Leptomeningeal metastasis (LM) has a poor prognosis and is difficult to diagnose and predict the response of treatment. In this study, we suggested that the monitoring of changes in the concentration of extracellular vesicles in cerebrospinal fluid could help diagnose or predict outcomes for LM. We measured nanoparticles in 472 human cerebrospinal fluid (CSF) from patients including LM with both Dynamic Light Scattering (DLS) and Nanoparticle Tracking Analysis (NTA) after two-step centrifugations. NTA revealed that the concentration of CSF nanoparticles was significantly increased in LM compared to other groups (2.80 × 10⁸ /mL vs. 1.49 × 10⁸ /mL, p < 0.01). Changes in NTA-measured nanoparticles concentration after intra-CSF chemotherapy were further examined in 33 non-small cell lung cancer patients with LM. Overall survival was longer for patients with increased EV than the others (442 vs. 165 days, p < 0.001). Markers of extracellular vesicles (CD9/CD63/CD81) significantly decreased in the EV-decreased group. MicroRNA-21 expression decreased in this favorable prognostic group, whereas it increased in the EV-decreased group. In conclusion, the elevated concentration of extracellular vesicles in cerebrospinal fluid in patients with LM may be a predictive marker for survival duration. Moreover, EV changes combined with microRNA-21 might be a biomarker for monitoring the efficacy of intracranial chemotherapy of LM in non-small cell lung cancer patients.

Phosphoserine phosphatase (PSPH) is one of the key enzymes of the L-serine synthesis pathway. PSPH is reported to affect the progression and survival of several cancers in an L-serine synthesis-independent manner, but the mechanism remains elusive. We demonstrate that PSPH promotes lung cancer progression through a noncanonical L-serine-independent pathway. PSPH was significantly associated with the prognosis of lung cancer patients and regulated the invasion and colony formation of lung cancer cells. Interestingly, L-serine had no effect on the altered invasion and colony formation by PSPH. Upon measuring the phosphatase activity of PSPH on a serine-phosphorylated peptide, we found that PSPH dephosphorylated phospho-serine in peptide sequences. To identify the target proteins of PSPH, we analyzed the protein phosphorylation profile and the PSPH-interacting protein profile using proteomic analyses and found one putative target protein, IRS-1. Immunoprecipitation and immunoblot assays validated a specific interaction between PSPH and IRS-1 and the dephosphorylation of phospho-IRS-1 by PSPH in lung cancer cells. We suggest that the specific interaction and dephosphorylation activity of PSPH have novel therapeutic potential for lung cancer treatment, while the metabolic activity of PSPH, as a therapeutic target, is controversial.

Glioblastoma stem cells (GSCs) are pivotal in the recurrence and drug resistance of glioblastoma multiforme (GBM). However, precision therapeutic and diagnostic markers for GSCs have not been fully established. Here, using bioinformatics and experimental analysis, we identified P4HB, a protein disulfide isomerase, as a serum marker that maintains stemness in GSCs through the Wnt/β-catenin signaling pathway. Transcriptional silencing of P4HB induces apoptosis and diminishes stem cell-like characteristics in GSCs. Treatments with the chemical CCF624 or the China National Medical Products Administration (NMPA)-approved securinine significantly prolonged survival in patient-derived xenograft mouse models, underscoring P4HB’s potential as a therapeutic target and presenting an expedited path to clinical application through drug repurposing. Additionally, elevated P4HB levels in patient serum were found to correlate with disease progression, underscoring its utility as a biomarker and its promise for precision medicine.

The diagnosis of leptomeningeal metastasis (LM) is often difficult due to the paucity of cancer cells in cerebrospinal fluid (CSF) and nonspecific findings on neuroimaging. Investigations of extracellular microRNAs (miRNAs) in CSF could be used for both the diagnosis and study of LM pathogenesis because they reflect the activity of disseminating cancer cells. We isolated CSF extracellular miRNAs from patients (n = 65) of different central nervous system tumor statuses, including cancer control, healthy control, LM, brain metastasis (BM), and primary brain tumor (BT) groups, and performed miRNA microarrays. In unsupervised clustering analyses, all LM and two BM samples showed unique profiles. Among 30 miRNAs identified for LM-specific biomarkers via a Prediction Analysis of Microarrays, miR-335-5p and miR-34b-3p were confirmed in both the discovery and validation samples (n = 23). Next, we performed a significance analysis of the microarray (SAM) to extract discriminative miRNA profiles of two selected CSF groups, with LM samples revealing a greater number of discriminative miRNAs than BM and BT samples compared to controls. Using SAM comparisons between LM and BM samples, we identified 30 upregulated and 6 downregulated LM miRNAs. To reduce bias from different primary cancers, we performed a subset analysis with primary non-small cell lung cancer, and 12 of 13 upregulated miRNAs in LM vs. BM belonged to the upregulated miRNAs in LM. We identified possible target genes and their biological processes that could be affected by LM discriminative miRNAs in NSCLC using the gene ontology database. In conclusion, we identified a unique extracellular miRNA profile in LM CSF that was different from BM, suggesting the use of miRNAs as LM biomarkers in studies of LM pathogenesis.

Hepatocellular carcinoma (HCC) remains one of the most aggressive and lethal malignancies worldwide, with high rates of metastasis and recurrence contributing to its poor prognosis. There is an urgent need to elucidate the molecular mechanisms driving HCC progression and to develop effective therapeutic strategies. Metabolic reprogramming, especially aerobic glycolysis known as the Warburg effect, is a well-established hallmark of cancer. Concurrently, cancer stem cells (CSCs) play crucial roles in tumor initiation, therapy resistance, and recurrence. However, the involvement of long non-coding RNAs (lncRNAs) in linking metabolic alterations and stemness remains poorly understood. In this investigation, we identified LINC02041 as a significantly upregulated lncRNA in HCC tissues and demonstrated its oncogenic role in promoting cell proliferation. We found that STAT3 transcriptionally activates LINC02041 expression. Mechanistically, LINC02041 enhances the stability of SRSF1 protein by suppressing its ubiquitin-mediated degradation, thereby facilitating HCC cell proliferation, migration, glycolytic metabolism, and acquisition of stem-like properties. Our findings delineate a novel STAT3/LINC02041/SRSF1 regulatory axis that coordinately modulates glycolytic reprogramming and stemness maintenance in hepatocarcinogenesis. This study not only advances our understanding of HCC pathophysiology but also identifies LINC02041 as a promising prognostic biomarker and a compelling therapeutic target for novel therapeutic strategies against this aggressive malignancy.