Breast Neoplasms ; genetics ; metabolism ; pathology ; Carcinoma, Ductal, Breast ; genetics ; metabolism ; pathology ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; DNA Methylation ; Female ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Humans ; Precancerous Conditions ; genetics ; metabolism ; pathology ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; rho GTP-Binding Proteins ; biosynthesis ; genetics

urpose: Misonidazole is a radiosensitizer that binds in hypoxic cells. The purpose of this study was to find out the feasibility of I-131-Iodomisonidazole (IMISO) for imaging of tumor hypoxia. MATERIALS AND METHODS: Tosyl precursor was dissolved in acetonitrile and I-131-NaI was added to synthesize IMISO. Balb/c mice inoculated with CT-26 adenocarcinoma were injected with IMISO. Mice were sacrificed at 1,2,4,24 hr and % of injected dose per gram of tissue (%ID/g) was determined. For scintigraphy and MRI, mouse bearing CT-26 adenocarcinoma was administered with IMISO and imaging was performed 4 hr after. Then, mouse body was fixed and microtomized slice was placed on radiographic film for autoradiography. RESULTS: %ID/g of tumor was 1.64 (1h), 0.98 (2h), 0.85 (4h) and 0.20 (24h), respectively. At 24h, %ID/g of tumor was higher than that of all other tissues except thyroid. Tumor to muscle ratio increased with time and tumor to blood ratio also increased with time and reached 1.53 at 24 hr. On autoradiogram, tumor was well visualized as an increased activity in central hypoxic area of the tumor which corresponds to the area of high signal intensity on T2-weighted MR image. On scintigraphy, tumor uptake was visualized. CONCLUSION:: This RESULTS suggest that IMISO may have a potential for tumor hypoxia imaging in mouse model. However, further study is needed to improve it's localization in tumor tissue and to achieve acceptable images of tumor hypoxia.
Adenocarcinoma* ; Animals ; Anoxia* ; Autoradiography ; Magnetic Resonance Imaging ; Mice* ; Misonidazole ; Radionuclide Imaging ; Thyroid Gland ; X-Ray Film

OBJECTIVETo investigate the promoter methylation status and mRNA expression of APC gene in MCF10 model of breast cancer progression.

METHODSMethylation specific PCR and sodium bisufite genomic sequencing were employed to detect the methylation status of APC promoter 1A in normal breast tissues, conventional breast cancer cell line MCF-7 and MCF10 model cell lines including MCF10A (breast hyperplastic cell line, non-tumorigenic), MCF10AT (pre-malignant cell lines, producing slowly progressing hyperplastic and dysplastic lesions), MCF10DCIS.com (breast ductal carcinoma in-situ cell line, producing ductal carcinoma in-situ), MCF10CA1a, MCF10CA1d, MCF10CA1h cell lines (invasive breast carcinoma cell line, forming aggressive tumors of different morphology and metastatic potential). In addition, mRNA expression of APC was determined by reverse transcriptase PCR and real-time PCR assays.

RESULTSHypomethylation of APC promoter 1A was identified in hyperplastic cell line MCF10A, pre-malignant cell line MCF10AT, ductal carcinoma in-situ cell line MCF10DCIS.com, invasive carcinoma cell lines MCF10CA1a, MCF10CA1d, MCF10CA1h and normal breast tissue. MCF-7 showed partial methylation at the promoter. Statistically significant reduction of APC mRNA expression was not found in all MCF10 cell lines and MCF-7, compared with that of normal breast tissue (MCF10AT, MCF10CA1a, MCF10CA1d, MCF10CA1h and MCF10DCIS.com showed reduced mRNA expressions of APC at 0.27, 0.96, 1.78, 2.70, and 2.03 times respectively. MCF10A and MCF-7 even showed an increase of APC mRNA expression at 0.02 and 0.33 times, respectively).

CONCLUSIONThe aberrant promoter methylation of APC is not related to the breast cancer progression, at least in the MCF10 model system.

Adenomatous Polyposis Coli Protein ; biosynthesis ; genetics ; Breast ; pathology ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; DNA Methylation ; Female ; Gene Expression Regulation, Neoplastic ; Genes, APC ; Humans ; Hyperplasia ; genetics ; metabolism ; pathology ; Precancerous Conditions ; genetics ; metabolism ; pathology ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; biosynthesis ; genetics

OBJECTIVETo investigate the role of WT1 gene in breast carcinogenesis by analyses of the promoter methylation status and mRNA expression of WT1 gene in MCF10 model system of breast cancer progression.

