A Case of Vesiculobullous Dermatomyositis with Anti-NXP-2 Antibody without Malignancy.

Vesiculobullous dermatomyositis (VD) is a rare manifestation of dermatomyositis (DM) and has been suggested to be associated with malignancy. Although the myositis-specific autoantibodies are associated with distinct clinical presentations of DM, those associated with VD remain unclear. Here, we present the case of a 54-year-old man with VD who tested positive for anti-nuclear matrix protein 2 (NXP-2) antibody, one of the DM-specific autoantibodies. Serological and histopathological findings did not support autoimmune blistering disease. Physical and histological findings suggested that the severe edema in combination with the interface dermatitis of DM contributed to blister formation. Although a systemic examination was performed, no evidence of malignancy was found. Following initiation of immunosuppressive therapy, the patient showed significant improvement in both skin lesions and myositis. This case represents the first report of anti-NXP-2-positive VD without malignancy or autoimmune blistering disease. Subcutaneous edema, a characteristic feature of anti-NXP-2-positive DM, could be related to the formation of VD.

Differences in the autoantibody phenotypes and long-term outcomes between juvenile- and adult-idiopathic inflammatory myopathies.

OBJECTIVE: To investigate differences in autoantibodies, clinical features, and long-term outcomes between juvenile-idiopathic inflammatory myopathy (IIM) and adult-IIM METHODS: Autoantibodies, clinical characteristics, and drug-free conditions for a maximum of 20 years were retrospectively analyzed in 320 Japanese IIM patients (juvenile-IIM, n = 34; adult-IIM, n = 286) using the Kyoto University Registry. RESULTS: Autoantibodies observed in juvenile-IIM were anti-TIF1-γ (15 %), anti-MDA-5 (15 %), anti-ARS (9 %), and anti-NXP-2 (6 %). Those observed in adult-IIM were anti-ARS (32 %), anti-MDA-5 (23 %), anti-TIF1-γ (8 %), anti-SRP (8 %), anti-Mi-2 (2 %), and anti-NXP-2 (1 %). The cumulative drug-free condition rate was higher in juvenile-IIM than in adult-IIM up to 20 years (juvenile-IIM vs. adult-IIM, 34 % vs. 18 %, p = 0.0016). Anti-TIF1-γ was associated with lesser muscle symptoms (60 % vs. 90 %), malignancy (0 % vs. 57 %), and glucocorticoid use (40 % vs. 86 %) in juvenile-IIM compared to adult-IIM, while juvenile-IIM more achieved drug-free conditions (60 % vs. 25 %). Both juvenile-IIM and adult-IIM with anti-MDA-5 demonstrated a high frequency of amyopathic dermatomyositis, interstitial lung disease (ILD), and multi-immunosuppressive therapy, with high drug-free conditions (50 % vs. 49 %). Both juvenile-IIM and adult-IIM with anti-ARS showed frequent skin rashes, muscle symptoms, and ILD, frequent need for multi-immunosuppressive therapy, and low drug-free condition rates (0 % vs. 3 %). Both juvenile-IIM and adult-IIM with anti-NXP-2 showed frequent skin rashes and muscle symptoms, low ILD frequency, and frequent use of methotrexate and glucocorticoids, which did not achieve drug-free conditions (0 % vs. 0 %). CONCLUSIONS: Drug-free condition was achieved more frequently in juvenile-IIM patients than adult-IIM patients. Specific autoantibodies were associated with different clinical characteristics and outcomes between juvenile-IIM and adult-IIM.

TAFRO syndrome is associated with anti-SSA/Ro60 antibodies, in contrast to idiopathic castleman disease.

