Cancer genome characterization efforts now provide an initial view of the somatic alterations in primary tumors. However, most point mutations occur at low frequency. and the function of these alleles remain undefined. We have developed a scalable systematic approach to interrogate the function of cancer-associated gene variants. We subjected 474 mutant alleles curated from 5,338 tumors to pooled in vivo tumor formation assays and gene expression profiling. We identified 12 transforming alleles including two in genes (PIK3CB, POT1) that have not been shown to be tumorigenic. One rare KRAS allele, D33E, displayed tumorigenicity and constitutive activation of known RAS effector pathways. By comparing gene expression changes induced upon expression of wild type and mutant alleles, we inferred the activity of specific alleles. Since alleles found to be mutated only once in 5,338 tumors rendered cells tumorigenic, these observations underscore the value of integrating genomic information with functional studies.

Intravenous MSC administration is feasible and has a good short-term safety profile in patients with moderately severe IPF.

The PI3K pathway is frequently activated in cancer; therefore, considerable effort is focused on identifying compounds that can inhibit specific pathway components, particularly the hallmark oncogene PIK3CA. Although targeted inhibition of a cancer survival gene holds significant promise, there are concerns that drug resistance may emerge within the cancerous cells, thus limiting clinical efficacy. Using genetically defined human mammary epithelial cells, we evolved resistance to the PI3K/mammalian target of rapamycin (mTOR) inhibitor BEZ235, and by genome-wide copy number analyses, we identified MYC and eIF4E amplification within the resistant cells. Importantly, either MYC or eukaryotic translation initiation factor 4E (eIF4E) was required to bypass pharmacological PI3K/mTOR inhibition in resistant cells. Furthermore, these cells displayed elevated 5′ cap-dependent protein translation. Collectively, these findings suggest that analysis of drivers of protein translation could facilitate the identification of cancer lesions that confer resistance to PI3K pathway-targeted drugs.

SummaryMesenchymal stem cells (MSC) are being used increasingly in clinical trials for a range of regenerative and inflammatory diseases. Bone marrow is the traditional source but is relatively inaccessible in large volume. MSC have now been derived from tissues other than bone marrow including placenta and adipose tissue. We have used placenta obtained after delivery as a source of MSC and have been unable to detect any marked differences from marrow-derived MSC in terms of cell surface phenotype, chemokine receptor display, mesodermal differentiation capacity or immunosuppressive ability. This report described our manufacturing process for isolating and expanding placenta-derived human MSC and their safe infusion into the first patient in a clinical trial program of human placenta-derived MSC.