Abstract 3540: Down-regulation of solute carrier family 17 member 1(SLC17A1) expression contributes to chemotherapy resistance in acute myeloid leukemia

Cytosine arabinoside (Ara-C), an structural analogue of deoxycytidine, is generally considered to be the major drug in the treatment of AML. In acute myeloblastic leukemia (AML) treatment, resistance to cytotoxic nucleoside analogues is a major problem. To investigate novel genes associating with becoming Ara-C resistant cells, whole genome SNP chip analysis was performed. However, there was no significant in Ara-C metabolite genes. In that analysis, 12 region of loss of heterozygote (LOH) was found in non-CR group. SLC17 family gene and HIST1H family gene located in major of LOH in non-CR group. Since SLC29A1 expression levels directly affected the Ara-C mediated Apoptosis, we selected SLC17A1 among them and functional analysis of SLC17A1 was performed. Its expression levels were examined in four different AML cell lines using RT-PCR. Its expression level was a little different but that gene seemed to be constitutively expressed. To detect the pattern change of SLC17A1 in survival AML cells against Ara-C treatments, four AML cell-lines underwent 10−8 M of Ara-C addition/ depletion for 2 and 4 cycles. The results showed that expression of SLC17A1 was decreased more than SLC29A1 expression in the same treated condition. To examine whether the expression levels of SLC17A1 was associated with Ara-C resistance, Ara-C resistant HEL cell was established in vitro and in vivo (HEL-R1 and HEL-R1-vivo). Our results indicated that SLC17A1 mRNA expression of both resistant cells is decreased or less increased than HEL cells in Ara-C treatment. And the reduction of SLC17A1 mRNA by shRNA of SLC17A1 effectively suppressed Ara-C mediated apoptosis. Our results suggested that the function of SLC17A1 gene was similar to that of SLC29A1. Taken together, the expression levels of SLC17A1 also might involve the cytotoxic effects of Ara-C treatment. SLC17A1 could be a novel gene controlling Ara-C mediated apoptosis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3540.

Autoantibodies to glucose‐6‐phosphate isomerase are elevated in the synovial fluid of rheumatoid arthritis patients

OBJECTIVE

This study investigated whether anti-glucose-6-phosphate isomerase (GPI) antibody in the synovial fluid is specifically related to human rheumatoid arthritis (RA).

METHODS

Synovial fluid was collected from patients with RA, osteoarthritis (OA), gout, Behcet's disease, or ankylosing spondylitis. GPI-binding activity was measured in the synovial fluid using a surface plasmon resonance (SPR) biosensor.

RESULTS

The mean level of anti-GPI signal in the synovial fluid of RA patients was significantly elevated compared with that of OA patients (2.84 +/- 1.41 AU versus 1.19 +/- 0.42 AU, respectively; p < 0.0001). Anti-GPI signals in the synovial fluids of patients with non-rheumatoid arthritis, such as gout, Behcet's disease, or ankylosing spondylitis were significantly lower than in the synovial fluid of RA patients (p < 0.005), and were similar to those of OA patients.

CONCLUSION

Our study indicates that anti-GPI antibody in the synovial fluid is specifically related to RA, and suggests that GPI and its autoantibody might be important in the pathogenesis of human RA.

Non-A type nucleophosmin 1 gene mutation predicts poor clinical outcome in de novo adult acute myeloid leukemia: differential clinical importance of NPM1 mutation according to subtype

Mutations of nucleophosmin gene (NPM1) are known to be related to good prognosis in AML patients lacking FLT3 internal tandem duplication (FLT3-ITD). Recently, NPM1 mutations other than type A were reported, but their clinical significance is not well known. Retrospective medical record review of 106 de novo AML patients lacking FLT3-ITD, who received induction chemotherapy from three centers in Korea between 1997 and 2007, was performed. Direct sequencing of NPM1 and RT-PCR for FLT3-ITD was performed on genomic DNA derived from blood samples of patients before induction chemotherapy for detection of mutations. NPM1 mutation was detected in 18 patients, where 13 were type A mutants and 5 were non-type A mutants. CR, CR1-D and OS was not different according to NPM1 mutational status overall. But, non-type A NPM1 mutation was related to shorter CR1-D when compared with NPM1 wild types and NPM1 type A mutation (p = 0.004). OS was shorter in non-type A mutants when compared with NPM1 wild-type patients and NPM1 type A mutants (p = 0.001). The type of mutation of NPM1 is important for prognosis in de novo AML lacking FLT3-ITD. Non-A type NPM1 mutation is a poor prognostic factor.

