Glioblastomas are highly malignant tumors of the central nervous system that are resistant to radiation and chemotherapy [1]. We explored the role of the phosphatidylinositol (PI) 3-kinase signal transduction pathway in glioblastomas, as this pathway has been shown to inhibit apoptosis induced by cytokine withdrawal and the detachment of cells from the extracellular matrix [2]. Components of this pathway have been implicated in tumor development [3-6]. We show that glioblastoma cells, in contrast to primary human astrocytes, contain high endogenous protein kinase B (PKB/Akt) activity and high levels of PI 3,4,5-triphosphate (PI(3,4,5)P3) and PI(3,4)P2, the lipid products of PI 3-kinase. These glioblastoma cells express mutant forms of the putative 3' phospholipid phosphatase PTEN, also known as MMAC. Expression of wild-type PTEN derived from primary astrocytes, but not of mutant forms of PTEN, reduced the levels of 3' phosphoinositides and inhibited PKB/Akt activity. PTEN antagonized the activation of PKB/Akt by growth factors, by activated PI 3-kinase and by PI-dependent protein kinase-1 (PDK1), but did not antagonize the phospholipid-independent activation of PKB/Akt lacking the pleckstrin homology (PH) domain. These results suggest a role for PTEN in regulating the activity of the PI 3-kinase pathway in malignant human cells.

Glioblastoma (GBM) is the most common form of primary adult brain tumors. A majority of GBMs grow invasively into distant brain tissue, leading to tumor recurrence, which is ultimately incurable. It is, therefore, essential to discover master regulators that control GBM invasiveness and target them therapeutically. We demonstrate here that the transcriptional regulator Id-1 plays a critical role in modulating the invasiveness of GBM cell lines and primary GBM cells. Id-1 expression levels positively correlate with glioma cell invasiveness in culture and with histopathological grades in patient biopsies. Id-1 knockdown dramatically reduces GBM cell invasion that is accompanied by profound morphological changes and robust reduction in expression levels of “mesenchymal” markers, as well as inhibition of self-renewal potential and down-regulation of glioma stem cell markers. Importantly, genetic knockdown of Id-1 leads to a significant increase in survival in an orthotopic model of human GBM. Furthermore, we show that a non-toxic compound, cannabidiol, significantly down-regulates Id-1 gene expression and associated glioma cell invasiveness and self-renewal. Additionally, cannabidiol significantly inhibits the invasion of GBM cells through an organotypic brain slice and glioma progression in vivo. Our results suggest that Id-1 regulates multiple tumor-promoting pathways in GBM, and that drugs targeting Id-1 represent a novel and promising strategy for improving the therapy and outcome of GBM patients.

The cannabinoid 1 (CB 1 ) and cannabinoid 2 (CB 2 ) receptor agonist Δ 9 -tetrahydrocannabinol (THC) has been shown to be a broad-range inhibitor of cancer in culture and in vivo, and is currently being used in a clinical trial for the treatment of glioblastoma. It has been suggested that other plant-derived cannabinoids, which do not interact efficiently with CB 1 and CB 2 receptors, can modulate the actions of Δ 9 -THC. There are conflicting reports, however, as to what extent other cannabinoids can modulate Δ 9 -THC activity, and most importantly, it is not clear whether other cannabinoid compounds can either potentiate or inhibit the actions of Δ 9-THC. We therefore tested cannabidiol, the second most abundant plant-derived cannabinoid, in combination with Δ 9 -THC. In the U251 and SF126 glioblastoma cell lines, Δ 9 -THC and cannabidiol acted synergistically to inhibit cell proliferation. The treatment of glioblastoma cells with both compounds led to significant modulations of the cell cycle and induction of reactive oxygen species and apoptosis as well as specific modulations of extracellular signal-regulated kinase and caspase activities. These specific changes were not observed with either compound individually, indicating that the signal transduction pathways affected by the combination treatment were unique. Our results suggest that the addition of cannabidiol to Δ 9 -THC may improve the overall effectiveness of Δ 9 -THC in the treatment of glioblastoma in cancer patients.

This study examined the changes in cortisol levels and psychological distress symptoms of 83 nonclinical subjects receiving a single hour long intervention. Subjects were randomly assigned to either an emotional freedom technique (EFT) group, a psychotherapy group receiving a supportive interviews (SI), or a no treatment (NT) group. Salivary cortisol assays were performed immediately before and 30 minutes after the intervention. Psychological distress symptoms were assessed using the symptom assessment-45. The EFT group showed statistically significant improvements in anxiety (-58.34%, p < 0.05), depression (-49.33%, p < 0.002), the overall severity of symptoms (-50.5%, p < 0.001), and symptom breadth (-41.93%, p < 0.001). The EFT group experienced a significant decrease in cortisol level (-24.39%; SE, 2.62) compared with the decrease observed in the SI (-14.25%; SE, 2.61) and NT (-14.44%; SE, 2.67) groups (p < 0.03). The decrease in cortisol levels in the EFT group mirrored the observed improvement in psychological distress.