Drablos, F. | Search bioRxiv

bioRxiv2018

MACPET: Model-based Analysis for ChIA-PET

We present Model-based Analysis for ChIA-PET (MACPET) which analyzes paired-end read sequences provided by ChIA-PET for finding binding sites of a protein of interest. MACPET uses information from both tags of each PET and searches for binding sites in a two-dimensional space, while taking into account different noise levels in different genomic regions. MACPET shows favorable results compared to MACS in terms of motif occurrence, spatial resolution and false discovery rate. Significant binding sites discovered by MACPET are involved in a higher number of significant 3D interactions than those discovered by MACS. MACPET is freely available on Bioconductor.

bioinformatics↗

bioRxiv2017

Cholesterol Synthesis Pathway Genes in Prostate Cancer are consistently downregulated when tissue confounding is minimized.

The relationship between cholesterol and prostate cancer has been extensively studied for decades, where high levels of cellular cholesterol are generally associated with cancer progression and less favorable outcomes. However, the role of in vivo cellular cholesterol synthesis in this process is unclear, and data on the transcriptional activity of cholesterol synthesis pathway genes in tissue from prostate cancer patients are inconsistent. A common problem with cancer tissue data from patient cohorts is the presence of heterogeneous tissue which confounds molecular analysis of the samples. In this study we present a method to minimize systematic confounding from stroma tissue in seven patient cohorts consisting of 1713 prostate cancer and 230 normal tissue samples. When confounding was minimized, differential gene expression analysis over all cohorts showed robust and consistent downregulation of nearly all genes in the cholesterol synthesis pathway. Additional analysis also identified cholesterol synthesis as the most significantly altered metabolic pathway in prostate cancer. This surprising observation is important for our understanding of how prostate cancer cells regulate cholesterol levels in vivo. Moreover, we show that tissue heterogeneity explains the lack of consistency in previous expression analysis of cholesterol synthesis genes in prostate cancer.

cancer biology↗