Sadanori Abe

Possible chemoresistance-related genes for gastric cancer detected by cDNA microarray

To identify chemoresistance‐related genes of gastric cancer, we utilized cDNA microarray technology. Thirty‐five gastric cancer specimens surgically resected at our institute between 1998 and 1999 were studied for quantification of expression of 6300 genes by means of oligonucleotide microarray methods, and the results were evaluated in comparison with the chemoresistance of the specimens, which was determined by MTT (tetrazolium‐based 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay. Inhibition rates (IR) were determined for cisplatin (DDP), 5‐fluorouracil (5‐FU), mitomycin C or doxorubicin. IR of 60% or more was regarded as sensitive to each agent, and IR of less than 40% was defined as resistant. Clustering was successfully completed for DDP, resulting in selection of 23 candidates as DDP‐resistance‐related genes, including vascular permeability factor, 2 membrane transporting subunits, and retinoblastoma‐binding protein‐1. In addition, further selection of DDP‐resistance‐related genes was performed according to these criteria: 1) Expression of the gene can be detected in more than 70% of resistant tumors. 2) Expression can be detected in less than 30% of sensitive tumors. 3) Expression in tumors is more than twice that of normal mucosa in more than 50% of specimens. Then, metallothionein‐IG and heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) were identified as candidate DDP‐resistance‐related genes. When known DDP‐resistance‐related genes were analyzed according to the MTT assay result, families of glutathione‐S‐transferase and cydooxygenase‐2 genes were also evaluated as resistance‐related genes. For 5‐FU resistance, dihydropyrimidine dehydrogenase and HB‐EGF‐like growth factor genes were also suggested to be resistance‐related genes. The present study demonstrated that oligonucleotide microarrays can provide information regarding chemoresistance factors in cancer. (Cancer Sci 2003; 94: 355–359)

Gastrointestinal stromal tumors treated by laparoscopic surgery: report of three cases.

Three cases of gastrointestinal stromal tumors (GIST) were treated by a laparoscopic wedge resection of the stomach. The tumor characteristics were confirmed to be nonepithelial, nonlymphomatous, nonmyogenic, and nonneurogenic gastrointestinal neoplasms with an uncertain origin which were CD34-positive and actin- and S-100-negative. The malignant potential was estimated based on the mitotic figures and growth rates. The results suggest that laparoscopic surgery is an adequate strategy for gastric submucosal tumors including GIST, and also indicates this technique to be a curative, safe, and minimally invasive procedure for both diagnosis and treatment.

Surgically treated Cronkhite-Canada syndrome associated with gastric cancer

Cronkhite-Canada syndrome is generally accepted to be a benign disorder, with 374 reported cases to the present. Worldwide, there have been 18 previously reported cases of Cronkhite-Canada syndrome associated with gastric cancer. In this report we describe a case of a 52-year-old man with the clinical features of Cronkhite-Canada syndrome combined with gastric cancer. Although the gastric tumor was located at the antrum of the stomach, we performed a total gastrectomy because of the edematous swelling and high risk of malignancy in the remnant stomach. As Cronkhite-Canada syndrome may be a premalignant condition for gastric cancer, as well as for colorectal cancer, we suggest periodic examination of the stomach, colon, and rectum for patients with Cronkhite-Canada syndrome.

UCN‐01 (7‐Hydoxystaurosporine) Inhibits in vivo Growth of Human Cancer Cells through Selective Perturbation of G1 Phase Checkpoint Machinery

Mechanisms underlying tumor sensitivity to the antitumor agent UCN‐01 (7‐hydroxystaurosporine) were examined in the nude mouse model using three human tumor xenografts, two pancreatic cancers (PAN‐3‐JCK and CRL 1420) and a breast cancer (MX‐1). UCN‐01 antitumor activity was evaluated in terms of relative tumor weights in treated and untreated mice bearing the tumor xenografts. The activity of cyclin‐dependent kinase 2 (CDK2), levels of p21 and p27 proteins, pRb status and cell cycle were evaluated. Induction of p21 and apoptosis were also assessed immuno‐histochemically in CRL 1420. UCN‐01 was administered intraperitoneally at a dose of either 5 or 10 mg/kg daily for 5 days followed by a further 5 injections after an interval of 2 days. UCN‐01 significantly suppressed the growth of both pancreatic cancers, but was ineffective against MX‐1. p21 protein expression was markedly induced in the UCN‐01‐sensitive pancreatic carcinoma xenografts at both doses, but p21 induction was only evident in the UCN‐01‐resistant MX‐1 at 10 mg/kg. MX‐1 exhibited CDK2 activity that was 6‐fold higher than that of pancreatic cancer strains, which may explain the resistance of MX‐1 to UCN‐01 despite the induction of p21 at the dose of 10 mg/kg. The UCN‐01‐sensitive tumors exhibited G1 arrest and increased levels of apoptosis, changes not observed in resistant MX‐1. In conclusion, it appears that a determining factor of in vivo UCN‐01 sensitivity involves the balance of CDK2 kinase activity and p21 protein induction, resulting in augmented pRb phosphorylation, G1 cell cycle arrest and apoptosis.

