Cell cycle regulation by the Wee1 Inhibitor PD0166285, Pyrido [2,3-d] pyimidine, in the B16 mouse melanoma cell line

Background  

Wee1 kinase plays a critical role in maintaining G2 arrest through its inhibitory phosphorylation of cdc2. In previous reports, a pyridopyrimidine molecule PD0166285 was identified to inhibit Wee1 activity at nanomolar concentrations. This G2 checkpoint abrogation by PD0166285 was demonstrated to kill cancer cells, there at a toxic highest dose of 0.5 μM in some cell lines for exposure periods of no longer than 6 hours. The deregulated cell cycle progression may have ultimately damaged the cancer cells. We herein report one of the mechanism by which PD0166285 leads to cell death in the B16 mouse melanoma cell line.     

Preoperative diagnosis of lymph node metastases in gastric cancer by magnetic resonance imaging with ferumoxtran-10

Background Knowledge regarding the presence and location of lymph node metastasis in gastric cancer is essential in deciding on the operative approach. Lymph node metastases have been diagnosed with imaging tests such as computed tomography (CT) and ultrasonography (US); however, the accuracy of such diagnoses, based on size and shape criteria, has not been adequate. Ferumoxtran-10 (Combidex; Advanced Magnetics) is a lymphotropic contrast agent for magnetic resonance imaging (MRI) whose efficacy for the detection of metastatic lymph nodes in various cancers has been reported by several investigators; however, its efficacy for this purpose has not been reported for gastric cancer. We investigated the efficacy of ferumoxtran-10-enhanced MRI for the diagnosis of metastases to lymph nodes in gastric cancer. Methods Seventeen consecutive patients who were diagnosed with a nonearly stage of gastric cancer were enrolled in the study. All the patients were examined by MRI (Signa Horizon 1.5 T; GE Medical; T2*-weighted images) before and 24 h after the intravenous administration of ultrasmall particles of superparamagnetic iron oxide — ferumoxtran-10 (2.6 mg Fe/kg of body weight) — and the presence or absence of metastasis was determined from the enhancement patterns. The imaging results were compared with the corresponding histopathological findings following surgery. Results Of 781 lymph nodes dissected during surgery, the imaging results of 194 nodes could be correlated with their histopathological findings. Fifty-nine lymph nodes from 11 patients had histopathological metastases. In nonaffected normal lymph nodes, we observed dark signal intensity on MRI caused by the diffuse uptake of the contrast medium by macrophages resident in the lymph nodes, which phagocytose the iron oxide particles of ferumoxtran-10. The number of phagocytic macrophages was decreased in metastatic lymph nodes, and they showed various patterns of decreased uptake of ferumoxtran-10. Three enhancement patterns were observed in lymph nodes: (A) lymph nodes with overall dark signal intensity due to the diffuse uptake of ferumoxtran-10; (B) lymph nodes with partial high signal intensity due to partial uptake; and (C) no blackening of lymph nodes due to no uptake of ferumoxtran-10. Patterns (B) and (C) were defined as metastatic. The sensitivity, specificity, positive predictive value, negative predictive value, and overall predictive accuracy of postcontrast MRI were 100% (59/59), 92.6% (125/135), 85.5% (59/69), 100% (125/125), and 94.8% (184/194), respectively. These parameters for predictive accuracy were much superior to these parameters previously evaluated by CT or US. Nodes in the retroperitoneal and paraaortic regions were more readily identified and diagnosed on the MR images than those in the perigastric region. Conclusion The present study confirmed that ferumoxtran-10-enhanced MRI is useful in the diagnosis of metastatic lymph nodes and that the use of this modality will be helpful in treatment decision-making for gastric cancer patients.     

小肠恶性淋巴瘤的细胞遗传学和临床病理学特征：应用荧光原位杂交技术检测26例患者组织石蜡切片的发现

目的：在小肠恶性淋巴瘤（SIML）中，特异性染色体异常和临床病理学特征的关系仍然不清楚。该研究目的是通过对石蜡组织切片进行荧光原位杂交（组织-FISH）发现影响BCL1、BCL2、C—MYC、BCL6和MALT1基因的染色体易位发生的频率。材料与方法：该研究以1996-2003年间26例通过病理学检查诊断为SIML患为研究对象。应用特异探针在石蜡组织切片上进行组织-FISH。结果：小肠恶性淋巴瘤的原发部位常见于十二指肠（9例，35％）。根据WHO分级标准，14例（53％）诊断为弥漫性大B细胞淋巴瘤（DLBCL），6例（23％）为黏膜相关淋巴组织（MALT）的边缘区B细胞淋巴瘤。肉眼见DLBCL和MALT淋巴瘤表现不同的特征。细胞遗传学方面，14例DLBCL患中3例（21％）检测到IGH—BCL2的易位，但是在MALT淋巴瘤中并未检测到该种易位。14例DLBCL患中5例（35％）可检测到BCL6易位，同时6例MALT淋巴瘤中检测到1例（17％）BCL6易位。     

