A mutation in SLC37A4 causes a dominantly inherited congenital disorder of glycosylation characterized by liver dysfunction.

SLC37A4 encodes an endoplasmic reticulum (ER)-localized multitransmembrane protein required for transporting glucose-6-phosphate (Glc-6P) into the ER. Once transported into the ER, Glc-6P is subsequently hydrolyzed by tissue-specific phosphatases to glucose and inorganic phosphate during times of glucose depletion. Pathogenic variants in SLC37A4 cause an established recessive disorder known as glycogen storage disorder 1b characterized by liver and kidney dysfunction with neutropenia. We report seven individuals who presented with liver dysfunction multifactorial coagulation deficiency and cardiac issues and were heterozygous for the same variant, c.1267C>T (p.Arg423∗), in SLC37A4; the affected individuals were from four unrelated families. Serum samples from affected individuals showed profound accumulation of both high mannose and hybrid type N-glycans, while N-glycans in fibroblasts and undifferentiated iPSC were normal. Due to the liver-specific nature of this disorder, we generated a CRISPR base-edited hepatoma cell line harboring the c.1267C>T (p.Arg423∗) variant. These cells replicated the secreted abnormalities seen in serum N-glycosylation, and a portion of the mutant protein appears to relocate to a distinct, non-Golgi compartment, possibly ER exit sites. These cells also show a gene dosage-dependent alteration in the Golgi morphology and reduced intraluminal pH that may account for the altered glycosylation. In summary, we identify a recurrent mutation in SLC37A4 that causes a dominantly inherited congenital disorder of glycosylation characterized by coagulopathy and liver dysfunction with abnormal serum N-glycans.

Health status, emergency department visits, and oncologists' feedback: An analysis of secondary endpoints from a randomized phase II geriatric assessment trial.

PURPOSE: Geriatric Assessment (GA) can help uncover previously unknown health issues and recommend tailored interventions to optimize outcomes; however, no completed randomized trial has examined the impact of GA on utility-based health status, healthcare use, and oncologists' opinions about GA. We examined these secondary outcomes of a randomized phase II trial. METHODS: A planned analysis of secondary outcomes of a two-group parallel single-blind randomized phase II trial of GA (ClinicalTrials.gov Identifier:NCT02222259) recruited patients ≥ age 70, diagnosed with stage II-IV breast/gastrointestinal/genitourinary cancer within six weeks of beginning chemotherapy at the Princess Margaret Cancer Centre, Toronto, Canada. Descriptive analyses using intent-to-treat were conducted for health status (EuroQol EQ-5D-3L) and healthcare utilization (patient self-report). Oncologist opinions were captured via open-ended interviews and summarized. RESULTS: A total of 95 patients who met the inclusion criteria were approached; 61 of them consented (64%). For health status, at all time-points, there were no significant differences between the two groups. The number of emergency department and family physician visits was low overall; there were no statistically significant differences between the two groups at any time point. All interviewed oncologists (eight of fourteen invited) were satisfied with the intervention, but wanted more straightforward recommendations and earlier GA results. CONCLUSIONS: No difference was found in terms of relationships between GA and utility-based health status or GA and healthcare use. Underreporting of healthcare use was possible. Oncologists welcome GA feedback and prefer to receive it in pre-treatment decision context. Larger trials with earlier GA are warranted.

A randomized phase II trial of geriatric assessment and management for older cancer patients.

PURPOSE: Geriatric assessment and management (GAM) can identify current health issues and recommend interventions to optimize well-being of older adults, but no randomized trial has yet been completed in oncology. Therefore, a randomized phase 2 trial was conducted. METHODS: A two-group parallel single-blinded randomized phase II trial ( ClinicalTrials.gov Identifier: NCT02222259) enrolled patients aged ≥70 years, diagnosed with stage 2-4 gastrointestinal, genitourinary, or breast cancer within 6 weeks of commencing chemotherapy at Princess Margaret Cancer Centre. The coprimary feasibility outcomes were the proportion of eligible patients enrolled and retained. The coprimary clinical outcomes were quality of life (QOL) (EORTC QLQ C30) and modification of cancer treatment. Descriptive and regression analyses using intent-to-treat analysis were conducted. RESULTS: Sixty-one persons (64%) agreed to participate (31 allocated to intervention arm and 30 to control group). In the control group, more participants died and refused follow-up. The benefit of intervention over control on QOL at 3 months was greater for those who survived 6 months (difference 9.28; 95% CI -10.35 to 28.91) versus those who survived only 3 months (difference 6.55; 95% CI -9.63 to 22.73). CONCLUSIONS: This trial showed that it was feasible to recruit and retain older adults for a GAM study. Those who survived at least 6 months seemed to receive a greater QOL benefit than those who died or withdrew.

Chemotherapy treatment decision-making experiences of older adults with cancer, their family members, oncologists and family physicians: a mixed methods study.

