Roberta Ranieri

Cannabidiol: State of the art and new challenges for therapeutic applications

Over the past years, several lines of evidence support a therapeutic potential of Cannabis derivatives and in particular phytocannabinoids. Δ9-THC and cannabidiol (CBD) are the most abundant phytocannabinoids in Cannabis plants and therapeutic application for both compounds have been suggested. However, CBD is recently emerging as a therapeutic agent in numerous pathological conditions since devoid of the psychoactive side effects exhibited instead by Δ9-THC. In this review, we highlight the pharmacological activities of CBD, its cannabinoid receptor-dependent and -independent action, its biological effects focusing on immunomodulation, angiogenetic properties, and modulation of neuronal and cardiovascular function. Furthermore, the therapeutic potential of cannabidiol is also highlighted, in particular in nuerological diseases and cancer.

Endocannabinoid System in Neurological Disorders

BACKGROUND Several studies support the evidence that the endocannabinoid system and cannabimimetic drugs might have therapeutic potential in numerous pathologies. These pathologies range from neurological disorders, atherosclerosis, stroke, cancer to obesity/metabolic syndrome and others. METHODS In this paper we review the endocannabinoid system signaling and its alteration in neurodegenerative disorders like multiple sclerosis, Alzheimers disease, Parkinsons disease and Huntingtons disease and discuss the main findings about the use of cannabinoids in the therapy of these pathologies. RESULTS Despite different etiologies, neurodegenerative disorders exhibit similar mechanisms like neuro-inflammation, excitotoxicity, deregulation of intercellular communication, mitochondrial dysfunction and disruption of brain tissue homeostasis. Current treatments ameliorate the symptoms but are not curative. Interfering with the endocannabinoid signaling might be a valid therapeutic option in neuro-degeneration. To this aim, pharmacological intervention to modulate the endocannabinoid system and the use of natural and synthetic cannabimimetic drugs have been assessed. CB1 and CB2 receptor signaling contributes to the control of Ca2+ homeostasis, trophic support, mitochondrial activity, and inflammatory conditions. CONCLUSION Several studies and patents suggest that the endocannabinoid system has neuro-protective properties and might be a target in neurodegenerative diseases.

N6-isopentenyladenosine dual targeting of AMPK and Rab7 prenylation inhibits melanoma growth through the impairment of autophagic flux

Targeting the autophagic process is considered a promising therapeutic strategy in cancer since a great number of tumors, including melanoma, show high basal levels of protective autophagy that contributes to tumor progression and chemoresistance. Here, exploiting both in vitro and in vivo approaches, we identified N6-isopentenyladenosine (iPA), an end product of the mevalonate pathway, as a novel autophagy inhibitor with an interesting anti-melanoma activity. iPA, after being phosphorylated by adenosine kinase into 5′-iPA-monophosphate, induces autophagosome accumulation through AMPK activation, measured by increased fluorescent GFP-LC3 puncta and enhanced conversion into the lipidated autophagosome-associated LC3-II. However, at a later stage iPA blocks the autophagic flux monitored by p62 accumulation, Luciferase reporter-based assay for LC3 turnover in living cells and fluorescence of a tandem RFP-GFP-LC3 construct. Impaired autophagic flux is due to the block of autophagosome–lysosome fusion through the defective localization and function of Rab7, whose prenylation is inhibited by iPA, resulting in a net inhibition of autophagy completion that finally leads to melanoma apoptotic cell death. AMPK silencing prevents apoptosis upon iPA treatment, whereas basal autophagosome turnover is still inhibited due to unprenylated Rab7. These results strongly support the advantage of targeting autophagy for therapeutic gain in melanoma and provide the preclinical rational to further investigate the antitumor action of iPA, able to coordinately induce autophagosome accumulation and inhibit the autophagic flux, independently targeting AMPK and Rab7 prenylation. This property may be particularly useful for the selective killing of tumors, like melanoma, that frequently develop chemotherapy resistance due to protective autophagy activation.

