Ginkgolide C Alleviates Acute Lung Injury Caused by Paraquat Poisoning via Regulating the Nrf2 and NF-κB Signaling Pathways.

Paraquat (PQ), a highly toxic herbicide and primary attack for lung, results in severe acute lung injury (ALI) appeared as evident oxidative stress, inflammation, and apoptosis. Increasing evidence elucidates that nuclear factor erythroid-2-related factor 2 (Nrf2) and its associated nuclear factor-κB (NF-κB) exhibit many merits for protection of ALI by coordinating a fine-turned response to oxidative stress, inflammation, and apoptosis. Ginkgolide C (GC) has been reported to be a safe and potent therapeutic agent against ALI. However, whether GC could protect ALI induced by PQ poisoning and the possible underlining mechanisms have remained not to be fully elucidated. A rat model of ALI and a model of acute type II alveolar epithelial cell (RLE-6TN) injury constructed by exposure to PQ were applied to discuss the protective effect of GC. Furthermore, Nrf2 gene silencing RLE-6TN cells were used to discuss the exact mechanism. We confirmed that GC significantly ameliorated the histopathological damages, ultrastructural changes, lung injury score, W/D ratio, and Hyp activity of lung tissue and inhibited polymorphonuclear neutrophil (PMN) infiltration after PQ poisoning. Further results revealed that GC remarkably activated Nrf2-based cytoprotective system and inhibited NF-κB-induced inflammatory injury as well as apoptosis. Taken together, we concluded that GC preserved protection of PQ-induced ALI via the Nrf2-NF-κB dependent signal pathway, which may provide us novel insights into the treatment strategies for PQ poisoning.

Development and Validation of an Unethical Professional Behavior Tendencies Scale for Student Teachers.

Teacher's unethical professional behaviors affect students' physical and mental health. Prevention should start with student teachers, but empirical research is lacking in China. This study surveyed over 2,000 student teachers from China to examine the psychometric properties of a student teachers' unethical professional behavior tendencies scale which revised by primary and secondary school teachers' unethical professional behavior tendencies scale. Exploratory and confirmatory factor analysis confirmed that a bi-factor model fit the data best. The final student teachers' unethical professional behavior tendencies scale comprised four subscales, including a general factor (unethical professional behaviors) and four special factors (perfunctory attitude and carelessness, insults and discrimination, unfairness, and using power for personal gain). The student teachers' unethical professional behavior tendencies scale correlated negatively with their professional ethical values and positively with perceived frequency of unethical professional behaviors of college teachers around them. The data supported the scale's measurement invariance across gender, and male student teachers scored significantly higher on unethical professional behavior tendencies than female student teachers. The findings suggest that the student teachers' unethical professional behavior tendencies scale is a useful instrument for assessing student teachers' unethical professional behaviors in China.

An overview of potential therapeutic agents to treat COVID-19.

The emerging novel coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has swept across the world and become a global threat to public health. More than 200 countries and territories worldwide are suffering from this COVID-19 pandemic. Worryingly, no specific vaccines or drugs have been approved for the prevention or treatment of COVID-19. Under the pressure of a sustained rise in the incidence and mortality of COVID-19, an unprecedented global effort is being implemented to identify effective drugs to combat the current coronavirus. As the understanding of SARS-CoV-2 virology, the underlying mechanism by which it attacks host cells, and the host response to the infection rapidly evolves, drugs are being repurposed and novel drugs are being identified and designed to target the SARS-CoV-2 pathogenesis. Presented here is a brief overview of both virus-based and host-based potential therapeutic drugs that are currently being investigated.

Diagnosis-related group (DRG)-based case-mix funding system, a promising alternative for fee for service payment in China.

Fee for services (FFS) is the prevailing method of payment in most Chinese public hospitals. Under this retrospective payment system, medical care providers are paid based on medical services and tend to over-treat to maximize their income, thereby contributing to rising medical costs and uncontrollable health expenditures to a large extent. Payment reform needs to be promptly implemented to move to a prospective payment plan. The diagnosis-related group (DRG)-based case-mix payment system, with its superior efficiency and containment of costs, has garnered increased attention and it represents a promising alternative. This article briefly describes the DRG-based case-mix payment system, it comparatively analyzes differences between FFS and case-mix funding systems, and it describes the implementation of DRGs in China. China's social and economic conditions differ across regions, so establishment of a national payment standard will take time and involve difficulties. No single method of provider payment is perfect. Measures to monitor and minimize the negative ethical implications and unintended effects of a DRG-based case-mix payment system are essential to ensuring the lasting social benefits of payment reform in Chinese public hospitals.

