Novel FOXM1 inhibitor STL001 sensitizes human cancers to a broad-spectrum of cancer therapies

Forkhead box protein M1 (FOXM1) is often overexpressed in human cancers and strongly associated with therapy resistance and less good patient survival. The chemotherapy options for patients with the most aggressive types of solid cancers remain very limited because of the acquired drug resistance, making the therapy less effective. NPM1 mutation through the inactivation of FOXM1 via FOXM1 relocalization to the cytoplasm confers more favorable treatment outcomes for AML patients, confirming FOXM1 as a crucial target to overcome drug resistance. Pharmacological inhibition of FOXM1 could be a promising approach to sensitize therapy-resistant cancers. Here, we explore a novel FOXM1 inhibitor STL001, a first-generation modification drug of our previously reported FOXM1 inhibitor STL427944. STL001 preserves the mode of action of the STL427944; however, STL001 is up to 50 times more efficient in reducing FOXM1 activity in a variety of solid cancers. The most conventional cancer therapies studied here induce FOXM1 overexpression in solid cancers. The therapy-induced FOXM1 overexpression may explain the failure or reduced efficacy of these drugs in cancer patients. Interestingly, STL001 increased the sensitivity of cancer cells to conventional cancer therapies by suppressing both the high-endogenous and drug-induced FOXM1. Notably, STL001 does not provide further sensitization to FOXM1-KD cancer cells, suggesting that the sensitization effect is conveyed specifically through FOXM1 suppression. RNA-seq and gene set enrichment studies revealed prominent suppression of FOXM1-dependent pathways and gene ontologies. Also, gene regulation by STL001 showed extensive overlap with FOXM1-KD, suggesting a high selectivity of STL001 toward the FOXM1 regulatory network. A completely new activity of FOXM1, mediated through steroid/cholesterol biosynthetic process and protein secretion in cancer cells was also detected. Collectively, STL001 offers intriguing translational opportunities as combination therapies targeting FOXM1 activity in a variety of human cancers driven by FOXM1.

[WITHDRAWN] Novel FOXM1 inhibitor STL001 sensitizes human cancers to a broad-spectrum of cancer therapies

The full text of this preprint has been withdrawn by the authors while they make corrections to the work. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

Small-molecule inhibitors targeting FOXM1: Current challenges and future perspectives in cancer treatments

Forkhead box (FOX) protein M1 (FOXM1) is a critical proliferation-associated transcription factor (TF) that is aberrantly overexpressed in the majority of human cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in, cell proliferation, cell migration, invasion, angiogenesis and metastasis. The FOXM1 as a TF directly or indirectly regulates the expression of several target genes whose dysregulation is associated with almost all hallmarks of cancer. Moreover, FOXM1 expression is associated with chemoresistance to different anti-cancer drugs. Several studies have confirmed that suppression of FOXM1 enhanced the drug sensitivity of various types of cancer cells. Current data suggest that small molecule inhibitors targeting FOXM1 in combination with anticancer drugs may represent a novel therapeutic strategy for chemo-resistant cancers. In this review, we discuss the clinical utility of FOXM1, further, we summarize and discuss small-molecule inhibitors targeting FOXM1 and categorize them according to their mechanisms of targeting FOXM1. Despite great progress, small-molecule inhibitors targeting FOXM1 face many challenges, and we present here all small-molecule FOXM1 inhibitors in different stages of development. We discuss the current challenges and provide insights on the future application of FOXM1 inhibition to the clinic.

Role of Long Non-Coding RNAs in Human-Induced Pluripotent Stem Cells Derived Megakaryocytes: A p53, HOX Antisense Intergenic RNA Myeloid 1, and miR-125b Interaction Study

