Jolkinolide B synergistically potentiates the antitumor activity of GPX4 inhibitors via inhibiting TrxR1 in cisplatin-resistant bladder cancer cells

Glutathione peroxidase 4 (GPX4) is a promising anticancer therapeutic target; however, the application of GPX4 inhibitors (GPX4i) is limited owing to intrinsic or acquired drug resistance. Hence, understanding the mechanisms underlying drug resistance and discovering molecules that can overcome drug resistance are crucial. Herein, we demonstrated that GPX4i killed bladder cancer cells by inducing lipid reactive oxygen species-mediated ferroptosis and apoptosis, and cisplatin-resistant bladder cancer cells were also resistant to GPX4i, representing a higher half-maximal inhibitory concentration value than that of parent bladder cancer cells. In addition, thioredoxin reductase 1 (TrxR1) overexpression was responsible for GPX4i resistance in cisplatin-resistant bladder cancer cells, and inhibiting TrxR1 restored the sensitivity of these cells to GPX4i. In vitro and in vivo studies revealed that Jolkinolide B (JB), a natural diterpenoid and previously identified as a TrxR1 inhibitor, potentiated the antiproliferative efficacy of GPX4i (RSL3 and ML162) against cisplatin-resistant bladder cancer cells. Furthermore, GPX4 knockdown and inhibition could augment JB-induced paraptosis and apoptosis. Our results suggest that inhibiting TrxR1 can effectively improve GPX4 inhibition-based anticancer therapy. A combination of JB and GPX4i, which is well-tolerated and has several anticancer mechanisms, may serve as a promising therapy for treating bladder cancer.

Jolkinolide B ameliorates rheumatoid arthritis by regulating the JAK2/STAT3 signaling pathway

BACKGROUND

Jolkinolide B (JB), an ent‑abietane-type diterpenoid in Euphorbia plants, has various pharmacological activities, including anticancer, anti-inflammatory, and anti-tuberculosis activities. However, no previous studies have proven whether JB can be regarded as a targeted drug for the treatment of rheumatoid arthritis (RA).

PURPOSE

This study aimed to evaluate the anti-RA effects of JB and explore the potential mechanisms.

METHODS

Components and targets of JB and RA were identified in different databases, and potential targets and pathways were predicted by protein-protein interaction (PPI) network analysis and pathway enrichment analysis. Then, molecular docking and surface-plasmon resonance (SPR) were used to confirm the predict. The anti-arthritic effects of JB were studied in vivo with collagen-induced arthritis (CIA) rat model and in vitro with lipopolysaccharide (LPS) and interleukin-6 (IL-6)-induced RAW264.7 macrophage. Potential mechanisms were further verified by in vivo and in vitro experiments.

RESULTS

The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that Th17 cell differentiation, prolactin signaling pathway, and JAK/STAT signaling pathway might be associated with anti-RA effects of JB. Molecular docking and SPR results showed that JB bound effectively to JAK2. JB significantly decreased body weight loss, arthritis index, paw thickness, and synovial thickness in CIA rats. Histomorphological results suggested the protective effects of JB on CIA rats with ankle joint injury. Molecular biology analysis indicated that JB suppressed the mRNA expression of inflammatory factors in ankle joints for CIA rats and reduced the concentration of these factors in LPS- induced RAW264.7 macrophage. The protein expression level of the JAK2/STAT3 pathway was also significantly decreased by JB.

CONCLUSION

JB had a novel inhibitory effect on inflammation and bone destruction in CIA rats, and the mechanism might be related to the JAK2/STAT3 signaling pathway.

