Understanding sorafenib-induced ferroptosis and resistance mechanisms: Implications for cancer therapy

Salinomycin inhibits SREBP1 to sensitize ferroptosis and ameliorate sorafenib resistance in clear cell renal cell carcinoma

Backgrounds Resistance to sorafenib, a frontline therapy for advanced ccRCC, is associated with decreased sensitivity to ferroptosis. Our research focuses on elucidating the mechanisms underlying ccRCC's resistance to sorafenib-induced ferroptosis and identifying potential new agents that could overcome this resistance.

METHODS

The silencing of SREBP1 was employed to evaluate the role of this key transcription factor in lipid synthesis and its contribution to ferroptosis resistance in sorafenib-treated ccRCC cells. The ATF4-mediated induction of SREBP1 following salinomycin treatment was assessed by western blot, RT-PCR, immunohistochemistry, chromatin immunoprecipitation, and dual-luciferase reporter assays. In cultured ccRCC cells, the combined effects of salinomycin and sorafenib on ferroptosis induction were evaluated by assessing cell viability, glutathione levels, malondialdehyde levels, BODIPY fluorescence, and intracellular Fe2+ concentration. In an orthotopic ccRCC mouse model, the synergistic effects of salinomycin and sorafenib on both ferroptosis and tumor progression were examined.

RESULTS

Overexpression of SREBP1 was observed in ccRCC tumor tissue, and induced by sorafenib treatment. Silencing SREBP1 reduced the resistance of ccRCC cells to ferroptosis induced by sorafenib. Salinomycin decreased ATF4 level, which in turn inhibited SREBP1 transcription. Treatment with salinomycin enhanced the sensitivity of ccRCC cells to sorafenib-induced ferroptosis. In the orthotopic xenograft mouse model of ccRCC, the combination of salinomycin and sorafenib showed a synergistic effect in inducing ferroptosis inhibiting tumor growth.

CONCLUSIONS

Salinomycin treatment mitigates resistance to sorafenib-induced ferroptosis by inhibiting SREBP1. The combination of salinomycin and sorafenib synergistically enhances ferroptosis and suppresses ccRCC growth.

USP22 promotes the proliferation and Sorafenib resistance of hepatocellular carcinoma cells via its deubiquitinase activity

BACKGROUND

Hepatocellular carcinoma remains one of the most lethal cancers, characterized by poor prognosis and low life expectancy. Unfortunately, there are very few molecular therapeutic options available for it. Sorafenib is a current standard first-line treatment for advanced hepatocellular carcinoma, however, drug resistance significantly limits its therapeutic efficacy.

METHODS

Ubiquitin-specific protease 22 (USP22) expression level and its prognostic significance in hepatocellular carcinoma were analyzed using The Cancer Genome Atlas (TCGA) database. A series of cellular experiments related to cell proliferation and ferroptosis, and mouse tumor-bearing experiments were performed to investigate the role of USP22 in hepatocellular carcinoma cell growth and Sorafenib resistance. Flag affinity purification coupled with mass spectrometry, co-immunoprecipitation, and ubiquitination assays were conducted to identify direct substrates of USP22. Spike-in chromatin-immunoprecipitation (ChIP)-seq, RNA-seq, and ChIP assays were employed to explore the transcriptional substrates of USP22 as an H2BK120ub deubiquitinase.

RESULTS

Analysis of TCGA database reveals that USP22 is highly expressed in hepatocellular carcinoma tissues, which is closely associated with poor patient prognosis. Our data further indicates that USP22 promotes the proliferation of hepatocellular carcinoma cells via deubiquitinating and stabilizing cyclin-dependent kinase 11B (CDK11B). Additionally, USP22 acts as a novel inducer of Sorafenib resistance and suppresses Sorafenib-triggered ferroptosis in hepatocellular carcinoma cells. It reduces the transcription of transferrin receptor (TFRC) by decreasing H2BK120ub occupancy at TFRC transcription start site (TSS) downstream region, thereby inhibiting ferroptosis upon Sorafenib treatment. Finally, animal experiments confirm the role of USP22 in promoting hepatocellular carcinoma cell growth and Sorafenib resistance in vivo. Taken together, this study demonstrates that USP22 promotes hepatocellular carcinoma growth and inhibits Sorafenib-induced ferroptosis by deubiquitinating non-histone substrate CDK11B and histone H2B, respectively.

CONCLUSIONS

Our findings suggest USP22 as a promising prognostic biomarker and therapeutic target for hepatocellular carcinoma patients, particularly those with Sorafenib resistance.

KEY POINTS

USP22 promotes the proliferation of hepatocellular carcinoma cells by deubiquitinating and stabilizing cyclin-dependent kinase CDK11B. USP22 enhances Sorafenib resistance of hepatocellular carcinoma cells by inhibiting ferroptosis through the USP22/H2BK120ub/TFRC axis.

