Vitamin D3 and its active compound calcitriol inhibits leukemia through the CHAC1-mediated NOTCH1 downregulation

ABSTRACT: Background: Vitamin D3 (VD3), a crucial fat-soluble vitamin, primarily exists in the form of calcitriol, a steroid hormone. Both exhibit anti-neoplastic activity towards several types of cancer, although the underlying mechanism is still not fully understood. Herein, we investigated the mechanism of inhibition of erytho-leukemogenesis by VD3 and calcitriol. Methods: RNAseq analysis was used to explore the effect of VD3 and calcitriol on gene expression in leukemic cells. An animal model of erythro-leukemia was used to test the effect of both compounds in vivo. CHAC1 and VDR expression was knocked-downed in leukemia cells (genotype of the samples: chac1/vdr knockdown) via lentivirus-shRNA. CHAC1 expression was overexpressed in leukemia cells (genotype of the samples: chac1 overexpression) via lentivirus-RNA. Western blotting, RT-qPCR, cell cycle analysis and apoptosis assays were used to determine the effect of VD3 and calcitriol-induced growth suppression in leukemic cells in vitro. Results: VD3 and calcitriol treatment strongly inhibited cancer progression in a mouse model of erythroleukemia induced by the Friend virus. In tissue culture, VD3 and calcitriol inhibited cell proliferation of leukemia cell lines. This leukemic inhibition was associated with the induction of G1 phase cell cycle arrest and apoptosis. Interestingly, RNAseq analysis supported by RT-qPCR revealed that both VD3 and calcitriol induced most known genes associated with the metabolic pathway in leukemic cells. The transcription of the VD3 receptor VDR is strongly induced by both VD3 and calcitriol treated cells. However, leukemia growth suppression by VD3/CA is shown to be independent of the activation of VDR. However, these compounds appeared to suppress the oncogene NOTCH1 by upregulating the cytosolic glutathione degradase CHAC1. Accordingly, lentivirus-mediated knockdown of CHAC1 antagonized leukemia cell suppression induced by VD3 and calcitriol, associated with higher NOTCH1 activation compared to control. Lentivirus-mediated overexpression of CHAC1 suppressed leukemia cell growth and inhibited the expression of NOTCH1. Additionally, glutathione antagonized leukemia cell suppression induced by VD3 and calcitriol, suggesting further that VD3 and calcitriol may inhibit the proliferation of leukemic cells by regulating the CHAC1 pathway. Conclusions: These results demonstrated strong anti-leukemia activity of VD3 and Calcitriol. Moreover, the above results implicated CHAC1-mediated NOTCH1 suppression as the mechanism of leukemia cell growth inhibition by VD3 and calcitriol.

ORGANISM(S): Homo sapiens

PROVIDER: GSE270534 | GEO | 2025/07/01

REPOSITORIES: GEO