Involvement of cell cycle regulatory proteins and MAP kinase signaling pathway in growth inhibition and cell cycle arrest by a selective cyclooxygenase 2 inhibitor, etodolac, in human hepatocellular carcinoma cell lines

Insight into non-nucleoside triazole-based systems as viral polymerases inhibitors

Viruses have been recognized as the etiological agents responsible for many pathological conditions ranging from asymptomatic infections to serious diseases, even leading to death. For this reason, many efforts have been made to identify selective viral targets with the aim of developing efficient therapeutic strategies, devoid of drug-resistance issues. Considering their crucial role in the viral life cycle, polymerases are very attractive targets. Among the classes of compounds explored as viral polymerases inhibitors, here we present an overview of non-nucleoside triazole-based compounds identified in the last fifteen years. Furthermore, the structure-activity relationships (SAR) of the different chemical entities are described in order to highlight the key chemical features required for the development of effective antiviral agents.

SDTNBI: an integrated network and chemoinformatics tool for systematic prediction of drug-target interactions and drug repositioning

Computational prediction of drug-target interactions (DTIs) and drug repositioning provides a low-cost and high-efficiency approach for drug discovery and development. The traditional social network-derived methods based on the naïve DTI topology information cannot predict potential targets for new chemical entities or failed drugs in clinical trials. There are currently millions of commercially available molecules with biologically relevant representations in chemical databases. It is urgent to develop novel computational approaches to predict targets for new chemical entities and failed drugs on a large scale. In this study, we developed a useful tool, namely substructure-drug-target network-based inference (SDTNBI), to prioritize potential targets for old drugs, failed drugs and new chemical entities. SDTNBI incorporates network and chemoinformatics to bridge the gap between new chemical entities and known DTI network. High performance was yielded in 10-fold and leave-one-out cross validations using four benchmark data sets, covering G protein-coupled receptors, kinases, ion channels and nuclear receptors. Furthermore, the highest areas under the receiver operating characteristic curve were 0.797 and 0.863 for two external validation sets, respectively. Finally, we identified thousands of new potential DTIs via implementing SDTNBI on a global network. As a proof-of-principle, we showcased the use of SDTNBI to identify novel anticancer indications for nonsteroidal anti-inflammatory drugs by inhibiting AKR1C3, CA9 or CA12. In summary, SDTNBI is a powerful network-based approach that predicts potential targets for new chemical entities on a large scale and will provide a new tool for DTI prediction and drug repositioning. The program and predicted DTIs are available on request.

Novel Triazole-Piperazine Hybrid Molecules Induce Apoptosis via Activation of the Mitochondrial Pathway and Exhibit Antitumor Efficacy in Osteosarcoma Xenograft Nude Mice Model

Mitochondria impart a crucial role in the regulation of programmed cell death and reactive oxygen species (ROS) generation, besides serving as a primary energy source. Mitochondria appeared as an important target for the therapy of cancer due to their significant contribution to cell survival and death. Here, we report the design and synthesis of a novel series of triazole-piperazine hybrids as potent anticancer agents. MCS-5 emerged as an excellent anticancer agent which showed better anticancer activity than the standard drug doxorubicin in in vitro and in vivo studies. MCS-5 displayed an IC₅₀ value of 1.92 μM and induced apoptosis in Cal72 (human osteosarcoma cell line) cells by targeting the mitochondrial pathway. This compound arrested the G2/M phase of the cell cycle and induced ROS production and mitochondrial potential collapse in Cal72 cells. MCS-5 displayed excellent anticancer activity in the Cal72 xenograft nude mice model, where it significantly reduced tumor progression, leading to enhanced life span in treated animals compared to control and doxorubicin treated animals without exerting noticeable toxicity. In addition, a 2DG optical probe guided study clearly evoked that MCS-5 remarkably reduced tumor metastasis in the Cal72 xenograft nude mice model. These results indicate that MCS-5 appeared as a novel chemical entity which is endowed with excellent in vitro as well as in vivo anticancer activity and may contribute significantly to the management of cancer in the future.

