C-reactive protein-based tuberculosis triage testing: a multi-country diagnostic accuracy study.

Rationale: C-reactive protein (CRP)-based tuberculosis (TB) screening is recommended for people with HIV (PWH). However, its performance among people without HIV and in diverse settings is unknown. Objectives: In a multi-country study, we aimed to determine whether CRP meets the minimum accuracy targets (sensitivity ≥90%, specificity ≥70%) for an effective TB triage test. Methods/Measurements: Consecutive outpatient adults with cough ≥2 weeks from five TB endemic countries in Africa and Asia had baseline blood collected for point-of-care CRP testing and HIV and diabetes screening. Sputum samples were collected for Xpert MTB/RIF Ultra (Xpert) testing and culture. CRP sensitivity and specificity (5 mg/L cut-point) was determined in reference to sputum test results and compared by country, sex, and HIV and diabetes status. Variables affecting CRP performance were identified using a multivariate receiver operating characteristic (ROC) regression model. Results: Among 2904 participants, of whom 613 (21%) had microbiologically-confirmed TB, CRP sensitivity was 84% (95% CI: 81-87%) and specificity was 61% (95% CI: 59-63%). CRP accuracy varied geographically, with higher sensitivity in African countries (≥91%) than Asian countries (64-82%). Sensitivity was higher among men than women (87% vs. 79%, difference +8%, 95% CI: 1-15%) and specificity was higher among people without HIV than PWH (64% vs. 45%, difference +19%, 95% CI: 13-25%). ROC regression identified country and measures of TB disease severity as predictors of CRP performance. Conclusions: Overall, CRP did not achieve the minimum accuracy targets and its performance varied by setting and in some sub-groups, likely reflecting population differences in mycobacterial load.

Impact of post-COVID-19 lung damage on pulmonary function, exercise tolerance and quality of life in Indian subjects.

After recovery from COVID-19, there is data to suggest potential long-term pulmonary sequelae and associated impairment of functional capacity. This cross-sectional study was designed to assess the impact on respiratory function in a cohort of Indian subjects. Subjects who had recovered from COVID-19 were recruited. Clinical symptoms, pulmonary function test results, 6-minute walk test (6MWT) results, St George's Respiratory questionnaire (SGRQ) and chest radiographs were obtained. Information on the COVID-19 illness during hospitalization, baseline laboratory biomarkers and the disease severity categories as outlined by WHO (asymptomatic, mild, moderate, severe and critical), were retrieved from the hospital records. The 'COVID pneumonia'(WHO category moderate, severe & critical) group was compared with the 'Mild COVID' (WHO category mild) group and likewise, the WHO category moderate and the WHO category severe/critical groups were compared. In 207 subjects, whose mean age was 48.7 years were assessed after an average of 63 days from onset of symptom, 35% had TLC< 80% (restrictive defect), 8.3% had FEV1/FVC<70% (obstructive defect) and 44.4% had diminished DLCO<80% (diffusing capacity). The 'COVID-19 pneumonia' group when compared to the 'mild COVID-19' group, had lower FVC% (77.85 VS 88.18; P = 0.001), TLC% (79.48 VS 87.91; P = 0.0002), DLCO% (75.30 VS 89.20; P<0.0001) and DLCO/VA% (105.6 VS 111.8; P = 0.032), decreased minimum oxygen saturation (94.89 VS 97.73; P<0.0001) and more subjects had a drop in saturation of ≥ 4% (21.69% VS 4.84%; P = 0.001) during the 6MWT, and a greater mean total SGRQ score (29.2 VS 11.0; P<0.0001). To our knowledge, this is the first such report on Indian subjects. We have shown that post-COVID-19 lung damage leads to significant impairment of lung function, quality of life and effort tolerance.

Tuberculin test using Indian indigenous purified-protein derivative (PPD) shows only moderate agreement with international standard PPD.

