Toll-like receptor transcriptome in the HPV-positive cervical cancer microenvironment

Abstract

The human papillomavirus (HPV) directly infects cervical keratinocytes and interferes with TLR signalling. To shed light on the effect of HPV on upstream receptors, we evaluated TLRs 1-9 gene expression in HPV-negative normal and HPV-positive pre-malignant and malignant ex vivo cervical tissue. Quantitative real-time polymerase chain reaction was performed separately for epithelial and stromal tissue compartments. Differences in gene expression were analyzed by the Jonckheere-Terpstra trend test or the Student's t-test for pairwise comparison. Laser capture microdissection revealed an increase in TLR3 and a decrease in TLR1 mRNA levels in dysplastic and carcinoma epithelium, respectively. In the stroma, a trend of increasing TLR 1, 2, 5, 6, and 9 mRNA levels with disease severity was found. These findings implicate the involvement of TLR3 and TLR1 in early and late cervical carcinogenesis, respectively, suggesting that stromal upregulation of TLRs may play a role in cervical disease progression.

Figure 1

TLR gene expression in normal, dysplastic and carcinoma ex vivo cervical tissue. Scatterplot indicating relative TLR gene expression levels (logged) in normal, dysplastic and carcinoma samples in the epithelium (a) and stroma (b) compartment. Horizontal bars show the average expression levels per group for each gene. Asterisks show significant expression differences from normal samples according to the Student's t-test for pairwise comparisons. Reported average relative expression values for each gene in both tissue compartments (c), values calculated according to 2^−ΔCT ∗ 1,000. Fold change values for TLRs in dysplastic and carcinoma samples (d). Significant fold change values according to the Student's t-test for pairwise comparison of two types are indicated with a thick border, and genes with significant upregulation trends according to the Jonckheere-Terpstra test are shaded gray.

Figure 2

Overall gene expression models for ex vivo dysplastic (a) and carcinoma (b) cervical epithelium and stroma. Genes presented from the current analysis as either up or down-regulated compared to HPV-negative, normal cervical tissue. Italicized genes are based on data we reported previously [19]. In addition to the data presented, trend analyses also revealed a significant up-regulation of TLRs 1, 2, 5, 6, and 9 in the stroma with disease severity.