Abstract 1821: MiR-9 is an oncogenic microRNA specifically overexpressed in MLL-rearrangement leukemia

Acute Leukemia is a heterogeneous disease derived from different hematopoietic cell lineages; acute leukemia both lymphoid and myeloid contains chromosomal including translocation of MLL (Mixed Lineage Leukemia), resulting in intermediate to poor survival. Aberrant expression of microRNAs (miRs) is an emerging hallmark of cancer biology; in particular, expression of microRNA-9 (miR-9) has been connected to several malignancies including breast, colon, prostate, lung, and ovarian cancers. However, miR-9 abnormalities have not been described in leukemia. We report that miR-9 is specifically overexpressed in MLL-rearranged acute myeloid leukemia (AML) relative to normal controls or other subtypes of AMLs. We showed that MLL fusion proteins directly regulate miR-9 expression by binding to its promoter region. Forced expression of miR-9 alone does not transform normal hematopoietic progenitor cells but in the presence of MLL-AF9, one of the most frequent MLL-rearranged fusion gene resulting from t(9;11), results in a significant enhance of the colony forming/replating capacity of normal hematopoietic progenitor cells. The use of a competitor inhibitor (miR-9 sponge) resulted in a significant reduction of colony formation and an increase in differentiated hematopoietic cells, indicating miR-9 is required for MLL-AF9 colony-forming growth and maintenance of the immature cell population. Through further functional analysis we found that miR-9 is required for MLL-AF9-mediated cell transformation in vitro. Using mouse bone marrow transplant assays we discovered that forced expression of miR-9 could significantly accelerate leukemogenesis mediated by MLL-AF9. The addition of miR-9 to MLL-AF9 also resulted in an increase in immature hematopoietic progenitor cells indicating more potent long-term leukemia potential in vivo. To identify miR-9 targets we analyzed our in-house and publically available gene expression data from the Gene Expression Omnibus (GEO) at the National Center for Biotechnology Information (NCB I) in Acute Leukemia patients containing MLL-rearrangements. We determined that MLL-leukemias contained a unique deregulated gene signature. As microRNAs most commonly inhibit target genes through binding of the 3’ untranslated region (UTR) we identified genes that were significantly inhibited in MLL-leukemias and were predicted targets of miR-9. From the several genes we identified we selected six genes (based on best inverse correlation to miR-9 expression) to validate as targets of miR-9 in MLL-rearranged leukemias. We validated these genes as miR-9 targets and continue to investigate their contribution to MLL-rearranged leukemias. As these genes are potentially involved in several biological processes we believe that miR-9 in the presence of MLL fusions is an important contributor to leukemogenesis and could be a potential target for future antimir therapy.

Citation Format: Colles Price, Ping Chen, Zejuan Li, Yuanyuan Li, Anissa Wiley, Donglin Cao, Chunjiang He, Rejani Kunjamma, Hao Huang, Xi Jiang, Stephen Arnovitz, Mary Beth Neilly, Janet Rowley, Jianjun Chen. MiR-9 is an oncogenic microRNA specifically overexpressed in MLL-rearrangement leukemia. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1821. doi:10.1158/1538-7445.AM2013-1821

Blockade of miR-150 maturation by MLL-fusion/MYC/LIN-28 is required for MLL-associated leukemia

Expression of microRNAs (miRNAs) is under stringent regulation at both transcriptional and posttranscriptional levels. Disturbance at either level could cause dysregulation of miRNAs. Here, we show that MLL fusion proteins negatively regulate production of miR-150, an miRNA widely repressed in acute leukemia, by blocking miR-150 precursors from being processed to mature miRNAs through MYC/LIN28 functional axis. Forced expression of miR-150 dramatically inhibited leukemic cell growth and delayed MLL-fusion-mediated leukemogenesis, likely through targeting FLT3 and MYB and thereby interfering with the HOXA9/MEIS1/FLT3/MYB signaling network, which in turn caused downregulation of MYC/LIN28. Collectively, we revealed a MLL-fusion/MYC/LIN28⊣miR-150⊣FLT3/MYB/HOXA9/MEIS1 signaling circuit underlying the pathogenesis of leukemia, where miR-150 functions as a pivotal gatekeeper and its repression is required for leukemogenesis.

