Biomedical subjects

T Shirakawa

Publications and source records attributed to T Shirakawa.

At least 19 recordsLinked to original sources

PubMed2006

Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction.

OBJECTIVES: Shinrin-yoku (walking and/or staying in forests in order to promote health) is a major form of relaxation in Japan; however, its effects have yet to be completely clarified. The aims of this study were: (1) to evaluate the psychological effects of shinrin-yoku in a large number of participants; and (2) to identify the factors related to these effects. METHODS: Four hundred and ninety-eight healthy volunteers took part in the study. Surveys were conducted twice in a forest on the same day (forest day) and twice on a control day. Outcome measures were evaluated using the Multiple Mood Scale-Short Form (hostility, depression, boredom, friendliness, wellbeing and liveliness) and the State-Trait Anxiety Inventory A-State Scale. Statistical analyses were conducted using analysis of variance and multiple regression analyses. RESULTS: Hostility (P<0.001) and depression (P<0.001) scores decreased significantly, and liveliness (P=0.001) scores increased significantly on the forest day compared with the control day. The main effect of environment was also observed with all outcomes except for hostility, and the forest environment was advantageous. Stress levels were shown to be related to the magnitude of the shinrin-yoku effect; the higher the stress level, the greater the effect. CONCLUSIONS: This study revealed that forest environments are advantageous with respect to acute emotions, especially among those experiencing chronic stress. Accordingly, shinrin-yoku may be employed as a stress reduction method, and forest environments can be viewed as therapeutic landscapes. Therefore, customary shinrin-yoku may help to decrease the risk of psychosocial stress-related diseases, and evaluation of the long-term effects of shinrin-yoku is warranted.

Adult↗

PubMed2006

Mitochondrial DNA determines androgen dependence in prostate cancer cell lines.

Prostate cancer progresses from an androgen-dependent to androgen-independent stage after androgen ablation therapy. Mitochondrial DNA plays a role in cell death and metastatic competence. Further, heteroplasmic large-deletion mitochondrial DNA is very common in prostate cancer. To investigate the role of mitochondrial DNA in androgen dependence of prostate cancers, we tested the changes of normal and deleted mitochondrial DNA in accordance with the progression of prostate cancer. We demonstrated that the androgen-independent cell line C4-2, established by inoculation of the androgen-dependent LNCaP cell line into castrated mice, has a greatly reduced amount of normal mitochondrial DNA and an accumulation of large-deletion DNA. Strikingly, the depletion of mitochondrial DNA from androgen-dependent LNCaP resulted in a loss of androgen dependence. Reconstitution of normal mitochondrial DNA to the mitochondrial DNA-depleted clone restored androgen dependence. These results indicate that mitochondrial DNA determines androgen dependence of prostate cancer cell lines. Further, mitochondrial DNA-deficient cells formed tumors in castrated athymic mice, whereas LNCaP did not. The accumulation of large deletion and depletion of mitochondrial DNA may thus play a role in the development of androgen independence, leading to progression of prostate cancers.

Androgens↗

PubMed2006

Association between ADAM33 polymorphisms and adult asthma in the Japanese population.

BACKGROUND: ADAM33, a member of the ADAM (a disintegrin and metalloprotease) family, is a putative asthma susceptibility gene recently identified by positional cloning. It is important to know whether the association exists in ethnically diverse populations. OBJECTIVE: To assess whether genetic functional variants of ADAM33 relate to the susceptibility or some phenotypes in adult patients with bronchial asthma in a Japanese population. METHODS: We searched for single nucleotide polymorphisms (SNPs) in ADAM33 by PCR-directed sequencing and identified 48 SNPs. Fourteen SNPs were selected with regard to the LD pattern, and genotyped by Taq-Man and PCR-RFLP methods. We conducted an association study of ADAM33 with 504 adult asthmatic patients and 651 controls, and haplotype analyses of related variants were performed. RESULTS: Significant associations with asthma were found for the SNPs T1 (Met764Thr), T2 (Pro774Ser), S2 and V-3 (with the lowest P-value for T1, P = 0.0015; OR 0.63). We analysed the haplotype using these four polymorphisms, and found a positive association with haplotype CCTG (P = 0.0024). CONCLUSION: Our results replicate associations reported recently in other ethnic populations, and suggest that the ADAM33 gene is involved in the development of asthma through genetic polymorphisms.

