Interaction of delta-9-tetrahydrocannabinol with rat B103 neuroblastoma cells

Interaction of Glia Cells with Glioblastoma and Melanoma Cells under the Influence of Phytocannabinoids

Brain tumor heterogeneity and progression are subject to complex interactions between tumor cells and their microenvironment. Glioblastoma and brain metastasis can contain 30–40% of tumor-associated macrophages, microglia, and astrocytes, affecting migration, proliferation, and apoptosis. Here, we analyzed interactions between glial cells and LN229 glioblastoma or A375 melanoma cells in the context of motility and cell–cell interactions in a 3D model. Furthermore, the effects of phytocannabinoids, cannabidiol (CBD), tetrahydrocannabidiol (THC), or their co-application were analyzed. Co-culture of tumor cells with glial cells had little effect on 3D spheroid formation, while treatment with cannabinoids led to significantly larger spheroids. The addition of astrocytes blocked cannabinoid-induced effects. None of the interventions affected cell death. Furthermore, glial cell-conditioned media led to a significant slowdown in collective, but not single-cell migration speed. Taken together, glial cells in glioblastoma and brain metastasis micromilieu impact the tumor spheroid formation, cell spreading, and motility. Since the size of spheroid remained unaffected in glial cell tumor co-cultures, phytocannabinoids increased the size of spheroids without any effects on migration. This aspect might be of relevance since phytocannabinoids are frequently used in tumor therapy for side effects.

On the influence of cannabinoids on cell morphology and motility of glioblastoma cells

The mechanisms behind the anti-tumoral effects of cannabinoids by impacting the migratory activity of tumor cells are only partially understood. Previous studies demonstrated that cannabinoids altered the organization of the actin cytoskeleton in various cell types. As actin is one of the main contributors to cell motility and is postulated to be linked to tumor invasion, we tested the following hypothesizes: 1) Can cannabinoids alter cell motility in a cannabinoid receptor dependent manner? 2) Are these alterations associated with reorganizations in the actin cytoskeleton? 3) If so, what are the underlying molecular mechanisms? Three different glioblastoma cell lines were treated with specific cannabinoid receptor 1 and 2 agonists and antagonists. Afterwards, we measured changes in cell motility using live cell imaging and alterations of the actin structure in fixed cells. Additionally, the protein amount of phosphorylated p44/42 mitogen-activated protein kinase (MAPK), focal adhesion kinases (FAK) and phosphorylated FAK (pFAK) over time were measured. Cannabinoids induced changes in cell motility, morphology and actin organization in a receptor and cell line dependent manner. No significant changes were observed in the analyzed signaling molecules. Cannabinoids can principally induce changes in the actin cytoskeleton and motility of glioblastoma cell lines. Additionally, single cell motility of glioblastoma is independent of their morphology. Furthermore, the observed effects seem to be independent of p44/42 MAPK and pFAK pathways.

The influence of biomechanical properties and cannabinoids on tumor invasion

BACKGROUND

Cannabinoids are known to have an anti-tumorous effect, but the underlying mechanisms are only sparsely understood. Mechanical characteristics of tumor cells represent a promising marker to distinguish between tumor cells and the healthy tissue. We tested the hypothesis whether cannabinoids influence the tumor cell specific mechanical and migratory properties and if these factors are a prognostic marker for the invasiveness of tumor cells.

METHODS

3 different glioblastoma cell lines were treated with cannabinoids and changes of mechanical and migratory properties of single cells were measured using atomic force microscopy and time lapse imaging. The invasiveness of cell lines was determined using a co-culture model with organotypic hippocampal slice cultures.

RESULTS

We found that cannabinoids are capable of influencing migratory and mechanical properties in a cell line specific manner. A network analysis revealed a correlation between a "generalized stiffness" and the invasiveness for all tumor cell lines after 3 and 4 d of invasion time: r3d = -0.88 [-0.52;-0.97]; r4d = -0.90 [-0.59;-0.98].

