Optimal therapy for patients with hepatocellular carcinoma and resistance or intolerance to sorafenib: challenges and solutions

Prexasertib exerts a synergistic effect on the antitumor activity of Lenvatinib through ALOX15-mediated ferroptosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal malignancies worldwide. Lenvatinib, a potent multi-receptor tyrosine kinase inhibitor approved for the treatment of advanced HCC, demonstrates limited clinical efficacy. Therefore, there is an urgent need to investigate therapeutic strategies that combine Lenvatinib with other anticancer agents. Lenvatinib induces DNA damage in tumor cells, and the inhibition of the DNA damage response (DDR) pathway is hypothesized to enhance Lenvatinib-induced tumor cell death. In this study, we initially observed that Lenvatinib upregulated phosphorylated checkpoint kinase 1 (CHK1) protein levels, a key molecule in the DDR pathway, in HCC cells. This observation prompted us to investigate the antitumor efficacy of combining Lenvatinib with Prexasertib, a novel CHK1 inhibitor. The combination demonstrated synergistic anticancer effects in HCC cells. Mechanistically, treatment with Lenvatinib and Prexasertib resulted in cell death primarily through ferroptosis. Furthermore, we found that Lenvatinib and Prexasertib cooperatively upregulated ALOX15 expression, which culminated in the induction of ferroptosis. Taken together, our findings suggest the potential application of Prexasertib in combination with Lenvatinib as a promising therapeutic strategy for HCC treatment.

The Role of Bcl-2 Family Proteins and Sorafenib Resistance in Hepatocellular Carcinoma

Liver cancer has been reported to be one of the most malignant diseases in the world. It is late diagnosis consequently leads to a difficult treatment, as the cancer reached an advanced stage. Hepatocellular carcinoma (HCC) is the primary type of cancer diagnosed in the liver, with deadly characteristics and a poor prognosis. The first-in-line treatment for advanced HCC is sorafenib. Sorafenib acts by inhibiting cell proliferation and by inducing apoptosis as well as blocks receptors associated with these mechanisms. Due to its constant use, sorafenib resistance has been described, especially to proteins of the Bcl-2 family, and their overexpression of Bcl-XL and Mcl-1. This review focuses on the role of the Bcl-2 proteins in relation to sorafenib resistance as a consequence of first-in-line treatment in HCC.

Purpurogallin carboxylic acid exhibits synergistic effects with 5‑fluorouracil on liver cancer cells in vitro by targeting ABCG2

Purpurogallin carboxylic acid (PCA) is a natural phenol compound derived from Macleaya microcarpa (Maxim.) Fedde, which exerts particular antioxidant and anti-inflammatory capacities. However, the effects and mechanisms of PCA on liver cancer cells remain unknown. Therefore, network pharmacology and computer virtual docking were used to identify the target-proteins of PCA. In addition, surface plasmon resonance, protease activity and rhodamine excretion assays were carried out to evaluate the effects of PCA on the activity of ATP binding cassette subfamily G member 2 (ABCG2). The synergistic effects of PCA and 5-fluorouracil (5-FU) on liver cancer cell proliferation, cell cycle arrest, colony formation and spheroid formation abilities in vitro were determined by Cell Counting Kit-8 (CCK-8) assay, flow cytometry, western blot analysis, colony formation and spheroid formation assays, respectively. ABCG2 was identified as a potential target of PCA, with a high docking score. The equilibrium dissociation constant of PCA for ABCG2 protein was 1.84 µM, while the median inhibitory concentration of this protein was 3.09 µM. In addition, the results demonstrated that PCA could significantly reduce the drug efflux capacity of liver cancer cells. CCK-8 assays revealed that liver cancer cell treatment with 10 µM PCA and 10 µM 5-FU exhibited the most potent synergistic effects on liver cancer cell proliferation at 48 h. Additionally, cell co-treatment with PCA and 5-FU also significantly attenuated the colony and spheroid formation abilities of liver cancer cells in vitro, while it promoted their arrest at the G1 phase of the cell cycle. Furthermore, ABCG2 silencing in liver cancer cells notably abrogated the synergistic effects of PCA and 5-FU. In conclusion, the present study demonstrated that PCA exhibited synergistic effects with 5-FU on liver cancer cells in vitro via targeting ABCG2. Therefore, PCA combined with 5-FU may be a potential strategy for liver cancer therapy.

Qualitative evaluation of barriers and facilitators to hepatocellular carcinoma care in North Carolina

BACKGROUND

Many patients with hepatocellular carcinoma (HCC) never receive cancer-directed therapy. In order to tailor interventions to increase access to appropriate therapy, we sought to understand the barriers and facilitators to HCC care.

METHODS

Patients with recently diagnosed HCC were identified through the University of North Carolina (UNC) HCC clinic or local hospital cancer registrars (rapid case ascertainment, RCA). Two qualitative researchers conducted in-depth, semi-structured interviews. Interviews were audiotaped, transcribed, and coded.

RESULTS

Nineteen interviews were conducted (10 UNC, 9 RCA). Key facilitators of care were: physician knowledge; effective communication regarding test results, plan of care, and prognosis; social support; and financial support. Barriers included: lack of transportation; cost of care; provider lack of knowledge about HCC; delays in scheduling; or poor communication with the medical team. Participants suggested better coordination of appointments and having a primary contact within the healthcare team.

LIMITATIONS

We primarily captured the perspectives of those HCC patients who, despite the challenges they describe, were ultimately able to receive HCC care.

CONCLUSIONS

This study identifies key facilitators and barriers to accessing care for HCC in North Carolina. Use of the RCA system to identify patients from a variety of settings, treated and untreated, enabled us to capture a broad range of perspectives. Reducing barriers through improving communication and care coordination, assisting with out-of-pocket costs, and engaging caregivers and other medical providers may improve access. This study should serve as the basis for tailored interventions aimed at improving access to appropriate, life-prolonging care for patients with HCC.

Effects of Sorafenib and Quercetin Alone or in Combination in Treating Hepatocellular Carcinoma: In Vitro and In Vivo Approaches

Sorafenib is the first drug approved to treat advanced hepatocellular carcinoma (HCC) and continues as the gold-standard therapy against HCC. However, acquired drug resistance represents a main concern about sorafenib therapy. The flavanol quercetin found in plants has shown great anti-cancer and anti-inflammatory properties. In this work, quercetin was used as a therapeutic agent alone or in combination with a sorafenib chemotherapy drug to improve the routine HCC treatment with sorafenib. The in vitro and in vivo results presented here confirm that quercetin alone or in combination with sorafenib significantly inhibited HCC growth, induced cell cycle arrest and induced apoptosis and necrosis. Further molecular data shown in this report demonstrate that quercetin alone or combined with sorafenib downregulated key inflammatory, proliferative and angiogenesis-related genes (TNF-α, VEGF, P53 and NF-κB). Combined quercetin/sorafenib treatment markedly improved the morphology of the induced liver damage and showed significant antioxidant and anti-tumor effects. The advantage of combined treatment efficacy reported here can be attributed to quercetin's prominent effects in modulating cell cycle arrest, apoptosis, oxidative stress and inflammation.

LncRNA AC026401.3 interacts with OCT1 to intensify sorafenib and lenvatinib resistance by activating E2F2 signaling in hepatocellular carcinoma

Multitargeted kinase inhibitors (MKIs) including sorafenib and lenvatinib, are applied for first-line treatment for inoperable hepatocellular carcinoma (HCC) patients, but the therapeutic effect is limited because of drug resistance. Therefore, we sought potential biomarkers to indicate sorafenib and lenvatinib resistance in HCC. In this article, we report a novel long non-coding RNA (lncRNA), AC026401.3, in promoting sorafenib and lenvatinib resistance of HCC cells. AC026401.3 is upregulated in HCC tissues and is positively relevant to HCC patients with large tumor size, cancer recurrence, advanced TNM stage, and poor prognosis. AC026401.3 knockdown or knockout enhances the sensitivity of HCC cells to sorafenib and lenvatinib, respectively. Moreover, AC026401.3 upregulates the expression of the transcription factor E2F2. Mechanistically, AC026401.3 interacts with OCT1 and promotes the recruitment of OCT1 to the promoter region of E2F2, intensifying sorafenib and lenvatinib resistance in HCC by activating the transcription of E2F2. In conclusion, our results reveal that lncRNA AC026401.3 is a risk factor for HCC patients by enhancing sorafenib and lenvatinib resistance of HCC cells, and targeting the AC026401.3-OCT1-E2F2 signaling axis would be a promising strategy for HCC therapeutics.

