Deoxypyrimidine-induced inhibition of the cytokinetic effects of 1-β-d-arabinofuranosyluracil

Summary Ara-U-induced S-phase accumulation and the interaction between high concentrations of ara-U (HiCAU) and ara-C were investigated in L1210 leukemia cells in vitro. Treatment of exponentially growing L1210 murine leukemia cells with ara-U (200–1000 m) for 48 h caused a dose-dependent accumulation of cells in the S-phase. The extent of this ara-U-induced S-phase accumulation correlated with ara-U incorporation into DNA and with increases of up to 172% and 464% in the specific activities of deoxycytidine kinase and thymidine kinase, respectively, over control values. Metabolism of 1 m ara-C following the exposure of cells to ara-U (1mm) resulted in 4.5 pmol ara-C DNA/mg protein vs 2.1 pmol/mg protein in control cells. Although 48-h exposure of cells to 200 and 400 m ara-U is not cytotoxic, it enhances the cytotoxicity of ara-C (10–100 m) 4- to 10-fold. Ara-U-induced S-phase accumulation is inhibited by deoxypyrimidine nucleosides but not by pyrimidine or deoxypurine nucleosides. Some of the ara-U and ara-C concentrations used in this study are achievable in clinical practice, and ara-U/ara-C interactions may explain in part the unique therapeutic utility of high-dose ara-C.Abbreviations ara-C 1--d-arabinofuranosylcytosine - ara-U 1--d-arabinofuranosyluracil - ara-CTP 1--d-arabinofuranosylcytidine triphosphate - HiDAC high-dose ara-C - HiCAU high concentrations of ara-U - dCTP deoxycytidine triphosphate - HiDAU high-dose ara-U - FiTC Fluoroisothiocyanate - dUDP deoxyuridine diphosphate - dUTP deoxyuridine triphosphate - dTTP thymidine triphosphate - BrdUrd bromodeoxyuridine - dCyd kinase deoxycytidine kinase Supported in part by grant CH-35H from the American Cancer Society, by Public Health Service grant CA-12197 from the National Cancer Institute, National Institutes of Health, and by the Gaston Cancer Society     

Expression of TGFβ-1 and EHD1 correlated with survival of non-small cell Lung cancer

Transforming growth factor-β1 (TGFβ-1) signaling is regulated by endocytotic pathway. To clarify the prognostic value of TGFβ-1 and to verify the involvement of endocytosis in drug resistance, we examined the expression of TGFβ-1 and Eps15 homology domain 1 (EHD1) in non-small cell lung cancer (NSCLC) and its association with tumor characteristics and survival of patients with NSCLC. Expression of TGFβ-1 and EHD1 was evaluated by immunohistochemistry in paraffin sections from 105 NSCLC patients. Overall survival (OS) was analyzed by Kaplan–Meier method, log-rank test, and multivariate Cox proportional hazard regression model. Positive immunostaining of TGFβ-1 and EHD1 was detected in 52.38 and 39.05 % of NSCLC samples, respectively. In non-adjuvant chemotherapy-treated group (P?=?0.006) and epidermal growth factor receptor (EGFR) (+) group (P?=?0.038), patients with TGFβ-1 expression had a longer OS. EHD1 negative expression predicted a longer OS (P?=?0.003), especially in EGFR (+) (P?=?0.006) and adjuvant chemotherapy-treated patients (P?=?0.003). NSCLC patients with concurrent positive TGFβ-1 and negative EHD1 (combined markers) were significantly correlated with better OS (P?=?0.001). American Joint Committee on Cancer (AJCC) status and combined markers were independent prognostic indicators for OS (HR (95 % CI) 1.576 (1.112–2.232), P?=?0.011 and HR 0.349 (0.180–0.673), P?=?0.002, respectively). We identified concordant TGFβ-1 positive and EHD1 negative as a strong favorable prognosis factor in NSCLC. Our results may help us to select and optimize strategies for individualized therapy.     