Recent advances bioactive 1,2,4-triazole-3-thiones

Triazoles are heterocyclic compounds which have a five-membered ring of two carbon atoms and three nitrogen atoms. These structures have been interest in the development of novel compounds with anticonvulsant, antidepressant, antioxidant, anti-inflammatory, analgesic, antinociceptive, antibacterial, antimycobacterial, antifungal, antiviral, anticancer, anti-parasitic, anti-urease and other activities. Therefore, many researchers have synthesized these compounds as target structures and evaluated their biological activities. This review contains various pharmacological activities of 1,2,4-triazole-3-thiones in one place and it is also the milestone for the new research towards this moiety.

Echographic detection of diethylnitrosamine-induced liver tumors in rats and the effect of the intratumoral injection of an inhibitor of c-Jun N-terminal kinase

BACKGROUND AND AIM

There have so far been few reports describing echographic studies of chemically-induced carcinogenesis in rodent livers. Using echography, we observed diethylnitrosamine-induced liver tumors in rats and examined the effect of an intratumoral injection of an inhibitor of c-Jun N-terminal kinase.

METHODS

Male Wistar rats were given 100 ppm of diethylnitrosamine for 6 weeks and their liver nodules were examined by echography weekly. The size of the nodules was measured and they were examined histologically. The effect of SP600125, an inhibitor of c-Jun N-terminal kinase, on the growth of rat hepatoma cell line McA-RH7777 was tested in vitro. Thereafter, SP600125 was injected into the liver nodules under echographic guidance in vivo and the changes in the proliferating cell nuclear antigen expression and size of the nodules were examined.

RESULTS

The four distinct lobes of rat livers were clearly observed by transabdominal echography. The nodules in the livers were first detected 6 weeks after the treatment began, when they were as small as 1.6 mm in diameter. The nodules thereafter became more malignant histologically as they grew larger than 4 mm. SP600125 decreased the expression of proliferating cell nuclear antigen and the growth of McA-RH7777 cells. After SP600125 was injected in vivo, the proliferating cell nuclear antigen level and the growth rate of the rat liver nodules all significantly decreased.

CONCLUSIONS

Our results indicate that echography is quite useful for follow-up studies of liver carcinogenesis in rats, and c-Jun N-terminal kinase might be another therapeutic target in liver neoplasms.

Advancements of cyclooxygenase inhibitor in the prevention and treatment of hepatoma

It was reported that the cyclooxygenase-2 (COX-2) and its products were over-expressed in many malignant tumors. Non-steroidal anti-inflammatory drugs (NSAIDs) can inhibit COX activity, and also can reduce proliferation, enhance apoptosis, decrease angiogenesis and invasiveness of tumor cells. Hepatoma is one of common malignancies worldwide, and its prognosis is still extremely poor and the cellular mechanisms contributing to hepatic carcinogenesis are relatively unknown. Therefore, the prevention and treatment of liver cancer are limited. At present, it is important to find new drugs and investigate their action mechanisms. This article provides a brief review on the research progress of COX inhibitor in the prevention and treatment of hepatoma.

Construction of pGL3-Basic-COX-2-promoter reporter gene vector and detection of its function

AIM: To construct COX-2 promoter recombined luciferase reporter gene vector, and to detect its function.

METHODS: Primers were designed based on human COX-2 gene promoter, then COX-2 promoter from human genome DNA was replicated. pGL3-Basic Vector and COX-2 promoter were digested with restriction enzymes Hind Ⅲ and Bgl Ⅱ separately, then COX-2 promoter was inserted into pGL3-Basic Vector. The recombinant vector pGL3-Basic-COX-2-promoter was transiently co-transfected into MKN45 cells with control vector pRL-SV40 respectively. twelve hours later, cells were treated with H. pylori 100 times amount of cells for different length of time, then the activity of dual luciferase was detected.

