Chemical and genetic inhibition of STAT3 sensitizes hepatocellular carcinoma cells to sorafenib induced cell death

Novel STAT3 oligonucleotide compounds suppress tumor growth and overcome the acquired resistance to sorafenib in hepatocellular carcinoma

Signal transducer and activator of transcription 3 (STAT3) plays an important role in the occurrence and progression of tumors, leading to resistance and poor prognosis. Activation of STAT3 signaling is frequently detected in hepatocellular carcinoma (HCC), but potent and less toxic STAT3 inhibitors have not been discovered. Here, based on antisense technology, we designed a series of stabilized modified antisense oligonucleotides targeting STAT3 mRNA (STAT3 ASOs). Treatment with STAT3 ASOs decreased the STAT3 mRNA and protein levels in HCC cells. STAT3 ASOs significantly inhibited the proliferation, survival, migration, and invasion of cancer cells by specifically perturbing STAT3 signaling. Treatment with STAT3 ASOs decreased the tumor burden in an HCC xenograft model. Moreover, aberrant STAT3 signaling activation is one of multiple signaling pathways involved in sorafenib resistance in HCC. STAT3 ASOs effectively sensitized resistant HCC cell lines to sorafenib in vitro and improved the inhibitory potency of sorafenib in a resistant HCC xenograft model. The developed STAT3 ASOs enrich the tools capable of targeting STAT3 and modulating STAT3 activity, serve as a promising strategy for treating HCC and other STAT3-addicted tumors, and alleviate the acquired resistance to sorafenib in HCC patients. A series of novel STAT3 antisense oligonucleotide were designed and showed potent anti-cancer efficacy in hepatocellular carcinoma in vitro and in vivo by targeting STAT3 signaling. Moreover, the selected STAT3 ASOs enhance sorafenib sensitivity in resistant cell model and xenograft model.

Network pharmacology prediction and experiment validation of anti-liver cancer activity of Curcumae Rhizoma and Hedyotis diffusa Willd

Objective

This study aims to elucidate anti-liver cancer components and potential mechanisms of Curcumae Rhizoma and Hedyotis diffusa Willd (CR-HDW).

Methods

Effective components and targets of CR-HDW were identified from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. Liver cancer-related genes were collected from GeneCards, Gene-Disease Association (DisGeNET), and National Center for Biotechnology Information (NCBI). Protein-protein interaction networks, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were conducted to analyze the identified genes. Molecular docking was used to simulate binding of the active components and their target proteins. Cell activity assay, western blot, and senescence-associated β-galactosidase (SA-β-gal) experiments were conducted to validate core targets identified from molecular docking.

Results

Ten active compounds of CR-HDW were identified including quercetin, 3-epioleanic acid and hederagenin. The primary core proteins comprised Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Protein Kinase B(AKT1), etc. The pathways for Phosphoinositide 3-kinase (PI3K)/ AKT, cellular senescence, Fork head boxO (FOXO) were revealed as important for anti-cancer activity of CR-HDW. Molecular docking demonstrated strong binding between liver cancer target proteins and major active components of CR-HDW. In-vitro experiments confirmed that hederagenin and 3-epioleolic acid inhibited HuH-7 cell growth, reduced expression of PI3K, AKT, and mechanistic target of rapamycin (mTOR) proteins. Hederagenin also induced HuH-7 senescence.

Conclusions

In summary, The authors' results suggest that the CR-HDW component (Hederagenin, 3-epoxy-olanolic acid) can inhibit the proliferation of HuH-7 cells by decreasing PI3K, AKT, and mTOR. Hederagenin also induced HuH-7 senescence.

Butein inhibits oral squamous cell carcinoma growth via promoting MCL-1 ubiquitination

Oral squamous cell carcinoma (OSCC) is the most common malignant head and neck carcinoma type. Myeloid cell leukemia-1 (MCL-1), an anti-apoptotic BCL-1 protein, has been verified to be among the most highly upregulated pathologic proteins in human cancers linked to tumor relapse, poor prognosis and therapeutic resistance. Herein, therapeutic targeting MCL-1 is an attractive focus for cancer treatment. The present study found that butein, a potential phytochemical compound, exerted profound antitumor effects on OSCC cells. Butein treatment significantly inhibited cell viability, proliferation capacity and colony formation ability, and activated cell apoptotic process. Further potential mechanism investigation showed that promoting MCL-1 ubiquitination and degradation is the major reason for butein-mediated OSCC cell cytotoxicity. Our results uncovered that butein could facilitate E3 ligase FBW7 combined with MCL-1, which contributed to an increase in the ubiquitination of MCL-1 Ub-K48 and degradation. The results of both in vitro cell experiments and in vivo xenograft models imply a critical antitumor function of butein with the well-tolerated feature, and it might be an attractive and promising agent for OSCC treatment.

IL-22 signaling promotes sorafenib resistance in hepatocellular carcinoma via STAT3/CD155 signaling axis

Introduction

Sorafenib is currently the first-line treatment for patients with advanced hepatocellular carcinoma (HCC). Nevertheless, sorafenib resistance remains a huge challenge in the clinic. Therefore, it is urgent to elucidate the mechanisms underlying sorafenib resistance for developing novel treatment strategies for advanced HCC. In this study, we aimed to investigate the role and mechanisms of interleukin-22 (IL-22) in sorafenib resistance in HCC.

Methods

The in vitro experiments using HCC cell lines and in vivo studies with a nude mouse model were used. Calcium staining, chromatin immunoprecipitation, lactate dehydrogenase release and luciferase reporter assays were employed to explore the expression and roles of IL-22, STAT3 and CD155 in sorafenib resistance.

