Gambogenic acid alters chemosensitivity of breast cancer cells to Adriamycin

Synergistic and mechanistic effects of neogambogic acid in enhancing almonertinib sensitivity in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is characterized by a complex pathogenesis and high mortality. Targeted drug therapy represents a precise method of treatment. However, Improving sensitivity to targeted agents is currently a major challenge in clinical tumor therapy. Neogambogic acid (NGA), a bioactive compound isolated from the Traditional Chinese Medicine (TCM) Gamboge, has shown potential in NSCLC treatment. Nonetheless, the mechanism by which NGA enhances the sensitivity of NSCLC to the targeted drug Almonertinib remains unclear. This study aimed to elucidate the mechanisms underlying the ability of NGA to enhance the sensitivity of NSCLC to Almonertinib, revealing the synergistic effect exerted by the combination therapy. We established a subcutaneous grafted tumor model of mouse lung cancer by injecting Lewis cells, and evaluated the therapeutic efficacy in vivo. The study demonstrated that NGA combined with Almonertinib effectively suppressed NSCLC tumor growth by promoting cancer cell apoptosis and reducing serum tumor marker levels. In vitro experiments revealed that this combination synergistically inhibited lung cancer cell proliferation and induced apoptosis. Mechanistically, NGA demonstrated the ability to bind to Pregnane X receptor (PXR), regulating the expression of drug-metabolizing enzymes and transporters. We further validated this effect using PXR agonists and inhibitors in A549 cells. Additionally, the combination of NGA with Almonertinib significantly inhibited aberrant EGFR activation and downstream PI3K/AKT signaling, leading to enhanced apoptosis. This study demonstrated that the combination of NGA and Almonertinib inhibited the expression of CYP3A4, P-gp, and BCRP via PXR modulation. Meanwhile, it inhibited the EGFR/PI3K/AKT pathway and enhanced the sensitivity of NSCLC to Almonertinib, exerting synergistic anti-tumor effects. Our findings suggest a promising strategy for integrating active TCM components with targeted therapy in NSCLC management.

Zwitterionic polymer-coated magnetic nanoparticle induced chemotherapy and ferroptosis for triple-negative breast cancer therapy

Triple-negative breast cancer (TNBC), an aggressive cancer with a high risk of metastasis and recurrence, is resistant to conventional chemotherapy. Ferroptosis, a non-apoptotic form of cell death, is primarily caused by excessive accumulation of lipid peroxides, and is closely associated with the occurrence and development of various diseases. Mounting evidence indicates that ferroptosis is becoming a promising treatment for TNBC based on its inherent characteristics. Herein, zwitterionic polymer poly (N-(3-sulfopropyl)-N-methacryloxyethyl-N,N-dimethylammonium betaine) (PSBMA)-coated gambogenic acid (GNA)-loaded magnetic composite nanoparticles (Fe3O4@PSBMA-GNA) were fabricated for chemotherapy combined with ferroptosis therapy for TNBC. Fe3O4@PSBMA-GNA achieved significant cytotoxicity against TNBC cell lines and contributed to the disruption of intracellular redox homeostasis. Furthermore, Fe3O4@PSBMA-GNA could induce apoptosis through the inhibition of Bcl-2 and trigger ferroptosis by inhibiting the PI3K/AKT/mTOR/GPX4 pathway in MDA-MB-231 cells simultaneously. Given the excellent blood circulation performance, Fe3O4@PSBMA-GNA enhanced tumor accumulation and showed a satisfactory tumor suppression effect on MDA-MB-231 tumor-bearing mice. This strategy of chemotherapy combined with ferroptosis therapy is expected to be a feasible treatment for refractory TNBC.

Unveiling Gambogenic Acid as a Promising Antitumor Compound: A Review

Gambogenic acid is a derivative of gambogic acid, a polyprenylated xanthone isolated from Garcinia hanburyi. Compared with the more widely studied gambogic acid, gambogenic acid has demonstrated advantages such as a more potent antitumor effect and less systemic toxicity than gambogic acid according to early investigations. Therefore, the present review summarizes the effectiveness and mechanisms of gambogenic acid in different cancers and highlights the mechanisms of action. In addition, drug delivery systems to improve the bioavailability of gambogenic acid and its pharmacokinetic profile are included. Gambogenic acid has been applied to treat a wide range of cancers, such as lung, liver, colorectal, breast, gastric, bladder, and prostate cancers. Gambogenic acid exerts its antitumor effects as a novel class of enhancer of zeste homolog 2 inhibitors. It prevents cancer cell proliferation by inducing apoptosis, ferroptosis, and necroptosis and controlling the cell cycle as well as autophagy. Gambogenic acid also hinders tumor cell invasion and metastasis by downregulating metastasis-related proteins. Moreover, gambogenic acid increases the sensitivity of cancer cells to chemotherapy and has shown effects on multidrug resistance in malignancy. This review adds insights for the prevention and treatment of cancers using gambogenic acid.

