Yasuji Yoshikawa

Chronic inhibition of Rho kinase blunts the process of left ventricular hypertrophy leading to cardiac contractile dysfunction in hypertension-induced heart failure

The Gq-RhoA-Rho kinase pathway, activated by neurohormonal factors such as angiotensin II (Ang II), has been proposed to be one of the important signaling pathways involved in the progression of left ventricular (LV) hypertrophy to heart failure. We tested the hypothesis that chronic inhibition of Rho kinase prevents this process. Heart failure was induced in Dahl salt-sensitive (DS) rats fed an 8% NaCl diet from 8 until 17 weeks of age. Y-27632 (5 mg/kg per day), a selective Rho kinase inhibitor, was applied orally to DS rats starting at 10 weeks of age for 7 weeks (DS/Y+). DS rats without Y-27632 (DS/Y-) and Dahl salt-resistant (DR) rats fed the 8% NaCl diet were regarded as non-therapeutic and normotensive controls, respectively. At 17 weeks of age, there was no significant difference in the blood pressure of DS/Y- and DS/Y+ rats. DS/Y- rats exhibited: (1) increases in LV mass, cross-sectional area (CSA) of cardiomyocytes, and interstitial fibrosis; (2) contractile dysfunction, i.e. decreases in LV ejection fraction and % fractional shortening, and prolongation of time to peak tension as well as to 50% relaxation in the twitch contraction of isolated papillary muscle; and (3) increases in the protein expression of Galphaq and Rho kinase in the myocardial membrane fraction. In DS/Y+ rats, the degree of myocardial hypertrophy was significantly inhibited in association with improved contractile function, without a decrease in the degree of interstitial fibrosis. Our results suggest the possibility that the Gq-Rho kinase pathway plays an important role in the process of hypertension-induced LV hypertrophy leading to contractile dysfunction.

Reduced tau expression in gastric cancer can identify candidates for successful Paclitaxel treatment

A recent study disclosed that breast cancer cases with low ‘tau’ expression can predict susceptibility to Paclitaxel administration. In the current study, the clinical significance of tau expression in gastric cancer cases was established by identifying candidates with Paclitaxel administration. Tissue specimens from 20 cases of in-operable or noncuratively resected gastric cancer were examined. Subsequent to the administration of 80 mg m−2 of Paclitaxel in six 3-h intravenous infusions, the clinical effectiveness of Paclitaxel was evaluated by the size of metastatic lesions with computed tomography. The status of the tau expression was determined by immunohistochemistry. Based on a previously reported classification scheme, six were classified as tau-negative expression (0, 1+) cases and 14 were classified as tau-positive expression (2+, 3+) cases. All six (100%) cases of tau-negative expression showed a favourable response (partial response or minor response) to Paclitaxel administration. However, 12 (86%) of the 14 cases of tau-positive expression showed progressive disease (n=11) or no change (n=1) after Paclitaxel administration. The serum carcinoembryonic antigen values of the six cases of tau-negative expression were markedly decreased in comparison to the 14 tau-positive cases. These data indicate that tau-negative expression can be used to select gastric cancer patients, which will favourably respond to Paclitaxel treatment.

Suppressed tumorigenicity of human endometrial cancer cells by the restored expression of the DCC gene

To obtain functional evidence for DCC as a tumour suppressor associated with endometrial cancer, the human DCC cDNA encoding a complete open reading frame (ORF) was transfected into highly tumorigenic human endometrial carcinoma cells, HHUA and Ishikawa in which DCC expression was completely deleted. Reconstituted expression of DCC in HHUA had little effect on in vitro growth, but suppressed tumour formation in mice completely. The clones from Ishikawa had abundant DCC expression similar to that in normal endometrium. Their growth in vitro was suppressed and showed apoptotic phenotype. Lower levels of DCC expression in the prolonged passaged clones did not induce apoptosis, but still had the potential to suppress tumorigenicity. These observations imply a role of DCC in regulation of normal endometrial cell growth, and categorize DCC as the tumour suppressor gene for endometrial cancer.

A novel therapeutic trial of homogentisic aciduria in a murine model of alkaptonuria

AbstractAlkaptonuria is a rare autosomal recessive disorder characterized by homogentisic aciduria, ochronosis, and arthritis. Although a deficiency of homogentisic acid 1,2-dioxygenase has recently been confirmed at the molecular level, no effective treatment regimen has yet been developed for this disorder. In the present study, 2(-2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), a potent inhibitor of p-hydroxyphenylpyruvate dioxygenase (which catalyzes the formation of homogentisic acid from p-hydroxyphenylpyruvic acid) was adopted as a possible therapeutic agent for alkaptonuria. NTBC dose-dependently reduced the urinary output of homogentisic acid in a murine model of alkaptonuria that had been created with ethylnitrosourea. These findings suggest that NTBC may be the first potent pharmacotherapeutic agent for alkaptonuria.

Xanthogranulomatous cholecystitis: importance of chemical-shift gradient-echo MR imaging

Accepted: 27 September 2002 Published online: 13 February 2003

A novel mechanism in suppression of erythropoiesis during inflammation: A crucial role of RCAS1

Abstract:  A novel human tumor‐associated antigen, receptor‐binding cancer antigen expressed on SiSo cells (RCAS1), induces apoptosis in normal human erythroid progenitor cells, which express putative RCAS1 receptors. In the present study, we investigated a possible role of RCAS1 produced by human peripheral blood monocytes (CD14‐positive cells) and monocyte‐derived macrophages. RCAS1 was immunohistochemically detected in monocytes as well as macrophages. When macrophages were stimulated with lipopolysaccharide (LPS), the expression of RCAS1 was remarkably enhanced. An increased production of RCAS1 mRNA was observed in LPS‐stimulated macrophages by quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) analysis. Soluble RCAS1 molecules were only detected in the culture supernatants obtained from LPS‐stimulated macrophages. Moreover, LPS‐stimulated macrophages induced cell death of erythroid progenitor cells through RCAS1 production. These results suggest that macrophages may negatively regulate erythropoiesis at least in part through the production of RCAS1 molecules, and this may contribute to the pathogenesis of the anemia seen in patients with inflammatory disorders.

