Differences in the association of p53 phosphorylated on serine 15 and key enzymes of homologous recombination

Phosphorylation of p53 on serine 15 by ATM or ATR is a frequent modification and initiates a cascade of post-translational modifications. To identify possible mechanisms that modulate p53 functions in recombination surveillance, we compared the nuclear localization of p53 phosphorylated on serine 15 (p53pSer15) and the key enzymes of homologous recombination (HR) after replication fork stalling. We demonstrate an almost mutually exclusive subcompartmentalization with Rad52, while p53pSer15 was colocalizing with 40-60% of the Rad51 and Mre11 foci. Therefore, possible sites of p53pSer15-dependent regulation seem to be sites of Rad51- rather than Rad52-dependent HR processes. Remarkably, the association of p53pSer15 with repair complexes containing Rad51 or Mre11 was transient, because less than 20% of the Rad51 and Mre11 foci overlapped with p53pSer15 after 6 h. When we examined colocalization and co-immunoprecipitation of p53pSer15 and the RecQ helicase BLM with recombination surveillance and proapoptotic functions, we observed colocalization within a fraction of approximately 70% of the BLM foci and stable physical interactions until 6 h after replication arrest. Our data suggest that p53pSer15 plays a dual role in the functional interactions with early complexes of Rad51-dependent recombination and with BLM-associated surveillance and signalling complexes within distinct nuclear subcompartments.     

Taking CHARGE: A self-management program for women following breast cancer treatment

The purpose of the study was to develop and evaluate Taking CHARGE, a self-management intervention designed to facilitate successful transitions to survivorship after breast cancer treatment. The Taking CHARGE intervention involves a two-pronged approach building on self-regulation principles to (1) equip women with self-management skills to address concerns following breast cancer treatment, and (2) provide information about common survivorship topics. The program involved four intervention contacts, two small group meetings and two individualized telephone sessions, delivered by nurse/health educators. This paper focuses on the process evaluation findings from a preliminary test of the Taking CHARGE intervention conducted with 25 women, aged 34-66 years, completing breast cancer treatment, who were randomly assigned to the intervention group. The process evaluation was conducted to obtain systematic information about the relevance and usefulness of the self-regulation approach, informational aspects, and program delivery. The findings indicated that intervention group participants found the Taking CHARGE program to be timely, relevant, and to have high utility in dealing with concerns that exist following breast cancer treatment. The process evaluation findings provide early evidence of the usefulness of the Taking CHARGE intervention for successful transition to survivorship following breast cancer treatment.     

Molecular and cytological features of the mouse B-cell lymphoma line iMycEμ-1

Background

Myc-induced lymphoblastic B-cell lymphoma (LBL) in iMyc^Eμ mice may provide a model system for the study of the mechanism by which human MYC facilitates the initiation and progression of B cell and plasma cell neoplasms in human beings. We have recently shown that gene-targeted iMyc^Eμ mice that carry a His₆-tagged mouse Myc cDNA, Myc ^His, just 5' of the immunoglobulin heavy-chain enhancer, Eμ, are prone to B cell and plasma cell tumors. The predominant tumor (~50%) that arose in the iMyc^Eμ mice on the mixed genetic background of segregating C57BL/6 and 129/SvJ alleles was LBL. The purpose of this study was to establish and characterize a cell line, designated iMyc^Eμ-1, for the in-depth evaluation of LBL in vitro.

Methods

The morphological features and the surface marker expression profile of the iMyc^Eμ-1 cells were evaluated using cytological methods and FACS, respectively. The cytogenetic make-up of the iMyc^Eμ-1 cells was assessed by spectral karyotyping (SKY). The expression of the inserted Myc ^His gene was determined using RT-PCR and qPCR. Clonotypic immunoglobulin gene arrangements were detected by Southern blotting. The global gene expression program of the iMyc^Eμ-1 cells and the expression of 768 "pathway" genes were determined with the help of the Mouse Lymphochip^© and Superarray^© cDNA micro- and macroarrays, respectively. Array results were verified, in part, by RT-PCR and qPCR.