CONCLUSIONS

Here we could show that a "generalized stiffness" is a profound marker for the invasiveness of a tumor cell population in our model and thus might be of high clinical relevance for drug testing. Additionally cannabinoids were shown to be of potential use for therapeutic approaches of glioblastoma.

Type-1 cannabinoid receptor signaling in neuronal development

The type-1 cannabinoid receptor (CB1R) was initially identified as the neuronal target of Δ(9)-tetrahydrocannabinol (THC), the major psychoactive substance of marijuana. This receptor is one of the most abundant G-protein-coupled receptors in the adult brain, the target of endocannabinoid ligands and a well-characterized retrograde synaptic regulator. However, CB1Rs are also highly and often transiently expressed in neuronal populations in the embryonic and early postnatal brain, even before the formation of synapses. This suggests important physiological roles for CB1Rs during neuronal development. Several recent reviews have summarized our knowledge about the role of the endocannabinoid (eCB) system in neurodevelopment and neurotransmission by focusing on the metabolism of endocannabinoid molecules. Here, we review current knowledge about the effects of the modulation of CB1R signaling during the different phases of brain development. More precisely, we focus on reports that directly implicate CB1Rs during progenitor cell migration and differentiation, neurite outgrowth, axonal pathfinding and synaptogenesis. Based on theoretical considerations and on the reviewed experimental data, we propose a new model to explain the diversity of experimental findings on eCB signaling on neurite growth and axonal pathfinding. In our model, cell-autonomus and paracrine eCBs acting on CB1Rs are part of a global inhibitory network of cytoskeletal effectors, which act in concert with positive-feedback local-excitation loops, to ultimately yield highly polarized neurons.

Impairment of adenylyl cyclase 2 function and expression in hypoxanthine phosphoribosyltransferase-deficient rat B103 neuroblastoma cells as model for Lesch-Nyhan disease: BODIPY-forskolin as pharmacological tool

Hypoxanthine phosphoribosyl transferase (HPRT) deficiency results in Lesch-Nyhan disease (LND). The link between the HPRT defect and the self-injurious behavior in LND is still unknown. HPRT-deficient rat B103 neuroblastoma cells serve as a model system for LND. In B103 cell membranes, HPRT deficiency is associated with a decrease of basal and guanosine triphosphate-stimulated adenylyl cyclase (AC) activity (Pinto and Seifert, J Neurochem 96:454-459, 2006). Since recombinant AC2 possesses a high basal activity, we tested the hypothesis that AC2 function and expression is impaired in HPRT deficiency. We examined AC regulation in B103 cell membranes, cAMP accumulation in intact B103 cells, AC isoform expression, and performed morphological studies. As most important pharmacological tool, we used 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene forskolin (BODIPY-FS) that inhibits recombinant AC2 but activates ACs 1 and 5 (Erdorf et al., Biochem Pharmacol 82:1673-1681, 2011). In B103 control membranes, BODIPY-FS reduced catalysis, but in HPRT(-) membranes, BODIPY-FS was rather stimulatory. 2'(3')-O-(N-methylanthraniloyl) (MANT)-nucleoside 5'-[γ-thio]triphosphates inhibit recombinant ACs 1 and 5 more potently than AC2. In B103 control membranes, MANT-guanosine 5'-[γ-thio]triphosphate inhibited catalysis in control membranes less potently than in HPRT(-) membranes. Quantitative real-time PCR revealed that in HPRT deficiency, AC2 was virtually absent. In contrast, AC5 was up-regulated. Forskolin (FS) and BODIPY-FS induced cell clustering and rounding and neurite extension in B103 cells. The effects of FS and BODIPY-FS were much more prominent in control than in HPRT(-) cells, indicative for a differentiation defect in HPRT deficiency. Neither FS nor BODIPY-FS significantly changed cAMP concentrations in intact B103 cells. Collectively, our data show that HPRT deficiency in B103 cells is associated with impaired AC2 function and expression and reduced sensitivity to differentiation induced by FS and BODIPY-FS. We discuss the pathophysiological implications of our data for LND.