ADAM Proteins↗

PubMed2005

Rapid detection and differentiation of Gram-negative and Gram-positive pathogenic bacteria in urine using TaqMan probe.

Urinary tract infection has been shown to be quite complicated and often difficult to diagnose and treat. For appropriate diagnosis, it is very important to find the correct Gram stain classification as soon as possible, especially in severe cases where there is a possibility of severe sepsis developing. In order to solve this problem, we developed a new method to detect a Gram stain of bacteria obtained from 1 ml of urine from urinary tract infection patients using a consensus real-time PCR protocol with a TaqMan probe that allows detection of spiked bacterial 16S DNA from urine. We extracted DNA of 55 urine samples obtained from patients with complicated urinary tract infection and at the same time performed urine culture testing. After DNA extraction, they were subjected to real-time PCR using a TaqMan discrimination system. Sixteen kinds of bacteria were cultured from the urine culture testing. Of these bacteria, eight were classified as Gram-positive bacteria and the other eight were classified as Gram-negative bacteria. Of the 55 samples, the TaqMan technique result showed 27 samples that were classified as Gram-negative bacteria; 11 samples that were Gram-positive, 10 that included both Gram-negative and -positive bacteria, and 7 that showed no amplification. The classifications of all samples corresponded exactly to those determined by urine culture testing. The present genotyping method of real-time PCR using a TaqMan discrimination system could be applied to the rapid detection of Gram-positive or -negative bacteria in urine of urinary tract infection patients. This assay can differentiate those species tested, but whether the presence of other (untested) bacteria could lead to misinterpretation is unknown. For further investigation, it is important to test other (untested) bacteria in the near future.

Gram-Negative Bacteria↗

PubMed2004

An asthma-associated genetic variant of STAT6 predicts low burden of ascaris worm infestation.

Th-2 immune mechanisms are involved in the pathology of asthma and in the protective immune response to parasitic worms. Common upregulating genetic variants of Th-2 immune signalling are risk factors for asthma, and we tested whether they may confer a counteradvantage in protecting against parasitic worms. We examined the intensity of infection by the parasitic worm, Ascaris lumbricoides, by microsopic counting of ascaris eggs in the stool of 614 schoolchildren from an area of endemic ascaris infection in China. We investigated the relationship between the intensity of ascaris infection and common, asthma-associated genetic variants of Th-2 and Th-1 immune signalling. Ascaris egg counts per gram of stool (epg), mean 1068 epg, ranged from barely detectable (<240 epg) to heavy (approximately 9600 epg) in a skewed distribution. Logistic regression, after exploratory discriminant analysis, showed a major association between a common genetic variant of the 3'-UTR regulatory elements of the signal transducer and transactivating factor (STAT6) (P=0.0002) and egg counts, at the 77 th centile. Linear regression after log transformation of egg counts confirmed a highly significant association with this STAT6 variant (P=0.001). Thus, a common, asthma-associated, genetic variant of the pivotal transduction and transactivating factor for Th-2 immune signalling, STAT6, predicts increased resistance to ascaris worm infection. The evolution of enhanced resistance to parasitic worm infection, through human genetic variation in Th-2 immune signalling, may represent one origin for asthma.

3' Untranslated Regions↗

PubMed2004

Association of the hCLCA1 gene with childhood and adult asthma.

Asthma is caused by bronchial inflammation. This inflammation involves mucus overproduction and hypersecretion. Recently, a mouse model of asthma showed that gob-5 is involved in the pathogenesis of asthma. The gob-5 gene is involved in mucus secretion and its expression is upregulated upon antigen attack in sensitized mice. The observation suggests that human homologue of gob-5, hCLCA1 (human calcium-dependent chloride channel-1), may be involved in human disease. We screened for single-nucleotide polymorphisms (SNPs) in hCLCA1 in the Japanese population. We identified eight SNPs, and performed association studies using 384 child patients with asthma, 480 adult patients with asthma, and 672 controls. In haplotype analysis, we found a different haplotype distribution pattern between controls and childhood asthma (P<0.0001) and between controls and adult asthma (P=0.0031). We identified a high-risk haplotype (CATCAAGT haplotype; P=0.0014) and a low-risk haplotype (TGCCAAGT haplotype; P=0.00010) in cases of childhood asthma. In diplotype analysis, patients who had the CATCAAGT haplotype showed a higher risk for childhood asthma than those who did not (P=0.0011). Individuals who had the TGCCAAGT haplotype showed a lower risk for childhood asthma than those who did not (P<0.0001). Our data suggested that variation of the hCLCA1 gene affects patients' susceptibility for asthma.

