gambogic-acid and Carcinoma--Non-Small-Cell-Lung

Non-small cell lung cancer (NSCLC) is the most frequent type of lung cancer accounting up to 80-85% of all lung cancer (LC) cases. Gemcitabine (Gem), a pyrimidine nucleoside antimetabolite, is widely used chemotherapy offering several months survival benefit in patients with NSCLC. The emergence of Gem resistance is a main clinical concern in cancer treatment and thus a continuous demand for development of new therapeutic strategies to improve its antitumor activity. Hence, we report an adjuvant therapeutic regimen based on natural compound, gambogic acid (GA) which has been shown to enhanced Gem induced inhibition of cancer cell growth, arrest cell cycle, and induce apoptosis by enhanced accumulation of Gem. The in vitro cell viability, clonogenicity, invasion, and migration assays demonstrated a significant higher therapeutic effect of Gem when it was combined with GA in A549 and H1299 cells. A better access of internalization of drug molecules achieved in rhodamine 123 assay when GA was used as adjuvant treatment. Further, GA and Gem combination significantly reduced tubular formation of HUVEC cells indicates lowering angiogenesis potential. Microarray and Western blot studies confirm that GA + Gem co-treatment strategy promotes cancer cell death by downregulating anti-apoptotic proteins, chemoresistance-associated proteins, and upregulation of apoptosis proteins. More importantly, a significant higher therapeutic benefit was noticed for GA and Gem combination in A549 xenograft mice model. Together, these results offer a rationale to evaluate the clinical translational possibility of GA as adjuvant therapy to overcome Gem resistance. This combination regimen can be a new therapeutic concept to eradicate this devastating disease.

Topics: A549 Cells; Adult; Animals; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Non-Small-Cell Lung; Cell Survival; Deoxycytidine; Dose-Response Relationship, Drug; Drug Synergism; Gemcitabine; Humans; Lung Neoplasms; Male; Mice, Nude; Middle Aged; Pilot Projects; Tumor Cells, Cultured; Xanthones; Xenograft Model Antitumor Assays

Liver kinase B1 (LKB1) is a tumor suppressor that functions as master regulator of cell growth, metabolism, survival, and polarity. Patients with NSCLC possessing mutated LKB1 respond to chemotherapy differently from those with wild-type LKB1. Gambogic acid (GA), a small molecule from natural product, has been established as an anti-tumor agent due to its potent activity and low toxicity. Here, we find out that NSCLC cells with wild-type LKB1 are more sensitive to GA in vitro and in vivo. Mechanistic studies pinpoint that the selective inhibition of mTOR signaling confers the stronger suppression of NSCLC in presence of wild-type LKB1, which is involved in the enhancement of p-AMPK. Further studies reveal that GA increases p-AMPK levels through up-regulation of E-cadherin associated with LKB1. In addition, induction of E-cadherin by GA may be through down-regulation of ZEB1, which is independent with LKB1 status. Hence, our findings support that enhanced E-cadherin by GA cooperates LKB1, leading to up-regulation of p-AMPK, and thus blocking of mTOR signaling pathway, which provide theoretical foundation for utilization of GA as a potential targeted drug against NSCLC harboring wild-type LKB1.

Topics: AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Animals; Cadherins; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Female; Humans; Lung Neoplasms; Mice; Mice, Inbred BALB C; Protein Serine-Threonine Kinases; Signal Transduction; TOR Serine-Threonine Kinases; Xanthones

