bims-almceb Biomed News
on Acute Leukemia Metabolism and Cell Biology
Issue of 2021‒07‒18
seven papers selected by
Camila Kehl Dias
Federal University of Rio Grande do Sul

  1. Biol Chem. 2021 03 26. 402(4): 461-468
      The chemoresistance is one of the major challenges for acute myeloid leukemia (AML) treatment. We found that the expression of histone deacetylase 8 (HDAC8) was increased in daunorubicin (DNR) resistant AML cells, while targeted inhibition of HDAC8 by its specific siRNA or inhibitor can restore sensitivity of DNR treatment . Further, targeted inhibition of HDAC8 can suppress expression of interleukin 6 (IL-6) and IL-8. While recombinant IL-6 (rIL-6) and rIL-8 can reverse si-HDAC8-resored DNR sensitivity of AML cells. Mechanistical study revealed that HDAC8 increased the expression of p65, one of key components of NF-κB complex, to promote the expression of IL-6 and IL-8. It might be due to that HDAC8 can directly bind with the promoter of p65 to increase its transcription and expression. Collectively, our data suggested that HDAC8 promotes DNR resistance of human AML cells via regulation of IL-6 and IL-8.
    Keywords:  AML; HDAC8; IL-6; IL-8; p65; resistance
  2. Indian J Hematol Blood Transfus. 2021 Jul;37(3): 391-397
      The proportion of CD34 + CD38 - CD123 + leukemia stem cells (LSCs) at diagnosis of Acute Myeloid Leukemia (AML) correlated with induction remission (IR), relapse free survival and overall survival in few studies. Prospectively bone marrows of AML patients were immunophenotyped for CD34 + CD38 - CD123 + LSCs at baseline using sequential gating, relevant clinical and laboratory data collected and clinical outcomes were studied.The patients (n = 47) were risk stratified as favorable risk, intermediate risk and adverse risk. The percent of LSCs at baseline in favorable risk group (mean = 13.06%) was significantly less than the adverse (mean = 34.8%, p = 0.027) and the intermediate risk group (mean = 53.2%, p = 0.001). On further analysis, 12 patients attaining IR in intermediate risk group had significantly less LSCs than 15 in non-IR group (mean = 21.18%; range 3-85.6% vs mean = 73.85%; range 12.1-97.9%, p = 0.0002). Of all 47 patients, the proportion of LSCs at baseline was significantly less in those achieving IR (p = 0.024) and correlated with time to response (TTR) (rs = 0.432). Thus to conclude, the proportion of CD34 + CD38 - CD123 + LSCs at diagnosis is less in the favorable than the intermediate and adverse risk groups and is  an emerging novel marker for predicting remission in the prognostically diverse intermediate risk group.
    Keywords:  Aml; Induction remission; Leukemia stem cells; Prognosis; Relapse
  3. Exp Hematol Oncol. 2021 Jul 10. 10(1): 39
      Despite the advances in intensive chemotherapy regimens and targeted therapies, overall survival (OS) of acute myeloid leukemia (AML) remains unfavorable due to inevitable chemotherapy resistance and high relapse rate, which mainly caused by the persistence existence of leukemia stem cells (LSCs). Bone marrow microenvironment (BMM), the home of hematopoiesis, has been considered to play a crucial role in both hematopoiesis and leukemogenesis. When interrupted by the AML cells, a malignant BMM formed and thus provided a refuge for LSCs and protecting them from the cytotoxic effects of chemotherapy. In this review, we summarized the alterations in the bidirectional interplay between hematopoietic cells and BMM in the normal/AML hematopoietic environment, and pointed out the key role of these alterations in pathogenesis and chemotherapy resistance of AML. Finally, we focused on the current potential BMM-targeted strategies together with future prospects and challenges. Accordingly, while further research is necessary to elucidate the underlying mechanisms behind LSC-BMM interaction, targeting the interaction is perceived as a potential therapeutic strategy to eradicate LSCs and ultimately improve the outcome of AML.
    Keywords:  Acute myeloid leukemia; Bone marrow microenvironment; Environment-mediated drug resistance; Interaction; Leukemia stem cell
  4. Front Oncol. 2021 ;11 678333
      Cancer stem cells (CSCs) are a minority subset of cancer cells that can drive tumor initiation, promote tumor progression, and induce drug resistance. CSCs are difficult to eliminate by conventional therapies and eventually mediate tumor relapse and metastasis. Moreover, recent studies have shown that CSCs display plasticity that renders them to alter their phenotype and function. Consequently, the varied phenotypes result in varied tumorigenesis, dissemination, and drug-resistance potential, thereby adding to the complexity of tumor heterogeneity and further challenging clinical management of cancers. In recent years, tumor microenvironment (TME) has become a hotspot in cancer research owing to its successful application in clinical tumor immunotherapy. Notably, emerging evidence shows that the TME is involved in regulating CSC plasticity. TME can activate stemness pathways and promote immune escape through cytokines and exosomes secreted by immune cells or stromal cells, thereby inducing non-CSCs to acquire CSC properties and increasing CSC plasticity. However, the relationship between TME and plasticity of CSCs remains poorly understood. In this review, we discuss the emerging investigations on TME and CSC plasticity to illustrate the underlying mechanisms and potential implications in suppressing cancer progression and drug resistance. We consider that this review can help develop novel therapeutic strategies by taking into account the interlink between TME and CSC plasticity.