China's achievements and challenges in improving health insurance coverage.

China has undertaken waves of healthcare reforms to keep pace with its rapid economic growth. By 2011, universal health insurance coverage was successfully achieved through the creation of a basic social medical insurance system. Growing economic power, extensive government subsidies, and strategies for program implementation are critical to that achievement. However, the breadth and depth of coverage varies considerably across insurance schemes and localities. The disjointed insurance scheme led to inequality in coverage, accessibility, and affordability of medical services, lopsided allocation of health resources, and increasing medical expenditures, and these remain crucial challenges for healthcare insurance coverage. This paper describes societal conditions, polices, achievements and challenges in improving health insurance coverage in China. Thailand's experience in universal health insurance coverage and its implications for China's new medical reform are also discussed. Solutions including sustainable increases in government investment, transformation of payment methods, reinforcement of primary health care delivery and the referral system, and standardization of benefits packages are strongly recommended to address challenges in China's long-running medical reform.

A novel anticancer diarylurea derivative HL-40 as a multi-kinases inhibitor with good pharmacokinetics in Wistar rats.

HL-40, N-(4-(1-(4-chlorine indazole)) phenyl)-N-(4-chloro-3-three fluorine methyl phenyl) urea, is a novel diarylurea derivative. In this study, we investigated the kinases activities and binding constants, pharmacokinetics of HL-40, and then evaluated its anticancer efficacy by both in vitro and in vivo methods. Enzyme activities assays in vitro were employed to identify eight candidate kinase targets. The competition binding assays against eight candidate kinases suggested that HL-40 showed strong affinity to c-Kit, PDGFRß and FLT3. The pharmacokinetic studies in Wistar rats showed that HL-40 could maintain high compound concentration and long residence time in the blood circulation. HL-40 possessed strong inhibition activities against 12 human cancer cells. Meanwhile, HL-40 effectively delayed the growth of cancer xenografts without significant toxicity to mice. Based on these in vitro and in vivo results, we suggested that HL-40 might be developed as a potential multi-kinases inhibitor for cancer treatment.

1082-39, an analogue of sorafenib, inhibited human cancer cell growth more potently than sorafenib.

PURPOSE: 1082-39, an analogue of sorafenib, is a derivative of indazole diarylurea. We evaluated the activity of 1082-39 against human cancer cell growth. Its effects and mechanisms of action were then compared with those of sorafenib. The experiments were performed in human melanoma M21 cells. METHODS: Cell viability was estimated by using the colorimetric assay. Annexin V-FITC/PI staining assay was used to recognize the apoptotic cells. Further analysis of the mitochondria membrane potential (MMP) was performed by the JC-1 fluorescence probe staining. The levels of apoptotic proteins and kinases related to cancer proliferation were determined by western blotting assay. RESULTS: 1082-39 possessed the activity against cancer cell proliferation with time- and dose-dependent manner. 1082-39 induced M21 cell to apoptosis, showing the increase of annexin V-FITC/PI staining cells, the MMP collapse and releasing cytochrome c from mitochondria. Western blotting analysis showed the activation of the mitochondria-mediated intrinsic pathway, showing the increase of cleaved caspase-9, cleaved caspase-3 and cleaved PARP. Statistical analysis suggested that 1082-39 possessed greater activities than sorafenib in the inhibition of M21 proliferation and induction of apoptosis. These effects of 1082-39 might arise from its activity of regulation the PI3K/Akt and Wnt/ß-catenin signaling pathways. CONCLUSIONS: 1082-39 is a promising candidate compound which could develop as a potent anticancer agent.

Pharmacokinetics and metabolism of SL-01, a prodrug of gemcitabine, in rats.