BACKGROUND Gambogic acid (AG) is believed to be a potent anti-cancer agent. ER (endoplasmic reticulum) stress-induced cell apoptosis was identified as one of the anti-proliferative mechanisms of several anti-cancer agents. In this study, we investigated the involvement of ER stress-induced apoptosis in the anti-proliferative effect of GA on NSCLC (non-small cell lung cancer) cells. MATERIAL AND METHODS GA at 0, 0.5, and 1.0 μmol/l was used to treat A549 cells. We also used the ER stress-specific inhibitor 4-PBA (4-phenylbutyric acid) (1 μmol/l) to co-treat the cells incubated with GA. Cell viability was assessed by MTT (methyl thiazolyl tetrazolium) assay. Cell apoptosis was evaluated by MTT (methyl thiazolyl tetrazolium) assay. Intracellular ROS (reactive oxygen species) production was detected by DCFH-DA (2,7- dichloro-dihydrofluorescein diacetate) florescent staining. Western blotting was used to assess the expression and phosphorylation levels of protein. RESULTS GA treatment significantly reduced cell viabilities of NSCLC cells in a concentration-dependent manner. GA treatment increased intracellular ROS level, expression levels of GRP (glucose-regulated protein) 78, CHOP (C/EBP-homologous protein), ATF (activating transcription factor) 6 and caspase 12, as well as the phosphorylation levels of PERK (protein kinase R-like ER kinase) and IRE (inositol-requiring enzyme) 1alpha. Co-treatment of 4-PBA dramatically impaired the inhibitory effect of GA on cell viability. 4PBA co-treatment also decreased expression levels of GRP78, CHOP, ATF6, and caspase12, as well as the phosphorylation levels of PERK and IRE1alpha, in GA-treated NSCLC cells, without affecting ROS levels. CONCLUSIONS GA inhibited NSCLC cell proliferation by inducing ROS-induced ER stress-medicated apoptosis of NSCLC cells.

Topics: A549 Cells; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Survival; China; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endoribonucleases; Heat-Shock Proteins; Humans; Lung Neoplasms; Phenylbutyrates; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Signal Transduction; Transcription Factor CHOP; Xanthones

BACKGROUND Activation of Notch signaling was found to be associated with cancer. Gambogic acid (GA) was reported to be an anti-cancer agent. This study investigated the anti-cancer effect of GA on human non-small cell lung cancer (NSCLC) cells. Involvement of the Notch pathway was also studied. MATERIAL AND METHODS GA at 0, 0.5, 0.75, and 1.0 μmol/l was used to incubate A549 and SPC-A1 cells. MTT assay was used to determine the cell viability. TUNEL assay was used to detect the apoptosis. Western blotting was used to evaluate protein expression levels, protein phosphorylation levels, and nuclear translocation levels. RESULTS Notch signaling pathway was activated in NSCLC cells. GA treatment significantly inhibited NSCLC cell viability and increased cell apoptosis. GA treatment significantly decreased the expression levels of DLL1, DLL3, DLL4, Jagged1, Jagged2, Bcl2, and PK3K, inhibited NICD nuclear translocation and Akt phosphorylation, and increased expression level of active caspase3. CONCLUSIONS GA inhibited NSCLC cell viability by inducing apoptosis. Inhibition of the Notch signaling pathway was the mechanism involved in the anti-proliferation effect of GA on NSCLC.

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Cell Survival; Humans; Lung Neoplasms; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Receptors, Notch; Signal Transduction; Xanthones

Garcinia hanburyi is a traditional herbal medicine with activities of anti-inflammation and hemostasis used by people in South Asia. Gambogic acid (GA) is the main active component extracted from it, which has anticancer and anti-inflammatory effects. The aim of the current study is to investigate the molecular mechanisms of GA's effective anticancer activity.. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to measure cell proliferation. Apoptosis induced by GA was analyzed by flow cytometry. In addition, monodansylcadaverine (MDC) and 2',7'-dichlorofluorescein diacetate were used to evaluate autophagy and reactive oxygen species (ROS) generation, respectively.. GA could significantly inhibit nonsmall cell lung cancer (NSCLC) NCI-H441 cell growth. In addition, GA induced NCI-H441 cells autophagy, confirmed by MDC staining, upregulation of Beclin 1 (initiation factor for autophagosome formation), and conversion of LC3 I to LC3 II (autophagosome marker). Moreover, generated ROS was induced by GA in NCI-H441 cells and the ROS scavenger N-acetylcysteine reversed GA-induced autophagy and restored the cell survival, which indicated GA-induced autophagy in NCI-H441 cells through an ROS-dependent pathway. In addition, in vivo results further indicated that GA significantly inhibited the growth of NCI-H441 xenografts.. The results shed new light on the interaction between ROS generation and autophagy in NSCLC cells and provide theoretical support for the usage of GA in clinical treatment.

