A systematic evaluation of the safety and toxicity of fingolimod for its potential use in the treatment of acute myeloid leukaemia

Identifying key genes and functionally enriched pathways in acute myeloid leukemia by weighted gene co-expression network analysis

Acute myeloid leukemia (AML) is characterized by the uncontrolled proliferation of myeloid leukemia cells in the bone marrow and other hematopoietic tissues and is highly heterogeneous. While with the progress of sequencing technology, understanding of the AML-related biomarkers is still incomplete. The purpose of this study is to identify potential biomarkers for prognosis of AML. Based on WGCNA analysis of gene mutation expression, methylation level distribution, mRNA expression, and AML-related genes in public databases were employed for investigating potential biomarkers for the prognosis of AML. This study screened a total of 6153 genes by analyzing various changes in 103 acute myeloid leukemia (AML) samples, including gene mutation expression, methylation level distribution, mRNA expression, and AML-related genes in public databases. Moreover, seven AML-related co-expression modules were mined by WGCNA analysis, and twelve biomarkers associated with the AML prognosis were identified from each top 10 genes of the seven co-expression modules. The AML samples were then classified into two subgroups, the prognosis of which is significantly different, based on the expression of these twelve genes. The differentially expressed 7 genes of two subgroups (HOXB-AS3, HOXB3, SLC9C2, CPNE8, MEG8, S1PR5, MIR196B) are mainly involved in glucose metabolism, glutathione biosynthesis, small G protein-mediated signal transduction, and the Rap1 signaling pathway. With the utilization of WGCNA mining, seven gene co-expression modules were identified from the TCGA database, and there are unreported genes that may be potential driver genes of AML and may be the direction to identify the possible molecular signatures to predict survival of AML patients and help guide experiments for potential clinical drug targets.

Therapeutic implications for sphingolipid metabolism in metabolic dysfunction-associated steatohepatitis

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD), a leading cause of chronic liver disease, has increased worldwide along with the epidemics of obesity and related dysmetabolic conditions characterized by impaired glucose metabolism and insulin signaling, such as type 2 diabetes mellitus (T2D). MASLD can be defined as an excessive accumulation of lipid droplets in hepatocytes that occurs when the hepatic lipid metabolism is totally surpassed. This metabolic lipid inflexibility constitutes a central node in the pathogenesis of MASLD and is frequently linked to the overproduction of lipotoxic species, increased cellular stress, and mitochondrial dysfunction. A compelling body of evidence suggests that the accumulation of lipid species derived from sphingolipid metabolism, such as ceramides, contributes significantly to the structural and functional tissue damage observed in more severe grades of MASLD by triggering inflammatory and fibrogenic mechanisms. In this context, MASLD can further progress to metabolic dysfunction-associated steatohepatitis (MASH), which represents the advanced form of MASLD, and hepatic fibrosis. In this review, we discuss the role of sphingolipid species as drivers of MASH and the mechanisms involved in the disease. In addition, given the absence of approved therapies and the limited options for treating MASH, we discuss the feasibility of therapeutic strategies to protect against MASH and other severe manifestations by modulating sphingolipid metabolism.

Promising Molecular Targets in Pharmacological Therapy for Neuronal Damage in Brain Injury

The complex etiopathogenesis of brain injury associated with neurodegeneration has sparked a lot of studies in the last century. These clinical situations are incurable, and the currently available therapies merely act on symptoms or slow down the course of the diseases. Effective methods are being sought with an intent to modify the disease, directly acting on the properly studied targets, as well as to contribute to the development of effective therapeutic strategies, opening the possibility of refocusing on drug development for disease management. In this sense, this review discusses the available evidence for mitochondrial dysfunction induced by Ca2+ miscommunication in neurons, as well as how targeting phosphorylation events may be used to modulate protein phosphatase 2A (PP2A) activity in the treatment of neuronal damage. Ca2+ tends to be the catalyst for mitochondrial dysfunction, contributing to the synaptic deficiency seen in brain injury. Additionally, emerging data have shown that PP2A-activating drugs (PADs) suppress inflammatory responses by inhibiting different signaling pathways, indicating that PADs may be beneficial for the management of neuronal damage. In addition, a few bioactive compounds have also triggered the activation of PP2A-targeted drugs for this treatment, and clinical studies will help in the authentication of these compounds. If the safety profiles of PADs are proven to be satisfactory, there is a case to be made for starting clinical studies in the setting of neurological diseases as quickly as possible.