METHODSMethylation specific PCR and sodium bisufite genomic sequencing were employed to detect methylation status of WT1 promoter in normal breast tissue, traditional breast cancer cell line MCF7 and MCF10 model series, including MCF10A (breast hyperplastic cell line, non-tumorigenic), MCF10AT (pre-malignant cell line, forming slowly progressing hyper and dysplastic lesions), MCF10DCIS.com (breast ductal carcinoma in situ cell line, forming ductal carcinoma in situ), and three invasive cell lines with metastatic potential (MCF10CA1a, MCF10CA1d, and MCF10CA1h). Real time reverse transcription PCR assay was used to determine the mRNA expression levels of WT1 in various cell lines.

RESULTSHypermethylation of WT1 promoter was identified in MCF7 and all MCF10 model cell lines (MCF10A, MCF10AT, MCF10DCIS.com, MCF10CA1a, MCF10CA1d, and MCF10CA1h). Unexpectedly, an increased expression of WT1 mRNA was found in all MCF10 cell lines and MCF7 comparing with normal breast tissue [folds of overexpression: 3.23 (MCF10A), 1.94 (MCF10AT), 4.20 (MCF10CA1a), 1.53 (MCF10CA1d), 4.20 (MCF10CA1h), 4.35 (MCF10DCIS) and 28.69 (MCF7)].

CONCLUSIONSPromoter methylation does not silence the mRNA expression of WT1 during the development of breast cancer. Overexpression of WT1 occurs in the early stages of breast cancer development, suggesting its role as an oncogene rather than a tumor suppressor gene.

Base Sequence ; Breast ; pathology ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Carcinoma, Ductal, Breast ; genetics ; metabolism ; pathology ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; DNA Methylation ; DNA, Neoplasm ; genetics ; Disease Progression ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Hyperplasia ; genetics ; metabolism ; pathology ; Molecular Sequence Data ; Precancerous Conditions ; genetics ; metabolism ; pathology ; Promoter Regions, Genetic ; RNA, Messenger ; metabolism ; WT1 Proteins ; genetics ; metabolism

PURPOSE: I-131 labeled (2'-deoxy-2-iodo-p-D-arabinofuranosyl) adenine (IAD) may be involved in DNA synthesis during active proliferation of tumor cells. We conducted this study to find out the biodistribution of IAD and its feasibility for scintigraphic tumor imaging. MATERIALS AND METHODS: Tosyl acetyl-adenosine was dissolved in acetonitrile, and I-131-NaI was added and heated to synthesize IAD. Female Fisher 344 rats innoculated with breast tumor cells were injected witb 0.27 MBq of IAD. Rats were sacrificed at 0.5, 1, 2, 4, 24h and the % of injected dose per gram of tissue (%ID/g) was determined. For scintigraphy, rats bearing breast cancer were administered with 1.11 MBq of IAD and imaging was perforrned after 2 and 24h. Then, rat body was fixed and rnicrotomized slice was placed on radiographic film for autoradiography, RESULTS: %ID/g of tumor wa.' 0.74 (0.5h), 0.73 (1h), 0.55 (2h), 0.38 (4h), and 0.05 (24h), respectively. At 1h after injection, %ID/g of tumor was higher than that of heart (0.34), liver (0.42), spleen (0.47), kidney (0,69), muscle (0.14), bone (0.33) and intestine (0.51). However, %1D/g of tumor was lower than blood (1.06), lung (0.77), and thyroid (177.71). At 4h, %ID/g of tumor in comparison with other tissue did not change. Tumor contrast expressed by tumor to blood ratio was 0.69 and tumor to muscle ratio was 5.11 at 1h. However, these ratios did not improve through 24h. On autoradiogram and scintigraphy at 2 and 24 hour, the tumor was well visualized. CONCLUSION: This results suggest that Ial) may have a potential for tumor scintigraphy. However, further work is needed to improve localization in tumor tissue.
Adenine ; Animals ; Autoradiography ; Breast Neoplasms* ; Breast* ; DNA ; Female ; Heart ; Hot Temperature ; Humans ; Intestines ; Kidney ; Liver ; Lung ; Radionuclide Imaging* ; Rats* ; Spleen ; Thyroid Gland ; X-Ray Film

