Underlying mechanisms and management strategies for regorafenib-induced toxicity in hepatocellular carcinoma.

INTRODUCTION: Hepatocellular carcinoma (HCC) accounts for 85% of liver cancer cases and is the third leading cause of cancer death. Regorafenib is a multi-target inhibitor that dramatically prolongs progression-free survival in HCC patients who have failed sorafenib therapy. However, one of the primary factors limiting regorafenib's clinical utilization is toxicity. Using Clinical Trials.gov and PubMed, we gathered clinical data on regorafenib and conducted a extensive analysis of the medication's adverse reactions and mechanisms. Next, we suggested suitable management techniques to improve regorafenib's effectiveness. AREAS COVERED: We have reviewed the mechanisms by which regorafenib-induced toxicity occurs and general management strategies through clinical trials of regorafenib. Furthermore, by examining the literature on regorafenib and other tyrosine kinase inhibition, we summarized the mechanics of the onset of regorafenib toxicity and mechanism-based intervention strategies by reviewing the literature related to regorafenib and other tyrosine kinase inhibition. EXPERT OPINION: One of the primary factors restricting regorafenib's clinical utilization and combination therapy is its toxicity reactions. To optimize regorafenib treatment regimens, it is especially important to further understand the specific toxicity mechanisms of regorafenib as a multi-kinase inhibitor.

Schisandrin C prevents Regorafenib-Induced cardiotoxicity by recovering EPHA2 expression in cardiomyocytes.

Regorafenib, an oral multikinase inhibitor of angiogenic, stromal, and oncogenic receptor tyrosine kinases, has been approved for the treatment of metastatic colorectal cancer, gastrointestinal stromal tumors and hepatocellular carcinoma by the US Food and Drug Administration and European Medicines Agency. However, regorafenib-induced cardiotoxicity increases the risk of mortality. Despite reports that regorafenib can cause mitochondrial dysfunction in cardiomyocytes, the molecular mechanism of regorafenib-induced cardiotoxicity is much less known and there is an urgent need for intervention strategies. Here, we treated mice with vehicle or 200 mg/kg regorafenib daily for 42 days by gavage or treated cardiomyocyte lines with 8, 16 or 32 µM regorafenib, and we found that regorafenib could cause apoptosis, mitochondrial injury and DNA damage in cardiomyocytes. Mechanistically, regorafenib can reduce the expression of EPHA2, which inhibits AKT signaling, leading to cardiomyocyte apoptosis and cardiotoxicity. In addition, we showed that recovering EPHA2 expression via plasmid-induced overexpression of EPHA2 or schisandrin C, a natural product, could prevent regorafenib-induced cardiotoxicity. These findings demonstrated that regorafenib causes cardiomyocyte apoptosis and cardiac injury by reducing the expression of EPHA2 and schisandrin C could prevent regorafenib-induced cardiotoxicity by recovering EPHA2 expression, which provides a potential management strategy for regorafenib-induced cardiotoxicity and will benefit the safe application of regorafenib in clinic.

Palmitoyltransferase ZDHHC3 is essential for the oncogenic activity of PML/RARα in acute promyelocytic leukemia.

The oncogenic fusion protein promyelocytic leukemia/retinoic acid receptor alpha (PML/RARα) is critical for acute promyelocytic leukemia (APL). PML/RARα initiates APL by blocking the differentiation and increasing the self-renewal of leukemic cells. The standard clinical therapies all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), which induce PML/RARα proteolysis, have dramatically improved the prognosis of APL patients. However, the emergence of mutations conferring resistance to ATRA and ATO has created challenges in the treatment of APL patients. Exploring pathways that modulate the oncogenic activity of PML/RARα could help develop novel therapeutic strategies for APL, particularly for drug-resistant APL. Herein, we demonstrated for the first time that palmitoylation of PML/RARα was a critical determinant of its oncogenic activity. PML/RARα palmitoylation was found to be catalyzed mainly by the palmitoyltransferase ZDHHC3. Mechanistically, ZDHHC3-mediated palmitoylation regulated the oncogenic transcriptional activity of PML/RARα and APL pathogenesis. The knockdown or overexpression of ZDHHC3 had respective effects on the expression of proliferation- and differentiation-related genes. Consistently, the depletion or inhibition of ZDHHC3 could significantly arrest the malignant progression of APL, particularly drug-resistant APL, whereas ZDHHC3 overexpression appeared to have a promoting effect on the malignant progression of APL. Thus, our study not only reveals palmitoylation as a novel regulatory mechanism that modulates PML/RARα oncogenic activity but also identifies ZDHHC3 as a potential therapeutic target for APL, including drug-resistant APL.

