Biology subjects

Heravi-Moussavi, A.

Publications and source records attributed to Heravi-Moussavi, A..

3 recordsLinked to original sources

bioRxiv2024

Composite impact of genome-wide APOBEC mutations and HLA haplotype on cancer immunogenicity has a sex-biased survival impact

APOBEC3A and APOBEC3B genome mutators drive tumor evolution and drug resistance but may also generate neoepitopes for cytotoxic T cells (CTL). Given the extensive polymorphism of Class I HLA, the CTL immunopeptidome, comprised of all 8-11mer peptides presented by an individuals six HLA class I alleles, varies person-to-person. We predicted the genome-wide impact of APOBEC3A/B-driven mutations on the immunogenicity of the immunopeptidomes of several thousand class I HLA alleles. Analysis of several billion APOBEC3-mediated mutations revealed that HLA class I alleles vary markedly in the susceptibility of their immunopeptidome to mutations. A subset of alleles of A1-A3 and B44 supertype supported increased neoepitopes. Notably, the immunogenicity changes supported by an individuals HLA class I alleles in response to APOBEC3 mutations predict survival in APOBEC3-mutated tumors and correlate with CTL activation. Thus, immunogenicity changes mediated by APOBEC3s impact survival, making HLA class I genotype a prognostic marker in APOBEC3-mutated tumors.

cancer biology↗

bioRxiv2021

Epithelial-mesenchymal plasticity induced by discontinuous exposure to TGFβ1 promotes tumour growth

Transitions between epithelial and mesenchymal cellular states (EMT/MET) contribute to cancer progression. We hypothesize that EMT followed by MET promotes cell population heterogeneity favouring tumour growth. We developed an EMT model by on/off exposure of epithelial EpH4 cells (E-cells) to TGF{beta}1 that mimics phenotypic EMT (M-cells) and MET. We aimed at understanding whether phenotypic MET is accompanied by molecular and functional reversion back to epithelia, by using RNA sequencing, Immunofluorescence (IF), proliferation, wound healing, focus formation and mamosphere formation assays, as well as cell-xenografts in nude mice. Phenotypic reverted-epithelial cells (RE-cells), obtained after MET induction, presented pure epithelial morphology and proliferation rate resembling E-cells. However, RE transcriptomic profile and IF staining of epithelial and mesenchymal markers revealed a unique and heterogeneous mixture of cell-subpopulations, with high self-renewal ability fed by oxidative phosporylation. RE-cells heterogeneity is stably maintained for long periods after TGF{beta}1 removal, both in vitro and in large derived tumours in nude mice. Overall, we show that phenotypic reverted-epithelial cells (RE-cells) do not return to the molecular and functional epithelial state, present mesenchymal features related with aggressiveness and cellular heterogeneity that favour tumour growth in vivo. This work strengthens epithelial cells reprogramming and cellular heterogeneity fostered by inflammatory cues as a tumour-growth promoting factor in vivo.

cell biology↗

bioRxiv2019

Polycomb contraction differentially regulates terminal human hematopoietic differentiation programs

Lifelong production of the many types of mature blood cells from less differentiated progenitors is a hierarchically ordered process that spans multiple cell divisions. The nature and timing of the molecular events required to integrate the environmental signals, transcription factor activity, epigenetic modifications, and changes in gene expression involved are thus complex and still poorly understood. We now show that the more primitive types of human cells in this system display a unique repressive H3K27me3 signature that is retained by mature lymphoid cells but is lost in terminally differentiated monocytes and erythroblasts. Additional intervention data implicate that control of this chromatin state change is a requisite part of the process, whereby normal human hematopoietic progenitor cells make lymphoid and myeloid fate decisions.

cell biology↗