TAFRO syndrome is an acute systemic inflammatory disease characterized by thrombocytopenia, anasarca, fever, reticulin fibrosis/renal dysfunction, and organomegaly. There have been increasing reports that TAFRO is a disease distinct from idiopathic multicentric Castleman disease and that TAFRO patients may be positive for anti-SSA antibodies. To assess anti-SSA antibody positivity and the clinical characteristics of the two diseases, we retrospectively compared 7 TAFRO and 10 iMCD patients in our hospital. The mean age of onset of TAFRO and iMCD was 48.0 (interquartile range [IQR], 41-53) and 45.0 (IQR, 35-53) years, respectively. The TAFRO and iMCD groups had 6 (86%) and 4 (40%) male patients, respectively, and the following pretreatment laboratory values: platelet count, 3.8 (IQR, 2.2-6.4) and 35.5 (IQR, 22.2-42.8) × 104/µL, respectively; C-reactive protein, 10.2 (IQR, 6.8-21.4) and 9.5 (IQR, 6.2-13.6) mg/dL, respectively; IgG, 1431 (IQR, 1112-1815) and 4725 (IQR, 3755-5121) mg/dL, respectively. RNA immunoprecipitation (5 cases for anti-SSA) or protein array (5 cases for anti-SSA/Ro60) detected anti-SSA antibodies in six (86%) TAFRO patients but not in iMCD patients; it did not detect anti-SSB antibodies in any of the patients. None of the patients were diagnosed with Sjögren syndrome. All iMCD patients treated with tocilizumab (TCZ) responded well. Meanwhile, two of six TAFRO patients treated with TCZ showed inadequate responses; thus, both patients were switched to rituximab, following which they achieved remission. TAFRO and iMCD have different clinical features. TAFRO may be categorized as a severe phenotype of the anti-SSA antibody syndrome.

A case of atypical IgG4-related disease presenting hypereosinophilia, polyneuropathy, and liver dysfunction.

Ig (immunoglobulin) G4-related disease (Ig4-RD) affects several organs, including salivary glands, lacrimal glands, pancreas, biliary ducts, and retroperitoneum. A 72-year-old woman was examined for hypereosinophilia, high levels of IgG4, polyneuropathy, liver dysfunction, enlargement of lymph nodes and lacrimal glands, and beaded dilation of the bile ducts. We diagnosed Ig4-RD based on biopsies of the lymph nodes, liver, and submandibular gland. The symptoms of the patient improved after glucocorticoid treatment. This was a novel and atypical case of Ig4-RD that was difficult to differentiate from other diseases, including eosinophilic granulomatosis with polyangiitis, idiopathic hypereosinophilic syndrome, and polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes syndrome. This case report highlights the importance of biopsies in differentiating Ig4-RD.

Long-Term Prognosis of Antimelanoma Differentiation-Associated Gene 5-Positive Dermatomyositis With Interstitial Lung Disease.

OBJECTIVE: Antimelanoma differentiation-associated gene 5 (anti-MDA5)-positive dermatomyositis with interstitial lung disease (DM-ILD) progresses rapidly and has a poor prognosis. Previously, we reported the efficacy of a combination therapy comprising high-dose glucocorticoids (GCs), calcineurin inhibitors (CNIs), and intravenous cyclophosphamide (IV CYC) in a multicenter clinical trial (UMIN000014344). In the present study, we evaluated the long-term outcomes and effects of induction therapy on the maintenance of remission. METHODS: All participants from our previous trial were followed up for > 5 years. Seventy-three other patients with anti-MDA5-positive DM-ILD from our institute were retrospectively integrated into the previous trial for further analysis. Sixty-eight patients achieved remission and survived for > 6 months. Based on the induction treatment, we classified the patients into 2 groups: (1) group T (n = 56), with triple combination therapy (GCs, CNIs, and IV CYC), and (2) group C (n = 12), with monotherapy/dual therapy. The recurrence-free and drug-withdrawal rates of immunosuppressive agents were compared. RESULTS: The overall survival and recurrence-free survival rates at 5 years were 100% for the participants in the previous trial. The 5-year cumulative withdrawal rates for CNIs and GCs were 70% and 53%, respectively. In a comprehensive analysis, the recurrence-free rates in group T were higher than those in group C (90% vs 56%; P < 0.05). The drug-withdrawal rates of CNIs and GCs at 10 years in group T were also higher than those in group C (79% vs 0% and 43% vs 0%, respectively; P < 0.05). CONCLUSION: Triple combination therapy in the induction phase can reduce the risk of recurrence and facilitate drug withdrawal in anti-MDA5-positive DM-ILD.