Liver cancer heterogeneity modeled by in situ genome editing of hepatocytes

Mechanistic study and precision treatment of primary liver cancer (PLC) are hindered by marked heterogeneity, which is challenging to recapitulate in any given liver cancer mouse model. Here, we report the generation of 25 mouse models of PLC by in situ genome editing of hepatocytes recapitulating 25 single or combinations of human cancer driver genes. These mouse tumors represent major histopathological types of human PLCs and could be divided into three human-matched molecular subtypes based on transcriptomic and proteomic profiles. Phenotypical characterization identified subtype- or genotype-specific alterations in immune microenvironment, metabolic reprogramming, cell proliferation, and expression of drug targets. Furthermore, single-cell analysis and expression tracing revealed spatial and temporal dynamics in expression of pyruvate kinase M2 (Pkm2). Tumor-specific knockdown of Pkm2 by multiplexed genome editing reversed the Warburg effect and suppressed tumorigenesis in a genotype-specific manner. Our study provides mouse PLC models with defined genetic drivers and characterized phenotypical heterogeneity suitable for mechanistic investigation and preclinical testing.

Adverse events of sorafenib in hepatocellular carcinoma treatment

Sorafenib is an oral multikinase inhibitor approved by the US Food and Drug Administration for treatment of the patients with surgically unresectable hepatocellular carcinoma (HCC). Sorafenib mitigates angiogenesis by targeting vascular endothelial growth factor receptors and platelet-derived growth factor receptors in endothelial cells and pericytes. Moreover, it suppresses cell proliferation via blockage of B-RAF and RAF1 of the mitogen-activated protein kinase pathway in tumor cells. Sorafenib has been the standard molecular targeted medication in the treatment of advanced-stage HCC patients ineligible for potentially curative interventional (radiofrequency or microwave ablation) or palliative trans-arterial chemoembolization (TACE) therapies for over a decade. However, it only increases overall survival by less than 3 months, and systemic exposure to sorafenib causes clinically significant toxicities (about 50% of patients). Given the high frequency and severity of these toxicities, sorafenib dose must be often reduced or discontinued altogether. In this review, we discussed the mechanism of sorafenib-associated adverse events and their management during HCC treatment.

AXL and MET in Hepatocellular Carcinoma: A Systematic Literature Review

BACKGROUND

Multikinase inhibitors (MKIs) have been shown to improve survival in patients with hepatocellular carcinoma (HCC) compared with placebo. Distinct from other MKIs, cabozantinib has inhibitory activity for both AXL and MET. This review considers the literature elucidating the role of AXL and MET in HCC progression, treatment resistance, and immunomodulation. A systematic search of the PubMed database was conducted on November 16, 2020, and identified a total of 174 search results. A further 36 potentially relevant articles were identified based on the authors' knowledge. After initial screening by title/abstract, 159 underwent full-text screening and we identified 69 original research articles reporting empirical data from in vitro or in vivo models of HCC evaluating the effects of manipulating AXL or MET signaling on tumorigenic behavior.

SUMMARY

AXL expression is highly correlated with HCC progression and outcomes and has been reported to be involved in transforming growth factor-β and the regulation of PI3K/AKT, ERK/MAPK, and CCN proteins. MET protein expression is increased in HCC with the highest histological grade and has been reported to be involved in the regulation of PI3K/AKT, PLCγ/DAG/PKC, and MAPK/ERK signaling. Both AXL and MET are key regulators of sorafenib resistance in HCC. In terms of immunomodulation, there are data to indicate that AXL and MET interact with the immune components of the tumor microenvironment and promote tumorigenesis and treatment resistance. In addition, AXL was found to play a potential role in the development of a protumorigenic neutrophil phenotype in HCC. Combined inhibition of MET and programmed cell death protein resulted in additive reduction of HCC cell growth.

KEY MESSAGES

AXL and MET play key roles in HCC progression, treatment resistance, and immunomodulation. Continued development of drugs that target these receptor tyrosine kinases appears likely to represent a useful strategy to improve outcomes for patients with HCC.

Stereotactic body radiation therapy versus radiofrequency ablation in patients with small hepatocellular carcinoma: a systematic review and meta-analysis

Background

This study aimed to compare the clinical outcomes and toxicity between small hepatocellular carcinoma (HCC) patients treated with stereotactic body radiation therapy (SBRT) and those treated with radiofrequency ablation (RFA).

Methods

We searched databases for relevant clinical studies. The primary outcomes of interest were overall survival (OS) at 1 and 2 years, freedom from local progression (FFLP) rate at 2 years, and complications.

Results

Five cohorts from 5 retrospective studies and 4,814 patients with HCC were included. Pooled OS at 2 years was significantly lower for SBRT than for RFA [odds ratio (OR): 0.63; 95% confidence interval (CI): 0.51-0.79; P<0.0001], but the pooled FFLP rate at 2 years was higher for SBRT than for RFA (OR: 1.66; 95% CI: 1.05-2.61; P=0.03). In addition, there was no significant difference in the local and liver toxicities of the two treatments. The contradictory conclusion between the OS and FFLP outcome may be attributed to the difference in radiological dose and location, but there were no uniform criteria to illustrate the radiological dose and location in the included studies.

Conclusions

SBRT had a higher local control ratio but poorer prognosis than RFA in patients with small HCC. The local toxicity was comparable in both treatments. Further trials should be designed with uniform standards for SBRT and RFA treatments.

Underlying mechanism of sorafenib resistance in hepatocellular carcinoma: a bioinformatics study based on validated resistance-related genes

Background

Sorafenib, the first approved targeted therapy for advanced hepatocellular carcinoma (HCC), is often reported to comprised survival-benefit due to resistance. An underlying mechanism of resistance was proposed using bioinformatics analysis based on differentially expressed genes (DEGs) from microarrays. However, most DEGs were invalidated at both the expression level, and the role in causing resistance. Therefore, we conducted a bioinformatics analysis based on experimentally determined sorafenib-resistance-related genes (SRRGs) to elucidate the mechanism of sorafenib resistance.

Methods

The SRRGs, which have been experimentally determined to promote or inhibit resistance, were collected from published studies. The Database for Annotation, Visualization and Integrated Discovery (DAVID) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to perform Gene Ontology (GO) and pathway enrichment analysis, respectively. A corresponding protein-protein interaction network (PPI) was created using the Cytoscape software program, and network hub genes were proposed.

Results

A total of 145 SRRGs, with 117 promoting and 28 inhibiting resistance, were identified. Cell proliferation, migration, development, response to oxygen levels, epithelial-to-mesenchymal transition (EMT), cell skeleton, protein function, and autophagy were all proposed as crucial gene functions related to resistance. The pathways related to cell proliferation or apoptosis, immune function, endocrine metabolism, stem cell function, and differentiation were identified as key resistance-related pathways. A total of 81 hub genes were proposed, including the following top 10 genes: TP53, AKT1, EGFR, STAT3, VEGFA, JUN, MAPK1, IL6, PTEN, and CTNNB1.

Conclusions

In conclusion, this study gathered experimentally validated genes that determine sorafenib resistance in HCC, provided an overview of the underlying mechanisms of resistance, and further validated sorafenib resistance in HCC.

The selective serotonin reuptake inhibitors enhance the cytotoxicity of sorafenib in hepatocellular carcinoma cells

Sertraline and fluoxetine are the two most commonly used selective serotonin reuptake inhibitors (SSRIs) in the treatment of depression. Accumulating evidence has revealed that SSRIs can reduce the risk of hepatocellular carcinoma (HCC), but their therapeutic effects in HCC have not yet been elucidated. Previous studies have reported that sertraline and fluoxetine can suppress the growth of gastric carcinoma, melanoma and nonsmall cell lung cancers by inhibiting the mammalian target rapamycin (mTOR) activity. In this study, we found that sertraline and fluoxetine blocked the protein kinase B (AKT)/mTOR pathway and suppressed the growth of HCC cells in vitro, in xenografts and in diethylnitrosamine/carbon tetrachloride (DEN/CCL4)-induced primary liver mouse model. Sertraline and fluoxetine can synergize with sorafenib, the first approved standard therapy for advanced HCC, to inhibit the viability of HCC cells in vitro and in vivo. In addition, the combination of sorafenib and SSRIs synergistically inhibited the effects of the AKT/mTOR pathway. These results reveal novel therapeutic effects of a combination of SSRIs and sorafenib in HCC.