Cannabinoid receptor ligands as potential anticancer agents — high hopes for new therapies?

Objectives

The endocannabinoid system is an endogenous lipid signalling network comprising arachidonic-acid-derived ligands, cannabinoid (CB) receptors, transporters and endocannabinoid degrading enzymes. The CB1 receptor is predominantly expressed in neurons but is also co-expressed with the CB2 receptor in peripheral tissues. In recent years, CB receptor ligands, including Δ9-tetrahydrocannabinol, have been proposed as potential anticancer agents.

Key findings

This review critically discusses the pharmacology of CB receptor activation as a novel therapeutic anticancer strategy in terms of ligand selectivity, tissue specificity and potency. Intriguingly, antitumour effects mediated by cannabinoids are not confined to inhibition of cancer cell proliferation; cannabinoids also reduce angiogenesis, cell migration and metastasis, inhibit carcinogenesis and attenuate inflammatory processes. In the last decade several new selective CB1 and CB2 receptor agents have been described, but most studies in the area of cancer research have used non-selective CB ligands. Moreover, many of these ligands exert prominent CB receptor-independent pharmacological effects, such as activation of the G-protein-coupled receptor GPR55, peroxisome proliferator-activated receptor gamma and the transient receptor potential vanilloid channels.

Summary

The role of the endocannabinoid system in tumourigenesis is still poorly understood and the molecular mechanisms of cannabinoid anticancer action need to be elucidated. The development of CB2-selective anticancer agents could be advantageous in light of the unwanted central effects exerted by CB1 receptor ligands. Probably the most interesting question is whether cannabinoids could be useful in chemoprevention or in combination with established chemotherapeutic agents.

Delta9-Tetrahydrocannabinol inhibits epithelial growth factor-induced lung cancer cell migration in vitro as well as its growth and metastasis in vivo

Delta(9)-Tetrahydrocannabinol (THC) is the primary cannabinoid of marijuana and has been shown to either potentiate or inhibit tumor growth, depending on the type of cancer and its pathogenesis. Little is known about the activity of cannabinoids like THC on epidermal growth factor receptor-overexpressing lung cancers, which are often highly aggressive and resistant to chemotherapy. In this study, we characterized the effects of THC on the EGF-induced growth and metastasis of human non-small cell lung cancer using the cell lines A549 and SW-1573 as in vitro models. We found that these cells express the cannabinoid receptors CB(1) and CB(2), known targets for THC action, and that THC inhibited EGF-induced growth, chemotaxis and chemoinvasion. Moreover, signaling studies indicated that THC may act by inhibiting the EGF-induced phosphorylation of ERK1/2, JNK1/2 and AKT. THC also induced the phosphorylation of focal adhesion kinase at tyrosine 397. Additionally, in in vivo studies in severe combined immunodeficient mice, there was significant inhibition of the subcutaneous tumor growth and lung metastasis of A549 cells in THC-treated animals as compared to vehicle-treated controls. Tumor samples from THC-treated animals revealed antiproliferative and antiangiogenic effects of THC. Our study suggests that cannabinoids like THC should be explored as novel therapeutic molecules in controlling the growth and metastasis of certain lung cancers.

