Cystatin C expression in ischemic white matter lesions

OBJECTIVES

To study the involvement of cystatin C in the progression of ischemic white matter lesions (WMLs).

MATERIALS AND METHODS

Cystatin C levels in the cerebrospinal fluid (CSF) of patients with cerebrovascular disease, and also in primary and established human neural cell cultures were investigated. For pathologic analysis, cystatin C immunoreactivity was investigated in the white matter of patients with severe WMLs, mild WMLs or controls.

RESULTS

Cystatin C levels in the CSF of patients with Fazekas WML grade 3 [14 with hypertension; W/HT(+) and nine without hypertension; W/HT(-)] were lower than those in 38 patients with grade 0-1 (P = 0.0022 and P < 0.0001 respectively). Immunohistochemical study showed that the cystatin C immunoreactivity was found in astrocytes, and the number of astrocytes in the white matter in the severe WML group was decreased when compared with that in controls (P = 0.0027) and in the mild WML group (P = 0.0024). In human neural cell cultures, treatments with thrombin, matrix metalloproteinases and interleukin 1 beta increased the expression of cystatin C mRNA in human astrocytes and hybrid neurons, but an enzyme-linked immunosorbent assay revealed that only thrombin significantly increased the production and secretion of cystatin C in astrocytes.

CONCLUSIONS

These results suggest that low levels of CSF cystatin C in ischemic WMLs might be due to the decreased number of astrocytes that secrete cystatin C in response to the stimuli of proteases and inflammatory cytokines.

Prognostic role of immunosuppressive acidic protein in patients with esophageal cancer

Immunosuppressive acidic protein (IAP) suppresses several immune responses in vivo and in vitro , and high preoperative IAP levels could predict the impairment of the host's immunity. In this study prognostic significance of preoperative IAP levels was investigated in 68 esophageal cancer patients with curative resection and eight with non-curative resection. The curative group had significantly lower levels than the non-curative group (432 +/- 183 mg/mL vs. 739 +/- 235 mg/mL, P < 0.0001). The IAP levels were associated with T-status (P < 0.0001), lymphatic invasion (P < 0.05), and p-stages (P < 0.0001). When 5-year survival rate of patients with curative resection was compared by setting various cutoff values of IAP between high and low IAP groups, several cutoff points (400-580 mg/mL) were revealed to be significantly associated with survival. Setting cutoff value of IAP to 560 mg/mL resulted in a most significant difference of 5-year survival rate of patients between the high and low IAP groups (13.9% and 61.5%, P < 0.0001). These data indicate that pre-operative IAP level is a useful parameter to predict the prognosis of esophageal cancer patients after curative resection.

Plaque characterisation by Virtual Histology intravascular ultrasound analysis in patients with type 2 diabetes

OBJECTIVES

To evaluate the in-vivo plaque composition and characteristics in patients with type 2 diabetes mellitus (DM) using Virtual Histology intravascular ultrasound (VH IVUS).

METHODS

In 90 patients with stable angina pectoris, de novo target vessels were studied and plaque components were analysed. Patients were divided into two groups: a diabetic group (36 vessels) and a non-diabetic group (54 vessels).

RESULTS

The percentage area of necrotic core and dense calcium were significantly larger in the DM group than the non-DM group (necrotic core: 11.0% (interquartile range (IQR): 7.2-15.2%) vs 7.6% (IQR 5.6-13.2%), p = 0.03; dense calcium: 5.6% (IQR: 2.3-7.3%) vs 2.9% (IQR: 1.7-4.9%), p = 0.01). The DM group presented with a significantly higher presence of at least one VH IVUS-derived thin-cap fibroatheroma (VHD-TCFA) (75% vs 41%, p = 0.001) and VH IVUS-derived fibrocalcific atheroma (VHD-FCA) (75% vs 40%, p = 0.001). In the DM group, 53% of the vessels had both VHD-TCFA and VHD-FCA, which was significantly higher than non-DM group (17%, p = 0.0004).

CONCLUSIONS

Coronary plaque characteristics in DM patients showed an increased amount of dense calcium and necrotic core, as well as a higher frequency of VHD-TCFA and VHD-FCA. Atherosclerosis of the target vessel was more advanced in diabetic patients.

