Cannabinoids as Modulators of Cell Death: Clinical Applications and Future Directions

The antitumor action of endocannabinoids in the tumor microenvironment of glioblastoma

Approximately 80% of all malignant brain tumors are gliomas, which are primary brain tumors. The most prevalent subtype of glioma, glioblastoma multiforme (GBM), is also the most deadly. Chemotherapy, immunotherapy, surgery, and conventional pharmacotherapy are currently available therapeutic options for GBM; unfortunately, these approaches only prolong the patient's life by 5 years at most. Despite numerous intensive therapeutic options, GBM is considered incurable. Accumulating preclinical data indicate that overt antitumoral effects can be induced by pharmacologically activating endocannabinoid receptors on glioma cells by modifying important intracellular signaling cascades. The complex mechanism underlying the endocannabinoid receptor-evoked antitumoral activity in experimental models of glioma may inhibit the ability of cancer cells to invade, proliferate, and exhibit stem cell-like characteristics, along with altering other aspects of the complex tumor microenvironment. The exact biological function of the endocannabinoid system in the development and spread of gliomas, however, is remains unclear and appears to rely heavily on context. Previous studies have revealed that endocannabinoid receptors are present in the tumor microenvironment, suggesting that these receptors could be novel targets for the treatment of GBM. Additionally, endocannabinoids have demonstrated anticancer effects through signaling pathways linked to the classic features of cancer. Thus, the pharmacology of endocannabinoids in the glioblastoma microenvironment is the main topic of this review, which may promote the development of future GBM therapies.

Targeting the Endocannabinoid System Present in the Glioblastoma Tumour Microenvironment as a Potential Anti-Cancer Strategy

The highly aggressive and invasive glioblastoma (GBM) tumour is the most malignant lesion among adult-type diffuse gliomas, representing the most common primary brain tumour in the neuro-oncology practice of adults. With a poor overall prognosis and strong resistance to treatment, this nervous system tumour requires new innovative treatment. GBM is a polymorphic tumour consisting of an array of stromal cells and various malignant cells contributing to tumour initiation, progression, and treatment response. Cannabinoids possess anti-cancer potencies against glioma cell lines and in animal models. To improve existing treatment, cannabinoids as functionalised ligands on nanocarriers were investigated as potential anti-cancer agents. The GBM tumour microenvironment is a multifaceted system consisting of resident or recruited immune cells, extracellular matrix components, tissue-resident cells, and soluble factors. The immune microenvironment accounts for a substantial volume of GBM tumours. The barriers to the treatment of glioblastoma with cannabinoids, such as crossing the blood-brain barrier and psychoactive and off-target side effects, can be alleviated with the use of nanocarrier drug delivery systems and functionalised ligands for improved specificity and targeting of pharmacological receptors and anti-cancer signalling pathways. This review has shown the presence of endocannabinoid receptors in the tumour microenvironment, which can be used as a potential unique target for specific drug delivery. Existing cannabinoid agents, studied previously, show anti-cancer potencies via signalling pathways associated with the hallmarks of cancer. The results of the review can be used to provide guidance in the design of future drug therapy for glioblastoma tumours.

Discovery of Potent and Selective CB2 Agonists Utilizing a Function-Based Computational Screening Protocol

Nowadays, the identification of agonists and antagonists represents a great challenge in computer-aided drug design. In this work, we developed a computational protocol enabling us to design/screen novel chemicals that are likely to serve as selective CB2 agonists. The principle of this protocol is that by calculating the ligand-residue interaction profile (LRIP) of a ligand binding to a specific target, the agonist-antagonist function of a compound is then able to be determined after statistical analysis and free energy calculations. This computational protocol was successfully applied in CB2 agonist development starting from a lead compound, and a success rate of 70% was achieved. The functions of the synthesized derivatives were determined by in vitro functional assays. Moreover, the identified potent CB2 agonists and antagonists strongly interact with the key residues identified using the already known potent CB2 agonists/antagonists. The analysis of the interaction profile of compound 6, a potent agonist, showed strong interactions with F2.61, I186, and F2.64, while compound 39, a potent antagonist, showed strong interactions with L17, W6.48, V6.51, and C7.42. Still, some residues including V3.32, T3.33, S7.39, F183, W5.43, and I3.29 are hotspots for both CB2 agonists and antagonists. More significantly, we identified three hotspot residues in the loop, including I186 for agonists, L17 for antagonists, and F183 for both. These hotspot residues are typically not considered in CB1/CB2 rational ligand design. In conclusion, LRIP is a useful concept in rationally designing a compound to possess a certain function.