RESULTS: COX-2 promoter recombined luciferase reporter gene vector was constructed successfully, and the result of sequencing and double digesting of recombined plasmid were completely correct. The experiment of transient transfection showed that the expression of COX-2 promoter in MKN45 cells was increased with time. Activity of dual-luciferase after transfection for 40 h was 3.5 folds of that for 8 h (P < 0.05). When H. pylori was added to medium for co-culture, activity of dual-luciferase was increased up markedly compared with groups that were not added with H. pylori (P < 0.05 or 0.01), and it was 5 folds after transfection for 40 h than 8 h (P < 0.01).

CONCLUSION: pGL3-Basic-COX-2-promoter can be transcribed and activated in MKN45 cells, and activity of COX-2 promoter increases obviously after H. pylori addition. pGL3-Basic-COX-2-promoter can be used to identify and detect the level of COX-2 in cells.

Pro-apoptotic effect of nonsteroidal anti-inflammatory drugs on synovial fibroblasts

Rheumatoid arthritis (RA) is a systemic inflammatory disease that mainly affects the articular synovial tissues. Although the etiology of RA has not yet been elucidated, physical and biochemical inhibition of synovial hyperplasia, which is the origin of articular destruction, may be an effective treatment for RA. Nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used for the treatment of RA. The mechanism of action of NSAIDs generally involves the inhibition of cyclooxygenase (COX) at sites of inflammation. Thus, NSAIDs were not generally considered to have a so-called anti-rheumatic effect, including inhibition of progressive joint destruction and induction of remission. However, certain conventional NSAIDs and celecoxib, a selective COX-2 inhibitor, have been reported to inhibit synovial hyperplasia by inducing the apoptosis of human synovial fibroblasts. Therefore, it has been suggested that such NSAIDs may not only have an anti-inflammatory effect but also an anti-rheumatic effect. In this review, we summarize findings about the pro-apoptotic effect, in other words, anti-proliferative effect of NSAIDs on synovial fibroblasts from patients with RA.

OSU-03012, a Novel Celecoxib Derivative, Is Cytotoxic to Myeloma Cells and Acts through Multiple Mechanisms

PURPOSE

OSU-03012 is a novel celecoxib derivative, without cyclooxygenase-2 inhibitory activity, capable of inducing apoptosis in various cancer cells types, and is being developed as an anticancer drug. We investigated the in vitro activity of OSU-03012 in multiple myeloma (MM) cells.

EXPERIMENTAL DESIGN

U266, ARH-77, IM-9, and RPMI-8226, and primary myeloma cells were exposed to OSU-03012 for 6, 24, or 72 h. Cytotoxicity, caspase activation, apoptosis, and effects on intracellular signaling pathways were assessed.

RESULTS

OSU-03012 was cytotoxic to MM cells with mean LC50 3.69 +/- 0.23 and 6.25 +/- 0.86 micromol/L and at 24 h for primary MM cells and cell lines, respectively. As a known PDK-1 inhibitor, OSU-03012 inhibited the PI3K/Akt pathway with downstream effects on BAD, GSK-3beta, FoxO1a, p70S6K, and MDM-2. However, transfection of MM cells with constitutively active Akt failed to protect against cell death, indicating activity against other pathways is important. Phospho (p)-signal transducers and activators of transcription 3 and p-MAP/ERK kinase 1/2 were down-regulated, suggesting that OSU-03012 also inhibited the Janus-activated kinase 2/signal transducer and activator of transcription 3 and mitogen-activated protein kinase pathways. Although expression of Bcl-2 proteins was unchanged, OSU-03012 also down-regulated survivin and X-linked inhibitor of apoptosis (XIAP), and also induced G2 cell cycle arrest with associated reductions in cyclins A and B. Finally, although OSU-03012 induced cleavage of caspases 3, 8 and 9, caspase inhibition did not prevent cell death.

CONCLUSIONS

We conclude that OSU-03012 has potent activity against MM cells and acts via different mechanisms in addition to phosphoinositide-3-kinase/Akt pathway inhibition. These studies provide rationale for the clinical investigation of OSU-03012 in MM.