PURPOSE: Although comorbidities, frailty, and functional impairment are common in older adults (OA) with cancer, little is known about how these factors are considered during the treatment decision-making process by OAs, their families, and health care providers. Our aim was to better understand the treatment decision process from all these perspectives. METHODS: A mixed methods multi-perspective longitudinal study using semi-structured interviews and surveys with 29 OAs aged ≥70 years with advanced prostate, breast, colorectal, or lung cancer, 24 of their family members,13 oncologists, and 15 family physicians was conducted. The sample was stratified on age (70-79 and 80+). All interviews were analyzed using thematic analysis. RESULTS: There was no difference in the treatment decision-making experience based on age. Most OAs felt that they should have the final say in the treatment decision, but strongly valued their oncologists' opinion. "Trust in my oncologist" and "chemotherapy as the last resort to prolong life" were the most important reasons to accept treatment. Families indicated a need to improve communication between them, the patient and the specialist, particularly around goals of treatment. Comorbidity and potential side-effects did not play a major role in the treatment decision-making for patients, families, or oncologists. Family physicians reported no involvement in decisions but desired to be more involved. CONCLUSION: This first study using multiple perspectives showed neither frailty nor comorbidity played a role in the treatment decision-making process. Efforts to improve communication were identified as an opportunity that may enhance quality of care. In a mixed methods study multiple perspective study with older adults with cancer, their family members, their oncologist and their family physician we explored the treatment decision making process and found that most older adults were satisfied with their decision. Comorbidity, functional status and frailty did not impact the older adult's or their family members' decision.

ST8SIA4-Dependent Polysialylation is Part of a Developmental Program Required for Germ Layer Formation from Human Pluripotent Stem Cells.

Polysialic acid (PSA) is a carbohydrate polymer of repeating α-2,8 sialic acid residues that decorates multiple targets, including neural cell adhesion molecule (NCAM). PST and STX encode the two enzymes responsible for PSA modification of target proteins in mammalian cells, but despite widespread polysialylation in embryonic development, the majority of studies have focused strictly on the role of PSA in neurogenesis. Using human pluripotent stem cells (hPSCs), we have revisited the developmental role of PST and STX and show that early progenitors of the three embryonic germ layers are polysialylated on their cell surface. Changes in polysialylation can be attributed to lineage-specific expression of polysialyltransferase genes; PST is elevated in endoderm and mesoderm, while STX is elevated in ectoderm. In hPSCs, PST and STX genes are epigenetically marked by overlapping domains of H3K27 and H3K4 trimethylation, indicating that they are held in a "developmentally-primed" state. Activation of PST transcription during early mesendoderm differentiation is under control of the T-Goosecoid transcription factor network, a key regulatory axis required for early cell fate decisions in the vertebrate embryo. This establishes polysialyltransferase genes as part of a developmental program associated with germ layer establishment. Finally, we show by shRNA knockdown and CRISPR-Cas9 genome editing that PST-dependent cell surface polysialylation is essential for endoderm specification. This is the first report to demonstrate a role for a glycosyltransferase in hPSC lineage specification. Stem Cells 2016;34:1742-1752.

Replication timing: a fingerprint for cell identity and pluripotency.

Many types of epigenetic profiling have been used to classify stem cells, stages of cellular differentiation, and cancer subtypes. Existing methods focus on local chromatin features such as DNA methylation and histone modifications that require extensive analysis for genome-wide coverage. Replication timing has emerged as a highly stable cell type-specific epigenetic feature that is regulated at the megabase-level and is easily and comprehensively analyzed genome-wide. Here, we describe a cell classification method using 67 individual replication profiles from 34 mouse and human cell lines and stem cell-derived tissues, including new data for mesendoderm, definitive endoderm, mesoderm and smooth muscle. Using a Monte-Carlo approach for selecting features of replication profiles conserved in each cell type, we identify "replication timing fingerprints" unique to each cell type and apply a k nearest neighbor approach to predict known and unknown cell types. Our method correctly classifies 67/67 independent replication-timing profiles, including those derived from closely related intermediate stages. We also apply this method to derive fingerprints for pluripotency in human and mouse cells. Interestingly, the mouse pluripotency fingerprint overlaps almost completely with previously identified genomic segments that switch from early to late replication as pluripotency is lost. Thereafter, replication timing and transcription within these regions become difficult to reprogram back to pluripotency, suggesting these regions highlight an epigenetic barrier to reprogramming. In addition, the major histone cluster Hist1 consistently becomes later replicating in committed cell types, and several histone H1 genes in this cluster are downregulated during differentiation, suggesting a possible instrument for the chromatin compaction observed during differentiation. Finally, we demonstrate that unknown samples can be classified independently using site-specific PCR against fingerprint regions. In sum, replication fingerprints provide a comprehensive means for cell characterization and are a promising tool for identifying regions with cell type-specific organization.

Human hepatic stem cells from fetal and postnatal donors.

Human hepatic stem cells (hHpSCs), which are pluripotent precursors of hepatoblasts and thence of hepatocytic and biliary epithelia, are located in ductal plates in fetal livers and in Canals of Hering in adult livers. They can be isolated by immunoselection for epithelial cell adhesion molecule-positive (EpCAM+) cells, and they constitute approximately 0.5-2.5% of liver parenchyma of all donor ages. The self-renewal capacity of hHpSCs is indicated by phenotypic stability after expansion for >150 population doublings in a serum-free, defined medium and with a doubling time of approximately 36 h. Survival and proliferation of hHpSCs require paracrine signaling by hepatic stellate cells and/or angioblasts that coisolate with them. The hHpSCs are approximately 9 microm in diameter, express cytokeratins 8, 18, and 19, CD133/1, telomerase, CD44H, claudin 3, and albumin (weakly). They are negative for alpha-fetoprotein (AFP), intercellular adhesion molecule (ICAM) 1, and for markers of adult liver cells (cytochrome P450s), hemopoietic cells (CD45), and mesenchymal cells (vascular endothelial growth factor receptor and desmin). If transferred to STO feeders, hHpSCs give rise to hepatoblasts, which are recognizable by cordlike colony morphology and up-regulation of AFP, P4503A7, and ICAM1. Transplantation of freshly isolated EpCAM+ cells or of hHpSCs expanded in culture into NOD/SCID mice results in mature liver tissue expressing human-specific proteins. The hHpSCs are candidates for liver cell therapies.