Abstract 2309: Down-regulation of miR-181b contributes to the poor prognosis of adverse cytogenetically abnormal acute myeloid leukemia by targeting PBX3

Altered expression of microRNAs (miRNAs, a class of small regulatory RNAs) is associated with various types of cancers, including acute myeloid leukemia (AML). In our previous bead-based miRNA expression profiling assay, we observed that miR-181a, b, c, and d were all expressed at a higher level in the favorable prognosis subtypes of cytogenetically abnormal AML (CA-AML) carrying t(8;21), inv(16), or t(15;17) than in an intermediate- to poor-risk subtype of CA-AML harboring MLL rearrangements. Indeed, we found that increased expression of miR-181a or miR-181b was significantly (P<0.05) associated with longer OS in univariable testing, whereas only that of miR-181b remained significant (P<0.05) upon multivariable testing, after adjusting for other clinical, cytogenetic, and molecular variables. Through correlating expression of miR-181b with those of miR-181 putative target genes in 35 CA-AML patient samples, we identified 159 genes that exhibited a significantly inverse (P<0.05; Pearson Correlation) correlation of expression with miR-181b. PBX3 has the most significant inverse correlation with the expression of miR-181b, so we chose PBX3 as an important candidate target of miR-181 for further studies. We conducted luciferase reporter and mutagenesis assays and showed that PBX3 is a direct target of miR-181a/b. We also showed that forced expression of miR-181a/b significantly down-regulated endogenous expression of PBX3 in MLL-rearranged leukemic cells at both the RNA and protein levels. Ectopic expression of miR-181b significantly (P<.05) promoted apoptosis and decreased viability of MONOMAC-6/t(9;11), THP-1/t(9;11), and KOCL-48/t(4;11), and delayed leukemogenesis in MLL-fusion-mediated mouse leukemia model; such effects could be reversed by forced expression of PBX3 coding region. Our data suggest that the silencing of miR-181b and thereby the activation of the target genes, such as PBX3, likely contributes to the poor prognosis of adverse CA-AML patients. Thus, restoring expression of miR-181b and/or targeting the PBX3 pathways in poor prognosis AML patients may provide new strategies to improve outcome substantially.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2309. doi:1538-7445.AM2012-2309

Long-term glycaemic outcome of structured nurse-led diabetes care in rural Africa

BACKGROUND

Diabetes care delivery in rural Africa is difficult. Problems include lack of dedicated personnel, monitoring systems, laboratory support and drugs. Few structured intervention projects have been undertaken, none with long-term follow-up.

AIM

To determine the long-term (4 years) glycaemic outcome of a structured nurse-led intervention programme for type 2 diabetic patients in rural Africa.

DESIGN

Single-centre, observational cohort study.

METHODS

The programme was delivered in the scattered primary health clinics of Hlabisa District, in northern Kwazulu Natal, South Africa. Monthly diabetic clinics were held at which empowerment-based education was delivered and regularly reinforced. Oral hypoglycaemic agents (OHAs) were titrated according to a previously validated clinical algorithm. Outcome was measured by glycated haemoglobin (HbA(1)c), as well as body mass index (BMI). Data were collected at baseline, and then 6, 18, 24 and 48 month's post-intervention.

RESULTS

Eighty patients had data available at all time collection points. They were of mean ± SD, age 56 ± 11 years, 70% were female, BMI 31.5 ± 7.2 kg/m(2) and HbA(1)c 10.8 ± 4.2%. HbA(1)c fell significantly to 8.1 ± 2.2% at 6 months and 7.5 ± 2.0% at 18 months. By 24 months, it had risen (8.4 ± 2.3%), and at 4 years post-intervention it was 9.7 ± 4.0% (still significantly lower than baseline, P = 0.015). BMI rose significantly at 6 and 18 months, but by 48 months was not significantly different from baseline.

CONCLUSION

We conclude that the intervention led to marked HbA(1)c improvements up to 18 months follow-up, but thereafter there was 'glycaemic slippage'. This may be not only due to educational 'wear-off', noted in other education-intervention programmes, but also to the expected glycaemic deterioration with time known to occur in type 2 diabetes. Nevertheless, 4-year HbA(1)c levels were still significantly lower than at baseline. The programme was also well received by staff and patients, and we believe is an appropriate and effective diabetes intervention system in rural Africa.

Simple repair of a giant inguinoscrotal hernia

We present a case of a giant inguinoscrotal hernia that extended almost to the patient's knees. Operative repair was through a standard transverse inguinal incision. No debulking or abdominal enlargement procedure had to be performed. The repair was done with a tension-free, onlay, prosthetic mesh repair.

Media coverage and public reaction to a celebrity cancer diagnosis

BACKGROUND

Celebrity diagnoses can have important effects on public behaviour. UK television celebrity Jade Goody died from cervical cancer in 2009. We investigated the impact of her illness on media coverage of cervical cancer prevention, health information seeking behaviour and cervical screening coverage.

METHODS

National UK newspaper articles containing the words 'Jade Goody' and 'cancer' were examined for public health messages. Google Insights for Search was used to quantify Internet searches as a measure of public health information seeking. Cervical screening coverage data were examined for temporal associations with this story.

RESULTS

Of 1203 articles, 116 (9.6%) included a clear public health message. The majority highlighted screening (8.2%). Fewer articles provided advice about vaccination (3.0%), number of sexual partners (1.4%), smoking (0.6%) and condom use (0.4%). Key events were associated with increased Internet searches for 'cervical cancer' and 'smear test', although only weakly with searches for 'HPV'. Cervical screening coverage increased during this period.