New nicotinamide-thiadiazol hybrids as VEGFR-2 inhibitors for breast cancer therapy: design, synthesis and in silico and in vitro evaluation

Vascular endothelial growth factor receptor-2 (VEGFR-2) is a key regulator of tumor angiogenesis and has become an important target in anticancer drug development. In this study, novel nicotinamide-thiadiazol hybrids were synthesized and evaluated for their anti-breast cancer potential through VEGFR-2 inhibition. The compounds were assessed in vitro for their cytotoxicity against MDA-MB-231 and MCF-7 cell lines. Among the nicotinamide-thiadiazol hybrids, 7a exhibited the most potent anticancer activity, with IC50 values of 4.64 ± 0.3 μM in MDA-MB-231 and 7.09 ± 0.5 μM in MCF-7, showing comparable efficacy to sorafenib. VEGFR-2 inhibition assays confirmed strong inhibitory potential with an IC50 of 0.095 ± 0.05 μM. In vitro cell cycle analysis indicated that 7a induced S-phase arrest, while apoptosis assays demonstrated a substantial increase in late apoptotic cells (44.01%). Other in vitro mechanistic studies further confirmed the activation of the intrinsic apoptotic pathway, as evidenced by caspase-3 activation (8.2-fold), Bax upregulation (6.9-fold), and Bcl-2 downregulation (3.68-fold). Computational studies, including molecular docking and 200 ns molecular dynamics (MD) simulations, confirmed the stable interaction of 7a with VEGFR-2, showing binding affinities comparable to sorafenib. Further validation through MM-GBSA, ProLIF, PCAT, and FEL analyses reinforced its strong binding capability. Additionally, ADMET predictions suggested favorable pharmacokinetic properties, including good absorption, high plasma protein binding, and non-CYP2D6 inhibition. Moreover, toxicity analysis classified 7a as non-mutagenic and non-carcinogenic, with a lower predicted toxicity than sorafenib. Finally, density functional theory (DFT) calculations highlighted the structural stability and reactivity of 7a, further supporting its potential as a VEGFR-2 inhibitor. These findings suggest that 7a is a promising VEGFR-2 inhibitor with significant anticancer potential, favorable pharmacokinetics, and an improved safety profile. Further preclinical studies and structural modifications are warranted to optimize its therapeutic potential.

C12ORF49 inhibits ferroptosis in hepatocellular carcinoma cells via reprogramming SREBP1/SCD1-mediated lipid metabolism

Altered lipid metabolism is an emerging hallmark of cancer, which is involved in various aspects of the cancer phenotypes. C12ORF49 has recently been identified as a pivotal regulator of sterol regulatory element binding proteins (SREBPs), a family of transcriptional factors that govern lipid biosynthesis. Nevertheless, the function of C12ORF49 in human cancers has not been studied. Here, we show that C12ORF49 levels are higher in HCC tissue than in nearby non-cancerous liver tissue. Additionally, increased C12ORF49 expression is linked to poorer survival outcomes in HCC patients. Functional experiments uncovered that knockdown of C12ORF49 inhibited HCC cell survival and tumor growth by inducing ferroptosis, whereas the opposites were observed upon C12ORF49 overexpression. Mechanistically, C12ORF49 promotes SREBP1/SCD-regulated production of monounsaturated fatty acids, which inhibits ferroptosis in HCC cells. Furthermore, silencing C12ORF49 combined with Sorafenib treatment showed a synergistic effect in inducing HCC cell death. Together, our findings suggest a critical role of C12ORF49 in the evasion of ferroptosis in HCC cells, highlighting the potential of targeting C12ORF49 as a therapeutic strategy to enhance the efficacy of Sorafenib treatment in HCC.

ARL8B regulates lysosomal function and predicts poor prognosis in hepatocellular carcinoma

Adenosine 5'-diphosphate ribosylation factor-like 8B (ARL8B), a small GTPase, is involved in lysosome motility. Our study investigates the role of ARL8B in hepatocellular carcinoma (HCC) using in vitro and in vivo experiments, bioinformatics, and clinical data. We found that ARL8B expression is abnormally elevated in HCC and correlates with poor prognosis. ARL8B knockdown triggered lysosomal dysfunction-manifesting as abnormal morphology, decreased pH, reduced hydrolase activity, and impaired autophagic degradation-which subsequently led to cell cycle arrest and reduced cell viability. Additionally, tumors with high ARL8B expression (ARL8Bhigh) exhibited notable differences in tumor microenvironment composition compared to those with low ARL8B expression (ARL8Blow). ARL8Bhigh HCCs had significantly increased infiltration of NFKBIZ+/HIF1A+ and VEGFA+/SPP1+ neutrophils. EcoTyper analysis indicated that ARL8Bhigh HCCs had a lower proportion of carcinoma ecotype 6, a cellular ecosystem common in normal tissues but rare in tumors. Bioinformatics and real-world analysis showed a positive correlation between ARL8B and PD-L1 expression. Patients with high ARL8B expression exhibited increased sensitivity to sorafenib and immune checkpoint blockade therapy. In conclusion, our findings identify ARL8B as a key lysosomal regulator associated with tumor microenvironment composition in HCC, suggesting its potential as both a therapeutic target and a biomarker for predicting treatment response.

Ferroptosis enhances the therapeutic potential of oncolytic adenoviruses KD01 against cancer

Oncolytic virotherapy has emerged as a promising strategy for cancer treatment by selectively targeting and lysing tumor cells. However, its efficacy is often limited in certain tumor types due to multiple factors. This study explores the combination of oncolytic adenoviruses with Erastin, a potent ferroptosis inducer, to enhance antitumor efficacy in oncolytic virus-insensitive cancer cell lines. In vitro experiments demonstrated that Erastin significantly increased the cytotoxicity of oncolytic virotherapy, leading to greater inhibition of cell proliferation and elevated rates of cell death compared to monotherapies. The combination treatment further promoted ferroptosis, as evidenced by increased reactive oxygen species (ROS) levels, enhanced lipid peroxidation, and disrupted redox homeostasis. RNA sequencing identified the downregulation of Dickkopf-1 (DKK1) as a key mediator of the enhanced ferroptotic effect. Restoring the expression of DKK1 partially mitigated the cytotoxic effects of the combination therapy, highlighting its crucial role in mediating the enhanced ferroptosis-induced oncolytic virotherapy efficacy. In vivo studies further validated these findings, demonstrating that the combined treatment significantly reduced tumor growth without inducing notable toxicity. This novel therapeutic approach has great potential to enhance the efficacy of oncolytic virotherapy in cancers resistant to oncolytic viruses by inducing ferroptosis. Further investigation in clinically relevant models is warranted to fully elucidate the underlying mechanisms and to optimize this combination strategy for potential clinical applications.