Megakaryocytes (MKs) are rare polyploid cells found in the bone marrow and produce platelets. Platelets are small cell fragments that are essential during wound healing and vascular hemostasis. In vitro differentiation of MKs from human-induced pluripotent stem cell-derived CD34⁺ hematopoietic stem cells (hiPSC-HSCs) could provide an alternative treatment option for thrombocytopenic patients as a platelet source. In this approach, we developed a method to produce functional MKs from hiPSC-HSCs using a xeno-free and feeder-free condition and minimize the variation and risk from animal-derived products in cell culture. We have also investigated the genome-wide expression as well as functional significance of long noncoding RNAs (lncRNAs) in hiPSC-HSC-derived MKs to get insight into MK biology. We have performed lncRNAs expression profiling by using the Human LncProfilers qPCR Array Kit and identified 26 differentially regulated lncRNAs in hiPSC-HSC-derived MKs as compared with those in hiPSC-HSCs. HOX antisense intergenic RNA myeloid 1 (HOTAIRM1) was the most highly upregulated lncRNA in hiPSC-HSC-derived MKs and phorbol 12-myristate 13-acetate (PMA)-induced megakaryocytic-differentiating K562 cells. Furthermore, we have studied the potential mechanism of HOTAIRM1 based on the interactions between HOTAIRM1, p53, and miR-125b in PMA-induced K562 cells. Our results demonstrated that during MK maturation, HOTAIRM1 might be associated with the transcriptional regulation of p53 via acting as a decoy for miR-125b. Thus, the interaction between HOTAIRM1, p53, and miR-125b is likely involved in controlling cell cycling (cyclin D1), reactive oxygen species production, and apoptosis to support terminal maturation of MKs. SIGNIFICANCE STATEMENT: In vitro generation of megakaryocytes (MKs) from human-induced pluripotent stem cell-derived hematopoietic stem cells (hiPSC-HSCs) could provide an alternative source of platelets for treating thrombocytopenic patients. This study has investigated the functional significance of long non-coding RNAs in hiPSC-HSC-derived MKs, which remains unclear. This study's findings suggest that the regulatory role of HOX antisense intergenic RNA myeloid 1 (HOTAIRM1) in p53-mediated regulation of cyclin D1 during megakaryocytopoiesis is to promote MK maturation by decoying miR-125b.

Megakaryoblastic leukemia: a study on novel role of clinically significant long non-coding RNA signatures in megakaryocyte development during treatment with phorbol ester

Acute megakaryocytic leukemia (AMKL) is one of the rarest sub-types of acute myeloid leukemia (AML). AMKL is characterized by high proliferation of megakaryoblasts and myelofibrosis of bone marrow, this disease is also associated with poor prognosis. Previous analyses have reported that the human megakaryoblastic cells can be differentiated into cells with megakaryocyte (MK)-like characteristics by phorbol 12-myristate 13-acetate (PMA). However, little is known about the mechanism responsible for regulating this differentiation process. We performed long non-coding RNA (lncRNA) profiling to investigate the differently expressed lncRNAs in megakaryocyte blast cells treated with and without PMA and examined those that may be responsible for the PMA-induced differentiation of megakaryoblasts into MKs. We found 30 out of 90 lncRNA signatures to be differentially expressed after PMA treatment of megakaryoblast cells, including the highly expressed JPX lncRNA. Further, in silico lncRNA-miRNA and miRNA-mRNA interaction analysis revealed that the JPX is likely involved in unblocking the expression of TGF-β receptor (TGF-βR) by sponging oncogenic miRNAs (miR-9-5p, miR-17-5p, and miR-106-5p) during MK differentiation. Further, we report the activation of TGF-βR-induced non-canonical ERK1/2 and PI3K/AKT pathways during PMA-induced MK differentiation and ploidy development. The present study demonstrates that TGF-βR-induced non-canonical ERK1/2 and PI3K/AKT pathways are associated with PMA-induced MK differentiation and ploidy development; in this molecular mechanism, JPX lncRNA could act as a decoy for miR-9-5p, miR-17-5p, and miR-106-5p, titrating them away from TGF-βR mRNAs. Importantly, this study reveals the activation of ERK1/2 and PI3K/AKT pathway in PMA-induced Dami cell differentiation into MK. The identified differentially expressed lncRNA signatures may facilitate further study of the detailed molecular mechanisms associated with MK development. Thus, our data provide numerous targets with therapeutic potential for the modulation of the differentiation of megakaryoblastic cells in AMKL.

