Overexpression of c-Jun contributes to sorafenib resistance in human hepatoma cell lines

Survivin (BIRC5): Implications in cancer therapy

Inhibitors of Apoptosis proteins (IAPs) were discovered through experiments aimed at rescuing apoptosis in insects. Classically associated with the inhibition of apoptosis, the IAP member Survivin also regulates cell cycle progression and is an essential component of the Chromosomal Passenger Complex (CPC), responsible for chromosomal segregation. Although undetectable in most adult tissues, Survivin is expressed in Adult Stem Cells (ASCs) and plays a crucial role in their maintenance. Survivin is overexpressed in most cancers, contributing to their clonal expansion. As a result, it has been proposed as a possible anticancer target for nearly two decades. In this discussion, we will explore the rationale behind Survivin as a therapeutic target, focusing on common cancer types such as carcinomas, sarcomas, and leukemias. We will delve into the modulation of Survivin by cancer pro-survival cell signaling, the association between SNPs and tumorigenesis, and its regulation by miRNAs. Finally, we will compare cell growth, clonogenic capacity, and apoptosis, along with different strategies for Survivin inhibition, including gene expression and protein activity modulation.

Osteopontin regulates the growth and invasion of liver cancer cells via DTL

Osteopontin (OPN), a secreted phosphoglycoprotein, has important roles in tumor growth, invasion and metastasis in numerous types of cancers. Denticleless E3 ubiquitin protein ligase homolog (DTL), one of the CUL4-DDB1-associated factors (DCAFs), has also been associated with the invasion and metastasis of cancer cells. In the present study, OPN was found to induce DTL expression in liver cancer cells, and the results obtained using luciferase activity assays demonstrated that OPN could transcriptionally activate DTL expression in liver cancer cells. Furthermore, the results of the present study demonstrated that OPN could increase the expression of DTL via PI3K/AKT signaling. In conclusion, the present study demonstrated that OPN, as an extracellular matrix protein, is able to promote the growth and invasion of liver cancer cells through stimulation of the expression of DTL via the PI3K/AKT signaling pathway.

c-Jun-mediated JMJD6 restoration enhances resistance of liver cancer to radiotherapy through the IL-4-activated ERK pathway

Radiotherapy is widely used in the treatment of liver cancer, but the efficacy can be limited by radioresistance. In this study, we attempt to delineate the possible molecular mechanism of c-Jun-regulated Jumonji domain-containing protein 6/interleukin 4/extracellular signal-regulated kinase (JMJD6/IL-4/ERK) axis in radioresistance of liver cancer. The expression of c-Jun was quantified in liver cancer tissues and cell lines, and the results indicated that c-Jun was upregulated in liver cancer tissues and cells. We further illustrated the role of c-Jun following gain- and loss-of-function strategies in malignant phenotypes of liver cancer cells. It was established that c-Jun elevated JMJD6 expression and augmented the malignancy and aggressiveness of liver cancer cells. The in vivo effects of c-Jun on radioresistance in liver cancer were validated in nude mice, in response to IL-4 knockdown or the ERK pathway inhibitor, PD98059. In the presence of JMJD6 upregulation, the expression of IL-4 was elevated in mice with liver cancer, which enhanced the radiation resistance. Moreover, knockdown of IL-4 inactivated the ERK pathway, thereby reversing the radiation resistance caused by overexpressed JMJD6 in tumor-bearing mice. Taken together, c-Jun augments the radiation resistance in liver cancer by activating the ERK pathway through JMJD6-upregulated IL-4 transcription.

FBXW7 attenuates tumor drug resistance and enhances the efficacy of immunotherapy

FBXW7 (F-box and WD repeat domain containing 7) is a critical subunit of the Skp1-Cullin1-F-box protein (SCF), acting as an E3 ubiquitin ligase by ubiquitinating targeted protein. Through degradation of its substrates, FBXW7 plays a pivotal role in drug resistance in tumor cells and shows the potential to rescue the sensitivity of cancer cells to drug treatment. This explains why patients with higher FBXW7 levels exhibit higher survival times and more favorable prognosis. Furthermore, FBXW7 has been demonstrated to enhance the efficacy of immunotherapy by targeting the degradation of specific proteins, as compared to the inactivated form of FBXW7. Additionally, other F-box proteins have also shown the ability to conquer drug resistance in certain cancers. Overall, this review aims to explore the function of FBXW7 and its specific effects on drug resistance in cancer cells.

HBV Enhances Sorafenib Resistance in Hepatocellular Carcinoma by Reducing Ferroptosis via SRSF2-Mediated Abnormal PCLAF Splicing

Hepatocellular carcinoma (HCC) is one of the most lethal human cancers. Hepatitis B virus (HBV) infection accounts for nearly 50% of HCC cases. Recent studies indicate that HBV infection induces resistance to sorafenib, the first-line systemic treatment for advanced HCC for more than a decade, from 2007 to 2020. Our previous research shows that variant 1 (tv1) of proliferating cell nuclear antigen clamp-associated factor (PCLAF), overexpressed in HCC, protects against doxorubicin-induced apoptosis. However, there are no reports on the relevance of PCLAF in sorafenib resistance in HBV-related HCC. In this article, we found that PCLAF levels were higher in HBV-related HCC than in non-virus-related HCC using bioinformatics analysis. Immunohistochemistry (IHC) staining of clinical samples and the splicing reporter minigene assay using HCC cells revealed that PCLAF tv1 was elevated by HBV. Furthermore, HBV promoted the splicing of PCLAF tv1 by downregulating serine/arginine-rich splicing factor 2 (SRSF2), which hindered the inclusion of PCLAF exon 3 through a putative cis-element (116-123), "GATTCCTG". The CCK-8 assay showed that HBV decreased cell susceptibility to sorafenib through SRSF2/PCLAF tv1. HBV reduced ferroptosis by decreasing intracellular Fe²⁺ levels and activating GPX4 expression via the SRSF2/PCLAF tv1 axis, according to a mechanism study. Suppressed ferroptosis, on the other hand, contributed to HBV-mediated sorafenib resistance through SRSF2/PCLAF tv1. These data suggested that HBV regulated PCLAF abnormal alternative splicing by suppressing SRSF2. HBV caused sorafenib resistance by reducing ferroptosis via the SRSF2/PCLAF tv1 axis. As a result, the SRSF2/PCLAF tv1 axis may be a prospective molecular therapeutic target in HBV-related HCC, as well as a predictor of sorafenib resistance. The inhibition of the SRSF2/PCLAF tv1 axis may be crucial in the emergence of systemic chemotherapy resistance in HBV-associated HCC.