A statistical network pre-processing method to improve relevance and significance of gene lists in microarray gene expression studies

BACKGROUND

Microarrays can perform large scale studies of differential expressed gene (DEGs) and even single nucleotide polymorphisms (SNPs), thereby screening thousands of genes for single experiment simultaneously. However, DEGs and SNPs are still just as enigmatic as the first sequence of the genome. Because they are independent from the affected biological context. Pathway enrichment analysis (PEA) can overcome this obstacle by linking both DEGs and SNPs to the affected biological pathways and consequently to the underlying biological functions and processes.

RESULTS

To improve the enrichment analysis results, we present a new statistical network pre-processing method by mapping DEGs and SNPs on a biological network that can improve the relevance and significance of the DEGs or SNPs of interest to incorporate pathway topology information into the PEA. The proposed methodology improves the statistical significance of the PEA analysis in terms of computed p value for each enriched pathways and limit the number of enriched pathways. This helps reduce the number of relevant biological pathways with respect to a non-specific list of genes.

CONCLUSION

The proposed method provides two-fold enhancements. Network analysis reveals fewer DEGs, by selecting only relevant DEGs and the detected DEGs improve the enriched pathways' statistical significance, rather than simply using a general list of genes.

PP2A-activating Drugs Enhance FLT3 Inhibitor Efficacy through AKT Inhibition-Dependent GSK-3β-Mediated c-Myc and Pim-1 Proteasomal Degradation

Fms-like tyrosine-like kinase 3 internal tandem duplication (FLT3-ITD) is present in acute myeloid leukemia (AML) in 30% of patients and is associated with short disease-free survival. FLT3 inhibitor efficacy is limited and transient but may be enhanced by multitargeting of FLT3-ITD signaling pathways. FLT3-ITD drives both STAT5-dependent transcription of oncogenic Pim-1 kinase and inactivation of the tumor-suppressor protein phosphatase 2A (PP2A), and FLT3-ITD, Pim-1, and PP2A all regulate the c-Myc oncogene. We studied mechanisms of action of cotreatment of FLT3-ITD-expressing cells with FLT3 inhibitors and PP2A-activating drugs (PADs), which are in development. PADs, including FTY720 and DT-061, enhanced FLT3 inhibitor growth suppression and apoptosis induction in FLT3-ITD-expressing cell lines and primary AML cells in vitro and MV4-11 growth suppression in vivo PAD and FLT3 inhibitor cotreatment independently downregulated c-Myc and Pim-1 protein through enhanced proteasomal degradation. c-Myc and Pim-1 downregulation was preceded by AKT inactivation, did not occur in cells expressing myristoylated (constitutively active) AKT1, and could be induced by AKT inhibition. AKT inactivation resulted in activation of GSK-3β, and GSK-3β inhibition blocked downregulation of both c-Myc and Pim-1 by PAD and FLT3 inhibitor cotreatment. GSK-3β activation increased c-Myc proteasomal degradation through c-Myc phosphorylation on T58; infection with c-Myc with T58A substitution, preventing phosphorylation, blocked downregulation of c-Myc by PAD and FLT3 inhibitor cotreatment. GSK-3β also phosphorylated Pim-1L/Pim-1S on S95/S4. Thus, PADs enhance efficacy of FLT3 inhibitors in FLT3-ITD-expressing cells through a novel mechanism involving AKT inhibition-dependent GSK-3β-mediated increased c-Myc and Pim-1 proteasomal degradation.

A genome-scale CRISPR Cas9 dropout screen identifies synthetically lethal targets in SRC-3 inhibited cancer cells

Steroid receptor coactivator 3 (SRC-3/NCoA3/AIB1), is a key regulator of gene transcription and it plays a central role in breast cancer (BC) tumorigenesis, making it a potential therapeutic target. Beyond its function as an important regulator of estrogen receptor transcriptional activity, SRC-3 also functions as a coactivator for a wide range of other transcription factors, suggesting SRC-3 inhibition can be beneficial in hormone-independent cancers as well. The recent discovery of a potent SRC-3 small molecule inhibitor, SI-2, enabled the further development of additional related compounds. SI-12 is an improved version of SI-2 that like SI-2 has anti-proliferative activity in various cancer types, including BC. Here, we sought to identify gene targets, that when inhibited in the presence of SI-12, would lead to enhanced BC cell cytotoxicity. We performed a genome-scale CRISPR-Cas9 screen in MCF-7 BC cells under conditions of pharmacological pressure with SI-12. A parallel screen was performed with an ER inhibitor, fulvestrant, to shed light on both common and distinct activities between SRC-3 and ERα inhibition. Bearing in mind the key role of SRC-3 in tumorigenesis of other types of cancer, we extended our study by validating potential hits identified from the MCF-7 screen in other cancer cell lines.