Validating the anti-lymphoma pharmacodynamic actions of the endocannabinoids on canine non-Hodgkin lymphoma

AIMS

This study established the in vitro anti-lymphoma pharmacodynamic actions of the endocannabinoids (anandamide-AEA and 2-arachidonoylglycerol-2AG) on canine non-Hodgkin lymphoma (NHL) and human NHL cells.

MAIN METHODS

The expression of cannabinoid (CB₁ and CB₂) receptors in various canine NHL cells {1771, CLBL-1, CLL-1, peripheral blood mononuclear cells (PBMCs)} was studied using Quantitative real-time PCR (RT-qPCR). Anti-lymphoma cell viability assay was performed to assess the effect of endocannabinoids on various canine and human NHL cells (1771, CLBL-1, CLL-1, Ramos cells). The spectrophotometric and fluorometric procedures evaluated oxidative stress, inflammation, apoptosis, and mitochondrial function markers. SAS® and Prism-V La Jolla, CA, USA, were used for statistical analysis.

KEY FINDINGS

The current study validated the presence of CB₁ and CB₂ receptors in the canine NHL cells. There was a significantly higher expression of CB₁ and CB₂ receptors in B-cell lymphoma (BCL) cells (1771, CLBL-1, Ramos) compared to canine T-cell lymphoma (TCL) cells (CL-1). AEA and 2AG dose and time-dependently exhibited significant but differential anti-lymphoma effects on canine and human NHL cells. Anti-lymphoma pharmacodynamic actions of the endocannabinoids in the canine 1771 NHL cells revealed a significant alteration in the markers of oxidative stress, inflammation, and a decrease in mitochondrial function without altering the apoptotic markers.

SIGNIFICANCE

Establishing the anti-lymphoma pharmacodynamic actions of endocannabinoids may provide new therapeutic interventions and expedite cannabinoid research.

Cannabinoid and Opioid Receptor Affinity and Modulation of Cancer-Related Signaling Pathways of Machaeriols and Machaeridiols from Machaerium Pers

Machaeriols and machaeridiols are unique hexahydrodibenzopyran-type aralkyl phytocannabinoids isolated from Machaerium Pers. Earlier studies of machaeriol A (1) and B (2) did not show any affinity for cannabinoid receptor 1 (CB1 or CNR1), although they are structural analogs of psychoactive hexahydrocannabinol. This study comprehensively reports on the affinities of isolated Machaerium Pers. compounds, namely machaeriol A-D (1-4) and machaeridiol A-C (5-7), against cannabinoid (CB1 and CB2) and opioid (κ, δ and µ) receptors. Among the isolated compounds, machaeriol D (4) and machaeridiol A-C (5-7) showed some selective binding affinity for the CB2 receptor, using a radioligand binding assay, with K_i values of >1.3, >1.77, >2.18 and >1.1 μM, respectively. On the other hand, none of the compounds showed any binding to the CB1 receptor. Due to recent reports on the anticancer potential of the endocannabinoid system, compounds 1-7 were tested against a battery of luciferase reporter gene vectors that assess the activity of many cancer-related signaling pathways, including Stat3, Smad2/3, AP-1, NF-κB, E2F, Myc, Ets, Notch, FoxO, Wnt, Hedgehog and pTK in HeLa and T98G glioblastoma cells. Complete dose-response curves have been determined for each compound in both of these cell lines, which revealed that machaeridiol 6 displayed activities (IC₅₀ in µM in HeLa and T98G cells) towards Stat3 (4.7, 1.4), Smad2/3 (1.2, 3.0), AP-1 (5.9, 4.2), NF-κB (0.5, 4.0), E2F (5.7, 0.7), Myc (5.3, 2.0), ETS (inactive, 5.9), Notch (5.3, 4.6), Wnt (4.2, inactive) and Hedgehog (inactive, 5.0). Furthermore, a combination study between machaeriol C (3) and machaeridiol B (6) displayed additive effects for E2F, ETS, Wnt and Hedgehog pathways, where these compounds individually were either minimally active or inactive. None of the compounds inhibited luciferase expression driven by the minimal thymidine kinase promoter (pTK), indicating the lack of general cytotoxicity for luciferase enzyme inhibition at the 50 µM concentration in both of these cell lines. The significance of the inhibition of these signaling pathways via machaeridiol 5-7 and their cross-talk potential has been discussed.