Exploring the potential mechanisms of sorafenib resistance in hepatocellular carcinoma cell lines based on RNA sequencing

BACKGROUND

Exploring the mechanisms underlying sorafenib resistance that arises in hepatocellular carcinoma (HCC) may provide new treatment perspectives.

METHODS

Drug-resistant and drug-sensitive HCC cell lines were constructed from existing HepG2 and Huh7 cell lines, and gene expression profiles were determined. Genes differentially expressed between the resistant and sensitive lines were identified and organized into modules based on weighted gene co-expression network analysis. Pathways and biological processes involving the module genes were explored and validated using gene set enrichment analysis. By analyzing the expression differences of Long non-coding ribonucleic acid (RNAs), microRNAs (miR), circular RNAs, and messenger RNAs between drug-resistant and sensitive cell lines, a gene regulatory network was constructed to reveal the mechanism of sorafenib resistance. In addition, we also analyzed the correlation between the candidate sorafenib resistance gene and the survival of patients with liver cancer.

RESULTS

Our analyses suggested that sorafenib resistance could arise when the circular RNA circ_SPECC1 regulated the microRNA hsa-let-7c-5p, which in turn regulated the cell cycle proteins cyclin-dependent kinase 1 and polo-like kinase 1, as well as interleukin 13 receptor, alpha 1 in the Janus kinase-signal transducer (JAK-STAT) and activator of transcription signaling pathway. Patient survival was associated with miR-18a-z and mitogen-activated protein kinase kinase 4 levels.

CONCLUSIONS

Sorafenib resistance in HCC may involve the circ_SPECC1, hsa-let-7c-5p, cell cycle, and JAK-STAT signaling pathways. These insights may guide future efforts to mitigate or prevent such resistance.

Harnessing nanoparticles for reshaping tumor immune microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers, characterized by high morbidity and mortality rates. Recently, immunotherapy has emerged as a crucial treatment modality for HCC, following surgery, locoregional therapies, and targeted therapies. This approach harnesses the body's immune system to target and eliminate cancer cells, potentially resulting in durable antitumor responses. However, acquired resistance and the tumor immunosuppressive microenvironment (TIME) significantly hinder its clinical application. Recently, advancements in nanotechnology, coupled with a deeper understanding of cancer biology and nano-biological interactions, have led to the development of various nanoparticles aimed at enhancing therapeutic efficacy through specific targeting of tumor tissues. These nanoparticles increase the accumulation of immunotherapeutic drugs within the tumor microenvironment, thereby transforming the TIME. In this review, we provide a concise overview of the fundamental principles governing the TIME landscape in HCC and discuss the rationale for and applications of nanoparticles in this context. Additionally, we highlight existing challenges and potential opportunities for the clinical translation of cancer nanomedicines.

Pifithrin-μ sensitizes mTOR-activated liver cancer to sorafenib treatment

TSC2, a suppressor of mTOR, is inactivated in up to 20% of HBV-associated liver cancer. This subtype of liver cancer is associated with aggressive behavior and early recurrence after hepatectomy. Being the first targeted regimen for advanced liver cancer, sorafenib has limited efficacy in HBV-positive patients. In this study, we observed that mTOR-activated cells, due to the loss of either TSC2 or PTEN, were insensitive to the treatment of sorafenib. Mechanistically, HSP70 enhanced the interaction between active mTOR-potentiated CREB1 and CREBBP to boost the transcription of the antioxidant response regulator SESN3. In return, elevated SESN3 enhanced cellular antioxidant capacity and rendered cells resistant to sorafenib. Pifithrin-μ, an HSP70 inhibitor, synergized with sorafenib in the induction of ferroptosis in mTOR-activated liver cancer cells and suppression of TSC2-deficient hepatocarcinogenesis. Our findings highlight the pivotal role of the mTOR-CREB1-SESN3 axis in sorafenib resistance of liver cancer and pave the way for combining pifithrin-μ and sorafenib for the treatment of mTOR-activated liver cancer.

Oxygen-boosted fluorinated prodrug hybrid nanoassemblies for bidirectional amplification of breast cancer ferroptosis

Ferroptosis, a novel form of cell death, has emerged as a promising approach in cancer therapy. However, the single ferroptosis inducer was ineffective, and the induction of ferroptosis was severely limited by hypoxia niches in breast cancer. Herein, we develop a disulfide bond-bridging fluorinated doxorubicin (DOX) prodrug, which can facilitate the formation of hybrid nanoassemblies (NAs) with sorafenib (Sor) through a molecular co-assembly strategy. The incorporation of fluorinated side chains enhances the oxygen-carrying capacity of the NAs, successfully reversing the redox offensive and defensive situation caused by the dilemma of hypoxia. The reactive oxygen species (ROS) generation capacity of DOX via nicotinamide adenine dinucleotide oxidase (NOXs) within hypoxic tumors is significantly enhanced due to the presence of fluorinated oxygen-carrying as a catalytic substrate. Furthermore, the depletion of nicotinamide adenine dinucleotide phosphate (NADPH) significantly impairs the synthesis of glutathione (GSH), which collaboratively inhibits GSH production with Sor. As expected, the NAs with bidirectional amplification of ROS production and GSH inhibition displays potent antitumor activity in 4 T1 breast cancer-bearing mice. Together, this study presents a novel nanotherapeutic approach for ferroptosis-driven tumor therapy.

