[A Case of Abdominal Fullness Caused by a Retroperitoneal Bulky Tumor Treated with Epidural Analgesia].

We presented the case of a 63-year-old woman with severe abdominal distention due to recurrent retroperitoneal sarcoma. Further, the rapid progression of the tumor made it difficult to relieve the abdominal distention. Titrated intravenous morphine was administered. Although the dose of morphine was escalated and the patient was sedated, she continued to experience pain. The addition of a continuous epidural analgesic lidocaine to manage the abdominal distention was effective. This case report describes a stepwise approach with continuous epidural analgesia of lidocaine for a bulky tumor- related abdominal distention.

KRAS mutation analysis of single circulating tumor cells from patients with metastatic colorectal cancer.

BACKGROUND: The molecular profiles of tumors may inform the selection of appropriate targeted therapies. Circulating tumor cells (CTCs) reflect the real-time status of tumor genotypes. CTCs exhibit high genetic heterogeneity within a patient; accordingly, the analysis of individual CTCs, including their heterogeneity, may enable more precise treatments. We analyzed KRAS mutations in single CTCs from patients with metastatic colorectal cancer (mCRC) using a new single-cell picking system. METHODS: Blood samples were obtained from 61 patients with mCRC. CTCs were enriched and fluorescently labeled using the CellSearch® System. They were recovered using the single-cell picking system based on the fluorescence intensity of marker dyes. Single CTCs and tumor tissue samples were examined for mutations in codons 12 and 13 of the KRAS gene. RESULTS: CTCs were detected in 27 of 61 patients with mCRC. We isolated at least two CTCs from 15 of 27 patients. KRAS genotype was evaluated in a total of 284 CTCs from 11 patients, and 15 cells with mutations were identified in four patients. In 10 of 11 patients, the KRAS status was the same in the primary tumor and CTCs. In one patient, the KRAS status was discordant between the primary tumor and CTCs. In two patients, different KRAS mutations were found among individual CTCs. CONCLUSIONS: We successfully isolated single CTCs and detected KRAS mutations in individual cells from clinical samples using a novel application of single-cell isolation system. Using the system, we detected CTC heterozygosity and heterogeneity in KRAS status among CTCs within a patient and between CTCs and tumor tissues.

Glycogen synthase kinase 3ß inhibition sensitizes human glioblastoma cells to temozolomide by affecting O6-methylguanine DNA methyltransferase promoter methylation via c-Myc signaling.

Glycogen synthase kinase 3ß (GSK3ß) is a serine/threonine protein kinase involved in human cancers including glioblastoma. We have previously demonstrated that GSK3ß inhibition enhances temozolomide effect in glioma cells. In this report, we investigated the molecular mechanisms of sensitization of glioblastoma cells to temozolomide by GSK3ß inhibition, focusing on O(6)-methylguanine DNA methyltransferase (MGMT) gene silencing. Glioblastoma tissues from patients treated with the GSK3ß-inhibiting drugs were subjected to immunohistochemistry and methylation-specific PCR assay. Human glioblastoma cell lines T98G, U138, U251 and U87 were treated with a small-molecule GSK3ß inhibitor, AR-A014418 or GSK3ß-specific small interfering RNA. The combined effect of temozolomide and AR-A014418 on cell proliferation was determined by AlamarBlue assay and an isobologram method. MGMT promoter methylation was estimated by methylation-specific PCR and MethyLight assay. MGMT gene expression was evaluated by real-time quantitative reverse transcriptase-PCR. c-Myc and DNA (cytosine-5)-methyltransferase 3A binding to the MGMT promoter was estimated by chromatin immunoprecipitation assay. GSK3ß inhibition decreased phosphorylation of glycogen synthase and reduced MGMT expression and increased MGMT promoter methylation in clinical tumors. In glioblastoma cell lines, GSK3ß inhibition decreased cell viability, enhanced temozolomide effect and downregulated MGMT expression with relevant changes in the methylation levels of the MGMT promoter. Here, we showed for the first time that c-Myc binds to the MGMT promoter with consequent recruitment of DNA (cytosine-5)-methyltransferase 3A, regulating the levels of MGMT promoter methylation. The results of this study suggest that GSK3ß inhibition enhances temozolomide effect by silencing MGMT expression via c-Myc-mediated promoter methylation.