Phenformin synergistically sensitizes liver cancer cells to sorafenib by downregulating CRAF/ERK and PI3K/AKT/mTOR pathways

Sorafenib is a first-line drug to treat advanced hepatocellular carcinoma (HCC), which can prolong the median overall survival of patients by approximately 3 months. Phenformin is a biguanide derivative that has been shown to exhibit antitumor activity superior to that of metformin. We herein explored the ability of phenformin to enhance the anti-cancer activity of sorafenib against HCC and the mechanisms underlying such synergy. The Hep-G2 and SMMC-7721 HCC cell lines were treated with sorafenib and/or phenformin, after which the proliferation of these cells was evaluated via MTT and colony formation assays, while invasion and apoptotic cell death were evaluated via Transwell and flow cytometry assays, respectively. In addition, protein levels were assessed by Western blotting, drug synergy was assessed with the CompuSyn software, and xenograft models were established by implanting Hep-G2 cells into nude mice and then assessing drug antitumor efficacy. Sorafenib and phenformin exhibited a synergistic ability to suppress HCC cell proliferation, migration, and survival. Phenformin further bolstered the ability of sorafenib to inhibit the CRAF/ERK and PI3K/AKT/mTOR pathways. Strikingly, the combination of these two drugs achieved better in vivo efficacy in a murine model system, without causing significant weight loss or hepatorenal toxicity. Sorafenib and phenformin can synergistically suppress CRAF/ERK and PI3K/AKT/mTOR pathway activation in HCC cells, and may thus represent a promising approach to treating this deadly cancer.

Quercetin induces apoptosis and enhances gemcitabine therapeutic efficacy against gemcitabine-resistant cancer cells

Quercetin, an abundant flavonoid found in various fruits and vegetables, displays multiple biological activities, including anticancer effects. Therefore, quercetin is receiving increasing attention as a potential adjuvant anticancer treatment. Gemcitabine (GEM) resistance is a major issue for clinicians and patients with advanced cancers, making it crucial to determine ways to bolster its effects. In this study, we explored the anticancer effects and mechanistic actions of quercetin in GEM-resistant cancer cells. Pancreatic cancer (BxPC-3, PANC-1) and hepatocellular carcinoma (HepG2, Huh-7) cell lines were studied. Proliferation assays showed that quercetin had cytotoxic effects on GEM-resistant cell lines (HepG2 and PANC-1), and flow cytometric analysis indicated a significant pro-apoptotic effect on these cell lines. GEM treatment, in combination with quercetin, resulted in increased anticancer effects compared with GEM alone. Quercetin led to S phase arrest in GEM-resistant cell lines, and western blot analysis revealed tumour protein p53 upregulation and cyclin D1 downregulation. This study provides mechanistic insight into the anticancer effects of quercetin and suggests that quercetin adjuvant treatment may benefit patients who are resistant to GEM therapy.

Actin-binding protein anillin promotes the progression of hepatocellular carcinoma in vitro and in mice

Hepatocellular carcinoma (HCC) is a common type of tumor with high mortality worldwide. Investigations associated with the molecular etiology of HCC and screening novel therapeutic targets are still urgently in need. Anillin (ANLN), as a type of evolutionarily conserved actin-binding protein, is involved in multiple cellular processes. ANLN widely affected the progression and metastasis of several types of cancer, and its overexpression was frequently demonstrated in previous studies. The present study demonstrated high expression of ANLN in human HCC tissues, which was also associated the prognosis of patients with HCC. The associations between ANLN expression and the clinicopathological features were determined, including the number of tumor nodes (P=0.011) and tumor size (P=0.003) of patients with HCC. It was found that ANLN promoted cell proliferation, invasion and migration of HCC cells in vitro, and affected tumor growth in vivo. Therefore, ANLN is suggested as a promising therapeutic target for the treatment of HCC.

AG-1024 Sensitizes Sorafenib-Resistant Hepatocellular Carcinoma Cells to Sorafenib via Enhancing G1/S Arrest

PURPOSE

The frequency in resistance to sorafenib accounts for the grim prognosis of advanced hepatocellular carcinoma (HCC). In the present study, we explore the anti-cancer efficacy of co-administration of sub-toxic AG-1024 with sorafenib in HCC cells to enhance the sensitivity of these cells to sorafenib.

MATERIALS AND METHODS

Two acquired sorafenib-resistant HCC cells, SNU-sora-5 and SK-sora-5, were established and verified. The MTT assay, colony formation assay, cell morphology detection and flow cytometric analysis were then used to determine the anti-tumor effects of the co-administration of sub-toxic AG-1024 and sorafenib. Finally, the potential molecular mechanism was preliminarily examined.

RESULTS

Compared to parental cell lines, the acquired sorafenib-resistant cell lines, SNU-sora-5 and SK-sora-5, were more resistant to sorafenib. Sub-toxic AG-1024 markedly enhanced sorafenib-mediated cell inhibition in acquired sorafenib-resistant HCC strains, with a reversal index (RI) of 4.64 in SNU-sora-5 and 4.58 in SK-sora-5 cell lines. Moreover, co-administration of sub-toxic AG-1024 and sorafenib exerted dramatic cytotoxicity compared with sorafenib alone in the intrinsic sorafenib-resistant HCC-LM3 cells. In contrast to high-dose sorafenib, sub-toxic AG-1024 combined with sorafenib had less impact on apoptosis while significantly enhancing G1/S arrest via activation of the mTOR/p21 signaling pathway. The more, pharmacological inhibition of mTOR activity by inhibitor Palomid 529 significantly antagonized the synergistic anti-cancer effects of AG-1024 and sorafenib in HCC cells.

CONCLUSION

The current findings indicate that sub-toxic AG-1024 may be a promising therapeutic agent in enhancing the sensitivity in HCC cells to sorafenib, bringing hope to HCC patients refractory to sorafenib treatment.

Actin-binding protein Anillin promotes the progression of gastric cancer in vitro and in mice

BACKGROUND

To detect the expression levels of actin-binding protein anillin (ANLN) in human gastric cancer (GC) tissues and explore the possible involvement of ANLN in GC cell proliferation, migration, and invasion.

METHODS

The bioinformation analysis was performed in TCGA database to explore the expression of ANLN in human GC tissues and the difference of ANLN expression between multiple types of cancers. IHC assays and clinical pathological analysis were performed to confirm ANLN expression and its correlation with clinical features of GC patients. Colony formation, CCK-8, wound closure, and transwell assays were performed to detect its effects on GC cell proliferation, migration, and invasion in vitro. Tumor growth was also measured using a xenograft animal model.

RESULTS

We found the high expression of ANLN in human GC tissues based on the results from TCGA database and IHC staining. We further noticed ANLN depletion resulted in the inhibition of GC cell proliferation, migration, and invasion. Our data further confirmed that ANLN contributed to tumor growth of GC cells in vivo.

CONCLUSIONS

We confirmed the involvement of ANLN in GC progression and thought ANLN could serve as a promising therapeutic target for GC.

LncRNA TTN-AS1 intensifies sorafenib resistance in hepatocellular carcinoma by sponging miR-16-5p and upregulation of cyclin E1

Drug resistance has always been an important problem affecting the therapeutic effect of hepatocellular carcinoma (HCC). To investigate the potential role of lncRNA TTN-AS1 in HCC cells with sorafenib (SOR) resistance, and explore the underlying pathways, quantitative real time polymerase chain reaction (qRT-PCR) was used to test the expression of TTN-AS1 in HCC tissues and cells. Then, the expression of TTN-AS1 was down-regulated by shRNA, the activity changes, apoptosis and related protein expression in HCC cells with/without SOR treatment were observed in succession. Expression levels of the downstream target of TTN-AS1, miR-16-5p were studied by dual-luciferase binding assay, cell proliferation, and western blotting analysis. Nude mice models of human HCC with TTN-AS1 gene knockdown were established to observe the tumor growth. As the results revealed, TTN-AS1 silencing in HCC cells induced apoptosis by enhancing the sensitivity of cells to SOR, and the tumor in nude mice became smaller. The mechanism study showed that miR-16-5p was affected by TTN-AS1 sponge, up-regulated cyclin E1 expression, and regulated PTEN/Akt signaling pathway, thereby significantly alleviating the inhibition of apoptosis of HCC cells induced by TTN-AS1 gene. Collectively, our results provided TTN-AS1 as a potential therapeutic target for sorafenib resistance in HCC.