METTL14 decreases FTH1 mRNA stability via m6A methylation to promote sorafenib-induced ferroptosis of cervical cancer

Cervical cancer (CC) is a prevalent malignancy among women worldwide. This study was designed to investigate the role of METTL14 in sorafenib-induced ferroptosis in CC. METTL14 expression and m6A methylation were determined in CC tissues, followed by analyzes correlating these factors with clinical features. Subsequently, METTL14 was knocked down in CC cell lines, and the effects on cell proliferation, mitochondrial morphology and ferroptosis were assessed using CCK-8, microscopy, and markers associated with ferroptosis, respectively. The regulatory relationship between METTL14 and FTH1 was verified using qRT-PCR and luciferase reporter assays. The functional significance of this interaction was further investigated both in vitro and in vivo by co-transfecting cells with overexpression vectors or shRNAs targeting METTL14 and FTH1 after sorafenib treatment. METTL14 expression and m6A methylation were significantly reduced in CC tissues, and lower METTL14 expression levels were associated with a poorer CC patients' prognosis. Notably, METTL14 expression increased during sorafenib-induced ferroptosis, and METTL14 knockdown attenuated the ferroptotic response induced by sorafenib in CC cells. FTH1 was identified as a direct target of METTL14, with METTL14 overexpression leading to increased m6A methylation of FTH1 mRNA, resulting in reduced stability and expression of FTH1 in CC. Furthermore, FTH1 overexpression or treatment with LY294002 partially counteracted the promotion of sorafenib-induced ferroptosis by METTL14. In vivo xenograft experiments demonstrated that inhibiting METTL14 reduced the anticancer effects of sorafenib, whereas suppression of FTH1 significantly enhanced sorafenib-induced ferroptosis and increased its anticancer efficacy. METTL14 reduces FTH1 mRNA stability through m6A methylation, thereby enhancing sorafenib-induced ferroptosis, which contributes to suppressing CC progression via the PI3K/Akt signaling pathway.

Resveratrol liposomes reverse sorafenib resistance in renal cell carcinoma models by modulating PI3K-AKT-mTOR and VHL-HIF signaling pathways

RCC is a malignant tumor arising from the urothelium of renal parenchyma that remains challenging to be treated. In this study, we assessed the anti-tumor effects of Resveratrol liposomes (RES-lips) combined with sorafenib on renal cell carcinoma (RCC) and explored the potential mechanisms underlying the improvement of sorafenib resistance models. Tumor growth and survival following treatment with sorafenib alone or in combination with RES-lips was evaluated in a RCC xenograft mouse model. Flow cytometry results demonstrated that the combination of RES-lips and sorafenib significantly enhanced the G1/S phase arrest of sorafenib-resistant cells. When compared with the PBS or monotherapy groups, treatment with RES-lips combined with sorafenib exhibited significant inhibition of tumor growth in the RCC xenograft mouse model with tumor growth inhibition (TGI) rates and complete remission (CR) rates of 90.1 % and 50 %, respectively. Concersely, the maximum TGI rate was 53.6 % in the RES-lips monoherapy group and 29.2 % and in the sorafenib monotherapy group, and no animals achieved CR. Additionally, the current combination therapy promoted the proliferation of unactivated splenic lymphocytes and the proliferation of soybean protein A- and lipopolysaccharide-stimulated lymphocytes compared with PBS or monotherapy treatments. Further western blotting analysis suggested that RES-lips may enhance the resistance of RCC to sorafenib by inhibiting PI3K-AKT-mTOR and VHL-HIF signaling pathways, ultimately augmenting the tumor growth inhibition effect of the combination therapy. RES-lips may improve the sorafenib resistance in RCC, and the underlying mechanism may be related to the regulation of PI3K-AKT-mTOR and VHL-HIF signaling pathways.

Therapeutic efficacy of ferroptosis in the treatment of colorectal cancer (Review)

Colorectal cancer (CRC) is the third most common malignancy worldwide, and the second leading cause of cancer-associated mortality. The incidence and mortality rates of CRC remain high, posing a significant threat to humans and overall quality of life. Current therapeutic strategies, such as surgery and chemotherapy, are limited due to disease recurrence, chemotherapeutic drug resistance and toxicity. Thus, research is focused on the development of novel treatment approaches. In 2012, ferroptosis was identified as a form of regulated cell death that is iron-dependent and driven by lipid peroxidation. Notably, therapies targeting ferroptosis exhibit potential in the treatment of disease; however, their role in CRC treatment remains controversial. The present study aimed to systematically review the mechanisms and signaling pathways of ferroptosis in CRC, and the specific role within the tumor microenvironment. Moreover, the present study aimed to review the role of ferroptosis in drug resistance, offering novel perspectives for the diagnosis and treatment of CRC.

