Preclinical impact of bevacizumab on brain and tumor distribution of irinotecan and temozolomide

Granulocyte-macrophage colony-stimulating factor enhances effect of temozolomide on high-grade glioma cells

In the present study, to delve into the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with temozolomide (TMZ) on high-grade glioma cells and related mechanism, six cases of high-grade glioma cells from patient's tumor tissues were cultured. 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay was performed to detect cell proliferation and toxicity. Flow cytometry was performed to ascertain cell cycle and apoptosis rate. To detect the expressions of O6-methylguanine-DNA methyltransferase (MGMT) methylation status and MGMT protein, respectively, specific PCR and immunofluorescence were performed. According to the results of MTT assay, compared with the results of control group, GM-CSF group exhibited enhanced cell viability in varying degrees. In three cases of cells (MGMT gene methylation), the combination group [(67.67 ± 1.16), (68.13 ± 1.06), (68.42 ± 1.73)] had noticeably lower cell viability than the corresponding TMZ group [(90.00 ± 1.73), (82.33 ± 1.53), (82.67 ± 2.11)] (P < 0.01). Nevertheless, the two groups showed no significant difference in another three cases (MGMT gene unmethylated) (P > 0.05). In combination group, the apoptosis rate of the MGMT methylation cells was higher than that in the corresponding TMZ group (P < 0.01), which is consistent with MTT assay results. In all six cases of primary glioma cells, the fraction of cells in G1 phase of GM-CSF-treated group was noticeably down-regulated and was up-regulated in S phase (P < 0.01). GM-CSF could induce high-grade glioma cells to rapidly enter the cell cycle, thereby enhancing the lethal effect of TMZ on glioma cells with MGMT gene promoter methylation. However, this effect is not ideal on glioma cells with MGMT unmethylation.

Blood-brain barrier disruption in humans using an implantable ultrasound device: quantification with MR images and correlation with local acoustic pressure

OBJECTIVE

One of the goals in this study was to set up a semiautomatic method to estimate blood-brain barrier disruption obtained in patients with glioblastoma by using an implantable, unfocused, ultrasound device. Another goal was to correlate the probability of significant ultrasound-induced signal enhancement (SUISE) with local acoustic pressure in the brain.

METHODS

Gd-enhanced MR images acquired before and after ultrasound treatments were analyzed prospectively. The image sets were segmented, normalized, and coregistered to evaluate contrast enhancement. The volume of SUISE was calculated with voxels labeled as gray or white matter, in a cylindrical region of interest, and with enhancement above a given threshold. To validate the method, the resulting volumes of SUISE were compared to qualitative grades previously assigned by 3 clinicians for 40 ultrasound treatments in 15 patients. A parametric study was performed to optimize the algorithm prediction of the qualitative grades. The 3D acoustic field in the brain was estimated from measurements in water combined with simulations accounting for ultrasound attenuation in brain and overlaid on each MR image to correlate local acoustic pressure with the probability of SUISE (defined as enhancement > 10%).

RESULTS

The algorithm predicted grade 2 or 3 and grade 3 openings with areas under the receiver operating characteristic curve of 0.831 and 0.995, respectively. The probability of SUISE was correlated with local acoustic pressure (R2 = 0.98) and was 3.33 times higher for gray matter than for white matter.

CONCLUSIONS

An algorithm for evaluating blood-brain barrier disruption was validated and can be used for future clinical trials to further understand and quantify this technique in humans.Clinical trial registration no.: NCT02253212 (clinicaltrials.gov).

Combining therapy with recombinant human endostatin and cytotoxic agents for recurrent disseminated glioblastoma: a retrospective study

BACKGROUND

The optimal chemotherapeutics of recurrent disseminated glioblastoma has yet to be determined. We analyzed the efficacy and safety of recombinant human endostatin (rh-ES) combined with temozolomide and irinotecan in patients with recurrent disseminated glioblastoma.

METHODS

We retrospectively reviewed 30 adult patients with recurrent disseminated glioblastoma treated with this combination chemotherapy at Department of Neuro-Oncology, Sanbo Brain Hospital, Capital Medical University of China from November 2009 to August 2018. Temozolomide was given orally at 200 mg/m² daily for 5 days and rh-ES was administrated 15 mg/d daily for 14 days of each 28-day treatment cycle. Irinotecan was given intravenously every 2 weeks on a 28-day cycle at 340 mg/m² or 125 mg/m² depending on antiepileptic drugs. Primary endpoint was progression-free survival (PFS) at 6 months (6 m-PFS).

