Piplartine eliminates CD34+ AML stem/progenitor cells by inducing oxidative stress and suppressing NF-κB signalling

Data availability: Data will be made available on request.Supplementary information is available online at: https://www.nature.com/articles/s41420-024-01909-4#Sec20 .Author notes: These authors contributed equally: Cristina Pina, Daniel P. Bezerra.Acute myeloid leukaemia (AML) is a haematological malignancy characterised by the accumulation of transformed myeloid progenitors in the bone marrow. Piplartine (PL), also known as piperlongumine, is a pro-oxidant small molecule extracted from peppers that has demonstrated antineoplastic potential in solid tumours and other haematological malignancies. In this work, we explored the potential of PL to treat AML through the use of a combination of cellular and molecular analyses of primary and cultured leukaemia cells in vitro and in vivo. We showed that PL exhibits in vitro cytotoxicity against AML cells, including CD34+ leukaemia-propagating cells, but not healthy haematopoietic progenitors, suggesting anti-leukaemia selectivity. Mechanistically, PL treatment increased reactive oxygen species (ROS) levels and induced ROS-mediated apoptosis in AML cells, which could be prevented by treatment with the antioxidant scavenger N-acetyl-cysteine and the pancaspase inhibitor Z-VAD(OMe)-FMK. PL treatment reduced NFKB1 gene transcription and the level of NF-κB p65 (pS536), which was depleted from the nucleus of AML cells, indicating suppression of NF-κB p65 signalling. Significantly, PL suppressed AML development in a mouse xenograft model, and its combination with current AML treatments (cytarabine, daunorubicin and azacytidine) had synergistic effects, indicating translational therapeutic potential. Taken together, these data position PL as a novel anti-AML candidate drug that can target leukaemia stem/progenitors and is amenable to combinatorial therapeutic strategies.This work received financial support and fellowships from the Brazilian agencies Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil) and Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB, Brazil). Work in the Pina lab was funded by a British Society for Haematology Early-stage Research Grant (33932) and a BRIEF award by Brunel University London (2020–2022)

Endogenous interleukin-4 downregulates the type 1 CD4 T cell-mediated immune response induced by intramuscular DNA immunization

Intramuscular (i.m.) administration of eukaryotic plasmid vectors containing foreign genes is a general immunization strategy capable of inducing protective type 1 immune responses against viral, bacterial, fungal, and parasitic infections. We have described that immunization with a plasmid containing a gene encoding a parasite antigen elicits specific type 1 protective immune responses against experimental infection with the human protozoan parasite Trypanosoma cruzi. However, we had evidence suggesting that DNA immunization concomitantly activated specific type 2 immune responses. To determine precisely the influence of the type 2 cytokine interleukin-4 (IL-4) during DNA immunization, we compared the immune responses of genetically modified IL-4-deficient or wild-type (wt) BALB/c mice. IL-4-deficient mice had a significantly lower ratio of specific serum IgG1/IgG2a, and on in vitro restimulation with antigen, their spleen cells secreted significantly higher amounts of interferon-gamma (IFN-gamma). in contrast, absence of IL-4 did not affect total serum antibody response, T cell proliferative responses, or activation of IFN-gamma-producing CD8(+) T cells. Our results suggested that in contrast to conventional adjuvants, such as alum and complete Freund's adjuvant, specific IgG1 in DNA-immunized BALB/c mice was highly dependent on IL-4. To our knowledge, our study provides the first evidence that endogenous IL-4 selectively downregulates the type 1 CD4(+) T cell-mediated immune response induced by i.m. genetic immunization, a fact that may have implications for the design of certain DNA vaccines.UNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilFdn Oswaldo Cruz, Ctr Pesquisas Goncalo Moniz, BR-40295001 Salvador, BA, BrazilUNIFESP, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc