Somatic mutational landscape of hereditary hematopoietic malignancies caused by germline variants in RUNX1, GATA2, and DDX41

Individuals with germ line variants associated with hereditary hematopoietic malignancies (HHMs) have a highly variable risk for leukemogenesis. Gaps in our understanding of premalignant states in HHMs have hampered efforts to design effective clinical surveillance programs, provide personalized preemptive treatments, and inform appropriate counseling for patients. We used the largest known comparative international cohort of germline RUNX1, GATA2, or DDX41 variant carriers without and with hematopoietic malignancies (HMs) to identify patterns of genetic drivers that are unique to each HHM syndrome before and after leukemogenesis. These patterns included striking heterogeneity in rates of early-onset clonal hematopoiesis (CH), with a high prevalence of CH in RUNX1 and GATA2 variant carriers who did not have malignancies (carriers-without HM). We observed a paucity of CH in DDX41 carriers-without HM. In RUNX1 carriers-without HM with CH, we detected variants in TET2, PHF6, and, most frequently, BCOR. These genes were recurrently mutated in RUNX1-driven malignancies, suggesting CH is a direct precursor to malignancy in RUNX1-driven HHMs. Leukemogenesis in RUNX1 and DDX41 carriers was often driven by second hits in RUNX1 and DDX41, respectively. This study may inform the development of HHM-specific clinical trials and gene-specific approaches to clinical monitoring. For example, trials investigating the potential benefits of monitoring DDX41 carriers-without HM for low-frequency second hits in DDX41 may now be beneficial. Similarly, trials monitoring carriers-without HM with RUNX1 germ line variants for the acquisition of somatic variants in BCOR, PHF6, and TET2 and second hits in RUNX1 are warranted.

Transient neonatal hemolytic anemia due to the novel gamma globin gene mutation HBG2:C.290T>C, p.Leu97Pro (hemoglobin Wareham)

Unstable gamma globin variants can cause transient neonatal hemolytic anemia. We have identified a novel variant in a newborn who presented with jaundice and anemia requiring phototherapy and red blood cell transfusion. The patient was found to be heterozygous for the mutation HGB2:c.290T>C, p.Leu97Pro, which we have termed hemoglobin (Hb) Wareham. This substitution is expected to generate an unstable hemoglobin with increased oxygen affinity based on the homologous mutation previously described in the beta globin gene, which is termed as Hb Debrousse. The patient fully recovered by 9 months of age as expected with the transition from fetal to adult hemoglobin.

Opening the window for endothelial-to-hematopoietic transition

In this Outlook, Samarakkody and Cantor discuss the results of Howell et al., which provide new mechanistic insights into EHT and take us one step closer to generating patient-specific LT-HSCs from induced pluripotent stem cells.

Definitive long-term hematopoietic stem cells (LT-HSCs) arise during embryogenesis in a process termed endothelial-to-hematopoietic transition (EHT), in which specialized hemogenic endothelial cells (HECs) transform into hematopoietic cells. The transcription factor RUNX1 marks HECs and is essential for EHT. Ectopic RUNX1 expression in non-HECs is sufficient to convert them into HECs. However, the conversion efficiency depends on the developmental timing of expression. In this issue of Genes & Development, Howell and colleagues (pp. 1475–1489) leverage this observation to further understand how RUNX1 mediates EHT. They engineered mice that ectopically express RUNX1 in endothelial cells at different developmental time points and doses. They then performed chromatin accessibility and other analyses and correlate this with hemogenic potential. They found that RUNX1 collaborates with TGFβ signaling transcription factors to drive chromatin accessibility changes that specify HECs. They also highlight interesting parallels between EHT and endothelial-to-mesenchymal transition (EndoMT), which occurs during cardiac development. The results of Howell and colleagues provide new mechanistic insights into EHT and take us one step closer to generating patient-specific LT-HSCs from induced pluripotent stem cells.

Familial thrombocytopenia due to a complex structural variant resulting in a WAC-ANKRD26 fusion transcript

Advances in genome sequencing have resulted in the identification of the causes for numerous rare diseases. However, many cases remain unsolved with standard molecular analyses. We describe a family presenting with a phenotype resembling inherited thrombocytopenia 2 (THC2). THC2 is generally caused by single nucleotide variants that prevent silencing of ANKRD26 expression during hematopoietic differentiation. Short-read whole-exome and genome sequencing approaches were unable to identify a causal variant in this family. Using long-read whole-genome sequencing, a large complex structural variant involving a paired-duplication inversion was identified. Through functional studies, we show that this structural variant results in a pathogenic gain-of-function WAC-ANKRD26 fusion transcript. Our findings illustrate how complex structural variants that may be missed by conventional genome sequencing approaches can cause human disease.

Common variants in signaling transcription-factor-binding sites drive phenotypic variability in red blood cell traits

Genome-wide association studies identify genomic variants associated with human traits and diseases. Most trait-associated variants are located within cell-type-specific enhancers, but the molecular mechanisms governing phenotypic variation are less well understood. Here, we show that many enhancer variants associated with red blood cell (RBC) traits map to enhancers that are co-bound by lineage-specific master transcription factors (MTFs) and signaling transcription factors (STFs) responsive to extracellular signals. The majority of enhancer variants reside on STF and not MTF motifs, perturbing DNA binding by various STFs (BMP/TGF-β-directed SMADs or WNT-induced TCFs) and affecting target gene expression. Analyses of engineered human blood cells and expression quantitative trait loci verify that disrupted STF binding leads to altered gene expression. Our results propose that the majority of the RBC-trait-associated variants that reside on transcription-factor-binding sequences fall in STF target sequences, suggesting that the phenotypic variation of RBC traits could stem from altered responsiveness to extracellular stimuli.

CHD7 and Runx1 interaction provides a braking mechanism for hematopoietic differentiation

Hematopoietic stem and progenitor cell (HSPC) formation and lineage differentiation involve gene expression programs orchestrated by transcription factors and epigenetic regulators. Genetic disruption of the chromatin remodeler chromodomain-helicase-DNA-binding protein 7 (CHD7) expanded phenotypic HSPCs, erythroid, and myeloid lineages in zebrafish and mouse embryos. CHD7 acts to suppress hematopoietic differentiation. Binding motifs for RUNX and other hematopoietic transcription factors are enriched at sites occupied by CHD7, and decreased RUNX1 occupancy correlated with loss of CHD7 localization. CHD7 physically interacts with RUNX1 and suppresses RUNX1-induced expansion of HSPCs during development through modulation of RUNX1 activity. Consequently, the RUNX1:CHD7 axis provides proper timing and function of HSPCs as they emerge during hematopoietic development or mature in adults, representing a distinct and evolutionarily conserved control mechanism to ensure accurate hematopoietic lineage differentiation.

Role of RUNX Family Transcription Factors in DNA Damage Response

Cells are constantly exposed to endogenous and exogenous stresses that can result in DNA damage. In response, they have evolved complex pathways to maintain genomic integrity. RUNX family transcription factors (RUNX1, RUNX2, and RUNX3 in mammals) are master regulators of development and differentiation, and are frequently dysregulated in cancer. A growing body of research also implicates RUNX proteins as regulators of the DNA damage response, often acting in conjunction with the p53 and Fanconi anemia pathways. In this review, we discuss the functional role and mechanisms involved in RUNX factor mediated response to DNA damage and other cellular stresses. We highlight the impact of these new findings on our understanding of cancer predisposition associated with RUNX factor dysregulation and their implications for designing novel approaches to prevent cancer formation in affected individuals.

Zfp281 (ZBP-99) plays a functionally redundant role with Zfp148 (ZBP-89) during erythroid development

Erythroid maturation requires the concerted action of a core set of transcription factors. We previously identified the Krüppel-type zinc finger transcription factor Zfp148 (also called ZBP-89) as an interacting partner of the master erythroid transcription factor GATA1. Here we report the conditional knockout of Zfp148 in mice. Global loss of Zfp148 results in perinatal lethality from nonhematologic causes. Selective Zfp148 loss within the hematopoietic system results in a mild microcytic and hypochromic anemia, mildly impaired erythroid maturation, and delayed recovery from phenylhydrazine-induced hemolysis. Based on the mild erythroid phenotype of these mice compared with GATA1-deficient mice, we hypothesized that additional factor(s) may complement Zfp148 function during erythropoiesis. We show that Zfp281 (also called ZBP-99), another member of the Zfp148 transcription factor family, is highly expressed in murine and human erythroid cells. Zfp281 knockdown by itself results in partial erythroid defects. However, combined deficiency of Zfp148 and Zfp281 causes a marked erythroid maturation block. Zfp281 physically associates with GATA1, occupies many common chromatin sites with GATA1 and Zfp148, and regulates a common set of genes required for erythroid cell differentiation. These findings uncover a previously unknown role for Zfp281 in erythroid development and suggest that it functionally overlaps with that of Zfp148 during erythropoiesis.

