Targeting CD146 with a 64Cu-labeled antibody enables in vivo immunoPET imaging of high-grade gliomas

Given the highly heterogeneous character of brain malignancies and the associated implication for its proper diagnosis and treatment, finding biomarkers that better characterize this disease from a molecular standpoint is imperative. In this study, we evaluated CD146 as a potential molecular target for diagnosis and targeted therapy of glioblastoma multiforme (GBM), the most common and lethal brain malignancy. YY146, an anti-CD146 monoclonal antibody, was generated and radiolabeled for noninvasive positron-emission tomography (PET) imaging of orthotopic GBM models. ⁶⁴Cu-labeled YY146 preferentially accumulated in the tumors of mice bearing U87MG xenografts, which allowed the acquisition of high-contrast PET images of small tumor nodules (∼2 mm). Additionally, we found that tumor uptake correlated with the levels of CD146 expression in a highly specific manner. We also explored the potential therapeutic effects of YY146 on the cancer stem cell (CSC) and epithelial-to-mesenchymal (EMT) properties of U87MG cells, demonstrating that YY146 can mitigate those aggressive phenotypes. Using YY146 as the primary antibody, we performed histological studies of World Health Organization (WHO) grades I through IV primary gliomas. The positive correlation found between CD146-positive staining and high tumor grade (χ² = 9.028; P = 0.029) concurred with the GBM data available in The Cancer Genome Atlas (TCGA) and validated the clinical value of YY146. In addition, we demonstrate that YY146 can be used to detect CD146 in various cancer cell lines and human resected tumor tissues of multiple other tumor types (gastric, ovarian, liver, and lung), indicating a broad applicability of YY146 in solid tumors.About 23,000 new cases of brain and central nervous system tumors are expected to be diagnosed in 2015 in the United States alone (1). More importantly, 15,320 patients will likely die of brain cancer by the end of the year, the majority of them due to malignant tumors types (1, 2). Glioblastoma multiforme (GBM) is the most common brain malignancy, accounting for more than 45% of all primary malignant brain tumors. Incidence rates of GBM increase with age, peaking at ages between 75 and 84; as a result, the number of glioblastoma cases is expected to increase in the United States due to population aging (3). Amid the significant efforts devoted to find effective therapeutic strategies for the treatment of GBM, it remains an incurable disease with a dismal 5-y survival rate of only 5%.Recent understanding of the complex molecular mechanisms underlying GBM’s pathogenesis has revealed the considerable heterogeneity inherent to the disease and has led to the emergence of several promising, patient-tailored therapies (3, 4). However, these therapies benefit only a specific subset of patients and almost invariably need the implementation of combinatorial regimes that simultaneously target several tumor-associated pathways to avoid tumor recurrence and rapid development of resistance. Therefore, it is critical to find new relevant GBM molecular signatures that allow for better patient stratification into specific molecular subtypes and the design of effective targeted therapeutic agents. The creation of The Cancer Genome Atlas (TCGA), and with it the availability of invaluable cancer genome data, has been instrumental in creating the opportunity for researchers to explore the genomic profile of several malignancies and identify new targets that might allow the emergence of novel diagnostics and therapeutic paradigms. GBM was the first malignancy incorporated to TCGA for which extensive genomic and matched phenotypical and clinical data are available.We identified CD146 as a promising diagnosis and therapeutic target for GBM. Subsequent analysis of the TCGA data revealed a statistically significant correlation between the expression of CD146 and decreased disease-free survival and overall survival in glioblastoma patients (Fig. S1). Thus, we devoted our efforts to validate CD146 as a target for noninvasive diagnosis and stratification of GBMs and to evaluate its potential as a therapeutic target. CD146, also known as MCAM, Mel-CAM, MUC18, or S-endo1, was first identified as a tumor progression and metastasis marker in malignant melanomas (5, 6). The major roles of CD146 have been associated with intercellular and cell-matrix adhesion. However, its involvement in several other processes, including development, cell migration, signal transduction, stem cell differentiation, immune response, angiogenesis, and, more recently, induction of epithelial-mesenchymal transition (EMT), has also been documented (7, 8). Despite the copious body of data describing the expression of CD146 in a myriad of cancers, noninvasive in vivo molecular imaging of CD146 expression has remained unexplored.Open in a separate windowFig. S1. CD146 clinical relevance in glioblastoma multiforme patients. Clinical data were obtained from TCGA. (A) The table summarizes the demographics of the analyzed patient cohort. A Kaplan–Meier plot showing a significant difference in (B) disease-free survival (DFS) and (C) overall survival between CD146(+) and CD146(−) GBM patients. P values were determined by the log-rank test. Molecular imaging techniques such as positron emission tomography (PET) and fluorescence imaging are becoming indispensable tools to study tumor biology in a clinical setting (9). ImmunoPET, which combines the excellent sensitivity and quantification capabilities of PET with monoclonal antibodies’ (mAbs’) exquisite binding affinity and specificity for their cognate antigen, is one of the most valuable techniques (10, 11). In this study, we used an improved method to produce YY146, an mAb against human CD146, which we implemented as an immunoPET agent for noninvasive in vivo imaging of CD146 expression in an orthotopic GBM mouse model. We further investigated how CD146 expression associates with several stem cell-like and mesenchymal cell traits in tumor cells and determined the ability of YY146 to actuate preferentially on cell subpopulations presenting these aggressive phenotypes. Finally, histological analysis of different WHO grade human brain tumor tissue samples confirmed the clinical relevance of CD146 for diagnosis and stratification of high-grade glioma patients and suggested its feasibility as a target for YY146-based targeted therapies (e.g., YY146 alone or in combination with other drugs, radioimmunotherapy, antibody-drug conjugates, etc.).     

