Project description:Palb2 interacts with BRCA1 and BRCA2 in supercomplexes involved in DNA repair via homologous recombination. Heterozygous germline mutations in PALB2 confer a moderate risk of breast cancer while biallelic PALB2 mutations are linked to a severe form of Fanconi anaemia characterized by early childhood solid tumours and severe chromosomal instability. In contrast to BRCA1- or BRCA2-associated cancers, breast tumours in heterozygous PALB2 mutation carriers do not show loss of the wild type allele, suggesting PALB2 might be haploinsufficient for tumour suppression. To study the role of PALB2 in development and tumourigenesis, we have generated Palb2GT mouse mutants using a gene trap approach. Whereas Palb2GT/GT homozygous mutant embryos died at mid-gestation due to massive apoptosis, Palb2GT/+ heterozygous mice were viable and did not show any obvious abnormalities. Deletion of p53 alleviated the phenotype of Palb2GT/GT embryos, but did not rescue embryonic lethality. In addition, loss of p53 did not significantly collaborate with Palb2 heterozygosity in tumourigenesis in heterozygous or homozygous p53 knockout mice. Tumours arising in Palb2GT/+;p53+/– or Palb2GT/+;p53–/– compound mutant mice retained the wild type Palb2 allele and did not display increased genomic instability. Comparison of 15 Palb2GT/+;p53-/- and 11 Palb2+/+;p53-/- lymphomas. Spleen/liver DNA of the same animal was used as reference material.
Project description:Palb2 interacts with BRCA1 and BRCA2 in supercomplexes involved in DNA repair via homologous recombination. Heterozygous germline mutations in PALB2 confer a moderate risk of breast cancer while biallelic PALB2 mutations are linked to a severe form of Fanconi anaemia characterized by early childhood solid tumours and severe chromosomal instability. In contrast to BRCA1- or BRCA2-associated cancers, breast tumours in heterozygous PALB2 mutation carriers do not show loss of the wild type allele, suggesting PALB2 might be haploinsufficient for tumour suppression. To study the role of PALB2 in development and tumourigenesis, we have generated Palb2GT mouse mutants using a gene trap approach. Whereas Palb2GT/GT homozygous mutant embryos died at mid-gestation due to massive apoptosis, Palb2GT/+ heterozygous mice were viable and did not show any obvious abnormalities. Deletion of p53 alleviated the phenotype of Palb2GT/GT embryos, but did not rescue embryonic lethality. In addition, loss of p53 did not significantly collaborate with Palb2 heterozygosity in tumourigenesis in heterozygous or homozygous p53 knockout mice. Tumours arising in Palb2GT/+;p53+/– or Palb2GT/+;p53–/– compound mutant mice retained the wild type Palb2 allele and did not display increased genomic instability.
2011-01-21 | GSE26723 | GEO
Project description:A case report of a mucinous breast carcinoma patient
Project description:Lung cancer is the leading cause of cancer death both in men and women. Tumor heterogeneity is an impediment to targeted treatment of all cancers, including lung cancer. Here, we sought to characterize changes in tumor proteome and phosphoproteome by longitudinal, prospective collection of tumor tissue of an exceptional responder lung adenocarcinoma patient who survived with metastatic lung adenocarcinoma for more than seven years with HER2-directed therapy in combination with chemotherapy. We employed “Super-SILAC” and TMT labeling strategies to quantify the proteome and phosphoproteome of a lung metastatic site and ten different metastatic progressive lymph nodes collected across a span of seven years, including five lymph nodes procured at autopsy. We identified specific signaling networks enriched in lung compared to the lymph node metastatic sites. We correlated the changes in protein abundance with changes in copy number alteration (CNA) and transcript expression. To further interrogate the mass spectrometry data, patient-specific database was built incorporating all the somatic variants identified by whole genome sequencing (WGS) of genomic DNA from the lung, one lymph node metastatic site and blood. An extensive validation pipeline was built for confirmation of variant peptides. We validated 360 spectra corresponding to 55 germline and 6 somatic variant peptides. Targeted MRM assays demonstrated expression of two novel variant somatic peptides, CDK12 G879V and FASN-R1439Q, with expression in lung and lymph node metastatic sites, respectively. CDK12 G879V mutation likely results in a nonfunctional kinase and knockdown of CDK12 in lung adenocarcinoma cells increased chemotherapy sensitivity, explaining the complete resolution of the lung metastatic sites in this patient.