Bone Marrow Morphology Associated With Germline RUNX1 Mutations in Patients With Familial Platelet Disorder With Associated Myeloid Malignancy

Germline mutations in RUNX1 result in autosomal dominant familial platelet disorder with associated myeloid malignancy (FPDMM). To characterize the hematopathologic features associated with a germline RUNX1 mutation, we reviewed a total of 42 bone marrow aspirates from 14 FPDMM patients, including 24 cases with no cytogenetic clonal abnormalities, and 18 with clonal karyotypes or leukemia. We found that all aspirate smears had ≥10% atypical megakaryocytes, predominantly characterized by small forms with hypolobated and eccentric nuclei, and forms with high nuclear-to-cytoplasmic ratios. Core biopsies showed variable cellularity and variable numbers of megakaryocytes with similar features to those in the aspirates. Granulocytic and/or erythroid dysplasia (≥10% cells per lineage) were present infrequently. Megakaryocytes with separate nuclear lobes were increased in patients with myelodysplastic syndrome (MDS) and acute leukemia. Comparison to an immune thrombocytopenic purpura cohort confirms increased megakaryocytes with hypolobated eccentric nuclei in FPDMM patients. As such, patients with FPDMM often have atypical megakaryocytes with small hypolobated and eccentric nuclei even in the absence of clonal cytogenetic abnormalities; these findings are related to the underlying RUNX1 germline mutation and not diagnostic of MDS. Isolated megakaryocytic dysplasia in patients with unexplained thrombocytopenia should raise the possibility of an underlying germline RUNX1 mutation.

A home-based mentored vegetable gardening intervention demonstrates feasibility and improvements in physical activity and performance among breast cancer survivors

BACKGROUND

The current study assessed the feasibility of a mentored home-based vegetable gardening intervention and examined changes in health-related outcomes among breast cancer survivors (BCS).

METHODS

BCS were randomized to either a year-long vegetable gardening intervention to begin immediately or a wait-list control. Master Gardeners mentored participants in planning, planting, and maintaining 3 seasonal gardens over the course of 1 year. Participant accrual, retention, and satisfaction rates of ≥80% served as feasibility (primary outcome) benchmarks. Secondary outcomes (ie, vegetable consumption, physical activity, performance and function, anthropometrics, biomarkers, and health-related quality of life) were collected at baseline and post-intervention (1-year follow-up) using subjective and objective measures.

RESULTS

The trial surpassed all feasibility benchmarks at 82% of targeted accrual, 95% retention, and 100% satisfaction (ie, experience ratings of "good to excellent" and willingness to "do it again"). Compared with the controls, intervention participants reported significantly greater improvements in moderate physical activity (+14 vs -17 minutes/week) and demonstrated improvements in the 2-Minute Step Test (+22 vs + 10 steps), and Arm Curl (+2.7 vs + 0.1 repetitions) (P values < .05). A trend toward improved vegetable consumption was observed (+0.9 vs + 0.2 servings/day; P = .06). Approximately 86% of participants were continuing to garden at the 2-year follow-up.

CONCLUSIONS

The results of the current study suggest that a mentored, home-based vegetable gardening intervention is feasible and offers an integrative and durable approach with which to improve health behaviors and outcomes among BCS. Harvest for Health led to the establishment of a group of trained Master Gardeners and gave rise to local and global community-based programs. Larger studies are needed to confirm the results presented herein and to define applicability across broader populations of survivors.

Assessing the Feasibility of a Mentored Home-Based Vegetable Gardening Intervention among Breast Cancer Survivors in the Deep South

To assess the feasibility of a mentored home-based vegetable gardening intervention among Breast Cancer Survivors (BCS) residing in the Birmingham, Alabama metropolitan area. Methods: Using a wait-list control design, BCS were randomized to either a year-long vegetable gardening intervention or a wait-list control. Intervention participants were provided with necessary supplies and paired with a Master Gardener from the Cooperative Extension. Master Gardeners mentored participants in planning, planting, and maintaining 3 seasonal gardens over 12 months, conducted monthly home-visits, and checked in bi-weekly via telephone or email. Feasibility assessment criteria consisted of participant accrual, retention, and satisfaction rates of ≥80%. Target participant accrual was 100. Participant satisfaction data were collected after study completion via structured telephone debriefing. Descriptive statistics were conducted using SPSS V24. Results: 82 BCS (Mage = 60 (39–84); Msurvivorship = 5 years (0.5–23); Mco-morbidities = 3.5 (0–12); ≥2 functional limitations = 86.6%; Caucasian = 73.2%; African-American = 26.8%) enrolled (82% accrual). Of these, four did not complete the study (2 refused to be wait-listed due to not wanting to wait to garden, 1 withdrew due to family obligations, and 1 was lost to follow-up), resulting in an retention rate of 95% over a 1-year period. All BCS who completed the intervention (n = 42) rated their Harvest for Health experience as “Good to Excellent”, reported that they would “do it again”, and planned to “continue to garden.” When asked to rate, on a scale of 1–10 (1 = not at all and 10 = very much), the influence of gardening on motivating behavior change, BCS reported that gardening motivated them to… “eat a healthier diet” (M = 8.38; SD = 2.07), “eat more vegetables” (M = 8.43; SD = 2.08), and “be more physically active” (M = 7.5; SD = 2.73). Conclusions: The vegetable gardening intervention proved to be feasible and provided new knowledge about the influence of gardening on motivating behavior change among BCS. Findings suggest that a mentored home-based vegetable gardening may offer an integrative approach to improve diet, vegetable consumption, and physical activity among BCS. Larger, future studies are warranted.

Pilot Randomized Controlled Trial of a Home Vegetable Gardening Intervention among Older Cancer Survivors Shows Feasibility, Satisfaction, and Promise in Improving Vegetable and Fruit Consumption, Reassurance of Worth, and the Trajectory of Central Adiposity

BACKGROUND

Holistic approaches are sought to improve lifestyle behaviors and health of cancer survivors long term.

OBJECTIVE

Our aim was to explore whether a home-based vegetable gardening intervention is feasible and whether it improves diet and other health-related outcomes among older cancer survivors.

DESIGN

We conducted a feasibility trial in which cancer survivors were randomized to receive a year-long gardening intervention immediately or to a wait-list control arm. Home visits at baseline and 1 year assessed physical performance, anthropometric indices, behavioral and psychosocial outcomes, and biomarkers.

PARTICIPANTS/SETTING

Participants included 46 older (aged 60+ years) survivors of locoregionally staged cancers across Alabama from 2014 to 2016. Forty-two completed 1-year follow-up.

INTERVENTION

Cooperative extension master gardeners delivered guidance to establish three seasonal vegetable gardens at survivors' homes. Plants, seeds, and gardening supplies were provided.

OUTCOMES

Primary outcomes were feasibility targets of 80% accrual and retention, and an absence of serious adverse events; other outcomes were secondary and explored potential benefits.

STATISTICAL ANALYSES

Baseline to follow-up changes were assessed within and between arms using paired t, McNemar's, and χ² tests.

RESULTS

This trial proved to be safe and demonstrated 91.3% retention; 70% of intervention participants rated their experience as "excellent," and 85% would "do it again." Data suggest significantly increased reassurance of worth (+0.49 vs -0.45) and attenuated increases in waist circumference (+2.30 cm vs +7.96 cm) in the gardening vs control arms (P=0.02). Vegetable and fruit consumption increased by approximately 1 serving/day within the gardening arm from baseline to follow-up (mean [standard error]=1.34 [1.2] to 2.25 [1.9] servings/day; P=0.02)] compared to controls (1.22 [1.1] to 1.12 [0.7]; P=0.77; between-arm P=0.06).

