Resistance Of Hepatocellular Carcinoma Cells Research Articles

ETS-1 induces Sorafenib-resistance in hepatocellular carcinoma cells via regulating transcription factor activity of PXR.

Transcription factor E26 transformation specific sequence 1 (ETS-1) is a primary regulator in the metastasis of human cancer cells, especially hepatocellular carcinoma (HCC) cells; and it would affect the prognosis of HCC patients who received chemotherapies. However, the regulatory role of ETS-1 in the resistance of HCC cells to molecular-targeting agent remains poorly understood. In the present work, we demonstrate that high ETS-1 expression correlates with poor prognosis of advanced HCC patients received Sorafenib treatment. Mechanistically, ETS-1 binds to nuclear Pregnane X receptor (PXR) directly and enhances PXR's transcription factor activity, which further leads to the induction of the PXR's downstream multi-drug resistance related genes. Overexpression of ETS-1 accelerates the metabolic clearance of Sorafenib in HCC cells and leads to the better survival and faster migration of those cells. The therapeutic studies show that ETS-1 promotes the Sorafenib-resistance of HCC tumor models and ETS-1 blockade enhances the anti-tumor capacity of Sorafenib by decreasing PXR activation. Thus, our study suggests that ETS-1 could enhance the activation of PXR and be a potential therapeutic target for overcoming Sorafenib resistance in HCC treatment.

Inhibition of cFLIP overcomes acquired resistance to sorafenib via reducing ER stress‑related autophagy in hepatocellular carcinoma.

Treatment with sorafenib remains the first‑line therapy for patients with advanced stage hepatocellular carcinoma (HCC), however, it has limited effect due to the acquired resistance of HCC. Elucidating the potential mechanism can assist in developing promising strategies to overcome this resistance. In the present study, a sorafenib‑refractory HCC cell was established from the Huh7 parental cell line, which was resistant to sorafenib mediated‑cytotoxicity invitro. The cell inhibition rate and apoptosis of cells were determined by MTT assay and flow cytometry, respectively. Electronic microscopy was used to detect autophagy in cells. The expression levels of endoplasmic reticulum stress (ERS)‑related protein, apoptosis‑related protein and cFLIP were examined by western blot analysis. Co‑immunoprecipitation was used to examine the ubiquitination of cFLIP. It was found that sustained exposure to sorafenib activated ERS in the HCC cells. The ERS inhibitor partly increased sorafenib‑induced cell death in these cells. In addition, ERS‑induced autophagy was important in resistance to sorafenib, as inhibiting autophagy led to the resistant HCC cells becoming more sensitive to sorafenib. However, ERS‑induced apoptosis did not differ between sorafenib‑sensitive HCC cells and sorafenib‑refractory HCC cells. The knockdown of cFLIP reversed the acquired sorafenib resistance by activating caspase‑8 and inhibiting activated ERS in the sorafenib‑resistant HCC cells. Mechanistically, a sustained increased in cFLIP was found to be dependent on USP2‑induced deubiquitination. In conclusion, cFLIP was identified as a potential target for overcoming the acquired sorafenib resistance in HCC. These effects occurred partially through reducing ERS‑related autophagy in HCC.

NRAL mediates cisplatin resistance in hepatocellular carcinoma via miR-340-5p/Nrf2 axis.

Recent studies have shown that long non-coding RNAs (lncRNAs) play a pivotal role in the pathogenesis and progression of hepatocellular carcinoma (HCC). However, the biological action and potential mechanism of liver cancer cell drug resistance have not been clearly clarified. In this study, lncRNAs were screened and differentially expressed in parental and cisplatin-resistant cell lines (HepG2 and HepG2/CDDP). A novel lncRNA, termed NRAL (Nrf2 regulation-associated lncRNA), was identified, and the initial results indicated that it was highly expressed in HepG2 cisplatin resistant cell lines compared to their parental counterparts. Functionally, NRAL depletion significantly enhanced CDDP-mediated cytotoxicity and apoptosis in two cisplatin-resistant HCC cell lines. Mechanistically, the results indicated that NRAL regulates Nrf2 expression through miR-340-5p serving as a competing endogenous RNA (ceRNA), thus influencing the CDDP-induced phenotype in HCC. Collectively, the present investigation suggest that the NRAL/miR-340-5p/Nrf2 axis mediates cisplatin resistance in HCC, which may provide novel targets for overcoming cisplatin resistance in hepatocellular carcinoma cells.

