Publications by authors named "Pulikkan J"

N-MYC (encoded by ) is a critical regulator of hematopoietic stem cell function. While the role of N-MYC deregulation is well established in neuroblastoma, the importance of N-MYC deregulation in leukemogenesis remains elusive. Here, we demonstrate that N-MYC is overexpressed in acute myeloid leukemia (AML) cells with chromosome inversion inv(16) and contributes to the survival and maintenance of inv(16) leukemia.

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Background: Indian cattle breeds (Bos indicus) are known for their remarkable adaptability to hot and humid climates, higher nutritious quality of milk, better disease tolerance, and greater ability to perform in poor feed compared to taurine cattle (Bos taurus). Distinct phenotypic differences are observed among the B. indicus breeds; however, the whole genome sequences were unavailable for these indigenous breeds.

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Adenosine-to-inosine RNA editing, which is catalyzed by adenosine deaminases acting on RNA (ADAR) family of enzymes, ADAR1 and ADAR2, has been shown to contribute to multiple cancers. However, other than the chronic myeloid leukemia blast crisis, relatively little is known about its role in other types of hematological malignancies. Here, we found that ADAR2, but not ADAR1 and ADAR3, was specifically downregulated in the core-binding factor (CBF) acute myeloid leukemia (AML) with t(8;21) or inv(16) translocations.

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The gut microbiota and its impact on health and nutrition in animals, including cattle has been of intense interest in recent times. Cattle, in particular indigenous varieties like Kasaragod Dwarf cow, have not received the due consideration given to other non-native cattle breeds, and the composition of their fecal microbiome is yet to be established. This study applied 16S rRNA high-throughput sequencing of fecal samples and compared the Kasaragod Dwarf with the highly prevalent Holstein crossbred cattle.

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The blood system serves as a key model for cell differentiation and cancer. It is orchestrated by precise spatiotemporal expression of crucial transcription factors. One of the key master regulators in the hematopoietic systems is PU.

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The core binding factor composed of CBFβ and RUNX subunits plays a critical role in most hematopoietic lineages and is deregulated in acute myeloid leukemia (AML). The fusion oncogene CBFβ-SMMHC expressed in AML with the chromosome inversion inv(16)(p13q22) acts as a driver oncogene in hematopoietic stem cells and induces AML. This review focuses on novel insights regarding the molecular mechanisms involved in CBFβ-SMMHC-driven leukemogenesis and recent advances in therapeutic approaches to target CBFβ-SMMHC in inv(16) AML.

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Acute myeloid leukemia (AML) is a high-risk malignancy characterized by a diverse spectrum of somatic genetic alterations. The mechanisms by which these mutations contribute to leukemia development and how this informs the use of targeted therapies is critical to improving outcomes for patients. Importantly, how to target loss-of-function mutations has been a critical challenge in precision medicine.

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Recently, dysbiosis in the human gut microbiome and shifts in the relative abundances of several bacterial species have been recognized as important factors in colorectal cancer (CRC). However, these studies have been carried out mainly in developed countries where CRC has a high incidence, and it is unclear whether the host-microbiome relationships deduced from these studies can be generalized to the global population. To test if the documented associations between the microbiome and CRC are conserved in a distinct context, we performed metagenomic and metabolomic association studies on fecal samples from 30 CRC patients and 30 healthy controls from two different locations in India, followed by a comparison of CRC data available from other populations.

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Autism spectrum disorder (ASD) is a severe neurodevelopmental or neuropsychiatric disorder with elusive etiology and obscure pathophysiology. Cognitive inabilities, impaired communication, repetitive behavior pattern, and restricted social interaction and communication lead to a debilitating situation in autism. The pattern of co-occurrence of medical comorbidities is most intriguing in autism, compared to any other neurodevelopmental disorders.

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Background: Metagenomic studies carried out in the past decade have led to an enhanced understanding of the gut microbiome in human health; however, the Indian gut microbiome has not been well explored. We analyzed the gut microbiome of 110 healthy individuals from two distinct locations (North-Central and Southern) in India using multi-omics approaches, including 16S rRNA gene amplicon sequencing, whole-genome shotgun metagenomic sequencing, and metabolomic profiling of fecal and serum samples.

Results: The gene catalogue established in this study emphasizes the uniqueness of the Indian gut microbiome in comparison to other populations.

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The fusion oncoprotein CBFβ-SMMHC, expressed in leukemia cases with chromosome 16 inversion, drives leukemia development and maintenance by altering the activity of the transcription factor RUNX1. Here, we demonstrate that CBFβ-SMMHC maintains cell viability by neutralizing RUNX1-mediated repression of MYC expression. Upon pharmacologic inhibition of the CBFβ-SMMHC/RUNX1 interaction, RUNX1 shows increased binding at three MYC distal enhancers, where it represses MYC expression by mediating the replacement of the SWI/SNF complex component BRG1 with the polycomb-repressive complex component RING1B, leading to apoptosis.

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Acute myeloid leukemia (AML) is a collection of hematologic malignancies with specific driver mutations that direct the pathology of the disease. The understanding of the origin and function of these mutations at early stages of transformation is critical to understand the etiology of the disease and for the design of effective therapies. The chromosome inversion inv(16) is thought to arise as a founding mutation in a hematopoietic stem cell (HSC) to produce preleukemic HSCs (preL-HSCs) with myeloid bias and differentiation block, and predisposed to AML.