System Xc−/GSH/GPX4 axis: An important antioxidant system for the ferroptosis in drug-resistant solid tumor therapy

The activation of ferroptosis is a new effective way to treat drug-resistant solid tumors. Ferroptosis is an iron-mediated form of cell death caused by the accumulation of lipid peroxides. The intracellular imbalance between oxidant and antioxidant due to the abnormal expression of multiple redox active enzymes will promote the produce of reactive oxygen species (ROS). So far, a few pathways and regulators have been discovered to regulate ferroptosis. In particular, the cystine/glutamate antiporter (System Xc−), glutathione peroxidase 4 (GPX4) and glutathione (GSH) (System Xc−/GSH/GPX4 axis) plays a key role in preventing lipid peroxidation-mediated ferroptosis, because of which could be inhibited by blocking System Xc−/GSH/GPX4 axis. This review aims to present the current understanding of the mechanism of ferroptosis based on the System Xc−/GSH/GPX4 axis in the treatment of drug-resistant solid tumors.

Cell-cycle and apoptosis related and proteomics-based signaling pathways of human hepatoma Huh-7 cells treated by three currently used multi-RTK inhibitors

Sorafenib, lenvatinib and regorafenib, the multi-RTK inhibitors with potent anti-angiogenesis effects, are currently therapeutic drugs generally recommended for the patients with advanced hepatocellular carcinoma (HCC). To date, however, there have been no published studies on the mechanism underling differential effects of the three drugs on HCC cell proliferation, and the proteomic analysis in HCC cell lines treated by regorafenib or lenvatinib. The present study for the first time performed a direct comparison of the cell cycle arrest and apoptosis induction in the Huh-7 cells caused by sorafenib, regorafenib and lenvatinib at respective IC₅₀ using flow cytometry technique, as well as their pharmacological interventions for influencing whole cell proteomics using tandem mass tag-based peptide-labeling coupled with the nLC-HRMS technique. Sorafenib, regorafenib and lenvatinib at respective IC₅₀ drove the remaining surviving Huh-7 cells into a G₀/G₁ arrest, but lenvatinib and regorafenib were much more effective than sorafenib. Lenvatinib produced a much stronger induction of Huh-7 cells into early apoptosis than sorafenib and regorafenib, while necrotic cell proportion induced by regorafenib was 2.4 times as large as that by lenvatinib. The proteomic study revealed 419 proteins downregulated commonly by the three drugs at respective IC₅₀. KEGG pathway analysis of the downregulated proteins indicated the ranking of top six signaling pathways including the spliceosome, DNA replication, cell cycle, mRNA surveillance, P53 and nucleotide excision repair involved in 33 proteins, all of which were directly related to their pharmacological effects on cell cycle and cell apoptosis. Notably, lenvatinib and regorafenib downregulated the proteins of PCNA, Cyclin B1, BCL-xL, TSP1, BUD31, SF3A1 and Mad2 much more strongly than sorafenib. Moreover, most of the proteins in the P53 signaling pathway were downregulated with lenvatinib and regorafenib by more than 36% at least. In conclusion, lenvatinib and regorafenib have much stronger potency against Huh-7 cell proliferation than sorafenib because of their more potent effects on cell cycle arrest and apoptosis induction. The underling mechanism may be at least due to the 33 downregulated proteins centralizing the signal pathways of cell cycle, p53 and DNA synthesis based on the present proteomics study.

A Hypoxia-Sensitive Drug Delivery System Constructed by Nitroimidazole and its Application in the Treatment of Hepatocellular Carcinoma

Hypoxia is an important pathological phenomenon, and it can induce many tumor microenvironment changes, such as accumulations of intracellular lactic acid, decrease of tumor microenvironment pH value, and regulate a series of physiological and pathological processes such as adhesion, metastasis, and immune escape. Hypoxic tumor cells act as a key target for treating tumor. In this research, we designed and prepared PEG-nitroimidazole grafts, PEG-NI, and FA-PEG-NI. We first explored their physical and chemical properties to serve as a drug carrier. Then, the hypoxia-sensitive properties such as particle size changes and drug release were investigated. Finally, the tumor targeting ability was studied in vitro and in vivo, and anti-tumor capacity was determined. Both grafts showed excellent property as a nanodrug carrier and showed favorable drug encapsulation ability of sorafenib with the help of the hydrophobic chain of 6-(BOC-amino) hexyl bromide. The micelles responded to the hypoxic tumor environment with chemical and spatial structure changes leading to sensitive and fast drug release. With the modification of folic acid, FA-PEG-NI gained tumor targeting ability in vivo. FA-PEG-NI graft proved a potential targeting drug delivery system in the treatment of hypoxic hepatocellular carcinoma.

A multicentre study of the risk factors associated with recurrence of central serous chorioretinopathy

PURPOSE

To investigate potential clinical and multimodal imaging factors in central serous chorioretinopathy (CSC) recurrence.

METHODS

The study was performed at nine Japanese medical institutions for patients who had experienced an active CSC episode. Demographic data and medical history were reviewed retrospectively. Significant differences in chronic manifestation, leakage site, leakage point number, leakage intensity, choroidal hyperpermeability, central retinal thickness (CRT) and subfoveal choroidal thickness were analysed between the recurrence and non-recurrence groups.

RESULTS

In total, 538 eyes (538 patients) diagnosed with CSC (402 men, 136 women; mean age: 53.4 ± 11.9 years) were enrolled. Among them, 253 eyes (47.0%) developed ≥1 recurrence (follow-up: 15.9 ± 13.5 months, range 3-86 months). Univariate and multivariate analyses indicated that a history of corticosteroid use (odds ratio [OR], 5.52; 95% confidence interval [CI], 1.39-21.92; p = 0.015), bilateral disease (OR, 3.94; 95% CI, 1.47-10.6; p = 0.007), chronic manifestations (OR, 7.12; 95% CI, 2.93-17.28; p < 0.001), non-intense fluorescein leakage (OR, 3.34; 95% CI, 1.44-7.75; p = 0.005) and initial CRT (OR, 0.997; 95% CI, 0.993-0.999; p = 0.049) were significantly associated with CSC recurrence. Receiver operating characteristic curves were created, and the area under the curve for the multivariate logistic regression model of these five factors was 0.814.

