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Background In malignant glioma (MG) patients undergoing radiation therapy (RT) with concomitant temozolomide, chemoradiation-induced nausea and vomiting (cRINV) degrades quality of life (QoL) and reduces treatment adherence, which thereby potentially compromises cancer control. Methods We conducted a 6-week phase II single-arm trial of PAL, a second-generation 5-HT 3 RA antiemetic, for cRINV prevention in MG patients receiving radiation therapy (RT; 54–60 Gy) and concomitant daily temozolomide (TMZ; 75 mg/m 2 /dX42d). Each week before radiation, patients received single-dose palonosetron (PAL) 0.25 mg IV (total = 6 doses). With safety/tolerability as the primary endpoint, the study was designed to differentiate between toxicity rates of 25 % (unacceptable) and 10 % (acceptable) toxicity rates. Secondary endpoints included the percentage of patients achieving cRINV complete response (CR: no emesis or rescue antiemetic) and QoL. Patients reported adverse effects in Common Toxicity Criteria for Adverse Events diaries; recorded vomiting, nausea, and rescue medication use in diaries (which were used to assess cRINV-CR); and reported QoL 4 days/week using the Modified Functional Living Index-Emesis (M-FLIE) and Osoba nausea and vomiting/retching modules. Results We enrolled 38 patients (mean age 59 years, 55 % female, 95 % white, 68 % used oral corticosteroids, 76 % reported low alcohol use). Four patients (10.5 %) experienced unacceptable treatment-related toxicity, defined as any grade 3, 4, or 5 non-hematologic toxicity. M-FLIE and Osoba scores showed no evidence of treatment impact on QoL. Overall, cRINV-CR rates for 6 weeks ranged from 67–79 %. Conclusion Single-dose weekly PAL is a safe and tolerable antiemetic for cRINV prevention in MG patients receiving standard RT and concomitant TMZ.

A recent phase 1/2 clinical trial argued for caution for the use of sulfasalazine in progressive glioblastoma (GBM). However, the study enrolled patients with recurrent or progressive high-grade glioma indicating that patients recruited probably had severe disease. Thus, the study may not accurately reflect the effectiveness of sulfasalazine for GBM and we hypothesized that earlier sulfasalazine administration may lead to anticancer effects. The aim of this study was to investigate whether sulfasalazine can improve the outcomes of patients with newly diagnosed GBM. A total of 12 patients were treated with temozolomide and sulfasalazine with radiation therapy after surgery. Twelve patients with primary GBM treated with temozolomide and radiation therapy formed the control group. Progression-free survival (PFS), overall survival (OS) and seizure-free survival (SFS) curves were obtained using the Kaplan-Meier method. The survival curves were compared using the log-rank test. The median OS, PFS and SFS did not differ between the groups. Grade 3 or 4 adverse events occurred over the duration of the study in nine (75%) patients. The median SFS was 12 months in nine patients who received sulfasalazine administration for more than 21 days, which was strongly but not significantly longer than the 3 months observed in the control group (P = 0.078). Sulfasalazine treatment with temozolomide plus radiotherapy for newly diagnosed primary GBM is associated with a high rate of discontinuation due to hematologic toxic effects. This treatment may have no effect on OS or PFS, although it may improve seizure control if an adequate dose can be administered.

By using a GFP reporter protein expressed selectively in neural stem cells in a mouse model of glioblastoma, a small subset of GFP-positive glioma cells is shown to be responsible for re-growth of tumours after chemotherapy. A cancer-cell hierarchy In a mouse model of glioblastoma, Luis Parada and colleagues use a green fluorescent protein (GFP) reporter protein expressed selectively in neural stem cells — in which the tumours arise — to trace cancer cells in an endogenous setting. The reporter labelled a small subset of glioma cells that were less proliferative than the bulk of the tumour cells. However, the GFP + cells were responsible for re-growth of the tumours after treatment with the cytotoxic drug temozolomide. Selective ablation of the GFP + cells combined with temozolomide was more effective at arresting tumour growth. The GFP + cells appear to be at the apex of a functional hierarchy of cancer cells so may represent cancer stem cells — a subset of tumour cells able to maintain tumour growth. Targeting both this population and the more proliferative bulk of cancer cells may lead to improved therapeutic outcome. Glioblastoma multiforme is the most common primary malignant brain tumour, with a median survival of about one year 1 . This poor prognosis is due to therapeutic resistance and tumour recurrence after surgical removal. Precisely how recurrence occurs is unknown. Using a genetically engineered mouse model of glioma, here we identify a subset of endogenous tumour cells that are the source of new tumour cells after the drug temozolomide (TMZ) is administered to transiently arrest tumour growth. A nestin-ΔTK-IRES-GFP ( Nes-ΔTK-GFP ) transgene that labels quiescent subventricular zone adult neural stem cells also labels a subset of endogenous glioma tumour cells. On arrest of tumour cell proliferation with TMZ, pulse-chase experiments demonstrate a tumour re-growth cell hierarchy originating with the Nes-ΔTK-GFP transgene subpopulation. Ablation of the GFP + cells with chronic ganciclovir administration significantly arrested tumour growth, and combined TMZ and ganciclovir treatment impeded tumour development. Thus, a relatively quiescent subset of endogenous glioma cells, with properties similar to those proposed for cancer stem cells, is responsible for sustaining long-term tumour growth through the production of transient populations of highly proliferative cells.