AP1B plays an important role in intestinal tumorigenesis with the truncating mutation of an APC gene.

Recent evidence has suggested that carcinoma is accompanied by the loss of cell polarity. An epithelial cell-specific form of the AP-1 clathrin adaptor complex, AP1B, is involved in the polarized transport of membrane proteins to the basolateral surface of epithelial cells. In our study, we investigated whether AP1B is involved in intestinal tumorigenesis. The cellular polarity of intestinal tumor cells was examined using APC(Min/+) mice as an in vivo model and SW480 cells with a truncating mutation in the adenomatous polyposis coli (APC) gene as an in vitro model by confocal microscopy. Next, the expression of AP1B in intestinal tumor cells was examined by real-time polymerase chain reaction (PCR) and Western blotting. The localization of ß-catenin and the expression of AP1B in the tumor tissue of patients with colorectal cancer were evaluated by confocal microscopy and real-time PCR, respectively, and the relationships among cell polarity, AP1B expression and intestinal tumorigenesis were examined. Cellular polarity was lost in intestinal tumor cells, and the expression of AP1B was downregulated. In addition, the reduction in the expression level of AP1B correlated with the nuclear localization of ß-catenin in human colorectal cancer. Our study indicates the close associations between AP1B, intestinal tumorigenesis and mutations in the APC gene. This is the first report to reveal the relationships among AP1B, cellular polarity and intestinal tumorigenesis, and achieving a detailed understanding of AP1B will hopefully lead to discovery of therapeutic targets and novel biomarkers for intestinal cancer.

Inhibition of gastric carcinogenesis by the hormone gastrin is mediated by suppression of TFF1 epigenetic silencing.

BACKGROUND & AIMS: Epigenetic alterations have been correlated with field cancerization in human patients, but evidence from experimental models that specific epigenetic changes can initiate cancer has been lacking. Although hormones have been associated with cancer risk, the mechanisms have not been determined. The peptide hormone gastrin exerts a suppressive effect on antral gastric carcinogenesis. METHODS: N-methyl-N-nitrosourea (MNU)-dependent gastric cancer was investigated in hypergastrinemic (INS-GAS), gastrin-deficient (GAS(-/-)), Tff1-deficient (Tff1(+/-)), and wild-type (WT) mice. Epigenetic alterations of the trefoil factor 1 (TFF1) tumor suppressor gene were evaluated in vitro and in vivo. RESULTS: Human intestinal-type gastric cancers in the antrum exhibited progressive TFF1 repression and promoter hypermethylation. Mice treated with MNU exhibited a field defect characterized by widespread Tff1 repression associated with histone H3 lysine 9 methylation and H3 deacetylation at the Tff1 promoter in epithelial cells. In MNU-induced advanced cancers, DNA methylation at the Tff1 promoter was observed. Tumor induction and Tff1 repression were increased in MNU-treated mice by Helicobacter infection. Hypergastrinemia suppressed MNU-dependent tumor initiation and progression in a manner that correlated with gene silencing and epigenetic alterations of Tff1. In contrast, homozygous gastrin-deficient and heterozygous Tff1-deficient mice showed enhanced MNU-dependent field defects and cancer initiation compared with WT mice. In gastric cancer cells, gastrin stimulation partially reversed the epigenetic silencing in the TFF1 promoter. CONCLUSIONS: Initiation of antral gastric cancer is associated with progressive epigenetic silencing of TFF1, which can be suppressed by the hormone gastrin.

LINE-1 methylation shows little intra-patient heterogeneity in primary and synchronous metastatic colorectal cancer.