PURPOSE: SL-01, dodecyl-3-((1-((2R,4R,5R)-3,3-difluoro-4-hydroxy-5-(hydroxymethyl)-tetrahydrofuran-2-yl)-2-oxo-1,2-dihydropyrimidin-4-yl) carbamoyl) pyrazine-2-carboxylate, is a prodrug of gemcitabine. Our previous reports suggested that SL-01 possesses superior bioavailability and anticancer activity to gemcitabine in mice. In this study, its pharmacokinetics and metabolisms were investigated in rats. METHODS: The pharmacokinetics of SL-01 was studied following intravenous or oral administration of SL-01 to Sprague-Dawley rats. The metabolites profile of SL-01 was further determined in rats receiving intravenous administration of SL-01. Blood samples were analyzed by using LC-MS or LC-MS/MS assay. RESULTS: Following administration with SL-01 intravenously or orally, SL-01, plasma gemcitabine released from SL-01 as well as the sum of gemcitabine (gemcitabine converted from SL-01 and plasma gemcitabine) exhibited higher values of V z /F and CL z /F, and longer MRT and t 1/2 than those of gemcitabine administered intravenously. The C max of gemcitabine produced by intravenous SL-01 was higher than that of gemcitabine dosed intravenously. The absolute bioavailability for the sum of gemcitabine was 32.2 % for intravenous and 22.2 % for oral administration with SL-01, respectively. After a single intravenous administration, a total of 5 components (M1, M2, M3, M4, and M5) were detected and identified as the metabolites of SL-01 in the plasma of rats. M1 and M2 were formed from the methylation and reduction of SL-01, respectively. Hydrolysis of the amide bond of SL-01 gave M3 and M4. M5 was produced from further dealkylation of M3. CONCLUSIONS: SL-01 displayed improved absorption, good distribution, high clearance, long mean residence time, and moderate bioavailability after administered intravenously or orally to rats. The major metabolic pathways of SL-01 involved methylation, reduction, hydrolysis, and dealkylation. These results suggested that SL-01 acts as a prodrug of gemcitabine in rats.

Synthesis of indazole based diarylurea derivatives and their antiproliferative activity against tumor cell lines.

New series of indazole based diarylureas were synthesized and their anticancer activity against cancer cells H460, A549, OS-RC-2, HT-29, Lovo, HepG2, Bel-7402, SGC-7901 and MDA-MB-231 were examined. These derivatives of diarylureas, except azaindazole based diarylureas 5f, 5l and 5m, showed superior or similar activity against most of these selected cancer cell lines to the reference compound sorafenib. The effect of substituents on the indazole ring was also investigated. Derivatives with trifluoromenthy or halogen substituent on the indazole ring showed higher activity against the selected cancer cell lines than sorafenib. The acute toxicity assay showed that compounds 5a, 5b and 5i possessed lower toxicity than sorafenib. Compound 5i with 4-(trifluoromenthy)-1H-indazole and 4-(trifluoromenthy) benzene moieties exhibited the most potent anticancer activity.

Riccardin D-26, a synthesized macrocyclic bisbibenzyl compound, inhibits human hepatocellular carcinoma growth through induction of apoptosis in p53-dependent way.

Riccardin D-26 is a synthesized macrocyclic bisbibenzyl compound. We investigated the effect of Riccardin D-26 on human hepatocellular carcinomas. Riccardin D-26 possessed stronger activity against SMMC-7721 cells than human normal liver cells. Riccardin D-26 injection effectively delayed the growth of SMMC-7721 xenografts in mice without significant toxicity. This effect of Riccardin D-26 was associated with the status of p53 and its targets, bax and p21(Waf1)(/)(Cip1). Riccardin D-26 activated p53 expression and induced cancer cells to apoptosis through the p53-mediated transcription-dependent and -independent pathway. Overall, Riccardin D-26 may inhibit hepatocellular carcinoma growth through induction of apoptosis in p53-dependent pathway.

Riccardin D-26, a synthesized macrocyclic bisbibenzyl compound, inhibits human oral squamous carcinoma cells KB and KB/VCR: In vitro and in vivo studies.

