Biomedical subjects

Kazuhiro Suzuki

Publications and source records attributed to Kazuhiro Suzuki.

104 records · Page 6Linked to original sources

PubMed2001

LIM kinase 1 modulates opsonized zymosan-triggered activation of macrophage-like U937 cells. Possible involvement of phosphorylation of cofilin and reorganization of actin cytoskeleton.

We have previously reported that cofilin, an actin-binding protein, plays an important role in phagocyte functions, such as respiratory burst, phagocytosis, and chemotaxis. On the other hand, it was recently found that LIM motif-containing kinase (LIMK) phosphorylates cofilin. In this work, we investigated the roles of LIMK in activated phagocytes. The results of immunostaining showed that in dormant phagocytes the endogenous LIMK1 was diffusely distributed in the cytosol of macrophage-like U937 cells, and when activated by opsonized zymosan (OZ), it was translocated to plasma membranes. Green fluorescence protein (GFP)-conjugated LIMK was expressed in the phagocytes, and the GFP-positive cells were isolated by a fluorescence-activated cell sorter. The isolated wild-type LIMK-overexpressing cells produced superoxide at a rate that was 3.2-fold higher than that of only GFP-expressing control cells, whereas the respiratory burst of dominant negative LIMK1(D460A)-expressing cells decreased to 31% of that of the control cells. Phagocytic activity monitored by using Texas Red-labeled OZ was also decreased in the D460A-expressing cells. By immunoblotting using a specific anti-phosphorylated cofilin antibody, it was revealed that in the OZ-activated wild-type LIMK1-GFP-expressing cells, the phosphorylated cofilin increased by 2.3-fold, and that in the OZ-activated D460A-GFP-expressing cells, the phosphorylated cofilin decreased to 47% of that of only GFP-expressing cells (mock control). Furthermore, in the wild-type LIMK1-expressing cells, OZ-evoked increase in filamentous actin was markedly enhanced, whereas in the dominant negative LIMK1-expressing cells, the total level of F-actin was strongly suppressed. These results suggest that LIMK1 regulates the functions of phagocytes through phosphorylation of cofilin and enhances the formation of filamentous actin.

Actin Depolymerizing Factors↗

PubMedDate not supplied

Lyn, one of the Src-family tyrosine kinases expressed in phagocytes, plays an important role in beta2 integrin-signalling pathways in opsonized zymosan-activated macrophage-like U937 cells.

We have investigated the contribution of Hck, Lyn and Fgr, highly expressed Src family tyrosine kinases (SFKs) in signalling pathways in opsonized zymosan (OZ)-activated phagocytes by using short interfering RNAs (siRNAs). Treatment of macrophage-like U937 cells with the siRNAs targeted to these transcripts decreased the protein content of each kinase to less than half that of untreated cells. Among these siRNAs, siRNA targeted to Lyn was the most effective in diminishing two kinds of phagocyte functions, that is oxidative burst and phagocytosis. Phosphorylation of c-Cbl, a multidomain adaptor protein in the beta2 integrin-signalling pathway, was also largely inhibited by treatment with siRNA to Lyn. Thus, the results with siRNAs highly specific for Hck, Lyn and Fgr suggested that, among these three SFKs, Lyn plays the most important role in signalling pathways downstream of beta2 integrins in OZ-stimulated phagocytes.

CD18 Antigens↗

PubMedDate not supplied

A p53 codon 72 polymorphism associated with prostate cancer development and progression in Japanese.