Vitamin K2 inhibits the proliferation of HepG2 cells by up-regulating the transcription of p21 gene

AIM

Vitamin K2 has been reported to inhibit the growth of human hepatocellular carcinoma (HCC) in vitro and suppress hepatocarcinogenesis in vivo. However, its inhibitory mechanism has not yet been clarified.

METHODS

Different concentrations of vitamin K2 (30, 10, 1, 0.1 and 0.01 muM) were added to the HCC cell line HepG2 to assess effects on cell growth. The effect of vitamin K2 on cell cycle progression was determined by flow-cytometric analysis. The expression of cell cycle regulatory proteins p21 and p27 was then examined by Western blot. Whether vitamin K2 regulates the gene expression through action on the p21 promoter region was investigated by luciferase assay.

RESULTS

Vitamin K2 inhibited the growth of HepG2 cells dose-dependently, and its inhibitory rate reached approximately 50% at the dose of 30 muM after 96 h treatment. After treatment with vitamin K2, the proportion of cells in G0-G1 phase increased, and in S phase decreased. Apoptotic cells were not detected. The expression of cell cycle regulatory protein p21 was induced by vitamin K2 treatment, but p27 was not. By the luciferase assay, vitamin K2 significantly activated the promoter of p21. Knock-down of p21 by siRNA reversed the growth inhibition of HepG2 cells by vitamin K2.

CONCLUSIONS

The findings suggest that vitamin K2 suppresses the proliferation of HCC cells by blocking the cell cycle G1/S progression through the transcriptional induction of p21.

Selective COX-2 inhibitor, NS-398, suppresses cellular proliferation in human hepatocellular carcinoma cell lines via cell cycle arrest

AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor, in two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7).

METHODS: HepG2 and Huh7 cells were treated with NS-398. Its effects on cell viability, cell proliferation, cell cycles, and gene expression were respectively evaluated by water-soluble tetrazolium salt (WST-1) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining, flow cytometer analysis, and Western blotting, with dimethyl sulfoxide (DMSO) as positive control.

RESULTS: NS-398 showed dose- and time-dependent growth-inhibitory effects on the two cell lines. Proliferating cell nuclear antigen (PCNA) expressions in HepG2 and Huh7 cells, particularly in Huh7 cells were inhibited in a time- and dose-independent manner. NS-398 caused cell cycle arrest in the G1 phase with cell accumulation in the sub-G1 phase in HepG2 and Huh7 cell lines. No evidence of apoptosis was observed in two cell lines.

CONCLUSION: NS-398 reduces cell proliferation by inducing cell cycle arrest in HepG2 and Huh7 cell lines, and COX-2 inhibitors may have potent chemoprevention effects on human hepatocellular carcinoma.

Specific COX-2 inhibitor, meloxicam, suppresses proliferation and induces apoptosis in human HepG2 hepatocellular carcinoma cells

BACKGROUND AND AIMS

Cyclooxygenase-2 (COX-2) is associated with carcinogenesis. The aim of this study was to investigate the expression of COX-2 in four hepatocellular carcinoma (HCC) cell lines, and evaluate the effect of a selective COX-2 inhibitor, meloxicam, in HepG2, a high COX-2 expressing cell line.

METHODS

Expression of COX-2 was detected using RT-PCR, Western blotting and immunohistochemical analysis. Cell proliferation was measured using MTT assay. Cell cycle distribution was determined by flow cytometry. Apoptosis was detected with TUNEL method. Expression of proliferating cell nuclear antigen (PCNA), cell cycle regulatory proteins including cyclins A, B1, D1 and E, and apoptosis-related proteins including Fas, Fas ligand and Bcl-2 were examined using Western blotting.