Results

Our clinical results demonstrated a significant correlation between elevated IL-22 expression and poor prognosis in HCC. Analysis of transcriptomic data from the phase-3 STORM-trial (BIOSTORM) suggested that STAT3 signaling activation and natural killer (NK) cell infiltration may associate sorafenib responses. STAT3 signaling could be activated by IL-22 administration in HCC cells, and then enhanced sorafenib resistance in HCC cells by promoting cell proliferation and reducing apoptosis in vitro and in vivo. Further, we found IL-22/STAT3 axis can transcriptionally upregulate CD155 expression in HCC cells, which could significantly reduce NK cell-mediated HCC cell lysis in a co-culture system.

Conclusions

Collectively, IL-22 could contribute to sorafenib resistance in HCC by activating STAT3/CD155 signaling axis to decrease the sensitivities of tumor cells to sorafenib-mediated direct cytotoxicity and NK cell-mediated lysis. These findings deepen the understanding of how sorafenib resistance develops in HCC in terms of IL-22/STAT3 signaling pathway, and provide potential targets to overcome sorafenib resistance in patients with advanced HCC.

Mechanisms and therapeutic prospect of the JAK-STAT signaling pathway in liver cancer

Liver cancer (LC) poses a significant global health challenge due to its high incidence and poor prognosis. Current systemic treatment options, such as surgery, chemotherapy, radiofrequency ablation, and immunotherapy, have shown limited effectiveness for advanced LC patients. Moreover, owing to the heterogeneous nature of LC, it is crucial to uncover more in-depth pathogenic mechanisms and develop effective treatments to address the limitations of the existing therapeutic modalities. Increasing evidence has revealed the crucial role of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway in the pathogenesis of LC. The specific mechanisms driving the JAK-STAT pathway activation in LC, participate in a variety of malignant biological processes, including cell differentiation, evasion, anti-apoptosis, immune escape, and treatment resistance. Both preclinical and clinical investigations on the JAK-STAT pathway inhibitors have exhibited potential in LC treatment, thereby opening up avenues for the development of more targeted therapeutic strategies for LC. In this study, we provide an overview of the JAK-STAT pathway, delving into the composition, activation, and dynamic interplay within the pathway. Additionally, we focus on the molecular mechanisms driving the aberrant activation of the JAK-STAT pathway in LC. Furthermore, we summarize the latest advancements in targeting the JAK-STAT pathway for LC treatment. The insights presented in this review aim to underscore the necessity of research into the JAK-STAT signaling pathway as a promising avenue for LC therapy.

Effect of traditional Chinese medicine in osteosarcoma: Cross-interference of signaling pathways and potential therapeutic targets

Osteosarcoma (OS) has a high recurrence rate, disability rate, mortality and metastasis, it brings great economic burden and psychological pressure to patients, and then seriously affects the quality of life of patients. At present, the treatment methods of OS mainly include radiotherapy, chemotherapy, surgical therapy and neoadjuvant chemotherapy combined with limb salvage surgery. These treatment methods can relieve the clinical symptoms of patients to a certain extent, and also effectively reduce the disability rate, mortality and recurrence rate of OS patients. However, because metastasis of tumor cells leads to new complications, and OS cells become resistant with prolonged drug intervention, which reduces the sensitivity of OS cells to drugs, these treatments still have some limitations. More and more studies have shown that traditional Chinese medicine (TCM) has the characteristics of "multiple targets and multiple pathways," and can play an important role in the development of OS through several key signaling pathways, including PI3K/AKT, Wnt/β-catenin, tyrosine kinase/transcription factor 3 (JAK/STAT3), Notch, transforming growth factor-β (TGF-β)/Smad, nuclear transcription factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), nuclear factor E2-related factor 2 (Nrf2), Hippo/YAP, OPG/RANK/RANKL, Hedgehog and so on. In this paper, the signaling pathways of cross-interference between active ingredients of TCM and OS were reviewed, and the development status of novel OS treatment was analyzed. The active ingredients in TCM can provide therapeutic benefits to patients by targeting the activity of signaling pathways. In addition, potential strategies for targeted therapy of OS by using ferroptosis were discussed. We hope to provide a unique insight for the in-depth research and clinical application of TCM in the fields of OS growth, metastasis and chemotherapy resistance by understanding the signaling crosstalk between active ingredients in TCM and OS.

Venetoclax Overcomes Sorafenib Resistance in Acute Myeloid Leukemia by Targeting BCL2

Sorafenib, a kinase inhibitor, has shown promising therapeutic efficacy in a subset of patients with acute myeloid leukemia (AML). However, despite its clinical effectiveness, sorafenib resistance is frequently observed in clinical settings, and the mechanisms underlying this resistance as well as effective strategies to overcome it remain unclear. We examined both single-cell and bulk transcription data in sorafenib-resistant and control AML patients and integrated a sorafenib resistance gene signature to predict the sensitivity of AML cells and the clinical outcomes of AML patients undergoing sorafenib therapy. In addition, our drug sensitivity analysis of scRNA-seq data using deconvolution methods showed that venetoclax was effective in targeting sorafenib-resistant AML cells. Mechanistically, sorafenib was found to activate the JAK-STAT3 pathway and upregulate BCL2 expression in sorafenib-resistant AML cells. This upregulation of BCL2 expression rendered the cells vulnerable to the BCL2 inhibitor venetoclax. In conclusion, we developed a platform to predict sorafenib resistance and clinical outcomes in AML patients after therapy. Our findings suggest that the combination of sorafenib and venetoclax could be an effective therapeutic strategy for AML treatment.

