DNA damage is overcome by TRIP13 overexpression during cisplatin nephrotoxicity

Targeting TRIP13 in favorable histology Wilms tumor with nuclear export inhibitors synergizes with doxorubicin

Wilms tumor (WT) is the most common renal malignancy of childhood. Despite improvements in the overall survival, relapse occurs in ~15% of patients with favorable histology WT (FHWT). Half of these patients will succumb to their disease. Identifying novel targeted therapies remains challenging in part due to the lack of faithful preclinical in vitro models. Here we establish twelve patient-derived WT cell lines and demonstrate that these models faithfully recapitulate WT biology using genomic and transcriptomic techniques. We then perform loss-of-function screens to identify the nuclear export gene, XPO1, as a vulnerability. We find that the FDA approved XPO1 inhibitor, KPT-330, suppresses TRIP13 expression, which is required for survival. We further identify synergy between KPT-330 and doxorubicin, a chemotherapy used in high-risk FHWT. Taken together, we identify XPO1 inhibition with KPT-330 as a potential therapeutic option to treat FHWTs and in combination with doxorubicin, leads to durable remissions in vivo.

WBP2 restrains the lysosomal degradation of GPX4 to inhibit ferroptosis in cisplatin-induced acute kidney injury

Cisplatin is one of the major causes of acute kidney injury (AKI) in clinical practice, and ferroptosis is an essential form of cell death in cisplatin-induced AKI (CP-AKI). WW domain binding protein-2 (WBP2), a molecular chaperon, is involved in the progression of various malignancies, but its role in renal injuries has not been investigated. Our present study employed bioinformatics analysis to identify WBP2 as a potential modulator of AKI and ferroptosis. Preliminary laboratory investigations showed that WBP2, highly expressed in renal proximal tubular cells, was downregulated in CP-AKI. Further studies demonstrated that WBP2 decelerated ferroptosis to alleviate CP-AKI. Mechanistically, WBP2 interacted with glutathione peroxidase 4 (GPX4, a key detoxicating enzyme for ferroptosis) via its PPXY1 motif to inhibit ferroptosis. Furthermore, the in-depth investigations revealed that WBP2 competed with heat shock cognate protein 70 (HSC70) for the binding with the KEFRQ-like motifs of GPX4, leading to the deceleration of chaperon-mediated autophagy of GPX4. All in all, this study indicated the beneficial effect of WBP2 in CP-AKI and its relevance with ferroptosis, thus providing a novel insight into the modulation of ferroptosis in cisplatin-related nephropathy.

Cisplatin-Induced Kidney Toxicity: Potential Roles of Major NAD+-Dependent Enzymes and Plant-Derived Natural Products

Cisplatin is an FDA approved anti-cancer drug that is widely used for the treatment of a variety of solid tumors. However, the severe adverse effects of cisplatin, particularly kidney toxicity, restrict its clinical and medication applications. The major mechanisms of cisplatin-induced renal toxicity involve oxidative stress, inflammation, and renal fibrosis, which are covered in this short review. In particular, we review the underlying mechanisms of cisplatin kidney injury in the context of NAD⁺-dependent redox enzymes including mitochondrial complex I, NAD kinase, CD38, sirtuins, poly-ADP ribosylase polymerase, and nicotinamide nucleotide transhydrogenase (NNT) and their potential contributing roles in the amelioration of cisplatin-induced kidney injury conferred by natural products derived from plants. We also cover general procedures used to create animal models of cisplatin-induced kidney injury involving mice and rats. We highlight the fact that more studies will be needed to dissect the role of each NAD⁺-dependent redox enzyme and its involvement in modulating cisplatin-induced kidney injury, in conjunction with intensive research in NAD⁺ redox biology and the protective effects of natural products against cisplatin-induced kidney injury.

Inhibition of PLK3 Attenuates Tubular Epithelial Cell Apoptosis after Renal Ischemia–Reperfusion Injury by Blocking the ATM/P53-Mediated DNA Damage Response

Objective

Renal ischemia–reperfusion (I/R) injury is a major cause of acute kidney injury (AKI) in transplanted kidneys. This study was aimed at exploring the role of PLK3 (polo-like kinase 3) in renal I/R injury, focusing on its relationship with oxidative stress-induced DNA damage and renal tubular epithelial cell (TEC) apoptosis.

Methods

TRAP-seq data from the development dataset GSE52004 and the validation dataset GSE121191 were analyzed using GEO2R. PLK3 overexpression plasmids and targeted silencing siRNAs were used in a model of hypoxia/reoxygenation (H/R) injury, and rAAV-9-PLK3-KD were administered to C57BL/6J mice exposed to I/R injury. The ATM-specific inhibitor KU-60019 was used to block the DNA damage response (DDR). Western blotting was performed to measure DDR- and apoptosis-associated protein expression. Cell viability was measured by CCK-8 reagent, and apoptosis was examined by flow cytometry and TUNEL assay. Furthermore, the fluorescent probes H₂DCFH-DA and DHE were used to measure ROS production in vitro. The MDA level and SOD activity were measured to assess oxidative stress in vivo. KIM-1 staining and Scr and BUN were used to evaluate kidney injury.

Results

The mRNA and protein levels of PLK3 were markedly increased in the H/R injury and I/R injury models. GO terms showed that PLK3 was mainly involved in oxidative stress and DNA damage after renal I/R injury. Overexpression of PLK3 decreased cell viability and increased apoptosis. In contrast, targeted silencing of PLK3 expression decreased the Bax/Bcl-2 ratio by decreasing P53 phosphorylation, thereby reducing TEC apoptosis. Furthermore, KU-60019 reduced PLK3 activation and DDR-induced apoptosis, while overexpression of PLK3 reversed the mitigating effect of KU-60019 on TEC apoptosis. Similarly, rAAV-9-PLK3 KD mice exhibited a lower rate of TEC apoptosis and milder renal damage after I/R injury.

Conclusion

We demonstrate for the first time that PLK3 is involved in oxidative stress-induced DNA damage and TEC apoptosis in renal I/R injury. Inhibition of PLK3 attenuates TEC apoptosis after I/R injury by blocking the ATM/P53-mediated DDR. Therefore, PLK3 may serve as a potential therapeutic target for ischemic AKI.