Rheumatoid factor recognizes specific domains of the IgG heavy chain complexed with HLA class II molecules.

OBJECTIVE: We previously reported that RF recognized the IgG heavy chain (IgGH)/RA-susceptible HLA class II molecule complex. In the present study, we investigated the molecular mechanisms underlying HLA binding to and the RF recognition of IgGH. METHODS: We synthesized various types of IgGH segments, including VH, CH1, CH2 and CH3, and transfected them with or without HLA class II molecules into the Human Embryonic Kidney 293T cell line. IgGH single domains linked with the HLA-Cw3 peptide, which binds to the binding groove of the HLA class II molecule, were also synthesized. The expression of IgGH domains on the cell surface and their recognition by RF were examined using flow cytometry. RESULTS: Flag-tagged IgGH segments containing CH1 (CH1, VH-CH1, CH1-CH2, VH-CH1-CH2, CH1-CH2-CH3 and VH-CH1-CH2-CH3) were clearly presented on the cell surface by HLA-DR4, while segments without the CH1 domain were expressed at a low level, and the CH3 single domain was only weakly detected on the cell surface, even with HLA-DR4. We then transfected IgGH single domains linked to the Cw3 peptide together with HLA-DR4 and showed that RF-containing sera from RA patients only recognized the CH3 domain and none of the other single domains. When various segments without the Cw3 peptide were transfected with HLA-DR4, only the CH1-CH2-CH3 segment and full-length IgGH were detected by the sera of RA patients. CONCLUSION: The CH1 domain of IgGH binds to the RA-susceptible HLA-DR molecule and is expressed on the cell surface. RF specifically recognizes the CH3 domain of the IgGH/HLA-DR4 complex.

Primary hepatic lymphoma as other iatrogenic immunodeficiency-related lymphoproliferative disorders: a case report and review of the literature.

We report a case of 68-year-old man with stable polymyositis complicated with primary hepatic lymphoma (PHL) as other iatrogenic immunodeficiency-related lymphoproliferative disorders (OIIA-LPD). Multiple liver masses were diagnosed as diffuse large B-cell lymphoma (DLBCL) by biopsy. The LPD was associated with Epstein-Barr virus (EBV) reactivation, because EBV-DNA was detected in peripheral blood, and EBV antigen was detected in the tumour. He presented with high fever, cytopenia and hyperferritinemia, suggesting hemophagocytosis. Only discontinuation of methotrexate and tacrolimus resulted in a dramatic regression of the liver masses and improvement of fever and cytopenia. We review six cases of OIIA-LPD localised in the liver. All cases were DLBCL; 4/6 cases (67%) were positive for EBV staining, and 2/6 cases (33%) were improved after the discontinuation of immunosuppressants. Screening for EBV in blood and liver tumour is important, when a patient in immunosuppressive status presented with liver masses.

Case report of API2-MALT1 fusion-positive MALT lymphoma arising from bilateral submandibular glands with no evidence of autoimmune syndromes.

Mucosa-associated lymphoid tissue (MALT) lymphoma arising from the salivary glands is usually associated with chronic infection or autoimmune syndromes, such as primary Sjogren syndrome. The occurrence of t(11;18)/API2-MALT1 is rare in salivary MALT lymphoma. Here we describe a case of API2-MALT1 fusion-positive MALT lymphoma of the bilateral submandibular glands with no evidence of autoimmune syndromes. A 70-year-old man complained of a painless swelling in the bilateral submandibular gland. Serology examination results were negative for anti-SSA and anti-SSB. His right submandibular gland was dissected, and he was diagnosed with MALT lymphoma with the API2-MALT1 fusion gene. Positron emission tomography/computed tomography scanning indicated mild fluorine-18-fluorodeoxyglucose uptake in the left submandibular gland and liver. He was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone. After 6 years, the patient is alive and disease free. In the present case, the patient with API2-MALT1 fusion-positive MALT lymphoma had a good outcome despite the advanced clinical stage.

