Tg737 signaling is required for hypoxia-enhanced invasion and migration of hepatoma cells

W436, a novel SMART derivative, exhibits anti-hepatocarcinoma activity by inducing apoptosis and G2/M cell cycle arrest in vitro and in vivo and induces protective autophagy

Hepatocellular carcinoma (HCC) is considered one of the most common primary liver cancers and the second leading cause of cancer-associated mortality around the world annually. Therefore, it is urgent to develop novel drugs for HCC therapy. We synthesized a novel 4-substituted-methoxybenzoyl-aryl-thiazole (SMART) analog, (5-(4-aminopiperidin-1-yl)-2-phenyl-2H-1,2,3-triazol-4-yl) (3,4,5-trimethoxyphenyl) methanone (W436), with higher solubility, stability, and antitumor activity than SMART against HCC cells in vivo. The purpose of this study was to investigate the mechanisms by which W436 inhibited cell growth in HCC cells. We observed that W436 inhibited the proliferation of HepG2 and Hep3B cells in a dose-dependent manner. Importantly, the anticancer activity of W436 against HCC cells was even higher than that of SMART in vivo. In addition, the antiproliferative effects of W436 on HCC cells were associated with G2/M cell cycle arrest and apoptosis via the activation of reactive oxygen species-mediated mitochondrial apoptotic pathway. W436 also induced protective autophagy by inhibiting the protein kinase B/mammalian target of rapamycin pathway. At the same time, W436 treatment inhibited the cell adhesion and invasion as well as the process of epithelial-to-mesenchymal transition Taken together, our results showed that W436 had the promising potential for the therapeutic treatment of HCC with improved solubility, stability, and bioavailability.

Carbon black nanoparticles induce HDAC6-mediated inflammatory responses in 16HBE cells

Long-term inhalation of carbon black nanoparticles (CBNPs) leads to pulmonary inflammatory diseases. Histone deacetylase 6 (HDAC6) has been identified as an important regulator in the development of inflammatory disorders. However, the direct involvement of HDAC6 in CBNPs-induced pulmonary inflammatory responses remains unclear. To explore whether HDAC6 participates in CBNPs-induced pulmonary inflammation, human bronchial epithelial cell line (16HBE cells) was transfected with HDAC6 small interference RNA (siRNA) and then exposed to CBNPs at concentrations of 0, 25, and 50 µg/ml for 24 h. Intracellular HDAC6 and intraflagellar transport protein 88 (IFT88) mRNA and protein were determined by real-time polymerase chain reaction and Western blot, respectively. The secretions of inflammatory cytokines including interleukin (IL)-8, tumor necrosis factor (TNF)-α, IL-6, and IL-1β were measured by enzyme-linked immunosorbent assay. CBNPs induced a significant increase in the expressions of IL-8 and IL-6, accompanied by a high level of intracellular HDAC6 mRNA when compared with a blank control group (p < 0.05). However, there were no significant changes in the levels of TNF-α secretion, intracellular HDAC6 and IFT88 protein induced by CBNPs (p > 0.05). The HDAC6 mRNA expression was significantly suppressed in HDAC6 siRNA-transfected cells (p < 0.05). The secretions of IL-8, TNF-α, and IL-6 were significantly less in HDAC6 siRNA-transfected cells than that in normal 16HBE cells with exposure to 25 or 50 µg/ml of CBNPs, but intracellular IFT88 mRNA expression was markedly increased in HDAC6 siRNA-transfected cells when compared with normal 16HBE cells exposed to 50 µg/ml of CBNPs (all p < 0.05). Downregulation of the HDAC6 gene inhibits CBNPs-induced inflammatory responses in bronchial epithelial cells, partially through regulating IFT88 expression. It is suggested that CBNPs may trigger inflammatory responses in bronchial epithelial cells by an HDAC6/IFT88-dependent pathway.

Crosstalk between Stress Granules, Exosomes, Tumour Antigens, and Immune Cells: Significance for Cancer Immunity

RNA granules and exosomes produced by tumour cells under various stresses in the microenvironment act as critical determinants of cell survival by promoting angiogenesis, cancer metastasis, chemoresistance, and immunosuppression. Meanwhile, developmental cancer/testis (CT) antigens that are normally sequestered in male germ cells of the testes, but which are overexpressed in malignant tumour cells, can function as tumour antigens triggering immune responses. As CT antigens are potential vaccine candidates for use in cancer immunotherapy, they could be targeted together with crosstalk between stress granules, exosomes, and immune cells for a synergistic effect. In this review, we describe the effects of exosomes and exosomal components presented to the recipient cells under different types of stresses on immune cells and cancer progression. Furthermore, we discuss their significance for cancer immunity, as well as the outlook for their future application.