BACKGROUND: Long interspersed nucleotide element 1 (LINE-1) hypomethylation is suggested to play a role in the progression of colorectal cancer (CRC). To assess intra-patient heterogeneity of LINE-1 methylation in CRC and to understand its biological relevance in invasion and metastasis, we evaluated the LINE-1 methylation at multiple tumor sites. In addition, the influence of stromal cell content on the measurement of LINE-1 methylation in tumor tissue was analyzed. METHODS: Formalin-fixed paraffin-embedded primary tumor tissue was obtained from 48 CRC patients. Matched adjacent normal colon tissue, lymph node metastases and distant metastases were obtained from 12, 18 and 7 of these patients, respectively. Three different areas were microdissected from each primary tumor and included the tumor center and invasive front. Normal mucosal and stromal cells were also microdissected for comparison with the tumor cells. The microdissected samples were compared in LINE-1 methylation level measured by multicolor MethyLight assay. The assay results were also compared between microdissected and macrodissected tissue samples. RESULTS: LINE-1 methylation within primary tumors showed no significant intra-tumoral heterogeneity, with the tumor center and invasive front showing identical methylation levels. Moreover, no difference in LINE-1 methylation was observed between the primary tumor and lymph node and distant metastases from the same patient. Tumor cells showed significantly less LINE-1 methylation compared to adjacent stromal and normal mucosal epithelial cells. Consequently, LINE-1 methylation was significantly lower in microdissected samples compared to macrodissected samples. A trend for less LINE-1 methylation was also observed in more advanced stages of CRC. CONCLUSIONS: LINE-1 methylation shows little intra-patient tumor heterogeneity, indicating the suitability of its use for molecular diagnosis in CRC. The methylation is relatively stable during CRC progression, leading us to propose a new concept for the association between LINE-1 methylation and disease stage.

Long interspersed nuclear element-1 hypomethylation is a potential biomarker for the prediction of response to oral fluoropyrimidines in microsatellite stable and CpG island methylator phenotype-negative colorectal cancer.

We investigated the clinical value of methylation of long interspersed nuclear element-1 (LINE-1) for the prognosis of colorectal cancer (CRC) and for the survival benefit from adjuvant chemotherapy with oral fluoropyrimidines. LINE-1 methylation in tumor DNA was measured by quantitative methylation-specific PCR in 155 samples of stage II and stage III CRC. The presence of microsatellite instability and CpG island methylator phenotype (CIMP) were assessed and 131 microsatellite stable/CIMP- cases were selected for survival analysis, of which 77 patients had received postoperative adjuvant chemotherapy with oral fluoropyrimidines. The CRC cell lines were used to investigate possible mechanistic links between LINE-1 methylation and effects of 5-fluorouracil (5-FU). High LINE-1 methylation was a marker for better prognosis in patients treated by surgery alone. Patients with low LINE-1 methylation who were treated with adjuvant chemotherapy survived longer than those treated by surgery alone, suggestive of a survival benefit from the use of oral fluoropyrimidines. In contrast, a survival benefit from chemotherapy was not observed for patients with high LINE-1 methylation. The CRC cell lines treated with 5-FU showed increased expression of LINE-1 mRNA. This was associated with upregulation of the phospho-histone H2A.X in cells with low LINE-1 methylation, but not in cells with high LINE-1 methylation. The 5-FU-mediated induction of phospho-histone H2A.X, a marker of DNA damage, was inhibited by knockdown of LINE-1. These results suggest that LINE-1 methylation is a novel predictive marker for survival benefit from adjuvant chemotherapy with oral fluoropyrimidines in CRC patients. This finding could be important for achieving personalized chemotherapy.

Helicobacter pylori infection promotes methylation and silencing of trefoil factor 2, leading to gastric tumor development in mice and humans.

