Gambogenic acid alleviates kidney fibrosis via epigenetic inhibition of EZH2 to regulate Smad7-dependent mechanism

Unveiling Gambogenic Acid as a Promising Antitumor Compound: A Review

Gambogenic acid is a derivative of gambogic acid, a polyprenylated xanthone isolated from Garcinia hanburyi. Compared with the more widely studied gambogic acid, gambogenic acid has demonstrated advantages such as a more potent antitumor effect and less systemic toxicity than gambogic acid according to early investigations. Therefore, the present review summarizes the effectiveness and mechanisms of gambogenic acid in different cancers and highlights the mechanisms of action. In addition, drug delivery systems to improve the bioavailability of gambogenic acid and its pharmacokinetic profile are included. Gambogenic acid has been applied to treat a wide range of cancers, such as lung, liver, colorectal, breast, gastric, bladder, and prostate cancers. Gambogenic acid exerts its antitumor effects as a novel class of enhancer of zeste homolog 2 inhibitors. It prevents cancer cell proliferation by inducing apoptosis, ferroptosis, and necroptosis and controlling the cell cycle as well as autophagy. Gambogenic acid also hinders tumor cell invasion and metastasis by downregulating metastasis-related proteins. Moreover, gambogenic acid increases the sensitivity of cancer cells to chemotherapy and has shown effects on multidrug resistance in malignancy. This review adds insights for the prevention and treatment of cancers using gambogenic acid.

Caged xanthone derivatives to promote mitochondria-mediated apoptosis in breast cancer cells

Caged xanthones represent a class of natural secondary metabolites exhibiting significant potential as antitumor agents. These compounds are characterized by their distinct cage-like structures, which offer novel and compelling frameworks for drug design. Nonetheless, there exists a dearth of research focused on the structural modification of these compounds, particularly in relation to their cage-like architectures. This study aims to address this gap by introducing an innovative synthetic method for constructing a novel caged structure that incorporates a widely employed maleimide group. Drawing upon the well-established synthetic approach for dihydroxanthones previously developed within our research group, we successfully synthesized 13 new caged xanthones using the Diels-Alder reaction. Subsequently, we evaluated their anti-proliferative activity against HepG2, A549, and MDA-MB-231 cell lines. The results revealed that compound 10i exhibited IC50 values of 15.86 µM ± 1.29, 19.27 µM ± 1.58, and 12.96 µM ± 0.09 against these cell lines, respectively. Further investigations into the mechanism of action of 10i demonstrated its ability to induce G2/M cell cycle arrest and initiate mitochondria-mediated apoptosis in breast cancer cells.

Design, synthesis, and biological evaluation of gambogenic acid derivatives: Unraveling their anti-cancer effects by inducing pyroptosis

Gambogenic acid (GNA), a caged xanthone derived from Garcinia hanburyi, exhibits a wide range of anti-cancer properties. The caged skeleton of GNA serves as the fundamental pharmacophore responsible for its antitumor effects. However, limited exploration has focused on the structural modifications of GNA. This study endeavors to diversify the structure of GNA and enhance its anti-cancer efficacy. Sulfoximines, recognized as pivotal motifs in medicinal chemistry due to their outstanding properties, have featured in several anti-cancer drugs undergoing clinical trials. Accordingly, a series of 33 GNA derivatives combined with sulfoximines were synthesized and evaluated for their anti-cancer effects against MIAPaCa2, MDA-MB-231, and A549 cells in vitro. The activity screening led to the identification of compound 12k, which exhibited the most potent anti-cancer effect. Mechanistic studies revealed that 12k primarily induced pyroptosis in MIAPaCa2 and MDA-MB-231 cells by activating the caspase-3/gasdermin E (GSDME) pathway. These findings suggested that 12k is a promising drug candidate in cancer therapy and highlighted the potential of sulfoximines as a valuable functional group in drug discovery.

Novel therapeutic approaches in the management of chronic kidney disease: a narrative review

Chronic kidney disease (CKD) remains a pathologic entity with constantly rising incidence and high rates of morbidity and mortality, which are associated with serious cardiovascular complications. Moreover, the incidence of end-stage renal disease tends to increase. The epidemiological trends of CKD warrant the development of novel therapeutic approaches aiming to prevent its development or retard its progression through the control of major risk factors: type 2 diabetes mellitus, arterial hypertension, and dyslipidemia. Contemporary therapeutics such as sodium-glucose cotransporter-2 inhibitors and second-generation mineralocorticoid receptor antagonists are utilized in this direction. Additionally, experimental and clinical studies present novel drug categories that could be employed in managing CKD, such as aldosterone synthesis inhibitors or activators guanylate cyclase, while the role of melatonin should be further tested in the clinical setting. Finally, in this patient population, the use of hypolipidemic agents may provide incremental benefits.