LY3214996 relieves acquired resistance to sorafenib in hepatocellular carcinoma cells

Background: Sorafenib, an oral multi-kinase inhibitor of rapidly accelerated fibrosarcoma; vascular endothelial growth factor receptor-2/3, platelet-derived growth factor receptor, c-Kit, and Flt-3 signaling, is approved for treatment of advanced hepatocellular carcinoma (HCC). However, the benefit of sorafenib is often diminished because of acquired resistance through the reactivation of ERK signaling in sorafenib-resistant HCC cells. In this work, we investigated whether adding LY3214996, a selective ERK1/2 inhibitor, to sorafenib would increase the anti-tumor effectiveness of sorafenib to HCC cells. Methods: The Huh7 cell line was used as a cell model for treatment with sorafenib, LY3214996, and their combination. Phosphorylation of the key kinases in the Ras/Raf/MAPK and PI3K/Akt pathways, protein expression of the cell cycle, and apoptosis migration were assessed with western blot. MTT and colony-formation assays were used to evaluate cell proliferation. Wound-healing assay was used to assess cell migration. Cell cycle and apoptosis analyses were conducted with flow cytometry. Results: LY3214996 decreased phosphorylation of the Ras/Raf/MAPK and PI3K/Akt pathways, including p-c-Raf, p-P90RSK, p-S6K and p-eIF4EBP1 activated by sorafenib, despite increased p-ERK1/2 levels. LY3214996 increased the anti-proliferation, anti-migration, cell-cycle progression, and pro-apoptotic effects of sorafenib on Huh7^R cells. Conclusions: Reactivation of ERK1/2 appears to be a molecular mechanism of acquired resistance of HCC to sorafenib. LY3214996 combined with sorafenib enhanced the anti-tumor effects of sorafenib in HCC. These findings form a theoretical basis for trial of LY3214996 combined with sorafenib as second-line treatment of sorafenib-resistant in advanced HCC.

Cytochrome P450 1A2 overcomes nuclear factor kappa B-mediated sorafenib resistance in hepatocellular carcinoma

Sorafenib resistance has become the main obstacle in the effective treatment of advanced hepatocellular carcinoma (HCC) patients. Activation of nuclear factor kappa B (NF-κB) is a newly identified mechanism that contributes to desensitized sorafenib. Cytochrome P450 1A2 (CYP1A2) functions as a tumor suppressor in HCC and its expression is negatively associated with NF-κB in the liver. This study aimed to study whether CYP1A2 could overcome sorafenib resistance. To investigate whether CYP1A2 and NF-κB p65 played roles in sorafenib desensitization, we established sorafenib-resistant (SR) HCC cells. SR cells decreased the expression of CYP1A2 along with the upregulation of NF-κB p65. CYP1A2 overexpression attenuated SR cell proliferation, increased sorafenib sensitivity, and inhibited the NF-κB pathway, whereas CYP1A2 silence showed opposite effects. Sorafenib, in combination with omeprazole, a CYP1A2 inducer, significantly hindered the growth and invasion of SR cells in vitro as well as decreased the tumor growth in vivo. The combination treatment markedly increased CYP1A2 expression and inhibited the sorafenib-induced NF-κB signaling. In addition, the overexpression of NF-κB p65 stimulated the SR cell growth and desensitized sorafenib in SR cells, where CYP1A2 overexpression reversed the phenomenon. Lastly, the majority of HCC tissue samples displayed decreased CYP1A2 but increased NF-κB p65 protein expression. Collectively, CYP1A2 can sensitize SR cells to sorafenib via inhibiting NF-κB p65 axis. Omeprazole in combination with sorafenib exerts a synergistic effect in alleviating acquired sorafenib resistance.

Gut Microbiota, Peroxisome Proliferator-Activated Receptors, and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. HCC incidence rate is sixth and mortality is fourth worldwide. However, HCC pathogenesis and molecular mechanisms remain unclear. The incidence of HCC is associated with genetic, environmental, and metabolic factors. The role of gut microbiota in the pathogenesis of HCC has attracted researchers' attention because of anatomical and functional interactions between liver and intestine. Studies have demonstrated the involvement of gut microbiota in the development of HCC and chronic liver diseases, such as alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), and liver cirrhosis. Peroxisome proliferator-activated receptors (PPARs) are a group of receptors with diverse biological functions. Natural and synthetic PPAR agonists show potential for treatment of NAFLD, liver fibrosis, and HCC. Recent studies have demonstrated that PPARs take part in gut microbiota inhabitation and adaptation. This manuscript reviews the role of gut microbiota in the development of HCC and precancerous diseases, the role of PPARs in modulation of gut microbiota and HCC, and potential of gut microbiota for HCC diagnosis and treatment.

The miR-30a-5p/CLCF1 axis regulates sorafenib resistance and aerobic glycolysis in hepatocellular carcinoma

HCC (hepatocellular carcinoma) is a major health threat for the Chinese population and has poor prognosis because of strong resistance to chemotherapy in patients. For instance, a considerable challenge for the treatment of HCC is sorafenib resistance. The aberrant glucose metabolism in cancer cells aerobic glycolysis is associated with resistance to chemotherapeutic agents. Drug-resistance cells and tumors were exposed to sorafenib to establish sorafenib-resistance cell lines and tumors. Western blotting and real-time PCR or IHC staining were used to analyze the level of CLCF1 in the sorafenib resistance cell lines or tumors. The aerobic glycolysis was analyzed by ECAR assay. The mechanism mediating the high expression of CLCF1 in sorafenib-resistant cells and its relationships with miR-130-5p was determined by bioinformatic analysis, dual luciferase reporter assays, real-time PCR, and western blotting. The in vivo effect was evaluated by xenografted with nude mice. The relation of CLCF1 and miR-30a-5p was determined in patients' samples. In this study, we report the relationship between sorafenib resistance and increased glycolysis in HCC cells. We also show the vital role of CLCF1 in promoting glycolysis by activating PI3K/AKT signaling and its downstream genes, thus participating in glycolysis in sorafenib-resistant HCC cells. Furthermore, we also show that miR-30a-5p directly targets CLCF1 and that sorafenib-mediated suppression of miR-30a-5p results in the upregulation of CLCF1 in HCC cells resistant to sorafenib. We also found that when a cholesterol modified agomiR-30a-5p was delivered systemically to mice harboring sorafenib-resistant HCC tumors, tumor growth decreased significantly. There is an uncharacterized mechanism of biochemical resistance to hormone therapies orchestrated by the miR-30a-5p/CLCF1 axis to mediate sorafenib resistance and aerobic glycolysis in HCC. Therefore, this study indicates that targeting the miR-30a-5p/CLCF1 axis may hold promise for therapeutic intervention in HCC sorafenib resistance patients.

GHR knockdown enhances the sensitivity of HCC cells to sorafenib

Sorafenib is approved for treatment of advanced hepatocellular carcinoma (HCC) by the Drug Administration. However, the efficacy of sorafenib has become very limited because most tumors have developed resistance to this drug. In this study, we found that sorafenib stimulated GHR expression in HCC cell lines. Thus, GHR might be linked to sorafenib resistance. To verify this hypothesis, we researched the roles of GHR knockdown and sorafenib combination in cell viability, apoptosis, cycle, and migration. The results showed that GHR blockage enhanced sorafenib blocking of cell cycle progression, leading to inhibition of this drug on HCC cell viability, and the improved promoting ability of sorafenib on cell apoptosis. In addition, it was found that GHR knockdown enhanced sorafenib inhibition of cell migration. The synergistic antitumor effects of sorafenib and GHR knockdown combination may be attributed to inhibition of PI3K/AKT/ERK1/2 signaling pathway. In conclusion, the findings suggest that GHR knockdown enhances the sensitivity of HCC cells to sorafenib. and the inactivation of PI3K/AKT/ERK1/2 signaling pathway may be the underlying mechanisms. This highlights the absence of GHR as a promising way to enhance sorafenib efficacy in HCC.