Loss of p53 enhances the function of the endoplasmic reticulum through activation of the IRE1α/XBP1 pathway

Altered regulation of ER stress response has been implicated in a variety of human diseases, such as cancer and metabolic diseases. Excessive ER function contributes to malignant phenotypes, such as chemoresistance and metastasis. Here we report that the tumor suppressor p53 regulates ER function in response to stress. We found that loss of p53 function activates the IRE1α/XBP1 pathway to enhance protein folding and secretion through upregulation of IRE1α and subsequent activation of its target XBP1. We also show that wild-type p53 interacts with synoviolin (SYVN1)/HRD1/DER3, a transmembrane E3 ubiquitin ligase localized to ER during ER stress and removes unfolded proteins by reversing transport to the cytosol from the ER, and its interaction stimulates IRE1α degradation. Moreover, IRE1α inhibitor suppressed protein secretion, induced cell death in p53-deficient cells, and strongly suppressed the formation of tumors by p53-deficient human tumor cells in vivo compared with those that expressed wild-type p53. Therefore, our data imply that the IRE1α/XBP1 pathway serves as a target for therapy of chemoresistant tumors that express mutant p53.     

Deletion of exons 1–3 of the MEN1 gene in a large Italian family causes the loss of menin expression

Multiple endocrine neoplasia type 1 (MEN1) syndrome is an autosomal dominant disease, characterized by parathyroid adenomas, endocrine gastroenteropancreatic tumors and pituitary adenomas, due to inactivating mutations of the MEN1 gene (chromosome 11q13). MEN1 mutations are mainly represented by nonsense, deletions/insertions, splice site or missense mutations that can be detected by direct sequencing of genomic DNA. However, MEN1 patients with large heterozygous deletions may escape classical genetic screening and may be misidentified as phenocopies, thereby hindering proper clinical surveillance. We employed a real-time polymerase chain reaction application, the TaqMan copy number variation assay, to evaluate a family in which we failed to identify an MEN1 mutation by direct sequencing, despite a clear clinical diagnosis of MEN1 syndrome. Using the TaqMan copy number variation assay we identified a large deletion of the MEN1 gene involving exons 1 and 2, in three affected family members, but not in the other nine family members that were to date clinically unaffected. The same genetic alteration was not found in a group of ten unaffected subjects, without family history of endocrine tumors. The MEN1 deletion was further confirmed by multiplex ligation-dependent probe amplification, which showed the deletion extended from exon 1 to exon 3. This new approach allowed us to correctly genetically diagnose three clinical MEN1 patients that were previously considered as MEN1 phenocopies. More importantly, we excluded the presence of genetic alterations in the unaffected family members. These results underline the importance of using a variety of available biotechnology approaches when pursuing a genetic diagnosis in a clinically suggestive setting of inherited endocrine cancer.     

Polymorphic variation of CYP1A1 is associated with the risk of gastric cardia cancer: a prospective case–cohort study of cytochrome P-450 1A1 and GST enzymes

