Urolithin B suppresses tumor growth in hepatocellular carcinoma through inducing the inactivation of Wnt/β-catenin signaling

Consumption of dietary ellagitannins (ETs) has been proven to benefit multiple chronic health disorders including cancers and cardiovascular diseases. Urolithins, gut microbiota metabolites derived from ETs, are considered as the molecules responsible for these health effects. Previous studies have demonstrated that urolithins exhibit antiproliferative effects on prostate, breast, and colon cancers. However, as for hepatocellular carcinoma (HCC), it remains elusive. Herein, we aim to investigate the function of urolithin B (UB), a member of urolithins family, in HCC. The effects of UB on cell viability, cell cycle and apoptosis were evaluated in HCC cells, and we found UB could inhibit the proliferation of HCC cells, which resulted from cell cycle arrest and apoptosis. Furthermore, UB could increase phosphorylated β-catenin expression and block its translocation from nuclear to cytoplasm, thus inducing the inactivation of Wnt/β-catenin signaling. Using a xenograft mice model, UB was found to suppress tumor growth in vivo. In conclusion, our data demonstrated that UB could inhibit the proliferation of HCC cells in vitro and in vivo via inactivating Wnt/β-catenin signaling, suggesting UB could be a promising candidate in the development of anticancer drugs targeting HCC.     

Involvement of PPARγ in the antitumoral action of cannabinoids on hepatocellular carcinoma

Cannabinoids exert antiproliferative effects in a wide range of tumoral cells, including hepatocellular carcinoma (HCC) cells. In this study, we examined whether the PPARγ-activated pathway contributed to the antitumor effect of two cannabinoids, Δ9-tetrahydrocannabinol (THC) and JWH-015, against HepG2 and HUH-7 HCC cells. Both cannabinoids increased the activity and intracellular level of PPARγ mRNA and protein, which was abolished by the PPARγ inhibitor GW9662. Moreover, genetic ablation with small interfering RNA (siRNA), as well as pharmacological inhibition of PPARγ decreased the cannabinoid-induced cell death and apoptosis. Likewise, GW9662 totally blocked the antitumoral action of cannabinoids in xenograft-induced HCC tumors in mice. In addition, PPARγ knockdown with siRNA caused accumulation of the autophagy markers LC3-II and p62, suggesting that PPARγ is necessary for the autophagy flux promoted by cannabinoids. Interestingly, downregulation of the endoplasmic reticulum stress-related protein tribbles homolog 3 (TRIB3) markedly reduced PPARγ expression and induced p62 accumulation, which was counteracted by overexpression of PPARγ in TRIB3-knocked down cells. Taken together, we demonstrate for the first time that the antiproliferative action of the cannabinoids THC and JWH-015 on HCC, in vitro and in vivo, are modulated by upregulation of PPARγ-dependent pathways.     

Over expression of integrin α 5 β 1 in human hepatocellular carcinoma cell line suppresses cell proliferation in vitro and tumorigenicity in nude mice

Integrin 5 1 and 2 1 are the major integrin receptors in human hepatocytes. However, in human hepatocellular carcinoma cells it was found that the expression of integrin 5 1 was decreased and another integrin 6 1 increased. In this study, the SMMC7721 human hepatocellular carcinoma cells cotransfected or singlely transfected with integrin 5 and/or 1 cDNAs were established, and designated 5 1.6-7721, 5.3-7721, and 1.6-7721 cell lines, respectively. Transfection with cDNAs of integrin 5 and 1 subunits resulted in the overexpression of each integrin and modified biological properties, including a slowed growth rate, changes in the cell cycle from 15.5% of control cells in the G2/M phase to 12.1%, 9.6% and 9.4% in 5.3-7721, 1.6-7721, 5 1.6-7721, respectively, and a decrease in the Cell Mitosis Index from 1.6 in controls to 0.96, 0.95, and 0.72, and 34%, 28% and 52% derived from colony forming ability, respectively. Tumorigenicity was also tested in nude mice with inoculation of cells subcutaneously. Tumor masses growing in nude mice following inoculation with 1.6-7721,and 5 1.6-7721 cells weighed only 52% or 31% those of control cells. These results indicated that deletion or low expression of integrin 5 1 may play an important role in the development of hepatocellular carcinoma. Therefore, induction of expression of the integrin 5 1 in malignant cells could be a potential means of treating hepatocellular carcinoma.     

