Biomedical subjects

Y Ohsaki

Publications and source records attributed to Y Ohsaki.

131 records · Page 8Linked to original sources

PubMedDate not supplied

The distribution of fibronectin and laminin in the murine periodontal membrane, indicating possible functional roles in the apical migration of the junctional epithelium.

Periodontal tissue shows various morphological changes with ageing. A typical example of these changes is the apical migration of the junctional epithelium. The distribution of fibronectin and laminin was investigated by immunofluorescent and immunoelectron-microscope methods in mice to clarify any possible functional roles of these proteins in the apical migration of junctional epithelium. Apical migration begins in 20-week-old mice, and then progresses with increasing age until the mice reach 80 weeks. In the apical tip of the junctional epithelium, fibronectin was demonstrated in the sub-epithelial fibrillar matrix, preceding the progression of apical migration. Fibronectin was also demonstrated in association with the stromal side of focal contacts between epithelial cells and basement membrane. Therefore, these focal contacts are assumed to be fibronectin receptors. There was no apparent relation between the localization of laminin and the migration of the junctional epithelium. These results suggest that the fibronectin provides a provisional matrix for the apical migration of junctional epithelium, but laminin does not appear to play a major part in that migration.

Aging↗

PubMedDate not supplied

Expression of syndecan-1 is common in human lung cancers independent of expression of epidermal growth factor receptor.

In order to determine syndecan-1 expression in lung cancer, we examined 115 lung cancer specimens and 17 lung cancer cell lines. Syndecan-1 was immunohistochemically stained with a polyclonal antibody in 115 paraffin-embedded specimens; 84 cases out of 97 non-small cell lung cancer (NSCLC) and eight cases out of 18 small cell lung cancer (SCLC) were positively stained. Simultaneously, epidermal growth-factor receptor (EGFR) was stained; 47 cases out of 97 NSCLC and one case of 18 SCLC were positively stained. No significant correlation was shown between EGFR and syndecan-1 expression (P=0.68). Syndecan-1 mRNA was detectable in 16 of 17 lung cancer cell lines and EGFR mRNA in nine of 17. Eight cell lines had syndecan-1 mRNA as well as EGFR mRNA. PR-39 (1 microM) and 80 pM transforming growth factor-beta(1) (TGF-beta(1)), did not increase expressions of syndecan-1 mRNA and EGFR in five lung cancer cell lines. We concluded that lung cancer had detectable syndecan-1; however, expression of syndecan-1 protein did not correlate with survival time of lung cancer patients.

Aged↗

PubMedDate not supplied

Pentoxifylline potentiates the antitumor effect of cisplatin and etoposide on human lung cancer cell lines.

The effect of pentoxifylline (PENT) on the sensitivity of two human lung adenocarcinoma cell lines, PC-9 and PC-14, to cisplatin (CDDP) and etoposide (ET) was studied. PENT at 0.5 and 1 mM enhanced the cytotoxicity of CDDP and ET on PC-14 and PC-9, respectively. Isobologram analyses of IC50 data, as well as combination index calculations, revealed that PENT had an additive or a synergistic effect when applied in combination with CDDP or ET, respectively. PENT potentiated the antitumor effect of ET in a nude-mouse xenograft model using PC-14 cells, when PENT was administered at 150 mg/kg subcutaneously for 6 days. Flow cytometry revealed that PENT decreased the accumulation of cells in the G2+M phase caused by CDDP when using PC-9 cells. However, PENT did not remarkably alter the accumulation of cells in G2+M caused by ET. These results suggest that PENT enhanced the antitumor effects of CDDP additively and those of ET synergistically. The enhancement mechanism probably differs between CDDP and ET. PENT needs more study to elucidate its potency as a new agent for combination chemotherapy.

Adenocarcinoma↗

PubMedDate not supplied

Suramin inhibits the growth of non-small-cell lung cancer cells that express the epidermal growth factor receptor.

The epidermal growth factor (EGF) is a potent growth factor that is believed to enhance the proliferation of cancer cells by a paracrine or autocrine mechanism. EGF transduces various signals and finally stimulates cell proliferation upon binding to cell surface receptors. Prevention of the association of this peptide with its receptors might lead to the development of new modalities for treatment of lung cancer. Several investigators have reported that suramin has antiproliferative activity against cancer cells that express EGF receptors (EGF-R), and that it acts by blocking the binding of the ligand to its receptor. In this study, we analyzed the antitumor effect of suramin using two lines of lung cancer cells (A549 and PC-13), which express EGF-R, and a variety of assays. Receptor-binding assays confirmed that A549 and PC-13 cells have cell surface receptors for EGF. Suramin inhibited the binding of EGF to these receptors. EGF and fetal bovine serum (FBS) stimulated the proliferation of cells, but suramin inhibited these effects in a dose-dependent fashion. Suramin at 200 microg/ml reduced the growth of A549 and PC-13 cells by 25 and 15%, respectively, in medium that contained 1% FBS. Paradoxically, the concentrations of suramin that inhibited cell proliferation were lower than those that were effective in inhibiting the binding of EGF to its receptor. Although expression of c-fos and c-myc mRNA increased when cells were stimulated by EGF or FBS, suramin at 200 microg/ml did not markedly alter such expression. Suramin partially blocked the EGF-induced progression of the cell cycle from the G0/G1 to the S phase. These results suggest that suramin partially blocks EGF signal transduction. Suramin probably inhibits cell proliferation by inhibiting intranuclear enzymes, as well as by partial blockage of EGF signal transduction.

Anticarcinogenic Agents↗

PubMedDate not supplied

Epidermal growth factor receptor expression correlates with poor prognosis in non-small cell lung cancer patients with p53 overexpression.

To determine whether cancer patients with tumor suppressor gene abnormality survive for a shorter time when their growth was stimulated by growth factors, we examined 290 non-small cell lung cancer (NSCLC) specimens for p53 and epidermal growth factor receptor (EGFR) protein expressions using immunohistochemical staining. The distribution of cases by pathological stage of tumor was 155 cases of stage I, 30 cases of stage II, 96 cases of stage III and 9 cases of stage IV. Pathological types were 142 adenocarcinomas, 127 squamous cell carcinomas, 17 large cell carcinomas and 4 other types of malignancy. Immunohistochemical staining was performed on the formalin fixed, paraffin-embedded materials with monoclonal antibodies DO-7 and clone EGFR.133. positive staining for EGFR was seen in 124 (42.8%) cases. More EGFR positive cases were found in squamous cell carcinomas than in non-squamous cell carcinomas (p=0.0121). Staining for p53 protein was observed in 147 (50.7%) specimens. Multivariate proportional hazard model analyses revealed EGFR protein expression as a risk factor in the patients with NSCLC (p=0.0240). Patients negative for both EGFR and p53 survived for a longer period of time (p=0.0427).

Adenocarcinoma↗