”