Effect of stapled α-helical mastermind like 1 (SAHM1) peptide conjugated with gold nanoparticles toward notch signaling pathway in human leukemia Jurkat cell

Abstract

Currently, cancer is the top cause of death in Thailand and caused by the growth and spreading of abnormal cells in an uncontrolled manner. For T-cell acute lymphoblastic leukemia (T-ALL), it was found that gene of encoding protein Notch is often mutated. In T-ALL, Notch signaling pathway is hyperactivated resulting in uncontrolled cell division. There are many types of cancer treatment such as surgery and chemotherapy but both approaches have serious side effects. Therefore, development of target drug delivery system is needed. In this study, the objective was to develop specific target drug delivery system by using gold nanoparticle (AuNP) as a vector of stapled α-helical peptide from Mastermind-like1 (SAHM1) for inhibition of Notch signaling pathway in T cell leukemia cell line (Jurkat), SAHM1 is smaller than its original protein and rapidly absorbed into cells. In cytotoxicity test by MTT assay, the 50% inhibition concentration (IC50) of SAHM1 against Jurkat cell was 17.54±5.17 µM at 72 h. Conjugation of SAHM1 to AuNP linked by polyethylene glycol (SAHM1-PEG-AuNP) at the concentration of 16.25, 31.3 and 62.5 µM was characterized by UV-Visible spectroscopy. The result showed the shift peak of the conjugate at 527 nm, when compared with the 523 nm peak of 40 nm AuNP. This result indicated that SAHM1 was successfully conjugated to AuNP. In the cytotoxicity test by MTT assay, the cytotoxicity of SAHM1-PEG-AuNP was increased significantly when compared with unconjugated SAHM1. Cellular uptake and localization was detected by transmission electron microscope (TEM). The result demonstrated that SAHM1-PEG-AuNP localized in the cytoplasm of Jurkat cell line, while unconjugated AuNP was found outside of Jurkat cell line. The effect of SAHM1-PEG-AuNP on Notch signaling pathway was measured by qPCR of the Notch target genes (HES1, HEY1 and MYC). The result showed that the mRNA level of Notch target genes in SAHM1-PEG-AuNP treated cells did not significantly decrease. Collectively, these results indicated that AuNP could be used as the cell-penetrating carrier of SAHM1 in order to kill cancer cell lines. This result opens a new way for drug and new cancer treatment in the future.