gambogic-acid and Carcinoma--Hepatocellular

The synergy of chemotherapy and antiangiogenesis therapy is a new strategy for cancer treatment. In this paper, a well-developed core-shell nanoparticle loaded with gambogic acid (GA), heparin (HP), and the immunoadjuvant cytosine-phosphate-guanine oligonucleotide (CpG ODN), called GHC NP, was constructed to treat hepatocellular carcinoma. GHC NPs with liver targeting activity can effectively inhibit tumor cell proliferation and angiogenesis. With the delivery of nanocarriers and the assistance of GA and HP, the GHC NPs can more effectively upregulate cytotoxic T cell (CTL) levels, promote helper T cell (Th cell) differentiation, and induce Th1 immune responses in long-term treatment compared with single CpG ODN. This synergistically enhanced immunotherapy might have universal application in cancer treatments.

Topics: Adjuvants, Immunologic; Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Hepatocellular; Cell Proliferation; Drug Synergism; Hep G2 Cells; Heparin; Humans; Immunotherapy; Liver Neoplasms; Liver Neoplasms, Experimental; Mice; Microscopy, Electron, Transmission; Nanoparticles; Neovascularization, Pathologic; Oligodeoxyribonucleotides; RAW 264.7 Cells; T-Lymphocytes, Cytotoxic; Xanthones

Gambogic acid (GA) is a potential anti-cancer agent with poor water-solubility, whereas heparin has anti-angiogenesis effects with good hydrophilicity. In this study, GA grafted low molecular weight heparin (GA-LMWH) was prepared and self-assembled into micelles in aqueous solution to improve the solubility and antitumor effects against hepatocellular carcinoma. The substitution of GA-LMWH is 27.5±0.2%. The micelles had a mean size of 190.4±10.8nm, a low critical micelle concentration of 2.4±0.2μgmL

Topics: Administration, Intravenous; Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Drug Carriers; Drug Delivery Systems; Heparin, Low-Molecular-Weight; Liver Function Tests; Liver Neoplasms, Experimental; Male; Mice; Micelles; Particle Size; Structure-Activity Relationship; Survival Analysis; Tissue Distribution; Xanthones

Hepatocellular carcinoma (HCC) is one of the most malignant and frequent cancers with a high metastatic potential. The prevention of HCC metastasis is a critical target for effective therapies in HCC. Gambogic acid (GA), a natural compound obtained from Garcinia hanburyi has reported anticancer activity in cell lines. However, the antimetastatic mechanisms of GA are unclear, particularly with respect to HCC. In this study, the influence of GA on migration and invasion of SK-HEP1 cells was evaluated. At concentrations above 0.6 μM, GA reduced cell proliferation in SK-HEP1 cells without affecting proliferation of noncancerous HEK-293 cells. GA also suppressed migration and invasion of SK-HEP1 cells. GA downregulated the expression of the integrin β1/rho family GTPase signaling pathway, suppressed the actin rearrangement related to cell cytoskeleton and migration and decreased matrix metalloproteinases MMP-2, MMP-9, and NF-κB expression involved in cancer invasion. These results suggest that GA may be a potential lead in developing an antimetastatic therapeutic for the treatment of HCC.

Topics: Actin Cytoskeleton; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Movement; Cell Survival; Dose-Response Relationship, Drug; HEK293 Cells; Humans; Liver Neoplasms; Neoplasm Invasiveness; NF-kappa B; Xanthones

The thioredoxin reductase (TrxR) isoenzymes, TrxR1 in cytosol or nucleus and TrxR2 in mitochondria, are essential mammalian selenocysteine (Sec)-containing flavoenzymes with a unique C-terminal -Gly-Cys-Sec-Gly active site. TrxRs are often overexpressed in a number of human tumors, and the reduction of their expression in malignant cells reverses tumor growth, making the enzymes attractive targets for anticancer drug development. Gambogic acid (GA), a natural product that has been used in traditional Chinese medicine for centuries, demonstrates potent anticancer activity in numerous types of human cancer cells and has entered phase II clinical trials. We discovered that GA may interact with TrxR1 to elicit oxidative stress and eventually induce apoptosis in human hepatocellular carcinoma SMMC-7721 cells. GA primarily targets the Sec residue in the antioxidant enzyme TrxR1 to inhibit its Trx-reduction activity, leading to accumulation of reactive oxygen species and collapse of the intracellular redox balance. Importantly, overexpression of functional TrxR1 in cells attenuates the cytotoxicity of GA, whereas knockdown of TrxR1 sensitizes cells to GA. Targeting of TrxR1 by GA thus discloses a previously unrecognized mechanism underlying the biological action of GA and provides useful information for further development of GA as a potential agent in the treatment of cancer.