    Keywords:  cancer progression; cancer stem cell; plasticity; resistance; tumor microenvironment
  5. Cell Oncol (Dordr). 2021 Jul 09.
      BACKGROUND: The ability of cancer cells to develop treatment resistance is one of the primary factors that prevent successful treatment. Although initially thought to be dysfunctional in cancer, mitochondria are significant players that mediate treatment resistance. Literature indicates that cancer cells reutilize their mitochondria to facilitate cancer progression and treatment resistance. However, the mechanisms by which the mitochondria promote treatment resistance have not yet been fully elucidated.CONCLUSIONS AND PERSPECTIVES: Here, we describe various means by which mitochondria can promote treatment resistance. For example, mutations in tricarboxylic acid (TCA) cycle enzymes, i.e., fumarate hydratase and isocitrate dehydrogenase, result in the accumulation of the oncometabolites fumarate and 2-hydroxyglutarate, respectively. These oncometabolites may promote treatment resistance by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, inhibiting the anti-tumor immune response, or promoting angiogenesis. Furthermore, stromal cells can donate intact mitochondria to cancer cells after therapy to restore mitochondrial functionality and facilitate treatment resistance. Targeting mitochondria is, therefore, a feasible strategy that may dampen treatment resistance. Analysis of tumoral DNA may also be used to guide treatment choices. It will indicate whether enzymatic mutations are present in the TCA cycle and, if so, whether the mutations or their downstream signaling pathways can be targeted. This may improve treatment outcomes by inhibiting treatment resistance or promoting the effectiveness of anti-angiogenic agents or immunotherapy.
    Keywords:  2-Hydroxyglutarate; Fumarate; Mitochondria; Mitochondrial transfer; Treatment resistance
  6. Transl Oncol. 2021 Jul 09. pii: S1936-5233(21)00151-0. [Epub ahead of print]14(9): 101159
      The persistence of leukemia stem cells (LSCs) is one of the leading causes of chemoresistance in acute myeloid leukemia (AML). To explore the factors important in LSC-mediated resistance, we use mass spectrometry to screen the factors related to LSC chemoresistance and defined IFN-γ-inducible lysosomal thiol reductase (GILT) as a candidate. We found that the GILT expression was upregulated in chemoresistant CD34+ AML cells. Loss of function studies demonstrated that silencing of GILT in AML cells sensitized them to Ara-C treatment both in vitro and in vivo. Further mechanistic findings revealed that the ROS-mediated mitochondrial damage plays a pivotal role in inducing apoptosis of GILT-inhibited AML cells after Ara-C treatment. The inactivation of PI3K/Akt/ nuclear factor erythroid 2-related factor 2 (NRF2) pathway, causing reduced generation of antioxidants such as SOD2 and leading to a shifted ratio of GSH/GSSG to the oxidized form, contributed to the over-physiological oxidative status in the absence of GILT. The prognostic value of GILT was also validated in AML patients. Taken together, our work demonstrated that the inhibition of GILT increases AML chemo-sensitivity through elevating ROS level and induce oxidative mitochondrial damage-mediated apoptosis, and inhibition of the PI3K/Akt/NRF2 pathway enhances the intracellular oxidative state by disrupting redox homeostasis, providing a potentially effective way to overcome chemoresistance of AML.
    Keywords:  AML; Chemoresistance; GILT; LSC; Oxidative stress
  7. Drug Discov Today. 2021 Jul 12. pii: S1359-6446(21)00314-7. [Epub ahead of print]
      Cancer is a complex heterogenic disease with significant therapeutic challenges. The presence of cancer stem cells (CSCs) in cancer tissue orchestrates tumor heterogeneity, the tumor microenvironment (TME), disease relapse, and therapeutic resistance. Hence, it is imperative to explore how progenitor or cancer-initiating cells acquire stemness features and reprogram different biological mechanisms to maintain their sustained oncogenicity. Interestingly, deregulation of F-box proteins (FBPs) is crucial for cancer stemness features, including drug resistance and disease relapse. In this review, we highlight recent updates on the clinical significance of targeting FBPs in cancer therapy, with emphasis on eliminating CSCs and associated therapeutic challenges. Moreover, we also discuss novel strategies for the selective elimination of CSCs by targeting FBPs.
    Keywords:  F-box proteins and signaling; cancer pathogenesis; cancer stem cells; poor clinical outcomes; stemness