The Role of Cannabinoids in CNS Development: Focus on Proliferation and Cell Death

The active principles of Cannabis sativa are potential treatments for several diseases, such as pain, seizures and anorexia. With the increase in the use of cannabis for medicinal purposes, a more careful assessment of the possible impacts on embryonic development becomes necessary. Surveys indicate that approximately 3.9% of pregnant women use cannabis in a recreational and/or medicinal manner. However, although the literature has already described the presence of endocannabinoid system components since the early stages of CNS development, many of their physiological effects during this stage have not yet been established. Moreover, it is still uncertain how the endocannabinoid system can be altered in terms of cell proliferation and cell fate, neural migration, neural differentiation, synaptogenesis and particularly cell death. In relation to cell death in the CNS, knowledge about the effects of cannabinoids is scarce. Thus, the present work aims to review the role of the endocannabinoid system in different aspects of CNS development and discuss possible side effects or even opportunities for treating some conditions in the development of this tissue.

Cannabinoids in Breast Cancer: Differential Susceptibility According to Subtype

Although cannabinoids have been used for centuries for diverse pathological conditions, recently, their clinical interest and application have emerged due to their diverse pharmacological properties. Indeed, it is well established that cannabinoids exert important actions on multiple sclerosis, epilepsy and pain relief. Regarding cancer, cannabinoids were first introduced to manage chemotherapy-related side effects, though several studies demonstrated that they could modulate the proliferation and death of different cancer cells, as well as angiogenesis, making them attractive agents for cancer treatment. In relation to breast cancer, it has been suggested that estrogen receptor-negative (ER-) cells are more sensitive to cannabinoids than estrogen receptor-positive (ER+) cells. In fact, most of the studies regarding their effects on breast tumors have been conducted on triple-negative breast cancer (TNBC). Nonetheless, the number of studies on human epidermal growth factor receptor 2-positive (HER2+) and ER+ breast tumors has been rising in recent years. However, besides the optimistic results obtained thus far, there is still a long way to go to fully understand the role of these molecules. This review intends to help clarify the clinical potential of cannabinoids for each breast cancer subtype.

Endocannabinoid System and Tumour Microenvironment: New Intertwined Connections for Anticancer Approaches

The tumour microenvironment (TME) is now recognised as a hallmark of cancer, since tumour:stroma crosstalk supports the key steps of tumour growth and progression. The dynamic co-evolution of the tumour and stromal compartments may alter the surrounding microenvironment, including the composition in metabolites and signalling mediators. A growing number of evidence reports the involvement of the endocannabinoid system (ECS) in cancer. ECS is composed by a complex network of ligands, receptors, and enzymes, which act in synergy and contribute to several physiological but also pathological processes. Several in vitro and in vivo evidence show that ECS deregulation in cancer cells affects proliferation, migration, invasion, apoptosis, and metastatic potential. Although it is still an evolving research, recent experimental evidence also suggests that ECS can modulate the functional behaviour of several components of the TME, above all the immune cells, endothelial cells and stromal components. However, the role of ECS in the tumour:stroma interplay remains unclear and research in this area is particularly intriguing. This review aims to shed light on the latest relevant findings of the tumour response to ECS modulation, encouraging a more in-depth analysis in this field. Novel discoveries could be promising for novel anti-tumour approaches, targeting the microenvironmental components and the supportive tumour:stroma crosstalk, thereby hindering tumour development.

Knowledge and attitudes of Italian medical oncologists and palliative care physicians toward medical use of cannabis in cancer care: a national survey

PURPOSE

Despite advances in supportive care, cancer-related symptoms tend to be persistent regardless of cancer type, stage of disease, or treatment received. There is an increasing prescription for complementary and alternative medicines, such as medical cannabis (MC). Knowledge and attitudes of Italian medical oncologists and palliative care physicians toward medical cannabis in cancer care remain unknown.

METHODS

We conducted a cross-sectional study to investigate the knowledge and attitude toward MC prescription among cancer care professionals in Italy. All invited participants received an email with the electronic questionnaire accessible through a direct link.