BACKGROUND: Riccardin D-26, a synthesized macrocyclic bisbibenzyl compound, might possess anti-cancer properties. We aimed to evaluate the efficacy of Riccardin D-26 as a candidate compound for treatment of cancers with sensitive or drug resistant cells. METHODS: Experiments were performed on human oral squamous carcinoma KB cells and vincristin-selected MDR KB/VCR cells. The inhibition of cell growth was evaluated by colorimetric and clonogenic assays. The apoptotic cells were determined by the Annexin V-FITC/PI staining assay. JC-1 fluorescence probe was used to examine the mitochondria membrane potential (MMP). Further experiments were performed in nude mice bearing KB or KB/VCR xenografts. Riccardin D-26 was administered by injection for 2weeks. The specimens of KB and KB/VCR xenografts were removed for TUNEL staining and Western blotting analysis. RESULTS: Riccardin D-26 significantly inhibited cancer growth in both KB and KB/VCR cells. Riccardin D-26's activity in cancer cells was greater than that in human normal liver cells. In mice, Riccardin D-26 effectively prevented the growth of KB and KB/VCR xenografts without significant toxicity. Further studies suggested that Riccardin D-26 inhibited cancer growth by inducing apoptosis in the activation of mitochondria-mediated intrinsic apoptosis pathway. Riccardin D-26 also possessed this activity in regulation of mitogen-related protein kinases such as MAPK and PI3K/Akt, which is associated with its inhibitory effect on KB/VCR cells. CONCLUSIONS: Riccardin D-26 possessed an anti-proliferation activity against both sensitive KB and MDR KB/VCR cancer cells. GENERAL SIGNIFICANCE: Riccardin D-26 could be a promising agent for treatment of cancers with sensitive or drug resistant cells.

Synthesis and biological evaluation of oral prodrugs based on the structure of gemcitabine.

A series of oral prodrugs based on the structure of gemcitabine (2',2'-difluorodeoxycytidine) were synthesised by introducing an amide group at the N4-position of the cytidine ring. A total of 16 compounds were obtained, and their chemical and biological characteristics were evaluated. The half-maximal inhibitory concentrations (IC(50)s) for most of these compounds were higher than that of gemcitabine in vitro. Compounds 5d and 5m, the representative compounds, were examined in terms of their physiological stabilities and pharmacokinetics. Compound 5d showed good stability in PBS and simulated intestinal fluid, and an analysis of its pharmacokinetics in mice suggested that the introduction of an amide group to gemcitabine could greatly improve its bioavailability. Further evaluation of compound 5d in vivo showed that this compound possesses higher activity than gemcitabine against the growth of HepG2 human hepatocellular carcinoma cells and HCT-116 colon adenocarcinoma cells with less toxicity to animals. These results suggest that compound 5d could be further developed as a potential oral anticancer agent for clinical applications in which gemcitabine is currently used.

SL-01, an oral gemcitabine derivative, inhibited human cancer growth more potently than gemcitabine.

SL-01, an oral gemcitabine derivative, was synthesized by introducing the moiety of 3-(dodecyloxycarbonyl)pyrazine-2-carbonyl at the N4-position on the cytidine ring of gemcitabine. Our goal in this study was to evaluate the efficacy of SL-01 on the growth of human cancers with gemcitabine as control. Experiments were performed on human non-small cell lung cancer NCI-H460 and colon cancer HCT-116 both in vitro and in vivo. In vitro assays, SL-01 significantly inhibited the growth of cancer cells as determined by the 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. Further studies indicated that SL-01 induced the cancer cells to apoptosis showing chromatin condensation and externalization of phosphatidylserine. In in vivo studies, we evaluated the efficacy of SL-01 in nude mice bearing human cancer xenografts. SL-01 effectively delayed the growth of NCI-H460 and HCT-116 without significant loss of body weight. Molecular analysis indicated that the high efficacy of SL-01 was associated with its ability to induce apoptosis as evidenced by increase of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining cells, activation of caspase-9, caspase-3 and cleaved poly ADP-ribose polymerase (PARP) in tumor tissues. SL-01 also increased Bax/Bcl-2 ratio in cancer cells. These biological activities of SL-01 were more potential than that of gemcitabine. Based on these in vitro and in vivo results, SL-01 is proposed as a potent oral anticancer agent that may supplant the use of gemcitabine in the clinic.

Inhibition of intestinal adenoma formation in APC(Min/+) mice by Riccardin D, a natural product derived from liverwort plant Dumortiera hirsuta.

