The signal transducer CD24 suppresses the germ cell program and promotes an ectodermal rather than mesodermal cell fate in embryonal carcinomas
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Testicular germ cell tumors (GCTs) are stratified into seminomas and non-seminomas. Seminomas share many histological and molecular options with primordial germ cells, whereas the non-seminoma stem cell inhabitants – embryonal carcinoma (EC) – is pluripotent and thus in a position to differentiate into cells of all three germ layers (teratomas).
Moreover, ECs are able to differentiating into extra-embryonic lineages (yolk-sac tumors, choriocarcinomas). On this examine, we deciphered the molecular and (epi)genetic mechanisms regulating expression of CD24, a extremely glycosylated signaling molecule upregulated in lots of cancers. CD24 is overexpressed in ECs in comparison with different GCT entities and may be related to an undifferentiated pluripotent cell destiny.
We exhibit that CD24 may be transactivated by the pluripotency issue SOX2, which binds in proximity to the CD24 promoter. In GCTs, CD24 expression is managed by epigenetic mechanisms, i.e. histone acetylation, since CD24 may be induced by the applying histone deacetylase inhibitors. Vice versa, CD24 expression is downregulated upon inhibition of histone methyltransferases, E3-ubiquitin ligases or bromodomain (BRD) proteins.
Moreover, three-dimensional (3D) co-cultivation of EC cells with microenvironmental cells, reminiscent of fibroblasts, endothelial or immune cells, diminished CD24 expression, suggesting that crosstalk with the somatic microenvironment influences CD24 expression.
In a CRISPR/Cas9-deficiency mannequin, we exhibit that CD24 fulfils a bivalent position in differentiation by way of regulation of homeobox, phospho- and glycoproteins, i.e. it’s concerned in suppressing the germ cell/spermatogenesis program and mesodermal/endodermal differentiation, whereas poising the cells for ectodermal differentiation.
Lastly, blocking CD24 by a monoclonal antibody enhanced sensitivity in direction of cisplatin in EC cells, together with cisplatin-resistant subclones, highlighting CD24 as a putative goal together with cisplatin.
Human multipotent neural stem cells might successfully be used for the remedy of quite a lot of neurological issues. Nevertheless, a defining signature of neural stem cell traces that might be expandable, non-tumorigenic, and differentiate into fascinating neuronal/glial phenotype after in vivo grafting just isn’t but outlined.
Using a mass spectrometry strategy, primarily based on chosen response monitoring, we examined a panel of well-described tradition situations, and measured ranges of protein markers routinely used to probe neural differentiation. Our multiplexed assay enabled us to concurrently determine the presence of pluripotent, multipotent, and lineage-committed neural cells, thus representing a robust device to optimize novel and extremely particular propagation and differentiation protocols.
The multiplexing capability of this technique permits the addition of different newly recognized cell type-specific markers to additional enhance the specificity and quantitative accuracy in detecting focused cell populations. Such an expandable assay could achieve the benefit over conventional antibody-based assays, and represents a technique of selection for high quality management of neural stem cell traces meant for medical use.
Acute myeloid leukemia (AML) has a poor prognosis below the present normal of care. In recent times, venetoclax, a BCL-2 inhibitor, was accredited to deal with sufferers, ineligible for intensive induction chemotherapy. Full remission charges with venetoclax-based therapies are, nonetheless, hampered by minimal residual illness (MRD) in a proportion of sufferers, resulting in relapse.
MRD is because of leukemic stem cells retained in bone marrow protecting environments; activation of the CXCL12/CXCR4 pathway was proven to be related to this course of. An necessary position can be performed by cell adhesion molecules reminiscent of CD44, which has been proven to be essential for AML growth.
Right here we present that CD44 is concerned in CXCL12 promotion of resistance to venetoclax-induced apoptosis in human AML cell traces and AML affected person samples which may very well be abrogated by CD44 knockdown, knockout or blocking with an anti-CD44 antibody. Break up-Venus biomolecular fluorescence complementation confirmed that CD44 and CXCR4 bodily affiliate on the cell membrane upon CXCL12 induction.
Within the venetoclax-resistant OCI-AML3 cell line, CXCL12 promoted a rise within the proportion of cells expressing excessive ranges of embryonic-stem-cell core transcription components, abrogated by CD44 knockdown. This ESC-TF-expressing subpopulation which may very well be chosen by venetoclax remedy, exhibited a basally-enhanced resistance to apoptosis, and expressed increased ranges of CD44.
Lastly, we developed a novel AML xenograft mannequin in zebrafish, exhibiting that CD44 knockout sensitizes OCI-AML3 cells to venetoclax remedy in vivo. Our examine reveals that CD44 is a possible molecular goal to sensitize AML cells to venetoclax-based therapies.