RESULTS

Among the 2616 members who received the invitation, 475 replied to the questionnaire and were considered for the survey analysis. The most prescribed formulations among those available in Italy were cannabis FM2. The most frequent clinical indications for the use of MC were pain, gastrointestinal, and mood disorders. Only 9 responders reported MC-related side effects like anxiety insomnia and muscle spasms. The question regarding the normative references for MC prescription and use in Italy had conflicting results: only 14% indicated the exact legislative reference.

CONCLUSION

Our study highlights a significant discrepancy between personal attitudes, prescription levels, and actual knowledge on MC. This represent a critical issue that should be systemically faced, building educational programs and national guidelines that sublimate personal physicians' beliefs and predispositions, resulting in a robust science-based MC practice. Only through coordinated interventions on science and health policy of MC, there will be success of safety and efficacy, ensuring the best knowledge for the best outcomes.

Unveiling the mechanism of action behind the anti-cancer properties of cannabinoids in ER+ breast cancer cells: Impact on aromatase and steroid receptors

Breast cancer is the leading cause of cancer-related death in women worldwide. In the last years, cannabinoids have gained attention in the clinical setting and clinical trials with cannabinoid-based preparations are underway. However, contradictory anti-tumour properties have also been reported. Thus, the elucidation of the molecular mechanisms behind their anti-tumour efficacy is crucial to better understand its therapeutic potential. Considering this, our work aims to clarify the molecular mechanisms underlying the anti-cancer properties of the endocannabinoid anandamide (AEA) and of the phytocannabinoids, cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC), in estrogen receptor-positive (ER⁺) breast cancer cells that overexpress aromatase (MCF-7aro). Their in vitro effects on cell proliferation, cell death and activity/expression of aromatase, ERα, ERβ and AR were investigated. Our results demonstrated that cannabinoids disrupted MCF-7aro cell cycle progression. Unlike AEA and THC that induced apoptosis, CBD triggered autophagy to promote apoptotic cell death. Interestingly, all cannabinoids reduced aromatase and ERα expression levels in cells. On the other hand, AEA and CBD not only exhibited high anti-aromatase activity but also induced up-regulation of ERβ. Therefore, all cannabinoids, albeit by different actions, target aromatase and ERs, impairing, in that way, the growth of ER⁺ breast cancer cells, which is dependent on estrogen signalling. As aromatase and ERs are key targets for ER⁺ breast cancer treatment, cannabinoids can be considered as potential and attractive therapeutic compounds for this type of cancer, being CBD the most promising one. Thus, from an in vitro perspective, this work may contribute to the growing mass of evidence of cannabinoids and cannabinoids-based medicines as potential anti-cancer drugs.

Exposure to drugs of abuse induce effects that persist across generations

Substance use disorders are highly prevalent and continue to be one of the leading causes of disability in the world. Notably, not all people who use addictive drugs develop a substance use disorder. Although substance use disorders are highly heritable, patterns of inheritance cannot be explained purely by Mendelian genetic mechanisms. Vulnerability to developing drug addiction depends on the interplay between genetics and environment. Additionally, evidence from the past decade has pointed to the role of epigenetic inheritance in drug addiction. This emerging field focuses on how environmental perturbations, including exposure to addictive drugs, induce epigenetic modifications that are transmitted to the embryo at fertilization and modify developmental gene expression programs to ultimately impact subsequent generations. This chapter highlights intergenerational and transgenerational phenotypes in offspring following a history of parental drug exposure. Special attention is paid to parental preconception exposure studies of five drugs of abuse (alcohol, cocaine, nicotine, cannabinoids, and opiates) and associated behavioral and physiological outcomes in offspring. The highlighted studies demonstrate that parental exposure to drugs of abuse has enduring effects that persist into subsequent generations. Understanding the contribution of epigenetic inheritance in drug addiction may provide clues for better treatments and therapies for substance use disorders.

