The Case for Neurosurgical Intervention in Cancer Neuroscience.

The emerging field of cancer neuroscience reshapes our understanding of the intricate relationship between the nervous system and cancer biology; this new paradigm is likely to fundamentally change and advance neuro-oncological care. The profound interplay between cancers and the nervous system is reciprocal: Cancer growth can be induced and regulated by the nervous system; conversely, tumors can themselves alter the nervous system. Such crosstalk between cancer cells and the nervous system is evident in both the peripheral and central nervous systems. Recent advances have uncovered numerous direct neuron-cancer interactions at glioma-neuronal synapses, paracrine mechanisms within the tumor microenvironment, and indirect neuroimmune interactions. Neurosurgeons have historically played a central role in neuro-oncological care, and as the field of cancer neuroscience is becoming increasingly established, the role of neurosurgical intervention is becoming clearer. Examples include peripheral denervation procedures, delineation of neuron-glioma networks, development of neuroprostheses, neuromodulatory procedures, and advanced local delivery systems. The present review seeks to highlight key cancer neuroscience mechanisms with neurosurgical implications and outline the future role of neurosurgical intervention in cancer neuroscience.

Recurrent Glioblastoma-Molecular Underpinnings and Evolving Treatment Paradigms.

Glioblastoma is the most common and lethal central nervous system malignancy with a median survival after progression of only 6-9 months. Major biochemical mechanisms implicated in glioblastoma recurrence include aberrant molecular pathways, a recurrence-inducing tumor microenvironment, and epigenetic modifications. Contemporary standard-of-care (surgery, radiation, chemotherapy, and tumor treating fields) helps to control the primary tumor but rarely prevents relapse. Cytoreductive treatment such as surgery has shown benefits in recurrent glioblastoma; however, its use remains controversial. Several innovative treatments are emerging for recurrent glioblastoma, including checkpoint inhibitors, chimeric antigen receptor T cell therapy, oncolytic virotherapy, nanoparticle delivery, laser interstitial thermal therapy, and photodynamic therapy. This review seeks to provide readers with an overview of (1) recent discoveries in the molecular basis of recurrence; (2) the role of surgery in treating recurrence; and (3) novel treatment paradigms emerging for recurrent glioblastoma.

Clinical trial links oncolytic immunoactivation to survival in glioblastoma.

Immunotherapy failures can result from the highly suppressive tumour microenvironment that characterizes aggressive forms of cancer such as recurrent glioblastoma (rGBM)1,2. Here we report the results of a first-in-human phase I trial in 41 patients with rGBM who were injected with CAN-3110-an oncolytic herpes virus (oHSV)3. In contrast to other clinical oHSVs, CAN-3110 retains the viral neurovirulence ICP34.5 gene transcribed by a nestin promoter; nestin is overexpressed in GBM and other invasive tumours, but not in the adult brain or healthy differentiated tissue4. These modifications confer CAN-3110 with preferential tumour replication. No dose-limiting toxicities were encountered. Positive HSV1 serology was significantly associated with both improved survival and clearance of CAN-3110 from injected tumours. Survival after treatment, particularly in individuals seropositive for HSV1, was significantly associated with (1) changes in tumour/PBMC T cell counts and clonal diversity, (2) peripheral expansion/contraction of specific T cell clonotypes; and (3) tumour transcriptomic signatures of immune activation. These results provide human validation that intralesional oHSV treatment enhances anticancer immune responses even in immunosuppressive tumour microenvironments, particularly in individuals with cognate serology to the injected virus. This provides a biological rationale for use of this oncolytic modality in cancers that are otherwise unresponsive to immunotherapy (ClinicalTrials.gov: NCT03152318 ).

Intratumoral drug-releasing microdevices allow in situ high-throughput pharmaco phenotyping in patients with gliomas.

The lack of reliable predictive biomarkers to guide effective therapy is a major obstacle to the advancement of therapy for high-grade gliomas, particularly glioblastoma (GBM), one of the few cancers whose prognosis has not improved over the past several decades. With this pilot clinical trial (number NCT04135807), we provide first-in-human evidence that drug-releasing intratumoral microdevices (IMDs) can be safely and effectively used to obtain patient-specific, high-throughput molecular and histopathological drug response profiling. These data can complement other strategies to inform the selection of drugs based on their observed antitumor effect in situ. IMDs are integrated into surgical practice during tumor resection and remain in situ only for the duration of the otherwise standard operation (2 to 3 hours). None of the six enrolled patients experienced adverse events related to the IMD, and the exposed tissue was usable for downstream analysis for 11 out of 12 retrieved specimens. Analysis of the specimens provided preliminary evidence of the robustness of the readout, compatibility with a wide array of techniques for molecular tissue interrogation, and promising similarities with the available observed clinical-radiological responses to temozolomide. From an investigational aspect, the amount of information obtained with IMDs allows characterization of tissue effects of any drugs of interest, within the physiological context of the intact tumor, and without affecting the standard surgical workflow.

