Targeting ER Stress with Saikosaponin A to Overcome Resistance under Radiation in Gastric Cancer Cells

The circadian clock gene, BMAL1, promotes radiosensitization in nasopharyngeal carcinoma by inhibiting the epithelial-to-mesenchymal transition via the TGF-β1/Smads/Snail1 axis

Acquired radio-resistance is thought to be one of the main causes of recurrent metastasis after failure of nasopharyngeal carcinoma (NPC) radiotherapy, which may be related to X-ray-induced epithelial-mesenchymal transition (EMT) activation. The circadian clock gene, BMAL1, has been shown to correlate with the sensitivity of NPCs to radiotherapy, but the specific mechanism has not been reported. NPC cells were irradiated by conventional fractionation to generate radiotherapy-resistant cells. NPC cells with BMAL1 gene stabilization/overexpression and interference were obtained by lentiviral transfection. Western blotting, colony formation analysis, cell counting kit-8 assays, wound-healing tests, Transwell assays, flow cytometry, the EDU method, nuclear plasma separation experiments, HE staining, immunohistochemical staining and TUNEL staining were performed to explore the influence and molecular mechanism of the circadian clock gene, BMAL1, on NPC-acquired radio-resistance and EMT through in vitro and in vivo experiments. The results indicated that there was a gradual downregulation of BMAL1 gene protein expression during the routine dose induction of radio-resistance in NPC cells. EMT activation was present in the radiation-resistant cell line 5-8FR, and was accompanied by the significant enhancement of proliferation, migration and invasion. The BMAL1 gene significantly increased the radiosensitivity of the radiation-resistant cell line 5-8FR and reversed the acquired radio-resistance of NPCs, which was accomplished by inhibiting the TGF-β1/Smads/Snail1 axis-mediated EMT.

The dual effect of endoplasmic reticulum stress in digestive system tumors and intervention of Chinese botanical drug extracts: a review

Endoplasmic reticulum (ER) homeostasis is essential for maintaining human health, and once imbalanced, it will trigger endoplasmic reticulum stress (ERS), which participates in the development of digestive system tumors and other diseases. ERS has dual effect on tumor cells, activating adaptive responses to promote survival or inducing apoptotic pathways to accelerate cell death of the tumor. Recent studies have demonstrated that Chinese botanical drug extracts can affect the tumor process of the digestive system by regulating ERS and exert anticancer effects. This article summarizes the dual effect of ERS in the process of digestive system tumors and the intervention of Chinese botanical drug extracts in recent years, as reference for the combined treatment of digestive system tumors with Chinese and modern medicine.

Efficacy and safety of the traditional herbal medication Chai-Ling-Tang (in China), Siryung-tang (in Republic of Korea) or Sairei-To (in Japan)

ETHNOPHARMACOLOGICAL RELEVANCE

The herbal medicine designated Chai-Ling-Tang in China, Siryung-tang in South Korea, and Sairei-To (or Tsumura Saireito extract granules, TJ-114) in Japan is a complex polyherbal formulations with 12 plant components. It is used historically to treat Shaoyang syndrome, recorded in an ancient Chinese medical text "Treatise on Cold Damage Disorder" (Shanghan Lun). Chai-Ling-Tang formula combines two traditional Chinese herbal medicine prescriptions: Xiao-Chai-Hu-Tang and Wu-Ling-San (known as Sho-Saiko-To and Goreisan in Japan, and So Shi Ho Tang and Oreonsang in Korea, respectively). These traditional Chinese/Korean medicines and Kampo medicine have been used for more than 2000 years in East Asia, notably as regulators of body fluid homeostasis.

AIM OF THE STUDY

This study aims to evaluate clinical uses, pharmacological effects and unwanted effects of Sairei-To through a narrative literature survey. The main active phytoconstituents and their mechanism of actions are also collated based on the literature.

METHODS

Several databases including SciFinder and PubMed were searched in sourcing information using keywords corresponding to the medicinal treatment names and the corresponding plants and phytochemicals. Relevant textbooks, reviews, and digital documents (mostly in English) were consulted to collate all available scientific literature and to provide a complete science-based survey of the topic.

RESULTS

Sairei-To derives from ten plants and two fungi. The three major components are Bupleuri radix (Saiko), Pinelliae rhizoma (Hange), and Alismatis rhizoma (Takusha). The rest includes the species Scutellariae radix, Zizyphi fructus, Ginseng radix, Glycyrrhizae radix, Zingiberis rhizoma, Cinnamomi cortex, Atractylodis lanceae rhizoma, Poria sclerotium, and Polyporus sclerotium. The therapeutic uses of Sairei-To are very diversified, ranging from the treatment of autoimmune diseases, intestinal inflammatory disorders, edema, intestinal and kidney diseases, cancers, inflammatory skin pathologies, and other conditions such as reproductive failure. Sairei-To is considered as a safe and efficient medication, with potential rare unwanted side effects, notably lung injuries (pneumonitis essentially). Marked anti-inflammatory and immune-modulatory effects of Sairei-To have been reported, generally associated to the action of saponins (saikosaponins, glycyrrhizin), terpenoids (alisols) and flavonoids (baicalin, oroxylin A).

CONCLUSION

Sairei-To is commonly used to treat inflammatory diseases and appears efficient to decrease the side effects of corticosteroids. Its immune-regulatory action is well recognized and exploited to treat certain skin lesions and chemotherapy-related toxic effects. The activity of the Sairei-To product relies on the synergistic action of its individual ingredients. Further studies are warranted to quantify the synergy of action inherent to this interesting botanical medication.

Paeoniflorin Induces ER Stress-Mediated Apoptotic Cell Death by Generating Nox4-Derived ROS under Radiation in Gastric Cancer

Gastric cancer is one of the most prevalent cancer types worldwide, and its resistance to cancer therapies, such as chemotherapy and radiotherapy, has made treating it a major challenge. Paeoniflorin (PF) is one potential pharmacological treatment derived from paeony root. However, in cancer, the molecular mechanisms and biological functions of PF are still unclear. In the present study, we found that PF exerts anti-tumor effects in vivo and in vitro and induces apoptotic cell death through ER stress, calcium (Ca2+), and reactive oxygen species (ROS) release in gastric cancer cells. However, ROS inhibition by DPI and NAC blocks cell death and the PERK signaling pathway via the reduction of Nox4. Moreover, PF triggers a synergistic inhibitory effect of the epithelial-mesenchymal transition (EMT) process under radiation exposure in radiation-resistant gastric cancer cells. These findings indicate that PF-induced Ca2+ and ROS release overcomes radioresistance via ER stress and induces cell death under radiation in gastric cancer cells. Therefore, PF, in combination with radiation, may be a powerful strategy for gastric cancer therapy.