Anti-VTCN1 Monoclonal antibody, clone 299 [PE]

Human placental development during early pregnancy is poorly understood. Many conceptuses are lost at this stage. It is thought that preeclampsia, intrauterine growth restriction and other placental syndromes that manifest later in pregnancy may originate early in placentation. Thus, there is a need for models of early human placental development. Treating human embryonic stem cells (hESCs) with BMP4 (bone morphogenic protein 4) plus A83-01 (ACTIVIN/NODAL signaling inhibitor) and PD173074 (fibroblast growth factor 2 or FGF2 signaling inhibitor) (BAP conditions) induces differentiation to the trophoblast lineage (hESC(BAP)), but it is not clear which stage of trophoblast differentiation these cells resemble. Here, comparison of the hESC(BAP) transcriptome to those of trophoblasts from human blastocysts, trophoblast stem cells and placentas collected in the first-third trimester of pregnancy by principal component analysis suggests that hESC after 8 days BAP treatment most resemble first trimester syncytiotrophoblasts. To further test this hypothesis, transcripts were identified that are expressed in hESC(BAP) but not in cultures of trophoblasts isolated from term placentas. Proteins encoded by four genes, GABRP (gamma-aminobutyric acid type A receptor subunit Pi), WFDC2 (WAP four-disulfide core domain 2), VTCN1 (V-set domain containing T-cell activation inhibitor 1) and ACTC1 (actin alpha cardiac muscle 1), immunolocalized to placentas at 4-9 weeks gestation, and their expression declined with gestational age (R-2 = 0.61-0.83). None are present at term. Expression was largely localized to syncytiotrophoblast of both hESC(BAP) cells and placental material from early pregnancy. WFDC2, VTCN1 and ACTC1 have not previously been described in placenta. These results support the hypothesis that hESC(BAP) represent human trophoblast analogous to that of early first trimester and are a tool for discovery of factors important to this stage of placentation.

To facilitate development of cancer stem cell (CSC)-targeting therapies, we analyzed publicly available breast cancer data sets to identify genes coexpressed with sex-determining region Y (SRY)-related high-mobility group (HMG) box-containing factor 10 (SOX10), a neural crest marker, and prominin 1 (PROM1)/CD133,a common CSC marker. The conserved SOX10/PROM1 gene signature that we characterized supports the existence in basal breast cancers of SOX10-positive (SOX10(+))/CD133(+) cells with neural stem-like features exposing clinically relevant CSC markers and signaling networks. Background: We previously characterized in salivary adenoid cystic carcinoma (ACC) a novel population of cancer stem cells (CSCs) marked by coexpression of 2 sternness genes, sex-determining region Y (SRY)-related HMG box-containing factor 10 (SOX10) and CD133. We also reported that in ACC and basal-like breast carcinoma (BBC), a triple-negative breast cancer subtype, expression of SOX10 similarly demarcates a highly conserved gene signature enriched with neural stem cell genes. On the basis of these findings, we hypothesized that BBC might be likewise driven by SOX10 positive (S0X10(+))/CD133(+) cells with neural stem cell properties. Materials and Methods: To validate our hypothesis on clinical data, we used a novel approach to meta-analysis that merges gene expression data from independent breast cancer studies and ranks genes according to statistical significance of their coexpression with the gene of interest. Genes that showed strong association with CD133/PROM1 as well as SOX10 were validated across different platforms and data sets and analyzed for enrichment with genes involved in neurogehesis. Results: We identified in clinical breast cancer data sets a highly conserved SOX10/PROM1 gene signature that contains neural stem cell markers common for Schwann cells, ACC, BBC, and melanoma. Identification of tripartite motif-containing 2 (TRIM2), TRIM29, MPZL2, potassium calcium-activated channel subfamily N member 4 (KCNN4), and V-set domain containing T cell activation inhibitor 1 (VTCN1)/B7 homolog 4 (B7H4) within this signature provides insight into molecular mechanisms of CSC maintenance. Conclusion: Our results suggest that BBC is driven by SOX10-VCD133(+) cells that express neural stem cell-specific markers and share molecular similarities with CSCs of neural crest origin. Our study provides clinically relevant information on possible drivers of these cells that might facilitate development of CSC targeting therapies against this cancer distinguished with poor prognosis and resistance to conventional therapies.