Targeting endoplasmic reticulum stress signaling in ovarian cancer therapy

EM-12, a natural sesquiterpene lactone extracted from Elephantopus mollis, promotes cancer cell apoptosis by activating ER stress

The Elephantopus mollis H.B.K. contains various sesquiterpene lactones that have shown anti-proliferative and proapoptotic effects in various cancers, although the underlying mechanisms are partially understood. Inducing of excessive ER stress is a potential cancer therapeutic strategy. However, ER stress activator remain limited in current clinical applications. In this study, we identified that EM-12, an uncovered sesquiterpene lactone isolated from Elephantopus mollis H.B.K., as a BiP ATPase activity inhibitor through BiP ATPase activity assay in vitro. This molecule also exhibits significantly greater cytotoxicity in numerous ovarian cancer cell lines, including paclitaxel-resistance ovarian cancer cell line, compared to transformed ovarian epithelial cell lines. In addition, EM-12 exerts broad-spectrum cytotoxicity against various human cancer cell lines, including liver, nasopharyngeal, and breast cancer cell lines. Mechanically, EM-12 promotes ER stress and ER-stress-related apoptosis to against cancer cells through inhibiting BiP ATPase activity.

Endoplasmic reticulum stress response pathway-mediated cell death in ovarian cancer

The endoplasmic reticulum (ER) is one of the largest organelles, and Endoplasmic Reticulum Stress Response Pathway is a series of responses triggered by the homeostatic imbalance of the ER and the state in which unfolded or misfolded proteins accumulate in the ER, which can trigger cell death. Cell death plays a crucial role in the development of diseases such as gynecological oncology. Herein, we review the current research on the response and ovarian cancer, discussing the key sensors (IRE1, PERK, ATF6), and the conditions under which it occurs (Ca2+ homeostasis disruption, hypoxia, others). Using the response as a starting point, provide a comprehensive overview of the relationship with the four types of cell death (apoptosis, autophagy, immunogenic cell death, paraptosis) in an attempt to provide new targeted therapeutic strategies for the organelle-Endoplasmic Reticulum Stress Response Pathway-cell death in ovarian cancer therapy.

Targeting Endoplasmic Reticulum Stress by Natural and Chemical Compounds Ameliorates Cisplatin-Induced Nephrotoxicity: A Review

Cisplatin is a chemotherapeutic that dose-dependently causes renal complications such as decreased kidney function and acute kidney injury. The endoplasmic reticulum (ER) is responsible for calcium homeostasis and protein folding and plays a major part in cisplatin's nephrotoxicity. The current article reviews how chemical and natural compounds modulate cisplatin-induced apoptosis, autophagy, and inflammation by inhibiting ER stress signaling pathways. The available evidence indicates that natural compounds (Achyranthes aspera water-soluble extract, morin hydrate, fucoidan, isoliquiritigenin, leonurine, epigallocatechin-3-gallate, grape seed proanthocyanidin, and ginseng polysaccharide) and chemicals (Sal003, NSC228155, TUG891, dorsomorphin (compound C), HC-030031, dexmedetomidine, and recombinant human erythropoietin (rHuEpo)) can alleviate cisplatin nephrotoxicity by suppression of ER stress signaling pathways including IRE1α/ASK1/JNK, PERK-eIF2α-ATF4, and ATF6, as well as PI3K/AKT signaling pathway. Since ER and related signaling pathways are important in cisplatin nephrotoxicity, agents that can inhibit the abovementioned signaling pathways may hold promise in alleviating this untoward adverse effect.

Independent organelle and organelle-organelle interactions: essential mechanisms for malignant gynecological cancer cell survival

Different eukaryotic cell organelles (e.g., mitochondria, endoplasmic reticulum, lysosome) are involved in various cancer processes, by dominating specific cellular activities. Organelles cooperate, such as through contact points, in complex biological activities that help the cell regulate energy metabolism, signal transduction, and membrane dynamics, which influence survival process. Herein, we review the current studies of mechanisms by which mitochondria, endoplasmic reticulum, and lysosome are related to the three major malignant gynecological cancers, and their possible therapeutic interventions and drug targets. We also discuss the similarities and differences of independent organelle and organelle-organelle interactions, and their applications to the respective gynecological cancers; mitochondrial dynamics and energy metabolism, endoplasmic reticulum dysfunction, lysosomal regulation and autophagy, organelle interactions, and organelle regulatory mechanisms of cell death play crucial roles in cancer tumorigenesis, progression, and response to therapy. Finally, we discuss the value of organelle research, its current problems, and its future directions.

A novel CSN5/CRT O-GlcNAc/ER stress regulatory axis in platinum resistance of epithelial ovarian cancer

Background: High levels of COP9 signalosome subunit 5 (CSN5) in epithelial ovarian cancer (EOC) are associated with poor prognosis and are implicated in mediating platinum resistance in EOC cells. The underlying mechanisms, however, remained undefined. This study aimed to elucidate the molecular process and identify potential therapeutic targets. Methods: RNA-sequencing was used to investigate differentially expressed genes between platinum-resistant EOC cells with CSN5 knockdown and controls. O-GlcNAc proteomics were employed to identify critical modulators downstream of CSN5. The omics findings were confirmed through qRT-PCR and immunoblotting. In vitro and in vivo experiments assessed the sensitivity of resistant EOCs to platinum. Results: We demonstrated an involvement of aberrant O-GlcNAc and endoplasmic reticulum (ER) stress disequilibrium in CSN5-mediated platinum resistance of EOC. Genetic or pharmacologic inhibition of CSN5 led to tumor regression and surmounted the intrinsic EOC resistance to platinum both in vitro and in vivo. Integration of RNA-sequencing and O-GlcNAc proteomics pinpointed calreticulin (CRT) as a potential target of aberrant O-GlcNAc modification. CSN5 upregulated O-GlcNAc-CRT at T346 to inhibit ER stress-induced cell death. Blocking T346 O-GlcNAc-CRT through CSN5 deficiency or T346A mutation resulted in Ca2+ disturbances, followed by ER stress overactivation, mitochondrial dysfunction, and ultimately cell apoptosis. Conclusion: This study reveals that CSN5-mediated aberrant O-GlcNAc-CRT acts as a crucial ER stress checkpoint, governing cell fate response to stress, and emphasizes an unrecognized role for the CSN5/CRT O-GlcNAc/ER stress axis in platinum resistance of EOC.