Acetylshikonin, A Novel CYP2J2 Inhibitor, Induces Apoptosis in RCC Cells via FOXO3 Activation and ROS Elevation

In vivo transgenic studies confirm the critical acylation function of LeBAHD56 for shikonin in Lithospermum erythrorhizon

KEY MESSAGE

LeBAHD56 is preferentially expressed in tissues where shikonin and its derivatives are biosynthesized, and it confers shikonin acylation in vivo. Two WRKY transcriptional factors might regulate LeBAHD56's expression. Shikonin and its derivatives, found in the roots of Lithospermum erythrorhizon, have extensive application in the field of medicine, cosmetics, and other industries. Prior research has demonstrated that LeBAHD1(LeSAT1) is responsible for the biochemical process of shikonin acylation both in vitro and in vivo. However, with the exception of its documented in vitro biochemical function, there is no in vivo genetic evidence supporting the acylation function of the highly homologous gene of LeSAT1, LeBAHD56(LeSAT2), apart from its reported role. Here, we validated the critical acylation function of LeBAHD56 for shikonin using overexpression (OE) and CRISPR/Cas9-based knockout (KO) strategies. The results showed that the OE lines had a significantly higher ratio of acetylshikonin, isobutyrylshikonin or isovalerylshikonin to shikonin than the control. In contrast, the KO lines had a significantly lower ratio of acetylshikonin, isobutyrylshikonin or isovalerylshikonin to shikonin than controls. As for its detailed expression patterns, we found that LeBAHD56 is preferentially expressed in roots and callus cells, which are the biosynthesis sites for shikonin and its derivatives. In addition, we anticipated that a wide range of putative transcription factors might control its transcription and verified the direct binding of two crucial WRKY members to the LeBAHD56 promoter's W-box. Our results not only confirmed the in vivo function of LeBAHD56 in shikonin acylation, but also shed light on its transcriptional regulation.

CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control

Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.

Retracted: Acetylshikonin, A Novel CYP2J2 Inhibitor, Induces Apoptosis in RCC Cells via FOXO3 Activation and ROS Elevation

[This retracts the article DOI: 10.1155/2022/9139338.].

Acetylshikonin induces apoptosis through the endoplasmic reticulum stress-activated PERK/eIF2α /CHOP axis in oesophageal squamous cell carcinoma

Acetylshikonin (AS) is an active component of Lithospermum erythrorhizon Sieb. et Zucc that exhibits activity against various cancers; however, the underlying mechanisms of AS against oesophageal squamous carcinoma (ESCC) need to be elusive. The research explores the anti-cancer role and potential mechanism of AS on ESCC in vitro and in vivo, providing evidences for AS treatment against ESCC. In this study, we firstly demonstrated that AS treatment effectively inhibits cell viability and proliferation of ESCC cells. In addition, AS significantly induces G1/S phage arrest and promotes apoptosis in ESCC cell lines. Further studies reveal that AS induces ER stress, as observed by dose- and time-dependently increased expression of BIP, PDI, PERK, phosphorylation of eIF2α , CHOP and splicing of XBP1. CHOP knockdown or PERK inhibition markedly rescue cell apoptosis induced by AS. Moreover, AS treatment significantly inhibits ESCC xenograft growth in nude mice. Elevated expression of BIP and CHOP is also observed in xenograft tumours. Taken together, AS inhibits proliferation and induces apoptosis through ER stress-activated PERK/eIF2α /CHOP pathway in ESCC, which indicates AS represents a promising candidate for ESCC treatment.

Acetylshikonin induces necroptosis via the RIPK1/RIPK3-dependent pathway in lung cancer

