Metabolic markers in relation to hypoxia; staining patterns and colocalization of pimonidazole, HIF-1α, CAIX, LDH-5, GLUT-1, MCT1 and MCT4

Abstract

BackgroundThe cellular response of malignant tumors to hypoxia is diverse. Several important endogenous metabolic markers are upregulated under hypoxic conditions. We examined the staining patterns and co-expression of HIF-1α, CAIX, LDH-5, GLUT-1, MCT1 and MCT4 with the exogenous hypoxic cell marker pimonidazole and the association of marker expression with clinicopathological characteristics.Methods20 biopsies of advanced head and neck carcinomas were immunohistochemically stained and analyzed. All patients were given the hypoxia marker pimonidazole intravenously 2 h prior to biopsy taking. The tumor area positive for each marker, the colocalization of the different markers and the distribution of the markers in relation to the blood vessels were assessed by semiautomatic quantitative analysis.ResultsMCT1 staining was present in hypoxic (pimonidazole stained) as well as non-hypoxic areas in almost equal amounts. MCT1 expression showed a significant overall correlation (r = 0.75, p < 0.001) and strong spatial relationship with CAIX. LDH-5 showed the strongest correlation with pimonidazole (r = 0.66, p = 0.002). MCT4 and GLUT-1 demonstrated a typical diffusion-limited hypoxic pattern and showed a high degree of colocalization. Both MCT4 and CAIX showed a higher expression in the primary tumor in node positive patients (p = 0.09 both).ConclusionsColocalization and staining patterns of metabolic and hypoxia-related proteins provides valuable additional information over single protein analyses and can improve the understanding of their functions and environmental influences.

Glucose deprivation increases monocarboxylate transporter 1 (MCT1) expression and MCT1-dependent tumor cell migration

“…As CD147 beyond MCT1 associates with a number of partners (including MCT4) to form supercomplexes, 39 additional and perhaps more indirect influences cannot be excluded. Furthermore, additional controls would be involved under hypoxia, [40][41][42] explaining why hypoxia can fail to induce or can even repress MCT1 expression in vivo 3,43 whereas it stimulates MCT1 expression in vitro 44 (Figure 2a), and why we detected increased MCT1 expression at early time points (Figure 2a, 24 h) whereas others did not find MCT1 induction upon a longer exposure to hypoxia (48 h). 5 Modulating ROS can indeed impact the response of MCT1 to hypoxia (Supplementary Figure 4A).…”

Hypoxia promotes production of neural crest cells in the embryonic head

“…Tissue hypoxia was assessed in chick embryos using pimonidazole, which forms immunologically detectable adducts in hypoxic cells (Arteel et al, 1995;Rademakers et al, 2011;Vukovic et al, 2001). In ovo cultured embryos were shown to be positive for pimonidazole at HH stages 9-10 (Fig.…”

Expression of Endogenous Hypoxia Markers in Vulvar Squamous Cell Carcinoma

“…GLUT-1 is a representative member of the glucose transporter family and is widely distributed in normal tissues such as erythrocytes and endothelial cells at the blood-brain barrier . GLUT-1 is involved in the metabolic adaptation of the cell to hypoxia by increasing the intracellular glucose supply, which might be regulated by HIF-1α (Rademakers et al, 2011). CA-9, one of the 15 carbonic anhydrase isoforms in humans, which is exclusively transactivated by HIF-1α, has recently emerged as one of the most promising endogenous hypoxia-related markers of cellular hypoxia (Kaluz et al, 2009).…”