Yuan Zhu

Glioblastoma (GBM) is characterized by extensive neo-angiogenesis, which drives rapid tumor growth and therapeutic resistance. We previously identified PDCD10 as a tumor suppressor in GBM. Here, we investigated whether PDCD10 loss promotes neo-angiogenesis through paracrine signaling and GBM cell plasticity. PDCD10 knockdown (shPDCD10) enhanced endothelial angiogenic activity after treatment with conditioned medium (CM) from shPDCD10 cells and in a direct co-culture model. Moreover, application of CM to the chicken chorioallantoic membrane increased vascular branching in an in vivo angiogenesis model. Antibody array analysis detected elevated levels of multiple pro-angiogenic factors following PDCD10 depletion. In a GBM mouse model, shPDCD10 tumors exhibited pronounced hypervascularity and stromal expansion. Indeed, immunofluorescence revealed colocalization of CD31 with the tumor cell reporter RFP in a subset of implanted shPDCD10 GBM cells, suggesting that these tumor cells acquired an endothelial molecular signature. PDCD10 loss also promoted a glioma stem cell (GSC)-like phenotype, characterized by enhanced clonogenicity, sphere formation, and upregulation of Nestin, KLF4, and SOX2. Under endothelial induction conditions, shPDCD10 sphere-derived cells exhibited endothelial-like characters, showing greater tube-forming capacity and increased Ac-LDL uptake. Taken together, these findings demonstrate that PDCD10 loss promotes GBM neo-angiogenesis involving complementary paracrine and GSC-like plasticity mechanisms, highlighting PDCD10 as a potential therapeutic target to suppress neo-angiogenesis in GBM.

Glioblastoma (GBM) is an extremely invasive and incurable tumor. We previously reported predominant ALDH1A3 expression at the invasive front of GBM tumors, which was associated with shorter patient survival, and further showed that ALDH1A3 promoted tumor angiogenesis involving plasminogen activator inhibitor-1 (PAI-1). Here, we investigated whether ALDH1A3 drives cell invasion through retinoic acid (RA) and PAI-1 signaling. Analysis of the TCGA-GBM dataset revealed a positive association between ALDH1A3 and PAI-1 (SERPINE1) expression. Overexpression of ALDH1A3 in GBM cells markedly increased PAI-1 mRNA and protein levels, with cellular colocalization of both proteins, accompanied by robust migration and invasion. These effects were reversed by treatment with a pan-RA receptor (RAR) antagonist AGN193109 (AGN), with a specific PAI-1 inhibitor tiplaxtinin (Tip) or by CRISPR/Cas9-mediated knockout of PAI-1. In a chick chorioallantoic membrane (CAM) model, ALDH1A3-overexpressing cells showed increased invasion, which was reduced by tiplaxtinin (Tip) treatment or PAI-1 knockout. Mechanistically, ChIP-qPCR demonstrated that RA treatment or ALDH1A3 overexpression increased RARα occupancy at the PAI-1 regulatory region, accompanied by increased PAI-1 expression, both of which were diminished by AGN. Collectively, the present study defines an ALDH1A3-RA-PAI-1 signaling axis that contributes to GBM cell motility and invasion.

Cerebral Cavernous Malformations (CCMs) are low-flow vascular lesions located within the central nervous system, with a reported prevalence in the general population of 0.16–0.5%. Patients with CCMs may remain asymptomatic or present new onset symptoms such as seizures or focal neurological deficits often related to the occurrence of intracerebral hemorrhage. CCM may appear sporadic or as part of familial forms linked to mutations in the CCM-gene cluster, affecting endothelial cell integrity and triggering molecular cascades, including the MEKK3/KLF2/4 signaling pathway. Recent studies have highlighted the roles of inflammatory, angiogenic, and coagulation pathways alongside the emerging evidence of a gut–brain axis influencing microbiome-driven TLR4 signaling. This systematic review aims to describe molecular biomarkers associated with CCM pathophysiology, emphasizing their potential use as diagnostic and prognostic tools. Circulating plasma biomarkers such as CRP, vitamin D, and interleukins may reflect ongoing inflammatory and endothelial processes, while some imaging biomarkers like Quantitative Susceptibility Mapping (QSM) have shown a correlation with iron deposition and vascular leakage. Leveraging both circulating and imaging biomarkers may improve the therapeutic decision-making process. Further studies are encouraged to validate these findings and to facilitate the development of personalized, evidence-based strategies for the management of CCM.