CONCLUSIONS

The home vegetable gardening intervention among older cancer survivors was feasible and suggested improvements in vegetable and fruit consumption and reassurance of worth; data also suggest attenuated increases in waist circumference. Continued study of vegetable gardening interventions is warranted to improve health, health behaviors, and well-being of older cancer survivors.

Abstract 26: RUNX1 as a transcriptional target of activated Shp2 (PTPN11) in juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasm of young children. The only current curative treatment is bone marrow transplantation. Yet even with this aggressive therapy, ~50% of children still die from their disease. Somatic mutations leading to constitutive activation of the non-receptor tyrosine phosphatase Shp2 (also called PTPN11) or of RAS signaling occur in &gt;70% of JMML cases. However, the transcription factors that act downstream of these aberrant signaling events have not been identified. We recently showed that the key myelomonocytic transcription factor RUNX1 is inactivated by src-family kinase-mediated tyrosine phosphorylation (Huang et al. Genes Dev 2012;26:1587-1601). Moreover, we demonstrated that Shp2 directly dephosphorylates RUNX1 leading to RUNX1 relative activation. We now show that overexpression of a mutant RUNX1 that is resistant to SFK-mediated tyrosine phosphorylation (RUNX1Y260F, Y375F, Y378F, Y379F, Y386F—“RUNX1-5F”), mimicking constitutive dephosphorylation, causes cytokine-independent growth of Ba/F3 cells. Overexpression of RUNX15F in murine Lin- Sca-1+ c-kit+, (LSK) bone marrow cells leads to a dramatic expansion of Gr1+, Mac-1+ cells, and CFU-M/CFU-GM in vitro and in vivo. These effects are not seen when wild-type RUNX1 or RUNX1Y260D, Y375D, Y378D, Y379FD,Y386FD (“RUNX1-5D”; mimicking constitutive RUNX1 tyrosine phosphorylation) are overexpressed. The RUNX1-5F expressing cells have increased proliferation (BrdU incorporation), decreased apoptosis, and reduced cytokine dependence. Flow sorted Gr1+Mac1+ cells from the RUNX1-5F transduced cultures express higher levels of the direct RUNX1 target genes PU.1 and cyclin D1. RUNX1 haploinsufficiency in a Shp2 LSL-D61Y conditional knock-in JMML mouse model reduces the disease phenotype, and treatment with the RUNX1 inhibitor Ro5-3335 ameliorates cytokine-independent in vitro bone marrow colony growth from this mouse model. Gene expression analysis of CD34+ cells from JMML patients versus controls combined with RUNX1 CD34+ cell ChIP-seq data shows significant enrichment for RUNX1 chromatin occupancy at differentially expressed genes compared to all expressed genes. To test whether RUNX1 is required for the myelomonocytic hyperproliferation in JMML, CD34+ peripheral blood cells from a patient with JMML due to an activating Shp2 mutation (Shp2E78G) were lentivirally transduced with doxycylcine-inducible RUNX1-5D or RUNX1-5F expression constructs and cultured under myeloid growth conditions. Upon doxycycline induction, the RUNX1-5D overexpressing cells (resistant to Shp2) exhibited at 32% reduction in BrdU incorporation. In contrast, the control RUNX1-5F expressing cells had no significant reduction in proliferation. RUNX1 is also by direct ERK mediated phosphorylation (which is downstream of RAS/MEK). We propose that RUNX1 activation is an important common downstream consequence of both activated Shp2 and RAS signaling in the pathogenesis of JMML, and that RUNX1 inhibition may represent a novel therapeutic approach for this disorder.

Citation Format: Elisa Dorantes-Acosta, Hui Huang, Sara P. Garcia, Elliot Stieglitz, Mignon Loh, Guo-Cheng Yuan, Alan B. Cantor. RUNX1 as a transcriptional target of activated Shp2 (PTPN11) in juvenile myelomonocytic leukemia [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr 26.

Erythropoietin signaling regulates heme biosynthesis

Heme is required for survival of all cells, and in most eukaryotes, is produced through a series of eight enzymatic reactions. Although heme production is critical for many cellular processes, how it is coupled to cellular differentiation is unknown. Here, using zebrafish, murine, and human models, we show that erythropoietin (EPO) signaling, together with the GATA1 transcriptional target, AKAP10, regulates heme biosynthesis during erythropoiesis at the outer mitochondrial membrane. This integrated pathway culminates with the direct phosphorylation of the crucial heme biosynthetic enzyme, ferrochelatase (FECH) by protein kinase A (PKA). Biochemical, pharmacological, and genetic inhibition of this signaling pathway result in a block in hemoglobin production and concomitant intracellular accumulation of protoporphyrin intermediates. Broadly, our results implicate aberrant PKA signaling in the pathogenesis of hematologic diseases. We propose a unifying model in which the erythroid transcriptional program works in concert with post-translational mechanisms to regulate heme metabolism during normal development.

DOI:http://dx.doi.org/10.7554/eLife.24767.001

Heme is an iron-containing compound that is important for all living things, from bacteria to humans. Our red blood cells use heme to carry oxygen and deliver it throughout the body. The amount of heme that is produced must be tightly regulated. Too little or too much heme in a person’s red blood cells can lead to blood-related diseases such as anemia and porphyria. Yet, while scientists knew the enzymes needed to make heme, they did not know how these enzymes were controlled.

Now, Chung et al. show that an important signaling molecule called erythropoietin controls how much heme is produced when red blood cells are made. The experiments used a combination of red blood cells from humans and mice as well as zebrafish, which are useful model organisms because their blood develops in a similar way to humans. When Chung et al. inhibited components of erythropoietin signaling, heme production was blocked too and the red blood cells could not work properly.

These new findings pave the way to look at human patients with blood-related disorders to determine if they have defects in the erythropoietin signaling cascade. In the future, this avenue of research might lead to better treatments for a variety of blood diseases in humans.

DOI:http://dx.doi.org/10.7554/eLife.24767.002

Detailed methods of two home-based vegetable gardening intervention trials to improve diet, physical activity, and quality of life in two different populations of cancer survivors

BACKGROUND

Cancer survivors suffer from long-term adverse effects that reduce health-related quality of life (QOL) and physical functioning, creating an urgent need to develop effective, durable, and disseminable interventions. Harvest for Health, a home-based vegetable gardening intervention, holds promise for these domains.

METHODS

This report describes the methods and recruitment experiences from two randomized controlled feasibility trials that employ a waitlist-controlled design. Delivered in partnership with Cooperative Extension Master Gardeners, this intervention provides one-on-one mentorship of cancer survivors in planning and maintaining three seasonal vegetable gardens over 12months. The primary aim is to determine intervention feasibility and acceptability; secondary aims are to explore effects on objective and subjective measures of diet, physical activity and function, and QOL and examine participant factors associated with potential effects. One trial is conducted exclusively among 82 female breast cancer survivors residing in the Birmingham, AL metropolitan area (BBCS); another broadly throughout Alabama among 46 older cancer survivors aged >60 (ASCS).

RESULTS

Response rates were 32.6% (BBCS) and 52.3% (ASCS). Both trials exceeded 80% of their accrual target. Leading reasons for ineligibility were removal of >10 lymph nodes (lymphedema risk factor), lack of physician approval, and unwillingness to be randomized to the waitlist.

CONCLUSION

To date, recruitment and implementation of Harvest for Health appears feasible.

DISCUSSION

Although both studies encountered recruitment challenges, lessons learned can inform future larger-scale studies. Vegetable gardening interventions are of interest to cancer survivors and may provide opportunities to gain life skills leading to improvements in overall health and QOL.

