This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1186/s13046-024-03113-9.

BackgroundAZIN1 is a cell cycle regulator that is upregulated in a variety of cancers. AZIN1 overexpression can induce a more aggressive tumor phenotype via increased binding and resultant inhibition of antizyme. Antizyme is a protein that normally functions as an anti-tumor regulator that facilitates the deactivation of several growth-promoting proteins including c-Myc. MYC plays a critical role in medulloblastoma pathogenesis. Its amplification serves as a defining characteristic of group 3 medulloblastomas, associated with the most aggressive clinical course, greater frequency of metastases, and shorter survival times.MethodsMedulloblastoma tissues (68 TMA, and 45 fresh tissues, and 31 controls) were stained (fluorescence and immunohistochemical) for AZIN1. Western blotting and ELISA were used to detect the AZIN1 level. Phenotypically aggressive cellular features were measured by increased invasion, colony formation and proliferation. CRISPR-Cas9-mediated AZIN1 knocked-out cells were orthotopically implanted in the cerebellum of nude mice (n = 8/group) with a stereotactic frame. Tumor growth was monitored using the In Vivo Imaging System (IVIS).ResultsHere, we investigated the role of AZIN1 expression in medulloblastoma. We found that overexpression of AZIN1 in medulloblastoma cells induces phenotypically aggressive features. Conducting in vivo studies we found that knocking-out AZIN1 in tumors corresponds with reduced tumor progression and prolonged survival. Clinical specimens are revealing that AZIN1 is highly expressed and directly correlates with MYC amplification status in patients.ConclusionThese data implicate AZIN1 as a putative regulator of medulloblastoma pathogenesis and suggest that it may have clinical application as both a biomarker and novel therapeutic target.

PurposeGlucose starvation induces the accumulation of disulfides and F-actin collapse in cells with high expression of SLC7A11, a phenomenon termed disulfidptosis. This study aimed to confirm the existence of disulfidptosis in pancreatic ductal adenocarcinoma (PDAC) and elucidate the role of Cancer Susceptibility 8 (CASC8) in this process.MethodsThe existence of disulfidptosis in PDAC was assessed using flow cytometry and F-actin staining. CASC8 expression and its clinical correlations were analyzed using data from The Cancer Genome Atlas (TCGA) and further verified by chromogenic in situ hybridization assay in PDAC tissues. Cells with CASC8 knockdown and overexpression were subjected to cell viability, EdU, transwell assays, and used to establish subcutaneous and orthotopic tumor models. Disulfidptosis was detected by flow cytometry and immunofluorescence assays. RNA sequencing and metabolomics analysis were performed to determine the metabolic pathways which were significantly affected after CASC8 knockdown. We detected the glucose consumption and the NADP+/NADPH ratio to investigate alterations in metabolic profiles. RNA immunoprecipitation combined with fluorescence in situ hybridization assay was used to identify protein-RNA interactions. Protein stability, western blotting and quantitative real-time PCR assays were performed to reveal potential molecular mechanism.ResultsDisulfidptosis was observed in PDAC and could be significantly rescued by disulfidptosis inhibitors. CASC8 expression was higher in PDAC samples compared to normal pancreatic tissue. High CASC8 expression correlated with a poor prognosis for patients with PDAC and contributed to cancer progression in vitro and in vivo. Furthermore, CASC8 was associated with disulfidptosis resistance under glucose starvation conditions in PDAC. Mechanistically, CASC8 interacted with c-Myc to enhance the stability of c-Myc protein, leading to the activation of the pentose phosphate pathway, a reduction of the NADP+/NADPH ratio and ultimately inhibiting disulfidptosis under glucose starvation conditions.ConclusionsThis study provides evidence for the existence of disulfidptosis in PDAC and reveals the upregulation of CASC8 in this malignancy. Furthermore, we demonstrate that CASC8 acts as a crucial regulator of the pentose phosphate pathway and disulfidptosis, thereby promoting PDAC progression.