Understanding Breast cancer: from conventional therapies to repurposed drugs

Breast cancer is the most common cancer among women and is considered a developed country disease. Moreover, is a heterogenous disease, existing different types and stages of breast cancer development, therefore, better understanding of cancer biology, helps to improve the development of therapies. The conventional treatments accessible after diagnosis, have the main goal of controlling the disease, by improving survival. In more advance stages the aim is to prolong life and symptom palliation care. Surgery, radiation therapy and chemotherapy are the main options available, which must be adapted to each person individually. However, patients are developing resistance to the conventional therapies. This resistance is due to alterations in important regulatory pathways such as PI3K/AKt/mTOR, this pathway contributes to trastuzumab resistance, a reference drug to treat breast cancer. Therefore, is proposed the repurposing of drugs, instead of developing drugs de novo, for example, to seek new medical treatments within the drugs available, to be used in breast cancer treatment. Providing safe and tolerable treatments to patients, and new insights to efficacy and efficiency of breast cancer treatments. The economic and social burden of cancer is enormous so it must be taken measures to relieve this burden and to ensure continued access to therapies to all patients. In this review we focus on how conventional therapies against breast cancer are leading to resistance, by reviewing those mechanisms and discussing the efficacy of repurposed drugs to fight breast cancer.

Targeting Approaches of Nanomedicines in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a hematological malignancy, which is commonly associated with high incidence and mortality among adult patients. The standard induction regimen for AML has been substantially unchanged over the past 40 years, for which novel nanomedicines have represented a promising strategy in AML therapies. Despite developments of multiple nanoparticles formulated with drugs or genes, less there is not much information available about approaches in AML is available. This review presents an overview of nanomedicines currently being evaluated in AML. First, it briefly summarized conventional chemotherapies in use. Second, nanomedicines presently ongoing in clinical trials or preclinical researches were classified and described, with illustrative examples from recent literatures. Finally, limitations and potential safety issues concerns in clinical translation of AML treatment were discussed as well.

FTY720 induces non-canonical phosphatidylserine externalization and cell death in acute myeloid leukemia

FTY720 (fingolimod) is a FDA-approved sphingosine analog that is phosphorylated in vivo to modulate sphingosine-1-phosphate receptor (S1PR) signaling for immunosuppression in patients with refractory multiple sclerosis. FTY720 also exhibits promising anticancer efficacy in several preclinical models. While FTY720-induced cytotoxicity is not due to S1PR signaling, the mechanism remains unclear and is reported to occur through various cell death pathways. Here, we performed a systematic, mechanistic study of FTY720-induced cell death in acute myeloid leukemia (AML). We found that FTY720 induced cell death in a panel of genetically diverse AML cell lines that was accompanied by rapid phosphatidylserine (PS) externalization. Importantly, FTY720-induced PS exposure was not due to any direct effects on plasma membrane integrity and was independent of canonical signaling by regulated cell death pathways known to activate lipid flip-flop, including caspase-dependent apoptosis/pyroptosis, necroptosis, ferroptosis, and reactive oxygen species-mediated cell death. Notably, PS exposure required cellular vacuolization induced by defects in endocytic trafficking and was suppressed by the inhibition of PP2A and shedding of Annexin V-positive subcellular particles. Collectively, our studies reveal a non-canonical pathway underlying PS externalization and cell death in AML to provide mechanistic insight into the antitumor properties of FTY720.

Protein phosphatase 2A as a therapeutic target in inflammation and neurodegeneration

Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric enzyme that catalyzes the selective removal of phosphate groups from protein serine and threonine residues. Emerging evidence suggests that it functions as a tumor suppressor by constraining phosphorylation-dependent signalling pathways that regulate cellular transformation and metastasis. Therefore, PP2A-activating drugs (PADs) are being actively sought and investigated as potential novel anti-cancer treatments. Here we explore the concept that PP2A also constrains inflammatory responses through its inhibitory effects on various signalling pathways, suggesting that PADs may be effective in the treatment of inflammation-mediated pathologies.