Results

Consistent with their derivation from LBL, the iMyc^Eμ-1 cells were found to be neoplastic IgM^highIgD^low lymphoblasts that expressed typical B-cell surface markers including CD40, CD54 (ICAM-1), CD80 (B7-1) and CD86 (B7-2). The iMyc^Eμ-1 cells harbored a reciprocal T(9;11) and three non-reciprocal chromosomal translocations, over-expressed Myc ^His at the expense of normal Myc, and exhibited gene expression changes on Mouse Lymphochip^© microarrays that were consistent with Myc ^His-driven B-cell neoplasia. Upon comparison to normal B cells using eight different Superarray^© cDNA macroarrays, the iMyc^Eμ-1 cells showed the highest number of changes on the NFκB array.

Conclusion

The iMyc^Eμ-1 cells may provide a uniquely useful model system to study the growth and survival requirements of Myc-driven mouse LBL in vitro.     

Racial and Ethnic Approaches to Community Health (REACH) Detroit partnership: improving diabetes-related outcomes among African American and Latino adults

OBJECTIVES: We sought to determine the effects of a community-based, culturally tailored diabetes lifestyle intervention on risk factors for diabetes complications among African Americans and Latinos with type 2 diabetes. METHODS: One hundred fifty-one African American and Latino adults with diabetes were recruited from 3 health care systems in Detroit, Michigan, to participate in the Racial and Ethnic Approaches to Community Health (REACH) Detroit Partnership diabetes lifestyle intervention. The curriculum, delivered by trained community residents, was aimed at improving dietary, physical activity, and diabetes self-care behaviors. Baseline and postintervention levels of diabetes-specific quality-of-life, diet, physical activity, self-care knowledge and behaviors, and hemoglobin A1C were assessed. RESULTS: There were statistically significant improvements in postintervention dietary knowledge and behaviors and physical activity knowledge. A statistically significant improvement in A1C level was achieved among REACH Detroit program participants (P<.0001) compared with a group of patients with diabetes in the same health care system in which no significant changes were observed (P=.160). CONCLUSIONS: A culturally tailored diabetes lifestyle intervention delivered by trained community residents produced significant improvement in dietary and diabetes self-care related knowledge and behaviors as well as important metabolic improvements.     

Breast cancer treatment experiences of Latinas in Los Angeles County

OBJECTIVE: We examined breast cancer treatment experiences of and outcomes for Latinas in Los Angeles County. METHODS: We conducted a population-based survey of women who were diagnosed with breast cancer between December 2001 and November 2002 (n=910) to evaluate the types of treatments received, communication with clinicians, and satisfaction. RESULTS: About two thirds were non-Latina White, 18.8% were African American, and 18.9% were Latina (with 11.0% preferring English and 7.9% preferring Spanish). The rest indicated other ethnic groups. Latinas who preferred Spanish were more likely to experience a delay of 3 months or more from diagnosis to surgical treatment (36.4% vs 9.1% for non-Latina Whites, 18.6% for African Americans, and 12.7%, for other Latinas, P<.001). African Americans and Latinas who preferred Spanish had very low rates of reconstruction (13.8% and 9.2%, respectively, compared with 42.1% for Whites and 34.5% for Latinas who preferred English, P=.009). Latinas who preferred Spanish had the highest odds ratio for low satisfaction. CONCLUSION: Latinas who preferred Spanish received different treatments and perceived a different treatment experience than did other cultural groups.     

