Journal of Experimental & Clinical Cancer Research最新文献

Purpose: Glucose 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.

Methods: The 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.

Results: Disulfidptosis 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.

Conclusions: This 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.

Background: Exosomes, as extracellular membrane vesicles, play important roles in intercellular communication and can influence tumour progression. Circular RNAs (circRNAs) have been reported in various malignancies and are also important components of exosomes. However, the role of exosomal circRNAs in gastric cancer (GC) progression has not been completely clarified.

Methods: The exosomal circRNAs enriched in GC were identified using exosomal circRNA sequencing. The biological function of circMAN1A2 in GC was investigated using a series of in vitro and in vivo experiments. PKH-67 staining was used to label the exosomes. The molecular mechanism of exosomal circMAN1A2 was investigated via mass spectrometry, immunoprecipitation, Western blot, and single-cell RNA-sequencing data analyses.

Results: In our study, we determined that circMAN1A2 (hsa_circ_0000118) was enriched in GC-derived exosomes. Higher circMAN1A2 expression was related to poor survival in GC patients (HR = 2.917, p = 0.0120). Exosomal circMAN1A2 promoted GC progression in vitro and in vivo and suppressed the antitumour activity of T cells. Moreover, circMAN1A2 bound to SFPQ in GC cells and T cells, promoting the G1/S phase transition of the cell cycle in GC cells while inhibiting the activation of the T cell receptor signalling pathway in T cells to decrease antitumour activity. Mechanistically, circMAN1A2 competed with FBXW11 for binding to SFPQ, preventing FBXW11-mediated k48-linked ubiquitination and SFPQ protein degradation, thereby stabilizing SFPQ expression.

Conclusions: Our work confirms the critical role of exosomal circMAN1A2 in the progression and immunosuppression of GC. This novel axis of circMAN1A2-SFPQ provides new insights into exosomal circRNA-based GC diagnostic and therapeutic strategies.

Background: The benefit of universal CAR-T cells over autologous CAR-T cell therapy is that they are a treatment that is ready to use. However, the prevention of graft-versus-host disease (GVHD) and host-versus-graft reaction (HVGR) remains challenging. Deleting class I of human leukocyte antigen (HLA-I) and class II of human leukocyte antigen (HLA-II) can prevent rejection by allogeneic T cells; however, natural killer (NK) cell rejection due to the loss of self-recognition remains unresolved. This study tested whether the overexpression of Lectin-like transcript 1 (LLT1), an NK cell inhibitory ligand, in T cell receptor (TCR) and HLA-I/II disrupted universal CD38-targeting CAR-T cells could prevent rejection by allogeneic NK cells.

Methods: We generated CD38-targeting universal CAR-T cells by transducing T cells with lentiviruses encoding the CD38 CAR and LLT1 constructs. T cells were subjected to CD38, TCR, HLA-I, and HLA-II gene knockdown using CRISPR/Cas9, followed by lentiviral transduction. We performed cytotoxicity, proliferation, and cytokine assays to evaluate the functionality of universal chimeric antigen receptor-T cell (UCAR-T) cells and conducted in vitro and in vivo assays, including allogeneic responses and RNA sequencing, to assess their resistance to allogeneic T and NK cells, anti-leukemia efficacy, and persistence in treating hematologic malignancies.

Results: Genetic editing of CD38 universal CAR-T cells, including CD38, T cell receptor alpha constant (TRAC), beta-2-microglobulin (B2M), and class II major histocompatibility complex transactivator (CIITA) knockdowns, was successfully achieved. In vitro, LLT1 overexpression boosted CAR-T cell proliferation and antitumor activity, leading to a transcriptional signature characterized by elevated stemness-related markers (SELL, BCL6, TCF7, and CD27) and increased levels of IL-10 and other cytokines. It also effectively mitigates rejection by allogeneic NK and T cells. In a humanized T-cell acute lymphoblastic leukemia (T-ALL) model, CD38 allogeneic universal CAR-T cells demonstrated superior survival rates and tumor clearance with reduced inflammatory responses.

Conclusion: According to these results, LLT1 overexpression enhances UCAR-T cell activity and prevents allogeneic rejection, providing essential insights for the development of universal CAR-T cell therapy.

Background: Ovarian cancer (OC) progression is one of the commonest cause of female cancer death. While treatments in clinic includes primary surgery and targeted chemotherapy, curative and survival trends in OC have not significantly improved. Thus, further investigation of the mechanisms regarding OC carcinogenesis and discovery of novel targets is of great importance.

Methods: Human ovarian tissue specimens, RNA sequencing, GEPIA database and bioinformatics analyses were used to analyze the gene correlation, and to identify and validate potential downstream candidates. The biological effects of GPR137-RAB8A-Hedgehog(HH) were investigated using in vitro and in vivo models and methods including qRT-PCR, RNA stability assay, RNA immunoprecipitation assay, GLI-luciferase reporter assay, nucleo-cytoplasmic separation assay, membrane-cytoplasmic separation assay, western blot, co-immunoprecipitation, immunofluorescence staining, cell counting kit-8 assay, wound healing assay, matrigel invasion assay, colony formation assay, xenografts assay, in situ transplantation tumor model of ovarian cancer in nude mice, and immunohistochemistry staining.