Patency of splenic vessels after laparoscopic spleen and splenic vessel-preserving distal pancreatectomy

Background

This study evaluated the short- and long-term patency of preserved splenic vessels after laparoscopic spleen-preserving distal pancreatectomy (SPDP) with preservation of the splenic vessels.

Methods

This single-centre retrospective study included all patients who had undergone splenic vessel-preserving laparoscopic SPDP between 2004 and 2007. The patency of the splenic vessels was assessed by abdominal computed tomography and classified into three grades according to the degree of stenosis.

Results

Twenty-two patients were included. The preoperative patency of the splenic artery and vein was normal in 20 and 19 patients respectively. Normal patency of the splenic artery and vein was observed in 16 and five patients respectively within 1 month of surgery, and in 19 and nine patients 6 months or more after operation. Nine of ten patients with complete splenic vein occlusion developed a collateral circulation in the late postoperative phase. Splenic perfusion was well preserved in all patients.

Conclusion

Splenic vessel-preserving laparoscopic SPDP has the short-term benefit of good perfusion to the spleen. In the long term, there is a risk of left-sided portal hypertension if the splenic vein becomes occluded after surgery.

Different clinical importance of FLT3 internal tandem duplications in AML according to FAB classification: possible existence of distinct leukemogenesis involving monocyte differentiation pathway

Impact of FLT3 receptor tyrosine kinase activation via internal tandem duplication (ITD) of the juxtamembrane region on outcome of acute myeloid leukemia (AML) is still controversial. Recent researches reveal a role of FLT3 in monocyte differentiation in hematopoiesis. We analyzed the clinical impact of FLT3 alterations in adult AML patients excluding acute promyelocytic leukemia (APL) who received induction chemotherapy according to morphologic classification. Retrospective review of medical records from three centers in Korea between 1997 and 2007 was performed. Polymerase chain reaction was performed on genomic DNA derived from blood samples of patients before induction chemotherapy for FLT3-ITD detection. We assessed overall survival (OS), first disease-free survival (1-DFS), and response to induction chemotherapy. One hundred eighty-four patients (median age 49.1 years, range 16.0-76.5) with AML excluding APL received induction chemotherapy from three centers. FLT3-ITD was detected in 22 patients. One hundred forty-one patients were below age 60. One hundred seventy-nine patients received induction chemotherapy with cytarabine and idarubicin (AId) regimen. One hundred nineteen patients achieved complete remission (CR) after first induction chemotherapy. FLT3-ITD was not related to achievement of CR. 1-DFS was longer in patients without FLT3-ITD (median 1-DFS 16.5 vs. 8.5 months, p = 0.025). 1-DFS was not different according to FLT3-ITD status in nonmonocyte lineage leukemia (p = 0.355), while 1-DFS was shorter in monocyte lineage leukemia for FLT3-ITD positive patients (20.9 vs. 2.4 months, p < 0.001). FLT3-ITD had no impact on OS except for monocyte lineage, where OS was significantly shorter in FLT3-ITD positive group (39.4 vs. 6.0 months, p = 0.026). Moreover FLT3-ITD was stronger prognostic factors in monocyte lineage AML than risk stratification based on cytogenetics. Status of FLT3-ITD should be analyzed differently in AML patients according to morphologic profile. FLT3-ITD is a predictive and prognostic marker only in monocyte lineage patients. This result suggests an existence of distinct subset of monocyte lineage AML with leukemogenesis involving FLT3 activating pathway.