Targeting Hepatic Cancer Stem Cells (CSCs) and Related Drug Resistance by Small Interfering RNA (siRNA)

Tumor recurrence after curative therapy and hepatocellular carcinoma (HCC) cells' resistance to conventional therapies is the reasons for the worse clinical results of HCC patients. A tiny population of cancer cells with a strong potential for self-renewal, differentiation, and tumorigenesis has been identified as cancer stem cells (CSCs). The discovery of CSC surface markers and the separation of CSC subpopulations from HCC cells have been made possible by recent developments in the study of hepatic (liver) CSCs. Hepatic CSC surface markers include epithelial cell adhesion molecules (EpCAM), CD133, CD90, CD13, CD44, OV-6, ALDH, and K19. CSCs have a significant influence on the development of cancer, invasiveness, self-renewal, metastasis, and drug resistance in HCC, and thus provide a therapeutic chance to treat HCC and avoid its recurrence. Therefore, it is essential to develop treatment approaches that specifically and effectively target hepatic stem cells. Given this, one potential treatment approach is to use particular small interfering RNA (siRNA) to target CSC, disrupting their behavior and microenvironment as well as changing their epigenetic state. The characteristics of CSCs in HCC are outlined in this study, along with new treatment approaches based on siRNA that may be used to target hepatic CSCs and overcome HCC resistance to traditional therapies.

Sorafenib-induced macrophage extracellular traps via ARHGDIG/IL4/PADI4 axis confer drug resistance through inhibiting ferroptosis in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common as well as leading causes of mortality worldwide, and sorafenib is the first-line treatment in HCC patients. Unfortunately, drug resistance to sorafenib often develops. However, the underlying mechanism remains unclear. Here, we reveal the important role of macrophage extracellular traps (METs)-mediated crosstalk between macrophages and tumor cells in sorafenib resistance.

METHODS

METs in HCC tumor tissues were detected using immunofluorescence. The concentrations of MPO-DNA, elastase and cytokines were measured using ELISA. The mRNA expression levels of genes were confirmed by qRT-PCR. The siRNAs were conducted to knock ARHGDIG in Hepa1-6 and Hep3B cells. Western Blot assay was performed to determine protein expression of Rho GDP dissociation inhibitor gamma (ARHGDIG, or RHOGDI-3), PADI2, and PADI4. Cell viability and migration were evaluated by CCK-8 assay and transwell assay, respectively. Cell ferroptosis was assessed by measurement of Fe2+ concentration, flow cytometry assay of lipid ROS, and western blot assay of GPX4. The functions of sorafenib, DNase I, IL4 neutralization antibody and GPX4 in tumor growth were explored through in vivo experiments.

RESULTS

Sorafenib induced MET formation in M2 macrophages rather than M1 macrophages derived from both human and mice. In Hepa1-6 HCC mice, METs clearance by DNase I improved response to sorafenib therapy, detected by tumor weight, tumor growth curve, tumor volume, and survival. By screening candidate cytokines that affect macrophage function, we found that sorafenib-promoting IL4 secretion by HCC cells plays a crucial role in sorafenib-induced MET formation. Understanding the critical role of IL4 in sorafenib-induced MET formation led us to find that IL4 neutralization significantly improved the efficiency of sorafenib in HCC models. Mechanistically, we discovered that sorafenib increased the expression of ARHGDIG in HCC cells, which led to the release of IL4. In M2 macrophages, IL4 triggered MET formation by elevating the mRNA and protein expression of peptidyl arginine deiminase 4 (PADI4) rather than PADI2. In HCC models, GSK484 inhibition of PADI4 could consistently weaken sorafenib resistance and improve sorafenib efficiency. Importantly, we discovered that METs contribute to sorafenib resistance by inhibiting the ferroptosis of HCC cells. Meanwhile, PADI4 inhibition or DNase I could reverse the sorafenib resistance caused by METs-inhibiting ferroptosis of HCC cells.

CONCLUSION

Our study concludes that sorafenib-induced METs inhibit the ferroptosis of tumor cells, suggesting that targeting the IL4/PADI4/METs axis in HCC could reduce or prevent sorafenib resistance.

Unlocking ferroptosis in prostate cancer - the road to novel therapies and imaging markers

Ferroptosis is a distinct form of regulated cell death that is predominantly driven by the build-up of intracellular iron and lipid peroxides. Ferroptosis suppression is widely accepted to contribute to the pathogenesis of several tumours including prostate cancer. Results from some studies reported that prostate cancer cells can be highly susceptible to ferroptosis inducers, providing potential for an interesting new avenue of therapeutic intervention for advanced prostate cancer. In this Perspective, we describe novel molecular underpinnings and metabolic drivers of ferroptosis, analyse the functions and mechanisms of ferroptosis in tumours, and highlight prostate cancer-specific susceptibilities to ferroptosis by connecting ferroptosis pathways to the distinctive metabolic reprogramming of prostate cancer cells. Leveraging these novel mechanistic insights could provide innovative therapeutic opportunities in which ferroptosis induction augments the efficacy of currently available prostate cancer treatment regimens, pending the elimination of major bottlenecks for the clinical translation of these treatment combinations, such as the development of clinical-grade inhibitors of the anti-ferroptotic enzymes as well as non-invasive biomarkers of ferroptosis. These biomarkers could be exploited for diagnostic imaging and treatment decision-making.

