Apoptosis-stimulating protein of p53-2 (ASPP2) induces apoptosis by promoting the expression of pro-apoptotic genes via binding to p53 or p73; however, the exact mechanisms by which ASPP2 induces apoptotic death in hepatoma cells are still unclear. Here, we show that the transient overexpression of ASPP2 induces autophagic apoptosis in hepatoma cells by promoting p53- or p73-independent C/EBP homologous protein (CHOP) expression. CHOP expression decreases the expression of Bcl-2; this change releases Beclin-1 from cytoplasmic Bcl-2-Beclin-1 complexes and allows it to initiate autophagy. However, transient overexpression of Beclin-1 can induce autophagy but not apoptosis. Our results show that ASPP2 induces the expression of damage-regulated autophagy modulator (DRAM), another critical factor that cooperates with free Beclin-1 to induce autophagic apoptosis. The effect of CHOP on the translocation and sequestration of Bcl-2 in the nucleus, which requires the binding of Bcl-2 to ASPP2, is also critical for ASPP2-induced autophagic apoptosis. Although the role of nuclear ASPP2–Bcl-2 complexes is still unclear, our results suggest that nuclear ASPP2 can prevent the translocation of the remaining Bcl-2 to the cytoplasm by binding to Bcl-2 in a CHOP-dependent manner, and this effect also contributes to Beclin-1-initiated autophagy. Thus, CHOP is critical for mediating ASPP2-induced autophagic apoptosis by decreasing Bcl-2 expression and maintaining nuclear ASPP2–Bcl-2 complexes. Our results, which define a mechanism whereby ASPP2 overexpression induces autophagic apoptosis, open a new avenue for promoting autophagy in treatments to cure hepatocellular carcinoma.

This study was carried out to evaluate the effects of a Huaier polysaccharide (TP-1) on the tumor growth and immune function in hepatocellular carcinoma (HCC) H22-based mouse in vivo. Results showed that TP-1 was capable of repressing transplanted H22 solid hepatic tumor cell growth in vivo, prolonging the live time of mice bearing ascetic H22 tumors, and repressing the pulmonary metastasis of H22-bearing mice. Moreover, the relative weight of immune organ (spleen and thymus) and lymphocyte proliferation were improved after TP-1 treatment. Furthermore, the treatment with TP-1 could promote immune-stimulating serum cytokines, such as IL-2 and IFN-γ, but inhibit immune-suppressing serum cytokines IL-10 secretion in H22-bearing mice. Besides, the percentage of CD4+ T cells and NK cells was increased, whereas the number of CD8+ T cells decreased in tumor-bearing mice following TP-1 administration. In addition, this compound displayed little toxic effects to major organ of tumor-bearing mice at the therapeutic dose, such as the liver and kidney. This experimental finding suggested that TP-1 exhibited prominent antitumor activities in vivo via enhancement of host immune system function in H22 tumor-bearing mice. This product could be developed individually as a safe and potent biological response modifier for HCC therapy.

No abstract

The role of cancer stem cells (CSCs) in inducing the recurrence of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) remains unclear. Here, we found that a dramatic increase in plasma vascular endothelial growth factor (VEGF) and an induction of local CD133+ CSCs are associated with early HCC recurrence, suggesting that VEGF expression and tumour stemness contribute to the relapse. In vitro studies demonstrated that VEGF, via activation of VEGFR2, increased the number of CD133+ CSCs and enhanced their capacity for self-renewal by inducing the expression of Nanog. In vivo studies further demonstrated that VEGF-treated CD133+ CSCs formed tumours larger than those developing from unstimulated cells and VEGF pre-treatment increased the tumorigenic cell frequency of primary HCC cells dependently on the presence of Nanog and VEGFR2. In HCC tissue derived from patients with early recurrence, almost all CD133+ cells were Nanog and p-VEGFR2 positive, suggesting that activation of VEGFR2 is critical for RFA-induced tumour stemness in HCC. In summary, RFA-induced VEGF promotes tumour stemness and accelerates tumourigenesis in HCC in a manner dependent on Nanog and VEGFR2, which is valuable for the prediction of HCC recurrence after RFA and the development of novel therapeutics.

No abstract

Astrocyte elevated gene-1 (AEG-1) is an important force in the development and progression of hepatocellular carcinoma (HCC). To extend our study, we examined here the role of AEG-1 in anti-metastatic effects of Huaier polysaccharide (HP) on the human HCC MHCC97-H cell line. AEG-1 shRNA contributed to the anti-proliferation effect of HP on MHCC97-H cells. Furthermore, results of Transwell insert chambers showed that low expression of AEG-1 could effectively facilitate HP to suppress MHCC97-H cell migration and invasion. We achieved this by reducing phosphoinositide 3-kinases (P13K) and phosphorylated Akt (pAkt) expression as well as enhancing natural killer (NK) cell activity. Taken together, our data strongly suggested that AEG-1 shRNA could block the carcinogenesis and progression of MHCC97-H cells and highlight the therapeutic potential of HP in HCC treatment, at least by part, by inhibiting the activation of the PI3K/Akt pathway and enhancing the NK cell-mediated immune response. These findings may provide a new strategy for HCC treatment.

Astrocyte elevated gene-1 (AEG-1) is involved in important biological processes including cell invasion, metastasis, and carcinogenesis. However, its clinical significance has remained largely unknown in hepatocellular carcinoma. Here, specimens from 144 patients with hepatocellular carcinomas in Beijing and Heilongjiang regions were investigated by immunohistochemical staining for AEG-1, vimentin, and E-cadherin expressions. A clinicopathological study revealed that AEG-1 expression level in tumor cells was significantly correlated with TNM stage (P = 0.001) and Edmonson grade (P < 0.0001). In addition, AEG-1, vimentin, and E-cadherin (epithelial-mesenchymal transition (EMT) biomarker) expressions were correlated with each other. These findings suggest that AEG-1 may be an epithelial-mesenchymal transition-associated biomarker in human hepatocellular carcinoma and play important roles in the progression of hepatocellular carcinoma. In addition, the AEG-1 gene is a potential target for elimination of hepatocellular carcinoma in the future.

Radiofrequency ablation (RFA) represents a valuable choice in hepatocellular carcinoma (HCC); however, local recurrence of HCC is common after RFA. Here, 20 primary HCC patients treated by RFA were enrolled. Before (termed 0d) and after RFA treatment for 1 and 7 days (termed 1d and 7d, respectively), plasma and noncancerous tissue were collected. ELISA assay showed that plasma C-X-C motif chemokine 10 (CXCL10) was increased in ten patients (type I patients) but decreased in the other 10 patients (type II patients). The mean interval for HCC recurrence in type I patients was less than the mean interval in type II patients. Interestingly, a significant negative correlation between interval for HCC recurrence and fold change of plasma CXCL10 (1d/0d or 7d/0d) was identified, suggesting that RFA-induced CXCL10 is associated with earlier HCC recurrence. Immunofluorescence assay showed that the receptor of CXCL10, chemokine (C-X-C motif) receptor 3 (CXCR3), was significantly increased in type I, but not type II, patients after RFA. In vitro assay demonstrated that CXCL10 stimulus increased the rate of CD133(+) cancer stem cells (CSCs) in HepG2 cells by binding to CXCR3 and then inducing c-Myc expression. Many studies have reported that induction of CD133(+) CSCs contributes to HCC recurrence. Thus, CXCL10-increased CD133(+) CSCs by activating CXCR3/c-Myc pathway might accelerate HCC recurrence after RFA. These data might have potential implications for HCC therapy.