Primary Cilia Blockage Promotes the Malignant Behaviors of Hepatocellular Carcinoma via Induction of Autophagy

Primary cilia are organelles protruding from cell surface into environment that function in regulating cell cycle and modulating cilia-related signal. Primary ciliogenesis and autophagy play important roles in tumorigenesis. However, the functions and interactions between primary cilia and autophagy in hepatocellular carcinoma (HCC) have not been reported yet. Here, we aimed to investigate the relationship and function of primary cilia and autophagy in HCC. In vitro, we showed that serum starvation stimuli could trigger primary ciliogenesis in HCC cells. Blockage of primary ciliogenesis by IFT88 silencing enhanced the proliferation, migration, and invasion ability of HCC cells. In addition, inhibition of primary cilia could positively regulate autophagy. However, the proliferation, migration, and invasion ability which were promoted by IFT88 silencing could be partly reversed by inhibition of autophagy. In vivo, interference of primary cilia led to acceleration of tumor growth and increase of autophagic flux in xenograft HCC mouse models. Moreover, IFT88 high expression or ATG7 low expression in HCC tissues was correlated with longer survival time indicated by the Cancer Genome Atlas (TCGA) analysis. In conclusion, our study demonstrated that blockage of primary ciliogenesis by IFT88 silencing had protumor effects through induction of autophagy in HCC. These findings define a newly recognized role of primary cilia and autophagy in HCC.

The ATP-binding cassette transporter ABCF1 is a hepatic oncofetal protein that promotes chemoresistance, EMT and cancer stemness in hepatocellular carcinoma

ATP-binding cassette (ABC) transporters mediate multidrug resistance and cancer stem cell properties in various model systems. Yet, their biological significance in cancers, especially in hepatocellular carcinoma (HCC), remains unclear. In this study, we investigated the function of ABCF1 in HCC and explored its potential as a therapeutic target. ABCF1 was highly expressed in fetal mouse livers but not in normal adult livers. ABCF1 expression was upregulated in HCCs. These results demonstrate that ABCF1 functions as a hepatic oncofetal protein. We further demonstrated elevated ABCF1 expression in HCC cells upon acquiring chemoresistance. Suppression of ABCF1 by siRNA sensitized both parental cells and chemoresistant cells to chemotherapeutic agents. Reversely, ABCF1 overexpression promoted chemoresistance and drug efflux. In addition, overexpression of ABCF1 enhanced migration, spheroid and colony formation and epithelial-mesenchymal transition (EMT) induction. RNA sequencing analysis revealed EMT inducers HIF1α/IL8 and Sox4 as potential mediators for the oncogenic effect of ABCF1 in HCC progression. Together, this study illustrates that ABCF1 is a novel potential therapeutic target for HCC treatment.

Primary cilia proteins: ciliary and extraciliary sites and functions

Primary cilia are immotile organelles known for their roles in development and cell signaling. Defects in primary cilia result in a range of disorders named ciliopathies. Because this organelle can be found singularly on almost all cell types, its importance extends to most organ systems. As such, elucidating the importance of the primary cilium has attracted researchers from all biological disciplines. As the primary cilia field expands, caution is warranted in attributing biological defects solely to the function of this organelle, since many of these "ciliary" proteins are found at other sites in cells and likely have non-ciliary functions. Indeed, many, if not all, cilia proteins have locations and functions outside the primary cilium. Extraciliary functions are known to include cell cycle regulation, cytoskeletal regulation, and trafficking. Cilia proteins have been observed in the nucleus, at the Golgi apparatus, and even in immune synapses of T cells (interestingly, a non-ciliated cell). Given the abundance of extraciliary sites and functions, it can be difficult to definitively attribute an observed phenotype solely to defective cilia rather than to some defective extraciliary function or a combination of both. Thus, extraciliary sites and functions of cilia proteins need to be considered, as well as experimentally determined. Through such consideration, we will understand the true role of the primary cilium in disease as compared to other cellular processes' influences in mediating disease (or through a combination of both). Here, we review a compilation of known extraciliary sites and functions of "cilia" proteins as a means to demonstrate the potential non-ciliary roles for these proteins.

Hypoxia inducible factors in hepatocellular carcinoma

Hepatocellular carcinoma is one of the most prevalent and lethal cancers with limited therapeutic options. Pathogenesis of this disease involves tumor hypoxia and the activation of hypoxia inducible factors. In this review, we describe the current understanding of hypoxia signaling pathway and summarize the expression, function and target genes of hypoxia inducible factors in hepatocellular carcinoma. We also highlight the recent progress in hypoxia-targeted therapeutic strategies in hepatocellular carcinoma and discuss further the future efforts for the study of hypoxia and/or hypoxia inducible factors in this deadly disease.

