Biomedical subjects

H Yokozaki

Publications and source records attributed to H Yokozaki.

At least 19 recordsLinked to original sources

PubMed2000

Effect of 9-cis-retinoic acid on oral squamous cell carcinoma cell lines.

Retinoic acid (RA) has been shown to be effective in suppressing premalignant lesions and preventing second primary malignancies in patients cured of squamous cell carcinoma of the head and neck. However, the precise mechanisms of these effects are still uncertain. In the present study, we examined the effect of 9-cis-RA on the growth of six oral cancer cell lines (HSC-2, HSC-3, HSC-4, Ca9-22, Ho-1-N-1 and Ho-1-u-1). In addition, the relationship among growth and differentiation of tumor cells, RA responsiveness and the expression of nuclear retinoic acid receptors were also investigated. Among the six cell lines examined, five (HSC-2, HSC-3, HSC-4, Ca9-22 and Ho-1-u-1) displayed growth inhibition after treatment with 1x10(-6) M 9-cis-RA, while Ho-1-N-1 cells were resistant to 9-cis-RA. The expression level of RARbeta in 9-cis-RA resistant Ho-1-N-1 cells was very low in comparison with the sensitive cell lines. On the other hand, all of the six the cell lines expressed RARalpha, RARgamma, and RXRalpha at various levels. 9-cis-RA induced accumulation of cell population in G1 phase in HSC-3 cells on the 6th day of the treatment, followed by a marked reduction in the levels of hyperphosphorylated pRB, whereas p53 level was not altered. Interestingly, 9-cis-RA induced transiently the expression of p21(Waf1/Cip1), p27(Kip1), p300, CBP, BAX, Bak and bcl-2 proteins, respectively. This effect was associated with reduction of cyclin D1, cdk4 and CDK-activating kinase (cyclin H and cdk7) protein in HSC-3 cells. These results suggest that the growth inhibitory effect of 9-cis-RA on oral squamous cell carcinoma may depend on the expression levels of RARs, especially RARbeta proteins and RXRalpha proteins, and that 9-cis-RA may provide a powerful therapeutic agent for head and neck cancers.

Alitretinoin↗

PubMed2000

DNA hypermethylation at the pS2 promoter region is associated with early stage of stomach carcinogenesis.

pS2, a member of the trefoil peptide family, has been suggested to be a gastric-specific tumor suppressor. We examined the expression of pS2 in gastric carcinomas, adenomas and non-neoplastic mucosa and analyzed the DNA methylation in the pS2 promoter. Reduced expression of pS2 was frequently associated with well-differentiated adenocarcinomas. The CpG sites within the promoter region of the pS2 gene were methylated in pS2-negative gastric carcinoma cell lines whereas it was not in pS2-positive cell line. The promoter methylation was detected in gastric carcinoma tissues and intestinal metaplasia with reduced pS2 expression whereas none of the carcinomas with preserved pS2 expression showed the promoter methylation. These findings suggest that reduced expression of pS2 due to the promoter methylation may participate in an early stage of stomach carcinogenesis, especially of well differentiated type.

Biomarkers, Tumor↗

PubMed2000

Cloning of a human hepatocyte growth factor/scatter factor transcription variant from a gastric cancer cell line HSC-39.

A new transcription variant of hepatocyte growth factor/scatter factor (HGF/SF) was cloned from human gastric cancer cell line HSC-39. Northern blot analysis of eight human gastric cancer cell lines (TMK-1, MKN-1, MKN-7, MKN-28, MKN-45, MKN-74, KATO-III and HSC-39) demonstrated that HSC-39 cells expressed a 1.3 kb abnormal HGF/SF transcript. Screening of 1 x 10(6) colonies of cDNA library from HSC-39 constructed in pAP3neo mammalian expression vector selected four positive clones containing HGF/SF transcript. Among them, two contained a 1.3 kbp insert detecting the identical transcript to that obtained with HGF/SF probe by Northern blotting. Deoxynucleotide sequencing of the 1.3 kbp insert revealed that it was composed of a part of HGF/SF cDNA from exon 14 to exon 18, corresponding to the whole sequence of HGF/SF light chain, with 5' 75 nucleotides unrelated to any sequence involved in HGF/SF.