CONCLUSION

Patients with CSC who received corticosteroids and had bilateral disease, chronic manifestation, non-intense fluorescein leakage on fluorescein angiography or a relatively thinner CRT should be closely monitored to identify whether they are at high risk of recurrence.

Construction of immune-related lncRNA signature to predict aggressiveness, immune landscape, and drug resistance of colon cancer

BACKGROUND

Colon cancer remains one of the most common malignancies across the world. Thus far, a biomarker, which can comprehensively predict the survival outcomes, clinical characteristics, and therapeutic sensitivity, is still lacking.

METHODS

We leveraged transcriptomic data of colon cancer from the existing datasets and constructed immune-related lncRNA (irlncRNA) pairs. After integrating with clinical survival data, we performed differential analysis and identified 11 irlncRNAs signature using Lasso regression analysis. We next plotted the 1-, 5-, and 10-year curve lines of receiver operating characteristics, calculated the areas under the curve, and recognized the optimal cutoff point. Then, we validated the pair-risk model in terms of the survival outcomes of the patients involved. Moreover, we tested the reliability of the model for predicting tumor aggressiveness and therapeutic susceptibility of colon cancer. Additionally, we reemployed the 11 of irlncRNAs involved in the pair-risk model to construct an expression-risk model to predict the prognostic outcomes of the patients involved.

RESULTS

We recognized a total of 377 differentially expressed irlncRNAs (DEirlcRNAs), including 28 low-expressed and 349 high-expressed irlncRNAs in colon cancer patients. After performing a univariant Cox analysis, we identified 115 risk irlncRNAs that were significantly correlated with survival outcomes of patients involved. By taking the overlap of the DEirlcRNAs and the risk irlncRNAs, we ultimately recognized 55 irlncRNAs as core irlncRNAs. Then, we established a Cox HR model (pair-risk model) as well as an expression HR model (exp-risk model) based on 11 of the 55 core irlncRNAs. We found that both of the two models significantly outperformed the commonly used clinical characteristics, including age, T, N, and M stages when predicting survival outcomes. Moreover, we validated the pair-risk model as a potential tool for studying the tumor microenvironment of colon cancer and drug susceptibility. Additionally, we noticed that combinational use of the pair-risk model and the exp-risk model yielded a more robust approach for predicting the survival outcomes of patients with colon cancer.

CONCLUSIONS

We recognized 11 irlncRNAs and created a pair-risk model and an exp-risk model, which have the potential to predict clinical characteristics of colon cancer, either solely or conjointly.

Sorafenib for hepatocellular carcinoma: potential molecular targets and resistance mechanisms

Hepatocellular carcinoma (HCC) is the most widespread typical therapy-resistant, unresectable type of malignant solid tumour with a high death rate constituting huge medical concern. Sorafenib is a small molecule oral multi-target kinase potent inhibitor that acts by suppressing/blocking the multiplication of the tumour cells, angiogenesis, and encouraging apoptosis of the tumour cells. Though, the precise mechanism of tumour cell death induction by sorafenib is yet under exploration. Furthermore, genetic heterogeneity plays a critical role in developing sorafenib resistance, which leads the way to identify the need for predictive biomarkers responsible for drug resistance. Therefore, it is essential to find out the fundamental resistance mechanisms to expand therapeutic plans. The authors summarize the molecular concepts of resistance, progression, potential molecular targets, HCC management therapies, and discussion on the advancements expected in the coming future, inclusive of biomarker-driven treatment strategies, which may provide the prospects to design innovative therapeutically targeted strategies for the HCC treatment and the clinical implementation of emerging targeted agents.

Sorafenib prevents the proliferation and induces the apoptosis of liver cancer cells by regulating autophagy and hypoxia-inducible factor-1

Sorafenib has been approved as a systemic drug for advanced liver cancer; however, the underlying mechanisms remain unclear. The present study aimed to investigate the effects of sorafenib on the proliferation, autophagy and apoptosis of HepG2 cells under hypoxia. Briefly, reverse transcription-quantitative PCR and western blotting was performed to quantify HIF-1, LC3II/I, mTOR and p70s6K expression levels. Cell proliferation was determined using the Cell Counting Kit-8 assay and the cell apoptosis rate was evaluated using flow cytometry. The results demonstrated that autophagy and apoptosis were induced by hypoxia, and that sorafenib further enhanced hypoxia-induced autophagy and apoptosis in HepG2 cells in a dose-dependent manner. Furthermore, the mechanism of sorafenib-mediated autophagy in liver cancer cell were investigated by using chloroquine (CQ). The results showed that CQ significantly inhibited autophagy by decreasing LC3II/LC3I ratio in HepG2 cells treated with sorafenib and/or hypoxia. By contrast, sorafenib could increase the expression of hypoxia-inducible factor-1 (HIF-1) and of the autophagy marker (LC3II/I) and decrease the expression of mammalian target of rapamycin and p70 ribosomal S6 kinase in HepG2 cells under normoxia and hypoxia conditions, suggesting that sorafenib could induce hypoxia and autophagy in liver cancer cells. In addition, sorafenib was demonstrated to prevent proliferation and induce apoptosis of HepG2 cells under normoxia and hypoxia. Sorafenib could also prevent the malignant behavior of HepG2 by inducing hypoxia and autophagy. In summary, the findings from the present study suggested that sorafenib may inhibit liver cancer progression by activating autophagy and HIF-1 signaling pathway.