One hundred and fifty years of the Journal of Internal Medicine (JIM)

Systemic therapeutic efficacy is central to determining the outcome of patients with metastatic colorectal cancer (CRC). In these patients, there is a critical need for predictive biomarkers to optimize efficacy whilst minimizing toxicity. The integration of a new generation of molecularly targeted drugs into the treatment of CRC, coupled with the development of sophisticated technologies for individual tumours as well as patient molecular profiling, underlines the potential for personalized medicine. In this review, we focus on the latest progress made within the genomic and proteomic fields, concerning predictive biomarkers for individualized therapy in metastatic CRC.     

Approaching Biomarker Discovery through Genomics

The promise of genomic medicine lies in the ability to identify those factors that modify risk of disease at the individual level and, once identified, to be able to provide a personalized treatment or intervention to ablate the disease process. This concept is based upon a number of assumptions and current limitations that genomic science has yet to address. Critical to the development of personalized medicine is the determination of the genetic and epidemiologic cause of complex human disease, such as coronary heart disease, diabetes, asthma, and stroke. The risk factors that predispose an individual to any one of these disorders may not be unique, and the genomic profiles may be similar. Increasing the complexity of understanding the pathogenesis of these disorders is the growing recognition that the genetic risk factors likely interact not only with each other but also with poorly understood environmental factors. Ultimately, the prediction of an individual’s risk for any disorder will be determined by their genotype and their environmental exposures; however, in the absence of a defined genomic fingerprint, a subset of confirmed genetic risk factors can be used to help define biomarkers of disease. Clinically validated biomarkers can then serve as surrogates for the combined effects of genotype and environment and provide insights into disease pathogenesis.     

Cellular immunotherapy for high-grade glioma

The outcome for patients with the most common primary brain tumor, glioblastoma multiforme (GBM), remains poor. Several immunotherapeutic approaches are actively being pursued including antibodies and cell-based therapies. While the blood-brain barrier protects brain tumor cells from therapeutic antibodies, immune cells have the ability to traverse the blood-brain barrier and migrate into GBM tumors to exert their therapeutic function. Results of Phase I clinical studies with vaccines to induce GBM-specific T cells are encouraging and Phase II clinical trials are in progress. Nonvaccine-based cell therapy for GBM has been actively explored over the last four decades. Here we will review past clinical experience with adoptive cell therapies for GBM and summarize current strategies on how to improve these approaches.     

