Journal of Experimental & Clinical Cancer Research最新文献

Background: Osteosarcoma (OS), the most prevalent primary malignant bone tumor in children and adolescents, arises from bone-forming mesenchymal cells. Despite advancements in surgical resection and neoadjuvant chemotherapy (cisplatin, doxorubicin, and methotrexate), chemotherapy resistance remains a significant challenge, leading to poor survival rates in patients with metastatic or recurrent OS.

Methods: In this study, we focused on the role of OTULIN, a key linear deubiquitinating enzyme, in OS chemoresistance. In addition, mechanistic investigations were carried out to identify potential downstream targets of OTULIN involved in cisplatin resistance.

Results: Our results demonstrated that OTULIN expression was significantly upregulated in OS tissues and cell lines following cisplatin treatment but not in response to doxorubicin or methotrexate. High OTULIN expression was associated with reduced survival in sarcoma patients. Furthermore, immunohistochemical analysis of prechemotherapy and postchemotherapy OS tissues revealed increased OTULIN expression in postchemotherapy samples. In vitro results demonstrated that OTULIN plays a critical role in mediating cisplatin resistance in OS. Mechanistically, GPX4 could be a downstream target of OTULIN, conferring cisplatin resistance to OS by blocking the mitochondrial apoptotic pathway but not ferroptosis. Specifically, OTULIN prevents the proteasomal degradation of GPX4 by reducing its ubiquitin level, thereby conferring resistance to cisplatin in OS cells.

Conclusion: This study highlights the importance of OTULIN in OS chemoresistance and provides a promising approach for targeting the OTULIN-GPX4 axis to improve the prognosis of OS patients. Our findings offer new insights into the molecular mechanisms underlying OS chemoresistance and suggest potential therapeutic targets for future clinical interventions.

Background: Head and neck squamous cell carcinoma (HNSCC) is a very aggressive disease characterized by a heterogeneous tumor immune microenvironment (TIME). Tumor-associated macrophages (TAMs) constitute the major innate immune population in the TIME where they facilitate crucial regulatory processes that participate in malignant tumor progression. SPP1 + macrophages (SPP1 + Macs) are found in many cancers, but their effects on HNSCC remain unknown. This study aimed to identify and validate the role and function of SPP1 + Macs in the malignant progression of HNSCC.

Methods: In this study, we applied single-cell RNA sequencing (scRNA-seq) analyses of paired tumor and normal tissues from 5 HNSCC patients to identify tumor-specific SPP1 + Macs. RT-qPCR and multiplex immunohistochemical and multiplex immunofluorescence staining were used to verify the presence of SPP1 + Macs in the clinical samples. Gene set variation analysis suggested that SPP1 + Macs were actively involved in cytokine production. Thus, we constructed SPP1-OE macrophages and SPP1-KD macrophages (both differentiated from THP-1 cells), performed a Luminex liquid suspension chip detection assay to detect differential cytokines, and further assessed their biological functions and mechanisms in several HNSCC cell lines and adjacent macrophages. An in vivo experiment was used to verify the function of SPP1 + Macs in HNSCC progression.

Results: The scRNA-seq results revealed that myeloid cells were heterogeneous and strongly correlated with tumor cells in the TIME in HNSCC and identified tumor-specific SPP1 + Macs, which were positively correlated with poor prognosis of HNSCC patients. Gene set variation analysis (GSVA) suggested that SPP1 + Macs were actively involved in cytokine production. Luminex liquid suspension chip detection assay indicated that SPP1 + Mac-derived TNF-α and IL-1β played important roles. Both in vitro and in vivo experiments and the use of VGX-1027, an inhibitor of macrophage-derived TNF-α and IL-1β, confirmed that SPP1 + Mac-derived TNF-α and IL-1β promoted HNSCC progression by supporting tumor cell proliferation and migration. Mechanistically, we found that TNF-α and IL-1β were upregulated due to NF-kappa B signaling pathway activation in SPP1 + Macs. Moreover, SPP1 + Mac-derived TNF-α and IL-1β promoted the expression of OPN in both tumor cells and other adjacent macrophages through different signaling pathways.

