Cannabidiol stimulates AML-1a-dependent glial differentiation and inhibits glioma stem-like cells proliferation by inducing autophagy in a TRPV2-dependent manner

Glioma stem-like cells (GSCs) correspond to a tumor cell subpopulation, involved in glioblastoma multiforme (GBM) tumor ini- tiation and acquired chemoresistance. Currently, drug-induced differentiation is considered as a promising approach to eradi- cate this tumor-driving cell population. Recently, the effect of cannabinoids (CBs) in promoting glial differentiation and inhibiting gliomagenesis has been evidenced. Herein, we demonstrated that cannabidiol (CBD) by activating transient receptor potential vanilloid-2 (TRPV2) triggers GSCs differentiation activating the autophagic process and inhibits GSCs proliferation and clonogenic capability. Above all, CBD and carmustine (BCNU) in combination overcome the high resistance of GSCs to BCNU treatment, by inducing apoptotic cell death. Acute myeloid leukemia (Aml-1) transcription factors play a pivotal role in GBM proliferation and differentiation and it is known that Aml-1 control the expression of several nociceptive receptors. So, we evaluated the expression levels of Aml-1 spliced variants (Aml-1a, b and c) in GSCs and during their differentiation. We found that Aml-1a is upregulated during GSCs differentiation, and its downregulation restores a stem cell phenotype in differ- entiated GSCs. Since it was demonstrated that CBD induces also TRPV2 expression and that TRPV2 is involved in GSCs differ- entiation, we evaluated if Aml-1a interacted directly with TRPV2 promoters. Herein, we found that Aml-1a binds TRPV2 promoters and that Aml-1a expression is upregulated by CBD treatment, in a TRPV2 and PI3K/AKT dependent manner. Alto- gether, these results support a novel mechanism by which CBD inducing TRPV2-dependent autophagic process stimulates Aml-1a-dependent GSCs differentiation, abrogating the BCNU chemoresistance in GSCs

Advances in transient receptor potential vanilloid-2 channel expression and function in tumor growth and progression.

Aim of this review is to study the role of the TRPV2 channel, a member of the TRPV subfamily of TRP channels, in tumor progression. Physiologically, the triggering of TRPV2 by agonists/activators (e.g., growth factors, hormones and cannabinoids), by inducing TRPV2 translocation from the endosome to the plasmatic membrane, inhibit cell proliferation and induce necrosis and/or apoptosis. Thus, loss or alterations of TRPV2 proliferative and apoptotic signals, results in uncontrolled proliferation and augmented resistance to apoptotic stimuli. For example in prostate cancer cells, the TRPV2 activation following lysophospholipid or adrenomedullin stimulation enhances the invasiveness of cancer cells; furthermore, the increased malignancy of castration-resistant prostate cancer cells was associated with enhanced TRPV2 expression, mainly in metastatic prostate cancer cells. In addition, the TRPV2 cellular functions may also to be related to the presence of TRPV2 variants, able to interfere with the physiological functions of normal TRPV2 channels. In this regard, bladder cancer tumors show loss or reduction of a short TRPV2 variant during cancer progression, with increased malignancy and invasiveness. High expression of TRPV2 was also observed more frequently in esophageal squamous cell carcinoma patients with advanced pT stage, lymph node metastasis and advanced pathological stage

Cross-talk between microRNAs, long non-coding RNAs and p21Cip1 in glioma: diagnostic, prognostic and therapeutic roles

Glioblastoma multiforme is considered one of the most common malignant primary intracranial tumors. Despite treatment with a combination of surgery, chemotherapy and radiotherapy, patients with glioblastoma multiform have poor prognosis. It has been widely accepted that the occurrence, progression, and even recurrence of glioblastoma multiforme strictly depends on the presence of glioma cancer stem cells. The presence of glioma stem cells reduces the efficacy of standard therapies, thus increasing the imperative to identify new targets and therapeutic strategies in glioblastoma patients. In this regard, the p21Cip1 pathway has been found to play an important role in the maintenance of the glioma stem cells. It has been shown that this pathway regulates cancer stem cell pool by preventing hyperproliferation and exhaustion. MicroRNAs, endogenous small non-coding RNAs, and long non-coding RNAs, regulate post-transcription gene expression. These are not only altered in glioma, but also in other cancer types, and are involved in tumor development and progression. Notably, they have also been shown to modulate the expression of proteins in the p21Cip1 signaling pathway. This review highlights the extent and complexity of cross-talk between microRNAs, long non-coding RNAs and the p21Cip1 pathway, and demonstrates how such interplay orchestrates the regulation of protein expression and functions in glioma and glioma stem cells