Variation in dermcidin expression in a range of primary human tumours and in hypoxic/oxidatively stressed human cell lines

Abstract

Dermcidin acts as a survival factor in a variety of cancer cell lines under hypoxia or oxidative stress. The aim of this study was to evaluate dermcidin expression in cell lines following simulation of tumour microenvironmental conditions and in a range of primary tumours. Tumour tissues were collected from patients with oesophageal (28 samples), gastric (20), pancreatic (five), bile duct (one) and prostatic (52) carcinomas as well as 30 benign tissue samples, for assessment of dermcidin mRNA levels using real-time PCR. Dermcidin expression was assessed in prostatic and pancreatic cancer cell lines, with and without induction of hypoxia or oxidative stress. Dermcidin mRNA expression was very low or absent in both unstressed and stressed prostate cell lines. None of the primary prostate tissue, benign or malignant, expressed dermcidin mRNA. Only two (4%) of the gastro-oesophageal cancer samples expressed moderate quantities of dermcidin mRNA. However, three (60%) of the pancreatic cancer samples and the single cholangiocarcinoma specimen had moderate/high levels of dermcidin expression. Of the two pancreatic cancer cell lines, one expressed dermcidin moderately but neither showed a response to hypoxia or oxidative stress. Expression of dermcidin in human primary tumours appears highly variable and is not induced substantially by hypoxia/oxidative stress in cell line model systems. The relationship of these findings to dermcidin protein levels and cell survival remains to be determined.

Figure 1

Outline of the dermcidin gene and the processing of its protein products (aa=amino acids). For DCD amino acid sequences see (Lowrie et al, 2006). (First appeared in Curr Opin Clin Nutr Metab Care Vol 11(3), pp 208–213 (2008) reproduced with kind permission).

Figure 2

Dermcidin nucleotide sequence. ↑ denotes site of an intron. DCD real-time PCR primer target singly underlined and probe target doubly underlined. PIF-core peptide nucleotide sequence in bold. Start and stop codons are shown in upper case.