Sorafenib Encapsulated Poly(ester amide) Nanoparticles for Efficient and Biosafe Prostate Cancer Therapy

Prostate cancer (PCa) with a high incidence worldwide is a serious threat to men's health. Despite the continuous development of treatment strategies for PCa in recent years, the long-term prognosis of patients is still poor. Hence, the discovery and development of novel, secure, and efficient therapeutic approaches hold significant clinical significance. Although sorafenib (SOR) displays potential as a therapeutic option for PCa, its clinical efficacy is hindered by drug resistance, limited water solubility, and rapid metabolism. Therefore, we proposed to prepare nanoparticles (named SOR@8P4 NPs) utilizing the phenylalanine-based poly(ester amide) polymer (8P4) as the drug carrier to enhance the solubility and drug stability of SOR and improve the therapeutic targeting and bioavailability. SOR@8P4 NPs had high stability and showed acid-responsive drug release at the acidic tumor microenvironment. Additionally, SOR@8P4 NPs demonstrated more remarkable anticancer, antimetastatic, and antiproliferative abilities in vitro, compared with those of free drugs. SOR@8P4 NPs showed high tumor targeting and significantly inhibited tumor growth in vivo. In summary, the drug delivery system of SOR@8P4 NPs provides new ideas for the clinical treatment of PCa.

Research progress of ferroptosis regulating lipid peroxidation and metabolism in occurrence and development of primary liver cancer

As a highly aggressive tumor, the pathophysiological mechanism of primary liver cancer has attracted much attention. In recent years, factors such as ferroptosis regulation, lipid peroxidation and metabolic abnormalities have emerged in the study of liver cancer, providing a new perspective for understanding the development of liver cancer. Ferroptosis regulation, lipid peroxidation and metabolic abnormalities play important roles in the occurrence and development of liver cancer. The regulation of ferroptosis is involved in apoptosis and necrosis, affecting cell survival and death. Lipid peroxidation promotes oxidative damage and promotes the invasion of liver cancer cells. Metabolic abnormalities, especially the disorders of glucose and lipid metabolism, directly affect the proliferation and growth of liver cancer cells. Studies of ferroptosis regulation and lipid peroxidation may help to discover new therapeutic targets and improve therapeutic outcomes. The understanding of metabolic abnormalities can provide new ideas for the prevention of liver cancer, and reduce the risk of disease by adjusting the metabolic process. This review focuses on the key roles of ferroptosis regulation, lipid peroxidation and metabolic abnormalities in this process.

A novel ESIPT fluorescent probe for early detection and assessment of ferroptosis-mediated acute kidney injury via peroxynitrite fluctuation

BACKGROUND

Acute kidney injury (AKI) poses a severe risk to public health, mostly manifested by damage and death of renal tubular epithelial cells. However, routine blood examination, a conventional approach for clinical detection of AKI, is not available for identifying early-stage AKI. Plenty of reported methods were lack of early biomarkers and real time evaluation tools, which resulted in a vital challenge for early diagnosis of AKI. Therefore, developing novel probes for early detection and assessment of AKI is exceedingly crucial.

RESULTS

Based on ESIPT mechanism, a new fluorescent probe (MEO-NO) with 2-(2'-hydroxyphenyl) benzothiazole (HBT) derivatives as fluorophore has been synthesized for dynamic imaging peroxynitrite (ONOO-) levels in ferroptosis-mediated AKI. Upon the addition of ONOO-, MEO-NO exhibited obvious fluorescence changes, a significant Stokes shift (130 nm) and rapid response (approximately 45 s), and featured exceptional sensitivity (LOD = 7.28 nM) as well as high selectivity from the competitive species at physiological pH. In addition, MEO-NO was conducive to the biological depth imaging ONOO- in cells, zebrafish, and mice. Importantly, MEO-NO could monitor ONOO- levels during sorafenib-induced ferroptosis and CP-induced AKI. With the assistance of MEO-NO, we successfully visualized and tracked ONOO- variations for early detection and assessment of ferroptosis-mediated AKI in cells, zebrafish and mice models.

SIGNIFICANCE AND NOVELTY

Benefiting from the superior performance of MEO-NO, experimental results further demonstrated that the levels of ONOO- was overexpressed during ferroptosis-mediated AKI in cells, zebrafish, and mice models. The developed novel probe MEO-NO provided a strong visualization tool for imagining ONOO-, which might be a potential method for the prevention, diagnosis, and treatment of ferroptosis-mediated AKI.

Effective detection of BRAFV595E mutation in canine urothelial and prostate carcinomas using immunohistochemistry

Canine urothelial carcinoma (UC) and prostate carcinoma (PC) frequently exhibit the BRAFV595E mutation, akin to the BRAFV600E mutation common in various human cancers. Since the initial discovery of the BRAF mutation in canine cancers in 2015, PCR has been the standard method for its detection in both liquid and tissue biopsies. Considering the similarity between the canine BRAFV595E and human BRAFV600E mutations, we hypothesized that immunohistochemistry (IHC) using a BRAFV600E-specific antibody could effectively identify the canine mutant BRAFV595E protein. We tested 122 canine UC (bladder n = 108, urethra n = 14), 21 PC, and benign tissue using IHC and performed digital droplet PCR (ddPCR) on all 122 UC and on 14 IHC positive PC cases. The results from ddPCR and IHC were concordant in 99% (135/136) of the tumours. Using IHC, BRAFV595E was detected in 72/122 (59%) UC and 14/21 (65%) PC. Staining of all benign bladder and prostate tissues was negative. If present, mutant BRAF staining was homogenous, with rare intratumour heterogeneity in three (4%) cases of UC. Additionally, the BRAFV595E mutation was more prevalent in tumours with urothelial morphology, and less common in glandular PC or UC with divergent differentiation. This study establishes that BRAFV600-specific IHC is a reliable and accurate method for detecting the mutant BRAFV595E protein in canine UC and PC. Moreover, the use of IHC, especially with tissue microarrays, provides a cost-efficient test for large-scale screening of canine cancers for the presence of BRAF mutations. This advancement paves the way for further research to define the prognostic and predictive role of this tumour marker in dogs and use IHC to stratify dogs for the treatment with BRAF inhibitors.

