Venetoclax-Resistant MV4-11 Leukemic Cells Activate PI3K/AKT Pathway for Metabolic Reprogramming and Redox Adaptation for Survival

Lysine-Rich Polypeptide Modulates Forkhead Box O3 and Phosphoinositide 3-Kinase-Protein Kinase B Pathway To Induce Apoptosis in Breast Cancer

The PI3K/AKT/FOXO3 pathway is one of the most frequently involved signaling pathways in cancer, including breast cancer. Therefore, we synthesized a novel lysine-rich polypeptide (Lys-PP) using de novo assembly method and evaluated its anticancer effect. We characterized the structural and physicochemical properties of Lys-PP using various techniques. Later, we used integrated approaches such as in silico, in vitro, and in vivo analysis to confirm the anticancer and therapeutic effect of Lys-PP. First, RNA sequencing suggests Lys-PP disrupted the central carbon metabolic pathway through the modulation of prolactin signaling. Additionally, docking analysis also confirmed the significant association of PI3K/AKT and FOXO3 pathway to induce an apoptotic effect on cancer. Second, Lys-PP exhibited a significant cytotoxicity effect against MDA-MB-231 but no cytotoxic effects on RAW 264.7 and HEK-293, respectively. The cytotoxic effect of Lys-PP-induced apoptosis by an increase in FOXO3a protein expression and a decrease in PI3K/AKT pathway was confirmed by quantitative real-time polymerase chain reaction, immunoblotting, and fluorescent microscopy. Later, immunohistochemistry and hematoxylin and eosin staining on MDA-MD-231 showed increased FOXO3a expression and cell death in the xenograft mice model. Further, liver function, metabolic health, or lipid profile upon Lys-PP showed the absence of significant modulation in the biomarkers except for kidney-related biomarkers. Overall, our comprehensive study provides the first evidence of Lys-PP antibreast cancer action, which could serve as a potential treatment in an alternative or complementary medicine practice.

Disarib, a Specific BCL2 Inhibitor, Induces Apoptosis in Triple-Negative Breast Cancer Cells and Impedes Tumour Progression in Xenografts by Altering Mitochondria-Associated Processes

Targeted cancer therapy aims to disrupt the functions of proteins that regulate cancer progression, mainly by using small molecule inhibitors (SMIs). SMIs exert their effect by modulating signalling pathways, organelle integrity, chromatin components, and several biosynthetic processes essential for cell division and survival. Antiapoptotic protein BCL2 is highly upregulated in many cancers compared with normal cells, making it an ideal target for cancer therapy. Around 75% of primary breast cancers overexpress BCL2, providing an opportunity to explore BCL2 inhibitors as a therapeutic option. Disarib is an SMI that has been developed as a selective BCL2 inhibitor. Disarib works by disrupting BCL2-BAK interaction and activating intrinsic apoptotic pathways in leukemic cells while sparing normal cells. We investigated the effects of Disarib, a BCL2 specific inhibitor, on breast cancer cells and xenografts. Cytotoxicity and fluorometric assays revealed that Disarib induced cell death by increasing reactive oxygen species and activating intrinsic apoptotic pathways in Triple-Negative Breast Cancer cells (MDA-MB-231 and MDA-MB-468). Disarib also affected the colony-forming properties of these cells. MDA-MB-231- and MDA-MB-468-derived xenografts showed a significant reduction in tumours upon Disarib treatment. Through the transcriptomics approach, we also explored the influence of BCL2 inhibitors on energy metabolism, mitochondrial dynamics, and epithelial-to-mesenchymal transition (EMT). Mitochondrial dynamics and glucose metabolism mainly regulate energy metabolism. The change in energetics regulates tumour growth through epithelial-mesenchymal transition, and angiogenesis. RNA sequencing (RNAseq) analysis revealed that BCL2 inhibitors ABT-199 and Disarib maintain Oxphos levels in MDA-MB-231. However, key glycolytic genes were significantly downregulated. Mitochondrial fission genes were seen to be downregulated both in RNAseq data and semi quantitative real time polymerase chain reaction (qRTPCR) in Disarib-treated TNBC cells and xenografts. Lastly, Disarib inhibited wound healing and epithelial-to-mesenchymal transition. This study showed that Disarib disrupts mitochondrial function, activates the intrinsic apoptotic pathway in breast cancer, and inhibits epithelial-to-mesenchymal transition both in vitro and in vivo. These findings highlight Disarib's potential as a multifaceted therapeutic strategy for patients with Triple-Negative Breast Cancer.

