Pharmacological Targeting of Ferroptosis in Cancer Treatment

Mollugin suppresses proliferation and drives ferroptosis of colorectal cancer cells through inhibition of insulin-like growth factor 2 mRNA binding protein 3/glutathione peroxidase 4 axis

Increasing researches have demonstrated that targeting ferroptosis might be a new conceptual avenue to treat colorectal cancer (CRC). Mollugin is a phytochemical isolated from Rubia cordifolia L. with antitumor activity. However, whether ferroptosis mediates the antitumor activity of mollugin in CRC has not been explored. Our study aims to investigate the antitumor and pro-ferroptosis effects, and mechanisms of mollugin in CRC. We found that mollugin led to ferroptosis in CRC cells, resulting in reduced GSH level and elevated levels of ROS, Fe2+, and MDA. Mollugin treatment caused obvious decrease in cell viability and proliferation in CRC cells, which were aggravated by ferroptosis inducer erastin and attenuated by ferroptosis inhibitor ferrostatin-1. Tumor xenografts experiments proved that mollugin suppressed the tumor growth, while treatment with ferrostatin-1 attenuated the antitumor activity of mollugin in vivo. Integrated bioinformatics analysis showed that insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) was highly expressed in CRC tissues and indicated poor prognosis. Further investigation indicated that the IGF2BP3/glutathione peroxidase 4 (GPX4) axis was involved in mollugin-regulated ferroptosis in CRC. In conclusions, Mollugin suppresses proliferation and drives ferroptosis of CRC cells by inhibiting the IGF2BP3/GPX4 axis, suggesting that mollugin may be a potential therapeutic option for CRC.

Preclinical study of pachyman inducing ferroptosis against ovarian cancer: Biological targets and underlying mechanisms

Ferroptosis has gained extreme purpose in targeting cancer treatment. Poria cocos Wolf, a traditional Chinese herb, has potential anticancer properties, but the action and mechanism against ovarian cancer remain undetailed. Pachyman (Poria cocos polysaccharides) refers to the pharmacologically bioactive ingredients rich in Poria cocos. This study aimed to identify the potent actions and the network mechanisms of pachyman against ovarian cancer through preclinical analysis. Online-accessible database or platform was employed to predict candidate genes and core targets associated with ferroptosis in pachyman against ovarian cancer. Enrichment analyses were used to characterize the functional action and signaling mechanism in pachyman to treat ovarian cancer. Molecular docking imitation was conducted for verification of core target proteins. Network analysis uncovered that there were 30 mutual and 13 core genes targeting ferroptosis in pachyman and/against ovarian cancer, and additional enrichment analysis characterized that these core genes may act synergistically through multiple biological processes and molecular pathways associated with ferroptosis, including anti-inflammatory action, immunoregulation, and microenvironment modulation. The strongest affinities in core target proteins between pachyman and sarcoma (SRC), signal transducer, and activator of transcription 3 (STAT3) were further validated using molecular docking method. In conclusion, pachyman may induce antiovarian cancer potentials via regulating ferroptosis-associated biological functions and pharmacological mechanisms based on current bioinformatics findings. We reason that pachyman, the beneficial nutraceuticals, may be used clinically for future application in ovarian cancer treatment.

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.

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.

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.

Identification and Validation of a Ferroptosis-Related Long Non-Coding RNA (FRlncRNA) Signature to Predict Survival Outcomes and the Immune Microenvironment in Patients With Clear Cell Renal Cell Carcinoma

Background: The incidence of clear cell renal cell carcinoma (ccRCC) is increasing worldwide, contributing to 70–85% of kidney cancer cases. Ferroptosis is a novel type of programmed cell death and could predict prognoses in cancers. Here, we developed a ferroptosis-related long non-coding RNA (FRlncRNA) signature to improve the prognostic prediction of ccRCC.

Methods: The transcriptome profiles of FRlncRNAs and clinical data of ccRCC were obtained from The Cancer Genome Atlas and ICGC databases. Patients were randomly assigned to training cohorts, testing cohorts, and overall cohorts. The FRlncRNA signature was constructed by Lasso regression and Cox regression analysis, and Kaplan–Meier (K-M) analysis was used to access the prognosis of each group. The accuracy of this signature was evaluated by the receiver operating characteristic (ROC) curve. The visualization of functional enrichment was carried out by the gene set enrichment analysis (GSEA). Internal and external datasets were performed to verify the FRlncRNA signature.

Results: A FRlncRNA signature comprising eight lncRNAs (AL590094.1, LINC00460, LINC00944, AC024060.1, HOXB-AS4, LINC01615, EPB41L4A-DT, and LINC01550) was identified. Patients were divided into low- and high-risk groups according to the median risk score, in which the high-risk group owned a dramatical shorter survival time than that of the low-risk group. Through ROC analysis, it was found that this signature had a greater predictive capability than traditional evaluation methods. The risk score was an independent risk factor for overall survival suggested by multivariate Cox analysis (HR = 1.065, 95%CI = 1.036–1.095, and p < 0.001). We constructed a clinically predictive nomogram based on this signature and its clinical features, which is of accurate prediction about the survival rate of patients. The GSEA showed that primary pathways were the P53 signaling pathway and tumor necrosis factor–mediated signaling pathway. The major FRlncRNAs (LINC00460, LINC00944, LINC01550, and EPB41L4A-DT) were verified with the prognosis of ccRCC in the GEPIA and K-M Plotter databases. Their major target genes (BNIP3, RRM2, and GOT1) were closely related to the stage, grade, and survival outcomes of ccRCC by the validation of multiple databases. Additionally, we found two groups had a significant distinct pattern of immune function, immune checkpoint, and immune infiltration, which may lead to different survival benefits.

Conclusions: The FRlncRNA signature was accurate and act as reliable tools for predicting clinical outcomes and the immune microenvironment of patients with ccRCC, which may be molecular biomarkers and therapeutic targets.