RESULTS

Cyclooxygenase-2 was intensely expressed in HepG2, HLE and BEL7402 cells, but weakly expressed in SMMC-7402 cells. Meloxicam suppressed proliferation of HepG2 cells in a dose- and time-dependent manner, resulting in cell cycle arrest in S phase and cell accumulation in G0/G1 phase. Expression of PCNA, cyclin A but not cyclin B1, cyclin D1 or cyclin E was down-regulated by meloxicam. Meloxicam also induced apoptosis of HepG2 cells, with increased expression of Fas ligand, but the expression of Fas and Bcl-2 was not affected by meloxicam treatment.

CONCLUSIONS

The present study demonstrates that the specific COX-2 inhibitor meloxicam suppresses proliferation and induces apoptosis in HCC cells that express COX-2, suggesting that COX-2 inhibition may offer a novel chemopreventive and therapeutic approach for HCC.

Cyclooxygenases in hepatocellular carcinoma

Many epidemiological studies demonstrate that treatment with non-steroidal anti-inflammatory drugs (NSAIDs) reduce the incidence and mortality of certain malignancies, especially gastrointestinal cancer. The cyclooxygenase (COX) enzymes are well-known targets of NSAIDs. However, conventional NSAIDs non-selectively inhibit both the constitutive form COX-1, and the inducible form COX-2. Recent evidence indicates that COX-2 is an important molecular target for anticancer therapies. Its expression is undetectable in most normal tissues, and is highly induced by pro-inflammatory cytokines, mitogens, tumor promoters and growth factors. It is now well-established that COX-2 is chronically overexpressed in many premalignant, malignant, and metastastic cancers, including hepatocellular carcinoma (HCC). Overexpression of COX-2 in patients with HCC is generally higher in well-differentiated HCCs compared with less-differentiated HCCs or histologically normal liver, suggesting that COX-2 may be involved in the early stages of hepatocarcinogenesis, and increased expression of COX-2 in noncancerous liver tissue has been significantly associated with shorter disease-free survival in patients with HCC.

In tumors, overexpression of COX-2 leads to an increase in prostaglandin (PG) levels, which affect many mechanisms involved in carcinogenesis, such as angiogenesis, inhibition of apoptosis, stimulation of cell growth as well as the invasiveness and metastatic potential of tumor cells.

The availability of novel agents that selectively inhibit COX-2 (COXIB), has contributed to shedding light on the role of this molecule. Experimental studies on animal models of liver cancer have shown that NSAIDs, including both selective and non-selective COX-2 inhibitors, exert chemopreventive as well as therapeutic effects. However, the key mechanism by which COX-2 inhibitors affect HCC cell growth is as yet not fully understood.

Increasing evidence suggests the involvement of molecular targets other than COX-2 in the anti-proliferative effects of COX-2 selective inhibitors. Therefore, COX-inhibitors may use both COX-2-dependent and COX-2-independent mechanisms to mediate their antitumor properties, although their relative contributions toward the in vivo effects remain less clear.

Here we review the features of COX enzymes, the role of the expression of COX isoforms in hepatocarcinogenesis and the mechanisms by which they may contribute to HCC growth, the pharmacological properties of COX-2 selective inhibitors, the antitumor effects of COX inhibitors, and the rationale and feasibility of COX-2 inhibitors for the treatment of HCC.

Chemoprevention of spontaneous development of hepatocellular carcinomas in fatty liver Shionogi mice by a cyclooxygenase-2 inhibitor

Cyclooxygenase 2 (COX-2) and retinoid X receptor alpha (RXRalpha) are suggested to have roles in carcinogenesis. COX-2 inhibitors have been reported to suppress growth of hepatocellular carcinoma (HCC) cell lines in vitro. However, little is known about the preventive effect of these drugs on spontaneous hepatocarcinogenesis in vivo. Etodolac exists in a racemic mixture containing S- and R-etodolac. S-etodolac is responsible for COX-2 inhibitory activity and R-etodolac is related to the downregulation of RXRalpha. Here, the effect of etodolac on spontaneous development of HCC in fatty liver Shionogi mice is evaluated. Etodolac was administered at a low (2 mg/kg) or high (10 mg/kg) dose three times a week for 16 months starting at the age of 3 months. The development of HCC was suppressed slightly in the high-dose group, and suppressed markedly in the low-dose group, although the development of fatty liver was not inhibited in either group. Plasma prostaglandin E2 levels were also decreased significantly in the low-dose group, consistent with the suppression of HCC. The expression of RXRalpha and proliferating cell nuclear antigen in non-tumorous liver tissues was decreased significantly in both the low-dose and high-dose groups. These findings show that etodolac treatment at an optimum dose suppresses hepatocarcinogenesis in vivo, and may be useful for preventing the development of HCC in humans.

