Biology subjects

Joubran, S.

Publications and source records attributed to Joubran, S..

3 recordsLinked to original sources

bioRxiv2025

EGFR-targeted affibody-polyIC polyplex kills EGFR-overexpressing cancer cells without activating the EGFR

The epidermal growth factor receptor (EGFR) is aberrantly activated in many human epithelial cancers. This report presents the preparation, purification, and the anti-cancer potency of an anti-EGFR affibody (ZEGFR 1907)-polyethylenimine (PEI)-polyIC complex (PPEA-polyplex). Surface plasmon resonance analysis showed that the ZEGFR 1907 affibody binds tightly to full-length sEGFR with an average equilibrium dissociation constant, KD, value of 6.74 nM. The PPEA-polyplex does not activate the EGFR kinase, but kills tumor cells expressing medium to high levels of EGFR. The PPEA-polyplex stimulates the release of chemotactic cytokines (e.g., GRO-, IFN-{gamma}-inducible protein-10) and promoted PBMC-mediated bystander killing of non-transfected tumor cells. The PPEA-polyplex inhibited the growth of human epidermoid vulval carcinoma (A431) xenografts growing in immunocompromised nude mice. PPEA-polyplexes have the potential to inhibit the growth of tumors in Triple-negative breast cancer (TNBC) patients and other cancers which over-express the EGFR.

cancer biology↗

bioRxiv2025

Genetic variation reveals a homeotic long noncoding RNA that modulates human hematopoietic stem cells

The HOXA gene locus coordinates body patterning, hematopoiesis, and differentiation. While studying blood phenotype-associated variation within the HOXA locus, we identified a genetic variant, rs17437411, associated with globally reduced blood counts, protection from blood cancers, and variation in anthropometric phenotypes. We find that this variant disrupts the activity of a previously unstudied antisense long non-coding RNA (lncRNA) located between HOXA7 and HOXA9, which we have named HOTSCRAMBL. The HOTSCRAMBL variant disrupts lncRNA function and reduces human hematopoietic stem cell (HSC) self-renewal. Mechanistically, HOTSCRAMBL enables appropriate expression and splicing of HOXA genes in HSCs, most notably HOXA9, in an SRSF2-dependent manner. Given the critical role of HOXA gene expression in some blood cancers, we also demonstrate that HOTSCRAMBL variation or deletion compromises HOXA-dependent acute myeloid leukemias. Collectively, we show how insights from human genetic variation can uncover critical regulatory processes required for effective developmental gene expression.

genetics↗

bioRxiv2024

Transcription factor networks disproportionately enrich for heritability of blood cell phenotypes

Most phenotype-associated genetic variants map to non-coding regulatory regions of the human genome. Moreover, variants associated with blood cell phenotypes are enriched in regulatory regions active during hematopoiesis. To systematically explore the nature of these regions, we developed a highly efficient strategy, Perturb-multiome, that makes it possible to simultaneously profile both chromatin accessibility and gene expression in single cells with CRISPR-mediated perturbation of a range of master transcription factors (TFs). This approach allowed us to examine the connection between TFs, accessible regions, and gene expression across the genome throughout hematopoietic differentiation. We discovered that variants within the TF-sensitive accessible chromatin regions, while representing less than 0.3% of the genome, show a [~]100-fold enrichment in heritability across certain blood cell phenotypes; this enrichment is strikingly higher than for other accessible chromatin regions. Our approach facilitates large-scale mechanistic understanding of phenotype-associated genetic variants by connecting key cis-regulatory elements and their target genes within gene regulatory networks.

genomics↗