Efficacy of plasma exchange in anti-MDA5-positive dermatomyositis with interstitial lung disease under combined immunosuppressive treatment.

OBJECTIVES: Rapidly progressive interstitial lung disease (RP-ILD) with poor prognosis often accompanies anti-melanoma differentiation-associated gene 5 (MDA5)-positive DM. Combined immunosuppressive therapy, including glucocorticoids, calcineurin inhibitors and intravenous cyclophosphamide (IVCY) is reportedly effective in DM with RP-ILD, but some patients remain resistant to therapy. We examined the utility of plasma exchange (PE) in such intractable cases and investigated the prognostic factors of the disease. METHODS: Thirty-eight anti-MDA5-positive DM-ILD patients who received the combined immunosuppressive therapy were retrospectively reviewed. Their serum cytokines were evaluated by multiplex assay before treatment. The patients were divided into two groups: those who achieved remission without exacerbation of respiratory dysfunction (n = 25, group A) and those who progressed to hypoxemia during the treatment (n = 13, group B). RESULTS: PE was carried out in eight group B patients, but none of group A. Five of the eight treated with PE survived, while the five untreated patients died (P =0.04). Higher neutrophil lymphocyte ratio, higher serum ferritin, hypoxemia, high-resolution computed tomography (HRCT) score before treatment and increase of Krebs von Lungen-6 (KL-6) in the first 4 weeks of the treatment were the prognostic factors for disease progression. Serum cytokines such as IL-1, IL-6, IL-8, IL-10, IL-12p70, IL-18 and sCD163 levels were higher in group B than group A. CONCLUSION: PE should be an effective adjuvant treatment in anti-MDA5-positive DM with RP-ILD. Assessment of basal laboratory tests or monocyte/macrophage-derived cytokines and the increase of KL-6, HRCT score and hypoxemia may help us to predict intractable cases and to make early treatment decisions regarding PE in anti-MDA5-positive DM.

Persistent anemia and hypoalbuminemia in rheumatoid arthritis patients with low serum triiodothyronine level.

Objectives: To determine the clinical characteristics of rheumatoid arthritis (RA) patients with low serum triiodothyronine (T3) levels.Methods: We evaluated serum free T3 (fT3), free T4, and thyroid-stimulating hormone (TSH) levels in 338 RA patients. After excluding patients taking anti-thyroid drugs or having anti-thyroid antibodies, we compared the clinical characteristics of the RA patients with low fT3 to those with normal/high fT3, before and after RA treatment.Results: Six percent of RA patients had low fT3 levels. Patients with low fT3 were older and had higher disease activity scores (DAS28), higher Steinbrocker stage, higher health assessment questionnaire scores, lower body mass index, and lower hemoglobin and albumin levels compared with normal/high-fT3 patients. After RA treatment, fT3 levels normalized in half of the low-fT3 patients and remained low in the other half. Although DAS28 scores were similarly improved in both subgroups of the low-fT3 patients, anemia and hypoalbuminemia did not normalize in the persistently low-fT3 subgroup.Conclusion: Low serum fT3 levels represent the profound wasting seen in RA patients that is characterized by anemia and hypoalbuminemia and that cannot be evaluated by DAS28 scores alone.

Multicenter Prospective Study of the Efficacy and Safety of Combined Immunosuppressive Therapy With High-Dose Glucocorticoid, Tacrolimus, and Cyclophosphamide in Interstitial Lung Diseases Accompanied by Anti-Melanoma Differentiation-Associated Gene 5-Positive Dermatomyositis.