Prevention by long-term fermented miso of induction of colonic aberrant crypt foci by azoxymethane in F344 rats.

The present study was designed to investigate the effects of fermented miso in the diet on the induction of aberrant crypt foci (ACF) by azoxymethane (AOM) in male F344 rats. A total of 50 rats, 8 weeks of age, were divided into 5 groups and given weekly subcutaneous injections of AOM (15 mg/kg body wt) for 3 weeks. Rats were fed a normal control MF solid diet, or solid diet containing 10% long-term fermented (aged), medium- or short-term fermented miso, or 2.2% NaCl for 5 weeks, starting one week before the first AOM dosing. It was found that, compared to the control (MF) diet, the long-term fermented diet significantly decreased (by 22.2%) ACF/colon, but increased (by 18.2%) the number of aberrant crypts (Acs)/focus. The latter was also increased by the medium-term fermented diet (by 25.3%). The PCNA labeling index was only affected by the short-term fermented diet (36.9% increase) and by 2.2% NaCl diet (27.2% increased). The present results indicate that aged or completely fermented miso supplemented into the diet, could act as a chemopreventive agent for colon carcinogenesis.     

Telomerase activity in needle biopsied uterine myoma-like tumors: differential diagnosis between uterine sarcomas and leiomyomas.

Preoperative differential diagnoses between uterine sarcomas and leiomyomas are difficult. As telomerase activation is thought to be essential for the immortality of malignant cells, it is considered a potentially useful diagnostic marker. The aim of the present study was to evaluate the potential diagnostic use of measuring telomerase activity in needle biopsy samples to distinguish uterine sarcoma from leiomyoma. Sixty-two patients with suspected uterine sarcomas based on clinical findings or magnetic resonance imaging findings, and who were scheduled for surgery, underwent transcervical ultrasound-guided needle biopsy. Three samples were obtained per patient for histopathological examination and telomerase activity measurement. Telomerase activity was measured using the telomeric repeat amplification protocol and correlated with final histopathological findings of surgical specimens. Of the 62 patients, 6 leiomyosarcomas and 1 endometrial stromal sarcoma (high grade) were diagnosed by histopathology. In 6 of the 7 samples from uterine sarcomas, relatively high telomerase activity (22-102 units) was detected, whereas only low telomerase activity (11-18 units) existed in 3 of the remaining 55 samples from benign or borderline uterine smooth muscle tumors. At a cut-off value of 20 units, sensitivity, specificity, positive predictive, and negative predictive values for detecting uterine sarcoma were 86% (95% confidence interval, 59-100%), 100% (94-100%), 100% (54-100%) and 98% (95-100%), respectively. The results indicated that telomerase activity in needle biopsy samples is a useful diagnostic marker to distinguish uterine sarcoma from leiomyoma.     

Immunohistochemical assessment of localization and frequency of micrometastases in lymph nodes of colorectal cancer.

PURPOSE: Micrometastases are often found in regional lymph nodes of colorectal cancer (CRC). The aim of this study is to examine the extent and distribution of such lymph nodes. EXPERIMENTAL DESIGN: We immunohistochemically assessed localization and frequency of micrometastases in 878 lymph nodes from 98 patients with CRC. The anatomical position of lymph nodes was defined as level 1 to level 3 according to distance from the main tumor. RESULTS: The frequency of micrometastasis increased through observation of the 4-microm-thick lymph node sections, from one to two to five slices. With five slices, micrometastasis was frequently and extensively present in 49.1, 35.7, and 53.3% patients of histologically node-negative patients, node-positive patients at level 1, and node-positive patients at level 2, respectively. We then assessed the value of the presence of micrometastasis in node-negative patients with regard to prognosis, but no significant impact was obtained. To examine the reproducibility of the results obtained with immunohistochemistry, serial sectioning (four consecutive slices at seven different levels) of lymph nodes was additionally performed in lymph nodes initially diagnosed as micrometastasis positive. Immunohistochemical detection revealed that the sectioning level highly affected the results. CONCLUSIONS: Our results indicated frequent presence of micrometastasis in lymph nodes of CRC and that micrometastasis in node-negative CRC patients did not help in predicting the outcome, in part because of the limited reproducibility with immunohistochemistry.     