BACKGROUND: Mutation of tumor suppressor gene, adenomatous polyposis coli (APC), is the primary molecular event in the development of most intestinal carcinomas. Animal model with APC gene mutation is an effective tool for study of preventive approaches against intestinal carcinomas. We aimed to evaluate the effect of Riccardin D, a macrocyclic bisbibenzyl compound, as a chemopreventive agent against intestinal adenoma formation in APC(Min/+) mice. METHODS: APC(Min/+) mice were given Riccardin D by p.o. gavage for 7 weeks. Mice were sacrificed, and the number, size and histopathology of intestinal polyps were examined under a microscope. We performed immunohistochemical staining, western blotting, reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) in intestinal polyps to investigate the mechanism of chemopreventive effect of Riccardin D. RESULTS: Riccardin D treatment resulted in a significant inhibition of intestinal adenoma formation, showing a reduction of polyp number by 41.7%, 31.1% and 44.4%, respectively, in proximal, middle and distal portions of small intestine. The activity of Riccardin D against polyp formation was more profound in colon, wherein Riccardin D decreased polyp number by 79.3%. Size distribution analysis revealed a significant reduction in large-size polyps (2-3 mm) by 40.0%, 42.5% and 33.3%, respectively, in proximal, middle and distal portions of small intestine, and 77.8% in colon. Histopathological analysis of the intestinal polyps revealed mostly hyperplastic morphology without obvious dysplasia in Riccardin D-treated mice. Molecular analyses of the polyps suggested that the inhibitory effect of Riccardin D on intestinal adenoma formation was associated with its abilities of reduction in cell proliferation, induction of apoptosis, antiangiogenesis, inhibition of the Wnt signaling pathway and suppression of inflammatory mediators in polyps. CONCLUSIONS: Our results suggested that Riccardin D exerts its chemopreventive effect against intestinal adenoma formation through multiple mechanisms including anti-proliferative, apoptotic, anti-angiogenic and anti-inflammatory activity.

Inhibitory effect of riccardin D on growth of human non-small cell lung cancer: in vitro and in vivo studies.

Riccardin D is a macrocyclic bisbibenzyl compound extracted from liverwort plant Dumortiera hirsuta. Our previous study showed that riccardin D induced apoptosis of human leukemia cells by targeting DNA topoisomerase II (topo II). Riccardin D has been considered as a novel DNA topo II inhibitor and potential chemotherapeutic agent for treatment of cancers. In this study, we evaluated the inhibitory effects of riccardin D on growth of human non-small cell lung cancer (NSCLC) both in vitro and in vivo. Riccardin D effectively inhibited the proliferation of NSCLC cells as estimated by the MTT assay. Further examination showed that the ability of invasion and migration of NSCLC cells was suppressed on exposure to riccardin D as estimated by the assays of scratch and transwell chamber. The anticancer activity of riccardin D was verified in mice bearing human NSCLC H460 xenografts. Riccardin D injection produced a 44.5% inhibition of cancer growth without apparent signs of toxicity to animals. Further, riccardin D induced apoptosis of NSCLC cells as evidenced by the increases of cells with externalization of phosphatidylserine and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive in H460 xenografts. The analysis of apoptotic proteins showed that riccardin D activated the caspases cascade signaling pathway as demonstrated by the increases of cleaved caspase-3 and cleaved PARP in NSCLC cells in vitro and in H460 xenografts in mice. The pBR322 DNA relaxation assay indicated that riccardin D inhibited the activity of DNA topo II in H460 and A549 cells, suggesting the mechanism of riccardin D in induction of NSCLC apoptosis. In addition, we studied the activity and expression of matrix metalloproteinases (MMPs) in NSCLC cells. The activities of MMP-2 and MMP-9 in supernatants of NSCLC cells were suppressed on exposure to riccardin D as estimated by gelatin zymography assay. The inhibitory effects of riccardin D on expressions of MMP-2 and MMP-9 were verified in H460 xenografts in mice and the decreases of vascular endothelial growth factor (VEGF) and Erk1/2 might associate with the inhibition of MMPs and NSCLC growth. Together, our results suggest that riccardin D has a high inhibitory effect on human NSCLC growth through induction of apoptosis.

Riccardin D, a novel macrocyclic bisbibenzyl, induces apoptosis of human leukemia cells by targeting DNA topoisomerase II.

