Jmjd5, an H3K36me2 histone demethylase, modulates embryonic cell proliferation through the regulation of Cdkn1a expression

Covalent modifications of histones play an important role in chromatin architecture and dynamics. In particular, histone lysine methylation is important for transcriptional control during diverse biological processes. The nuclear protein Jmjd5 (also called Kdm8) is a histone lysine demethylase that contains a JmjC domain in the C-terminal region. In this study, we have generated Jmjd5-deficient mice (Jmjd5(Δ)(/)(Δ)) to investigate the in vivo function of Jmjd5. Jmjd5(Δ)(/)(Δ) embryos showed severe growth retardation, resulting in embryonic lethality at the mid-gestation stage. Mouse embryonic fibroblasts (MEFs) derived from Jmjd5 hypomorphic embryos (Jmjd5(neo/neo)) also showed the growth defect. Quantitative PCR analysis of various cell cycle regulators indicated that only Cdkn1a expression was upregulated in Jmjd5(neo/neo) MEFs and Jmjd5(Δ)(/)(Δ) embryos. A knockdown assay with Cdkn1a-specific small interfering RNAs revealed that the growth defect of Jmjd5(neo/neo) MEFs was significantly rescued. In addition, a genetic study using Jmjd5(Δ)(/)(Δ); Cdkn1a(Δ)(/)(Δ) double-knockout mice showed that the growth retardation of Jmjd5(Δ)(/)(Δ) embryos was partially rescued by Cdkn1a deficiency. Chromatin immunoprecipitation analysis showed that increased di-methylated lysine 36 of histone H3 (H3K36me2) and reduced recruitment of endogenous Jmjd5 were detected in the transcribed regions of Cdkn1a in Jmjd5(neo/neo) MEFs. Taken together, these results suggest that Jmjd5 physiologically moderates embryonic cell proliferation through the epigenetic control of Cdkn1a expression.

Efficacy of adjuvant chemotherapy with S-1 in patients with positive peritoneal cytology (CY1) who underwent R1 surgery

84

Background: In recent TNM classification, positive peritoneal cytology (CY1) is regarded as M1 disease and classified into stage IV. However, the prognosis of the CY1 patients underwent R1 surgery (microscopic residual tumor) is considered to be relatively better than those underwent R2 surgery (macroscopic residual tumor). Adjuvant chemotherapy with S-1 had demonstrated significant survival benefit in stage II and III gastric cancer in Japan. However, the efficacy of adjuvant S-1 in patients with relatively more advanced stage had not been investigated. Therefore, we investigated the efficacy of adjuvant chemotherapy with S-1 in CY1 patients underwent R1 surgery.

Methods: Among the 2,202 patients with gastric cancer treated at our department between September 2002 and July 2009, a total of 105 patients with CY1 and underwent R1 surgery were included in this study. Clinocopathological features and survival were retrospectively analyzed using prospectively registered data base system.

Results: There were 64 male and 41 female patients. The median age was 61 years old. Eighty-five patients had T4a or T4b tumor and 96 patients had lymph node metastasis. Seventy-eight patients had undifferentiated type of tumor. In 83 patients, adjuvant chemotherapy with S-1 had been performed. In the uni-variate analysis, only the extent of lymph node dissection (D2) and the adjuvant chemotherapy with S-1 demonstrated significant survival benefit. In multi-variable analysis using Cox proportional hazarded model, N-factor, extent of lymph node dissection (D2 vs D1), and adjuvant chemotherapy with S-1 were selected as independent prognostic factors. The median survival time and 5-year survival rate in patients underwent R1 resection with D2 lymphadenectomy and adjuvant S-1 treatment were 42 months and 46%, respectively.

Conclusions: In patients with CY1 and underwent R1 surgery, adjuvant chemotherapy with S-1 demonstrated significant survival benefit. In patients with positive peritoneal cytology without other non-curative factors, D2 lymph node dissection and adjuvant chemotherapy using S-1 is recommended.

No significant financial relationships to disclose.

Prognostic value of duodenal invasion length in patients with gastric cancer

24

Background: Duodenal invasion (DI) has been considered as a poor prognostic factor of gastric cancer patients. Not all the patients would be able to undergo curative operation. Neoadjuvant chemotherapy (NAC) may improve the rate of curative operation of these patients. In this study, we investigated whether the length of duodenal invasion preoperative diagnosis can be one of factor to decide indication of NAC.

Methods: A total of 118 gastric cancer patients with clinically evident DI, who underwent laparotomy at our center, were enrolled in this study. 42 patients with DI length 20 mm or longer were categorized into long invasion group (LI), 76 patients with DI length shorter than 20 mm were categorized into short invasion group (SI). Clinicopathologic features, rate of direct invasion and lymph nodes involvement, R0 resection, and survival rate were compared between two groups.