PO-433 The modulation of redox homeostasis and induction of ferroptotic cell death in hepatocellular carcinoma as an anticancer strategy

IntroductionFerroptosis has recently been identified as a form of programmed cell death caused by an accumulation of lipid reactive oxygen species (ROS). However, little is yet known about the role in hepatocellular carcinoma (HCC) and its signalling mechanism as well the modulation of ROS.Material and methodsHuman HCC cell lines were treated with different concentrations of ROS modulators (Auranofin, Erastin, BSO). Cell death was determined by analysis of PI-stained nuclei using flow cytometry. ROS production and lipid peroxidation were analysed at early time points before cell death starts. For mechanistic studies we performed Western Blot and a Proteome array. Different inhibitors of cell death target proteins, ROS-scavengers as well as lipoxygenase inhibitors were used. To investigate the functional relevance of NAPDH oxidases (NOX) 1 and 4 for ROS modulation and ferroptosis we genetically silenced its genes using three distinct siRNAs and we used the NOX1/4-inhibitor GKT137831.Results and discussionsCompared to the single treatment, Auranofin/BSO-cotreatment as well as Erastin/BSO-cotreatment acted in concert to trigger cell death and to reduce cell viability of HCC cells in a dose- and time-dependent manner. Furthermore, both cotreatments induce ROS production, lipid peroxidation and ferroptotic cell death, which could be inhibited by the use of Ferrostatin-1 (inhibitor of lipid peroxidation) and Liproxstatin-1 (specific inhibitor of ferroptosis). The broad-range caspase inhibitor zVAD.fmk failed to rescue cells from Auranofin/BSO- or Erastin/BSO-cotreatment induced cell death. No activation of caspases-3 could be seen in the proteome profiler apoptosis assay. Importantly, the selective lipoxygenase (LOX) inhibitor Baicalain and the pan-LOX inhibitor NDGA protect HCC cells from Auranofin/BSO- and Erastin/BSO-cotreatment stimulated lipid peroxidation, ROS generation and cell death, indication that the induction of ferroptosis may bypass apoptosis resistance of HCC cells. Mechanistic studies showed that Auranofin/BSO-cotreatment decreased TrxR-activity, led to Nrf2 accumulation and promoted the activation of HO-1. In contrast, NOX 1 and 4 were involved in Erastin/BSO-mediated cell death and the use of the NOX1/4-inhibitor GKT137831 rescued HCC cells from the Erastin/BSO-induced cell death.ConclusionBy providing new insights into the molecular regulation of ROS and ferroptosis, our study contributes to the development of novel treatment strategies to reactivate programmed cell death in HCC cells.

Abstract 896: Adjutant therapeutic strategy for sorafenib-resistant hepatocellular carcinoma

