Natural compounds and pharmaceuticals reprogram leukemia cell differentiation pathways. Morceau Franck,Chateauvieux Sébastien,Orsini Marion,Trécul Anne,Dicato Mario,Diederich Marc Biotechnology advances In addition to apoptosis resistance and cell proliferation capacities, the undifferentiated state also characterizes most cancer cells, especially leukemia cells. Cell differentiation is a multifaceted process that depends on complex regulatory networks that involve transcriptional, post-transcriptional and epigenetic regulation of gene expression. The time- and spatially-dependent expression of lineage-specific genes and genes that control cell growth and cell death is implicated in the process of maturation. The induction of cancer cell differentiation is considered an alternative approach to elicit cell death and proliferation arrest. Differentiation therapy has mainly been developed to treat acute myeloid leukemia, notably with all-trans retinoic acid (ATRA). Numerous molecules from diverse natural or synthetic origins are effective alone or in association with ATRA in both in vitro and in vivo experiments. During the last two decades, pharmaceuticals and natural compounds with various chemical structures, including alkaloids, flavonoids and polyphenols, were identified as potential differentiating agents of hematopoietic pathways and osteogenesis. 10.1016/j.biotechadv.2015.03.013
    ASLAN003, a potent dihydroorotate dehydrogenase inhibitor for differentiation of acute myeloid leukemia. Zhou Jianbiao,Quah Jessie Yiying,Ng Yvonne,Chooi Jing-Yuan,Toh Sabrina Hui-Min,Lin Baohong,Tan Tuan Zea,Hosoi Hiroki,Osato Motomi,Seet Qihui,Ooi A G Lisa,Lindmark Bertil,McHale Mark,Chng Wee-Joo Haematologica Differentiation therapies achieve remarkable success in acute promyelocytic leukemia, a subtype of acute myeloid leukemia. However, excluding acute promyelocytic leukemia, clinical benefits of differentiation therapies are negligible in acute myeloid leukemia except for mutant isocitrate dehydrogenase 1/2. Dihydroorotate dehydrogenase catalyses the fourth step of the de novo pyrimidine synthesis pathway. ASLAN003 is a highly potent dihydroorotate dehydrogenase inhibitor that induces differentiation, as well as reduces cell proliferation and viability, of acute myeloid leukemia cell lines and primary acute myeloid leukemia blasts including in chemo-resistant cells. Apoptotic pathways are triggered by ASLAN003, and it also significantly inhibits protein synthesis and activates AP-1 transcription, contributing to its differentiation promoting capacity. Finally, ASLAN003 substantially reduces leukemic burden and prolongs survival in acute myeloid leukemia xenograft mice and acute myeloid leukemia patient-derived xenograft models. Notably, the drug has no evident effect on normal hematopoietic cells and exhibits excellent safety profiles in mice, even after a prolonged period of administration. Our results, therefore, suggest that ASLAN003 is an agent targeting dihydroorotate dehydrogenase with potential in the treatment of acute myeloid leukemia. ASLAN003 is currently being evaluated in phase 2a clinical trial in acute myeloid leukemia patients. 10.3324/haematol.2019.230482
    PARI (PARPBP) suppresses replication stress-induced myeloid differentiation in leukemia cells. Nicolae Claudia M,O'Connor Michael J,Schleicher Emily M,Song Chunhua,Gowda Raghavendra,Robertson Gavin,Dovat Sinisa,Moldovan George-Lucian Oncogene Hyperproliferative cancer cells face increased replication stress, which can result in accumulation of DNA damage. As DNA damage can arrest proliferation, and, in the case of myeloid leukemia, induce differentiation of cancer cells, understanding the mechanisms that regulate the replication stress response is paramount. Here, we show that PARI, a replisome protein involved in regulating DNA repair and replication stress, suppresses differentiation of myeloid leukemia cells. We show that PARI is overexpressed in myeloid leukemia cells, and its knockdown reduces leukemia cell proliferation in vitro and in vivo in xenograft mouse models. PARI depletion enhances replication stress and DNA-damage accumulation, coupled with increased myeloid differentiation. Mechanistically, we show that PARI inhibits activation of the NF-κB pathway, which can initiate p21-mediated differentiation and proliferation arrest. Finally, we show that PARI expression negatively correlates with expression of differentiation markers in clinical myeloid leukemia samples, suggesting that targeting PARI may restore differentiation ability of leukemia cells and antagonize their proliferation. 10.1038/s41388-019-0810-x
