Dataset Information

Unlike pancreatic cancer cells pancreatic cancer associated fibroblasts display minimal gene induction after 5-aza-2'-deoxycytidine.

ABSTRACT:

Purpose

Cancer associated stromal fibroblasts (CAFs) undergo transcriptional and phenotypic changes that contribute to tumor progression, but the mechanisms responsible for these changes are not well understood. Aberrant DNA methylation is an important cause of transcriptional alterations in cancer cells but it is not known how important DNA methylation alterations are to CAF behavior.

Experimental design

We used Affymetrix exon arrays to compare genes induced by the DNA methylation inhibitor 5-aza-dC in cultured pancreatic cancer associated fibroblasts, pancreatic control fibroblasts and pancreatic cancer cell lines.

Results

We found that pancreatic CAFs and control pancreatic fibroblasts were less responsive to 5-aza-dC-mediated gene reactivation than pancreatic cancer cells (mean+/-SD of genes induced ? 5-fold was 9 ± 10 genes in 10 pancreatic CAF cultures, 17 ± 14 genes in 3 control pancreatic fibroblast cultures, and 134 ± 85 genes in 4 pancreatic cancer cell lines). We examined differentially expressed genes between CAFs and control fibroblasts for candidate methylated genes and identified the disintegrin and metalloprotease, ADAM12 as hypomethylated and overexpressed in pancreatic CAF lines and overexpressed in fibroblasts adjacent to primary pancreatic adenocarcinomas.

Conclusions

Compared to pancreatic cancer cells, few genes are reactivated by DNMT1 inhibition in pancreatic CAFs suggesting these cells do not harbor many functionally important alterations in DNA methylation. CAFs may also not be very responsive to therapeutic targeting with DNA methylation inhibitors.

SUBMITTER: Yu J

PROVIDER: S-EPMC3439436 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Unlike pancreatic cancer cells pancreatic cancer associated fibroblasts display minimal gene induction after 5-aza-2'-deoxycytidine.

Yu Jun J Walter Kimberly K Omura Noriyuki N Hong Seung-Mo SM Young Angela A Li Ang A Vincent Audrey A Goggins Michael M

PloS one 20120911 9

<h4>Purpose</h4>Cancer associated stromal fibroblasts (CAFs) undergo transcriptional and phenotypic changes that contribute to tumor progression, but the mechanisms responsible for these changes are not well understood. Aberrant DNA methylation is an important cause of transcriptional alterations in cancer cells but it is not known how important DNA methylation alterations are to CAF behavior.<h4>Experimental design</h4>We used Affymetrix exon arrays to compare genes induced by the DNA methylati ...[more]

PMID: 22984426

Similar Datasets

Project description:BackgroundThe inactivation of tumor suppressor genes (TSGs) by aberrant DNA methylation plays an important role in the development of malignancy. Since this epigenetic change is reversible, it is a potential target for chemotherapeutic intervention using an inhibitor of DNA methylation, such as 5-aza-2'-deoxycytidine (DAC). Although clinical studies show that DAC has activity against hematological malignancies, the optimal dose-schedule of this epigenetic agent still needs to be established.MethodsClonogenic assays were performed on leukemic and tumor cell lines to evaluate the in vitro antineoplastic activity of DAC. The reactivation of TSGs and inhibition of DNA methylation by DAC were investigated by reverse transcriptase-PCR and Line-1 assays. The in vivo antineoplastic activity of DAC administered as an i.v. infusion was evaluated in mice with murine L1210 leukemia by measurement of survival time, and in mice bearing murine EMT6 mammary tumor by excision of tumor after chemotherapy for an in vitro clonogenic assay.ResultsIncreasing the DAC concentration and duration of exposure produced a greater loss of clonogenicity for both human leukemic and tumor cell lines. The reactivation of the TSGs (p57KIP2 in HL-60 leukemic cells and p16CDKN2A in Calu-6 lung carcinoma cells) and the inhibition of global DNA methylation in HL-60 leukemic cells increased with DAC concentration. In mice with L1210 leukemia and in mice bearing EMT6 tumors, the antineoplastic action of DAC also increased with the dose. The plasma level of DAC that produced a very potent antineoplastic effect in mice with leukemia or solid tumors was > 200 ng/ml (> 1 microM).ConclusionWe have shown that intensification of the DAC dose markedly increased its antineoplastic activity in mouse models of cancer. Our data also show that there is a good correlation between the concentrations of DAC that reduce in vitro clonogenicity, reactivate TSGs and inhibit DNA methylation. These results suggest that the antineoplastic action of DAC is related to its epigenetic action. Our observations provide a strong rationale to perform clinical trials using dose intensification of DAC to maximize the chemotherapeutic potential of this epigenetic agent in patients with cancer.

Dataset Information

Unlike pancreatic cancer cells pancreatic cancer associated fibroblasts display minimal gene induction after 5-aza-2'-deoxycytidine.

Purpose

Experimental design

Results

Conclusions

Publications

Unlike pancreatic cancer cells pancreatic cancer associated fibroblasts display minimal gene induction after 5-aza-2'-deoxycytidine.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets