Skullcapflavone II, a novel NQO1 inhibitor, alleviates aristolochic acid I-induced liver and kidney injury in mice

Stimuli-responsive prodrugs with self-immolative linker for improved cancer therapy

Self-immolative prodrugs have gained significant attention as an innovative approach for targeted cancer therapy. These prodrugs are engineered to release the active anticancer agents in response to specific triggers within the tumor microenvironment, thereby improving therapeutic precision while reducing systemic toxicity. This review focuses on the molecular architecture and design principles of self-immolative prodrugs, emphasizing the role of stimuli-responsive linkers and activation mechanisms that enable controlled drug release. Recent advancements in this field include the development of prodrugs that incorporate targeting moieties for enhanced site-specificity. Moreover, the review discusses the incorporation of targeting moieties to achieve site-specific drug delivery, thereby improving the selectivity of treatment. By summarizing key research from the past five years, this review highlights the potential of self-immolative prodrugs to revolutionize cancer treatment strategies and pave the way for their integration into clinical practice.

In silico-guided synthesis of a new, highly soluble, and anti-melanoma flavone glucoside: Skullcapflavone II-6'-O-β-glucoside

Guided by in silico analysis tools and biotransformation technology, new derivatives of natural compounds with heightened bioactivities can be explored and synthesized efficiently. In this study, in silico data mining and molecular docking analysis predicted that glucosides of skullcapflavone II (SKII) were new flavonoid compounds and had higher binding potential to oncogenic proteins than SKII. These benefits guided us to perform glycosylation of SKII by utilizing four glycoside hydrolases and five glycosyltransferases (GTs). Findings unveiled that exclusive glycosylation of SKII was achieved solely through the action of GTs, with Bacillus subtilis BsUGT489 exhibiting the highest catalytic glycosylation efficacy. Structure analysis determined the glycosylated product as a novel compound, skullcapflavone II-6'-O-β-glucoside (SKII-G). Significantly, the aqueous solubility of SKII-G exceeded its precursor, SKII, by 272-fold. Furthermore, SKII-G demonstrated noteworthy anti-melanoma activity against human A2058 cells, exhibiting an IC50 value surpassing that of SKII by 1.4-fold. Intriguingly, no substantial cytotoxic effects were observed in a murine macrophage cell line, RAW 264.7. This promising anti-melanoma activity without adverse effects on macrophages suggests that SKII-G could be a potential candidate for further preclinical and clinical studies. The in silico tool-guided synthesis of a new, highly soluble, and potent anti-melanoma glucoside, SKII-G, provides a rational design to facilitate the future discovery of new and bioactive compounds.

Study on the mechanism of hepatotoxicity of Aucklandiae radix through liver metabolomics and network pharmacology

Background

Aucklandiae Radix (CAR) and its roasted processed products (PAR) are extensively used in various Chinese patent medicines due to their diverse pharmacological activities. However, numerous side effects of CAR have been reported and the hepatotoxicity and the corresponding mechanisms have not been thoroughly investigated. Our study aims to explore the underlying mechanism of the hepatotoxic impacts of CAR.

Methods

In this study, metabolomic analysis was performed using liver tissue from the mice administered with different dosages of CAR/PAR extracts to examine the hepatotoxic impacts of CAR and elucidate the underlying mechanism. Network pharmacology was employed to predict the potential molecular targets and associated signaling pathways based on the distinctive compounds between CAR and PAR. A composition-target-GO-Bio process-metabolic pathway network was constructed by integrating the hepatotoxicity-related metabolic pathways. Finally, the target proteins related with the hepatotoxic effect of CAR were identified and validated in vivo.

Results

The metabolomics analysis revealed that 33 related metabolic pathways were significantly altered in the high-dose CAR group, four of which were associated with the hepatotoxicity and could be alleviated by PAR. The network identified NQO1 as the primary target of the hepatotoxic effect induced by CAR exposure, which was subsequently verified by Western Blotting. Further evidence in vivo demonstrated that Nrf2 and HO-1, closely related to NQO1, were also the main targets through which CAR induced the liver injury, and that oxidative stress should be the primary mechanism for the CAR-induced hepatotoxicity.

Conclusions

This preliminary study on the hepatic toxic injury of CAR provides a theoretical basis for the rational and safe use of CAR rationally and safely in clinical settings.