Results: Resection rate was significantly different between two groups: SI group (85.5%; 65/76), LI group (69.0%; 29/42). Direct invasion to adjacent organs was significantly more frequently observed in LI group (21%; 6/29) than SI group (4 %; 3/65, p = 0.02). In LI group, pancreas invasion was observed in all patients except for one patient. Multivariate analysis to predict the adjacent organ invasion revealed that CT diagnosis (p = 0.005) and invasion length (p = 0.01) were selected as risk factors of direct invasion to adjacent organs. There was no significant difference of nodal involvement between LI group (83%; 24/29) and SI group (83%; 54/65 p = 0.99). The 5-year survival rate was 19% in LI group and 43% in SI group (p = 0.23). The number of patients who underwent R0 resection was more frequently in SI group (75.4%; 49/65) than SI group (69.1%; 16/29). The factors of R1 or R2 resection were metastasis of peritoneum or direct invasion to adjacent organs.

Conclusions: In patients with long duodenal invasion, direct invasion to the pancreas was more frequently observed, and resulted in low curative resection rate and poor survival. Preoperative chemotherapy may improve the curative resection rate and survival in these patients. Prospective study is warranted to evaluate the efficacy of NAC for these patients.

No significant financial relationships to disclose.

Sorption and diffusion of Eu in sedimentary rock in the presence of humic substance

Sorption and diffusion behaviors of Eu in sedimentary rock in the presence of humic substance were investigated. The sedimentary rock collected from 500 m depth of HDB-6 bore hole at horonobe URL site of Japan and Aldrich humic acid (HA) were used in the present study. Sorption behaviors of Eu and the HA on the sedimentary rocks with and without the rock organic matter (ROM) were elucidated as a function of HA concentration. The HA reduced the sorption of Eu on the rock with the increase of HA. Eu and HA sorption on the rock with the ROM was larger than on the rock after removing the ROM, indicating that the ROM plays an important role on the sorption of Eu and HA. The diffusion of Eu in the presence of HA was examined as a function of HA concentration and molecular weight of the HA (∼150 kDa or below 10 kDa) by means of a reservoir depletion test method with the intact rock core of the sedimentary rock. Depletion of Eu concentration in the reservoir was reduced with the increase of HA concentration. On the other hand, slight depletion of HA concentration in the reservoir was observed, indicating that the larger HA molecule diffused less into the rock. From the depletion curve and in-diffusion profile of Eu in the rock, the effective diffusion coefficient, D e, and distribution coefficient, K d, in the intact system were estimated based on the profile fitting of the diffusion data with the conventional simple diffusion-sorption model. It was elucidated that the HA reduced the K d and D e of Eu in the intact system with the increase of HA. The contribution of the HA with smaller molecular weight to both the Eu sorption and diffusion was examined.

Feasibility study of adjuvant chemotherapy with S-1 plus cisplatin for gastric cancer

PURPOSE

To evaluate the feasibility of S-1 plus cisplatin as adjuvant chemotherapy for stage III gastric cancer after curative resection.

METHODS

Japanese patients with stage III gastric cancer who underwent gastrectomy with D2 lymph node resection were enrolled. Treatment consisted of 3 cycles of S-1 (80 mg/m(2)/day, b.i.d.) for 21 days followed by a 14-day rest, and cisplatin (60 mg/m(2) iv) on day 8. After that, S-1 monotherapy was given on days 1-28 every 6 weeks until 1-year postsurgery. After protocol amendment, the first chemotherapy cycle consisted of S-1 monotherapy; cisplatin was added to cycles 2, 3, and 4, followed by S-1 monotherapy up to 1-year postsurgery. The primary endpoint was the completion rate of three cycles of S-1 plus cisplatin.

RESULTS

A total of 63 enrolled patients have been evaluated. Grade 3/4 toxicities included neutropenia (40%), anorexia (28%), and febrile neutropenia (4%) before protocol amendment (n = 25), and neutropenia (37%), anorexia (8%), and febrile neutropenia (3%) after amendment implementation (n = 38). Excluding ineligible cases, treatment completion rates were 57% (12/21) before and 81% (30/37) after the protocol amendment.

CONCLUSIONS

The amended S-1 plus cisplatin is more feasible than the original protocol because of early dose reduction of S-1 prior to cisplatin addition and greater recovery time from surgery prior to cisplatin. This treatment should be considered as a feasible experimental arm for the next postoperative adjuvant phase III trial.