BackgroundCirculating tumour cells (CTCs) and tumour-derived extracellular vesicles (tdEVs) have great potential for monitoring therapy response and early detection of tumour relapse, facilitating personalized adjuvant therapeutic strategies. However, their low abundance in peripheral blood limits their informative value. In this study, we explored the presence of CTCs and tdEVs collected intraoperatively from a tumour-draining vein (DV) and via a central venous catheter (CVC) prior to tumour resection.MethodsCellSearch analyses of 395 blood samples from 306 patients with gastrointestinal tumours and 93 blood samples from healthy donors were used to establish and validate gates for the automated detection of CTCs and tdEVs with ACCEPT software and R scripts. The selected gate settings were applied to 227 samples of 142 patients with colorectal cancer (CRC) from two independent collectives. Phenotypic features were obtained via numeric analysis of their fluorescence signals (e.g. size, shape, and intensity) and were used for calculating diversity using Shannon index (SI) of clusters generated via the k-means algorithm after Uniform Manifold Approximation and Projection (UMAP) pre-processing, and standard deviation (SD).ResultsCTCs and tdEVs were more abundant in the DV samples compared to CVC samples (p < 0.05). tdEVs were detected in higher numbers than CTCs in both compartments. Importantly, tdEVs in CVCs were associated with tumor spread, whereas CTCs in DVs were linked to tumor size. In both compartments, the prognostic value of tdEVs for overall survival (OS) surpassed that of CTCs, as demonstrated by univariate, multivariate, and Kaplan-Meier analyses. CTCs and tdEVs in DVs were phenotypically distinct, being larger, more eccentric, and displaying stronger cytokeratin intensities (p < 0.05) compared to those in CVC samples. Furthermore, increased diversity in CTC and tdEV phenotypes was significantly associated with shorter survival, validating the prognostic relevance of the SD-diversity metric.ConclusionOur study demonstrates that DV sampling significantly enhances the detection of prognostically relevant CTCs and tdEVs in CRC patients, underscoring the superior prognostic significance of tdEVs compared to CTCs. Importantly, the combined phenotypic diversity of both markers emerges as a more powerful biomarker than their enumeration alone. These findings suggest that comprehensive, automated analysis of CTCs and tdEVs in DVs may open new avenues for tailoring individualized therapies in CRC patients.

BackgroundGlioblastoma multiforme (GBM) exhibits a cellular hierarchy with a subpopulation of stem-like cells known as glioblastoma stem cells (GSCs) that drive tumor growth and contribute to treatment resistance. NAD(H) emerges as a crucial factor influencing GSC maintenance through its involvement in diverse biological processes, including mitochondrial fitness and DNA damage repair. However, how GSCs leverage metabolic adaptation to obtain survival advantage remains elusive.MethodsA multi-step process of machine learning algorithms was implemented to construct the glioma stemness-related score (GScore). Further in silico and patient tissue analyses validated the predictive ability of the GScore and identified a potential target, CYP3A5. Loss-of-function or gain-of-function genetic experiments were performed to assess the impact of CYP3A5 on the self-renewal and chemoresistance of GSCs both in vitro and in vivo. Mechanistic studies were conducted using nontargeted metabolomics, RNA-seq, seahorse, transmission electron microscopy, immunofluorescence, flow cytometry, ChIP‒qPCR, RT‒qPCR, western blotting, etc. The efficacy of pharmacological inhibitors of CYP3A5 was assessed in vivo.ResultsBased on the proposed GScore, we identify a GSC target CYP3A5, which is highly expressed in GSCs and temozolomide (TMZ)-resistant GBM patients. This elevated expression of CYP3A5 is attributed to transcription factor STAT3 activated by EGFR signaling or TMZ treatment. Depletion of CYP3A5 impairs self-renewal and TMZ resistance of GSCs. Mechanistically, CYP3A5 maintains mitochondrial fitness to promote GSC metabolic adaption through the NAD⁺/NADH-SIRT1-PGC1α axis. Additionally, CYP3A5 enhances the activity of NAD-dependent enzyme PARP to augment DNA damage repair. Treatment with CYP3A5 inhibitor alone or together with TMZ effectively suppresses tumor growth in vivo.ConclusionTogether, this study suggests that GSCs activate STAT3 to upregulate CYP3A5 to fine-tune NAD⁺/NADH for the enhancement of mitochondrial functions and DNA damage repair, thereby fueling tumor stemness and conferring TMZ resistance, respectively. Thus, CYP3A5 represents a promising target for GBM treatment.

On September 23–24 (2024) the 6th Workshop IRE on Translational Oncology, titled “Cancer Organoids as Reliable Disease Models to Drive Clinical Development of Novel Therapies,” took place at the IRCCS Regina Elena Cancer Institute in Rome. This prominent international conference focused on tumor organoids, bringing together leading experts from around the world.A central challenge in precision oncology is modeling the dynamic tumor ecosystem, which encompasses numerous elements that evolve spatially and temporally. Patient-derived 3D culture models, including organoids, explants, and engineered or bioprinted systems, have recently emerged as sophisticated tools capable of capturing the complexity and diversity of cancer cells interacting within their microenvironments. These models address critical unmet needs in precision medicine, particularly in aiding clinical decision-making. The rapid development of these human tissue avatars has enabled advanced modeling of cellular alterations in disease states and the screening of compounds to uncover novel therapeutic pathways.Throughout the event, distinguished speakers shared their expertise and research findings, illustrating how organoids are transforming our understanding of treatment resistance, metastatic dynamics, and the interaction between tumors and the surrounding microenvironment.This conference served as a pivotal opportunity to strengthen international collaborations and spark innovative translational approaches. Its goal was to accelerate the shift from preclinical research to clinical application, paving the way for increasingly personalized and effective cancer therapies.

