Study of the genes correlated with cyst calcification in patients with cystic echinococcosis

Abstract

To explore the genes (biomarkers) correlated with cyst calcification in patients with cystic echinococcosis (CE), and to provide the evidence for the judgment on the patients' prognosis at molecular level. The liver tissues from 32 patients with liver CE (10 cases for mRNA microarray and 22 cases for real-time PCR analysis) and 11 patients with hepatic cystadenoma were collected from three hospitals in Ningxia from June, 2013 to December, 2014. A comparison of the different gene-expressions between five patients with calcified lesions and five cases with no calcification was carried out using Significant Analysis of Microarrays (SAM) to select a subset of differentially expressed genes (DEGs) . Fold-change analysis was used to assess the changes of the expression quantity in the same genes between two groups. The verification was conducted among the liver tissues from 22 patients with liver CE (11 in the group of calcified or 11 in that of non-calcified) by real-time quantitative PCR (RT-qPCR). With GAPDH as a reference-gene and the liver tissues from 11 cases with hepatic cystadenoma as standardized control groups, the relative expressions of galecitin-4 (LGALS4) and acid ceramidase (ASAH1) in patients with calcified and non-calcified were calculated, respectively. The differences between two groups were compared using t'-test. Five screened genes presented siginificantly different expressions all had showed the low-regulated expressions in the calcified group, with the most distinct low-regulation of LGALS4 and ASAH1 whose fold changes were 0.008 8, and 0.020 3, respectively. The verification by RT-qPCR illustrated that the relative expression of LGALS4 was showed at level of 0.49±0.27 amongst patients with calcified, and at level of 2.70±2.61 amongst non-calcified individuals,,indicating significant differences between two groups (t=-2.59, P=0.026); while the ASAH1 was relatively expressed at levels of 1.36±0.33 and of 1.68±0.67 amongst patients with calcified and non-calcified, respectively, showing insignificant changes statistically (t=-1.44, P=0.167). In the non-calcified group, both LGALS4 and ASAH1 genes expression quantities had a small fluctuation range, but with positively correlated trend (r=0.91, P=0.001), which indicated that a patient with the low LGALS4 expression quantity also had a relative low level of ASAH1 expression quantity. Low expression quantity of LGALS4 and ASAH1 genes in patients with CE in the calcification might be potential biomarker for an indication of the disease self-healing.