Personalized medicine strategies for managing patients with Parkinsonism and cognitive deficits

Patients exhibiting the classic manifestations of parkinsonism – tremors, rigidity, postural instability, slowed movements and, sometimes, sleep disturbances and depression – may also display severe cognitive disturbances. All of these particular motoric and behavioral symptoms may arise from Parkinson's disease [PD] per se, but they can also characterize Lewy Body dementia [LBD] or concurrent Parkinson's and Alzheimer's diseases [PD & AD]. Abnormalities of both movement and cognition are also observed in numerous other neurologic diseases, for example Huntington's Disease and the frontotemporal dementia. Distinguishing among these diseases in an individual patient is important in “personalizing” his or her mode of treatment, since an agent that is often highly effective in one of the diagnoses (e.g., l-dopa or muscarinic antagonists in PD) might be ineffective or even damaging in one of the others. That such personalization, based on genetic, biochemical, and imaging-based biomarkers, is feasible is suggested by the numerous genetic abnormalities already discovered in patients with parkinsonism, Alzheimer's disease and Huntington's disease (HD) and by the variety of regional and temporal patterns that these diseases can produce, as shown using imaging techniques.     

Phase II study of combined carmustine, 5-fluorouracil, hydroxyurea, and 6-mercaptopurine (BFHM) for the treatment of malignant gliomas

The Neuro-oncology Service of the University of California Brain Tumor Research Center conducted a nonrandomized phase II study to evaluate, in patients with recurrent malignant glioma, the benefit of a four-drug combination (BFHM) consisting of carmustine (1,3-bis (2-chloroethyl)-1-nitrosourea), 5-fluorouracil, hydroxyurea, and 6-mercaptopurine. There were 29 evaluable glioblastoma multiforme patients and 45 nonglioblastoma anaplastic glioma patients available for analysis. Tumor progression was analyzed as the primary study endpoint. Of the glioblastoma patients, 16 of 29 (55%) responded or stabilized on therapy; of the other anaplastic gliomas, 32 of 45 (71%) responded or stabilized. For patients who stabilized or responded to treatment, BFHM achieved a median time to tumor progression of 46 weeks with a 25th percentile time to tumor progression of 68 weeks for anaplastic gliomas and a median time to tumor progression of 23 weeks with a 25th percentile time to tumor progression of 36 weeks for glioblastoma multiforme patients. A Cox multivariate analysis demonstrated that age and Karnofsky score were important prognostic variables for these patients.     

Alternative lengthening of telomeres and survival in patients with glioblastoma multiforme

Despite advances in the molecular pathogenesis of glioblastoma multiforme, no reliable prognostic markers have been identified. We analysed telomerase activity and telomere lengths in glioblastoma multiformes from 77 patients. 19 patients (25%) had tumours with the alternative-lengthening-of-telomere (ALT) phenotype. Median survival for patients with this phenotype was 542 days (95% CI 114-970) compared with 247 days (224-270) for glioblastoma multiformes with normal telomeres (p=0.0003). Cox's regression analysis showed that this association is independent of age. In patients with non-ALT tumours, telomerase activity did not affect survival (median 287 [199-375] vs 236 [230-242] days, p=0.275). We conclude that ALT is a prognostic indicator for patients with glioblastoma multiforme.     

Evaluation of an imaging biomarker,Dixon quantitative chemical shift imaging,in Gaucher disease: lessons learned

Gaucher disease (GD) is the first lysosomal storage disorder for which specific therapy became available. The infiltration of bone marrow by storage cells plays an important part in the pathophysiology of skeletal complications and can be quantified by measurements of bone marrow fat fraction (Ff). Ff measurements by Dixon quantitative chemical shift imaging (QCSI) are standard for the follow-up care of GD patients at the Academic Medical Center. Several criteria should be met in order for these measurements to qualify as an imaging biomarker. These include: 1) The presence of the imaging biomarker is closely coupled or linked to the presence of the target disease or condition; 2) The detection and/or quantitative measurement of the biomarker is accurate, reproducible, and feasible over time, and; 3) The changes measured over time in the imaging biomarker are closely coupled, or linked, to the success or failure of the therapeutic effect and the true end point for the medical therapy being evaluated. This review assesses the use of Ff measurements by QCSI as a biomarker for GD in light of these criteria. In addition potential pitfalls are discussed including: degenerative disc disease; vertebral collapse and infection; haematological malignancies; focal fatty deposits; age; menopause; phase and repositioning errors, and; fat surrounding the basivertebral vein. QCSI measurements of Ff can be used as an imaging biomarker for GD taking these pitfalls into account. It is one of the first biomarkers, in particular imaging biomarkers, for GD that has been systematically evaluated and could be a valuable tool in clinical trials comparing different treatments or dosing regimens.     