Runx1 Phosphorylation by Src Increases Trans-activation via Augmented Stability, Reduced Histone Deacetylase (HDAC) Binding, and Increased DNA Affinity, and Activated Runx1 Favors Granulopoiesis

Src phosphorylates Runx1 on one central and four C-terminal tyrosines. We find that activated Src synergizes with Runx1 to activate a Runx1 luciferase reporter. Mutation of the four Runx1 C-terminal tyrosines to aspartate or glutamate to mimic phosphorylation increases trans-activation of the reporter in 293T cells and allows induction of Cebpa or Pu.1 mRNAs in 32Dcl3 myeloid cells, whereas mutation of these residues to phenylalanine to prevent phosphorylation obviates these effects. Three mechanisms contribute to increased Runx1 activity upon tyrosine modification as follows: increased stability, reduced histone deacetylase (HDAC) interaction, and increased DNA binding. Mutation of the five modified Runx1 tyrosines to aspartate markedly reduced co-immunoprecipitation with HDAC1 and HDAC3, markedly increased stability in cycloheximide or in the presence of co-expressed Cdh1, an E3 ubiquitin ligase coactivator, with reduced ubiquitination, and allowed DNA-binding in gel shift assay similar to wild-type Runx1. In contrast, mutation of these residues to phenylalanine modestly increased HDAC interaction, modestly reduced stability, and markedly reduced DNA binding in gel shift assays and as assessed by chromatin immunoprecipitation with the -14-kb Pu.1 or +37-kb Cebpa enhancers after stable expression in 32Dcl3 cells. Affinity for CBFβ, the Runx1 DNA-binding partner, was not affected by these tyrosine modifications, and in vitro translated CBFβ markedly increased DNA affinity of both the translated phenylalanine and aspartate Runx1 variants. Finally, further supporting a positive role for Runx1 tyrosine phosphorylation during granulopoiesis, mutation of the five Src-modified residues to aspartate but not phenylalanine allows Runx1 to increase Cebpa and granulocyte colony formation by Runx1-deleted murine marrow.

The mTORC1/4E-BP pathway coordinates hemoglobin production with L-leucine availability

In multicellular organisms, the mechanisms by which diverse cell types acquire distinct amino acids and how cellular function adapts to their availability are fundamental questions in biology. We found that increased neutral essential amino acid (NEAA) uptake was a critical component of erythropoiesis. As red blood cells matured, expression of the amino acid transporter gene Lat3 increased, which increased NEAA import. Inadequate NEAA uptake by pharmacologic inhibition or RNAi-mediated knockdown of LAT3 triggered a specific reduction in hemoglobin production in zebrafish embryos and murine erythroid cells through the mTORC1 (mammalian target of rapamycin complex 1)/4E-BP (eukaryotic translation initiation factor 4E-binding protein) pathway. CRISPR-mediated deletion of members of the 4E-BP family in murine erythroid cells rendered them resistant to mTORC1 and LAT3 inhibition and restored hemoglobin production. These results identify a developmental role for LAT3 in red blood cells and demonstrate that mTORC1 serves as a homeostatic sensor that couples hemoglobin production at the translational level to sufficient uptake of NEAAs, particularly L-leucine.

TMEM14C is required for erythroid mitochondrial heme metabolism

The transport and intracellular trafficking of heme biosynthesis intermediates are crucial for hemoglobin production, which is a critical process in developing red cells. Here, we profiled gene expression in terminally differentiating murine fetal liver-derived erythroid cells to identify regulators of heme metabolism. We determined that TMEM14C, an inner mitochondrial membrane protein that is enriched in vertebrate hematopoietic tissues, is essential for erythropoiesis and heme synthesis in vivo and in cultured erythroid cells. In mice, TMEM14C deficiency resulted in porphyrin accumulation in the fetal liver, erythroid maturation arrest, and embryonic lethality due to profound anemia. Protoporphyrin IX synthesis in TMEM14C-deficient erythroid cells was blocked, leading to an accumulation of porphyrin precursors. The heme synthesis defect in TMEM14C-deficient cells was ameliorated with a protoporphyrin IX analog, indicating that TMEM14C primarily functions in the terminal steps of the heme synthesis pathway. Together, our data demonstrate that TMEM14C facilitates the import of protoporphyrinogen IX into the mitochondrial matrix for heme synthesis and subsequent hemoglobin production. Furthermore, the identification of TMEM14C as a protoporphyrinogen IX importer provides a genetic tool for further exploring erythropoiesis and congenital anemias.

Developmental differences in IFN signaling affect GATA1s-induced megakaryocyte hyperproliferation

About 10% of Down syndrome (DS) infants are born with a transient myeloproliferative disorder (DS-TMD) that spontaneously resolves within the first few months of life. About 20%-30% of these infants subsequently develop acute megakaryoblastic leukemia (DS-AMKL). Somatic mutations leading to the exclusive production of a short GATA1 isoform (GATA1s) occur in all cases of DS-TMD and DS-AMKL. Mice engineered to exclusively produce GATA1s have marked megakaryocytic progenitor (MkP) hyperproliferation during early fetal liver (FL) hematopoiesis, but not during postnatal BM hematopoiesis, mirroring the spontaneous resolution of DS-TMD. The mechanisms that underlie these developmental stage-specific effects are incompletely understood. Here, we report a striking upregulation of type I IFN-responsive gene expression in prospectively isolated mouse BM- versus FL-derived MkPs. Exogenous IFN-α markedly reduced the hyperproliferation FL-derived MkPs of GATA1s mice in vitro. Conversely, deletion of the α/β IFN receptor 1 (Ifnar1) gene or injection of neutralizing IFN-α/β antibodies increased the proliferation of BM-derived MkPs of GATA1s mice beyond the initial postnatal period. We also found that these differences existed in human FL versus BM megakaryocytes and that primary DS-TMD cells expressed type I IFN-responsive genes. We propose that increased type I IFN signaling contributes to the developmental stage-specific effects of GATA1s and possibly the spontaneous resolution of DS-TMD.

Prognostic relevance of cytochrome C oxidase in primary glioblastoma multiforme

Patients with primary glioblastoma multiforme (GBM) have one of the lowest overall survival rates among cancer patients, and reliable biomarkers are necessary to predict patient outcome. Cytochrome c oxidase (CcO) promotes the switch from glycolytic to OXPHOS metabolism, and increased CcO activity in tumors has been associated with tumor progression after chemotherapy failure. Thus, we investigated the relationship between tumor CcO activity and the survival of patients diagnosed with primary GBM. A total of 84 patients with grade IV glioma were evaluated in this retrospective cohort study. Cumulative survival was calculated by the Kaplan-Meier method and analyzed by the log-rank test, and univariate and multivariate analyses were performed with the Cox regression model. Mitochondrial CcO activity was determined by spectrophotometrically measuring the oxidation of cytochrome c. High CcO activity was detected in a subset of glioma tumors (∼30%), and was an independent prognostic factor for shorter progression-free survival and overall survival [P = 0.0087 by the log-rank test, hazard ratio = 3.57 for progression-free survival; P<0.001 by the log-rank test, hazard ratio = 10.75 for overall survival]. The median survival time for patients with low tumor CcO activity was 14.3 months, compared with 6.3 months for patients with high tumor CcO activity. High CcO activity occurs in a significant subset of high-grade glioma patients and is an independent predictor of poor outcome. Thus, CcO activity may serve as a useful molecular marker for the categorization and targeted therapy of GBMs.

A Src family kinase-Shp2 axis controls RUNX1 activity in megakaryocyte and T-lymphocyte differentiation

Hematopoietic development occurs in complex microenvironments and is influenced by key signaling events. Yet how these pathways communicate with master hematopoietic transcription factors to coordinate differentiation remains incompletely understood. The transcription factor RUNX1 plays essential roles in definitive hematopoietic stem cell (HSC) ontogeny, HSC maintenance, megakaryocyte (Mk) maturation, and lymphocyte differentiation. It is also the most frequent target of genetic alterations in human leukemia. Here, we report that RUNX1 is phosphorylated by Src family kinases (SFKs) and that this occurs on multiple tyrosine residues located within its negative regulatory DNA-binding and autoinhibitory domains. Retroviral transduction, chemical inhibitor, and genetic studies demonstrate a negative regulatory role of tyrosine phosphorylation on RUNX1 activity in Mk and CD8 T-cell differentiation. We also demonstrate that the nonreceptor tyrosine phosphatase Shp2 binds directly to RUNX1 and contributes to its dephosphorylation. Last, we show that RUNX1 tyrosine phosphorylation correlates with reduced GATA1 and enhanced SWI/SNF interactions. These findings link SFK and Shp2 signaling pathways to the regulation of RUNX1 activity in hematopoiesis via control of RUNX1 multiprotein complex assembly.