Real-time monitoring of drug efficacy in glioblastoma multiforme (GBM) is a major clinical problem as serial re-biopsy of primary tumours is often not a clinical option. MGMT (O 6 -methylguanine DNA methyltransferase) and APNG (alkylpurine-DNA-N-glycosylase) are key enzymes capable of repairing temozolomide-induced DNA damages and their levels in tissue are inversely related to treatment efficacy. Yet, serial clinical analysis remains difficult, and, when done, primarily relies on promoter methylation studies of tumour biopsy material at the time of initial surgery. Here we present a microfluidic chip to analyse mRNA levels of MGMT and APNG in enriched tumour exosomes obtained from blood. We show that exosomal mRNA levels of these enzymes correlate well with levels found in parental cells and that levels change considerably during treatment of seven patients. We propose that if validated on a larger cohort of patients, the method may be used to predict drug response in GBM patients. Predicting and monitoring chemotherapy response remains a challenge for glioma treatment. Here the authors show that a microfluidic device can isolate glioma-derived exosomes from patient blood and accurately determine the levels of mRNA of key enzymes important for chemoresponsiveness.

Drug combination represents one of the most accredited strategies of cancer therapy able to improve drug efficacy and possibly overcome drug resistance. Among the agents used to complement conventional chemotherapy, carbonic anhydrase IX (CAIX) inhibitors appear as one of the most suitable, as markers of hypoxic and acidic cancer cells which do not respond to chemo- and radiotherapy. We performed preclinical in vitro assays to evaluate whether the SLC-0111 CAIX inhibitor co-operates and potentiates the cytotoxic effects of conventional chemotherapeutic drugs in A375-M6 melanoma cells, MCF7 breast cancer cells, and HCT116 colorectal cancer cells. Here, we demonstrate that the SLC-0111 CAIX inhibitor potentiates cytotoxicity of Dacarbazine and Temozolomide currently used for advanced melanoma treatment. SLC-0111 also increases breast cancer cell response to Doxorubicin and enhances 5-Fluorouracil cytostatic activity on colon cancer cells. These findings disclose the possibility to extend the use of CAIX inhibitors in the combination therapy of various cancer histotypes.

The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) is commonly overexpressed in cancers and is implicated in the development of chemoresistance. The use of drugs inhibiting MGMT has been hindered by their haematologic toxicity and inefficiency. As a different strategy to inhibit MGMT we investigated cellular regulators of MGMT expression in multiple cancers. Here we show a significant correlation between Wnt signalling and MGMT expression in cancers with different origin and confirm the findings by bioinformatic analysis and immunofluorescence. We demonstrate Wnt-dependent MGMT gene expression and cellular co-localization between active β-catenin and MGMT. Pharmacological or genetic inhibition of Wnt activity downregulates MGMT expression and restores chemosensitivity of DNA-alkylating drugs in mouse models. These findings have potential therapeutic implications for chemoresistant cancers, especially of brain tumours where the use of temozolomide is frequently used in treatment. The high expression of the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT) often confers resistance to chemotherapy in several cancers. In this study, the authors propose the inhibition of the Wnt signalling pathway as an alternative strategy to modulate MGMT expression and sensitize tumours to chemotherapy.

Glioblastoma multiforme patients have a poor prognosis due to therapeutic resistance and tumor relapse. It has been suggested that gliomas are driven by a rare subset of tumor cells known as glioma stem cells (GSCs). This hypothesis states that only a few GSCs are able to divide, differentiate, and initiate a new tumor. It has also been shown that this subpopulation is more resistant to conventional therapies than its differentiated counterpart. In order to understand glioma recurrence post therapy, we investigated the behavior of GSCs after primary chemotherapy. We first show that exposure of patient-derived as well as established glioma cell lines to therapeutic doses of temozolomide (TMZ), the most commonly used antiglioma chemotherapy, consistently increases the GSC pool over time both in vitro and in vivo . Secondly, lineage-tracing analysis of the expanded GSC pool suggests that such amplification is a result of a phenotypic shift in the non-GSC population to a GSC-like state in the presence of TMZ. The newly converted GSC population expresses markers associated with pluripotency and stemness, such as CD133, SOX2, Oct4, and Nestin. Furthermore, we show that intracranial implantation of the newly converted GSCs in nude mice results in a more efficient grafting and invasive phenotype. Taken together, these findings provide the first evidence that glioma cells exposed to chemotherapeutic agents are able to interconvert between non-GSCs and GSCs, thereby replenishing the original tumor population, leading to a more infiltrative phenotype and enhanced chemoresistance. This may represent a potential mechanism for therapeutic relapse.