Objective: To determine if genetic polymorphisms of CYP1A1, GSTM1, GSTP1, or GSTT1 are associated with an increased risk of developing esophageal squamous cell carcinoma (ESCC), gastric cardia cancer (GCC), or either in a high-risk Asian population. Methods: We conducted a case-cohort analysis with 5 years of prospective follow-up. The analytical cohort contained 642 individuals who participated in either the Dysplasia Trial (DT) or the General Population (GPT) of the Nutrition Intervention Trials conducted in Linxian, China, and included 131 cases of ESCC and 90 cases of GCC. Genotyping analysis was performed on DNA extracted from red blood cells using a PureGene kit (Gentra Systems, Inc., Minneapolis, MN) and real-time PCR analysis amplification (Taq-Man). Relative risks and 95% confidence intervals were estimated using the case – cohort estimator for the Cox proportional hazards models. p-values from nested models with genotyping variables came from score tests. Results: The relative risks for developing ESCC, GCC, or either cancer were calculated in the entire analytic cohort for GSTM1, P1*B (A313G), and T1 and CYP1A1*2A (T3801C) and *2C (A2455G) genotypes, and no significant associations were identified. However, because of the difference in cancer risks between the DT (9.3 cases per 1000 person years) and the GPT (5.3 cases), the analytical cohort was stratified by trial; the DT participants who were heterozygous or homozygous for the variant-allele at CYP1A1*2A had a reduced risk for developing GCC (adjusted RR (95%CI) 0.47 (0.23–1.00) p = 0.037). Conclusions: This study found an association for the CYP1A1*2A variant allele and a reduced risk of GCC in people at high risk for development of this disease. This finding is consistent with previous studies suggesting that substrates for the cytochrome P-450 1A1 metabolic pathway, such as polycyclic aromatic hydrocarbons, may be etiologically significant in this high-risk region.     

Aberrant Expression of Notch1 in Cervical Cancer

OBJECTIVE To investigate the putative role of the Notch1 receptor in cervical cancer carcinogenesis and progression. METHODS The expression of the Notch1 protein was analyzed by a Western-blotting approach in 40 cervical cancer and 30 normal cervical tissues. Some tissues were examined using RT-PCR to determine mRNA levels. Celluar localization of the Notch1 protein in the paraffin-embedded cervical tissues was also analyzed by immunohistochemistry. RESULTS The Notch1 protein was detected in all 30 normal cervical tissues. In contrast, only 6 samples of 40 cervical cancer tissues showed Notch1 expression. The level of the Notch1 protein expression was significantly lower in cervical cancer tissues than that in normal tissue samples. In agreement with these observations, levels of Notch1 mRNA were found to be substantially down-regulated in cervical cancer tissues. In the immunohistochemistry staining assay, the Notch1 protein was shown to localize predominantly in the cytoplasm and nucleoli of the normal cervical squamous epithelium of the cervix, but no staining was observed in the cervical cancer cells. Notch1 expression was observed to correlate with the clinical disease stage, but there were no correlations with age, tumor size, grade or lymph node metastasis （P〉0.05）. The levels of Notch1 protein expression were significantly higher in early stages （Ⅰ-Ⅱa, 66.7%） compared to those in the advanced stages （Ⅱb～Ⅳ,12.6%）（P=0.001）. CONCLUSION Notch1 may play a role as a tumor suppressor in cervical tumorigenesis. Determination of Notch1 expression may be helpful for preoperative diagnosis and accuracy of staging. But its clinical use for cervical cancer requires further investigation.     

Effect of HCMV IE1 Protein on Cytokines Secretion and Apoptosis of Macrophages

Objective： To investigate the effect of human cytomegalovirus （HCMV） IE1 protein on the secretory activity and apoptosis of macrophages. Methods： The eukaryotic expression vector pEGFP-C1/IE1 was used to transfect THP-1-macrophages. 48 h after transfection, the expression and localization of GFP or GFP-IE1 was observed under fluorescent microscope. The levels of IL-1β and TNF-α in the culture media were examined by ELISA, and the mRNA expression of them was analyzed by RT-PCR. Cell undergoing apoptosis were determined by flow cytometry using the propidium iodide （PI） staining method. The data were analyzed by SPSSI3.0. Results： As observed under fluorescent microscope, the expressions of GFP-IEI and GFP by plasmid pEGFP-C1/IE1 or pEGFP-C1 in THP-1-macrophages could be found in nuclei or whole cells. Conclusion： As demonstrated by RT-PCR and ELISA, mRNA and protein expressions of IL-1β and TNF-α and promotes apoptosis in THP-1-macrophages.     