Phase I study of YM155, a first-in-class survivin suppressant, in patients with advanced solid tumors in Japan

3536

Background: YM155 is a small molecule expected to induce apoptosis in tumor tissue by suppressing survivin. In the US, a phase I study was conducted with a 168-hr continuous infusion every 3 wks. In Japan, we conducted a similar phase I study to evaluate toxicity profile of YM155 compared with the results of the US study. Methods: The objectives were to determine the MTD, characterize the pharmacokinetics (PK) and observe anti-tumor activity. A standard 3+3 dose escalation scheme was utilized. Results: 34 pts (M/F: 24/10, median age 60, range 26 - 81) were enrolled into 6 dose cohorts [1.8 mg/m2/day (N=3), 3.6 (6), 4.8 (6), 6.0 (8), 8.0 (6), and 10.6 (5)]. 2/5 pts experienced dose-limiting toxicities (DLT) during cycle (C) 1 at 10.6 mg/m2/day (blood creatinine increased (2), lymphocyte count decreased (1)), thus the MTD was 8.0 mg/m2/day. Both pts experienced a DLT (56 yo female, 57 yo male), reached to NCI-CTC grade 2 blood creatinine level at the end of infusion. One of them developed to grade 3 blood creatinine level on day10. They recovered to grade 1 or below in 2 wks without plasma dialysis, so that they continued YM155 infusion decreased to 8.0 mg/m2/day. Renal parameters of them changed in a regular manner, as urine microalbumin increased from day 3 to 7, protein urine from day 6 to 8, and blood creatinine from day 8 to 10. As the other DLT during C1, 1/6 pt experienced AST increased at 6.0 mg/m2/day.. The most frequent AEs were: fatigue (39%), urine microalbumin present (39%), pyrexia (33%), and anemia / haemoglobin decreased (30%). At the MTD, the median YM155 clearance was 39 L/hr with a median steady state concentration of 13 ng/mL and a median terminal half-life of 20 hours. 9/33 pts showed stable disease (SD) and minor tumor shrinkage was observed in 5 of them. One pt (thyroid carcinoma) is ongoing (40 wks) and has had disappearance of pleural effusion. Another patient (malignant fibrous histiocytoma) showed tumor regression in abdominal cavity confirmed by CT scan. Conclusions: YM155, the first survivin suppressant, was well tolerated and the MTD was 8.0 mg/m2/day x 168-hr in Japan. The contribution of YM155 to the treatment of advanced solid tumors should be evaluated in further trials.

No significant financial relationships to disclose.

Expression of tight junction associated proteins in human gastric cancer: Reduced expression of Claudin-4 correlates with tumor aggressiveness and survival

15000

Background: A tight junction is one of components of intercellular junctional complexes and play an important role in maintaining barrier function and cellular porlarity. Claudin, occluding, and ZO-1 are known as trans-membrane proteins which compose tight junction. Roles of these tight junction-associated proteins of gastric cancer is not yet determined. In this study, we investigated expression levels of these proteins in gastric cancer immunohistochemically and compared the results with clinicopathological features of the tumors and patient prognosis. Methods: One hundred and twenty-four gastric cancer patients underwent gastrectomy between 2000 and 2004 were included in this study. Formalin fixed and parafine embedded tissues were sliced into 4-μm sections and immunohistchemistry was performed using anti-claudin-4, anti-occluding and anti-ZO-1 antibodies. Stained slides were investigated and the incidence of positive cells was graded as: 0, negative; 1, < 20 %; 2, 20–80 %; 3, >80 %. Results: The expression of claudin-4, occludin, and ZO-1 was observed at the membrane, and the positivity rates in cancer tissues were 87.1%, 95.2% and 100%, respectively. In concerning with correlation between protein expression and clinicopathologic features, claudin-4 expression was significantly decreased in tumors with undifferentiated type adenocarcinoma (p<0.001), advanced T stage (p=0.0022), lymph node metastasis (p<0.001), and peritoneal metastasis (p<0.001). However, there was no significant correlation between the expression of occluding and ZO-1 and clinicopathological features. Survival time was significantly shorter in patients with reduced claudin-4 expression (p=0.0018). Cox’s multivariate analysis revealed that claudin-4 was selected as an independent prognostic factor as well as histological type and peritoneal metastasis. Conclusions: Tight junction associated proteins, especially claudin-4, appears to play an important role on tumor progression, invasion, and metastasis and correlate with poor prognosis in patients with gastric cancer.

No significant financial relationships to disclose.