Recurrence pattern in glioblastoma multiforme patients treated with anti-angiogenic chemotherapy

Purpose  Glioblastoma multiforme is the prototype of an angiogenic tumour. Under experimental conditions, anti-angiogenic therapy strategies lead to an increased invasion. Here we report on the pattern of tumour recurrence in glioblastoma patients treated with an anti-angiogenic chemotherapy. Patients and methods  A total of 32 patients with glioblastoma multiforme and a residual tumour mass after operation were treated with a continuous low-dose chemotherapy with temozolomide and a COX-II inhibitor, a presumably anti-angiogenic therapy. Results  While anti-tumour activity of this therapy regimen was excellent with a mean overall time to progression of 10.4 (±0.9) months and a mean overall survival of 17.8 (±1.5) months, an unusually high rate of distant recurrences was observed (62.5%). Conclusion  Patients treated with an anti-angiogenic chemotherapy experience distant recurrences at a higher rate than reported for conventional therapies. This may reflect an anti-angiogenic therapy-induced activation of glioma invasion confirming similar recently published experimental results.     

RET-protooncogene variants in patients with sporadic neoplasms of the digestive tract and the central nervous system

Purpose

The RET protooncogene plays a crucial role in neural crest development; accordingly, mutations of RET cause MEN2A and familial medullary thyroid carcinoma, while the expression deregulation of RET is involved in the pathophysiology of glioblastoma multiforme (GBM) and pancreatic cancer (PDAC). The aim of this study was to evaluate if germline variants of the RET protooncogene are associated with GBM, pancreatic cancer and gastric cancer (GC).

Methods

Genomic DNA from peripheral blood was isolated from 100 patients with GBM, 65 patients with GC and 54 patients with PDAC. The coding sequence of RET promoter, exon 2 and exon 13 was amplified. Sequence variations at ?5 and ?1 in the promotor and in exon 2 were determined through a LightCycler assay, and analysis of exon 13 was carried out by genomic sequencing.

Results

There was no significant association of the RET-promoter or exon 2 genotypes with the phenotype in the different populations, although there was an increase of the GG genotype of the ?5G>A variant in all cancers compared to controls. Sequencing of exon 13 identified mutation c.2372A>T in codon 791 (Y791F) in heterozygous state in one of 100 GBM patients, in two of 65 patients with gastric cancer, in two of 54 PDAC patients and in none of the controls.

Conclusions

Although our data did not reach significance in our small cohorts, we cannot rule out the involvement of the ?5G promoter allele and the c.2372A>T mutation in the development of the aforementioned tumours.     

Calcified Neurocysticercosis Associates with Hippocampal Atrophy: A Population-Based Study

Calcified neurocysticercosis has been associated with hippocampal atrophy in patients with refractory epilepsy, but the relevance of this association in the population at large is unknown. We assessed calcified cysticerci and its association with hippocampal atrophy in elderly persons living in Atahualpa, an Ecuadorian village endemic for neurocysticercosis. All Atahualpa residents ≥ 60 years of age were invited to undergo computed tomography/magnetic resonance imaging for neurocysticercosis detection. Twenty-eight (11%) out of 248 enrolled persons had calcified cysticerci (case-patients) and were matched 1:1 by age, sex, and years of education to individuals without neurocysticercosis on computed tomography/magnetic resonance imaging (controls). Four case-patients and none of the controls had epilepsy (P = 0.134). Cognitive performance was similar across both groups. The Scheltens'' medial temporal atrophy scale was used for hippocampal rating in case-patients and matched controls without neurocysticercosis. Mean score in the Scheltens'' scale was higher in case-patients than in controls (P < 0.001). Atrophic hippocampi were noticed in 19 case-patients and five controls (P = 0.003). Atrophy was bilateral in 11 case-patients and unilateral in eight. All case-patients with unilateral hippocampal atrophy had at least one ipsilateral calcification. This study shows an association between calcified cysticerci and hippocampal atrophy and raises the possibility of an inflammation-mediated hippocampal damage as the responsible mechanism for these findings.     