CONCLUSION

Increased public interest in disease prevention can follow a celebrity diagnosis. Although media coverage sometimes included public health information, articles typically focused on secondary instead of primary prevention. There is further potential to maximize the public health benefit of future celebrity diagnoses.

Genetic variation in the structural pattern of osteoclast activity during post-natal growth of mouse femora

While the spatial activity of osteoblasts has been associated with modeling of bones during development, few studies have examined if variation in the spatial activity of osteoclasts also contributes to the morphogenesis of skeletal tissues. We examined this question by histomorphometric analysis and reconstructing the three-dimensional spatial distribution of osteoclasts in the femora of three inbred strains of male mice (A/J, C57BL/6J [B6], and C3H/HeJ [C3H]) that have differing skeletal, structural, and material properties. Our data show that total osteoclast surface area and osteoclast numbers are related to the overall bone density, but not related to the development of bone diameter or overall cortical area. The analysis of the spatial distribution of the osteoclasts showed that the asymmetrical mid-diaphyseal distribution of osteoclasts in A/J and B6 compared to the more uniform distribution of these cells around the circumference in the C3H mice was consistent with the more ellipsoid shape of A/J and B6 femora compared to the more circular mid-diaphyseal shape of the femora in the C3H mice. The statistically 2- to 3-fold fewer cells on the periosteal surface in the C3H compared to either the B6 or A/J mice is also consistent with the greater cortical thickness that is seen for the C3H mice compared to either B6 or A/J strains. In vitro studies of osteoclastogenesis and the expression of numerous phenotypic properties of osteoclasts prepared from the three strains of mice showed that A/J and B6 mice developed statistically greater numbers of tartrate resistant acid phosphatase (TRAP) positive cells and expressed statistically higher levels of multiple mRNAs that are unique to differentiated osteoclasts than those isolated from the C3H strain. In summary, the 3D reconstructions and histomorphometric analysis suggest that genetic differences lead to spatial variation in the distribution of osteoclasts. These variations in spatial distribution of osteoclasts in turn contribute in part to the development of the structural variations of the femora that are seen in the three strains of mice. In vitro studies suggest that intrinsic genetic variation in osteoclastogenesis and their phenotypic expression may contribute to the differences in their functional activities that give rise to the unique spatial distributions of these cells in bones.

Influences on self-evaluation during a clinical skills programme for nurses

Education has moved from teacher to student-centred practices. Increasing emphasis is placed on 'life-long' learning in the context of a rapidly changing knowledge base. Self-evaluation is seen as one strategy to facilitate student-centred continuous professional development. The literature, however, suggests that learners' ability to self-assess is mixed, and little is known regarding how students perform self-assessment. This study focussed on senior nurses undertaking a scenario-based clinical skills course. Learners were asked to self-evaluate several times during the course. This research explored the influences on using the self-evaluation exercise. The study drew upon grounded theory methodology and was influenced by constructionist and postmodernist theories. Three methods of data collection were used: semi-structured interviews, observation of supervision sessions and recording of the numerical self-evaluation ratings. Multiple interviews with students (n = 14) and the educational supervisor (n = 1) were conducted. Thematic analysis and data collection were conducted iteratively. The study found that feeling confident and stating that confidence were not necessarily the same. Feeling confident was complex, influenced by changing perceptions of clinical skills and credibility. Changing frames of reference were used to judge feelings of confidence. Stating confidence appeared to be socially negotiated, influenced by social acceptability considerations such as modesty and the need to show progress over time. The discourses of empowerment and surveillance were influential and self-evaluation is discussed using Foucault's theory of governmentality, illustrating how learners can be both empowered and controlled through self-evaluation. Further consideration of the socially constructed nature of self-evaluations would benefit both educational practice and future research.

The displaced equine soft palate as a source of abnormal respiratory noise during expiration

REASONS FOR PERFORMING STUDY

To develop the technique of respiratory sound analysis for the diagnosis of dorsal displacement of the equine soft palate.

OBJECTIVES

To show that 1) the displaced soft palate can spontaneously vibrate in the presence of expiratory airflow; 2) the observed frequency of vibration can be detected in respiratory sound recordings; and 3) the frequency of vibrations measured in cadaveric specimens are similar to those obtained from audio spectra in exercising horses with DDSP.

METHODS

Palatal movements and respiratory sounds were recorded from artificially ventilated cadaveric heads. The fundamental mode of palate vibrations calculated from high-speed videoendoscopic recordings was compared with frequencies detected in the audio spectra and with data collected from exercising horses with DDSP.

RESULTS

Palate vibrations occurred when air was blown through the trachea. The fundamental mode of vibrations was present in the audio spectra and was not significantly different from those recorded in vivo.

CONCLUSIONS

Vibrations of the soft palate are the probable source of expiratory sounds recorded in horses with DDSP.

POTENTIAL RELEVANCE

This study strengthens the case for the application of respiratory sound analysis in the diagnosis of DDSP in exercising horses.