Abstract Purpose: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the leading cause of cancer mortality worldwide. To date, Sorafenib remains the standard of care for advanced HCCs not amenable to curative therapies such as surgery or local ablation. Unfortunately, clinical efficacy of Sorafenib remains marginal as most HCC patients receiving Sorafenib treatment develop Sorafenib resistance. The recently approved regorafenib is the only rescue therapy for patients who fail Sorafenib treatment. However, the effect of regorafenib is also far from satisfactory. Therefore, new strategies to overcome sorefenib resistance are critically warranted. Recently, one FDA-approved drug, here we tentatively named as “FA”, was shown to suppress different cancer malignancy by various mechanisms including inhibiting the development of drug resistance in cancer. These findings provide a rationale for combination treatment of this FA drug with Sorafenib in Sorafenib-resistant HCC. Results: Two Sorafenib-resistant HCC cell lines of Hep3B and HepG2215 were established. The Sorafenib resistance characteristics of the HCC cells were further verified by western blotting assay detecting protein tyrosine phosphorylation. We also demonstarted the resistant HCC cells expressed stemness-related genes and showed high ability of cell migration and metastasis. Combination use of FA drug and Sorafenib significantly suppressed the cell viability as well as the stemness-related properties of Sorafenib-resistant HCC cells, including stemness-related gene/protein expression, secondary sphere formation, and the cell migration. Conclusion: Combination use of FA drug and Sorafenib would be a potential therapeutic strategy for Sorafenib-resistant HCC treatment. Citation Format: Syue-Wei Peng, Yi-Heng Lin, Ming-Hao Teng, Hung-Cheng Lai, Te-Sheng Chang, Yen-Hua Huang. Adjutant therapeutic strategy for sorafenib-resistant hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 896.

Sodium orthovanadate overcomes sorafenib resistance of hepatocellular carcinoma cells by inhibiting Na+/K+-ATPase activity and hypoxia-inducible pathways

The resistance to sorafenib highly affects its clinical benefits for treating hepatocellular carcinoma (HCC). Sodium orthovanadate (SOV) is a phosphate analog that displays anti-cancer activities against various types of malignancies including HCC. The present study has demonstrated that SOV is able to overcome sorafenib resistance and strengthens sorafenib in suppressing sorafenib-resistant HCC cells in vitro and in animal models. Similar to its action on parental HCC cells, SOV induced cell cycle arrest at G2/M phases by regulating cyclin B1 and cyclin-dependent kinase 1, and apoptosis by reducing mitochondrial membrane potential, in sorafenib-resistant HCC cells. More importantly, SOV inhibited ATPase activity, which was significantly elevated in sorafenib-resistant HCC cells. SOV also reduced the expression of HIF-1α and HIF-2α and their nuclear translocation, resulting in downregulation of their downstream factors including vascular endothelial growth factor, lactate dehydrogenase-A and glucose transporter 1. Its ability to inhibit ATPase activity and hypoxia-inducible pathways enabled SOV to efficiently suppress both normoxic and hypoxic cells, which compose cancer cell populations inside sorafenib-resistant HCC tumors. The present results indicate that SOV may be a potent candidate drug for overcoming the resistance to sorafenib in treating HCC.

Integrated multi-omics data analysis identifying novel drug sensitivity-associated molecular targets of hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and the third-leading cause of malignancy-associated mortality worldwide. HCC cells are highly resistant to chemotherapeutic agents. Therefore, there are currently only two US Food and Drug Administration-approved drugs available for the treatment of HCC. The objective of the present study was to analyze the results of previously published high-throughput drug screening, and in vitro genomic and transcriptomic data from HCC cell lines, and to integrate the obtained results to define the underlying molecular mechanisms of drug sensitivity and resistance in HCC cells. The results of treatment with 225 different small molecules on 14 different HCC cell lines were retrieved from the Genomics of Drug Sensitivity in Cancer database and analyzed. Cluster analysis using the treatment results determined that HCC cell lines consist of two groups, according to their drug response profiles. Continued analyses of these two groups with Gene Set Enrichment Analysis method revealed 6 treatment-sensitive molecular targets (epidermal growth factor receptor, mechanistic target of rapamycin, deoxyribonucleic acid-dependent protein kinase, the Aurora kinases, Bruton's tyrosine kinase and phosphoinositide 3-kinase; all P<0.05) and partially effective drugs. Genetic and genome-wide gene expression data analyses of the determined targets and their known biological partners revealed 2 somatically mutated and 13 differentially expressed genes, which differed between drug-resistant and drug-sensitive HCC cells. Integration of the obtained data into a short molecular pathway revealed a drug treatment-sensitive signaling axis in HCC cells. In conclusion, the results of the present study provide novel drug sensitivity-associated molecular targets for the development of novel personalized and targeted molecular therapies against HCC.

