A Nudibranch Marine Extract Selectively Chemosensitizes Colorectal Cancer Cells by Inducing ROS-Mediated Endoplasmic Reticulum Stress

Activation of endoplasmic reticulum stress by harmine suppresses the growth of esophageal squamous cell carcinoma

The worldwide overall 5-year survival rate of esophageal squamous cell carcinoma (ESCC) patients is less than 20%, and novel therapeutic strategies for these patients are urgently needed. Harmine is a natural β-carboline alkaloid, which received great interest in cancer research because of its biological and anti-tumor activities. The aim of this study is to examine the effects of harmine on ESCC and its mechanism. We investigated the effects of harmine on proliferation, cell cycle, apoptosis, and tumor growth in vivo. RNA sequencing (RNA-seq), real-time PCR, and western blotting were used to detect the mechanism. Harmine inhibited ESCC cell growth in vitro and tumor growth in vivo. Differentially expressed genes in harmine-treated ESCC cells were mainly involved in protein processing in the endoplasmic reticulum (ER). Real-time PCR and western blotting confirmed harmine-induced cellular ER stress. CRISPR-Cas9 knockout of C/EBP homologous protein (CHOP) abolished harmine-induced expression of death receptor 5 and apoptosis. Harmine also induced the expression of CHOP-mediated sestrin-2, which in turn contributes to autophagosome formation via suppressing the AMP-activated protein kinase-protein kinase B-mammalian target of rapamycin signaling pathway. In conclusion, our results demonstrate that harmine inhibits the growth of ESCC through its regulation of ER stress, suggesting that it is a promising candidate for ESCC treatment.

Identification of chemosensitizing agents of colorectal cancer in Rauvolfia vomitoria using an NMR-based chemometric approach

Searching for new adjuvants of conventional chemotherapeutic approaches against colorectal cancer cells is extremely urgent. In current research, a non-targeted analytical approach was established by combining proton nuclear magnetic resonance spectroscopy with a chemometrics data mining tool to identify chemosensitizing agents from Rauvolfia vomitoria. This approach enabled the identification of potential active constituents in the initial fractionation process and provided their structural information. This strategy was validated by its application to Rauvolfia vomitoria extract exhibiting chemosensitizing activity on 5-fluorouracil against colorectal cancer cells. After the workflow, the biochemometrics analysis showed that at least 15 signals (Variable influence on projection (VIP) > 1) could have contributions in the differentiation of various fractions. Through systematic literature and database searches, we found that the most active fraction (fraction 7) exhibited the highest presence of sabazin-type and armaniline-type alkaloids, which were potential chemosensitizers as previously reported. To validate the results of the strategy, the effect of 5-FU and compounds isolated from fraction seven incubation on HCT-8 and LoVo cell vialibilty were evaluated. These results evidenced that compound β-carboline (3), 1-methyl-β-carboline (4), and lochnerine (6) could enhance the cytotoxicity of 5-fluorouracil against to Colorectal cancer cells. Besides, 21 compounds including two new compounds were isolated from Rauvolfia vomitoria. The experimental results verify the reliability of the method, and this approach provides a new and efficient tool to overcome some of the bottlenecks in natural products drug discovery.

Echinacoside inhibited cardiomyocyte pyroptosis and improved heart function of HF rats induced by isoproterenol via suppressing NADPH/ROS/ER stress

Prevalence of heart failure (HF) continues to rise over time and is a global difficult problem; new drug targets are urgently needed. In recent years, pyroptosis is confirmed to promote cardiac remodelling and HF. Echinacoside (ECH) is a natural phenylethanoid glycoside and is the major active component of traditional Chinese medicine Cistanches Herba, which is reported to possess powerful anti‐oxidation and anti‐inflammatory effects. In addition, we previously reported that ECH reversed cardiac remodelling and improved heart function, but the effect of ECH on pyroptosis has not been studied. So, we investigated the effects of ECH on cardiomyocyte pyroptosis and the underlying mechanisms. In vivo, we established HF rat models induced by isoproterenol (ISO) and pre‐treated with ECH. Indexes of heart function, pyroptotic marker proteins, ROS levels, and the expressions of NOX2, NOX4 and ER stress were measured. In vitro, primary cardiomyocytes of neonatal rats were treated with ISO and ECH; ASC speckles and caspase‐1 mediated pyroptosis in cardiomyocytes were detected. Hoechst/PI staining was also used to evaluate pyroptosis. ROS levels, pyroptotic marker proteins, NOX2, NOX4 and ER stress levels were all tested. In vivo, we found that ECH effectively inhibited pyroptosis, down‐regulated NOX2 and NOX4, decreased ROS levels, suppressed ER stress and improved heart function. In vitro, ECH reduced cardiomyocyte pyroptosis and suppressed NADPH/ROS/ER stress. We concluded that ECH inhibited cardiomyocyte pyroptosis and improved heart function via suppressing NADPH/ROS/ER stress.

Natural Marine Products: Anti-Colorectal Cancer In Vitro and In Vivo

Colorectal cancer, a malignant tumor with high mortality, has a poor prognosis due to drug resistance and toxicity in clinical surgery and chemotherapy. Thus, finding safer and more efficient drugs for clinical trials is vital and urgent. Natural marine compounds, with rich resources and original chemical structures, are applied widely in anticancer treatments. We provide a systematic overview of recently reported marine compounds such as alkaloids, peptides, terpenoids, polysaccharides, and carotenoids from in vitro, in vivo, and clinical studies. The in vitro studies summarized the marine origins and pharmacological mechanisms, including anti-proliferation, anti-angiogenesis, anti-migration, anti-invasion, the acceleration of cycle arrest, and the promotion of tumor apoptosis, of various compounds. The in vivo studies outlined the antitumor effects of marine compounds on colorectal cancer model mice and evaluated their efficacy in terms of tumor inhibition, hepatotoxicity, and nephrotoxicity. The clinical studies summarized the major chemical classifications and targets of action of the clinical drugs that have entered clinical approval and completed approval for marine anticancer. In summary, we present the current situation regarding the application of natural anti-colorectal cancer marine compounds and prospects for their clinical application.

The innate immune system and fever under redox control: A Narrative Review

ABSTRACT:

In living cells, redox potential is vitally important for normal physiological processes that are closely regulated by antioxidants, free amino acids and proteins that either have reactive oxygen and nitrogen species capture capability or can be compartmentalized. Although hundreds of experiments support the regulatory role of free radicals and their derivatives, several authors continue to claim that these perform only harmful and non-regulatory functions. In this paper we show that countless intracellular and extracellular signal pathways are directly or indirectly linked to regulated redox processes. We also briefly discuss how artificial oxidative stress can have important therapeutic potential and the possible negative effects of popular antioxidant supplements.