Effect of Polyunsaturated Fatty Acids on Temozolomide Drug-Sensitive and Drug-Resistant Glioblastoma Cells

Clusterin-mediated polarization of M2 macrophages: a mechanism of temozolomide resistance in glioblastoma stem cells

Glioblastoma remains one of the most lethal malignancies, largely due to its resistance to standard chemotherapy such as temozolomide. This study investigates a novel resistance mechanism involving glioblastoma stem cells (GSCs) and the polarization of M2-type macrophages, mediated by the extracellular vesicle (EV)-based transfer of Clusterin. Using 6-week-old male CD34+ humanized huHSC-(M-NSG) mice (NM-NSG-017) and glioblastoma cell lines (T98G and U251), we demonstrated that GSC-derived EVs enriched with Clusterin induce M2 macrophage polarization, thereby enhancing temozolomide resistance in glioblastoma cells. Single-cell and transcriptome sequencing revealed close interactions between GSCs and M2 macrophages, highlighting Clusterin as a key mediator. Our findings indicate that Clusterin-rich EVs from GSCs drive glioblastoma cell proliferation and resistance to temozolomide by modulating macrophage phenotypes. Targeting this pathway could potentially reverse resistance mechanisms, offering a promising therapeutic approach for glioblastoma. This study not only sheds light on a critical pathway underpinning glioblastoma resistance but also lays the groundwork for developing therapies targeting the tumor microenvironment. Our results suggest a paradigm shift in understanding glioblastoma resistance, emphasizing the therapeutic potential of disrupting EV-mediated communication in the tumor microenvironment.

Construction of a prognostic signature for breast cancer based on genes involved in unsaturated fatty acid biosynthesis

Background

The biosynthesis of unsaturated fatty acids (UFAs) has been implicated in the onset and advancement of breast cancer (BC). This study aimed to develop molecular subtypes and prognostic signatures for BC based on UFA-related genes (UFAGs).

Methods

This study integrates multi-omics and survival data from public databases to elucidate molecular classifications and risk profiles based on UFAGs. Consensus clustering and Lasso Cox regression methodologies are employed for subtype identification and risk signature development, respectively. Immune microenvironment assessment is conducted using CIBERSORT and ESTIMATE algorithms, while drug sensitivity and response to immunotherapy are evaluated via pRRophetic and TIDE methods. Gene set enrichment analysis augments signature characterization, followed by nomogram construction and validation.

Results

We successfully identified two distinct BC molecular subtypes with significantly different prognoses utilizing UFAGs correlated with outcomes. A prognostic signature comprising three UFAGs [acetyl-CoA acyltransferase 1 (ACAA1), acyl-CoA thioesterase 2 (ACOT2), and ELOVL fatty acid elongase 2 (ELOVL2)] is developed, stratifying patients into high- and low-risk groups exhibiting divergent outcomes, clinicopathological traits, gene expression patterns, immune infiltration profiles, therapeutic susceptibility, and immunotherapy responses. The signature demonstrates robust prognostic performance in both training and validation cohorts, emerging as an independent predictor alongside age, which is integrated into a nomogram. Decision curve analysis highlights the nomogram's superiority over other factors in prognosis prediction. Calibration plots and receiver operating characteristic curves affirm its excellent performance in BC prognosis assessment.

Conclusions

Expression profiles of UFAGs are associated with BC prognosis, enabling the creation of a risk signature with implications for understanding the molecular mechanisms underlying BC progression.

Lipoxygenases at the Intersection of Infection and Carcinogenesis

The persisting presence of opportunistic pathogens like Pseudomonas aeruginosa poses a significant threat to many immunocompromised cancer patients with pulmonary infections. This review highlights the complexity of interactions in the host's defensive eicosanoid signaling network and its hijacking by pathogenic bacteria to their own advantage. Human lipoxygenases (ALOXs) and their mouse counterparts are integral elements of the innate immune system, mostly operating in the pro-inflammatory mode. Taking into account the indispensable role of inflammation in carcinogenesis, lipoxygenases have counteracting roles in this process. In addition to describing the structure-function of lipoxygenases in this review, we discuss their roles in such critical processes as cancer cell signaling, metastases, death of cancer and immune cells through ferroptosis, as well as the roles of ALOXs in carcinogenesis promoted by pathogenic infections. Finally, we discuss perspectives of novel oncotherapeutic approaches to harness lipoxygenase signaling in tumors.

Fibronectin Type III Domain Containing 3B as a Potential Prognostic and Therapeutic Biomarker for Glioblastoma

Glioblastoma (GBM) is a representative malignant brain tumor characterized by a dismal prognosis, with survival rates of less than 2 years and high recurrence rates. Despite surgical resection and several alternative treatments, GBM remains a refractory disease due to its aggressive invasiveness and resistance to anticancer therapy. In this report, we explore the role of fibronectin type III domain containing 3B (FNDC3B) and its potential as a prognostic and therapeutic biomarker in GBM. GBM exhibited a significantly higher cancer-to-normal ratio compared to other organs, and patients with high FNDC3B expression had a poor prognosis (p < 0.01). In vitro studies revealed that silencing FNDC3B significantly reduced the expression of Survivin, an apoptosis inhibitor, and also reduced cell migration, invasion, extracellular matrix adhesion ability, and stem cell properties in GBM cells. Furthermore, we identified that FNDC3B regulates PTEN/PI3K/Akt signaling in GBM cells using MetaCore integrated pathway bioinformatics analysis and a proteome profiler phospho-kinase array with sequential western blot analysis. Collectively, our findings suggest FNDC3B as a potential biomarker for predicting GBM patient survival and for the development of treatment strategies for GBM.