Endothelial Phosphatase VE-PTP Participates in Vasculogenic Mimicry by Preventing Autophagic Degradation of VE-Cadherin.

Aberrant extra-vascular expression of VE-cadherin has been observed in metastasis associated with Vasculogenic Mimicry (VM); we have recently shown that in VM prone cells VE-cadherin is mainly in the form of phospho-VE-cadherin in Y658 allowing increased plasticity that potentiates VM development in malignant cells. In the current study, we present results to show that human malignant melanoma cells VM+, express the VE-cadherin phosphatase VE-PTP. VE-PTP forms a complex with VE-Cadherin and p120-catenin and the presence of this complex act as a safeguard to prevent VE-Cadherin protein degradation by autophagy. Indeed, VE-PTP silencing results in complete degradation of VE-cadherin with the features of autophagy. In summary, this study shows that VE-PTP is involved in VM formation and disruption of VE-PTP/VE-Cadherin/p120 complex results in enhanced autophagy in aggressive VM+ cells. Thus, we identify VE-PTP as a key player in VM development by regulating VE-cadherin protein degradation through autophagy.

The influence of gender and body dissatisfaction on body-related attentional bias: An eye-tracking and virtual reality study.

OBJECTIVE: In the attentional bias (AB) phenomenon, eating disorder (ED) patients show a tendency to pay more attention to self-attributed unattractive body parts than to other body parts. However, little research has focused on gender differences in body-related attention, controlling for body dissatisfaction (BD). This study aimed to assess gender differences in AB toward specific weight- or nonweight-related body parts using a virtual reality (VR)-based embodiment technique and an eye-tracking AB assessment. METHOD: Forty-five women (23 with high BD and 22 with low BD) and 40 men (20 with high BD and 20 with low BD) were subsequently embodied in three virtual avatars, the first based on the participant's actual measurements, the second being larger than the participant, and the third being the same as the first avatar. The number of fixations and complete fixation time on weight-related areas of interest (W-AOIs) and nonweight-related areas of interest (NW-AOIs) were recorded for the three assessment time/avatars. RESULTS: The results showed a statistically significant interaction between gender and time for total fixation time and number of fixations (p < .05). BD levels did not significantly affect the results. Overall, women paid more attention to the W-AOIs than men, who in turn paid more attention to the NW-AOIs. Furthermore, preliminary evidence was found for an AB toward muscular-related AOIs among men. CONCLUSIONS: This study provides new information about gender differences and BD in gaze pattern behaviors. Future psychological ED assessments and treatments could take advantage of the possibilities of VR while real-time AB is objectively measured.

PIM kinases mediate resistance of glioblastoma cells to TRAIL by a p62/SQSTM1-dependent mechanism.

Glioblastoma (GBM) is the most common and aggressive brain tumor and is associated with poor prognosis. GBM cells are frequently resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and finding new combinatorial therapies to sensitize glioma cells to TRAIL remains an important challenge. PIM kinases are serine/threonine kinases that promote cell survival and proliferation and are highly expressed in different tumors. In this work, we studied the role of PIM kinases as regulators of TRAIL sensitivity in GBM cells. Remarkably, PIM inhibition or knockdown facilitated activation by TRAIL of a TRAIL-R2/DR5-mediated and mitochondria-operated apoptotic pathway in TRAIL-resistant GBM cells. The sensitizing effect of PIM knockdown on TRAIL-induced apoptosis was mediated by enhanced caspase-8 recruitment to and activation at the death-inducing signaling complex (DISC). Interestingly, TRAIL-induced internalization of TRAIL-R2/DR5 was significantly reduced in PIM knockdown cells. Phospho-proteome profiling revealed a decreased phosphorylation of p62/SQSTM1 after PIM knockdown. Our results also showed an interaction between p62/SQSTM1 and the DISC that was reverted after PIM knockdown. In line with this, p62/SQSTM1 ablation increased TRAIL-R2/DR5 levels and facilitated TRAIL-induced caspase-8 activation, revealing an inhibitory role of p62/SQSTM1 in TRAIL-mediated apoptosis in GBM. Conversely, upregulation of TRAIL-R2/DR5 upon PIM inhibition and apoptosis induced by the combination of PIM inhibitor and TRAIL were abrogated by a constitutively phosphorylated p62/SQSTM1S332E mutant. Globally, our data represent the first evidence that PIM kinases regulate TRAIL-induced apoptosis in GBM and identify a specific role of p62/SQSTM1Ser332 phosphorylation in the regulation of the extrinsic apoptosis pathway activated by TRAIL.

PARP targeting counteracts gliomagenesis through induction of mitotic catastrophe and aggravation of deficiency in homologous recombination in PTEN-mutant glioma.

Glioblastoma multiforme (GBM) is the most common primary brain tumour in adults and one of the most aggressive cancers. PARP-1 is a nuclear protein involved in multiple facets of DNA repair and transcriptional regulation. In this study we dissected the action of PARP inhibition in different GBM cell lines with either functional or mutated PTEN that confers resistance to diverse therapies. In PTEN mutant cells, PARP inhibition induced a severe genomic instability, exacerbated homologous recombination repair (HR) deficiency and down-regulated the Spindle Assembly Checkpoint (SAC) factor BUBR1, leading to mitotic catastrophe (MC). EGFR gene amplification also represents a signature of genetic abnormality in GBM. To more effectively target GBM cells, co-treatment with a PARP inhibitor and an EGFR blocker, erlotinib, resulted in a strong suppression of ERK1/2 activation and in vivo the combined effect elicited a robust reduction in tumour development. In conclusion, PARP inhibition targets PTEN-deficient GBM cells through accentuation of SAC repression and aggravation of HR deficiency, leading to the induction of genomic instability and eventually deriving to mitotic catastrophe (MC); the inhibition of PARP and co-treatment with an inhibitor of pro-survival pathways strongly retarded in vivo gliomagenesis.