Epigenetic regulation of Amphiregulin and Epiregulin in colorectal cancer.

Expression of the epidermal growth factor ligands amphiregulin (AREG) and epiregulin (EREG) is positively correlated with a response to EGFR-targeted therapies in colorectal cancer. Gene-body methylation sites, which show a strong inverse correlation with AREG and EREG gene expression, were identified in cell lines using targeted 454 FLX-bisulfite sequencing and SIRPH analyses for AREG/EREG promoters and intragenic CpGs. Upon treatment of colorectal cancer cells with 5-aza-2'-desoxycytidine, methylation decreases at specific intragenic CpGs accompanied by upregulation of AREG and EREG gene expression. The same AREG gene-body methylation was also found in human colorectal cancer samples and is independent of KRAS and NRAS mutations. Methylation is specifically decreased in the tumor epithelial compartment as compared to stromal tissue and normal epithelium. Investigation of a promoter/enhancer function of the AREG exon 2 region revealed a potential promoter function in reverse orientation. Retrospective comparison of the predictive power of AREG gene-body methylation versus AREG gene expression using samples from colorectal cancer patients treated with anti-EGFR inhibitors with complete clinical follow-up revealed that AREG expression is superior to AREG gene methylation. AREG and EREG genes undergo a complex regulation involving both intragenic methylation and promoter-dependent control.

Antitumor efficacy, pharmacokinetic and biodistribution studies of the anticancer peptide CIGB-552 in mouse models.

Accumulation of the COMMD1 protein as a druggable pharmacology event to target cancer cells has not been evaluated so far in cancer animal models. We have previously demonstrated that a second-generation peptide, with cell-penetrating capacity, termed CIGB-552, was able to induce apoptosis mediated by stabilization of COMMD1. Here, we explore the antitumor effect by subcutaneous administration of CIGB-552 in a therapeutic schedule. Outstandingly, a significant delay of tumor growth was observed at 0.2 and 0.7 mg/kg (p < 0.01) or 1.4 mg/kg (p < 0.001) after CIGB-552 administration in both syngeneic murine tumors and patient-derived xenograft models. Furthermore, we evidenced that (131)I-CIGB-552 peptide was actually accumulated in the tumors after administration by subcutaneous route. A typical serine-proteases degradation pattern for CIGB-552 in BALB/c mice serum was identified. Further, biological characterization of the main metabolites of the peptide CIGB-552 suggests that the cell-penetrating capacity plays an important role in the cytotoxic activity. This report is the first in describing the antitumor effect induced by systemic administration of a peptide that targets COMMD1 for stabilization. Moreover, our data reinforce the perspectives of CIGB-552 for cancer targeted therapy.

Bi-PROF: bisulfite profiling of target regions using 454 GS FLX Titanium technology.

The use of next generation sequencing has expanded our view on whole mammalian methylome patterns. In particular, it provides a genome-wide insight of local DNA methylation diversity at single nucleotide level and enables the examination of single chromosome sequence sections at a sufficient statistical power. We describe a bisulfite-based sequence profiling pipeline, Bi-PROF, which is based on the 454 GS-FLX Titanium technology that allows to obtain up to one million sequence stretches at single base pair resolution without laborious subcloning. To illustrate the performance of the experimental workflow connected to a bioinformatics program pipeline (BiQ Analyzer HT) we present a test analysis set of 68 different epigenetic marker regions (amplicons) in five individual patient-derived xenograft tissue samples of colorectal cancer and one healthy colon epithelium sample as a control. After the 454 GS-FLX Titanium run, sequence read processing and sample decoding, the obtained alignments are quality controlled and statistically evaluated. Comprehensive methylation pattern interpretation (profiling) assessed by analyzing 10 (2)-10 (4) sequence reads per amplicon allows an unprecedented deep view on pattern formation and methylation marker heterogeneity in tissues concerned by complex diseases like cancer.

Delivery of 5-azacytidine to human cancer cells by elaidic acid esterification increases therapeutic drug efficacy.

Azacytidine is an established nucleoside drug that is well known for its ability to modulate epigenetic gene regulation by inhibition of DNA methylation. Despite recent advances in the clinical development of azacytidine, the use of the drug is limited by its low bioavailability and dependency on variably expressed nucleoside transporters for cellular uptake. We show here that CP-4200, an elaidic acid derivative of azacytidine, has strong epigenetic modulatory potency in human cancer cell lines, as evidenced by efficient depletion of DNA methyltransferase protein, genome-wide DNA demethylation, and robust reactivation of epigenetically silenced tumor suppressor genes. Importantly, however, the cellular uptake of CP-4200 was substantially less dependent on the nucleoside transporters that are known to be involved in azacytidine uptake. In agreement with this notion, CP-4200 showed a significantly higher antitumoral activity than azacytidine in an orthotopic mouse tumor model for acute lymphocytic leukemia. Together, these data represent a detailed characterization of the CP-4200 mode of action and suggest that elaidic acid modification improves the therapeutic efficacy of azacytidine.