We studied the effect of riccardin D, a macrocyclic bisbibenzyl, which was isolated from the Chinese liverwort plant, on human leukemia cells and the underlying molecular mechanism. Riccardin D had a significant antiproliferative effect on human leukemia cell lines HL-60, K562 and its multidrug resistant (MDR) counterpart K562/A02 cells, but showed no effect on the topoisomerase-II-deficient HL-60/MX2 cells, as measured by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The pBR322 DNA relaxation assay revealed that riccardin D selectively inhibited the activity of topoisomerase II (topo II). The suppression of topo II activity by riccardin D was stronger than that of etoposide, a known topo II inhibitor. After treatment with riccardin D, nuclear extracts of leukemia K562 and K562/A02 cells left the majority of pBR322 DNA in a supercoiled form. Further examination showed that riccardin D effectively induced HL-60, K562 and K562/A02 apoptosis as evidenced by externalization of phosphatidylserine and formation of DNA ladder fragments. The activation of cytochrome c, caspase-9, caspase-3 and cleaved poly ADP-ribose polymerase (PARP) was also enhanced, as estimated by Western blot analysis. By contrast, riccardin D was unable to induce apoptosis in the topoisomerase-II-deficient HL-60/MX2 cells, indicating that the induction of apoptosis by riccardin D was due to the inhibition of topo II activity. In addition, riccardin D was able to significantly decrease P-glycoprotein (P-gp) expression in K562/A02 cells. Taken together, our data demonstrate that riccardin D is a novel DNA topo II inhibitor which can induce apoptosis of human leukemia cells and that it has therapeutic potential for both regular and MDR strains of leukemia cells.

Inhibition of angiogenesis involves in anticancer activity of riccardin D, a macrocyclic bisbibenzyl, in human lung carcinoma.

Riccardin D is a novel macrocyclic bisbibenzyl compound extracted from Chinese liverwort plant Dumortiera hirsuta. Our previous studies showed that riccardin D is a DNA topo II inhibitor and has therapeutic potential for treatment of cancers. In this combined in vitro and in vivo study, we examined the inhibitory effects of riccardin D on tumor angiogenesis and the subsequent effect of anticancer activity was evaluated. Incubation with riccardin D weakly inhibited the proliferation of human umbilical vascular endothelial cells (HUVEC) as estimated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The scratch wound experiment showed that riccardin D effectively decreased the motility and migration of HUVEC cells. Riccardin D inhibited the formation of capillary tube as demonstrated by decrease of branch points formed by HUVEC cells on 3-D Matrigel. We examined the levels of angiogenic factors including vascular endothelial growth factor (VEGF), VEGF receptor 2, epidermal growth factor receptor (EGF receptor), and matrix metalloproteinase (MMPs) in HUVEC cells. The expressions of VEGF, phospho-VEGF receptor 2, EGF receptor and MMP-2 were significantly reduced by riccardin D as estimated by Western blot assay and real-time quantitative PCR analysis. The decrease of VEGF was also detected in riccardin D-treated human lung cancer H460 cells. The anticancer activity of riccardin D was then evaluated in a mouse model in which riccardin D delayed the growth of H460 xenografts without obvious toxicity to animals after three weeks injection. To evaluate the role of antiangiogenesis of riccardin D in mice, CD34 immunohistochemical staining was employed to analyze the mean vascular density in H460 xenograft tissues. The number of blood vessels was significantly decreased after riccardin D treatment. These results suggest that riccardin D display the inhibitory effect on growth of human lung carcinoma cells and that the inhibition of angiogenesis may involve in anticancer activity of riccardin D.

Des-γ-carboxyl prothrombin induces matrix metalloproteinase activity in hepatocellular carcinoma cells by involving the ERK1/2 MAPK signalling pathway.

Des-γ-carboxy prothrombin (DCP), an aberrant prothrombin produced by hepatocellular carcinoma (HCC) cells, has been shown to be associated with the biological malignant potential of HCC. The aim of this study was to evaluate the effect of DCP on HCC cell growth and metastasis, and to explore the underlying molecular mechanisms. DCP significantly stimulated HCC cell growth, as measured by cell counting kit-8 assay. Transwell chamber assay showed that DCP increased HCC cell migration through reconstituted extracellular matrix (Matrigel). Gelatin zymography assay and Western blot analysis demonstrated that DCP increased the secretion and expression of matrix metalloproteinase (MMP)-2 and MMP-9 in the supernatant of cultured HCC cells and on tumour cell membranes. DCP was found to bind to the cell surface receptor Met, resulting in Met phosphorylation and subsequent activation of the epidermal growth factor receptor (EGFR). Western blot analysis demonstrated that DCP stimulated a sequential kinase phosphorylation cascade including ERK1/2, MEK1/2 and c-Raf, indicating activation of the extracellular signal-regulated kinase/mitogen activated protein kinase (ERK1/2 MAPK) signalling pathway. Furthermore, blocking ERK1/2 MAPK activation with ERK1/2 inhibitor PD98059 essentially abolished the DCP-induced MMP-2 and MMP-9 activity, confirming the signalling pathway of DCP stimulation. Taken together, these results suggested that DCP stimulates HCC growth and promotes HCC metastasis by increasing the activity of MMP-2 and MMP-9 through activation of the ERK1/2 MAPK signalling pathway.