Results: GPR137 expression was significantly higher in collected clinical OC tissues, compared with the adjacent normal tissues. Consistently, suppression of GPR137 inhibited human SK-OV-3 and A2780 OC cell proliferation, migration, invasion, and colony formation, whereas overexpression of GPR137 in human OC HO8910 cell exerted the opposite effects on cell biological behaviors. Mechanistically, RAB8A was identified as a downstream target of GPR137, and GPR137 promotes RAB8A expression by promoting RAB8A mRNA stability. By RNA-sequencing and experiments in vitro using multiple ovarian cancer cell models as well as in vivo using subcutaneous xenografts assay and in situ transplantation ovarian cancer model in nude mice, we further demonstrated that RAB8A positively mediated OC progression through activating HH signaling pathway by disassociating the protein-protein complex formation of GLI and SuFu (Suppressor of Fused), which reciprocally enhanced GPR137 activity, forming a regulation loop between HH signaling and GPR137.

Conclusions: Collectively, this study depicts the role of GPR137-RAB8A-HH cascade in the development of OC, deepening our understanding of tumor biomechanics regarding OC progression and providing novel targets for OC therapy in future.

Background: Despite promising preclinical studies, the application of DNA methyltransferase inhibitors in treating patients with solid cancers has thus far produced only modest outcomes. The presence of intratumoral heterogeneity in response to DNA methyltransferase inhibitors could significantly influence clinical efficacy, yet our understanding of the single-cell response to these drugs in solid tumors remains very limited.

Methods: In this study, we used cancer/testis antigen genes as a model for methylation-dependent gene expression to examine the activity of DNA methyltransferase inhibitors and their potential synergistic effect with histone deacetylase inhibitors at the single-cancer cell level. The analysis was performed on breast cancer patient-derived xenograft tumors and cell lines, employing a comprehensive set of techniques, including targeted single-cell mRNA sequencing. Mechanistic insights were further gained through DNA methylation profiling and chromatin structure analysis.

Results: We show that breast cancer tumors and cell cultures exhibit a highly heterogenous response to DNA methyltransferase inhibitors, persisting even under high drug concentrations and efficient DNA methyltransferase depletion. The observed variability in response to DNA methyltransferase inhibitors was independent of cancer-associated aberrations and clonal genetic diversity. Instead, these variations were attributed to stochastic demethylation of regulatory CpG sites and the DNA methylation-independent suppressive function of histone deacetylases.

Conclusions: Our findings point to intratumoral heterogeneity as a limiting factor in the use of DNA methyltransferase inhibitors as single agents in treatment of solid cancers and highlight histone deacetylase inhibitors as essential partners to DNA methyltransferase inhibitors in the clinic.

Background: Triggering receptor expressed on myeloid cells 2 (TREM2), a surface receptor predominantly expressed on myeloid cells, is a major hub gene in pathology-induced immune signaling. However, its function in hepatocellular carcinoma (HCC) remains controversial. This study aimed to evaluate the role of TREM2 in the tumor microenvironment in the context of HCC progression.

Methods: HCC was experimentally induced in wild-type (WT) and Trem2-deficient (Trem2^-/-) mice, and clinical sample analysis and in vitro studies on macrophages were conducted. HCC cells were treated with conditioned medium from WT or Trem2^-/- macrophages, and their malignant phenotypes and underlying mechanisms were analyzed.

Results: TREM2 deficiency reduced liver tumor burden in orthotopic and subcutaneous HCC models by altering CD8⁺ T cell infiltration. Trem2-deficient macrophages presented increased chemokine secretion. TGF-β1 was found to be positively correlated with TREM2 expression in HCC, and TGF-β blockade reversed TREM2 induction. On the other hand, TREM2⁺ macrophages were found to be associated with glycolysis and PKM2 expression in HCC cells; this association may be related to the secretion of IL-1β, which enhances the malignant phenotypes of HCC cells.

Conclusions: These results reveal that TREM2⁺ macrophages play a driving role in HCC progression by suppressing CD8⁺ T cell infiltration and promoting tumor cell glycolysis, providing a new therapeutic target for HCC.

Background: Growing evidence shows that the reprogramming of fatty acid (FA) metabolism plays a key role in HER2-positive (HER2 +) breast cancer (BC) aggressiveness, therapy resistance and cancer stemness. In particular, HER2 + BC has been defined as a "lipogenic disease" due to the functional and bi-directional crosstalk occurring between HER2-mediated oncogenic signaling and FA biosynthesis via FA synthase activity. In this context, the functional role exerted by the reprogramming of CD36-mediated FA uptake in HER2 + BC poor prognosis and therapy resistance remains unclear. In this study, we aimed to elucidate whether enhanced CD36 in mesenchymal HER2 + cancer stem cells (CSCs) is directly involved in anti-HER2 treatment refractoriness in HER2 + BC and to design future metabolism-based approaches targeting both FA reprogramming and the "root" of cancer.