Case of adult mumps infection after renal transplantation

Viruses are the most common cause of opportunistic infections, important complications of transplantation. Mumps infection in renal transplant recipients is uncommon. This report focused on a 23-year-old woman who received immunosuppressive therapy based on tacrolimus, prednisolone, and mycophenolate mofetil for renal transplantation. Sixteen months after transplantation, she was admitted with pain and swelling in both infra-auricular areas. Laboratory findings demonstrated positive mumps IgM and IgG antibodies and an increased serum amylase level. Computed tomography revealed both parotid glands to be diffusely enlarged. After the diagnosis of mumps parotitis, the patient's immunosuppression was reduced and the clinical course was satisfactory.

Curcumin in combination with bortezomib synergistically induced apoptosis in human multiple myeloma U266 cells

Growth of multiple myeloma cells is controlled by various factors derived from host bone marrow microenvironments. Interaction between multiple myeloma cells and bone marrow stromal cells (BMSCs) plays an important role in the expression of adhesive molecules and secretion of growth factors involved in multiple myeloma (MM) cell growth, survival, and resistance to anticancer drugs. Recently, the possibility of developing novel anti-cancer therapeutic strategies targeting both MM cells and MM cell-BMSC interactions has been discussed. Here we present data showing that curcumin, a major constituent of turmeric compounds extracted from the rhizomes of the plant Curcuma longa, effectively reduced the growth of MM cells and BMSCs. Upon treatment with curcumin, IL-6/sIL-6R-induced STAT3 and Erk phosphorylation was dramatically reduced in the co-cultured cells. In addition, curcumin inhibited the production of pro-inflammatory cytokines and VEGF, factors that are associated with the progression of multiple myeloma, from both MM cells and BMSCs. In a combination treatment with curcumin and bortezomib, IL-6/sIL-6R-induced STAT3 and Erk phosphorylation was effectively inhibited. Moreover, this combination treatment synergistically inhibited the growth of MM cells co-cultured with BMSCs as compared to controls. Taken together, these results indicate that curcumin potentiates the therapeutic efficacy of bortezomib in MM suggesting this combination therapy to be of value in the clinical management of MM.

Combination of SK-7041, one of novel histone deacetylase inhibitors, and STI571-induced synergistic apoptosis in chronic myeloid leukemia

Although STI571 still plays a key role in the treatment of chronic myeloid leukemia, emergence of resistance to STI571 is a major obstacle to successful outcome. Therefore, new agents that increase the sensitivity of chronic myeloid leukemia cells to STI571 are urgently required. SK-7041 is a novel hybrid synthetic histone deacetylase inhibitor derived from the hydroxamic acid of trichostatin A and pyridyl ring of MS-275. Its cytotoxic effects were examined both as a single agent and in combination with STI571 in acute and chronic myeloid leukemia. SK-7041 exhibited growth inhibition of leukemia cells by downregulation of CDK4, cyclin E and cyclin B1 expression, and by upregulation of p21 expression with subsequent activation of the mitochondria-mediated caspase pathway. SK-7041 showed synergism on growth inhibition, cell cycle arrest and induction of apoptosis in chronic myeloid leukemia (K562) when combined with STI571. The synergistic effect was mediated through the same mechanism as in SK-7041 alone, involving reduction of cyclin D1 and induction of p21. Taken together, our findings suggest that SK-7041 is active against leukemia and offers new prospects for overcoming STI571 resistance in chronic myeloid leukemia.

