Chemical perturbations impacting histone acetylation govern colorectal cancer differentiation.

Dysregulated epigenetic programs that restrict differentiation, reactivate fetal genes, and confer phenotypic plasticity are critical to colorectal cancer (CRC) development. By screening a small molecule library targeting epigenetic regulators using our dual reporter system, we found that inhibiting histone deacetylase (HDAC) 1/2 promotes CRC differentiation and anti-tumor activity. Comprehensive biochemical, chemical, and genetic experiments revealed that on-target blockade of the HDAC1/2 catalytic domain mediated the differentiated phenotype.

Identifying regulators of aberrant stem cell and differentiation activity in colorectal cancer using a dual endogenous reporter system.

Aberrant stem cell-like activity and impaired differentiation are central to the development of colorectal cancer (CRC). To identify functional mediators of these key cellular programs, we engineer a dual endogenous reporter system by genome-editing the SOX9 and KRT20 loci of human CRC cell lines to express fluorescent reporters, broadcasting aberrant stem cell-like and differentiation activity, respectively. By applying a CRISPR screen targeting 78 epigenetic regulators with 542 sgRNAs to this platform, we identify factors that contribute to stem cell-like activity and differentiation in CRC.

Utilizing a dual endogenous reporter system to identify functional regulators of aberrant stem cell and differentiation activity in colorectal cancer.

Aberrant stem cell-like activity and impaired differentiation are central to the development of colorectal cancer (CRC). To identify functional mediators that regulate these key cellular programs in CRC, we developed an endogenous reporter system by genome-editing human CRC cell lines with knock-in fluorescent reporters at the SOX9 and KRT20 locus to report aberrant stem cell-like activity and differentiation, respectively, and then performed pooled genetic perturbation screens. Constructing a dual reporter system that simultaneously monitored aberrant stem cell-like and differentiation activity in the same CRC cell line improved our signal to noise discrimination.

Replicative stress in gastroesophageal cancer is associated with chromosomal instability and sensitivity to DNA damage response inhibitors.

Gastroesophageal adenocarcinoma (GEA) is an aggressive malignancy with chromosomal instability (CIN). To understand adaptive responses enabling DNA damage response (DDR) and CIN, we analyzed matched normal, premalignant, and malignant gastric lesions from human specimens and a carcinogen-induced mouse model, observing activation of replication stress, DDR, and p21 in neoplastic progression. In GEA cell lines, expression of DDR markers correlated with ploidy abnormalities, such as number of high-level focal amplifications and whole-genome duplication (WGD).

Aberrant cell state plasticity mediated by developmental reprogramming precedes colorectal cancer initiation.

Cell state plasticity is carefully regulated in adult epithelia to prevent cancer. The aberrant expansion of the normally restricted capability for cell state plasticity in neoplasia is poorly defined. Using genetically engineered and carcinogen-induced mouse models of intestinal neoplasia, we observed that impaired differentiation is a conserved event preceding cancer development.

To β or Not to β: Lack of Correlation Between APC Mutation and β-Catenin Nuclear Localization in Colorectal Cancer.

Purpose: Colorectal cancer (CRC) appears to arise from sequential genetic lesions in tumor suppressor genes (APC, SMAD4, and TP53) and oncogenes (KRAS) leading to the classical adenoma to carcinoma progression. Biallelic APC inactivating genetic aberrations are detected in about 70% of early microadenomas implicating APC inactivation as the first genetic hit in CRC. APC is an essential protein of the Wnt 'destruction complex'; APC inactivation is believed to cause disruption of the complex allowing stabilization and nuclear translocation of β-catenin, resulting in transcriptional activation of cancer-promoting genes.

A novel β-catenin/BCL9 complex inhibitor blocks oncogenic Wnt signaling and disrupts cholesterol homeostasis in colorectal cancer.

Dysregulated Wnt/β-catenin signaling is implicated in the pathogenesis of many human cancers, including colorectal cancer (CRC), making it an attractive clinical target. With the aim of inhibiting oncogenic Wnt activity, we developed a high-throughput screening AlphaScreen assay to identify selective small-molecule inhibitors of the interaction between β-catenin and its coactivator BCL9. We identified a compound that consistently bound to β-catenin and specifically inhibited in vivo native β-catenin/BCL9 complex formation in CRC cell lines.

is associated with inflammation and poor survival in early-stage HPV-negative tongue cancer.

Persistent pathogen infection is a known cause of malignancy, although with sparse systematic evaluation across tumor types. We present a comprehensive landscape of 1060 infectious pathogens across 239 whole exomes and 1168 transcriptomes of breast, lung, gallbladder, cervical, colorectal, and head and neck tumors. We identify known cancer-associated pathogens consistent with the literature.

An Enhancer-Driven Stem Cell-Like Program Mediated by SOX9 Blocks Intestinal Differentiation in Colorectal Cancer.

Background And Aims: Genomic alterations that encourage stem cell activity and hinder proper maturation are central to the development of colorectal cancer (CRC). Key molecular mediators that promote these malignant properties require further elucidation to galvanize translational advances. We therefore aimed to characterize a key factor that blocks intestinal differentiation, define its transcriptional and epigenetic program, and provide preclinical evidence for therapeutic targeting in CRC.

A comprehensive profile of genomic variations in the SARS-CoV-2 isolates from the state of Telangana, India.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 has rapidly turned into a pandemic, infecting millions and causing 1 157 509 (as of 27 October 2020) deaths across the globe. In addition to studying the mode of transmission and evasion of host immune system, analysing the viral mutational landscape constitutes an area under active research. The latter is expected to impart knowledge on the emergence of different clades, subclades, viral protein functions and protein-protein and protein-RNA interactions during replication/transcription cycle of virus and response to host immune checkpoints.

Exome sequencing identifies ARID2 as a novel tumor suppressor in early-onset sporadic rectal cancer.

Early-onset sporadic rectal cancer (EOSRC) is a unique and predominant colorectal cancer (CRC) subtype in India. In order to understand the tumorigenic process in EOSRC, we performed whole-exome sequencing of 47 microsatellite stable EOSRC samples. Signature 1 was the predominant mutational signature in EOSRC, as previously shown in other CRC exome studies.

The Yin and Yang of cancer genes.

Cancer is caused by malfunctioning of genes that normally regulate cardinal processes including various nuclear functions, cell division and survival, cell surface to nucleus signaling cascades, etc. Cancer associated genes are often classified as oncogenes (OCGs) or tumor suppressor genes (TSGs) depending on whether they promote or suppress tumorigenesis, respectively. Such strict classification of cancer genes may however be an over-simplification.