Stir-fried Semen Armeniacae Amarum Suppresses Aristolochic Acid I-Induced Nephrotoxicity and DNA Adducts

OBJECTIVE

To investigate the protective effects of stir-fried Semen Armeniacae Amarum (SAA) against aristolochic acid I (AAI)-induced nephrotoxicity and DNA adducts and elucidate the underlying mechanism involved for ensuring the safe use of Asari Radix et Rhizoma.

METHODS

In vitro, HEK293T cells overexpressing Flag-tagged multidrug resistance-associated protein 3 (MRP3) were constructed by Lentiviral transduction, and inhibitory effect of top 10 common pairs of medicinal herbs with Asari Radix et Rhizoma in clinic on MRP3 activity was verified using a self-constructed fluorescence screening system. The mRNA, protein expressions, and enzyme activity levels of NAD(P)H quinone dehydrogenase 1 (NQO1) and cytochrome P450 1A2 (CYP1A2) were measured in differentiated HepaRG cells. Hepatocyte toxicity after inhibition of AAI metabolite transport was detected using cell counting kit-8 assay. In vivo, C57BL/6 mice were randomly divided into 5 groups according to a random number table, including: control (1% sodium bicarbonate), AAI (10 mg/kg), stir-fried SAA (1.75 g/kg) and AAI + stir-fried SAA (1.75 and 8.75 g/kg) groups, 6 mice in each group. After 7 days of continuous gavage administration, liver and kidney damages were assessed, and the protein expressions and enzyme activity of liver metabolic enzymes NQO1 and CYP1A2 were determined simultaneously.

RESULTS

In vivo, combination of 1.75 g/kg SAA and 10 mg/kg AAI suppressed AAI-induced nephrotoxicity and reduced dA-ALI formation by 26.7%, and these detoxification effects in a dose-dependent manner (P<0.01). Mechanistically, SAA inhibited MRP3 transport in vitro, downregulated NQO1 expression in vivo, increased CYP1A2 expression and enzymatic activity in vitro and in vivo, respectively (P<0.05 or P<0.01). Notably, SAA also reduced AAI-induced hepatotoxicity throughout the detoxification process, as indicated by a 41.3% reduction in the number of liver adducts (P<0.01).

CONCLUSIONS

Stir-fried SAA is a novel drug candidate for the suppression of AAI-induced liver and kidney damages. The protective mechanism may be closely related to the regulation of transporters and metabolic enzymes.

Histone deacetylase-mediated silencing of PSTPIP2 expression contributes to aristolochic acid nephropathy-induced PANoptosis

BACKGROUND AND PURPOSE

Aristolochic acid nephropathy (AAN) is a progressive kidney disease caused by using herbal medicines. Currently, no therapies are available to treat or prevent aristolochic acid nephropathy. Histone deacetylase (HDAC) plays a crucial role in the development and progression of renal disease. We tested whether HDAC inhibitors could prevent aristolochic acid nephropathy and determined the underlying mechanism.

EXPERIMENTAL APPROACH

HDACs expression in the aristolochic acid nephropathy model was examined. The activation of PANoptosis of mouse kidney and renal tubular epithelial cell were assessed after exposure to HDAC1 and HDAC2 blockade. Kidney-specific knock-in of proline-serine-threonine-phosphatase-interacting protein 2 (PSTPIP2) mice were used to investigate whether PSTPIP2 affected the production of PANoptosome.

KEY RESULTS

Aristolochic acid upregulated the expression of HDAC1 and HDAC2 in the kidneys. Notably, the HDAC1 and HDAC2 specific inhibitor, romidepsin (FK228, depsipeptide), suppressed aristolochic acid-induced kidney injury, epithelial cell pyroptosis, apoptosis and necroptosis (PANoptosis). Moreover, romidepsin upregulated PSTPIP2 in renal tubular epithelial cells, which was enhanced by aristolochic acid treatment. Conditional knock-in of PSTPIP2 in the kidney protected against aristolochic acid nephropathy. In contrast, the knockdown of PSTPIP2 expression in PSTPIP2-knock-in mice restored kidney damage and PANoptosis. PSTPIP2 function was determined in vitro using PSTPIP2 knockdown or overexpression in mouse renal tubular epithelial cells (mTECs). Additionally, PSTPIP2 was found to regulate caspase 8 in aristolochic acid nephropathy.

CONCLUSION AND IMPLICATIONS

HDAC-mediated silencing of PSTPIP2 may contribute to aristolochic acid nephropathy. Hence, HDAC1 and HDAC2 specific inhibitors or PSTPIP2 could be valuable therapeutic agents for preventing aristolochic acid nephropathy.