Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with a high rate of metastasis. Recent studies have indicated that the Notch signalling pathway is important in PDAC initiation and ...maintenance, although the specific cell biological roles of the pathway remain to be established. Here we sought to examine this question in established pancreatic cancer cell lines using the gamma-secretase inhibitor IX (GSI IX) to inactivate Notch. Based on the known roles of Notch in development and stem cell biology, we focused on effects on epithelial mesenchymal transition (EMT) and on pancreatic tumor initiating CD44+/EpCAM+ cells. We analyzed the effect of the GSI IX on growth and epithelial plasticity of human pancreatic cancer cell lines, and on the tumorigenicity of pancreatic tumor initiating CD44+/EpCAM+ cells. Notably, apoptosis was induced after GSI IX treatment and EMT markers were selectively targeted. Furthermore, under GSI IX treatment, decline in the growth of pancreatic tumor initiating CD44+/EpCAM+ cells was observed in vitro and in a xenograft mouse model. This study demonstrates a central role of Notch signalling pathway in pancreatic cancer pathogenesis and identifies an effective approach to inhibit selectively EMT and suppress tumorigenesis by eliminating pancreatic tumor initiating CD44+/EpCAM+ cells.
The cell surface glycoprotein KAI1/CD82 suppresses tumor growth and metastasis in animal models. This study aimed to evaluate the prognostic relevance of KAI1/CD82 protein expression in human gastric ...cancer. Primary gastric carcinomas (
n
= 271) with amean clinical follow-up time of 48months were immunostained using the monoclonal anti-KAI1/CD82 antibody G2. Staining was evaluated as negative
versus
positive for statistical analysis. KAI1/CD82 immunoreactivity was absent in 103/271 (38%) cases. There was a trend towards KAI1/CD82 negativity in poorly differentiated cases (
p
= 0.0679). Moreover, KAI1/CD82-negative carcinomas were associated with a higher pT status (
p
= 0.0222), metastatic lymph node involvement (
p
= 0.0018) and a higher clinical tumor stage (
p
= 0.0050). The median overall survival times of KAI1/CD82-negative and KAI1/CD82-positive gastric carcinomas were 20 and 37 months, respectively (
p
= 0.2305). These results are in line with the proposed function of KAI1/CD82 as a suppressor of tumor growth and metastasis. However, these data suggest that KAI1/CD82, as detected by immunohistochemistry, is of limited value as a prognostic marker for gastric cancer in routine histological workup.
IDH1 mutations are oncogenic through induction of DNA damage and genome instability. They are of therapeutic interest because they confer increased sensitivity to radiation and cytotoxic therapy and ...hold potential for vaccination therapy.
In this study, we analyzed more than 17,000 primary prostate cancer tissues with a mutation-specific antibody for the IDH1
mutation.
IDH1 mutation-specific staining was found in 42 of 15,531 (0.3%) interpretable cancers. IDH1 mutation was associated with higher preoperative PSA and Gleason grade (p < 0.05, each) but was unrelated to PSA recurrence. A comparison with other molecular tumor features available from earlier studies revealed that TMPRSS2-ERG fusion as well as deletion of PTEN, 5q21, 6q15, and 3p13 was less frequent in IDH1-mutated than in non-mutated cancer. Increased lethality of genetically instable, "aberration-rich" cancer cells in the presence of IDH1 mutations could possibly explain this observation. Heterogeneity analysis revealed a homogeneous mutation in only 1 of 16 IDH1-mutated cancers. This high degree of heterogeneity may profoundly limit therapeutic targeting of IDH1 mutations in prostate cancer.
The data show that 0.3% of prostate cancers have an IDH1
mutation and that these are mostly heterogeneous. Once specific anti-IDH1 therapy becomes reality, only a very small group of prostate cancer patients may benefit from such a treatment.
Transcriptional signatures are an indispensible source of correlative information on disease-related molecular alterations on a genome-wide level. Numerous candidate genes involved in disease and in ...factors of predictive, as well as of prognostic, value have been deduced from such molecular portraits, e.g. in cancer. However, mechanistic insights into the regulatory principles governing global transcriptional changes are lagging behind extensive compilations of deregulated genes. To identify regulators of transcriptome alterations, we used an integrated approach combining transcriptional profiling of colorectal cancer cell lines treated with inhibitors targeting the receptor tyrosine kinase (RTK)/RAS/mitogen-activated protein kinase pathway, computational prediction of regulatory elements in promoters of co-regulated genes, chromatin-based and functional cellular assays. We identified commonly co-regulated, proliferation-associated target genes that respond to the MAPK pathway. We recognized E2F and NFY transcription factor binding sites as prevalent motifs in those pathway-responsive genes and confirmed the predicted regulatory role of Y-box binding protein 1 (YBX1) by reporter gene, gel shift, and chromatin immunoprecipitation assays. We also validated the MAPK-dependent gene signature in colorectal cancers and provided evidence for the association of YBX1 with poor prognosis in colorectal cancer patients. This suggests that MEK/ERK-dependent, YBX1-regulated target genes are involved in executing malignant properties.
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