Effects on the immune system

Marijuana and other exogenous cannabinoids alter immune function and decrease host resistance to microbial infections in experimental animal models and in vitro. Two modes of action by which delta9-tetrahydrocannabinol (THC) and other cannabinoids affect immune responses have been proposed. First, cannabinoids may signal through the cannabinoid receptors CB1 and CB2. Second, at sites of direct exposure to high concentrations of cannabinoids, such as the lung, membrane perturbation may be involved. In addition, endogenous cannabinoids or endocannabinoids have been identified and have been proposed as native modulators of immune functions through cannabinoid receptors. Exogenously introduced cannabinoids may disturb this homoeostatic immune balance. A mode by which cannabinoids may affect immune responses and host resistance maybe by perturbing the balance of T helper (Th)1 pro-inflammatory versus Th2 anti-inflammatory cytokines. While marijuana and various cannabinoids have been documented to alter immune functions in vitro and in experimental animals, no controlled longitudinal epidemiological studies have yet definitively correlated immunosuppressive effects with increased incidence of infections or immune disorders in humans. However, cannabinoids by virtue of their immunomodulatory properties have the potential to serve as therapeutic agents for ablation of untoward immune responses.

Tau protein after delta-9-tetrahydrocannabinol in a human neuroblastoma cell line

1. A human neuroblastoma cell line, SH-SY5Y, was used to determine the effects of delta-9-tetrahydrocannabinol (THC) on microtubule-associated tau protein. 2. After 48-hr treatment, THC (10(-9) M) decreased 50 kD tau protein in the cytoplasmic (supernatant) fraction, and in the membrane (pellet) fraction the drug (10(-7) M) also decreased 50 kD tau protein. 3. This reduction in tau protein was accompanied by a 27% reduction (P < 0.05) in the membrane (pellet) total protein after (10(-7) M) THC and a 28% increase (P < 0.02) in cytoplasmic (supernatant) total protein after 10(-9) M THC.

Inhibition of macrophage inducible protein expression by delta-9-tetrahydrocannabinol

Macrophages have been shown to undergo a sequential process to full activation in response to priming and triggering signals such as gamma interferon (IFN gamma) and bacterial lipopolysaccharide (LPS). These cells also may be driven directly to full activation by exposure to relatively high concentrations of LPS. Each of the stages to activation is associated with differential protein expression suggesting that newly synthesized proteins are associated with the functional activities attributable to that activation state. These observations indicate that protein profiles may serve as a barometer of the macrophage activation state. Delta-9-tetrahydrocannabinol (THC), the major psychoactive component in marijuana, was shown to inhibit inducible protein expression in response to the priming agents Concanavalin A (Con A) supernatant and IFN gamma. THC also suppressed protein expression in response to LPS. P388D1 and RAW264.7 macrophage-like cells, treated with Con A supernatant or IFN gamma, exhibited restructuring of protein profiles based on iso-Dalt two-dimensional gel electrophoresis. Protein profile restructuring, distinctive from that elicited in response to priming agents, was seen for macrophages treated with LPS. Treatment of macrophages with Con A supernatant, IFN gamma, or LPS in concert with THC (10(-7) M to 10(-5) M), resulted in the generation of protein profiles whose patterns reverted approximately to those of unprimed or unactivated macrophages. THC was shown to alter the expression of select proteins whose induction is associated with macrophage priming or activation. The expression of P388D1 macrophage class II Ia molecules of the major histocompatibility complex (MHC), in response to Con A supernatant and IFN gamma, was inhibited. THC also altered the expression of tumor necrosis factor alpha (TNF alpha) elicited by RAW264.7 cells in response to LPS. These results suggest that THC alters macrophage functional activities, at least in part, by suppressing their capacity to express effector molecules elicited in response to priming and activating signals.

Influence of marihuana on cellular structures and biochemical activities

Cannabinoids are known to affect a number of cellular systems and functions, but the basis for their action is unclear. In this paper we review the current evidence describing cannabinoid effects on various levels of cellular structure and activity and we present our current studies on the influence of delta-9-tetrahydrocannabinol, cannabidiol and cannabinol on one cellular system, the cytoskeleton. The organization of two cytoskeletal structures, microtubules and microfilaments, were examined and the mRNA levels of tubulin and actin, the major protein components of microtubules and microfilaments, respectively, were analysed.