Single-cell and genetic multi-omics analysis combined with experiments confirmed the signature and potential targets of cuproptosis in hepatocellular carcinoma

Background: Cuproptosis, as a recently discovered type of programmed cell death, occupies a very important role in hepatocellular carcinoma (HCC) and provides new methods for immunotherapy; however, the functions of cuproptosis in HCC are still unclear. Methods: We first analyzed the transcriptome data and clinical information of 526 HCC patients using multiple algorithms in R language and extensively described the copy number variation, prognostic and immune infiltration characteristics of cuproptosis related genes (CRGs). Then, the hub CRG related genes associated with prognosis through LASSO and Cox regression analyses and constructed a prognostic prediction model including multiple molecular markers and clinicopathological parameters through training cohorts, then this model was verified by test cohorts. On the basis of the model, the clinicopathological indicators, immune infiltration and tumor microenvironment characteristics of HCC patients were further explored via bioinformation analysis. Then, We further explored the key gene biological function by single-cell analysis, cell viability and transwell experiments. Meantime, we also explored the molecular docking of the hub genes. Results: We have screened 5 hub genes associated with HCC prognosis and constructed a prognosis prediction scoring model. And the model results showed that patients in the high-risk group had poor prognosis and the expression levels of multiple immune markers, including PD-L1, CD276 and CTLA4, were higher than those patients in the low-risk group. We found a significant correlation between risk score and M0 macrophages and memory CD4+ T cells. And the single-cell analysis and molecular experiments showed that BEX1 were higher expressed in HCC tissues and deletion inhibited the proliferation, invasion and migration and EMT pathway of HCC cells. Finally, it was observed that BEX1 could bind to sorafenib to form a stable conformation. Conclusion: The study not only revealed the multiomics characteristics of CRGs in HCC but also constructed a new high-accuracy prognostic prediction model. Meanwhile, BEX1 were also identified as hub genes that can mediate the cuproptosis of hepatocytes as potential therapeutic targets for HCC.

GPRC5A regulates proliferation and oxidative stress by inhibiting the STAT3/Socs3/c-MYC pathway in hepatocellular carcinoma

The G protein-coupled receptor, class C, group 5, member A (GPRC5A) plays a key role in various diseases, but its effect on hepatocellular carcinoma (HCC) and the potential underlying mechanisms remains unclear. In the present study, we explored the effect of GPRC5A on the progression of HCC and further explored its mechanism of action. The results revealed that the expression of GPRC5A was lower in HCC tissues and cells. Overexpression of GPRC5A suppressed the proliferation and epithelial-mesenchymal transition (EMT) of HCC cells. In addition, overexpression of GPRC5A induced oxidative stress and apoptosis. Further study showed that overexpression of GPRC5A inhibited the expression of STAT3/Socs3/c-MYC related-protein and the NLRP3 inflammasome. Moreover, the STAT3/Socs3/c-MYC and NLRP3 inflammasome was involved in the effect of GPRC5A on HCC cells. These results suggest that GPRC5A suppresses proliferation and EMT, induces oxidative stress and leads to apoptosis of HCC cells, potentially by regulating STAT3/Socs3/c-MYC signalling and the NLRP3 inflammasome. These findings suggest that GPRC5A has an anti-tumor effect in the formation of HCC, and the molecular therapy of GPRC5A provides a theoretical basis for treating HCC.

Screening and Verification of Key Ubiquitination Genes Related to Immune Infiltration in Stage III/IV Hepatocellular Carcinoma

Introduction

Immune checkpoint therapy (ICIs) effectively improves the prognosis of advanced (stage III/IV) hepatocellular carcinoma (HCC) patients. However, its objective response rate (ORR) is below 20%, significantly limiting ICI use in advanced HCC patients. The level of tumour immune infiltration influences ICI response rate. Recent studies have found ubiquitinase to be an important factor that regulates tumour immune infiltration. Therefore, the aim of this study is to explore the key ubiquitination genes that regulate immune infiltration in advanced HCC and further validate them.

Methods

A biotechnological process was performed as a means of classifying 90 advanced HCC patients into three immune subtypes and identifying associations with immune infiltration in the co-expressed modules. Ubiquitination-related genes were then screened with WGCNA. Gene enrichment analysis was performed for the target module and 30 hub genes were screened out by protein-protein interaction network (PPI). ssGSEA, single-gene sequencing and the MCP counter were used for exploring immune infiltration. TIDE score was applied for predicting drug efficacy and GSEA was used for exploring potential pathways. Finally, GRB2 expression in HCC tissue was validated by in vitro experiments.

Results

GRB2 expression was found to have a significant correlation with the pathological stage and prognosis of HCC patients and a positive correlation with immune infiltration and tumour mutation burden (TMB). In addition, significant correlations with the efficacy of ICIs, sorafenib and transarterial chemoembolization (TACE) were identified. GRB2 was found to be most significantly associated with the JAK-STAT signalling pathway and cytosolic DNA sensing pathway. Finally, it was found that GRB2 expression is closely related to the prognosis, tumour size and TMN stage.

Conclusion

A significant association was observed between the ubiquitinated gene GRB2 and the prognosis and immune infiltration of advanced HCC patients and it may potentially be used for predicting therapy efficacy in advanced HCC patients in the future.