UCN-01 (7-hydroxystaurosporine) inhibits the growth of human breast cancer xenografts through disruption of signal transduction

Background7-Hydroxystaurosporine (UCN-01), originally isolated as a phospholipid-dependent protein kinase C inhibitor, has been shown to have antitumor activity against several human cancer cell lines. UCN-01 inhibits cell cycle progression from the G1 to S phase by inhibition of cyclin-dependent kinase (CDK) activity and induction of intrinsic CDK inhibitor protein, leading to dephosphorylation of retinoblastoma (Rb) protein.Materials and MethodsThe antitumor activity of UCN-01 has been investigated against three human breast carcinoma strains serially transplanted into nude mice, including estrogen-dependent MCF-7, Br-10, and estrogen-independent MX-1. When the inoculated tumors started growing exponentially, UCN-01 (7.5 mg/kg) was administered intraperitoneally on five consecutive days a week for 2 weeks. The antitumor effect was evaluated as the lowest T/C ratio (%) during the experiments, where T was the relative mean tumor weight of the treated group and C was that of the control group. At the end of UCN-01 administration expression of p21, a protein of the CDK inhibitor family, and phosphorylated and dephosphorylated Rb protein was detected by Western blotting using treated and control tumors.ResultsUCN-01 had activity against MCF-7 and Br-10, with the lowest T/C ratios of 25.0% and 27.0%, respectively, while MX-1 was resistant to UCN-01 with a T/C ratio of 65.9%. The antitumor spectrum of UCN-01 was different from that of other conventional agents such as doxorubicin and cyclophosphamide which were ineffective against Br-10 but were active against MX-1. Although p21 was induced in three tested strains by UCN-01, little dephosphorylated Rb protein was expressed in MX-1 compared with Br-10 and MCF-7 (in vitro).ConclusionUCN-01 appeared to be a promising agent for the treatment of breast cancer, with a different mode of action and antitumor spectrum from other currently available antitumor drugs.

UCN-01 (7-hydroxystaurosporine) enhances 5-fluorouracil cytotoxicity through down-regulation of thymidylate synthetase messenger RNA.

UCN‐01 (7‐hydroxystaurosporine) is a newly developed cell cycle inhibitor known to have several modes of action, including inhibition of cyclin‐dependent kinase, induction of p21 and suppression of pRb phosphorylation. In order to test a combination therapy of UCN‐01 and 5‐fluorouracil (5‐FU), growth inhibition of CRL 1420 (MIA PaCa‐2; undifferentiated pancreatic carcinoma) by four different treatments was measured using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay. The treatments used were UCN‐01 alone, 5‐FU alone, 5‐FU followed by UCN‐01 (5‐FU/UCN‐01) and UCN‐01 followed by 5‐FU (UCN‐01/5‐FU). We also assessed changes in thymidylate synthetase (TS) mRNA levels, TS activity, and 5‐FU incorporation by RNA (FRNA) for each treatment. Although treatment with UCN‐01 alone, 5‐FU alone, and 5‐FU/UCN‐01 inhibited CRL 1420 growth in a concentration‐dependent manner, treatment with UCN‐01/5‐FU inhibited the growth of CRL 1420 synergistically at less than 1 μg/ml drug concentration. The down‐regulation of TS mRNA by UCN‐01 resulted in stable total TS and decreased free TS, and UCN‐01/5‐FU resulted in enhanced thymidylate synthetase inhibition rate (TSIR) compared to UCN‐01 alone and 5‐FU/UCN‐01. This increased TSIR due to UCN‐01 pretreatment was accompanied by elevated F‐RNA concentrations in the UCN‐01/5‐FU treatment. The suppression of TS mRNA and TS activity by UCN‐01 may lead to higher sensitivity of tumor cells to 5‐FU and may explain the synergistic antitumor effect of UCN‐01/5‐FU. In conclusion, low concentrations of UCN‐01 (from 0.01 to 1 μg/ml) may be clinically useful, affording low cytotoxicity of UCN‐01, while enhancing the antitumor effect of 5‐FU.

ADENOCARCINOMA IN SITU ARISING FROM THE ECTOPIC SUBMUCOSAL CARDIAC GLANDS OF SHORT-SEGMENT BARRETT'S EPITHELIUM

Adenocarcinoma of the esophagocardiac junction is a condition difficult to define. It is often necessary to differentiate between esophagocardiac junctional adenocarcinoma and carcinoma in Barretts esophagus. We herein report a case of an 83‐year‐old Japanese man with adenocarcinoma in situ arising from ectopic submucosal cardiac glands in short‐segment Barretts epithelium, associated with squamous cell carcinoma. Despite the visualization of a nodule in short‐segment Barretts epithelium, we diagnosed the present case as one of esophagocardiac junctional cancer arising from ectopic submucosal cardiac glands, using Alcian‐blue staining.