The therapeutic effects of Longikaurin A, a natural ent-kauranoid, in esophageal squamous cell carcinoma depend on ROS accumulation and JNK/p38 MAPK activation

Reactive Oxygen Species-Mediated Autophagy by Ursolic Acid Inhibits Growth and Metastasis of Esophageal Cancer Cells

Ursolic acid (UA) possesses various pharmacological activities, such as antitumorigenic and anti-inflammatory effects. In the present study, we investigated the mechanisms underlying the effects of UA against esophageal squamous cell carcinoma (ESCC) (TE-8 cells and TE-12 cells). The cell viability assay showed that UA decreased the viability of ESCC in a dose-dependent manner. In the soft agar colony formation assay, the colony numbers and size were reduced in a dose-dependent manner after UA treatment. UA caused the accumulation of vacuoles and LC3 puncta, a marker of autophagosome, in a dose-dependent manner. Autophagy induction was confirmed by measuring the expression levels of LC3 and p62 protein in ESCC cells. UA increased LC3-II protein levels and decreased p62 levels in ESCC cells. When autophagy was hampered using 3-methyladenine (3-MA), the effect of UA on cell viability was reversed. UA also significantly inhibited protein kinase B (Akt) activation and increased p-Akt expression in a dose-dependent manner in ESCC cells. Accumulated LC3 puncta by UA was reversed after wortmannin treatment. LC3-II protein levels were also decreased after treatment with Akt inhibitor and wortmannin. Moreover, UA treatment increased cellular reactive oxygen species (ROS) levels in ESCC in a time- and dose-dependent manner. Diphenyleneiodonium (an ROS production inhibitor) blocked the ROS and UA induced accumulation of LC3-II levels in ESCC cells, suggesting that UA-induced cell death and autophagy are mediated by ROS. Therefore, our data indicate that UA inhibits the growth of ESCC cells by inducing ROS-dependent autophagy.

Identification of Cytotoxic Constituents from the Whole Plant of Isodon ternifolius

A new oxygenated spiroketone, isodonspiroketone (1), and 4 known ones (2-5) were isolated from the whole plant of Isodon ternifolius (D.Don) Kudô. The structure of isodonspiroketone (1) was determined by nuclear magnetic resonance, mass spectroscopy, and circular dichroism spectral data. Compound 3 has not been previously isolated from I. ternifolius. Their cytotoxic activities were evaluated against A549, HepG2, and MDA-MB-231 cancer cell lines in vitro. New compound (isodonspiroketone, 1) showed moderate cytotoxic activities against A549, HepG2, and MDA-MB-231 cancer cell lines with half-maximal inhibitory concentration values of 23.84 ± 2.73, 27.77 ± 3.01, and 17.26 ± 1.61 μM, respectively; meanwhile, the others were inactive.

Neferine induces apoptosis by modulating the ROS‑mediated JNK pathway in esophageal squamous cell carcinoma

Current treatments for esophageal squamous cell carcinoma (ESCC) have limited efficacy. Therefore, the development of novel therapeutic targets to effectively manage the disease and boost survival rates is imperative Neferine, a natural product extracted from Nelumbo nucifera (lotus) leaves, has been revealed to inhibit the growth of hepatocarcinoma, breast cancer and lung cancer cells. However, its effect on ESCC is unknown. In the present study, it was revealed that neferine exerted anti‑proliferative effects in ESCC. It was also revealed that it triggered arrest of the G2/M phase and enhanced apoptosis of ESCC cell lines. Moreover, its ability to trigger accumulation of reactive oxygen species (ROS) and activate the c‑Jun N‑terminal kinase (JNK) pathway was demonstrated. Further study revealed how N‑acetyl cysteine (NAC), a ROS inhibitor, attenuated these effects, demonstrating that ROS and JNK inhibitors mediated a marked reversal of neferine‑triggered cell cycle arrest and apoptosis in ESCC cells. Finally, it was revealed that neferine was involved in the inhibition of Nrf2, an antioxidant factor. Collectively, these findings demonstrated the antitumor effect of neferine in ESCC, through the ROS‑mediated JNK pathway and inhibition of Nrf2, indicating its potential as a target for development of novel and effective therapeutic agents against ESCC.

Polyphyllin VI Induces Apoptosis and Autophagy via Reactive Oxygen Species Mediated JNK and P38 Activation in Glioma

Background

Polyphyllin VI (PPVI), a bioactive component derived from a traditional Chinese herb Paris polyphylla, exhibits potential antitumor activity against hepatocellular carcinoma, as well as breast and lung cancers. However, its effect on glioma remains unknown.

Methods

Five glioma cell lines (U251, U343, LN229, U87 and HEB) and an animal model were employed in the study. Anti-proliferation effects of PPVI were first determined using CCK-8 cell proliferation and clone formation assays, then reactive oxygen species (ROS), cell cycle progression and apoptosis effects measured by flow cytometry. The effect of PPVI on protein expression was quantified by Western blot analysis.

