Project description:<p>Due to the paucity of patient derived models in rare cancers, identification of therapeutic targets remains challenging. We developed a patient derived model, CLF-PED-015-T, from a patient with an undifferentiated sarcoma. From this model, we performed pooled RNAi and CRISPR-Cas9 negative selection screens and integrated that with a small molecule screen. Integration of these data identified CDK4 and XPO1 as potential therapeutic targets.</p>
| phs001121 | dbGaP
Project description:Scalable pooled CRISPR screens with single cell chromatin accessibility profiling.
Project description:CRISPR knockout screens have accelerated the discovery of important cancer genetic dependencies. However, traditional CRISPR-Cas9 screens are limited in their ability to assay the function of redundant or duplicated genes. Paralogs in multi-gene families constitute two-thirds of the protein-coding genome, so this blind spot is the rule, not the exception. To overcome the limitations of single gene CRISPR knockout screens, we developed paired guide RNAs for Paralog gENetic interaction mapping (pgPEN), a pooled CRISPR/Cas9 approach which targets over a thousand duplicated human paralogs in single knockout and double knockout configurations. We applied pgPEN to two cell lineages and discovered that over 10% of human paralogs exhibit synthetic lethality in at least one cellular context. We recovered known synthetic lethal paralogs such as MAP2K1/MAP2K2, important drug targets such as CDK4/CDK6, and numerous other synthetic lethal pairs such as CCNL1/CCNL2. In addition, we identified ten tumor suppressive paralog pairs whose compound loss promotes cell growth. These findings identify a large number of previously unidentified essential gene families and nominate new druggable targets for oncology drug discovery.
Project description:H1-HeLa cells were stably transduced with lentiCas9-Blast (Addgene, Plasmid #52962) and subsequently selected using blasticidin to generate constitutively expressing Cas9 H1-HeLa cells. A single Cas9-expressing H1-HeLa clone was then transduced with lentivirus without a selection marker to stably express CDHR3 C529Y (H1-HeLa+CDHR3). A single CDHR3-expressing H1-HeLa clone was then chosen based on RT-qPCR of CHDR3 expression and RV-C15 RNA levels for mutagenesis. 300 million of the H1-HeLa cells constitutively expressing CDHR3 and Cas9 were transduced with the lentiGuide-Puro from the GeCKO v2 library at a MOI of 0.3. Cells were selected using puromycin and heterogeneous H1-HeLa knockout cell populations were subsequently pooled together. The CRISPR genetic screens were started 10 days post transduction. >1000-fold coverage of mutagenized cells (libraries A and B) was infected with either RV-C15 (MOI=1 PFU/cell) or EV-D68 Missouri (MOI=1 PFU/cell). RV-C15 infection was repeated for an additional round at 6 days post-infection. As soon as appearance of visibly viable colonies was observed, populations of virus-resistant cells were pooled and harvested. Uninfected starting populations of mutagenized cells were used as the unselected reference. Total genomic DNA from both virus-resistant and uninfected cells was respectively extracted using QIAamp DNA Mini Kit (Qiagen). The inserted guide RNA sequences were retrieved from the genomic DNA by PCR amplification. The PCR products were then purified and subjected to NextSeq platform (Illumina) next-generation sequencing.
Project description:A human tissue screen identifies a regulator of ER secretion as a brain size determinant. Abstract: Loss-of-function (LOF) screens provide a powerful approach to identify regulators in biological processes. Pioneered in laboratory animals, LOF screens of human genes are currently restricted to two-dimensional (2D) cell culture hindering testing of gene functions requiring tissue context. Here we present CRISPR-LIneage tracing at Cellular resolution in Heterogenous Tissue (CRISPR-LICHT), enabling parallel LOF studies in human cerebral organoid tissue. We used CRISPR-LICHT to test 173 microcephaly candidate genes revealing 25 to be involved in known and uncharacterized microcephaly-associated pathways. We characterized Immediate Early Response 3 Interacting Protein 1 (IER3IP1) regulating the unfolded protein response (UPR) and extracellular matrix (ECM) protein secretion crucial for tissue integrity, with dysregulation resulting in microcephaly. Our human tissue screening technology identifies microcephaly genes and mechanisms involved in brain size control.
Project description:Induced pluripotent stem cell (iPSC) derived organoid systems provide models to study human organ development. Single-cell transcriptome sequencing enables highly-resolved descriptions of cell state heterogeneity within these systems and computational methods can reconstruct developmental trajectories. However, new approaches are needed to directly measure lineage relationships in these systems. Here we establish an inducible dual channel lineage recorder, iTracer, that couples reporter barcodes, inducible CRISPR/Cas9 scarring, and single-cell transcriptomics to analyze state and lineage relationships in iPSC-derived systems. This data set include the iTracer data of 12 cerebral organoids.