Glioblastoma multiforme (GBM) is the most lethal subtype of glioma. Cannabis sativa is used for the treatment of various medical conditions. Around 150 phytocannabinoids have been identified in C. sativa, among them Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) that trigger GBM cell death. However, the optimal combinations of cannabis molecules for anti-GBM activity are unknown. Chemical composition was determined using high-performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC/MS). Cytotoxic activity was determined by XTT and lactate dehydrogenase (LDH) assays and apoptosis and cell cycle by fluorescence-activated cell sorting (FACS). F-actin structures were observed by confocal microscopy, gene expression by quantitative PCR, and cell migration and invasion by scratch and transwell assays, respectively. Fractions of a high-THC cannabis strain extract had significant cytotoxic activity against GBM cell lines and glioma stem cells derived from tumor specimens. A standard mix (SM) of the active fractions F4 and F5 induced apoptosis and expression of endoplasmic reticulum (ER)-stress associated-genes. F4 and F5 inhibited cell migration and invasion, altered cell cytoskeletons, and inhibited colony formation in 2 and 3-dimensional models. Combinations of cannabis compounds exert cytotoxic, anti-proliferative, and anti-migratory effects and should be examined for efficacy on GBM in pre-clinical studies and clinical trials.

Glioblastoma (GBM) is the most common and aggressive primary brain tumor. GBM contains a small subpopulation of glioma stem cells (GSCs) that are implicated in treatment resistance, tumor infiltration, and recurrence, and are thereby considered important therapeutic targets. Recent clinical studies have suggested that the choice of general anesthetic (GA), particularly propofol, during tumor resection, affects subsequent tumor response to treatments and patient prognosis. In this study, we investigated the molecular mechanisms underlying propofol’s anti-tumor effects on GSCs and their interaction with microglia cells. Propofol exerted a dose-dependent inhibitory effect on the self-renewal, expression of mesenchymal markers, and migration of GSCs and sensitized them to both temozolomide (TMZ) and radiation. At higher concentrations, propofol induced a large degree of cell death, as demonstrated using microfluid chip technology. Propofol increased the expression of the lncRNA BDNF-AS, which acts as a tumor suppressor in GBM, and silencing of this lncRNA partially abrogated propofol’s effects. Propofol also inhibited the pro-tumorigenic GSC-microglia crosstalk via extracellular vesicles (EVs) and delivery of BDNF-AS. In conclusion, propofol exerted anti-tumor effects on GSCs, sensitized these cells to radiation and TMZ, and inhibited their pro-tumorigenic interactions with microglia via transfer of BDNF-AS by EVs.

Glioblastoma is one of the most aggressive and lethal forms of brain cancer, with limited therapeutic options and poor patient prognosis. Recent research has identified the TMED family of proteins as key regulators of tumor progression and aggressiveness across multiple cancer types. TMED members are cargo receptors expressed within the early secretory pathway and involved in bidirectional traffic of various proteins including EGFR, TGF-ɑ and WNT. In this study, we explored the therapeutic potential of genetic and pharmacologic inhibition of the cargo receptor TMED9 in glial tumor models. Our findings demonstrate that TMED9 expression is upregulated in glioma and that this upregulation is associated with poor patient survival. Using patient-derived glioma tumor cells, we demonstrate that TMED9 is highly expressed in the cancer stem cell population and that this upregulation promotes the cells’ self-renewal and migration. This is the first time, to the best of our knowledge, that TMED9 has been shown to play a major role in the function and tumorigenesis of brain tumor cancer stem cells. BRD4780, a small molecule that targets TMED9, effectively reduced TMED9 abundance, resulting in decreased viability, migration and stemness of patient-derived glioma stem cells. Moreover, BRD4780 mitigated the proliferation and migration of differentiated glioma tumor cells. When applied together with temozolomide, an established glioblastoma treatment, BRD4780 elicited an enhanced anti-tumor response. Lastly, to demonstrate the broad applicability of our findings, we targeted TMED9 in pediatric glioma cells and showed efficient inhibition of various oncogenic functions. Collectively, our study identifies TMED9 inhibition as a promising therapeutic approach that impairs the tumorigenesis and aggressiveness of brain tumors, with high efficacy against the tumor stem cell population. The effectiveness of TMED9 targeting in different tumor cell populations, the potential of combining this strategy with established therapies and the broad applicability of this approach to multiple cancer types highlight the significance of these findings.