Non-enzymatic methods for isolation of stromal vascular fraction and adipose-derived stem cells: A systematic review.

BACKGROUND: Adipose-derived stem cells (ADSCs) and the stromal vascular fraction (SVF) have garnered substantial interest in regenerative medicine due to their potential to treat a wide range of conditions. Traditional enzymatic methods for isolating these cells face challenges such as high costs, lengthy processing time, and regu-latory complexities. AIM: This systematic review aimed to assess the efficacy and practicality of non-enzymatic, mechanical methods for isolating SVF and ADSCs, comparing these to conventional enzymatic approaches. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a comprehensive literature search was conducted across multiple databases. Studies were selected based on inclusion criteria focused on non-enzymatic isolation methods for SVF and ADSCs from adipose tissue. The risk of bias was assessed, and a qualitative synthesis of findings was performed due to the methodological heterogeneity of the included studies. RESULTS: Nineteen studies met the inclusion criteria, highlighting various mechanical techniques such as centrifugation, vortexing, and ultrasonic cavitation. The review identified significant variability in cell yield and viability, and the integrity of isolated cells across different non-enzymatic methods compared to enzymatic procedures. Despite some advantages of mechanical methods, including reduced processing time and avoidance of enzymatic reagents, the evidence suggests a need for optimization to match the cell quality and therapeutic efficacy achievable with enzymatic isolation. CONCLUSION: Non-enzymatic, mechanical methods offer a promising alternative to enzymatic isolation of SVF and ADSCs, potentially simplifying the isolation process and reducing regulatory hurdles. However, further research is necessary to standardize these techniques and ensure consistent, high-quality cell yields for clinical applications. The development of efficient, safe, and reproducible non-enzymatic isolation methods could significantly advance the field of regenerative medicine.

Application of Classroom Assessment Techniques in Medical Education: Results From the Community Medicine Teaching and Learning Experience.

Introduction Efficient delivery of medical education (ME) is crucial to improving the standards of future physicians or clinicians. India has been experiencing an enormous increase in medical colleges and student admissions into medicine. This has resulted in overcrowding and compromised the student-to-teacher ratio. Conversely, students and teachers face difficulties with learning and teaching, respectively. Classroom assessment techniques (CATs) offer an egalitarian and productive approach to student learning and evaluation. This study was conducted to understand the role of CATs in improving student learning and motivation during community medicine lectures. Further, this study assessed the classroom teaching and learning (TL) process. Method This study included 100 third-year medical students pursuing a Bachelor of Medicine and Bachelor of Surgery (MBBS) and 12 faculty members working at Great Eastern Medical School and Hospital (GEMS&H), Srikakulam, India. To facilitate learning and boost motivation, this study applied three CATs including a one-minute paper (OMP), muddiest point (MP), and student-generated test questions (SGTQs). After two months of applying CATs, the teachers and students were asked for feedback on their experiences. The data generated from feedback forms were tabulated and analyzed. Results According to 76% (76/100) of students, these strategies have stimulated their interest in learning community medicine. Besides, 64% (64/100) of students believed utilizing these strategies would improve their exam outcomes. Further, 77% (77/100) of students believed these methods must be applied in subsequent lessons. About 68% (68/100) of students thought other subject teachers should also employ these strategies. Of the 12 faculty members included in the study, they mostly liked the OMP (5; 41.66%) and MP technique (5; 41.66%). Conclusions Teachers and students have highly welcomed the utility of CATs to improve learning in community medicine. Of the three CATs applied, the OMP was the most popular with students, and teachers agreed that using OMP in the classroom along with MP would be beneficial. Most students and teachers were enthusiastic about employing additional TL strategies like CATs.

Valorization of cashew nut testa phenolics through nano-complexes stabilized with whey protein isolate and ß-cyclodextrin: Characterization, anti-oxidant activity, stability and in vitro release.