Results

Data showed that PPVI inhibited the proliferation of glioma cell lines by modulating the G2/M phase. Additionally, incubation of cells with PPVI promoted apoptosis, autophagy, increased accumulation of ROS and activated ROS-modulated JNK and p38 pathways. On the other hand, N-acetyl cysteine, a ROS inhibitor, attenuated PPVI-triggered effects. Furthermore, JNK and p38 inhibitors ameliorated PPVI-triggered autophagy and apoptosis in glioma cells. In vivo assays showed that PPVI inhibited tumor growth of U87 cell line in nude mice.

Conclusion

Overall, these data suggested that PPVI might be an effective therapeutic agent for glioma.

Cardamonin inhibits breast cancer growth by repressing HIF-1α-dependent metabolic reprogramming

Background

Cardamonin, a chalcone isolated from Alpiniae katsumadai, has anti-inflammatory and anti-tumor activities. However, the molecular mechanism by which cardamonin inhibits breast cancer progression largely remains to be determined.

Methods

CCK-8 and Hoechst 33258 staining were used to detect cell growth and apoptosis, respectively. HIF-1α driven transcription was measured by luciferase reporter assay. Glucose uptake and lactate content were detected with 2-NBDG and L-Lactate Assay Kit. Cell metabolism assays were performed on Agilent’s Seahorse Bioscience XF96 Extracellular Flux Analyzer. Mitochondrial membrane potential was measured with JC-1 probe. DCFH-DA was used to measure ROS level. Protein expression was detected by western blotting assay. Immunohistochemistry was performed to measure the expression of HIF-1α, LDHA and CD31 in tumor tissues.

Results

Cardamonin inhibited growth of the triple negative breast cancer cell line MDA-MB-231 in vitro and in vivo by suppressing HIF-1α mediated cell metabolism. Cardamonin inhibited the expression of HIF-1α at mRNA and protein levels by repressing the mTOR/p70S6K pathway, and subsequently enhanced mitochondrial oxidative phosphorylation and induced reactive oxygen species (ROS) accumulation. We also found that cardamonin inhibited the Nrf2-dependent ROS scavenging system which further increased intracellular ROS levels. Eventually, accumulation of the intracellular ROS induced apoptosis in breast cancer cells. In addition, cardamonin treatment reduced glucose uptake as well as lactic acid production and efflux, suggesting its function in repressing the glycolysis process.

Conclusions

These results reveal novel function of cardamonin in modulating cancer cell metabolism and suppressing breast cancer progression, and suggest its potential for breast cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1351-4) contains supplementary material, which is available to authorized users.

Apoptotic Pathway as the Therapeutic Target for Anticancer Traditional Chinese Medicines

Cancer is a leading cause of morbidity and mortality worldwide. Apoptosis is a process of programmed cell death and it plays a vital role in human development and tissue homeostasis. Mounting evidence indicates that apoptosis is closely related to the survival of cancer and it has emerged as a key target for the discovery and development of novel anticancer drugs. Various studies indicate that targeting the apoptotic signaling pathway by anticancer drugs is an important mechanism in cancer therapy. Therefore, numerous novel anticancer agents have been discovered and developed from traditional Chinese medicines (TCMs) by targeting the cellular apoptotic pathway of cancer cells and shown clinically beneficial effects in cancer therapy. This review aims to provide a comprehensive discussion for the role, pharmacology, related biology, and possible mechanism(s) of a number of important anticancer TCMs and their derivatives mainly targeting the cellular apoptotic pathway. It may have important clinical implications in cancer therapy.

Bavachinin Induces Oxidative Damage in HepaRG Cells through p38/JNK MAPK Pathways

Drug-induced liver injury is one of the main causes of drug non-approval and drug withdrawal by the Food and Drug Administration (FDA). Bavachinin (BVC) is a natural product derived from the fruit of the traditional Chinese herb Fructus Psoraleae (FP). There have been reports of acute liver injury following the administration of FP and its related proprietary medicines. To explore BVC hepatotoxicity and its mechanisms, we used the HepaRG cell line. In our recent research, we showed that BVC induces HepaRG cell death, mainly via BVC-induced oxidative damage. The formation of ROS is closely related to the activation of the stress-activated kinases, JNK and p38, while SP600125 (SP, JNK inhibitor) and SB203580 (SB, p38 inhibitor) pretreatment inhibited the generation of ROS. On the other hand, N-acetylcysteine (NAC) pretreatment prevented the phosphorylation of p38 but not that of JNK. Taken together, these data reveal that BVC induces HepaRG cell death via ROS and the JNK/p38 signaling pathways.