Downregulation of YAP inhibits proliferation, invasion and increases cisplatin sensitivity in human hepatocellular carcinoma cells.

Yes-associated protein (YAP) serves an essential role in tumorigenesis. However, the potential role and the molecular mechanism underlying the effect of YAP on hepatocellular carcinoma (HCC) cells have not been elucidated. In the current study, it was revealed that YAP expression was increased significantly in HCC cancer tissues and its overexpression was associated with tumor differentiation. The silencing of YAP by small interferring RNA led to the inhibition of HCC cell growth, which was associated with the promotion of apoptosis. The silencing of YAP also decreased the invasive potential of HCC cells and the activity of the phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT) signaling pathway. Furthermore, silencing of YAP increased the chemosensitivity of HCC cells to cisplatin (CDDP) through inactivation of the PI3K/AKT signaling pathway. In vivo studies using PDTX model suggested a promotive role for YAP in the growth of HCC and knockdown of YAP increased the anti-tumor activity of CDDP. Taken together, these results revealed that YAP is overexpressed in HCC, and promotes proliferation, invasion and drug resistance of HCC cells. Inhibition of YAP, alone or in combination with traditional chemotherapy, may effectively combat HCC.

Triclosan treatment decreased the antitumor effect of sorafenib on hepatocellular carcinoma cells.

BackgroundTriclosan is a widely applied antimicrobial agent which affects the endocrine system and homeostasis; it may also promote the cirrhosis and hepatocellular carcinoma (HCC) growth in a mice model. The exact roles of triclosan in regulating human hepatocellular carcinoma development and treatment remain unknown.MethodsMHCC97-H, a highly aggressive HCC cell line, was treated with indicated concentration of triclosan or sorafenib. The expression of drug-resistance genes was examined by qPCR. The clearance or metabolism of sorafenib was determined by liquid chromatograph-mass spectrometer/mass spectrometer (LC-MS/MS). MTT assay was used to examine the MHCC97-H cell proliferation. Nude mice were used to exam the anti-tumor effect of sorafenib on subcutaneous and intrahepatic growth of MHCC97-H cells.ResultsIn the present study, triclosan could induce the expression of drug-resistance genes in MHCC97-H cells (a highly aggressive HCC cell line), accelerate the clearance of sorafenib, and attenuate the anti-proliferation effect of this molecular targeted agent in MHCC97-H cells. Triclosan decreased the antitumor effect of sorafenib on subcutaneous and intrahepatic growth of MHCC97-H in nude mice.ConclusionBy discovering the fact that triclosan treatment enhances sorafenib resistance in HCC cells, this work suggests exposure of triclosan is detrimental to HCC patients during chemotherapy.

MicroRNA-125b reverses oxaliplatin resistance in hepatocellular carcinoma by negatively regulating EVA1A mediated autophagy

EVA1A (also known as transmembrane protein 166) is a transmembrane protein involved in the regulation of autophagy that acts as an adaptor protein to recruit or bind proteins in the lysosome or endoplasmic reticulum. In the present study, we identified EVA1A as a target of microRNA-125b (miR-125b), a member of a highly conserved family of miRNAs that has been proposed as a biomarker for hepatocellular carcinoma (HCC). Analysis of oxaliplatin-sensitive and oxaliplatin-resistant HCC cell lines showed that miR-125b is downregulated in resistant cells and its overexpression in sensitive cells decreased resistance to oxaliplatin by inhibiting cell proliferation, migration and epithelial–mesenchymal transition (EMT). EVA1A expression was shown to be upregulated in tissue samples from oxaliplatin-resistant HCC patients, and its ectopic expression partially induced autophagy and reversed the effect of miR-125b on inhibiting the growth of oxaliplatin-resistant cell lines and xenograft tumors. Taken together, our results suggest that miR-125b plays a role in the resistance of HCC cells to chemotherapy via a mechanism involving the downregulation of EVA1A-mediated autophagy.

