Gliomas are central nervous system (CNS) derived tumors that originate from glial cells and affect six per 100,000 people in the United States. They are the most common form of CNS neoplasm and are highly diffusely infiltrative to surrounding brain tissue. Gliomas of diffusive nature are classified into different subcategories: astrocytomas, oligodendrogliomas, and ependymomas. Computed tomography (CT) and Magnetic Resonance Imaging (MRI) are used to determine tumor category and spread which may dictate treatment options. This paper focuses on emerging treatments of chemotherapy management with temozolomide and Avastin as well as emerging immune modulation treatment with vaccinations, manipulation of cellular checkpoints CTLA-4 and PD-1, co-receptor modulation of neuropilin-1, CAR-T cell therapy, and CRISPR-Cas9 gene editing. The employment of TMZ and BEV has been supported in the literature, however, more research is necessitated to fully optimize regimens and to avoid immune- and toxicity-related effects of these drugs. Moreover, an even closer consideration is warranted for current immunotherapies as they are in their infancy compared to TMZ and BEV. Thus, although promising emerging treatment options, therapies involving cancer vaccines, ICIs, immune modulation of neuropilin-1, CAR-T, and CRISPR-Cas9 technology require further investigation into their long-term efficacy and utility in treating gliomas.

Background: The front-line treatment of advanced NeuroEndocrine Neoplasms (NENs) depends on clinical and pathological factors but there are no standard second-line therapies. Methods: Metastatic NENs patients were treated at the ENETS (European NeuroEndocrine Tumor Society) center of excellence of Naples (Italy), from 2014 to 2017 with second-line metronomic temozolomide, 75 mg/m2 per os “one week on/one week off”. Toxicity was graded with NCI-CTC criteria v4.0; objective responses with RECIST v1.1 and performance status (PS) according to ECOG. Results: Twenty-six consecutive patients were treated. Median age was 65.5 years. The predominant primary organs were pancreas and lung. Grading was G2 in 11 patients, G3 in 15. Eleven patients presented with PS 1 and 15 with PS 2. The median time-on-temozolomide therapy was 12.2 months (95% CI: 11.4-19.6). No G3/G4 toxicities were registered. Complete response was obtained in 1 patient, partial response in 4, stable disease in 19 (disease control rate: 92.3%), and progressive disease in 2. The median overall survival from temozolomide start was 28.3 months. PS improved in 73% of patients. Conclusions: Metronomic temozolomide is a safe and active treatment for G2 and G3 NENs. Prospective and larger trials are needed to confirm these results.

Background. The treatment for patients with high-grade gliomas includes radiation therapy and temozolomide. However, some patients do not respond to temozolomide because they have a methylation reversal mechanism through the enzyme O6-methylguanine-DNA-methyltransferase. This biomarker has been used as a prognostic factor in patients receiving treatment with temozolomide. However, not all patients respond in the same way, which suggests the existence of other genes involved in resistance to temozolomide. Materials and Methods. A group of 31 patients with high-grade gliomas was recruited and were clinically, image pattern, and pathologically characterized. The sequencing of 324 genes related to different types of cancer was performed to detect mutations. Subsequently, a statistical analysis was conducted to determine the mutated genes that were most related to resistance to treatment. Results. The genes related to the second relapse of patients with high-grade glioma after the use of temozolomide according to Stupp protocol and metronomic dose were PIK3C2B, KIT, ERBB3, and MLH1. Conclusions. Considering the results obtained, we suggest that the mutations in the four genes and the methylation of the gene promoter that codes for MGMT protein could be related to the clinical evolution of patients with high-grade gliomas and its response to treatment with temozolomide.

Glioblastoma multiforme (GBM) is the most common high-grade intracranial tumor in adults. It is characterized by uncontrolled proliferation, diffuse infiltration due to high invasive and migratory capacities, as well as intense resistance to chemo- and radiotherapy. With a five-year survival of less than 3% and an average survival rate of 12 months after diagnosis, GBM has become a focus of current research to urgently develop new therapeutic approaches in order to prolong survival of GBM patients. The methylation status of the promoter region of the O6-methylguanine–DNA methyltransferase (MGMT) is nowadays routinely analyzed, since a methylated promoter region is beneficial for an effective response to temozolomide-based chemotherapy. Furthermore, several miRNAs were identified regulating MGMT expression, apart from promoter methylation, by degrading MGMT mRNA before protein translation. These miRNAs could be a promising innovative treatment approach to enhance Temozolomide (TMZ) sensitivity in MGMT unmethylated patients and to increase progression-free survival as well as long-term survival. In this review, the relevant miRNAs are systematically reviewed.

Glioblastomas (GBM) are most common, primary brain tumors in adults. Despite advances in neurosurgery, radio- and chemotherapy, the median survival of GBM patients is 15 months. Recent large-scale genomic, transcriptomic and epigenetic analyses have shown the cellular and molecular heterogeneity of GBMs, which hampers the outcomes of standard therapies. We have established 13 GBM-derived cell cultures from fresh tumor specimens and characterized them molecularly using RNAseq, immunoblotting and immunocytochemistry. Evaluation of proneural (OLIG2, IDH1R132H, TP53 and PDGFRα), classical (EGFR) and mesenchymal markers (CHI3L1/YKL40, CD44 and phospho-STAT3), as well as expression of pluripotency (SOX2, OLIG2, NESTIN) and differentiation (GFAP, MAP2, β-Tubulin III) markers revealed the striking inter-tumor heterogeneity of primary GBM cell cultures. Upregulated expression of VIMENTIN, N-CADHERIN and CD44 at mRNA/protein levels suggested increased epithelial to mesenchymal transition (EMT) in most studied cell cultures. The effects of temozolomide (TMZ) or doxorubicin (DOX) were tested in three GBM-derived cell cultures with different methylation status of the MGMT promoter. Amongst TMZ- or DOX-treated cultures the strongest accumulation of apoptotic markers: caspase 7 and PARP were found in WG4 cells with methylated MGMT suggesting that its methylation status predicts vulnerability to both drugs. As many GBM-derived cells showed high EGFR levels, we tested the effects of AG1478, an EGFR inhibitor, on downstream signaling pathways. AG1478 caused decreased levels of phospho-STAT3, thus inhibition of active STAT3 augmented antitumor effects of DOX and TMZ in cells with methylated and intermediate status of MGMT. Altogether, our findings show that GBM-derived cell cultures mimic the considerable tumor heterogeneity and identifying patient-specific signaling vulnerabilities can assist in overcoming therapy resistance, by providing personalized combinatorial treatment recommendations.