Background: In India, the prevalence of Latent TB infection (LTBI) is estimated to be around 40%. Various formulations of PPD(Purified protein derivative) are available, for diagnosis of LTBI, which may give variable responses. The commercially available PPD in India is by Arkray Healthcare (TST-Arkray). It is unclear if this product may have a similar sensitivity compared to other internationally accepted tuberculins (TST-Tubersol). Objectives: To assess the performance of the two TSTs compared to Quantiferon-Gold Plus (QFT-Plus). Methodology: A blood sample was collected for the QFT-Plus test. Both the TSTs were placed in the right and the left volar aspect of the forearms and 48 hrs later, the subjects came back to the study site for reading. Results: Among the 512 participants who were recruited, 326 subjects were healthcare professionals and 186 subjects were household contacts of patients with tuberculosis. They were tested with both TST-Tubersol and TST-Arkray, 139(27 %) participants tested positive for TST-Tubersol (≥10 mm), whereas 203 participants (40.1 %)tested positive for TST-Arkray. There was moderate agreement between the two tests with k = 0.58. Also, there was only poor agreement between both the TSTs with QFT Plus(kappa = 0.19 for Tubersol and 0.17 for Arkray). With QFT-Plus as gold standard, the sensitivity, specificity, PPV and NPV of TST-Tubersol, ast an induration cut-off of 10 mm was 46.8 %,76.3 %,31.8 % and 85.8 %. respectively and TST- Arkray; 60.6 %, 64 %, 28.5 % and 87.2 % respectively. Conclusion: The Indian TST (Arkray Diagnostics) has shown moderate agreement with the internationally accepted Tubersol. Additionally, there was poor agreement between the TSTs and QFT plus test.

Rural South Indian spirometry values show wide variation compared to existing prediction equations.

Background and Objective: India, a highly heterogeneous country, has no common reference standards for predicting spirometry values, with very few recent studies from south India. This study aimed to create reference equations for rural south Indian adults, based on a population-based survey in Vellore, south India and compare it with other equations from India. Methods: The data from 583 non-smoking, asymptomatic participants (30 years and older) from a spirometry-based survey for airflow obstruction (rural Vellore, 2018), were used to develop equations for FEV1, FEV1/FVC, and FVC. The dataset was divided for development (70%) and validation (30%), by gender. Differences between observed and predicted values were assessed using the new equations and comparisons made with other equations from India. Results: Predictions with Vellore rural equations were closest to the previous south Indian equations from urban Bangalore. However, the Bangalore equations led to overestimation of FVC values in males, and of both FEV1 and FVC values in females. Using the rural Vellore equations also led to a higher percent of males being classified as having airflow obstruction, compared to the Bangalore equations which underestimated airflow obstruction in this rural population. Comparison with previously derived Indian equations from other parts of the country showed pronounced variations. Conclusions: Our study reiterates the need for representative rural and urban studies of adults from various parts of India, to obtain region specific reference equations, given the wide variations in spirometry values in "normal" individuals, due to social heterogeneities of the Indian population and resulting complexities in defining normal.

Pharmacokinetics of rifampicin, isoniazid & pyrazinamide during daily & intermittent dosing: A preliminary study.

Background & objectives: The National Tuberculosis (TB) Control Programme has transitioned from thrice-weekly to daily drug treatment regimens in India. This preliminary study was conceived to compare the pharmacokinetics of rifampicin (RMP), isoniazid (INH) and pyrazinamide (PZA) in TB patients being treated with daily and thrice weekly anti-TB treatment (ATT). Methods: This prospective observational study was undertaken in 49 newly diagnosed adult TB patients receiving either daily ATT (n=22) or thrice-weekly ATT (n=27). Plasma RMP, INH and PZA were estimated by high-performance liquid chromatography. Results: The peak concentration (Cmax) of RMP was significantly higher (RMP: 8.5 µg/ml vs. 5.5 µg/ml; P=0.003) and Cmax of INH was significantly lower (INH: 4.8 µg/ml vs. 10.9 µg/ml; P<0.001) in case of daily dosing compared to thrice-weekly ATT. Cmax of drugs and doses was significantly correlated. A higher proportion of patients had subtherapeutic RMP Cmax (8.0 µg/ml) during thrice-weekly compared to daily ATT (78% vs. 36%; P=0.004). Multiple linear regression analysis showed that Cmax of RMP was significantly influenced by the dosing rhythm, pulmonary TB and Cmax of INH and PZA by the mg/kg doses. Interpretation & conclusions: RMP concentrations were higher and INH concentrations were lower during daily ATT, suggesting that INH doses may need to be increased in case of a daily regimen. Larger studies are, however, required using higher INH doses when monitoring for adverse drug reactions and treatment outcomes.