Activation of protein phosphatase 2A in FLT3+ acute myeloid leukemia cells enhances the cytotoxicity of FLT3 tyrosine kinase inhibitors

Constitutive activation of the receptor tyrosine kinase Fms-like tyrosine kinase 3 (FLT3), via co-expression of its ligand or by genetic mutation, is common in acute myeloid leukemia (AML). In this study we show that FLT3 activation inhibits the activity of the tumor suppressor, protein phosphatase 2A (PP2A). Using BaF3 cells transduced with wildtype or mutant FLT3, we show that FLT3-induced PP2A inhibition sensitizes cells to the pharmacological PP2A activators, FTY720 and AAL(S). FTY720 and AAL(S) induced cell death and inhibited colony formation of FLT3 activated cells. Furthermore, PP2A activators reduced the phosphorylation of ERK and AKT, downstream targets shared by both FLT3 and PP2A, in FLT3/ITD⁺ BaF3 and MV4-11 cell lines. PP2A activity was lower in primary human bone marrow derived AML blasts compared to normal bone marrow, with blasts from FLT3-ITD patients displaying lower PP2A activity than WT-FLT3 blasts. Reduced PP2A activity was associated with hyperphosphorylation of the PP2A catalytic subunit, and reduced expression of PP2A structural and regulatory subunits. AML patient blasts were also sensitive to cell death induced by FTY720 and AAL(S), but these compounds had minimal effect on normal CD34+ bone marrow derived monocytes. Finally, PP2A activating compounds displayed synergistic effects when used in combination with tyrosine kinase inhibitors in FLT3-ITD⁺ cells. A combination of Sorafenib and FTY720 was also synergistic in the presence of a protective stromal microenvironment. Thus combining a PP2A activating compound and a FLT3 inhibitor may be a novel therapeutic approach for treating AML.

Shuyu capsules relieve liver-qi depression by regulating ERK-CREB-BDNF signal pathway in central nervous system of rat

The purpose of this study was to investigate the possible therapeutic mechanism of Shuyu capsules in liver-qi depression. Liver-qi depression rats were prepared based on chronic unpredictable mild stress (CUMS) and delayed constraint. Rats were gavaged with Shuyu capsule, fluoxetine, Radix Bupleuri and Radix Paeoniae Alba to constrct rat models. Body weight test, sucrose preference test and open-field test were applied to test rat models. Western blot analysis and quantitative real-time PCR was applied to determine the relative expression of extracellular signal-regulated protein kinase (ERK), cyclic AMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in hippocampus and frontal lobe tissues. ELISA was used to detect the content of BDNF in serum. Body weight, sugar intake and total distance were significantly decreased in depression group compared with control. The four drugs significantly increased levels of these factors. Compared with control group, ERK, CREB and BDNF expression were significantly decreased in depression group in both hippocampus and frontal lobe tissues at both mRNA and protein level. Shuyu capsule and fluoxetine group showed a significant increase in the expression of ERK, CREB and BDNF at mRNA, p-ERK and p-BDNF at protein level. Compared with Radix Paeoniae Alba, Radix Bupleuri were better in the rescue of ERK, CREB and BDNF expression. In conclusion, the pathogenesis of liver-qi depression associated with lower expression of ERK, CREB and BDNF in hippocampus and frontal. Shuyu capsule and main constitution alleviated the depressive-like behaviors and reversed the disruptions of the p-ERK, p-CREB and BDNF in stressed rats.

FTY720 inhibits mesothelioma growth in vitro and in a syngeneic mouse model

BACKGROUND

Malignant mesothelioma (MM) is a very aggressive type of cancer, with a dismal prognosis and inherent resistance to chemotherapeutics. Development and evaluation of new therapeutic approaches is highly needed. Immunosuppressant FTY720, approved for multiple sclerosis treatment, has recently raised attention for its anti-tumor activity in a variety of cancers. However, its therapeutic potential in MM has not been evaluated yet.

METHODS

Cell viability and anchorage-independent growth were evaluated in a panel of MM cell lines and human mesothelial cells (HM) upon FTY720 treatment to assess in vitro anti-tumor efficacy. The mechanism of action of FTY720 in MM was assessed by measuring the activity of phosphatase protein 2A (PP2A)-a major target of FTY720. The binding of the endogenous inhibitor SET to PP2A in presence of FTY720 was evaluated by immunoblotting and immunoprecipitation. Signaling and activation of programmed cell death were evaluated by immunoblotting and flow cytometry. A syngeneic mouse model was used to evaluate anti-tumor efficacy and toxicity profile of FTY720 in vivo.

RESULTS

We show that FTY720 significantly suppressed MM cell viability and anchorage-independent growth without affecting normal HM cells. FTY720 inhibited the phosphatase activity of PP2A by displacement of SET protein, which appeared overexpressed in MM, as compared to HM cells. FTY720 promoted AKT dephosphorylation and Bcl-2 degradation, leading to induction of programmed cell death, as demonstrated by caspase-3 and PARP activation, as well as by cytochrome c and AIF intracellular translocation. Moreover, FTY720 administration in vivo effectively reduced tumor burden in mice without apparent toxicity.

CONCLUSIONS

Our preclinical data indicate that FTY720 is a potentially promising therapeutic agent for MM treatment.