Critical role of phosphorylation of serine 165 of YBX1 on the activation of NF-κB in colon cancer

Y-box binding protein 1 [YBX1] is a multifunctional protein known to facilitate many of the hallmarks of cancer. Elevated levels of YBX1 protein are highly correlated with cancer progression, making it an excellent marker in cancer. The connection between YBX1 and the important nuclear factor κB [NF-κB] has never been reported. Here, we show that overexpression of wild type YBX1 [WT-YBX1] activates NF-κB, suggesting that YBX1 is a potential NF-κB activator. Furthermore, using mass spectrometry analysis we identified novel phosphorylation of serine 165 [S165] on YBX1. Overexpression of the S165A-YBX1 mutant in either HEK293 cells or colon cancer HT29 cells showed dramatically reduced NF-κB activating ability as compared with that of WT-YBX1, confirming that S165 phosphorylation is critical for the activation of NF-κB by YBX1. We also show that expression of the S165A-YBX1 mutant dramatically decreased the expression of NF-κB-inducible genes, reduced cell growth, and compromised tumorigenic ability as compared with WT-YBX1. Taken together, we provide the first evidence that YBX1 functions as a tumor promoter via NF-κB activation, and phosphorylation of S165 of YBX1 is critical for this function. Therefore, our important discovery may lead to blocking S165 phosphorylation as a potential therapeutic strategy to treat colon cancer.     

Loss of fibroblast HIF-1α accelerates tumorigenesis

Solid tumors consist of malignant cells and associated stromal components, including fibroblastic cells that contribute to tumor growth and progression. Although tumor fibrosis and aberrant vascularization contribute to the hypoxia often found in advanced tumors, the contribution of hypoxic signaling within tumor-associated fibroblasts to tumorigenesis remains unknown. In this study, we used a fibroblast-specific promoter to create mice in which key hypoxia regulatory genes, including VHL, HIF-1α, HIF-2α, and VEGF-A, were knocked out specifically in tumor stromal fibroblasts. We found that loss of HIF-1α and its target gene VEGF-A accelerated tumor growth in murine model of mammary cancer. HIF-1α and VEGF-A loss also led to a reduction in vascular density and myeloid cell infiltration, which correlated with improved tumor perfusion. Together, our findings indicate that the fibroblast HIF-1α response is a critical component of tumor vascularization.     

Inhibition of Proliferation of Human Osteosarcoma Cells Transfected with PIN1 Antisense Gene

目的观察以pIRES2-EGFP质粒为载体的PIN1反义基因转染对人骨肉瘤细胞增殖的抑制作用。方法用不同量(0、20、50、100、200、250μL)的以pIRES2-EGFP质粒为载体包装的反义PIN1基因转染人骨肉瘤细胞系MG-63细胞,收集转染前后的培养细胞和上清液,用MTT法观测转染前后细胞生长曲线;用流式细胞仪观测细胞生长周期变化和细胞凋亡情况;用免疫印迹法(Western-blot)检测Pinl蛋白的表达变化;用逆转录聚合酶链式反应(RT-PCR)检测PIN1mRNA表达变化。结果MTT法和流式细胞仪显示反义PIN1基因转染能抑制细胞生长,促进其凋亡;Western-Blot结果表明转染反义Pin1基因的量越多,其灰度越低,测得空白对照组及不同量(0、20、50、100、200、250μL)的转染基因组其相应的吸光度比值分别为0．854±0．136、0．866±0．138、0．732±0．154、0．611±0．121、0．547±0．109、0．398±0．113、0．320±0．151,差异有显著性(P<0．05);RT-PCR检测其灰度比值分别为0．983±0．125、0．988±0．127、0．915±0．157、0．786±0．125、0．608±0．124、0．433±0．130、0．410±0．158,差异有显著件(P<0．05)。结论反义Pin1基因可封闭Pin1mRNA,使已转染反义Pin1基因的MG-63细胞表达的Pin1蛋白减少,从而抑制人骨肉瘤细胞MG- 63增殖。     

RARα1 control of mammary gland ductal morphogenesis and wnt1-tumorigenesis

Introduction  

Retinoic acid signaling pathways are disabled in human breast cancer suggesting a controlling role in normal mammary growth that might be lost in tumorigenesis. We tested a single receptor isotype, RARα1 (retinoic acid receptor isotype alpha, isoform 1), for its role in mouse mammary gland morphogenesis and mouse mammary tumor virus (MMTV)-wingless-related MMTV integration site 1 (wnt1)-induced oncogenesis.     