Topics: Animals; Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cytosol; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Medicine, Chinese Traditional; Molecular Targeted Therapy; Oxidative Stress; Reactive Oxygen Species; Thioredoxin Reductase 1; Xanthones

This study aims to assess the targeted effect and antitumor efficacy of Gambogic-acid-loaded particles (GA-Ps). GA-Ps with uniform particle sizes of 69.8 ± 17.8 nm (GA-P1), 185.6 ± 33.8 nm (GA-P2), 357.8 ± 81.5 nm (GA-P3), and 7.56 ± 0.95 μm (GA-P4) were prepared using an electrospray technique and exhibited extremely high entrapment efficiency. As the particle size increased from the nano- to microscale, the in vitro GA release rate sharply decreased. After tail-vein injection in mice, GA-P samples GA-P1, GA-P2, GA-P3, and GA-P4 improved the uptake of GA 1.67-times in the liver, 1.78-times in the liver, 2.18-times in the spleen, and 2.35-times in the lung, respectively, compared with GA solution (GA-S). The antitumor efficacy of GA-P2, with an 82.51% targeting efficiency (Te) for the liver, was examined in hepatocellular carcinoma (HCC) model mice. After 2 weeks of administration, HCC mice in the GA-P2 group exhibited a lower degree of tumor invasion and cell lesions in hepatic tissue, recovered liver function, and significantly prolonged survival time, compared with mice in the model, GA-S, and normal saline (NS) groups. Pharmacokinetic studies indicated that the superior antitumor efficacy of GA-P2 was attributed not only to tissue targeting but also to low clearance, extended retention, high bioavailability in plasma, and increased GA stability.

Topics: Animals; Carcinoma, Hepatocellular; Cell Survival; Drug Liberation; Liver Neoplasms, Experimental; Male; Mice; Micelles; Nanoparticles; Rats; Rats, Sprague-Dawley; Tissue Distribution; Xanthones

The anticancer activities of gambogic acid (GA) on two hepatocellular carcinoma cells with either p53 deletion (Hep3B) or p53 mutation (Huh7) were investigated in the present study. GA inhibited the growth of Hep3B and Huh7 through similar apoptotic pathways. After treatment of Hep3B and Huh7 with GA for 24 h, the IC₅₀ was determined for both cell lines at 1.8 and 2.2 µM, respectively. The results showed that both cancer cells underwent morphological changes and DNA fragmentation. GA induced apoptosis in the two cell lines through caspases-3/7, -8 and -9 in the mitochondrial pathway. The results suggest that both the caspases in the extrinsic death receptor pathway and the mitochondrial-dependent pathway are involved in the GA-induced cell apoptosis. The inhibitory effects of GA on Hep3B and Huh7 are independent of p53-associated pathway.

Topics: Apoptosis; bcl-2-Associated X Protein; Carcinoma, Hepatocellular; Caspase 8; Cell Line, Tumor; Cell Proliferation; Cytochromes c; DNA Fragmentation; Garcinia; Humans; Liver Neoplasms; Mitochondria; Plant Extracts; Signal Transduction; Tumor Suppressor Protein p53; Xanthones

Gambogic acid (GA), a natural xanthone, has a wide spectrum of pharmacological activities, including repression of telomerase expression and induction of apoptosis of cancer cells. GA has also been reported to reduce the steady-state level of thymidylate synthetase mRNA in a gastric carcinoma cell line. Therefore, it has recently emerged as a candidate for use in cancer treatment. Using hepatoma cells with a dihydrofolate reductase (DHFR) gene amplification and cells transfected with an inducible DHFR transgene, we observed a negative relationship between DHFR expression and resistance to GA. Furthermore, DHFR assays in vitro indicated that in the presence of GA, DHFR activity was slightly inhibited and the affinity of the enzyme for dihydrofolate was markedly decreased. Treatment of rat hepatoma and other human and murine cancer cell lines with methotrexate and GA revealed that the two drugs displayed a marked synergistic lethal effect.

