RESUMO
It has been hypothesized that persistent ketotic hypoglycemia represents a potential therapeutic strategy against high-grade gliomas. Perillyl alcohol (POH) is a non-toxic, naturally-occurring, hydroxylated monoterpene that exhibits cytotoxicity against temozolomide-resistant glioma cells, regardless of O6-methylguanine-methyltransferase promoter methylation status. The present study aimed to evaluate the toxicity and therapeutic efficacy of intranasal POH when administered in combination with a ketogenic diet (KD) program for the treatment of patients with recurrent glioblastoma. The 32 enrolled patients were divided into two groups, KD or standard diet, with intranasal POH treatment (n=17 and n=15, respectively). The nutritional status and anthropometric parameters of the patients were measured. Patients that adhered to the KD maintained a strict dietary regimen, in addition to receiving 55 mg POH four times daily, in an uninterrupted administration schedule for three months. Neurological examination and magnetic resonance imaging analysis were used to monitor disease progression. A total of 9/17 patients in the KD group survived and maintained compliance with the KD. After three months of well-tolerated treatment, a partial response (PR) was observed for 77.8% (7/9) of the patients, stable disease (SD) in 11.1% (1/9) and 11.1% (1/9) presented with progressive disease (PD). Among the patients assigned to the standard diet group, the PR rate was 25% (2/8 patients), SD 25% (2/8) and PD 50% (4/8 patients). The patients assigned to the KD group presented with reduced serum lipid levels and decreased low-density lipoprotein cholesterol levels. These results are encouraging and suggest that KD associated with intranasal POH may represent a viable option as an adjunct therapy for recurrent GBM.
RESUMO
Introduction Monoterpene perillyl alcohol (POH) is cytotoxic to temozolomideresistant glioma cells, regardless of its O6-methylguanine-methyltransferase (MGMT) promoter methylation status. Moreover, adherence to a ketogenic diet (KD) produced successful outcomes in preclinical and clinical studies in the glioma setting. Case Presentation A 54-year-old Caucasian man had a confirmed diagnosis of refractory glioblastoma multiforme (GBM). The immunohistochemical evaluation was negative for methylation, and failed to detect mutations in the isocitrate dehydrogenase (IDH) 1 and 2 genes. In January 2016, the patient was enrolled in a clinical trial combining daily intranasal delivery of POH in combination with a KD. The KD was administered concomitantly with inhalation of POH (55 mg, 4 times a day) in an uninterrupted administration schedule for 3 months. Results The combination treatment was well-tolerated. The nutritional status and anthropometric measurements of the patient were measured. Adherence to the KD was confirmed by measuring the levels of ketone bodies in the urine. Throughout the treatment, a reduced frequency of seizures was observed. After three months of adherence to the treatment, the patient presented with weight loss, reduced body fat, increased water retention, and a slight increase in bone and muscle mass. A follow-up magnetic resonance imaging (MRI) scan after 3 months of treatment revealed marked reduction of the enhancing lesion. Conclusion Intranasal delivery of POH combined with concomitant adherence to a KD appeared to have a beneficial therapeutic effect in a patient with recurrent GBM. Further studies are needed to evaluate the efficacy of this therapeutic strategy in a larger cohort of treatment-refractory GBM patients.
