Gene expression signatures associated with sensitivity to azacitidine in myelodysplastic syndromes.

Allogeneic stem cell transplantation is currently the only curative treatment option for myelodysplastic syndromes (MDS). Pre-transplant debulking treatment have been employed for advanced MDS and we previously reported that marrow response (blast ≤ 5%) following the bridging therapy with hypomethylating agent was an independent favorable factor for survival; however, it is still not clear which patients will respond to hypomethylating agent and which genomic features can predict the response. In this study, we performed RNAseq for 23 MDS patients among which 14 (61%) and 9 (39%) patients showed marrow complete remission and primary resistance to azacitidine, respectively. Differential expression-based analyses of treatment-naive, baseline gene expression profiles revealed that molecular functions representing mitochondria and apoptosis were up-regulated in responders. In contrast, we identified genes involved in the Wnt pathway were relatively up-regulated in non-responders. In independent validation cohorts of MDS patients, the expression of gene sets specific to non-responders and responders distinguished the patients with favorable prognosis and those responded to azacitidine highlighting the prognostic and predictive implication. In addition, a systems biology approach identified genes involved in ubiquitination, such as UBC and PFDN2, which may be key players in the regulation of differential gene expression in treatment responders and non-responders. Taken together, identifying the gene expression signature may advance our understanding of the molecular mechanisms of azacitidine and may also serve to predict patient responses to drug treatment.

Correction to: Graft immaturity and safety concerns in transplanted human kidney organoids.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Graft immaturity and safety concerns in transplanted human kidney organoids.

For chronic kidney disease, regeneration of lost nephrons with human kidney organoids derived from induced pluripotent stem (iPS) cells is proposed to be an attractive potential therapeutic option. It remains unclear, however, whether organoids transplanted into kidneys in vivo would be safe or functional. Here, we purified kidney organoids and transplanted them beneath the kidney capsules of immunodeficient mice to test their safety and maturity. Kidney organoid grafts survived for months after transplantation and became vascularized from host mouse endothelial cells. Nephron-like structures in grafts appeared more mature than kidney organoids in vitro, but remained immature compared with the neighboring mouse kidney tissue. Ultrastructural analysis revealed filtration barrier-like structures, capillary lumens, and tubules with brush border in the transplanted kidney organoids, which were more mature than those of the kidney organoids in vitro but not as organized as adult mammalian kidneys. Immaturity was a common feature of three separate differentiation protocols by immunofluorescence analysis and single cell RNA sequencing. Stroma of transplanted kidney organoid grafts were filled with vimentin-positive mesenchymal cells, and chondrogenesis, cystogenesis, and stromal expansion were observed in the long term. Transcription profiles showed that long-term maintenance after kidney organoid transplantation induced transcriptomic reprogramming with prominent suppression of cell-cycle-related genes and upregulation of extracellular matrix organization. Our data suggest that kidney organoids derived from iPS cells may be transplantable but strategies to improve nephron differentiation and purity are required before they can be applied in humans as a therapeutic option.

Immune Gene Signature Delineates a Subclass of Papillary Thyroid Cancer with Unfavorable Clinical Outcomes.

Papillary thyroid carcinoma (PTC) represents a heterogeneous disease with diverse clinical outcomes highlighting a need to identify robust biomarkers with clinical relevance. We applied non-negative matrix factorization-based deconvolution to publicly available gene expression profiles of thyroid cancers in the Cancer Genome Atlas (TCGA) consortium. Among three metagene signatures identified, two signatures were enriched in canonical BRAF-like and RAS-like thyroid cancers with up-regulation of genes involved in oxidative phosphorylation and cell adhesions, respectively. The third metagene signature representing up-regulation of immune-related genes further segregated BRAF-like and RAS-like PTCs into their respective subgroups of immunoreactive (IR) and immunodeficient (ID), respectively. BRAF-IR PTCs showed enrichment of tumor infiltrating immune cells, tall cell variant PTC, and shorter recurrence-free survival compared to BRAF-ID PTCs. RAS-IR and RAS-ID PTC subtypes included majority of normal thyroid tissues and follicular variant PTC, respectively. Immunopathological features of PTC subtypes such as immune cell fraction, repertoire of T cell receptors, cytolytic activity, and expression level of immune checkpoints such as and PD-L1 and CTLA-4 were consistently observed in two different cohorts. Taken together, an immune-related metagene signature can classify PTCs into four molecular subtypes, featuring the distinct histologic type, genetic and transcriptional alterations, and potential clinical significance.