The tumor suppressor Rb and its related Rbl2 genes are regulated by Utx histone demethylase

Utx is a candidate tumor suppressor gene that encodes histone H3 lysine 27 (H3K27) demethylase. In this study, we found that ectopic expression of Utx enhanced the expression of retinoblastoma tumor suppressor gene Rb and its related gene Rbl2. This activation was dependent on the demethylase activity of Utx, and was suggested to contribute to the decreased cell proliferation induced by Utx. A chromatin immunoprecipitation assay showed that over-expressed Utx was associated with the promoter regions of Rb and Rbl2 resulting in the removal of repressive H3K27 tri-methylation and the increase in active H3K4 tri-methylation. Furthermore, siRNA-mediated knockdown of Utx revealed the recruitment of endogenous Utx protein on the promoters of Rb and Rbl2 genes. These results indicate that Rb and Rbl2 are downstream target genes of Utx and may play important roles in Utx-mediated cell growth control.

Jmjd2c histone demethylase enhances the expression of Mdm2 oncogene

Jmjd2c is a candidate oncogene that encodes histone lysine demethylase. In this study, we discovered that over-expression of Jmjd2c increased the expression of Mdm2 oncogene dependent on its demethylase activity, which led to the reduction of p53 tumor suppressor gene product in the cells. A chromatin immunoprecipitation assay showed that Jmjd2c was recruited to the P2 promoter region of Mdm2 gene resulting in demethylation of histone H3 lysine 9, as typically found in actively transcribed genes. Furthermore, siRNA-mediated knockdown of Jmjd2c caused the reduction of Mdm2 expression in the cells. These results indicate that Mdm2 oncogene is a downstream target of Jmjd2c and may play an important role in Jmjd2c-mediated oncogenesis.

Phase I clinical and biomarker study of BIBF 1120, an oral multitarget tyrosine kinase inhibitor, in patients with advanced solid tumors (ST): Impact of CD133- and CD117-positive cells on a biomarker of an antiangiogenic inhibitor

3572

Background: BIBF 1120 (Vargatef) is an orally bioavailable small molecule inhibitor of multiple receptor tyrosine kinases, including vascular endothelial growth factor receptors, fibroblast growth factor receptors and platelet-derived growth factor receptors. Methods: BIBF 1120 (150–250 mg) was administered orally twice-daily (bid) to heavily pre-treated solid tumor (ST) patients to determine safety, tolerability, maximum tolerated dose (MTD) and pharmacokinetics (PK). CD133- and/or CD117 (c-kit)-positive cells from CD34+CD45dim peripheral blood cells were evaluated using flow-cytometry on pre-treatment, Day 2, Day 8 and Day 29. Results: Twenty-one patients were treated at doses of 150 mg bid (n=3), 200 mg bid (n=12) and 250 mg bid (n=6). Dose-limiting toxicities (DLTs) of reversible Grade 3/4 elevated liver enzymes occurred in three of 12 patients at 200 mg bid and three of six patients at 250 mg bid; 200 mg bid was declared as the MTD. Best observed responses were stable disease in 16 (76.2%) patients and median progression-free survival was 113 days (95% CI: 77–119 days). PK analysis indicated that Cmax and AUC increased with increased dose within the dose range tested. Flow cytometry analysis revealed that BIBF 1120 treatment significantly increased the percentage of CD133+CD117- cells (p<0.001) on Day 29 compared with pre-treatment, and conversely decreased that of CD133-CD117+ cells (p<0.01). In addition, CD133+CD117+ cells tended to decrease in responders (stable disease) to a greater extent than in non- responders after treatment. Conclusions: BIBF 1120 dosed continuously at 200 mg bid was well tolerated and appeared to provide some clinical benefit. Our biomarker study provides a novel insight into CD133- and CD117-positive cells as a pharmacodynamic biomarker for an antiangiogenic inhibitor.

[Table: see text]

Phase I study of sunitinib (SU) in combination with pemetrexed (Pem) in patients (pts) with advanced solid tumors (ST)

