A novel sesquiterpene lactone fraction from Eupatorium chinense L. suppresses hepatocellular carcinoma growth by triggering ferritinophagy and mitochondrial damage

Targeting regulated cell death (RCD) with naturally derived sesquiterpene lactones in cancer therapy

Regulated cell death (RCD) is a type of cell death modulated by specific signal transduction pathways. Currently, known RCD types include apoptosis, autophagy, ferroptosis, necroptosis, cuproptosis, pyroptosis, and NETosis. Mutations in cancer cells may prevent the RCD pathway; therefore, targeting RCD in tumors has become a promising therapeutic approach. Sesquiterpene lactones represent a diverse and extensive class of plant-derived phytochemicals that serve as potential sources for developing various drugs. Recent studies have shown that sesquiterpene lactones have promising potential in cancer treatment. This review systematically summarizes recent progress in the study of sesquiterpene lactones as antitumor agents, highlighting their role in targeting various RCD pathways, including those involved in apoptosis, autophagy, ferroptosis, necroptosis, and cuproptosis. The primary purpose of the present review is to provide a clear picture of the regulation of RCD by sesquiterpene lactones against different targets in various cancers, which will facilitate the development of new strategies for cancer therapy.

Targeting Hepatocellular Carcinoma: Schisandrin A Triggers Mitochondrial Disruption and Ferroptosis

The main focus of this research was to examine SchA's role in the hepatocellular carcinoma (HCC) development. LO2 and Huh7 cell viability were assessed using the MTT assay. The experiments included flow cytometry, colony formation, transwell, wound healing, and immunofluorescence assays to evaluate apoptosis levels, cells colony-forming ability, ROS levels, invasion and migration ability, and mitochondrial membrane potential. Biochemical kits was utilized for checking the ATP, mitochondrial DNA, MDA, GSH, and Fe2+ levels in the Huh7 cells, and western blot for measuring the ferroptosis and AMPK/mTOR related-protein expression levels. The MTT assay demonstrated that SchA significantly reduced the vitality of Huh7 cells ranging from 10 to 50 μM, whereas it exhibited no discernible impact on LO2 cells. Additionally, SchA significantly inhibited colony-forming ability, invasion ability, and migration ability within the concentration range of 10 to 50 μM, with a reduction of 68% in colony formation at 50 μM. SchA also induced apoptosis in a dose-dependent manner. Moreover, SchA was observed to significantly elevate ROS levels dose-dependently, down-regulate mitochondrial membrane potential (JC-1) at 20 and 50 μM, and reduce the levels of ATP and mtDNA dose-dependently. Various concentrations of SchA resulted in a notable elevation in MDA and Fe2+ levels as well as ACSL4 protein expression, accompanied by a reduction in GSH level and the protein expression of GPX4 and SLC7A11. Furthermore, SchA induced the activation of the AMPK/mTOR pathway in Huh7 cells, as evidenced by the increased phosphorylation level of AMPK and decreased phosphorylation level of mTOR. SchA might inhibit the progress of HCC through mitochondrial ferroptosis and dysfunction mediated by AMPK/mTOR pathway.

Dihydroartemisinin-driven TOM70 inhibition leads to mitochondrial destabilization to induce pyroptosis against lung cancer

Enhancement of malignant cell immunogenicity to relieve immunosuppression of lung cancer microenvironment is essential in lung cancer treatment. In previous study, we have demonstrated that dihydroartemisinin (DHA), a kind of phytopharmaceutical, is effective in inhibiting lung cancer cells and boosting their immunogenicity, while the initial target of DHA's intracellular action is poorly understood. The present in-depth analysis aims to reveal the influence of DHA on the highly expressed TOM70 in the mitochondrial membrane of lung cancer. The affinity of DHA and TOM70 was analyzed by microscale thermophoresis (MST), pronase stability, and thermal stability. The functions and underlying mechanism were investigated using western blots, qRT-PCR, flow cytometry, and rescue experiments. TOM70 inhibition resulted in mtDNA damage and translocation to the cytoplasm from mitochondria due to the disruption of mitochondrial homeostasis. Further ex and in vivo findings also showed that the cGAS/STING/NLRP3 signaling pathway was activated by mtDNA and thereby malignant cells underwent pyroptosis, leading to enhanced immunogenicity of lung cancer cells in the presence of DHA. Nevertheless, DHA-induced mtDNA translocation and cGAS/STING/NLRP3 mobilization were synchronously attenuated when TOM70 was replenished. Finally, DHA was demonstrated to possess potent anti-lung cancer efficacy in vitro and in vivo. Taken together, these data confirm that TOM70 is an important target for DHA to disturb mitochondria homeostasis, which further activates STING and arouses pyroptosis to strengthen immunogenicity against lung cancer thereupon. The present study provides vital clues for phytomedicine-mediated anti-tumor therapy.