Sphingosine kinase 1 overexpression is associated with poor prognosis and oxaliplatin resistance in hepatocellular carcinoma.

Sphingosine kinase 1 (SphK1) is a tumor-associated protein overexpressed in numerous types of cancer and is involved in the regulation of resistance to multiple chemotherapeutic agents. However, the role of SphK1 in the resistance of hepatocellular carcinoma (HCC) to oxaliplatin remains unclear. In the present study, the transcriptional levels of SphK1 were analyzed in 21 patients with HCC and the SphK1 expression levels were identified to be significantly upregulated in HCC tissue compared with that in adjacent normal tissue samples (P<0.001). High SphK1 expression correlated with shorter overall survival times in patients with HCC (P<0.05). Furthermore, SphK1 expression levels and activity were analyzed in a series of HCC cell lines and they were both demonstrated to be associated with resistance to oxaliplatin. Conversely, the knockdown of SphK1 protein expression resulted in decreased oxaliplatin resistance in SK-Hep1 and HCCLM3 cell lines. In addition, the results of the current study demonstrated that the downregulation of SphK1 decreased the levels of phosphorylated AKT serine/threonine kinase (Akt) and glycogen synthase kinase-3β (GSK3β), suggesting that SphK1 promotes oxaliplatin resistance of HCC cells via modulation of the Akt/GSK3β signaling pathway. To the best of our knowledge, the present study is the first to report that SphK1 is associated with poor prognosis and oxaliplatin resistance in HCC. Thus, the findings of the current study have provided a direction for the identification of novel therapeutic targets for the treatment of HCC.

FSCN‑1 increases doxorubicin resistance in hepatocellular carcinoma through promotion of epithelial-mesenchymal transition.

Resistance to chemotherapy drugs remains a significant problem for the treatment of many types of cancer. Fascin-1 (FSCN-1) is an actin-bundling protein involved in the invasion and metastasis of a variety of tumors. However, its involvement in drug resistance in hepatocellular carcinoma (HCC) remains unclear. The present study aimed to investigate the function of FSCN-1 in HCC resistance to doxorubicin (DOX). FSCN-1 expression was increased in DOX-resistant HCC cell lines (SNU449 and SNU387) compared with DOX-sensitive cell lines (Huh7 and Hep3B). The resistance of HCC cells to DOX was decreased following FSCN-1 knockdown with small interfering RNA. FSCN-1 knockdown also significantly altered the expression of key markers of epithelial-mesenchymal transition (EMT). Notably, vimentin expression was reduced and epithelial-cadherin expression was increased. Furthermore, when EMT was suppressed through knockdown of Twist, an essential pathway of DOX-induced EMT, the viability of HCC cells following treatment with DOX was not affected by FSCN-1 expression. Furthermore, FSCN-1 knockdown eliminated hypoxia-induced doxorubicin resistance and EMT. The results of the present study indicated that FSCN-1 expression increased DOX resistance in HCC cells via the promotion of EMT, and this phenomenon was maintained in a hypoxic environment. FSCN-1 potentially represents a novel target to overcome resistance to DOX in HCC.

Heme oxygenase-1/carbon monoxide axis suppresses transforming growth factor-β1-induced growth inhibition by increasing ERK1/2-mediated phosphorylation of Smad3 at Thr-179 in human hepatocellular carcinoma cell lines