Up-regulation of E-cadherin and β-catenin in human hepatocellular carcinoma cell lines by sodium butyrate and interferon-α

Summary Human E-cadherin is a homophilic cell adhesion molecule and its expression is well preserved in normal human hepatocytes; a decrease in its expression has been observed in poorly differentiated hepatocellular carcinoma cells. We examined the alteration of E-cadherin and catenin expressions caused by differentiation inducers in human hepatocellular carcinoma cells. Hepatocellular carcinoma cell lines, HCC-T and HCC-M, were cultured with all-trans retinoic acid (ATRA), dexamethasone (DEX), sodium butyrate, and interferon-α. E-cadherin expression was only up-regulated by butyrate and interferon-α (IFN-α) in both cell lines, studied by means of fluorescence immunostaining and flow cytometry. The localization of E-cadherin staining was shown at their cell membrane. According to the increase in E-cadherin expression, β-catenin expression appeared at the cell membrane of both cell lines when treated with butyrate and IFN-α. Such an appearance was not observed when cells were treated with ATRA and DEX. Western blotting showed that α-and γ-catenin expression was not changed, while only the expression of β-catenin increased. β-Catenin oncogenic activation as a result of amino acid substitutions or interstitial deletions within or including parts of exon 3, which has been demonstrated recently, was not detected in these cell lines by direct deoxyribonucleic acid sequencing. These results suggest that the expression and interaction between E-cadherin and wild-type β-catenin are potentially modulated by butyrate and IFN-α, and that these two agents are potent inhibitors of hepatocellular carcinoma cell invasion and metastasis.     

p120-catenin suppresses proliferation and tumor growth of oral squamous cell carcinoma via inhibiting nuclear phospholipase C-γ1 signaling

p120-catenin (p120) serves as a stabilizer of the calcium-dependent cadherin-catenin complex and loss of p120 expression has been observed in several types of human cancers. The p120-dependent E-cadherin-β-catenin complex has been shown to mediate calcium-induced keratinocyte differentiation via inducing activation of plasma membrane phospholipase C-γ1 (PLC-γ1). On the other hand, PLC-γ1 has been shown to interact with phosphatidylinositol 3-kinase enhancer in the nucleus and plays a critical role in epidermal growth factor-induced proliferation of oral squamous cell carcinoma (OSCC) cells. To determine whether p120 suppresses OSCC proliferation and tumor growth via inhibiting PLC-γ1, we examined effects of p120 knockdown or p120 and PLC-γ1 double knockdown on proliferation of cultured OSCC cells and tumor growth in xenograft OSCC in mice. The results showed that knockdown of p120 reduced levels of PLC-γ1 in the plasma membrane and increased levels of PLC-γ1 and its signaling in the nucleus in OSCC cells and OSCC cell proliferation as well as xenograft OSCC tumor growth. However, double knockdown of p120 and PLC-γ1 or knockdown of PLC-γ1 alone did not have any effect. Immunohistochemical analysis of OSCC tissue from patients showed a lower expression level of p120 and a higher expression level of PLC-γ1 compared with that of adjacent noncancerous tissue. These data indicate that p120 suppresses OSCC cell proliferation and tumor growth by inhibiting signaling mediated by nuclear PLC-γ1.     

Sorafenib sensitizes hepatocellular carcinoma cell to cisplatin via suppression of Wnt/β-catenin signaling

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Systemic chemotherapy plays an important role in the treatment of patients with advanced liver cancer. However, chemoresistance to cisplatin is a major limitation of cisplatin-based chemotherapy in the clinic, and the underlying mechanism of such resistance is not fully understood. In this study, we found that nuclear accumulation of β-catenin was higher in cisplatin-resistant Huh7 cells than in Huh7 cells, indicating that Wnt signaling was activated in cisplatin-resistant cells. Wnt signaling inhibition increased cisplatin-induced growth inhibition in hepatoma cell. We further demonstrated that sorafenib could inhibit Wnt signaling in Huh7 cells and cisplatin-resistant Huh7 cells. Co-treatment with cisplatin and sorafenib was more effective in inhibiting cancer cell proliferation than cisplatin alone in vitro and in vivo, whereas Wnt3a (Wnt activator) treatment abrogated sorafenib-induced growth inhibition. These data demonstrated that sorafenib sensitizes human HCC cell to cisplatin via suppression of Wnt/β-catenin signaling, thus offering a new target for chemotherapy of HCC.     