Conclusions: SPP1 + Macs increase the secretion of TNF-α and IL-1β via the NF-kappa B pathway to promote HNSCC cell proliferation, and TNF-α and IL-1β in turn upregulate the expression of OPN in tumor cells and macrophages; thus, SPP1 + Macs may be a candidate target through which antitumor efficacy can be enhanced.

Ductal carcinoma in situ (DCIS) is a noninvasive breast disease that variably progresses to invasive breast cancer (IBC). Given the unpredictability of this progression, most DCIS patients are aggressively managed similar to IBC patients. Undoubtedly, this treatment paradigm places many DCIS patients at risk of overtreatment and its significant consequences. Historically, prognostic modeling has included the assessment of clinicopathological features and genomic markers. Although these provide valuable insights into tumor biology, they remain insufficient to predict which DCIS patients will progress to IBC. Contemporary work has begun to focus on the microenvironment surrounding the ductal cells for molecular patterns that might predict progression. In this review, extracellular microenvironment alterations occurring with the malignant transformation from DCIS to IBC are detailed. Not only do changes in collagen abundance, organization, and localization mediate the transition to IBC, but also the discrete post-translational regulation of collagen fibers is understood to promote invasion. Other extracellular matrix proteins, such as matrix metalloproteases, decorin, and tenascin C, have been characterized for their role in invasive transformation and further demonstrate the prognostic value of the extracellular matrix. Importantly, these extracellular matrix proteins influence immune cells and fibroblasts toward pro-tumorigenic phenotypes. Thus, the progressive changes in the extracellular microenvironment play a key role in invasion and provide promise for prognostic development.

Background: Malignant pleural mesothelioma (MPM) is a highly chemo-refractory and immune-evasive tumor that presents a median overall survival of 12-14 months when treated with chemotherapy and immunotherapy. New anti-tumor therapies as well as the concomitant reactivation of immune destruction are urgently needed to treat patients with this tumor. The aim of this work is to investigate the potential effect of ecteinascidin derivatives as lurbinectedin as new first-line treatment option in MPM, alone and in combination with immunotherapy.

Methods: The antitumor activity of ecteinascidin synthetic analogues: lurbinectedin, ecubectedin and PM54 was evaluated in an array of patient-derived MPM cells in terms of cell proliferation, cell cycle, apoptosis, DNA damage and repair. Immunoblot was used to assess the cGAS/STING pathway. ELISA and flow cytometry-based assays were used to evaluate immunogenic cell death parameters and the effect on the immunophenotype in autologous peripheral blood monocyte-MPM cells co-cultures. Patient-derived xenografts (PDX) in humanized mice were used to evaluate the efficacy of ecteinascidins in vivo.

Results: Lurbinectedin, ecubectedin, and PM54 were effective in reducing cell proliferation and migration, as well as inducing S-phase cell cycle arrest and DNA damage in malignant pleural mesothelioma cells. These effects were more pronounced compared to the standard first-line treatment (platinum-based plus pemetrexed). Mechanistically, the drugs downregulated DNA repair genes, activated the cGAS/STING pathway, and promoted the release of pro-inflammatory cytokines. They also induced immunogenic cell death of mesothelioma cells, enhancing the activation of anti-tumor CD8⁺T-cells and natural killer cells while reducing tumor-tolerant T-regulatory cells and myeloid-derived suppressor cells in ex vivo co-cultures. These promising results were also observed in humanized patient-derived xenograft models, where the drugs were effective in reducing tumor growth and increasing the ratio anti-tumor/pro-tumor infiltrating immune populations, either alone or combined with the anti-PD-1L atezolizumab.

Conclusions: Collectively, these findings reveal a previously unknown mechanism of action of ecteinascidins that merits further investigation for potential clinical applications in the treatment of MPM, as new first line treatment in monotherapy or in association with immunotherapy.