Increased MCL-1 expression is associated with poor prognosis in ovarian carcinomas.

To investigate the potential role of the BCL-2 gene family (BAX, BCL-2, MCL-1, and BCL-XL) in ovarian cancer development and progression, mRNA expression levels of these genes were measured using semi-quantitative PCR in epithelial ovarian tumor tissues and normal ovaries. The immunohistochemical expression of MCL-1 in ovarian tumors was also examined. The expression levels of BAX and MCL-1 mRNA were significantly higher in ovarian cancers and in adenomas than in normal ovaries (P < 0.05). In contrast, the BCL-2 mRNA expression level in ovarian cancers was significantly lower than in ovarian adenomas and in normal ovaries (P < 0.05). Expression of BCL-XL mRNA was no different between normal ovaries and ovarian tumors. Log-rank testing showed that low BAX mRNA expression and high MCL-1 mRNA expression significantly correlate with poor survival for patients with stage III ovarian carcinomas (BAX, P = 0.05; MCL-1, P = 0.02). Immunohistochemical analysis showed that diffuse-positive expression of MCL-1 protein in mucinous carcinomas was significantly higher than in mucinous low malignant potential (LMP) tumors (P = 0.03). In ovarian cancer cases, diffuse-positive expression of MCL-1 protein significantly correlates with advanced clinical stage, high histologic grade, and poor survival (stage, P < 0.01; grade, P = 0.01; survival, P = 0.01). These results suggest that increased MCL-1 expression may play an important role in replacing the functions of increased BAX and decreased BCL-2 in ovarian carcinoma cells, thereby promoting cell survival, and resulting in a poor prognosis for patients with ovarian cancer.     

The mouse rasH2/BHT model as an in vivo rapid assay for lung carcinogens.

We have demonstrated the utility of a 9-week in vivo two-stage assay for lung cancer initiating agents, using transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) and butylhydroxytoluene (BHT) as a potent lung promoter (rasH2/BHT model). In the present study, to ascertain appropriate conditions for BHT administration in this model, the effects of exposure on proliferation of alveolar type II cells in male rasH2 mice were examined. Additionally, use of BHT was validated for promotion of urethane (UR) carcinogenesis in male and female rasH2 mice. In a time-course study of a single intragastric administration of BHT at a dose of 400 mg/kg, increased bromodeoxyuridine-labeling index (LI) reached a maximum 3 days after treatment and was still observed after 7 days. In a dose-response study, effects were dose-dependent, the dose of 400 mg/kg causing eight-fold elevation as compared to the control. With repeated administration, whereas the LI was increased dramatically at first, effects gradually diminished with further exposure, and finally six BHT treatments failed to induce cell proliferation. In a two-stage model using UR as the initiator, although up to five consecutive doses of BHT were able to exert continued enhancing effects in terms of adenoma yield, no increment was evident with further treatments. The data overall indicate that a rasH2/BHT model with five weekly administrations of BHT at a dose of 400 mg/kg is most efficacious.     

Significant growth inhibition of human lung cancer cells both in vitro and in vivo by the combined use of a selective cyclooxygenase 2 inhibitor, JTE-522, and conventional anticancer agents.

This study reports that a selective COX-2 inhibitor JTE-522inhibits both in vitro and in vivo growth of human lung cancer cells as a single agent. Furthermore, the adjunct use of JTE-522 is shown to significantly enhance treatment efficacy of conventional anticancer drugs not only in vitro but also in vivo without causing any noticeable side effects. Indeed, IC(50)s of various anticancer agents in vitro were reduced by up to 70%, whereas the combination therapy of JTE-522 with docetaxel and vinorelbine inhibited tumor growth in vivo by 65 and 55%, respectively. Taken together, these findings suggest that the use of a selective COX-2 inhibitor in the treatment of lung cancer may be promising, especially because of its enhancement of the treatment efficacy of conventional anticancer agents without compromising quality of life.