Primary and Secondary micro-RNA Modulation the Extrinsic Pathway of Apoptosis in Hepatocellular Carcinoma

Abstract

Abstract-One of the most common malignant liver diseases is hepatocellular carcinoma, which has a high recurrence rate and a low five-year survival rate. It is very heterogeneous both in structure and between patients, which complicates the diagnosis, prognosis and response to treatment. In this regard, an individualized, patient-centered approach becomes important, in which the use of mimetics and hsa-miRNA inhibitors involved in the pathogenesis of the disease may be determinative. From this point of view hsa-miRNAs are of interest, their aberrant expression is associated with poor prognosis for patients and is associated with tumor progression due to dysregulation of programmed cell death (apoptosis). However, the effect of hsa-miRNA on tumor development depends not only on its direct effect on expression of genes, the primary targets, but also on secondary targets mediated by regulatory pathways. While the former are actively studied, the role of secondary targets of these hsa-miRNAs in modulating apoptosis is still unclear. The present work summarizes data on hsa-miRNAs whose primary targets are key genes of the extrinsic pathway of apoptosis. Their aberrant expression is associated with early disease relapse and poor patient outcome. For these hsa-miRNAs, using the software package ANDSystem, we reconstructed the regulation of the expression of secondary targets and analyzed their impact on the activity of the extrinsic pathway of apoptosis. The potential effect of hsa-miRNAs mediated by action on secondary targets is shown to negatively correlate with the number of primary targets. It is also shown that hsa-miR-373, hsa-miR-106b and hsa-miR-96 have the highest priority as markers of hepatocellular carcinoma, whose action on secondary targets enhances their anti-apoptotic effect.

Keywords: ANDSystem; extrinsic pathway of apoptosis; hepatocellular carcinoma; microRNA; primary and secondary targets; programmed cell death; regulatory pathways.

Fig. 1.

Scheme of components of the external pathway of apoptosis and miRNAs involved in its regulation in HCC. Designations: BID (Bcl-2 homolog (BH)3-only protein, BH3 interacting domain death agonist), CD95/Fas/APO-1 (Death receptor), CASP-3, -8 (caspase-3, -8), cFLIP / CFLAR (cellular FADD-like interleukin-1b-converting enzyme (FLICE)-inhibitory protein/CASP8 and FADD like apoptosis regulator), DR-4 (death receptor 4), FADD (Fas associated via death domain), FAP1 (Fas-associated phosphatase-1), FASLG (FAS ligand), NF-κB (Nuclear factor kappa-B), NEMO (NF-kB essential modulator/IκB kinase γ), TRAIL (TNF-related apoptosis-inducing ligand). Extrinsic pathway—external pathway of apoptosis, Intrinsic pathway—internal pathway of apoptosis. Black arrows - activation of the function of the corresponding protein or expression of its gene, arrows with a blunt end—blockade. Proteins whose gene expression is controlled by miRNAs are marked in red, onco-miRNAs are highlighted in blue, suppressors are highlighted in purple. Colored arrows pointing up indicate an increased level of expression of the corresponding miRNAs in HCC, arrows pointing down indicate a reduced level. Icon indicates an interaction between the marked proteins.

Fig. 2.

Regulatory expression pathways for miRNA secondary target genes constructed using the ANDSystem. Designations: BCL2 (B-cell lymphoma 2), CCL2 (CC Motif Chemokine Ligand 2), CD (Crohn’s disease, receptor), CD40L (CD40 ligand), CFLAR (CASP8 and FADD like apoptosis regulator), DDIT3 (DNA damage induced transcript 3), FASLG (FAS ligand), FETA (α-fetoprotein), FOXO1 (Forkhead box O protein 1), IL1B/8 (Interleukin 1B/8), ITCH (Itchy E3 ubiquitin-protein ligase), JUN (proto-oncogene, AP-1 transcription factor subunit), M3K1 (Mitogen-activated protein kinase kinase kinase 1), MK14 (Mitogen-activated protein kinase 14), hsa-miR (microRNA Homo sapiens ), NF1 (Nuclear factor 1), NFKB1 (Nuclear factor kappa-B 1), PTPN13/PTN13 (Tyrosine-protein phosphatase nonreceptor type 13), SP1 (Specificity protein 1, transcription factor), STAT3 (Signal transducer and activator of transcription 3), TGFB1 (Transforming growth factor beta 1), TET1 (Ten-eleven translocation 1), TNFRSF10A/TR10A (Tumor necrosis factor receptor superfamily 10A), UCRI (Ubiquinol-cytochrome C reductase iron-sulfur subunits), VEGFA (Vascular endothelial growth factor receptor), ‘canonical’ nf-kappab pathway

Fig. 3.

The relationship between the number of miRNA targets, the expression of which is increased in HCC, and their total effect (Ea) to the external pathway of apoptosis through regulatory pathways. Pairwise correlation coefficient R amounted to –0.86 (P = 0.025).