Tg737 acts as a key driver of invasion and migration in liver cancer stem cells and correlates with poor prognosis in patients with hepatocellular carcinoma

We previously demonstrated that the Tg737 gene plays a critical role in the carcinogenesis of hepatocellular carcinoma (HCC). However, few systematic investigations have focused on the biological function of Tg737 in the invasion and migration of liver cancer stem cells (LCSCs) and on its clinical significance. In this study, Tg737 overexpression was achieved via gene transfection in MHCC97-H side population (SP) cells, which are considered a model for LCSCs in scientific studies. Tg737 overexpression significantly inhibited the invasion and migration of SP cells in an extracellular signal-regulated kinase1/2 (ERK1/2)/matrix metalloproteinase-2 (MMP-2)-dependent manner. Furthermore, Tg737 expression was frequently decreased in HCC tissues relative to that in adjacent noncancerous liver tissues. This decreased expression was significantly associated with tumor differentiation, the American Joint Committee on Cancer (AJCC) stage, metastasis, tumor size, vascular invasion, alpha-fetoprotein (AFP) levels, and tumor number. Moreover, multivariate Cox regression analyses demonstrated that Tg737 expression was an independent factor for predicting the overall survival of HCC patients. Notably, Kaplan-Meier analysis further showed that overall survival was significantly worse among patients with low Tg737 expression. Collectively, our findings demonstrated that Tg737 is a poor prognostic marker in patients with HCC, which may be due to its ability to promote LCSCs invasion and migration. These results provide a basis for investigating of Tg737 as a novel prognostic biomarker and therapeutic target.

Tg737 regulates epithelial-mesenchymal transition and cancer stem cell properties via a negative feedback circuit between Snail and HNF4α during liver stem cell malignant transformation

Determining the origin of liver cancer stem cells is important for treating hepatocellular carcinoma. Tg737 deficiency plays an important role in the malignant transformation of liver stem cells, but the underlying mechanism remains unclear. Here we established a chemical-induced mouse hepatoma model and found that Tg737 and hepatocyte nuclear factor 4-alpha (HNF4α) expression decreased and epithelial-mesenchymal transition (EMT)-related marker expression increased during liver cancer development. To investigate the underlying mechanism, we knocked down Tg737 in WB-F344 (WB) rat hepatic oval cells. Loss of Tg737 resulted in nuclear β-catenin accumulation and activation of the Wnt/β-catenin pathway, which further promoted EMT and the malignant phenotype. XAV939, a β-catenin inhibitor, attenuated WB cell malignant transformation due to Tg737 knockdown. To clarify the relationships of Tg737, the β-catenin pathway, and HNF4α, we inhibited Snail and overexpressed HNF4α after Tg737 knockdown in WB cells and found that Snail and HNF4α comprise a negative feedback circuit. Taken together, the results showed that Tg737 regulates a Wnt/β-catenin/Snail-HNF4α negative feedback circuit, thereby blocking EMT and the malignant transformation of liver stem cells to liver cancer stem cells.

MicroRNA-548a-5p promotes proliferation and inhibits apoptosis in hepatocellular carcinoma cells by targeting Tg737

AIM: To investigate whether Tg737 is regulated by microRNA-548a-5p (miR-548a-5p), and correlates with hepatocellular carcinoma (HCC) cell proliferation and apoptosis.

METHODS: Assays of loss of function of Tg737 were performed by the colony formation assay, CCK assay and cell cycle assay in HCC cell lines. The interaction between miR-548a-5p and its downstream target, Tg737, was evaluated by a dual-luciferase reporter assay and quantitative real-time polymerase chain reaction. Tg737 was then up-regulated in HCC cells to evaluate its effect on miR-548a-5p regulation. HepG2 cells stably overexpressing miR-548a-5p or miR-control were also subcutaneously inoculated into nude mice to evaluate the effect of miR-548a-5p up-regulation on in vivo tumor growth. As the final step, the effect of miR-548a-5p on the apoptosis induced by cisplatin was evaluated by flow cytometry.

RESULTS: Down-regulation of Tg737, which is a target gene of miR-548a-5p, accelerated HCC cell proliferation, and miR-548a-5p promoted HCC cell proliferation in vitro and in vivo. Like the down-regulation of Tg737, overexpression of miR-548a-5p in HCC cell lines promoted cell proliferation, increased colony forming ability and hampered cell apoptosis. In addition, miR-548a-5p overexpression increased HCC cell growth in vivo. MiR-548a-5p down-regulated Tg737 expression through direct contact with its 3’ untranslated region (UTR), and miR-548a-5p expression was negatively correlated with Tg737 levels in HCC specimens. Restoring Tg737 (without the 3’UTR) significantly hampered miR-548a-5p induced cell proliferation, and rescued the miR-548a-5p induced cell proliferation inhibition and apoptosis induced by cisplatin.