BACKGROUND & AIMS: Trefoil factors (TFFs) regulate mucosal repair and suppress tumor formation in the stomach. Tff1 deficiency results in gastric cancer, whereas Tff2 deficiency increases gastric inflammation. TFF2 expression is frequently lost in gastric neoplasms, but the nature of the silencing mechanism and associated impact on tumorigenesis have not been determined. METHODS: We investigated the epigenetic silencing of TFF2 in gastric biopsy specimens from individuals with Helicobacter pylori-positive gastritis, intestinal metaplasia, gastric cancer, and disease-free controls. TFF2 function and methylation were manipulated in gastric cancer cell lines. The effects of Tff2 deficiency on tumor growth were investigated in the gp130(F/F) mouse model of gastric cancer. RESULTS: In human tissue samples, DNA methylation at the TFF2 promoter began at the time of H pylori infection and increased throughout gastric tumor progression. TFF2 methylation levels were inversely correlated with TFF2 messenger RNA levels and could be used to discriminate between disease-free controls, H pylori-infected, and tumor tissues. Genome demethylation restored TFF2 expression in gastric cancer cell lines, so TFF2 silencing requires methylation. In Tff2-deficient gp130(F/F)/Tff2(-/-) mice, proliferation of mucosal cells and release of T helper cell type-1 (Th-1) 1 cytokines increased, whereas expression of gastric tumor suppressor genes and Th-2 cytokines were reduced, compared with gp130(F/F)controls. The fundus of gp130(F/F)/Tff2(-/-) mice displayed glandular atrophy and metaplasia, indicating accelerated preneoplasia. Experimental H pylori infection in wild-type mice reduced antral expression of Tff2 by increased promoter methylation. CONCLUSIONS: TFF2 negatively regulates preneoplastic progression and subsequent tumor development in the stomach, a role that is subverted by promoter methylation during H pylori infection.

Thymidylate synthase locus LOH in combination with genotype has prognostic and predictive significance in colorectal cancer.

The aim of the current study was to investigate the prognostic and predictive significance of polymorphisms in the thymidylate synthase (TS) gene, alongside the loss of heterozygocity (LOH) at this gene locus in patients with colorectal cancer. Genotyping was carried out for a variable number tandem repeat (VNTR) polymorphism in the TS 5'-untranslated region, a G/C single nucleotide polymorphism (SNP) located within this VNTR, and for TS LOH status in 246 colorectal cancer and paired normal DNA samples. The results were analyzed in relation to clinicopathological features, including the prognostic and predictive significance of TS genotype in patients who underwent curative surgery. Complete VNTR, SNP and LOH information for TS was obtained in 226 cases. No significant associations were observed between normal tissue TS genotype status and clinicopathological features. LOH of TS was observed in 58% of tumor samples and was associated with poor prognosis independently of clinical stage. Cases exhibiting TS LOH were classified into the three groups of 2R/loss, 3G/loss and 3C/loss. Patients with 3C/loss genotype status had poor outcomes when treated by surgery alone, but their survival was similar to patients with other genotypes following Fluorouracil (5-FU)-based adjuvant chemotherapy. The results suggested that LOH of the TS locus may be a significant prognostic factor in colorectal cancer, with the genotype of the residual allele also demonstrating an influence on prognosis. In conclusion, LOH status should be considered when TS genotype is explored as a potential prognostic and predictive marker for 5-FU-based adjuvant chemotherapy in colorectal cancer.

Potential therapeutic effect of glycogen synthase kinase 3beta inhibition against human glioblastoma.

PURPOSE: Glioblastoma represents the malignant brain tumor that is most refractory to treatment and in which the identification of molecular target(s) is urgently required. We investigated the expression, activity, and putative pathologic role of glycogen synthase kinase 3beta (GSK3beta), an emerging therapeutic target for neurodegenerative diseases, in human glioblastoma. EXPERIMENTAL DESIGN: The active fraction of GSK3beta that is phosphorylated at the tyrosine 216 residue (pGSK3betaY216) was identified in glioblastoma cell lines. GSK3beta activity for phosphorylating its substrate was detected in these cells by nonradioisotopic in vitro kinase assay. RESULTS: Higher expression levels of GSK3beta and pGSK3betaY216 were frequently detected in glioblastomas compared with nonneoplastic brain tissues. Inhibition of GSK3beta activity by escalating doses of a small-molecule inhibitor (AR-A014418) or inhibition of its expression by RNA interference induced the apoptosis and attenuated the survival and proliferation of glioblastoma cells in vitro. Inhibition of GSK3beta was associated with increased expression of p53 and p21 in glioblastoma cells with wild-type p53 and with decreased Rb phosphorylation and expression of cyclin-dependent kinase 6 in all glioblastoma cell lines. Administration of AR-A014418 at a low dose significantly sensitized glioblastoma cells to temozolomide and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea, chemotherapeutic agents used in the clinical setting, as well as to ionizing radiation. CONCLUSION: These results indicate that GSK3beta exerts a pathologic role by promoting the survival and proliferation of glioblastoma cells and by protecting them from apoptosis via the inactivation of p53- and/or Rb-mediated pathways. Consequently, we propose that GSK3beta provides a potential therapeutic target in glioblastoma.

