Osthole induced apoptosis in human normal liver cells by regulating cell proliferation and endoplasmic reticulum stress

Endoplasmic reticulum stress-mediated cell death in liver injury

The endoplasmic reticulum is an important intracellular organelle that plays an important role in maintaining cellular homeostasis. Endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) are induced when the body is exposed to adverse external stimuli. It has been established that ERS can induce different cell death modes, including autophagy, apoptosis, ferroptosis, and pyroptosis, through three major transmembrane receptors on the ER membrane, including inositol requirement enzyme 1α, protein kinase-like endoplasmic reticulum kinase and activating transcription factor 6. These different modes of cell death play an important role in the occurrence and development of various diseases, such as neurodegenerative diseases, inflammation, metabolic diseases, and liver injury. As the largest metabolic organ, the liver is rich in enzymes, carries out different functions such as metabolism and secretion, and is the body's main site of protein synthesis. Accordingly, a well-developed endoplasmic reticulum system is present in hepatocytes to help the liver perform its physiological functions. Current evidence suggests that ERS is closely related to different stages of liver injury, and the death of hepatocytes caused by ERS may be key in liver injury. In addition, an increasing body of evidence suggests that modulating ERS has great potential for treating the liver injury. This article provided a comprehensive overview of the relationship between ERS and four types of cell death. Moreover, we discussed the mechanism of ERS and UPR in different liver injuries and their potential therapeutic strategies.

Osthole: An up-to-date review of its anticancer potential and mechanisms of action

With its high incidence and mortality rates, cancer is one of the largest health problems worldwide. Investigating various cancer treatment options has been the focus of many domestic and international researchers, and significant progress has been made in the study of the anticancer effects of traditional Chinese medicines. Osthole, a coumarin compound extracted from Cnidium monnieri (L.) Cuss., has become a new research hotspot. There have been many reports on its anticancer effects, and recent studies have elucidated that its underlying mechanism of action mainly involves inhibiting cancer cell proliferation, inducing cancer cell apoptosis, inhibiting invasion and migration of cancer cells, inhibiting cancer angiogenesis, increasing sensitivity to chemotherapy drugs, and reversing multidrug resistance of cancer cells. This mini-review summarizes the research progress on the anticancer effects of osthole in recent years.

Betulinic acid attenuates T-2 toxin-induced cytotoxicity in porcine kidney cells by blocking oxidative stress and endoplasmic reticulum stress

T-2 toxin is highly cytotoxic to animals, which causes damage to animal health and great economic losses to agriculture and livestock production. Betulinic acid (BA), a naturally occurring pentacyclic lupane-type triterpenoid, has various biological and medicinal activities in vivo and in vitro. The objective of the present study was to investigate the toxic effects of T-2 toxin and the reversal effect of BA on porcine kidney (PK-15) cells. We evaluated T-2 toxin-induced apoptotic responses via oxidative stress and endoplasmic reticulum stress pathways by assessing the repair effect of BA in PK-15 cells. The results proved that T-2 toxin (1 μM, treated for 24 h) is highly toxic to PK-15 cells. After pre-treatment with BA (0.25, 0.5, and 1 μM) for 24 h, the cell viabilities were significantly increased, and the lactate dehydrogenase (LDH) in the culture media was dramatically decreased compared to that in the T-2 toxin treatment group. BA also enhanced the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and catalase (CAT) and reduced the production of reactive oxygen species (ROS) and malondialdehyde (MDA) in cells. BA also dose-dependently increased the expression of glucose regulated protein (GRP78), reduced expression of activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), the phosphorylation of protein kinase R-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor 2α (eIF2α), and intracellular Ca²⁺ concentration in a dose-dependent manner. In addition, BA significantly decreased the expression of cleaved-caspase-3 and caspase-12, consequently reducing T-2 toxin-induced PK-15 cell apoptosis in a dose-dependent manner. Collectively, we suggest that BA has a protective effect on T-2 toxin-induced cytotoxicity by ameliorating oxidative stress and endoplasmic reticulum stress in PK-15 cells.

