acriflavine and Leukemia--Myelogenous--Chronic--BCR-ABL-Positive

Drug repurposing has lately received increasing interest in several diseases especially in cancers, due to its advantages in facilitating the development of new therapeutic strategies, by adopting a cost-friendly approach and avoiding the strict Food and Drug Administration (FDA) regulations. Acriflavine (ACF) is an FDA approved molecule that has been extensively studied since 1912 with antiseptic, trypanocidal, anti-viral, anti-bacterial and anti-cancer effects. ACF has been shown to block the growth of solid and hematopoietic tumor cells. Indeed, ACF acts as an inhibitor of various proteins, including DNA-dependent protein kinases C (DNA-PKcs), topoisomerase I and II, hypoxia-inducible factor 1α (HIF-1α), in addition to its recent discovery as an inhibitor of the signal transducer and activator of transcription (STAT). Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder characterized by the expression of the constitutively active tyrosine kinase BCR-ABL. This protein allows the activation of several signaling pathways known for their role in cell proliferation and survival, such as the JAK/STAT pathway. CML therapy, based on tyrosine kinase inhibitors (TKIs), such as imatinib (IM), is highly effective. However, 15% of patients are refractory to IM, where in some cases, 20-30% of patients become resistant. Thus, we suggest the repurposing of ACF in CML after IM failure or in combination with IM to improve the anti-tumor effects of IM. In this review, we present the different pharmacological properties of ACF along with its anti-leukemic effects in the hope of its repurposing in CML therapy.

Topics: Acriflavine; Apoptosis; Drug Repositioning; Drug Resistance, Neoplasm; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Protein Kinase Inhibitors

Acriflavine (ACF) is an antiseptic with anticancer properties, blocking the growth of solid and haematopoietic tumour cells. Moreover, this compound has been also shown to overcome the resistance of cancer cells to chemotherapeutic agents. ACF has been shown to target hypoxia-inducible factors (HIFs) activity, which are key effectors of hypoxia-mediated chemoresistance. In this study, we showed that ACF inhibits the growth and survival of chronic myeloid leukaemia (CML) and acute myeloid leukaemia (AML) cell lines in normoxic conditions. We further demonstrated that ACF down-regulates STAT5 expression in CML and AML cells but activates STAT3 in CML cells in a HIF-independent manner. In addition, we demonstrated that ACF suppresses the resistance of CML cells to tyrosine kinase inhibitors, such as imatinib. Our data suggest that the dual effect of ACF might be exploited to eradicate de novo or acquired resistance of myeloid leukaemia cells to chemotherapy.

Topics: Acriflavine; Antineoplastic Agents; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Drug Resistance, Neoplasm; Humans; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Protein Kinase Inhibitors; Signal Transduction; STAT5 Transcription Factor; Tumor Suppressor Proteins

Chronic myeloid leukemia (CML) is a hematopoietic stem cell (HSC)-driven neoplasia characterized by expression of the constitutively active tyrosine kinase BCR/Abl. CML therapy based on tyrosine kinase inhibitors (TKIs) is highly effective in inducing remission but not in targeting leukemia stem cells (LSCs), which sustain minimal residual disease and are responsible for CML relapse following discontinuation of treatment. The identification of molecules capable of targeting LSCs appears therefore of primary importance to aim at CML eradication. LSCs home in bone marrow areas at low oxygen tension, where HSCs are physiologically hosted. This study addresses the effects of pharmacological inhibition of hypoxia-inducible factor-1 (HIF-1), a critical regulator of LSC survival, on the maintenance of CML stem cell potential. We found that the HIF-1 inhibitor acriflavine (ACF) decreased survival and growth of CML cells. These effects were paralleled by decreased expression of c-Myc and stemness-related genes. Using different in vitro stem cell assays, we showed that ACF, but not TKIs, targets the stem cell potential of CML cells, including primary cells explanted from 12 CML patients. Moreover, in a murine CML model, ACF decreased leukemia development and reduced LSC maintenance. Importantly, ACF exhibited significantly less-severe effects on non-CML hematopoietic cells in vitro and in vivo. Thus, we propose ACF, a US Food and Drug Administration (FDA)-approved drug for nononcological use in humans, as a novel therapeutic approach to prevent CML relapse and, in combination with TKIs, enhance induction of remission.

Topics: Acriflavine; Animals; Cell Survival; Drug Delivery Systems; Humans; Hypoxia-Inducible Factor 1; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mice; Neoplasm Proteins; Neoplasms, Experimental; Neoplastic Stem Cells; NIH 3T3 Cells