Cashing in on ferroptosis against tumor cells: Usher in the next chapter

Resveratrol reverses drug resistance of esophageal cancer cell line Eca109/DDP via regulating ferroptosis

BACKGROUND

Resveratrol not only has anti-tumor effects, but also can enhance the chemosensitivity of tumor cells to a variety of chemotherapeutic agents. However, its effect on cisplatin sensitivity of drug-resistant esophageal cancer cells remains unclear.

AIM

To investigate whether resveratrol reverses the drug resistance of esophageal cancer Eca109/DDP cells and to explore the potential mechanism involved from the perspective of ferroptosis.

METHODS

The optimal treatment time and concentration of resveratrol and cisplatin were determined by MTT assay. Cell proliferation and the intracellular levels of malon-dialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS), and ferrous iron were detected. The protein expression of the ferroptosis-related molecules acyl coenzyme A synthetase long chain family member 4 (ACSL4), ferritin heavy chain (FTH), glutathione peroxidase 4 (GPX4), and tumor protein 53 (P53) was detected by Western blot assay.

RESULTS

MTT assay showed that compared with cisplatin alone, resveratrol combined with cisplatin significantly inhibited the growth of Eca109/DDP cells (P < 0.05). The combination of resveratrol and cisplatin not only reduced the number of colonies formed (P < 0.05), but also increased the levels of ferrous iron, MDA, and ROS (P < 0.05) and decreased the level of GSH (P < 0.05) in Eca109/DDP cells. The inhibitory effect of resveratrol on Eca109/DDP cell proliferation was partially reversed by ferrostatin-1 (Fer-1) and deferoxamine (DFO) (P < 0.05). Western blot analysis showed that compared with other groups, the protein expression of FTH and GPX4 in the resveratrol and cisplatin combination group was significantly decreased (P < 0.05), and the protein expression of ACSL4 and P53 was significantly increased (P < 0.05).

CONCLUSION

Resveratrol can inhibit cell proliferation and reverse cisplatin resistance by regulating ferroptosis in Eca109/DDP cells.

Basic mechanisms and novel potential therapeutic targets for ferroptosis in acute myeloid leukemia

Ferroptosis is a form of cell death that is regulated by iron and characterized by the buildup of lipid peroxides (LPO) and subsequent rupture of the cell membrane. The molecular mechanisms of ferroptosis involve metabolic pathways related to iron, lipids, and amino acids, which contribute to the production of lipid reactive oxygen species (ROS). In recent years, there has been increasing attention on the occurrence of ferroptosis in various diseases. Ferroptosis has been found to play a crucial role in cardiovascular diseases, digestive diseases, respiratory and immunological diseases, and particularly in malignancies. However, there is still a lack of studies on ferroptosis in acute myeloid leukemia (AML). This paper provides a comprehensive review of the mechanism of ferroptosis and its regulatory molecules and therapeutic agents in AML. It also evaluates the relationship between ferroptosis-related genes (FRGs), non-coding RNAs (ncRNAs), and prognosis to develop prognostic molecular models in AML. The study also explores the association between ferroptosis and immune infiltration in AML, to identify novel potential target regimens for AML.

Mitochondrial transfer in PC-3 cells fingerprinted in ferroptosis sensitivity: a brand new approach targeting cancer metabolism

Despite recent therapeutic advancements, cancer remains one of the leading causes of death worldwide, with mitochondrial dysfunction being associated with cancer initiation and progression, along with chemotherapeutic resistance and ferroptotic cell death failure; however, the significance of mitochondria in various cancer types remains a matter of debate for the moment. The aim of this study is to ascertain the outcome of transferring healthy mitochondria into the aggressive and rapidly proliferating prostate cancer (PC-3) cells and afterwards evaluate the efficacy of combination therapy with or without the ferroptosis inducer erastin. In this sense, normal mitochondria were first isolated from human umbilical cord-derived mesenchymal stem cells, human umbilical vein endothelial cells, and human embryonic kidney cells and were later transferred into PC-3 cells and rhodamine 6G-treated PC-3 cells exhibiting mitochondrial dysfunction. Next, cell proliferation and sensitivity to cisplatin were measured using Cell Counting Kit-8 and the Malondialdehyde Assay Lipid Peroxidation Kit, respectively, along with ferroptotic damage. Transferring the healthy mitochondria into PC-3 cells was observed to increase cell proliferation and rescue the cisplatin-induced cell death, but not the erastin-induced ferroptosis, as in mitochondrial transfer effectively enhanced erastin-mediated ferroptosis in PC-3 cells. Hence, the introduction of healthy mitochondria into the highly aggressive and proliferating cancer cells would be deemed a brand new therapeutic strategy for a variety of cancers.

