gambogic-acid and Liver-Neoplasms

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

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

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

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

It is reported that gambogic acid (GA), the main active compound of gamboge which is a dry resin extracted from Garcinia hanburyi tree, has potent antitumor activity both in vivo and in vitro. Activation of mitochondrial apoptotic pathway in cancer cells is one effective therapy for cancer treatment. In the present study, we focus on the effect of GA on induction of reactive oxygen species (ROS) accumulation and triggering the mitochondrial signaling pathway in human hepatoma SMMC-7721 cells. The results indicated that GA induced ROS accumulation and collapse of mitochondrial membrane potential in SMMC-7721 cells in a concentration-dependent manner and subsequently induced that release of Cytochrome c and apoptosis-inducing factor from mitochondria to cytosol, which inhibited ATP generation and induced apoptosis in the cells. Moreover, GA elevated the phosphorylation of c-Jun-N-terminal protein kinase (JNK) and p38, which was the downstream effect of ROS accumulation. Furthermore, N-acetylcysteine, a ROS production inhibitor, partly reversed the activation of JNK and p38 and the induction of apoptosis in GA-treated cells. Collectively, our study demonstrated that accumulation of ROS played an important role in GA-induced mitochondrial signaling pathway, which provided further theoretical support for the application of GA as a promising anticancer agent.

Topics: Acetylcysteine; Adenosine Triphosphate; Antineoplastic Agents, Phytogenic; Apoptosis; Apoptosis Inducing Factor; Blotting, Western; Cell Line, Tumor; Cell Survival; Cytochromes c; Flow Cytometry; Free Radical Scavengers; Glutathione; Humans; JNK Mitogen-Activated Protein Kinases; Liver Neoplasms; Membrane Potential, Mitochondrial; Microscopy, Confocal; Mitochondria, Liver; p38 Mitogen-Activated Protein Kinases; Reactive Oxygen Species; Signal Transduction; 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

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