Adolescent↗

PubMed2004

Polymorphisms in ADAM33 are associated with allergic rhinitis due to Japanese cedar pollen.

BACKGROUND: A recent report provided evidence that a disintegrin and metalloprotease domain 33 (ADAM33), a member of the ADAM family, is a novel susceptibility gene in asthma linked to bronchial hyper-responsiveness. However, there has been no investigation of the genetic role of ADAM33 variants in nasal allergy. OBJECTIVE: The purpose of this study was to test the association between ADAM33 polymorphisms and Japanese cedar pollinosis (JCPsis), a most common seasonal allergic rhinitis in Japan. METHODS: We conducted a case-control association study among a Japanese population, involving 95 adult individuals with JCPsis and 95 normal healthy controls. A total of 22 single-nucleotide polymorphisms (SNPs) in ADAM33 were genotyped using PCR-based molecular methods. RESULTS: Six SNPs of ADAM33 gene, three in introns (7575G/A, 9073G/A and 12540C/T) and three in the coding region (10918G/C, 12433T/C and 12462C/T), were strongly associated with JCPsis (P = 0.0002-0.022 for absolute allele frequencies) and most of the SNPs were in linkage disequilibrium with each other. A higher frequency of the common alleles of these SNPs was noted for the subjects with JCPsis in comparison with healthy controls. We also identified a haplotype associated with the disease susceptibility. In addition, associations were found between ADAM33 polymorphisms and various cedar pollinosis phenotypes including clinical severity, eosinophil counts in nasal secretion and allergen-specific IgE levels in sera, but not total serum IgE levels. CONCLUSION: These results indicate that polymorphisms in the ADAM33 gene are associated with susceptibility to allergic rhinitis due to Japanese cedar pollen, but the functional relationship still needs clarification.

ADAM Proteins↗

PubMed2004

Effects of lysed Enterococcus faecalis FK-23 on allergen-induced serum antibody responses and active cutaneous anaphylaxis in mice.

BACKGROUND: Our previous studies have presented evidence that lysed Enterococcus faecalis FK-23 (LFK), a lysozyme and heat-treated probiotic product, can inhibit allergen-induced local accumulation of eosinophils in mice. OBJECTIVE: The purpose of this experimental study was to evaluate the influence of orally administrated LFK on the host immune responses. METHODS: BALB/c mice were sensitized subcutaneously, and challenged intraperitoneally by cedar pollen allergen. Blood and spleen samples were collected after oral administration of LFK 60 mg/day for 21 days. The serum levels of total and allergen-specific IgE and IgG2a antibodies and the production of IL-4, IL-5 and IFN-gamma generated by allergen-stimulated cultured splenocytes were determined. Additionally, the effect of LFK on active cutaneous anaphylaxis (ACA) induced by ovalbumin (OVA) challenge in mice was measured after 28 days LFK treatment. RESULTS: No significant differences in serum immunoglobulin levels, as well as in cytokine production of splenocytes were observed between LFK-treated and control mice (P>0.05). There was, however, an increasing tendency of allergen-specific IgG2a level in mice after LFK treatment for 21 days compared with controls (P=0.060). Furthermore, the serum ratio of specific IgE to IgG2a was found to be significantly decreased in the LFK group (P=0.005). In addition, a significant inhibition of OVA-induced ACA reaction was observed in mice that had been fed for 28 days with LFK compared with control mice (P=0.008). CONCLUSION: These results suggest that LFK shows an anti-inflammatory effect, which may be part of the mechanism for protection against IgE-mediated allergy.

Administration, Oral↗

PubMed2004

Susceptibilities of Neisseria gonorrhoeae to fluoroquinolones and other antimicrobial agents in Hyogo and Osaka, Japan.