Base Sequence↗

PubMed1999

Alterations of p73 preferentially occur in gastric adenocarcinomas with foveolar epithelial phenotype.

To establish the possible involvement of p73, a newly discovered p53-related candidate as a tumor-suppressor gene in human stomach carcinogenesis, the allelic status, allele-specific expression and mutations of the gene were investigated using PCR-restriction fragment length polymorphism (PCR-RFLP) analysis, RT-PCR SSCP analysis and direct DNA sequencing in 95 gastric adenocarcinomas. Of these, 32 exhibited the heterozygous p73 allele for the StyI restriction site in exon 2. Among these, the cancer DNA of 12 revealed loss of heterozygosity (LOH) of p73. All of the cancers with p73 LOH exhibited phenotypes of foveolar epithelium of the stomach. RT-PCR SSCP analysis of p73 heterozygous cases demonstrated not only bi-allelic expression of the gene but also relatively reduced expression of the affected allele in 6 of 8 tumors with p73 LOH. No gene mutation was detected in the remaining allele of LOH-positive cancers. Our results suggest that alterations of p73, including LOH and abnormal expression, may play roles in the genesis of foveolar-type gastric adenocarcinomas, though this is not in line with a classical Knudson's "2-hit" model.

Adenocarcinoma↗

PubMed1999

Effect of 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)- quinolinone (vesnarinone) on the growth of gastric cancer cell lines.

Vesnarinone (OPC-8212; 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinone ) is a synthetic oral cardiotonic agent that has been used for the treatment of patients with congestive heart failure. Six days of treatment with 30 microg/ml of vesnarinone induced 20-80% growth inhibitions in five out of six gastric carcinoma cell lines examined. Cell cycle analysis revealed that the vesnarinone-sensitive TMK-1 gastric cancer cell line exhibited a significant G0-G1 arrest without evidence of apoptotic cell death induction after 48 h of treatment. Interestingly, this phenomenon was preceded by a marked reduction in the expression of cyclin A, D1 and E as well as cyclin-dependent kinase 2 (CDK2). On the other hand, no significant change was observed in the expression of p21(Waf1/Cip1), p27Kip1 nor various growth factors and their receptor genes. Overall these results indicate that vesnarinone inhibits the growth of gastric cancer cells by down-regulating G1 cyclins and CDK2 to induce G0-G1 arrest through a pathway different from that of cyclin inactivation by p21(Waf1/Cip1) or p27Kip1.

Antineoplastic Agents↗

PubMed1999

Expression of the E2F family in human gastrointestinal carcinomas.

The E2F family of transcription factors plays a key role in the control of cell-cycle progression. Some family members may act as oncogenes, others as tumor-suppressor genes. The genetic changes and the expression of E2F-1 and -3 were examined in human gastric and colorectal carcinomas by Southern, Northern and Western blots. Gene amplification of E2F-1 was detected in 4% (1/23) of gastric carcinomas and 25% (3/12) of the colorectal carcinomas. Increased expression of E2F-1 mRNA was observed in 40% (12/30) of the gastric carcinomas and in 60% (3/5) of the colorectal carcinomas in comparison with the corresponding non-neoplastic mucosa. Over-expression of E2F-1 protein was confirmed in many of the gastric carcinomas. In contrast, expression levels of E2F-3 mRNA were lower in 70% (21/30) of the gastric carcinomas and in 20% (1/5) of the colorectal carcinomas than in their corresponding normal counterparts, while gross alteration of the E2F-3 gene was not detected. These results suggest that gene amplification and anomalous expression of the E2F gene may permit development of gastrointestinal carcinomas.