Cashew nut testa (CNT) is an underutilized cashew by-product rich in polyphenols. The applications of CNT are limited due to its astringency, less solubility, and instability of polyphenols during the processing. Nanoencapsulation was used to overcome these limitations. ß-cyclodextrin alone and in combination with whey protein isolate (WPI) was used for nano-complex preparation. The WPI/CD-CNT nano-complex powder showed higher encapsulation efficiency (86.9%) and yield (70.5-80%) compared to CD-CNT powder. Both the spray-dried powders showed improved thermal stability, higher solubility (97%), less moisture content, and increased DPPH and ABTS radical scavenging activities indicating potential food and agricultural applications. In addition, the nano-complex powders showed a controlled release of core bio-actives under gastric and intestinal pH compared to the non-encapsulated CNT phenolic extract. Degradation kinetics studies of the CNT extract after thermal and light treatments were also discussed. Both the nano-complexes showed high stability under light and thermal treatment. The results suggest that valorization of CNT can be done through nano-complex preparation and WPI and ß-CD are efficient carrier materials for the encapsulation of polyphenols with potential applications in food and agriculture.

Serum Activities of Paraoxonase 1 (PON1) in Predicting Liver Damage Among Patients Diagnosed With Hepatocellular Carcinoma: A Case-Control Study.

Introduction Hepatocellular carcinoma (HCC) is one of the most common cancers in the world and unless diagnosed timely has limited options for treatment. Paraoxonase (PON) is a glycosylated protein that has been implicated in antioxidant and other biochemical functions. Paraoxonase 1 (PON1) is an esterase associated with high-density lipoprotein (HDL) particles. The present study was carried out to assess the PON1 activity and compare it with the standard liver function tests (LFTs) in assessing the predictability of liver damage among patients diagnosed with HCC. Methods This case-control study was carried out in the Department of Biochemistry attached to Great Eastern Medical School and Hospital, Srikakulam, Andhra Pradesh. Serum PON1 activities and LFTs like total bilirubin, direct bilirubin, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), total protein, and albumin were estimated in 30 patients diagnosed with HCC and 30 healthy persons. All the parameters were estimated using standard biochemical methods. The data was analyzed using GraphPad Prism version 6.0 (GraphPad Software, Inc). A probability (p) value <0.05 was considered to be statistically significant. Receiver operating characteristic curve (ROC) analysis was performed to assess the area under the curve (AUC) for accuracy, sensitivity, specificity, and diagnostic efficiency. Results The serum activities of PON1 had identical sensitivity (70%) to albumin (70%) and were superior to other tested parameters. Additionally, PON1 activities showed lower specificity (86.67%) than the other tested parameters. ROC analysis showed increased diagnostic efficacy (DE) of PON1 (DE=78.3%; p<0.0001) when compared with total bilirubin (DE=76.6%; p=0.0039), direct bilirubin (DE=74.9%; p=0.04), ALT (DE=73.30%; p=0.0006), and total protein (DE=71.6%; p=0.0005). However, the DE of PON1 was comparable with AST (DE=81.60%; p<0.0001), ALP (DE=79.9%; p<0.0001), and albumin (DE=83.30%, p<0.0001). Conclusions Serum activities of PON1 could be used as a diagnostic marker for assessing liver damage among HCC patients.

A noncanonical enzymatic function of PIWIL4 maintains genomic integrity and leukemic growth in AML.

RNA-binding proteins (RBPs) form a large and diverse class of factors, many members of which are overexpressed in hematologic malignancies. RBPs participate in various processes of messenger RNA (mRNA) metabolism and prevent harmful DNA:RNA hybrids or R-loops. Here, we report that PIWIL4, a germ stem cell-associated RBP belonging to the RNase H-like superfamily, is overexpressed in patients with acute myeloid leukemia (AML) and is essential for leukemic stem cell function and AML growth, but dispensable for healthy human hematopoietic stem cells. In AML cells, PIWIL4 binds to a small number of known piwi-interacting RNA. Instead, it largely interacts with mRNA annotated to protein-coding genic regions and enhancers that are enriched for genes associated with cancer and human myeloid progenitor gene signatures. PIWIL4 depletion in AML cells downregulates the human myeloid progenitor signature and leukemia stem cell (LSC)-associated genes and upregulates DNA damage signaling. We demonstrate that PIWIL4 is an R-loop resolving enzyme that prevents R-loop accumulation on a subset of AML and LSC-associated genes and maintains their expression. It also prevents DNA damage, replication stress, and activation of the ATR pathway in AML cells. PIWIL4 depletion potentiates sensitivity to pharmacological inhibition of the ATR pathway and creates a pharmacologically actionable dependency in AML cells.

Immunophenotypical profiling of myeloid neoplasms with erythroid predominance using mass cytometry (CyTOF).