OBJECTIVE: Interstitial lung disease (ILD) accompanied by anti-melanoma differentiation-associated gene 5 (anti-MDA-5)-positive dermatomyositis (DM) is often rapidly progressive and associated with poor prognosis. Because there is no established treatment, we undertook this study to prospectively evaluate the efficacy and safety of a combined immunosuppressive regimen for anti-MDA-5-positive DM patients with ILD. METHODS: Adult Japanese patients with new-onset anti-MDA-5-positive DM with ILD (n = 29) were enrolled at multiple study centers from 2014 to 2017. They were treated with a regimen of high-dose glucocorticoids (GCs), tacrolimus, and intravenous cyclophosphamide (IV CYC). Plasmapheresis was used if a patient's condition worsened after the regimen started. The primary end point was 6-month survival, which was compared between this group of patients and a historical control group (n = 15) consisting of anti-MDA-5-positive DM patients with ILD who received step-up treatment (high-dose GC and stepwise addition of immunosuppressant). Secondary end points were 12-month survival rate, adverse events, and changes in laboratory data. RESULTS: The combined immunosuppressive regimen group showed significantly higher 6-month survival rates than the step-up treatment group (89% versus 33%; P < 0.0001). Over a period of 52 weeks, improvements in anti-MDA-5 titers, serum ferritin levels, vital capacity, and chest high-resolution computed tomography scores were observed. The combined immunosuppressive regimen group received IV CYC nearly 20 days earlier with shorter intervals and tended to receive plasmapheresis more often than patients undergoing step-up treatment. Cytomegalovirus reactivation was frequently observed over 52 weeks. CONCLUSION: A combined immunosuppressive regimen is effective for anti-MDA-5-positive DM patients with ILD. Plasmapheresis can be used for additional effect in intractable disease. Patients should be carefully monitored for opportunistic infections during treatment.

Visceral disseminated varicella zoster virus infection after rituximab treatment for granulomatosis with polyangiitis.

We report on a 30-year-old Japanese woman with granulomatosis with polyangiitis (GPA) complicated by pituitary diabetes insipidus and multiple lung granulomas. The granulomas disappeared with prednisolone (50 mg/day) and rituximab, although continuous nasal desmopressin was needed to control diabetes insipidus after immunosuppressive therapies. At the time of presentation, the patient had abdominal pain and disseminated intravascular coagulation but no rash. She died of continuous hemorrhage from her skin of neck, mucosa of her pharynx, and small intestine. At autopsy, varicella zoster virus (VZV)-DNA detected in serum and VZV antigens detected in tissues of her pharynx, esophagus, and liver led to a diagnosis of visceral disseminated VZV infection (VD-VZV). She also complicated cytomegalovirus infection in her stomach and ovaries. Her posterior pituitary gland had been replaced by foamy macrophages. In 38 reported cases of VD-VZV, rash appeared following the onset of abdominal pain (mean interval, 6.5 days) but was lacking in 11% of cases. The mortality rate associated with VD-VZV was as high as 29% and survived cases were treated with antivirals earlier than mortal cases. A quick diagnosis with detection of VZV-DNA or VZV antigens in sera or tissues using PCR or immunohistochemistry examination and early empirical treatment with antivirals are important.

Successful treatment by rituximab in a patient with TAFRO syndrome with cardiomyopathy.