OBJECTIVES: Decreasing susceptibility of Neisseria gonorrhoeae to fluoroquinolones has been reported in several countries. Knowledge of local N gonorrhoeae susceptibilities to various antimicrobials is important for establishing a rational treatment strategy in each region. METHODS: Isolates of N gonorrhoeae from male urethritis patients attending four urological clinics in Hyogo and Osaka prefectures in Japan were collected during 2002. The MICs for nine antimicrobials: penicillin G, tetracycline, cefixime, ceftriaxone, levofloxacin, gatifloxacin, ciprofloxacin, moxifloxacin, and spectinomycin were determined for each isolate. All isolates were also tested for beta lactamase producing profiles. RESULTS: Among the 87 isolates obtained, only one isolate was revealed to produce beta lactamase. MIC90 values for ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin were over 8 microg/ml, over 8 microg/ml, 4 microg/ml, and 2 microg/ml, respectively. The proportion of isolates resistant to fluoroquinolones was over 60% (ciprofloxacin, 70.1%; levofloxacin, 65.5%; gatifloxacin, 70.1%). Chromosomally mediated penicillin and tetracycline resistance was identified in 12.6% and 33.3% of the isolates. MIC90 values for cefixime and ceftriaxone and were 0.5 microg/ml and 0.0063 microg/ml. All isolates were sensitive to ceftriaxone and 90.8% of them were sensitive to cefixime. MIC90 for spectinomycin was 32 microg/ml and all isolates were sensitive to it. Fluoroquinolone resistance correlated significantly with MICs for penicillin G but not tetracycline. CONCLUSION: Ceftriaxone and spectinomycin demonstrated lower MICs and so are recommended for N gonorrhoeae. Susceptibilities of N gonorrhoeae should be monitored periodically by region.

Anti-Bacterial Agents↗

PubMed2004

Lysed enterococcus faecalis FK-23 oral administration reveals inverse association between tuberculin responses and clinical manifestations in perennial allergic rhinitis: a pilot study.

BACKGROUND: The interest in anti-allergy immunoregulation by lactic acid bacteria (LAB) has been growing over the last few decades. There is evidence to suggest that lysed Enterococcus faecalis FK-23 (LFK), a kind of LAB preparation, could relieve the clinical symptoms of Japanese cedar pollinosis. However, little is known about how LFK plays a role in combating allergy. OBJECTIVE: The aim of this study was to clarify whether improvement of clinical manifestations is associated with enhancement of tuberculin responses in patients with allergic rhinitis treated by LFK. METHODS: One gram of LFK per day was administered orally to fifty perennial allergic rhinitis patients in an open trial that lasted 28 days. Nasal symptoms and sign scores were rated before and after administration of LFK. Tuberculin responses and peripheral blood cells were also measured before and after LFK treatment. RESULTS: Purified protein derivative (PPD) skin test diameter was 2.14 +/- 2.14 mm before LFK administration versus 7.26 +/- 4.81 mm at day 31 (p < 0.01). A significant inverse correlation was recognized between PPD skin test diameters and total nasal scores in the nasal provocation test before and after treatment (r= - 0.600, p < 0.001). Peripheral blood eosinophils were 248 +/- 149 cells/ml before LFK administration and then they significantly decreased to 76 +/- 98 cells/microl (p < 0.01). CONCLUSIONS: These finding may be interpreted as a result of improved clinical symptoms in allergic rhinitis after LFK oral treatment owing to the enhanced host's Th1-type immune responses and supression of the over-expression of Th2-dominated allergic responses.

Administration, Oral↗

PubMed2003

Effect of lysed Enterococcus faecalis FK-23 (LFK) on allergen-induced peritoneal accumulation of eosinophils in mice.

BACKGROUND: The interest in anti-allergy immunoregulation by lactic acid bacteria has been growing for the last few decades. There is some evidence to suggest that lysed Enterococcus faecalis FK-23 (LFK) could relieve the clinical symptoms of pollinosis. However, the mechanism responsible for this phenomenon remains unknown. OBJECTIVE: To identify the effect of LFK, a lysozyme treated and heat-killed preparation from the lactic acid bacteria Enterococcus faecalis FK-23 strain, on allergen-induced eosinophil accumulation. METHODS: BALB/c mice were sensitized with ragweed pollen extract, and peritoneal accumulation of eosinophils was induced. A total of 60 mg (0.5 mL) LFK was orally administered to the experimental mouse every day during 21 days of the sensitization period. In addition, LFK 4 mg, 25 mg and 60 mg (each 0.5 mL) were also orally administered to a mouse of each group every day for 21 days. Saline was fed in a dose of 0.5 mL/mouse per day for the same duration as a control. RESULTS: Compared with control mice, LFK-treated mice exhibited decreased ragweed pollen allergen-induced peritoneal accumulation of eosinophils (P = 0.013), which showed a tendency to be in a dose-dependent fashion (P = 0.14). CONCLUSION: The results provide laboratory evidence of the role for LFK, a lactic acid bacteria preparation, in combating eosinophil accumulation.