RESULTS

The 6 m-PFS was 23.3%. The median PFS was 3.2 months. The overall survival rate (OS) at 12 months was 28.6%. The median OS was 6.9 months. Six out of 30 (20%) patients demonstrated partial radiographic response and 11 (36.7%) remained stable. The PFS of the 6 patients who got partial response was 5.8, 6.3, 6.9, 13.6, 15.8 and 16.6 months, respectively, and the median time interval of first response was 4 (range, 2.0-6.6) months. The most common adverse events were hematologic toxicities and gastrointestinal effects. The Grade ≥ 3 adverse event was hematologic toxicities. The adverse events were manageable.

CONCLUSIONS

Rh-ES, in combination with cytotoxic drugs, was an alternative effective regimen with manageable toxicities in treatment of recurrent disseminated glioblastoma.

Molecular and Clinical Insights into the Invasive Capacity of Glioblastoma Cells

The invasive capacity of GBM is one of the key tumoral features associated with treatment resistance, recurrence, and poor overall survival. The molecular machinery underlying GBM invasiveness comprises an intricate network of signaling pathways and interactions with the extracellular matrix and host cells. Among them, PI3k/Akt, Wnt, Hedgehog, and NFkB play a crucial role in the cellular processes related to invasion. A better understanding of these pathways could potentially help in developing new therapeutic approaches with better outcomes. Nevertheless, despite significant advances made over the last decade on these molecular and cellular mechanisms, they have not been translated into the clinical practice. Moreover, targeting the infiltrative tumor and its significance regarding outcome is still a major clinical challenge. For instance, the pre- and intraoperative methods used to identify the infiltrative tumor are limited when trying to accurately define the tumor boundaries and the burden of tumor cells in the infiltrated parenchyma. Besides, the impact of treating the infiltrative tumor remains unclear. Here we aim to highlight the molecular and clinical hallmarks of invasion in GBM.

Novel Insights into the Effect of Hyperforin and Photodynamic Therapy with Hypericin on Chosen Angiogenic Factors in Colorectal Micro-Tumors Created on Chorioallantoic Membrane

Photodynamic therapy with hypericin (HY-PDT) and hyperforin (HP) could be treatment modalities for colorectal cancer (CRC), but evidence of their effect on angiogenic factors in CRC is missing. Convenient experimental model utilization is essential for angiogenesis research. Therefore, not only 2D cell models, but also 3D cell models and micro-tumors were used and compared. The micro-tumor extent and interconnection with the chorioallantoic membrane (CAM) was determined by histological analyses. The presence of proliferating cells and HY penetration into the tumor mass were detected by fluorescence microscopy. The metabolic activity status was assessed by an colorimetric assay for assessing cell metabolic activity (MTT assay) and HY accumulation was determined by flow cytometry. Pro-angiogenic factor expression was determined by Western blot and quantitative real-time polymerase chain reaction (RT-qPCR). We confirmed the cytotoxic effect of HY-PDT and HP and showed that their effect is influenced by structural characteristics of the experimental model. We have pioneered a method for analyzing the effect of HP and cellular targeted HY-PDT on pro-angiogenic factor expression in CRC micro-tumors. Despite the inhibitory effect of HY-PDT and HP on CRC, the increased expression of some pro-angiogenic factors was observed. We also showed that CRC experimental micro-tumors created on quail CAM could be utilized for analyses of gene and protein expression.

Is the blood-brain barrier really disrupted in all glioblastomas? A critical assessment of existing clinical data

The blood-brain barrier (BBB) excludes the vast majority of cancer therapeutics from normal brain. However, the importance of the BBB in limiting drug delivery and efficacy is controversial in high-grade brain tumors, such as glioblastoma (GBM). The accumulation of normally brain impenetrant radiographic contrast material in essentially all GBM has popularized a belief that the BBB is uniformly disrupted in all GBM patients so that consideration of drug distribution across the BBB is not relevant in designing therapies for GBM. However, contrary to this view, overwhelming clinical evidence demonstrates that there is also a clinically significant tumor burden with an intact BBB in all GBM, and there is little doubt that drugs with poor BBB permeability do not provide therapeutically effective drug exposures to this fraction of tumor cells. This review provides an overview of the clinical literature to support a central hypothesis: that all GBM patients have tumor regions with an intact BBB, and cure for GBM will only be possible if these regions of tumor are adequately treated.