Jolkinolide B: A comprehensive review of its physicochemical properties, analytical methods, synthesis and pharmacological activity

Jolkinolide B is a typical ent-abietane-type diterpenoid, which is first found in Euphorbia jolkini. It is one of the most important active components in many toxic Euphorbia plants. In recent years, jolkinolide B has garnered increasing attention due to its high potent and multiple pharmacological activities. In order to better understand the research status of jolkinolide B, relevant information about jolkinolide B was collected from scientific databases (SciFinder Scholar, PubMed, ACS website, Elsevier, Web of Science, Google Scholar, Science Direct, and CNKI). There are few studies on chemical synthesis and biosynthesis of jolkinolide B. In addition, researchers on the activities of jolkinolide B are mostly concentrated at the cellular level, and there is a lack of research on the mechanism. In this review, the possible applications of jolkinolide B were systematically illustrated for the first time, from plant sources, physicochemical properties, analytical methods, synthesis and pharmacological activities. Jolkinolide B exhibits extensive pharmacological properties, including anticancer, anti-inflammatory, anti-osteoporosis, and anti-tuberculosis activities. Pharmacological activities of jolkinolide B were mainly focused on anticancer and anti-inflammatory activities, and the mechanism of action may be related with inhibition of JAK/STAT pathway, NF-κB pathway and PI3K/Akt/mTOR pathway. In addition, the extraction methods and analytical methods discussed in this review, will facilitate the development of novel herbal products for better healthcare solutions.

Jolkinolide B induces cell cycle arrest and apoptosis in MKN45 gastric cancer cells and inhibits xenograft tumor growth in vivo

Gastric cancer is one of the most common digestive carcinomas throughout the world and represents high mortality. There is an urgent quest for seeking a novel and efficient antigastric cancer drug. Euphorbia fischeriana Steud had long been used as a traditional Chinese medicine for the treatment of cancer. According to the basic theory of traditional Chinese medicine, its antitumor mechanism is ‘to combat poison with poison’. However, its effective material foundation of it is still ambiguous. In our previous work, we studied the chemical constituents of E. fischeriana Steud. Jolkinolide B (JB) is an ent-abietane-type diterpenoid we isolated from it. The purpose of the present study was to investigate the antigastric effect and mechanism of JB. Results revealed that JB could suppress the proliferation of MKN45 cells in vitro and inhibit MKN45 xenograft tumor growth in nude mice in vivo. We further investigated its anticancer mechanism. On the one hand, JB caused DNA damage in gastric cancer MKN45 cells and induced the S cycle arrest by activating the ATR-CHK1-CDC25A-Cdk2 signaling pathway, On the other hand, JB induced MKN45 cells apoptosis through the mitochondrial pathway, and ultimately effectively inhibited the growth of gastric cancer cells. These results suggest that JB appears to be a promising candidate drug with antigastric cancer activity and warrants further research.

Jolkinolide B inhibits proliferation or migration and promotes apoptosis of MCF-7 or BT-474 breast cancer cells by downregulating the PI3K-Akt pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The diterpenoids extracted from Euphorbia kansui S.L. Liou ex S.B.Ho, Euphorbia fischeriana Steud. have good antitumor effects. Jolkinolide B has anti-breast cancer effect, but it is unclear whether it has different therapeutic effects between luminal A subtype and luminal B subtype breast cancer.

AIM OF THE STUDY

This study investigated the Jolkinolide B has different therapeutic, important targets and pathways effects between luminal A subtype and luminal B subtype breast cancer.

MATERIALS AND METHODS

We used bioinformatics to predict the biological process and molecular mechanism of Jolkinolide B in treating two types of breast cancer. Then, in vitro, cultured MCF-7 cells and BT-474 cells were divided into control group, PI3K inhibitor + control group, Jolkinolide B group and PI3K inhibitor + Jolkinolide B group. The CCK-8 assay, Flow cytometric analysis and Transwell cell migration assay was used to detect the cell proliferation, apoptosis, and migration in each group, respectively. ELISA was used to measure the content of Akt and phosphorylated Akt (p-Akt) in cell lysis buffer.