Synergistic antitumor effects of Peiminine and Doxorubicin on breast cancer through enhancing DNA damage via ZEB1

Peiminine, the primary biologically active compound from Fritillaria thunbergii Miq., has demonstrated significant pharmacological activities. Doxorubicin is one of the most potent chemotherapeutic agents for breast cancer (BC). This study was designed to investigate the efficacy and underlying mechanisms of Peiminine combined with Doxorubicin in treating BC. Our results demonstrated that the combination of Peiminine and 1 mg/kg Doxorubicin exhibited more significant suppression of tumor growth compared with the monotherapy in MDA-MB-231 xenograft nude mice model, which is comparable to the effect of 3 mg/kg Doxorubicin in vivo. Notably, the 3 mg/kg Doxorubicin monotherapy resulted in organ toxicity, specifically in the liver and heart, whereas no toxicity was observed in the combination group. In vitro, this combined treatment exhibited a synergistic reduction on the viability of BC cells. Peiminine enhanced the cell cycle arrest and DNA damage induced by Doxorubicin. Furthermore, the combination treatment effectively blocked DNA repair by inhibiting the MAPKs signaling pathways. And ZEB1 knockdown attenuated the combined effect of Peiminine and Doxorubicin on cell viability and DNA damage. In conclusion, our study found that the combination of Peiminine and Doxorubicin showed synergistic inhibitory effects on BC both in vivo and in vitro through enhancing Doxorubicin-induced DNA damage. These findings support that their combination is a novel and promising therapeutic strategy for treating BC.

Gambogenic acid alleviates kidney fibrosis via epigenetic inhibition of EZH2 to regulate Smad7-dependent mechanism

BACKGROUND

Epigenetics regulating gene expression plays important role in kidney fibrosis. Natural products originating from diverse sources including plants and microorganisms are capable to influence epigenetic modifications. Gambogenic acid (GNA) is a caged xanthone extracted from gamboge resin, exudation of Garcinia hanburyi Hook.f., and the effect of GNA on kidney fibrosis with its underlying mechanism on epigenetics remains unknown.

PURPOSE

This study aimed to explore the role of GNA against kidney fibrogenesis by histone methylation mediating gene expression.

METHODS

Two experimental mice of unilateral ureteral obstruction (UUO) and folic acid (FA) were given two dosages of GNA (3 and 6 mg/kg/d). TGF-β1 was used to stimulate mouse tubular epithelial (TCMK-1) cells and siRNAs were transfected to verify the underlying mechanisms of GNA. Histological changes were evaluated by HE, MASSON stainings, immunohistochemistry and immunofluorescence. Western blot and qPCR were used to measure protein/gene transcription levels.

RESULTS

GNA dose-dependently alleviated UUO-induced kidney fibrosis and FA-induced kidney early fibrosis, indicated by the pathology and fibrotic factor changes (α-SMA, collagen I, collagen VI, and fibronectin). Mechanically, GNA reduced enhancer of zeste homolog 2 (EZH2) and H3K27me3, promoted Smad7 transcription, and inhibited TGF-β/Smad3 fibrotic signaling in injured kidneys. Moreover, with TGF-β1-induced EZH2 increasing, GNA suppressed α-SMA, fibronectin and collagen levels in tubular epithelial TCMK-1 cells. Although partially decreasing EZH2, GNA did not influence fibrotic signaling in Smad7 siRNA-transfected TCMK-1 cells.

CONCLUSION

Epigenetic inhibition of EZH2 by GNA ameliorated kidney fibrogenesis via regulating Smad7-meidated TGF-β/Smad3 signaling.