Random embedded calibrated statistical blind steganalysis using cross validated support vector machine and support vector machine with particle swarm optimization.

The evolvement in digital media and information technology over the past decades have purveyed the internet to be an effectual medium for the exchange of data and communication. With the advent of technology, the data has become susceptible to mismanagement and exploitation. This led to the emergence of Internet Security frameworks like Information hiding and detection. Examples of domains of Information hiding and detection are Steganography and steganalysis respectively. This work focus on addressing possible security breaches using Internet security framework like Information hiding and techniques to identify the presence of a breach. The work involves the use of Blind steganalysis technique with the concept of Machine Learning incorporated into it. The work is done using the Joint Photographic Expert Group (JPEG) format because of its wide use for transmission over the Internet. Stego (embedded) images are created for evaluation by randomly embedding a text message into the image. The concept of calibration is used to retrieve an estimate of the cover (clean) image for analysis. The embedding is done with four different steganographic schemes in both spatial and transform domain namely LSB Matching and LSB Replacement, Pixel Value Differencing and F5. After the embedding of data with random percentages, the first order, the second order, the extended Discrete Cosine Transform (DCT) and Markov features are extracted for steganalysis.The above features are a combination of interblock and intra block dependencies. They had been considered in this paper to eliminate the drawback of each one of them, if considered separately. Dimensionality reduction is applied to the features using Principal Component Analysis (PCA). Block based technique had been used in the images for better accuracy of results. The technique of machine learning is added by using classifiers to differentiate the stego image from a cover image. A comparative study had been during with the classifier names Support Vector Machine and its evolutionary counterpart using Particle Swarm Optimization. The idea of cross validation had also been used in this work for better accuracy of results. Further parameters used in the process are the four different types of sampling namely linear, shuffled, stratified and automatic and the six different kernels used in classification specifically dot, multi-quadratic, epanechnikov, radial and ANOVA to identify what combination would yield a better result.

Prevalence of Airflow Obstruction as Measured by Spirometry, in Rural Southern Indian Adults.

Rural population-based estimates of airflow obstruction based on spirometry are unavailable from southern India. This study assessed the prevalence of spirometry-defined airflow obstruction in Vellore, Tamil Nadu.A cross sectional survey was done in nine villages, among adults aged ≥30 years, where previous cardiovascular surveys had been conducted (1994, 2011). Population proportional to size sampling was used to select 20 clusters, with sampling from all streets proportional to the number of households. One person randomly selected per household was interviewed for symptoms and risk factors. A respiratory therapist performed pre and post bronchodilator spirometry on all, following American Thoracic Society criteria. Airflow obstruction was defined as pre-bronchodilator Forced Expiratory Volume 1 s/Forced Vital Capacity (FEV1/FVC) < Lower Limit of Normal (LLN, derived from local prediction equations) and compared to other criteria.Of 1015 participants, 787 completed technically acceptable spirometry. The prevalence of airflow obstruction was 9.0% (95% CI: 5.8%-9.6%, 71). Fixed obstruction (post bronchodilator FEV1/FVC < LLN) was 4.6% (95% CI: 3.1%-6.1%, 36), and 4.1% (95% CI: 2.7%-5.5%, 32) using post bronchodilator FEV1/FVC < 70%. The GOLD criteria missed 56% (40) of those with airflow obstruction, of which 87.5% were females. Although 63.4% with airflow obstruction had moderate to severe disease, 82.2% were not on treatment and only 48.9% reported symptoms in the previous year.This study estimates prevalence of airflow obstruction based on spirometry in rural southern India. Despite significant impairment on spirometry, majority were undiagnosed, and half did not report symptoms.

Low Potency of Indian Dust Mite Allergen Skin Prick Test Extracts Compared to FDA-Approved Extracts: A Double-Blinded Randomized Control Trial.

