Chemoresistance Of Liver Cancer Research Articles

Identification of SPP1+ macrophages in promoting cancer stemness via vitronectin and CCL15 signals crosstalk in liver cancer

Macrophages play a multifaceted role in cancer biology, with both pro-tumorigenic and anti-tumorigenic functions. Understanding the mechanisms underlying macrophage involvement in cancer progression is essential for the development of therapeutic strategies. Our study analyzed single-cell RNA sequencing data from 12 patients with liver cancer and identified a subpopulation of macrophages characterized by elevated expression of SPP1, which correlates with poor prognosis in liver cancer patients. These SPP1+ macrophages induce upregulation of tumor stemness through a vitronectin (VTN)-dependent paracrine mechanism. Mechanistically, VTN derived from SPP1+ macrophages promote integrin αvβ5/adenosine 5‘-monophosphate-activated protein kinase (AMPK)/Yes-associated protein 1 (YAP1)/SYR-box transcription factor 4 (SOX4) signaling, mediating liver tumor stemness and progression. Conversely, CCL15 produced by liver cancer cells drives polarization of M0 macrophages toward an SPP1+ macrophage phenotype, establishing a positive feedback loop of macrophage-tumor stemness. Furthermore, the presence of SPP1+ macrophages confers chemoresistance in liver cancer, and inhibition of the macrophage-tumor feedback loop through targeting integrin αvβ5/YAP1 signaling sensitizes liver cancer cells to chemotherapy. Our study highlights the crucial role of SPP1+ macrophages in liver cancer progression, providing novel insights for clinical liver cancer therapy.

DPP9 regulates NQO1 and ROS to promote resistance to chemotherapy in liver cancer cells

Chemotherapy has been the standard treatment for liver cancer. However, intrinsic or acquired drug resistance remains a major barrier to successful treatment. At present, the underlying molecular mechanisms of chemoresistance in liver cancer have not been elucidated. Dipeptidyl peptidase 9 (DPP9) is a member of the dipeptidyl peptidase IV family that has been found to be highly expressed in a variety of tumors, including liver cancer. It is unclear whether DPP9 affects chemoresistance in liver cancer. In this study, we find that DPP9 weakens the responses of liver cancer cells to chemotherapy drugs by up-regulating NQO1 and inhibiting intracellular ROS levels. In terms of mechanism, DPP9 inhibits ubiquitin-mediated degradation of NRF2 protein by binding to KEAP1, up-regulates NRF2 protein levels, promotes mRNA transcription of NQO1, and inhibits intracellular ROS levels. In addition, the NQO1 inhibitor dicoumarol can enhance the efficacy of chemotherapy drugs in liver cancer cells. Collectively, our findings suggest that inhibiting DPP9/NQO1 signaling can serve as a potential therapeutic strategy for liver cancer.

Strategies to enhance the response of liver cancer to pharmacological treatments.

In contrast to other types of cancers, there is no available efficient pharmacological treatment to improve the outcomes of patients suffering from major primary liver cancers, i.e., hepatocellular carcinoma and cholangiocarcinoma. This dismal situation is partly due to the existence in these tumors of many different and synergistic mechanisms of resistance, accounting for the lack of response of these patients, not only to classical chemotherapy but also to more modern pharmacological agents based on the inhibition of tyrosine kinase receptors (TKIs) and the stimulation of the immune response against the tumor using immune checkpoint inhibitors (ICIs). This review summarizes the efforts to develop strategies to overcome this severe limitation, including searching for novel drugs derived from synthetic, semisynthetic, or natural products with vectorial properties against therapeutic targets to increase drug uptake or reduce drug export from cancer cells. Besides, immunotherapy is a promising line of research that is already starting to be implemented in clinical practice. Although less successful than in other cancers, the foreseen future for this strategy in treating liver cancers is considerable. Similarly, the pharmacological inhibition of epigenetic targets is highly promising. Many novel "epidrugs," able to act on "writer," "reader," and "eraser" epigenetic players, are currently being evaluated in preclinical and clinical studies. Finally, gene therapy is a broad field of research in the fight against liver cancer chemoresistance, based on the impressive advances recently achieved in gene manipulation. In sum, although the present is still dismal, there is reason for hope in the non-too-distant future.