Dual Targeting of Sorafenib-Resistant HCC-Derived Cancer Stem Cells

Sorafenib, an oral multi-tyrosine kinase inhibitor, has been the first-line therapy for the treatment of patients with advanced HCC, providing a survival benefit of only three months in approximately 30% of patients. Cancer stem cells (CSCs) are a rare tumour subpopulation with self-renewal and differentiation capabilities, and have been implicated in tumour growth, recurrence and drug resistance. The process of epithelial-to-mesenchymal transition (EMT) contributes to the generation and maintenance of the CSC population, resulting in immune evasion and therapy resistance in several cancers, including HCC. The aim of this study is to target the chemoresistant CSC population in HCC by assessing the effectiveness of a combination treatment approach with Sorafenib, an EMT inhibitor and an immune checkpoint inhibitor (ICI). A stem-cell-conditioned serum-free medium was utilised to enrich the CSC population from the human HCC cell lines Hep3B, PLC/PRF/5 and HepG2. The anchorage independent spheres were characterised for CSC features. The human HCC-derived spheres were assessed for EMT status and expression of immune checkpoint molecules. The effect of combination treatment with SB431542, an EMT inhibitor, and siRNA-mediated knockdown of programmed cell death protein ligand-1 (PD-L1) or CD73 along with Sorafenib on human HCC-derived CSCs was examined with cell viability and apoptosis assays. The three-dimensional spheres enriched from human HCC cell lines demonstrated CSC-like features. The human HCC-derived CSCs also exhibited the EMT phenotype along with the upregulation of immune checkpoint molecules. The combined treatment with SB431542 and siRNA-mediated PD-L1 or CD73 knockdown effectively enhanced the cytotoxicity of Sorafenib against the CSC population compared to Sorafenib alone, as evidenced by the reduced size and proliferation of spheres. Furthermore, the combination treatment of Sorafenib with SB431542 and PD-L1 or CD73 siRNA resulted in an increased proportion of an apoptotic population, as evidenced by flow cytometry analysis. In conclusion, the combined targeting of EMT and immune checkpoint molecules with Sorafenib can effectively target the CSC tumour subpopulation.

Fibrinogen-Like Protein 1 Modulates Sorafenib Resistance in Human Hepatocellular Carcinoma Cells

Despite liver cancer being the second-leading cause of cancer-related death worldwide, few systemic drugs have been approved. Sorafenib, the first FDA-approved systemic drug for unresectable hepatocellular carcinoma (HCC), is limited by resistance. However, the precise mechanisms underlying this phenomenon are unknown. Since fibrinogen-like 1 (FGL1) is involved in HCC progression and upregulated after anticancer therapy, we investigated its role in regulating sorafenib resistance in HCC. FGL1 expression was assessed in six HCC cell lines (HepG2, Huh7, Hep3B, SNU387, SNU449, and SNU475) using western blotting. Correlations between FGL1 expression and sorafenib resistance were examined by cell viability, colony formation, and flow cytometry assays. FGL1 was knocked-down to confirm its effects on sorafenib resistance. FGL1 expression was higher in HepG2, Huh7, and Hep3B cells than in SNU387, SNU449, and SNU475 cells; high FGL1-expressing HCC cells showed a lower IC₅₀ and higher sensitivity to sorafenib. In Huh7 and Hep3B cells, FGL1 knockdown significantly increased colony formation by 61% (p = 0.0013) and 99% (p = 0.0002), respectively, compared to that in controls and abolished sorafenib-induced suppression of colony formation, possibly by modulating ERK and autophagy signals. Our findings demonstrate that sorafenib resistance mediated by FGL1 in HCC cells, suggesting FGL1 as a potential sorafenib-resistance biomarker and target for HCC therapy.

Combined Inhibition of TGF-β1-Induced EMT and PD-L1 Silencing Re-Sensitizes Hepatocellular Carcinoma to Sorafenib Treatment

Hepatocellular carcinoma (HCC) is the most common type of primary hepatic malignancy. HCC is one of the leading causes of cancer deaths worldwide. The oral multi-tyrosine kinase inhibitor Sorafenib is the standard first-line therapy in patients with advanced unresectable HCC. Despite the significant survival benefit in HCC patients post treatment with Sorafenib, many patients had progressive disease as a result of acquiring drug resistance. Circumventing resistance to Sorafenib by exploring and targeting possible molecular mechanisms and pathways is an area of active investigation worldwide. Epithelial-to-mesenchymal transition (EMT) is a cellular process allowing epithelial cells to assume mesenchymal traits. HCC tumour cells undergo EMT to become immune evasive and develop resistance to Sorafenib treatment. Immune checkpoint molecules control immune escape in many tumours, including HCC. The aim of this study is to investigate whether combined inhibition of EMT and immune checkpoints can re-sensitise HCC to Sorafenib treatment. Post treatment with Sorafenib, HCC cells PLC/PRF/5 and Hep3B were monitored for induction of EMT and immune checkpoint molecules using quantitative reverse transcriptase (qRT)- PCR, western blot, immunofluorescence, and motility assays. The effect of combination treatment with SB431542, a specific inhibitor of the transforming growth factor (TGF)-β receptor kinase, and siRNA mediated knockdown of programmed cell death protein ligand-1 (PD-L1) on Sorafenib resistance was examined using a cell viability assay. We found that three days of Sorafenib treatment activated EMT with overexpression of TGF-β1 in both HCC cell lines. Following Sorafenib exposure, increase in the expression of PD-L1 and other immune checkpoints was observed. SB431542 blocked the TGF-β1-mediated EMT in HCC cells and also repressed PD-L1 expression. Likewise, knockdown of PD-L1 inhibited EMT. Moreover, the sensitivity of HCC cells to Sorafenib was enhanced by combining a blockade of EMT with SB431542 and knockdown of PD-L1 expression. Sorafenib-induced motility was attenuated with the combined treatment of SB431542 and PD-L1 knockdown. Our findings indicate that treatment with Sorafenib induces EMT and expression of immune checkpoint molecules, which contributes to Sorafenib resistance in HCC cells. Thus, the combination treatment strategy of inhibiting EMT and immune checkpoint molecules can re-sensitise HCC cells to Sorafenib.

Identification of a new TRAF6 inhibitor for the treatment of hepatocellular carcinoma

Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase that plays a crucial role in signal transduction. Previous studies have demonstrated that TRAF6 is overexpressed in hepatocellular carcinoma (HCC) and that TRAF6 knockdown dramatically attenuates tumor cell growth. Thus, TRAF6 may represent a potential therapeutic target for the treatment of HCC. Herein, we identified bis (4-hydroxy-3,5-dimethylphenyl) sulfone (TMBPS) as a novel inhibitor that can directly bind to and downregulate the level of TRAF6. In vitro experimental results showed that TMBPS arrests the cell cycle in the G2/M phase by inactivating the protein kinase B (AKT) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways and induces apoptosis by activating the p38/mitogen-activated protein kinase (MAPK) signaling pathway. In addition, TMBPS exhibited significant tumor growth inhibition in mouse xenograft models. In summary, our findings offer a proof-of-concept for the use of TMBPS as a novel chemotherapy drug for the prevention or treatment of HCC.