An association between the Pro/Pro genotype of p53 codon 72 and a lower risk of prostate cancer in Caucasians was recently reported. However, the association of this polymorphism with prostate cancer risk in a Japanese population has not been clarified. We performed a case-control study consisting of 114 prostate cancer patients and 105 noncancer controls. Sixty-nine percent (79 of 114) of the patients had a positive family history. The genotypic frequencies in the controls were 39.0% for Arg/Arg, 54.3% for Arg/Pro and 6.7% for Pro/Pro; they were in Hardy-Weinberg equilibrium. When a comparison of the distribution of the p53 codon 72 polymorphism was made between patients with a first-degree family history and all control subjects, the adjusted odds ratios (ORs) for prostate cancer associated with the Arg/Arg, Arg/Pro and Pro/Pro genotypes were 1.00, 0.99 [95% confidence interval (CI) 0.53-1.88] and 2.80 (95% CI 1.04-7.53), respectively. When stratification of cases was performed based on clinical stage (localized or metastatic cancer) and pathological grade (a Gleason score of <7 or > or =7), there tended to be a greater number of patients with localized cancers among those patients with the Arg/Pro genotype than among those with the Arg/Arg genotype (overall cases: age-adjusted OR 0.36, 95% CI 0.13-1.00, p = 0.049; positive family history cases: age-adjusted OR 0.25, 95% CI 0.075-0.84, p = 0.025). In addition, there tended to be a greater number of patients with low-grade cancers among those with the Pro/Pro genotype than among those with other genotypes (overall cases: age-adjusted OR 0.41, 95% CI 0.13-1.30, p = 0.13; positive family history cases: age-adjusted OR 0.20, 95% CI 0.004-0.89, p = 0.035). The present findings suggest that the Pro/Pro genotype of p53 codon 72 played a role in prostate cancer susceptibility in a Japanese population. However, the Pro allele did not appear to worsen such clinical parameters as clinical stage or pathological grade.

Adult↗

PubMedDate not supplied

The role of integrins in the modulation of neurotransmitter release from motor nerve terminals by stretch and hypertonicity.

Integrins are found at most or all synapses and play a variety of roles. At frog neuromuscular junctions, mechanical tension on integrins due to muscle stretch or hypertonicity causes a powerful modulation of release efficacy. Understanding the mechanism(s) of integrin-mediated modulation will likely further our understanding of mechanisms of neurotransmitter release. The modulation of evoked release with stretch occurs with no detectable delay, does not adapt, and bypasses the Ca(2+) triggering step in vesicle fusion. It depends primarily on integrin bonds to native ligands and requires that one or more proteins in the link between integrins and vesicle fusion be dephosphorylated. Hypertonicity, studied in both frog and Drosophila terminals, causes a larger but slower phasic-tonic change in spontaneous release, which is also Ca(2+)-independent and mostly dependent on integrins, but not dependent on the phosphorylation state of molecules in its pathway of action. In Drosophila, the integrin-dependent component involves the cAMP/PKA pathway, and is absent in mutants lacking PKA. Both stretch and hypertonicity responses in frog terminals are enhanced by agents that elevate PKA levels, suggesting that, in frogs, the cAMP/PKA cascade primarily determines the size of the pool of vesicles available for release by the integrin-mediated mechanism and is not a direct intermediary in the modulation. Evoked release is affected little or even inhibited by hypertonicity. In Drosophila, the inhibition can be explained by a decrease in Ca(2+) influx. The effect of hypertonicity on evoked release in frogs may similarly be a balance between mechanisms that enhance spontaneous release and those that suppress I (Ca).

Animals↗

PubMedDate not supplied

Changes in testosterone and dihydrotestosterone levels in male rat accessory sex organs, serum, and seminal fluid after castration: establishment of a new highly sensitive simultaneous androgen measurement method.

It is known that abnormal androgen dynamics in the tissues is a cause of androgen-dependent disorders. Investigation of tissue androgen levels could provide a clue to the elucidation of disorders. However, it is difficult to measure a trace amount of androgen in the tissues. We established a highly sensitive simultaneous quantification method of testosterone and dihydrotestosterone (DHT), which play the most important roles in the body among androgenic steroids in trace amounts, and investigated time course changes in testosterone and DHT levels in male accessory sex organs, serum, and seminal fluid after castration in rat models. In addition, changes in the testosterone/DHT ratio of male accessory sex organs and seminal fluid were observed. The simultaneous testosterone and DHT measurement method established by us was validated. Intra-assay variation and interassay precision and accuracy were all within +/-20%, and the quantification limits of testosterone and DHT were both 15.6 pg/g. With the use of this method, the testosterone and DHT levels in the prostate, seminal vesicles, and serum immediately after castration were similar to those previously reported. The testosterone and DHT levels were 350 pg/g and 605 pg/g, respectively; which showed dominance of DHT in seminal fluid, although it was not as marked as that in the male accessory sex organs. Androgens decreased with time after castration in the accessory sex organs, serum, and seminal fluid. In the prostate and seminal vesicles, testosterone and DHT decreased to about 50% and about 2% of the normal levels, respectively, 72 hours after castration. The serum levels were under the quantification limits 6 hours after castration and thereafter. In seminal fluid, the testosterone and DHT levels decreased to 49% and 35% of normal levels, respectively, 72 hours after castration. The testosterone/DHT ratio in the male accessory sex organs was lower in the prostate (0.06) than in the seminal vesicles (0.13) immediately after castration. In the seminal fluid, changes in the ratio were small compared with those in the accessory sex organs and serum. These results showed that our method was capable of measuring testosterone and DHT in very small amounts of samples such as prostate biopsy specimens, and it might provide a clue to the elucidation of the pathology of androgen-dependent disorders.