Deregulated expression and activity of Farnesyl Diphosphate Synthase (FDPS) in Glioblastoma

Glioblastoma (GBM), the most aggressive brain cancer, is highly dependent on the mevalonate (MVA) pathway for the synthesis of lipid moieties critical for cell proliferation but the function and regulation of key intermediate enzymes like farnesyl-diphosphate synthase (FDPS), up to now, remained unknown. A deregulated expression and activity of FDPS was the central research idea of the present study. FDPS mRNA, protein and enzyme activity were analyzed in a cohort of stage III-IV glioma patients (N = 49) and primary derived cells. FDPS silencing helped to clarify its function in the maintenance of malignant phenotype. Interestingly, compared to tumor-free peripheral (TFB) brain and normal human astrocytes (NHA), FDPS protein expression and enzyme activity were detected at high degree in tumor mass where a correlation with canonical oncogenic signaling pathways such as STAT3, ERK and AKT was also documented. Further, FDPS knockdown in U87 and GBM primary cells but not in NHA, enhanced apoptosis. With the effort to develop a more refined map of the connectivity between signal transduction pathways and metabolic networks in cancer FDPS as a new candidate metabolic oncogene in glioblastoma, might suggest to further target MVA pathway as valid therapeutic tool.

The isoprenoid derivative N6‐benzyladenosine CM223 exerts antitumor effects in glioma patient‐derived primary cells through the mevalonate pathway

N6‐Isopentenyladenosine (i6A) is a modified nucleoside exerting in vitro and in vivo antiproliferative effects. We previously demonstrated that the actions of i6A correlate with the expression and activity of farnesyl pyrophosphate synthase (FPPS), a key enzyme involved in the mevalonate (MVA) pathway, which is aberrant in brain cancer. To develop new anti‐glioma strategies, we tested related compounds exhibiting greater activity than i6A.

Phytocannabinoids and Cannabimimetic Drugs: Recent Patents in Central Nervous System Disorders.

BACKGROUND Starting from the chemical structure of phytocannabinoids, isolated from Cannabis sativa plant, research groups designed numerous cannabimimetic drugs. These compounds according to their activities can be partial, full agonists and antagonists of cannabinoid receptors. Anecdotal reports and scientific studies described beneficial properties of cannabinoids and their derivatives in several pathological conditions like neurological and neuropsychiatric disorders, and in many other diseases ranging from cancer, atherosclerosis, stroke, hypertension, inflammatory related disorders, and autoimmune diseases. METHODS In this study, starting from the endocannabinoid mechanism of action in neuronal signaling, we highlight and discuss potential application and recent patents of cannabimimetic drugs in neurological disorders. RESULTS The cannabinoid CB1 receptor was considered particularly interesting for therapeutic approaches in neurological diseases, because primarily expressed by neurons of the central nervous system. In many experimental models, these drugs act via this receptor, however, CB1 receptor independent mechanisms have been also described. Furthermore, endogenous ligands of cannabinoid receptors, the endocannabinoids, are potent modulators of the synaptic function in the brain. In neurological diseases, numerous studies reported modulation of the levels of endocannabinoids according to the phase of the disease and its progression. CONCLUSIONS Finally, although the study of the mechanisms of action of these compounds is still unsolved, many reports and patents strongly suggest therapeutic potential of these compounds in neurological diseases.

Recognition by natural killer cells of N6-isopentenyladenosine-treated human glioma cell lines

Cancer cell stress induced by cytotoxic agents promotes antitumor immune response. Here, we observed that N6‐isopentenyladenosine (iPA), an isoprenoid modified adenosine with a well established anticancer activity, was able to induce a significant upregulation of cell surface expression of natural killer (NK) cell activating receptor NK Group 2 member D (NKG2D) ligands on glioma cells in vitro and xenografted in vivo. Specifically suboptimal doses of iPA (0.1 and 1 µM) control the selective upregulation of UL16‐binding protein 2 on p53wt‐expressing U343MG and that of MICA/B on p53mut‐expressing U251MG cells. This event made the glioblastoma cells a potent target for NK cell‐mediated recognition through a NKG2D restricted mechanism. p53 siRNA‐mediated knock‐down and pharmacological inhibition (pifithrin‐α), profoundly prevented the iPA action in restoring the immunogenicity of U343MG cells through a mechanism that is dependent upon p53 status of malignancy. Furthermore, accordingly to the preferential recognition of senescent cells by NK cells, we found that iPA treatment was critical for glioma cells entry in premature senescence through the induction of S and G2/M phase arrest.