The challenge of intratumour heterogeneity in precision medicine

Cells within tumours have diverse genomes and epigenomes and interact differentially with their surrounding microenvironment generating intratumour heterogeneity, which has critical implications for treating cancer patients. Understanding the cellular and microenvironment composition and characteristics in individual tumours is critical to stratify the patient population that is likely to benefit from specific treatment regimens. Here, we will review the current understanding of intratumour heterogeneity at the genomic, epigenomic and microenvironmental levels. We will also discuss the clinical implications and the challenges posed by intratumour heterogeneity and evaluate noninvasive methods such as circulating biomarkers to characterize the cellular diversity of tumours. Comprehensive assessment of the molecular features of patients based on tumour specimen characterization (including intratumour spatial and temporal variations), ancillary noninvasive methods (such as circulating biomarkers and molecular imaging approaches) and the correct design of clinical trials are required to guide administration of targeted therapy and to control therapeutic resistance. Finding the means to accurately determine and effectively control tumour heterogeneity and translate these achievements into patient benefit are major goals in modern oncology.     

Chemotherapy for malignant brain tumors of astrocytic and oligodendroglial lineage

To date, surgery and irradiation remain the standard therapies for anaplastic astrocytoma (AA, WHO grade III) and glioblastoma multiforme (GBM, WHO grade IV). Due to infiltrative tumor growth a complete surgical resection is never achieved and more than 90% of the tumors will recur within 2 cm of the primary tumor location. Postoperative radiotherapy prolongs survival but is not curative and prognosis remains poor with only a few patients being alive 2 years after diagnosis. Over the past decades multiple trials dealt with the question of whether chemotherapy (CT) may influence the outcome of malignant brain tumor patients. In general, the results have been disappointing with one exception: chemosensitivity and prolonged survival after CT have been demonstrated for tumors of oligodendrogial lineage. Drugs showing some activity in malignant brain tumors and therapeutic concepts will be discussed. Received: 2 May 2000 / Accepted: 28 May 2000     

Pattern of retinoblastoma pathway inactivation dictates response to CDK4/6 inhibition in GBM

Glioblastoma multiforme (GBM) is a fatal primary brain tumor harboring myriad genetic and epigenetic alterations. The recent multidimensional analysis of the GBM genome has provided a more complete view of the landscape of such alterations and their linked pathways. This effort has demonstrated that certain pathways are universally altered, but that the specific genetic events altered within each pathway can vary for each particular patient''s tumor. With this atlas of genetic and epigenetic events, it now becomes feasible to assess how the patterns of mutations in a pathway influence response to drugs that are targeting such pathways. This issue is particularly important for GBM because, in contrast to other tumor types, molecularly targeted therapies have failed to alter overall survival substantially. Here, we combined functional genetic screens and comprehensive genomic analyses to identify CDK6 as a GBM oncogene that is required for proliferation and viability in a subset of GBM cell lines and tumors. Using an available small molecule targeting cyclin-dependent kinases (CDKs) 4 and 6, we sought to determine if the specific pattern of retinoblastoma pathway inactivation dictated the response to CDK4/6 inhibitor therapy. We showed that codeletion of CDKN2A and CDKN2C serves as a strong predictor of sensitivity to a selective inhibitor of CDK4/6. Thus, genome-informed drug sensitivity studies identify a subset of GBMs likely to respond to CDK4/6 inhibition. More generally, these observations demonstrate that the integration of genomic, functional and pharmacologic data can be exploited to inform the development of targeted therapy directed against specific cancer pathways.     