Adult↗

PubMed1999

Effect of antisense human telomerase RNA transfection on the growth of human gastric cancer cell lines.

The majority of gastric cancers express high levels of human telomerase template RNA (hTR) that is essential for cellular survival. In this study, we examined whether antisense hTR (ahTR) had a growth inhibitory effect on three gastric cancer cell lines, MKN-1, MKN-28, and TMK-1, through transfection via an ahTR expression vector. Both the ahTR transfected MKN-1 and TMK-1 cells changed morphologically into multinucleate giant cells, and subsequently underwent cell death. Conversely, the ahTR transfected MKN-28 cells survived over 50 PDs in spite of telomere shortening. Surprisingly, high levels of telomerase activity were observed in the telomere-reduced cells. Furthermore, the expression of mRNAs for p21/Waf1/Cip1/Sdi1, IRF-1 and IFN inducible 6-16 was higher in the telomere-reduced cells than in the parental cells. These results suggest overall that the ahTR expression may bring about telomere shorting, leading to cell death or cellular senescence in gastric cancer cells.

Cell Cycle↗

PubMed1999

Overexpression of human telomerase RNA is an early event in oesophageal carcinogenesis.

Telomerase, the ribonucleoprotein enzyme that elongates telomeres, is repressed in normal human somatic cells but is reactivated during tumour progression. The purpose of this study was to investigate the localization of human telomerase RNA (hTR) expression in human oesophageal dysplasia and cancer by using in situ mRNA hybridization (ISH) with avidin-biotin staining. Ki-67 immunoreactivity was also examined. We analysed 51 squamous cell carcinomas, 9 dysplasias and 60 normal mucosae. The integrity of the mRNA in each sample was verified by using a poly d(T)20 probe. Seventy-six samples (63%) showed no mRNA degradation; these included 30 carcinomas, 7 dysplasias and 39 normal mucosae. At the single-cell level, high levels of hTR expression were found in the cytoplasm and especially in the nucleus. Most (>90%) cancer cells demonstrated high levels of hTR expression in 29 (97%) of the 30 tumours. Most dysplastic cells also showed high levels of hTR in all 7 dysplastic cases. In all 39 normal mucosae, most basal cells indicated high levels of hTR expression, which were also seen in infiltrating lymphocytes. The distribution of hTR-expressing cells was similar to that of Ki-67-positive cells. These data suggest that overexpression of hTR may be correlated with the proliferative activity that defined by Ki-67 immunoreactivity and is an early event in carcinogenesis of the oesophagus.

Esophageal Neoplasms↗

PubMed1999

Transfection of interleukin-8 increases angiogenesis and tumorigenesis of human gastric carcinoma cells in nude mice.

The growth and spread of tumour cells depends on adequate vasculature. We have previously reported that the expression of interleukin-8 (IL-8) directly correlates with the vascularity of human gastric carcinomas. To provide evidence for a causal role of IL-8 in angiogenesis and tumorigenicity of human gastric cancer, we used the lipofectin method to stably transfect the human TMK-1 gastric carcinoma cells (low endogenous IL-8) with an IL-8 expression vector or control vector. Transfection with IL-8 did not affect the proliferation of cultured cells, yet the culture supernatants of the transfected (but not control) cells stimulated proliferation of human umbilical vein endothelial cells. The IL-8-transfected and control cells were injected into the gastric wall of nude mice. IL-8-transfected cells produced rapidly growing, highly vascular neoplasms as compared to control cells. These results provide direct evidence for the role of IL-8 in the angiogenesis and tumorigenicity of human gastric carcinomas.

Animals↗

PubMed1999

Cutaneous ciliated cyst of the right lower leg.

A 23-year-old Japanese woman with a cutaneous ciliated cyst on her right lower leg is reported. A subcutaneous cyst, measuring 2.5 cm in diameter with papillary projections into the lumen, was lined with ciliated cuboidal to columnar epithelia with partial stratification, histologically. These lining cells did not produce mucin. Immunohistochemically, the ciliated lining cells of the cyst were diffusely positive to epithelial membrane antigen and cytokeratin. In addition, positive immunoreaction with anti-desmin monoclonal antibody was observed in the body of the cilia. Less than 10% of the epithelial cells revealed positive immunoreaction to S-100 protein and estrogen receptor.