Impact of exercise on overnight glycemic control in children with type 1 diabetes mellitus

OBJECTIVE: To examine the effect of exercise on overnight hypoglycemia in children with type 1 diabetes mellitus (T1DM). STUDY DESIGN: At 5 clinical sites, 50 subjects with T1DM (age 11 to 17 years) were studied in a clinical research center on 2 separate days. One day included an afternoon exercise session on a treadmill. On both days, frequently sampled blood glucose levels were measured at the DirecNet central laboratory. Insulin doses were similar on both days. RESULTS: During exercise, plasma glucose levels fell in almost all subjects; 11 (22%) developed hypoglycemia. Mean glucose level from 10 pm to 6 am was lower on the exercise day than on the sedentary day (131 vs 154 mg/dL; P=.003). Hypoglycemia developed overnight more often on the exercise nights than on the sedentary nights (P=.009), occurring on the exercise night only in 13 (26%), on the sedentary night only in 3 (6%), on both nights in 11 (22%), and on neither night in 23 (46%). Hypoglycemia was unusual on the sedentary night if the pre-bedtime snack glucose level was>130 mg/dL. CONCLUSIONS: These findings indicate that overnight hypoglycemia after exercise is common in children with T1DM and support the importance of modifying diabetes management after afternoon exercise to reduce the risk of hypoglycemia.     

Everyday activity predicts bone geometry in children: the iowa bone development study

PURPOSE: Bone adapts to changing mechanical loads by altering the structure appropriately. These adaptations should be evident in the bone cross-sectional area (CSA) and section modulus (Z), indices of axial and bending strength, respectively. In this cross-sectional study, we investigated associations between physical activity, CSA, and Z in 467 young children (mean age 5.2 yr). We also examined whether lean tissue mass, which is predominantly muscle, mediates the relationship between physical activity and bone structural measures. METHODS: Physical activity was assessed using accelerometry and questionnaire. Proximal femur measures of the neck, intertrochanteric, and shaft CSA (cm) and Z (cm) were derived from dual-energy x-ray absorptiometry (DXA) scans using the Hip Structure Analysis program. Total body lean mass (kg) was also measured using DXA. RESULTS: Boys were more physically active than girls. Boys also had greater CSA, Z, and lean mass than girls. At each region, time spent in vigorous activity was positively and consistently associated with CSA and Z in boys and girls (r = 0.19 to 0.32). After adjustment for age, body mass, and height, vigorous activity explained, on average, 6.9% of the variability in CSA and Z. With additional adjustment for lean mass, vigorous activity explained 3.7% of the remaining variability in CSA and Z. CONCLUSION: This study demonstrates that everyday amounts of physical activity in healthy, normal children are associated with bone geometry and that differences in lean mass explain some, but not all, of this association. This suggests that, even in young, nonathletic children, bone may adapt to physical activity by structurally remodeling.     

Moderate hypermutability of a transgenic lacZ reporter gene in Myc-dependent inflammation-induced plasma cell tumors in mice

Mutator phenotypes, a common and largely unexplained attribute of human cancer, might be better understood in mouse tumors containing reporter genes for accurate mutation enumeration and analysis. Previous work on peritoneal plasmacytomas (PCTs) in mice suggested that PCTs have a mutator phenotype caused by Myc-deregulating chromosomal translocations and/or phagocyte-induced mutagenesis due to chronic inflammation. To investigate this hypothesis, we generated PCTs that harbored the transgenic shuttle vector, pUR288, with a lacZ reporter gene for the assessment of mutations in vivo. PCTs exhibited a 5.5 times higher mutant frequency in lacZ (40.3 +/- 5.1 x 10(-5)) than in normal B cells (7.36 +/- 0.77 x 10(-5)), demonstrating that the tumors exhibit the phenotype of increased mutability. Studies on lacZ mutant frequency in serially transplanted PCTs and phagocyte-induced lacZ mutations in B cells in vitro indicated that mutant levels in tumors are not determined by exogenous damage inflicted by inflammatory cells. In vitro studies with a newly developed transgenic model of inducible Myc expression (Tet-off/MYC) showed that deregulated Myc sensitizes B cells to chemically induced mutations, but does not cause, on its own, mutations in lacZ. These findings suggested that the hypermutability of PCT is governed mainly by intrinsic features of tumor cells, not by deregulated Myc or chronic inflammation.