Evaluation of 5-FU metabolism-relating enzyme gene expression levels using quantitative real-time RT-PCR from formalin fixed parafine embedded samples

13034

Background: We have previously reported that tumors with high orotate phosphoribosil transferase (OPRT) and low dihydropyrimidine dehydrogenase (DPD) mRNA expression levels showed remarkable sensitivity to 5-fluorouracil (5-FU) by real-time RT-PCR using fresh frozen (FF) tumor samples. However, the use of fresh frozen samples has some limitations. The use of formalin fixed parafine embedded (FFPE) samples has great advantage to apply these technologies for clinical settings. In order to investigate the feasibility of real-time RT-PCR from FFPE samples to predict sensitivitiy to 5-fluorouracil (5-FU), we investigated the gene expression levels of 5-FU metabolism-relating enzymes by real-time RT-PCR from FFPE samples and compared the results from FF samples in gastric and colorectal cancer. Methods: FFPE samples and FF samples were obtained from 46 patients with gastric cancer and 29 patients with colorectal cancer. Gene expression levels of tymidylate synthase (TS), OPRT, thymidine phosphorylase (TP) and DPD were determined by quantitative real-time RT-PCR. In FFPE samples tumor tissue was obtained using laser captured microdissection (LCM). Tumor sensitivity to 5-FU was evaluated by in vitro ATP assay. Results: Gene expression levels of TS, TP, DPD determined from FFPE samples significantly correlated with those from FF samples. Although respective gene expression levels alone failed to show signifcianct correlation with the in vitro 5-FU sensitivity, statistically significant correlation was noted either from the samples of FF or FFPE in both gastric (FF: r = 0.660, FFPE: r = 0.780) and colorectal cancer (FF: r = 0.780, FFPE: r = 0.660), when OPRT/DPD mRNA ratio was applied for comparison with the results of 5-FU sensitivity. Thus, high OPRT/DPD ratio determined from FFPE samples resulted in high sensitivity to 5-FU. Conclusions: From these results, it is suggested that sensitivity to 5-FU is predictable by quantitative RT-PCR using FFPE samples. Measurement of 5-FU metabolism-relating enzyme gene expression level from FFPE samples appeared to be feasible for predicting 5-FU sensitivity and to have great advantage to apply the molecular predicting assay in clinical settings.

[Table: see text]

Evaluation of energy state of islet independent of size using a newly developed ATP bioluminescence assay

ATP content or energy charge (EC) of islets may be a good parameter to assess viability. In this study, we examined adenine nucleotides and EC of freshly isolated or 24-hour cultured rat islets of various diameters using a novel bioluminescent enzymatic cycling assay system. For freshly isolated islets, ATP content and islet diameter showed a high correlation (r = 0.842, P < .001), but a significant correlation was not observed for cultured islets (r = 0.284) when all islets were included for the analysis. When only the cultured islets with a diameter <350 microm were included for analysis, a significant correlation was observed (r = 0.719). EC of freshly isolated islets fluctuated widely irrespective of diameter, in contrast with results of 24-hour cultured islets, which showed a stable, high EC, regardless of diameter. These data suggest that the ATP content of islets correlates with the islet size and that EC of islets widely fluctuates following isolation, indicating a significant role of monitoring ATP and EC of islets before transplantation.

Phylogeographic origin of Hokkaido house mice (Mus musculus) as indicated by genetic markers with maternal, paternal and biparental inheritance

We examined intraspecies genetic variation in house mice (Mus musculus molossinus) from the northern third of the Japanese Islands, in order to obtain evidence of the history of mouse colonization that might have shaped the current genetic diversity. We extended the previous sampling of mitochondrial cytochrome b sequence and added information from the Y-linked Sry gene and ribosomal RNA gene surveys. We distinguish mitochondrial haplotypes characteristic of the North Asian musculus subspecies group (involving M. m. musculus and M. m. molossinus) as 'MUS', and that of the Southeast Asian castaneus subspecies group as 'CAS' (although the mice resemble MUS morphologically). There was a clear geographic partition of MUS and CAS types into southern and northern Hokkaido, respectively. Conversely, on Tohoku, the MUS and CAS types were interspersed without clear geographic subdivision. In contrast to the mtDNA data, all Hokkaido and Tohoku mice examined were found to possess a unique type for the Y-linked Sry gene, specific to Korea and Japan. Restriction site analysis of nuclear rDNA probe showed a consistent distribution of MUS and CAS types, as major and minor components, respectively, in the Hokkaido and Tohoku mice. These data support the previous notion that the Hokkaido and Tohoku mice experienced genetic hybridization between primary residents of CAS origin and MUS newcomers arriving via a southern route. The invasion of the MUS type could correspond with the evidence for arrival of prehistoric peoples. There are, however, alternative interpretations, including genetic admixture between MUS arriving by a southern route and CAS from a northern route.

