Ubenimex, an APN inhibitor, could serve as an anti‑tumor drug in RT112 and 5637 cells by operating in an Akt‑associated manner

Abstract

Bladder cancer, a common urinary tract tumor, has high mortality and recurrence rates associated with metastasis. Aminopeptidase N (APN) expression and metastasis have been indicated to be associated with one another. Ubenimex may function as an APN inhibitor to inhibit the degradation of the extracellular matrix during tumorigenesis. Furthermore, APN has been widely used as an adjuvant therapy for the treatment of tumors; however, little information is available regarding the impact of ubenimex on patients. Autophagy is suggested to be important in the transformation and progression of cancer. Additionally, apoptosis, which leads to the rapid demolition of cellular organelles and structures, has also been suggested as an important factor. Thus, the present study investigated the role of ubenimex in inhibiting migration and invasion by downregulating APN expression levels to induce autophagic cell death and apoptosis in bladder cancer cells. RT112 and 5637 cell lines were treated with varying doses of ubenimex. Cell viability was measured by CCK8 colorimetry and flow cytometry. Using fluorescence microscopy, autophagic cell death was assessed using acridine orange/ethidium bromide staining. Furthermore, apoptotic cell death was assessed using flow cytometry and Trypan blue staining was used to evaluate the cell death rate. Protein expression was determined by western blot analysis. Matrigel invasion assays were exploited to assess the invasion capabilities of 5637 cells. Wound-healing migration assays and Matrigel migration assays were exploited to assess the migratory abilities of 5637 cells. Treatment with ubenimex was accompanied by decreased Akt expression, indicating that ubenimex may have similar functions to Akt inhibitors. Results also indicated that ubenimex inhibited cell migration and invasion in bladder cancer cells. Furthermore, ubenimex also induced autophagic cell death and apoptosis, which suggested that mixed programmed cell death occurred in ubenimex-treated bladder cancer cells. The results from the present study suggest that ubenimex may be a potential adjuvant therapy for the treatment of bladder cancer.

Autophagy modulation in bladder cancer development and treatment (Review)

“…On the basis of this concept, a number of studies have been performed to investigate the therapeutic potential of autophagic cell death activation in different fields of cancer treatment. In BC, autophagic cell death has been noted in chemotherapy with pazopanib (57), biological therapy with Cheliensisine A-fluoride (ChlA-F) (58) and with alternative therapies (59,60,75) (Table II).…”

“…Therefore, as an APN inhibitor, ubenimex is a promising agent for cancer treatment. Ubenimex has been shown to inhibit the proliferation, migration and invasion of BC cells by downregulating APN expression levels and inducing autophagy through inhibition of the Akt signaling pathway (75). On the contrary, autophagy inhibition with 3-MA reversed the antiproliferative properties of ubenimex, indicating that ubenimex was capable of inducing autophagic cell death in BC cells (75).…”

<p>Ubenimex induces apoptotic and autophagic cell death in rat GH3 and MMQ cells through the ROS/ERK pathway</p>

“…Previous studies have demonstrated that ubenimex can induce not only apoptosis but also autophagic cell death in malignant melanoma and bladder cancer cells 22,23. In the present study, we directly detected autophagosome formation by transmission electron microscopy.…”

“…Previous reports have found that ubenimex shows cytotoxicity and suppresses cell proliferation in leukaemia cell lines,27 glioma,28 malignant melanoma and bladder cancer 22,23. In addition, ubenimex can also synergistically enhance the efficacy of anticancer drugs in many human tumour-derived cell lines, such as those from hepatocellular carcinoma and osteosarcoma 29–31.…”

New directions of activity-based sensing forin vivoNIR imaging

“…62 APN is a cell membrane protein that is responsible for digesting peptides generated by gastric and pancreatic proteases. 63 Due to its extracellular localization and overexpression in bladder cancer (BC), 64,65 APN activity is an attractive target for the diagnosis and staging of BC. Other NIR-I dyes have been reported for APN, 66,67 but in addition to the APN trigger and a NIR-I dye, the probe developed by the authors (CyP1) is also equipped with a renal clearance moiety (Fig.…”