[DNA methylation and cancer metastasis].

Cancer cells acquire metastatic phenotypes by accumulating genetic and epigenetic abnormalities. DNA methylation is involved in epigenetic regulation of gene transcription and frequently altered with carcinogenesis. Two modes of aberrant DNA methylation, promoter hypermethylation and global hypomethylation, play a role in cancer metastasis with different mechanisms. Here, we discuss how the aberrant DNA methylation contributes to acquisition of metastatic phenotypes in cancer and review the recent trials for molecular diagnosis of cancer metastasis using methylation markers.

Different histological types of non-small cell lung cancer have distinct folate and DNA methylation levels.

Aberrant DNA methylation is a commonly observed epigenetic change in lung cancer. Folate has been suggested to play a role in the homeostasis of DNA methylation and has also been implicated in cancer chemotherapy. We investigated a possible role for folate in DNA methylation by measuring folate concentrations in tumors and adjacent normal tissues from 72 non-small cell lung cancer (NSCLC) patients. These were compared to DNA methylation levels and to clinicopathological features. Folate concentrations were determined as the sum of 5,10-methylenetetrahydrofolate and tetrahydrofolate. The MethyLight assay was used to quantitate methylation in promoter regions of P16(CDKN2A), APC, CDH13, RARB, RASSF1, RUNX3, and MYOD1. Methylation of LINE-1 repeats was used as a surrogate for global methylation. Folate levels in tumors correlated positively with LINE-1, CDH13, and RUNX3 methylation. Folate concentrations and methylation of LINE-1, RASSF1, and RUNX3 were significantly higher in adenocarcinoma compared to squamous cell carcinoma (SCC). Two sets of array-based data retrieved from the Gene Expression Omnibus consistently showed that expression of FOLR1, a folate transport enzyme, and GGH, an enzyme that prevents folate retention, were higher and lower, respectively, in adenocarcinomas compared to SCC. This was independently validated by quantitative RT-PCR in 26 adenocarcinomas and 13 SCC. Our results suggest that folate metabolism plays a role in aberrant DNA methylation in NSCLC. The histological subtype differences in folate concentration and DNA methylation observed here were associated with distinct expression patterns for folate metabolizing enzymes. These findings may have clinical applications for histology-directed chemotherapy with fluoropyrimidine and anti-folates in NSCLC.

Reduced perioperative immune response in video-assisted versus open surgery in a rat model.

PURPOSE: To establish the best technique for thoracoscopic pneumonectomy in the rat and to analyze the differences in perioperative immune response between open and video-assisted thoracoscopic surgery (VATS) in a rat model. METHODS: The four experimental groups studied were as follows: VATS pneumonectomy, open pneumonectomy, thoracoscopic observation, and open observation. We measured the immunocyte counts and serum cytokine levels postoperatively in each group. RESULTS: The CD3+, CD4+, and CD8+ lymphocyte counts were decreased significantly 12-24 h postoperatively in all groups. Immunosuppression peaked later in the open approach groups than in the VATS groups. The interleukin-6 level was significantly higher in the open approach groups than in the VATS groups. CONCLUSIONS: From the viewpoint of immunity, in this rat model VATS was less invasive than open surgery, and open surgery caused greater immunosuppression than VATS, irrespective of organ resection.