Acute erythroid leukemia (AEL) is a disease continuum between Myelodysplastic syndrome (MDS) and Acute myeloid leukemia (AML) with the cellular hallmark of uncontrolled proliferation and impaired differentiation of erythroid progenitor cells. First described by Giovanni di Guglielmo in 1917 AEL accounts for less than 5% of all de novo AML cases. There have been efforts to characterize AEL at a molecular level, describing recurrent alterations in TP53, NPM1 and FLT3 genes. A genomic analysis of AEL cases confirmed its complexity. Despite these advances, the biology underlying erythroid proliferations remains unclear and the prognosis is dismal with a median survival of only 3 months for pure erythroid leukemia (PEL). Marker combinations suitable for the identification and characterization of leukemic stem cell (LSC) candidates, monitoring measurable residual disease (MRD) during chemotherapy treatment and the development of innovative targeted therapies are missing. Here, we developed a mass cytometry panel for an in-depth characterization of erythroid and myeloid blast cell populations from human AEL bone marrow samples in comparison to other AML subtypes and healthy counterparts. A total of 8 AEL samples were analyzed and compared to 28 AML samples from different molecular subtypes, healthy bone marrow counterparts (n = 5) and umbilical cord blood (n = 6) using high-dimensional mass cytometry. Identification of erythroid and myeloid blast populations in high-dimensional mass cytometry data enabled a refined view on erythroblast differentiation stages present in AEL erythroid blasts and revealed immunophenotypical profiles specific to AEL. Profiling of phenotypic LSCs revealed aberrant erythroid marker expression in the CD34+ CD38- stem cell compartment. In addition, the identification of novel candidate surface marker combinations and aberrancies might enhance clinical diagnostics of AEL. We present a high-parameter mass cytometry approach feasible for immunophenotypical analysis of blast and stem cell populations in myeloid neoplasms with erythroid predominance laying the foundation for more precise experimental approaches in the future.

TET3 promotes AML growth and epigenetically regulates glucose metabolism and leukemic stem cell associated pathways.

Acute myeloid leukemia (AML) is considered a poor prognosis malignancy where patients exhibit altered glucose metabolism and stem cell signatures that contribute to AML growth and maintenance. Here, we report that the epigenetic factor, Ten-Eleven Translocation 3 (TET3) dioxygenase is overexpressed in AML patients and functionally validated human leukemic stem cells (LSCs), is required for leukemic growth by virtue of its regulation of glucose metabolism in AML cells. In human AML cells, TET3 maintains 5-hydroxymethylcytosine (5hmC) epigenetic marks and expression of early myeloid progenitor program, critical glucose metabolism and STAT5A signaling pathway genes, which also positively correlate with TET3 expression in AML patients. Consequently, TET3 depletion impedes hexokinase activity and L-Lactate production in AML cells. Conversely, overexpression of TET3 in healthy human hematopoietic stem progenitors (HSPCs) upregulates the expression of glucose metabolism, STAT5A signaling and AML associated genes, and impairs normal HSPC lineage differentiation in vitro. Finally, TET3 depletion renders AML cells highly sensitive to blockage of the TET3 downstream pathways glycolysis and STAT5 signaling via the combination of 2-Deoxy-D-glucose and STAT5 inhibitor which preferentially targets AML cells but spares healthy CD34+ HSPCs.

Development and validation of headspace Solid-Phase microextraction coupled with gas chromatography (HS-SPME-GC) method for the analysis of zingiber zerumbet L.

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography (GC-FID) was explored to determine the fingerprinting characteristic of Zingiber zerumbet L. volatiles to differentiate between different ginger species. The effect of different fibers [polydimethylsiloxane (PDMS, 7 µm), polyacrylate (PA, 85 µm)], different temperature and time on the HS-SPME-GC was investigated by using response surface methodology coupled with full factorial experimental design. The area percentage of the major sesquiterpenes (Zerumbone and α-humulene) were 56.3 ± 4.7% and 47.5 ± 27.2% with PA fiber, respectively at optimum condition of 70 °C and 30 min. Validation of the developed HS-SPME-GC method with limits of detection and quantification for zerumbone was 0.09 and 0.28 µg/g, respectively, demonstrating the suitable sensitivity of HS-SPME-GC method for the quantification of sesquiterpenes. Therefore, the simplicity of HS-SPME-GC makes it a convenient tool for qualitative and quantitative comparison of different ginger species targeting at the marker sesquiterpene molecule, zerumbone.