Novel aspect of neprilysin in kidney fibrosis via ACSL4-mediated ferroptosis of tubular epithelial cells

Although inhibition of neprilysin (NEP) might be a therapeutic strategy with the potential to improve the outcome of chronic kidney disease (CKD), the versatile function of NEP with its mechanism remains obscure in kidney fibrosis. In the study, we found that NEP was abnormally increased in tubular epithelial cells of CKD patients, as well as unilateral ureteral obstruction and adenine diet-induced mice. Treatment with a United States Food and Drug Administration-approved NEP inhibitor Sacubitrilat (LBQ657) could alleviate ferroptosis, tubular injury, and delay the progression of kidney fibrosis in experimental mice. Similarly, genetic knockdown of NEP also inhibited tubular injury and fibrosis in transforming growth factor (TGF)-β1 -induced tubular cells. Mechanically, NEP overexpression aggravated the ferroptotic and fibrotic phenotype, which was restored by acyl-CoA synthetase long-chain family member 4 (ACSL4) knockdown. The NEP silencing attenuated TGF-β1-induced tubular cell ferroptosis and was exacerbated by ACSL4 overexpression. Collectively, for the first time, a novel aspect of NEP was explored in kidney fibrosis through ACSL4-mediated tubular epithelial cell ferroptosis. Our data further confirmed that NEP inhibition exerted a promising therapeutic against fibrotic kidney diseases.

EZH2 serves as a promising therapeutic target for fibrosis

Fibrosis affects the function of many organs and tissues, and its persistent development can lead to tissue sclerosis and cancer, even leading to death further. Recent studies suggested that enhancer of zeste homolog 2 (EZH2), a major regulator of epigenetic repression, played an important role in the occurrence and development of fibrosis through gene silencing or transcriptional activation. As the most studied and powerful pro-fibrotic cytokine closely related to EZH2, TGF-β1 was primarily involved in the regulation of fibrosis along with the typical Smads and non-Smads signaling pathways. In addition, EZH2 inhibitors demonstrated inhibitory effects in several types of fibrosis. This review summarized the relationship underlying the action of EZH2, TGF-β1/Smads, and TGF-β1/non-Smads with fibrosis and described the research progress of EZH2 inhibitors in the treatment of fibrosis.

Kidney fibrosis: from mechanisms to therapeutic medicines

Chronic kidney disease (CKD) is estimated to affect 10-14% of global population. Kidney fibrosis, characterized by excessive extracellular matrix deposition leading to scarring, is a hallmark manifestation in different progressive CKD; However, at present no antifibrotic therapies against CKD exist. Kidney fibrosis is identified by tubule atrophy, interstitial chronic inflammation and fibrogenesis, glomerulosclerosis, and vascular rarefaction. Fibrotic niche, where organ fibrosis initiates, is a complex interplay between injured parenchyma (like tubular cells) and multiple non-parenchymal cell lineages (immune and mesenchymal cells) located spatially within scarring areas. Although the mechanisms of kidney fibrosis are complicated due to the kinds of cells involved, with the help of single-cell technology, many key questions have been explored, such as what kind of renal tubules are profibrotic, where myofibroblasts originate, which immune cells are involved, and how cells communicate with each other. In addition, genetics and epigenetics are deeper mechanisms that regulate kidney fibrosis. And the reversible nature of epigenetic changes including DNA methylation, RNA interference, and chromatin remodeling, gives an opportunity to stop or reverse kidney fibrosis by therapeutic strategies. More marketed (e.g., RAS blockage, SGLT2 inhibitors) have been developed to delay CKD progression in recent years. Furthermore, a better understanding of renal fibrosis is also favored to discover biomarkers of fibrotic injury. In the review, we update recent advances in the mechanism of renal fibrosis and summarize novel biomarkers and antifibrotic treatment for CKD.

Tubular aryl hydratocarbon receptor upregulates EZH2 to promote cellular senescence in cisplatin-induced acute kidney injury

Acute kidney injury (AKI) is one of the serious clinical syndromes with high morbidity and mortality. Despite substantial progress in understanding the mechanism of AKI, no effective drug is available for treatment or prevention. In this study, we identified that a ligand-activated transcription factor aryl hydrocarbon receptor (AhR) was abnormally increased in the kidneys of cisplatin-induced AKI mice or tubular epithelial TCMK-1 cells. The AhR inhibition by BAY2416964 and tubular conditional deletion both alleviated cisplatin-induced kidney dysfunction and tubular injury. Notably, inhibition of AhR could improve cellular senescence of injured kidneys, which was indicated by senescence-associated β-galactosidase (SA-β-gal) activity, biomarker p53, p21, p16 expression, and secretory-associated secretory phenotype IL-1β, IL-6 and TNFα level. Mechanistically, the abnormal AhR expression was positively correlated with the increase of a methyltransferase EZH2, and AhR inhibition suppressed the EZH2 expression in cisplatin-injured kidneys. Furthermore, the result of ChIP assay displayed that EZH2 might indirectly interact with AhR promoter region by affecting H3K27me3. The direct recruitment between H3K27me3 and AhR promoter is higher in the kidneys of control than that of cisplatin-treated mice, suggesting EZH2 reversely influenced AhR expression through weakening H3K27me3 transcriptional inhibition on AhR promoter. The present study implicated that AhR and EZH2 have mutual regulation, which further accelerated tubular senescence in cisplatin-induced AKI. Notably, the crucial role of AhR is potential to become a promising target for AKI.