1. Metabolic reprogramming and angiogenesis in primary cutaneous Merkel cell carcinoma: expression of hypoxia‐inducible factor‐1α and its central downstream factors
- Author
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Heinz Kutzner, Monika Heinzel-Gutenbrunner, Peter Helmbold, Alexander Enk, Ferdinand Toberer, Wolfgang Hartschuh, and Holger A. Haenssle
- Subjects
Vascular Endothelial Growth Factor A ,0301 basic medicine ,Skin Neoplasms ,Angiogenesis ,Merkel cell polyomavirus ,Dermatology ,Pathogenesis ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Medicine ,biology ,business.industry ,Merkel cell carcinoma ,Hypoxia-Inducible Factor 1, alpha Subunit ,biology.organism_classification ,medicine.disease ,FLT4 ,Carcinoma, Merkel Cell ,030104 developmental biology ,Infectious Diseases ,Hypoxia-inducible factors ,030220 oncology & carcinogenesis ,Monocarboxylate transporter 4 ,biology.protein ,Cancer research ,Immunohistochemistry ,business - Abstract
Background Metabolic reprogramming and altered gene expression mediated by hypoxia-inducible factors play crucial roles during tumour growth and progression. Nevertheless, studies analysing the expression of hypoxia-inducible factor-1α and its downstream targets in Merkel cell carcinoma (MCC) are lacking but are warranted to shed more light on MCC pathogenesis and to potentially provide new therapeutic options. Objectives To analyse the immunohistochemical expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor-A (referred to as VEGF throughout the manuscript), VEGF receptor-2 (VEGFR-2), VEGF receptor-3 (VEGFR-3), glucose transporter-1 (Glut-1), monocarboxylate transporter 4 (MCT4) and carbonic anhydrase IX (CAIX) in primary cutaneous MCC. Methods The 16 paraffin-embedded primary cutaneous MCCs (Merkel cell polyomavirus (McPyV) positive/negative: 11/5) were analysed by immunohistochemistry, namely HIF-1α, VEGF, VEGFR-2 (KDR), VEGFR-3 (FLT4), Glut-1, MCT4 and CAIX. An established quantification score (QS) was applied to quantitate the protein expression by considering the percentage of positive tumour cells (0: 0%; 1: up to 1%; 2: 2-10%; 3: 11-50%; 4: >50%) in relation to the staining intensity (0: negative; 1: low; 2: medium; 3: strong). Results HIF-1α was expressed in all MCCs and predominantly found at the invading edges of tumour margins. The HIF-1α downstream factors Glut-1, MCT4 and CAIX were expressed in 13 of 16 MCC (81%), 14 of 16 MCC (88%) and 16 of 16 MCC (100%), respectively. Interestingly, VEGF and VEGFR-2 were not expressed in tumour cells, whereas VEGFR-3 was expressed in all MCCs. HIF-1α was expressed significantly stronger in McPyV+ tumours (QS: 10.36 ± 2.41) than in McPyV- tumours (QS: 5.40 ± 1.34; P = 0.002). Similarly, VEGFR-3 was also expressed significantly stronger in McPyV+ tumours (QS: 10.00 ± 2.52) than in McPyV- tumours (QS: 5.40 ± 3.43, P = 0.019). Conclusions Our data provide first evidence for a role of HIF-1α in induced metabolic reprogramming contributing to MCC pathogenesis. The metabolic signatures of McPyV+ and McPyV- tumours seem to show relevant differences.
- Published
- 2020
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