Characterization of volatile components from ginger plant at maturity and its value addition to ice cream.

Ginger is widely consumed spice across the globe and especially in Asian countries routinely employed in various culinary preparations. Ginger possesses many distinct bioactive molecules, have shown marked therapeutic benefits. The ginger aroma is mainly due to the volatile compounds present in the rhizome. The current paper focuses on comparison of volatile constituents present in different plant parts of ginger concerning maturity and effect of incorporation of freeze-dried ginger extract into ice cream. Fresh ginger was collected for 5 months (every 30 days) and analysed for their differences in volatile composition with respect to maturity. Later ginger juice was extracted from fresh ginger and freeze-dried. Freeze-dried ginger powder was incorporated into icecream at various concentrations and studied the microbiological and sensory quality. Results from GC-MS profiles revealed the dominance of sesquiterpenes. Zingiberene a major volatile compound, increased from 2.52 to 18.15% with an increase in maturity days, whereas ar-curcumin decreased from 12.58 to 3.84%. The freeze-dried ginger powder yielded 10.2 ± 0.1% of oleoresin, which consists of 3.6 ± 0.2% of 6-gingerol. The value added ice cream with gingerols had the desirable sensory attributes with the novelty of natural ginger flavour. Icecream was pleasant, with attractive visual appeal, which is an essential determinant for consumer acceptance. The microbial quality of the ice cream was compared with the FSSAI standards, and the study was found to be within acceptable limits.

Somatostatin receptor mediated targeting of acute myeloid leukemia by photodynamic metal complexes for light induced apoptosis.

Acute myeloid leukemia (AML) is characterized by relapse and treatment resistance in a major fraction of patients, underlining the need of innovative AML targeting therapies. Here we analysed the therapeutic potential of an innovative biohybrid consisting of the tumor-associated peptide somatostatin and the photosensitizer ruthenium in AML cell lines and primary AML patient samples. Selective toxicity was analyzed by using CD34 enriched cord blood cells as control. Treatment of OCI AML3, HL60 and THP1 resulted in a 92, and 99 and 97% decrease in clonogenic growth compared to the controls. Primary AML cells demonstrated a major response with a 74 to 99% reduction in clonogenicity in 5 of 6 patient samples. In contrast, treatment of CD34+ CB cells resulted in substantially less reduction in colony numbers. Subcellular localization assays of RU-SST in OCI-AML3 cells confirmed strong co-localization of RU-SST in the lysosomes compared to the other cellular organelles. Our data demonstrate that conjugation of a Ruthenium complex with somatostatin is efficiently eradicating LSC candidates of patients with AML. This indicates that receptor mediated lysosomal accumulation of photodynamic metal complexes is a highly attractive approach for targeting AML cells.

Glutathione peroxidase 4 and vitamin E control reticulocyte maturation, stress erythropoiesis and iron homeostasis.

Glutathione peroxidase 4 (GPX4) is unique as it is the only enzyme that can prevent detrimental lipid peroxidation in vivo by reducing lipid peroxides to the respective alcohols thereby stabilizing oxidation products of unsaturated fatty acids. During reticulocyte maturation, lipid peroxidation mediated by 15-lipoxygenase in humans and rabbits and by 12/15-lipoxygenase (ALOX15) in mice was considered the initiating event for the elimination of mitochondria but is now known to occur through mitophagy. Yet, genetic ablation of the Alox15 gene in mice failed to provide evidence for this hypothesis. We designed a different genetic approach to tackle this open conundrum. Since either other lipoxygenases or non-enzymatic autooxidative mechanisms may compensate for the loss of Alox15, we asked whether ablation of Gpx4 in the hematopoietic system would result in the perturbation of reticulocyte maturation. Quantitative assessment of erythropoiesis indices in the blood, bone marrow (BM) and spleen of chimeric mice with Gpx4 ablated in hematopoietic cells revealed anemia with an increase in the fraction of erythroid precursor cells and reticulocytes. Additional dietary vitamin E depletion strongly aggravated the anemic phenotype. Despite strong extramedullary erythropoiesis reticulocytes failed to mature and accumulated large autophagosomes with engulfed mitochondria. Gpx4-deficiency in hematopoietic cells led to systemic hepatic iron overload and simultaneous severe iron demand in the erythroid system. Despite extremely high erythropoietin and erythroferrone levels in the plasma, hepcidin expression remained unchanged. Conclusively, perturbed reticulocyte maturation in response to Gpx4 loss in hematopoietic cells thus causes ineffective erythropoiesis, a phenotype partially masked by dietary vitamin E supplementation.