LYP, a novel bestatin derivative, inhibits cell growth and suppresses APN/CD13 activity in human ovarian carcinoma cells more potently than bestatin.

LYP is a bestatin dimethylaminoethyl ester which inhibits aminopeptidase N (APN/CD13). Our goal in this study was to evaluate LYP as a candidate compound for cancer treatment, beginning by studying its inhibitory effects on tumors and then comparing it to bestatin. Experiments were performed on human ovarian carcinoma (OVCA) ES-2 and SKOV-3 cell lines, which have high and low levels of APN/CD13 respectively. LYP effectively inhibited ES-2 cell growth as estimated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and the trypan blue dye-exclusion test. LYP significantly suppressed APN/CD13 activity on the surface of ES-2 cells as measured by quantifying the enzymatic cleavage of the substrate L-leucine-p-nitroanilide. The inhibitory effects of LYP were greater than those of bestatin at the same concentrations. In contrast, LYP was a weak inhibitor of SKOV-3 cell growth, suggesting that LYP may inhibit ES-2 cell growth via suppression of APN/CD13. Inhibition of APN/CD13 expression was also demonstrated with immunofluorescent flow cytometry and Western blot analysis. Inhibitory effects of LYP were confirmed by using a mouse model in which LYP delayed the growth of ES-2 xenografts in mice after 2 weeks of LYP injections. Inhibition of APN/CD13 expression was demonstrated in the ES-2 xenografts using Western blot analysis. The inhibitory effects of LYP on the ES-2 xenografts were stronger than those of bestatin. These results suggest that LYP has a powerful inhibitory effect on the growth of OVCA cells and that the mechanism may be via a decrease in the expression of APN/CD13.

Targeting aminopeptidase N (APN/CD13) with cyclic-imide peptidomimetics derivative CIP-13F inhibits the growth of human ovarian carcinoma cells.

Aminopeptidase N (APN/CD13) is an essential peptidase involved in the process of tumor growth, metastasis and angiogenesis. Inhibition of APN/CD13 may be an effective strategy for cancer treatment. CIP-13F is a cyclic-imide peptidomimetics compound designed to fit the active pockets S1 and S'1 of APN/CD13 that act in tumor proliferation. Our aim in this study was to evaluate the efficacy of CIP-13F as a candidate compound for cancer treatment. The experiments were performed on the human ovarian carcinoma (OVCA) ES-2 and HRA cell lines, which have high and low levels of APN/CD13 respectively. CIP-13F significantly blocked APN/CD13 activity on the surface of ES-2 cells as measured by quantitating the enzymatic cleavage of the substrate l-leucine-p-nitroanilide. CIP-13F effectively inhibited ES-2 cell growth and migration without significant cytotoxic effect. In contrast, CIP-13F did not significantly inhibit HRA cell growth, indicating that CIP-13F may inhibit ES-2 cell growth via suppression of APN/CD13. The suppression of APN/CD13 was also observed by using the assays of flow cytometry and Western blot analysis. Further, the inhibitory effects of CIP-13F on APN/CD13 and on ES-2 proliferation were supported by the induction of ES-2 apoptosis. CIP-13F-treated ES-2 cells resulted apoptotic characteristics, such as induction of externalization of phosphatidylserine and DNA laddering fragment. The activation of caspase-3 and poly ADP-ribose polymerase (PARP) was also enhanced. The inhibitory effects of CIP-13F on APN/CD13 expression and on ES-2 proliferation were confirmed in mice bearing ES-2 xenografts. CIP-13F delayed the growth of ES-2 xenografts in mice after 2 weeks of vena caudalis injection. These results suggest that CIP-13F has a high inhibitory effect on the growth of OVCA cells via decreasing the activity and expression of APN/CD13.