Residual Glioma Cells Research Articles

In Situ Attached Photothermal Immunomodulation-Enhanced Nanozyme for the Inhibition of Postoperative Malignant Glioma Recurrence.

Glioblastoma (GBM) is one of the most challenging malignant brain tumors to treat. Herein, we describe a nanoenzyme hemostatic matrix strategy with the tumor cavity in situ application that simultaneously serves as photothermal agent and induces immunogenic cell death after GBM surgical resection to enhance the antitumor immunity and delay tumor recurrence. The hemostatic matrix system (Surgiflo@PCN) contains Surgiflo, a multispace structure that can be used to penetrate different shapes of tumor cavities to prevent postoperative tumor cavity hemorrhage. As well, porous palladium-copper nanoclusters (PCNs) have adjustable enzyme-like activities (oxidase, peroxidase, and catalase) responsible for formation of reactive oxygen species (ROS) under near-infrared (808 nm) laser irradiation. When the Surgiflo@PCN entered the resected tumor cavity, the first action was the direct killing of glioma cells via ROS and photothermal therapy (PTT). The second action was the induction of immunogenic cell death by PCN-enhanced oxidative stress and PTT, which reversed the immunosuppressive tumor microenvironment and enhanced the antitumor immune response. This eradicated residual glioma cells and prevented recurrence. The collective findings demonstrate that Surgiflo@PCN kills glioma cells directly through ROS and PTT and enhances antiglioma immunity and kills glioma cells indirectly. The "one-stone, two-birds" strategy could become an effective photothermal immunotherapy in GBM patients.

Reduced malignant glioblastoma recurrence post-resection through the anti-CD47 antibody and Temozolomide co-embedded in-situ hydrogel system.

Infiltrative glioma growth makes surgical excision incomplete, and the residual tumor cells proliferate rapidly. Residual glioma cells evade phagocytosis by macrophages through upregulating anti-phagocytosis molecule CD47, which binds to the signal regulatory protein alpha (SIRPα) of macrophages. Specifically, blocking the CD47-SIRPα pathway is a potential strategy for post-resection glioma treatment. In addition, the anti-CD47 antibody (α-CD47) in combination with temozolomide (TMZ) caused an enhanced pro-phagocytic effect due to the TMZ not only destroying DNA but also inducing endoplasmic reticulum stress response of glioma cells. However, the obstruction of the blood-brain barrier makes systemic combination therapy not ideal for post-resection glioma treatment. Herein, we designed a temperature-sensitive hydrogel system based on a moldable thermosensitive hydroxypropyl chitin (HPCH) copolymer to encapsulate both α-CD47 and TMZ as α-CD47&TMZ@Gel for in situ postoperative cavity administration. Through the in vitro and in vivo evaluations, α-CD47&TMZ@Gel significantly inhibited glioma recurrence post-resection through enhancement of pro-phagocytosis of macrophages, recruitment, and activation of CD8+ T cells and NK cells.

Preoperative administration of a biomimetic platelet nanodrug enhances postoperative drug delivery by bypassing thrombus

The postoperative thrombus attached to the damaged blood vessels severely obstructs drugs from crossing the damaged blood–brain barrier (BBB) and targeting residual glioma cells around surgical margins, leading to glioblastoma (GBM) recurrence. A thrombus-bypassing, BBB-crossing, and surgical margin-targeted nanodrug is needed to address this phenomenon. Encouraged by the intrinsic damaged vascular endothelium chemotaxis of platelets, a platelet membrane-coated nanodrug (PM-HDOX) delivering doxorubicin (DOX) for postoperative GBM treatment is proposed and systematically investigated. Because surgery damages the vascular endothelium on the BBB around the surgical margin, the platelet membrane coating endows PM-HDOX with its inherent capacity to cross the broken BBB and target the surgical margin. Moreover, preoperative administration combined with fast-targeted PM-HDOX can realize the potential of bypassing thrombus. In GBM resection models, PM-HDOX with preoperative administration demonstrated significantly enhanced BBB-crossing and surgical margin-targeted efficacy. In particular, the PM-HDOX intensities around the surgical margins of the preoperative administration group were more than twice that of the postoperative administration group due to bypassing the thrombus formed in the broken BBB. In the antitumor experiment, the preoperative administration of PM-HDOX significantly inhibited the growth of postoperative residual tumors and prolonged the median survival time of mice. In conclusion, preoperative administration of a biomimetic platelet nanodrug can be an efficient and promising drug delivery strategy for residual GBM after surgery.