    Differentiation therapy of myeloid leukemia: four decades of development. Madan Vikas,Koeffler H Phillip Haematologica Acute myeloid leukemia is characterized by arrested differentiation, and agents that overcome this block are therapeutically useful, as shown by the efficacy of all-trans retinoic acid in acute promyelocytic leukemia. However, the early promise of differentiation therapy did not translate into clinical benefit for other subtypes of acute myeloid leukemia, in which cytotoxic chemotherapeutic regimens remained the standard of care. Recent advances, including insights from sequencing of acute myeloid leukemia genomes, have led to the development of targeted therapies, comprising agents that induce differentiation of leukemic cells in preclinical models and clinical trials, thus rejuvenating interest in differentiation therapy. These agents act on various cellular processes including dysregulated metabolic programs, signaling pathways, epigenetic machinery and the cell cycle. In particular, inhibitors of mutant IDH1/2 and FLT3 have shown clinical benefit, leading to approval by regulatory bodies of their use. Besides the focus on recently approved differentiation therapies, this review also provides an overview of differentiation- inducing agents being tested in clinical trials or investigated in preclinical research. Combinatorial strategies are currently being tested for several agents (inhibitors of KDM1A, DOT1L, BET proteins, histone deacetylases), which were not effective in clinical studies as single agents, despite encouraging anti-leukemic activity observed in preclinical models. Overall, recently approved drugs and new investigational agents being developed highlight the merits of differentiation therapy; and ongoing studies promise further advances in the treatment of acute myeloid leukemia in the near future. 10.3324/haematol.2020.262121
    Targeting the thioredoxin system as a novel strategy against B-cell acute lymphoblastic leukemia. Fidyt Klaudyna,Pastorczak Agata,Goral Agnieszka,Szczygiel Kacper,Fendler Wojciech,Muchowicz Angelika,Bartlomiejczyk Marcin Adam,Madzio Joanna,Cyran Julia,Graczyk-Jarzynka Agnieszka,Jansen Eugene,Patkowska Elzbieta,Lech-Maranda Ewa,Pal Deepali,Blair Helen,Burdzinska Anna,Pedzisz Piotr,Glodkowska-Mrowka Eliza,Demkow Urszula,Gawle-Krawczyk Karolina,Matysiak Michal,Winiarska Magdalena,Juszczynski Przemyslaw,Mlynarski Wojciech,Heidenreich Olaf,Golab Jakub,Firczuk Malgorzata Molecular oncology B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a genetically heterogeneous blood cancer characterized by abnormal expansion of immature B cells. Although intensive chemotherapy provides high cure rates in a majority of patients, subtypes harboring certain genetic lesions, such as MLL rearrangements or BCR-ABL1 fusion, remain clinically challenging, necessitating a search for other therapeutic approaches. Herein, we aimed to validate antioxidant enzymes of the thioredoxin system as potential therapeutic targets in BCP-ALL. We observed oxidative stress along with aberrant expression of the enzymes associated with the activity of thioredoxin antioxidant system in BCP-ALL cells. Moreover, we found that auranofin and adenanthin, inhibitors of the thioredoxin system antioxidant enzymes, effectively kill BCP-ALL cell lines and pediatric and adult BCP-ALL primary cells, including primary cells cocultured with bone marrow-derived stem cells. Furthermore, auranofin delayed the progression of leukemia in MLL-rearranged patient-derived xenograft model and prolonged the survival of leukemic NSG mice. Our results unveil the thioredoxin system as a novel target for BCP-ALL therapy, and indicate that further studies assessing the anticancer efficacy of combinations of thioredoxin system inhibitors with conventional anti-BCP-ALL drugs should be continued. 10.1002/1878-0261.12476