Endocannabinoid system: Role in blood cell development, neuroimmune interactions and associated disorders

The endocannabinoid system (ECS) is a complex physiological network involved in creating homeostasis and maintaining human health. Studies of the last 40 years have shown that endocannabinoids (ECs), a group of bioactive lipids, together with their set of receptors, function as one of the most important physiologic systems in human body. ECs and cannabinoid receptors (CBRs) are found throughout the body: in the brain tissues, immune cells, and in the peripheral organs and tissues as well. In recent years, ECs have emerged as key modulators of affect, neurotransmitter release, immune function, and several other physiological functions. This modulatory homoeostatic system operates in the regulation of brain activity and states of physical health and disease. In several research studies and patents the ECS has been recognised with neuro-protective properties thus it might be a target in neurodegenerative diseases. Most immune cells express these bioactive lipids and their receptors, recent data also highlight the immunomodulatory effects of endocannabinoids. Interplay of immune and nervous system has been recognized in past, recent studies suggest that ECS function as a bridge between neuronal and immune system. In several ongoing clinical trial studies, the ECS has also been placed in the anti-cancer drugs spotlight. This review summarizes the literature of cannabinoid ligands and their biosynthesis, cannabinoid receptors and their distribution, and the signaling pathways initiated by the binding of cannabinoid ligands to cannabinoid receptors. Further, this review highlights the functional role of cannabinoids and ECS in blood cell development, neuroimmune interactions and associated disorders. Moreover, we highlight the current state of knowledge of cannabinoid ligands as the mediators of neuroimmune interactions, which can be therapeutically effective for neuro-immune disorders and several diseases associated with neuroinflammation.

Co-stimulatory effect of TLR2 and TLR4 stimulation on megakaryocytic development is mediated through PI3K/NF-ĸB and XBP-1 loop

Toll-like receptors (TLRs) are a class of proteins (patterns recognition receptors-PRRs) capable of recognizing molecules frequently found in pathogens (that are so-called pathogen-associated molecular patterns-PAMPs), they play a key role in the initiation of innate immune response by detecting PAMPs. Our findings show that the functional effects of TLRs co-stimulation on megakaryocytopoiesis. A single cell may receive multiple signal inputs and we consider that multiple TLRs are likely triggered during infection by multiple PAMPs that, in turn, might be involved in infection driven megakaryocytopoiesis, and the present study provide the evidence for the megakaryocytic effects of TLRs co-stimulation.

Virodhamine, an endocannabinoid, induces megakaryocyte differentiation by regulating MAPK activity and function of mitochondria

Endocannabinoids are well-known regulators of neurotransmission by activating the cannabinoid (CB) receptors. Endocannabinoids are being used extensively for the treatment of various neurological disorders such as Alzheimer's and Parkinson's diseases. Although endocannabinoids are well studied in cell survival, proliferation, and differentiation in various neurological disorders and several cancers, the functional role in the regulation of blood cell development is less examined. In the present study, virodhamine, which is an agonist of CB receptor-2, was used to examine its effect on megakaryocytic development from a megakaryoblastic cell. We observed that virodhamine increases cell adherence, cell size, and cytoplasmic protrusions. Interestingly, we have also observed large nucleus and increased expression of megakaryocytic marker (CD61), which are the typical hallmarks of megakaryocytic differentiation. Furthermore, the increased expression of CB2 receptor was noticed in virodhamine-induced megakaryocytic cells. The effect of virodhamine on megakaryocytic differentiation could be mediated through CB2 receptor. Therefore, we have studied virodhamine induced molecular regulation of megakaryocytic differentiation; mitogen-activated protein kinase (MAPK) activity, mitochondrial function, and reactive oxygen species (ROS) production were majorly affected. The altered mitochondrial functions and ROS production is the crucial event associated with megakaryocytic differentiation and maturation. In the present study, we report that virodhamine induces megakaryocytic differentiation by triggering MAPK signaling and ROS production either through MAPK effects on ROS-generating enzymes or by the target vanilloid receptor 1-mediated regulation of mitochondrial function.