CONCLUSION: MiR-548a-5p negatively regulates the tumor inhibitor gene Tg737 and promotes tumorigenesis in vitro and in vivo, indicating its potential as a novel therapeutic target for HCC.

The hallmarks of cancer: relevance to the pathogenesis of polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive inherited disorder in which renal tissue is gradually replaced with fluid-filled cysts, giving rise to chronic kidney disease (CKD) and progressive loss of renal function. ADPKD is also associated with liver ductal cysts, hypertension, chronic pain and extra-renal problems such as cerebral aneurysms. Intriguingly, improved understanding of the signalling and pathological derangements characteristic of ADPKD has revealed marked similarities to those of solid tumours, even though the gross presentation of tumours and the greater morbidity and mortality associated with tumour invasion and metastasis would initially suggest entirely different disease processes. The commonalities between ADPKD and cancer are provocative, particularly in the context of recent preclinical and clinical studies of ADPKD that have shown promise with drugs that were originally developed for cancer. The potential therapeutic benefit of such repurposing has led us to review in detail the pathological features of ADPKD through the lens of the defined, classic hallmarks of cancer. In addition, we have evaluated features typical of ADPKD, and determined whether evidence supports the presence of such features in cancer cells. This analysis, which places pathological processes in the context of defined signalling pathways and approved signalling inhibitors, highlights potential avenues for further research and therapeutic exploitation in both diseases.

Transarterial chemoembolization (TACE) plus percutaneous ethanol injection (PEI) for the treatment of unresectable hepatocellular carcinoma: a meta-analysis of randomized controlled trials

Transarterial chemoembolization (TACE) plus percutaneous ethanol injection (PEI) have been used for patients with unresectable hepatocellular carcinoma (HCC). However, whether the combination therapy of TACE plus PEI is better than TACE or PEI alone in the treatment of HCC remains controversial. Thus, we conducted this meta-analysis to assess the efficacy of combined therapy for unresectable HCC compared with that of TACE or PEI alone. Randomized controlled trials (RCTs) published from Pubmed, Embase, Web Of Science, Chinese Biomedical Literature database (SinoMed), China National Knowledge Infrastructure (CNKI), and Wanfang database, were systematically reviewed to assess the survival benefits and tumor recurrence for HCC patients treated with TACE plus PEI. Pooled risk ratio (RR) with 95% confidence intervals (95% CIs) for survival rate and tumor recurrence rate were calculated using a random-effects or fixed-effects model, depending on the heterogeneity between the included studies. 19 RCTs met the inclusion criteria were included in this meta-analysis with a total number of 1948 patients. The pooled results showed that the combination therapy of TACE plus PEI significantly improved 1, 2, 3-year survival rate [RR1-year = 1.24, 95% CI: 1.17-1.31, P = 0.000; RR2-year = 1.64, 95% CI: 1.44-1.87, P = 0.000; RR3-year = 2.27, 95% CI: 1.93-2.67, P = 0.000] compared with that of TACE or PEI alone. The local tumor recurrence rate in HCC patients treated with TACE plus PEI was lower than that of monotherapy (RR = 0.53, 95% CI: 0.29-0.96; P = 0.035). The combined therapy of TACE with PEI also significantly reduced the AFP level (RR = 1.40, 95% CI: 1.19-1.66, P = 0.000) and tumor size (>50%) (RR = 1.61, 95% CI: 1.40-1.85, P = 0.000). This meta-analysis confirms the benefits of TACE + PEI in the treatment of unresectable HCC, with an improvement in survival rate, and a reduction in local tumor recurrence, AFP level, and tumor size.

Comparative effectiveness of radiofrequency ablation with or without transarterial chemoembolization for hepatocellular carcinoma

The aim of this study is to compare the overall survival in patients with hepatocellular carcinoma (HCC) treated with radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) versus RFA alone. All eligible studies were collected from the PubMed, the Cochrane Library, and the Embase electronic databases. The outcomes were overall survival rates. We used odds ratios to assess the strength of the association, and 95% confidence intervals give a sense of the precision of the estimate. Statistical analyses were performed by Review Manager 5.0 and Stata 11.0. A total of 19 available studies were considered in the present meta-analysis. When all groups were pooled, meta-analysis showed that RFA plus TACE significantly improved the survival rates of patients with HCC at 1, 3, and 5 years compared with RFA alone. The combination of RFA with TACE has advantages in improving overall survival rate, and provides better prognosis for HCC patients.