Methods: Molecular, biological and functional characterization of CD36-mediated FA uptake was investigated in HER2 + BC patients, cell lines, epithelial and mesenchymal CSCs. Cell proliferation was analyzed by SRB assay upon treatment with lapatinib, CD36 inhibitor, or Wnt antagonist/agonist. Engineered cell models were generated via lentivirus infection and transient silencing. CSC-like properties and tumorigenesis of HER2 + BC cells with or without CD36 depletion were examined by mammosphere forming efficiency assay, flow cytometry, cell sorting, ALDH activity assay and xenograft mouse model. FA uptake was examined by flow cytometry with FA BODIPY FL C16. Intratumor expression of CSC subsets was evaluated via multiplex immunostaining and immunolocalization analysis.

Results: Molecular data demonstrated that CD36 is significantly upmodulated on treatment in therapy resistant HER2 + BC patients and its expression levels in BC cells is correlated with FA uptake. We provided evidence of a consistent enrichment of CD36 in HER2 + epithelial-mesenchymal transition (EMT)-like CSCs from all tested resistant cell models that mechanistically occurs via Wnt signaling pathway activation. Consistently, both in vitro and in vivo dual blockade of CD36 and HER2 increased the anti-CSC efficacy of anti-HER2 drugs favoring the transition of the therapy resistant mesenchymal CSCs into therapy-sensitive mesenchymal-epithelial transition (MET)-like epithelial state. In addition, expression of CD36 in intratumor HER2 + mesenchymal CSCs is significantly associated with resistance to trastuzumab in HER2 + BC patients.

Conclusions: These results support the metabolo-oncogenic nature of CD36-mediated FA uptake in HER2 + therapy-refractory BC. Our study provides evidence that targeting CD36 might be an effective metabolic therapeutic strategy in the treatment of this malignancy.

Background: Metabolic syndrome represents a pancreatic ductal adenocarcinoma (PDAC) risk factor. Metabolic alterations favor PDAC onset, which occurs early upon dysmetabolism. Pancreatic neoplastic lesions evolve within a dense desmoplastic stroma, consisting in abundant extracellular matrix settled by cancer associated fibroblasts (CAFs). Hereby, dysmetabolism and PDAC association was analyzed focusing on CAF functions.

Methods: PDAC development upon dysmetabolic conditions was investigated in: 1) high fat diet fed wild type immunocompetent syngeneic mice by orthotopic transplantation of pancreatic intraepithelial neoplasia (PanIN) organoids; and 2) primary pancreatic CAFs isolated from chemotherapy naïve PDAC patients with/without an history of metabolic syndrome.

Results: The dysmetabolic-associated higher PDAC aggressiveness was paralleled by collagen fibril enrichment due to prolyl 4-hydroxylase subunit alpha 1 (P4HA1) increased function. Upon dysmetabolism, P4HA1 boosts collagen proline hydroxylation, intensifies collagen contraction strength, precluding PDAC infiltration. Noteworthy, semaglutide, an incretin agonist, prevents the higher dysmetabolism-dependent PDAC stromal deposition and allows T lymphocyte infiltration, reducing tumor development.

Conclusions: These results shed light on novel therapeutic options for PDAC patients with metabolic syndrome aimed at PDAC stroma reshape.

Background: Glioblastoma (GBM) is a lethal brain tumor characterized by the glioma stem cell (GSC) niche. The V-ATPase proton pump has been described as a crucial factor in sustaining GSC viability and tumorigenicity. Here we studied how patients-derived GSCs rely on V-ATPase activity to sustain mitochondrial bioenergetics and cell growth.

Methods: V-ATPase activity in GSC cultures was modulated using Bafilomycin A1 (BafA1) and cell viability and metabolic traits were analyzed using live assays. The GBM patients-derived orthotopic xenografts were used as in vivo models of disease. Cell extracts, proximity-ligation assay and advanced microscopy was used to analyze subcellular presence of proteins. A metabolomic screening was performed using Biocrates p180 kit, whereas transcriptomic analysis was performed using Nanostring panels.

Results: Perturbation of V-ATPase activity reduces GSC growth in vitro and in vivo. In GSC there is a pool of V-ATPase that localize in mitochondria. At the functional level, V-ATPase inhibition in GSC induces ROS production, mitochondrial damage, while hindering mitochondrial oxidative phosphorylation and reducing protein synthesis. This metabolic rewiring is accompanied by a higher glycolytic rate and intracellular lactate accumulation, which is not exploited by GSCs for biosynthetic or survival purposes.

Conclusions: V-ATPase activity in GSC is critical for mitochondrial metabolism and cell growth. Targeting V-ATPase activity may be a novel potential vulnerability for glioblastoma treatment.