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Masachika Fujiwara

Publications and source records attributed to Masachika Fujiwara.

13 recordsLinked to original sources
PubMed2006

Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R.

Telomere maintenance can occur in the absence of telomerase by a mechanism referred to as alternative lengthening of telomeres (ALT). ALT is considered to be rare in tumors of epithelial origin. The biological significance and molecular mechanism of ALT have not been well studied in human cancers. It has been reported that clinical samples of adrenocortical carcinoma show a low incidence of telomerase positivity. We characterized an adrenocortical carcinoma cell line, H295R, focusing on the telomere maintenance mechanism, and compared it with telomerase-positive 293 cells and HeLa cells. Telomerase activity could not be detected in H295R cells by the TRAP assay. Among the essential components of the telomerase holoenzyme, only hTERT expression was undetectable by RT-PCR, indicating that the lack of telomerase activity is due to suppression of hTERT. H295R cells had long and heterogeneous telomere DNA, and FISH revealed large nuclear bodies in a few interphase nuclei, which presumably represented ALT-associated PML bodies. These results suggest that H295R cells have the ALT phenotype. Several proteins that are possibly associated with the telomere maintenance mechanism were examined. TRF1 and TRF2 were expressed in H295R cells as well as in 293 cells and HeLa cells. The ratio of hnRNP B1 to A2 was higher in H295R cells than in 293 cells and HeLa cells. In conclusion, the H295R adrenocortical carcinoma cell line is negative for telomerase and maintains its telomeres by the ALT mechanism. We anticipate that H295R cells will be a good model for understanding the significance and mechanism of ALT in human cancers.

Adrenal Cortex Neoplasms↗
PubMed2005

Histiocytoid breast carcinoma: solid variant of invasive lobular carcinoma with decreased expression of both E-cadherin and CD44 epithelial variant.

Histiocytoid breast carcinoma (HBC) is a rare type of breast carcinoma with morphologic characteristics resembling those of histiocytes. Described herein are cytological and histological findings in a case of HBC. Fine-needle aspiration cytology revealed numerous loosely cohesive tumor cells with abundant foamy to granular cytoplasm and bland-appearing nuclei. The resected tumor exhibited a solid growth pattern instead of classic invasive lobular patterns observed in most reported cases of HBC. However, distinct intracytoplasmic lumina and Pagetoid extension to ducts suggested that this tumor was a variant of invasive lobular carcinoma. To determine the cause of the loose cellular cohesiveness of this HBC, its expression of the epithelium-related cell adhesion molecules E-cadherin and CD44v8-10 (CD44 epithelial variant) was examined. Immunohistochemically, E-cadherin was not detected, similar to most lobular carcinomas. Furthermore, competitive reverse transcription-polymerase chain reaction (RT-PCR) analyses among alternatively spliced variants of CD44 revealed that the ratio of expression of CD44v8-10 to that of CD44v10 (dominant variant in leukocytes) was lower than that for the reference breast carcinoma samples. It is concluded that the present case of HBC was a solid variant of invasive lobular carcinoma exhibiting foamy to granular cytoplasmic change. Decreased expression of both E-cadherin and CD44 epithelial variant may be responsible for the loose cellular cohesiveness observed in HBC.

Aged↗
PubMed2005

Altered expression patterns of heterogeneous nuclear ribonucleoproteins A2 and B1 in the adrenal cortex.

Several proteins implicated in hormonogenesis of the adrenal cortex have alternatively spliced isoforms, which respond differently to adrenocorticotropic hormone (ACTH). Heterogeneous nuclear ribonucleoproteins A2 and B1 are among the abundant pre-mRNA-binding proteins involved in alternative splicing. We examined the expression of A2 and B1 in normal adrenal cortex and tumors. B1 was variably expressed in the zona fasciculata-reticularis, although A2 was diffusely expressed in the three zones. B1 was more abundant in compact cells than clear cells, and B1 expression was frequent in the zona reticularis, which consists mainly of compact cells. In three kinds of cortical adenomas autonomously producing hormones, B1 was generally overexpressed and there were no significant differences among them. In cortisol-producing tumors, non-tumor parts of the cortex, which were generally atrophic due to low ACTH, had less B1 protein than normal adrenals. These results suggested a correlation between B1 expression and the hormonal activity responding to ACTH. In vitro ACTH stimulation induced a biphasic expression of B1 in an H295R cortical carcinoma cell line, and it paralleled hormonogenesis. Conclusively, B1 expression varied in relation to the hormonal activity responding to the ACTH, and it may provide a key to elucidating the splicing mechanisms involved in hormonogenesis.

