Biology subjects

Yankson, G.

Publications and source records attributed to Yankson, G..

3 recordsLinked to original sources

bioRxiv2026

Therapeutic Potential of Dichapetalin M in Metastatic and ER-positive Breast Cancer: Evidence from Cell Line Studies

BackgroundDichapetalin M (Dic M), an active compound extracted from medicinal plants in the Dichapetalum genus, has been previously shown to possess anti-proliferative activity against cancer cell lines. However, the specific mechanism through which it exerts its anticancer effects remains unknown. PurposeThis study focused on elucidating the mechanism of action of dichapetalin M to further explore its potential as a therapeutic agent for resistant and metastatic breast cancer. MethodWe confirmed the Estrogen Receptor (ER) as a target of Dic M, using an in vitro approach. Furthermore, we examined both the apoptotic and migrastatic effects of dichapetalin M by assessing its impact on the expression of key apoptosis-related and cancer cell migration genes. Finally, we evaluated the compounds effect on Multi-drug Resistance Gene MDR1 expression, a gene linked to cancer drug resistance. ResultsOur target validation experiments demonstrated that Dic M exhibited considerably higher cytotoxicity in ER-positive breast cell lines compared to ER-negative cell lines. Furthermore, treatment of MCF-7 cells (which are ER-positive) with Dic M led to a dose-dependent increase in the expression of AREG (amphiregulin), a downstream effector of the Estrogen Receptor. Additionally, Dic M inhibited actin polymerization and significantly downregulated genes involved in the turnover of actin monomers. Scratch-wound assay results further demonstrate that Dic M reduces the rate of cell migration, although its impact on EMT-related gene expression was only observed at high doses. Additionally, Dic M treatment in MCF-7 cells resulted in a significant decrease in the expression of pro-apoptotic genes and MDR1 expression. ConclusionsThese findings indicate that Dic M likely interacts with the Estrogen Receptor and employs the apoptotic pathway to exert its cytotoxic and anti-proliferative effects. Dic M exhibits promising potential, such as anti-migrastatic properties and downregulation of a key breast cancer resistance gene, warranting further investigation.

cancer biology↗

bioRxiv2026

Dosage compensation defects due to roX RNA deletion are rescued by recalibration of X/autosome stoichiometry

Metazoa evolved regulatory networks to balance the expression of their sex chromosomes. In Drosophila, males have a single gene-rich X chromosome, whereas females have two. Balanced X/autosome expression is essential for viability, and in male flies is achieved by activation of genes on the X through the male-specific-lethal (MSL) dosage compensation complex (DCC). This ribonucleoprotein assembly contains long, non-coding roX RNAs. To dissect the functional requirements of roX in a cell-based system, we deleted the roX2 gene in male S2 cells and selected two independent lines lacking detectable roX RNA. In the absence of roX, the remaining MSL protein complex was unable to associate with known or newly identified binding sites and thus failed to activate transcription. Surprisingly, the X/autosome expression ratio appeared nevertheless compensated. Cytogenetic and genomic analyses revealed that both roX-deficient cell populations had acquired additional X chromosomes. Apparently, chromosome gains due to mis-segregation made up for the loss of DCC-mediated dosage compensation. Interestingly, ectopic expression of full-length roX2, but not of shortened derivatives, fully restored DCC binding and normalized the karyotype. These findings illustrate that X chromosome dosage compensation is critical for viability even in cultured cells and provide a striking example of rapid evolution under stringent selection. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=83 SRC="FIGDIR/small/707606v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1bbf907org.highwire.dtl.DTLVardef@1da43a9org.highwire.dtl.DTLVardef@903326org.highwire.dtl.DTLVardef@10e3865_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2023

Efficient Formation of Single-copy Human Artificial Chromosomes

Large DNA assembly methodologies underlie milestone achievements in synthetic prokaryotic and budding yeast chromosomes. While budding yeast control chromosome inheritance through [~]125 bp DNA sequence-defined centromeres, mammals and many other eukaryotes use large, epigenetic centromeres. Harnessing centromere epigenetics permits human artificial chromosome (HAC) formation but is not sufficient to avoid rampant multimerization of the initial DNA molecule upon introduction to cells. Here, we describe an approach that efficiently forms single-copy HACs. It employs a [~]750 kb construct that is sufficiently large to house the distinct chromatin types present at the inner and outer centromere, obviating the need to multimerize. Delivery to mammalian cells is streamlined by employing yeast spheroplast fusion. These developments permit faithful chromosome engineering in the context of metazoan cells. One-Sentence SummaryA quarter century after the first human artificial chromosomes, a solution to their uncontrolled multimerization is achieved.

molecular biology↗