Cannabinoid CP55940 selectively induces apoptosis in Jurkat cells and in ex vivo T-cell acute lymphoblastic leukemia through H2O2 signaling mechanism

T-cell acute lymphoblastic leukemia (T-ALL) is a highly heterogeneous malignant hematological disorder arising from T-cell progenitors. This study was aimed to evaluate the cytotoxic effect of CP55940 on human peripheral blood lymphocytes (PBL) and on T-ALL cells (Jurkat). PBL and Jurkat cells were treated with CP55940 (0-20 μM), and morphological changes in the cell nucleus/ DNA, mitochondrial membrane potential (ΔΨm), and intracellular reactive oxygen species levels were determined by fluorescence microscopy and flow cytometry. Cellular apoptosis markers were also evaluated by western blotting, pharmacological inhibition and immunofluorescence. CP55940 induced apoptotic cell death in Jurkat cells, but not in PBL, in a dose-response manner with increasing fragmentation of DNA, arrest of cell cycle and damage of ΔΨm. CP55940 increased dichlorofluorescein fluorescence (DCF) intensity, increased DJ-1 Cys¹⁰⁶- sulfonate, a marker of intracellular stress, induced the up-regulation of p53 and phosphorylation of transcription factor c-JUN. It increased the expression of BAX and PUMA, up-regulated mitochondrial proteins PINK1 and Parkin, and activated CASPASE-3. Antioxidant NAC, pifithrin-α, and SP600125 blocked CP55940 deleterious effect on Jurkat cells. However, the potent and highly specific cannabinoid CB1 and CB2 receptor inverse agonist SR141716 and SR144528 were unable to blunt CP55940-induced apoptosis in Jurkat cells. Conclusively CP55940 provokes cell death in Jurkat through CBR-independent mechanism. Interestingly, CP55940 was also cytotoxic to ex vivo T-ALL cells from chemotherapy-resistant pediatric patients. In conclusion, CP55940 selectively induces apoptosis in Jurkat cells through a H₂O₂-mediated signaling pathway. Our findings support the use of cannabinoids as a potential treatment for T-ALL cells.

Allosteric modulators targeting cannabinoid cb1 and cb2 receptors: implications for drug discovery

Allosteric modulators of cannabinoid receptors hold great therapeutic potential, as they do not possess intrinsic efficacy, but instead enhance or diminish the receptor's response of orthosteric ligands allowing for the tempering of cannabinoid receptor signaling without the desensitization, tolerance and dependence. Allosteric modulators of cannabinoid receptors have numerous advantages over the orthosteric ligands such as higher receptor type selectivity, probe dependence and biased signaling, so they have a great potential to separate the therapeutic benefits from side effects own of orthosteric ligands. This review aims to give an overview of the CB1 and CB2 receptor allosteric modulators highlighting the structure-activity relationship and pharmacological profile of each classes, and their future promise.

Cannabinoids as anticancer therapeutic agents

The recent announcement of marijuana legalization in Canada spiked many discussions about potential health benefits of Cannabis sativa. Cannabinoids are active chemical compounds produced by cannabis, and their numerous effects on the human body are primarily exerted through interactions with cannabinoid receptor types 1 (CB1) and 2 (CB2). Cannabinoids are broadly classified as endo-, phyto-, and synthetic cannabinoids. In this review, we will describe the activity of cannabinoids on the cellular level, comprehensively summarize the activity of all groups of cannabinoids on various cancers and propose several potential mechanisms of action of cannabinoids on cancer cells.

Cannabis sativa: Much more beyond Δ9-tetrahydrocannabinol

Cannabis is the most used illicit drug worldwide and its medicinal use is under discussion, being regulated in several countries. However, the psychotropic effects of Δ⁹-tetrahydrocannabinol (THC), the main psychoactive compound of Cannabis sativa, are of concern. Thus, the interest in the isolated constituents without psychotropic activity, such as cannabidiol (CBD) and cannabidivarin (CBDV) is growing. CBD and CBDV are lipophilic molecules with poor oral bioavailability and are mainly metabolized by cytochrome P450 (CYP450) enzymes. The pharmacodynamics of CBD is the best explored, being able to interact with diverse molecular targets, like cannabinoid receptors, G protein-coupled receptor-55, transient receptor potential vanilloid 1 channel and peroxisome proliferator-activated receptor-γ. Considering the therapeutic potential, several clinical trials are underway to study the efficacy of CBD and CBDV in different pathologies, such as neurodegenerative diseases, epilepsy, autism spectrum disorders and pain conditions. The anti-cancer properties of CBD have also been demonstrated by several pre-clinical studies in different types of tumour cells. Although less studied, CBDV, a structural analogue of CBD, is receiving attention in the last years. CBDV exhibits anticonvulsant properties and, currently, clinical trials are underway for the treatment of autism spectrum disorders. Despite the benefits of these phytocannabinoids, it is important to highlight their potential interference with relevant physiologic mechanisms. In fact, CBD interactions with CYP450 enzymes and with drug efflux transporters may have serious consequences when co-administered with other drugs. This review summarizes the therapeutic advances of CBD and CBDV and explores some aspects of their pharmacokinetics, pharmacodynamics and possible interactions. Moreover, it also highlights the therapeutic potential of CBD and CBDV in several medical conditions and clinical applications.