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Autism spectrum disorder (ASD) is a term associated with a group of neurodevelopmental disorders. The etiology of ASD is not yet completely understood; however, a disorder in the gut-brain axis is emerging as a prominent factor leading to autism. To identify the taxonomic composition and markers associated with ASD, we compared the fecal microbiota of 30 ASD children diagnosed using Childhood Autism Rating Scale (CARS) score, DSM-5 approved AIIMS-modified INCLEN Diagnostic Tool for Autism Spectrum Disorder (INDT-ASD), and Indian Scale for Assessment of Autism (ISAA) tool, with family-matched 24 healthy children from Indian population using next-generation sequencing (NGS) of 16S rRNA gene amplicon.

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The gene encoding the RUNX1 transcription factor is mutated in a subset of T-cell acute lymphoblastic leukemia (T-ALL) patients, and mutations are associated with a poor prognosis. These mutations cluster in the DNA-binding Runt domain and are thought to represent loss-of-function mutations, indicating that RUNX1 suppresses T-cell transformation. RUNX1 has been proposed to have tumor suppressor roles in T-cell leukemia homeobox 1/3-transformed human T-ALL cell lines and NOTCH1 T-ALL mouse models.

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Myeloid master regulator CCAAT enhancer-binding protein alpha (C/EBPα) is deregulated by multiple mechanisms in leukemia. Inhibition of C/EBPα function plays pivotal roles in leukemogenesis. While much is known about how C/EBPα orchestrates granulopoiesis, our understanding of molecular transformation events, the role(s) of cooperating mutations and clonal evolution during C/EBPα deregulation in leukemia remains elusive.

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Transcription factors have traditionally been viewed with skepticism as viable drug targets, but they offer the potential for completely novel mechanisms of action that could more effectively address the stem cell like properties, such as self-renewal and chemo-resistance, that lead to the failure of traditional chemotherapy approaches. Core binding factor is a heterodimeric transcription factor comprised of one of 3 RUNX proteins (RUNX1-3) and a CBFβ binding partner. CBFβ enhances DNA binding of RUNX subunits by relieving auto-inhibition.

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Acute myeloid leukemia (AML) is the most common form of adult leukemia. The transcription factor fusion CBFβ-SMMHC (core binding factor β and the smooth-muscle myosin heavy chain), expressed in AML with the chromosome inversion inv(16)(p13q22), outcompetes wild-type CBFβ for binding to the transcription factor RUNX1, deregulates RUNX1 activity in hematopoiesis, and induces AML. Current inv(16) AML treatment with nonselective cytotoxic chemotherapy results in a good initial response but limited long-term survival.

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Acute myeloid leukemia (AML) results from the activity of driver mutations that deregulate proliferation and survival of hematopoietic stem cells (HSCs). The fusion protein CBFβ-SMMHC impairs differentiation in hematopoietic stem and progenitor cells and induces AML in cooperation with other mutations. However, the combined function of CBFβ-SMMHC and cooperating mutations in preleukemic expansion is not known.

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Oncogenic mutations in components of cytokine signaling pathways elicit ligand-independent activation of downstream signaling, enhancing proliferation and survival in acute myeloid leukemia (AML). The myeloproliferative leukemia virus oncogene, MPL, a homodimeric receptor activated by thrombopoietin (THPO), is mutated in myeloproliferative disorders but rarely in AML. Here we show that wild-type MPL expression is increased in a fraction of human AML samples expressing RUNX1-ETO, a fusion protein created by chromosome translocation t(8;21), and that up-regulation of Mpl expression in mice induces AML when coexpressed with RUNX1-ETO.

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The transcription factor, CCAAT enhancer binding protein alpha (C/EBPα), is crucial for granulopoiesis and is deregulated by various mechanisms in acute myeloid leukemia (AML). Mutations in the CEBPA gene are reported in 10% of human patients with AML. Even though the C/EBPα mutants are known to display distinct biologic function during leukemogenesis, the molecular basis for this subtype of AML remains elusive.

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The transcription factor CCAAT enhancer-binding protein alpha (C/EBPalpha) has an important role in granulopoiesis. The tumor suppressor function of C/EBPalpha is shown by the findings that loss of expression or function of C/EBPalpha in leukemic blasts contributes to a block in myeloid cell differentiation and to leukemia. C/EBPalpha mutations are found in around 9% of acute myeloid leukemia (AML) patients.

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Transcription factor CCAAT enhancer binding protein alpha (C/EBPalpha) is essential for granulopoiesis and its function is deregulated in leukemia. Inhibition of E2F1, the master regulator of cell-cycle progression, by C/EBPalpha is pivotal for granulopoiesis. Recent studies show microRNA-223 (miR-223), a transcriptional target of C/EBPalpha, as a critical player during granulopoiesis.

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CCAAT/enhancer-binding protein alpha (C/EBPalpha) is a critical regulator for early myeloid differentiation. Mutations in C/EBPalpha occur in 10% of patients with acute myeloid leukemia (AML), leading to the expression of a 30-kDa dominant-negative isoform (C/EBPalphap30). In the present study, using a global proteomics approach to identify the target proteins of C/EBPalphap30, we show that Ubc9, an E2-conjugating enzyme essential for sumoylation, is increased in its expression when C/EBPalphap30 is induced.

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