Meta analysis of bioactive compounds, miRNA, siRNA and cell death regulators as sensitizers to doxorubicin induced chemoresistance

Cancer has presented to be the most challenging disease, contributing to one in six mortalities worldwide. The current treatment regimen involves multiple rounds of chemotherapy administration, alone or in combination. The treatment has adverse effects including cardiomyopathy, hepatotoxicity, and nephrotoxicity. In addition, the development of resistance to chemo has been attributed to cancer relapse and low patient overall survivability. Multiple drug resistance development may be through numerous factors such as up-regulation of drug transporters, drug inactivation, alteration of drug targets and drug degradation. Doxorubicin is a widely used first line chemotherapeutic drug for a myriad of cancers. It has multiple intracellular targets, DNA intercalation, adduct formation, topoisomerase inhibition, iron chelation, reactive oxygen species generation and promotes immune mediated clearance of the tumor. Agents that can sensitize the resistant cancer cells to the chemotherapeutic drug are currently the focus to improve the clinical efficiency of cancer therapy. This review summarizes the recent 10-year research on the use of natural phytochemicals, inhibitors of apoptosis and autophagy, miRNAs, siRNAs and nanoformulations being investigated for doxorubicin chemosensitization.

Gambogenic Acid Inhibits Basal Autophagy of Drug-Resistant Hepatoma Cells and Improves Its Sensitivity to Adriamycin

Gambogenic acid (GNA) is extracted from plant Gamboge, has a wide range of anti-tumor effects. In this paper, we study the inhibitory effect of GNA on the BEL-7402/ADM of hepatoma resistant cell lines and further study the mechanism of action. Cell viability test represented that GNA could improve the sensitivity of hepatoma drug-resistant cell line BEL-7402/ADM to Adriamycin (ADM), and further study by 4',6-diamidino-2-phenylindole (DAPI) staining and flow cytometry found that GNA could improve the effect of ADM on promoting apoptosis in BEL-7402/ADM cells, and the activation of apoptosis-related protein was significantly increased, and the ratio of Bax to Bcl-2 was significantly increased. Monodansylcadaverine staining and transmission electron microscopy showed that the basal autophagy level of BEL-7402/ADM cells was higher than that of BEL-7402 cells. Further detection of protein expression found that the intracellular LC3-II to LC3-I ratio and Beclin 1 protein expression increased in the combination of GNA and ADM, but the protein level of p62 increased significantly. GNA inhibit protective autophagy in BEL-7402/ADM cells and promote the role of ADM in inducing apoptosis, thereby increasing ADM sensitivity to BEL-7402/ADM cells, and the effect of GNA inhibition of autophagy may be achieved by inhibiting the degradation of autophagosomes.

Gambogenic Acid Induces Endoplasmic Reticulum Stress in Colorectal Cancer via the Aurora A Pathway

Colorectal cancer (CRC) is one of the most common malignancies in the world and has a poor prognosis. In the present research, gambogenic acid (GNA), isolated from the traditional Chinese medicine gamboge, markedly induced apoptosis and inhibited the proliferation of CRC in vitro and in vivo. Furthermore, GNA triggered endoplasmic reticulum (ER) stress, which subsequently activated inositol-requiring enzyme (IRE) 1α and the eukaryotic translation initiation factor (eIF) 2α pathway. Pretreatment with salubrinal (an eIF2α inhibitor) rescued GNA-induced cell death. Furthermore, GNA downregulated the expression of Aurora A. The Aurora A inhibitor alisertib decreased ER stress. In human colorectal adenocarcinoma tissue, Aurora A was upregulated compared to normal colorectal epithelial nuclei. Furthermore, GNA ameliorated mouse colitis-associated cancer models. Our findings demonstrated that GNA significantly inhibited the proliferation of CRC through activation of ER stress by regulating Aurora A, which indicates the potential of GNA for preventing the progression of CRC.

Traditional Chinese medicine reverses cancer multidrug resistance and its mechanism

Chemotherapy is one of the most commonly used clinical treatments among the currently available cancer therapies. However, the phenomenon of Multidrug resistance (MDR) has become a challenge in the treatment process, weakening the impact of chemotherapy. Extensive research on elucidating the development of cancer MDR has identified the following mechanisms that play a critical role in the development of several MDR reversal agents: abnormal expression of cell membrane transporters, adaptation of cancer cells to the microenvironment, regulation of hypoxia, repair of DNA damage and reduction of apoptosis, the enhancement of the EMT process, the existence of cancer stem cells (CSCs), and the abnormal activation of key signaling pathways. However, they failed to demonstrate significant efficacy due to severe side effects during their clinical trials. Traditional Chinese medicines (TCMs) are known to play an important anti-cancer role since they have low toxicity, high efficacy, and safety and can reverse MDR. TCMs reversal agents can be divided into Chinese medicine monomers, synthetic monomers, analogs, or derivatives. Several studies have shown that TCMs can effectively overcome cancer MDR and can be effectively used for treating cancer patients.