A non-edible waste as a potential sorptive media for removal of herbicide from the watershed.

A non-edible waste, from biodiesel processing industry is being turned to carbonaceous material (biochar) using slow pyrolysis. The material was found to be amorphous with hydroxyl, methyl, carbonyl and carboxyl functional groups onto the surface. The influencing parameters, namely adsorbate concentration (0.05-5 mg/l), biochar loading (0.02-0.4 g), pH(3-12) and particle sizes (0.03-0.13 mm) were studied to observe the effect on the sorption of simazine using biochar. A multivariate optimization using central composite design in response surface methodology was performed employing desirability function. The optimized biosorption efficiency (B%) and capacity qe was found to be 91.98 % and 0.83 mg/g respectively with the optimized parameters as 3.76 mg/l of adsorbate concentration, 0.12 g of biochar loading, pH of 5.26 and 0.0535 mm of particle size. The simazine adsorption phenomena were found to be multilayer heterogeneous sorption based on Langmuir and Freundlich models. The kinetics investigation shows that chemisorption was involved for the transfer of simazaine to the surface of biochar with three distinct intra particulate diffusional zones. An adsorption process requires activation energy of 11.27 kJ/mol and the negative magnitude of ΔH* indicates the exothermicity involved in the process.

The ParaHox gene Cdx4 induces acute erythroid leukemia in mice.

Acute erythroid leukemia (AEL) is a rare and aggressive form of acute leukemia, the biology of which remains poorly understood. Here we demonstrate that the ParaHox gene CDX4 is expressed in patients with acute erythroid leukemia, and that aberrant expression of Cdx4 induced homogenously a transplantable acute erythroid leukemia in mice. Gene expression analyses demonstrated upregulation of genes involved in stemness and leukemogenesis, with parallel downregulation of target genes of Gata1 and Gata2 responsible for erythroid differentiation. Cdx4 induced a proteomic profile that overlapped with a cluster of proteins previously defined to represent the most primitive human erythroid progenitors. Whole-exome sequencing of diseased mice identified recurrent mutations significantly enriched for transcription factors involved in erythroid lineage specification, as well as TP53 target genes partly identical to the ones reported in patients with AEL. In summary, our data indicate that Cdx4 is able to induce stemness and inhibit terminal erythroid differentiation, leading to the development of AEL in association with co-occurring mutations.

A pilot study on the effects of direct contact of two different surgical burs on the cadaveric lingual nerve.

The lingual guttering technique for third molar surgery carries the risk of injury to the lingual nerve if the surgical bur comes into direct contact with it. This study investigated the extent of nerve injury caused by two different burs, a tungsten carbide bur and the Dentium implant bur; the latter is designed to be soft tissue friendly. This study also examined whether ultrasound and magnetic resonance imaging are able to detect any injury inflicted. This cadaveric research involved subjecting 12 lingual nerves to the drilling effect of two different burs at two different speeds. The amount of damage caused was measured using different imaging modalities to assess their ability to detect the injury inflicted. At high speed, the Dentium bur caused a deeper and wider laceration than the carbide bur. At low speed, the laceration depths and widths caused by the two burs did not differ significantly. Ultrasound scanning was able to detect the nerve laceration at damaged sites observed using optical coherence tomography. Thus, a carbide bur (at low speed) would be preferable for lingual bone guttering, as it causes less laceration to the lingual nerve. In the event of a suspected injury, ultrasound scanning would provide an objective evaluation of the amount of nerve damage in vivo.

Mitochondria Targeted Protein-Ruthenium Photosensitizer for Efficient Photodynamic Applications.

Organelle-targeted photosensitization represents a promising approach in photodynamic therapy where the design of the active photosensitizer (PS) is very crucial. In this work, we developed a macromolecular PS with multiple copies of mitochondria-targeting groups and ruthenium complexes that displays highest phototoxicity toward several cancerous cell lines. In particular, enhanced anticancer activity was demonstrated in acute myeloid leukemia cell lines, where significant impairment of proliferation and clonogenicity occurs. Finally, attractive two-photon absorbing properties further underlined the great significance of this PS for mitochondria targeted PDT applications in deep tissue cancer therapy.

