Women constitute approximately 45% of the postdoctoral fellows in the biomedical sciences at universities and research institutions in the USA, but a much lower percentage of women hold faculty positions. In the US National Institutes of Health (NIH; Bethesda, MD) Intramural Research Program, for example, women make up only 29% of the tenure-track investigators and hold just 19% of the tenured senior investigator appointments. A similar disparity between the ratio of men and women in independent faculty positions exists in most academic institutions across the USA (Nelson, 2005; NSF, 2004 NSF, , 2006, and statistics from Europe show a similar trend of women disappearing from the higher echelons of academia (EC, 2006).The transition from postdoctoral fellow to faculty is a period during which a worrying number of women leave academic research. Several recent surveys have tried to identify factors that lead to the attrition of women from the life sciences and engineering (University of California, 2005; Princeton University, 2003; University of Michigan, 2004;Baltimore et al, 2005), but these have not addressed the important question: why are female postdoctoral fellows falling off the academic bandwagon in greater numbers than male postdoctoral fellows?During the past ten years, the percentage of women in tenured positions at the NIH increased slightly, from 18% to 19%, but the percentage of women in tenuretrack positions remained unchanged. These facts led to the establishment of the Second Task Force on the Status of NIH Intramural Women Scientists. As part of this task force, the Postdoctoral Fellows Subcommittee set out to identify factors that might influence the decision of female postdoctoral fellows to pursue a position as a principal or independent investigator (PI). As several studies have previously identified family demands and self-confidence as factors that generally draw women away from the workforce at large (Kaplan & Granrose, 1993; Sears, 2003;Mason & Goulden, 2004;Hoonakker & Schoepke, 2005), our survey included questions to determine how these and other factors affect young female scientists in their career choices at the postdoc to PI transition.More than 1,300 intramural postdoctoral fellows at the NIH-from a total of 2,437-took part in a web-based survey. Of these, 43% were women and 57% were men, which reflects the nationwide gender distribution of postdoctoral fellows in the biological sciences (Nelson, 2005; NSF, 2004 NSF, , 2006. Although the age distribution was the same for men and women in this sample group, there was a clear difference between the percentage of men (44%) and the percentage of women (33.6%) with children (Table 1). Women with children are underrepresented in the postdoctoral workforce.The substantially lower percentage of female PIs could simply indicate that women are less likely to consider or pursue a career as a PI; therefore, we asked NIH fellows what type of career they were considering. More than two-thirds of the men but one-half of the women answered t...

Loss of or lowered retinoblastoma (Rb) expression has been included as a prognostic indicator in breast cancer. Low or no Rb expression is seen most commonly in high-grade breast adenocarcinomas, suggesting that a relationship may exist between loss of Rb and a less differentiated state, high proliferation rate, and high metastatic potential. In this study, we compared Rb function in two established breast adenocarcinoma cell lines, MCF-7 and MDA-MB-231, and in an established immortalized mammary epithelial cell line, MCF10A. Cells were synchronized in G0/G1 and were released for several durations, at which time total Rb protein, mRNA, and Rb/E2F/DNA complex formation were evaluated. Rb protein was significantly higher in the tumor cells than in MCF10A cells. However, Rb function was high for a longer duration in MCF10A cells as compared with MCF-7 and MDA-MB-231 cells. Our data support the general conclusion that Rb function, but not necessarily Rb protein, is lower in highly malignant breast adenocarcinoma cells as compared with lower grade tumor cells. These results emphasize the relevance of assessing Rb function over Rb protein. This is particularly important if Rb is to be used as a prognostic indicator for breast adenocarcinoma.

Our previous work has shown that the progesterone receptor (PR) can exist in two distinct functional states in mammary adenocarcinoma cells. The differences in function included the ability to activate a promoter in organized chromatin, sensitivity to ligand, and ligandindependent activation. To determine whether these functional differences were because of altered cellular processing, we carried out biochemical analyses of the functionally distinct PRs. Although the majority of PR is localized to the nucleus, biochemical partitioning resulted in a loosely bound (cytosolic) fraction, and a tightly bound (nuclear) fraction. In the absence of progestins, the functionally distinct PRs differed significantly in partitioning between the two fractions. To characterize these fractions further, we analyzed interactions of unliganded PR with chaperones by coimmunoprecipitation. We determined that PR in the cytosolic fraction associated with hsp90 and p23. In contrast, PR in the nuclear fraction consisted of complexes containing hsp90, p23, and FKBP51 as well as PR that was dimerized and highly phosphorylated. Hormone treatment significantly reduced the formation of all PR-chaperone complexes. The hsp90 inhibitor, geldanamycin, similarly blocked transcriptional activity of both functionally distinct receptors. However, the two forms of the PR differed in their ability to associate with the mouse mammary tumor virus promoter in organized chromatin. These findings provide new information about the composition and distribution of mature progesterone receptor complexes in mammary adenocarcinoma cells, and suggest that differences in receptor subcellular distribution have a significant impact on their function. These findings also reveal that transiently expressed steroid receptors may not always be processed like their endogenous counterparts.Progesterone receptor (PR) 1 functions in the development of lobular alveolar structures in the normal mammary gland (1, 2). Data from in vitro studies using cultured breast cancer cells suggest that PR exerts its effects on mammary epithelium by regulating cell cycle progression. PR positive breast cancer cells exhibit a biphasic response to progestins, initial cell division followed by long term G 1 phase growth arrest (3, 4). In mammary adenocarcinoma, PR-mediated growth regulation is frequently lost. However, loss of function through receptor deletion or receptor mutation occurs only in a subset of tumors (5). Therefore, in the majority of cases, other mechanisms must be involved in loss of PR function. A better understanding of the mechanisms by which PR function can be modulated would be beneficial to developing therapy for tumors in which PR function has been lost or altered.In vivo, steroid receptors must interact with transcriptionally inactive promoters having complex chromatin structure. Accordingly, their transcriptional activity is dependent upon a variety of proteins that modify chromatin structure, such as ATP-dependent chromatin remodelers, histone acetyltransferases, and...