Osthole induces apoptosis of the HT-29 cells via endoplasmic reticulum stress and autophagy

Endoplasmic reticulum stress (ERS) and autophagy are important pathways, which induce apoptosis of tumor cells. Osthole has been demonstrated to exert anticancer effects via the induction of apoptosis in several human colon cancer lines, but the mechanism underlying its involvement in the induction of ERS and autophagy in the human HT-29 colorectal cancer cell line remains unknown. The present study aimed to identify the possible signaling pathways involved in osthole-induced apoptosis of HT29 cells. Methodologically, colony formation and Cell Counting Kit-8 assays were used to assess cell proliferation and viability, respectively, while flow cytometry was performed to investigate apoptosis. Signaling pathways, including apoptosis, autophagy and ERS, were also investigated in the HT-29 cell line using western blot analysis. The results demonstrated that osthole inhibited cellular proliferation and viability in a dose-dependent manner. In addition, osthole induced the expression level of proteins associated with mitochondria-mediated cell apoptosis, autophagy and ERS. The association between autophagy and ERS in osthole-induced apoptosis in the HT-29 cell line was further clarified. Inhibiting cell autophagy with the inhibitor, 3-methyladenine, suppressed osthole-induced cell apoptosis and enhanced osthole-induced ERS. By contrast, alleviating ERS with the inhibitor, 4-phenylbutyric acid attenuated osthole-induced cell apoptosis and autophagy. In conclusion, osthole could significantly suppress the proliferation and viability of the HT-29 colorectal cancer cell line and induce cell apoptosis via autophagy and ERS. Furthermore, ERS may play a more important role in osthole-induced cell apoptosis.

The toxic effects of titanium dioxide nanoparticles on plasma glucose metabolism are more severe in developing mice than in adult mice

Titanium dioxide nanoparticles (TiO₂ NPs) are authorized food additives, and children have the highest exposure. Therefore, children are likely more susceptible to the adverse effects of TiO₂ NPs than adults. Previous study showed that oral administration of 50 mg/kg body weight (bw) TiO₂ NPs increase plasma glucose in mice. However, few studies have directly compared the adverse effects of exposure to TiO₂ NPs on plasma glucose metabolism of different age groups. In this study, the developing (age 3 weeks) and adult mice (age 10 weeks) were orally administered with 50 mg/kg bw TiO₂ NPs per day. The TiO₂ NPs induced hyperglycemia earlier in the developing mice than in the adult mice. Then mechanisms were analyzed after mice were oral administration of TiO2 NPs for 8 weeks and 26 weeks, respectively. Results showed that the treatment with TiO₂ NPs activated xenobiotic biodegradation in livers of both developing and adult mice at the early stage. However, only in the developing mice, TiO₂ NPs induced endoplasmic reticulum (ER) stress in livers and increased reactive oxygen species in livers and sera in the early stage. The ER stress and ROS activated an inflammation response and mitogen-activated protein kinase pathways, thereby inducing insulin resistance in the livers of developing mice at the early stage. The response of the adult mice was delayed, and these changes were observed in the late stage of the study. The results of this study all suggest that children are more susceptible than adults to the toxicity of orally administered TiO₂ NPs.

Expression of glucose-regulated protein 78 as prognostic biomarkers for triple-negative breast cancer

INTRODUCTION

Glucose-regulated protein78(GRP78) is a stress - induced endoplasmic reticulum chaperone protein. it is closely related to the occurrence, development, proliferation, differentiation and drug resistance of breast cancer. However, the association and clinicopathological features between GRP78 and triple negative breast cancer (TNBC) remain to be studied.

MATERIAL AND METHODS

Clinical and pathological characteristics and overall survival were analysed retrospectively in 179 surgically resected TNBC patients. GRP78 was detected by immunohistochemistry (IHC) using breast cancer tissue microarrays (TMAs), and the association between GRP78 levels and clinicopathological factors and prognosis was analyzed. Furthermore, GRP78 expression in human TNBC and NTNBC cell lines was detected by Western blot and qRT-PCR. After Si-GRP78 knocked-down GRP78 in MDA-MB-231 and BT549 cell lines, cell proliferation was detected using Cell Counting Kit-8 (CCK-8) and cell colony formation was detected by crystal violet staining, respectively.

RESULTS

GRP78 was expressed in triple negative breast cancer (TNBC). GRP78 expression was significantly associated with invasive, distant metastasis and proliferation of TNBC (P<0.05). In addition, patients with positive GRP78 expression had shorter overall survival (OS) and disease-free survival (DFS). And the high expression of GRP78 was significantly associated with disease-free survival (DFS) in patients with TNBC (P<0.001).

CONCLUSIONS

These findings improve our understanding of the expression pattern of GRP78 in TNBC and clarify the role of GRP78 as promising prognostic biomarkers for triple-negative breast cancer.