Parthenolide cooperates with NS398 to inhibit growth of human hepatocellular carcinoma cells through effects on apoptosis and G0-G1 cell cycle arrest

Chemotherapy to date has not been effective in the treatment of human hepatocellular carcinoma. More effective treatment strategies may involve combinations of agents with activity against hepatocellular carcinoma. Parthenolide, a nuclear factor-kappaB (NF-kappaB) inhibitor, and NS398, a cyclooxygenase (COX)-2 inhibitor, have been shown to individually suppress the growth of hepatocellular carcinoma cells in vitro. To investigate their effects in combination, three human hepatocellular carcinoma lines (Hep3B, HepG2, and PLC) were treated with parthenolide and/or NS398. Parthenolide (0.1-10 micromol/L) and NS398 (1-100 micromol/L) each caused concentration-dependent growth inhibition in all cell lines. The addition of parthenolide to NS398 reduced the concentration of NS398 required to inhibit hepatocellular carcinoma growth. Because parthenolide and COX-2 inhibitors have been reported to influence NF-kappaB activity, the effects on this pathway were investigated. The combination of parthenolide/NS398 inhibited phosphorylation of the NF-kappaB-inhibitory protein IkappaBalpha and increased total IkappaBalpha levels. NF-kappaB DNA-binding and transcriptional activities were inhibited more by the combination than the single agents in Hep3B and HepG2 cells but not in PLC cells. The response of PLC cells to NS398 was augmented by p65 small interfering RNA to inhibit NF-kappaB p65 protein expression. The combination of parthenolide/NS398 increased apoptosis only in PLC cells, suggesting that the combination may decrease the apoptotic threshold in these cells. In Hep3B and HepG2 cells, combination treatment with NS398/parthenolide altered the cell cycle distribution resulting in more G0-G1 accumulation. Cyclin D1 levels were further decreased by combination treatment in all cell lines, correlating with the cell cycle alterations. Our results suggest that parthenolide may be effective in combination with COX-2 inhibitors for the treatment of hepatocellular carcinoma.

Significance of COX-2 expression in human esophageal squamous cell carcinoma

Cyclooxygenase-2 (COX-2) is well established to play an important role in the tumorigenesis of a variety of human cancers; however, the function of COX-2 in the development of esophageal squamous cell carcinoma (ESCC) remains less clear. Here, we determined, first, the pattern of COX-2 expression in normal esophageal mucosa, dysplasia, carcinoma in situ (CIS) and invasive SCC. Immunohistochemical analysis showed that, while COX-2 was weakly expressed, if at all, in normal squamous epithelium, strong COX-2 expression was detected as early as the stage of dysplasia and frequently in 20 of 26 (77%) CIS and 86 of 111 (77%) invasive SCC. Upregulation of COX-2 in ESCC was found to be significantly associated with tumor progression (R = 0.493, P < 0.01). Further, treatment of human ESCC cell lines (KYSE450 and KYSE510) with NS-398, a COX-2 specific chemical inhibitor, suppressed the production of prostaglandin E2 (PGE2) and induced cell growth inhibition, cell cycle arrest at the G1-S checkpoint, and the expression of cyclin-dependent kinase inhibitors p21waf1/cip1 and p27kip1. Finally, knockdown expression of COX-2 in KYSE450 cells by a specific COX-2 siRNA dramatically inhibited PGE2 production, cell growth and, more importantly, colony formation and tumorigenesis in nude mice. Together, this study suggested that COX-2 may be involved in an early stage of squamous cell carcinogenesis of the esophagus and has a non-redundant role in the regulation of cellular proliferation and tumorigenesis of esophageal epithelial cells.

