Induced pluripotent stem cell (iPSC)-derived dopaminergic (DA) neurons are an expected source for cell-based therapies for Parkinson’s disease (PD). The regulatory criteria for the clinical application of these therapies, however, have not been established. Here we show the results of our pre-clinical study, in which we evaluate the safety and efficacy of dopaminergic progenitors (DAPs) derived from a clinical-grade human iPSC line. We confirm the characteristics of DAPs by in vitro analyses. We also verify that the DAP population include no residual undifferentiated iPSCs or early neural stem cells and have no genetic aberration in cancer-related genes. Furthermore, in vivo studies using immunodeficient mice reveal no tumorigenicity or toxicity of the cells. When the DAPs are transplanted into the striatum of 6-OHDA-lesioned rats, the animals show behavioral improvement. Based on these results, we started a clinical trial to treat PD patients in 2018.
Background
Genomic alterations in blood-derived circulating tumor DNA (ctDNA) from patients with non-small cell lung adenocarcinoma (NSCLC) were ascertained and correlated with clinical characteristics and therapeutic outcomes.
Methods and Findings
Comprehensive plasma ctDNA testing was performed in 88 consecutive patients; 34 also had tissue next generation sequencing; 29, other forms of genotyping; and 25 (28.4%) had no tissue molecular tests because of inadequate tissue or biopsy contraindications. Seventy-two patients (82%) had ≥ 1 ctDNA alteration(s); amongst these, 75% carried alteration(s) potentially actionable by FDA-approved (61.1%) or experimental drug(s) in clinical trials (additional 13.9%). The most frequent alterations were in TP53 (44.3% of patients), EGFR (27.3%), MET (14.8%), KRAS (13.6%), and ALK (6.8%) genes. The concordance rate for EGFR alterations was 80.8% (100% versus 61.5% (≤ 1 versus > 1 month between tests; P = 0.04)) for patients with any detectable ctDNA alterations. Twenty-five patients (28.4%) received therapy matching ≥ 1 ctDNA alteration(s); 72.3% (N=16/22) of the evaluable matched patients achieved stable disease ≥ 6 months (SD) or partial response (PR). Five patients with ctDNA-detected EGFR T790M were subsequently treated with a third generation EGFR inhibitor; all five achieved SD ≥ 6 months/PR. Patients with ≥ 1 alteration with ≥ 5% variant allele fraction (versus < 5%) had a significantly shorter median survival (P = 0.012).
Conclusions
ctDNA analysis detected alterations in the majority of patients, with potentially targetable aberrations found at expected frequencies. Therapy matched to ctDNA alterations demonstrated appreciable therapeutic efficacy, suggesting clinical utility that warrants future prospective studies.
Our results demonstrate that pre-RC formation regulates chromatin association of XEco2 in Xenopus egg extracts. We propose that this reaction is critical to acetylate cohesin, whose DNA binding is subsequently stabilized by DNA replication.
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