Direct recruitment of polycomb repressive complex 1 to chromatin by core binding transcription factors

Polycomb repressive complexes (PRCs) play key roles in developmental epigenetic regulation. Yet the mechanisms that target PRCs to specific loci in mammalian cells remain incompletely understood. In this study we show that Bmi1, a core component of Polycomb Repressive Complex 1 (PRC1), binds directly to the Runx1/CBFβ transcription factor complex. Genome-wide studies in megakaryocytic cells demonstrate significant chromatin occupancy overlap between the PRC1 core component Ring1b and Runx1/CBFβ and functional regulation of a considerable fraction of commonly bound genes. Bmi1/Ring1b and Runx1/CBFβ deficiencies generate partial phenocopies of one another in vivo. We also show that Ring1b occupies key Runx1 binding sites in primary murine thymocytes and that this occurs via PRC2-independent mechanisms. Genetic depletion of Runx1 results in reduced Ring1b binding at these sites in vivo. These findings provide evidence for site-specific PRC1 chromatin recruitment by core binding transcription factors in mammalian cells.

Megakaryopoiesis and thrombopoiesis: an update on cytokines and lineage surface markers

Megakaryopoiesis is the process by which mature megakaryocytes (MKs) develop from hematopoietic stem cells (HSCs). The biological function of MKs is to produce platelets, which play critical roles in hemostasis and contribute to angiogenesis and wound healing. The generation of platelets from MKs is termed thrombopoiesis. The cytokine thrombopoietin (TPO) is the major regulator of megakaryopoiesis and thrombopoiesis. It binds to its surface receptor, c-Mpl, and acts through multiple downstream signaling pathways, including the PI-3 kinase-Akt, MAPK, and ERK1/ERK2 pathways. However, non-TPO pathways, such as the SDF1/CXCR4 axis, Notch signaling, src family kinases, integrin signaling, and Platelet Factor 4/low-density lipoprotein receptor-related protein 1, have more recently been recognized to influence megakaryopoiesis and thrombopoiesis in vitro and in vivo. In this chapter, we review megakaryopoiesis and thrombopoiesis with emphasis on cell surface marker changes during their differentiation from HSCs, and the classical cytokines that affect these developmental stages. We also discuss non-TPO regulators and their effects on in vitro culture systems.

Role of ZBP-89 in human globin gene regulation and erythroid differentiation

The molecular mechanisms underlying erythroid-specific gene regulation remain incompletely understood. Closely spaced binding sites for GATA, NF-E2/maf, and CACCC interacting transcription factors play functionally important roles in globin and other erythroid-specific gene expression. We and others recently identified the CACCC-binding transcription factor ZBP-89 as a novel GATA-1 and NF-E2/mafK interacting partner. Here, we examined the role of ZBP-89 in human globin gene regulation and erythroid maturation using a primary CD34(+) cell ex vivo differentiation system. We show that ZBP-89 protein levels rise dramatically during human erythroid differentiation and that ZBP-89 occupies key cis-regulatory elements within the globin and other erythroid gene loci. ZBP-89 binding correlates strongly with RNA Pol II occupancy, active histone marks, and high-level gene expression. ZBP-89 physically associates with the histone acetyltransferases p300 and Gcn5/Trrap, and occupies common sites with Gcn5 within the human globin loci. Lentiviral short hairpin RNAs knockdown of ZBP-89 results in reduced Gcn5 occupancy, decreased acetylated histone 3 levels, lower globin and erythroid-specific gene expression, and impaired erythroid maturation. Addition of the histone deacetylase inhibitor valproic acid partially reverses the reduced globin gene expression. These findings reveal an activating role for ZBP-89 in human globin gene regulation and erythroid differentiation.

Abstract C123: Pharmacogenomic analysis of patients newly diagnosed with glioblastoma multiforme treated with capecitabine concurrent with radiation therapy: Gene expression profiles associated with clinical outcome

Purpose: Previous pharmacogenomic studies of glioblastoma multiforme (GBM) tissues and xenograft models suggested that concurrent administration of capecitabine and radiation could be an effective new treatment modality for GBM. In the current study, toxicity and outcome to this treatment regimen was clinically investigated and the expression of genes previously associated with capecitabine and radiotherapy response were assessed with the ultimate goal of exploring gene expression-based predictor models of patient outcome.

Methods: Eighteen patients diagnosed with primary GBM received capecitabine at 625 mg/m2 BID (escalating by 25%) concurrently with irradiation (60 Gy in 30 fractions) for 6 weeks followed by 4 weeks of capecitabine only. Following a one-week hiatus, patients received maintenance capecitabine (1250 mg/m2 BID) for 14 days every 3 weeks until progression or unacceptable toxicity. Patient time-to-progression (TTP) and overall survival (OS) were assessed using the Kaplan and Meier method. Expression analysis of 94 genes involved in capecitabine metabolism and radiation response was performed on resected and biopsied GBM tissues obtained prior to therapy. The relationship between gene expression and outcome (TTP and OS) was investigated using a semi-supervised statistical approach incorporating univariate Cox proportional hazards regression, semi-supervised principle component analysis (SSPCA), and class prediction modeling.

Results: The maximum tolerated dose of capecitabine was identified as 625 mg/m2 BID, with no unexpected toxicities observed. Median patient TTP and OS were 247 and 367 days respectively. Cox regression analysis demonstrated a significant association between the expression of 24 genes and TTP and/or OS (p&lt;0.025). Subsequent SSPCA identified two GBM patient populations that were significantly different in both TTP (p = 0.005) and OS (p = 0.015), which were subsequently designated as poor and good outcome subgroups. Class prediction modeling of the patient subgroups identified an 8 gene expression-based predictor model (RAD54B, FRAP1, DCTD, APEX2, TK1, RRM2, SLC29A1, and ERCC6) that accurately classified all patients as either good or poor outcome.

Conclusions: Capecitabine and concurrent radiation for newly diagnosed GBM appears safe and well tolerated without unexpected toxicities. Assessment of patient TTP and OS suggests capecitabine radiotherapy is comparable to the currently accepted standard of care of concurrent temozolomide radiotherapy and warrants further clinical investigation. Importantly, these exploratory studies identified a gene expression profile predictive of patient outcome that may be useful in the future stratification of GBM patients for capecitabine therapy.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C123.

Insights into GATA-1-mediated gene activation versus repression via genome-wide chromatin occupancy analysis

The transcription factor GATA-1 is required for terminal erythroid maturation and functions as an activator or repressor depending on gene context. Yet its in vivo site selectivity and ability to distinguish between activated versus repressed genes remain incompletely understood. In this study, we performed GATA-1 ChIP-seq in erythroid cells and compared it to GATA-1-induced gene expression changes. Bound and differentially expressed genes contain a greater number of GATA-binding motifs, a higher frequency of palindromic GATA sites, and closer occupancy to the transcriptional start site versus nondifferentially expressed genes. Moreover, we show that the transcription factor Zbtb7a occupies GATA-1-bound regions of some direct GATA-1 target genes, that the presence of SCL/TAL1 helps distinguish transcriptional activation versus repression, and that polycomb repressive complex 2 (PRC2) is involved in epigenetic silencing of a subset of GATA-1-repressed genes. These data provide insights into GATA-1-mediated gene regulation in vivo.

The role and regulation of friend of GATA-1 (FOG-1) during blood development in the zebrafish

The nuclear protein FOG-1 binds transcription factor GATA-1 to facilitate erythroid and megakaryocytic maturation. However, little is known about the function of FOG-1 during myeloid and lymphoid development or how FOG-1 expression is regulated in any tissue. We used in situ hybridization, gain- and loss-of-function studies in zebrafish to address these problems. Zebrafish FOG-1 is expressed in early hematopoietic cells, as well as heart, viscera, and paraspinal neurons, suggesting that it has multifaceted functions in organogenesis. We found that FOG-1 is dispensable for endoderm specification but is required for endoderm patterning affecting the expression of late-stage T-cell markers, independent of GATA-1. The suppression of FOG-1, in the presence of normal GATA-1 levels, induces severe anemia and thrombocytopenia and expands myeloid-progenitor cells, indicating that FOG-1 is required during erythroid/myeloid commitment. To functionally interrogate whether GATA-1 regulates FOG-1 in vivo, we used bioinformatics combined with transgenic assays. Thus, we identified 2 cis-regulatory elements that control the tissue-specific gene expression of FOG-1. One of these enhancers contains functional GATA-binding sites, indicating the potential for a regulatory loop in which GATA factors control the expression of their partner protein FOG-1.