Administration, Oral↗

PubMed2003

The growth inhibitory effect of p21 adenovirus on androgen-dependent and -independent human prostate cancer cells.

OBJECTIVE: To assess the potential of p21 as a gene therapy treatment for prostate cancer, by introducing p21 into both androgen-dependent (AD) and -independent (AI) human prostate cancer cell lines via a recombinant adenoviral vector, Ad5CMV-p21, carrying human p21 cDNA. MATERIALS AND METHODS: The LNCaP, DU145 and PC-3 human prostate cancer cell lines were cultured and infected with Ad5CMV-p21. Cell growth, cell-cycle progression and tumorigenicity were then assessed by thymidine incorporation into cellular DNA, and cell number, flow cytometry, and tumour growth after inoculating the cells into nude mice. RESULTS: Growth was inhibited in Ad5CMV-p21 viral-infected AD and AI prostate cancer cells. The effects were dose-dependent, regardless of the androgen status of the cell lines. Flow cytometric analysis showed that Ad5CMV-p21 arrested cell-cycle progression at G1/S with no appreciable effect on the levels of apoptotic cells. The tumorigenicity of cancer cells infected with Ad5CMV-p21 was greatly reduced in athymic mice. CONCLUSIONS: These results suggest that Ad5CMV-p21 may be a new therapeutic agent for human prostate cancer gene therapy.

Adenoviridae↗

PubMed2002

A novel murine myotonia congenita without molecular defects in the ClC-1 and the SCN4A.

The authors report a new murine model for myotonia congenita designated as B6MT. This line spontaneously arose from breeding of transgenic C57BL/6CrSlc mice, irrelevant of the transgene. The B6MT mouse showed moderate to severe action myotonia, and electromyography revealed myotonic discharge. The phenotype was transmitted with autosomal recessive inheritance. Molecular genetic study of the ClC-1 and the SCN4A genes revealed polymorphism with no functional consequences.

Amino Acid Substitution↗

PubMed2002

Low molecular weight PTP-IL-4RA interaction in atopy predisposition.

We recently described a protective effect of the low molecular weight protein tyrosine phosphatase (LMPTP) BC genotype, associated with the highest total enzymatic activity, against high serum IgE levels both in the English and the Italian populations. Here we test the hypothesis of a role of LMPTP in the negative modulation of IL-4 signal transduction checking for genetic interaction between interleukin-4 receptor alpha chain (IL-4RA) genetic polymorphisms and LMPTP polymorphism in the predisposition to high total IgE levels in the English population. We find a significant interaction between LMPTP polymorphism and the intracellular Gln/Arg polymorphism in position 551 of IL-4RA. Our data support the hypothesis of a direct or indirect biochemical interaction between LMPTP and IL-4RA resulting in different modulation of IL-4 signal transduction among joint genotypes.

Asthma↗

PubMed2002

IL-4 receptor alpha chain genetic polymorphism and total IgE levels in the English population: two-locus haplotypes are more informative than individual SNPs.

The IL-4RA locus encodes for the alpha chain of the IL-4 receptor, and is both a functional and positional candidate gene for atopy and allergic disease. Recently Ober et al. have shown that the study of haplotypes at multiple loci in the IL-4RA gene could be more informative than the separate study of single nucleotide polymorphisms (SNPs). One hundred and fifty subjects affected by atopic asthma and 150 healthy control subjects were studied in the English population (Oxford district). Subjects and controls were genotyped for the Ile50Val, Ser478Pro and Gln551Arg polymorphism of the IL-4 receptor alpha chain. The distribution of haplotypes 50-478 shows a highly significant association with IgE levels. In particular, the haplotype Val50/Pro478 is much less frequent in subjects with IgE levels > 100 U mL-1 than in those with IgE levels < 100 U mL-1. Furthermore, the distribution of haplotype 50-551 shows a weak association with IgE levels that is lacking for 478-551 haplotypes. A lower frequency of the Val50/Pro478 haplotype is also observed among asthmatic subjects as compared to healthy controls. With regard to individual SNPs (50 478 and 551), no significant association has been observed with IgE levels or with asthma, thus confirming the higher informative value of the haplotype analysis as compared to separate study on SNPs.

England↗

PubMed2002

Human periodontal ligament cells derived from deciduous teeth induce osteoclastogenesis in vitro.