Central neurocytoma (CN) is a rare, benign brain tumor often located in the lateral ventricles. CN may cause obstructive hydrocephalus and manifest as signs of increased intracranial pressure. The goal of treatment for CN is a gross total resection (GTR), which often yields excellent prognosis with a very high rate of tumor control and survival. Adjuvant radiosurgery and radiotherapy may be considered to improve tumor control when GTR cannot be achieved. Chemotherapy is also not considered a primary treatment, but has been used as a salvage therapy. The radiological features of CN are indistinguishable from those of other brain tumors; therefore, many histological markers, such as synaptophysin, can be very useful for diagnosing CNs. Furthermore, the MIB-1 Labeling Index seems to be correlated with the prognosis of CN. We also discuss oncogenes associated with these elusive tumors. Further studies may improve our ability to accurately diagnose CNs and to design the optimal treatment regimens for patients with CNs.
Brain Neoplasms ; Drug Therapy ; Humans ; Hydrocephalus ; Intracranial Pressure ; Lateral Ventricles ; Neurocytoma* ; Oncogenes ; Prognosis ; Radiosurgery ; Radiotherapy ; Salvage Therapy ; Synaptophysin

Protein phosphatase 2A (PP2A) accounts for the majority of total Ser/Thr phosphatase activities in most cell types and regulates many biological processes. PP2A holoenzymes contain a scaffold A subunit, a catalytic C subunit, and one of the regulatory/targeting B subunits. How the B subunit controls PP2A localization and substrate specificity, which is a crucial aspect of PP2A regulation, remains poorly understood. The kinetochore is a critical site for PP2A functioning, where PP2A orchestrates chromosome segregation through its interactions with BubR1. The PP2A-BubR1 interaction plays important roles in both spindle checkpoint silencing and stable microtubule-kinetochore attachment. Here we present the crystal structure of a PP2A B56-BubR1 complex, which demonstrates that a conserved BubR1 LxxIxE motif binds to the concave side of the B56 pseudo-HEAT repeats. The BubR1 motif binds to a groove formed between B56 HEAT repeats 3 and 4, which is quite distant from the B56 binding surface for PP2A catalytic C subunit and thus is unlikely to affect PP2A activity. In addition, the BubR1 binding site on B56 is far from the B56 binding site of shugoshin, another kinetochore PP2A-binding protein, and thus BubR1 and shugoshin can potentially interact with PP2A-B56 simultaneously. Our structural and biochemical analysis indicates that other proteins with the LxxIxE motif may also bind to the same PP2A B56 surface. Thus, our structure of the PP2A B56-BubR1 complex provides important insights into how the B56 subunit directs the recruitment of PP2A to specific targets.
Amino Acid Motifs ; Binding Sites ; Cell Cycle Proteins ; chemistry ; Crystallography, X-Ray ; Humans ; Multienzyme Complexes ; chemistry ; Protein Phosphatase 2 ; chemistry ; Protein Structure, Quaternary ; Protein-Serine-Threonine Kinases ; chemistry

Objectives. Polymorphisms in metabolic genes which alter rates of bioactivation and detoxification have been shown to modulate susceptibility to colorectal cancer. This study sought to evaluate the colorectal cancer risk from environmental factors and to do polymorphism studies on genes that code for Phase I and II xenobiotic metabolic enzymes among Filipino colorectal cancer patients and matched controls. Methods. A total of 224 colorectal cancer cases and 276 controls from the Filipino population were genotyped for selected polymorphisms in GSTM1, GSTP1, GSTT1, NAT1 and NAT2. Medical and diet histories, occupational exposure and demographic data were also collected for all subject participants.Results. Univariate logistic regression of non-genetic factors identified exposure to UV (sunlight) (OR 1.99, 95% CI: 1.16-3.39) and wood dust (OR 2.66, 95% CI: 1.21-5.83) and moldy food exposure (OR 1.61, 95% CI:1.11-2.35) as risk factors; while the NAT2*6B allele (recessive model OR 1.51, 95% CI :1.06-2.16; dominant model OR 1.87, 95% CI: 1.05-3.33) and homozygous genotype (OR 2.19, 95% CI: 1.19-4.03) were found to be significant among the genetic factors. After multivariate logistic regression of both environmental and genetic factors, only UV radiation exposure (OR 2.08, 95% CI: 1.21-3.58) and wood dust exposure (OR 2.08, 95% CI: 0.95-5.30) remained to be significantly associated with increasing colorectal cancer risk in the study population.Conclusion. This study demonstrated that UV sunlight and wood dust exposure play a greater role in influencing colorectal cancer susceptibility than genotype status from genetic polymorphisms of the GST and the NAT` genes.
Colorectal Neoplasms ; Polymorphism, Genetic