Oridonin induces NPM mutant protein translocation and apoptosis in NPM1c+ acute myeloid leukemia cells in vitro

Abstract

Aim: Skewed cytoplasmic accumulation of NPM mutant protein (NPM1c+) is close related to leukemia pathogenesis. The aim of this study was to investigate whether oridonin, a diterpenoid isolated from the Chinese traditional medicine Rabdosia rubescens, was able to interfere with NPM1c+ protein trafficking and induce apoptosis in NPM1c+ acute myeloid leukemia cells in vitro. Methods: OCI-AML3 cell line harboring a NPM1 gene mutation was examined. Cell growth was detected by MTT assay. Cell apoptosis was evaluated using flow cytometry and Hoechst 33258 staining. The expression and subcellular localization of relevant proteins were detected by Western blot and immunofluorescent staining. The mRNA expression was detected by RT-PCR. Results: Oridonin (2-12 μmol/L) dose-dependently inhibited the viability of OCI-AML3 cells (the IC 50 value was 3.27±0.23 μmol/L at 24 h). Moreover, oridonin induced OCI-AML3 cell apoptosis accompanied by activation of caspase-3 and nuclear translocation of NPM1c+ protein. Oridonin did not change the expression of Crm1 (the export receptor for nuclear export signal-containing proteins), but induced nuclear translocation of Crm1. Oridonin markedly increased the expression of nucleoporin98 (Nup98), which had an important role in Crm1-mediated nuclear protein export, and induced nuclear accumulation of Nup98. Furthermore, oridonin markedly increased the expression of p14arf and p53. Conclusion: In NPM1c+ leukemia cells, oridonin induces NPM1c+ protein translocation into the nucleus possibly via nuclear accumulation of Crm1; the compound markedly increases p53 and p14arf expression, which may contribute to cell apoptosis.

Natural products against hematological malignancies and identification of their targets

“…Oridonin was also shown to kill some lymphoid malignancies, including multiple myeloma, adult T-cell leukemia and non-Hodgkin's lymphoma (NHL), possibly mediated by inhibition of the DNA-binding activity of NF-B [59]. The natural compound also dosedependently induced apoptosis of the OCI-AML3 cell line harboring nucleophosmin (NPM) 1 mutations [60]. This is the most common genetic lesion in adult AML patients, accounting for 60% of cases with a normal karyotype and causes the skewed cytoplasmic accumulation of the NPM mutant protein (NPM1c + ), which is thought to be responsible for leukemia pathogenesis.…”

“…This is the most common genetic lesion in adult AML patients, accounting for 60% of cases with a normal karyotype and causes the skewed cytoplasmic accumulation of the NPM mutant protein (NPM1c + ), which is thought to be responsible for leukemia pathogenesis. The oridonin-induced apoptosis is accompanied by activation of caspase-3 and nuclear translocation of the NPM1c + protein [60]. However, the direct target of oridonin responsible for the alteration of NPM1 mutant localization is currently unknown.…”

Engineering chromosome region maintenance 1 fragments that bind to nuclear export signals

“…CRM1 inhibitors demonstrated promising potential in preclinical or clinical trials . Several CRM1 inhibitors were derived from plants including, piperlongumine (PIP), oridonin (ORI), valtrate (VAL), acetoxychavicol acetate (ACA), goniothalamin, plumbagin (PLU), sulforaphene, caffeic acid phenethyl ester, and curcumin (CUR) . Though these reports all demonstrated inhibition of CRM1 cargo's export through cellular assays, none used purified proteins to demonstrate their direct binding such as using pull‐down assays.…”

Oridonin induces Mdm2‐p60 to promote p53‐mediated apoptosis and cell cycle arrest in neuroblastoma

“…[17][18][19][20] It is especially crucial that several studies have shown that during the apoptosis of cancer cells induced by oridonin or its derivatives, p53 is reactivated and the proteins on the downstream of p53 are also altered. 20,21 For example, oridonin induces the growth inhibition and apoptosis of gastric cancer cells by regulating the expression and function of p53 22 ; the anticancer effects of oridonin on colon cancer cells are mediated through BMP7/ p38 MAPK/p53 signaling pathway 23 ; Geridonin, a derivative of oridonin, in combination with paclitaxel can lead to the accumulation of p53, and further apoptosis of gastric cancer cells by the mitochondrial pathway. 24 Furthermore, the apoptosis and autophagy of murine fibrosarcoma cells induced by oridonin are also p53-dependent.…”