BackgroundAssociations were examined between author-reported uses of reporting guidelines to prepare JNCI: Journal of the National Cancer Institute (JNCI) submissions, editorial decisions, and reviewer ratings for adherence to reporting guidelines and clarity of presentation.MethodsAt submission, authors were asked if they used reporting guidelines to prepare their manuscript and, if so, which one(s). Reviewers rated adherence to reporting guidelines and clarity of presentation. Data were gathered using a customized Editorial Manager Enterprise Analytics Report for submissions with first or final decisions that were submitted between November 1, 2015, and April 30, 2017. Manuscript types that would benefit from the use of reporting guidelines were included. All reviews were included in the analyses. Numerical values were given to each answer (yes, 1; no, 0) or reviewer rating (not applicable, 0; fair, 1; poor, 2; good, 3; very good, 4; and outstanding, 5), and scores were compared using two-sided t tests.ResultsOf 2209 submissions included in the analysis, 1144 (51.8%) indicated that at least one reporting guideline was used. The STROBE guidelines were the most common (n = 531, 24.0%). Of the 2068 (93.6%) submissions that were rejected, 1105 (50.1%) indicated using reporting guidelines and 963 (43.6%) did not (mean [SD] scores of rejected vs not rejected, 0.53 [0.50] vs 0.49 [0.50], P = .47). Of the 1033 ratings for adherence to reporting guidelines, mean (SD) scores for not rejected vs rejected submissions were 3.2 (1.61) vs 2.9 (1.57) (P = .005), and mean (SD) scores for reporting guidelines use vs no use were 3.1 (1.48) vs 2.9 (1.70) (P = .01). Of the 1036 ratings for clarity of presentation, mean (SD) scores for not rejected vs rejected submissions were 3.6 (1.00) vs 3.1 (1.08) (P < .001), whereas mean (SD) scores for reporting guidelines use vs no use were 3.3 (1.04) vs 3.3 (1.10) (P = .64).ConclusionsAmong these JNCI submissions, reporting the use of reporting guidelines was not associated with editorial decisions or with reviewer ratings for clarity of presentation. Reviewer ratings for adherence to guidelines and clarity of presentation were associated with editorial decisions after peer review, and ratings for adherence to guidelines were associated with reported use of reporting guidelines.

Retinoblastoma protein (Rb) expression has been correlated with state of differentiation, proliferation rate, and metastatic potential in breast adenocarcinomas and established cell lines. These observations, based on immunoreactivity of total Rb rather than hypophosphorylated protein, do not address the relationship between functional Rb and indicators of an aggressive transformed cellular phenotype. We hypothesized that the distribution of functional Rb and the kinetics of Rb phosphorylation would differ between cell lines representing immortalized mammary epithelium (MCF10A), differentiated nonmetastatic mammary adenocarcinoma (MCF-7), and poorly differentiated, highly metastatic mammary adenocarcinoma (MDA-MB-231) and that these differences would be informative of the cellular phenotype. Direct immunofluorescence microscopy was used to compare qualitatively the subcellular localization of total and hypophosphorylated Rb protein in synchronized and asynchronous cells. This technique was also used to quantitatively assess the amounts of hypophosphorylated Rb throughout the cell cycle in these representative cell lines. Total Rb stained more prominently than hypophosphorylated Rb in the nucleus of all asynchronous cells. Rb phosphorylation was more rapid in MCF-7 cells than in MCF10A cells, whereas Rb dephosphorylation appeared deregulated in MDA-MB-231 cells. We conclude that assessment of hypophosphorylated Rb may be more useful than assessment of total Rb for the evaluation of transformed breast adenocarcinoma phenotypes.