Oridonin Inhibits the Occurrence and Development of Colorectal Cancer by Reversing the Warburg Effect via Reducing Pkm2 Dimer Formation and Preventing Its Entry into the Nucleus

Abstract

Abstract: Background: The Warburg effect is prevalent in human cancer. Oridonin (ORI) has
excellent anticancer effects, but its exact anticancer mechanism is still unclear.
Methods: CCK8, EdU, and flow cytometry assay were performed to detect the effect of ORI on cell
viability, proliferation and apoptosis, respectively. RNA-seq was carried out to search the
underlying mechanisms. Total PKM2, dimeric PKM2, nuclear PKM2 was detected by Western
blot. The epidermal growth factor receptor/extracellular signal regulated kinase (EGFR/ERK)
signaling was assayed. The binding ability of Importin-α5 to
PKM2 was performed by Co-IP experiments. The effect of ORI combined with cysteine (Cys) or
fructose-1, 6- diphosphate (FDP) on cancer cells was detected. Mouse xenograft model was
established to confirm the mo- lecular mechanisms in vivo.
Results: ORI inhibited viability, proliferation and promoted apoptosis of CRC cells. RNA-seq
revealed ORI attenuated the Warburg effect in cancer cells. ORI reduced dimeric PKM2 and
prevented it from entering the nucleus. ORI did not affect the EGFR/ERK signaling, but reduced
Importin-α5 binding to the PKM2 dimer. Cys or FDP reversed or enhanced the effect of ORI.
Animal model assay confirmed the molecular mechanisms in vivo.
Conclusions: Our study first shows that ORI could have anticancer activity by inhibiting the
Warburg effect as a novel activator of PKM2