Role of Alpha-Fetoprotein in Hepatocellular Carcinoma Drug Resistance

Hepatocellular carcinoma (HCC) is a major type of primary liver cancer and a major cause of cancer-related deaths worldwide because of its high recurrence rate and poor prognosis. Surgical resection is currently the major treatment measure for patients in the early and middle stages of the disease. Because due to late diagnosis, most patients already miss the opportunity for surgery upon disease confirmation, conservative chemotherapy (drug treatment) remains an important method of comprehensive treatment for patients with middle- and late-stage liver cancer. However, multidrug resistance (MDR) in patients with HCC severely reduces the treatment effect and is an important obstacle to chemotherapeutic success. Alpha-fetoprotein (AFP) is an important biomarker for the diagnosis of HCC. The serum expression levels of AFP in many patients with HCC are increased, and a persistently increased AFP level is a risk factor for HCC progression. Many studies have indicated that AFP functions as an immune suppressor, and AFP can promote malignant transformation during HCC development and might be involved in the process of MDR in patients with liver cancer. This review describes drug resistance mechanisms during HCC drug treatment and reviews the relationship between the mechanism of AFP in HCC development and progression and HCC drug resistance.

3D human liver organoids: An in vitro platform to investigate HBV infection, replication and liver tumorigenesis

Hepatitis B Virus (HBV) infection is a leading cause of chronic liver cirrhosis and hepatocellular carcinoma (HCC) with an estimated 400 million people infected worldwide. The precise molecular mechanisms underlying HBV replication and tumorigenesis have remained largely uncharacterized due to the lack of a primary cell model to study HBV, a virus that exhibits stringent host species and cell-type specificity. Organoid technology has recently emerged as a powerful tool to investigate human diseases in a primary 3D cell-culture system that maintains the organisation and functionality of the tissue of origin. In this review, we describe the utilisation of human liver organoid platforms to study HBV. We first present the different categories of liver organoids and their demonstrated ability to support the complete HBV replication cycle. We then discuss the potential applications of liver organoids in investigating HBV infection and replication, related tumorigenesis and novel HBV-directed therapies. Liver organoids can be genetically modified, patient-derived, expanded and biobanked, thereby serving as a clinically-relevant, human, primary cell-derived platform to investigate HBV. Finally, we provide insights into the future applications of this powerful technology in the context of HBV-infection and HCC.

The Effect of Alpha Mangostin on Epithelial-Mesenchymal Transition on Human Hepatocellular Carcinoma HepG2 Cells Surviving Sorafenib via TGF-β/Smad Pathways

Purpose: This study was intended to find out the impact of alpha mangostin administration on the epithelial-mesenchymal transition (EMT) markers and TGF-β/Smad pathways in hepatocellular carcinoma Hep-G2 cells surviving sorafenib.

Methods: Hepatocellular carcinoma HepG2 cells were treated with sorafenib 10 μM. Cells surviving sorafenib treatment (HepG2^surv) were then treated vehicle, sorafenib, alpha mangostin, or combination of sorafenib and alpha mangostin. Afterward, cells were observed for their morphology with an inverted microscope and counted for cell viability. The concentrations of transforming growth factor (TGF)-β1 in a culture medium were examined using ELISA. The mRNA expressions of TGF-β1, TGF-β1-receptor, Smad3, Smad7, E-cadherin, and vimentin were evaluated using quantitative reverse transcriptase–polymerase chain reaction. The protein level of E-cadherin was also determined using western blot analysis.

Results: Treatment of alpha mangostin and sorafenib caused a significant decrease in the viability of sorafenib-surviving HepG2 cells versus control (both groups with P <0.05). Our study found that alpha mangostin treatment increased the expressions of vimentin (P <0.001 versus control). In contrast, alpha mangostin treatment tends to decrease the expressions of Smad7 and E-cadherin (both with P >0.05). In line with our findings, the expressions of TGF-β1 and Smad3 are significantly upregulated after alpha mangostin administration (both with P <0.05) versus control.

Conclusion: Alpha mangostin reduced cell viability of sorafenib-surviving HepG2 cells; however, it also enhanced epithelial–mesenchymal transition markers by activating TGF-β/Smad pathways.

Modulating the Crosstalk between the Tumor and Its Microenvironment Using RNA Interference: A Treatment Strategy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with one of the highest mortality rates among solid cancers. It develops almost exclusively in the background of chronic liver inflammation, which can be caused by viral hepatitis, chronic alcohol consumption or an unhealthy diet. Chronic inflammation deregulates the innate and adaptive immune responses that contribute to the proliferation, survival and migration of tumor cells. The continuous communication between the tumor and its microenvironment components serves as the overriding force of the tumor against the body's defenses. The importance of this crosstalk between the tumor microenvironment and immune cells in the process of hepatocarcinogenesis has been shown, and therapeutic strategies modulating this communication have improved the outcomes of patients with liver cancer. To target this communication, an RNA interference (RNAi)-based approach can be used, an innovative and promising strategy that can disrupt the crosstalk at the transcriptomic level. Moreover, RNAi offers the advantage of specificity in comparison to the treatments currently used for HCC in clinics. In this review, we will provide the recent data pertaining to the modulation of a tumor and its microenvironment by using RNAi and its potential for therapeutic intervention in HCC.

The mechanisms of sorafenib resistance in hepatocellular carcinoma: theoretical basis and therapeutic aspects

Sorafenib is a multikinase inhibitor capable of facilitating apoptosis, mitigating angiogenesis and suppressing tumor cell proliferation. In late-stage hepatocellular carcinoma (HCC), sorafenib is currently an effective first-line therapy. Unfortunately, the development of drug resistance to sorafenib is becoming increasingly common. This study aims to identify factors contributing to resistance and ways to mitigate resistance. Recent studies have shown that epigenetics, transport processes, regulated cell death, and the tumor microenvironment are involved in the development of sorafenib resistance in HCC and subsequent HCC progression. This study summarizes discoveries achieved recently in terms of the principles of sorafenib resistance and outlines approaches suitable for improving therapeutic outcomes 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.

