ABSTRACT
We have compared the proteome, transcriptome, and metabolome of two cell lines: the human breast epithelial line MCF-10A and its mutant descendant MCF-10A-H1047R. These cell lines are derived from the same parental stock and differ by a single amino acid substitution (H1047R) caused by a single nucleotide change in one allele of the PIK3CA gene, which encodes the catalytic subunit p110α of PI3K (phosphatidylinositol 3-kinase). They are considered isogenic. 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.
Subject(s)
Breast Neoplasms/genetics , Mutation, Missense , Neoplasm Proteins/genetics , Phosphatidylinositol 3-Kinases/genetics , RNA, Neoplasm/genetics , Amino Acid Substitution , Breast Neoplasms/enzymology , Breast Neoplasms/pathology , Cell Line, Tumor , Class I Phosphatidylinositol 3-Kinases , DNA Mutational Analysis/methods , DNA Repair/genetics , Female , Humans , Neoplasm Proteins/metabolism , Phosphatidylinositol 3-Kinases/metabolism , RNA, Neoplasm/metabolismABSTRACT
RATIONALE: Fluoxetine (Prozac®) is the most frequently prescribed drug to battle depression in pregnant women, but its safety in the unborn child has not yet been established. Fluoxetine, a selective serotonin reuptake inhibitor, crosses the placenta, leading to increased extracellular serotonin levels and potentially neurodevelopmental changes in the fetus. OBJECTIVES: The purpose of this study was to elucidate the long-term consequences of prenatal fluoxetine in rats. METHODS: Pregnant rats were injected daily with 12 mg/kg fluoxetine or vehicle from gestational day 11 until birth, and the behavior of the offspring was monitored. RESULTS: Plasma fluoxetine transfer from mother to pup was 83%, and high levels of fluoxetine (13.0 µg/g) were detected in the pup brain 5 h after the last injection. Fluoxetine-treated dams gave birth to litters 15% smaller than usual and to pups of reduced weight (until postnatal day 7). Furthermore, prenatal fluoxetine exposure significantly increased anxiety in the novelty-suppressed feeding test, the footshock-induced conditioned place aversion test, and the elevated plus maze test (following footshock pre-exposure) during adulthood, and also significantly decreased components of social play behavior at 4 weeks of age, and a strong tendency for increased self-grooming and making less contact in adults. Behavioral despair, anhedonia, and sexual behavior were not different between treatment groups. Finally, the hypothermic response to the 5-HT(1A) agonist flesinoxan was observed at a lower dose in prenatally fluoxetine-exposed rats than in controls. CONCLUSIONS: Prenatal fluoxetine exposure in rats leads to detrimental behavioral outcomes in later life, which may partly be due to altered 5-HT(1A) receptor signaling.