Cancer-associated fibroblasts (CAFs) represent a group of genotypically non-malignant stromal cells in the tumor micro-environment (TME) of solid tumors that encompasses up to 80% of the tumor volume. Even though the phenotypic diversity and plasticity of CAFs complicates research, it is well-established that CAFs can affect many aspects of tumor progression, including growth, invasion and therapy resistance. Although anti-tumorigenic properties of CAFs have been reported, the majority of research demonstrates a pro-tumorigenic role for CAFs via (in)direct signaling to cancer cells, immunomodulation and extracellular matrix (ECM) remodeling. Following harsh therapeutic approaches such as radio- and/or chemotherapy, CAFs do not die but rather become senescent. Upon conversion towards senescence, many pro-tumorigenic characteristics of CAFs are preserved or even amplified. Senescent CAFs continue to promote tumor cell therapy resistance, modulate the ECM, stimulate epithelial-to-mesenchymal transition (EMT) and induce immunosuppression. Consequently, CAFs play a significant role in tumor cell survival, relapse and potentially malignant transformation of surviving cancer cells following therapy. Modulating CAF functioning in the TME therefore is a critical area of research. Proposed strategies to enhance therapeutic efficacy include reverting senescent CAFs towards a quiescent phenotype or selectively targeting (non-)senescent CAFs. In this review, we discuss CAF functioning in the TME before and during therapy, with a strong focus on radiotherapy. In the future, CAF functioning in the therapeutic TME should be taken into account when designing treatment plans and new therapeutic approaches.

Background: Thymic epithelial tumors (TETs) are infrequent malignancies that arise from the anterior mediastinum. Therapeutic options for TETs, especially thymic carcinoma (TC), remain relatively constrained. This study aims to investigate the oncogenic hub gene and its underlying mechanisms in TETs, as well as to identify potential therapeutic targets.

Methods: Weighted gene co-expression network analysis (WGCNA) and differential gene expression (DEG) analysis were utilized to identify significant oncogenes using The Cancer Genome Atlas (TCGA) database. LASSO logistic regression analysis was performed to assess the association between hub genes and clinical parameters. The influence of the hub gene on promoting epithelial-mesenchymal transition (EMT), tumor progression, and regulating cancer stem cell-like properties was assessed both in vitro and in vivo. Single-cell RNA sequencing (scRNA-seq) was utilized to analyze the alterations in the tumor and its microenvironment following the administration of the hub gene's inhibitor. Multiplex immunohistochemistry (mIHC) was employed to validate the results. The potential mechanism was further elucidated through the utilization of Cleavage Under Targets and Tagmentation (CUT&Tag), RNA-sequencing, chromatin immunoprecipitation (ChIP), CUT&RUN, luciferase reporter assay, co-immunoprecipitation (Co-IP), mass spectrometry (MS) and phosphoproteomic assays.

Results: SNAI1 was identified as a hub transcription factor for TETs, and its positive correlation with the invasiveness of the disease was confirmed. Subsequent experiments revealed that the upregulation of SNAI1 augmented the migration, invasion, and EMT of TET cell lines. Furthermore, we observed that the overexpression of SNAI1 sustained cancer stem cell-like properties. ScRNA-seq demonstrated that the use of a SNAI1 inhibitor inhibited the transition of macrophages from M1 to M2 phenotype, a finding further validated by multiplex immunohistochemistry (mIHC). Phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) was identified as one of the downstream targets of SNAI1 through CUT&Tag and RNA-sequencing, a finding validated by ChIP-qPCR, CUT&RUN-qPCR, luciferase reporter and immunofluorescence assays. Co-IP, MS and phosphoproteomic assays further confirmed that PIK3R2 directly interacted with phosphorylated EphA2 (p-EphA2), facilitating downstream GSK3β/β-catenin signaling pathway.

Conclusion: The tumorigenic role of SNAI1 through the PIK3R2/p-EphA2 axis was preliminarily validated in TETs. A potential therapeutic strategy for TETs may involve the inhibition of SNAI1.

Background: Mitochondrial DNA (mtDNA) pathogenic variants have been reported in several solid tumors including ovarian cancer (OC), the most lethal gynecologic malignancy, and raised interest as they potentially induce mitochondrial dysfunction and rewiring of cellular metabolism. Despite advances in recent years, functional characterization of mtDNA variants in cancer and their possible modulation of drug response remain largely uncharted.

