Biology subjects

Vaz, J. M.

Publications and source records attributed to Vaz, J. M..

3 recordsLinked to original sources

bioRxiv2023

Characterizing heterogeneity along EMT and metabolic axes in colorectal cancer reveals underlying consensus molecular subtype-specific trends

Colorectal cancer (CRC) is highly heterogenous with variable survival outcomes and therapeutic vulnerabilities. A commonly used classification system in CRC is the Consensus Molecular Subtypes (CMS) based on gene expression patterns. However, how these CMS categories connect to axes of phenotypic plasticity and heterogeneity remains unclear. Here, we analyze 101 bulk transcriptomic datasets, along with patient tumor samples from TCGA and single-cell RNA sequencing data, to evaluate the extent of variation among CMS subtypes across metabolic plasticity and EMT axes. Our results show that CMS2 and CMS3 samples were relatively more epithelial as compared to CMS1 and CMS4. Single-cell RNA-seq analysis of CMS1 revealed two subpopulations: one close to CMS4 (more mesenchymal) and the other closer to CMS2 or CMS3 (more epithelial), indicating a partial EMT-like behavior. Further, in our meta-analysis and in TCGA data, epithelial phenotype score was positively correlated with scores of glycolysis, OXPHOS and FAO pathways, while mesenchymal scores showed CMS subtype-specific associations with metabolic axes. PD-L1 activity scores, however, consistently correlated positively with mesenchymal signature ones and negatively with epithelial signature ones, across the four CMS categories. Together, our results quantify the patterns of two interconnected axes of phenotypic heterogeneity - EMT and metabolic reprogramming - at a CMS subtype level in CRC.

cancer biology↗

bioRxiv2023

Dual role of CASP8AP2/FLASH in regulating epithelial-to-mesenchymal (EMT) plasticity

Metastasis consists of sequential steps initiated by cancer cells invading from the primary tumor site into neighboring tissues, followed by entry into the circulatory system and completed by extravasation and growth in distal organs where secondary tumors are formed. Circulating tumor cells, thus, encounter and adapt to multiple environmental changes during their transition from the primary to the secondary tumor sites. Epithelial-to-mesenchymal transition (EMT) is a developmental program that consists of loss of epithelial features concomitant with acquisition of mesenchymal features. Activation of EMT in cancer facilitates acquisition of aggressive traits and cancer invasion. EMT plasticity (EMP), the dynamic transition between multiple hybrid states in which cancer cells display both epithelial and mesenchymal phenotypes, confers survival advantages for cancer cells in the constantly changing environment. Therefore, understanding the molecular mechanisms regulating intermediate phenotypic states along the E-M spectrum is critical. Core EMT transcription factors (EMT-TFs), ZEB, SNAI and TWIST families, play an important role in EMT and its plasticity. In the present study we characterize FLASH as a regulator of EMP and multiple EMT-TFs. We demonstrate that loss of FLASH gives rise to a hybrid E/M phenotype with high epithelial scores even in the presence of TGF{beta}, as determined by computational methods using expression of predetermined sets of epithelial and mesenchymal genes. We demonstrate that FLASH is regulating expression of multiple cell junction proteins with an established role in cancer progression and that its role in EMT is independent of its histone biogenesis role. Further, we show that FLASH expression in cancer lines is inversely correlated with the epithelial score, consistent with its function as a repressor of the epithelial phenotype. Nonetheless, activation of a distinct set of mesenchymal markers concomitant with epithelial markers reveals the complex role of FLASH in EMT and indicates that intermediate E/M states could arise from opposing control by FLASH on different families of EMT-TFs.

cancer biology↗

bioRxiv2022

Partial EMT and associated changes in cellular plasticity in oncovirus-positive samples

Oncoviruses exploit diverse host mechanisms to survive and proliferate. These adaptive strategies overlap with mechanisms employed by malignant cells during their adaptation to dynamic micro-environments and for evasion of immune attack. While the role of individual oncoviruses in mediating cancer progression has been extensively characterized, little is known about the common gene regulatory features of oncovirus-induced cancers. Here, we focus on defining the interplay between several cancer hallmarks, including Epithelial-Mesenchymal Transition (EMT), metabolic alterations, and immune evasion across major oncoviruses by examining publicly available transcriptomics data sets containing both oncovirus-positive and oncovirus-negative samples. We observe that oncovirus-positive samples display varying degrees of EMT and metabolic reprogramming. While the progression of EMT generally associated with an enriched glycolytic metabolic program and suppressed fatty acid oxidation (FAO) and oxidative phosphorylation (OXPHOS), partial EMT correlated well with glycolysis. Furthermore, oncovirus-positive samples had higher activity and/or expression levels of immune checkpoint molecules, such as PD-L1, which was associated with a partial EMT program. These analyses thus decode common pathways in oncovirus-positive samples that may be used in pinpointing new therapeutic vulnerabilities for oncovirus-associated cancer cell plasticity.

cancer biology↗