MiR‑122/SENP1 axis confers stemness and chemoresistance to liver cancer through Wnt/β‑catenin signaling.

The property of inherent stemness of tumor cells coupled with the development of chemoresistance results in a poor prognosis for patients with liver cancer. Therefore, the present study focused on microRNA (miR)-122, a potential tumor suppressor, the expression of which has been previously shown to be significantly decreased and negatively associated with cancer cell stemness in liver cancer. The present study aimed to identify the molecular targets of miR-122 whilst uncovering the mechanism underlying chemoresistance and stemness of HepG2 cells in liver cancer. Bioinformatics online tools, such as ENCORI, coupled with dual-luciferase reporter assays in HepG2 cells, were used to identify and validate small ubiquitin-like modifier (SUMO) specific peptidase 1 (SENP1) as a potential target of miR-122 in liver cancer. The liver cancer stem cell population was determined using sphere formation assays and flow cytometry, whilst stem cell markers (Oct3/4, Nanog, B lymphoma Mo-MLV insertion region 1 homolog and Notch1) were detected by reverse transcription-quantitative PCR. Chemoresistance, cell proliferation and migratory ability of HepG2 cells were monitored using Cell Counting Kit-8, colony formation and Transwell assays, respectively. The overexpression of miR-122 by mimic transfection led to a significant decrease in the number spheres, downregulation of stem cell marker expression, the number of CD24+ cells, drug-resistance protein levels (P-glycoprotein and multidrug resistance protein), impaired chemoresistance, proliferation and migration of HepG2 cells. The transfection of SENP1 overexpression vector resulted in contrasting functions to miR-122 mimics, by partially reversing the effects induced by miR-122 mimic transfection in HepG2 cells. Wnt/β-catenin signaling has been proven to be involved in cancer stemness and malignant behavior. Western blotting analysis in HepG2 cells showed that the expression levels of both Wnt1 and β-catenin were significantly reduced after overexpressing miR-122, but increased after overexpressing SENP1. Co-transfection with the SENP1 overexpression vector reversed the suppression induced by the miR-122 mimics on Wnt1 and β-catenin expression. Co-immunoprecipitation, SUMOylation and half-life assays showed SENP1 interacted with β-catenin and decreased the SUMOylation of β-catenin, thereby enhancing its stability. Finally, tumor xenograft analyses revealed that HepG2 cells transfected with Agomir-122 exerted significantly lower tumor initiation frequency and growth rate, and a superior response to DOX in vivo, compared with those transfected with Agomir NC. Taken together, data from the present study miR-122/SENP1 axis can regulate β-catenin stability through de-SUMOylation, thereby promoting stemness and chemoresistance in liver cancer.

MRNA sequencing and CyTOF analysis revealed ASPP2 altered the response patterns of hepatocellular carcinoma HepG2 cells to usnic acid.

In a previous study, our team found that ASPP2 overexpression increases the sensitivity of liver cancer cells to sorafenib. ASPP2 is an important target in the study of drug therapy for hepatocellular carcinoma. In this study, we demonstrated that ASPP2 altered the response of HepG2 cells to usnic acid (UA) by using mRNA sequencing and CyTOF. CCK8 assay was used to detect cytotoxicity of UA on HepG2 cells. Annexin V-RPE assay, TUNEL assay, and cleaved caspase 3 assay were performed to examine the apoptotic cell death induced by UA. Transcriptomic sequencing and a single-cell mass cytometry were used to analyze the dynamic response of HepG2shcon and HepG2shASPP2 cells to UA treatment. We have demonstrated that UA could inhibit proliferation in HepG2 cells in a concentration-dependent manner. Apoptotic cell death was significantly induced by UA in HepG2 cells, while knocking down ASPP2 could increase the resistance of HepG2 cells to UA. Data from mRNA-Seq indicated that knockout of ASPP2 in HepG2 cells affected cell proliferation, cycle, and metabolism. ASPP2 knockdown resulted in increased stemness and decreased apoptosis of HepG2 cells under the action of UA. CyTOF analysis confirmed the above results, ASPP2 knockdown increased oncoproteins in HepG2 cells and altered response patterns of HepG2 cells to UA. Our data suggested that the natural compound UA could inhibit liver cancer HepG2 cells; meanwhile, ASPP2 knockdown could affect response patterns of HepG2 cells to UA. The above results indicate that ASPP2 could be a research target in the chemoresistance of liver cancer.