Venetoclax resistance in acute myeloid leukaemia-Clinical and biological insights

Venetoclax, an oral BCL-2 inhibitor, has been widely incorporated in the treatment of acute myeloid leukaemia. The combination of hypomethylating agents and venetoclax is the current standard of care for elderly and patient's ineligible for aggressive therapies. However, venetoclax is being increasingly used with aggressive chemotherapy regimens both in the front line and in the relapse setting. Our growing experience and intensive research demonstrate that certain genetic abnormalities are associated with venetoclax sensitivity, while others with resistance, and that resistance can emerge during treatment leading to disease relapse. In the current review, we provide a summary of the known mechanisms of venetoclax cytotoxicity, both regarding the inhibition of BCL-2-mediated apoptosis and its effect on cell metabolism. We describe how these pathways are linked to venetoclax resistance and are associated with specific mutations. Finally, we provide the rationale for novel drug combinations in current and future clinical trials.

Deciphering aging-associated molecular mechanisms in bone marrow derived hematopoietic stem cells in the elderly using NGS data

Aging is a complex process that is not yet fully understood. Despite advancements in research, a deeper understanding of the underlying biological mechanisms is necessary to develop interventions that promote healthy longevity. The aim of this study was to elucidate the complex mechanisms associated with healthy aging and longevity in healthy elderly individuals. The RNA sequencing (RNA-seq) data used in this study was obtained from the Gene Expression Omnibus (GEO) database (accession number GSE104406), which was collected from Fluorescent Activated Cell Sorting (FACS) of human bone marrow derived human hematopoietic stem cells (BM-HSCs) (Lineage-, CD34+, CD38-) young (18-30 years old) and aged (65-75 years old) donors who had no known hematological malignancy, with 10 biological replicates per group. The GEO RNA-seq Experiments Interactive Navigator (GREIN) software was used to obtain raw gene-level counts and filtered metadata for this dataset. Next generation knowledge discovery (NGKD) tools provided by BioJupies were used to obtain differentially regulated pathways, gene ontologies (GO), and gene signatures in the BM-HSCs. Finally, the L1000 Characteristic Direction Signature Search Engine (L1000CDS2) tool was used to identify specific drugs that reverse aging-associated gene signatures in old but healthy individuals. The down-regulation of signaling pathways such as longevity regulation, proteasome, Notch, apoptosis, nuclear factor kappa B (NFkB), and peroxisome proliferator-activated receptors (PPAR) signaling pathways in the BM-HSCs of healthy elderly. GO functions related to negative regulation of bone morphogenetic protein (BMP), telomeric DNA binding, nucleoside binding, calcium -dependent protein binding, chromatin-DNA binding, SMAD binding, and demethylase activity were significantly downregulated in the BM-HSCs of the elderly compared to the healthy young group. Importantly, potential drugs such as salermide, celestrol, cercosporin, dorsomorphin dihydrochloride, and LDN-193189 monohydrochloride that can reverse the aging-associated signatures in HSCs from healthy elderly were identified. The analysis of RNA-seq data based on NGKD techniques revealed a plethora of differentially regulated pathways, gene ontologies, and drugs with anti-aging potential to promote healthspan in the elderly.

SOHO State of the Art Updates and Next Questions: Understanding and Overcoming Venetoclax Resistance in Hematologic Malignancies

The discovery of Venetoclax (VEN) has transformed the therapeutic landscape of acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). However, the response is heterogeneous with 10% to 50% of newly diagnosed AML patients not responding to hypomethylating agent (HMA) and VEN. Furthermore, up to 40% of responding patients relapse shortly. This review discusses the mechanism of action of Venetoclax and the major mechanisms of inherent and acquired resistance to VEN. VEN is highly specific to BCL-2 binding, as such other antiapoptotic proteins in BCL-2 family induce resistance. These antiapoptotic proteins can also be upregulated via a number of compensatory cell signaling pathways including PI3K/AKT/mTOR, the MAPK/ERK pathway, and mutant FLT3-ITD. Mutations can occur in BCL-2 and BAX proteins, or they can be silenced by TP53 mutations and other epigenetic changes. Changes to mitochondrial structure and metabolism can induce resistance. Key metabolic regulators include OXPHOS and alternative amino acid metabolism. Finally microenvironmental factors can influence VEN responses. This paper evaluates subsets of AML by differentiation, histology, cytogenetics and molecular markers and their different responses to VEN; with spliceosome mutations, ASXL1, NPM1 and IDH1/2 being favorable while others such as FLT3, TP53 and BCL-2 mutations being less responsive. Currently intensive multiagent chemotherapy and Venetoclax combinations such as 7+3+VEN are favored in fit younger AML patients. However, with resistant patients' subsets targeted combination therapies are becoming an increasingly attractive option. We explore the incorporation of non-BCL-2 inhibitors, next-generation BCL-2 and multi-protein agents, other inhibitors most prominently FLT-3 inhibitors in addition to Venetoclax, and other novel approaches for resolving Venetoclax resistance.

