Project description:Pyrrole-imidazole polyamides are versatile DNA minor groove binders and attractive therapeutic options against oncological targets, especially upon functionalization with an alkylating agent such as endo-seco-CBI. These molecules also provide an alternative for oncogenes deemed “undruggable” at the protein level, where the absence of solvent-accessible pockets or structural crevices prevent the formation of protein-inhibitor ligands; nevertheless, the genome-wide effect of pyrrole-imidazole polyamide binding remain largely unclear to-date. Here we propose a next-generation sequencing-based workflow combined with whole genome expression arrays to address such issue using a candidate anti-cancer alkylating agent, KR12, against codon 12 mutant KRAS. Biotinylating KR12 enables the means to identify its genome-wide effects in living cells and possible biological implications via a coupled workflow of enrichment-based sequencing and expression microarrays. The subsequent computational pathway and expression analyses allow the identification of its genomic binding sites, as well as a route to explore a polyamide’s possible genome-wide effects. Among the 3,343 KR12 binding sites identified in the human LS180 colorectal cancer genome, the reduction of KR12-bound gene expressions was also observed. Additionally, the coupled microarray-sequencing analysis also revealed some insights about the effect of local chromatin structure on pyrrole-imidazole polyamide, which had not been fully understood to-date. A comparative analysis with KR12 in a different human colorectal cancer genome SW480 also showed agreeable agreements of KR12 binding affecting gene expressions. Combination of these analyses thus suggested the possibility of applying this approach to other pyrrole-imidazole polyamides to reveal further biological details about the effect of polyamide binding in a genome.
Project description:Pyrrole-imidazole polyamides are versatile DNA minor groove binders and attractive therapeutic options against oncological targets, especially upon functionalization with an alkylating agent such as endo-seco-CBI. These molecules also provide an alternative for oncogenes deemed “undruggable” at the protein level, where the absence of solvent-accessible pockets or structural crevices prevent the formation of protein-inhibitor ligands; nevertheless, the genome-wide effect of pyrrole-imidazole polyamide binding remain largely unclear to-date. Here we propose a next-generation sequencing-based workflow combined with whole genome expression arrays to address such issue using a candidate anti-cancer alkylating agent, KR12, against codon 12 mutant KRAS. Biotinylating KR12 enables the means to identify its genome-wide effects in living cells and possible biological implications via a coupled workflow of enrichment-based sequencing and expression microarrays. The subsequent computational pathway and expression analyses allow the identification of its genomic binding sites, as well as a route to explore a polyamide’s possible genome-wide effects. Among the 3,343 KR12 binding sites identified in the human LS180 colorectal cancer genome, the reduction of KR12-bound gene expressions was also observed. Additionally, the coupled microarray-sequencing analysis also revealed some insights about the effect of local chromatin structure on pyrrole-imidazole polyamide, which had not been fully understood to-date. A comparative analysis with KR12 in a different human colorectal cancer genome SW480 also showed agreeable agreements of KR12 binding affecting gene expressions. Combination of these analyses thus suggested the possibility of applying this approach to other pyrrole-imidazole polyamides to reveal further biological details about the effect of polyamide binding in a genome.
Project description:We report that a DNA minor groove binding hairpin pyrrole-imidazole (Py-Im) polyamide interferes with RNA polymerase II (RNAP2) activity in cell culture. Genome-wide mapping of RNAP2 binding shows reduction of occupancy preferentially at transcription start sites (TSS), while occupancy at enhancer sites are is unchanged. Genome-wide mapping of RNA polymerase II in LNCaP cells treated with DHT and DHT with Py-Im polyamide.
Project description:We report that a DNA minor groove binding hairpin pyrrole-imidazole (Py-Im) polyamide interferes with RNA polymerase II (RNAP2) activity in cell culture. Genome-wide mapping of RNAP2 binding shows reduction of occupancy preferentially at transcription start sites (TSS), while occupancy at enhancer sites are is unchanged.
Project description:Activating mutations of the KRAS gene are found in >90% of pancreatic ductal adenocarcinoma (PDAC) cases. However, direct pharmacological targeting of the activated KRAS protein has been challenging. We previously reported that KR12, a DNA-alkylating pyrrole-imidazole polyamide designed to recognize the KRAS G12D/V mutation, showed an anti-tumor effect in colorectal cancer. In this study, we evaluated the anti-tumor effect of KR12 in PDAC. We found that KR12 inhibited tumor growth in a spontaneous PDAC mouse model, although the anti-tumor activity appeared to be limited in a human PDAC xenograft model. We developed a pyrrole-imidazole polyamide screening process based on the hypothesis that genetic elements otherwise unaffected by KR12 could exert attenuating effects on KRAS-suppression-resistant PDAC. We identified RAD51 as a potential therapeutic target in human PDAC cells. A RAD51 inhibitor showed an inhibitory effect on cell growth and affected the cytotoxic activity of KR12 in PDAC cells. These data suggested that the simultaneous inhibition of RAD51 and mutant KRAS blockage would be an important therapeutic strategy for PDAC.
Project description:Pyrrole-imidazole polyamides (PIPs) have been shown to inhibit gene expression by interrupting the DNA-protein interface. Human Ectopic viral integration site 1 (EVI1) is an oncogenic transcription factor which plays a key role in many aggressive forms of cancer. We have developed a novel pyrrole–imidazole polyamide, PIP1 targeting the REL/ELK1 binding site in the EVI1 minimal promoter that can significantly repress the expression of EVI1 in MDA-MB-231 cells. Whole-transcriptome analysis revealed that a fraction of EVI1-driven genes were modulated by PIP1.
Project description:Amplification of MYCN plays a pivotal role in multiple types of tumors and correlates with poor prognosis in high-risk neuroblastoma. Despite recent advances in the treatment of neuroblastoma, no approaches directly target the master oncogene MYCN. Difficulties in targeting the MYCN protein have inspired us to develop a new gene level inhibitory strategy using a sequence-specific gene regulator. Here we generated a MYCN-targeting pyrrole-imidazole (PI) polyamide, MYCN-A3, which directly binds to and alkylates DNA at homing motifs within MYCN transcript. Pharmacological suppression of MYCN inhibited the proliferation of cancer cells harboring MYCN amplification compared with MYCN non-amplified cancer cells. In neuroblastoma xenograft mouse models, MYCN-A3 specifically downregulated MYCN expression and suppressed tumor progression with no detectable adverse effects and resulted in prolonged overall survival. Moreover, we observed the copy number reduction of MYCN in neuroblastoma cells with MYCN amplification upon treatment with MYCN-A3 but not MYCN non-targeting PI polyamide. Expression microarray experiments were also performed to compare the genome-wide effect of MYCN-A3 with CRISPR/Cas9 silencing of MYCN (MYCNcr-a).
Project description:Pyrrole-imidazole polyamides (PIPs) have been shown to inhibit gene expression by interrupting the DNA-protein interface. Human Ectopic viral integration site 1 (EVI1) is an oncogenic transcription factor which plays a key role in many aggressive forms of cancer. We have developed a novel pyrroleM-bM-^@M-^Simidazole polyamide, PIP1 targeting the REL/ELK1 binding site in the EVI1 minimal promoter that can significantly repress the expression of EVI1 in MDA-MB-231 cells. Whole-transcriptome analysis revealed that a fraction of EVI1-driven genes were modulated by PIP1. Global expression changes in MDA-MB-231 cells were evaluated after treating the cells with PIP1 and DMSO for 48 hours. The vehicle DMSO is used as a negative control. Each condition is performed in technical replicates.