BACKGROUND: Skin prick testing is the most important diagnostic tool to detect immunoglobulin E-mediated allergic diseases. With increase in the number of allergy tests performed in India, it is imperative to know the potency of indigenous extracts in comparison with U.S. Food and Drug Administration (USFDA)-approved extracts. METHODS: A randomized comparison trial of Indian manufactured and USFDA-approved extracts of Dermatophagoides pteronyssinus (DP) and Dermatophagoides farinae (DF) was done at Christian Medical College & Hospital, Vellore, India from April 2014 to June 2015, to compare the skin test reactivity of indigenous allergen extracts of dust mites against validated allergen. Study enrollment included 197 patients with allergic disorders that showed sensitivity to dust mite during routine allergy skin testing. Study participants were tested with varying dilutions of DP and DF indigenous extracts along with USFDA-approved allergens in a blinded fashion. Results were recorded, and statistical significance was calculated using the Friedman rank sum test. RESULTS: Using the Friedman rank sum test with a Tukey adjustment for multiple comparisons, we found that the extracts in each dilution were significantly different (P < .0001). The full strength indigenous extracts, B-DF (DF allergen standard extract from Bioproducts and Diagnostics, India) and C-DF (DF allergen extract from Creative Diagnostics, India) extracts, had mean wheal sizes of 7.69 (standard deviation [SD] 9.91) and 31.01(SD 51.04), respectively. The full strength S-DF (DF allergen extract from Jubilant Hollister Stier, Spokane, WA, USA) had a mean wheal size of 109.97 (SD 162.73), which was significantly higher (P < .0001) than both the indigenous extracts. For each of the dilutions, the S-DF mean wheal size was significantly greater than that of the corresponding B-DF and C-DF wheal sizes. The full strength indigenous C-DP (DP allergen extract from Creative Diagnostics, India) had mean wheal size of 39.37 (SD 51.74). The full strength standard S-DP (DP allergen extract from Jubilant Hollister Stier, Spokane, WA, USA) extract had a mean wheal size of 167.66 (SD 270.80), which was significantly higher (P < .0001) than the indigenous C-DP extract. Similar differences were seen across all dilutions. CONCLUSION: The indigenous extracts have significantly lower potency compared to USFDA-approved extracts; hence, there is an urgent need for policy makers to institute stringent criteria for standardization of antigens in India.

Safety of the two-step tuberculin skin test in Indian health care workers.

BACKGROUND: Health care workers (HCW) in low and middle income countries are at high risk of nosocomial tuberculosis infection. Periodic screening of health workers for both TB disease and infection can play a critical role in TB infection control. Occupational health programs that implement serial tuberculin skin testing (TST) are advised to use a two-step baseline TST. This helps to ensure that boosting of waned immune response is not mistaken as new TB infection (i.e. conversion). However, there are no data on safety of the two-step TST in the Indian context where HCWs are repeatedly exposed. MATERIALS AND METHODS: Nursing students were recruited from 2007 to 2009 at the Christian Medical College and Hospital, Vellore, India. Consenting nursing students were screened with a baseline two-step TST at the time of recruitment. From 2007 to 2008 adverse events were recorded when reported during the TST reading (Cohort A). Nurses recruited in the final study year (2009) answered an investigator administered questionnaire assessing all likely side-effects Cohort B). This information was extracted from the case report forms and analysed. RESULTS: Between 2007 and 09, 800 trainees consented to participate in the annual TB screening study and 779 did not have a past history of TB or recall a positive TST and were selected to administer TST. Of these, 755 returned for reading the result and had complete data and were included for the final analysis - 623 subjects in (cohort A) and 132 in (cohort B). These were included for the final analysis. In cohort A only 1.3% reported adverse events. In cohort B, as per the investigator administered questionnaire; 25% reported minor side effects. Itching and local pain were the most common side effects encountered. There were no major adverse events reported. In particular, the adverse events were similar in the second step of the test and not more severe. CONCLUSION: Screening of HCWs with two-step TST for LTBI is simple and safe, and hence suitable for wide scale implementation in high-burden settings such as India.

Challenges in the development of an immunochromatographic interferon-gamma test for diagnosis of pleural tuberculosis.