Background and Objective: Cerebral cavernous malformation (CCM) is a vascular disorder causing seizures, neurological deficits, and hemorrhagic stroke. It can be sporadic or inherited via CCM1, CCM2, or CCM3 gene mutations. Inflammation is broadly recognized as a promoter of cerebral vascular malformations. This study explores inflammatory mechanisms and differences behind CCM-related hemorrhage and epilepsy. Material and Methods: The study group comprised 28 patients, ten patients with CCM-related epilepsy, and 18 patients who clinically presented with a cerebral hemorrhage at diagnosis. All patients underwent microsurgical resection of the CCMs. Formaldehyde-fixed, paraffin-embedded tissue samples were immunohistochemically stained using a monoclonal antibody against Cyclooxygenase 2 (COX-2) (Dako, Santa Clara, CA; Clone: CX-294) and NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) (ABCAM, Cambridge, MA, USA; ab214185). MRI and clinical data were correlated with immunohistochemical findings, and the analysis was conducted utilizing the Trainable Weka Segmentation algorithm. Results: Median CCM volume was 1.68 cm³ (IQR: 0.85–3.07 cm³). There were significantly more NLRP3-positive cells (32.56% to 91.98%; mean: 65.82%, median: 68.34%; SD: ±17.70%), compared to COX-2-positive cells (1.82% to 79.69%; mean: 45.87%, median: 49.06%; SD: ±22.56%). No correlation was shown between the volume of CCMs and a hemorrhage event (p = 0.13, 95% CI: 0.99–1.02). Symptomatic brain hemorrhage showed a significantly increased inflammatory enzyme upregulation from both COX-2 (p < 0.001) and NLRP3 (p = 0.009) versus patients with symptomatic CCM-related epilepsy at first diagnosis. Conclusions: Inflammatory processes in CCMs seem to be driven by broad and multiple pathways because both COX-2 and NLRP3-driven inflammatory pathways are consistently activated. As a novelty, this study showed that patients with symptomatic hemorrhage showed upregulated inflammatory enzyme activity compared to patients with CCM-related epilepsy. No direct links between NLRP3, COX-2 expression, and radiological, pathological, or preexisting patient conditions were found.

Overcoming temozolomide (TMZ)-resistance is a major challenge in glioblastoma therapy. Therefore, identifying the key molecular player in chemo-resistance becomes urgent. We previously reported the downregulation of PDCD10 in primary glioblastoma patients and its tumor suppressor-like function in glioblastoma cells. Here, we demonstrate that the loss of PDCD10 causes a significant TMZ-resistance during treatment and promotes a rapid regrowth of tumor cells after treatment. PDCD10 knockdown upregulated MGMT, a key enzyme mediating chemo-resistance in glioblastoma, accompanied by increased expression of DNA mismatch repair genes, and enabled tumor cells to evade TMZ-induced cell-cycle arrest. These findings were confirmed in independent models of PDCD10 overexpressing cells. Furthermore, PDCD10 downregulation led to the dedifferentiation of glioblastoma cells, as evidenced by increased clonogenic growth, the upregulation of glioblastoma stem cell (GSC) markers, and enhanced neurosphere formation capacity. GSCs derived from PDCD10 knockdown cells displayed stronger TMZ-resistance and regrowth potency, compared to their parental counterparts, indicating that PDCD10-induced stemness may independently contribute to tumor malignancy. These data provide evidence for a dual role of PDCD10 in tumor suppression by controlling both chemo-resistance and dedifferentiation, and highlight PDCD10 as a potential prognostic marker and target for combination therapy with TMZ in glioblastoma.

Hyper-angiogenesis is a typical feature of glioblastoma (GBM), the most aggressive brain tumor. We have reported the expression of aldehyde dehydrogenase 1A3 (ALDH1A3) in proliferating vasculature in GBM patients. We hypothesized that ALDH1A3 may act as an angiogenesis promoter in GBM. Two GBM cell lines were lentivirally transduced with either ALDH1A3 (ox) or an empty vector (ev). The angiogenesis phenotype was studied in indirect and direct co-culture of endothelial cells (ECs) with oxGBM cells (oxGBMs) and in an angiogenesis model in vivo. Angiogenesis array was performed in oxGBMs. RT²-PCR, Western blot, and double-immunofluorescence staining were performed to confirm the expression of targets identified from the array. A significantly activated angiogenesis phenotype was observed in ECs indirectly and directly co-cultured with oxGBMs and in vivo. Overexpression of ALDH1A3 (oxALDH1A3) led to a marked upregulation of PAI-1 and IL-8 mRNA and protein and a consequential increased release of both proteins. Moreover, oxALDH1A3-induced angiogenesis was abolished by the treatment of the specific inhibitors, respectively, of PAI-1 and IL-8 receptors, CXCR1/2. This study defined ALDH1A3 as a novel angiogenesis promoter. oxALDH1A3 in GBM cells stimulated EC angiogenesis via paracrine upregulation of PAI-1 and IL-8, suggesting ALDH1A3-PAI-1/IL-8 as a novel signaling for future anti-angiogenesis therapy in GBM.