Topics: Acetylcysteine; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Cell Survival; Female; Garcinia; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Reactive Oxygen Species; Signal Transduction; Xanthones; Xenograft Model Antitumor Assays

Gambogic acid (GA), a xanthone derived from the resin of the Garcinia hanburyi, has been demonstrated possessing anti-metastatic activity in vitro and in vivo. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a membrane-anchored glycoprotein negatively regulating matrix metalloproteinases (MMPs), plays an important role in tumor invasion and metastasis. The present study investigates the regulatory effect of GA on RECK expression and the role of RECK in GA-induced anti-invasion in A549 human lung cancer cells. Our results showed that GA dose-dependently inhibited cell invasion and suppressed A549 experimental lung metastasis in vivo, which was attributed to RECK up-regulation at both protein and mRNA levels. With small interference RNA (siRNA) blocking RECK expression, we found inhibition of RECK decreased the GA-induced inhibition of MMP-2/9, which was in consistent with the attenuated anti-invasive effect of GA. Further study indicated that GA effectively suppressed Histone deacetylase (HDAC) 1/specificity protein (Sp) 1 binding and Sp1 phosphorylation associating with Extracellular signal-regulated kinases (ERK) signaling blocking, leading to RECK up-regulation. Taken together, these data demonstrate that RECK contributes to GA's anti-invasive activity and provide new evidence for GA being served as a therapeutic candidate for cancer metastasis.

Topics: Animals; Base Sequence; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; DNA Primers; GPI-Linked Proteins; Heterografts; Histone Deacetylases; Humans; Lung Neoplasms; MAP Kinase Signaling System; Mice; Mice, Nude; Neoplasm Invasiveness; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Sp1 Transcription Factor; Xanthones

Gambogic acid (GA) has been approved by the Chinese Food and Drug Administration for the treatment of lung cancer in clinical trials. However, whether GA has chemosensitizing properties when combined with other chemotherapy agents in the treatment of lung cancer is not known. Here we investigated the effects of GA combined with adriamycin (ADM), a common chemotherapy agent, in regard to their activities and the possible mechanisms against lung cancer in vitro and in vivo. Cell viability results showed that sequential GA-ADM treatment was synergistic, while the reverse sequence and simultaneous treatments were antagonistic or additive, in lung cancer cells and ADM resistant cells, but not in normal cells. The combined use of GA and ADM synergistically displayed apoptosis-inducing activities in lung cancer cells. Moreover, GA in combination with ADM could promote PARP cleavage, enhance caspases activation and decrease the expression of anti-apoptotic proteins in lung cancer cells. The combined use of GA and ADM decreased the expression of P-glycoprotein and increased the accumulation of ADM in lung cancer cells. Furthermore, it was found that, prior to ADM treatment, GA could inhibit NF-κB signaling pathways, which have been validated to confer ADM resistance. The critical role of NF-κB was further confirmed by using PDTC, a NF-κB inhibitor, which significantly increased apoptosis induction by the combination of GA and ADM and inhibited ADM-induced ABCB1 upregulation. Importantly, our results indicated that the combination of GA and ADM exerted enhanced anti-tumor effects on A549 xenograft models through inhibiting NF-κB and P-glycoprotein, and attenuated ADM-induced cardiotoxicity. Collectively, these findings indicate that GA sensitizes lung cancer cells to ADM in vitro and in vivo, providing a rationale for the combined use of GA and ADM in lung cancer chemotherapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Doxorubicin; Humans; Lung Neoplasms; Male; Mice; Mice, Inbred BALB C; NF-kappa B; Signal Transduction; Xanthones; Xenograft Model Antitumor Assays

