The aggressive behavior of Glioblastoma multiforme (GBM) is mainly due to high invasiveness and proliferation rate as well as to high resistance to standard chemotherapy. Several chemotherapeutic agents like temozolomide (TMZ), carmustine (BCNU) or doxorubicin (DOXO) have been employed for treatment of GBM, but they display limited efficacy. Therefore, it is important to identify new treatment modalities to improve therapeutic effects and enhance GBM chemosensitivity. Recently, activation of the transient receptor potential vanilloid type 2 (TRPV2) has been found to inhibit human GBM cell proliferation and overcome BCNU resistance of GBM cells. Herein, we evaluated the involvement of cannabidiol (CBD)-induced TRPV2 activation, in the modulation of glioma cell chemosensitivity to TMZ, BCNU and DOXO. We found that CBD increases TRPV2 expression and activity. CBD by triggering TRPV2-dependent Ca(2+) influx increases drug uptake and synergizes with cytotoxic agents to induce apoptosis of glioma cells, whereas no effects were observed in normal human astrocytes. Moreover, as the pore region of transient receptor potential (TRP) channels is critical for ion channel permeation, we demonstrated that deletion of TRPV2 poredomain inhibits CBD-induced Ca(2+) influx, drug uptake and cytotoxic effects. Overall, we demonstrated that co-administration of cytotoxic agents together with the TRPV2 agonist CBD increases drug uptake and parallelly potentiates cytotoxic activity in human glioma cells.
Glioma stem-like cells (GSCs) correspond to a tumor cell subpopulation, involved in glioblastoma multiforme (GBM) tumor initiation and acquired chemoresistance. Currently, drug-induced differentiation is considered as a promising approach to eradicate 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 differentiated GSCs. Since it was demonstrated that CBD induces also TRPV2 expression and that TRPV2 is involved in GSCs differentiation, 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. Altogether, 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.
BackgroundIn this retrospective analysis, we explored the prognostic and predictive value of the systemic immune-inflammation index (SII), based on lymphocyte, neutrophil, and platelet counts, at baseline and changes at week 6 during first-line sunitinib in patients with metastatic renal cell cancer (RCC).ResultsPatients were stratified into high SII (≥ 730) and low SII (< 730) groups. SII was associated with objective response, p < 0.0001. The median PFS was 6.3 months (95% CI 5.5–8.9) in patients with SII ≥ 730 and 18.7 months (95% CI 14.7–22.8) in those with SII < 730, p < 0.0001. The median OS was 43.6 months (95% CI 35.3–52.1) in patients with SII < 730, and 13.5 months (95% CI 9.8–18.5) in those with SII ≥ 730, p < 0.0001. In multivariate analysis, performance status, IMDC score and SII were able to predict OS (HR = 3.29, HR = 1.71 and HR = 1.79, respectively).Materials and MethodsWe included 335 consecutive RCC patients treated with first-line sunitinib. The X-tile 3.6.1 software (Yale University, New Haven, CT) was used for bioinformatic analysis of the data to determine the cutoff value of SII. Progression-free survival (PFS), overall survival (OS) and their 95% confidence interval (95% CI) were estimated by Kaplan-Meier method and compared with logrank test. The impact of SII conversion at week 6 of treatment on PFS and OS was evaluated by Cox regression analyses.ConclusionsThe SII and its changes during treatment represent a powerful prognostic indicator of clinical outcome in patients with metastatic RCC.
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