Role of gambogenic acid in regulating PI3K/Akt/NF-kβ signaling pathways in rat model of acute hepatotoxicity

The purpose of this study is to investigate the protective effect of gambogenic acid (GA) in acetaminophen (APAP)-induced hepatotoxicity in rat models. GA (10 mg/kg) was administered intraperitoneal (i.p.) to rats for 7 consecutive days followed by APAP (500 mg/kg) single dose (i.p.) on the final day after GA administration. The levels of MDA, GSH, SOD, CAT, GPx, GST, ALP, AST, ALT, proinflammatory cytokines (TNF-α, IL-1β, IL-6), apoptosis markers (caspase-3 and -9, Bax, Bcl-2), 4-hydroxynonenal (4-HNE), and prostaglandin E2 (PGE2) were evaluated. Results exhibited protective effects of GA by inhibiting inflammation, preventing oxidative stress and apoptosis in APAP-induced liver. Histopathological changes caused by APAP were attenuated, protein expressions of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) were upregulated, and nuclear factor-kappa β (NF-kβ) was downregulated by GA. In summary, GA significantly exerted anti-inflammatory and antiapoptotic effects against APAP-induced hepatotoxicity potentially through regulation of PI3K/Akt and NF-kβ signaling pathways.

Oral Delivery of Gambogenic Acid by Functional Polydopamine Nanoparticles for Targeted Tumor Therapy

To enhance the water solubility, oral bioavailability, and tumor targeting of gambogenic acid (GNA), polydopamine nanoparticles (PDA NPs) were prepared to encapsulate and stabilize GNA surface modified by folic acid (FA) and then coated with sodium alginate (GNA@PDA-FA SA NPs) to achieve an antitumor effect by oral administration. GNA@PDA-FA SA NPs exhibited in vitro pH-sensitive release behavior. In vitro cell studies manifested that GNA@PDA-FA NPs had higher cytotoxicity to 4T1 cells compared with raw GNA (IC₅₀ = 2.58 μM vs 7.57 μM). After being modified with FA, GNA@PDA-FA NPs were taken up easily by 4T1 cells. In vivo studies demonstrated that the area under the curve (AUC_0→∞) of the plasma drug concentration-time of GNA@PDA-FA SA NPs was 2.97-fold higher than that of raw GNA, along with improving drug distribution in the liver, lung, and kidney tissues. In vivo anti-tumor experiments, GNA@PDA-FA SA NPs significantly inhibited the growth of breast tumors in the 4T1 xenograft breast cancer model via oral administration without obvious toxicity on major organs. Our studies indicated that the GNA@PDA-FA SA NPs modified with FA and coated with SA were a promising drug delivery system for targeting tumor therapy via oral administration.

In vitro/in vivo evaluation of pH-sensitive Gambogenic acid loaded Zein nanoparticles with polydopamine coating

As one of the active pharmaceutical ingredients in Gamboge, Gambogenic acid (GNA) has shown diverse anti-tumor activities. To reduce the vascular irritation of GNA and improve its water solubility, tumor targeting, and bioavailability, GNA loaded Zein nanoparticles (GNA@Zein NPs) was further coated by polydopamine (PDA) to develop GNA@Zein-PDA NPs by anti-solvent precipitation and surface modification. The results showed that particle size and Zeta potential of GNA@Zein-PDA NPs were about 310 nm and -40.8 mV with core-shell morphology confirmed by TEM. GNA@Zein-PDA NPs increased the water solubility of GNA by more than 700 times and showed pH-sensitive release behavior in PBS with pH 6.86. In vitro cytotoxicity tests showed that GNA@Zein-PDA NPs had higher inhibitory activity on HepG2 cells than free GNA, and their IC₅₀ were 1.59 μg/mL and 9.89 μg/mL, respectively. Additionally, the hemolysis and vascular irritation assay showed that GNA@Zein-PDA NPs had good cytocompatibility and reduced the irritation of GNA to blood vessels. Moreover, the in vivo pharmacokinetic experiments exhibited that the C_max and AUC_0-t of GNA@Zein-PDA NPs were significantly improved approximately by 2.09-fold and 3.48-fold over that of GNA, respectively. In conclusion, GNA@Zein-PDA NPs solve many defects of GNA and provide a tumor-targeting drug delivery for GNA.