Adult↗

PubMed1999

Molecular-pathological diagnosis of gastrointestinal tissues and its contribution to cancer histopathology.

Multiple genetic and epigenetic alterations of cancer-related genes and molecules are involved in the course of the development and progression of gastrointestinal cancers. These include telomerase activation, genetic instability, and abnormalities of oncogenes, tumor suppressor genes, cell cycle regulators, cell adhesion molecules and DNA repair genes. By analyzing these alterations in pathology specimens, we can improve differential diagnosis of cancer, obtain information of grade of malignancy, and identify patients at high risk for developing multiple primary cancers. Since 1993, a system of molecular-pathological diagnosis was established, and has been performed as a routine service in collaboration with Hiroshima City Medical Association Clinical Laboratory. More than 10 000 cases of gastrointestinal biopsy and surgery have been analyzed, and additional information of differential diagnosis, biological malignancy and tumor multiplicity could be obtained. Molecular-pathological diagnosis may provide a new approach to cancer diagnosis and novel therapeutics for the 21st century. Furthermore, the analysis of the genetic and epigenetic abnormalities in clinical materials may clarify the molecular mechanism of carcinogenesis and comparative morphological changes. From the analyses of p27KIP1 and telomerase in gastrointestinal adenomas, we have learned that morphological abnormality of the nucleus is an indicator for cells with immortality and malignant potential that must participate in super-early diagnosis (detection of true precancerous lesions) of gastrointestinal cancer. Molecular-pathological diagnosis thus contributes to detailed understanding of cancer histopathology and improves the histopathological diagnosis.

Adenocarcinoma↗

PubMed1999

Idiopathic granulomatous meningoencephalitis presenting as an intracranial tumor.

A 2-year-old girl presented with a single episode of generalized seizure. Magnetic resonance imaging examination showed an intracranial mass with a diameter of 2.5 cm in the right parieto-occipital region of the cerebrum. These clinicoradiological findings were suggestive of intracranial tumor. Histologically, fibroblastic proliferation of storiform pattern was noted, associated with epithelioid granulomas. The etiological pathogens for the granulomas could not be detected even though investigation of special histochemical staining, immunohistochemical study and DNA analysis of Mycobacterium tuberculosis by polymerase chain reaction technique was performed. On electron microscopic examination, the area appearing as a storiform pattern consisted of fibroblasts showing much dilated rough endoplasmic reticulum and slender tappering cytoplasmic processes without cellular junctional complex. No organisms were identified in the granulomatous area of the lesion. From those findings the diagnosis as idiopathic granulomatous meningoencephalitis was made.

Biomarkers↗

PubMed1999

No mutations of the Smad2 gene in human sporadic gastric carcinomas.

BACKGROUND: The majority of cancer cells escape from TGF-beta-mediated growth control. However, the mechanism of resistance to the growth inhibitory effects by TGF-beta is not clear. TGF-beta signaling is initiated when the type I receptor phosphorylates the SMAD proteins, Smad2 and Smad3. Recently, mutations of Smad2 have been detected in human colon and lung cancers. Mutation of coding sequences of Smad2 in gastric carcinomas has not yet been elucidated adequately. METHODS: PCR-SSCP analysis of the entire coding region of Smad2 in 35 human sporadic gastric cancers and eight gastric cancer cell lines was performed using 11 sets of intron-based primers. RESULTS: No mutations of Smad2 were detected in any tumor or cell line. CONCLUSIONS: The results suggest that mutation of Smad2 does not play a key role in human stomach carcinogenesis.

DNA-Binding Proteins↗

PubMed1999

Silencing of the CD44 gene by CpG methylation in a human gastric carcinoma cell line.