RASSF2, a potential tumour suppressor, is silenced by CpG island hypermethylation in gastric cancer

RASSF2, a member of the RASSF1 family, has recently been identified as a potential tumour suppressor. We examined methylation status in multiple regions which included the CpG island and spanned the transcription start site of RASSF2 in 10 gastric cancer cell lines, as well as 78 primary gastric cancers and corresponding non-neoplastic gastric epithelia. Hypermethylation of RASSF2 in at least one of the regions examined was detected in seven (70%) of the 10 cell lines; two (20%) exhibited hypermethylation in all the regions examined including the transcription start site and lost expression of RASSF2 mRNA, which could, however, be restored by 5-aza-2′ deoxycytidine treatment, while the other five (50%) cell lines exhibited hypermethylation at the 5′- and/or 3′- edge, with four of them expressing RASSF2 mRNA. In primary gastric cancers and corresponding non-neoplastic gastric epithelia, frequencies of RASSF2 methylation ranged from 29% (23 out of 78) to 79% (62 out of 78) and 3% (two out of 78) to 60% (47 out of 78), respectively, at different CpG sites examined. Methylation was frequently observed at the 5′- and 3′- edges, and became less frequent near the transcription start site in both the primary gastric cancers and corresponding non-neoplastic gastric epithelia. Hypermethylation near the transcription start site was mostly cancer-specific. We thus showed that RASSF2 is silenced by hypermethylation near the transcription start site in gastric cancer. Hypermethylation was found initially to occur at the 5′- and 3′- furthest regions of the CpG island in non-neoplastic gastric epithelia, to gradually spreads near the transcription start site to shut down RASSF2 expression, and ultimately to constitute a field-defect placing tissue increased risk for development of gastric cancer.

Gene expression profiles in human gastric cancer: expression of maspin correlates with lymph node metastasis

To seek for a candidate gene that would regulate tumour progression and metastasis in gastric cancer, we investigated gene expression profiles by using DNA microarray. Tumour tissue and adjacent normal tissue were obtained from 21 patients with gastric cancer and then examined for their gene expression profiles by the Gene Chip Human U95Av2 array, which includes 12 000 human genes and EST sequences. A total of 25 genes were upregulated and two genes were downregulated by at least four-fold in the tumour tissue. In a further analysis according to lymph node metastasis, the expressed levels of maspin, as well as carcinoembryonic antigen and nonspecific crossreacting antigen were significantly higher in tumours with lymph node metastasis than in those without it. Maspin expression in 85 gastric cancer patients was further investigated by using immunohistochemistry. Maspin expression was not observed in normal gastric epithelia without intestinal metaplasia. In contrast, maspin was expressed in 74 of 85 tumour tissues. There was a significant correlation between the incidence of maspin-positive tumour staining and lymph node metastasis. These results suggest that maspin has a potential role for tumour metastasis in gastric cancer.

A novel method for determination of ATP, ADP, and AMP contents of a single pancreatic islet before transplantation

Assessment of islet viability before transplantation is mandatory for successful clinical transplantation. ATP content or energy charge (EC) of islets may represent a good parameter to assess viability. We have introduced a novel bioluminescent enzymatic cycling assay using synthetic firefly luciferase, pyruvate kinase) (PK), and pyruvate orthophosphate dikinase (PPDK) to determine adenine nucleotides (AN) in isolated islets. A complete assay requires several minutes. The ATP contents of 1, 3, 10, 30 or 100 islets each with a diameter of 150 microm were 9.95 +/- 0.03, 28.3 +/- 1.18, 89.5 +/- 1.48, 282 +/- 10.2, and 673 +/- 27.1 pmol, respectively, showing a relatively constant ATP content per 30 islets (9.95, 9.42, 8.95, and 9.41 pmol/IEQ). ECs of each group were 0.74 +/- 0.02, 0.74 +/- 0.02, 0.75 +/- 0.02, 0.74 +/- 0.02, and 0.65 +/- 0.01, respectively, a value that was quite constant up to 30 islets. The quantity of ATP and EC in a single islet can be measured quickly and reproducibly, offering a new method to determine viability of isolated islets prior to transplantation.

Prognostic significance of peritoneal minimal residual disease in gastric cancer detected by reverse transcription-polymerase chain reaction

BACKGROUND

A sensitive method for detecting minimal residual disease in the peritoneal cavity by quantifying carcinoembryonic antigen (CEA) mRNA using real-time quantitative reverse transcription-polymerase chain reaction (RQ-RT-PCR) was developed. The clinical value of the method for predicting peritoneal recurrence in patients with gastric cancer was evaluated.