The Endocannabinoid System: A Target for Cancer Treatment

In recent years, the endocannabinoid system has received great interest as a potential therapeutic target in numerous pathological conditions. Cannabinoids have shown an anticancer potential by modulating several pathways involved in cell growth, differentiation, migration, and angiogenesis. However, the therapeutic efficacy of cannabinoids is limited to the treatment of chemotherapy-induced symptoms or cancer pain, but their use as anticancer drugs in chemotherapeutic protocols requires further investigation. In this paper, we reviewed the role of cannabinoids in the modulation of signaling mechanisms implicated in tumor progression.

Efficacy of Cannabinoids in a Pre-Clinical Drug-Screening Platform for Alzheimer's Disease

Finding a therapy for Alzheimer's disease (AD) is perhaps the greatest challenge for modern medicine. The chemical scaffolds of many drugs in the clinic today are based upon natural products from plants, yet Cannabis has not been extensively examined as a source of potential AD drug candidates. Here, we determine if a number of non-psychoactive cannabinoids are neuroprotective in a novel pre-clinical AD and neurodegeneration drug-screening platform that is based upon toxicities associated with the aging brain. This drug discovery paradigm has yielded several compounds in or approaching clinical trials for AD. Eleven cannabinoids were assayed for neuroprotection in assays that recapitulate proteotoxicity, loss of trophic support, oxidative stress, energy loss, and inflammation. These compounds were also assayed for their ability to remove intraneuronal amyloid and subjected to a structure-activity relationship analysis. Pairwise combinations were assayed for their ability to synergize to produce neuroprotective effects that were greater than additive. Nine of the 11 cannabinoids have the ability to protect cells in four distinct phenotypic neurodegeneration screening assays, including those using neurons that lack CB1 and CB2 receptors. They are able to remove intraneuronal Aβ, reduce oxidative damage, and protect from the loss of energy or trophic support. Structure-activity relationship (SAR) data show that functional antioxidant groups such as aromatic hydroxyls are necessary but not sufficient for neuroprotection. Therefore, there is a need to focus upon CB1 agonists that have these functionalities if neuroprotection is the goal. Pairwise combinations of THC and CBN lead to a synergistic neuroprotective interaction. Together, these results significantly extend the published data by showing that non-psychoactive cannabinoids are potential lead drug candidates for AD and other neurodegenerative diseases.

The role of lipid signaling in the progression of malignant melanoma

In the past decades, a vast amount of data accumulated on the role of lipid signaling pathways in the progression of malignant melanoma, the most metastatic/aggressive human cancer type. Genomic studies identified that PTEN loss is the leading factor behind the activation of the PI3K-signaling pathway in melanoma, mutations of which are one of the main resistance mechanisms behind target therapy failures. On the other hand, illegitimate expressions of megakaryocytic genes p12-lipoxyganse, cyclooxygenase-2, and phosphodiestherase-2/autotaxin (ATX) are mostly involved in the regulation of motility signaling in melanoma through various G-protein-coupled bioactive lipid receptors. Furthermore, endocannabinoid signaling can also be a novel paracrine survival factor in melanoma. Last but not least, prenylation inhibitors acting even on mutated small GTP-ases, such as NRAS of melanoma may offer novel therapeutic opportunities. As regards melanoma, the most effective therapy nowadays is immunotherapy, with the resistance mechanisms also possibly involving the lipid signaling activities of melanoma cells, which further supports the idea of their being therapeutic targets.