Despite advances in therapeutic strategies, lung cancer remains the leading cause of cancer-related death worldwide. Acetylshikonin is a derivative of the traditional Chinese medicine Zicao and presents a variety of anticancer properties. However, the effects of acetylshikonin on lung cancer have not been fully understood yet. This study explored the mechanisms underlying acetylshikonin-induced cell death in non-small cell lung cancer (NSCLC). Treating NSCLC cells with acetylshikonin significantly reduced cell viability, as evidenced by chromatin condensation and the appearance of cell debris. Acetylshikonin has also been shown to increase cell membrane permeability and induce cell swelling, leading to an increase in the population of necrotic cells. When investigating the mechanisms underlying acetylshikonin-induced cell death, we discovered that acetylshikonin promoted oxidative stress, decreased mitochondrial membrane potential, and promoted G2/M phase arrest in lung cancer cells. The damage to NSCLC cells induced by acetylshikonin resembled results involving alterations in the cell membrane and mitochondrial morphology. Our analysis of oxidative stress revealed that acetylshikonin induced lipid oxidation and down-regulated the expression of glutathione peroxidase 4 (GPX4), which has been associated with necroptosis. We also determined that acetylshikonin induces the phosphorylation of receptor-interacting serine/threonine-protein kinase 1 (RIPK1)/RIPK3 and mixed lineage kinase domain-like kinase (MLKL). Treatment with RIPK1 inhibitors (necrostatin-1 or 7-Cl-O-Nec-1) significantly reversed acetylshikonin-induced MLKL phosphorylation and NSCLC cell death. These results indicate that acetylshikonin activated the RIPK1/RIPK3/MLKL cascade, leading to necroptosis in NSCLC cells. Our findings indicate that acetylshikonin reduces lung cancer cells by promoting G2/M phase arrest and necroptosis.

Temozolomide, Simvastatin and Acetylshikonin Combination Induces Mitochondrial-Dependent Apoptosis in GBM Cells, Which Is Regulated by Autophagy

Glioblastoma multiforme (GBM) is one of the deadliest cancers. Temozolomide (TMZ) is the most common chemotherapy used for GBM patients. Recently, combination chemotherapy strategies have had more effective antitumor effects and focus on slowing down the development of chemotherapy resistance. A combination of TMZ and cholesterol-lowering medications (statins) is currently under investigation in in vivo and clinical trials. In our current investigation, we have used a triple-combination therapy of TMZ, Simvastatin (Simva), and acetylshikonin, and investigated its apoptotic mechanism in GBM cell lines (U87 and U251). We used viability, apoptosis, reactive oxygen species, mitochondrial membrane potential (MMP), caspase-3/-7, acridine orange (AO) and immunoblotting autophagy assays. Our results showed that a TMZ/Simva/ASH combination therapy induced significantly more apoptosis compared to TMZ, Simva, ASH, and TMZ/Simva treatments in GBM cells. Apoptosis via TMZ/Simva/ASH treatment induced mitochondrial damage (increase of ROS, decrease of MMP) and caspase-3/7 activation in both GBM cell lines. Compared to all single treatments and the TMZ/Simva treatment, TMZ/Simva/ASH significantly increased positive acidic vacuole organelles. We further confirmed that the increase of AVOs during the TMZ/Simva/ASH treatment was due to the partial inhibition of autophagy flux (accumulation of LC3β-II and a decrease in p62 degradation) in GBM cells. Our investigation also showed that TMZ/Simva/ASH-induced cell death was depended on autophagy flux, as further inhibition of autophagy flux increased TMZ/Simva/ASH-induced cell death in GBM cells. Finally, our results showed that TMZ/Simva/ASH treatment potentially depends on an increase of Bax expression in GBM cells. Our current investigation might open new avenues for a more effective treatment of GBM, but further investigations are required for a better identification of the mechanisms.

Effects of multi-kinase inhibitors on the activity of cytochrome P450 2J2

1. Cytochrome P450 2J2 (CYP2J2) shows high expression in extrahepatic tissues, including the heart and kidney and in tumours. Inhibition of CYP2J2 has attracted attention for cancer treatment because it metabolises arachidonic acid (AA) to epoxyeicosatrienoic acid (EET), which inhibits apoptosis and promotes tumour growth. Multi-kinase inhibitor (MKI) is a molecular-targeted drug with antitumor activities. This study aimed to clarify the inhibitory effects of MKIs on CYP2J2 activity. We also investigated whether MKIs affected CYP2J2-catalysed EET formation from AA.2. Twenty MKIs showed different inhibitory potencies against astemizole O-demethylation in CYP2J2. In particular, apatinib, motesanib, and vatalanib strongly inhibited astemizole O-demethylation. These three MKIs exhibited competitive inhibition with inhibition constant (K_i) values of 9.3, 15.4, and 65.0 nM, respectively. Apatinib, motesanib, and vatalanib also inhibited CYP2J2-catalysed 14,15-EET formation from AA.3. In simulations of docking to CYP2J2, the U energy values of apatinib, motesanib, and vatalanib were low, and measured -84.5, -69.9, and -52.3 kcal/mol, respectively.4. In conclusion, apatinib, motesanib, and vatalanib strongly inhibited CYP2J2 activity, suggesting that the effects of a given CYP2J2 substrate may be altered upon the administration of these MKIs.