Quantitative detection of TIMP-3 promoter hypermethylation and its prognostic significance in esophageal squamous cell carcinoma.

Tissue inhibitor of metalloproteinase-3 (TIMP-3) has an inhibitory effect on tumor development, growth and metastasis due to its interaction with matrix metalloproteinases (MMPs). We investigated the prognostic significance of TIMP-3 gene promoter methylation in esophageal squamous cell carcinoma (ESCC). TIMP-3 methylation was analyzed by MethyLight, a quantitative and methylation-specific PCR method. Hypermethylation was found in 9/51 (18%) surgically resected ESCC samples and was associated with reduced disease-free (p=0.0039) and overall survival (p=0.0047). Upon multivariate analysis, it was found to be an independent prognostic parameter for poor survival and was associated with earlier recurrence after surgery (p=0.0238), especially via pleural dissemination (p=0.001). Expression levels for TIMP-3 protein and for several MMPs were analyzed by Western blot analysis in 20 pairs of ESCC and adjacent normal tissue. The expression of MMP-2, -7 and -9 proteins in tumor tissue was significantly higher than in corresponding normal mucosa (p=0.0051, 0.0064 and 0.0004, respectively). In contrast, the expression of TIMP-3 protein in tumor tissue was significantly lower than in matched normal mucosa (p=0.0152). Tumors with TIMP-3 hypermethylation expressed lower levels of TIMP-3 protein compared to those without hypermethylation (p=0.0357). These results demonstrate that TIMP-3 hypermethylation is associated with lower TIMP-3 protein expression in ESCC and with poor patient survival due to a high frequency of recurrence by pleural dissemination.

Phase II study of bevacizumab and irinotecan as second-line therapy for patients with metastatic colorectal cancer previously treated with fluoropyrimidines, oxaliplatin, and bevacizumab.

PURPOSE: Fluorouracil and folinic acid with irinotecan (FOLFIRI) plus bevacizumab (BV) is widely used as second-line chemotherapy for patients with metastatic colorectal cancer (mCRC) previously treated with fluoropyrimidines, oxaliplatin, and BV. FOLFIRI requires a CV catheter and an infusion pump, which are inconvenient for patients. Sufficient data are not available for characterizing the effectiveness of fluoropyrimidines beyond first disease progression. In this study, we evaluated the efficacy and safety of irinotecan (CPT-11) plus BV as second-line therapy. METHODS: Patients with mCRC previously treated with at least four courses of a fluoropyrimidine, oxaliplatin, and BV were designated to receive 150 mg/m2 of CPT-11 and 10 mg/kg of BV every 2 weeks as second-line therapy. The primary endpoint was progression-free survival (PFS), and secondary endpoints included response rate (RR), overall survival (OS), and adverse events. RESULTS: Thirty patients from six institutes were enrolled from March 2011 to January 2014. The median PFS was 5.7 months (95% CI 4.2-7.3 months), and the RR was 6.7% (range 0.8-22.1%). Grades 3-4 adverse events included leucopenia (36.7%), neutropenia (50%), thrombocytopenia (26.7%), anemia (30%), diarrhea (3.3%), anorexia (6.7%), and hypertension (3.3%). Relative dose intensities were 94.5 and 96.3% for CPT-11 and BV, respectively. The median OS was 11.8 months (6.3 months-not reached). CONCLUSIONS: Administration of CPT-11 plus BV to patients with mCRC achieved comparable efficacies with relatively lower toxicities compared with the results of previous studies using FOLFIRI plus BV as second-line therapy. The dose intensity of CPT-11 was judged as satisfactory. CLINICAL TRIAL INFORMATION: UMIN000005228.

BRAF mutations are associated with distinctive clinical, pathological and molecular features of colorectal cancer independently of microsatellite instability status.