Identification of the Novel Oncogenic Role of SAAL1 and Its Therapeutic Potential in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide, affecting over 700,000 people per year. The treatment effect in advanced HCC is still disappointing and prognosis of advanced HCC remains poor. Hence, to find more effective therapeutic targets to improve the treatment outcome of HCC is of urgent need. In this study, we reported the novel oncogenic function of SAAL1 (serum amyloid A-like 1) in HCC, which previously is considered as an inflammation-related gene. We found that SAAL1 was significantly upregulated in HCC tumor tissues when compared to the adjacent normal tissues and high expression of SAAL1 correlated with shorter overall survival in The Cancer Genome Atlas (TCGA) HCC database. Functionally, we showed that the depletion of SAAL1 significantly reduced cell proliferation, 3D colony formation, and migration/invasion abilities of HCC cancer cells. Furthermore, suppression of SAAL1 impaired the HGF/Met-driven Akt/mTOR phosphorylation cascade and increased the chemosensitivity of HCC cells to sorafenib and foretinib treatment. Our data indicated that SAAL1 plays an important role in HCC via mediating oncogenic HGF/Met-driven Akt/mTOR signaling and could serve as an independent prognostic marker, as well as a promising therapeutic target for HCC patients.

Hypoxia-Induced Aquaporin-3 Changes Hepatocellular Carcinoma Cell Sensitivity to Sorafenib by Activating the PI3K/Akt Signaling Pathway

Purpose

Hypoxia-induced changes are primarily activated in patients with hepatocellular carcinoma (HCC) and long-term sorafenib exposure, thereby reducing the sensitivity to the drug. Aquaporin-3 (AQP3), a member of the aquaporin family, is a hypoxia-induced substance that affects the chemosensitivity of non-hepatocellular tumors. However, its expression and role in the sensitivity of hypoxic HCC cells to sorafenib-induced apoptosis remain unclear. The purpose of this study was to detect changes in AQP3 expression in hypoxic HCC cells and to determine whether these changes alter the sensitivity of these cells to sorafenib.

Materials and Methods

Huh7 and HepG2 hypoxic cell models were established and AQP3 expression was detected using quantitative real-time polymerase chain reaction (qPCR) and Western blotting. Furthermore, the role of AQP3 in cell sensitivity to sorafenib was evaluated via flow cytometry, Western blotting, and a CCK-8 assay.

Results

The results of qPCR and Western blotting showed that AQP3 was overexpressed in the Huh7 and HepG2 hypoxic cell models. Furthermore, AQP3 protein levels were positively correlated with hypoxia-inducible factor-1α (HIF-1α) levels. Compared with cells transfected with lentivirus-GFP (Lv-GFP), hypoxic cells transfected with lentivirus-AQP3 (Lv-AQP3) were less sensitive to sorafenib-induced apoptosis. However, the sensitivity to the drug increased in cells transfected with lentivirus-AQP3RNAi (Lv-AQP3RNAi). Akt and Erk phosphorylation was enhanced in Lv-AQP3-transfected cells. Compared with UO126 (a Mek1/2 inhibitor), LY294002 (a PI3K inhibitor) attenuated the AQP3-induced insensitivity to sorafenib observed in hypoxic cells transfected with Lv-AQP3. Combined with LY294002-treated cells, hypoxic cells transfected with Lv-AQP3RNAi were more sensitive to sorafenib.

Conclusion

The study results show that AQP3 is a potential therapeutic target for improving the sensitivity of hypoxic HCC cells to sorafenib.

Comparative Efficacy of Cabozantinib and Regorafenib for Advanced Hepatocellular Carcinoma

Background

No trials have compared cabozantinib and regorafenib for the second-line treatment of advanced hepatocellular carcinoma (HCC).

Objectives

Conduct a matching-adjusted indirect comparison (MAIC) of the efficacy and safety of second-line cabozantinib and regorafenib in patients with advanced HCC and disease progression after prior sorafenib.

Methods

The CELESTIAL and RESORCE trials were used for indirect comparison of second-line cabozantinib and regorafenib in advanced HCC. Population-level data were available for RESORCE, individual patient data (IPD) for CELESTIAL. To align with RESORCE, the CELESTIAL population was limited to patients who received first-line sorafenib only. To minimize potential effect-modifying population differences, the CELESTIAL IPD were weighted to balance the distribution of clinically relevant baseline characteristics with those of RESORCE. Overall survival (OS) and progression-free survival (PFS) were evaluated for the matching-adjusted second-line CELESTIAL population and compared with those for RESORCE using weighted Kaplan-Meier curves and parametric modeling. Rates of grade 3/4 treatment-emergent adverse events (TEAEs) affecting > 5% of patients in any study arm were compared.

Results

In the matching-adjusted second-line populations (CELESTIAL, effective sample size = 266; RESORCE, n = 573), median (95% confidence interval) OS was similar for cabozantinib and regorafenib (11.4 [8.9–17.0] versus 10.6 [9.1–12.1] months; p = 0.3474, log-rank test). Median PFS was longer for cabozantinib than regorafenib (5.6 [4.9–7.3] versus 3.1 [2.8–4.2] months; p = 0.0005, log-rank test). There was a trend for lower rates of some grade 3/4 TEAEs with regorafenib than with cabozantinib, which may reflect the exclusion of sorafenib-intolerant patients from RESORCE but not from CELESTIAL, a difference that the MAIC methods could not remove. Only diarrhea rates were statistically significantly lower for regorafenib (p  ≤ 0.001).

Conclusions

Cabozantinib may achieve similar OS and prolonged PFS compared with regorafenib in patients with progressive advanced HCC after prior sorafenib.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01378-y) contains supplementary material, which is available to authorized users.

Cabozantinib and regorafenib are treatments approved for some patients with advanced hepatocellular carcinoma (HCC), a type of liver cancer, after disease progression despite prior sorafenib treatment. Cabozantinib, regorafenib and sorafenib are tyrosine kinase inhibitors (TKIs), meaning that they slow cancer progression by targeting specific ways that tumors grow. Cabozantinib and regorafenib offer benefits to patients compared with placebo (i.e., no treatment) for those who have progressed despite sorafenib treatment. No clinical studies have compared cabozantinib and regorafenib directly. This study compared the efficacy and safety of cabozantinib and regorafenib using data from trials of each drug versus placebo: CELESTIAL for cabozantinib and RESORCE for regorafenib. These two trials were similar—both involved patients with progressive advanced HCC who had received previous cancer treatment. There were some important differences, but these were minimized using statistical methods (matching and adjustments/“weighting”) allowing outcomes to be meaningfully compared. One difference that could not be removed by the statistical methods was that patients who were intolerant to prior sorafenib were excluded from RESORCE but were eligible for the CELESTIAL trial. In the otherwise matched populations, treatment with cabozantinib was associated with similar overall survival and significantly longer progression-free survival than regorafenib. Rates of diarrhea were significantly lower for regorafenib than cabozantinib, suggesting that regorafenib may be better tolerated, but this may reflect the exclusion of sorafenib-intolerant patients from RESORCE. These findings cannot replace a head-to-head study, but may help in guiding decision-making between cabozantinib and regorafenib in patients with progressive advanced HCC after soraftenib treatment.

Infiltrative non-mass-like hepatocellular carcinoma initially presenting with isolated malignant portal vein thrombosis: A case report and review of the literature

Hepatocellular carcinoma (HCC) shows a rising incidence and mortality rates worldwide. HCC is divided into several distinct subtypes, both morphologically and histopathologically. Among these subtypes, infiltrative HCC may be the most challenging subtype to diagnose, given its characteristic myriad of tumor nodules blended with normal hepatocytes without a distinct mass-like lesion. Herein, we report an unusual case of an infiltrative HCC initially presenting with isolated malignant portal vein thrombosis and provide a brief review of the literature regarding the infiltrative HCC subtype. Additionally, we demonstrate how sonoelastography could aid in detecting the appropriate biopsy area in the infiltrative HCC subtype. To our knowledge, there have not been previously reported cases describing the use of sonoelastography in the evaluation of the appropriate area for the targeted liver biopsy.