Brain cancer risk: the weight of obesity

of the MVA pathway including HMGCoA reductase, MVA kinase and farnesyl diphosphate farnesyl transferase and p53 status in GBM. Adipose-tissue-derived mesenchymal stem cells (AT_MSCs) have been seen to promote the aggressive growth of co-cultured GBM cell. Moreover, highly vascularized tumors developed when AT-MSC and GBM were co-transplanted in vivo [2]. For this reason we should consider that the intrinsic lipid metabolic reprogramming in glioma development is not necessarily linked to tissue obesity. Glioma grows inside the brain rather than in the lining and is much more likely to be insensitive to adipokines, growth factors, steroid hormones and inflammatory cyto/chemokines released by the adipose tissue that are known to play a key role in the mechanisms linking adiposity to malignancy. It should not surprise that adiposity is uniquely related to enhanced risk for meningiomas which grow at the external margins of the brain and spinal cord often adjacent to abdominal fat, and this type of brain tumor is the only one directly linked to an increased risk for cancer in the presence of overweight/obesity. In addition, an hyperactivation of meningeal macrophages in the CNS has been associated to the fatigue and muscle damage often induced by the effect of excess weight on muscle, joints and spinal cord [3]. As inflammation’s dark side is a powerful force in cancer development, we think that this obesity related-inflammatory milieu may be an additional explanatory reason for obesity and meningioma link. Indeed, immuno-metabolism, the confluence of metabolism and immune activation has emerged as a chief breakthrough in diseased brain. For glioma, while a clear link between obesity and cancer is still lacking, we suggest to pay attention to the glucose metabolic pathways’ alteration. Dysregulated metabolism that stems from inflamed adipose tissue in obesity may include not only dyslipidemia but also insulin resistance and hyperglycemia. These may impact the To the Editor,

Cannabinoids and Neuro-Inflammation: Regulation of Brain Immune Response.

BACKGROUND Cannabinoid receptors are involved in the neuro-pathogenic mechanisms of inflammatory conditions of the central nervous system and their expression can be modulated during diseases. METHODS In this manuscript we highlight the function of cannabinoid receptors, their signalling and expression at peripheral and central levels in order to understand their implication in neuro-inflammation and review the effects of cannabinoids in neuro-inflammatory disorders. RESULTS Brain inflammatory processes are characterized by infiltration of numerous types of cells: both peripheral and brain resident immune cells and other neuronal cells. The disruption of the blood brain barrier favours cell infiltration in the central nervous system with consequent neuronal damage, a common event in many neuro-inflammatory diseases. Cannabinoids affect brain adaptive and immune response, regulate inflammatory mediators and can exert a role in blood brain barrier damage prevention. CONCLUSION Various patents describe the beneficial properties of cannabinoids in numerous neurodegenerative diseases with inflammatory components and overall effects support the therapeutic application of cannabinoids.

Impact of drought on human health

Over the last few summers in Europe, increasingly hot and dry, we are experiencing a new great problem, the drought, associated with mugginess and insufficient winter and spring rainfall that do not allow the restoration of water reserves. Forecasts for the future are certainly not encouraging at the global level. It is in fact estimated that about half of theworld population by 2025will live in conditions ofwater scarcity, whose quality is definitely lowering in different parts of the world. The greatest impact of drought is on farms and crops, with severe economic repercussions at this time of the year which, on the contrary, should boost the economy. The harmful effects of drought have been well defined and explored in the meteorological, hydrogeological, agricultural and economic context. Less studied is its impact on our health and perhaps we are not adequately prepared to deal with its short and long-term consequences, given the availability of water now taken for granted inWestern and industrialized countries and considered a problem to “Third-World” levels. Climate change that we are now facing, however, seriously undermine this certainty and also themedical community should be prepared to deal with drought-related effects in the daily professional practice, deepening the study of its effects on health and wellbeing. In this context the availability of quality, not contaminated andnot stagnant drinking-water, is an essential prerequisite for the maintenance of adequate levels of sanitation and hygiene in the community and for the containment of transmission and spread of infectious diseases. The direct and indirect consequences of drought on human health obviously depend on both the duration and the severity of drought conditions as well as the economic and social fabric of the country and its availability of resources [1]. Drought-related diseases can be distinguished in: “transmitted by water” (contaminated water) diseases also known as waterborne diseases, which are transmitted through fecal-oral route, including different types of diarrhea and gastroenteritis caused by the bacterium Escherichia coli and other pathogens such as Vibrio cholerae, whose spread is increasing in various geographical areas; “water-based” diseases transmitted by pathogenic species that have life cycles linked to the water, as in the case of schistosomiasis and finally “water-related” diseases, in which not the parasite, but its vector has a cycle involving water. The best known example is malaria, caused by Anopheles mosquitoes whose life cycle occurs mostly in stagnant water. In addition to reducing the amount of available water, the drought worsens the water quality due to an increase of stagnant water where such