Chronic marijuana smoke alters alveolar macrophage morphology and protein expression

Male rhesus monkeys were subjected to chronic exposure to marijuana smoke. High dose animals (HI) were exposed 7 days/week to 1 MJ cigarette/day; low dose animals (LO) were exposed on 2 consecutive weekend days to 1 MJ cigarette/day; placebo animals (EM) were exposed to 1 ethanol-extracted MJ cigarette/day for 7 days/week; sham animals (SH) were exposed to sham smoking conditions 7 days/week. This regimen was maintained for 1 year and was followed by a 7 month rest period. Alveolar macrophages of animals exposed to the LO and HI dose smoking regimens exhibited irregular cell surface morphology, increased vacuolization, and a spherical conformation upon adherence to plastic. Gel protein profiles of purified macrophages from HI and LO animals showed marked differences in both constitutive and bacterial lipopolysaccharide-elicited protein expression when compared with those of macrophages from the EM or SH animals. These results indicate that chronic THC exposure alters macrophage morphology and protein expression to external stimuli even after a 7 month rest period.

Specific inhibition of FSH-stimulated cAMP accumulation by delta 9-tetrahydrocannabinol in cultures of rat Sertoli cells

delta 9-Tetrahydrocannabinol (THC), the major psychoactive component in marihuana, is a reproductive toxicant in both man and animals. THC acts at both the level of the pituitary-hypothalamic axis and the testis, specifically the Leydig cell; an effect on the Sertoli cell has not been shown. Since THC inhibits cAMP accumulation in several cell types, we have examined the effect of THC on Sertoli cell function using altered cAMP accumulation as a marker of toxicity. THC reduced the FSH-induced accumulation of cAMP at concentrations which were neither cytotoxic nor affected cellular ATP levels. This inhibition was evident after 3 hr and did not affect the dose of FSH which gave half-maximal stimulation, suggesting that THC does not compete with FSH for binding to its receptor. The ability of THC to inhibit cAMP accumulation was not affected by incubation in the presence of phosphodiesterase inhibitors, making it unlikely that it acts via stimulation of phosphodiesterase activity. This THC-induced inhibition of Sertoli cell cAMP is specific for FSH; it does not affect the ability of forskolin, cholera toxin, isoproterenol, or prostaglandin E1 to stimulate Sertoli cell cAMP. Furthermore, inhibition occurs in the presence of pertussis toxin, suggesting that this effect of THC is independent of the inhibitory adenylate cyclase pathway. Inhibition of Sertoli cell cAMP also occurs with other cannabinoids which are present in marihuana, but which are not psychoactive. These data indicate that a part of the testicular toxicity of THC may be due to a specific alteration of the hormonal control of Sertoli cell function via an inhibition of FSH-stimulated cAMP accumulation.

Delta-9-tetrahydrocannabinol inhibits macrophage protein expression in response to bacterial immunomodulators

The objective of this study was to determine the effect of delta-9-tetrahydrocannabinol (delta-9-THC), the major psychoactive component of marihuana, on macrophage protein expression in response to bacterial immunomodulators. Peritoneal macrophages of (B6C3)F1 mice receiving Propionibacterium acnes exhibited a novel protein profile when compared to resident or vehicle-treated macrophages. In contrast, macrophages from mice treated with P. acnes in concert with delta-9-THC exhibited profiles for which the majority of protein species reverted to patterns seen in profiles of resident or vehicle-treated macrophages. Treatment of the murine macrophage line P388D1 (DBA/2) in vitro with bacterial lipopolysaccharide (LPS) resulted in the hyperproduction of a subset of proteins ranging from 73 to 18 kD relative molecular weight. Coexposure of the P388D1 cells to LPS and 10(-7) M to 10(-5) M delta-9-THC resulted in a dose-related depletion of these proteins. These results suggest that delta-9-THC suppresses the expression of proteins elicited by macrophage bacterial immunomodulators.