Introdução O monoterpeno álcool perílico (AP) é citotóxico para linhagens celulares de glioblastoma, independentemente do status do promotor de metilação O6-metilguaninametiltransferase (MGMT). Além disso, a adesão à dieta cetogênica (DC) produziu resultados bem sucedidos em desenho de estudos pré-clínicos e clínicos de glioma. Relato de Caso Homem, 54 anos, caucasiano, com diagnóstico de glioblastoma multiforme (GBM) recidivo. A avaliação imuno-histoquímica foi negativa para metilação e não detectou mutações do gene da isocitrato desidrogenase 1 e 2 (IDH1 IDH2). Em janeiro de 2016, o paciente foi inscrito em um ensaio clínico da administração intranasal diária do AP combinada a DC. A DC foi administrada concomitantemente com inalação de AP (55 mg, 4 vezes ao dia) em um cronograma de administração ininterrupto durante 3 meses. Resultados O tratamento combinado foi bem tolerado. O estado nutricional e as medidas antropométricas do paciente foram avaliadas. Aderência a DC foi confirmada pela presença de corpos cetônicos na urina. Ao longo do tratamento, observou-se redução da frequência de convulsões. Após três meses de adesão ao tratamento, o paciente apresentou perda de peso, redução da gordura corporal, melhor hidratação e um aumento discreto da massa óssea e muscular. O acompanhamento da ressonância magnética após 3 meses de tratamento revelou redução acentuada do volume da lesão. Conclusão A administração intranasal do AP combinada a DC sugere ter um efeito terapêutico benéfico em pacientes com GBM recorrente. São necessários mais estudos para avaliar a eficácia desta estratégia terapêutica em uma coorte maior de pacientes com GBM refratários.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Glioblastoma , Dieta Cetogênica , Administração Intranasal , MonoterpenosRESUMO
Monoterpenes such as limonene and perillyl alcohol (POH) are promising natural compounds with pro-oxidant properties partly due to endoplasmic reticulum (ER) stress-induced cytotoxicity, and antioxidant activity owing to their activity as free radical scavengers, inhibition of coenzyme Q synthesis, activation of antioxidant-responsive elements (inducing detoxification enzymes) and induction of apoptosis. Activation of ER-stress responses generates reactive oxygen species (ROS), which are highly reactive free radicals mainly produced during mitochondrial electron transfer for adenosine triphosphate (ATP) synthesis. When cells are subjected to oxidative stress conditions, there is an accumulation of ROS that can lead to irreversible cell injury caused primarily by lipid peroxidation, protein aggregation and/or DNA damage. Malignant tumors, such as glioblastoma multiforme, display elevated rates of oxygen consumption, necrosis and abnormal structural microvasculature. Alterations in the tumor microenvironment are tightly linked to tumor progression and occur as a result of activation of complex signaling networks involving inter-clonal cooperation, cell-matrix interactions and an ongoing inflammatory response leading to genetic and epigenetic alterations. This review will focus on the pro- and anti-oxidant activities of POH, which are greatly dependent on the respective ROS levels within the tumor microenvironment and involve the ER stress response system. As well, some critical aspects of tumor-associated metabolic changes and the consequences of endogenous ROS production for tumor progression will be discussed.
Assuntos
Antineoplásicos/metabolismo , Neoplasias Encefálicas/metabolismo , Sequestradores de Radicais Livres/metabolismo , Glioblastoma/metabolismo , Monoterpenos/metabolismo , Animais , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Carcinogênese , Estresse do Retículo Endoplasmático , Sequestradores de Radicais Livres/uso terapêutico , Glioblastoma/tratamento farmacológico , Humanos , Hipóxia , Peroxidação de Lipídeos , Monoterpenos/uso terapêutico , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Microambiente Tumoral , Resposta a Proteínas não DobradasRESUMO
BACKGROUND: Gliomas display a high degree of intratumor heterogeneity, including changes in physiological parameters and lipid composition of the plasma membrane, which may contribute to the development of drug resistance. Biophysical interactions between therapeutic agents and the lipid components at the outer plasma membrane interface are critical for effective drug uptake. Amphipathic molecules such as perillyl alcohol (POH) have a high partition coefficient and generally lead to altered lipid acyl tail dynamics near the lipid-water interface, impacting the lipid bilayer structure and transport dynamics. We therefore hypothesized that glioma cells may display enhanced sensitivity to POH-induced apoptosis due to plasma membrane alterations, while in non-transformed cells, POH may be expelled through thermal agitation. METHODS: Interactions between POH and the plasma membrane was studied using molecular dynamics simulations. In this phase I/II trial, we set up to evaluate the clinical effectiveness of long-term (up to 5 years) daily intranasal administration of POH in a cohort of 19 patients with low-grade glioma (LGG). Importantly, in a series of clinical studies previously published by our group, we have successfully established that intranasal delivery of POH to patients with malignant gliomas is a viable and effective therapeutic strategy. RESULTS: POH altered the plasma membrane potential of the lipid bilayer of gliomas and prolonged intranasal administration of POH in a cohort of patients with LGG halted disease progression with virtually no toxicity. CONCLUSION: Altogether, the results suggest that POH-induced alterations of the plasma membrane might be contributing to its therapeutic efficacy in preventing LGG progression.