Nature-Inspired Bioactive Compounds: A Promising Approach for Ferroptosis-Linked Human Diseases?

Ferroptosis is a type of cell death driven by iron overload and lipid peroxidation. It is considered a key mechanism in the development of various diseases such as atherosclerosis, Alzheimer, diabetes, cancer, and renal failure. The redox status of cells, such as the balance between intracellular oxidants (lipid peroxides, reactive oxygen species, free iron ions) and antioxidants (glutathione, glutathione Peroxidase 4), plays a major role in ferroptosis regulation and constitutes its principal biomarkers. Therefore, the induction and inhibition of ferroptosis are promising strategies for disease treatments such as cancer or neurodegenerative and cardiovascular diseases, respectively. Many drugs have been developed to exert ferroptosis-inducing and/or inhibiting reactions, such as erastin and iron-chelating compounds, respectively. In addition, many natural bioactive compounds have significantly contributed to regulating ferroptosis and ferroptosis-induced oxidative stress. Natural bioactive compounds are largely abundant in food and plants and have been for a long time, inspiring the development of various low-toxic therapeutic drugs. Currently, functional bioactive peptides are widely reported for their antioxidant properties and application in human disease treatment. The scientific evidence from biochemical and in vitro tests of these peptides strongly supports the existence of a relationship between their antioxidant properties (such as iron chelation) and ferroptosis regulation. In this review, we answer questions concerning ferroptosis milestones, its importance in physiopathology mechanisms, and its downstream regulatory mechanisms. We also address ferroptosis regulatory natural compounds as well as provide promising thoughts about bioactive peptides.

Ferroptosis-based drug delivery system as a new therapeutic opportunity for brain tumors

The brain tumor is a kind of malignant tumor with brutal treatment, high recurrence rate, and poor prognosis, and the incidence and death rate is increasing yearly. Surgery is often used to remove the primary tumor, supplemented by radiotherapy and chemotherapy, which have highly toxic side effects. Therefore, there is an urgent need to explore new strategies, methods, and technologies that can genuinely improve the treatment of brain tumors. Ferroptosis differs from traditional apoptosis's morphological and biochemical characteristics, and ferroptosis possesses its unique characteristics and mechanisms, opening up a new field of ferroptosis treatment for cancer. It has been found that there is a close relationship between ferroptosis and brain tumors, and a novel nano-drug delivery system based on ferroptosis has been used for the ferroptosis treatment of brain tumors with remarkable effects. This review firstly analyzes the characteristics of ferroptosis, summarizes the mechanism of its occurrence and some factors that can be involved in the regulation of ferroptosis, introduces the potential link between ferroptosis and brain tumors, and clarifies the feasibility of ferroptosis in the treatment of brain tumors. It then presents the ferroptosis nano drug delivery systems developed under different metabolic pathways for ferroptosis treatment of brain tumors. Finally, it summarizes the current problems and solutions of ferroptosis nano drugs for brain tumor treatment, aiming to provide a reference for developing ferroptosis nano drugs against brain tumors.

