Abstract
Background：Based on its low toxicity, arginine starvation therapy has the potential to treat those malignant tumors that can’t be treated by surgery. Arginine deiminase (ADI) gene is indicated to be an ideal cancer-suppressor gene. ADI expressed in cytosol displays higher oncolytic efficiency than ADI-PEG20 (Pegylated Arginine Deiminase by PEG 20,000). However, it is still unknown whether cytosolic ADI has the same function mechanism as ADI-PEG20 or other underlying mechanisms in cells.Methods: The interaction of ADI and other protein factors was screened by yeast hybrid, and verified by co-immunoprecipitation and immunofluorescent staining. The effect of ADI inhibiting ferritin light-chain domain (FTL) on mitochondrial damage was evaluated by site-directed mutation and flow cytometry. The apoptosis pathway of mitochondria control was analyzed by Western Blot and real-time PCR experiments. The effect of p53 expression on cancer cell death was assessed by siTP53 transfection. The chromatin autophagy was explored by immunofluorescent staining and Western Blot.Results: ADI expressed in cytosol inhibited the activity of cytosolic ferritin through interacting with FTL. The inactive mutant of ADI still induced the apoptosis in certain cell lines of ASS- through mitochondrial damage. Arginine starvation also induced the increased expression of p53 and p53AIP1, which aggravate cellular mitochondrial damage. Chromatin autophagy appeared at the later stage of arginine starvation. DNA damage came along with the whole process of arginine starvation. Histone 3 (H3) was found in autophagosomes, which implied that cancer cells try to utilize the arginine in histones to survive during arginine starvation. Conclusions: Mitochondrial damage is the major mechanism of cell death induced by cytosolic ADI. Chromatophagy accumulations not only drive cancer cell to utilize histone arginine but also speed up cancer cell death at the later time point of arginine starvation.
A small library of chalcones induce liver cancer cell death through Akt phosphorylation inhibition