Common features of megakaryocytes and hematopoietic stem cells: what's the connection?

Megakaryocytes (Mks) are rare polyploid bone marrow cells whose function is to produce blood platelets. Since the purification and cloning of the major Mk cytokine, thrombopoietin, in 1994, considerable progress has been made in understanding the biology of Mk development. Remarkably, these advances have revealed a number of key features of Mks that are shared with hematopoietic stem cells (HSCs), such as common surface receptors, lineage-specific transcription factors, and specialized signaling pathways. Why there should be such a close connection between these two cell types remains unclear. In this Prospect article, we summarize the data supporting these shared features and speculate on possible teleological bases. In particular, we focus on common links involving developmental hierarchy, endothelial cells, and bone marrow niche interactions. This discussion highlights new data showing close ontologic relationship between HSCs and specialized "hemogenic" endothelial cells during development, and functional overlap between Mks/platelets and endothelial cells. Overall, these findings may be of relevance in the development of techniques for HSC ex vivo culture and/or possible generation of HSCs via somatic cell reprogramming.

Differentiation-dependent interactions between RUNX-1 and FLI-1 during megakaryocyte development

The transcription factor RUNX-1 plays a key role in megakaryocyte differentiation and is mutated in cases of myelodysplastic syndrome and leukemia. In this study, we purified RUNX-1-containing multiprotein complexes from phorbol ester-induced L8057 murine megakaryoblastic cells and identified the ets transcription factor FLI-1 as a novel in vivo-associated factor. The interaction occurs via direct protein-protein interactions and results in synergistic transcriptional activation of the c-mpl promoter. Interestingly, the interaction fails to occur in uninduced cells. Gel filtration chromatography confirms the differentiation-dependent binding and shows that it correlates with the assembly of a complex also containing the key megakaryocyte transcription factors GATA-1 and Friend of GATA-1 (FOG-1). Phosphorylation analysis of FLI-1 with uninduced versus induced L8057 cells suggests the loss of phosphorylation at serine 10 in the induced state. Substitution of Ser10 with the phosphorylation mimic aspartic acid selectively impairs RUNX-1 binding, abrogates transcriptional synergy with RUNX-1, and dominantly inhibits primary fetal liver megakaryocyte differentiation in vitro. Conversely, substitution with alanine, which blocks phosphorylation, augments differentiation of primary megakaryocytes. We propose that dephosphorylation of FLI-1 is a key event in the transcriptional regulation of megakaryocyte maturation. These findings have implications for other cell types where interactions between runx and ets family proteins occur.

Tandem affinity purification of protein complexes in mouse embryonic stem cells using in vivo biotinylation

In dissecting the pluripotent state in mouse embryonic stem (ES) cells, we have employed in vivo biotinylation of critical transcription factors for streptavidin affinity purification of protein complexes and constructed a protein-protein interaction network. This has facilitated discovery of novel pluripotency factors and a better understanding of stem cell pluripotency. Here we describe detailed procedures for in vivo biotinylation system setup in mouse ES cells, and affinity purification of multi-protein complexes using in vivo biotinylation. In addition, we present a protocol employing SDS-PAGE fractionation to reduce sample complexity prior to submission for mass spectrometry (MS) protein identification.

TLX1 (HOX11) immortalization of embryonic stem cell-derived and primary murine hematopoietic progenitors

The ability to generate genetically engineered cell lines is of great experimental value. They provide a renewable source of material that may be suitable for biochemical analyses, chromatin immunoprecipitation assays, structure-function studies, gene function assignment, and transcription factor target gene identification. This unit describes protocols for TLX1 (HOX11)-mediated immortalization of murine hematopoietic progenitors derived from in vitro differentiated murine embryonic stem cells, or from primary mouse fetal liver or bone marrow. A wide variety of hematopoietic cell types have been immortalized using these procedures including erythroid, megakaryocytic, monocytic, myelocytic, and multipotential cell types. These lines are typically cytokine dependent for their survival and growth.

Human Fetal Hemoglobin Expression Is Regulated by the Developmental Stage-Specific Repressor BCL11A

Differences in the amount of fetal hemoglobin (HbF) that persists into adulthood affect the severity of sickle cell disease and the β-thalassemia syndromes. Genetic association studies have identified sequence variants in the gene BCL11A that influence HbF levels. Here, we examine BCL11A as a potential regulator of HbF expression. The high-HbF BCL11A genotype is associated with reduced BCL11A expression. Moreover, abundant expression of full-length forms of BCL11A is developmentally restricted to adult erythroid cells. Down-regulation of BCL11A expression in primary adult erythroid cells leads to robust HbF expression. Consistent with a direct role of BCL11A in globin gene regulation, we find that BCL11A occupies several discrete sites in the β-globin gene cluster. BCL11A emerges as a therapeutic target for reactivation of HbF in β-hemoglobin disorders.

Antagonism of FOG-1 and GATA factors in fate choice for the mast cell lineage

The zinc finger transcription factor GATA-1 requires direct physical interaction with the cofactor friend of GATA-1 (FOG-1) for its essential role in erythroid and megakaryocytic development. We show that in the mast cell lineage, GATA-1 functions completely independent of FOG proteins. Moreover, we demonstrate that FOG-1 antagonizes the fate choice of multipotential progenitor cells for the mast cell lineage, and that its down-regulation is a prerequisite for mast cell development. Remarkably, ectopic expression of FOG-1 in committed mast cell progenitors redirects them into the erythroid, megakaryocytic, and granulocytic lineages. These lineage switches correlate with transcriptional down-regulation of GATA-2, an essential mast cell GATA factor, via switching of GATA-1 for GATA-2 at a key enhancer element upstream of the GATA-2 gene. These findings illustrate combinatorial control of cell fate identity by a transcription factor and its cofactor, and highlight the role of transcriptional networks in lineage determination. They also provide evidence for lineage instability during early stages of hematopoietic lineage commitment.

Friend of GATA-1-independent transcriptional repression: a novel mode of GATA-1 function

The GATA-1-interacting protein Friend Of GATA-1 (FOG-1) is essential for the proper transcriptional activation and repression of numerous GATA-1 target genes. Although FOG-1-independent activation by GATA-1 has been described, all known examples of GATA-1-mediated repression are FOG-1 dependent. In the GATA-1-null G1E cell line, estrogen receptor ligand binding domain (ER) chimeras of either wild-type GATA-1 or a FOG-1-binding defective mutant of GATA-1 repressed several genes similarly upon activation with beta-estradiol. Repression also occurred in a FOG-1-null cell line expressing ER-GATA-1 and during ex vivo erythropoiesis. At the Lyl1 and Rgs18 loci, we found highly restricted occupancy by GATA-1 and GATA-2, indicating that these genes are direct targets of GATA factor regulation. The identification of genes repressed by GATA-1 independent of FOG-1 defines a novel mode of GATA-1-mediated transcriptional regulation.

Burnout in Clinical Research Coordinators in the United States

PURPOSE/OBJECTIVES

To assess burnout among clinical research coordinators (CRCs) and to determine which personal and job-related factors are associated with burnout.

DESIGN

Random, stratified, cross-sectional mail survey.

SETTING

CRCs from membership lists of clinical research organizations.

SAMPLE

252 CRCs in the United States. To be included in the study, participants must have been in their current position longer than six months and involved in clinical trial coordination or data management. Of 2,770 records, 900 CRCs were mailed questionnaires; 35% (316) responded, and 252 of those were eligible for analysis. Eligible respondents were Caucasian (86%), female (94%), and employed full-time (92%) in an oncology setting (71%).

METHODS

Respondents completed mailed self-administered questionnaires measuring burnout, job satisfaction, personality characteristics, perceived work overload, and selected personal- and employment-related data. Data analyses included descriptive, univariate, and multivariate statistics.

MAIN RESEARCH VARIABLE

Burnout.

FINDINGS

About 70% of respondents were satisfied with their job, and 74% would still choose the clinical research profession. Approximately 44% reported high emotional exhaustion, a component of burnout. Factors independently associated with high emotional exhaustion burnout were low satisfaction with job (p 0.0001), high perceived daily workload (p 0.0001), and low endurance personality (p = 0.002).