Effects of ascorbic acid and ��-carotene on HepG2 human hepatocellular carcinoma cell line

Recent studies have demonstrated that vegetable rich diets have protective effects on the occurrence and prognosis of various cancers. In addition to dietary intakes, ascorbic acid and β-carotene are also taken as supplements. The aim of this study was to assess effects of ascorbic acid, β-carotene and their combinations on human hepatocellular carcinoma cell line HepG2. Ascorbic acid and β-carotene were applied to cells as plasma peak concentrations (70 and 8 μM, respectively) and their half concentrations (35 and 4 μM, respectively) for 24 and 48 h. Genotoxic and cytotoxic effects of ascorbic acid and β-carotene were evaluated by alkali single cell gel electrophoresis (SCGE), acridine orange/ethidium bromide staining patterns of cells (apoptosis and necrosis) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Results of the SCGE demonstrated that both ascorbic acid and β-carotene caused DNA damage on HepG2 which were also concordant to increased apoptosis and necrosis of cells. Increased TBARS values also demonstrated increased lipid peroxidation in these cells. Results of the present study demonstrates that when dietary intakes of ascorbic acid and β-carotene and their relevant achievable plasma level concentrations were considered, both ascorbic acid and β-carotene induce genotoxic and cytotoxic damage on HepG2 together with increased oxidative damage in contrast to their protective effect on healthy cells. This may be correlated to oxidative status and balance of ROS in hepatocellular carcinoma cells.     

Rce1 suppresses invasion and metastasis of hepatocellular carcinoma via epithelial-mesenchymal transition induced by the TGF-β1/H-Ras signaling pathway

Ras converting enzyme 1 (Rce1) plays an important role in invasion and metastasis of malignancy. However, the mechanism has not yet been fully explored in hepatocellular carcinoma (HCC). Primarily, we investigated the expression of Rce1 and H-Ras influence on patient prognosis through the clinical data. Further, we analyzed the regulatory effects of Rce1/H-Ras signal pathway on the epithelial–mesenchymal transition (EMT) in vitro and in vivo. Finally, we screened out the protein which bonds with Rce1 by CO-IP experiment to discuss the mechanism of Rce1 in EMT of HCC. This research revealed a significantly decreased expression of Rce1 in HCC compared with noncancerous tissues (p < .05). In contrast, H-Ras expression was increased in the tumor. The expression of them was a close association with the differentiation and tumor-node-metastasis (TNM) stage of the tumor (p < .001; p = .035, respectively) and Rce1 was an independent prognostic indicator (95%Cl: 0.193–0.821; p = .013). Through targeted regulation of Rce1 by cDNA or small interfering RNA, results show that the lower expression of Rce1 facilitated EMT and promoted the invasion and metastasis of HCC (p < .05). Furthermore, the CO-IP experiment unfolded that Rce1 could bond with farnesyltransferase-β (FNTB) which mediated the expression of H-Ras. Conclusions: Rce1 inhibits EMT via target regulation H-Ras and suppress the early invasion and metastasis of HCC. It may be a potential therapeutic target and prognostic indicator for HCC.     

In vitro secretion of transforming growth factor alpha (TGF-α): A comparison of the A431 cell line with three human oesophageal squamous cell carcinoma lines

Transforming growth factor alpha (TGF-) is a single chain polypeptide which exists in a variety of forms differing in molecular weight. These forms are variously present in normal and neoplastic cells. Of particular interest are TGF-'s well-known mitogenic properties. The transition from a normal to a neoplastic cellular state results from signalling defects that may depend upon,iter alia, abonormal levels of expression and secretion of TGF-. It is known that the secretion of TGF- may be enhanced appreciably by agents such as phorbol 12-myristate 13-acetate (PMA), serum factors and epidermal growth factor (EGF). Here, we compare the efficacy of these three agents in the elevation of TGF- secretion in the well studied A431 cell line with their previously undocumented efficacy in certain interesting, but little known, human oesophageal squamous cell carcinoma (SCC) lines.     

miR-146a suppresses the sensitivity to interferon-α in hepatocellular carcinoma cells

Previous studies have demonstrated expression of Toll-like receptors (TLRs) in the surface epithelium of normal ovaries (OSE) and in epithelial ovarian tumors. Most notably, OSE-derived cancers express TLR4, which activates the nuclear factor-kappa B (NF-κB) signaling cascade as a mediator of inflammatory response. Currently, there is considerable interest in elucidating the role of TLR-mediated signaling in cancers. Nevertheless, the expression of TLRs in granulosa cell tumors (GCTs) of the ovary, and the extent to which GCT expression of TLRs may influence cell-signaling pathways and/or modulate the efficacy of chemotherapeutics, has yet to be determined. In the present study, human GCT lines (COV434 and KGN) were utilized to evaluate expression of functional TLR4. TLR4 is expressed in GCT cell lines and ligation of TLR4 with bacterial lipopolysaccharide (LPS) led to IκB degradation and activation of NF-κB. NF-κB activation was confirmed by nuclear localization of NF-κB p65 following treatment with LPS and the naturally occurring ligand, HSP60. Notably, immunoneutralization of TLR4 blocked nuclear localization, and inhibition of NF-κB signaling attenuated LPS-induced TNFα plus increased doubling time in both cell lines. Contradictory to reports using human OSE cell lines, inhibition of NF-κB signaling failed to sensitize GCT lines to TRAIL or cisplatin. In summary, findings herein are the first to demonstrate a functional TLR-signaling pathway specifically in GCTs, and indicate that in contrast to OSE-derived cancers, inhibition of NF-κB does not sensitize GCTs to TRAIL or cisplatin.     