Meningioma achieves malignancy and erastin-induced ferroptosis resistance through FOXM1-AURKA-NRF2 axis

The oncogene Aurora kinase A (AURKA) has been implicated in various tumor, yet its role in meningioma remains unexplored. Recent studies have suggested a potential link between AURKA and ferroptosis, although the underlying mechanisms are unclear. This study presented evidence of AURKA upregulation in high grade meningioma and its ability to enhance malignant characteristics. We identified AURKA as a suppressor of erastin-induced ferroptosis in meningioma. Mechanistically, AURKA directly interacted with and phosphorylated kelch-like ECH-associated protein 1 (KEAP1), thereby activating nuclear factor erythroid 2 related factor 2 (NFE2L2/NRF2) and target genes transcription. Additionally, forkhead box protein M1 (FOXM1) facilitated the transcription of AURKA. Suppression of AURKA, in conjunction with erastin, yields significant enhancements in the prognosis of a murine model of meningioma. Our study elucidates an unidentified mechanism by which AURKA governs ferroptosis, and strongly suggests that the combination of AURKA inhibition and ferroptosis-inducing agents could potentially provide therapeutic benefits for meningioma treatment.

Exosome-derived circUPF2 enhances resistance to targeted therapy by redeploying ferroptosis sensitivity in hepatocellular carcinoma

BACKGROUND

Advanced hepatocellular carcinoma (HCC) can be treated with sorafenib, which is the primary choice for targeted therapy. Nevertheless, the effectiveness of sorafenib is greatly restricted due to resistance. Research has shown that exosomes and circular RNAs play a vital role in the cancer's malignant advancement. However, the significance of exosomal circular RNAs in the development of resistance to sorafenib in HCC remains uncertain.

METHODS

Ultracentrifugation was utilized to isolate exosomes (Exo-SR) from the sorafenib-resistant HCC cells' culture medium. Transcriptome sequencing and differential expression gene analysis were used to identify the targets of Exo-SR action in HCC cells. To identify the targets of Exo-SR action in HCC cells, transcriptome sequencing and analysis of differential expression genes were employed. To evaluate the impact of exosomal circUPF2 on resistance to sorafenib in HCC, experiments involving gain-of-function and loss-of-function were conducted. RNA pull-down assays and mass spectrometry analysis were performed to identify the RNA-binding proteins interacting with circUPF2. RNA immunoprecipitation (RIP), RNA pull-down, electrophoretic mobility shift assay (EMSA), immunofluorescence (IF) -fluorescence in situ hybridization (FISH), and rescue assays were used to validate the interactions among circUPF2, IGF2BP2 and SLC7A11. Finally, a tumor xenograft assay was used to examine the biological functions and underlying mechanisms of Exo-SR and circUPF2 in vivo.

RESULTS

A novel exosomal circRNA, circUPF2, was identified and revealed to be significantly enriched in Exo-SR. Exosomes with enriched circUPF2 enhanced sorafenib resistance by promoting SLC7A11 expression and suppressing ferroptosis in HCC cells. Mechanistically, circUPF2 acts as a framework to enhance the creation of the circUPF2-IGF2BP2-SLC7A11 ternary complex contributing to the stabilization of SLC7A11 mRNA. Consequently, exosomal circUPF2 promotes SLC7A11 expression and enhances the function of system Xc- in HCC cells, leading to decreased sensitivity to ferroptosis and resistance to sorafenib.

CONCLUSIONS

The resistance to sorafenib in HCC is facilitated by the exosomal circUPF2, which promotes the formation of the circUPF2-IGF2BP2-SLC7A11 ternary complex and increases the stability of SLC7A11 mRNA. Focusing on exosomal circUPF2 could potentially be an innovative approach for HCC treatment.

Protein and metabolic profiles of tyrosine kinase inhibitors co-resistant liver cancer cells

Hepatocellular Carcinoma (HCC) patients often develop resistance to tyrosine kinase inhibitors (TKIs) like sorafenib (SR) and lenvatinib (RR). We established HCC cell lines resistant to these drugs and analyzed the correlation between protein and metabolite profiles using bioinformatics. Our analysis revealed overexpression of MISP, CHMP2B, IL-18, TMSB4X, and EFEMP1, and downregulation of IFITM3, CA4, AGR2, and SLC51B in drug-resistant cells. Differential signals are mainly enriched in steroid hormone biosynthesis, cell adhesion, and immune synapses, with metabolic pathways including cytochrome P450 drug metabolism, amino acid metabolism, and glycolysis. Proteomics and metabolomics analysis showed co-enrichment signals in drug metabolism, amino acids, glucose metabolism, ferroptosis, and other biological processes. Knocking down MISP, CHMP2B, IL-18, TMSB4X, and EFEMP1 significantly reduced drug resistance, indicating their potential as therapeutic response biomarkers. This study characterizes protein and metabolic profiles of drug-resistant HCC cells, exploring metabolite-protein relationships to enhance understanding of drug resistance mechanisms and clinical treatment.