Microenvironment effects on promoting upregulation of matrix metalloproteinases in Bcl-2-overexpressing renal cell carcinoma as a response to doxorubicin treatment inducing the production of metastasis

Dysfunction in apoptosis has been suggested to play an important role in the development of a distant metastasis. The Bcl-2 gene plays a key role in the response to chemotherapeutic agents, and its upregulation protects the cells from apoptosis by inactivating the Bax proteins through heterodimerization of Bcl-2/Bax. However, there is no direct evidence showing that the upregulation of Bcl-2 increases the antiapoptotic effects against chemotherapeutic agents and is associated with the production of a distant metastasis. In this study, the role of Bcl-2 in the production of distant metastasis was investigated by examining the activity of caspase-3 and the expression of matrix metalloproteinases (MMPs) after transfecting the Bcl-2 gene into human renal cell carcinoma cells (SN12C). In addition, the production of a distant metastasis was examined in an orthotopic animal model. In vitro, the SN12C/smb2 cells were more resistant to doxorubicin (DXR) than the untreated parental cells. The IC50 of the SN12C/smb2 was 50% higher than that of the parental cells. In addition, the caspase-3 activity of the SN12C/smb2 cells was lower than that of the parental cells after the DXR treatment. On the other hand, there was no difference in the expression of MMP-2 and MMP-9 between the SN12C and SN12C/smb2 cell lines. However, the SN12C/smb2 cells had a higher metastatic potential than the parental cells in the orthotopic animal model. Unlike the results from the in vitro analysis, the expression of MMP-2 and MMP-9 in the kidney tumors produced by the SN12C/smb2 cells was higher than in the kidney tumors produced by the SN12C/vector. These results show that the upregulation of Bcl-2 in human renal cell carcinoma cells induces drug resistance to DXR. Moreover, Bcl-2 induced the expression of MMP in tumors grown in the orthotopic sites even though no appreciable effects were observed in the in vitro condition. When the in vitro and in vivo data were combined, it appears that the Bcl-2 gene initially affects the response to DXR. The cells that survive the DXR treatment then have a chance to become metastatic by increasing the levels of MMP in an orthotopic environment.

Epidermal growth factor (EGF) activates nuclear factor-κB through IκBα kinase-independent but EGF receptor-kinase dependent tyrosine 42 phosphorylation of IκBα

Overexpression of epidermal growth factor (EGF) receptor and constitutive activation of nuclear factor-kappaB (NF-kappaB) are frequently encountered in tumor cells. Although EGF has been shown to induce NF-kappaB activation, the mechanism is poorly understood. EGF activated NF-kappaB DNA binding, induced NF-kappaB reporter activity and the expression of antiapoptotic and cell-proliferative gene products. Interestingly, non-small cell lung adenocarcinoma cell lines (HCC827 and H3255), which exhibit EGFR amplification, showed ligand-independent activation of NF-kappaB. Unlike tumor-necrosis factor (TNF), however, EGF failed to induce IkappaBalpha phosphorylation and ubiquitination and the activation of IkappaBalpha kinase (IKK). Although DN-IKKbeta inhibited TNF-induced NF-kappaB activity, DN-IKKbeta had no effect on EGF-induced NF-kappaB activation, suggesting that EGF-induced NF-kappaB activation is IKK independent. Using dominant-negative plasmids, we also demonstrated the role of TRADD, TRAF2, NIK and Ras in EGF-induced NF-kappaB activation. By using specific antibodies and IkappaBalpha plasmid, which is mutated at tyrosine 42 to phenylalanine, we show that EGF induced the tyrosine phosphorylation of IkappaBalpha at residue 42. Furthermore, EGF receptor kinase inhibitor blocked IkappaBalpha phosphorylation and consequent NF-kappaB activation. Overall, our results indicate that tyrosine phosphorylation of IkappaBalpha at residue 42 is critical for EGF-induced NF-kappaB activation pathway.

Tumor necrosis factor-alpha induces vascular endothelial growth factor-C expression in rheumatoid synoviocytes

OBJECTIVE

To determine the expression of vascular endothelial growth factor-C (VEGF-C) in the synovial fluid of patients with rheumatoid arthritis (RA) and to investigate the regulation of VEGF-C production by major proinflammatory cytokines in fibroblast-like synoviocytes (FLS).