AR420626, a selective agonist of GPR41/FFA3, suppresses growth of hepatocellular carcinoma cells by inducing apoptosis via HDAC inhibition

Background

Hepatocellular carcinoma (HCC) is a major cause of cancer death worldwide and establishment of new chemotherapies for HCC is urgently needed. GPR41 [free fatty acid receptor 3 (FFA3)] is a G protein-coupled receptor for short chain fatty acids, including acetate, propionate, and butyrate. In our previous study, we showed that propionate enhances the cytotoxic effect of cisplatin in HCC cells and that this mechanism is dependent on inhibition of histone deacetylases (HDACs) via GPR41/FFA3. However, the antitumor action of GPR41/FFA3 has not been elucidated.

Methods

In this study, we examined AR420626 as a GPR41-selective agonist in HepG2 and HLE cells. Nude mice were used for HepG2 xenograft studies. The apoptotic effect of AR420626 was evaluated using flow cytometry analysis. Expression of apoptosis-related proteins and HDACs was evaluated by Western immunoblot. Gene silencing of HDAC 3/5/7 and GPR41 was performed using small interfering RNA. Expression of TNF-α mRNA was evaluated by TaqMan real-time polymerase chain reaction.

Results

We found that AR420626, a selective GPR41/FFA3 agonist, suppressed growth of HepG2 xenografts and inhibited proliferation of HCC cells by inducing apoptosis. AR420626 induced proteasome activation through mTOR phosphorylation, which reduced HDAC proteins, and then increased expression of TNF-α.

Conclusion

AR420626, a selective GPR41/FFA3 agonist, may be a candidate as a therapeutic agent for HCC.

Identification and validation of potential key long noncoding RNAs in sorafenib-resistant hepatocellular carcinoma cells

As the first-line treatment, sorafenib has been used for advanced hepatocellular carcinoma (HCC), but the chemoresistance commonly restricts to the clinical efficiency. In this study, we intend to investigate the genome-wide expression pattern of long noncoding RNAs (lncRNAs) in sorafenib-resistant HCC. Herein, we identified thousands of differentially expressed lncRNAs in sorafenib-resistant HCC cells by high-throughput sequencing compared to the parental. Besides, based on GO (Gene Ontology) term enrichment analysis, these differentially expressed lncRNAs are mainly related to binding and catalytic activity and biological regulation of metabolic processes in both the sorafenib-resistant Huh7 cells (Huh7-S) and sorafenib-resistant HepG2 cells (HepG2-S) compared to the parental cells. Moreover, when analyzed by KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway, the differentially expressed genes were significantly related to the tight junction. Among them, the expression of TCONS_00284048 and TCONS_00006019 was consistently up-regulated in sorafenib-resistant HCC cell lines, whereas when either was knocked down, the sensitivity of Huh7-S and HepG2-S cells to sorafenib was increased. Taken together, our data demonstrate that the lncRNA expression profile is significantly altered in sorafenib-resistant HCC cells as well as differentially expressed lncRNAs may play crucial functions on HCC sorafenib resistance and HCC progression.

ZHX2 restricts hepatocellular carcinoma by suppressing stem cell-like traits through KDM2A-mediated H3K36 demethylation

Background

Liver cancer stem cells (CSCs) are critical determinants of HCC relapse and therapeutic resistance, but the mechanisms underlying the maintenance of CSCs are poorly understood. We aimed to explore the role of tumor repressor Zinc-fingers and homeoboxes 2 (ZHX2) in liver CSCs.

Methods

CD133⁺ or EPCAM⁺ stem-like liver cancer cells were sorted from tumor tissues of HCC patients and HCC cell lines by flow cytometry. In addition, sorafenib-resistant cells, tumor-sphere forming cells and side population (SP) cells were respectively cultured and isolated as hepatic CSCs. The tumor-initiating and chemoresistance properties of ZHX2-overexpressing and ZHX2-knockdown cells were analyzed in vivo and in vitro. Microarray, luciferase reporter assay, chromatin immunoprecipitation (ChIP) and ChIP-on-chip analyses were performed to explore ZHX2 target genes. The expression of ZHX2 and its target gene were determined by quantitative RT-PCR, western blot, immunofluorescence and immunohistochemical staining in hepatoma cells and tumor and adjacent tissues from HCC patients.

Results

ZHX2 expression was significantly reduced in liver CSCs from different origins. ZHX2 deficiency led to enhanced liver tumor progression and expansion of CSC populations in vitro and in vivo. Re-expression of ZHX2 restricted capabilities of hepatic CSCs in supporting tumor initiation, self-renewal and sorafenib-resistance. Mechanically, ZHX2 suppressed liver CSCs via inhibiting KDM2A-mediated demethylation of histone H3 lysine 36 (H3K36) at the promoter regions of stemness-associated transcription factors, such as NANOG, SOX4 and OCT4. Moreover, patients with lower expression of ZHX2 and higher expression of KDM2A in tumor tissues showed significantly poorer survival.

Conclusion

ZHX2 counteracts stem cell traits through transcriptionally repressing KDM2A in HCC. Our data will aid in a better understanding of molecular mechanisms underlying HCC relapse and drug resistance.

Mebendazole augments sensitivity to sorafenib by targeting MAPK and BCL-2 signalling in n-nitrosodiethylamine-induced murine hepatocellular carcinoma

Sorafenib (SO) is a multi-kinase inhibitor that targets upstream signals in the MAPK pathway. Drug resistance and transient survival benefits are the main obstacles associated with SO treatment in Hepatocellular carcinoma (HCC) patients. Mebendazole (MBZ), an anthelmintic agent, has demonstrated activity against various cancer types. Therefore, we aimed to investigate the possible mechanisms of MBZ other than its anti-tubulin activity. MBZ (100 mg/kg/day, P.O.) was administered to N-nitrosodiethylamine-induced HCC mice as a monotherapeutic agent or in combination with SO. Our results revealed that MBZ decreased AFP levels, improved liver function and histology and increased survival in HCC mice, particularly when administered in combination with SO. MBZ also reduced hepatic inflammation and fibrogenesis as evidenced by reductions in TNF-α and TGF-β1 levels, respectively. Increased hepatic caspases-3 and -9 and decreased BCL-2 levels suggest induced-cell death. In addition, MBZ demonstrated anti-angiogenic, anti-metastatic, and anti-proliferative effects, as indicated by reduced VEGF levels, MMP-2:TIMP-1 ratios, and reduced cyclin D1 levels and Ki67 immunostaining, respectively. Our main finding was that MBZ targeted downstream signal of the MAPK pathway by inhibiting ERK1/2 phosphorylation. Targeting downstream MAPK signalling by MBZ and upstream signalling by SO is a novel approach to minimizing resistance and prolonging survival.

Huganpian, a traditional chinese medicine, inhibits liver cancer growth in vitro and in vivo by inducing autophagy and cell cycle arrest

Huganpian (HGP), a traditional chinese medicine composed of 6 herbs, possesses excellent therapeutic effects in clinical application. In this study, we aimed to elucidate the anti-tumor activity and the underlying mechanisms of HGP in liver cancer. The results of this study indicated that HGP effectively inhibited liver cancer growth in vitro and in vivo in a dose-dependent manner. Mechanistically, HGP exerted its anti-tumor effects by triggering autophagy with increased LC3Ⅱ and beclin1 levels and arrested the cell cycle on G0-G1 phase by downregulating the expressions of cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4) and cyclinE1 in vitro and in vivo. Meanwhile, HGP did not induce apoptosis significantly. Importantly, we also confirmed that there were fewer side effects of HGP on immune system. Taken together, our findings suggest for the first time that HGP may become a promising drug or adjuvant drug with a lower toxicity for liver cancer treatment in the future.

BEZ235 increases sorafenib inhibition of hepatocellular carcinoma cells by suppressing the PI3K/AKT/mTOR pathway

BACKGROUND

Sorafenib is an oral multi-kinase inhibitor that inhibits hepatocellular carcinoma (HCC) via the Ras/Raf/MAPK pathway. However, sorafenib loses effectiveness because most tumors acquire drug resistance over time. As the PI3K/AKT/mTOR signaling pathway is also activated abnormally in HCC, we evaluated the effect of sorafenib, in combination with a dual PI3K/mTOR inhibitor, BEZ235, on HCC cell proliferation and survival in vitro.

MATERIALS AND METHODS

Biological phenotypes were analysed in HCC cell lines, parental and sorafenib-resistant HepG2 cells (HepG2 and HepG2^R), treated with sorafenib or BEZ235, alone or in combination. HCC cellular proliferation and apoptosis were investigated, and perturbations of the Ras/Raf/MAPK and PI3K/AKT/mTOR signaling/survival pathways were evaluated by western blot analysis.