Phase II trial of sequential paclitaxel and 1 h infusion of bryostatin-1 in patients with advanced esophageal cancer

BACKGROUND: We sought to determine the response rate and toxicity profile of sequential paclitaxel and bryostatin-1, a novel, selective inhibitor of protein kinase C, in patients with advanced esophageal cancer. PATIENTS AND METHODS: Patients with advanced esophageal and gastroesophageal junction cancer were enrolled. All gave informed consent. They were initially treated with paclitaxel 90 mg/m(2) intravenously on Day 1 and bryostatin-1 50 mug/m(2) on Day 2 weekly for three consecutive weeks out of four. Because of severe myalgias, dosing was reduced to paclitaxel 80 mg/m(2) with bryostatin-1 40 mug/m(2) and then to paclitaxel 80 mg/m(2) with bryostatin-1 25 mug/m(2). RESULTS: Twenty-four patients were enrolled, with 22 assessable for response. The partial response rate was 27%. 10 patients treated with bryostatin-1 40-50 mug/m(2) had a response rate of 40 versus 17% at bryostatin-1 25 mug/m(2) (p-value = 0.3). Median time-to-progression was 3.7 months and median survival was 8.3 months. Grade 3/4 myalgias were seen in 50% of patients. Myalgias appeared to be related to bryostatin-1 dose. Because of toxicity, the trial was closed prior to full accrual. CONCLUSIONS: Despite potential anti-tumor activity of this combination in patients with advanced esophageal cancer, further development is not warranted, given the severe toxicity, especially myalgias, that were seen.     

High frequency of HIF-1α overexpression in BRCA1 related breast cancer

Hypoxia is a hallmark of cancer. Hypoxia inducible factor-1α (HIF-1α) is the key regulator of the hypoxia response. HIF-1α is overexpressed during sporadic breast carcinogenesis and correlated with poor prognosis. Little is known on the role of HIF-1α in hereditary breast carcinogenesis. A recent study suggests a role for BRCA1 in HIF-1α regulation. We therefore examined the expression of HIF-1α in BRCA1 related breast cancers. By immunohistochemistry we studied expression of HIF-1α and some of its downstream targets in 30 hereditary invasive breast cancers in comparison with 200 sporadic controls. HIF-1α overexpression was significantly more frequent in BRCA1 related breast cancers (27/30, 90%) than in sporadic controls (88/200, 44%) (P < 0.0001). 19/30 (63%) of BRCA1 tumors showed perinecrotic (hypoxia induced) and 8/30 (27%) a diffuse HIF-1α overexpression pattern, the latter more likely related to genetic alterations in oncogenes and tumor suppressor genes. In contrast, sporadic breast cancer HIF-1 expressing tumors showed an inverse ratio of perinecrotic/diffuse expression (31 vs. 69%, P = 0.0002). Glut-1 and CAIX, downstream HIF1 targets, were expressed in 27/30 (90%) and 15/21 (71%) of hereditary cases versus 54/183 (29%) and 24/183 (13%) in sporadic cases. p300 levels, necessary for HIF-1 downstream activation, were significantly higher in hereditary cases (20/21, 95%) compared to sporadic cases (91/183, 50%, P = 0.0001). In conclusion, in BRCA1 germline mutation related breast cancer, functional HIF-1α overexpression is seen at a much higher frequency than in sporadic breast cancer, mostly hypoxia induced. This points to an important role of hypoxia and its key regulator HIF-1α in hereditary breast carcinogenesis.