Oxygen Self-Supplied Perfluorocarbon-Modified Micelles for Enhanced Cancer Photodynamic Therapy and Ferroptosis

Photodynamic therapy (PDT) and ferroptosis show significant potential in tumor treatment. However, their therapeutic efficacy is often hindered by the oxygen-deficient tumor microenvironment and the challenges associated with efficient intracellular drug delivery into tumor cells. Toward this end, this work synthesized perfluorocarbon (PFC)-modified Pluronic F127 (PFC-F127), and then exploits it as a carrier for codelivery of photosensitizer Chlorin e6 (Ce6) and the ferroptosis promoter sorafenib (Sor), yielding an oxygen self-supplying nanoplatform denoted as Ce6-Sor@PFC-F127. The PFCs on the surface of the micelle play a crucial role in efficiently solubilizing and delivering oxygen as well as increasing the hydrophobicity of the micelle surface, giving rise to enhanced endocytosis by cancer cells. The incorporation of an oxygen-carrying moiety into the micelles enhances the therapeutic impact of PDT and ferroptosis, leading to amplified endocytosis and cytotoxicity of tumor cells. Hypotonic saline technology was developed to enhance the cargo encapsulation efficiency. Notably, in a murine tumor model, Ce6-Sor@PFC-F127 effectively inhibited tumor growth through the combined use of oxygen-enhanced PDT and ferroptosis. Taken together, this work underscores the promising potential of Ce6-Sor@PFC-F127 as a multifunctional therapeutic nanoplatform for the codelivery of multiple cargos such as oxygen, photosensitizers, and ferroptosis inducers.

Emerging role of immunogenic cell death in cancer immunotherapy

Cancer immunotherapy, such as immune checkpoint blockade (ICB), has emerged as a groundbreaking approach for effective cancer treatment. Despite its considerable potential, clinical studies have indicated that the current response rate to cancer immunotherapy is suboptimal, primarily attributed to low immunogenicity in certain types of malignant tumors. Immunogenic cell death (ICD) represents a form of regulated cell death (RCD) capable of enhancing tumor immunogenicity and activating tumor-specific innate and adaptive immune responses in immunocompetent hosts. Therefore, gaining a deeper understanding of ICD and its evolution is crucial for developing more effective cancer therapeutic strategies. This review focuses exclusively on both historical and recent discoveries related to ICD modes and their mechanistic insights, particularly within the context of cancer immunotherapy. Our recent findings are also highlighted, revealing a mode of ICD induction facilitated by atypical interferon (IFN)-stimulated genes (ISGs), including polo-like kinase 2 (PLK2), during hyperactive type I IFN signaling. The review concludes by discussing the therapeutic potential of ICD, with special attention to its relevance in both preclinical and clinical settings within the field of cancer immunotherapy.

Molecular mechanisms of mitochondria-mediated ferroptosis: a potential target for antimalarial interventions

Ferroptosis is an iron-dependent form of regulated cell death characterized by glutathione (GSH) depletion, glutathione peroxidase 4 (GPX4) inactivation, and the build-up of lipotoxic reactive species. Ferroptosis-targeted induction is a promising therapeutic approach for addressing antimalarial drug resistance. In addition to being the primary source of intracellular energy supply and reactive oxygen species (ROS) generation, mitochondria actively participate in diverse forms of regulated cell death, including ferroptosis. Altered mitochondrial morphology and functionality are attributed to ferroptosis. Diverse mitochondria-related proteins and metabolic activities have been implicated in fine-tuning the action of ferroptosis inducers. Herein, we review recent progress in this evolving field, elucidating the numerous mechanisms by which mitochondria regulate ferroptosis and giving an insight into the role of the organelle in ferroptosis. Additionally, we present an overview of how mitochondria contribute to ferroptosis in malaria. Furthermore, we attempt to shed light on an inclusive perspective on how targeting malaria parasites' mitochondrion and attacking redox homeostasis is anticipated to induce ferroptosis-mediated antiparasitic effects.

Ferroptosis in cancer: From molecular mechanisms to therapeutic strategies

Ferroptosis is a non-apoptotic form of regulated cell death characterized by the lethal accumulation of iron-dependent membrane-localized lipid peroxides. It acts as an innate tumor suppressor mechanism and participates in the biological processes of tumors. Intriguingly, mesenchymal and dedifferentiated cancer cells, which are usually resistant to apoptosis and traditional therapies, are exquisitely vulnerable to ferroptosis, further underscoring its potential as a treatment approach for cancers, especially for refractory cancers. However, the impact of ferroptosis on cancer extends beyond its direct cytotoxic effect on tumor cells. Ferroptosis induction not only inhibits cancer but also promotes cancer development due to its potential negative impact on anticancer immunity. Thus, a comprehensive understanding of the role of ferroptosis in cancer is crucial for the successful translation of ferroptosis therapy from the laboratory to clinical applications. In this review, we provide an overview of the recent advancements in understanding ferroptosis in cancer, covering molecular mechanisms, biological functions, regulatory pathways, and interactions with the tumor microenvironment. We also summarize the potential applications of ferroptosis induction in immunotherapy, radiotherapy, and systemic therapy, as well as ferroptosis inhibition for cancer treatment in various conditions. We finally discuss ferroptosis markers, the current challenges and future directions of ferroptosis in the treatment of cancer.

Iron, Oxidative Stress, and Metabolic Dysfunction-Associated Steatotic Liver Disease

Excess free iron is a substrate for the formation of reactive oxygen species (ROS), thereby augmenting oxidative stress. Oxidative stress is a well-established cause of organ damage in the liver, the main site of iron storage. Ferroptosis, an iron-dependent mechanism of regulated cell death, has recently been gaining attention in the development of organ damage and the progression of liver disease. We therefore summarize the main mechanisms of iron metabolism, its close connection to oxidative stress and ferroptosis, and its particular relevance to disease mechanisms in metabolic-dysfunction-associated fatty liver disease and potential targets for therapy from a clinical perspective.