Glioblastoma (GBM) is the most common primary brain tumor. Due to high resistance to treatment, local invasion, and high risk of recurrence, GBM patient prognoses are often dismal, with median survival around 15 months. The current standard of care is threefold: surgery, radiation therapy and chemotherapy with temozolomide (TMZ). However, patient survival has only marginally improved. Radioimmunotherapy (RIT) is a fourth modality under clinical trials and aims at combining immunotherapeutic agents with radiotherapy. Here, we develop in vitro assays for rapid evaluation of RIT strategies. Using a standard cell irradiator and an Electric Cell Impedance Sensor, we quantify cell migration following the combination of radiotherapy and chemotherapy with TMZ and RIT with durvalumab, a PD-L1 immune checkpoint inhibitor. We measure cell survival using a cloud-based clonogenic assay. Irradiated T98G and U87 GBM cells migrate significantly (p < 0.05) more than untreated cells in the first 20-40 hours post-treatment. Addition of TMZ increased migration rates for T98G at the 20 Gy (p < 0.01). Neither TMZ nor durvalumab significantly changed cell survival in 21 days post-treatment. Interestingly, durvalumab abolished the enhanced migration effect, indicating possible potency against local invasion. These results provide parameters for rapid supplementary evaluation of RIT against brain tumors.

The CAALA (Complex Augmentation of ALA) regimen was developed with the goal of redressing some of the weaknesses of 5-aminolevulinic acid (5-ALA) use in glioblastoma treatment as it now stands. 5-ALA is approved for use prior to glioblastoma surgery to better demarcate tumor from brain tissue. 5-ALA is also used in intraoperative photodynamic treatment of glioblastoma by virtue of uptake of 5-ALA and its selective conversion to protoporphyrin IX in glioblastoma cells. Protoporphyrin IX becomes cytotoxic after exposure to 410 nm or 635 nm light. CAALA uses four currently marketed drugs - the antibiotic ciprofloxacin, the iron chelator deferiprone, the antimetabolite 5-FU, and the xanthine oxidase inhibitor febuxostat - that all have evidence of ability to both increase 5-ALA mediated intraoperative glioblastoma demarcation and photodynamic cytotoxicity of in situ glioblastoma cells. Data from testing the full CAALA on living minipigs xenotransplanted with human glioblastoma cells will determine safety and potential for benefit in advancing CAALA to a clinical trial.

The vacuolar proton translocating ATPase (V-ATPase) is a transmembrane multi-protein complex fundamental in maintaining a normal intracellular pH. In the tumoral contest, its role is crucial since the metabolism is mainly based on anaerobic glycolytic reactions. Moreover, the neoplastic cells use the V-ATPase to extrude chemotherapy drugs to the extra-cellular compartment, as a drug-resistance mechanism. In glioblastoma (GBM), the most malignant and incurable primary brain tumor, the expression of this pump is upregulated, making it a new possible therapeutic target. In this work, the bafilomycin A1 induced-inhibition of V-ATPase in patients-derived glioma stem cell (GSC) lines was evaluated together with temozolomide, the first-line line therapy against GBM. In contrast with previous published data, the proposed treatment did not overcome the resistance to the standard therapy. In addition, our data showed that nanomolar dosages of bafilomycin A1 lead to the blockage of the autophagy process and cellular necrosis, making the drug unusable in models that are more complex. Nevertheless, the increased expression of V-ATPase following bafilomycin A1 suggests a critical role of the proton pump in GBM stem component, encouraging the search for novel strategies to limit its activity in order to get around the resistance to the conventional therapy.

Cancers of the brain and nervous system account for 1 in every 100 cancer diagnoses in the United States and about 0.3 million diagnoses globally, every year. Surgery, radiotherapy, and chemo-therapy constitute the standard of care. Despite advancements in diagnosis and treatment delivery, mortality rate for these cancers have remained steady for over three decades. Immunotherapy is an emerging fourth treatment modality which has been effective against several cancers but not brain cancers, such as glioblastoma, GBM. Here, we develop in vitro assays to quantify molecular readouts of cell death, cell migration and clonogenicity, and synopsize these as biophysical markers for the rapid evaluation of immune checkpoint inhibitors (ICI), durvalumab and pembrolizumab, alone and in combination with radiotherapy (radioimmunotherapy). We find different trends in their direct action on two GBM cell lines (T98G and U87), even in the absence of immune cells. Radiation alone, and pembrolizumab with radiation, both reduced (p < 0.05) cell-cell adhesion. This reduction suggests increased potential for local invasion. Our assays offer additional insights regarding ICIs, may enable evaluation of their potential efficacy, and could set the stage for pa-tient-specific radioimmunotherapy against brain cancers, engendering improved treatment out-comes.