Gambogic acid (GA) has been reported to have potent anticancer activity and is authorised to be tested in phase II clinical trials for treatment of non-small-cell lung cancer (NSCLC). The present study aims to investigate whether GA would be synergistic with cisplatin (CDDP) against the NSCLC.. 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT), combination index (CI) isobologram, western blot, quantitative PCR, flow cytometry, electrophoretic mobility shift assay, xenograft tumour models and terminal deoxynucleotide transferase-mediated dUTP nick-end labelling analysis were used in this study.. The cell viability results showed that sequential CDDP-GA treatment resulted in a strong synergistic action in A549, NCI-H460, and NCI-H1299 cell lines, whereas the reverse sequence and simultaneous treatments led to a slight synergistic or additive action. Increased sub-G1 phase cells and enhanced PARP cleavage demonstrated that the sequence of CDDP-GA treatment markedly increased apoptosis in comparison with other treatments. Furthermore, the sequential combination could enhance the activation of caspase-3, -8, and 9, increase the expression of Fas and Bax, and decrease the expression of Bcl-2, survivin and X-inhibitor of apoptosis protein (X-IAP) in A549 and NCI-H460 cell lines. In addition, increased apoptosis was correlated with enhanced reactive oxygen species generation. Importantly, it was found that, followed by CDDP treatment, GA could inhibit NF-κB and mitogen-activated protein kinase (MAPK)/heme oxygenase-1 (HO-1) signalling pathways, which have been validated to reduce ROS release and confer CDDP resistance. The roles of NF-κB and MAPK pathways were further confirmed by using specific inhibitors, which significantly increased ROS release and apoptosis induced by the sequential combination of CDDP and GA. Moreover, our results indicated that the combination of CDDP and GA exerted increased antitumour effects on A549 xenograft models through inhibiting NF-κB, HO-1, and subsequently inducing apoptosis.. Gambogic acid sensitises lung cancer cells to CDDP in vitro and in vivo in NSCLC through inactivation of NF-κB and MAPK/HO-1 signalling pathways, providing a rationale for the combined use of CDDP and GA in lung cancer chemotherapy.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Apoptosis Regulatory Proteins; Carcinoma, Non-Small-Cell Lung; Caspases; Cell Line, Tumor; Cell Survival; Cisplatin; Down-Regulation; Drug Synergism; Heme Oxygenase-1; Humans; Lung Neoplasms; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; NF-kappa B; Reactive Oxygen Species; Signal Transduction; Xanthones

Gambogic acid (GA) is one of the important active ingredients of gamboge. Our study examined the expression of transferrin receptors (TFR) on the cell surface of human lung SPC-A1 and SK-MES-1 cells and measured their GA-induced apoptosis rate. The results showed that SPC-A1 cells with a higher TFR expression were more sensitive at the same GA concentrations. To examine its distribution in cultured cells and study the mechanisms of apoptosis, we labeled GA with a (125)I tracer and examined the expression of apoptosis-related proteins. we found that GA uptake into SPC-A1 cells was higher than into SK-MES-1 cells; apoptosis-related proteins Caspase 2, Caspase 9, Caspase 10, Bax and p53 were involved in GA-induced apoptosis. We conclude that GA has an apoptosis-promoting effect on non small cell lung cancer cells. In clinical practice, the histopathological quantitation of TFR expression levels in tumor tissues may become a predictor of the sensitivity of patients' tumors to GA treatment.

Topics: Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Separation; Drug Resistance, Neoplasm; Flow Cytometry; Gene Expression; Humans; Immunohistochemistry; Lung Neoplasms; Receptors, Transferrin; Xanthones