The chemopreventive agent development research program in the Division of Cancer Prevention of the US National Cancer Institute: an overview

Chemoprevention is an innovative area of cancer research that focuses on the development of pharmacological, biological, and nutritional interventions to prevent, reverse, or delay carcinogenesis. Over the past two decades the Division of Cancer Prevention of the US National Cancer Institute has organized a research and development program to provide resources and infrastructure to the research community for the clinical evaluation of potential cancer preventive agents. This program now encompasses preclinical agent and molecular target identification, in vitro and in vivo screening, efficacy and intermediate endpoint testing, pharmacology and toxicology assessments, and finally chemical synthesis and manufacturing leading to Investigational New Drug applications and clinical studies. In this review, examples of agents currently in development, preclinical testing models, and phase 1 and 2 clinical studies are described. Continued commitment to cancer prevention will significantly reduce the economic and medical burden of cancer.

Combination of cyclooxygenase-2 inhibitors and oxaliplatin increases the growth inhibition and death in human colon cancer cells

The cyclooxygenase-2 (COX-2) protein is highly expressed in a variety of human cancers and has been reported to promote tumor growth. Non-steroidal anti-inflammatory drugs such as etodolac and celecoxib have been shown to inhibit COX-2 activity and may play a role in the chemoprevention of cancer. Oxaliplatin is a third-generation platinum compound that exhibits a different spectrum of activity compared with cisplatin. Other cisplatin-resistant tumors can still respond to oxaliplatin. However, the anticancer ability of the combination of COX-2 inhibitors and oxaliplatin is still unknown. In this study, we investigated the effects of combination of COX-2 inhibitors and oxaliplatin on the cell growth and survival in human colon cancer cells. Treatments with etodolac (0.3-0.5 mM) or celecoxib (20-80 microM) for 24 h concentration-dependently induced the cytotoxicity in the RKO colon carcinoma cells. Etodolac and celecoxib did not alter the COX-2 protein levels but inhibited its enzyme activity to reduce prostaglandin E2 production. Furthermore, the cell survival was concentration-dependently decreased following oxaliplatin (1-100 microM, 24 h) treatment. Combination of oxaliplatin and etodolac additively increased the death and growth inhibition of RKO cells. Survivin, an inhibitor protein of apoptosis, mediates anti-apoptosis and promotes cell division in cancer cells. Oxaliplatin or COX-2 inhibitors significantly decreased the levels of survivin proteins. Moreover, survivin proteins were markedly diminished following co-treatment with oxaliplatin and etodolac. Together, this is the first report that combination of COX-2 inhibitors and oxaliplatin can increase the reduction of survivin protein expression, growth inhibition, and death in human colon cancer cells.

Bioinformatics approaches for cross-species liver cancer analysis based on microarray gene expression profiling

Background

The completion of the sequencing of human, mouse and rat genomes and knowledge of cross-species gene homologies enables studies of differential gene expression in animal models. These types of studies have the potential to greatly enhance our understanding of diseases such as liver cancer in humans. Genes co-expressed across multiple species are most likely to have conserved functions. We have used various bioinformatics approaches to examine microarray expression profiles from liver neoplasms that arise in albumin-SV40 transgenic rats to elucidate genes, chromosome aberrations and pathways that might be associated with human liver cancer.

Results

In this study, we first identified 2223 differentially expressed genes by comparing gene expression profiles for two control, two adenoma and two carcinoma samples using an F-test. These genes were subsequently mapped to the rat chromosomes using a novel visualization tool, the Chromosome Plot. Using the same plot, we further mapped the significant genes to orthologous chromosomal locations in human and mouse. Many genes expressed in rat 1q that are amplified in rat liver cancer map to the human chromosomes 10, 11 and 19 and to the mouse chromosomes 7, 17 and 19, which have been implicated in studies of human and mouse liver cancer. Using Comparative Genomics Microarray Analysis (CGMA), we identified regions of potential aberrations in human. Lastly, a pathway analysis was conducted to predict altered human pathways based on statistical analysis and extrapolation from the rat data. All of the identified pathways have been known to be important in the etiology of human liver cancer, including cell cycle control, cell growth and differentiation, apoptosis, transcriptional regulation, and protein metabolism.