Topics: Animals; Carcinoma, Hepatocellular; Cell Death; Drug Resistance, Neoplasm; Drug Synergism; Folic Acid Antagonists; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Liver Neoplasms; Melanoma, Experimental; Methotrexate; Mice; Pancreatic Neoplasms; Rats; Tetrahydrofolate Dehydrogenase; Xanthones

A series of novel derivatives of gambogic acid (GA) were synthesized and evaluated for their in vitro cytotoxicity against human hepatocellular carcinoma (HCC) cells. All derivatives showed better aqueous solubility than GA, and compounds 3a, 3e, and 3f displayed potent inhibition of HCC cell proliferation (IC(50): 0.045-0.59 μM on Bel-7402 cells and 0.067-0.94 μM on HepG2 cells) superior to GA and taxol. Additionally, the most potent compound 3e did not affect significantly the proliferation of non-tumor liver cells, suggesting that it might selectively inhibit HCC proliferation. Furthermore, 3e induced high frequency of Bel-7402 cell apoptosis. Our findings suggest that these novel GA derivatives may hold a great promise as therapeutic agents for the intervention of human HCC.

Topics: Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Chemistry, Pharmaceutical; Dose-Response Relationship, Drug; Drug Design; Drug Screening Assays, Antitumor; Hep G2 Cells; Humans; Inhibitory Concentration 50; Liver Neoplasms; Models, Chemical; Solubility; Xanthones

Caged 4-oxa-tricyclo[4.3.1.0(3,7)]dec-2-one structural motifs are found in Garcinia natural products that demonstrate anti-tumor activity. Gambogic acid (GA, 1), the most abundant caged Garcinia xanthones, has been reported to be a promising anti-cancer agent. To identify the essential pharmacophore for its anti-tumor activity, a series of GA analogues that address potential key structural features for biological activity were synthesized, among which compound 11a displayed comparable in vitro anti-tumor activity as GA. Mechanistic studies on 11a determined that the compound induces apoptosis as well as arrests the G2/M phase of the cell cycle in HepG2 cells. The determination of the essential part of the scaffold found in GA to maintain anti-tumor effects, and the SAR based on the caged pharmacophore are reported and will provide key information for future anti-cancer drug development studies.

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Biological Products; Carcinoma, Hepatocellular; Caspase 3; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Humans; Mice; Proto-Oncogene Proteins c-bcl-2; Structure-Activity Relationship; Xanthones; Xenograft Model Antitumor Assays

The objective of this study was to investigate the apoptosis-inducing effect of an oxidative analogue of gambogic acid (GA) on the human hepatocellular carcinoma cell line HepG2 and explore the related molecular mechanisms. HepG2 cells were treated with the analogue of GA and the growth inhibition was analysed by MTT assay. The morphological changes in cells were observed under an inverted light microscope and a fluorescence microscope. In addition, both the cell-cycle arrest and the apoptosis rate were detected by flow cytometry. Western blot was used to evaluate the alteration of protein expression. The viability of HepG2 cells was markedly inhibited in a concentration-dependent manner and obvious morphological changes were confirmed, including condensed chromatin and reduced volume. Increased percentage of apoptotic cells was displayed and altered expression level of several apoptosis-associated proteins, P53, Bcl-2, Bax and pro-caspase-3, was obtained. The newly synthesized analogue of GA exhibited potential anticancer activity, induced remarkable apoptosis in HepG2 cells, probably through the intrinsic mitochondrial pathway, and promised to be a new candidate for future cancer therapy.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Carcinoma, Hepatocellular; Cell Cycle; Cell Line, Tumor; Cell Shape; Cell Survival; Drug Evaluation, Preclinical; Humans; Liver Neoplasms; Models, Biological; Oxidation-Reduction; Xanthones

Gamboge has been developed as an injectable drug for cancer treatment in China. In this study, the inhibition ratio and their IC(50) values of two derivatives from Gamboge in hepatocellular carcinoma (HCC) were determined. Proteomic approach was employed to reveal the target proteins of these two derivatives, gambogic acid (GA), and gambogenic acid (GEA). HCC cells were cultured under varied conditions with the addition of either GA or GEA. Twenty differentially expressed proteins were identified and the four most distinctly expressed proteins were further validated by Western blotting. GA and GEA revealed inhibitory effects on HCC cell proliferation. The expression of cyclin-dependent kinase 4 inhibitor A and guanine nucleotide-binding protein beta subunit 1 were upregulated by both xanthones, whilst the expression of 14-3-3 protein sigma and stathmin 1 (STMN1) were downregulated. Furthermore, overexpression of STMN1 in HCC cells decreased their sensitivity, whilst small interfering RNAs targeting STMN1 enhanced their sensitivity to GA and GEA. In conclusion, our study suggested for the first time that STMN1 might be a major target for GA and GEA in combating HCC. Further investigation may lead to a new generation of anticancer drugs exerting synergistic effect with conventional therapy, thus to promote treatment efficacy.