Harnessing Reconstructed Macrophage Modulation of Infiltration-Excluded Immune Microenvironments To Delineate Glioma Infiltrative Region.

High invasiveness of glioma produces residual glioma cells in the brain parenchyma after surgery and ultimately causes recurrence. Precise delineation of glioma infiltrative region is critical for an accurate complete resection, which is challenging. The glioma-infiltrating area constitutes infiltration-excluded immune microenvironments (I-E TIMEs), which recruits endogenous or adoptive macrophages to the invasive edge of glioma. Thus, combined with immune cell tracing technology, we provided a novel strategy for the preoperative precise definition of the glioma infiltration boundary, even satellite-like infiltration stoves. Herein, the biomimetic probe was constructed by internalizing fluorophore labeled PEGylated KMnF3 nanoparticles into bone-marrow-derived macrophages using magnetic resonance imaging (MRI)/fluorescence imaging (FI). The biomimetic probe was able to cross the blood-brain barrier and home to the orthotopic glioma infiltrates including satellite stove under MRI and FI tracing, which was validated using hematoxylin and eosin staining, indicating its excellent performance in distinguishing the margins between the glioma cell and normal tissues. This study guides the precise definition of glioma infiltration boundaries at the cellular level, including the observation of any residual glioma cells after surgery. Thus, it has the potential to guide surgery to maximize resection and predict recurrence in the clinic.

Multifunctional Hybrid Hydrogel System Enhanced the Therapeutic Efficacy of Treatments for Postoperative Glioma.

Glioma is the most lethal brain tumor with a poor prognosis, and a combination of multiple therapeutic strategies is critical for postoperative glioma treatment. Herein, a multifunctional hybrid hydrogel system (designated as CP&CL@RNPPTX-Gel) was developed for local treatment of postoperative glioma. The system was composed of self-illuminating chlorin e6 (Ce6) conjugated with luminol molecule (CL)-loaded glioma-targeting paclitaxel prodrug nanoparticles and copper peroxide nanodots (CP NDs) coembedded into a three-dimensional thermosensitive hydroxypropyl chitin hydrogel frame. After injection of CP&CL@RNPPTX-Gel into the cavity of postoperative glioma, the solution could be cross-linked into the gel as a drug reservoir under body temperature stimulation. Then, the sustained-released CP NDs decomposed into Cu2+ and H2O2 in the acidic microenvironment of the glioma cells to exert chemodynamic therapy (CDT). Meanwhile, Cu2+ could catalyze the self-luminescence of CL to induce photodynamic therapy (PDT) without external excitation light. Moreover, paclitaxel prodrug nanoparticles degraded into paclitaxel to restrain residual glioma cells in response to intracellular reduced glutathione (GSH). The in vitro and in vivo results showed that CP&CL@RNPPTX-Gel had great potential as a multifunctional hybrid hydrogel system with remarkable therapeutic effects for postoperative glioma treatment via a combination of chemotherapy, CDT, and PDT.

Whole exome sequencing reveals the genetic heterogeneity and evolutionary history of primary gliomas and matched recurrences

Diffuse glioma is a highly heterogeneous central nervous system tumor that is refractory to conventional therapy. Residual glioma cells escape from surgery and chemoradiotherapy, leading to lethal recurrence. Understanding the molecular mechanism of this recurrence process is critical to the development of successful therapies. Here, we analyzed whole-exome sequencing (WES) data of 97 paired primary and recurrent samples from 46 patients with glioma via a uniform pipeline. Clonality and phylogenetic analyses revealed that branching evolution was widespread in the recurrent process of gliomas. Recurrent tumors continued to evolve independently with chemoradiotherapy and harbored multiple recurrence-selected genetic alterations, such as amplification of PPFIBP1, PDE4DIP, and KRAS, deletion of TNFRSF14, DCC, CDKN2A, and MSH6, and mutations in ATRX, ARID1A, KEL, TP53, MSH6, and KMT2B. Meanwhile, truncal variants within partial driver genes were identified among primary and recurrent gliomas, suggesting that they might be ideal therapeutic targets. Intriguingly, the immunogenicity of recurrent gliomas did not increase significantly compared to the primary tumors. Genomic analysis of recurrent gliomas provided an opportunity to identify potentially clinically informative alterations not detected in clinically sampled primary tumors.

