Project description:We have compared the proteome, transcriptome and metabolome of two isogenic cell lines: MCF-10A, derived from human breast epithelium, and the mutant MCF-10A-H1047R. These cell lines differ by a single amino acid substitution (H1047R) caused by single nucleotide change in one allele of the PIK3CA gene which encodes the catalytic subunit p110α of phosphatidylinositol 3-kinase (PI3K). The H1047R mutation of PIK3CA is one of the most frequently encountered somatic cancer-specific mutations. In MCF-10A, this mutation induces an extensive cellular reorganization that far exceeds the known signaling activities of PI3K. The changes are highly diverse; with examples in structural protein levels, the DNA repair machinery and sterol synthesis. Gene set enrichment analysis reveals a highly significant concordance of the genes differentially expressed in MCF-10A-H1047R cells and the established protein and RNA signatures of basal breast cancer. No such concordance was found with the specific gene signatures of other histological types of breast cancer. Our data document the power of a single base mutation, inducing an extensive remodeling of the cell toward the phenotype of a specific cancer. 2 cell lines (H1047R and WT), 4 time points (0, 6, 12, 24 hours), 3 replicates
Project description:We have compared the proteome, transcriptome and metabolome of two isogenic cell lines: MCF-10A, derived from human breast epithelium, and the mutant MCF-10A-H1047R. These cell lines differ by a single amino acid substitution (H1047R) caused by single nucleotide change in one allele of the PIK3CA gene which encodes the catalytic subunit p110α of phosphatidylinositol 3-kinase (PI3K). The H1047R mutation of PIK3CA is one of the most frequently encountered somatic cancer-specific mutations. In MCF-10A, this mutation induces an extensive cellular reorganization that far exceeds the known signaling activities of PI3K. The changes are highly diverse; with examples in structural protein levels, the DNA repair machinery and sterol synthesis. Gene set enrichment analysis reveals a highly significant concordance of the genes differentially expressed in MCF-10A-H1047R cells and the established protein and RNA signatures of basal breast cancer. No such concordance was found with the specific gene signatures of other histological types of breast cancer. Our data document the power of a single base mutation, inducing an extensive remodeling of the cell toward the phenotype of a specific cancer.
Project description:We used CRISPR/Cas9 to knock in the cancer "hotspot" mutation PIK3CA-H1047R into one or both alleles of a wild-type induced pluripotent stem cell (iPSC) line (WTC11; Coriell # GM25256; P37-P38). Four cultures from each genotype (3 wild-type clones, 3 heterozygous clones, 2 homozygous clones) were subjected to paired-end mRNA sequencing (mean read length = 150 bp). The aim of this experiment was to confirm and expand upon previous transcriptomic results suggesting a near-binary transcriptional effect in homozygous versus heterozygous PIK3CA-H1047R iPSCs (publication doi: 10.1073/pnas.1821093116). According to the high-depth transcriptomic dataset, PIK3CA-H1047R/H1047R iPSCs exhibited altered expression of 5644 genes, whereas heterozygous hPSCs showed 492 differentially-expressed genes, supporting a nearly deterministic phenotypic effect of homozygosity for PIK3CA-H1047R. The differential gene expression analyses were performed based on the limma/voom/eBayes framework (doi: 10.1093/nar/gkv007), using customised scripts with FDR < 0.05 and absolute log2(fold-change) cut-off >= 1.3.
Project description:MCF10A cells: control vs. PIK3CA mutant (H1047R) Transcriptional profiling of MCF10A comparing control (expressing JP1520-PIK3CA-WT; Addgen plasmid #14570) and PIK3CA mutant (JP1520-PIK3CA-H1047R; Addgene plasmic#14572). Goal was to determine the effects of the PIK3CA H1047R mutation in the on global gene expression in MCF10A cells.
Project description:We used CRISPR/Cas9 to knock in the cancer "hotspot" mutation PIK3CA-H1047R into one or both alleles of a wild-type induced pluripotent stem cell (iPSC) line (WTC11; Coriell # GM25256; P37-P38). Three clones from each genotype (wild-type, heterozygous, homozygous) were subjected to single-end mRNA sequencing (mean read depth per sample: 20 million) to determine whether PIK3CA-H1047R exerts allele dose-dependent transcriptional effects. Multidimensional scaling demonstrated distinct transcriptomic signatures of wild-type, heterozygous and homozygous cells. The transcriptome of heterozygous cells was nearly identical to wild-type controls, with only 131 differentially-expressed transcripts (FDR = 0.05). In contrast, homozygosity for PIK3CA-H1047R led to differential expression of 1,914 genes. This indicates widespread transcriptional remodeling with a sharp allele dose-dependency, suggestive of a threshold effect.
Project description:This study examined the effect of mutant PIK3CAH1047R expression in mammary subsets of preneoplastic mammary glands from Lgr5-creERT2/PIK3CA H1047R mice Mammary cell subpopulations were isolated from Lgr5-creERT2/PIK3CA H1047R and Lgr5-creERT2 control animals 4 weeks after activation of PIK3CA H1047R transgene expression by Tamoxifen injection. Pooled mammary glands of 2-3 estrus-synchronized mice per genotype were sorted in 3 independent sortings and used for microarray analysis (24 samples in total).
Project description:Breast cancer is the most frequent cancer in women and consists of heterogeneous types of tumours that are classified into different histological and molecular subtypes1-3. Pik3ca and p53 are the two most frequently mutated genes and are associated with different types of human breast cancers4. The cellular origin and the mechanisms leading to Pik3ca-induced tumour heterogeneity remain unknown. Here, we used a genetic approach in mice to define the cellular origin of Pik3ca-derived tumours and its impact on tumour heterogeneity. Surprisingly, oncogenic Pik3ca-H1047R expression at physiological levels5 in basal cells (BCs) using K5CREERT2 induced the formation of luminal ER+PR+ tumours, while its expression in luminal cells (LCs) using K8CREERT2 gave rise to luminal ER+PR+ tumours or basal-like ER-PR- tumours. Concomitant deletion of p53 and expression of Pik3ca-H1047R accelerated tumour development and induced more aggressive mammary tumours. Interestingly, expression of Pik3ca-H1047R in unipotent BCs gave rise to luminal-like cells, while its expression in unipotent LCs gave rise to basal-like cells before progressing into invasive tumours. Transcriptional profiling of cells that have undergone cell fate transition upon Pik3ca-H1047R expression in unipotent progenitors demonstrate a profound oncogene-induced reprogramming of these newly formed cells and identified gene signatures, characteristic of the different cell fate switches that occur upon Pik3ca-H1047R expression in BC and LCs, which correlated with the cell of origin, tumour type and different clinical outcomes. Altogether our study identifies the cellular origin of Pik3ca-induced tumours and reveals that oncogenic Pik3ca-H1047R activates a multipotent genetic program in normally lineage-restricted populations at the early stage of tumour initiation, setting the stage for future intratumoural heterogeneity. These results have important implications for our understanding of the mechanisms controlling tumour heterogeneity and the development of new strategies to block PIK3CA breast cancer initiation. Luminal and basal cells, or tumour cells, from mice in which expression of PIK3CA-H1047R and YFP (and in some conditions loss of p53) was targeted in basal cells using K5CREERT2 or in luminal cells using K8CREERT2 were FACS isolated and RNA was extracted before being hybridized Affymetrix microarrays.