Temozolomide and dacarbazine are untargeted anticancer prodrugs that have been widely employed in the treatment of melanoma and glioblastoma. These agents decompose into a short-lived monomethyl triazene intermediate, culminating in the release of a methyl diazonium cation that serves as the DNA-alkylating species responsible for tumour destruction. However, due to their high chemical lability, these agents have been associated with chemotherapy resistance, mutagenicity, tumour relapse, and significant off-target toxicity. One promising strategy towards the resolution of these limitations involves the design of arylmethyl triazene prodrugs, which enable targeted tumour-specific drug delivery. This review explores the various approaches used to selectively deliver alkyl aryl triazenes as alternatives to current therapies. It highlights early chemical strategies such as N-acylation and etherification of monomethyl triazenes, along with associated kinetic studies. The selective activation of novel triazenes in murine and human melanoma cells through a tyrosinase-responsive promoiety is discussed. Recent progress in nitroaromatic-based prodrugs designed to exploit the hypoxic microenvironment of glioblastoma is also examined. Additionally, we summarise the development of combi-triazenes and their underlying chemistries, which enable the simultaneous release of two active therapeutic agents.

Focused ultrasound (FUS) exposure with the presence of microbubbles has been shown to transiently open the blood-brain barrier (BBB), and thus has potential to enhance the delivery of various kinds of therapeutic agents into brain tumors. The purpose of this study was to assess the preclinical therapeutic efficacy of FUS-BBB opening for enhanced temozolomide (TMZ) delivery in glioma treatment. FUS exposure with microbubbles was delivered to open the BBB of nude mice that were either normal or implanted with U87 human glioma cells. Different TMZ dose regimens were tested, ranging from 2.5 to 25 mg/kg. Plasma and brain samples were obtained at different time-points ranging from 0.5 to 4 hours, and the TMZ concentration within samples was quantitated via a developed LC-MS/MS procedure. Tumor progression was followed with T2-MRI, and animal survival and brain tissue histology were conducted. Results demonstrated that FUS-BBB opening caused the local TMZ accumulation in the brain to increase from 6.98 to 19 ng/mg. TMZ degradation time in the tumor core was found to increase from 1.02 to 1.56 hours. Improved tumor progression and animal survival were found at different TMZ doses (up to 15% and 30%, respectively). In conclusion, this study provides preclinical evidence that FUS-BBB opening increases the local concentration of TMZ to improve the control of tumor progression and animal survival, suggesting the potential for clinical application to improve current brain tumor treatment.

High-grade gliomas, glioblastomas (GB), are refractory to conventional treatment combining surgery, chemotherapy, mainly temozolomide, and radiotherapy. This highlights an urgent need to develop novel therapies and increase the efficacy of radio/chemotherapy for these very aggressive and malignant brain tumors. Recently, tumor metabolism became an interesting potential therapeutic target in various cancers. Accordingly, combining drugs targeting cell metabolism with appropriate chemotherapeutic agents or radiotherapy has become attractive. In light of these perspectives, we were particularly interested in the anti-cancer properties of a biguanide molecule used for type 2 diabetes treatment, metformin. In our present work, we demonstrate that metformin decreases mitochondrial-dependent ATP production and oxygen consumption and increases lactate and glycolytic ATP production. We show that metformin induces decreased proliferation, cell cycle arrest, autophagy, apoptosis and cell death in vitro with a concomitant activation of AMPK, Redd1 and inhibition of the mTOR pathway. Cell sensitivity to metformin also depends on the genetic and mutational backgrounds of the different GB cells used in this study, particularly their PTEN status. Interestingly, knockdown of AMPK and Redd1 with siRNA partially, but incompletely, abrogates the induction of apoptosis by metformin suggesting both AMPK/Redd1-dependent and -independent effects. However, the primary determinant of the effect of metformin on cell growth is the genetic and mutational backgrounds of the glioma cells. We further demonstrate that metformin treatment in combination with temozolomide and/or irradiation induces a synergistic anti-tumoral response in glioma cell lines. Xenografts performed in nude mice demonstrate in vivo that metformin delays tumor growth. As current treatments for GB commonly fail to cure, the need for more effective therapeutic options is overwhelming. Based on these results, metformin could represent a potential enhancer of the cytotoxic effects of temozolomide and/or radiotherapy.