Hypoxia-Responsive Lipid-Polymer Nanoparticle-Combined Imaging-Guided Surgery and Multitherapy Strategies for Glioma.

Glioma is the most prevalent type of malignant brain tumor and is usually very aggressive. Because of the high invasiveness and aggressive proliferative growth of glioma, it is difficult to resect completely or cure with surgery. Residual glioma cells are a primary cause of postoperative recurrence. Herein, we describe a hypoxia-responsive lipid polymer nanoparticle (LN) for fluorescence-guided surgery, chemotherapy, photodynamic therapy (PDT), and photothermal therapy (PTT) combination multitherapy strategies targeting glioma. The hypoxia-responsive LN [LN (DOX + ICG)] contains a hypoxia-responsive component poly(nitroimidazole)25 [P-(Nis)25], the glioma-targeting peptide angiopep-2 (A2), indocyanine green (ICG), and doxorubicin (DOX). LN (DOX + ICG) comprises four distinct functional components: (1) A2: A2 modified nanoparticles effectively target gliomas, enhancing drug concentration in gliomas; (2) P-(Nis)25: (i) the hydrophobic component of LN (DOX + ICG) with hypoxia responsive ability to encapsulate DOX and ICG; (ii) allows rapid release of DOX from LN (DOX + ICG) after 808 nm laser irradiation; (3) ICG: (i) ICG allows imaging-guided surgery, combining PDT and PTT therapies; (ii) upon irradiation with an 808 nm laser, ICG creates a hypoxic environment; (4) DOX inhibits glioma growth. This work demonstrates that LN (DOX + ICG) might provide a novel clinical approach to preventing post-surgical recurrence of glioma.

Radiation Effects on Brain Extracellular Matrix.

Radiotherapy is an important therapeutic approach to treating malignant tumors of different localization, including brain cancer. Glioblastoma multiforme (GBM) represents the most aggressive brain tumor, which develops relapsed disease during the 1st year after the surgical removal of the primary node, in spite of active adjuvant radiochemotherapy. More and more evidence suggests that the treatment's success might be determined by the balance of expected antitumor effects of the treatment and its non-targeted side effects on the surrounding brain tissue. Radiation-induced damage of the GBM microenvironment might create tumor-susceptible niche facilitating proliferation and invasion of the residual glioma cells and the disease relapse. Understanding of molecular mechanisms of radiation-induced changes in brain ECM might help to reconsider and improve conventional anti-glioblastoma radiotherapy, taking into account the balance between its antitumor and ECM-destructing activities. Although little is currently known about the radiation-induced changes in brain ECM, this review summarizes current knowledge about irradiation effects onto the main components of brain ECM such as proteoglycans, glycosaminoglycans, glycoproteins, and the enzymes responsible for their modification and degradation.

SURG-20. IDENTIFICATION OF INFILTRATIVE CANCER CELLS AT THE GLIOMA RESECTION CAVITY MARGIN USING STIMULATED RAMAN SCATTERING MICROSCOPY

Abstract INTRODUCTION Microscopic residual disease at the tumor margin is the primary barrier to complete resection which impacts outcome. Stimulated Raman scattering microscopy (SRM) has proven effective to classify CNS tumor tissue and detect tumor cells within grossly normal post mortem glioma specimens. In this study, we use SRM for detection of residual glioma cells within the resection cavity margins. METHODS Patients with gliomas undergoing surgical resection were included. Margin samples were taken after the primary surgeon determined the resection cavity wall to be grossly normal and were analyzed using (1) true H&E, (2) SRM pseudo H&E, (3) immunohistochemical stains (IHC) for IDH1-R132H or p53. The sections were scored on a scale of 0–3 by a neuropathologist blinded to the corresponding results from each modality (0=no definite tumor cells; 1=rare tumor cells; 2=moderate tumor cells with preserved neuropil; 3 = abundant tumor cells). Positive and negative predictive values and Spearman correlation coefficients were calculated. RESULTS Ninety-one margin samples from 19 patients were included. Tumors were WHO grade II (29.7%), III (38.5%), and IV (31.8%). There was a strong correlation between SRM and H&E (Spearman correlation (r) = 0.76), SRM and IHC (r=0.81), and H&E and IHC scores (r=0.91). PPV of SRM score of 3 was 100%. The presence of tumor cells on SRM (scores 1–3) strongly correlated with the presence of tumor cells on H&E (PPV = 95%) and IHC (PPV = 91%). The absence of tumor cells on SRM correlated with absence of tumor on H&E and IHC only 10% and 50% (NPV) of the time, respectively. CONCLUSIONS The PPV of utilizing SRM to detect residual glioma cells in grossly normal resection cavity margins is high however the NPV is low. SRM may have utility as a rapid point-of-care intraoperative tool for identification of infiltrative glioma within resection cavity margins.