METHOD

A total of 195 patients with gastric cancer and 20 with asymptomatic cholecystolithiasis were included in the study. CEA mRNA expression in peritoneal washings (p-CEA mRNA) was measured by RQ-RT-PCR and normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA expression. The cut-off level of p-CEA mRNA for gastric cancer was determined by examining p-CEA mRNA levels in patients with asymptomatic cholecystolithiasis.

RESULTS

Fifty-five (28.2 per cent) of the 195 patients were p-CEA mRNA positive. The rate of p-CEA mRNA positivity correlated significantly with clinicopathological factors. In 163 patients who underwent curative surgery, overall survival and disease-free survival were significantly poorer in p-CEA mRNA-positive patients than in p-CEA mRNA-negative patients (P < 0.001). Cox regression analysis revealed that only p-CEA mRNA was a significant independent prognostic factor (P = 0.034). Multivariate logistic regression analysis showed that p-CEA mRNA was a significant independent risk factor for peritoneal recurrence (P = 0.027).

CONCLUSION

These results suggest that p-CEA mRNA is a reliable prognostic factor and predictor of peritoneal recurrence in gastric cancer.

Demethylation of MAGE promoters during gastric cancer progression

Melanoma antigen (MAGE)-encoding genes are expressed in various tumour types via demethylation of their promoter CpG islands, which are silent in all non-neoplastic tissues except for the testis and placenta. The clinicopathological significance of demethylation of MAGE genes in gastric carcinoma is not known. We investigated the promoter methylation status of MAGE-A1 and -A3 in 10 gastric cancer cell lines and in surgical specimens from 84 gastric cancer patients by methylation-specific PCR (MSP). Expression of MAGE-A1 and -A3 in the 10 gastric cancer cell lines was also investigated by RT–PCR. Any correlation between the methylation status of the MAGE promoters and clinicopathological characteristics of the gastric cancer patients was then assessed. Eight of the 10 gastric cancer cell lines showed demethylation of both MAGE-A1 and -A3, and the remaining two cell lines did either of MAGE-A1 or -A3. Expression of MAGE-A1 and -A3 was confirmed in seven and nine of the 10 gastric cancer cell lines, respectively. The MAGE-A1 and -A3 promoters were demethylated in 29% (25 out of 84) and 66% (56 out of 84) of the gastric tumour specimens, respectively. Demethylation of both MAGE-A1 and -A3 promoters (n=22) was found more frequently in gastric cancer patients in advanced clinical stages (P=0.0035), and these patients also exhibited a higher incidence of lymph node metastasis (P=0.0007) compared to those patients without demethylation (n=25). Furthermore, demethylation patients tended to have a worse prognosis, although this difference was not statistically significant (P=0.183). Demethylation of MAGE-A1 and -A3 occurs during progressive stages of gastric cancer, and may be associated with aggressive biological behaviour of gastric cancer.

Superior antitumour activity of S-1 in tumours with a high dihydropyrimidine dehydrogenase activity

To elucidate the mechanism of the enhanced antitumour activity of S-1 (1 M tegafur, 0.4 M 5-chloro-2, 4-dihydroxypyridine, and 1 M potassium oxonate) in terms of the phosphorylation and degradation pathways of 5-fluorouracil (5-FU) metabolism, we investigated tumoral thymidylate synthase (TS) content, dihydropyrimidine dehydrogenase (DPD) activity, the TS inhibition rate (TS-IR), and 5-FU incorporated into RNA (F-RNA) in four human gastric cancer xenografts (MKN-28, MKN-74, GCIY and GT3TKB) and compared the results obtained with S-1 with those obtained with 5-FU and UFT (1 M tegafur, 4 M uracil). 5-FU was administered intraperitoneally (i.p.) to mice at a dose of 50 mg/kg, three times, on days 0, 4 and 8. S-1 and UFT were administered orally at doses of 10 and 24 mg/kg, respectively, once a day, for 9 consecutive days. Antitumour activity was evaluated as the maximum inhibition of tumour growth in each animal. S-1 showed a better antitumour activity than 5-FU and UFT in tumours with a high DPD activity (GCIY and GT3TKB). There were inverse correlations between the antitumour activity and both TS content and DPD activity in the 5-FU and UFT groups. However, no such correlations were observed in the S-1 group. In GCIY and GT3TKB xenografts, TS-IR was significantly higher in the S-1 group than in the 5-FU or UFT groups. In GT3TKB xenografts, the F-RNA level was significantly higher in the S-1 group than in the 5-FU or UFT groups. The superior cytotoxicity of S-1 appears to be attributable to both an increased inhibition of DNA synthesis and an enhanced blockade of RNA function against tumours with a high DPD activity.