Adrenal Cortex↗
PubMed2005

Expression of heterogeneous nuclear ribonucleoproteins A2 and b1 in the thyroid follicular cells.

Several proteins implicated in hormonogenesis of the thyroid have alternatively spliced isoforms. Alternative splicing of pre-mRNA is considered to be important to regulate the hormonal activity. Heterogeneous nuclear ribonucleoproteins (hnRNP) A2 and B1 are two of the abundant nuclear RNA-binding proteins involved in alternative splicing. We examined the expression of hnRNP A2 and B1 in the thyroid, paying particular attention to the relationship between their function and the cellular morphology. B1 was expressed more frequently in cuboidal follicular cells that are hormonally active than in flat follicular cells in normal thyroid, although A2 expression showed no significant difference in two cell types. In Graves' disease, the patients who had high serum levels of triiodothyronine and thyroxine showed significantly increased expression of B1. B1 expression did not differ significantly between normal thyroids and thyroid neoplasms, except undifferentiated (anaplastic) carcinoma. Conclusively, B1 expression varied in relation to hormonal activity in thyroid follicular cells. B1 protein is a good immunohistological marker to detect hormonal activity of follicular cells, and may provide a key to elucidate the splicing mechanisms involved in thyroid hormonogenesis.

Alternative Splicing↗
PubMed2004

Solitary mucosal neuroma of the hard palate: a case report.

Mucosal neuroma is rare neurogenic tumour that arises in the oral cavity as a component of multiple endocrine neoplasia type 2b (MEN 2b). We present the case of a histologically confirmed solitary mucosal neuroma of the hard palate in a 49-year-old woman with no other components of MEN 2b.

Female↗
PubMed2004

Inflammatory pseudotumor-like follicular dendritic cell tumor of the spleen.

A case of so-called inflammatory pseudotumor (IPT), occurring in the spleen of a 77-year-old woman, is reported. The spleen contained a well-circumscribed mass with central hemorrhage and necrosis. Histologically, spindle cells were dispersed in a background of abundant inflammatory cells, predominantly lymphocytes and plasma cells. The cells possessed enlarged, sometimes twisted or irregularly folded, nuclei that contained vesicular chromatin, and small but distinct, centrally located nucleoli. Immunohistochemically, the spindle cells were diffusely positive for vimentin, and focally positive for follicular dendritic cell (FDC) markers (Ber-MAC-DRC for CD35 and CNA.42). The Epstein-Barr virus (EBV) was exclusively detected in the spindle cells by in situ hybridization analysis. The cells also expressed the latent membrane protein-1 (LMP-1) of EBV, and polymerase chain reaction (PCR) analysis revealed that the LMP-1 gene had a 30-bp deletion and three point mutations, although their significance remains controversial. Inflammatory pseudotumor is a descriptive term that encompasses several different entities, and recent investigations have revealed the existence of neoplastic entities among IPT. One of the neoplastic IPT, recently designated 'IPT-like FDC tumor', is characterized by proliferation of EBV-positive FDC and commonly occurs in the liver and spleen. Because such tumors are capable of recurrence and metastasis, it is important to consider the possibility of an IPT-like FDC tumor when making a diagnosis of a hepatic/splenic IPT-like lesion.

Aged↗
PubMed2004

Expression and alternative splicing pattern of human telomerase reverse transcriptase in human lung cancer cells.