CONCLUSIONS

Burnout is prevalent in CRCs. Job dissatisfaction, perceived daily work overload, low endurance, and nurturance personality traits were associated with high burnout.

IMPLICATIONS FOR NURSING

Nurses are involved significantly in clinical trial coordination. High burnout rates have potentially negative implications for data quality and productivity in clinical trial data management-important values for nursing and the clinical research profession.

Loss of nuclear p21(Cip1/WAF1) during neoplastic progression to metastasis in gamma-irradiated p21 hemizygous mice

p21(Cip1/WAF1) localizes to the nucleus in response to gamma-irradiation induced DNA damage and mediates a G(1) checkpoint arrest. Although gamma-irradiated p21(+/-) mice develop a broad spectrum of tumors, gamma-irradiated p21(-/-) mice develop significantly more metastatic cancers. To evaluate the expression of p21 in tissues prone or resistant to tumorigenesis as a function of gamma-irradiation, and to determine whether phenotypic loss of p21 heterozygosity occurs during tumor progression in p21(+/-) mice, tissues and tumors from gamma-irradiated mice were evaluated immunohistochemically. The percentage of tumors in p21(+/-) mice that were nuclear p21-positive declined with progression to metastasis (p<0.0001). Benign tumors were more often p21-positive and comprised of larger subsets of nuclear p21-positive cells than were malignant tumors of the same histopathological type, while metastatic cancers were nuclear p21-negative (p=0.0003). Even when a primary cancer was comprised of a subset of nuclear p21-positive cells, the metastatic foci of that same cancer were nuclear p21-negative. Mesenchymal tumors, though rare, were more likely metastatic than were epithelial tumors (p=0.0004), and these were invariably nuclear p21-negative. Prepubescent epithelial tissues from which most tumors later originated in mice with reduced p21 gene dosage (i.e., harderian gland, ovary, small intestine, and lung) were p21 expressive within 4 h of gamma-irradiation (p=0.0625), so that p21/Ki67 ratios increased post-gamma-irradiation (p=0.03). In contrast, p21 did not localize to nuclei of cortical thymocytes, a tissue where tumorigenesis was not augmented by reduced p21 gene dosage. Cellular subclones of malignant tumors, especially those of mesenchymal cell origin, which lack nuclear p21 may more readily acquire the genetic alterations of the metastatic phenotype.

Treatment of intermediate-risk prostate cancer with brachytherapy without supplemental pelvic radiotherapy: A review of the H. Lee Moffitt Cancer Center experience

PURPOSE

To determine the biochemical outcomes of patients with intermediate-risk prostate cancer treated at the H. Lee Moffitt Cancer Center with an I-125 permanent seed implant without supplemental pelvic radiotherapy.

METHODS AND MATERIALS

Under an institutional review board approved protocol, the charts of 88 patients with intermediate-risk prostate cancer and a minimum follow-up of 36 months treated with brachytherapy without supplemental pelvic radiotherapy were reviewed. Median follow-up for the whole cohort was 57 months (range 37-121). Biochemical failure was defined using the American Society for Therapeutic Radiology and Oncology definition.

RESULTS

The 5-year biochemical failure-free survival for the cohort was 83%. Patients with perineural invasion had a worse biochemical outcome, which was statistically significant (perineural invasion vs. no perineural invasion, 5-year biochemical failure-free survival 64% vs. 89%, P = 0.004). None of the following factors were found significant in this subset of patients: Gleason scores 6 versus 7, primary Gleason grades 3 versus 4, percentage of core positive <20% versus >20%, number of cores positive <2 versus 2 versus >2, hormonal therapy versus no hormonal therapy, T1 versus T2, prostate-specific antigen <10 versus >10, or > or =2 intermediate risk factors versus 1 intermediate risk factor.

CONCLUSIONS

Our data suggest that patients with intermediate-risk prostate cancer may be treated effectively with brachytherapy without supplemental pelvic radiotherapy. However, because of the limited nature of our study, we cannot exclude that patients with intermediate-risk prostate cancer may benefit from supplemental external beam radiotherapy.

Selective hepatic artery embolization for treatment of patients with metastatic carcinoid and pancreatic endocrine tumors

BACKGROUND

Prognosis in patients with carcinoid and pancreatic endocrine tumors with diffuse, unresectable liver metastases is poor. Palliation is often difficult despite the use of somatostatin analogs, interferon alpha, or systemic chemotherapy. Several reviews have suggested that hepatic artery embolization, with or without intraarterial chemotherapy, can be used for control of symptoms and for cytoreduction in patients with liver dominant metastases.

METHODS

Between 2000 and 2002, 161 embolizations using polyvinyl alcohol or microspheres were performed on 84 patients with carcinoid or pancreatic endocrine tumors metastatic to the liver. A retrospective review was performed to evaluate symptomatic response, biochemical response, adverse effects, and duration of survival. Baseline and follow-up computed tomography scans were also assessed to determine radiographic response rates. Further analysis of survival was performed to assess the possible impact of various postembolization therapies.

RESULTS

Eighty-four patients underwent bland hepatic artery embolizations during the study period. Among 55 symptomatic patients, 44 patients had fewer symptoms, and among 35 patients whose tumor markers were followed, 28 had a major biochemical response. Objective radiographic responses were observed in 11 of 23 patients. No deaths occurred during therapy, and major toxicities were rare. Median overall survival was 36 months from time of initial embolization.

CONCLUSIONS

Hepatic artery embolization frequently results in clinical and radiographic responses in patients with unresectable liver metastases from carcinoid or pancreatic endocrine tumors. Morbidity is low when appropriate supportive care is provided. Hepatic artery embolization often results in regressions in patients with unresectable liver metastases from carcinoid or pancreatic endocrine tumors.

A complication-free course ensures a survival advantage in patients after regional therapy for metastatic colorectal cancer

Hepatic artery infusional (HAI) chemotherapy has been shown to favorably impact outcome in patients with metastatic colorectal cancer, but complications often preclude complete treatment. The purpose of this study was to determine whether HAI complications impact survival in these patients. Patients undergoing HAI pump placement at our institution from September 2001 to July 2004 were separated into terciles based on the number of treatments completed: < or = 1 (none), 2 to 4 (partial), and > or = 5 (complete). Complications relating to pump placement or treatment were recorded for each and their impact on survival was determined. Kaplan-Meier survival in 15 patients receiving no treatment was significantly shorter than 7 patients completing therapy (P = 0.02). Thirty-three per cent of patients receiving no therapy were alive at 26 months, whereas 63 per cent of partially and 86 per cent of completely treated patients were alive at 32 and 30 months, respectively. Patients receiving no treatment had more overall complications (80%) and significantly (P < 0.05) more pump-related complications (60%) than those completing therapy (43% and 0%, respectively). Cox regression revealed a significant correlation to gender (hazard ratio, 3.9), tumor size (hazard ratio, 1.17), and carcinoembryonic antigen level (hazard ratio, 1.02) to survival. Patients receiving complete HAI treatment survive longer than those receiving no treatment. Potentially preventable pump-related complications not only impacted the patients' ability to continue therapy, but survival times as well.

A Complication-Free Course Ensures a Survival Advantage in Patients after Regional Therapy for Metastatic Colorectal Cancer

Hepatic artery infusional (HAI) chemotherapy has been shown to favorably impact outcome in patients with metastatic colorectal cancer, but complications often preclude complete treatment. The purpose of this study was to determine whether HAI complications impact survival in these patients. Patients undergoing HAI pump placement at our institution from September 2001 to July 2004 were separated into terciles based on the number of treatments completed: ≤1 (none), 2 to 4 (partial), and ≥5 (complete). Complications relating to pump placement or treatment were recorded for each and their impact on survival was determined. Kaplan-Meier survival in 15 patients receiving no treatment was significantly shorter than 7 patients completing therapy (P = 0.02). Thirty-three per cent of patients receiving no therapy were alive at 26 months, whereas 63 per cent of partially and 86 per cent of completely treated patients were alive at 32 and 30 months, respectively. Patients receiving no treatment had more overall complications (80%) and significantly (P < 0.05) more pump-related complications (60%) than those completing therapy (43% and 0%, respectively). Cox regression revealed a significant correlation to gender (hazard ratio, 3.9), tumor size (hazard ratio, 1.17), and carcinoembryonic antigen level (hazard ratio, 1.02) to survival. Patients receiving complete HAI treatment survive longer than those receiving no treatment. Potentially preventable pump-related complications not only impacted the patients’ ability to continue therapy, but survival times as well.

