Intracellular expression of arginine deiminase activates the mitochondrial apoptosis pathway by inhibiting cytosolic ferritin and inducing chromatin autophagy

Abstract

Background: Based on its low toxicity, arginine starvation therapy has the potential to cure malignant tumors that cannot be treated surgically. The Arginine deiminase (ADI) gene has been identified to be an ideal cancersuppressor gene. ADI expressed in the 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 mechanism of action as ADI-PEG20 or other underlying cellular mechanisms. Methods: The interactions of ADI with other protein factors were screened by yeast hybrids, and verified by coimmunoprecipitation and immunofluorescent staining. The effect of ADI inhibiting the ferritin light-chain domain (FTL) in mitochondrial damage was evaluated by site-directed mutation and flow cytometry. Control of the mitochondrial apoptosis pathway was analyzed by Western Blotting and real-time PCR experiments. The effect of p53 expression on cancer cells death was assessed by siTP53 transfection. Chromatin autophagy was explored by immunofluorescent staining and Western Blotting. Results: ADI expressed in the cytosol inhibited the activity of cytosolic ferritin by interacting with FTL. The inactive mutant of ADI still induced apoptosis in certain cell lines of ASS-through mitochondrial damage. Arginine starvation also generated an increase in the expression of p53 and p53AIP1, which aggravated the cellular mitochondrial damage. Chromatin autophagy appeared at a later stage of arginine starvation. DNA damage occurred along with the entire arginine starvation process. Histone 3 (H3) was found in autophagosomes, which implies that cancer cells attempted to utilize the arginine present in histones to survive during arginine starvation. Conclusions: Mitochondrial damage is the major mechanism of cell death induced by cytosolic ADI. The process of chromatophagy does not only stimulate cancer cells to utilize histone arginine but also speeds up cancer cell death at a later stage of arginine starvation.

Arginine Signaling and Cancer Metabolism

“…This, coupled with ROS-induced DNA damage, leads to chromatin-autophagy or chromatophagy, where autolysosome fused with nuclear membrane and “extracts” broken chromatin out of nucleus [ 16 ], eventually leading to caspase-independent cell death. This was observed in prostate cancer cells [ 16 ], breast cancer cells [ 15 ]; hepatocellular carcinoma cells [ 120 ] and pancreatic cells [ 121 ].…”

Arginine Is a Novel Drug Target for Arginine Decarboxylase in Human Colorectal Cancer Cells

“…Previous research has indicated that arginine starvation can induce apoptosis in cells, triggering stress responses due to the absence of arginine. This not only leads to cell cycle arrest, but also activates pathways leading to apoptosis [ 28 , 29 , 30 ]. As such, we have further investigated the specific apoptosis pathway induced by ADC.…”

Arginine regulates HSPA5/BiP translation through ribosome pausing in triple-negative breast cancer cells

“…Both in vivo and in vitro studies in TNBC have shown that arginine shortage impairs mitochondrial function, induces endoplasmic reticulum (ER) stress response, and causes tumour cell death [ 9 , 11 ]. While the effects of arginine shortage on mitochondrial function are fairly well understood [ 10 , 12 – 15 ], the underlying molecular mechanisms controlling the ER stress response to acute arginine withdrawal remain to be elucidated [ 10 , 12 , 13 ].…”