Heme oxygenase-1 (HO-1) has been implicated in tumor progression, but the underlying molecular mechanisms remain largely unknown. Transforming growth factor-β1 (TGF-β1) exhibits cytostatic and apoptotic effects in hepatocytes and several types of hepatocellular carcinoma (HCC) cell lines, and deregulation of its signaling pathway is linked to hepatic tumorigenesis. In the present study, we observed that HO-1 is expressed at higher levels in HCC tissues than in paired normal tissues. Moreover, TGF-β1-induced cell cycle arrest and up-regulation of cyclin-dependent kinase inhibitors in HCC cell lines were significantly attenuated by overexpression of HO-1 or treatment with tricarbonyldichlororuthenium(II) dimer ([Ru(CO)3Cl2]2, suggesting an inhibitory role of the HO-1/CO axis in TGF-β signaling to growth inhibition in HCC cell lines. Interestingly, we observed that [Ru(CO)3Cl2]2 inhibits TGF-β1-induced Smad3-dependent reporter activity without affecting its C-terminus phosphorylation, complex formation with Smad4, and nuclear translocation. Additional experiments revealed that HO-1/CO axis selectively induces phosphorylation of Smad3 at Thr-179 residue in the linker region through activation of extracellular signal-activated kinase (ERK) 1/2. Transfection with a phospho-deficient Smad3 (T179A) mutant or treatment with FR180204, a specific inhibitor for ERK1/2, significantly reversed the inhibitory effects of HO-1 and [Ru(CO)3Cl2]2 on cell cycle arrest induced by TGF-β1. These findings for the first time demonstrate that HO-1/CO axis confer resistance of HCC cells to TGF-β growth inhibitory signal by increasing Smad3 phosphorylation at Thr-179 via ERK1/2 pathway.

PU.1/microRNA-142-3p targets ATG5/ATG16L1 to inactivate autophagy and sensitize hepatocellular carcinoma cells to sorafenib

Sorafenib is currently the only systemic agent approved for treatment of advanced hepatocellular carcinoma (HCC). However, intrinsic and acquired resistance to sorafenib remains a great challenge with respect to improving the prognoses of patients with HCC. The cyto-protective functions of autophagy have been suggested as a potential mechanism by which chemoresistance or targeted drug resistance occurs in tumour cells. In the present study, miR-142-3p was identified as a novel autophagy-regulating microRNA (miRNA) that plays a vital role in sorafenib resistance in HCC cells. Gain- and loss-of-function assays revealed that ectopic miR-142-3p upregulation sensitized HCC cells to sorafenib by reducing sorafenib-induced autophagy, enhancing sorafenib-induced apoptosis and inhibiting cell growth, whereas miR-142-3p inhibition exerted contrasting effects. Bioinformatics analysis and luciferase reporter and rescue assays showed that autophagy-related 5 (ATG5) and autophagy-related 16-like 1 (ATG16L1) are potential targets through which miR-142-3p regulates autophagy inhibition. Furthermore, we verified that PU.1 regulated the expression of miR-142-3p in conjunction with our cellular experiments and the related results in the literature. Our findings show that targeting the PU.1–miR-142-3p–ATG5/ATG16L1 axis may be a useful therapeutic strategy for preventing cyto-protective autophagy to overcome sorafenib resistance.

Oxidative phosphorylation activation is an important characteristic of DOX resistance in hepatocellular carcinoma cells

BackgroundDespite the implications for tumor growth and cancer drug resistance, the mechanisms underlying differences in energy metabolism among cells remain unclear.MethodsTo analyze differences between cell types, cell viability, ATP and α-ketoglutaric acid levels, the oxygen consumption rate and extracellular acidification rate, and the expression of key enzymes involved in α-KG metabolism and transfer were examined. Additionally, UPLC-MS/MS was used to determine the doxorubicin (DOX) content in SMMC-7721 and SMMC-7721/DOX cells.ResultsWe found that energy metabolism in SMMC-7721 cells is mainly dependent on the glycolysis pathway, whereas SMMC-7721/DOX cells depend more heavily on the oxidative phosphorylation pathway. Cell viability and intracellular ATP levels in SMMC-7721/DOX cells were significantly reduced by rotenone and oligomycin, inhibitors of oxidative phosphorylation. However, SMMC-7721 cell properties were more strongly influenced by an inhibitor of glycolysis, 2-deoxy-d-glucose. Furthermore, the suppressive effect of α-KG on ATP synthase plays an important role in the low levels of oxidative phosphorylation in SMMC-7721 cells; this effect could be strengthened by the metabolic poison methotrexate and reversed by l-(−)-malic acid, an accelerator of the malate-aspartate cycle.ConclusionsThe inhibitory effect of α-KG on ATP synthase was uncoupled with the tricarboxylic acid cycle and oxidative phosphorylation in SMMC-7721 cells; accordingly, energy metabolism was mainly determined by glycolysis. In drug-resistant cells, a remarkable reduction in the inhibitory effects of α-KG on ATP synthase resulted in better coordination among the TCA cycle, oxidative phosphorylation, and glycolysis, providing novel potential strategies for clinical treatment of liver cancer resistance.