Deciphering STAT3 signaling potential in hepatocellular carcinoma: tumorigenesis, treatment resistance, and pharmacological significance

Hepatocellular carcinoma (HCC) is considered one of the greatest challenges to human life and is the most common form of liver cancer. Treatment of HCC depends on chemotherapy, radiotherapy, surgery, and immunotherapy, all of which have their own drawbacks, and patients may develop resistance to these therapies due to the aggressive behavior of HCC cells. New and effective therapies for HCC can be developed by targeting molecular signaling pathways. The expression of signal transducer and activator of transcription 3 (STAT3) in human cancer cells changes, and during cancer progression, the expression tends to increase. After induction of STAT3 signaling by growth factors and cytokines, STAT3 is phosphorylated and translocated to the nucleus to regulate cancer progression. The concept of the current review revolves around the expression and phosphorylation status of STAT3 in HCC, and studies show that the expression of STAT3 is high during the progression of HCC. This review addresses the function of STAT3 as an oncogenic factor in HCC, as STAT3 is able to prevent apoptosis and thus promote the progression of HCC. Moreover, STAT3 regulates both survival- and death-inducing autophagy in HCC and promotes cancer metastasis by inducing the epithelial-mesenchymal transition (EMT). In addition, upregulation of STAT3 is associated with the occurrence of chemoresistance and radioresistance in HCC. Specifically, non-protein-coding transcripts regulate STAT3 signaling in HCC, and their inhibition by antitumor agents may affect tumor progression. In this review, all these topics are discussed in detail to provide further insight into the role of STAT3 in tumorigenesis, treatment resistance, and pharmacological regulation of HCC.

Ultrasensitive quantification of trace amines based on N-phosphorylation labeling chip 2D LC-QQQ/MS

Trace amines (TAs) are metabolically related to catecholamine and associated with cancer and neurological disorders. Comprehensive measurement of TAs is essential for understanding pathological processes and providing proper drug intervention. However, the trace amounts and chemical instability of TAs challenge quantification. Here, diisopropyl phosphite coupled with chip two-dimensional (2D) liquid chromatography tandem triple-quadrupole mass spectrometry (LC-QQQ/MS) was developed to simultaneously determine TAs and associated metabolites. The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS. This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib. The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells. This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades.

Niclosamide Revitalizes Sorafenib through Insulin-like Growth Factor 1 Receptor (IGF-1R)/Stemness and Metabolic Changes in Hepatocellular Carcinoma

Sorafenib is the first approved systemic targeting agent for advanced HCC; however, when used alone, drug resistance can result in considerably reduced efficacy. Here, we demonstrate that niclosamide, an antihelminthic agent approved by the US Food and Drug Administration, can be repurposed to increase sorafenib sensitivity in sorafenib-resistant HCC cells. We generated sorafenib-resistant HCC cell lines (HepG2215_R and Hep3B_R) with elevated IGF-1R levels and strong properties in terms of stemness and epithelial-mesenchymal transition. Niclosamide was found to increase sorafenib sensitivity effectively in both cell lines and their organoids. The underlying mechanism involves the modulation of cancer stemness, IGF-1R/p-IGF1R/OCT4, and metabolic changes. The combination of sorafenib and niclosamide, but not linsitinib, effectively suppressed the IGF-1R/OCT4 expressions, yielded a synergistic combination index (CI), and attenuated stemness-related properties such as secondary tumor sphere formation and cell migration in sorafenib-resistant HCC cells. Notably, niclosamide significantly suppressed the sorafenib-induced IGF-1R phosphorylation prompted by IGF-1 treatment. Niclosamide effectively downregulated the sorafenib-induced gene expression associated with glycolysis (GLUT1, HK2, LDHA, and PEPCK), stemness (OCT4), and drug resistance (ABCG2) and enhanced the ability of sorafenib to reduce the mitochondrial membrane potential in vitro. The synergistic effect of a combination of niclosamide and sorafenib in vivo was further demonstrated by the decreased tumor size and tumor volume resulting from apoptosis regulation. Our results suggest that niclosamide can enhance sorafenib sensitivity in sorafenib-resistant HCC cells through IGF-1R/stemness regulation and metabolic changes. Our findings highlight a practical clinical strategy for enhancing sorafenib sensitivity in HCC.

Benzobis(imidazole) derivatives as STAT3 signal inhibitors with antitumor activity

Polycyclic aromatic systems have been considered good biological probes, but some may also be good scaffolds for drug development. In this study, a series of benzobis(imidazole) derivatives were identified as STAT3 signal inhibitors, among which compound 24 showed significant inhibition of IL-6 induced JAK/STAT3 signalling pathway activation. Moreover, 24 inhibited cancer cell growth and migration, and induced cell apoptosis as well as cycle arrest in human hepatocellular carcinoma cells (HepG2) and oesophageal carcinoma cells (EC109). Compound 24 also displayed obvious antitumor activity in a mouse HepG2 cell xenograft tumor model without affecting the body weight. These results confirmed that 24 was a potential STAT3 signal inhibitor with certain antitumor activity.

The JAK/STAT signaling pathway: from bench to clinic

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway was discovered more than a quarter-century ago. As a fulcrum of many vital cellular processes, the JAK/STAT pathway constitutes a rapid membrane-to-nucleus signaling module and induces the expression of various critical mediators of cancer and inflammation. Growing evidence suggests that dysregulation of the JAK/STAT pathway is associated with various cancers and autoimmune diseases. In this review, we discuss the current knowledge about the composition, activation, and regulation of the JAK/STAT pathway. Moreover, we highlight the role of the JAK/STAT pathway and its inhibitors in various diseases.

The JAK/STAT signaling pathway: from bench to clinic

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway was discovered more than a quarter-century ago. As a fulcrum of many vital cellular processes, the JAK/STAT pathway constitutes a rapid membrane-to-nucleus signaling module and induces the expression of various critical mediators of cancer and inflammation. Growing evidence suggests that dysregulation of the JAK/STAT pathway is associated with various cancers and autoimmune diseases. In this review, we discuss the current knowledge about the composition, activation, and regulation of the JAK/STAT pathway. Moreover, we highlight the role of the JAK/STAT pathway and its inhibitors in various diseases.