Extracellular matrix detached cancer cells resist oxidative stress by increasing histone demethylase KDM6 activity

Epithelial cancer cells rely on the extracellular matrix (ECM) attachment in order to spread to other organs. Detachment from the ECM is necessary for these cells to seed in other locations. When the attachment to the ECM is lost, cellular metabolism undergoes a significant shift from oxidative metabolism to glycolysis. Additionally, the cancer cells become more dependent on glutaminolysis to avoid a specific type of cell death known as anoikis, which is associated with ECM detachment. In our recent study, we observed increased expression of H3K27me3 demethylases, specifically KDM6A/B, in cancer cells that were resistant to anoikis. Since KDM6A/B is known to regulate cellular metabolism, we investigated the effects of suppressing KDM6A/B with GSK-J4 on the metabolic processes in these anoikis-resistant cancer cells. Our results from untargeted metabolomics revealed a profound impact of KDM6A/B inhibition on various metabolic pathways, including glycolysis, methyl histidine, spermine, and glutamate metabolism. Inhibition of KDM6A/B led to elevated reactive oxygen species (ROS) levels and depolarization of mitochondria, while reducing the levels of glutathione, an important antioxidant, by diminishing the intermediates of the glutamate pathway. Glutamate is crucial for maintaining a pool of reduced glutathione. Furthermore, we discovered that KDM6A/B regulates the key glycolytic genes expression like hexokinase, lactate dehydrogenase, and GLUT-1, which are essential for sustaining glycolysis in anoikis-resistant cancer cells. Overall, our findings demonstrated the critical role of KDM6A/B in maintaining glycolysis, glutamate metabolism, and glutathione levels. Inhibition of KDM6A/B disrupts these metabolic processes, leading to increased ROS levels and triggering cell death in anoikis-resistant cancer cells.

Melatonin Can Enhance the Effect of Drugs Used in the Treatment of Leukemia

Melatonin (N-acetyl-5-methoxytryptamine, MEL), secreted by the pineal gland, plays an important role in regulation of various functions in the human body. There is evidence that MEL exhibits antitumor effect in various types of cancer. We studied the combined effect of MEL and drugs from different pharmacological groups, such as cytarabine (CYT) and navitoclax (ABT-737), on the state of the pool of acute myeloid leukemia (AML) tumor cell using the MV4-11 cell line as model. The combined action of MEL with CYT or ABT-737 contributed to the decrease in proliferative activity of leukemic cells, decrease in the membrane potential of mitochondria, and increase in the production of reactive oxygen species (ROS) and cytosolic Ca2+. We have shown that introduction of MEL together with CYT or ABT-737 increases expression of the C/EBP homologous protein (CHOP) and the autophagy marker LC3A/B and decreases expression of the protein disulfide isomerase (PDI) and binding immunoglobulin protein (BIP), and, therefore, could modulate endoplasmic reticulum (ER) stress and initiate autophagy. The findings support an early suggestion that MEL is able to provide benefits for cancer treatment and be considered as an adjunct to the drugs used in cancer therapy.

Micro-Slab Coil Design for Hyperpolarized Metabolic Flux Analysis in Multiple Samples

Abnormal metabolism is a hallmark of cancer cells. Accumulating evidence suggests that metabolic changes are likely to occur before other cellular responses in cancer cells upon drug treatment. Therefore, the metabolic activity or flux in cancer cells could be a potent biomarker for cancer detection and treatment monitoring. Magnetic resonance (MR)-based sensing technologies have been developed with hyperpolarized molecules for real-time flux analysis, but they still suffer from low sensitivity and throughput. To address this limitation, we have developed an innovative miniaturized MR coil, termed micro-slab MR coil, for simultaneous analysis of metabolic flux in multiple samples. Combining this approach with hyperpolarized probes, we were able to quantify the pyruvate-to-lactate flux in two different leukemic cell lines in a non-destructive manner, simultaneously. Further, we were able to rapidly assess flux changes with drug treatment in a single hyperpolarization experiment. This new multi-sample system has the potential to transform our ability to assess metabolic dynamics at scale.

Integrated Transcriptome and Metabolomic Analysis Reveal Anti-Angiogenic Properties of Disarib, a Novel Bcl2-Specific Inhibitor