Copper-cysteamine nanoparticle-mediated microwave dynamic therapy improves cancer treatment with induction of ferroptosis

Photodynamic Therapy (PDT) holds a great promise for cancer patients, however, due to the hypoxic characteristics of most solid tumors and the limited penetration depth of light in tissues, the extensive clinical application of PDT is limited. Herein, we report microwave induced copper-cysteamine (Cu-Cy) nanoparticles-based PDT as a promising cancer treatment to overcome cancer resistance in combination with ferroptosis. The treatment efficiency of Cu-Cy-mediated microwave dynamic therapy (MWDT) tested on HCT15 colorectal cancer (CRC) cells via cell titer-blue cell viability assay and live/dead assay reveal that Cu-Cy upon MW irradiation can effectively destroy HCT15 CRC cells with average IC-50 values of 20 μg/mL. The cytotoxicity of Cu-Cy to tumor cells after MW stimulation can be alleviated by ferroptosis inhibitor. Furthermore, Cu-Cy mediated MWDT could deplete glutathione peroxide 4 (GPX4) and enhance lipid peroxides (LPO) and malondialdehyde (MDA). Our findings demonstrate that MW-activated Cu-Cy killed CRC cells by inducing ferroptosis. The superior in vivo antitumor efficacy of the Cu-Cy was corroborated by a HCT15 tumor-bearing mice model. Immunohistochemical experiments showed that the GPX4 expression level in Cu-Cy + MW group was significantly lower than that in other groups. Overall, these findings demonstrate that Cu-Cy nanoparticles have a safe and promising clinical application prospect in MWDT for deep-seated tumors and effectively inhibit tumor cell proliferation by inducing ferroptosis, which provides a potential solution for cancer resistance.

CRISPR/Cas9-mediated knockout of Lcn2 in human breast cancer cell line MDA-MB-231 ameliorates erastin-mediated ferroptosis and increases cisplatin vulnerability

AIMS

Lipocalin 2 (Lcn2) is an antioxidant-related protein upregulated in various cellular stress conditions, especially cancer. In this study, we abrogated Lcn2 expression in MDA-MB-231 breast cancer cells using the CRISPR/Cas9 technology and evaluated its effect on cellular proliferation, migration, and ferroptotic cell death.

MAIN METHODS

Validated human Lcn2 CRISPR/Cas9 knockout (KO) and homology-directed repair (HDR) plasmids were co-transfected into MDA-MB-231 breast cancer cells. Lcn2 gene knockout was confirmed at the transcriptional and protein levels using reverse transcription (RT)-PCR and enzyme-linked immunosorbent assay (ELISA). Cell proliferation was measured using Cell Counting Kit-8 (CCK-8) and colony formation assays. Cytotoxicity assay was performed in the presence or absence of erastin, cisplatin (CDDP), and ferrostatin-1 using the CCK-8 method. Ferroptosis level was measured using the malondialdehyde assay lipid peroxidation kit. The migration capacity of the cells was also evaluated using the scratch assay.

KEY FINDINGS

Targeting Lcn2 using CRISPR/Cas9 reduced cellular proliferation and migration capability, and elevated the vulnerability of MDA-MB-231 cells to cisplatin. Furthermore, Lcn2 expression loss effectively promoted erastin-mediated ferroptosis in MDA-MB-231 cells.

SIGNIFICANCE

Inhibition of Lcn2 is a potentially useful strategy for sensitizing MDA-MB-231 tumor cells to ferroptotic cell death.

Iron overload-induced ferroptosis of osteoblasts inhibits osteogenesis and promotes osteoporosis: An in vitro and in vivo study

Growing evidence indicates that iron overload is an independent risk factor for osteoporosis. However, the mechanisms are not fully understood. The purpose of our study was to determine whether iron overload could lead to ferroptosis in osteoblasts and to explore whether ferroptosis of osteoblasts is involved in iron overload-induced osteoporosis in vitro and in vivo. Ferric ammonium citrate was used to mimic iron overload conditions, while deferoxamine and ferrostatin-1 were used to inhibit ferroptosis of MC3T3-E1 cells in vitro. The ferroptosis, osteogenic differentiation and mineralization of MC3T3-E1 cells were assessed in vitro. A mouse iron overload model was established using iron dextran. Immunohistochemical analysis was performed to determine ferroptosis of osteoblasts in vivo. Enzyme-linked immunosorbent assays and calcein-alizarin red S labelling were used to assess new bone formation. Dual x-ray absorptiometry, micro-computed tomography and histopathological analysis were conducted to evaluate osteoporosis. The results showed that iron overload reduced cell viability, superoxide dismutase and glutathione levels, increased reactive oxygen species generation, lipid peroxidation, malondialdehyde levels and ferroptosis-related protein expression, and induced ultrastructural changes in mitochondria. Iron overload could also inhibit osteogenic differentiation and mineralization in vitro. Inhibiting ferroptosis reversed the changes described above. Iron overload inhibited osteogenesis, promoted the ferroptosis of osteoblasts and induced osteoporosis in vivo, which could also be improved by deferoxamine and ferrostatin-1. These results demonstrate that ferroptosis of osteoblasts plays a crucial role in iron overload-induced osteoporosis. Maintaining iron homeostasis and targeting ferroptosis of osteoblasts might be potential measures of treating or preventing iron overload-induced osteoporosis.