A Yes-Associated Protein (YAP) and Insulin-Like Growth Factor 1 Receptor (IGF-1R) Signaling Loop Is Involved in Sorafenib Resistance in Hepatocellular Carcinoma

The role of a YAP-IGF-1R signaling loop in HCC resistance to sorafenib remains unknown.

METHOD

Sorafenib-resistant cells were generated by treating naïve cells (HepG2215 and Hep3B) with sorafenib. Different cancer cell lines from databases were analyzed through the ONCOMINE web server. BIOSTORM-LIHC patient tissues (46 nonresponders and 21 responders to sorafenib) were used to compare YAP mRNA levels. The HepG2215_R-derived xenograft in SCID mice was used as an in vivo model. HCC tissues from a patient with sorafenib failure were used to examine differences in YAP and IGF-R signaling.

RESULTS

Positive associations exist among the levels of YAP, IGF-1R, and EMT markers in HCC tissues and the levels of these proteins increased with sorafenib failure, with a trend of tumor-margin distribution in vivo. Blocking YAP downregulated IGF-1R signaling-related proteins, while IGF-1/2 treatment enhanced the nuclear translocation of YAP in HCC cells through PI3K-mTOR regulation. The combination of YAP-specific inhibitor verteporfin (VP) and sorafenib effectively decreased cell viability in a synergistic manner, evidenced by the combination index (CI).

CONCLUSION

A YAP-IGF-1R signaling loop may play a role in HCC sorafenib resistance and could provide novel potential targets for combination therapy with sorafenib to overcome drug resistance in HCC.

Ginsenoside Rg3 in combination with artesunate overcomes sorafenib resistance in hepatoma cell and mouse models

Background

Sorafenib is effective in treating hepatoma, but most patients develop resistance to it. STAT3 signaling has been implicated in sorafenib resistance. Artesunate (ART) and 20(R)-ginsenoside Rg3 (Rg3) have anti-hepatoma effects and can inhibit STAT3 signaling in cancer cells. This study aimed to evaluate the effects of Rg3 in combination with ART (Rg3-plus-ART) in overcoming sorafenib resistance, and to examine the involvement of STAT3 signaling in these effects.

Methods

Sorafenib-resistant HepG2 cells (HepG2-SR) were used to evaluate the in vitro anti-hepatoma effects of Rg3-plus-ART. A HepG2-SR hepatoma-bearing BALB/c-nu/nu mouse model was used to assess the in vivo anti-hepatoma effects of Rg3-plus-ART. CCK-8 assays and Annexin V-FITC/PI double staining were used to examine cell proliferation and apoptosis, respectively. Immunoblotting was employed to examine protein levels. ROS generation was examined by measuring DCF-DA fluorescence.

Results

Rg3-plus-ART synergistically reduced viability of, and evoked apoptosis in HepG2-SR cells, and suppressed HepG2-SR tumor growth in mice. Mechanistic studies revealed that Rg3-plus-ART inhibited activation/phosphorylation of Src and STAT3 in HepG2-SR cultures and tumors. The combination also decreased the STAT3 nuclear level and induced ROS production in HepG2-SR cultures. Furthermore, over-activation of STAT3 or removal of ROS diminished the anti-proliferative effects of Rg3-plus-ART, and removal of ROS diminished Rg3-plus-ART's inhibitory effects on STAT3 activation in HepG2-SR cells.

Conclusions

Rg3-plus-ART overcomes sorafenib resistance in experimental models, and inhibition of Src/STAT3 signaling and modulation of ROS/STAT3 signaling contribute to the underlying mechanisms. This study provides a pharmacological basis for developing Rg3-plus-ART into a novel modality for treating sorafenib-resistant hepatoma.

Oxidative Stress Activated by Sorafenib Alters the Temozolomide Sensitivity of Human Glioma Cells Through Autophagy and JAK2/STAT3-AIF Axis

The development of temozolomide (TMZ) resistance in glioma leads to poor patient prognosis. Sorafenib, a novel diaryl urea compound and multikinase inhibitor, has the ability to effectively cross the blood-brain barrier. However, the effect of sorafenib on glioma cells and the molecular mechanism underlying the ability of sorafenib to enhance the antitumor effects of TMZ remain elusive. Here, we found that sorafenib could enhance the cytotoxic effects of TMZ in glioma cells in vitro and in vivo. Mechanistically, the combination of sorafenib and TMZ induced mitochondrial depolarization and apoptosis inducing factor (AIF) translocation from mitochondria to nuclei, and this process was dependent on STAT3 inhibition. Moreover, the combination of sorafenib and TMZ inhibited JAK2/STAT3 phosphorylation and STAT3 translocation to mitochondria. Inhibition of STAT3 activation promoted the autophagy-associated apoptosis induced by the combination of sorafenib and TMZ. Furthermore, the combined sorafenib and TMZ treatment induced oxidative stress while reactive oxygen species (ROS) clearance reversed the treatment-induced inhibition of JAK2/STAT3. The results indicate that sorafenib enhanced the temozolomide sensitivity of human glioma cells by inducing oxidative stress-mediated autophagy and JAK2/STAT3-AIF axis.