RESULTS

BEZ235 enhanced sorafenib inhibition of cellular proliferation, migration, and promotion of apoptosis in HepG2 and HepG2^R cells. The combined effects were associated with inhibition of phosphorylation of AKT, mTOR and S6K in the PI3K/AKT/mTOR pathway, whereas the combination of sorafenib and BEZ235 did not significantly alter the Ras/Raf/MAPK pathway compared with the effect of sorafenib alone.

CONCLUSION

Sorafenib/BEZ235 combination has potent anti-HCC cell activity. This anti-tumor activity is most likely multi-factorial, mainly involving PI3K down-regulation and AKT, mTOR and S6K dephosphorylation. Combined inhibition of PI3K/AKT/mTOR and Ras/Raf/MAPK pathways enhances sorafenib inhibition of HCC. The results of these in vitro studies suggest that trials of combined sorafenib and BEZ235 in the treatment of HCC should be considered.

Long noncoding RNA NEAT1 suppresses sorafenib sensitivity of hepatocellular carcinoma cells via regulating miR-335-c-Met

OBJECTIVES

To investigate the role of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating sorafenib (Sora) sensitivity of hepatocellular carcinoma (HCC) cells and possible signaling pathways.

METHODS

HCC cell lines and tumor tissue were quantified for NEAT1 expression by quantitative polymerase chain reaction (qPCR). Following shRNA (short hairpin RNA) knockdown of NEAT1, cell viability, apoptosis, and related protein expression were measured after drug treatment. The downstream target of NEAT1, including miR-335 and c-Met was studied using a combination of luciferase binding assay, gene knockdown/overexpression, western blot analysis, and cell viability/apoptosis assay. Cancer cells with NEAT1 knockdown were transplanted onto nude mice for in vivo tumorigenesis assay.

RESULTS

Silencing of NEAT1 in HCC cells facilitated Sora sensitivity by enhancing drug-induced apoptosis, and led to smaller tumor size on nude mice. Mechanistic study suggested that miR-335 was negatively regulated by NEAT1, and miR-335 further suppressed c-Met-Akt pathway, whose activation caused drug resistance of HCC cells. The knockdown of miR-335, or overexpression of c-Met, all remarkably abolished the proapoptotic effect of NEAT1 knockdown in HCC cells.

CONCLUSION

lncRNA NEAT1 mediates Sora resistance of HCC cells by suppressing miR-335 expression, and disinhibition on c-Met-Akt signaling pathway. Our results provide potency of NEAT1 as the biomarker for drug resistant HCC and possible treating targets.

Reversal of sorafenib resistance in hepatocellular carcinoma: epigenetically regulated disruption of 14-3-3η/hypoxia-inducible factor-1α

Sorafenib resistance is one of the main obstacles to the treatment of advanced/recurrent hepatocellular carcinoma (HCC). Here, sorafenib-resistant HCC cells and xenografts in nude mice were used as experimental models. A cohort of patients with advanced recurrent HCC who were receiving sorafenib therapy was used to assess the clinical significance of this therapy. Our data showed that 14-3-3η maintained sorafenib resistance in HCC. An analysis of the underlying molecular mechanisms revealed that 14-3-3η stabilizes hypoxia-inducible factor 1α (HIF-1α) through the inhibition of ubiquitin-dependent proteasome protein degradation, which leads to the maintenance of cancer stem cell (CSC) properties. We further found that microRNA-16 (miR-16) is a competent miRNA that reverses sorafenib resistance by targeting the 3'-UTR of 14-3-3η and thereby inhibits 14-3-3η/HIF-1α/CSC properties. In HCC patients, significant negative correlations were found between the expression of miR-16 and 14-3-3η, HIF-1α, or CSC properties. Further analysis showed that low miR-16 expression but high 14-3-3η expression can prognosticate sorafenib resistance and poor survival. Collectively, our present study indicated that miR-16/14-3-3η is involved in sorafenib resistance in HCC and that these two factors could be potential therapeutic targets and biomarkers for predicting the response to sorafenib treatment.

SIRT7 regulates hepatocellular carcinoma response to therapy by altering the p53-dependent cell death pathway

Background

Optimal therapeutic strategies for hepatocellular carcinoma (HCC) patients are still challenging due to the high recurrence rate after surgical resection and chemotherapy resistance. Growing evidence shows that genetic and epigenetic alterations are involved in HCC progression and resistance to therapy, however the molecular mechanisms underlying resistance to therapy have not been fully understood.

Methods

Expression of SIRT7 in 17 paired paraffin-embedded HCC tissues and adjacent nontumoral liver tissues was examined by immunohistochemistry and Western blot. The mRNA expression of SIRT7 in 20 paired frozen HCC tissues and adjacent nontumoral liver tissues was analyzed by quantitative RT-PCR. The biologic consequences of overexpression and knockdown of SIRT7 in HCC therapy sensitivity were studied in vitro and in vivo. Interaction between SIRT7 and p53 were studied in HCC cell lines.

Results

SIRT7 expression was frequently upregulated in clinical HCC samples, and its expression was highly associated with TACE-resistance and poor survival (P = 0.008.) Depletion of SIRT7 from multiple liver cancer cell lines significantly increased doxorubicin toxicity while overexpression of SIRT7 largely abolished doxorubicin induced apoptosis. At the molecular level, we observed that SIRT7 interacts with and induces deacetylation of p53 at lysines 320 and 373. Deacetylated p53 showed significantly less affinity for the NOXA promoter and its transcription. In mouse xenografts, SIRT7 suppression increased doxorubicin induced p53 activation, inhibited tumor growth and induced apoptosis.

Conclusion

The newly identified SIRT7-p53-NOXA axis partially illustrates the molecular mechanism of HCC resistance to therapy and represents a novel potential therapeutic target for HCC treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1246-4) contains supplementary material, which is available to authorized users.

Plumbagin inhibits proliferation and induces apoptosis of hepatocellular carcinoma by downregulating the expression of SIVA

Purpose: Plumbagin is thought to be a bioactive phytochemical drug and exerts an antitumor effect on various cancers. However, few studies focus on the antitumor activity of plumbagin on liver cancer. This study first investigated the antitumor activity of plumbagin on liver cancer and further investigated the molecular mechanism of its antitumor activity against hepatocellular carcinoma, both in vitro and in vivo.

Methods: The antiproliferative activity of plumbagin was evaluated through CCK-8, EdU, and colony forming test. The cell cycle and apoptosis were then analyzed by flow cytometer. Western blot was used to detect the expression of apoptosis related protein, SIVA, and mTOR pathway. RNA-seq was performed to determine the gene expression profiles and overexpressed or knocked down SIVA to validate its role in plumbagin’s antitumor activity. Regarding animal experiment, a xenograft model in BALB/c nude mice was built using LM3-Luci cells. Then bioluminescence imaging and further immunohistochemistry were performed to study the antitumor activity and the expression of SIVA and mTOR in the plumbagin-treated group.

Results: Plumbagin can inhibit proliferation and induce apoptosis of liver cancer cells in vitro. Further experiment demonstrated that plumbagin could inhibit the expression of SIVA and subsequently downregulate the mTOR signaling pathway, and upregulating the expression of SIVA will alleviate the antitumor activity of plumbagin on liver cancer, which confirmed the important role of the SIVA/mTOR signaling pathway in the antitumor activity of plumbagin. In vivo bioluminescence imaging showed a decreased signal in the plumbagin-treated group, and further immunohistochemistry demonstrated that plumbagin could inhibit the SIVA/mTOR signaling pathway in tumor tissues.

Conclusion: Our promising results showed that plumbagin could inhibit proliferation and induce apoptosis of hepatic cancer through inhibiting the SIVA/mTOR signaling pathway for the first time, which indicated that plumbagin might be a good candidate against liver cancer.

