Clinical significance of serum circulating insulin-like growth factor-1 (IGF-1) mRNA in hepatocellular carcinoma

HBx/WDR5 enhances IGF-1 transcription in hepatocellular carcinoma cells and promotes recruitment, infiltration, and activity of Treg cells

HBV X protein (HBx), the smallest open reading frame in the hepatitis B virus (HBV) genome, can promote hepatocellular carcinoma (HCC) tumorigenesis by activating the expression of multiple oncogenes through inducing epigenetic alterations and interacting with the underlying transcriptional machinery. HBV non-infected HepG2 and Huh7 cells were transfected with HBx expression plasmids. The transcriptional, protein expression, and secretion levels of IGF-1 were detected by RT-qPCR, western blot, and ELISA, respectively. ChIP-qPCR was used to analyze the binding proteins on the IGF-1 gene. A co-culture system of HCC and Treg cells was designed using Transwell chambers. IGF-1 mRNA, protein, and secretion levels were increased in HepG2 and Huh7 cells exogenously expressing HBx. HBx was able to enter the nucleus and interact with the enhancer region of the IGF-1 gene. Levels of WDR5 and H3K4me1, which bind to the enhancer region of the IGF-1 gene, were also increased in HepG2 and Huh7 cells ectopically expressing HBx. Knockdown of WDR5 counteracted the upregulation of IGF-1 mRNA and protein levels by HBx. In the cell co-culture system, HBx/IGF-1 signaling in HCC cells promoted Treg cells expansion, IL-10 secretion, and infiltration, which was blocked by the IGF-1R inhibitor picropodophyllin. HBx/WDR5 promoted IGF-1 transcription in HCC cells through enhancers. HBx could promote Treg cell recruitment, infiltration, and activity by enhancing IGF-1 expression. IGF-1/IGF-1R signaling plays an important role in the communication between HCC cells and Treg cells. Targeting WDR or IGF-1/IGF-1R would be beneficial for the treatment of HCC.

Association between the HGF/c‑MET signaling pathway and tumorigenesis, progression and prognosis of hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is one of the most aggressive and lethal malignancies with a rising incidence, and is characterized by rapid progression, frequent metastasis, late diagnosis, high postoperative recurrence and poor prognosis. Therefore, novel treatment strategies for HCC, particularly advanced HCC, are urgently required. The hepatocyte growth factor (HGF)/c‑mesenchymal‑epithelial transition receptor (c‑MET) axis is a key signaling pathway in HCC and is strongly associated with its highly malignant features. Available treatments based on HGF/c‑MET inhibition may prolong the lifespan of patients with HCC; however, they do not achieve the desired therapeutic effects. The aim of the present article was to review the basic knowledge regarding the role of the HGF/c‑MET signaling pathway in HCC, and examine the association between the HGF/c‑MET signaling pathway and the tumorigenesis, progression and prognosis of HCC.

Preoperative Serum Insulin-Like Growth Factor 1 Level as a Prognostic Factor in Patients Undergoing Hepatic Resection for Hepatocellular Carcinoma

In this study, preoperative serum levels of insulin-like growth factor 1 (IGF-1) were determined in 216 hepatocellular carcinoma (HCC) patients who underwent hepatic resection to investigate a possible contribution of IGF-1 to the increased risk for HCC recurrence and mortality. During January 2010 and December 2013, 216 HCC patients receiving hepatectomy were recruited. The primary endpoint was the HCC recurrences within the 3-year follow-up. The secondary endpoint was all-cause mortality. The multivariate analyses with Cox regression model were applied to explore the clinical significance of IGF-1 serum levels and associated parameters on death and recurrence of HCC patients. The IGF-1 levels of included patients were determined, with a median value of 75.5 ng/mL (IQR, 40.3-93.0 ng/mL). The preoperative serum level of IGF-1 was negatively correlated with tumor size, Child-Pugh class, or tumor stage (P < 0.001 for all). In multivariate models comparing the first, second, and third quartiles with the fourth quartile of IGF-1, the levels of IGF-1 in Q1 and Q2 were associated with HCC recurrence, with an increased risk of 216% [hazard ratios (HR) = 3.16 (95% CI: 1.79-4.28)] and 106% [3.02 (1.36-3.11)]. Similarly, concentrations of IGF-1 in Q1 and Q2 were also related to all-cause mortality, with an increased recurrence risk of 238% [HR = 3.38 (95% CI: 1.85-4.36)] and 117% [3.02 (1.40-3.21)], respectively. Poor prognosis in HCC patients receiving hepatectomy could be indicated by low preoperative serum levels of IGF-1, which would be applied as a predictor.

