E-cadherin and p120 catenin (p120) are essential for epithelial homeostasis, but can also exert pro-tumorigenic activities. Here, we resolve this apparent paradox by identifying two spatially and functionally distinct junctional complexes in non-transformed polarized epithelial cells: one growth suppressing at the apical zonula adherens (ZA), defined by the p120 partner PLEKHA7 and a non-nuclear subset of the core microprocessor components DROSHA and DGCR8, and one growth promoting at basolateral areas of cell–cell contact containing tyrosine-phosphorylated p120 and active Src. Recruitment of DROSHA and DGCR8 to the ZA is PLEKHA7 dependent. The PLEKHA7–microprocessor complex co-precipitates with primary microRNAs (pri-miRNAs) and possesses pri-miRNA processing activity. PLEKHA7 regulates the levels of select miRNAs, in particular processing of miR-30b, to suppress expression of cell transforming markers promoted by the basolateral complex, including SNAI1, MYC and CCND1. Our work identifies a mechanism through which adhesion complexes regulate cellular behaviour and reveals their surprising association with the microprocessor.

We used deep sequencing technology to profile the transcriptome, gene copy number, and CpG island methylation status simultaneously in eight commonly used breast cell lines to develop a model for how these genomic features are integrated in estrogen receptor positive (ER+) and negative breast cancer. Total mRNA sequence, gene copy number, and genomic CpG island methylation were carried out using the Illumina Genome Analyzer. Sequences were mapped to the human genome to obtain digitized gene expression data, DNA copy number in reference to the non-tumor cell line (MCF10A), and methylation status of 21,570 CpG islands to identify differentially expressed genes that were correlated with methylation or copy number changes. These were evaluated in a dataset from 129 primary breast tumors. Gene expression in cell lines was dominated by ER-associated genes. ER+ and ER− cell lines formed two distinct, stable clusters, and 1,873 genes were differentially expressed in the two groups. Part of chromosome 8 was deleted in all ER− cells and part of chromosome 17 amplified in all ER+ cells. These loci encoded 30 genes that were overexpressed in ER+ cells; 9 of these genes were overexpressed in ER+ tumors. We identified 149 differentially expressed genes that exhibited differential methylation of one or more CpG islands within 5 kb of the 5′ end of the gene and for which mRNA abundance was inversely correlated with CpG island methylation status. In primary tumors we identified 84 genes that appear to be robust components of the methylation signature that we identified in ER+ cell lines. Our analyses reveal a global pattern of differential CpG island methylation that contributes to the transcriptome landscape of ER+ and ER− breast cancer cells and tumors. The role of gene amplification/deletion appears to more modest, although several potentially significant genes appear to be regulated by copy number aberrations.

We performed a first-in-disease trial of in vivo CD28:CD80/86 costimulation blockade with abatacept for acute graft-versus-host disease (aGVHD) prevention during unrelated-donor hematopoietic cell transplantation (HCT). All patients received cyclosporine/methotrexate plus 4 doses of abatacept (10 mg/kg/dose) on days -1, +5, +14, +28 post-HCT. The feasibility of adding abatacept, its pharmacokinetics, pharmacodynamics, and its impact on aGVHD, infection, relapse, and transplantation-related mortality (TRM) were assessed. All patients received the planned abatacept doses, and no infusion reactions were noted. Compared with a cohort of patients not receiving abatacept (the StdRx cohort), patients enrolled in the study (the ABA cohort) demonstrated significant inhibition of early CD4(+) T cell proliferation and activation, affecting predominantly the effector memory (Tem) subpopulation, with 7- and 10-fold fewer proliferating and activated CD4(+) Tem cells, respectively, at day+28 in the ABA cohort compared with the StdRx cohort (P < .01). The ABA patients demonstrated a low rate of aGVHD, despite robust immune reconstitution, with 2 of 10 patients diagnosed with grade II-IV aGVHD before day +100, no deaths from infection, no day +100 TRM, and with 7 of 10 evaluable patients surviving (median follow-up, 16 months). These results suggest that costimulation blockade with abatacept can significantly affect CD4(+) T cell proliferation and activation post-transplantation, and may be an important adjunct to standard immunoprophylaxis for aGVHD in patients undergoing unrelated-donor HCT.