EGFR and c-MET Cooperate to Enhance Resistance to PARP Inhibitors in Hepatocellular Carcinoma

PARP1 inhibitors (PARPi) are currently used in the clinic for the treatment of ovarian and breast cancers, yet their therapeutic efficacy against hepatocellular carcinoma (HCC) has been disappointing. To ensure therapeutic efficacy of PARPi against HCC, a disease often diagnosed at intermediate to advanced stages with no effective treatment options, it is critical to identify not only biomarkers to predict PARPi resistance but also rational treatments to overcome this. Here, we report that a heterodimer of EGFR and MET interacts with and phosphorylates Y907 of PARP1 in the nucleus, which contributes to PARPi resistance. Inhibition of both EGFR and MET sensitized HCC cells to PARPi, and both EGFR and MET are known to be overexpressed in HCC. This report provides an explanation for the poor efficacy of PARPi against HCC and suggests combinatorial treatment consisting of EGFR, MET, and PARP inhibitors may be an effective therapeutic strategy in HCC. SIGNIFICANCE: Regulation of PARP by the c-MET and EGFR heterodimer suggests a potentially effective combination therapy to sensitize HCC to PARPi.

Effects of a single transient transfection of Ten-eleven translocation 1 catalytic domain on hepatocellular carcinoma

Tumor suppressor genes (TSGs), including Ten-eleven translocation 1 (TET1), are hypermethylated in hepatocellular carcinoma (HCC). TET1 catalytic domain (TET1-CD) induces genome-wide DNA demethylation to activate TSGs, but so far, anticancer effects of TET1-CD are unclear. Here we showed that after HCC cells were transiently transfected with TET1-CD, the methylation levels of TSGs, namely APC, p16, RASSF1A, SOCS1 and TET1, were distinctly reduced, and their mRNA levels were significantly increased and HCC cells proliferation, migration and invasion were suppressed, but the methylation and mRNA levels of oncogenes, namely C-myc, Bmi1, EMS1, Kpna2 and c-fos, were not significantly change. Strikingly, HCC subcutaneous xenografts in nude mice remained to be significantly repressed even 54 days after transient transfection of TET1-CD. So, transient transfection of TET1-CD may be a great advance in HCC treatment due to its activation of multiple TSGs and persistent anticancer effects.

IL-2 augments the sorafenib-induced apoptosis in liver cancer by promoting mitochondrial fission and activating the JNK/TAZ pathway

Background

Sorafenib is the standard targeted drug used to treat hepatocellular carcinoma (HCC), but the therapeutic response between individuals varies markedly. Recently, cytokine-based immunotherapy has been a topic of intense discussion in the fight against cancer. The aim of this study was to explore whether cytokine IL-2 could augment the anti-tumour effects of sorafenib on HCC.

Methods

HepG2 and Huh7 cells were co-treated with sorafenib and IL-2 in vitro, and cellular viability and death were analysed through the MTT assay, TUNEL staining, LDH release assay, and western blotting. Mitochondrial function was measured via ELISA, immunofluorescence, and western blotting. Pathway blockers were used to establish the role of the JNK-TAZ pathways in regulating cancer cell phenotypes.

Results

Our data demonstrated that sorafenib treatment increased the HCC apoptotic rate, repressed cell proliferation, and inhibited migratory responses, and these effects were enhanced by IL-2 supplementation. Mechanistically, the combination of IL-2 and sorafenib interrupted mitochondrial energy metabolism by downregulating mitochondrial respiratory proteins. In addition, IL-2 and sorafenib co-treatment promoted mitochondrial dysfunction, as evidenced by the decreased mitochondrial potential, elevated mitochondrial ROS production, increased leakage of mitochondrial pro-apoptotic factors, and activation of the mitochondrial death pathway. A molecular investigation revealed that mitochondrial fission was required for the IL-2/sorafenib-mediated mitochondrial dysfunction. Mitochondrial fission was triggered by sorafenib and was largely amplified by IL-2 supplementation. Finally, we found that IL-2/sorafenib regulated mitochondrial fission via the JNK-TAZ pathways; blockade of the JNK-TAZ pathways abrogated the inhibitory effects of L-2/sorafenib on cancer survival, growth and mobility.

Conclusions

Altogether, these data strongly suggest that additional supplementation with IL-2 enhances the anti-tumour activity of sorafenib by promoting the JNK-TAZ-mitochondrial fission axis. This finding will pave the way for new treatment modalities to control HCC progression by optimizing sorafenib-based therapy.

Inhibiting TrxR suppresses liver cancer by inducing apoptosis and eliciting potent antitumor immunity

Liver cancer is one of the most common malignant tumors worldwide. Thioredoxin reductase (TrxR) is highly expressed in liver cancer cells. The present study aimed to investigate the effect of inhibiting TrxR on liver cancer and to better understand the underlying molecular and immuno-logical mechanisms associated with inhibition. It was demonstrated that targeting TrxR inhibited the growth and induced apoptosis of liver cancer cells, which was accompanied by activation of the mitogen associated protein kinase pathway. This inhibition was dependent on the production of reactive oxygen species (ROS). Blockage of ROS production reversed TrxR inhibitor‑induced antitumor effects. Blocking the Trx/TrxR system activated the mammalian target of rapamycin pathway and inhibited autophagy, which occurred in a ROS‑independent manner. TrxR inhibition led to lesions in the mitochondrial membrane, indicated by alterations in membrane potential. Mouse xenograft experiments were highly consistent with in vitro studies. Most importantly, blocking the Trx/TrxR system improved the tumor immune microenvironment. Together, these data demonstrated that TrxR is a potential target for liver cancer therapy, which could inhibit hepatocarcinogenesis and progression, and improve the antitumor immune response.

Pickering-Emulsion for Liver Trans-Arterial Chemo-Embolization with Oxaliplatin

PURPOSE

Biodegradable polylactic-co-glycolic acid (PLGA) nanoparticles can adsorb at the water/oil interface to stabilize the emulsion (forming Pickering-emulsion). The purpose of this study was to compare the release profiles of oxaliplatin from Pickering-emulsion and Lipiodol-emulsion.

MATERIALS/METHODS

Pickering-emulsions and Lipiodol-emulsions were both formulated with oxaliplatin (5 mg/mL) and Lipiodol (water/oil ratio: 1/3). For Pickering-emulsion only, PLGA nanoparticles (15 mg/mL) were dissolved into oxaliplatin before formulation. In vitro release of oxaliplatin from both emulsions was evaluated. Then, oxaliplatin was selectively injected into left hepatic arteries of 18 rabbits bearing VX2 liver tumors using either 0.5 mL Pickering-emulsion (n = 10) or 0.5 mL Lipiodol-emulsion (n = 8). In each group, half of the rabbits were killed at 1 h and half at 24 h. Mass spectrometry was used to quantify drug pharmacokinetics in blood and resulting tissue (tumors, right, and left livers) oxaliplatin concentrations.

RESULTS

Pickering-emulsion demonstrated a slow oxaliplatin release compared to Lipiodol-emulsion (1.5 ± 0.2 vs. 12.0 ± 6% at 1 h and 15.8 ± 3.0 vs. 85.3 ± 3.3% at 24 h) during in vitro comparison studies. For animal model studies, the plasmatic peak (C_max) and the area under the curve (AUC) were significantly lower with Pickering-emulsion compared to Lipiodol-emulsion (C_max = 0.49 ± 0.14 vs. 1.08 ± 0.41 ng/mL, p = 0.01 and AUC = 19.8 ± 5.9 vs. 31.8 ± 14.9, p = 0.03). This resulted in significantly lower oxaliplatin concentrations in tissues at 1 h with Pickering-emulsion but higher ratio between tumor and left liver at 24 h (43.4 vs. 14.5, p = 0.04).

CONCLUSION

Slow release of oxaliplatin from Pickering-emulsion results in a significant decrease in systemic drug exposure and higher ratio between tumor and left liver oxaliplatin concentration at 24 h.

Systemic treatments for hepatocellular carcinoma: challenges and future perspectives

Sorafenib has been the only approved systemic treatment of hepatocellular carcinoma (HCC) for almost a decade. Recently, two new drugs showed positive results in two Phase III studies. The RESORCE trial identified regorafenib as a valid second-line treatment for patients progressing to sorafenib, the REFLECT trial showed that lenvatinib is noninferior to sorafenib as front-line treatment. Following these trials, the therapeutic scenario will be dominated by anti-VEGFR drugs, with three different molecules showing a proven anticancer activity. Some open problems still remain and different immunotherapy trials are underway, following promising preliminary results. In this review we analyze: the most recent advancements about patients treated with sorafenib; the results of RESORCE and REFLECT trials; and the ongoing Phase III clinical trials. Finally, we discuss how they could address the current problems and possibly reshape the future of the systemic treatments for HCC.