Gambogenic acid exerts anticancer effects in cisplatin‑resistant non‑small cell lung cancer cells

Non‑small cell lung cancer (NSCLC) is the most common type of lung cancer and the most common cause of mortality in patients with lung cancer. The efficacy of cisplatin‑based chemotherapy in NSCLC is limited by drug resistance, therefore, the development of novel anticancer agents is required to overcome cisplatin resistance. The present study investigated the anticancer activity of gambogenic acid (GNA), derived from gamboge, in the cisplatin‑resistant NSCLC cell line A549/Cis. GNA was revealed to have a potent inhibitory effect on cell growth in A549/Cis cells by blocking the cell cycle and inducing apoptosis. The investigation of the molecular mechanisms identified that GNA arrested the cell cycle at the G1 phase through the downregulation of cyclin Ds, cyclin dependent kinase (CDK)4 and CDK6, and the upregulation of p53 and p21. In addition, GNA induced apoptosis by increasing the activation of caspase 3 and caspase 7, in addition to the cleavage of poly(ADP‑ribose) polymerase. The results of the present study supported the potential application of GNA in cisplatin‑resistant NSCLC.

Targeting the unfolded protein response in head and neck and oral cavity cancers

Many FDA-approved anti-cancer therapies, targeted toward a wide array of molecular targets and signaling networks, have been demonstrated to activate the unfolded protein response (UPR). Despite a critical role for UPR signaling in the apoptotic execution of cancer cells by many of these compounds, the authors are currently unaware of any instance whereby a cancer drug was developed with the UPR as the intended target. With the essential role of the UPR as a driving force in the genesis and maintenance of the malignant phenotype, a great number of pre-clinical studies have surged into the medical literature describing the ability of dozens of compounds to induce UPR signaling in a myriad of cancer models. The focus of the current work is to review the literature and explore the role of the UPR as a mediator of chemotherapy-induced cell death in squamous cell carcinomas of the head and neck (HNSCC) and oral cavity (OCSCC), with an emphasis on preclinical studies.

MiR-202-5p/PTEN mediates doxorubicin-resistance of breast cancer cells via PI3K/Akt signaling pathway

We intended to explore the effect of miR-202-5p and phosphatase and tensin homolog (PTEN) on doxorubicin (DOX) resistance of breast cancer cells. The result of quantitative reverse transcription-polymerase chain reaction (qRT-PCR) reveals that miR-202-5p was highly expressed in drug-resistant breast cancer tissues, while PTEN was expressed less. MiR-202-5p directly targeted PTEN. Further, it was found that the overexpression of miR-202-5p promoted the DOX resistance and proliferation as well as decreased apoptosis of MCF-7 cells. The lower expression of miR-202-5p inhibited DOX resistance and proliferation as well as increased the apoptosis of MCF-7/DOX cells. In vivo experiments showed that mice with downregulated miR-202-5p had smaller tumor volume and lower Ki67 level. The overexpression of PTEN declined the proliferation of MCF7 cells, while miR-202-5p's overexpression could offset the function of overexpression of PTEN. The knockdown of PTEN promoted MCF7/DOX cell proliferation that could be counteracted by miR-202-5p silence. Moreover, we also revealed that downregulated miR-202-5p expression inhibited PI3k/Akt signaling pathway-related protein by regulating expression of PTEN.

Traditional Chinese medicine-combination therapies utilizing nanotechnology-based targeted delivery systems: a new strategy for antitumor treatment

Cancer is a major public health problem, and is now the world’s leading cause of death. Traditional Chinese medicine (TCM)-combination therapy is a new treatment approach and a vital therapeutic strategy for cancer, as it exhibits promising antitumor potential. Nano-targeted drug-delivery systems have remarkable advantages and allow the development of TCM-combination therapies by systematically controlling drug release and delivering drugs to solid tumors. In this review, the anticancer activity of TCM compounds is introduced. The combined use of TCM for antitumor treatment is analyzed and summarized. These combination therapies, using a single nanocarrier system, namely codelivery, are analyzed, issues that require attention are determined, and future perspectives are identified. We carried out a systematic review of >280 studies published in PubMed since 1985 (no patents involved), in order to provide a few basic considerations in terms of the design principles and management of targeted nanotechnology-based TCM-combination therapies.