Diospyros kaki leaves inhibit HGF/Met signaling-mediated EMT and stemness features in hepatocellular carcinoma

Persimmon (Diospyros kaki L.f.) trees are widely cultivated for their edible fruits in Asia. D. kaki leaves are abundant in phytochemicals that have numerous medicinal properties. Hepatocyte growth factor (HGF) and its receptor Met lead to poor prognosis via the promotion of metastasis and chemoresistance in hepatocellular carcinoma (HCC). Therefore, inhibitors targeting the HGF/Met pathway are regarded as promising drugs against HCC. Here, we investigated the effects of D. kaki leaves on HGF-induced epithelial-to-mesenchymal transition (EMT) and stemness traits in HCC. The ethanol extract of D. kaki leaves (EEDK) markedly suppressed HGF-mediated cell migration and invasion through upregulation of CDH1 and downregulation of SNAI1, VIM, MMP1, MMP2, and MMP9. Moreover, EEDK increased the cytotoxicity of sorafenib, which was reduced by HGF, and decreased the expression of the stemness markers KRT19 and CD44. Additionally, we found a clear correlation between stemness and EMT markers in HCC patients. Importantly, EEDK reduced Met activity and attenuated HGF-mediated activation of JNK/c-Jun. Our findings provide new evidence that EEDK can ameliorate HCC with poor prognosis and aggressive phenotype by blocking HGF/Met signaling.

Molecular alterations associated with acquired resistance to BRAFV600E targeted therapy in melanoma cells

Selective inhibition of the mutant BRAF protein is a highly promising therapeutic approach for melanoma patients carrying the BRAF mutation. Despite the remarkable clinical response, most patients develop resistance and experience tumour regrowth. To clarify the molecular background of BRAF inhibitor resistance, we generated four drug-resistant melanoma cell lines from paired primary/metastatic cell lines using a vemurafenib analogue PLX4720. Three of the resistant cell lines showed decreased proliferation after drug withdrawal, but the proliferation of one cell line (WM278) increased notably. Furthermore, we observed opposite phenomena in which a 'drug holiday' could not only be beneficial but also contribute to tumour progression. Using genomic and proteomic approaches, we found significantly different alterations between the sensitive and resistant cell lines, some of which have not been reported previously. In addition to several other changes, copy number gains were observed in all resistant cell lines on 8q24.11-q24.12 and 8q21.2. Gene expression analysis showed that most genes upregulated in the resistant cell lines were associated with cell motility and angiogenesis. Increased expression of six proteins (ANGPLT4, EGFR, Endoglin, FGF2, SerpinE1 and VCAM-1) and decreased expression of two proteins (osteopontin and survivin) were observed consistently in all resistant cell lines. In summary, we identified new genomic alterations and characterized the protein expression patterns associated with the resistant phenotype. Although several proteins have been shown to be associated with BRAF resistance, our study is the first to describe the association of VCAM-1 and osteopontin with BRAF resistance.

Different Mechanisms of Action of Regorafenib and Lenvatinib on Toll-Like Receptor-Signaling Pathways in Human Hepatoma Cell Lines

Multiple kinase inhibitors are available for patients with advanced hepatocellular carcinoma (HCC). It is largely unknown whether regorafenib or lenvatinib modulates innate immunity including Toll-like receptor (TLR)-signaling pathways in HCC. We performed real-time RT-PCR to investigate 84 TLR-associated gene expression levels and compared these gene expression levels in each hepatoma cells treated with or without regorafenib or lenvatinib. In response to regorafenib, nine and 10 genes were upregulated in Huh7 and HepG2 cells, respectively, and only C-X-C motif chemokine ligand 10 was upregulated in both cell lines. A total of 14 and 12 genes were downregulated in Huh7 and HepG2 cells, respectively, and two genes (Fos proto-oncogene, AP-1 transcription factor subunit, and ubiquitin conjugating enzyme E2 N) were downregulated in both cell lines. In response to lenvatinib, four and 16 genes were upregulated in Huh7 and HepG2 cells, respectively, and two genes (interleukin 1 alpha and TLR4) were upregulated in both cells. Six and one genes were downregulated in Huh7 and HepG2, respectively, and no genes were downregulated in both cell lines. In summary, regorafenib and lenvatinib affect TLR signaling pathways in human hepatoma cell lines. Modulation of TLR signaling pathway may improve the treatment of HCC patients with refractory disease.

CCL22 signaling contributes to sorafenib resistance in hepatitis B virus-associated hepatocellular carcinoma

The HBV-initiated hepatocellular carcinoma (HCC) frequently develops from or accompanies long-term chronic hepatitis, inflammation, and cirrhosis, and has a poor prognosis. Sorafenib, an orally active multi-kinase inhibitor, currently the most common approved drug for first-line systemic treatment of advanced HCC, only improves overall survival of three months, suggesting the need for new therapeutic strategies. In this study, we identified that sorafenib selectively resisted in immune competent C57BL/6 mice but not nude mice. The chemokines CCL22 and CCL17 were upregulated by sorafenib, which elevated dramatically higher in HBV-associated HCC. Mechanically, sorafenib accelerates CCL22 expression via TNF-α-RIP1-NF-κB signaling pathway. Blocking CCL22 signaling with antagonist C-021 and sorafenib treated in combination can inhibit tumor growth and enhance the antitumor response, whereas no significant differences in tumor burden were observed in nude mice upon addition of C-021. These findings strongly suggest that CCL22 signaling pathway strongly contributes to sorafenib resistance in HBV-associated HCC, indicating a potential therapeutic strategy for immunological chemotherapy complementing first-line agents against HBV-associated HCC.