Esculetin induces apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-mediated mitochondrial pathways

Esculetin (6,7-dihydroxycoumarin) is a coumarin derivative extracted from natural plants and has been reported to have anticancer activity. However, the mechanism by which esculetin prevents human hepatic cancer cell growth is still largely unknown. In this study, we investigated the effect of esculetin on human hepatocellular carcinoma (HCC) SMMC-7721 cells and explored the cell signal mechanism. Our data indicated that esculetin induced apoptosis in SMMC-7721 cells, which were supported by DAPI staining and Annexin V/PI staining. Meanwhile, esculetin increased the activities of caspase-3 and caspase-9, promoted bax expression, decreased bcl-2 expression, and triggered collapse of mitochondrial membrane potential, and increased cytochrome c release from mitochondria. In addition, the inactivation of IGF-1, PI3K, and Akt was observed after esculetin administration. Furthermore, pretreatment with IGF-1 before esculetin administration abrogated the pro-apoptotic effects of esculetin, while PI3K inhibitor increased the pro-apoptotic effects of esculetin. These results indicated that esculetin induced the apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-regulated mitochondrial dysfunction.

Cooperative effects of hepatitis B virus and TNF may play important roles in the activation of metabolic pathways through the activation of NF-κB

Elevated levels of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β are often observed in the sera of hepatitis B virus (HBV)-infected patients. It is well known that these cytokines activate nuclear factor-κB (NF-κB)-signaling, and are associated with endoplasmic reticulum (ER) stress. We investigated whether HBV or HBV X protein (HBx) enhanced the activation of NF-κB in the presence of TNF and/or IL-1β, and their effects on the expression of metabolic pathway‑associated genes. We examined whether HBV or HBx enhanced cytokine-induced activation of NF-κB in hepatocytes, using a reporter assay, in the presence or absence of TNF and/or IL-1β. The expression of insulin-like growth factor binding protein 1 (IGFBP1), one of the NF-κB target genes was also examined. The expression of metabolic pathway-associated genes in HepG2 and HepG2.2.15 cells in the presence or absence of TNF was evaluated by RT-qPCR. Human hepatocytes expressed TNF receptors and IL-1 receptors. NF-κB was activated by cooperation between HBx and TNF in human hepatocytes. We observed IGFBP1 expression in HBV infection and that a number of metabolic pathway-associated genes were upregulated in HepG2.2.15 cells, compared with HepG2 cells with or without TNF treatment. We observed the cooperative effects of HBV and TNF which enhanced the activation of NF-κB as well as upregulated the expression of metabolic pathway-associated genes in hepatocytes. These effects may be important in the development of HBV-associated metabolic syndrome.

Prognostic significance of serum insulin-like growth factor-1 in patients with hepatocellular carcinoma following transarterial chemoembolization

Insulin-like growth factor-1 (IGF-1) is an effective survival factor that is involved in the development and progression of various tumors. The aim of the present study was to investigate whether baseline serum IGF-1 levels are associated with time to progression (TTP) and overall survival (OS) in patients with hepatocellular carcinoma (HCC) who have undergone transarterial chemoembolization (TACE). A total of 145 patients with HCC who underwent TACE as an initial treatment were enrolled in the study. Baseline serum IGF-1 levels were detected using enzyme-linked immunosorbent assay (ELISA) kits. The patients were followed up for a median follow-up period of 47 months (range, 10.6-69.3 months). During the follow-up, 98 patients (76.6%) experienced disease progression and 59 patients (46.1%) succumbed. The serum IGF-1 level was found to be significantly associated with hepatitis infection status, Child-Pugh class, bilirubin level, tumor size and nodularity, vascular invasion and the Barcelona Clinic Liver Cancer (BCLC) stage. Multivariate analysis was conducted, which indicated that BCLC stage, vascular invasion and serum IGF-1 were independent risk factors for disease progression. When clinical factors were examined as potential independent risk factors for OS, only advanced BCLC stage and low serum IGF-1 levels were found to be significantly associated with poorer OS. These results suggest that serum IGF-1 may serve as a predictor of the prognosis of patients with HCC undergoing TACE.

Inflammation and insulin/IGF-1 resistance as the possible link between obesity and neurodegeneration

Obesity is a growing epidemic that contributes to several brain disorders including Alzheimer's, Parkinson's, and Huntington's diseases. Obesity could promote these diseases through several different mechanisms. Here we review evidence supporting the involvement of two recently recognized factors linking obesity with neurodegeneration: the induction of pro-inflammatory cytokines and onset of insulin and insulin-like growth factor 1 (IGF-1) resistance. Excess peripheral pro-inflammatory mediators, some of which can cross the blood brain barrier, may trigger neuroinflammation, which subsequently exacerbates neurodegeneration. Insulin and IGF-1 resistance leads to weakening of neuroprotective signaling by these molecules and can contribute to onset of neurodegenerative diseases.