miR-146a suppresses the sensitivity to interferon-α in hepatocellular carcinoma cells

Background

Interferon-based (IFN-based) therapy is effective in the treatment of advanced hepatocellular carcinoma (HCC). However, the issue of resistance to this therapy remains to be solved. The aim of this study was to identify microRNAs (miRNAs) that govern the sensitivity to IFN-α in HCC cells.

Methods

miRNA microarray analysis using IFN-α-resistant clones of PLC/PRF/5 (PLC-Rs) and their parental cells (PLC-P) was conducted. Changes in the anti-cancer effects of IFN-α were studied after gain-of-function and loss-of-function of the candidate miRNA.

Results

miR-146a expression was significantly higher in PLC-Rs than in PLC-P. miR-146a decreased the sensitivity to IFN-α through the suppression of apoptosis. Further experiments showed that miR-146a-related resistance to IFN-α was mediated through SMAD4.

Conclusions

The results indicated that miR-146a regulated the sensitivity of HCC cells to the cytotoxic effects of IFN-α through SMAD4, suggesting that this miRNA could be suitable for prediction of the clinical response and potential therapeutic target in HCC patients on IFN-based therapy.     

Adrenomedullin promotes human endothelial cell proliferation via HIF-1α

Adrenomedullin (ADM) and hypoxia-inducible factor-1α (HIF-1α) are important pro-proliferation genes in response to hypoxic stress. Although it was reported that ADM is a target gene for HIF-1, recent studies also showed that ADM regulates HIF-1 expression and its activity; however, the mechanism of action remains unknown. Two stable human endothelial cell lines with HIF-1α knockdown by hy926-siHIF-1α or HMEC-siHIF-1α were established. mRNA and protein expression of ADM and HIF-1α in EA.hy926 and HMEC1 cells were examined under hypoxic stress. Upon ADM treatment, cell proliferation was investigated and the expression profiles of HIF-1α and its target genes (VEGF, PFKP, PGK1, and AK1) were examined. Furthermore, the proline hydroxylase (PHD) mRNA level and its activity were investigated. We observed that mRNA and protein expression of ADM in hypoxia are earlier events than HIF-1α in EA.hy926 and HMEC1 cells. ADM-promoted cell proliferation of endothelial cells, which was HIF-1α dependent. We also found that ADM up-regulated the mRNA and protein expressions of HIF-1α- and HIF-1-targeted genes, and ADM up-regulated the protein expressions of HIF-1α through down-regulation of PHD mRNA expression and PHD activity.     

Silencing TRIP13 inhibits cell growth and metastasis of hepatocellular carcinoma by activating of TGF-β1/smad3

Background

TRIP13 is highly expressed in several cancers and is closely connected with cancer progression. However, its roles on the growth and metastasis of hepatocellular carcinoma (HCC), and the underlying mechanism are still unclear.

Methods

Combining bioinformatics with previous studies, the correlation between TRIP13 and HCC was predicted. TRIP13 expressions from 52 HCC patients and several cell lines were determined. The effects of silencing TRIP13 on cell viability, apoptosis, migration and invasion were respectively detected using CCK-8, flow cytometry and Transwell. qRT-PCR and western blot were performed to reveal associated mechanism. A HCC model was established in BALB/c-nu mice by transplanting HepG2 cells. TRIP13 protein expression and apoptosis in mice tissues were accordingly detected by Immunohistochemistry and TUNEL.

Results

High expression of TRIP13 in HCC affected the survival rate and it was enriched in RNA degradation and fatty acid metabolism according to bioinformatics and prediction from previous literature. Increased expression of TRIP13 in HCC patient tissues was associated with the progression of HCC. Silencing TRIP13 inhibited cell viability, migration and invasion, and induced cell apoptosis. TRIP13 knockdown also suppressed the formation of tumor in vivo. Meanwhile, silencing TRIP13 decreased the expressions of Ki67 and MMP-2 and increased the expressions of TIMP-2, active-caspase-3 and TGF-β1/smad3 signaling- related genes.

Conclusions

Silencing TRIP13 acts as a tumor suppresser of HCC to repress cell growth and metastasis in vitro and in vivo, and such a phenomenon possibly involved activation of TGF-β1/smad3 signaling.