Fibroblast Growth Factor 9 is expressed by activated hepatic stellate cells and promotes progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is closely associated with liver fibrosis. Hepatic stellate cells (HSC) and cancer-associated myofibroblasts are key players in liver fibrogenesis and hepatocarcinogenesis. Overexpression of fibroblast growth factor (FGF) receptors contributes to HCC development and progression. This study aimed to elucidate the role of FGFs in the HSC-HCC crosstalk. Analysis of the expression of the fifteen paracrine FGF-members revealed that FGF9 was only expressed by HSC but not by HCC cells. Also in human HCC tissues, HSC/stromal myofibroblasts were identified as cellular source of FGF9. High expression levels of FGF9 significantly correlated with poor patient survival. Stimulation with recombinant FGF9 induced ERK- and JNK-activation combined with significantly enhanced proliferation, clonogenicity, and migration of HCC cells. Moreover, FGF9 significantly reduced the sensitivity of HCC cells against sorafenib. Protumorigenic effects of FGF9 on HCC cells were almost completely abrogated by the FGFR1/2/3 inhibitor BGJ398, while the selective FGFR4 inhibitor BLU9931 had no significant effect. In conclusion, these data indicate that stroma-derived FGF9 promotes tumorigenicity and sorafenib resistance of HCC cells and FGF9 overexpression correlates with poor prognosis in HCC patients. Herewith, FGF9 appears as potential prognostic marker and novel therapeutic target in HCC.

JNK activation and translocation to mitochondria mediates mitochondrial dysfunction and cell death induced by VDAC opening and sorafenib in hepatocarcinoma cells

The multikinase inhibitor sorafenib, and opening of voltage dependent anion channels (VDAC) by the erastin-like compound X1 promotes oxidative stress and mitochondrial dysfunction in hepatocarcinoma cells. Here, we hypothesized that X1 and sorafenib induce mitochondrial dysfunction by increasing reactive oxygen species (ROS) formation and activating c-Jun N-terminal kinases (JNKs), leading to translocation of activated JNK to mitochondria. Both X1 and sorafenib increased production of ROS and activated JNK. X1 and sorafenib caused a drop in mitochondrial membrane potential (ΔΨ), a readout of mitochondrial metabolism, after 60 min. Mitochondrial depolarization after X1 and sorafenib occurred in parallel with JNK activation, increased superoxide (O2•-) production, decreased basal and oligomycin sensitive respiration, and decreased maximal respiratory capacity. Increased production of O2•- after X1 or sorafenib was abrogated by JNK inhibition and antioxidants. S3QEL 2, a specific inhibitor of site IIIQo, at Complex III, prevented depolarization induced by X1. JNK inhibition by JNK inhibitors VIII and SP600125 also prevented mitochondrial depolarization. After X1, activated JNK translocated to mitochondria as assessed by proximity ligation assays. Tat-Sab KIM1, a peptide selectively preventing the binding of JNK to the outer mitochondrial membrane protein Sab, blocked the depolarization induced by X1 and sorafenib. X1 promoted cell death mostly by necroptosis that was partially prevented by JNK inhibition. These results indicate that JNK activation and translocation to mitochondria is a common mechanism of mitochondrial dysfunction induced by both VDAC opening and sorafenib.

Diclofenac Potentiates Sorafenib-Based Treatments of Hepatocellular Carcinoma by Enhancing Oxidative Stress

Sorafenib is the first developed systemic treatment for advanced forms of hepatocellular carcinoma, which constitutes the most frequent form of primary liver cancers and is a major global health burden. Although statistically significant, the positive effect of sorafenib on median survival remains modest, highlighting the need to develop novel therapeutic approaches. In this report, we introduce diclofenac, a nonsteroidal anti-inflammatory drug, as a potent catalyzer of sorafenib anticancer efficacy. Treatment of three different hepatocellular cancer cells (Huh-7, HepG2, and PLC-PRF-5) with sorafenib (5 µM, 24 h) and diclofenac (100 µM, 24 h) significantly increased cancer cell death compared to sorafenib or diclofenac alone. Anti-oxidant compounds, including N-acetyl-cysteine and ascorbic acid, reversed the deleterious effects of diclofenac/sorafenib co-therapy, suggesting that the generation of toxic levels of oxidative stress was responsible for cell death. Accordingly, whereas diclofenac increased production of mitochondrial oxygen reactive species, sorafenib decreased concentrations of glutathione. We further show that tumor burden was significantly diminished in mice bearing tumor xenografts following sorafenib/diclofenac co-therapy when compared to sorafenib or diclofenac alone. Taken together, these results highlight the anticancer benefits of sorafenib/diclofenac co-therapy in hepatocellular carcinoma. They further indicate that combining sorafenib with compounds that increase oxidative stress represents a valuable treatment strategy in hepatocellular carcinoma.

O-GlcNAcylated c-Jun antagonizes ferroptosis via inhibiting GSH synthesis in liver cancer

Ferroptosis is a metabolism-related cell death. Stimulating ferroptosis in liver cancer cells is a strategy to treat liver cancer. However, how to eradicate liver cancer cells through ferroptosis and the obstacles to inducing ferroptosis in liver cancer remain unclear. Here, we observed that erastin suppressed the malignant phenotypes of liver cancer cells by inhibiting O-GlcNAcylation of c-Jun and further inhibited protein expression, transcription activity and nuclear accumulation of c-Jun. Overexpression of c-Jun-WT with simultaneous PuGNAc treatment conversely inhibited erastin-induced ferroptosis, whereas overexpression of c-Jun-WT alone or overexpression of c-Jun-S73A (a non-O-GlcNAcylated form of c-Jun) with PuGNAc treatment did not exert a similar effect. GSH downregulation induced by erastin was restored by overexpression of c-Jun-WT with simultaneous PuGNAc treatment. In addition, overexpression of c-Jun-WT, but not its S73A mutant, induced PSAT1 and CBS transcription via directly binding to their promoter regions, suggesting that GSH synthesis is regulated by O-GlcNAcylated c-Jun. A positive correlation between c-Jun O-GlcNAcylation and GSH was observed in clinical samples. Collectively, O-GlcNAcylated c-Jun represents an obstructive factor to ferroptosis, and targeting O-GlcNAcylated c-Jun might be helpful for treating liver cancer.