Animals↗

PubMedDate not supplied

MR spectroscopy as a reliable diagnostic tool for localization of prostate cancer.

BACKGROUND: Magnetic resonance spectroscopy (MRS) is a new diagnostic tool which allows the detection of cellular metabolites. We assessed the usefulness of single- voxel MRS diagnosis for localization of prostate cancer. PATIENTS AND METHODS: The study population consisted of 10 patients with prostate cancer. We set I or 2 voxels at the peripheral zone (PZ) of the prostate where biopsy had confirmed adenocarcinoma. MRS provided metabolic information about citrate, creatine and choline levels. We calculated the ratio of these metabolites ([choline + creatine]/citrate) and judged areas where the metabolic ratio was greater than 0.86 as positive. RESULTS: Thirteen out of 19 voxels showed a cancer pattern which indicated a high choline peak and low citrate peak The accuracy, sensitivity and specificity of MRS diagnosis of tumor localization were 84.2%, 81.3% and 100%, respectively. CONCLUSION: MRS is useful for the diagnosis of prostate cancer localization.

Adenocarcinoma↗

PubMedDate not supplied

Association of HPC2/ELAC2 polymorphism with prostate cancer risk in a Japanese population.

BACKGROUND: To investigate the relationship between two common variants (Ser217 and Ala541) of the HPC2/ELAC2 gene and prostate cancer risk in a Japanese population, we performed a case-control study. MATERIALS AND METHODS: Cases and controls consisted of 81 prostate cancer patients with a family history and 106 controls. Ser217 and Ala541 polymorphisms were analyzed by the restriction fragment length polymorphism method. RESULTS: In controls, 94.5% and 100.0% had wild-type Ser217Ser and Ala541Ala genotypes, respectively. 5.7% of the controls had the Leu217 genotype. No Thr541 genotype was observed in the controls. 92.6% and 97.5% of the cases had the Ser217Ser and Ala541Ala genotypes. No significant differences were observed in the genotypic frequencies between controls and cases. We stratified prostate cancer cases according to the pathological grade (low- or high-grade) or the clinical stage (localized or metastatic). There was no statistical difference between the genotypic frequencies between the groups. CONCLUSION: The present study suggested that the common variants in the HPC2/ELAC2 gene play a limited role in the risk of prostate cancer in the Japanese population.

Adult↗

PubMedDate not supplied

Gene expression profiles of human BPH (II): Optimization of laser-capture microdissection and utilization of cDNA microarray.

Laser capture microdissection (LCM) enables the dissection of heterogeneous components of tissues, helping to investigate the molecular properties of these tissues. We have reported gene expression profiles in human benign prostatic hyperplasia (BPH) using LCM and quantitative real-time PCR. In the current work, we extended the previous observations. Firstly, we studied the relationship between the number of dissected acini and amplification by PCR, and found that androgen receptor (AR) and 18S rRNA transcripts were successfully amplified from total RNA obtained from one prostate acinus. Furthermore, LCM-dissected samples were applicable to methylation-specific PCR of E-cadherin promoter gene after bisulfite modification of genomic DNA. Next, we performed cDNA microarray analysis to screen gene expression profiles in the epithelium and stroma. RNA was amplified by T7-RNA polymerase and labeled with Cy3 and Cy5. Epithelium-related or stroma-related genes were identified through cDNA microarray. We confirmed true gene expression levels by quantitative real-time PCR. In epithelium, E-cadherin and serine protease 2, Kunitz-type gene expression levels were significantly elevated, while the connective tissue growth factor gene expression level was significantly elevated in stroma. Thus, LCM-dissected samples were applicable to various molecular examinations including methylation-specific PCR and cDNA microarray, and this will contribute to a precise understanding of the molecular profiles of prostate glands.