Conventional Anti-glioblastoma Chemotherapy Affects Proteoglycan Composition of Brain Extracellular Matrix in Rat Experimental Model in vivo.

Temozolomide (TMZ) is a conventional chemotherapy drug for adjuvant treatment of glioblastoma multiforme (GBM), often accompanied by dexamethasone (DXM) to prevent brain oedema and alleviate clinical side effects. Here, we aimed to investigate an ability of the drugs to affect normal brain tissue in terms of proteoglycan (PG) composition/content in experimental rat model in vivo. Age- and brain zone-specific transcriptional patterns of PGs were demonstrated for 8, 60, and 120 days old rats, and syndecan-1, glypican-1, decorin, biglycan, and lumican were identified as the most expressed PGs. DXM treatment affected both PG core proteins expression (mainly syndecan-1, glypican-1, decorin, biglycan, lumican, versican, brevican, and NG2) and heparan sulphate (HS)/chondroitin sulphate (CS) content in organotypic brain slice culture ex vivo and experimental animals in vivo in a dose-dependent manner. TMZ treatment did not result in the significant changes in PG core proteins expression both in normal rat brain hippocampus and cortex in vivo (although generics did), but demonstrated significant effects onto polysaccharide HS/CS content in the brain tissue. The effects were age- and brain zone-specific and similar with the age-related PGs expression changes in rat brain. Combination of TMZ with DXM resulted in the most profound deterioration in PGs composition and content in the brain tissue both at core protein and glycosaminoglycan levels. Taken together, the obtained results demonstrate that conventional anti-glioblastoma therapy affects proteoglycan structure and composition in normal brain tissue, potentially resulting in deterioration of brain extracellular matrix and formation of the favourable tumorigenic niche for the expansion of the residual glioma cells. During the TMZ chemotherapy, dose and regimen of DXM treatment matter, and repetitive low DXM doses seem to be more sparing treatment compared with high DXM dose(s), which should be avoided where possible, especially in combination with TMZ.

Neutrophil-Guided Drug Delivery for Targeting Residual Glioma Cells.

Neutrophil-Guided Drug Delivery for Targeting Residual Glioma Cells.

Antitumor efficacy of Lf modified daunorubicin plus honokiol liposomes in treatment of brain glioma

Malignant brain glioma is the most common and aggressive type of primary intracranial neoplasm. Regular chemotherapy cannot eradicate brain glioma cells and the residual glioma cells could form vasculogenic mimicry (VM) channels under hypoxic conditions to provide nutrients for tumor cell invasion. In addition, the existence of the blood-brain barrier (BBB) restricts most antitumor drugs into brain glioma. In this study, we developed a kind of lactoferrin (Lf) modified daunorubicin plus honokiol liposomes to transport antitumor drugs across BBB, eliminate the VM channels and block tumor cell invasion. The evaluations were performed on BBB model, brain glioma cells and glioma-bearing mice. In vitro results showed that the targeting liposomes with suitable physicochemical property could enhance the drug transportation acrossing the BBB, inhibit C6 cells invasion and destroy VM channels. Action mechanism studies indicated that Lf modified daunorubicin plus honokiol liposomes could activate apoptotic enzymes caspase 3 as well as down-regulate VM protein indicators (PI3K, MMP-2, MMP-9, VE-Cadherin and FAK). In vivo results displayed the targeting liposomes improved accumulation in brain tumor tissue and exhibited obvious antitumor efficacy. Therefore, Lf modified daunorubicin plus honokiol liposomes could be used as a potential therapy for treatment of brain glioma.

