An autophagy-dependent cell death of MDA-MB-231 cells triggered by a novel Rhein derivative 4F.

Triple negative breast cancer (TNBC) has very poor prognosis and no efficacious therapeutic options due to the absence of a validated molecular target. Therefore, novel therapeutic strategies against TNBC are urgently needed. Our team synthesized and screened a series of compounds derived from Rhein, of which 4F was selected for further analysis based on its ability to produce the vacuolated appearance of cells. Using Cell counting kit-8 assay, colony-formation assay, cell apoptosis and cell cycle assay, we compared the antitumor effects of 4F, Rhein and Cisplatin on a TNBC cell line MDA-MB-231 in vitro. The vacuoles in MDA-MB-231 cells were observed and analyzed by hematoxylin-eosin staining and transmission electron microscopy. Autophagy and apoptosis-related proteins including p62, Microtubule Light Chain 3 (LC3), Beclin-1 and Caspase-3 were determined by western blot. The tandem mRFP-GFP-LC3 Lentivirus was used for monitoring the maturation step of autophagosomes. Our data revealed that 4F had lower cytotoxicity to normal breast cell line MCF-10A as compared with positive drug Doxorubicin. Although 4F had better cytotoxicity than Rhein, it had no influence on cells apoptosis in 4F-treated cells. Accumulation of autolysosomes and autophagosomes was observed in 4F-treated MDA-MB-231 cells, accompanied by increased level of Beclin-1 protein. Enhanced autophagic flux was verified by higher ratio of LC3-II/LC3-I, the degradation of p62 protein and alteration in red and green fluorescence puncta. These findings suggested that the process of MDA-MB-231 cell death induced by 4F seemed rely mainly on autophagy rather than apoptosis. 4F may be an alternative drug candidate against TNBC and merits more exploration.

One-Year Survival for Developing Acute Kidney Injury in Adult Patients with AMI Cardiogenic Shock Receiving Venoarterial Extracorporeal Membrane Oxygenation.

Objective: The incidence of cardiogenic shock cases treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support has been on the rise. Acute kidney injury (AKI) is a significant complication of cardiogenic shock and a frequent serious complication in patients requiring ECMO-supported therapy. AKI is strongly associated with unfavorable patient prognosis. However, there is a paucity of data on the influence of AKI on the prognosis of patients with acute myocardial infarction complicated by cardiogenic shock (AMI-CS) who are receiving ECMO support, particularly with regard to long-term outcomes. Methods: This retrospective observational study included 103 patients in the People's Hospital of Guangxi Zhuang Autonomous Region from January 2017 and June 2022. AKI was defined according to Kidney Disease Improving Global Outcome (KDIGO) criteria. Cox regression and logistic regression were used to identify risk factors. Results: In this study, the incidence of AKI was 63.11%, with AKI stage 1, 2, and 3 accounting for 21.36%, 12.62%, and 29.13%, respectively. Patients with severe AKI had significantly higher in-hospital mortality (43.33% vs 27.40%, P < 0.001), 30-day mortality (60.00% vs 31.51%, P = 0.001), and 1-year mortality (63.67% vs 34.25%, P<0.001) than those without severe AKI. Furthermore, severe AKI significantly increased the risk of one-year mortality (HR 10.816, CI 3.118-37.512, P<0.001). Baseline serum creatinine, baseline platelet, and active cardiopulmonary resuscitation were independent predictors of one-year mortality. In addition, baseline white blood cell count, baseline aspartate aminotransferase, baseline alanine aminotransferase (ALT), baseline serum creatinine, preoperative lactate, and postoperative mean arterial pressure were independent risk factors of severe AKI during hospitalization. Conclusion: In patients with AMI-CS receiving ECMO support, AKI is highly prevalent. Development of severe AKI significantly increased the risk of one-year mortality.

Rhein Derivative 4F Inhibits the Malignant Phenotype of Breast Cancer by Downregulating Rac1 Protein.

BACKGROUND: Triple-negative breast cancer is a common malignant tumor with unfavorable prognosis affecting women worldwide; thus, there is an urgent need for novel therapeutic drugs with improved anti-tumor activity. Rac family small GTPase 1 (Rac1) plays an important role in malignant behavior and is a promising therapeutic target. We reported an anthraquinone compound, Rhein, and its derivative, 4F, and investigated their downregulation effects on Rac1 in breast cancer cells in vitro. METHODS: The inhibition of cell proliferation by derivative 4F was investigated in two breast cancer (MDA-MB-231 and MCF-7) and normal breast (MCF-10A) cell lines by cell counting kit-8 assay and growth curves. The role of 4F in cell migration and invasion and cytoskeletal change were assessed by Transwell chamber assay and F-actin staining, respectively. The affinity of Rhein and its derivative for Rac1 protein and the regulation of Rac1 promoter activity were evaluated by molecular docking software and luciferase reporter gene assay, respectively. Rac1 protein expression was determined by western blot assay. RESULTS: Compared to Rhein, derivative 4F more strongly inhibited breast cancer cell proliferation, migration, and invasion and also cause cytoskeletal changes like those in paclitaxel. Derivative 4F not only bound more stably to Rac1 but also inhibited Rac1 promoter activity in cells and downregulated Rac1 protein expression. CONCLUSIONS: Rhein derivative 4F is a new anthraquinone compound with better anti-tumor activity than that of the lead compound Rhein in breast cancer. It down-regulated Rac1 expression and may be a small molecule inhibitor of Rac1.

Confirming whether novel rhein derivative 4a induces paraptosis-like cell death by endoplasmic reticulum stress in ovarian cancer cells.

Ovarian cancer is the leading cause of death among gynecologic cancer patients. Although platinum-based chemotherapy as a frontline treatment for ovarian cancer has been widely used in clinical settings, its clinical efficacy is not satisfactory due to the resistance of ovarian cancer cells to apoptosis. Therefore, it is of great significance to induce non-apoptotic programed cell death patterns, such as paraptosis, in ovarian cancer. In this study, we aimed to explore the potential anticancer mechanisms of novel rhein derivative 4a, which was modified with rhein as a lead compound. The results showed that a wide range of vacuoles from the endoplasmic reticulum and mitochondria appeared in ovarian SKOV3, SKOV3-PM4, and A2780 cells treated with derivative 4a, and the cell death caused by derivative 4a is a type of non-apoptotic and non-autophagic death, which is caused by expansion and damage of the endoplasmic reticulum or mitochondria, showing the characteristics of para-apoptotic death. Furthermore, derivative 4a stimulated the unfolded protein reaction of ovarian cancer cells by upregulating the expression of Bip78 and activating the PERK-eIF2α-ATF4 pathways. Notably, rhein derivative 4a-induced cell death was positively correlated with activation of p38, ERK, and JNK, and negatively correlated with Alix, a known protein that inhibits paraptosis. In addition, derivative 4a treatment also induced G2/M phase arrest in ovarian cancer cells. Taken together, our study reveals that derivative 4a induces paraptosis, and this finding can serve as a basis in developing a new strategy for the treatment of antiapoptotic ovarian cancer.