Two rare complications of glioblastoma multiforme: persistent hiccup and acquired haemophilia A

A 69-year-old man was admitted to the hospital with persistent hiccups. Computed tomography and magnetic resonance imaging of the brain were performed and revealed a glioblastoma multiforme localised in the right temporal lobe. After resection, the hiccups disappeared, suggesting that temporal areas are involved in control mechanisms of hiccups. A month later, the patient was readmitted because of skin, mucosal and soft tissue bleedings. Laboratory findings showed a prolonged aPTT, a low factor VIII activity and a factor VIII inhibitor, leading to the diagnosis of acquired haemophilia A. Acquired haemophilia A is a potentially life-threatening haemorrhagic disorder resulting from the presence of antibodies against factor VIII. We believe that this disorder developed due to exposure of factor VIII(-like) tumour antigens to the immune system. This case illustrates two yet unknown complications of a glioblastoma multiforme: persistent hiccups and acquired haemophilia A.     

A randomized trial of patient self-managed versus physician-managed oral anticoagulation

BACKGROUND: Self-management (SM) of warfarin by patients is an attractive strategy, particularly if it improves anticoagulation control and can be done safely under minimal physician supervision. OBJECTIVE: To compare the effect of SM with physician-management (PM) on the maintenance of therapeutic anticoagulation. METHODS: A randomized, open-label eight-month trial was performed. Patients 18 years of age and older were eligible if they were receiving warfarin for at least one month before enrolment and required anticoagulation for at least one year to a target international normalized ratio (INR) of 2.0 to 3.0 or 2.5 to 3.5. Exclusion criteria were a known hypercoaguable disorder, mental incompetence, a language barrier or an inability to attend training sessions. Patients randomly assigned to SM tested their INR using a point-of-care device (Pro Time Microcogulation System, International Technidyne Corporation, USA) and adjusted their warfarin doses using a nomogram. Patients randomly assigned to PM received usual care from their general practitioner. The primary outcome was to demonstrate 20% improvement in anticoagulation control by SM. RESULTS: One hundred forty patients were randomly assigned (70 per group). Thirteen patients dropped out of SM early due to an inability to self-manage. Based on intention-to-treat analysis, there was no difference in the proportion of INR in range (SM 64.8% versus PM 58.7%, P=0.23) or time in target range (SM 71.8% versus PM 63.2%, P=0.14). Patients managing their own therapy spent less time below the therapeutic range (15.0% versus 27.3%, P=0.04). There were three major complications of thrombosis or bleeding, all occurring in the PM arm. All patients who completed SM preferred to continue with that strategy. CONCLUSIONS: SM was not significantly better than PM in maintaining therapeutic anticoagulation. SM was feasible and appeared safe in the present study population.     

An Update on Parkinson's Disease: Improving Patient Outcomes

Neurologists are faced with many challenges in caring for patients with Parkinson's disease (PD). This chronic, long-term illness that affects at least one million people in the United States requires a coordinated healthcare partnership between the physician and the patient. The importance of early diagnosis is essential to delaying disease progression and early diagnosis and intervention may be aided by recent advances in biomarkers, genomics, and imaging. A misdiagnosis or late diagnosis will lead to deteriorating patient health. Additionally, physicians should incorporate current guidelines into their treatment strategies, and awareness of the reasoning behind these guidelines is critical for appropriate use. Physicians should be up to date on identifying the most appropriate therapies based on emerging science and disease staging, and should implement patient education into their practice. Due to limitations for currently available therapies, adjunctive therapies may lead to improved outcomes in patients with PD. The use of multiple therapies can improve myriad symptoms, more so than a monotherapy. Knowledge of these therapies is critical to achieving best outcomes in patients with PD.     

Management of intermediate‐risk pulmonary embolism: uncertainties and challenges

Current guidelines on the treatment of acute pulmonary embolism (PE) recommend stratification of hemodynamically stable patients in ‘low risk’ and ‘intermediate risk’. Validated risk scores, cardiac biomarkers, and imaging of the right ventricle all help in distinguishing both patient categories. The relevance of this risk stratification lies in the determination of the most optimal treatment for the individual patient. In this clinical review, we will discuss how patients with ‘intermediate‐risk’ PE can be identified as well as recent advances in their therapeutic management. Based on a clinical case, we will highlight the indications for reperfusion therapy and the current experience with non‐vitamin K‐dependent oral anticoagulant (NOACs) in this specific patient's category.