The Translational and Regulatory Development of an Implantable Microdevice for Multiple Drug Sensitivity Measurements in Cancer Patients.

OBJECTIVE: The purpose of this article is to report the translational process of an implantable microdevice platform with an emphasis on the technical and engineering adaptations for patient use, regulatory advances, and successful integration into clinical workflow. METHODS: We developed design adaptations for implantation and retrieval, established ongoing monitoring and testing, and facilitated regulatory advances that enabled the administration and examination of a large set of cancer therapies simultaneously in individual patients. RESULTS: Six applications for oncology studies have successfully proceeded to patient trials, with future applications in progress. CONCLUSION: First-in-human translation required engineering design changes to enable implantation and retrieval that fit with existing clinical workflows, a regulatory strategy that enabled both delivery and response measurement of up to 20 agents in a single patient, and establishment of novel testing and quality control processes for a drug/device combination product without clear precedents. SIGNIFICANCE: This manuscript provides a real-world account and roadmap on how to advance from animal proof-of-concept into the clinic, confronting the question of how to use research to benefit patients.

Combined immunotherapy with controlled interleukin-12 gene therapy and immune checkpoint blockade in recurrent glioblastoma: An open-label, multi-institutional phase I trial.

BACKGROUND: Veledimex (VDX)-regulatable interleukin-12 (IL-12) gene therapy in recurrent glioblastoma (rGBM) was reported to show tumor infiltration of CD8+ T cells, encouraging survival, but also up-regulation of immune checkpoint signaling, providing the rationale for a combination trial with immune checkpoint inhibition. METHODS: An open-label, multi-institutional, dose-escalation phase I trial in rGBM subjects (NCT03636477) accrued 21 subjects in 3 dose-escalating cohorts: (1) neoadjuvant then ongoing nivolumab (1mg/kg) and VDX (10 mg) (n = 3); (2) neoadjuvant then ongoing nivolumab (3 mg/kg) and VDX (10 mg) (n = 3); and (3) neoadjuvant then ongoing nivolumab (3 mg/kg) and VDX (20 mg) (n = 15). Nivolumab was administered 7 (±3) days before resection of the rGBM followed by peritumoral injection of IL-12 gene therapy. VDX was administered 3 hours before and then for 14 days after surgery. Nivolumab was administered every two weeks after surgery. RESULTS: Toxicities of the combination were comparable to IL-12 gene monotherapy and were predictable, dose-related, and reversible upon withholding doses of VDX and/or nivolumab. VDX plasma pharmacokinetics demonstrate a dose-response relationship with effective brain tumor tissue VDX penetration and production of IL-12. IL-12 levels in serum peaked in all subjects at about Day 3 after surgery. Tumor IFNγ increased in post-treatment biopsies. Median overall survival (mOS) for VDX 10 mg with nivolumab was 16.9 months and for all subjects was 9.8 months. CONCLUSION: The safety of this combination immunotherapy was established and has led to an ongoing phase II clinical trial of immune checkpoint blockade with controlled IL-12 gene therapy (NCT04006119).

The Evolving Role of Neurosurgical Intervention for Central Nervous System Tumors.

Since its inception, greater than a century ago, neurosurgery has represented the fundamental trait-d'union between clinical management, scientific investigation, and therapeutic advancements in the field of brain tumors. During the years, oncological neurosurgery has evolved as a self-standing subspecialty, due to technical progress, equipment improvement, evolution of therapeutic paradigms, and the progressively crucial role that it plays in the execution of complex therapeutic strategies and modern clinical trials.

Ruptured Suprasellar Dermoid Cyst Treated With Lumbar Drain to Prevent Postoperative Hydrocephalus: Case Report and Focused Review of Literature.