Zosuquidar Promotes Antitumor Immunity by Inducing Autophagic Degradation of PD-L1.

The intracellular distribution and transportation process are essential for maintaining PD-L1 (programmed death-ligand 1) expression, and intervening in this cellular process may provide promising therapeutic strategies. Here, through a cell-based high content screening, it is found that the ABCB1 (ATP binding cassette subfamily B member 1) modulator zosuquidar dramatically suppresses PD-L1 expression by triggering its autophagic degradation. Mechanistically, ABCB1 interacts with PD-L1 and impairs COP II-mediated PD-L1 transport from ER (endoplasmic reticulum) to Golgi apparatus. The treatment of zosuquidar enhances ABCB1-PD-L1 interaction and leads the ER retention of PD-L1, which is subsequently degraded in the SQSTM1-dependent selective autophagy pathway. In CT26 mouse model and a humanized xenograft mouse model, zosuquidar significantly suppresses tumor growth and accompanies by increased infiltration of cytotoxic T cells. In summary, this study indicates that ABCB1 serves as a negative regulator of PD-L1, and zosuquidar may act as a potential immunotherapy agent by triggering PD-L1 degradation in the early secretory pathway.

Preserving mitochondrial homeostasis protects against drug-induced liver injury via inducing OPTN (optineurin)-dependent Mitophagy.

Disruption of mitochondrial function is observed in multiple drug-induced liver injuries (DILIs), a significant global health threat. However, how the mitochondrial dysfunction occurs and whether maintain mitochondrial homeostasis is beneficial for DILIs remains unclear. Here, we show that defective mitophagy by OPTN (optineurin) ablation causes disrupted mitochondrial homeostasis and aggravates hepatocytes necrosis in DILIs, while OPTN overexpression protects against DILI depending on its mitophagic function. Notably, mass spectrometry analysis identifies a new mitochondrial substrate, GCDH (glutaryl-CoA dehydrogenase), which can be selectively recruited by OPTN for mitophagic degradation, and a new cofactor, VCP (valosin containing protein) that interacts with OPTN to stabilize BECN1 during phagophore assembly, thus boosting OPTN-mediated mitophagy initiation to clear damaged mitochondria and preserve mitochondrial homeostasis in DILIs. Then, the accumulation of OPTN in different DILIs is further validated with a protective effect, and pyridoxine is screened and established to alleviate DILIs by inducing OPTN-mediated mitophagy. Collectively, our findings uncover a dual role of OPTN in mitophagy initiation and implicate the preservation of mitochondrial homeostasis via inducing OPTN-mediated mitophagy as a potential therapeutic approach for DILIs.Abbreviation: AILI: acetaminophen-induced liver injury; ALS: amyotrophic lateral sclerosis; APAP: acetaminophen; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CHX: cycloheximide; Co-IP: co-immunoprecipitation; DILI: drug-induced liver injury; FL: full length; GCDH: glutaryl-CoA dehydrogenase; GOT1/AST: glutamic-oxaloacetic transaminase 1; GO: gene ontology; GSEA: gene set enrichment analysis; GPT/ALT: glutamic - pyruvic transaminase; INH: isoniazid; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MMP: mitochondrial membrane potential; MST: microscale thermophoresis; MT-CO2/COX-II: mitochondrially encoded cytochrome c oxidase II; OPTN: optineurin; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; TIMM23: translocase of inner mitochondrial membrane 23; TOMM20: translocase of outer mitochondrial membrane 20; TSN: toosendanin; VCP: valosin containing protein, WIPI2: WD repeat domain, phosphoinositide interacting 2.

Targeting the Wnt/ß-catenin signal pathway for the treatment of gastrointestinal cancer: Potential for advancement.

Gastrointestinal cancers (GICs) are highly prevalent cancers that threaten human health worldwide. The Wnt/ß-catenin signaling pathway has been reported to play a pivotal role in the carcinogenesis of GICs. Numerous interventions targeting the Wnt/ß-catenin signaling in GICs are currently being tested in clinical trials with promising results. Unfortunately, there are no clinically approved drugs that effectively target this pathway. This comprehensive review aims to evaluate the impact of clinical therapies targeting the Wnt/ß-catenin signaling pathway in GICs. By integrating data from bioinformatics databases and recent literature from the past five years, we examine the heterogeneous expression and regulatory mechanisms of Wnt/ß-catenin pathway genes and proteins in GICs. Specifically, we focus on expression patterns, mutation frequencies, and clinical prognoses to understand their implications for treatment strategies. Additionally, we discuss recent clinical trial efforts targeting this pathway. Understanding the inhibitors currently under clinical investigation may help optimize foundational research and clinical strategies. We hope that elucidating the current status of precision therapeutic stratification for patients targeting the Wnt/ß-catenin pathway will guide future innovations in precision medicine for GICs.

