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

Bestatin attenuates breast cancer stemness by targeting puromycin-sensitive aminopeptidase

Breast cancer is a prevalent malignant tumor among women with an increasing incidence rate annually. Breast cancer stem cells (BCSCs) are integral in impeding tumor advancement and addressing drug resistance. Bestatin serves as an adjuvant chemotherapy, triggering apoptosis in cancer cells. In this study, the effects of bestatin on sorted BCSCs from breast cancer cell lines have been studied. Our results indicated that bestatin inhibits the migration and proliferation of breast cancer cells by reducing the stemness of BCSCs both in vitro and in vivo. Puromycin-sensitive aminopeptidase is implicated in the process through the regulation of cell cycle, resulting in heightened cell apoptosis and diminished cell proliferation of BCSCs. Our study suggest that targeting cancer stem cell may offer a promising approach in breast cancer treatment, presenting noval therapeutic strategies for patients with breast cancer.

Design, Synthesis, and Biological Evaluation of APN and AKT Dual-Target Inhibitors

Herein a novel series of APN and AKT dual inhibitors were derived from the clinical AKT inhibitor AZD5363. It was demonstrated that most compounds exhibited remarkable APN inhibitory activities with the most potent compound 8b (IC₅₀ = 0.05 ± 0.01 μM) being over 70-fold more potent than the approved APN inhibitor bestatin (IC₅₀ = 3.64 ± 0.56 μM). The moderate AKT inhibitory potencies of target compounds were also confirmed, with 5f and 5h possessing AKT1 IC₅₀ values of 0.12 and 0.27 μM, respectively. More importantly, the APN IC₅₀ values of 5f and 5h were 0.96 and 0.21 μM, respectively, indicating their balanced APN and AKT dual inhibition. HUVEC tube formation assays confirmed the superior APN inhibitory activities of 5f and 5h relative to bestatin at the cellular level. Western blot analysis demonstrated that 5h could effectively inhibit the phosphorylation of GSK3β, the intracellular substrate of AKT.

New directions of activity-based sensing for in vivo NIR imaging

In vivo imaging is a powerful approach to study biological processes. Beyond cellular methods, in vivo studies allow for biological stimuli (small molecules or proteins) to be studied in their native environment. This has the potential to aid in the discovery of new biology and guide the development of diagnostics and therapies for diseases. To ensure selectivity and an observable readout, the probe development field is shifting towards activity-based sensing (ABS) approaches and near-infrared (NIR) imaging modalities. This perspective will highlight recent in vivo ABS applications that utilize NIR imaging platforms.

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

Purpose

Ubenimex, an aminopeptidase N (APN) inhibitor, is widely known for its use as an adjunct therapy for cancer therapy. However, in recent studies, it has also conferred antitumour effects in many cancers, but its anticancer mechanism is largely unknown. This study aims to investigate the specific anticancer activities and mechanisms of ubenimex in GH3 and MMQ cells.

Materials and methods

In this study, we investigated the anticancer effects of ubenimex in GH3 and MMQ cells. Cell viability and cell death were assessed by the Cell Counting Kit-8 kit (CCK-8) and a LIVE/DEAD cell imaging kit. Apoptosis and intracellular reactive oxygen species (ROS) generation were assessed by flow cytometry and fluorescence microscopy. Autophagosome formation was detected by transmission electron microscopy, and autophagic flux was measured with mRFP-GFP-LC3 adenoviral transfection. The protein expression level was detected by Western blotting.

Results

The results revealed that treatment with ubenimex induced apoptotic and autophagic cell death in GH3 and MMQ cells, which resulted in decreased viability, an increased proportion of apoptotic cells, and autophagosome formation. Further experiments showed that ubenimex induced ROS generation and activated the ROS/ERK pathway. The ROS scavenger NAC could attenuate ubenimex-induced apoptosis and autophagy.

Conclusion

Our studies revealed that ubenimex exerted anticancer effects by inducing apoptotic and autophagic cell death in GH3 and MMQ cells, rendering it a possible effective adjunctive therapy for pituitary treatment.

Autophagy modulation in bladder cancer development and treatment (Review)

Bladder cancer (BC) is a potentially life-threatening malignancy. Due to a high recurrence rate, frequent surveillance strategies and intravesical drug therapies, BC is considered one of the most expensive tumors to treat. As a fundamental evolutionary catabolic process, autophagy plays an important role in the maintenance of cellular environmental homeostasis by degrading and recycling damaged cytoplasmic components, including macromolecules and organelles. Scientific studies in the last two decades have shown that autophagy acts as a double-edged sword with regard to the treatment of cancer. On one hand, autophagy inhibition is able to increase the sensitivity of cancer cells to treatment, a process known as protective autophagy. On the other hand, autophagy overactivation may lead to cell death, referred to as autophagic cell death, similar to apoptosis. Therefore, it is essential to identify the role of autophagy in cancer cells in order to develop novel therapeutic agents. In addition, autophagy may potentially become a novel therapeutic target in human diseases. In this review, the current knowledge on autophagy modulation in BC development and treatment is summarized.