Background: Ruptured intracranial dermoid cysts are extremely rare. Standard treatment consists of endonasal decompression or craniotomy with evacuation and copious irrigation of subarachnoid spaces to remove any disseminated cystic contents. Disseminated fat particles in the subarachnoid space may be the cause of further sequalae, including the subsequent development of chemical meningitis and hydrocephalus. Here, we present a case of ruptured suprasellar dermoid cyst treated with craniotomy for emergent optic nerve decompression, followed by postoperative hydrocephalus successfully treated with lumbar drain. Case description: We describe a 30-year-old man with a history of migraines who presented with acute onset of headache, photophobia, nausea, vomiting, and vision loss in the left eye. Head CT and brain MRI demonstrated a ruptured suprasellar dermoid cyst with associated mass effect on the optic nerves and frontal lobes as well as fat attenuation material within the subarachnoid spaces. The patient underwent left frontotemporal craniotomy for cyst resection and developed non-obstructive hydrocephalus on postoperative day 1, refractory to external ventricular drainage. Placement of a lumbar drain cleared the subarachnoid space of debris derived from the ruptured dermoid cyst, and the hydrocephalus resolved. The patient did not require permanent CSF diversion. Conclusions: Intracranial dermoid cysts are uncommon, and rupture is a rare event. Standard surgical treatment with craniotomy for evacuation may leave disseminated dermoid contents and fat particles throughout the subarachnoid spaces. We highlight a case of ruptured suprasellar dermoid cyst with postoperative communicating hydrocephalus treated with lumbar drain when external ventricular drain (EVD) was ineffective. Review of the current literature reveals inconsistent findings on the effects of remaining fat particles. In cases with clinical evidence of increased intracranial pressure due to non-obstructive hydrocephalus attributable to chemical meningitis, temporary lumbar drainage is an option to be considered before committing the patient to permanent shunting.

Engineering, delivery, and biological validation of artificial microRNA clusters for gene therapy applications.

The cellular machinery regulating microRNA biogenesis and maturation relies on a small number of simple steps and minimal biological requirements and is broadly conserved in all eukaryotic cells. The same holds true in disease. This allows for a substantial degree of freedom in the engineering of transgenes capable of simultaneously expressing multiple microRNAs of choice, allowing a more comprehensive modulation of microRNA landscapes, the study of their functional interaction, and the possibility of using such synergism for gene therapy applications. We have previously engineered a transgenic cluster of functionally associated microRNAs to express a module of suppressed microRNAs in brain cancer for therapeutic purposes. Here, we provide a detailed protocol for the design, cloning, delivery, and utilization of such artificial microRNA clusters for gene therapy purposes. In comparison with other protocols, our strategy effectively decreases the requirements for molecular cloning, because the nucleic acid sequence encoding the combination of the desired microRNAs is designed and validated in silico and then directly synthesized as DNA that is ready for subcloning into appropriate delivery vectors, for both in vitro and in vivo use. Sequence design and engineering require 4-5 h. Synthesis of the resulting DNA sequence requires 4-6 h. This protocol is quick and flexible and does not require special laboratory equipment or techniques, or multiple cloning steps. It can be easily executed by any graduate student or technician with basic molecular biology knowledge.

Characterization of Functionally Associated miRNAs in Glioblastoma and their Engineering into Artificial Clusters for Gene Therapy.

The biological relevance of microRNAs (miRNAs) in health and disease significantly relies on specific combinations of many simultaneously deregulated miRNAs rather than the action of a single miRNA. The characterization of these specific miRNAs modules is a fundamental step in maximizing their use in therapy. This is extremely relevant because their combinatorial attributes can be practically exploited. Described here is a method to define a specific miRNA signature relevant to the control of oncogenic chromatin repressors in glioblastoma. The approach first defines a general group of miRNAs that are deregulated in tumors in comparison to normal tissue. The analysis is further refined by differential culture conditions, underscoring a subgroup of miRNAs that are co-expressed simultaneously during specific cellular states. Finally, the miRNAs that satisfy these filters are combined into an artificial polycistronic transgenes, which is based on a scaffold of naturally existing miRNA clusters genes, then used for overexpression of these miRNA modules into receiving cells.

MicroRNAs in Brain Cancer: Look at the Forest, Not at the Tree.

Much is known about microRNA biology and their involvement in essentially any biological processes in eukaryotic cells, including cancer. Now, to take advantage of them in clinics, a change in perspective is needed and a reappraisal of their features is warranted to re-ignite interest and translational hype. As we recently reported, their strength is in numbers, size and simplicity.

The functional synergism of microRNA clustering provides therapeutically relevant epigenetic interference in glioblastoma.

MicroRNA deregulation is a consistent feature of glioblastoma, yet the biological effect of each single gene is generally modest, and therapeutically negligible. Here we describe a module of microRNAs, constituted by miR-124, miR-128 and miR-137, which are co-expressed during neuronal differentiation and simultaneously lost in gliomagenesis. Each one of these miRs targets several transcriptional regulators, including the oncogenic chromatin repressors EZH2, BMI1 and LSD1, which are functionally interdependent and involved in glioblastoma recurrence after therapeutic chemoradiation. Synchronizing the expression of these three microRNAs in a gene therapy approach displays significant anticancer synergism, abrogates this epigenetic-mediated, multi-protein tumor survival mechanism and results in a 5-fold increase in survival when combined with chemotherapy in murine glioblastoma models. These transgenic microRNA clusters display intercellular propagation in vivo, via extracellular vesicles, extending their biological effect throughout the whole tumor. Our results support the rationale and feasibility of combinatorial microRNA strategies for anticancer therapies.

