Retracted : Syringic acid suppresses oral squamous cell carcinoma SCC131 cell proliferation via modulation of mitochondria‐mediated apoptosis signaling pathways

Vernodalin Triggers ROS-Mediated Apoptosis in TPC-1 Human PapillaryThyroid Cancer Cells via Suppression of the MAPKs Signaling Pathway

BACKGROUND

Thyroid Cancer (TC) is an endocrine organ malignancy that has become more common in recent decades. Vernodalin (VN), a cytotoxic sesquiterpene, has been reported to exhibit anticancer properties against human breast and liver cancer cells. However, no study has explored the efficacy of VN with respect to its antiproliferative and apoptotic action on human Papillary Thyroid Cancer cells (PTC).

OBJECTIVE

The study intended to examine the antitumor and antiproliferative effects of VN and the apoptosis mechanisms underlying its action on TPC-1 human PTC cells.

METHODS

In this study, we examined the VN cell viability by MTT assay; performed ROS measurement by DCFH staining method, MMP identification by Rh-123 staining method, and apoptotic morphological assay by employing AO/EB and DAPI stain method, and further, p38 MAPK/ERK/JNK cell proliferation markers were determined by western blotting technique.

RESULTS

The findings showed that VN could inhibit the growth of PTC cells by increasing intracellular ROS, damaging MMP, and stimulating apoptosis in a concentration-dependent manner. The study demonstrated how VN inhibited TPC-1 cell viability by causing ROS-induced cell death via the MAPK signaling pathway.

CONCLUSION

VN may serve as an agonist to impact apoptosis in PTC cells. In human PTC, VN could play an effective role in chemotherapy. More studies pertaining to animal tumor models are needed to prove its anti-cancer effectiveness in vivo.

Effects of Syringic Acid on Apoptosis, Inflammation, and AKT/mTOR Signaling Pathway in Gastric Cancer Cells

Gastric cancer is one of the most common cancer and deadly disease worldwide. Despite substantial advances made in the treatment of gastric cancer, existing therapies still encounter bottlenecks. Chemotherapy, for instance, could lead to serious side effects, high drug resistance and treatment failure. Phytochemical-derived compounds from plants offer novel strategies as potent drug molecules in cancer therapy. Given the low toxicity and higher tolerance rate of naturally occurring compounds, the present study evaluated the effects of syringic acid on cytotoxicity, oxidative stress, mitochondrial membrane potential, apoptosis, and inflammatory responses in gastric cancer cell line (AGS). AGS cells were treated with various concentrations (5-40 μg/mL) of syringic acid for 24 h, after which cytotoxicity was analyzed. Reactive Oxygen Species (ROS), antioxidant enzyme activities, mitochondrial membrane potential (MMP, Δψ _m), cell morphologies, the expression of apoptotic markers and protein expression patterns were also investigated. Results indicated that syringic acid-treated cells developed anti-cancer activities by losing MMP, cell viability, and enhancing intracellular ROS. Syringic acid selectively developed apoptosis in a dose-dependent manner via enhanced regulation of caspase-3, caspase-9 and Poly ADP-ribose Polymerase (PARP) whereas decreasing the expression levels of p53 and BCL-2. Syringic acid also lowered activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) whereas Thio Barbituric Acid Reactive Substances (TBARS) increased. Syringic acid suppressed gastric cancer cell proliferation, inflammation, and induced apoptosis by upregulating mTOR via AKT signaling pathway. The study suggests syringic acid may constitute a promising chemotherapeutic candidate for gastric cancer treatment. Our study is the first report on the anti-cancer effects of syringic acid against gastric cancer cells via apoptosis, inhibition of inflammation, and the suppression of the mTOR/AKT signaling pathway.

Inhibiting the JNK/ERK signaling pathway with geraniol for attenuating the proliferation of human gastric adenocarcinoma AGS cells

Geraniol, a natural compound found in the essential oils of various aromatic plants, has attracted attention for its probable anticancer effects. The molecular mechanisms of the cell proliferation suppression and apoptosis induction via geraniol in gastric cancer cells (AGS), however, remain unclear. Gastric cancer cells were treated with geraniol, and it was found that the IC₅₀ values were 25 μM/ml, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results showed that 20 and 25 μM geraniol-induced reactive oxygen species (ROS) production (2'-7'dichlorofluorescin diacetate staining) and decreased mitochondrial membrane potential (rhodamine 123 staining) in AGS cells. Then, it effectively inhibited cell growth and induced apoptosis, confirmed through acridine orange/ethidium bromide, 4',6-diamidino-2-phenylindole, and propidium iodide staining and molecular marker analysis in AGS cells. Also, geraniol potently diminished caspase-9, Bax, Bcl-2, and caspase-3 expression in AGS cells. We also evaluated the essential mechanism of the cytotoxic effect of geraniol. Moreover, the present study depicted that geraniol-induced cell death through mitochondrial ROS production and inhibited the phosphorylation form of mitogen-activated protein kinase (p38, MAPK, JNK, and ERK1/2) signaling pathway. Taken together, these results concluded that geraniol has a novel therapeutic property against human stomach cancer.

Syringic Acid Alleviates Cesium-Induced Growth Defect in Arabidopsis

Syringic acid, a phenolic compound, serves a variety of beneficial functions in cells. Syringic acid increases in plants in response to cesium, and exogenous application of syringic acid resulted in a significant attenuation of cesium-induced growth defects in Arabidopsis. In addition, cesium or syringic acid application to plants also resulted in increased lignin deposition in interfascicular fibers. To better understand the role of lignin and syringic acid in attenuating cesium-induced growth defects, two mutants for Arabidopsis REDUCED EPIDERMAL FLUORESCENE 4 (REF4) and fourteen laccase mutants, some of which have lower levels of lignin, were evaluated for their response to cesium. These mutants responded differently to cesium stress, compared to control plants, and the application of syringic acid alleviated cesium-induced growth defects in the laccase mutants but not in the ref4 mutants. These findings imply that lignin plays a role in cesium signaling but the attenuation of cesium stress defects by syringic acid is mediated by regulatory components of lignin biosynthesis and not lignin biosynthesis itself. In contrast, syringic acid did not alleviate any low potassium-induced growth defects. Collectively, our findings provide the first established link between lignin and cesium stress via syringic acid in plants.