BackgroundThe androgen receptor (AR), a ligand-dependent transcription factor, plays a key role in regulating prostate cancer (PCa) growth. The novel bipolar androgen therapy (BAT) uses supraphysiological androgen levels (SAL) that suppresses growth of PCa cells and induces cellular senescence functioning as a tumor suppressive mechanism. The role of long non-coding RNAs (lncRNAs) in the regulation of SAL-mediated senescence remains unclear. This study focuses on the SAL-repressed lncRNA MIR503HG, examining its involvement in androgen-controlled cellular senescence in PCa.MethodsTranscriptome and ChIP-Seq analyses of PCa cells treated with SAL were conducted to identify SAL-downregulated lncRNAs. Expression levels of MIR503HG were analyzed in 691 PCa patient tumor samples, mouse xenograft tumors and treated patient-derived xenografts. Knockdown and overexpression experiments were performed to assess the role of MIR503HG in cellular senescence and proliferation using senescence-associated β-Gal assays, qRT-PCRs, and Western blotting. The activity of MIR503HG was confirmed in PCa tumor spheroids.ResultsA large patient cohort analysis shows that MIR503HG is overexpressed in metastatic PCa and is associated with reduced patient survival, indicating its potential oncogenic role. Notably, SAL treatment suppresses MIR503HG expression across four different PCa cell lines and patient-derived xenografts but interestingly not in the senescence-resistant LNCaP Abl EnzaR cells. Functional assays reveal that MIR503HG promotes PCa cell proliferation and inhibits SAL-mediated cellular senescence, partly through miR-424-5p. Mechanistic analyses and rescue experiments indicate that MIR503HG regulates the AKT-p70S6K and the p15INK4b-pRb pathway. Reduced expression of MIR503HG by SAL or knockdown resulted in decreased BRCA2 levels suggesting a role in DNA repair mechanisms and potential implications for PARP inhibitor sensitivity by SAL used in BAT clinical trial.ConclusionsThe lncRNA MIR503HG acts as an oncogenic regulator in PCa by repressing cellular senescence. SAL-induced suppression of MIR503HG enhances the tumor-suppressive effects of AR signaling, suggesting that MIR503HG could serve as a biomarker for BAT responsiveness and as a target for combination therapies with PARP inhibitors.

BackgroundApproximately half of all human cancers harbour mutations in the p53 gene, leading to the generation of neomorphic p53 mutant proteins. These mutants can exert gain-of-function (GOF) effects, potentially promoting tumour progression. However, the clinical significance of p53 GOF mutations, as well as the selectivity of individual variants, remains controversial and unclear.MethodsTo elucidate the metabolic regulations and molecular underpinnings associated with the specific p53R270H and p53R172H mutant variants (the mouse equivalents of human p53R273H and p53R175H, respectively), we employed a comprehensive approach. This included integrating global metabolomic analysis with epigenomic and transcriptomic profiling in mouse pancreatic cancer cells. Additionally, we assessed metabolic parameters such as oxygen consumption rate and conducted analyses of proliferation and cell–cell competition to validate the biological impact of metabolic changes on pancreatic ductal adenocarcinoma (PDAC) phenotype. Our findings were further corroborated through analysis of clinical datasets from human cancer cohorts.ResultsOur investigation revealed that the p53R270H variant, but not p53R172H, sustains mitochondrial function and energy production while also influencing cellular antioxidant capacity. Conversely, p53R172H, while not affecting mitochondrial metabolism, attenuates the activation of pro-tumorigenic metabolic pathways such as the urea cycle. Thus, the two variants selectively control different metabolic pathways in pancreatic cancer cells. Mechanistically, p53R270H induces alterations in the expression of genes associated with oxidative stress and reduction in mitochondrial respiration. In contrast, p53R172H specifically impacts the expression levels of enzymes involved in the urea metabolism. However, our analysis of cell proliferation and cell competition suggested that the expression of either p53R270H or p53R172H does not influence confer any selective advantage to this cellular model in vitro. Furthermore, assessment of mitochondrial priming indicated that the p53R270H-driven mitochondrial effect does not alter cytochrome c release or the apoptotic propensity of pancreatic cancer cells.ConclusionsOur study elucidates the mutant-specific impact of p53R270H and p53R172H on metabolism of PDAC cancer cells, highlighting the need to shift from viewing p53 mutant variants as a homogeneous group of entities to a systematic assessment of each specific p53 mutant protein. Moreover, our finding underscores the importance of further exploring the significance of p53 mutant proteins using models that more accurately reflect tumor ecology.