METHODS

The concentrations of VEGF-C, tumor necrosis factor-alpha (TNF-alpha), and interleukin 1beta (IL-1beta) were measured using an ELISA method in synovial fluids obtained from 20 patients with RA and 20 with osteoarthritis (OA). Primary cultured RA FLS were stimulated with TNF-alpha or IL-1beta, and the expression levels of VEGF-C mRNA and protein were assessed by quantitative real-time polymerase chain reaction and ELISA.

RESULTS

Significantly higher levels of VEGF-C were found in RA synovial fluids compared to OA synovial fluids. VEGF-C levels showed a highly significant correlation with the levels of both TNF-alpha and IL-1beta in the synovial fluid of patients with RA. TNF-alpha stimulation significantly increased VEGF-C mRNA and protein expression in RA FLS in a dose-dependent manner. A tendency to increased expression of VEGF-C was also observed after IL-1beta stimulation in FLS.

CONCLUSION

Overexpression of VEGF-C in FLS by stimulation with TNF-alpha may play an important role in the progression of synovial inflammation and hyperplasia in RA by contributing to local lymphangiogenesis and angiogenesis.

The effects of curcumin on the invasiveness of prostate cancer in vitro and in vivo

Curcumin has become a focus of interest with regard to its antitumor effects in prostate cancer; however, the effects of this agent on invasion and metastasis remain less well understood. Matrix metalloproteinases (MMPs) are important prerequisite for tumor invasion and metastasis. In this study, we evaluated the effects of curcumin on prostate cancer cells (DU-145) invasion in both in vitro and in vivo. We utilized zymography and ELISA in order to determine the MMP-2 and MMP-9 activity. Matrigel invasion assay was performed to assess cellular invasion. We developed a xenograft model to examine tumorigenicity. Curcumin treatment resulted not only in a significant reduction in the expression of MMP-2 and MMP-9, but also effected the inhibition of invasive ability in vitro. Curcumin was shown to induce a marked reduction of tumor volume, MMP-2, and MMP-9 activity in the tumor-bearing site. The metastatic nodules in vivo were significantly fewer in the curcumin-treated group than untreated group. Curcumin appears to constitute a potential agent for the prevention of cancer progression, or at least of the initial phase of metastasis, in prostate cancer.

TNF blockade: an inflammatory issue

Tumor necrosis factor (TNF), initially discovered as a result of its antitumor activity, has now been shown to mediate tumor initiation, promotion, and metastasis. In addition, dysregulation of TNF has been implicated in a wide variety of inflammatory diseases including rheumatoid arthritis, Crohn's disease, multiple sclerosis, psoriasis, scleroderma, atopic dermatitis, systemic lupus erythematosus, type II diabetes, atherosclerosis, myocardial infarction, osteoporosis, and autoimmune deficiency disease. TNF, however, is a critical component of effective immune surveillance and is required for proper proliferation and function of NK cells, T cells, B cells, macrophages, and dendritic cells. TNF activity can be blocked, either by using antibodies (Remicade and Humira) or soluble TNF receptor (Enbrel), for the symptoms of arthritis and Crohn's disease to be alleviated, but at the same time, such treatment increases the risk of infections, certain type of cancers, and cardiotoxicity. Thus blockers of TNF that are safe and yet efficacious are urgently needed. Some evidence suggests that while the transmembrane form of TNF has beneficial effects, soluble TNF mediates toxicity. In most cells, TNF mediates its effects through activation of caspases, NF-kappaB, AP-1, c-jun N-terminal kinase, p38 MAPK, and p44/p42 MAPK. Agents that can differentially regulate TNF expression or TNF signaling can be pharmacologically safe and effective therapeutics. Our laboratory has identified numerous such agents from natural sources. These are discussed further in detail.