Novel Withanolides from Tubocapsicum anomalum Suppress Triple-Negative Breast Cancer by Triggering Apoptosis and p53-ASCT2-SLC7A11-Mediated Ferroptosis

Triple-negative breast cancer (TNBC) is a malignant breast cancer. There is an urgent need for effective drugs to be developed for TNBC. Tubocapsicum anomalum (T. anomalum) has been reported to have an anti-tumor effect, and six novel withanolides were isolated from it and designated as TAMEWs. However, its anti-TNBC effect is still unknown. The results of an MTT assay indicated a higher sensitivity of TNBC cells to TAMEWs compared to other cells. TAMEWs induced apoptosis via mitochondrial dysfunction. They caused increased levels of lipid ROS and Fe2+, with downregulation of GSH and cystine uptake, and it has been confirmed that TAMEWs induced ferroptosis. Additionally, the results of Western blotting indicate that TAMEWs significantly decrease the expressions of ferroptosis-related proteins. Through further investigation, it was found that the knockdown of the p53 gene resulted in a significant reversal of ferroptosis and the expressions of its associated proteins SLC7A11, ASCT2, and GPX4. In vivo, TAMEWs suppressed TNBC growth with no obvious damage. The IHC results also showed that TAMEWs induced apoptosis and ferroptosis in vivo. Our findings provide the first evidence that TAMEWs suppress TNBC growth through apoptosis and ferroptosis.

Natural products targeting macroautophagy signaling in hepatocellular carcinoma therapy: Recent evidence and perspectives

Hepatocellular carcinoma (HCC), presently the second leading cause of global cancer-related mortality, continues to pose significant challenges in the realm of medical oncology, impacting both clinical drug selection and mechanistic research. Recent investigations have unveiled autophagy-related signaling as a promising avenue for HCC treatment. A growing body of research has highlighted the pivotal role of autophagy-modulating natural products in inhibiting HCC progression. In this context, we provide a concise overview of the fundamental autophagy mechanism and delineate the involvement of autophagic signaling pathways in HCC development. Additionally, we review pertinent studies demonstrating how natural products regulate autophagy to mitigate HCC. Our findings indicate that natural products exhibit cytotoxic effects through the induction of excessive autophagy, simultaneously impeding HCC cell proliferation by autophagy inhibition, thereby depriving HCC cells of essential energy. These effects have been associated with various signaling pathways, including PI3K/AKT, MAPK, AMPK, Wnt/β-catenin, Beclin-1, and ferroautophagy. These results underscore the considerable therapeutic potential of natural products in HCC treatment. However, it is important to note that the present study did not establish definitive thresholds for autophagy induction or inhibition by natural products. Further research in this domain is imperative to gain comprehensive insights into the dual role of autophagy, equipping us with a better understanding of this double-edged sword in HCC management.

Ferroptosis: Potential opportunities for natural products in cancer therapy

Cancer cells often exhibit defects in the execution of cell death, resulting in poor clinical outcomes for patients with many cancer types. Ferroptosis is a newly discovered form of programmed cell death characterized by intracellular iron overload and lipid peroxidation in the cell membrane. Increasing evidence suggests that ferroptosis is closely associated with a wide variety of physiological and pathological processes, particularly in cancer. Notably, various bioactive natural products have been shown to induce the initiation and execution of ferroptosis in cancer cells, thereby exerting anticancer effects. In this review, we summarize the core regulatory mechanisms of ferroptosis and the multifaceted roles of ferroptosis in cancer. Importantly, we focus on natural products that regulate ferroptosis in cancer cells, such as terpenoids, polyphenols, alkaloids, steroids, quinones, and polysaccharides. The clinical efficacy, adverse effects, and drug-drug interactions of these natural products need to be evaluated in further high-quality studies to accelerate their application in cancer treatment.

Natural product-derived ferroptosis mediators

It has been 11 years since ferroptosis, a new mode of programmed cell death, was first proposed. Natural products are an important source of drug discovery. In the past five years, natural product-derived ferroptosis regulators have been discovered in an endless stream. Herein, 178 natural products discovered so far to trigger or resist ferroptosis are classified into 6 structural classes based on skeleton type, and the mechanisms of action that have been reported are elaborated upon. If pharmacodynamic data are sufficient, the structure and bioactivity relationship is also presented. This review will provide medicinal chemists with some effective ferroptosis regulators, which will promote the research of natural product-based treatment of ferroptosis-related diseases in the future.

Ferritinophagy: research advance and clinical significance in cancers

Ferritinophagy, a process involving selective autophagy of ferritin facilitated by nuclear receptor coactivator 4 (NCOA4), entails the recognition of ferritin by NCOA4 and subsequent delivery to the autophagosome. Within the autophagosome, ferritin undergoes degradation, leading to the release of iron in the lysosome. It is worth noting that excessive iron levels can trigger cell death. Recent evidence has elucidated the significant roles played by ferritinophagy and ferroptosis in regulation the initiation and progression of cancer. Given the crucial role of ferritinophagy in tumor biology, it may serve as a potential target for future anti-tumor therapeutic interventions. In this study, we have provided the distinctive features of ferritinophagy and its distinctions from ferroptosis. Moreover, we have briefly examined the fundamental regulatory mechanisms of ferritinophagy, encompassing the involvement of the specific receptor NCOA4, the Nrf2/HO-1 signaling and other pathways. Subsequently, we have synthesized the current understanding of the impact of ferritinophagy on cancer progression and its potential therapeutic applications, with a particular emphasis on the utilization of chemotherapy, nanomaterials, and immunotherapy to target the ferritinophagy pathway for anti-tumor purposes.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.