Existing diagnostic tests for pleural tuberculosis (TB) have inadequate accuracy and/or turnaround time. Interferon-gamma (IFNg) has been identified in many studies as a biomarker for pleural TB. Our objective was to develop a lateral flow, immunochromatographic test (ICT) based on this biomarker and to evaluate the test in a clinical cohort. Because IFNg is commonly present in non-TB pleural effusions in low amounts, a diagnostic IFNg-threshold was first defined with an enzyme-linked immunosorbent assay (ELISA) for IFNg in samples from 38 patients with a confirmed clinical diagnosis (cut-off of 300 pg/ml; 94% sensitivity and 93% specificity). The ICT was then designed; however, its achievable limit of detection (5000 pg/ml) was over 10-fold higher than that of the ELISA. After several iterations in development, the prototype ICT assay for IFNg had a sensitivity of 69% (95% confidence interval (CI): 50-83) and a specificity of 94% (95% CI: 81-99%) compared to ELISA on frozen samples. Evaluation of the prototype in a prospective clinical cohort (72 patients) on fresh pleural fluid samples, in comparison to a composite reference standard (including histopathological and microbiologic test results), showed that the prototype had 65% sensitivity (95% CI: 44-83) and 89% specificity (95% CI: 74-97). Discordant results were observed in 15% of samples if testing was repeated after one freezing and thawing step. Inter-rater variability was limited (3%; 1 out of 32). In conclusion, despite an iterative development and optimization process, the performance of the IFNg ICT remained lower than what could be expected from the published literature on IFNg as a biomarker in pleural fluid. Further improvements in the limit of detection of an ICT for IFNg, and possibly combination of IFNg with other biomarkers such as adenosine deaminase, are necessary for such a test to be of value in the evaluation of pleural tuberculosis.

CREB is a critical regulator of normal hematopoiesis and leukemogenesis.

The cAMP-responsive element binding protein (CREB) is a 43-kDa nuclear transcription factor that regulates cell growth, memory, and glucose homeostasis. We showed previously that CREB is amplified in myeloid leukemia blasts and expressed at higher levels in leukemia stem cells from patients with myeloid leukemia. CREB transgenic mice develop myeloproliferative disease after 1 year, but not leukemia, suggesting that CREB contributes to but is not sufficient for leukemogenesis. Here, we show that CREB is most highly expressed in lineage negative hematopoietic stem cells (HSCs). To understand the role of CREB in hematopoietic progenitors and leukemia cells, we examined the effects of RNA interference (RNAi) to knock down CREB expression in vitro and in vivo. Transduction of primary HSCs or myeloid leukemia cells with lentiviral CREB shRNAs resulted in decreased proliferation of stem cells, cell- cycle abnormalities, and inhibition of CREB transcription. Mice that received transplants of bone marrow transduced with CREB shRNA had decreased committed progenitors compared with control mice. Mice injected with Ba/F3 cells expressing either Bcr-Abl wild-type or T315I mutation with CREB shRNA had delayed leukemic infiltration by bioluminescence imaging and prolonged median survival. Our results suggest that CREB is critical for normal myelopoiesis and leukemia cell proliferation.

A highly conserved regulatory element controls hematopoietic expression of GATA-2 in zebrafish.

BACKGROUND: GATA-2 is a transcription factor required for hematopoietic stem cell survival as well as for neuronal development in vertebrates. It has been shown that specific expression of GATA-2 in blood progenitor cells requires distal cis-acting regulatory elements. Identification and characterization of these elements should help elucidating transcription regulatory mechanisms of GATA-2 expression in hematopoietic lineage. RESULTS: By pair-wise alignments of the zebrafish genomic sequences flanking GATA-2 to orthologous regions of fugu, mouse, rat and human genomes, we identified three highly conserved non-coding sequences in the genomic region flanking GATA-2, two upstream of GATA-2 and another downstream. Using both transposon and bacterial artificial chromosome mediated germline transgenic zebrafish analyses, one of the sequences was established as necessary and sufficient to direct hematopoietic GFP expression in a manner that recapitulates that of GATA-2. In addition, we demonstrated that this element has enhancer activity in mammalian myeloid leukemia cell lines, thus validating its functional conservation among vertebrate species. Further analysis of potential transcription factor binding sites suggested that integrity of the putative HOXA3 and LMO2 sites is required for regulating GATA-2/GFP hematopoietic expression. CONCLUSION: Regulation of GATA-2 expression in hematopoietic cells is likely conserved among vertebrate animals. The integrated approach described here, drawing on embryological, transgenesis and computational methods, should be generally applicable to analyze tissue-specific gene regulation involving distal DNA cis-acting elements.