Pulmonary Embolism After Major Abdominal Surgery in Gynecologic Oncology

OBJECTIVE

To estimate the incidence and prognostic significance of postoperative pulmonary embolism after gynecologic oncology surgery.

METHODS

All patients who underwent gynecologic oncology surgery from June 2001 to June 2003 and received venous thromboembolism prophylaxis with only intermittent pneumatic compression and early ambulation were identified from our database. Patients were grouped by procedure (major/minor abdominal or nonabdominal surgery), diagnosis (malignant/nonmalignant), and cancer subtype. Groups were compared by chi2 analysis and logistic regression. Survival was studied with the Kaplan-Meier method and Mantel-Byar test.

RESULTS

A total of 1,373 surgical patients were identified over the 2-year period, including 839 major abdominal surgery cases and 534 minor abdominal surgery or nonabdominal surgery cases. Of the 839 patients, 507 had a diagnosis of cancer, and 332 were benign. The incidence of pulmonary embolism among cancer patients undergoing major abdominal surgery was 4.1% (21/507) compared with 0.3% (1/332) among patients undergoing major abdominal surgery with benign findings (P < .001, odds ratio [OR] 13.8, 95% confidence interval [CI] 1.9-102.1). The incidence of pulmonary embolism among patients undergoing minor/nonabdominal surgery was 0.4% (2/536). Cancer diagnosis and age more than 60 years were identified as risk factors for pulmonary embolism (P = .009, OR 0.31, 95% CI 0.13-0.74). One-year survival for patients with and those without pulmonary embolism were 48.0% +/- 12% and 77.0% +/- 2%, respectively.

CONCLUSION

Patients with cancer undergoing major abdominal surgery and using pneumatic compression for thromboembolic prophylaxis had a 14-fold greater odds of developing a pulmonary embolism compared with patients with benign disease. Randomized studies are needed to determine whether additional prophylactic measures may benefit this high-risk group of patients.

LEVEL OF EVIDENCE

II-3.

Prediction of radiation sensitivity using a gene expression classifier

The development of a successful radiation sensitivity predictive assay has been a major goal of radiation biology for several decades. We have developed a radiation classifier that predicts the inherent radiosensitivity of tumor cell lines as measured by survival fraction at 2 Gy (SF2), based on gene expression profiles obtained from the literature. Our classifier correctly predicts the SF2 value in 22 of 35 cell lines from the National Cancer Institute panel of 60, a result significantly different from chance (P = 0.0002). In our approach, we treat radiation sensitivity as a continuous variable, significance analysis of microarrays is used for gene selection, and a multivariate linear regression model is used for radiosensitivity prediction. The gene selection step identified three novel genes (RbAp48, RGS19, and R5PIA) of which expression values are correlated with radiation sensitivity. Gene expression was confirmed by quantitative real-time PCR. To biologically validate our classifier, we transfected RbAp48 into three cancer cell lines (HS-578T, MALME-3M, and MDA-MB-231). RbAp48 overexpression induced radiosensitization (1.5- to 2-fold) when compared with mock-transfected cell lines. Furthermore, we show that HS-578T-RbAp48 overexpressors have a higher proportion of cells in G2-M (27% versus 5%), the radiosensitive phase of the cell cycle. Finally, RbAp48 overexpression is correlated with dephosphorylation of Akt, suggesting that RbAp48 may be exerting its effect by antagonizing the Ras pathway. The implications of our findings are significant. We establish that radiation sensitivity can be predicted based on gene expression profiles and we introduce a genomic approach to the identification of novel molecular markers of radiation sensitivity.

Diagnosing pulmonary embolism: Experience with spiral CT pulmonary angiography in gynecologic oncology

OBJECTIVES

To review our experience with the diagnosis and prognosis of pulmonary embolism (PE) in gynecologic oncology patients.

METHODS

Spiral CT pulmonary angiography (CTPA) studies on gynecologic oncology patients were collected from our radiology database from 6/2001 to 6/2003. Patient charts were retrospectively reviewed. Data were abstracted relative to presenting symptoms, demographics and laboratory and diagnostic evaluations. Patient data were compared using chi-square contingency tables and logistic regression analysis. Survival was studied using the Kaplan-Meier method and the log rank test. The effect of PE on survival was adjusted using a proportional hazards regression model.

RESULTS

One-hundred and eleven CTPA studies were performed over 2 years and 25 patients were diagnosed with PE. Both PE (n = 25) and non-PE (n = 86) groups were similar for age, race, BMI and cancer diagnosis. Tachycardia (P = 0.02, OR = 3.03 [95% CI 1.16-7.94]) and leukocytosis (P = 0.04, OR = 2.93[95% CI 1.05-8.18]) were more frequent among PE patients and confirmed as independently prognostic of PE. All other clinical and laboratory findings were similar between patients with and without PE. Overall survival for patients with and without PE was 63% versus 94%, respectively, at 2 years (P = 0.02).

CONCLUSION

In a gynecologic oncology patient with high clinical suspicion for PE, our clinical pre-test probability was 23.0%. Two-year mortality rates were 6-fold higher for patients diagnosed with PE. The significant overlap in clinical presentations, multiple risk factors and higher mortality rates encourage the aggressive diagnosis and treatment of PE among this population. Further work is needed to reduce the incidence and mortality rate of PE.

The Efficacy and Safety of Pain Management Before and After Implementation of Hospital-Wide Pain Management Standards: Is Patient Safety Compromised by Treatment Based Solely on Numerical Pain Ratings?

Inadequate analgesia in hospitalized patients prompted the Joint Commission on Accreditation of Healthcare Organizations in 2001 to introduce standards that require pain assessment and treatment. In response, many institutions implemented treatment guided by patient reports of pain intensity indexed with a numerical scale. Patient safety associated with treatment of pain guided by a numerical pain treatment algorithm (NPTA) has not been examined. We reviewed patient satisfaction with pain control and opioid-related adverse drug reactions before and after implementation of our NPTA. Patient satisfaction with pain management, measured on a 1-5 scale, significantly improved from 4.13 to 4.38 (P < 0.001) after implementation of an NPTA. The incidence of opioid over sedation adverse drug reactions per 100,000 inpatient hospital days increased from 11.0 pre-NPTA to 24.5 post-NPTA (P < 0.001). Of these patients, 94% had a documented decrease in their level of consciousness preceding the event. Although there was an improvement in patient satisfaction, we experienced a more than two-fold increase in the incidence of opioid over sedation adverse drug reactions in our hospital after the implementation of NPTA. Most adverse drug reactions were preceded by a documented decrease in the patient's level of consciousness, which emphasizes the importance of clinical assessment in managing pain.

IMPLICATIONS

Although patient satisfaction with pain management has significantly improved since the adoption of pain management standards, adverse drug reactions have more than doubled. For the treatment of pain to be safe and effective, we must consider more than just a one-dimensional numerical assessment of pain.

GATA Transcription Factors in Hematologic Disease

GATA family transcription factors play essential roles in broad developmental settings. GATA-1, one of the hematopoietically expressed members, is required for normal erythroid and megakaryocytic differentiation. Over the past few years, mutations in the gene encoding GATA-1 have been linked to several human hematologic disorders, including X-linked dyserythropoietic anemia and thrombocytopenia, X-linked thrombocytopenia and beta-thalassemia, and Down syndrome acute megakaryoblastic leukemia. This review summarizes the role of GATA-1 during normal hematopoiesis and discusses how disease-associated mutations may affect its function.

Coregulation of GATA factors by the Friend of GATA (FOG) family of multitype zinc finger proteins

The Friend of GATA (FOG) family of proteins is an evolutionarily conserved class of large multitype zinc finger cofactors that bind to the amino zinc finger of GATA transcription factors and modulate their activity. Two FOG genes have been identified in mammals, both of which interact with each of the six known vertebrate GATA factors in vitro. Physical interaction between FOG and GATA proteins in vivo is essential for the development of a broad array of tissues, reflecting the overlapping expression patterns of these factors. In this review, we will discuss the identification and characterization of FOG proteins, their role in human disease, and recent studies that shed new light on their function and regulation.