The receptor activator of NF-kappa B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG), are the important proteins involved in osteoclastogenesis. In this study, we investigated the expressions of RANKL and OPG in cultured human periodontal ligament cells derived from deciduous teeth (DPDL cells) and their roles in osteoclastogenesis. Northern blotting revealed that the OPG mRNA was down-regulated by application of 10(-8) M 1 alpha, 25(OH)2 vitamin D3 [1,25-(OH)2D3] and 10(-7) M dexamethasone (Dex). In contrast, RANKL mRNA was up-regulated by the same treatment. Western blotting demonstrated a decrease in OPG following application of 1, 25-(OH)2D3 and Dex. Tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells (MNCs) were induced when DPDL cells were co-cultured with mouse bone marrow cells in the presence of 1,25-(OH)2D3 and Dex. TRAP-positive MNCs increased significantly when the DPDL cells were co-cultured with bone marrow cells in the presence of anti-human OPG antibody together with 1, 25-(OH)2D3 and Dex. These results indicate that PDL cells derived from deciduous teeth synthesize both RANKL and OPG and could regulate the differentiation of osteoclasts.

Animals↗

PubMed2002

Autosomal-dominant hypoplastic form of amelogenesis imperfecta caused by an enamelin gene mutation at the exon-intron boundary.

Amelogenesis imperfecta (AI) is currently classified into 14 distinct subtypes based on various phenotypic criteria; however, the gene responsible for each phenotype has not been defined. We performed molecular genetic studies on a Japanese family with a possible autosomal-dominant form of AI. Previous studies have mapped an autosomal-dominant human AI locus to chromosome 4q11-q21, where two candidate genes, ameloblastin and enamelin, are located. We studied AI patients in this family, focusing on these genes, and found a mutation in the enamelin gene. The mutation detected was a heterozygous, single-G deletion within a series of 7 G residues at the exon 9-intron 9 boundary of the enamelin gene. The mutation was detected only in AI patients in the family and was not detected in other unaffected family members or control individuals. The male proband and his brother showed hypoplastic enamel in both their deciduous and permanent teeth, and their father showed local hypoplastic defects in the enamel of his permanent teeth. The clinical phenotype of these patients is similar to that of the first report of AI caused by an enamelin gene mutation. Thus, heterogeneous mutations in the enamelin gene are responsible for an autosomal-dominant hypoplastic form of AI.

Amelogenesis Imperfecta↗

PubMed2001

Additional gene therapy with Ad5CMV-p53 enhanced the efficacy of radiotherapy in human prostate cancer cells.

PURPOSE: The aim of this study was to investigate the efficacy of combination therapy of ionizing radiation (IR) and adenoviral p53 gene therapy and to evaluate its molecular mechanisms. METHODS AND MATERIALS: Two human prostate cancer cell lines, DU145 and PC-3 cells, containing different types of p53 gene mutations, were investigated. The recombinant adenovirus vector containing the wild-type p53 gene (Ad5CMV-p53) was used for this study. Cells were irradiated (in 0, 2, 4, and 6 Gy, 300 cGy/min) and after 12 h of irradiation, the cells were infected with various doses of Ad5CMV-p53 (0-40 multiplicity of infection [MOI]). Cytotoxicity was determined by clonogenic assay. The molecular mechanisms were evaluated by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), apoptotic cell detection, and cell cycle analysis. RESULTS: The cell growth inhibition in DU145 (p53-mutated) cells by IR was strongly enhanced by additional Ad5CMV-p53 infection in a viral dose-dependent manner. In DU145 cells, IR alone induced minimal p53 mRNA expression. However, IR combined with Ad5CMV-p53 infection stimulated significant increase in p53 mRNA expression supplemented with Bax and p21 mRNA expressions. In PC-3 (p53-null), IR induced Bax and p21 mRNA expression, while the combination effects were observed in p53, Bax, and p21 mRNA expression. Apoptotic cell deaths were rarely observed after IR alone (DU145: 3%, PC-3: 5%). However, after combination therapy, the proportion of apoptotic cells greatly increased (sevenfold in DU145 cells, and twice in PC-3 cells). G1 cell cycle arrest was observed after Ad5CMV-p53 infection and the combination in both cell lines. CONCLUSION: In this study, we demonstrated that the combination of IR and Ad5CMV-p53 gene therapy resulted in remarkable synergistic effects in human prostate cancer cells. This combination therapy could be one of the optimal treatment strategies for radioresistant prostate cancer.

Adenoviridae↗