Telomerase activity is generally considered to be necessary for cancer cells to avoid senescence. The expression of human telomerase reverse transcriptase (hTERT) is believed to be a rate-limiting step in telomerase activation. Recently, it has been proposed that the alternative splicing of hTERT is also involved in regulation of telomerase activity. However, the regulatory mechanism of telomerase in cancer cells has not been thoroughly investigated. To clarify it in lung cancer cells, we measured the expression of the hTERT transcript, analyzed its alternative splicing by RT-PCR, and compared it with telomerase activity and telomere length. The expression of the hTERT transcript was positively correlated with telomerase activity in lung cancer cells. Cancer cells with high telomerase activity contained 4 splicing variants of hTERT, and the full-length variant was 31.3-54.2% of the total transcripts. Cells of the TKB-20 cell line, which has extremely low telomerase activity, showed a different splicing pattern of hTERT in addition to low expression. The functional full-length variant was scarcely detected in TKB-20 cells, suggesting that the telomerase activity was repressed by alternative splicing of hTERT. Telomere length was not necessarily correlated with telomerase activity or hTERT expression in lung cancer cells. Cells of the TKB-4 cell line that also showed relatively low telomerase activity (as TKB-20 cells) had long telomeres. In conclusion, hTERT expression is regulated at both the transcriptional and post-transcriptional levels in lung cancer cells, and the alternative splicing of hTERT is involved in the control of telomerase activity.

Alternative Splicing↗
PubMed2004

Cell growth after withdrawal of gefitinib ("Iressa", ZD1839) in human lung cancer cells.

Gefitinib ("Iressa", ZD1839) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor, which blocks signal transduction pathways implicated in proliferation and survival of cancer cells. However, in vitro and in vivo studies concerning cell growth after withdrawal of gefitinib are limited. To determine whether cancer cells would resume proliferation upon removal of gefitinib, an in vitro study was undertaken using 4 human non-small cell lung cancer cell lines. With immunocytochemical staining and Western blot analysis, we confirmed positive expression of EGFR in these cell lines. We next evaluated growth inhibition before and after withdrawal of gefitinib. After incubation with 0-100 microM gefitinib for 24 h, medium containing gefitinib was removed, followed by addition of fresh growth medium to cell cultures. MTT assays were performed daily over a 6-day time course. Even at very low levels of gefitinib (<1 microM), these 4 TKB cells had 1-10% growth inhibition, respectively. With these levels of gefitinib, continued inhibitory effects after withdrawal of getitinib were observed in 3 of the 4 cell lines. Furthermore, none of the 4 cell lines, including the cell line which had abolished growth inhibition, showed accelerated re-growth rate after the withdrawal of gefitinib even in these exposure conditions. Based on our in vitro experiments, additional in vivo studies, which can compare the pre- and post-treatment growth rate, will be necessary to help better understand the mechanisms behind cell growth recovery after temporary gefitinib treatment.

Antineoplastic Agents↗
PubMed2004

Expression of hnRNP A2/B1 proteins in small airway epithelial cells.

The overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, especially of B1 has been reported informative to detect pre-clinical lung cancer for early detection. However, relatively little work has been performed on the expression of hnRNP A2/B1 in non-malignant airway cells; such information is clearly required to investigate whether overexpression of this protein could be a specific marker for early lung cancer detection. In order to evaluate whether the expression of hnRNP A2/B1 is specific for cancer cells, we investigated the expression of the protein in human small airway epithelial (HSAE) cells. Using immunostaining and Western blotting with monoclonal antibodies, 4G8 (specifically reacts A2) and 2B2 (specific to B1), expression of hnRNP A2/B1 in HSAE cells was evaluated. Northern blotting and quantitative RT-PCR were also performed. In HSAE cells, hnRNP A2 as well as B1 were expressed primarily in the nucleus excluding the nucleolus, although the expression of A2 protein was weaker than that of B1 protein. Staining pattern of hnRNP A2/B1 in HSAE cells was similar to that observed in control cancer cells. Western blotting with 4G8 and 2B2 apparently demonstrated expression of A2 and B1 in HSAE cells. In Northern blotting, both hnRNP A2 mRNA and B1 mRNA were observed in HSAE cells as shown in control cancer cells. hnRNP A2/B1 was apparently expressed in HSAE cells, although the expression in HSAE cells was weaker than that of cancer cells. More quantitative determination of A2/B1 is required to elucidate their significance in early lung cancer detection.

Blotting, Northern↗
PubMed2003

Angiomyofibroblastoma of the vulva: report of a case with immunohistochemical and molecular analysis.