Gambogenic acid inhibits fibroblast growth factor receptor signaling pathway in erlotinib-resistant non-small-cell lung cancer and suppresses patient-derived xenograft growth

Erlotinib resistance causes a high degree of lethality in non-small-cell lung cancer (NSCLC) patients. The high expression and activation of several receptor tyrosine kinases, such as JAK/STAT3, c-Met, and EGFR, play important roles in drug resistance. The development of tyrosine kinase inhibitors is urgently required in the clinic. Our previous study found that Gambogenic acid (GNA), a small molecule derived from the traditional Chinese medicine herb gamboge, induced cell death in several NSCLC cell lines through JAK/STAT3 inhibition. In this study, we investigated the mechanism of action of GNA in erlotinib-resistant NSCLC and patient-derived cells. The inhibition of GNA on FGFR signaling pathway was examined using biochemical kinase assays. NSCLC cell lines (HCC827, HCC827-Erlotinib-resistant, and H1650) and primary cells from patients with NSCLC with clinical resistance to erlotinib were treated with GNA, erlotinib, or their combination. Both kinase assays and cell- based assays showed that GNA inhibits the phosphorylation of multiple kinases in FGFR signaling pathway in NSCLC. The combination of GNA and erlotinib significantly attenuates the tumor growth of HCC827 and erlotinib-resistant HCC827 xenografts with low toxicity. Importantly, GNA significantly suppresses tumor growth in a lung patient-derived xenograft (PDX) model with FGFR fusion and low EGFR expression. Our findings provide preclinical evidence for using GNA as an FGFR signaling pathway inhibitor to overcome erlotinib resistance in NSCLC treatment or to enhance erlotinib efficacy when used as a combined administration.

Gambogenic Acid Exerts Antitumor Activity in Hypoxic Multiple Myeloma Cells by Regulation of miR-21

Hypoxia is an inseparable component of the bone marrow (BM) microenvironment, accounting for aggressive tumor behavior and poor prognosis of multiple myeloma (MM). Gambogenic acid (GNA) has proven to be an attractive option for treatment of tumors due to its tumor suppressive activity. Herein, we found that GNA exhibits remarkable apoptotic activity against MM cells even under hypoxia. MicroRNA-21 (miR-21) has been found over-expressed in MM patients and associated with the occurrence and development of MM. Direct studies have shown that there is a functional link between hypoxia and miR-21 expression in multiple types of tumors. In the current study, we found that hypoxia increased miR-21 expression in U266 cells and miR-21 induced by hypoxia was associated with concurrent reductions in its target PTEN. After treatment with GNA, miR-21 expression in hypoxic U266 cells was strikingly downregulated in a dose-dependent manner. Besides, we identified that regulation of miR-21/PTEN by GNA under hypoxia is related with inhibition of HIF-1α accumulation and STAT3 phosphorylation. Furthermore, in vivo study revealed that intravenous GNA injection could significantly suppress tumor growth and the miR-21/PTEN pathway is involved in GNA's anti-tumor effects. Taken together, all these results indicated that GNA could be a highly potent therapeutic for human MM.

Gambogenic acid induces proteasomal degradation of CIP2A and sensitizes hepatocellular carcinoma to anticancer agents

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an oncoprotein that is overexpressed in many human malignancies. It regulates phosphorylated AKT and stabilizes c‑Myc in cell proliferation and tumor formation, suggesting that CIP2A plays an essential role in the development of cancer. In the present study, we report that a natural compound, gambogenic acid (GEA), induced the degradation of CIP2A via the ubiquitin‑proteasome pathway. Interestingly, the combination of GEA and proteasome inhibitors potentiated the accumulation of ubiquitinated CIP2A and aggresome formation. In addition, GEA exhibited an inhibitory effect on cell proliferation and CIP2A‑downstream signaling molecules (c‑Myc and pAKT). Furthermore, GEA and CIP2A silencing enhanced the chemosensitivity of hepatocellular carcinoma cells to anticancer agents, suggesting that a combination of a CIP2A inhibitor and anticancer agents could be a valuable clinical therapeutic strategy. These results indicate that GEA is a CIP2A inhibitor that interferes with the ubiquitination and destabilization of CIP2A, providing a promising strategy to enhance the combinational therapy for hepatocellular carcinoma.