Epigenetic Mechanisms: Role in Hematopoietic Stem Cell Lineage Commitment and Differentiation

Major breakthroughs in the last several decades have contributed to our knowledge of the genetic regulation in development. Although epigenetics is not a new concept, unfortunately, the role of epigenetics has not come to fruition in the past. But the field of epigenetics has exploded within the past decade. Now, growing evidences show a complex network of epigenetic regulation in development. The epigenetic makeup of a cell, tissue or individual is much more complex than their genetic complement. Epigenetic modifications are more important for normal development by maintaining the gene expression pattern in tissue- and context-specific manner. Deregulation of epigenetic mechanism can lead to altered gene expression and its function, which result in altered tissue specific function of cells and malignant transformation. Epigenetic modifications directly shape Hematopoietic Stem Cell (HSC) developmental cascades, including their maintenance of self-renewal and multilineage potential, lineage commitment, and aging. Hence, there is a growing admiration for epigenetic players and their regulatory function in haematopoiesis. Epigenetic mechanisms underlying these modifications in mammalian genome are still not completely understood. This review mainly explains 3 key epigenetics mechanisms including DNA methylation, histone modifications and non-coding RNAs inference in hematopoietic lineage commitment and differentiation.

Endoplasmic reticulum stress induced apoptosis and caspase activation is mediated through mitochondria during megakaryocyte differentiation

Megakaryocytopoiesis involves the process of the development of hematopoietic stem cells into megakaryocytes (MKs), which are the specialized cells responsible for the production of blood platelets. Platelets are one of the crucial factors for hemostasis and thrombosis. In terminally differentiated MKs, many molecular process such as caspase activation and a massive cytoskeletal rearrangement drive the formation of cytoplasmic extensions called proplatelets. These cytoplasmic extensions packed with granules and organelles are then released from the bone marrow into the blood circulation as platelets. Classically, caspase activation is associated with apoptosis and recent reports suggest their involvement in cell differentiation and maturation. There is no clear evidence about the stimulus for caspase activation during megakaryocyte development. In the current study, we attempted to understand the importance of endoplasmic reticulum stress in the caspase activation during megakaryocyte maturation. We used human megakaryoblstic cell line (Dami cells) as an experimental model. We used PMA (Phorbol 12-myristate 13 acetate) to induce megakaryocytic differentiation to understand the involvement of ER stress and caspase activation during MK maturation. Further, we used Thapsigargin, a non-competitive inhibitor of the sarco/endoplasmic reticulum Ca²⁺ ATPase (SERCA) as a positive control to induce ER stress. We observed larger and adherent cells with the increased expression of megakaryocytic markers (CD41 and CD61) and UPR markers in PMA or Thapsigargin treated cells as compared to control. Also, Thapsigargin treatment induced increased caspase activity and PARP cleavage. The increased expression of megakaryocyte maturation markers alongside with ER stress and caspase activation suggests the importance of ER stress in caspase activation during MK maturation.

Current Updates on Role of Lipids in Hematopoiesis

Hematopoiesis is the process which generates all the mature blood cells from the rare pool of Hematopoietic stem cells (HSCs). Asymmetric cell division of HSCs provide it dual capacity for self-renewal and multi-potent differentiation. Hematopoiesis is a steady state process in which mature blood cells are produced at the same rate at which they are lost, establishing a homeostasis. HSCs are regulated through their environmental niche, cytokine signalling, and the orchestrated activities of various transcription factors. However, there is very little information available about the signal transduction events that regulate HSC function; in particular, the effects of bioactive lipids and lipid mediators are not well understood. Recent studies have added an important aspect of this process, introducing the role of lipids in cell fate decisions during hematopoiesis. The mechanisms of bioactive lipids and their derivatives have been studied extensively in signal transduction and various other cellular processes. This review focuses on various categories of lipids and their regulatory mechanisms in HSCs and their comment into different blood cells. Moreover, we also discuss the role of lipid signalling specifically in megakaryocyte and platelets.

Antifungal anthraquinones from Saprosma fragrans

A new 3,4-dihydroxy-1-methoxy anthraquinone-2-corboxaldehyde (1) together with a known anthraquinone, damnacanthal (2), were isolated from the chloroform fraction of the aerial part (whole plant without root) of Saprosma fragrans. The isolated anthraquinones (1) and (2) were found to exhibit antifungal activity against Trichophyton mentagrophytes and Sporitrichum schenckii. Their structures were established by chemical and spectral analysis.