Cyclophilin A may contribute to the inflammatory processes in rheumatoid arthritis through induction of matrix degrading enzymes and inflammatory cytokines from macrophages

Cyclophilin A (CypA) levels increase in the sera and synovial fluids of rheumatoid arthritis (RA) patients, but the cell types expressing CypA and the function of CypA in the pathogenesis of RA are not known yet. Immunohistochemistry analyses revealed high level CypA staining in the macrophages in the lining layers of human RA and osteoarthritis synovium. Low level CypA staining was also detected in endothelial cells, lymphocytes, and smooth muscle cells in RA synovium. Further investigation of the CypA function using monocyte/macrophage cell lines revealed that CypA induced expression of cytokine/chemokines such as TNF-alpha, IL-8, MCP-1, and IL-1beta and matrix metalloproteinase (MMP)-9 through a pathway that is dependent on NFkappaB activation. Furthermore, MMP-9 staining pattern overlapped with that of CypA in both RA and OA synovium. Our data suggest that CypA may stimulate macrophages to degrade joint cartilage via MMP-9 expression and promote inflammation via pro-inflammatory cytokine secretion.

LIGHT is involved in the pathogenesis of rheumatoid arthritis by inducing the expression of pro-inflammatory cytokines and MMP-9 in macrophages

Macrophages play a crucial role in the perpetuation of inflammation and irreversible cartilage damage during the development of rheumatoid arthritis (RA). LIGHT (TNFSF14) and its receptor TR2 (TNFRSF14) are known to have pro-inflammatory activities in foam cells of atherosclerotic plaques. We tested a hypothesis that LIGHT and TR2 are involved in activation of monocyte/macrophages in RA synovium. Immunohistochemical analysis of RA synovial tissue samples revealed that both LIGHT and TR2 are expressed in CD68 positive macrophages. In contrast, synovial tissue samples from osteoarthritis (OA) patients failed to reveal the expression of LIGHT. Expression of TR2 in RA synovial macrophages was also detected using flow cytometry analysis. To identify the role of LIGHT in the functioning of macrophages in RA, we isolated macrophage enriched cells from RA synovial fluid and stimulated them with LIGHT. LIGHT induced expression of matrix metalloproteinase-9 and pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8. These data indicate that LIGHT and TR2 expressed in macrophages are involved in the pathogenesis of RA by inducing the expression pro-inflammatory cytokines and matrix degrading enzymes.

Identification of calcium-inducible genes in primary keratinocytes using suppression-subtractive hybridization

Terminal differentiation in epidermal keratinocytes involves major biochemical changes including the expression of many new differentiation-specific genes. To further understand this process, we performed suppression-subtractive hybridization of keratinocytes cultured under high-calcium condition, known to induce differentiation in vitro. We randomly isolated 300 clones representing 90 different genes. By reverse Northern blot analyses, 20 different genes were found to be overexpressed, of which 13 were confirmed as differentially expressed genes during keratinocyte differentiation by Northern blot analysis. Of those, five genes, transglutaminase 1, keratin 6, interleukin-1 receptor antagonist, kallikrein 7, and heat shock protein 27, are known to be up-regulated during epidermal differentiation. Six genes, ferritin-L chain, ribosomal protein S6, tumor-associated calcium signal transducer 2, neuroendocrine secretory protein 55, phosphoserine aminotransferase, and neutrophil gelatinase-associated lipocalin, heretofore were not known to be up-regulated during keratinocyte differentiation. We also identified two novel genes. One of these maps to chromosome 1q21 of the epidermal differentiation complex, and its expression level was strongly increased in differentiating keratinocytes. These differentially expressed genes may provide significant opportunities for further understanding of the epidermal keratinocyte differentiation.

Inhibitory effect of cyclo-oxygenase-2 inhibitor on the production of matrix metalloproteinases in rheumatoid fibroblast-like synoviocytes

Cyclo-oxygenase (COX)-2 has been associated with inflammation in rheumatoid arthritis (RA), but its role in joint destruction remains unclear. In this study, we investigated the effect on cultured rheumatoid fibroblast-like synoviocytes (FLS) of the selective COX-2 inhibitor celecoxib on the expression of matrix metalloproteinases (MMPs), which play an important role in tissue degradation and angiogenesis in rheumatoid synovium. Treatment with nontoxic doses of celecoxib resulted in dose-dependent inhibition of MMP-1, -2, and -3 secretion from FLS when measured by enzyme-linked immunosorbent assay. Celecoxib suppressed proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta) induced augmentation of the gelatinolytic activity on zymography. These results suggest that COX-2 inhibitors might influence matrix degradation or angiogenesis in RA by downregulating the expression of various MMPs in rheumatoid FLS.