PROTAC-Mediated HDAC7 Protein Degradation Unveils Its Deacetylase-Independent Proinflammatory Function in Macrophages.

Class IIa histone deacetylases (Class IIa HDACs) play critical roles in regulating essential cellular metabolism and inflammatory pathways. However, dissecting the specific roles of each class IIa HDAC isoform is hindered by the pan-inhibitory effect of current inhibitors and a lack of tools to probe their functions beyond epigenetic regulation. In this study, a novel PROTAC-based compound B4 is developed, which selectively targets and degrades HDAC7, resulting in the effective attenuation of a specific set of proinflammatory cytokines in both lipopolysaccharide (LPS)-stimulated macrophages and a mouse model. By employing B4 as a molecular probe, evidence is found for a previously explored role of HDAC7 that surpasses its deacetylase function, suggesting broader implications in inflammatory processes. Mechanistic investigations reveal the critical involvement of HDAC7 in the Toll-like receptor 4 (TLR4) signaling pathway by directly interacting with the TNF receptor-associated factor 6 and TGFß-activated kinase 1 (TRAF6-TAK1) complex, thereby initiating the activation of the downstream mitogen-activated protein kinase/nuclear factor-κB (MAPK/NF-κB) signaling cascade and subsequent gene transcription. This study expands the insight into HDAC7's role within intricate inflammatory networks and highlights its therapeutic potential as a novel target for anti-inflammatory treatments.

Unraveling the treatment effects of huanglian jiedu decoction on drug-induced liver injury based on network pharmacology, molecular docking and experimental validation.

Huanglian Jiedu Decoction (HJD) is a well-known Traditional Chinese Medicine formula that has been used for liver protection in thousands of years. However, the therapeutic effects and mechanisms of HJD in treating drug-induced liver injury (DILI) remain unknown. In this study, a total of 26 genes related to both HJD and DILI were identified, which are corresponding to a total of 41 potential active compounds in HJD. KEGG analysis revealed that Tryptophan metabolism pathway is particularly important. The overlapped genes from KEGG and GO analysis indicated the significance of CYP1A1, CYP1A2, and CYP1B1. Experimental results confirmed that HJD has a protective effect on DILI through Tryptophan metabolism pathway. In addition, the active ingredients Corymbosin, and Moslosooflavone were found to have relative strong intensity in UPLC-Q-TOF-MS/MS analysis, showing interactions with CYP1A1, CYP1A2, and CYP1B1 through molecule docking. These findings could provide insights into the treatment effects of HJD on DILI.

The Combination of Gefitinib and Acetaminophen Exacerbates Hepatotoxicity via ROS-Mediated Apoptosis.

Gefitinib is the well-tolerated first-line treatment of non-small cell lung cancer. As it need for analgesics during oncology treatment, particularly in the context ofthe coronavirus disease, where patients are more susceptible to contract high fever and sore throat. This has increased the likelihood of taking both gefitinib and antipyretic analgesic acetaminophen (APAP). Given that gefitinib and APAP overdose can predispose patients to liver injury or even acute liver failure, there is a risk of severe hepatotoxicity when these two drugs are used concomitantly. However, little is known regarding their safety at therapeutic doses. This study simulated the administration of gefitinib and APAP at clinically relevant doses in an animal model and confirmed that gefitinib in combination with APAP exhibited additional hepatotoxicity. We found that gefitinib plus APAP significantly exacerbated cell death, whereas each drug by itself had little or minor effect on hepatocyte survival. Mechanistically, combination of gefitinib and APAP induces hepatocyte death via the apoptotic pathway obviously. Reactive oxygen species (ROS) generation and DNA damage accumulation are involved in hepatocyte apoptosis. Gefitinib plus APAP also promotes the expression of Kelch-like ECH-associated protein 1 (Keap1) and downregulated the antioxidant factor, Nuclear factor erythroid 2-related factor 2 (Nrf2), by inhibiting p62 expression. Taken together, this study revealed the potential ROS-mediated apoptosis-dependent hepatotoxicity effect of the combination of gefitinib and APAP, in which the p62/Keap1/Nrf2 signaling pathway participates and plays an important regulatory role.