We analyzed 8 human gastric carcinoma cell lines for the expression of CD44 by northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR), and identified 1 cell line MKN-28 that did not express CD44. In an attempt to clarify the mechanism responsible for the inactivation of CD44 gene expression in this cell line, we investigated the methylation status around the promoter region of CD44 gene by digestion of the DNA with the methylation-sensitive restriction enzyme HpaII. The promoter region of CD44 in MKN-28 revealed hypermethylation, whereas other CD44-positive cell lines did not. Furthermore, treatment of MKN-28 with the demethylating agent 5-azacytidine restored the expression of the gene. These results suggest that CD44 expression is controlled by a DNA hypermethylation mechanism in MKN-28.

DNA Methylation↗

PubMed1999

Microsatellite instability and hMSH2 gene mutation in a triple cancer (colon cancer, endometrial cancer, ovarian cancer) patient in hereditary non-polyposis colorectal cancer (HNPCC) kindred.

A patient who had triple cancer (colon cancer, endometrial cancer, and ovarian cancer) in HNPCC kindred is reported. Her family history revealed the occurrence of colon cancer in her paternal aunt and in two cousins, fulfilling the minimum HNPCC criteria. Microsatellite instability analysis revealed replication error (RER)+ in all cancer lesions at 2 microsatellite loci (D1S191, BAT 40). SSCP analysis suggested germline mutation in exon 2 of the hMSH2 gene. This case showed the importance of complete family-history investigations to identify HNPCC patients. In the near future, definitive diagnosis of HNPCC will be possible on the basis of DNA studies.

Adenocarcinoma↗

PubMed1999

Allele frequency of D17S855 microsatellite locus in Japanese people.

Allele frequency of D17S855 microsatellite locus, an intragenic polymorphic cytosine-adenine repeat located in the BRCA1 gene, was analyzed in 456 normal tissues of Japanese adults. The frequency of D17S855 microsatellite polymorphism was 77.9% (335/456). The size of D17S855 PCR fragments ranged from 137 to 157 bp. The most frequent allele was 151 bp (29.9%) followed by 149-bp (19.3%), 145-bp (17.5%), and 147-bp (17.0%) fragments. The observed allele distribution of this microsatellite was similar to that of Southern Swedes, while it was quite different from that of European Caucasian specimens deposited in the Genome Database.

Adult↗

PubMed1999

Allele frequency of D1S191 microsatellite locus in Japanese people.

The allele frequency of D1S191 microsatellite locus was analyzed in 398 normal tissues of Japanese adults. The frequency of D1S191 microsatellite polymorphism was 90.2% (359/398). The size of D1S191 PCR fragments ranged from 147 bp to 169 bp. The most frequent allele in the Japanese subjects was 161 bp (34.1%) followed by 159 bp (27.9%), 163 bp (17.7%), and 157 bp (12.4%) fragments. The observed allelic distribution of this microsatellite in the Japanese subjects was similar to that of European Caucasians deposited in the Genome Database.

Adult↗

PubMed1999

Microsatellite instabilities in gastric cancer patients with multiple primary cancers.

To answer whether microsatellite instability (MSI) can serve as a molecular marker for the risk-assessment of the development of multiple cancers, 26 tumors from 10 gastric cancer cases with multiple primary cancers were investigated. Six out of 10 cases revealed MSI in one or more cancer DNA. Significant statistical association was observed between MSI positive gastric cancer and cancer multiplicity (chi2 test, P<0.05). The complicated primary tumors in MSI-positive cases arose in colorectum, urogenital tract and ovary, which mimicked the tumor spectrum of hereditary non-polyposis colorectal cancer (HNPCC). On the other hand, most of the multiple cancers in MSI negative group were found synchronously and limited to the digestive organs. These observations suggest that MSI test on gastric cancer may be considered as a good marker for the assessment of multiple cancer development especially in the sites where tumors of HNPCC usually develop.

Aged↗