Keratin 9 gene mutations in five Korean families with epidermolytic palmoplantar keratoderma

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant disease characterized clinically by localized palmoplantar thickening and histopathologically by granular degeneration of the epidermis. Recent molecular biological studies have revealed that EPPK is caused by mutations of the keratin 9 gene in sequences mainly encoding the highly conserved 1 A rod domain. Here we demonstrate a novel mutation of N160H (position 8 of the 1 A domain) and two other previously reported mutations, R162W and N160S, in five unrelated Korean families with EPPK. The three-dimensional structure of the 1 A domain of the related vimentin intermediate filament protein chain is now known. Based on its likely similarity to the keratin 9 chain, we predict that inappropriate amino acid substitutions in position 10 of 1 A will likely interfere with coiled-coil dimer stability, and those in position 8 will interfere with tetramer stability. Accordingly, these mutations compromise the structural integrity of the keratin intermediate filaments leading to the pathology of EPPK.

Influence of hypoxia on the expression of matrix metalloproteinase-1, -3 and tissue inhibitor of metalloproteinase-1 in rheumatoid synovial fibroblasts

OBJECTIVE

The rheumatoid synovium is a hypoxic environment, and hypoxia has been implicated as a factor in the pathogenesis of rheumatoid arthritis (RA). The purpose of this study was to investigate the effect of hypoxia on the expression of matrix metalloproteinase (MMP)-1, -3 and tissue inhibitor of metalloproteinase (TIMP)-1 in rheumatoid synovial fibroblasts.

METHODS

Synovial fibroblasts obtained from RA patients were cultured for 48 h under normoxic or hypoxic conditions. Assays included western blot analysis and enzyme-linked immunosorbent assay (ELISA) for MMP-1, -3 and TIMP-1, and northern blot analysis to measure TIMP-1 mRNA levels.

RESULTS

Compared with normoxic culture, hypoxia increased MMP-1 and MMP-3 expression in rheumatoid synovial fibroblasts. Hypoxia decreased TIMP-1 expression in rheumatoid synovial fibroblasts, as measured by both protein and mRNA levels.

CONCLUSION

These results suggest that microenvironmental conditions, such as hypoxia, may directly contribute to joint destruction in RA by increasing the ratio of MMP-1, -3 to TIMP-1 production in synovial fibroblasts.

Effects of Korean red ginseng and its mixed prescription on the high molecular weight dextran-induced blood stasis in rats and human platelet aggregation

This study was undertaken to evaluate the antithrombotic effects of Korean Red Ginseng (KRG) and its new prescription (KRGP) consisting of five herbs such as Korean red ginseng, Ganoderma, Cinnamomi Cortex, Glycyrrhizae Radix and Laminaria. In rats with blood stasis induced by high molecular weight dextran, KRG and KRGP significantly restored not only the number of platelets and fibrinogen, but also suppressed the fibrin degradation products (FDP) to normal range. In platelet aggregation assay with human platelet rich plasma (PRP), KRG and KRGP significantly inhibited thrombin and collagen-induced platelet aggregation. The IC(50) values of KRG and KRGP were >2 and 0.23+/-0.01 mg/ml for thrombin, 0.32+/-0.01 and 0.17+/-0.02 mg/ml for collagen and 0.72+/-0.25 and >2 mg/ml for ADP, respectively. In coagulation assay, KRG and KRGP significantly prolonged activated partial prothrombin time (APPT) and prothrombin time (PT) as compared with control data. KRGP was found to be more effective than KRG alone on antithrombotic activity. These results suggest that KRGP may exert its antithrombotic activity due to inhibition of platelet aggregation and coagulation activity more than KRG.