Viral and other therapies for recurrent glioblastoma: is a 24-month durable response unusual?

A phase I trial of an engineered poliovirus for the treatment of recurrent glioblastoma (GBM) has attracted attention due to 8 survivors reaching the 24-month and 5 reaching the 36-month survival landmarks.1 Genetically engineered viruses (oncolytic viruses) have been in trials for GBM for almost two decades.2 These replication-competent (tumor-selective, oncolytic, replication-conditional) viruses or replication-defective viral vectors (gene therapy) deliver cytotoxic payloads to tumors, leading to immunogenic death and intratumoral inflammatory responses. This transforms the tumor microenvironment from immunologically naïve ("cold") to inflamed ("hot"), increasing immune cell recognition of tumor antigens and the durable responses observed in virotherapy.3,4 Several current and past virotherapy trials have reported a "tail" of apparent responders at the 24-month landmark. Other modalities have also reported a "tail" of seemingly long-term survivors. These trials seem to show that these responder "tails" characterize a defined subset of GBM patients.

Extracellular vesicles modulate the glioblastoma microenvironment via a tumor suppression signaling network directed by miR-1.

Extracellular vesicles have emerged as important mediators of intercellular communication in cancer, including by conveying tumor-promoting microRNAs between cells, but their regulation is poorly understood. In this study, we report the findings of a comparative microRNA profiling and functional analysis in human glioblastoma that identifies miR-1 as an orchestrator of extracellular vesicle function and glioblastoma growth and invasion. Ectopic expression of miR-1 in glioblastoma cells blocked in vivo growth, neovascularization, and invasiveness. These effects were associated with a role for miR-1 in intercellular communication in the microenvironment mediated by extracellular vesicles released by cancer stem-like glioblastoma cells. An extracellular vesicle-dependent phenotype defined by glioblastoma invasion, neurosphere growth, and endothelial tube formation was mitigated by loading miR-1 into glioblastoma-derived extracellular vesicles. Protein cargo in extracellular vesicles was characterized to learn how miR-1 directed extracellular vesicle function. The mRNA encoding Annexin A2 (ANXA2), one of the most abundant proteins in glioblastoma-derived extracellular vesicles, was found to be a direct target of miR-1 control. In addition, extracellular vesicle-derived miR-1 along with other ANXA2 extracellular vesicle networking partners targeted multiple pro-oncogenic signals in cells within the glioblastoma microenvironment. Together, our results showed how extracellular vesicle signaling promotes the malignant character of glioblastoma and how ectopic expression of miR-1 can mitigate this character, with possible implications for how to develop a unique miRNA-based therapy for glioblastoma management.

MicroRNA-128 coordinately targets Polycomb Repressor Complexes in glioma stem cells.

BACKGROUND: The Polycomb Repressor Complex (PRC) is an epigenetic regulator of transcription whose action is mediated by 2 protein complexes, PRC1 and PRC2. PRC is oncogenic in glioblastoma, where it is involved in cancer stem cell maintenance and radioresistance. METHODS: We used a set of glioblastoma patient samples, glioma stem cells, and neural stem cells from a mouse model of glioblastoma. We characterized gene/protein expression and cellular phenotypes by quantitative PCR/Western blotting and clonogenic, cell-cycle, and DNA damage assays. We performed overexpression/knockdown studies by lentiviral infection and microRNA/small interfering RNA oligonucleotide transfection. RESULTS: We show that microRNA-128 (miR-128) directly targets mRNA of SUZ12, a key component of PRC2, in addition to BMI1, a component of PRC1 that we previously showed as a target as well. This blocks the partially redundant functions of PRC1/PRC2, thereby significantly reducing PRC activity and its associated histone modifications. MiR-128 and SUZ12/BMI1 show opposite expression in human glioblastomas versus normal brain and in glioma stemlike versus neural stem cells. Furthermore, miR-128 renders glioma stemlike cells less radioresistant by preventing the radiation-induced expression of both PRC components. Finally, miR-128 expression is significantly reduced in neural stem cells from the brain of young, presymptomatic mice in our mouse model of glioblastoma. This suggests that loss of miR-128 expression in brain is an early event in gliomagenesis. Moreover, knockdown of miR-128 expression in nonmalignant mouse and human neural stem cells led to elevated expression of PRC components and increased clonogenicity. CONCLUSIONS: MiR-128 is an important suppressor of PRC activity, and its absence is an early event in gliomagenesis.

Assessment of glycemic control among diabetic residents in nursing homes.

We assessed hemoglobin A1c (HbA1c) among 88 diabetic residents in three Italian nursing homes, and compared figures with current guidelines and reports in the literature. Mean HbA1c was 6.5%; this paper from Southern Europe confirms recent findings in nursing homes on HbA1c values well below recommended targets.