Downregulation of sorting nexin 10 is associated with overexpression of miR-30d during liver cancer progression in rats.

As of 2012, liver cancer was the second leading cause of death worldwide, and hepatocellular carcinoma is the most common primary cancer of the liver. The identification of molecules that might be molecular markers or therapeutic targets is urgently needed to improve clinical management. Based on a microarray analysis performed in our laboratory, we selected six genes-namely, ANXA2, DYNLT1, PFKP, PLA2G7, KRT19, and SNX10-as candidates for validation as tumor markers of liver cancer in a rat model. Their patterns of overexpression in preneoplastic lesions and established tumors at 10 different time points between 24 h and 18 months were analyzed to identify putative tumor markers for further studies. We validated the microarray results by quantitative reverse transcription polymerase chain reaction, which revealed high transcriptional expression for five of the genes, consistent with their high protein expression during cancer progression reported in the literature. However, studies of the association of sorting nexin 10 with different types of cancer are limited, prompting further study. The characterization of sorting nexin 10 in preneoplastic lesions and established tumors revealed messenger RNA overexpression and a simultaneous decrease in sorting nexin 10 protein expression. A group of microRNAs related to sorting nexin 10 messenger RNA were selected based on a data analysis conducted using miRDB and microrna.org . An analysis of the expression of these microRNAs revealed an increase in the transcription of microRNA-30d whenever the sorting nexin 10 protein was downregulated. These results suggest that sorting nexin 10 is a potential liver cancer marker exhibiting characteristics of a putative suppressor protein that is likely regulated by microRNA-30d.

The transmembrane transporter ABCC3 participates in liver cancer progression and is a potential biomarker.

The poor prognosis, few available treatment options, and multidrug resistance present in hepatocellular carcinoma are major problems, and new early biomarkers are needed to reduce the liver cancer death rate. ATP-binding cassette sub-family C member 3 (Abcc3) is overexpressed in different cancers and is associated with multidrug resistance and a carcinogenic stem cell phenotype. We present evidence for the first time that ABCC3 is a potential sanguine biomarker and anticancer target in hepatocellular carcinoma. Abcc3 mRNA expression was elevated in liver nodules and tumors in rat hepatocarcinogenesis model. Accordingly, the ABCC3 protein was preferentially overexpressed within the nodules and tumors during hepatocellular carcinoma progression and was secreted into the bloodstream of rat hepatocarcinogenesis model. The ABCC3 protein was expressed in human hepatoma cells and, importantly, was also present in HepG2- and Huh7-conditioned media. Furthermore, ABCC3 was overexpressed in human hepatocellular carcinoma. This report is the first to describe liver overexpression of Abcc3 during the cancer initiation, promotion, and progression periods in rat hepatocarcinogenesis model and in human hepatocellular carcinoma.

DNA methyltransferases 3a and 3b are differentially expressed in the early stages of a rat liver carcinogenesis model.

Carcinogenesis is driven by the accumulation of mutations and abnormal DNA methylation patterns, particularly the hypermethylation of tumor­suppressor genes. Changes in genomic DNA methylation patterns are established by the DNA methyltransferases (DNMTs) family: DNMT1, DNMT3a and DNMT3b. The DNMTs are known to be overexpressed in tumors. However, when the DNMTs expression profile is altered in earlier stages of carcinogenesis remains to be elucidated. The resistant hepatocyte model (RHM) allows the analysis of the hepatocellular carcinoma (HCC) from the formation of altered cell foci to the appearance of tumors in rats. To investigate the DNMTs expression in this model, we first observed that timp3, rassf1a and p16 genes became methylated during cancer development by methylation­specific PCR (MSP) and the bisulphate sequencing PCR (BSP) of timp3. The differential expression at the RNA and protein level of the three DNMTs was also assessed. dnmt1 expression was higher in tumors than in normal and early cancer stages. However, no evident overexpression of the enzyme was identified by immunohistochemistry. By contrast, DNMT3a and DNMT3b were consistently subexpressed in tumors. In the present study, we report a carcinogenesis model that does not feature the overexpression of DNMT1 but exhibits a transient expression of DNMT3a and DNMT3b.