  TAFRO syndrome is a newly defined disease entity which is characterized by thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and organomegaly. A histological pattern of multiple lymphadenopathy of atypical Castleman's disease (CD) is also an important characteristic. A 48-year-old man was referred to our hospital with fever, asthenia, bilateral pleural effusion, ascites, generalized edema, dyspnea, hypoalbuminemia, severe thrombocytopenia, anemia, renal failure and proteinuria, whereas bacterial culture and serological and PCR tests for various viruses were all negative. A CT scan showed multiple lymphadenopathy and tissue sampling of inguinal lymph nodes showed a compatible histology with plasma cell type CD. A diagnosis of TAFRO syndrome was made. Ten days after hospitalization, sudden cardiac insufficiency and anuria developed. Despite glucocorticoid pulse therapy, tocilizumab and plasmapheresis, clinical and laboratory features did not improve. On the 34(th) hospital day, we started rituximab. His general condition started to improve in several days, and by one month later anasarca had improved drastically. Thrombocytopenia and renal function gradually improved and finally normalized. Cardiac motion also improved. This is the first report of a TAFRO syndrome patient with cardiomyopathy, who was successfully treated with rituximab.

[Efficacy of disease modifying anti-rheumatic drugs on bone destruction in rheumatoid arthritis].

There had been proved the efficacy of preventing bone destruction by using disease modifying anti-rheumatic drugs (DMARDS) such as methotrexate(MTX). A certain combination of DMARDS is more effective than treated alone. But the data about DMARDS combination therapy or DMARDS used mainly in Japan is not abundant, and there needed to establish the evidences of them.

Cloning of a cDNA encoding the Gly m Bd 28K precursor and its vacuole transport in tobacco BY2 suspension-cultured cells.

Gly m Bd 28K (Gm28K), a soybean allergen, is formed as a preproprotein consisting of a predicted signal peptide, Gm28K, and the 23-kDa peptide (Gm23K). Gm28K and Gm23K are found in the protein-storage vacuoles (PSVs) of developing soybean seeds. However, the complete structure of Gm28K has not yet been identified and its processing and transport to the vacuoles has never been clarified. In the present study, we elucidated the 5'-nucleotide sequence of cDNA encoding the Gm28K precursor and identified a putative signal peptide (SP) with 24 N-terminal amino acid residues. We expressed peptides from the Gm28K precursor as fusion proteins with enhanced green fluorescent protein (EGFP) in tobacco BY2 suspension-cultured cells. BY2 cells transformed by an expression vector for SP-EGFP-Gm28-Gm23K (SP-EGFP-Gm28-Gm23K/BY2 cells) and SP-Gm28-Gm23K-EGFP/BY2 cells produced the EGFP fused-Gm28K precursor, and the EGFP-fluorescence in their vacuoles were recorded. In the experiments with SP-EGFP/BY2 and SP-EGFP-Gm28K/BY2 cells, large amounts of the EGFP segments were secreted into the medium. On the other hand, the fluorescence of EGFP in SP-EGFP-Gm23K/BY2 cells was shown to accumulate only in the endoplasmic reticulum without secretion into the medium. These findings show that the SP signals the precursor to enter the lumen of the endoplasmic reticulum and that both the Gm28K and Gm23K components may be involved in the transport from the endoplasmic reticulum (ER) lumen via the Golgi to the vacuoles in a proprotein form.

Sweet's syndrome associated with systemic lupus erythematosus: a case report and review of the literature.

A 35-year-old Japanese female patient with systemic lupus erythematosus (SLE) presented with fever, erythematous papules and nodules, and polyarthralgia. Skin biopsy of a nodule was compatible with Sweet's syndrome. The papules/nodules were well treated with an oral glucocorticoid. Thirty cases of Sweet's syndrome associated with lupus erythematosus (LE) have been reported in the published work. The mean age was 34.2 years. They showed a higher male ratio (male : female, 1:2) compared with patients with SLE (1:9) and Sweet's syndrome (1:3.7). Sweet's syndrome may occur as a manifestation of LE, and a moderate dose of an oral glucocorticoid will result in a good response.

Analysis and functionality of major polyphenolic components of Polygonum cuspidatum (itadori).