Controlled stem cell amplification by HOXB4 depends on its unique proline-rich region near the N terminus.

There is high interest in understanding the mechanisms that drive self-renewal of stem cells. HOXB4 is one of the few transcription factors that can amplify long-term repopulating hematopoietic stem cells in a controlled way. Here we show in mice that this characteristic of HOXB4 depends on a proline-rich sequence near the N terminus, which is unique among HOX genes and highly conserved in higher mammals. Deletion of this domain substantially enhanced the oncogenicity of HOXB4, inducing acute leukemia in mice. Conversely, insertion of the domain into Hoxa9 impaired leukemogenicity of this homeobox gene. These results indicate that proline-rich stretches attenuate the potential of stem cell active homeobox genes to acquire oncogenic properties.

VENTX induces expansion of primitive erythroid cells and contributes to the development of acute myeloid leukemia in mice.

Homeobox genes are key regulators in normal and malignant hematopoiesis. The human Vent-like homeobox gene VENTX, a putative homolog of the Xenopus laevis Xvent-2 gene, was shown to be highly expressed in normal myeloid cells and in patients with acute myeloid leukemia. We now demonstrate that constitutive expression of VENTX suppresses expression of genes responsible for terminal erythroid differentiation in normal CD34+ stem and progenitor cells. Transplantation of bone marrow progenitor cells retrovirally engineered to express VENTX caused massive expansion of primitive erythroid cells and partly acute erythroleukemia in transplanted mice. The leukemogenic potential of VENTX was confirmed in the AML1-ETO transplantation model, as in contrast to AML1-ETO alone co-expression of AML1-ETO and VENTX induced acute myeloid leukemia, partly expressing erythroid markers, in all transplanted mice. VENTX was highly expressed in patients with primary human erythroleukemias and knockdown of VENTX in the erythroleukemic HEL cell line significantly blocked cell growth. In summary, these data indicate that VENTX is able to perturb erythroid differentiation and to contribute to myeloid leukemogenesis when co-expressed with appropriate AML oncogenes and point to its potential significance as a novel therapeutic target in AML.

Efficacy of Standardized Extract of Bacopa monnieri (Bacognize®) on Cognitive Functions of Medical Students: A Six-Week, Randomized Placebo-Controlled Trial.

Rationale. Bacopa monnieri, popularly known as Brahmi, has been traditionally used in Ayurveda since ages for its memory enhancing properties. However, data on placebo-controlled trial of Bacopa monnieri on intellectual sample is scarce. Hence this study was planned to evaluate the effect of Bacopa monnieri on memory of medical students for six weeks. Objective. To evaluate the efficacy of Bacopa monnieri on memory of medical students with six weeks' administration. Method and Material. This was a randomized double blind placebo-controlled noncrossover, parallel trial. Sixty medical students of either gender from second year of medical school, third term, regular batch, were enrolled from Government Medical College, Nagpur, India. Baseline biochemical and memory tests were done. The participants were randomly divided in two groups to receive either 150 mg of standardized extract of Bacopa monnieri (Bacognize) or matching placebo twice daily for six weeks. All baseline investigations were repeated at the end of the trial. Students were followed up for 15 days after the intervention. Results. Statistically significant improvement was seen in the tests relating to the cognitive functions with use of Bacopa monnieri. Blood biochemistry also showed a significant increase in serum calcium levels (still within normal range).

MEIS2 Is an Oncogenic Partner in AML1-ETO-Positive AML.

Homeobox genes are known to be key factors in leukemogenesis. Although the TALE family homeodomain factor Meis1 has been linked to malignancy, a role for MEIS2 is less clear. Here, we demonstrate that MEIS2 is expressed at high levels in patients with AML1-ETO-positive acute myeloid leukemia and that growth of AML1-ETO-positive leukemia depends on MEIS2 expression. In mice, MEIS2 collaborates with AML1-ETO to induce acute myeloid leukemia. MEIS2 binds strongly to the Runt domain of AML1-ETO, indicating a direct interaction between these transcription factors. High expression of MEIS2 impairs repressive DNA binding of AML1-ETO, inducing increased expression of genes such as the druggable proto-oncogene YES1. Collectively, these data describe a pivotal role for MEIS2 in AML1-ETO-induced leukemia.