DNA↗

PubMedDate not supplied

Association of genetic polymorphisms of glutathione-S-transferase genes (GSTM1, GSTT1 and GSTP1) with familial prostate cancer risk in a Japanese population.

BACKGROUND: Glutathione-S-transferases (GSTs) are active in the detoxification of a wide variety of toxins and carcinogens. The genetic polymorphisms of GSTM1, GSTT1 and GSTP1 genes have been studied to estimate the relative risk of various cancers. In the current study, we examined the association of the GST gene polymorphisms with familial prostate cancer in a Japanese population by performing a case-control study consisting of 81 familial prostate cancer cases and 105 normal controls. MATERIALS AND METHODS: No significant association of the GSTM1 and GSTT1 gene polymorphisms with familial prostate cancer risk was found; however, the Val/Val genotype of the GSTP1 gene significantly increased risk (OR = 9.31, 95% CI = 0.47-184, p = 0.030). The combination analysis of genotypes of the three genes showed that presence of two high-risk genotypes, i.e., null genotype of the GSTM1 or GSTT1 gene, or any Val genotypes of the GSP1 gene, significantly increased the risk of prostate cancer (OR = 2.67, 95% CI = 1.08-6.59, p = 0.03). Stratification of cases according to the pathological grade or the clinical stage showed no significant differences among categories. CONCLUSION: In the present study, we found that genotypes of GSTs, especially the Val-allele of the GSTP1 gene and the combination of three genotypes, were associated with familial prostate cancer risk.

Aged↗

PubMedDate not supplied

The combination of multi-voxel MR spectroscopy with MR imaging improve the diagnostic accuracy for localization of prostate cancer.

BACKGROUND: We assessed the usefulness of combined multi-voxel magnetic resonance spectroscopy (MRS) and MR imaging (MRI) in the diagnosis of prostate cancer localization. PATIENTS AND METHODS: MRS and MRI were performed in 21 patients with prostate cancer. On T2-weighted images, tumor localization was based on low signal intensity in the peripheral zone. At MRS, cancer patterns were diagnosed when the ratio of choline plus creatine to citrate was greater than 0.86. The results were analyzed with reference to pathological confirmation of prostate cancer at bilateral or unilateral lobe. RESULTS: Six out of 11 patients with unilateral positive biopsy specimens were diagnosed as unilateral cancer, and 9 of 10 patients with bilateral positive biopsy specimens were diagnosed as bilateral cancer on MRI. Two of 4 patients with unilateral cancer, who were not detected on MRI alone, were diagnosed as unilateral cancer on combined MRI and MRS. The accuracy of MRI alone was 71.4%, while that of combined MRI and MRS was 81.0%. CONCLUSION: Combined MRI and MRS improved the diagnostic accuracy for localization of prostate cancer.

Adenocarcinoma↗

PubMedDate not supplied

Placental growth factor gene expression in human prostate cancer and benign prostate hyperplasia.

BACKGROUND: Angiogenesis plays a crucial role in normal development and carcinogenesis of prostate glands. Placental growth factor (PlGF) belongs to the same family as the vascular endothelial growth factor. The presence of PlGF in human prostate has not been studied. In the current study, we investigated the gene expression profiles of PlGF in human prostate. MATERIALS AND METHODS: Gene expression of PlGF-1 and PlGF-2 was assessed by RT-PCR and direct sequencing. Gene expression levels were quantified by real-time PCR, and we compared the transcript levels among benign prostate hyperplasia (BPH), prostate caner (CAP) and CAP after androgen deprivation therapy (CAP-Tx). RESULTS: Human prostate cancer cells, LNCaP, PC-3 and DU-145, expressed both PlGF-1 and -2 mRNAs. Human prostate tissues, BPH, CAP and CAP-Tx, also expressed both types of PlGF mRNA. BPH and CAP-Tx expressed similar levels of PlGF, however, CAP expressed significantly lower levels of PlGF than BPH or CAP-Tx (p < 0.01). CONCLUSION: PlGF mRNA was expressed in human prostate. Significantly lower levels of PlGF in CAP in comparison with those in BPH or CAP-Tx suggested that PlGF might have effects on vasculogenesis and angiogenesis in prostate disease.