Baicalein sensitizes hepatocellular carcinoma cells to 5-FU and Epirubicin by activating apoptosis and ameliorating P-glycoprotein activity

Hepatocellular carcinoma (HCC) has a dismal prognosis in part because of multi-drug resistance (MDR). Baicalein is a flavonoid extracted from Radix Scutellariae with anti-HCC activity. We tested the effects of Baicalein on multi-drug resistant HCC cells (Bel7402/5-FU) known to be resistant to the anticancer drugs 5-FU and Epirubicin. Flow cytometry analysis showed that treatment with 5 μg/ml and 10 μg/ml Baicalein resulted in increases in the intra-cellular concentrations of Rho123 and Epirubicin in the corresponding group of cells compared to untreated cells, illustrating that Baicalein reverses MDR in Bel7402/5-FU cells. Bel7402/5-FU cells displayed increased P-glycoprotein (P-gp)-mediated drug efflux. However, this efflux was inhibited in cells pre-incubated in Baicalein for 48 h. Moreover, Baicalein induced apoptosis and autophagy and decreased P-gp and Bcl-xl expression levels. All of these results indicate that Baicalein can reverse P-gp-mediated MDR in HCC and may thus be useful for the treatment of drug-resistant HCC.

Four-and-a-half LIM protein 1 promotes paclitaxel resistance in hepatic carcinoma cells through the regulation of caspase-3 activation.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. To investigate the mechanisms of paclitaxel resistance in hepatocellular carcinoma cells and find promising molecular target for HCC therapy. To investigate the effects of FHL1 on chemo resistance in HCC cells, we generated FHL1 knock-down stable cell lines with HepG2 and SMMC7721 cells. Cell viability assay, colony formation and xenograft experiments assay were performed to detect effect of FHL1 on Paclitaxel or Oxaliplatin resistance in vitro and in vivo. Caspase activity assay was performed to explore the activation of caspase-3 and caspase-9 in paclitaxel treated FHL1-knockdown HepG2 cells. In the present study we have investigated that four-and-a-half LIM protein 1 (FHL1), which plays an important role in the development of cancer, is associated with both the chemo resistance of hepatocellular carcinomas cells in vitro and in vivo. Knockdown of FHL1 significantly enhanced the sensitivity of paclitaxel, but had no effects on sensitivity of oxaliplatin. Moreover, knockdown of FHL1 promoted the activation of caspase-3 and caspase-9, which were induced by paclitaxel. Interestingly, FHL1 negatively regulates the chemo resistance of HCC in xenografted nude mice. FHL1 promote paclitaxel resistance in hepatocellular carcinomas cells through regulating apoptosis induced by paclitaxel, suggesting that FHL1 may be a promising molecular target for HCC therapy.

Secretory Clusterin Mediates Oxaliplatin Resistance via the Gadd45a/PI3K/Akt Signaling Pathway in Hepatocellular Carcinoma.