Clinicopathologic and prognostic values of apolipoprotein D alterations in hepatocellular carcinoma

We previously identified apolipoprotein D (Apo D) as a novel tumor suppressor gene based on the pharmacological unmasking of epigenetic silencing. We analyzed Apo D expression using real‐time reverse transcription‐PCR and evaluated its expression status based on the clinicopathological parameters of 70 patients with hepatocellular carcinoma (HCC). Immunohistochemical staining was also performed. We determined the methylation status of Apo D gene promoter by methylation‐specific PCR (MSP). The Apo D gene‐expression in tumor tissue was significantly lower than that in nontumor tissue (p = 0.011). A low Apo D expression significantly correlated with less‐differentiated HCC (p = 0.019). Immunohistochemical studies confirmed a decreased Apo D expression in poorly differentiated tumors. The prognosis of patients with a lower Apo D gene‐expression was significantly worse than that in those with a higher expression (p = 0.028). The Apo D gene‐expression was an independent prognostic factor (relative risk: 2.36, p = 0.018). An MSP assay showed a low‐level of methylation in well differentiated HCC and a high‐level of methylation in less differentiated tumors. Apo D may be a novel tumor suppressor gene of HCC, and its expression status may be a useful biomarker for predicting the patient outcome.

Human monoclonal rheumatoid factors augment arthritis in mice by the activation of T cells

In order to investigate the in vivo role of rheumatoid factor (RF), the effects of the administration of human monoclonal (m) IgM‐RF and IgG‐RF on the development of arthritis in mice were examined. The administration of human mRFs into mice immunized with type II collagen (CII) markedly enhanced the clinical score and paw swelling. The severity of arthritic joint disease with a marked infiltration of lymphoid cells, proliferation of synovial membrane, pannus formation and destruction of articular cartilage was significantly enhanced in both groups receiving RF (RF‐enhanced arthritis). Skin ulcers were also observed in some of these RF‐enhanced arthritis mice, whereas no such signs were observed in CII‐immunized mice without mRFs. Both IgM‐RF and IgG‐RF increased CII‐specific IgG antibodies in circulation, and the severity of arthritis correlated with the production of high titres of anti‐CII antibodies. In vivo treatment of RF‐enhanced arthritis mice with an anti‐CD4 MoAb or an anti‐CD8 MoAb inhibited the induction and progression of arthritis in these mice. Administration of RF to severe combined immunodeficient (SCID) mice with arthritis developed by the transfer of spleen cells from CII‐immunized mice, prolonged the arthritis and enhanced the severity. This murine model of RF‐enhanced arthritis may provide a useful tool for analysing the pathogenesis of rheumatoid arthritis in RF‐positive patients.

Extranodal Multiple Involvement of Enteropathy-Type T-Cell Lymphoma without Expression of CC Chemokine Receptor 7

Enteropathy-type T-cell lymphoma (ETCL) is a rare extranodal lymphoma that tends to disseminate into the intestines and other extranodal organs. We present a case of ETCLdf with involvement of the lungs and kidneys and report CC chemokine receptor 7 (CCR7) expression of lymphoma cells. A 73-year-old man was admitted to the hospital with a complaint of abdominal pain. Multiple ulcers and perforations were observed in the small intestine, and partial resection of the ileum was performed. Histological examination of the resected specimen revealed diffuse proliferation of atypical large lymphoid cells. The diagnosis was ETCL with dissemination into the lungs and kidney. Lymphoma cells of the small intestine and in pleural effusion were CD3+, CD4+, CD7+, CD8-, CD25-, CD56-, CD103+/-, and TIA-1+. Rearrangement of the T-cell receptor β gene was detected, and human T-lymphotropic virus was not integrated. Combination chemotherapy did not result in a sustained response. The results for CCR7 expression of lymphoma cells in the lung and pleural effusion were negative. Therefore we concluded that lymphoma cells did not migrate into the lymph nodes but instead spread into the extranodal organs.

Relevance of ER to the Development of Endometrial Hyperplasia and Adenocarcinoma.

Estrogen has an important role in both the etiology and treatment of hormone-dependent endometrial cancers, although the mechanism remains elusive. To define the role of estrogen-mediated signaling we investigated the biological significance of estrogen receptors (ER) in NIH3T3 cell transformation via the [12Val] K-Ras mutant. This mutant enhanced the steady state level and transcriptional activity of ER. In addition, overexpression of both wild type K-Ras and ER transformed NIH3T3 cells. Co-expression of the progesterone receptor (PR) with mutant K-Ras led to suppression of tumorigenicity and inhibition of ER activation. The antisense oligomers complementary to ER suppressed proliferation and transformed phenotypes of K12V cells. These observations support the importance of ER in Ras-mediated cell transformation.To address whether ER activation is also important in the development of human endometrial cancers, we investigated ER and PR expression levels in premalignant and malignant endometrial lesions. The results suggested the implication of ER abundance in endometrial hyperplasias, though modulation of PR expression by ER was retained. Gl adenocarcinoma also expressed higher levels of ER while PR modulation by ER was abrogated. These data implied the importance of ER activities in endometrial hyperplasia and Gl adenocarcinoma development.