Critical signaling pathways governing hepatocellular carcinoma behavior; small molecule-based approaches

Hepatocellular carcinoma (HCC) is the second leading cause of death due to cancer. Although there are different treatment options, these strategies are not efficient in terms of restricting the tumor cell's proliferation and metastasis. The liver tumor microenvironment contains the non-parenchymal cells with supportive or inhibitory effects on the cancerous phenotype of HCC. Several signaling pathways are dis-regulated in HCC and cause uncontrolled cell propagation, metastasis, and recurrence of liver carcinoma cells. Recent studies have established new approaches for the prevention and treatment of HCC using small molecules. Small molecules are compounds with a low molecular weight that usually inhibit the specific targets in signal transduction pathways. These components can induce cell cycle arrest, apoptosis, block metastasis, and tumor growth. Devising strategies for simultaneously targeting HCC and the non-parenchymal population of the tumor could lead to more relevant research outcomes. These strategies may open new avenues for the treatment of HCC with minimal cytotoxic effects on healthy cells. This study provides the latest findings on critical signaling pathways governing HCC behavior and using small molecules in the control of HCC both in vitro and in vivo models.

Inflammatory microenvironment of fibrotic liver promotes hepatocellular carcinoma growth, metastasis and sorafenib resistance through STAT3 activation

The pro‐inflammatory and pro‐fibrotic liver microenvironment facilitates hepatocarcinogenesis. However, the effects and mechanisms by which the hepatic fibroinflammatory microenvironment modulates intrahepatic hepatocellular carcinoma (HCC) progression and its response to systematic therapy remain largely unexplored. We established a syngeneic orthotopic HCC mouse model with a series of persistent liver injury induced by CCl₄ gavage, which mimic the dynamic effect of hepatic pathology microenvironment on intrahepatic HCC growth and metastasis. Non‐invasive bioluminescence imaging was applied to follow tumour progression over time. The effect of the liver microenvironment modulated by hepatic injury on sorafenib resistance was investigated in vivo and in vitro. We found that the persistent liver injury facilitated HCC growth and metastasis, which was positively correlated with the degree of liver inflammation rather than the extent of liver fibrosis. The inflammatory cytokines in liver tissue were clearly increased after liver injury. The two indicated cytokines, tumour necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6), both promoted intrahepatic HCC progression via STAT3 activation. In addition, the hepatic inflammatory microenvironment contributed to sorafenib resistance through the anti‐apoptotic protein mediated by STAT3, and STAT3 inhibitor S3I‐201 significantly improved sorafenib efficacy impaired by liver inflammation. Clinically, the increased inflammation of liver tissues was accompanied with the up‐regulated STAT3 activation in HCC. Above all, we concluded that the hepatic inflammatory microenvironment promotes intrahepatic HCC growth, metastasis and sorafenib resistance through activation of STAT3.

Role of hydrogen sulfide donors in cancer development and progression

In recent years, a vast number of potential cancer therapeutic targets have emerged. However, developing efficient and effective drugs for the targets is of major concern. Hydrogen sulfide (H2S), one of the three known gasotransmitters, is involved in the regulation of various cellular activities such as autophagy, apoptosis, migration, and proliferation. Low production of H2S has been identified in numerous cancer types. Treating cancer cells with H2S donors is the common experimental technique used to improve H2S levels; however, the outcome depends on the concentration/dose, time, cell type, and sometimes the drug used. Both natural and synthesized donors are available for this purpose, although their effects vary independently ranging from strong cancer suppressors to promoters. Nonetheless, numerous signaling pathways have been reported to be altered following the treatments with H2S donors which suggest their potential in cancer treatment. This review will analyze the potential of H2S donors in cancer therapy by summarizing key cellular processes and mechanisms involved.

Sorafenib and CuB exert synergistic antitumor effects against hepatocellular carcinoma cells via inhibition of STAT3 phosphorylation

Sorafenib, the first‐line agent for treatment of advanced hepatocellular carcinoma (HCC), improves median overall survival by approximately 3 months. In the present study, we investigated whether sorafenib combined with cucurbitacin B (CuB), a natural tetracyclic triterpenoid isolated from Cucurbitaceae, exerts enhanced antitumor effects against HCC. Cell viability and colony formation ability were detected by cell‐counting kit‐8 and colony formation assays. Cell cycle and apoptosis were analyzed by flow cytometry. Protein expression was detected by western blotting. HepG2 xenografts in nude mice were used to evaluate in vivo antitumor effects. We report that sorafenib and CuB exhibited synergistic effects on cellular proliferation inhibition and cell apoptosis induction, but not on cell cycle arrest. Furthermore, combination treatment enhanced levels of cleaved caspase 3 and cleaved caspase 9, but suppressed phosphorylation of STAT3. Epidermal growth factor, a potent stimulator of signal transducer and activator of transcription‐3 (STAT3), promoted cell viability and colony formation ability, whereas combination treatment exerted inhibitory effects on epidermal growth factor‐induced STAT3 phosphorylation. Finally, HepG2 xenograft mice cotreated with sorafenib and CuB exhibited reduced tumor progression without notable weight loss. In conclusion, sorafenib and CuB exert synergistic antitumor effects through a pathway that may involve STAT3 phosphorylation, and this may represent a promising therapeutic approach for treatment of HCC.