Antiangiogenic therapy: Markers of response, "normalization" and resistance

Currently in cancer treatment, one premise is to use antiangiogenic therapies in association with chemotherapy or radiotherapy to augment their efficacy by benefiting from the vascular "normalization" induced by antiangiogenic therapy. This concept defines the time during which the tumor blood vessels adopt normal-like morphology and functionality, i.e. the blood vessels become more mature, the perfusion augments and hypoxia decreases. To date, there is such a diversity of treatment protocols where the type of antiangiogenic to adopt, its dose and duration of administration are different, that knowing when and how to treat is problematic. In this review, we analyzed thoroughly preclinical and clinical studies that use antiangiogenic treatments to benefit from the "normalization" and showed that the effects depend on the type of antiangiogenic administrated (anti-VEGF, anti-VEGFR, Multi-Kinase Inhibitor) and on the duration of treatment. Finally, biomarkers of "normalization" and resistance that could be used in the clinic are presented.

Limited Tumor Tissue Drug Penetration Contributes to Primary Resistance against Angiogenesis Inhibitors

Resistance mechanisms against antiangiogenic drugs are unclear. Here, we correlated the antitumor and antivascular properties of five different antiangiogenic receptor tyrosine kinase inhibitors (RTKIs) (motesanib, pazopanib, sorafenib, sunitinib, vatalanib) with their intratumoral distribution data obtained by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). In the first mouse model, only sunitinib exhibited broad-spectrum antivascular and antitumor activities by simultaneously suppressing vascular endothelial growth factor receptor-2 (VEGFR2) and desmin expression, and by increasing intratumoral hypoxia and inhibiting both tumor growth and vascularisation significantly. Importantly, the highest and most homogeneous intratumoral drug concentrations have been found in sunitinib-treated animals. In another animal model, where - in contrast to the first model - vatalanib was detectable at homogeneously high intratumoral concentrations, the drug significantly reduced tumor growth and angiogenesis. In conclusion, the tumor tissue penetration and thus the antiangiogenic and antitumor potential of antiangiogenic RTKIs vary among the tumor models and our study demonstrates the potential of MALDI-MSI to predict the efficacy of unlabelled small molecule antiangiogenic drugs in malignant tissue. Our approach is thus a major technical and preclinical advance demonstrating that primary resistance to angiogenesis inhibitors involves limited tumor tissue drug penetration. We also conclude that MALDI-MSI may significantly contribute to the improvement of antivascular cancer therapies.

A new algorithm for a better characterization and timing of the anti-VEGF vascular effect named "normalization"

Antiangiogenics are widely used in cancer treatment in combination with chemotherapy and radiotherapy for their vascular effects. Antiangiogenics are supposed to induce morphological and functional changes in the chaotic tumor vasculature that would help enhance the therapeutic efficacy of chemotherapy and radiotherapy through the amelioration of the drug delivery or the oxygenation in the tumor, respectively. However, finding the best treatment sequence is not an easy task to achieve and no consensus has yet been established because of the lack of knowledge regarding when and for how long the vascular network is ameliorated. The aim of this work was to develop a dedicated image processing algorithm able to analyze the vascular structures on optical microscopy images of the vascular network and to follow its fine modifications in vivo, over time. We applied this algorithm to follow the evolution of the vascular parameters (vascularized tissue surface, branches, sprouts and length), in response or not to anti-VEGF therapy (10 mg/kg/day) and determine precisely whether there is really a vascular "normalization" with anti-VEGF therapy in comparison with the parameters extracted from healthy vascular networks. We found that for this determination, the choice of region of interest to analyze is critical as it is important to compare only microcirculation areas and avoid areas with arteriole-venule-capillary hierarchy. The algorithm analysis allowed us to define a vascular "normalization" in treated tumors, between 8 and 12 days of bevacizumab treatment that was confirmed by standard immunohistochemical analysis, microvascular permeability assessment and immunohistological blood perfusion assessment.

Combination therapy in cancer: effects of angiogenesis inhibitors on drug pharmacokinetics and pharmacodynamics

Validated preclinical studies have provided evidence that anti-vascular endothelial growth factor (VEGF) compounds enhance the activity of subsequent antitumor therapy, but the mechanism of this potentiation is far from clear. The most widespread explanation is enhanced delivery of therapeutics due to vascular remodeling, lower interstitial pressure, and increased blood flow. While the antiangiogenic effects on vascular morphology have been fairly consistent in both preclinical and clinical settings, the improvement of tumor vessel function is debated. This review focuses on the effect of anti-VEGF therapy on tumor microenvironment morphology and functions, and its therapeutic benefits when combined with other therapies. The uptake and spatial distribution of chemotherapeutic agents into the tumor after anti-VEGF are examined.