CD13 inhibition augments DR4-induced tumor cell death in a p-ERK1/2-independent manner

Abstract

Objective: Death receptor 4 (DR4; TRAIL-R1) critically mediates extrinsic apoptosis cascades via binding to TNF-related apoptosis-inducing ligand (TRAIL). However, intrinsic and/or acquired resistance are observed in the clinical application of TRAIL. The aim of this study was to investigate the function and molecular mechanism of CD13 in the TRAIL/DR4 pathway against tumor cells, and provide a new strategy for improving therapeutic efficacy or overcoming TRAIL-resistance. Methods: TRAIL protein was expressed as a secretory protein in a Pichia pastoris expression system and was isolated and purified by affinity chromatography. The cell viability and apoptosis were evaluated with MTT (thiazolyl blue tetrazolium bromide) assays and annexin V-FITC/PI staining with flow cytometry analysis, respectively. Western blot analysis was used to detect the levels of the indicated proteins in tumor cells. DR4 degradation or stability was examined with cycloheximide chase assays, and cell surface DR4 was assessed with flow cytometric analysis after staining with a FITC-conjugated antibody. The effects of cell migration were determined with Transwell and gelatin zymography assays. A xenograft nude mouse model was used to detect the anti-tumor effect in vivo, and the proliferation in tumor tissues was examined with immunohistochemical staining. Results: CD13 inhibition potently sensitized tumor cells to TRAIL-induced killing, including proliferation inhibition, increased apoptosis, and migration suppression. In addition, the inhibition of CD13 elevated both total cellular expression and cell surface DR4 through stabilizing DR4 by suppressing its degradation. DR4 siRNA attenuated the enhanced anti-tumor effects of TRAIL plus CD13 inhibition. Interestingly, these phenomena were p-ERK1/2 independent, although p-ERK1/2 down-regulation was tightly correlated with the cooperation of TRAIL and CD13 inhibition. Moreover, a synergistic decrease in tumor growth was surprisingly achieved in the xenograft model by treatment of TRAIL with a CD13 inhibitor (**P < 0.01, CDI = 0.47). Conclusions: CD13 inhibition cooperates with TRAIL in enhancing DR4-mediated cell death, through the up-regulation and stabilization of DR4 in a p-ERK1/2-independent manner. Thus CD13 inhibition has emerged as an effective strategy for TRAIL/ DR4-based therapy.

Marine Invertebrates: A Promissory Still Unexplored Source of Inhibitors of Biomedically Relevant Metallo Aminopeptidases Belonging to the M1 and M17 Families

“…Dysregulation of APN expression evolves in almost all types of human malignancies, including breast cancer, cervical cancer, ovarian cancer, prostate cancer, non-small-cell lung cancer (NSCLC), liver cancer, colon cancer, cirrhosis gastric cancer, pancreatic cancer, renal cell carcinoma (RCC), hepatocellular carcinoma (HCC), head and neck squamous cell carcinoma (SCC), melanoma, osteosarcoma, and thyroid cancer [ 19 , 91 ]. This makes human APN an attractive target for the treatment of diseases, including cancers ( Figure 11 ) [ 8 , 18 , 19 , 91 , 92 , 93 ]. Accordingly, strategies for its inhibition have been developed primarily for the treatment of pain [ 94 , 95 ].…”

Non‐oxidized and oxidized flaxseed orbitides differently induce HepG2 cell apoptosis: involvement of cellular uptake and membrane death receptor DR4

“…20 DR4 is overexpressed in a variety of tumor cells (in higher abundance), and it has been claimed that natural phytochemicals can accelerate the DR4-mediated apoptotic pathway. 21 In our previous study, non-oxidized flaxseed orbitides (CLA and CLB) were found to trigger apoptosis primarily through the death receptor DR4, 16 whereas it is unknown whether DR4 is responsible for the lower anti-cancer ability of oxidized flaxseed orbitides compared to non-oxidized flaxseed orbitides.…”

“…Death receptor 4 (DR4; also known as TRAIL‐R1) is a member of the DR subgroup of the tumor necrosis factor (TNF) receptor superfamily, and it contains the death domain in its intracellular portion, which signals for apoptosis 20 . DR4 is overexpressed in a variety of tumor cells (in higher abundance), and it has been claimed that natural phytochemicals can accelerate the DR4‐mediated apoptotic pathway 21 . In our previous study, non‐oxidized flaxseed orbitides (CLA and CLB) were found to trigger apoptosis primarily through the death receptor DR4, 16 whereas it is unknown whether DR4 is responsible for the lower anti‐cancer ability of oxidized flaxseed orbitides compared to non‐oxidized flaxseed orbitides.…”

Thymidine Kinase 1 Mediates the Synergistic Antitumor Activity of Ubenimex and Celecoxib via Regulation of Cell Cycle in Colorectal Cancer

“…Ubenimex, an approved drug for adjuvant therapy in cancer patients with good safety, exerts antitumor activities via regulation of the immune response and direct inhibitory activity against tumor cells through binding to aminopeptidase (CD13) on the surface of immune cells and tumor cells (Ni et al, 2021). It reduces tumor cell growth and causes cell apoptosis, prevents tumor cell invasion and metastasis, and inhibits angiogenesis in tumors by inhibiting CD13 activity (Ni et al, 2018).…”