Project description:PARP inhibitor olaparib induces the formation of polyploid giant cancer cells (PGCCs) in ovarian and breast cancer cell lines, human high-grade serous ovarian cancer (HGSC)–derived organoids, and HGSC patient-derived xenografts (PDXs). Time-lapse tracking of ovarian cancer cells revealed that PGCCs primarily developed from endoreplication of cancer cells after exposure to sublethal concentrations of olaparib. PGCCs exhibited features of senescent cells but, after olaparib withdrawal, could escape senescence via restitutional multipolar endomitosis and other modes of cell division to generate mitotically competent resistant daughter cells. The contraceptive drug mifepristone blocked PGCC formation and daughter cell production. Mifepristone/olaparib combination therapy substantially reduced tumor growth in PDX models without previous olaparib exposure, while mifepristone alone decreased tumor growth in PDX models with acquired olaparib resistance. Thus, targeting PGCCs may represent a promising approach to potentiate the therapeutic response to PARPi and overcome PARPi-induced resistance.
Project description:The project contains raw and result files from a proteomic profiling of a male breast cancer (MBC) case. Label-free quantification-mass spectrometry (LFQ-MS) and bioinformatics analysis were employed to investigate the differentially expressed proteins (DEPs) among distinct tissue samples: the primary breast tumor, axillary metastatic lymph nodes and the adjacent non-tumor breast tissue. An additional proteomic comparative analysis was performed with a primary breast tumor of a female patient. A number of Ingenuity® Pathway Analysis (IPA) (QIAGEN Inc.) and functional annotation tools were used to further analyze the DEPs. Altogether, our findings revealed deregulated proteins into signaling pathways involved in the cancer development and provided a landscape of proteomic data for the MBC research.
Project description:Breast and ovarian cancer susceptibility genes, BRCA1 and PALB2 have enigmatic roles in cellular growth and mammalian development. While these genes are essential for growth during early developmental programs, inactivation later in adulthood leads to increased growth and formation of tumors, leading to their designation as tumor suppressors. We performed genome-wide analysis assessing their chromatin residence and gene expression responsiveness using high throughput sequencing in breast epithelial cells. These experiments revealed a critical role for BRCA1 and PALB2 in transcriptional responsiveness to NF-kB, a crucial mediator of growth and inflammatory response during development and cancer. Importantly, we also uncovered a vital role for these proteins in response to retinoic acid (RA), a growth inhibitory signal in breast cancer cells, which may constitute the basis for their tumor suppressor activity. Comparison of the genome wide profiles of the BRCA protein complex (BRCA1 and PALB2) and phosphorylated RNAPII (P-Ser2) in MCF10A cells by ChIP-seq. Effect of BRCA1 and PALB2 knockdown (shRNAs) on transcription was assessed by RNA-seq.
Project description:The majority of patients with late-stage breast cancer develop distal bone metastases. The bone microenvironment can affect response to therapy, and uncovering the underlying mechanisms could help identify improved strategies for treating bone metastatic breast cancer. Here, we observed that osteoclasts reduced the sensitivity of breast cancer cells to DNA damaging agents, including cisplatin and the PARP inhibitor (PARPi) olaparib. Metabolic profiling identified elevated glutamine production by osteoclasts. Glutamine supplementation enhanced the survival of breast cancer cells treated with DNA damaging agents, while blocking glutamine uptake increased sensitivity and suppressed bone metastasis. GPX4, the critical enzyme responsible for glutathione oxidation, was upregulated in cancer cells following PARPi treatment through stress-induced ATF4-dependent transcriptional programming. Increased glutamine uptake and GPX4 upregulation concertedly enhanced glutathione metabolism in cancer cells to help neutralize oxidative stress and generate PARPi resistance. Analysis of paired patient samples of primary breast tumors and bone metastases revealed significant induction of GPX4 in bone metastases. Combination therapy utilizing PARPi and zoledronate, which blocks osteoclast activity and thereby reduces the microenvironmental glutamine supply, generated a synergistic effect in reducing bone metastasis. These results identify a role for glutamine production by bone-resident cells in supporting metastatic cancer cells to overcome oxidative stress and develop resistance to DNA-damaging therapies.
Project description:Medulloblastoma (MB) is the most prevalent pediatric cerebral cancer, but is rare in adults. The vast majority of MB arises sporadically but some few cases occur in association with germline alterations in genes such as PTCH1, SUFU, APC, and TP53. Additional genes are responsible for MB predisposition including some that have probably not been described so far either due to the rarity of the cases and/or to the low penetrance. Here we report the case of a 27 years old woman affected by Pitt Hopkins syndrome due to a heterozygous germline pathogenic variant in TCF4 who has developed a Sonic Hedgehog (SHH)-driven MB. Somatic loss of function variants of TCF4 have been identified in SHH MB especially among adults and this case raises the question of a predisposition to late-onset SHH MB associated with TCF4 germline alteration.