Project description:Whole Genome Sequencing of the murine breast cancer cell line 4T1 and of the murine melanoma cell line B16-ova was carried out with the aim of identifying somatic mutations. We also ran deep Mass Spectrometry proteomics analysis on the same cell lines, aiming to determine which somatic mutations carry over to the protein expression level. Further, we tested these cancer specific protein epitopes (putative neoantigens) for immunogenicity using mouse models. Finally, the putative neoantigens that showed good immunogenic potential were used in tumor growth control experiments with mice engrafted with the two tumor cell lines. In these experiments we tested whether cancer vaccines based on individual neoantigen peptides (MHC-I) restricted the growth of the tumor compared to adequate controls. The overall aim of the project is to validate the ability of our multi-omics/bioinformatics pipeline to identify and deliver neoantigens that can be used to suppress tumor growth. File names Sample names P10859_101_S1_L001_R1_001_BHKWV3CCXY 4T1_S1_L001_R1_001_BHKWV3CCXY P10859_101_S1_L001_R2_001_BHKWV3CCXY 4T1_S1_L001_R2_001_BHKWV3CCXY P10859_101_S1_L002_R1_001_BHKWV3CCXY 4T1_S1_L002_R1_001_BHKWV3CCXY P10859_101_S1_L002_R2_001_BHKWV3CCXY 4T1_S1_L002_R2_001_BHKWV3CCXY P10859_102_S2_L003_R1_001_BHKWV3CCXY B16-OVA_S2_L003_R1_001_BHKWV3CCXY P10859_102_S2_L003_R2_001_BHKWV3CCXY B16-OVA_S2_L003_R2_001_BHKWV3CCXY P10859_102_S2_L004_R1_001_BHKWV3CCXY B16-OVA_S2_L004_R1_001_BHKWV3CCXY P10859_102_S2_L004_R2_001_BHKWV3CCXY B16-OVA_S2_L004_R2_001_BHKWV3CCXY
Project description:Here we report the discovery of truncating mutations of the gene encoding the cohesin subunit STAG2, which regulates sister chromatid cohesion and segregation, in 36% of papillary non-invasive urothelial carcinomas and 16% of invasive urothelial carcinomas of the bladder. Our studies suggest that STAG2 has a role in controlling chromosome number but not the proliferation of bladder cancer cells. These findings identify STAG2 as one of the most commonly mutated genes in bladder cancer. Affymetrix CytoScan HD Arrays were performed according to the manufacturer's directions on genomic DNA extracted directly from 12 snap-frozen human urothelial carcinoma primary tumors with somatic mutations of the STAG2 gene.
Project description:Aneuploidy is among the most common hallmarks of cancer, yet the underlying genetic mechanisms are still poorly defined. We have recently identified STAG2 as a gene that is mutated in human cancer and whose inactivation leads directly to chromosomal instability and aneuploidy. However, no single tumor type has yet been identified in which inactivation of a cohesin subunit represents a predominant mutational event. Here we used immunohistochemistry to screen a panel of 2,214 tumors from each of the major human tumor types to identify additional tumor types harboring somatic loss of STAG2. Strikingly, STAG2 expression was completely absent in 18% of urothelial carcinomas, the most common type of bladder cancer and the fifth most common cancer in the United States. DNA sequencing revealed that somatic mutations of STAG2 were present in 21% of urothelial carcinomas, which were found to be a group of highly aneuploid tumors. The acquisition of STAG2 mutations was shown to be an early event in the pathogenesis of urothelial carcinoma. STAG2 loss was significantly associated with lymph node invasion, increased disease recurrence, and reduced cancer-specific survival. These results identify STAG2 as one of the most commonly mutated genes in bladder cancer discovered to date, and demonstrate that STAG2 inactivation defines an aggressive subtype of bladder cancer with particularly poor prognosis. Affymetrix CytoScan HD Arrays were performed according to the manufacturer's directions on genomic DNA extracted directly from snap-frozen human urothelial carcinoma primary tumors. Copy number analysis using Affymetrix CytoScan HD Arrays was performed for 12 human urothelial carcinomas of the bladder with truncating mutations of the STAG2 gene.
Project description:Cancer genome sequencing consortiums have recently catalogued an abundance of somatic mutations in the chromatin-modifying enzymes that regulate enhancer chromatin function across a wide range of human cancers. Defining the molecular mechanisms underlying the potential oncogenic function for these epigenetic mutations could serve as the basis for precision medicine approaches for cancer treatment. MLL4 (KMT2D) is a key histone lysine mono-methyltransferase within the COMplex of Proteins ASsociated with Set1 (COMPASS) family that regulates chromatin at enhancers, potentially functions as a tumor suppressor and is highly mutated in a large number of human cancers. We report that the mutations which cause MLL4 protein truncation also alter its subcellular localization, resulting in loss-of-function in the nucleus and gain-of-function in the cytoplasm. We demonstrate that isogenic correction of MLL4 truncation mutation rescues the aberrant localization phenotype and restores multiple MLL4 regulatory functions, including COMPASS integrity and stabilization, histone H3K4 mono-methylation, enhancer activation, and gene regulation. Moreover, isogenic correction diminishes the sensitivity of MLL4-mutated cancer cells to targeted metabolic inhibition. Using immunohistochemistry (IHC), we identified cytoplasmic MLL4 unique to the tissue of bladder cancer patients with MLL4 mutations. Using a preclinical carcinogen bladder cancer mouse model, we demonstrate that truncated, cytoplasmic MLL4 can be a biomarker for MLL4-mutated bladder cancers and predicts response to targeted metabolic inhibition therapy. We propose using the cytoplasmic MLL4 truncation phenotype as a prognostic marker in bladder cancer. We also highlight the broader potential for patient stratification based on MLL4 mutation status in MLL4 truncation diseases, including human cancers and Kabuki Syndrome.