Berbamine (BBM), a Natural STAT3 Inhibitor, Synergistically Enhances the Antigrowth and Proapoptotic Effects of Sorafenib on Hepatocellular Carcinoma Cells

Sorafenib (SORA), a multi kinase inhibitor, is the standard first-line targeted therapy approved by the Food and Drug Administration for advanced hepatocellular carcinoma (HCC). However, emerging evidence from clinical practice indicates that SORA alone has only moderate antitumor effects and could not completely inhibit the progression of the disease. Therefore, it is very necessary and urgent to develop novel combination therapy to improve the clinical outcomes of SORA. The pharmacological study on the chemosensitizing effects of natural products has become a hotspot in recent years, which is commonly thought to be a potential way to improve the effectiveness of drugs in clinical use. Berbamine (BBM) has potential sensitizing effects in multiple chemotherapies and target therapy. However, it remains unclarified whether the combination of BBM and SORA as a treatment could exert a synergistic effect on HCC cell lines. In this study, we first investigated whether BBM can increase the sensitivity of HCC cell lines to SORA. The results revealed that the combination of BBM and SORA could synergistically inhibit the growth of two HCC cell lines and promoted their apoptosis. Mechanistically, our results showed that BBM exerted a dose-dependent inhibitory effect on the basal and IL-6-induced STAT3 activation of HCC cell lines. In addition, the combined treatment of BBM and SORA synergistically suppressed STAT3 phosphorylation at Tyr705 and knockdown of STAT3 abolished the sensitization effect of BBM, indicating that BBM's sensitization effect is mainly mediated by its inhibition of STAT3. These findings identify a new type of natural STAT3 inhibitor and provide a novel approach to the enhancement of SORA efficacy by blocking the activation of STAT3.

Liraglutide activates nature killer cell-mediated antitumor responses by inhibiting IL-6/STAT3 signaling in hepatocellular carcinoma

Inflammatory IL-6/STAT3 signaling is constitutively activated in diverse cancers and is associated with malignant cell proliferation, invasion and escape of antitumor immunosurveillance. Liraglutide, a glucagon-like peptide-1 (GLP-1) analog, is commonly used to treat insulin-resistant diabetes. In this study, for the first time, we showed that liraglutide remarkably improved the antitumor immune responses in hepatocellular carcinoma (HCC). Furthermore, we showed that the antitumor activity was mediated by nature killer cells (NKs) but not CD8⁺ T cells. Finally, we showed that liraglutide enhanced NK-mediated cytotoxicity by suppressing the IL-6/STAT3 signaling pathway in HCC cells. Our findings unveil a novel therapeutic role of liraglutide by manipulating the innate immunity in cancer therapy.

STAT3 transcription factor as target for anti-cancer therapy

STATs constitute a large family of transcription activators and transducers of signals that have an important role in many cell functions as regulation of proliferation and differentiation of the cell also regulation of apoptosis and angiogenesis. STAT3 as a member of that family, recently was discovered to have a vital role in progression of different types of cancers. The activation of STAT3 was observed to regulate multiple gene functions during cancer-like cell proliferation, differentiation, apoptosis, metastasis, inflammation, immunity, cell survival, and angiogenesis. The inhibition of STAT3 activation has been an important target for cancer therapy. Inhibitors of STAT3 have been used for a long time for treatment of many types of cancers like leukemia, melanoma, colon, and renal cancer. In this review article, we summarize and discuss different drugs inhibiting the action of STAT3 and used in treatment of different types of cancer.

Targeting the JAK/STAT pathway in solid tumors

Aberrant activation of signal transducer and activator of transcription (STAT) proteins is associated with the development and progression of solid tumors. However, as transcription factors, these proteins are difficult to target directly. In this review, we summarize the role of targeting Janus kinases (JAKs), upstream activators of STATs, as a strategy for decreasing STAT activation in solid tumors. Preclinical studies in solid tumor cell line models show that JAK inhibitors decrease STAT activation, cell proliferation, and cell survival; in in vivo models, they also inhibit tumor growth. JAK inhibitors, particularly the JAK1/2 inhibitor ruxolitinib, sensitize cell lines and murine models to chemotherapy, immunotherapy, and oncolytic viral therapy. Ten JAK inhibitors have been or are actively being tested in clinical trials as monotherapy or in combination with other agents in patients with solid tumors; two of these inhibitors are already Food and Drug Administration (FDA) approved for the treatment of myeloproliferative disorders and rheumatoid arthritis, making them attractive agents for use in patients with solid tumors as they are known to be well-tolerated. Four JAK inhibitors (two of which are FDA approved for other indications) have exhibited promising anti-cancer effects in preclinical studies; however, clinical studies specifically assessing their activity against the JAK/STAT pathway in solid tumors have not yet been conducted. In summary, JAK inhibition is a viable option for targeting the JAK/STAT pathway in solid tumors and merits further testing in clinical trials.

JAK/STAT signaling in hepatocellular carcinoma

Liver cancer is the second most lethal cancer in the world with limited treatment options. Hepatocellular carcinoma (HCC), which accounts for more than 80% of all liver cancers, has had increasing global incidence over the past few years. There is an urgent need for novel and better therapeutic intervention for HCC patients. The JAK/STAT signaling pathway plays a multitude of important biological functions in both normal and malignant cells. In a subset of HCC, JAK/STAT signaling is aberrantly activated, leading to dysregulation of downstream target genes that controls survival, angiogenesis, stemness, immune surveillance, invasion and metastasis. In this review, we will focus on the role of JAK/STAT signaling in HCC and discuss the current clinical status of several JAK/STAT inhibitors.

LncRNA DANCR Promotes Sorafenib Resistance via Activation of IL-6/STAT3 Signaling in Hepatocellular Carcinoma Cells

Background

Hepatocellular carcinoma (HCC) is one of the major malignancies and the second most common cause of cancer-related death worldwide. Sorafenib, an approved first-line systematic treatment agent for HCC, is capable to effectively improve the survival of patients with advanced HCC. The long-noncoding RNA (lncRNA) differentiation antagonizing non-protein coding RNA (DANCR) has been reported to exert oncogenic functions in several kinds of human cancers. However, the role of lncRNA DANCR in sorafenib resistance in HCC remains unknown.