Plumping up a Cushion of Human Biowaste in Regenerative Medicine: Novel Insights into a State-of-the-Art Reserve Arsenal

Major breakthroughs and disruptive methods in disease treatment today owe their thanks to our inch by inch developing conception of the infinitive aspects of medicine since the very beginning, among which, the role of the regenerative medicine can on no account be denied, a branch of medicine dedicated to either repairing or replacing the injured or diseased cells, organs, and tissues. A novel means to accomplish such a quest is what is being called “medical biowaste”, a large assortment of biological samples produced during a surgery session or as a result of physiological conditions and biological activities. The current paper accentuating several of a number of promising sources of biowaste together with their plausible applications in routine clinical practices and the confronting challenges aims at inspiring research on the existing gap between clinical and basic science to further extend our knowledge and understanding concerning the potential applications of medical biowaste.

Non-coding RNAs in ferroptotic cancer cell death pathway: meet the new masters

Despite the recent advances in cancer therapy, cancer chemoresistance looms large along with radioresistance, a major challenge in dire need of thorough and minute investigation. Not long ago, cancer cells were reported to have proven refractory to the ferroptotic cell death, a newly discovered form of regulated cell death (RCD), conspicuous enough to draw attention from scholars in terms of targeting ferroptosis as a prospective therapeutic strategy. However, our knowledge concerning the underlying molecular mechanisms through which cancer cells gain immunity against ferroptosis is still in its infancy. Of late, the implication of non-coding RNAs (ncRNAs), including circular RNAs (circRNAs), microRNAs (miRNAs), and long non-coding RNAs (lncRNAs) in ferroptosis has been disclosed. Nevertheless, precisely explaining the molecular mechanisms behind the contribution of ncRNAs to cancer radio/chemotherapy resistance remains a challenge, requiring further clarification. In this review, we have presented the latest available information on the ways and means of regulating ferroptosis by ncRNAs. Moreover, we have provided important insights about targeting ncRNAs implicated in ferroptosis with the hope of opening up new horizons for overcoming cancer treatment modalities. Though a long path awaits until we make this ambitious dream come true, recent progress in gene therapy, including gene-editing technology will aid us to be optimistic that ncRNAs-based ferroptosis targeting would soon be on stream as a novel therapeutic strategy for treating cancer.

Pharmacological Targeting of Ferroptosis in Cancer Treatment

Ferroptosis is a non-apoptotic mode of Regulated Cell Death (RCD) driven by excessive accumulation of toxic lipid peroxides and iron overload. Ferroptosis could be triggered by inhibiting the antioxidant defense system and accumulating iron-dependent Reactive Oxygen Species (ROS) that react with polyunsaturated fatty acids in abundance. Emerging evidence over the past few years has revealed that ferroptosis is of great potential in inhibiting growth and metastasis and overcoming tumor cell resistance. Thus, targeting this form of cell death could be perceived as a potentially burgeoning approach in cancer treatment. This review briefly presents the underlying mechanisms of ferroptosis and further aims to discuss various types of existing drugs and natural compounds that could be potentially repurposed for targeting ferroptosis in tumor cells. This, in turn, will provide critical perspectives on future studies concerning ferroptosis-based cancer therapy.