Topics: Blotting, Western; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase 4; Gene Expression; GTP-Binding Protein beta Subunits; Humans; Inhibitory Concentration 50; Proteomics; RNA, Small Interfering; Stathmin; Xanthones

Gambogic acid (GA) is the major active ingredient of gamboge, a brownish resin exuded from Garcinia hanburryi tree in Southeast Asia. In this study, we compared the different apoptotic induction of GA on human normal embryonic hepatic L02 cells and human hepatoma SMMC-7721 cells by detecting growth inhibition, observing morphological changes, and the expressions of the relative apoptotic proteins (Bax, Bcl-2 and caspase-3). The results indicated that GA could selectively induce apoptosis of SMMC-7721 cells, while had relatively less effect on L02 cells. To illustrate the distinct selective antitumor mechanism of GA, we further study its distribution in cultured cells and in tumor-bearing mice. The results indicated that SMMC-7721 cells have higher GA binding activity than L02 cells. The retention time of GA in grafted tumor was longer than in liver, renal and other organs. Collectively, the selective anticancer activity of GA could be due to its significant apoptotic inducing effects as well as its higher distribution and longer retention time in tumor cells compared to the normal cells. So GA might be a kind of highly effective anticancer drug candidate with low toxicity to normal tissue.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Carcinoma, Hepatocellular; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cell Shape; Cells, Cultured; Dose-Response Relationship, Drug; Female; Hepatocytes; Humans; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Xanthones; Xenograft Model Antitumor Assays

The activation of human telomerase, a process regulated by the human telomerase reverse transcriptase (hTERT), is a crucial step during cellular immortalization and malignant transformation. We have reported that gambogic acid (GA), a natural product isolated from the gamboge resin of Garcinia hanburyi tree, is an effective telomerase inhibitor and thus displays potent anticancer activity both in vitro and in vivo. Here we present the direct interaction of GA with oncogene c-MYC, a ubiquitous transcription factor involved in the control of cell proliferation and differentiation, as the molecular mechanism of GA's inhibitory effect on telomerase activity. Consistent with the recently reported association between c-MYC overexpression and induction of telomerase activity, we find here that GA treatment of a human hepatoma cell line SMMC-7721 significantly reduced the expression of c-MYC in a time- and concentration-dependent manner accompanied with the down-regulation of the hTERT transcription and the ultimate reduction in telomerase activity. Our results indicate that the hTERT is a target of c-MYC activity and identify a feasible mechanism of GA's potent anticancer activity.

Topics: Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; DNA-Binding Proteins; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Gene Expression Regulation, Enzymologic; Humans; Proto-Oncogene Proteins c-myc; Telomerase; Xanthones

To study the inhibitory effect of general gambogic acids (GGA) on transplantation tumor SMMC-7721 in experimental animal model and SMMC-7721 cells in vitro.. Anti-tumor activity of GGA in the experimental transplantation tumor SMMC-7721 was evaluated by relative tumor growth ratio. Cell morphology was observed with inverted microscope and electron microscope. Cell proliferation was measured by MTT assay and the telomerase activity was determined by PCR.. In vivo study indicated that GGA (2, 4, and 8 mg/kg, iv, 3 times per week for 3 weeks) displayed an inhibitory effect on the growth of transplantation tumor SMMC-7721 in nude mice compared with the normal saline group (P<0.01). At the concentrations of 0.625-5.0 mg/L, GGA remarkably inhibited the proliferation of SMMC-7721 cells in vitro. GGA 2 mg/L dramatically changed morphology of SMMC-7721 cells and inhibited the telomerase activity in SMMC-7721 cells.. GGA had inhibitory effect on the growth of SMMC-7721, which might be related to its inhibition of telomerase activity.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Cell Division; Cell Line, Tumor; Female; Garcinia; Humans; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Plants, Medicinal; Telomerase; Xanthones