Biology subjects

Schlesinger, M.

Publications and source records attributed to Schlesinger, M..

3 recordsLinked to original sources

bioRxiv2019

Glutathione Peroxidase 8 (GPX8)-IL6 axis is essential in maintaining breast cancer mesenchymal stem-like state and aggressive phenotype

Metabolic reprogramming as a downstream result of oncogenic signaling pathways has been described as a hallmark of cancer. Here, we describe a reverse scenario in which a metabolic enzyme regulates cancer cell behavior by triggering a signaling pathway. We find that glutathione peroxidase 8 (GPX8), a poorly characterized redox enzyme that resides in the endoplasmic reticulum, is upregulated during the epithelial-to-mesenchymal (EMT) program in HMLE and A549 cells. In cancer patients, high tumor levels of GPX8 correlate with mesenchymal markers and poor patient outcome. Strikingly, GPX8 knockout in mesenchymal-like cells results in an epithelial-like morphology, downregulation of EMT characteristics, loss of cancer stemness features, and impeded tumor initiation in mice. We determine the mechanism governing this reduction in cancer aggressiveness is through the repression of crucial autocrine factors, in particular, interleukin-6 (IL-6). Specifically, GPX8 knockout impairs IL-6-driven activation of the JAK-STAT3 signaling pathway, a critical regulator of a cancer-aggressive state. Altogether, we uncover the GPX8-IL-6 axis as a novel metabolic-inflammatory pathway that acts as a robust EMT activator and program to induce aggressive cancer cell characteristics.

cancer biology↗

bioRxiv2019

PDGFRA Defines the Mesenchymal Stem Cell Kaposi’s Sarcoma Progenitors by Enabling KSHV Oncogenesis in an Angiogenic Environment

Kaposis sarcoma (KS) is an AIDS-defining cancer caused by the KS-associated herpesvirus (KSHV). Unanswered questions regarding KS are its cellular ontology and the conditions conducive to viral oncogenesis. We identify PDGFRA(+)/SCA-1(+) bone marrow-derived mesenchymal stem cells (P(+)S MSCs) as KS spindle-cell progenitors and found that pro-angiogenic environmental conditions typical of KS are critical for KSHV sarcomagenesis. This is because growth in KS-like conditions generates a de-repressed KSHV epigenome allowing oncogenic KSHV gene expression in infected P(+)S MSCs. Furthermore, these growth conditions allow KSHV-infected P(+)S MSCs to overcome KSHV-driven oncogene-induced senescence and cell cycle arrest via a PDGFRA-signaling mechanism; thus identifying PDGFRA not only as a phenotypic determinant for KS-progenitors but also as a critical enabler for viral oncogenesis.\n\nAUTHOR SUMMARYIdentification of the KS progenitor cell creates the possibility of studying viral oncogenesis and its determinants from its initial steps as a continuum. It also increases our understanding of pathogenic mechanisms and disease preferential tropism. Hereby we identify P(+)S-MSCs as KS progenitors, in which KSHV infection has oncogenic consequences; only when these cells are in a pro-angiogenic environment in which PDGFRA activation enables an oncogenic de-repressed KSHV epigenome. These results identify a KS-progenitor population in the P(+)S-MSCs and point to pro-angiogenic environmental conditions as essential for oncogenic viral gene expression and transformation. We designed a novel model of KSHV oncogenesis, creating a very robust platform to identify KSHV oncogenic pathways and their relationship with cellular lineages and extracellular growth environments.

cancer biology↗

bioRxiv2018

Procyclic Trypanosoma brucei cell cycle is impaired at the G1 stage by the presence of poly(ADP-ribose) in the nucleus

Previously we demonstrated that an excess of poly (ADP-ribose) in the nucleus makes procyclic parasites more sensitive to hydrogen peroxide. However, the effect of an altered-PAR metabolism under standard conditions has not been addressed yet. Here we have analyzed the behavior of the growth curve of transgenic parasites that present this phenotype and studied cell cycle progression in synchronized cultures by flow cytometry and immunofluorescence. We have demonstrated that an excess of nuclear poly (ADP-ribose) produces a delay in the G1 phase of the cell cycle. Moreover, for the first time we have shown that poly (ADP-ribose) occurs at specific points very close to the mature basal body, suggesting there could be a link between the kinetoplast and poly (ADP-ribose) metabolism.

cell biology↗