The up-regulation of P62 levels is associated with resistance of sorafenib in hepatocarcinoma cells

BACKGROUND

Sorafenib is one of the most commonly used systemic therapies for hepatocellular carcinoma (HCC), but the acquired resistance towards sorafenib found in HCC patients usually led to failure of treatment and poor prognosis. Therefore, there is an urgent need to study the molecular mechanism caused by the acquired resistance. Previous studies demonstrated that P62 plays an important role in tumor cell resistance towards systemic therapies including chemotherapy and targeted therapy. However, the role of P62 in acquired resistance to sorafenib in HCC has not been clearly investigated.

MATERIALS AND METHODS

In this study we screened the most sensitive HCC cell lines towards sorafenib using CCK8. Then on this cell line, we analyzed the relationship between P62 expression level and the sensitivity towards sorafenib by western blot and CCK8. After knockdown and overexpression of P62 in HCC cells, cells were then treated with sorafenib. After that, we detect changes of sensitivity towards sorafenib. HCC samples were used to investigate the expression of P62 and their survival time.

RESULTS

Among four HCC cell lines in our lab, HepG2 cell line with the highest sensitivity to sorafenib was screened and selected. After treatment with sorafenib, the expression of P62 was significantly increased. In HCC cells, we found that significant up-regulation of P62 was correlated with the reduction of sorafenib sensitivity. In HCC samples, we found that the expression of P62 was associated with sorafenib resistance and a shorter survival time.

CONCLUSION

The up-regulation of P62 could reduce the sensitivity of HCC towards sorafenib. Thus, P62 could be therapeutic target to overcome sorafenib acquired resistance in the future.

JNK signaling in cancer cell survival

c-Jun N-terminal kinase (JNK) is involved in cancer cell apoptosis; however, emerging evidence indicates that this Janus signaling promotes cancer cell survival. JNK acts synergistically with NF-κB, JAK/STAT, and other signaling molecules to exert a survival function. JNK positively regulates autophagy to counteract apoptosis, and its effect on autophagy is related to the development of chemotherapeutic resistance. The prosurvival effect of JNK may involve an immune evasion mechanism mediated by transforming growth factor-β, toll-like receptors, interferon-γ, and autophagy, as well as compensatory JNK-dependent cell proliferation. The present review focuses on recent advances in understanding the prosurvival function of JNK and its role in tumor development and chemoresistance, including a comprehensive analysis of the molecular mechanisms underlying JNK-mediated cancer cell survival. There is a focus on the specific "Yin and Yang" functions of JNK1 and JNK2 in the regulation of cancer cell survival. We highlight recent advances in our knowledge of the roles of JNK in cancer cell survival, which may provide insight into the distinct functions of JNK in cancer and its potential for cancer therapy.

Small interfering RNA-mediated gene suppression as a therapeutic intervention in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the lethal and difficult-to-cure cancers worldwide. Owing to the late diagnosis and drug resistance of malignant hepatocytes, treatment of this cancer by conventional chemotherapy agents is challenging, and researchers are seeking new alternative treatment options to overcome therapy resistance in this neoplasm. RNA interference (RNAi) is a potent and specific approach in targeting gene expression and has emerged as a novel therapeutic tool for many diseases, including cancers. Small interfering RNA (siRNA) is a type of RNAi that is produced intracellularly from exogenous synthetic oligonucleotides and can selectively knock down target gene expression in a sequence-specific manner. Various factors play roles in the initiation and progression of HCC and provide multiple candidate targets for siRNA intervention. In addition, due to the liver's unique architecture and availability of some hepatic siRNA delivery methods, this organ has received much more attention as a target tissue for such oligonucleotide action. Recent advances in designing nanoparticle systems for the in vivo delivery of siRNAs have markedly enhanced the potency of siRNA-mediated gene silencing under clinical development for HCC therapy. The utility of siRNAs as anti-HCC agents is the subject of the current review. siRNA-based gene therapies could be one of the main feasible approaches for HCC therapy in the future.

Sestrin 2 confers primary resistance to sorafenib by simultaneously activating AKT and AMPK in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the malignancy derived from normal hepatocytes with increasing incidence and extremely poor prognosis worldwide. The only approved first‐line systematic treatment agent for HCC, sorafenib, is capable to effectively improve advanced HCC patients’ survival. However, it is gradually recognized that the therapeutic response to sorafenib could be drastically diminished after short‐term treatment, defined as primary resistance. The present study is aimed to explore the role of stress‐inducible protein Sestrin2 (SESN2), one of the most important sestrins family members, in sorafenib primary resistance. Herein, we initially found that SESN2 expression was significantly up‐regulated in both HCC cell lines and tissues compared to normal human hepatocytes and corresponding adjacent liver tissues, respectively. In addition, SESN2 expression was highly correlated with sorafenib IC₅₀ of HCC cell lines. Thereafter, we showed that sorafenib treatment resulted in an increase of SESN2 expression and the knockdown of SESN2 exacerbated sorafenib‐induced proliferation inhibition and cell apoptosis. Further mechanistic study uncovered that SESN2 deficiency impaired both AKT and AMPK phosphorylation and activation after sorafenib treatment. Moreover, the correlations between SESN2 expression and both phosphor‐AKT and phosphor‐AMPK expression were illustrated in HCC tissues. Taken together, our study demonstrates that SESN2 activates AKT and AMPK signaling as a novel mechanism to induce sorafenib primary resistance in HCC.

Discovery of VEGFR2 inhibitors by integrating naïve Bayesian classification, molecular docking and drug screening approaches

The high morbidity and mortality of cancer make it one of the leading causes of global death, thus it is an urgent need to develop effective drugs for cancer therapy.

New insights into sorafenib resistance in hepatocellular carcinoma: Responsible mechanisms and promising strategies

It is disappointing that only a few patients with hepatocellular carcinoma (HCC) obtain a significant survival benefit from the sorafenib treatment, which is currently regarded as a first-line chemotherapeutic therapy in patients with advanced HCC. Most patients are highly refractory to this therapy. Therefore, it is necessary to identify resistant factors and explore potential protocols that can be used to overcome the resistance or substitute sorafenib once the resistance is formed. In fact, a growing body of studies has been focusing on the resistance mechanisms or the method to overcome it. The limitation of sorafenib efficacy has been partially but not fully elucidated. Moreover, some protocols have shown encouraging outcomes but still need to be further verified in clinical trials. In this review, we summarize the recent findings on the potential mechanisms that contribute to sorafenib resistance and discuss strategies that can be used to improve the treatment outcome.