Potential role of CREB as a prognostic marker in acute myeloid leukemia.

The cAMP response element binding protein (CREB) is a leucine zipper transcription factor that regulates genes responsible for cell proliferation, differentiation and survival. CREB is overexpressed in the bone marrow from most patients with acute leukemia. Overexpression of CREB occurs both at the protein and at the transcript levels and is associated with gene amplification in leukemic blast cells. Higher levels of CREB correlate with a less favorable prognosis in a small cohort of adult patients with acute myeloid leukemia. In one study, patients whose bone marrow over-expresses CREB had an increased risk of relapse and decreased event-free survival. Mice that overexpress CREB in myeloid cells develop a myeloproliferative/myelodysplastic syndrome. These findings suggest that CREB plays an important role in the pathogenesis of acute leukemia and is a potential biomarker of disease.

ABT-869, a multitargeted receptor tyrosine kinase inhibitor: inhibition of FLT3 phosphorylation and signaling in acute myeloid leukemia.

In 15% to 30% of patients with acute myeloid leukemia (AML), aberrant proliferation is a consequence of a juxtamembrane mutation in the FLT3 gene (FMS-like tyrosine kinase 3-internal tandem duplication [FLT3-ITD]), causing constitutive kinase activity. ABT-869 (a multitargeted receptor tyrosine kinase inhibitor) inhibited the phosphorylation of FLT3, STAT5, and ERK, as well as Pim-1 expression in MV-4-11 and MOLM-13 cells (IC(50) approximately 1-10 nM) harboring the FLT3-ITD. ABT-869 inhibited the proliferation of these cells (IC(50) = 4 and 6 nM, respectively) through the induction of apoptosis (increased sub-G(0)/G(1) phase, caspase activation, and PARP cleavage), whereas cells harboring wild-type (wt)-FLT3 were less sensitive. In normal human blood spiked with AML cells, ABT-869 inhibited phosphorylation of FLT3 (IC(50) approximately 100 nM), STAT5, and ERK, and decreased Pim-1 expression. In methylcellulose-based colony-forming assays, ABT-869 had no significant effect up to 1000 nM on normal hematopoietic progenitor cells, whereas in AML patient samples harboring both FLT3-ITD and wt-FLT3, ABT-869 inhibited colony formation (IC(50) = 100 and 1000 nM, respectively). ABT-869 dose-dependently inhibited MV-4-11 and MOLM-13 flank tumor growth, prevented tumor formation, regressed established MV-4-11 xenografts, and increased survival by 20 weeks in an MV-4-11 engraftment model. In tumors, ABT-869 inhibited FLT3 phosphorylation, induced apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]) and decreased proliferation (Ki67). ABT-869 is under clinical development for AML.

Calcium-dependent upregulation of E4BP4 expression correlates with glucocorticoid-evoked apoptosis of human leukemic CEM cells.

Glucocorticoid (GC)-evoked apoptosis of T-lymphoid cells is preceded by increases in the intracellular Ca2+ concentration ([Ca2+]i), which may contribute to apoptosis. This report demonstrates that GC-mediated upregulation of the bZIP transcriptional repressor gene, E4BP4, is dependent on [Ca2+]i levels, and correlates with GC-evoked apoptosis of GC-sensitive CEM-C7-14 cells. Calcium chelators EGTA and BAPTA reduced [Ca2+]i levels and protected CEM-C7-14 cells from Dex-evoked E4BP4 upregulation as well as apoptosis. In the GC-resistant sister clone, CEM-C1-15, Dex treatment did not induce [Ca2+]i levels, E4BP4 expression or apoptosis, however, the calcium ionophore A23187 restored Dex-evoked E4BP4 upregulation and apoptosis. CEM-C7-14 cells were more sensitive to GC-independent increases in [Ca2+]i levels by thapsigargin, and a corresponding increase in E4BP4 expression and cell death, compared to CEM-C1-15 cells, suggesting a direct correlation between [Ca2+]i levels, E4BP4 expression, and apoptosis.

Role of cyclic AMP response element binding protein in human leukemias.