P4HB modulates epithelial-mesenchymal transition and the β-catenin/Snail pathway influencing chemoresistance in liver cancer cells.

The aim of the present study was to investigate the role of prolyl 4-hydroxylase beta polypeptide (P4HB) in the chemoresistance of liver cancer. Drug-resistant liver cancer cell lines, such as HepG2/adriamycin (ADR) cells, were treated and screened using adriamycin. Gene interference was used to silence the expression of P4HB in liver cancer cells. Cell viability, invasiveness and migration were assessed using CCK8, Transwell and wound healing assays, respectively. In addition, changes to key genes and proteins in the epithelial-mesenchymal transition (EMT) and β-catenin/Snail pathway were analyzed using reverse transcription-quantitative PCR and western blotting. Drug-resistant HepG2/ADR cells were successfully cultivated; the IC50 to ADR for HepG2/ADR and HepG2 cell lines was 4.85 and 0.61 µM, respectively. HepG2/ADR cells exhibited higher invasion and migration abilities compared with HepG2 cells (P<0.05). E-cadherin mRNA and protein expression levels in HepG2/ADR cells were decreased significantly, whereas P4HB, N-cadherin and vimentin mRNA and protein levels were significantly increased compared with HepG2 cells (all P<0.05). Knockdown of P4HB significantly decreased cell viability and the invasion and migration ability of HepG2/ADR cells. In addition, P4HB knockdown enhanced E-cadherin mRNA and protein expression levels, whereas N-cadherin, vimentin, total β-catenin, nuclear β-catenin and Snail mRNA and protein levels were significantly decreased (all P<0.05). Overall, the present study demonstrated that EMT and β-catenin/Snail pathway influence P4HB modulation in liver cancer chemoresistance.

TGF-β induced chemoresistance in liver cancer is modulated by xenobiotic nuclear receptor PXR

ABSTRACT Hepatocellular carcinoma appears as an extremely angiogenic solid tumor marked by apoptosis evasion, dysregulated cell cycle and low sensitivity to chemotherapy. TGF-β, a multifunctional cytokine, plays a pleiotropic role in the tumor microenvironment and has implications in cancer drug resistance. The current study provides novel evidence that TGF-β signaling contributes to drug resistance in liver cancer cells by inducing the expression of xenobiotic nuclear receptor PXR. We observed that PXR increases the expression of drug efflux transporters; therefore, accounting for exacerbated drug resistance. Additionally, anti-apoptotic nature of PXR contributes to TGF-β mediated chemoresistance as seen by procaspase-3 and Mcl-1 cellular levels. TGF-β binding to the TGF-β receptor triggers a complex downstream signaling cascade through a non-canonical SMAD-independent ERK pathway that leads to increased PXR expression. Activated ERK activates ETS1 transcription factor which is a critical regulator of endogenous PXR expression in hepatic cells. Loss of function of ETS1 abrogates the TGF-β induced PXR expression. Together these findings indicate that PXR modulates TGF-β induced resistance to chemotherapy in liver cancer cells. This underscores the need for combinatorial approaches with focus on PXR antagonism to improve drug effectiveness in hepatocellular carcinoma. Abbreviations HCC: Hepatocellular Carcinoma; FDA: Food and Drug Administration; TGF-β: Transforming growth factor-β; PXR: Pregnane X receptor; CAR: Constitutive androstane receptor; P-gp/ABCB1: P-glycoproteins/ATP-binding cassette transporter subfamily B member 1; MRP1/ABCC1 and MRP2/ABCC2: Multidrug-resistance associated proteins; BCRP/ABCG2: Breast cancer resistant protein; DMEs: Drug-metabolizing enzymes; CFDA: 5,6-carboxyfluorescein diacetate; ETS1: Transcription factor E26 transformation specific sequence 1.