Conclusion

The study demonstrates that the hepatic gene expression profiles from the albumin-SV40 transgenic rat model revealed genes, pathways and chromosome alterations consistent with experimental and clinical research in human liver cancer. The bioinformatics tools presented in this paper are essential for cross species extrapolation and mapping of microarray data, its analysis and interpretation.

Three-dimensional high-density culture of HepG2 cells in a 5-ml radial-flow bioreactor for construction of artificial liver

A three-dimensional high-density cell culture is essential for the construction of an artificial tissue. Many researchers have reported that three-dimensional cell culture enhances cell function. The use of a radial-flow bioreactor (RFB) has enabled the cultivation of cells at high density for constructing a three-dimensional tissue. In this study, we have developed a novel, small RFB, which has a bed volume of 5 ml and is equipped with a porous support as an immobilized scaffold; its performance was tested using the hepatoblastoma cell line, HepG2. Among the other supports tested here, hydroxyl apatite was selected from the viewpoint of its ability to support good cell growth at high density with uniform distribution in a bioreactor. The HepG2 cells grew well in the scaffold under a sufficient supply of nutrients by radial flow and were used to construct a three-dimensional tissue in the scaffold. The concentration of the cells cultivated in this 5-ml RFB reached 10(8) cells/ml and the glucose consumption rate was almost similar to that obtained when using a 30-ml RFB, which has already been reported previously. This high glucose consumption continued over 7 d after the growth phase. Furthermore, albumin production was maintained in the stable phase. Gene expression profiles of cells obtained from long-term cultures in the 5-ml RFB were analyzed. It was found that the expressions of genes encoding the cell cycle-related proteins, cyclins, and cell cycle division 2 (cdc2) were suppressed in the stable phase. In addition, the number of cells incorporating 5'-bromo-2'-deoxyuridine (BrdU) in the stable phase markedly decreased compared with that in the growth phase. These results indicated that the majority of cells in the stable phase remain in the G0/G1 phase. Furthermore, this implies that the three-dimensional tissue constructed in the 5-ml RFB showed the high function similar to a normal liver in the human body. Therefore, the 5-ml RFB was considered as a useful tool and a substitute method for animal experiments.

Hepatocellular carcinoma: current management and future trends

The hallmarks of hepatocellular carcinoma (HCC) are that it is identified clinically at an advanced stage and usually together with cirrhosis. Surgical resection has been considered the optimal treatment approach, but only a small proportion of patients qualify for surgery, and there is a high rate of recurrence. Approaches to prevent recurrence have included chemoembolization before and neoadjuvant therapy after surgery, neither of which has proven to be beneficial. Liver transplantation has been successful in treating limited-stage HCC, affecting cure of both the tumor and underlying cirrhosis. However, only a minority of patients with HCC qualify for transplantation. Recently, chemoembolization has been shown to prolong survival in selected patients who do not qualify for transplantation or resection. Other innovative, relatively noninvasive local ablative therapies have been introduced and have been shown to be effective in reducing tumor size but not in prolonging survival. Standard chemotherapy is poorly tolerated in patients who do not qualify for resection. Both doxorubicin and cisplatin are frequently used, but overall response rates are low, and neither seems to prolong survival. Prospective, randomized controlled trials using current therapies are needed to better define optimal management of this important tumor. Most needed, however, are new therapeutic agents that are effective against HCC, are noncytotoxic, and are tolerated by the typical patient with underlying cirrhosis. Newly emerging agents with promise include 90 Y microspheres, antiangiogenesis agents, inhibitors of growth factors and their receptors, and K vitamins.