RESULTS

Compared to luminal A breast cancer, Jolkinolide B had more targets, proliferation, migration processes and KEGG pathways when treating luminal B subtype breast cancer. Jolkinolide B significantly prolonged the survival time of luminal B subtype breast cancer patients. Compared to the control group, the cell proliferation absorbance value (A value) and migration number of the two kinds of breast cancer cells in the Jolkinolide B group were decreased (P < 0.01, n = 6), and the number of apoptotic cells was increased (P < 0.01, n = 6). Compared to the Jolkinolide B group, the A value and migration number of the two types of breast cancer cells were significantly decreased in the PI3K inhibitor + Jolkinolide B group (P < 0.01, n = 6), and the number of apoptotic cells was significantly increased (P < 0.01, n = 6). In addition, compared to MCF-7 cells, the A value and migration number of BT-474 cells stimulated with Jolkinolide B were significantly decreased (P < 0.01, n = 6), and the number of apoptotic cells was significantly increased (P < 0.01, n = 6). Akt and p-Akt protein levels in the two breast cancer cell lines in the Jolkinolide B group were all decreased (P < 0.01, n = 6), especially in BT-474 cells stimulated by Jolkinolide B.

CONCLUSION

Jolkinolide B regulates the luminal A and luminal B subtypes of breast cancer through PI3K-Akt, EGFR and other pathways. Jolkinolide B has more significant therapeutic effect on luminal B subtype breast cancer. In vitro, experiments verified that Jolkinolide B significantly inhibited the proliferation and migration activity of BT-474 breast cancer cells by downregulating the PI3K-Akt pathway.

Jolkinolide B alleviates renal fibrosis via anti-inflammation and inhibition of epithelial-mesenchymal transition in unilateral ureteral obstruction mice

Renal fibrosis is a critical pathological process lead to a progressive loss of renal function. Jolkinolide B (JB) is a natural compound with anti-inflammatory activity from Euphorbia fischeriana Steud. The study evaluated the effect of JB on renal fibrosis in mice with unilateral ureteral obstruction (UUO). The results showed that JB could decrease renal fibrotic area, reduce phosphorylation of NF-κB p65 and the release of TNF-α, IL-6 and IL-1β, restore the expression of vementin, α-SMA and E-cadherin, as well as TGF-β1 and p-smad2/3. In conclusion, JB might reduce renal fibrosis by inhibiting inflammation induced by NF-κB pathway and EMT mediated by TGF-β1/Smad pathway.

Jolkinolide B attenuates laryngeal cancer cell growth and induces apoptosis via PTEN/PI3K/Akt signaling pathway

Jolkinolide B (JB) is a bioactive diterpenoid, isolated from the root of Euphorbia fischeriana Steud, and has been reported to have anti-tumor and anti-inflammation function by regulation of cell migration, invasion, apoptosis, and cell cycle. We aimed to evaluate the effect of JB on laryngeal cancer cells. Human normal larynx epithelial (HBE) cells and cancer cell lines TU212, TU177, and Hep-2 were cultured; MTT assay was used to assess cell proliferation. LY294002 (a PI3K/Akt inhibitor) and IGF-1 (a PI3K/Akt activator) were employed to investigate the expression of PI3K/Akt pathway. Cell migration and invasion activities were detected by scratch wound healing and transwell assay, respectively. Flow cytometry assay was used to assess cell apoptosis. The expression levels of proteins were assessed by immunofluorescence and Western blotting assay. JB inhibited TU212, TU177, and Hep-2 cell viability with an IC₅₀ value of 54.57 ± 0.53 μg/mL, 44.82 ± 0.32 μg/mL, and 49.63 ± 0.47 μg/mL, respectively. Compared with control group, the proliferation, migration, and invasion of cells significantly decreased after JB and LY294002 treatment, while cell apoptosis increased. In IGF-1 group, the results were opposite compared to the JB and LY294002 groups. Western blotting results showed that JB and LY294002 treatment significantly inhibited the levels of Bcl-2, p-PI3K, and p-Akt while the levels of Bax, cleaved caspase-3, and PTEN protein significantly increased. Our study suggested that JB exhibits an inhibition effect on laryngeal cancer cell growth in vitro.