Saikosaponin-d Inhibits the Hepatoma Cells and Enhances Chemosensitivity Through SENP5-Dependent Inhibition of Gli1 SUMOylation Under Hypoxia.

Chemosensitivity is one of the key factors affecting the therapeutic effect on cancer, but the clinical application of corresponding drugs is rare. Hypoxia, a common feature of many solid tumors, including hepatocellular carcinoma (HCC), has been associated with resistance to chemotherapy in part through the activation of the Sonic Hedgehog (SHh) pathway. Hypoxia has also been associated with the increased SUMOylation of multiple proteins, including GLI family proteins, which are key mediators of SHh signaling, and has become a promising target to develop drug-resistant drugs for cancer treatment. However, there are few target drugs to abrogate chemotherapy resistance. Saikosaponin-d (Ssd), one of the main bioactive components of Radix bupleuri, has been reported to exert multiple biological effects, including anticancer activity. Here, we first found that Ssd inhibits the malignant phenotype of HCC cells while increasing their sensitivity to the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) drug system under hypoxia in vitro and in vivo. Furthermore, we had explored that GLI family activation and extensive protein SUMOylation were characteristics of HCC cells, and hypoxia could activate the SHh pathway and promote epithelial-mesenchymal transition (EMT), invasion, and chemosensitivity in HCC cells. SUMOylation is required for hypoxia-dependent activation of GLI proteins. Finally, we found that Ssd could reverse the effects promoted by hypoxia, specifically active sentrin/small ubiquitin-like modifier (SUMO)-specific protease 5 (SENP5), a SUMO-specific protease, in a time- and dose-dependent manner while inhibiting the expression of SUMO1 and GLI proteins. Together, these findings confirm the important role of Ssd in the chemoresistance of liver cancer, provide some data support for further understanding the molecular mechanisms of Ssd inhibition of malignant transformation of HCC cells, and provide a new perspective for the application of traditional Chinese medicine in the chemical resistance of liver cancer.

PDCD2 sensitizes HepG2 cells to sorafenib by suppressing epithelial‑mesenchymal transition.

Epithelial-mesenchymal transition (EMT) has an established role in the acquisition of therapeutic resistance. Programmed cell death domain 2 (PDCD2) is involved in the progression of multiple types of cancer. However, its mechanism underlying chemoresistance in liver cancer has not been elucidated. In the present study, it was demonstrated that the sorafenib-resistant HepG2 cell line exhibited EMT and multidrug resistance (MDR) phenotypes, and reduced expression of PDCD2, by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot analysis and Cell Counting Kit-8. Annexin V/fluorescein isothiocyanate and cell migration assays further demonstrated that PDCD2 effectively promoted sorafenib-induced cell apoptosis and reduced cell metastasis. Mechanistically, PDCD2 inhibited the expression of Vimentin and increased the expression of E-cadherin in a Snail-dependent manner by RT-qPCR and western blot analysis. In conclusion, the present study elucidated for the first time, to the best of our knowledge, that PDCD2 sensitizes sorafenib-resistant HepG2 cells to sorafenib by the downregulation of EMT. PDCD2 may serve as a potential therapeutic target in the treatment of sorafenib-resistant liver cancer.

Targeting PRMT5 Activity Inhibits the Malignancy of Hepatocellular Carcinoma by Promoting the Transcription of HNF4α.