e14630

Background: SU is an oral, multitargeted tyrosine kinase inhibitor of VEGFRs, PDGFRs, KIT, RET, FLT3, and CSR-1, and shows antitumor activities in several types of solid malignancies. Non-small-cell lung cancer (NSCLC) xenograft data indicate SU enhanced the antitumor activity of Pem. This phase I study was designed to evaluate the safety, tolerability, and pharmacokinetics (PK) of combination therapy with the oral SU and Pem for Japanese patients with advanced ST. Methods: Pts with ST refractory to standard therapy were randomly assigned to receive either oral SU 50 mg/day for 2 weeks followed by 1 week rest (Schedule 2/1, S-2/1) or SU 37.5 mg continuous daily dose (CDD). Fixed-dose Pem (500mg/m2 IV) was administered on day1 every 21 days. A standard “3+3” design was employed in both treatment schedules and treatment continued until tumor progression or dose-limiting toxicity (DLT) was observed. Results: A total of 12 pts (med. age 63 years, range 49–69; 10 Male/ 2 Female) have been enrolled (6 pts in the S-2/1 arm and 6 pts in the CDD arm). The most common cancer is NSCLC (9 pts, 75%). All patients completed their first cycle for DLT evaluation, and no DLTs were observed in either treatment arm. The most common toxicities were fatigue (n=8), anorexia (n=6), and thrombocytopenia (n=12). Treatment-related ≥ grade 3 adverse events (AEs) included fatigue (n=1), hypertension (n=1), neutropenia (n=4), leucopenia (n=3), thrombocytopenia (n=2), lymphopenia (n=2), and increased ALT (n=1). Three pts (S-2/1: 2, CDD: 1) required dose reduction of SU due to G3 toxicities. All toxicities were clinically manageable and reversible. One pt with NSCLC had a documented PR with cavity formation inside the tumor. Conclusions: SU 37.5 mg/day (CDD schedule) plus Pem 500mg/m2 every 21 days, and SU 50 mg/day (S-2/1 schedule) plus Pem 500mg/m2 every 21 days were well tolerated and associated with encouraging antitumor activity.

[Table: see text]

Prospective multicenter trial of sentinel node mapping for gastric cancer

4518

Background: The sentinel node (SN) concept has revolutionized the approach to the surgical staging of both melanoma and breast cancer, and these techniques can yield patient benefit by avoiding various complications due to unnecessary prophylactic regional lymph node dissection in cases with negative SN for cancer metastasis. Clinical application of SN mapping for early gastric cancer had been controversial for years. However, single institutional results of SN mapping for early gastric cancer are almost acceptable results in terms of detection rate and accuracy to determine lymph node status. We hypothesized that SN mapping plays a key role to obtain individual information and allows modification of the surgical procedure for early gastric cancer. Methods: The Japan Society of Sentinel Node Navigation Surgery (JSNNS) has conducted a prospective multicenter trial of SN mapping by a dual tracer method with radioactive colloid and blue dye. Between September 2004 and March 2008, 433 patients with early gastric cancer were accrued at 12 comprehensive hospitals. Patients were enrolled under JSNNS and each institutional review board-approved protocols. Eligibility criteria were that patients had clinically T1N0M0 or T2N0M0 single tumor with diameter of primary lesion less than 4cm without any previous treatments. Technetium-99m tin colloid and isosulfan blue were utilized as dual tracers for SN mapping. Results: SN mapping has been performed for 397 patients with early gastric cancer. Detection rate of hot and/or blue node using our procedure was 97.5% (387/397). The mean number of sentinel nodes per case was 5.6. Fifty-three of 57 cases with lymph node metastasis showed positive sentinel nodes. The sensitivity to detect metastasis based on SN status was therefore 93% in our experience. Accuracy of metastatic status based on SN was 99% (383/387). In two of the four SN false-negative cases, the tumor involved to pT2, and only one case showed the metastatic lymph node beyond the SN basin. Conclusions: Our results suggest that SN concept for clinically N0 early gastric cancer could be validated, and minimized gastrectomy with individualized selective and modified lymphadenectomy for early gastric cancer with negative SN should become feasible and clinically useful as less invasive surgical procedures.

No significant financial relationships to disclose.

Chemokine-like factor expression in the idiopathic inflammatory myopathies

OBJECTIVES

We evaluated the expression of chemokine-like factor (CKLF) in biopsied muscle fibers in inflammatory myopathies, non-inflammatory myopathies and neurologically diseased controls.

MATERIALS AND METHODS

We studied the expression of CKLF in 15 polymyositis (PM), five dermatomyositis (DM), 15 non-inflammatory myopathies and nine neurologically diseased patients by immunohistochemistry.

RESULTS

Chemokine-like factor was mostly expressed in small diameter muscle fibers surrounded by infiltrated lymphocytes of inflammatory myopathies patients. Parts of them were also positive for the staining of the developmental form of myosin heavy chain, a maker of regenerating muscle fibers. Thrombin immunoreactivity was observed in endomysium in PM and perimysium in DM. In vitro differentiation study showed a constitutive expression of CKLF in myoblasts that was abolished in myotubes during differentiation process and was induced again by thrombin. Thrombin regulates CKLF expression through protease-activated receptor-1 in myotubes. Treatment of a protein kinase C inhibitor partially blocked CKLF expression in myoblasts, while it remarkably inhibited that in myotubes.

CONCLUSION

Chemokine-like factor expression is differentially regulated in myoblasts and myotubes. Thrombin could be a strong regulator for its expression. As CKLF is immunohistochemically positive in regenerating muscle fibers, we postulate here that CKLF is a useful marker for regenerating muscle fibers in inflammatory myopathies.

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]