Polygonum cuspidatum has been broadly utilized as a herbal medicine in Asia, but the outline of the polyphenol compounds in the plant has not been characterized well. In the present study, the major polyphenolic components were isolated from the roots of P. cuspidatum, and identified as resveratrol and its glucosides, resveratroloside and polydatin. On the other hand, chlorogenic acid was found to be one of the polyphenolic components in the leaves and stems of the plant. Next, we elucidated that resveratrol derivatives and chlorogenic acid exhibit α-glucosidase inhibitory activities, and resveratroloside exhibits the same inhibitory activity as quercetin does. Furthermore, DPPH radical scavenging activities of antioxidants including resveratrol derivatives and chlorogenic acid derivatives were examined by initial rate analyses of their reactions. Subsequently, it was revealed that resveratrol derivatives have slow-acting effects on the radical scavenging activity and that chlorogenic acid derivatives exhibit very fast-acting effects.

Tumor-suppressive lipoxygenases inhibit the expression of c-myc mRNA coding region determinant-binding protein/insulin-like growth factor II mRNA-binding protein 1 in human prostate carcinoma PC-3 cells.

8S-Lipoxygenase (8S-LOX) is known as a mouse homolog of human 15S-LOX-2. 15S-LOX-2 was down-regulated in malignant transformation of prostate epithelial cells, and its overexpression caused cell cycle arrest. To determine whether 8S-LOX would have a growth inhibitory effect on prostate carcinoma, we obtained human prostate carcinoma PC-3 cells expressing 8S-LOX or 15S-LOX-2. The growth rate of cells measured by colorimetric assay was reduced by expression of 8S-LOX and 15S-LOX-2. The addition to enzyme-expressing cells of arachidonic acid enhanced the growth suppressive effect, whereas the expression of catalytically inactive mutants did not affect cell growth, suggesting that the effect was product-dependent. DNA microarray and quantitative reverse transcription-PCR analyses revealed that the c-myc mRNA coding region determinant-binding protein/insulin-like growth factor II mRNA-binding protein 1 (CRD-BP/IMP-1), known as an oncofetal protein, was down-regulated in 8S-LOX- and 15S-LOX-2-expressing PC-3 cells. Targeted knockdown of CRD-BP/IMP-1 resulted in inhibition of the DNA synthesis rate of PC-3 cells as measured by bromodeoxyuridine incorporation. We propose that expression of 8S-LOX and 15S-LOX-2 suppresses CRD-BP/IMP-1 expression, resulting in inhibition of human prostate carcinoma PC-3 cell proliferation.

Antiproliferative activity of guava leaf extract via inhibition of prostaglandin endoperoxide H synthase isoforms.

Prostaglandin endoperoxide H synthase (PGHS) is a key enzyme for the synthesis of prostaglandins (PGs) which play important roles in inflammation and carcinogenesis. Because the extract from Psidium guajava is known to have a variety of beneficial effects on our body including the anti-inflammatory, antioxidative and antiproliferative activities, we investigated whether the extract inhibited the catalytic activity of the two PGHS isoforms using linoleic acid as an alternative substrate. The guava leaf extract inhibited the cyclooxygenase reaction of recombinant human PGHS-1 and PGHS-2 as assessed by conversion of linoleic acid to 9- and 13-hydroxyoctadecadienoic acids (HODEs). The guava leaf extract also inhibited the PG hydroperoxidase activity of PGHS-1, which was not affected by nonsteroidal anti-inflammatory drugs (NSAIDs). Quercetin which was one of the major components not only inhibited the cyclooxygenase activity of both isoforms but also partially inhibited the PG hydroperoxidase activity. Overexpression of human PGHS-1 and PGHS-2 in the human colon carcinoma cells increased the DNA synthesis rate as compared with mock-transfected cells which did not express any isoforms. The guava leaf extract not only inhibited the PGE(2) synthesis but also suppressed the DNA synthesis rate in the PGHS-1- and PGHS-2-expressing cells to the same level as mock-transfected cells. These results demonstrate the antiproliferative activity of the guava leaf extract which is at least in part caused by inhibition of the catalytic activity of PGHS isoforms.