A 43-year-old woman presented with a mass in the subcutaneous tissue of the right labium majus. A lipoma or Bartholin gland cyst was suspected and excision of the lesion was performed. The lesion was well circumscribed, and histological examination revealed a typical angiomyofibroblastoma. The lesion was composed of alternating hypocellular edematous and hypercellular areas with abundant vessels, and plump tumor cells were loosely dispersed or aggregated mainly around the vessels. Tumor cells were immunoreactive for vimentin and desmin but negative for muscle actins. Ultrastructurally, the tumor cells contained a moderate amount of rough endoplasmic reticulum and abundant intermediate filaments, and had primitive junctions. Pinocytotic vesicles or basal lamina were not evident. Immunohistochemical studies also revealed that the tumor cells expressed basic fibroblast-growth factor, vascular-endothelial-growth factor, and stem-cell factor, factors that may contribute to the rich vascularity and mast cells within the tumor. Reverse transcription-polymerase chain reaction detected high mobility group I-C (HMGI-C) transcripts in the tumor tissue. Because the expression of HMGI-C is regulated by developmental and differentiation processes and is not found in adult normal tissues, HMGI-C may be involved in the tumorigenesis of angiomyofibroblastoma.

Adult↗
PubMed2003

Cytokeratin 19 fragment in patients with nonmalignant respiratory diseases.

STUDY OBJECTIVE: Cytokeratin 19 fragment (CYFRA) is a specific tumor marker in patients with lung cancer; however, it has been reported that serum CYFRA levels are elevated in some patients with nonmalignant respiratory diseases such as interstitial pulmonary fibrosis (IPF) and collagen disease-associated pulmonary fibrosis (CDPF). To investigate the serum CYFRA levels in nonmalignant respiratory diseases in detail, we studied 413 patients with respiratory diseases. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: Four hundred thirteen patients with nonmalignant respiratory diseases and lung cancer. MEASUREMENTS AND RESULTS: Serum CYFRA levels were measured with a commercially available enzyme immunoassay kit. Immunohistochemical study was performed using monoclonal antibody Ks 19.1 (Rosch Diagnosica; Bern, Switzerland) on surgically resected or autopsied lung specimens. Gel electrophoresis and immunoblotting was performed with serum samples. In 149 patients with nonmalignant diseases except IPF and CDPF, the ratio of patients with > 3.5 ng/mL of serum CYFRA was 13.4%. In 13 of 30 patients (43.3%) with IPF and CDPF, the serum CYFRA levels were abnormally elevated. The 95th percentile serum CYFRA level of the patients with nonmalignant respiratory diseases was 6.2 ng/mL, and none of them had CYFRA levels > 20.3 ng/mL. Survival in patients with IPF and CDPF with elevated serum CYFRA levels were significantly lower than in those with normal range (p = 0.0335). Western blotting using serum from nonmalignant lung diseases and patients with lung cancer showed no apparent difference between them. An immunohistochemical study indicated CYFRA was selectively expressed in the pulmonary epithelial cells that covered the remodeling alveolar septi in nonmalignant respiratory disease. CONCLUSION: Serum CYFRA was elevated in some nonmalignant respiratory diseases, especially in IPF and CDPF. The value of serum CYFRA would reflect the severity of lung injury in nonmalignant respiratory diseases and might be related to the prognosis in patients with IPF and CDPF.

Adult↗
PubMedDate not supplied

The intraductal component of breast cancer is poorly responsive to neo-adjuvant chemotherapy.

Neo-adjuvant chemotherapy has been used for locally advanced breast cancers. With special attention to the proportion of intraductal component, we pathologically studied 25 patients that underwent neo-adjuvant chemotherapy via intra-arterial infusion or intravenous injection. In general, neo-adjuvant chemotherapy had a favorable effect on tumor reduction. The effectiveness varies depending on the predominance of intraductal component. The cases with a high proportion of intraductal component had lower response to the chemotherapies. The larger number of cancer cells remained within the mammary ducts. The residual cancer cells conserved proliferative activity. Intraductal component is poorly responsive to neoadjuvant chemotherapy.

Adult↗