Therapeutic dormancy to delay postsurgical glioma recurrence: the past, present and promise of focal hypothermia.

Surgery precedes both radiotherapy and chemotherapy as the first-line therapy for glioma. However, despite multimodal treatment, most glioma patients die from local recurrence in the resection margin. Glioma surgery is inherently lesional, and the response of brain tissue to surgery includes hemostasis, angiogenesis, reactive gliosis and inflammation. Unfortunately, these processes are also associated with tumorigenic side-effects. An increasing amount of evidence indicates that the response to a surgery-related brain injury is hijacked by residual glioma cells and participates in the local regeneration of tumor tissues at the resection margin. Inducing therapeutic hypothermia in the brain has long been used to treat the secondary damage, such as neuroinflammation and edema, that are caused by accidental traumatic brain injuries. There is compelling evidence to suggest that inducing therapeutic hypothermia at the resection margin would delay the local recurrence of glioma by (i) limiting cell proliferation, (ii) disrupting the pathological connection between inflammation and glioma recurrence, and (iii) limiting the consequences of the functional heterogeneity and complexity inherent to the tumor ecosystem. While the global whole-body cooling methods that are currently used to treat stroke in clinical practice may not adequately treat the resection margin, the future lies in implantable focal microcooling devices similar to those under development for the treatment of epilepsy. Preclinical and clinical strategies to evaluate focal hypothermia must be implemented to prevent glioma recurrence in the resection margin. Placing the resection margin in a state of hibernation may potentially provide such a long-awaited therapeutic breakthrough.

The brain tissue response to surgical injury and its possible contribution to glioma recurrence.

Surgery is the first line therapy for glioma. However, glioma recurs in 90% of the patients in the resection margin. The impact of surgical brain injury (SBI) on glioma recurrence is largely overlooked. Herein, we review some of the mechanisms involved in tissue repair that may impact glioma recurrence at the resection margin. Many processes or molecules involved in tissue repair after brain injury are also critical for glioma growth. They include a wide array of secreted growth factors, cytokines and transcription factors including NFКB and STAT3 which in turn activate proliferative and anti-apoptotic genes and processes such as angiogenesis and inflammation. Because some residual glioma cells always remain in the tumor resection margin, there are now compelling arguments to suggest that some aspects of the brain tissue response to SBI can also participate to glioma recurrence at the resection margin. Brain tissue response to SBI recruits angiogenesis and inflammation that precede and then follow tumor recurrence at the resection margin. The healing response to SBI is double edged, as inflammation is involved in regeneration and healing, and has both pro- and anti-tumorigenic functions. A promising therapeutic approach is to normalize and re-educate the molecular and cellular responses at the resection margin to promote anti-tumorigenic processes involved in healing while inhibiting pro-tumorigenic activities. Manipulation of the inflammatory response to SBI to prevent local recurrence could also enhance the efficacy of other therapies such as immunotherapy. However, our current knowledge is far from sufficient to achieve this goal. Acknowledging, understanding and manipulating the double-edged role played by SBI in glioma recurrence is surely challenging, but it cannot be longer delayed.

Patient-specific biomathematical model to predict benefit of resection in human gliomas.

e13017 Background: Gliomas are incurable, primary brain tumors noted for their invasion of brain parenchyma. Our goal was to apply a biomathematical model to estimate the overall tumor invasiveness on an individual basis and determine whether the estimated number of residual glioma cells after resection of any extent is predictive of survival. Methods: Estimates of net rates of proliferation (ρ) and diffusion (D) of glioma cells, based on a biomathematical model of cell density, yield a ratio describing relative invasiveness (ρ/D). This metric was derived for 185 contrast enhancing gliomas from pretreatment MRIs. The residual MRI-detectable volume was combined with the ρ/D tuned to each patient's tumor to allow estimation of the number of glioma cells remaining post-resection. The patients were split into three cohorts by ρ/D values. Within each cohort, all possible cut-off values were considered as a possible threshold between low and high residual patient groups. Log-rank tests were performed for each possible threshold to determine if the Kaplan-Meyer curves were significantly different. Results: We demonstrate that for low ρ/D tumors there was no threshold of residual tumor cell population observed that could yield a significant survival benefit. Both the mid ρ/D and high ρ/D had robust thresholds of residual tumor cell population, below which patients saw significantly higher survival than patients with similar invasiveness and more residual tumor. Conclusions: These results suggest that our patient-specific biomathematical model-based estimates of tumor invasiveness and residual tumor cells have clinical utility in driving neurosurgical decision making. Given the physicians understanding of patient-specific risk factors such as tumor location, age, and physical health, an understanding of the differential surgical benefit allows for more informed cost-benefit analysis and improved quality of life. This metric enables physicians to identify a subset of patients who do not see a survival benefit from resection, making the operation potentially not worth the risks.

