The expression level of hypoxia-related proteins (hypoxia-inducible factor [HIF]-1α and Notch-1) and apoptosis-related proteins (B cell lymphoma [Bcl]-2, Bax, and caspase-3) were evaluated by Western blot analysis.
Of the DEGs in day 2 and 6 fractured samples, various upregulated DEGs, including protein kinase C α (Prkca) and B‑cell lymphoma antagonist/killer 1 were significantly enriched in GO terms associated with cell death, and certain downregulated DEGs, including fms‑related tyrosine kinase 1 (Flt1), nitric oxide synthase 3 (Nos3), bone morphogenetic protein 4 (Bmp4) and Notch1 were enriched in GO terms associated with angiogenesis.
The protein levels of Nox4, Notch1, Notch intracellular domain 1 (NICD1), phosphorylated (p) Ras‑related C3 botulinum toxin substrate 1 (Rac1), Rac1, B‑cell lymphoma 2 apoptosis regulator (Bcl‑2), Bcl‑2 associated protein X apoptosis regulator (Bax) and cleaved caspase‑3 were determined by western blotting.
In addition, reverse transcription quantitative polymerase chain reaction and western blot analysis revealed that simvastatin‑treated cells exhibited increased expression levles of Notch1, p53, and Bax, as well as decreased expression levels of B cell lymphoma 2; furthermore, Notch1 upregulation resulted in the inhibition of Akt phosphorylation.
Induced activation through any of the Notch receptors (Notch1-4), or through the Notch target Hairy/Enhancer of Split 1 (HES1), consistently leads to AML growth arrest and caspase-dependent apoptosis, which are associated with B cell lymphoma 2 (BCL2) loss and enhanced p53/p21 expression.