BackgroundThe response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE) treatment and its underlying mechanisms remain elusive. This study investigates the role of enzymes involved in fatty acid activation, specifically Acyl-CoA synthetase long chain 4 (ACSL4), in HCC patients treated with postoperative adjuvant TACE (PA-TACE) and in nutrient-deprived HCC cells.MethodsWe examined the expression of ACSL4 and its family members in HCC clinical samples and cell lines. The clinical significance of ACSL4, particularly regarding the prognosis of patients treated with PA-TACE, was assessed using two independent HCC cohorts. We further explored the role of ACSL4 in glucose starvation-induced cell death in HCC cells and xenograft mouse models.ResultsAmong the family members, ACSL4 is the most up-regulated enzyme, associated with poor survival in HCC patients, particularly in post-recurrent TACE-treated patients in a Singapore cohort. ACSL4 is essential for HCC cell survival in response to glucose starvation, rather than to hypoxia or to the combination of hypoxia with doxorubicin or cisplatin. ACSL4-mediated arachidonic acid (AA) metabolism supports mitochondrial β-oxidation and energy production. CCAAT/enhancer binding protein α (CEBPA) transcriptionally regulates ACSL4 by binding 3 motifs (-623 to -613, -1197 to -1187 and -1745 to -1735) of ACSL4 upstream promoter region, enhancing its pro-survival effects. Furthermore, canagliflozin (Cana), a clinical-approved drug for type 2 diabetes, mimics glucose starvation and inhibits the growth of ACSL4-low xenograft tumors. Moreover, high ACSL4 or CEBPA expressions correlate with increased recurrence susceptibility after PA-TACE in the China-Guangxi HCC cohort.ConclusionsThe CEBPA-ACSL4 pathway is critical in protecting HCC cells from glucose starvation-induced cell death, suggesting that ACSL4 and CEBPA could serve as valuable prognostic indicators and potential therapeutic targets in the context of PA-TACE treatment for HCC.Graphical TACE is the first-line treatment for intermediate-stage HCC patients with unresectable tumor and a common postoperative adjuvant (PA) treatment. The present study found that HCC patients with the presence of CEBPA-ACSL4 expression in tumor are more resistant to TACE, susceptible for PA-TACE relapse and poorer survival. Mechanically, ACSL4 is essential for fatty acid activation particularly conversion of arachidonic acid (AA) into AA-CoA, which promotes lipid anabolism in nutrition-replete condition and lipid catabolism in glucose-deplete condition. As a result, ACSL4-high HCC cells, in response to glucose restriction (rather than hypoxia and chemotherapeutic drugs), can donor mitochondrial energy production through β-oxidation and protect HCC cells from mitochondrial membrane impairment and cell death in vitro and in vivo. In addition, CEBPA transcriptionally activates ACSL4 , and knockout of CEBPA aborted ACSL4-mediated lipid metabolism.

BackgroundPatients with metastatic hepatoblastoma are treated with severely toxic first-line chemotherapies in combination with surgery. Yet, inadequate response of lung metastases to neo-adjuvant chemotherapy still compromises patient outcomes making new treatment strategies, tailored to more efficient lung clearance, mandatory.MethodsWe harnessed a comprehensive patient-derived xenograft platform and a variety of in vitro and in vivo assays to establish the preclinical and biological rationale for a new drug for patients with metastatic hepatoblastoma.ResultsThe testing of a library of established drugs on patient-derived xenografts identified histone deacetylase inhibitors, most notably panobinostat, to be highly efficacious on hepatoblastoma cells, as compared to non-cancerous cells. Molecularly, the anti-tumor effect of panobinostat is mediated by posttranslational obstruction of the MYC oncoprotein as a result of dual specificity phosphatase 1 upregulation, thereby leading to growth inhibition and programmed cell death. Of clinical importance, upregulation of the MYC target gene nucleophosmin 1 is indicative of response to panobinostat and associated with metastatic disease in patients with hepatoblastoma. The combination of panobinostat with the current SIOPEL 4 induction protocol, consisting of cisplatin and doxorubicin, revealed high synergies already at low nanomolar levels. The simulation of a clinical trial, with this combination therapy, in patient-derived xenograft models, and ultimately heterotypic lung metastasis mimics clearly underscored the potency of this approach.ConclusionIntegrated studies define MYC inhibition by panobinostat as a novel treatment element to be introduced into the therapeutic strategy for patients with metastatic hepatoblastoma.