Transcriptomic profiling of several drugs in cancer cell lines has been utilised to obtain drug-specific signatures and guided combination therapy to combat drug resistance and toxicity. Global metabolomics reflects changes due to altered activity of enzymes, environmental factors, etc. Integrating transcriptomics and metabolomics can provide genotype-phenotype correlation, providing meaningful insights into alterations in gene expression and its outcome to understand differential metabolism and guide therapy. This study uses a multi-omics approach to understand the global gene expression and metabolite changes induced by Disarib, a novel Bcl2-specific inhibitor in the Ehrlich adenocarcinoma (EAC) breast cancer mouse model. RNAseq analysis was performed on EAC mouse tumours treated with Disarib and compared to the controls. The expression of 6 oncogenes and 101 tumour suppressor genes interacting with Bcl2 and Bak were modulated upon Disarib treatment. Cancer hallmark pathways like DNA repair, Cell cycle, angiogenesis, and mitochondrial metabolism were downregulated, and programmed cell death platelet-related pathways were upregulated. Global metabolomic profiling using LC-MS revealed that Oncometabolites like carnitine, oleic acid, glycine, and arginine were elevated in tumour mice compared to normal and were downregulated upon Disarib treatment. Integrated transcriptomic and metabolomic profiles identified arginine metabolism, histidine, and purine metabolism to be altered upon Disarib treatment. Pro-angiogenic metabolites, arginine, palmitic acid, oleic acid, and myristoleic acid were downregulated in Disarib-treated mice. We further validated the effect of Disarib on angiogenesis by qRT-PCR analysis of genes in the VEGF pathway. Disarib treatment led to the downregulation of pro-angiogenic markers. Furthermore, the chorioallantoic membrane assay displayed a reduction in the formation of the number of secondary blood vessels upon Disarib treatment. Disarib reduces tumours by reducing oncometabolite and activating apoptosis and downregulating angiogenesis.

Profiling the Effect of Targeting Wild Isocitrate Dehydrogenase 1 (IDH1) on the Cellular Metabolome of Leukemic Cells

Leukemia is one of the most common primary malignancies of the hematologic system in both children and adults and remains a largely incurable or relapsing disease. The elucidation of disease subtypes based on mutational profiling has not improved clinical outcomes. IDH1/2 are critical enzymes of the TCA cycle that produces α-ketoglutarate (αKG). However, their mutated version is well reported in various cancer types, including leukemia, which produces D-2 hydroxyglutarate (D-2HG), an oncometabolite. Recently, some studies have shown that wild-type IDH1 is highly expressed in non-small cell lung carcinoma (NSCLC), primary glioblastomas (GBM), and several hematological malignancies and is correlated with disease progression. This work shows that the treatment of wild-type IDH1 leukemia cells with a specific IDH1 inhibitor shifted leukemic cells toward glycolysis from the oxidative phosphorylation (OXPHOS) phenotype. We also noticed a reduction in αKG in treated cells, possibly suggesting the inhibition of IDH1 enzymatic activity. Furthermore, we found that IDH1 inhibition reduced the metabolites related to one-carbon metabolism, which is essential for maintaining global methylation in leukemic cells. Finally, we observed that metabolic alteration in IDH1 inhibitor-treated leukemic cells promoted reactive oxygen species (ROS) formation and the loss of mitochondrial membrane potential, leading to apoptosis in leukemic cells. We showed that targeting wild-type IDH1 leukemic cells promotes metabolic alterations that can be exploited for combination therapies for a better outcome.

Progress in understanding the mechanisms of resistance to BCL-2 inhibitors

Venetoclax is a new type of BH3 mimetic compound that can target the binding site in the BCL-2 protein and induce apoptosis in cancer cells by stimulating the mitochondrial apoptotic pathway. Venetoclax is especially used to treat haematological malignancies. However, with the recent expansion in the applications of venetoclax, some cases of venetoclax resistance have appeared, posing a major problem in clinical treatment. In this article, we explored several common mechanisms of venetoclax resistance. Increased expression of the antiapoptotic proteins MCL-1 and BCL-XL plays a key role in conferring cellular resistance to venetoclax. These proteins can bind to the released BIM in the context of venetoclax binding to BCL-2 and thus continue to inhibit mitochondrial apoptosis. Structural mutations in BCL-2 family proteins caused by genetic instability lead to decreased affinity for venetoclax and inhibit the intrinsic apoptosis pathway. Mutation or deletion of the BAX gene renders the BAX protein unable to anchor to the outer mitochondrial membrane to form pores. In addition to changes in BCL-2 family genes, mutations in other oncogenes can also confer resistance to apoptosis induced by venetoclax. TP53 mutations and the expansion of FLT3-ITD promote the expression of antiapoptotic proteins MCL-1 and BCL-XL through multiple signalling pathways, and interfere with venetoclax-mediated apoptosis processes depending on their affinity for BH3-only proteins. Finally, the level of mitochondrial oxidative phosphorylation in venetoclax-resistant leukaemia stem cells is highly abnormal. Not only the metabolic pathways but also the levels of important metabolic components are changed, and all of these alterations antagonize the venetoclax-mediated inhibition of energy metabolism and promote the survival and proliferation of leukaemia stem cells. In addition, venetoclax can change mitochondrial morphology independent of the BCL-2 protein family, leading to mitochondrial dysfunction. However, mitochondria resistant to venetoclax antagonize this effect, forming tighter mitochondrial cristae, which provide more energy for cell survival.