A Nano-Traditional Chinese Medicine Against Lymphoma That Regulates the Level of Reactive Oxygen Species

Jolkinolide B (JB) is a bioactive compound isolated from a Chinese herbal medicine that exerts antitumor activity. However, the anti-lymphoma effect of JB and its mechanism are yet to be revealed. Because free JB has poor pharmacokinetics and weak antitumor efficacy, we opted to use black phosphorus quantum dot (BPQD) nanomaterials as a drug loading platform to synthesize a nano-traditional Chinese medicine (nano-TCM) called BPQDs@JB. Compared with free JB, Raji cells administrated with BPQDs@JB exhibited the cell viability of 19.85 ± 1.02%, and the production of intracellular reactive oxygen species (ROS) was promoted. Likewise, BPQDs@JB was capable of rising the apoptosis rate of Raji cells to 34.98 ± 1.76%. In nude mice transplanted tumor model administrated with BPQDs@JB, the tumor tissue sections administrated with BPQDS@JB achieved a conspicuous red fluorescence, demonstrating the presence of most ROS production in the BPQDS@JB. TUNEL achieved a number of positive (brown) nuclei in vivo, revealing that BPQDS@JB could significantly induce tumor tissue apoptosis. As revealed from the mentioned results, BPQDs@JB can generate considerable ROS and interfere with the redox state to inhibit tumor. In brief, BPQDs@JB may be adopted as a treatment option for lymphoma.

Protective effect of Jolkinolide B on LPS-induced mouse acute lung injury

Jolkinolide B (JB), an ent-abietane diterpenoid, isolated from the dried root of Euphorbia fischeriana, has been reported to have potent anti-tumor and anti-inflammatory activities. However, the effects of JB on acute lung injury (ALI) and underlying molecular mechanisms have not been investigated. The present study aimed to investigate the effect of JB on lipopolysaccharide (LPS)-induced ALI. Male C57BL/6 mice were pretreated with dexamethasone or JB 1h before intranasal instillation of LPS. The results showed that JB markedly attenuated LPS-induced histological alterations, lung edema, inflammatory cell infiltration, myeloperoxidase (MPO) activity as well as the production of TNF-α, IL-6 and IL-1β. Furthermore, JB also significantly inhibited LPS-induced the degradation of IκBα and phosphorylation of NF-κB p65 and MAPK. Therefore, our study provides the first line of evidence that pretreatment of JB has a protective effect on LPS-induced ALI in mice. The anti-inflammatory mechanism of JB may be attributed to its suppression of NF-κB and MAPK activation.

Jolkinolide B inhibits RANKL-induced osteoclastogenesis by suppressing the activation NF-κB and MAPK signaling pathways

Osteoclasts together with osteoblasts play pivotal roles in bone remodeling. The unique function and ability of osteoclasts to resorb bone makes them critical in both normal bone homeostasis and pathologic bone diseases such as osteoporosis and rheumatoid arthritis. Thus, new compounds that may inhibit osteoclastogenesis and osteoclast function may be of great value in the treatment of osteoclast-related diseases. In the present study, we examined the effect of jolkinolide B (JB), isolated from the root of Euphorbia fischeriana Steud on receptor activator of NF-κB ligand (RANKL)-induced osteoclast formation. We found that JB inhibited RANKL-induced osteoclast differentiation from bone marrow macrophages (BMMs) without cytotoxicity. Furthermore, the expression of osteoclastic marker genes, such as tartrate-resistant acid phosphatase (TRAP), cathepsin K (CtsK), and calcitonin receptor (CTR), was significantly inhibited. JB inhibited RANKL-induced activation of NF-κB by suppressing RANKL-mediated IκBα degradation. Moreover, JB inhibited RANKL-induced phosphorylation of mitogen-activated protein kinases (p38, JNK, and ERK). This study thus identifies JB as an inhibitor of osteoclast formation and provides evidence that JB might be an alternative medicine for preventing and treating osteolysis.