Methods

The expression levels of DANCR in HCC tissues were detected by qRT-PCR. DANCR overexpression and knockdown models were established and utilized to investigate the functional role of DANCR on sorafenib resistance in HCC cells. The MS2-binding sequences-MS2-binding protein–based RNA immunoprecipitation assay, RNA pull-down and luciferase reporter assay was used to detect the association between DANCR and PSMD10 mRNA. The activation of DANCR transcription mediated by STAT3 was assessed by luciferase reporter and chromatin immunoprecipitation assays.

Results

We found that DANCR was significantly overexpressed in HCC tissues and associated with prognosis of HCC patients. Overexpression and knockdown experiments demonstrated that DANCR promoted sorafenib resistance in HCC cells in vitro and in vivo. Mechanistically, the role of DANCR relied largely on the association with PSMD10. DANCR stabilized PSMD10 mRNA through blocking the repressing effect of several microRNAs on PSMD10. Besides, DANCR activated IL-6/STAT3 signaling via PSMD10. Furthermore, we revealed that DANCR transcription was enhanced by the activation of IL-6/STAT3 signaling, indicating a positive feedback loop of DANCR and IL-6/STAT3 signaling.

Conclusion

Collectively, our study is the first to elucidate the mechanism of DANCR-mediated sorafenib resistance via PSMD10-IL-6/STAT3 signaling axis, which provides a promising target for developing new therapeutic strategy for sorafenib tolerance of HCC.

Modulation of the IL-6-Signaling Pathway in Liver Cells by miRNAs Targeting gp130, JAK1, and/or STAT3

Interleukin-6 (IL-6)-type cytokines share the common receptor glycoprotein 130 (gp130), which activates a signaling cascade involving Janus kinases (JAKs) and signal transducer and activator of transcription (STAT) transcription factors. IL-6 and/or its signaling pathway is often deregulated in diseases, such as chronic liver diseases and cancer. Thus, the identification of compounds inhibiting this pathway is of interest for future targeted therapies. We established novel cellular screening systems based on a STAT-responsive reporter gene (Cypridina luciferase). Of a library containing 538 microRNA (miRNA) mimics, several miRNAs affected hyper-IL-6-induced luciferase activities. When focusing on candidate miRNAs specifically targeting 3′ UTRs of signaling molecules of this pathway, we identified, e.g., miR-3677-5p as a novel miRNA affecting protein expression of both STAT3 and JAK1, whereas miR-16-1-3p, miR-4473, and miR-520f-3p reduced gp130 surface expression. Interestingly, combination treatment with 2 or 3 miRNAs targeting gp130 or different signaling molecules of the pathway did not increase the inhibitory effects on phospho-STAT3 levels and STAT3 target gene expression compared to treatment with single mimics. Taken together, we identified a set of miRNAs of potential therapeutic value for cancer and inflammatory diseases, which directly target the expression of molecules within the IL-6-signaling pathway and can dampen inflammatory signal transduction.

Repression of GRIM19 expression potentiates cisplatin chemoresistance in advanced bladder cancer cells via disrupting ubiquitination-mediated Bcl-xL degradation

OBJECTIVE

The mainstay of treatment for advanced bladder cancer (BC) is cisplatin (CDDP)-based systematic chemotherapy. However, acquired chemoresistance induced by as yet unidentified mechanisms is encountered frequently and often results in treatment failure and disease progression. The present study was designed to elucidate the expression and potential role of the gene associated with retinoid-interferon-induced mortality-19 (GRIM19) in the pathogenesis of CDDP resistance in BC.

METHODS

RT-qPCR and immunoblotting were employed to evaluate the expression profile of GRIM19 in clinical BC samples and in different BC cells. Using cell viability assay, apoptotic ELISA, xenografts mouse model, and Transwell assay, the effects of GRIM19 inhibition or GRIM19 overexpression on CDDP resistance were determined in different BC cells. Lastly, using co-immunoprecipitation, we provided the molecular evidence for the interaction between GRIM19 and Bcl-xL.

RESULTS

Expression levels of GRIM19 were significantly down-regulated in recurrent BC specimens, and in experimentally induced CDDP-resistant BC cells. Functionally, overexpression of the exogenous GRIM19 potentiated CDDP sensitivity and suppressed the survival and invasion of BC cells in the presence of CDDP challenge. Mechanistically, the compromised CDDP chemosensitization induced by GRIM19 loss was at least partially attributed to the attenuation of Bcl-xL polyubiquitination and subsequent degradation, because (1) GRIM19 colocalized with Bcl-xL in the mitochondria of BC cells and (2) GRIM19 overexpression promoted the ubiquitination of Bcl-xL, and this event could be effectively reversed by pretreatment with inhibitors of p38-MAPK and JNK pathways, indicating that GRIM19 overexpression-induced Bcl-xL ubiquitination may achieve in a p38/JNK-dependent manner. Using the UMUC-3 cells stably depleted of endogenous GRIM19, we further show that inhibition of Bcl-xL rectified GRIM19 deficiency-caused CDDP resistance in BC cells. In addition, BCL2L1 mRNA levels were negatively correlated with GRIM19 mRNA levels in CDDP-associated clinical BC tissues.

CONCLUSIONS

Disruption of GRIM19/Bcl-xL is a key mechanism of CDDP resistance in advanced BC. Therapeutically, enhancement of GRIM19 expression or employment of p38/JNK inhibitors may serve as resensitizing therapies for subgroups of CDDP-resistant or refractory BC patients.