Background: Glioblastoma multiforme (GBM) is the most aggressive type of glioma and carries the poorest chances of survival. There is therefore an urgent need to understand the mechanisms of glioma tumorigenesis and develop or improve therapeutics. The aim of this study was to assess the possible prognostic value of cyclin-dependent kinase 6 (CDK6) and the effects of microRNA-495 (miR-495) manipulation on CDK6 expression and cell survival in glioma cells. Methods: Analyses of clinical specimens from GBM patients were used. Expression of CDK6 was analyzed by real-time polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry. Expression of CDK6 was also analyzed after over-expression of miR-495 in T98 cells; both cell proliferation and RB phosphorylation were examined. Cell proliferation, cell cycle distribution, and RB phosphorylation were also examined after knockdown of CDK6 in U87-MG and T98 cells. Results: Analyses of clinical specimens from GBM patients identified that CDK6 is significantly expressed in gliomas. CDK6 antigen expression was higher in tumor cores and margins than in adjacent normal brain tissues, and higher levels of CDK6 expression in the tumor margin correlated with decreased survival. Over-expression of miR-495 in T98 cells downregulated the expression of CDK6 and inhibited retinoblastoma phosphorylation, and knockdown of CDK6 in U87-MG and T98 cells by siRNAs resulted in cell cycle arrest at the G1/S transition and inhibition of cell proliferation. Conclusions: This study revealed miR-495 is down-regulated in glioma tissues. Furthermore, miR-495 regulated CDK6 expression and involved in glioma cell growth inhibition, which indicated the possible role of miR-495 in tumor progression.

Sonodynamic therapy (SDT) is a novel tumor treatment that combines biosafe sonosensitizers and noninvasive focused ultrasound to eradicate solid tumors. Sonosensitizers such as 5-aminolevulinic acid and fluorescein have great potential in tumor treatment. Here, rodent subcutaneous and brain tumor models were used to evaluate the treatment effect of both 5-ALA- and fluorescein-mediated SDT. The subcutaneous tumor growth rates of both SDT groups were significantly inhibited compared with that of the control groups. For intracranial tumors, 5-ALA-SDT treatment significantly inhibited brain tumor growth, while fluorescein-SDT exerted no therapeutic effect in animals. The distribution of fluorescein in the brain tumor region underwent further assessment. Seven days post tumor implantation, experimental animals received fluorescein and were sacrificed for brain specimen collection. Analysis of the dissected brains revealed no fluorescence signals, indicating an absence of fluorescein accumulation in the early-stage glioma tissue. These data suggest that the fluorescein-SDT treatment response is closely related to the amount of accumulated fluorescein. This study reports the equivalent effects of 5-ALA and fluorescein on the treatment of somatic tumors. For orthotopic brain tumor models, tumor vascular permeability should be considered when choosing fluorescein as a sonosensitizer. In conclusion, both fluorescein and 5-ALA are safe and effective SDT sonosensitizers, and the tumor microenvironment and pathologic type should be considered in the selection of adequate sonosensitizers.

BACKGROUND AND OBJECTIVES: Combining focused ultrasound (FUS)–induced blood-brain barrier opening with bevacizumab (BEV) has demonstrated survival benefits in preclinical models. This study aimed to evaluate the safety and feasibility of repeated FUS-BEV treatments in patients with recurrent glioblastoma and to explore imaging and serum biomarkers in relation to disease status. METHODS: This was a prospective, single-arm, open-label pilot trial. The primary end point was 6-month progression-free survival (PFS). Disease progression was assessed according to the Response Assessment in Neuro-Oncology criteria by independent radiological review. Radiological response was evaluated using fluid-attenuated inversion-recovery sequences to compare FUS-exposed vs nonexposed regions. Plasma cell–free DNA (cfDNA) concentrations were measured before and after FUS treatment. RESULTS: Between July 2020 and August 2023, 6 patients received a median of 14.5 sessions of biweekly FUS-BEV (10 mg/kg). The median PFS was 11 months, with a 6-month PFS rate of 66.7%. The only FUS-related adverse event was transient scalp heating (grade 1; 1.9%). A fluid-attenuated inversion recovery normalization effect emerged within 1 month after treatment. Plasma cfDNA increased significantly post-FUS, with total cfDNA rising 2.03 ± 0.76-fold, EGFR cfDNA 1.77 ± 0.76-fold, and HMBS cfDNA 1.68 ± 0.66-fold. CONCLUSION: Repeated FUS-BEV treatment is safe and feasible in patients with recurrent glioblastoma. Randomized controlled trials are warranted to confirm its therapeutic efficacy and validate imaging and liquid biopsy biomarkers.