Circulating Biomarkers for the Detection of Human Liver Diseases

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Hepatocellular Carcinoma (HCC) is the third most common cause of cancer-related deaths worldwide. The risk of liver fibrosis and HCC increases significantly in hepatitis C virus (HCV) carriers with obesity and diabetes, which is a rising trend in the USA. Thus, HCC represents a wide-ranging public health issue. Our recent studies have revealed a positive correlation between overexpression of doublecortin-like kinase (DCLK1) and cancers of the liver, colon, intestine and pancreas. Recently, we have demonstrated that increased expression of DCLK1 in patients with cirrhosis and HCC. Furthermore, we demonstrated that DCLK1 expression tends to increase during progression of liver diseases such as cirrhosis and HCC. Downregulation of DCLK1 resulted in marked reduction of HCC cell proliferation and tumor-like growth in immunodeficient mice. Our studies indicate that DCLK1-affected biological processes in the pancreas and colon cancers including epithelial-to- mesenchymal transition (EMT) and cMYC pathways. For example, knockdown of DCLK1 results in marked upregulation of tumor-suppressor miRNAs (let-7a, miR-200, miR-144, and miR-145/143) with a concomitant decrease in cMYC, ZEB1/ZEB2, KRAS, NOTCH1, VEGFR1 and 2, and pluripotency factors OCT4, SOX2, NANOG and KLF4. Thus, DCLK1 appears to be a well-justified targets for anti-tumor treatment and is a potential prognostic biomarker for detecting/identifying/differentiating various stages of cirrhosis (based on Child-Pugh Score A – C) and HCC. Furthermore, several miRNAs (miR-21, miR-199a, and miR-301) are upregulated in cirrhosis and HCC, correlated with diseases outcomes. Furthermore these miRNAs are known to regulate/induce EMT and oncogenesis. Based on these observations, we hypothesize that DCLK1 and miRNAs are upregulated and can be detected in plasma of patients with HCC, and can be a biomarker for the detection of cirrhosis and HCC. The expression of DCLK1 and miRNAs will be compared to AFP-L3 levels in patients with fibrosis, cirrhosis and HCC. Here we will collect blood from 4 groups of patients – healthy controls, patients with fibrosis (but non-cirrhotic and non-HCC; classified based on FIB4 scoring), cirrhosis (non-HCC; Child-Pugh A – C) and HCC (either Child A, B or C). Samples will be collected at OKC VAMC (test cohort) and also at VA St. Louis Health Care System (validation cohort). We will test the hypothesis with the following specific aims. Aim 1. Identify candidate miRNAs- regulating EMT in the blood stream of patients with liver fibrosis or HCC. We will isolate total miRNAs from the plasma (collected from clinically defined fibrosis, cirrhosis and HCC) and perform microarray analysis to identify various miRNAs upregulated that have been associated with the regulation of EMT, in patients with liver diseases. We will also determine expression of specific miRNAs regulated by DCLK1. Aim 2. Determine whether plasma levels of DCLK1 are associated with the development of HCC. We will employ enzyme- linked immunosorbent assay (ELISA) (commercially available) to detect DCLK1 in patients' plasma (fibrosis, various stages of cirrhosis and HCC). We will also determine whether DCLK1 is increased in patients with cirrhosis and/or HCC compared to healthy controls. We will also estimate the plasma AFP-L3 levels in all the study subjects and compare it with DCLK1 and miRNA levels. Aim 3. To determine the signaling pathways that regulate EMT and metastasis, and stemness of circulating tumor cells isolated from HCC patients. Here we will isolate circulating cancer cells (from HCC patients) and determine their EMT signature, DCLK1 and miRNA status, and their clogenicity, migration and invasion capabilities. Successful completion of these studies will provide a new direction to combat HCC at an early stage. As 78% of the VA patients with liver diseases are diagnosed with HCC (median survival of 4.5–9.2 months), early detection of HCC by our methods will help the VA clinicians to decide early treatment strategies to increase the survival of the veterans.