Methods: Here, we characterized mtDNA variants in OC patient derived xenografts (PDX) and investigated their impact on cancer cells at multiple levels.

Results: Genetic analysis revealed that mtDNA variants predicted as pathogenic, mainly involving complex I and IV genes, were present in all but one PDX (n = 20) at different levels of heteroplasmy, including 7 PDXs with homoplasmic variants. Functional analyses demonstrated that pathogenic mtDNA variants impacted on respiratory complexes activity and subunits abundance as well as on mitochondrial morphology. Moreover, PDX cells bearing homoplasmic mtDNA variants behaved as glucose-addicted and could barely survive glucose starvation in vitro. RNA-seq analysis indicated that mtDNA mutated (heteroplasmy > 50%) PDXs were endowed with upregulated glycolysis and other pathways connected with cancer metabolism. These findings led us to investigate whether pathogenic mtDNA variants correlated with response to anti-VEGF therapy, since the latter was shown to reduce glucose availability in tumors. Strikingly, PDXs bearing homoplasmic pathogenic mtDNA variants associated with improved survival upon anti-VEGF treatment in mice, compared with mtDNA wild type or low heteroplasmy PDXs.

Conclusions: These results hint at mtDNA variants as potential biomarkers of response to antiangiogenic drugs.

Background: The immune landscape associated with different subtypes of intestinal metaplasia (IM) and early gastric cancer (EGC) remains unclear. This study aimed to investigate the immune landscape of complete intestinal metaplasia (CIM), incomplete intestinal metaplasia (IIM), and EGC, as well as the underlying mechanisms of EGC progression.

Methods: Gastric biopsy samples were collected from five patients with CIM, six patients with IIM, and four patients with EGC, followed by single-cell RNA sequencing. Multiplex immunohistochemical staining was employed to validate the samples from the aforementioned patients. To elucidate the potential mechanisms involved, in vitro coculture experiments were conducted using FOLR2⁺/FOLR2^- macrophages and CD8⁺ T cells. Flow cytometry was utilized to investigate the biological functions of FOLR2⁺ macrophages in the progression of EGC.

Results: Five subpopulations of macrophages were identified in CIM, IIM and EGC samples. FOLR2⁺ macrophages possess antitumor immune potential, and the proportion of FOLR2⁺ macrophage gradually decreased from the CIM stage to the IIM and EGC stages. FOLR2⁺ macrophages were significantly positively correlated with CD8⁺ T cells and activated the cytotoxicity of CD8⁺ T cells via antigen cross-presentation. Additionally, during the progression of EGC, epithelial cells progressively upregulated APP expression, thus inducing necroptosis of FOLR2⁺ macrophages via the APP‒TNFRSF21 axis.

Conclusions: Our work provides an understanding of the potential mechanisms underlying the malignant transformation of IM mediated by FOLR2⁺ macrophages.

Multiple myeloma (MM), a hematologic malignancy characterized by the clonal expansion of plasma cells within the bone marrow, is associated with severe health complications, including osteolytic bone lesions that significantly increase the risk of fractures, leading to higher morbidity and mortality rates. One intriguing protein in this context is the RNA polymerase binding factor Che-1/AATF (Che-1), which has emerged as a potential player in the survival and proliferation of myeloma cells. Hippo pathway has been shown to be an important mediator of oncogenesis in solid tumors, especially for its role in shaping a tumor microenvironment favorable to cancer maintenance and spread. The Hippo pathway is also implicated in the pathogenesis of the osteolytic lesions that occurs in MM, since it deregulates the activities of mesenchymal populations of the bone matrix. In this commentary we wish to highlight some new molecular aspects elucidated in the paper by Bruno et al. regarding the proliferation of MM and the onset of bone lesions [Leukemia 38:877-882, 1]. A series of recent findings has revealed a crosstalk between the RNA polymerase binding factor Che-1 and the HIPPO downstream co-transcriptional factor TAZ, bringing to light new emerging molecular targets in MM to limit the development of bone lesions.