BACKGROUND: BRAF is a member of RAF family of serine/threonine kinases and mediates cellular responses to growth signals through the RAS-RAF-MAP kinase pathway. Activating mutations in BRAF have recently been found in about 10% of colorectal cancers, with the vast majority being a V600E hotspot mutation. The aim of the present study was to evaluate the clinical, pathological and molecular phenotype of colorectal tumors with BRAF mutations. RESULTS: Mutations in BRAF were identified in 8% (23/275) of colorectal cancers. They were 5-10-fold more frequent in tumors with infiltrating lymphocytes, location in the proximal colon, poor histological grade and mucinous appearance (P < 0.002 for each). Tumors with BRAF mutation were also 10-fold more likely to show microsatellite instability and frequent DNA methylation (P < 0.0001) compared to tumors without this mutation. The characteristic morphological features of tumors with BRAF mutation (infiltrating lymphocytes, poor grade, mucinous) remained after stratification according to microsatellite instability and methylator phenotypes. Mutations in BRAF were mutually exclusive with mutations in KRAS but showed no clear association with the presence of TP53 mutation. CONCLUSION: BRAF mutation identifies a colorectal cancer subgroup with distinctive phenotypic properties independent of microsatellite instability status and thus could be a valuable marker for studies into the clinical properties of these tumors.

Detection of active fraction of glycogen synthase kinase 3beta in cancer cells by nonradioisotopic in vitro kinase assay.

Glycogen synthase kinase 3beta (GSK3beta) is a well-known marker and potential therapeutic target in non-insulin-dependent diabetes mellitus and Alzheimer's disease. Our recent demonstration that GSK3beta has a previously unrecognized role in colorectal cancer facilitates the development of a nonradioisotopic in vitro kinase assay (NRIKA) for detecting GSK3beta activity in gastrointestinal cancer cells. The NRIKA uses a sequential combination of immunoprecipitations to isolate GSK3beta in sample cells' lysates, and an in vitro kinase reaction that uses recombinant beta-catenin protein (substrate) and nonradioisotopic ATP, followed by immunoblotting to detect beta-catenin phosphorylated in serine 33, 37 and/or threonine 41 residues. The NRIKA detected higher expression of active GSK3beta in stomach, colon, pancreas and liver cancer cell lines than in human embryonic kidney cells (HEK293) considered nonneoplastic. Inhibition of cancer cell-derived GSK3beta activity by GSK3beta inhibitors (SB-216763, AR-A014418) was detected by the NRIKA. GSK3beta inhibition attenuated survival and proliferation and induced apoptosis in all types of cancer cells but not in HEK293. These findings supported the idea that the pathologic roles of GSK3beta are definite and common in various types of cancer. The NRIKA provides a basis for evolving a high-throughput tool for testing substances for GSK3beta inhibition, and for screening and identifying novel GSK3beta inhibitors with a view to discovering drugs for treatment of cancer as well as non-insulin-dependent diabetes mellitus and Alzheimer's disease.

Genotype of thymidylate synthase likely to affect efficacy of adjuvant 5-FU based chemotherapy in colon cancer.

Thymidylate synthase [TS, (EC 2.1.1.45)] is the target enzyme in 5-fluorouracil treatment. Recently, the DNA polymorphism of this gene has been found to affect TS protein (pTS) expression. However, no prospective studies have been performed to evaluate the influence of this polymorphism on the clinical efficacy of 5-FU-based adjuvant chemotherapy for colorectal cancer (CRC). In this study, we investigated the genotype of TS and immunopathological findings of pTS in 161 colon cancer specimens from patients who were registered in a prospective adjuvant immunochemotherapy clinical trial. The clinical course and prognosis of these patients were checked after the study had been completed. This study comprised 11 (6.8%) cases of 2R/2R, 40 (24.8%) of 2R/3R, and 110 (68.3%) of 3R/3R genotypes. All of the 2R/2R cases were still alive at the time of analysis although this finding was not statistically significant. In this prospective examination on a randomized controlled trial, the patients with colon cancer of the 2R/2R TS genotype may be good responders to 5-FU-based adjuvant chemotherapy. Furthermore, differences in the proportions of the TS genotypes can account for the interracial differences in the adverse effects of 5-FU-based chemotherapy.

