Biology subjects

Voutetakis, K.

Publications and source records attributed to Voutetakis, K..

3 recordsLinked to original sources

bioRxiv2024

Molecular and functional profiling unravels targetable vulnerabilities in colorectal cancer

While colorectal cancer (CRC) patients with microsatellite instability (MSI) respond well to immunotherapy those with microsatellite stable (MSS) tumors rely on conventional chemotherapy, often with poor outcomes. Both types frequently carry mutations in KRAS or BRAF proto-oncogenes, rendering them more resistant to treatment. New therapeutic biomarkers and treatments remain a clinical need, especially for MSS tumors. We performed whole exome and RNA-Sequencing from 28 tumors of the Athens Comprehensive Cancer Center CRC cohort, and molecularly characterized colorectal cancer patients based on their MSI status, SNVs/CNAs, and pathway/transcription factor activities at the individual patient level. Variants were classified using a new computational score for integrative cancer variant annotation and prioritization. Complementing this molecular data with public multi-omics datasets, we identified activation of transforming growth factor beta (TGF{beta}) signaling to be stronger activated in the MSS patients whereas JAK-STAT and MAPK molecular cascades were activated specifically in MSI. We unraveled mechanisms consistently perturbed in the transcriptional and mutational circuits and identified RUNX transcription factors as putative novel targets. Assessing the immunogenicity of CRC tumors in the context of RAS/RAF mutations and MSI/MSS status revealed a critical impact KRAS mutations have on immunogenicity particularly in the MSS patient subgroup, with implications for diagnosis and treatment.

cancer biology↗

bioRxiv2019

Constitutive IRE1α signaling maintains glioblastoma cell differentiation

Endoplasmic Reticulum (ER) proteostasis control and the Unfolded Protein Response (UPRER) have been shown to contribute to tumor development and aggressiveness. As such, the UPRER sensor IRE1 (referred to as IRE1 hereafter) is a major regulator of glioblastoma (GBM) development and is an appealing therapeutic target. To document IRE1 suitability as an antineoplastic pharmacological target, we investigated how this protein contributed to GBM cell reprogramming, a property involved in treatment resistance and disease recurrence. Probing the IRE1 activity molecular signature on transcriptome datasets of human tumors, showed that high IRE1 activity correlated with low expression of the main GBM stemness transcription factors SOX2, SALL2, POU3F2 and OLIG2. Henceforth, this phenotype was pharmacologically and genetically recapitulated in immortalized and primary GBM cell lines as well as in mouse models. We demonstrated that constitutive activation of the IRE1/XBP1/miR148a signaling axis repressed the expression of SOX2 and led to maintenance of a differentiation phenotype in GBM cells. Our results describe a novel role for IRE1 signaling in maintaining differentiated tumor cell state and highlight opportunities of informed IRE1 modulation utility in GBM therapy.

cancer biology↗

bioRxiv2019

IRE1-UBE2D3 signaling controls the recruitment of myeloid cells to glioblastoma.

Tumor cells are exposed to intrinsic and environmental challenges that trigger endoplasmic reticulum (ER) homeostasis alteration, in turn leading to ER stress. To cope with this, tumor cells engage an adaptive signaling pathway, the unfolded protein response (UPR) thus promoting the acquisition of malignant features. As such, glioblastoma multiforme (GBM), the most aggressive primary brain tumors, exhibit constitutive UPR signals to sustain growth. Herein, we showed that signaling elicited by one of the UPR sensors, IRE1, promotes GBM tumor invasion, angiogenesis and infiltration by macrophages. Hence, high IRE1 activity in tumors predicts worse outcome. We further dissect IRE1-dependent mechanisms that shape the brain tumor immune microenvironment towards myeloid cells. We identify an IRE1-dependent signaling pathway that directly controls the expression/release of proinflammatory chemokines (CXCL2, IL6, IL8) leading to tumor cell-mediated chemoattraction of neutrophils and macrophages. This pathway requires XBP1 non-conventional mRNA splicing and XBP1s-dependent expression of the E2 ubiquitin enzyme UBE2D3. The latter contributes to the degradation of the NF{kappa}B inhibitor I{kappa}B, leading to the up-regulation of proinflammatory chemokines. Our work identifies a novel IRE1/UBE2D3 proinflammatory signaling axis instrumental to pro-tumoral immune regulation of GBM.

cancer biology↗