Purpose: Systemic therapy has often been used for patients with advanced hepatocellular carcinoma (HCC). However, due to drug resistance, the use of cytotoxic chemotherapy in the treatment of patients with advanced HCC has typically demonstrated low response rates. Secretory clusterin (sCLU) is expressed in aggressive late-stage tumors and associated with resistance to chemotherapy, including that in HCC cases. The present research aimed to investigate the biological role of sCLU in HCC.Methods: sCLU expression in HCC and normal tissues was examined using immunohistochemical staining, followed by analysis of the correlation between sCLU expression and clinical indicators. In addition, the role and internal mechanism of sCLU in cell proliferation and apoptosis were investigated in HCC cells.Results: sCLU expression was significantly upregulated in HCC tissues; and was associated with histological grade and poor overall survival. The levels of sCLU were significantly increased in Bel7402, SMMC7721 and resistant HCC cells (Bel7404-OR). Inhibiting the activity of sCLU enhanced the chemosensitivity of Bel7402 and SMMC7721 cells. Downregulation of sCLU could increase the expression of Gadd45a in HCC cells. Overexpression of sCLU contributed to drug resistance in Bel7402, SMMC7721 and Bel7404-OR cells; whereas, overexpression of Gadd45a alone overcame drug resistance in the cells above. No significant expression changes of sCLU and Gadd45a were observed in HCC cells after the interference of a selective inhibitor of the PI3K/Akt signaling pathway. However, regulation of the expression of Gadd45a could influence the phosphorylation level of Akt; and further regulate the expression of Bcl-2 and Bax proteins involved in the mitochondrial apoptosis pathways.Conclusions: The results demonstrate that sCLU/Gadd45a/PI3K/Akt signaling represents a novel pathway that could regulate drug resistance in a one-way manner in HCC cells.

Cancer stem cells in hepatocellular carcinoma: an overview and promising therapeutic strategies.

The poor clinical outcome of hepatocellular carcinoma (HCC) patients is ascribed to the resistance of HCC cells to traditional treatments and tumor recurrence after curative therapies. Cancer stem cells (CSCs) have been identified as a small subset of cancer cells which have high capacity for self-renewal, differentiation and tumorigenesis. Recent advances in the field of liver CSCs (LCSCs) have enabled the identification of CSC surface markers and the isolation of CSC subpopulations from HCC cells. Given their central role in cancer initiation, metastasis, recurrence and therapeutic resistance, LCSCs constitute a therapeutic opportunity to achieve cure and prevent relapse of HCC. Thus, it is necessary to develop therapeutic strategies to selectively and efficiently target LCSCs. Small molecular inhibitors targeting the core stemness signaling pathways have been actively pursued and evaluated in preclinical and clinical studies. Other alternative therapeutic strategies include targeting LCSC surface markers, interrupting the CSC microenvironment, and altering the epigenetic state. In this review, we summarize the properties of CSCs in HCC and discuss novel therapeutic strategies that can be used to target LCSCs.

Low expression of NKD2 is associated with enhanced cell proliferation and poor prognosis in human hepatocellular carcinoma

NKD2 is a member of the Naked cuticle (Nkd) protein family and functions as a negative regulator of the Wnt signaling pathway. We investigated the prognostic value of NKD2 expression in hepatocellular carcinoma (HCC). Western blot and immunohistochemical analyses revealed that NKD2 was significantly downregulated in HCC specimens compared with adjacent nontumorous tissues. Next, we found that NKD2 expression correlated significantly with several clinicopathologic features, such as tumor grade, tumor size, and Ki-67 expression. Univariate and multivariate analyses demonstrated that NKD2 was an independent prognostic factor for the survival of HCC patients. In particular, Kaplan-Meier survival curves suggested that low NKD2 was statistically associated with poor overall survival. Furthermore, serum refeeding of cultured HCC cells led to impaired amounts of NKD2 and induced HepG2 and Huh7 cells to transition from the G1 to the S phase. Small interfering RNA-mediated depletion of NKD2 in LO2 hepatocytes caused accelerated cell growth. To further clarify the role of NKD2 in cell cycle progression, a Flag-tagged NKD2 construct was used to overexpress NKD2 exogenously in Huh7 cells. These results showed that overexpression of NKD2 induced G1-phase cell cycle arrest. Reduced expression of NKD2 correlated with hyperactivation of the Wnt/β-catenin pathway and doxorubicin resistance in HCC cells. On the basis of these findings, we conclude that NKD2 may be a novel prognostic marker and therapeutic target in HCC.