Highly upregulated in liver cancer noncoding RNA is overexpressed in hepatic colorectal metastasis

Abstract

BACKGROUND: The highly upregulated in liver cancer (HULC) gene transcribes to an mRNA-like noncoding RNA (ncRNA) by the RNA polymerase II and processed by capping, splicing and polyadenylation. It is specifically expressed in the hepatocytes with striking upregulation in hepatocellular carcinoma (HCC). OBJECTIVES: To study the expression levels of HULC in normal colorectal samples, primary colorectal carcinomas and in secondary tumors formed from colorectal carcinomas that metastasize to either the liver or the lymph nodes, taken from the same patients. Also a panel of carcinoma cell lines is tested for HULC expression. BASIC METHODS: Semiquantitative reverse transcriptase-PCR technique is used to detect for HULC expression in study specimens and cell lines. RESULTS: Consistent with the previous report, HULC is neither expressed in primary colorectal carcinomas samples nor in their normal counterparts. We show for the first time those colorectal carcinomas that metastasize to the livers but not to lymph nodes experience an upregulation of HULC ncRNA in all the samples tested (n= 8), with a strong-to-moderate expression in six out of eight. Moreover HULC is not expressed in the majority of carcinoma cell lines tested and also in samples of normal bladder and bladder cancers of various grades. We also show that HULC ncRNA is upregulated in two hepatocellular carcinoma cell lines producing HBV relevant to their parental lines that do not produce HBV. CONCLUSION: Our results presented here indicate that HULC expression is not confined to HCC, but also to those colorectal carcinomas that metastasize to the liver.