Alternative Splicing↗

PubMedDate not supplied

Association of the genetic polymorphism of the CYP19 intron 4[TTTA]n repeat with familial prostate cancer risk in a Japanese population.

BACKGROUND: Estrogen is crucial for development of benign prostate hyperplasia and prostate cancer. Aromatase (CYP19) is a key enzyme for estrogen synthesis in males. The genetic polymorphism of the CYP19 intron 4 [TTTA]n tetranucleotide has been studied in relation to breast cancer susceptibility. MATERIALS AND METHODS: We examined the association of the tetranucleotide repeat polymorphism of the CYP19 gene with familial prostate cancer risk in a Japanese population by performing a case-control study consisting of 99 familial prostate cancer cases and 116 normal controls. RESULTS: [TTTA] repeats ranged from 7 to 13 and were designated as A1 to A7 according to the repeat number. We did not observe any A3 allele among cases and controls, nor A7 among cases. Short repeat alleles, A1 and A2, had a tendency to be frequently observed in cases (odds ratio [OR] = 1.43, 95% confidence interval [CI] = 0.96-2.14, p = 0.080). Analysis of polymorphic genotypes showed that short genotypes, i.e., A1A1, A1A2 and A2A2, significantly increased prostate cancer risk in comparison with other longer genotypes (OR = 1.80, 95% CI = 1.04-3.11, p = 0.035). Stratification of cases according to the pathological grade or the clinical stage showed no significant differences among categories. CONCLUSIONS: In the present study, we found that short polymorphic genotypes of [TTTA]n repeats of the CYP19 gene were associated with familial prostate cancer risk.

Aged↗

PubMedDate not supplied

Cyclin D1 gene polymorphism and familial prostate cancer: the AA genotype of A870G polymorphism is associated with prostate cancer risk in men aged 70 years or older and metastatic stage.

BACKGROUND: Cyclin D1 is a key protein involved in cell cycle regulation. A common A870G single nucleotide polymorphism in exon 4 of the cyclin D1 gene (CCND1) has an effect on the transcription of two different cyclin D1 mRNAs. Association of the genetic polymorphism of A870G of CCND1 with several cancer risks has been reported. MATERIALS AND METHODS: We performed a case-control study consisting of 99 familial prostate cancer cases and 115 noncancer controls to examine the genotypic frequency of the CCND1 polymorphism. RESULTS: We did not observe a significant association of the genotypic frequency of CCND1 with overall cases and controls. However, the AA genotype of CCND1 showed a tendency to increase prostate cancer risk in subjects aged 70 years or older (odds ratio [OR] = 2.14, 95% confidence interval [CI] = 0.86-5.27, p = 0.096). Stratification of cases according to clinical stages showed that the AA genotype was significantly frequently observed in metastatic cancer in comparison with GG + AG genotypes (OR = 3.03, 95% CI = 1.11-8.23, p = 0.026). CONCLUSION: The present study suggested that the genetic polymorphism might be associated with familial prostate cancer risk in a Japanese population.

Aged↗

PubMedDate not supplied

Prognostic significance of plasma placental growth factor levels in renal cell cancer: an association with clinical characteristics and vascular endothelial growth factor levels.

BACKGROUND: Angiogenesis plays important roles in pathogenesis in human cancer. We assessed the relationship between clinical features of renal cell cancer (RCC) and PlGF levels in relation to VEGF. MATERIALS AND METHODS: Plasma PlGF and VEGF levels were measured in patients with renal cell cancer. The levels of these angiogenetic factors were analyzed in relation to clinical parameters. RESULTS: PlGF and VEGF levels in patients with RCC were significantly higher than those in non-cancer controls. PlGF levels were significantly associated with histological grade and total tumor vascularity (TTV), and VEGF levels were significantly associated with T, M stage, histological grade, venous invasion and TTV. Multivariate analysis showed plasma PlGF was an independent prognostic factor. CONCLUSION: These findings suggested that plasma PlGF levels were significantly associated with the clinical features of RCC, especially prognostic significance.

Carcinoma, Renal Cell↗