Temozolomide (TMZ) is the first line of standard therapy in glioblastoma (GBM). However, relapse occurs due to TMZ resistance. We attempted to establish an acquired TMZ resistance model that recapitulates the TMZ resistance phenotype and the relevant gene signature. Two GBM cell lines received two cycles of TMZ (150 µM) treatment for 72 h each. Regrown cells (RG2) were defined as TMZ resistant cells. MTT assay revealed significantly less susceptibility and sustained growth of RG2 compared with parental cells after TMZ challenge. TMZ-induced DNA damage significantly decreased in 53BP1-foci reporter transduced-RG2 cells compared with parental cells, associated with downregulation of MSH2 and MSH6. Flow cytometry revealed reduced G2/M arrest, increased EdU incorporation and suppressed apoptosis in RG2 cells after TMZ treatment. Colony formation and neurosphere assay demonstrated enhanced clonogenicity and neurosphere formation capacity in RG2 cells, accompanied by upregulation of stem markers. Collectively, we established an acute TMZ resistance model that recapitulated key features of TMZ resistance involving impaired mismatch repair, redistribution of cell cycle phases, increased DNA replication, reduced apoptosis and enhanced self-renewal. Therefore, this model may serve as a promising research tool for studying mechanisms of TMZ resistance and for defining therapeutic approaches to GBM in the future.

We previously reported an angiogenic and tumor-suppressor-like function of programmed cell death 10 (PDCD10) in glioblastoma (GBM). However, the underlying mechanism remains to be elucidated. We hypothesized that loss of PDCD10 activates GBM cells and tumor progression via EphB4. To this end, PDCD10 was knocked down in U87 and T98g by lentiviral mediated shRNA transduction (shPDCD10). GBM cell phenotype in vitro and tumor growth in a mouse xenograft model were investigated in presence or absence of the treatment with a specific EphB4 kinase inhibitor NVP-BHG712 (NVP). We demonstrated that knockdown of PDCD10 in GBM cells significantly upregulated the mRNA and protein expression of EphB4 accompanied by the activation of Erk1/2. EphB4 kinase activity, reflected by phospho-EphB4, significantly increased in shPDCD10 GBM cells, and in tumors derived from shPDCD10 GBM xenografts, which was abolished by the treatment with NVP. Furthermore, NVP treatment significantly suppressed PDCD10-knockdown mediated aggressive GBM cell phenotype in vitro and extensive tumor cell proliferation, the tumor neo-angiogenesis, and a quick progression of tumor formation in vivo. In summary, loss of PDCD10 activates GBM cells and promotes tumor growth via triggering EphB4. Targeting EphB4 might be an effective strategy particularly for the personalized therapy in GBM patients with PDCD10-deficiency.

ALDH1A3 is a cancer stem cell marker in neoplasms including glioblastoma (GBM). However, the comprehensive role of ALDH1A3 in GBM remains unclear. This study attempted to investigate the expression of ALDH1A3 in human GBM tissues and its association with clinical parameters. Thirty primary GBM and 9 control were enrolled in this study. ALDH1A3 mRNA and protein expression levels were detected by RT2-PCR and western blot, respectively. Immunohistochemistry and immunofluorescence staining were performed to evaluate the regional and cellular expression manner of ALDH1A3. The association of ALDH1A3 expression with multiple clinical parameters was analyzed. ALDH1A3 protein level, but not mRNA level, in a subgroup of GBM was significantly higher than that in the control group. ALDH1A3 immunoreactivity was detected heterogeneously in individual GBMs. Fifteen of 30 cases showed a positive of ALDH1A3 immunoreactivity which was predominantly observed in the tumor infiltrative area (TI). Double immunofluorescence staining revealed a co-localization of ALDH1A3 with GFAP in glial-shaped cells and in tumor cells. ALDH1A3 immunoreactivity was often merged with CD44, but not with CD68. Moreover, ALDH1A3 expression was positively associated with the tumor edema grade and inversely with overall survival (OS) (median OS: 16 months vs 10 months), but with neither MGMT promoter methylation status nor Ki67 index in GBM. An upregulation of ALDH1A3 was accompanied by a reduced expression of STAT3β and p-STAT3β. Inter- and intra-tumoral heterogeneous expression of ALDH1A3 was exhibited in GBMs. A high immunoreactivity of ALDH1A3 in tumor infiltrative area was associated with shorter OS, especially in patients with MGMT promoter methylation. Our findings propose ALDH1A3 not only as a predictive biomarker but also as a potential target for personalized therapy of GBM.