Acute myeloid leukemia (AML) in adults has a 20% 5-year disease-free survival despite treatment with aggressive cytotoxic chemotherapy. Previous work from our laboratory demonstrated that the majority of patients with acute lymphoid and myeloid leukemia overexpress CREB in the bone marrow. CREB overexpression is associated with poor initial outcome of clinical disease in AML patients. CREB is a transcription factor that functions in glucose homeostasis, growth-factor-dependent cell survival, and memory. Signaling by hematopoietic growth factors, such as GM-CSF, results in activation of CREB and up-regulation of CREB target genes. To study its role in hematopoiesis, we overexpressed CREB in leukemia cell lines and in mice. CREB overexpression resulted in increased survival and proliferation of myeloid cells and blast-transformation of bone marrow progenitor cells from transgenic mice expressing CREB in the myeloid lineage. CREB transgenic mice also develop myeloproliferative disease after 1 year. Thus, CREB acts as a protooncogene to regulate hematopoiesis and contributes to the leukemia phenotype. Our results suggest that CREB-dependent pathways may serve as targets for directed therapies in leukemia in the future.

The role of CREB as a proto-oncogene in hematopoiesis.

Cyclic-AMP response element binding protein (CREB) is a transcription factor that functions in glucose homeostasis, growth-factor- dependent cell survival, proliferation and memory. Signaling by hematopoietic growth factors, such as GM-CSF, results in activation of CREB and upregulation of CREB target genes. Data from our laboratory shows that a majority of patients with acute lymphoid and myeloid leukemia overexpress CREB in the bone marrow. CREB overexpression is associated with poor initial outcome of clinical disease in AML patients. To study its role in hematopoiesis, we overexpressed CREB in leukemia cell lines and in mice. CREB overexpression resulted in increased survival and proliferation of myeloid cells and blast-transformation of bone marrow progenitor cells from transgenic mice expressing CREB in the myeloid lineage. CREB transgenic mice also develop myeloproliferative disease after one year. Thus, CREB acts as a proto-oncogene to regulate hematopoiesis and contributes to the leukemia phenotype. Our results suggest that CREB-dependent pathways may serve as targets for directed therapies in leukemia in the future.

The role of CREB as a proto-oncogene in hematopoiesis and in acute myeloid leukemia.

CREB is a transcription factor that functions in glucose homeostasis, growth factor-dependent cell survival, and memory. In this study, we describe a role of CREB in human cancer. CREB overexpression is associated with increased risk of relapse and decreased event-free survival. CREB levels are elevated in blast cells from patients with acute myeloid leukemia. To understand the role of CREB in leukemogenesis, we studied the biological consequences of CREB overexpression in primary human leukemia cells, leukemia cell lines, and transgenic mice. Our results demonstrate that CREB promotes abnormal proliferation and survival of myeloid cells in vitro and in vivo through upregulation of specific target genes. Thus, we report that CREB is implicated in myeloid cell transformation.

The role of cyclic-AMP binding protein (CREB) in leukemia cell proliferation and acute leukemias.

Leukemia is a result of accumulating genetic alterations. The collaboration of mutations that offer survival and proliferative signals, together with mutations that result in lack of differentiation, is thought to cause a leukemic phenotype. The cyclic-AMP Response Element Binding Protein (CREB) is a transcription factor that is known to be a downstream component of the GM-CSF and IL-3 signaling pathways. We previously showed that CREB is overexpressed in blast cells from patients with acute leukemias. In this paper, we review the role of CREB in hematopoiesis, cell proliferation and acute leukemias.

The role of p55CDC in cell cycle control and mammalian cell proliferation, differentiation, and apoptosis.

The p55CDC (cell division cycle) protein is a key regulator of the cell cycle. p55CDC is related to both the CDC20 and the CDH1 proteins in yeast. p55CDC has been shown to activate the ubiquitin ligase anaphase promoting complex (APC), which is involved in degradation of proteins that control mitosis. To define the role of p55CDC during the mammalian cell cycle, we overexpressed this protein in the murine myeloid cell line 32Dcl3. 32Dcl3 cells are an ideal model system because these cells can be induced to proliferate, differentiate, or activate cellular programs leading to apoptosis. Our work suggests that p55CDC participates in cell growth, maturation, and death. Thus, p55CDC may play a more diverse role in modulating cellular functions in addition to controlling the cell cycle.