Anti-tumoral potential of MDA19 in human osteosarcoma via suppressing PI3K/Akt/mTOR signaling pathway

Osteosarcoma (OS) is the most common primary malignancy of skeleton with higher mortality rates amongst children and young adults worldwide, whereas effective and secure therapies have also been sought by researches with ongoing efforts. The purpose of the present study was to investigate the impact of N′-[(3Z)-1-(1-hexyl)-2-oxo-1,2-dihydro-3H-indol-3-ylidene] benzohydrazide (MDA19) on OS and explore its potential mechanism. Cell Counting Kit-8 (CCK8) and colony formation assay were employed to evaluate the potential effect of MDA19 on U2OS and MG-63 cells proliferation. Moreover, transwell migration and invasion assay were performed to assess the influence of MDA19 on U2OS and MG-63 cells migration and invasion. In addition, Annexin V-FITC/propidium iodide (Annexin V-FITC/PI) staining and flow cytometry were used to examine apoptotic ratio of the U2OS and MG-63 cells. Meanwhile, Western blot analysis was applied to explore change of relevant mechanism proteins in OS cells treated with MDA19. Our study showed that MDA19 had anti-proliferative activity of OS cells in a dose- and time-dependent manner, simultaneously, inhibition of colony formation was also observed in U2OS and MG-63 cells after incubation of MDA19. Besides, MDA19 could significantly inhibit the number of migrated and invaded OS cells and markedly increase the OS cells apoptosis rate. Mechanistically, we detected detectable reductions in apoptosis related proteins, epithelial–mesenchymal transition (EMT)-related proteins and activity of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling in U2OS and MG-63 cells exposure to MDA19. Overall, the current study indicates in vitro anti-proliferative, anti-metastatic, and pro-apoptotic potential of MDA19 in U2OS and MG-63 cells. Our findings propose a clue for further studies with this compound in preclinical and clinical treatment for OS.

Identification of the First Synthetic Allosteric Modulator of the CB2 Receptors and Evidence of Its Efficacy for Neuropathic Pain Relief

The direct activation of cannabinoid receptors (CBRs) results in several beneficial effects; therefore several CBRs ligands have been synthesized and tested in vitro and in vivo. However, none of them reached an advanced phase of clinical development due mainly to side effects on the CNS. Medicinal chemistry approaches are now engaged to develop allosteric modulators that might offer a novel therapeutic approach to achieve potential therapeutic benefits avoiding inherent side effects of orthosteric ligands. Here we identify the first ever synthesized positive allosteric modulator (PAM) that targets CB₂Rs. The evidence for this was obtained using [³H]CP55940 and [³⁵S]GTPγS binding assays. This finding will be useful for the characterization of allosteric binding site(s) on CB₂Rs which will be essential for the further development of CB₂R allosteric modulators. Moreover, the new CB₂R PAM displayed antinociceptive activity in vivo in an experimental mouse model of neuropathic pain, raising the possibility that it might be a good candidate for clinical development.

Fatty acids and related lipid mediators in the regulation of cutaneous inflammation

Human skin has a distinct profile of fatty acids and related bioactive lipid mediators that regulate many aspects of epidermal and dermal homeostasis, including immune and inflammatory reactions. Sebum lipids act as effective antimicrobial agents, shape immune cell communications and contribute to the epidermal lipidome. The essential fatty acid linoleic acid is crucial for the structure of the epidermal barrier, while polyunsaturated fatty acids act as precursors to eicosanoids, octadecanoids and docosanoids through cyclooxygenase, lipoxygenase and cytochrome P450 monooxygenase-mediated reactions, and endocannabinoids and N-acyl ethanolamines. Cross-communication between these families of bioactive lipids suggests that their cutaneous activities should be considered as part of a wider metabolic network that can be targeted to maintain skin health, control inflammation and improve skin pathologies.

Synergistic interaction of the cannabinoid and death receptor systems - a potential target for future cancer therapies?

Cannabinoid receptors have been shown to interact with other receptors, including tumor necrosis factor receptor superfamily (TNFRS) members, to induce cancer cell death. When cannabinoids and death-inducing ligands (including TNF-related apoptosis-inducing ligand) are administered together, they have been shown to synergize and demonstrate enhanced antitumor activity in vitro. Certain cannabinoid ligands have been shown to sensitize cancer cells and synergistically interact with members of the TNFRS, thus suggesting that the combination of cannabinoids with death receptor (DR) ligands induces additive or synergistic tumor cell death. This review summarizes recent findings on the interaction of the cannabinoid and DR systems and suggests possible clinical co-application of cannabinoids and DR ligands in the treatment of various malignancies.