Future Approaches for the Therapy of Malignant Glioma: Targeting Genes Mediating Invasion

part of Malignant glioma is the most aggressive and consistently fatal of all brain cancers, without any effective therapies. The dismal prognosis of malignant gliomas is principally attributed to their highly invasive nature. The tumor enters into the surrounding normal brain tissue thus limiting complete removal by surgical resection and resulting in recurrence. A number of proteins and pathways have been implicated as being essential for glioma cell migration and invasion. Understanding the molecular mechanisms of glioma invasiveness is an essential step in developing rationally targeted effective therapies. Malignant gliomas (such as glioblastoma multi forme [GBM]) continue to cause a significant level of morbidity and mortality across a wide range of individuals. Gliomas, arising from astrocytes, are infiltrative and diffuse in nature and the most common and malignant of all human primary intracranial tumors. Irrespective of multimodal treatment, including debulking surgery, chemotherapy and radiation, patients with malignant glioma have a median survival rate of only 15 months [1]. The underlying reason for this dismal prognosis is the highly invasive nature of glioma into the brain parenchyma, resulting in recurrence even after aggressive surgical resection. The residual pool of invasive cells gives rise to recurrent tumors either immediately adjacent to the resection margins or within several centimeters of the resection cavity. Invading glioma cells routinely follow the white matter tracts and basement membranes of blood vessels. However, even though glioma cells penetrate into the glial region of the vascular basement membrane they lack the ability to disrupt/penetrate the endothelial basement membrane, thus confining the tumor growth within the CNS [2]. Glioma cell invasion involves a complex multistep process, including tumor cell interactions with the extracellular matrix (ECM) and with adjacent cells, tumor cell motility and proteolytic degradation of the ECM by tumor-secreted proteases, which is potentially controlled at each step by distinct genes and signaling pathways [3]. Therapies based on targeting these complex invasive processes have accomplished limited success, indicating that an increased understanding of the molecular mechanisms of glioma cell migration and invasion are mandatory for developing efficacious therapies to eradicate residual glioma cells following surgical resection. Several candidate genes, including members of the matrix metalloproteinase (MMP) gene family and their endogenous tissue inhibitors (TIMPs), have been recognized as regulators of glioma invasiveness. MMP-2 and MMP-9 have been extensively studied and are recognized as the most common and most expressed MMPs involved in glioma invasion [4]. MMPs enhance tumor cell invasion by degrading ECM proteins, activating signal-transduction cascades that promote motility and solubilizing ECM-bound growth factors [5]. Angiopoietin is overexpressed in invasive areas of glioblastoma and, in addition to promoting angiogenesis, also induces tumor cell infiltration by activating MMP-2 [6]. Marimastat is a low-molecular weight peptide mimetic inhibitor of MMPs [7]. Future approaches for the therapy of malignant glioma: targeting genes mediating invasion

Surgical impact on brain tumor invasion: A physical perspective

It is conventional strategy to treat highly malignant brain tumors initially with cytoreductive surgery followed by adjuvant radio- and chemotherapy. However, in spite of all such efforts, the patients' prognosis remains dismal since residual glioma cells continue to infiltrate adjacent parenchyma and the tumors almost always recur. On the basis of a simple biomechanical conjecture that we have introduced previously, we argue here that by affecting the 'volume-pressure' relationship and minimizing surface tension of the remaining tumor cells, gross total resection may have an inductive effect on the invasiveness of the tumor cells left behind. Potential implications for treatment strategies are discussed.