Background: Liver cancer stem cells (LCSCs) are responsible for the initiation, progression and chemoresistance of liver cancer. However, no agent targeting LCSC is available in the clinic to date. Here, we investigated the effects of targeting protein arginine methyltransferase 5 (PRMT5), an epigenetic regulator, on LCSCs and HCC using a novel PRMT5 inhibitor DW14800.Methods: Tumor spheroid formation culture was used to enrich LCSCs and assess their self-renewal capability. Human alpha-1-antitrypsin (A1AT) ELISA, acetylated low-density lipoprotein (ac-LDL) uptake, periodic acid-Schiff (PAS) reactions and senescence associated β-galactosidase (SA-β-gal) activity assays were performed to examine the differentiation status of HCC cells. The effects of DW14800 on HCC malignancy were assessed in HCC cell lines and on an HCC xenograft model in mice. Chromatin immunoprecipitation was applied to clarify the transcriptional regulation of HNF4α by PRMT5-mediated Histone H4 arginine-3 symmetrical dimethylation (H4R3me2s).Results: Quantitative real-time PCR revealed that the expression of PRMT5 was upregulated in LCSCs. DW14800 specifically decreased the symmetrical dimethylation of arginine residues in HCC cells. Treatment of DW14800 suppressed the self-renewal capacity of LCSCs while re-establishing hepatocyte-specific characteristics in HCC cells. DW14800 displayed antitumor effects in HCC cells in vitro and in xenograft HCC in vivo. Importantly, ChIP assay showed that PRMT5 and H4R3me2s bound to the promoter region of HNF4α gene, and DW14800 increased the expression of HNF4α via reducing the H4R3me2s levels and enhancing the transcription of HNF4α.Conclusions: Our data revealed the significance of targeting PRMT5 activity in LCSC elimination and HCC differentiation, and proposed that DW14800 may represent a promising therapeutic agent for HCC in the clinic.

MicroRNA-29c restores cisplatin sensitivity in liver cancer through direct inhibition of sirtuin 1 expression.

Liver cancer is one of the most prevalent human tumors in the world. Despite recent advances regarding the understanding of the molecular basis of liver cancer and the introduction of novel chemotherapeutic approaches, liver cancer remains associated with a poor prognosis. Sirtuin 1 (SIRT1) was identified to be abnormally upregulated in liver cancer. Dysregulation of microRNAs (miRs/miRNAs) is associated with a variety of types of cancer, and miRNAs may also serve a role in tumorigenesis and progression. The present study demonstrated that following the selection of the cisplatin chemoresistant HepG2 cell line, miR-29c is downregulated using reverse transcription-quantitative polymerase chain reaction. Furthermore, overexpression of miR-29c in cisplatin-resistant cancer cells was demonstrated to inhibit tumor cell proliferation and to promote apoptosis in vitro and in vivo, as well as restoring cisplatin chemosensitivity by using a cell counting assay, colony formation assay, Annexin V-fluorescein isothocyanate/propidium iodide apoptosis analysis, terminal deoxynucleotidyl transferase dUTP nick end labeling and xenograft tumors in nude mice. Mechanistically, according to bioinformatics analysis and a luciferase assay, miR-29c may directly target SIRT1 mRNA and repress SIRT1 expression, which is positively associated with the chemoresistance of liver cancer and may ultimately provide a novel therapeutic method.

BC-02 eradicates liver cancer stem cells by upregulating the ROS-dependent DNA damage.