In vitro sensitivity to platinum-derived drugs is associated with expression of thymidylate synthase and dihydropyrimidine dehydrogenase in human lung cancer.

Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are critical enzymes in nucleic acid metabolism. Proliferating cell nuclear antigen (PCNA) is a specific protein that is correlated with proliferative activity of cells. The TS gene has a variable number of tandem repeats (VNTR) in its 5'-untranslated region and a single nucleotide polymorphism (SNP) in the VNTR area. We examined the association of in vitro sensitivity to anticancer drugs with TS polymorphism, TS, DPD, and PCNA mRNA expression using human lung cancer tissues. Seventy-eight surgically resected lung cancer tissues were tested for in vitro sensitivity to 5-fluorouracil, cisplatin (CDDP), carboplatin (CBDCA), irinotecan, docetaxel, and gemcitabine by histoculture and MTT assay. The TS polymorphisms were analyzed by PCR and PCR-RFLP. TS, DPD, and PCNA mRNA expression levels were quantified by real-time RT-PCR and normalized relative to beta-actin mRNA expression. The inhibition rates (IRs) of CDDP and CBDCA were significantly correlated with TS/PCNA, the ratio of TS/actin and PCNA/actin, and DPD/PCNA, the ratio of DPD/actin and PCNA/actin. This correlation was further explored by subgroup analyses according to TS VNTR or TS functional type, in which 2R/3G, 3C/3G, or 3G/3G were classified into H-type group and 2R/2R, 2R/3C, or 3C/3C into L-type group. The associations of TS/PCNA and DPD/PCNA with the IRs of CDDP, CBDCA remained significant in the 3R/3R group and H-type group. These results suggest that in vitro sensitivity to platinum-derived drugs, CDDP and CBDCA, is associated with PCNA-normalized mRNA expression of TS and DPD in human lung cancer tissues, as affected by the TS polymorphism. The clinical significance of these pharmacogenomic markers for chemotherapy regimens with platinum-derived drugs should be investigated further for personalized treatment of lung cancer.

Prognostic significance of p16(INK4a) hypermethylation in non-small cell lung cancer is evident by quantitative DNA methylation analysis.

BACKGROUND: p16(INK4a) is a tumor suppressor gene frequently inactivated by aberrant promoter hypermethylation. In the present study, p16(INK4a) methylation was evaluated in non-small cell lung cancer (NSCLC) using a quantitative assay and the clinical significance of the methylation was explored. MATERIALS AND METHODS: A total of 244 tumor samples from formalin-fixed paraffin-embedded archives were examined in this study. p16(INK4a) methylation was analyzed by the fluorescence-based, real-time methylation-specific PCR assay, MethyLight. The quantitative methylation value was expressed as the percentage of methylated reference (PMR). RESULTS: The median level of p16(INK4) methylation was 0.55 PMR (range 0.00-503.4). The p16(INK4) methylation value was significantly higher in males (p = 0.005) and in squamous cell carcinoma (p = 0.018). Prognostic analysis using the Cox proportional hazard model showed that the p16(INK4a) methylation value was a significant prognostic factor (odds ratio, 1.005; 95% CI, 1.003 to 1.008; p < 0.0001). The p16(INK4a) methylation value remained a significant prognostic factor (p = 0.0004) in multivariate analysis including age, gender, histological type and clinical stage. Specimens were then classified into hypermethylated or non-hypermethylated groups based on the p16(INK4a) methylation value using various cut-offs from 1 to 100 PMR. There was no significant difference in prognosis between the two groups using a cut-off value of 1 PMR. On the other hand, there was a significant difference using 6 PMR or more as the cut-off value (p < 0.01). CONCLUSION: These results provide clear evidence for the prognostic significance of p16(INK4a) methylation in NSCLC using quantitative DNA methylation analysis. Careful assessment of DNA methylation is needed because qualitative methylation analysis may overestimate low levels of methylation, which have less clinical significance.