Cancer stem cells (CSCs) are responsible for chemoresistance, tumor recurrence and metastasis. Reportedly, aminopeptidase N (APN, also known as CD13) is a marker for semi-quiescent CSCs and a therapeutic target in human liver CSCs. In the present study, the effect of BC-02, a compound obtained by conjugating a CD13 inhibitor bestatin and fluorouracil (5-FU), was investigated toward liver CSCs. Tumor spheres formed in serum-free culture conditions have been successfully used to enrich CSCs. In this study, the sphere cells were shown to have several characteristics of CSCs, including drug resistance, high tumorigenicity, epithelial-mesenchymal transition (EMT) phenotype, lower reactive oxygen species (ROS) levels, greater colony-forming efficiency and increased proliferation capacity invitro. Furthermore, BC-02 effectively suppressed self-renewal and malignant proliferation of CSCs compared with 5-FU, bestatin, and even the combination of 5-FU and bestatin. In addition, cell proliferation was effectively suppressed when exposed to 5-FU plus CD13-neutralizing antibody (CD13 Ab) compared with 5-FU alone. BC-02 can effectively inhibit the activity of CD13. Results demonstrated that CD13 inhibitor BC-02 impaired the properties of liver CSCs by targeting CD13 and upregulating the intracellular ROS and ROS-induced DNA damage. BC-02 might be a potential therapeutic agent for eradicating the liver CSCs and overcoming chemoresistance in liver cancer.

Further understanding of mechanisms involved in liver cancer chemoresistance

Further understanding of mechanisms involved in liver cancer chemoresistance

Copy number gain of granulin-epithelin precursor (GEP) at chromosome 17q21 associates with overexpression in human liver cancer.

BackgroundGranulin-epithelin precursor (GEP), a secretory growth factor, demonstrated overexpression in various human cancers, however, mechanism remain elusive. Primary liver cancer, hepatocellular carcinoma (HCC), ranks the second in cancer-related death globally. GEP controlled growth, invasion, metastasis and chemo-resistance in liver cancer. Noted that GEP gene locates at 17q21 and the region has been frequently reported to be amplified in subset of HCC. The study aims to investigate if copy number gain would associate with GEP overexpression.MethodsQuantitative Microsatellite Analysis (QuMA) was used to quantify the GEP DNA copy number, and fluorescent in situ hybridization (FISH) was performed to consolidate the amplification status. GEP gene copy number, mRNA expression level and clinico-pathological features were analyzed.ResultsGEP DNA copy number determined by QuMA corroborated well with the FISH data, and the gene copy number correlated with the expression levels (n = 60, r = 0.331, P = 0.010). Gain of GEP copy number was observed in 20% (12/60) HCC and associated with hepatitis B virus infection status (P = 0.015). In HCC with increased GEP copy number, tight association between GEP DNA and mRNA levels were observed (n = 12, r = 0.664, P = 0.019).ConclusionsGain of the GEP gene copy number was observed in 20% HCC and the frequency comparable to literatures reported on the chromosome region 17q. Increased gene copy number contributed to GEP overexpression in subset of HCC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1294-x) contains supplementary material, which is available to authorized users.

Cyclin G1 Expands Liver Tumor-Initiating Cells by Sox2 Induction via Akt/mTOR Signaling

Recurrence and chemoresistance of liver cancer has been attributed to the existence of liver tumor-initiating cells (T-ICs). It is important to decipher the molecular mechanism for acquisition of drug resistance and to design combinatorial therapeutic strategies. Cyclin G1 has been shown to play a pivotal role in initiation and metastasis of hepatocellular carcinoma. In this study, we found that enhanced cyclin G1 expression was associated with drug resistance of hepatoma cells and higher recurrence rate in hepatocellular carcinoma patients. Expression of cyclin G1 was elevated in liver T-ICs and closely correlated with the expression of liver T-IC markers. Forced cyclin G1 expression remarkably enhanced self-renewal and tumorigenicity of hepatoma cells. Cyclin G1 overexpression dramatically upregulated the expression of Sox2 both in vitro and in vivo, which was impaired by chemical inhibitors of Akt/mTOR signaling. Furthermore, blockade of Akt/mTOR signaling or interference of Sox2 expression suppressed cyclin G1-enhanced self-renewal, chemoresistance, and tumorigenicity of hepatoma cells, indicating that cyclin G1 expands liver T-ICs through Sox2 induction via Akt/mTOR signaling pathway. These results suggest that cyclin G1-induced liver T-IC expansion contributes to the recurrence and chemoresistance of hepatoma, and cyclin G1 may be a promising biomarker for individualized therapy of hepatocellular carcinoma patients.