The atypical cadherin MUCDHL antagonizes colon cancer formation and inhibits oncogenic signaling through multiple mechanisms

Quest for a stable Cu-ligand complex with a high catalytic activity to produce reactive oxygen species

Metal ion-catalyzed overproduction of reactive oxygen species (ROS) is believed to contribute significantly to oxidative stress and be involved in several biological processes, from immune defense to development of diseases. Among the essential metal ions, copper is one of the most efficient catalysts in ROS production in the presence of O2 and a physiological reducing agent such as ascorbate. To control this chemistry, Cu ions are tightly coordinated to biomolecules. Free or loosely bound Cu ions are generally avoided to prevent their toxicity. In the present report, we aim to find stable Cu-ligand complexes (Cu-L) that can efficiently catalyze the production of ROS in the presence of ascorbate under aerobic conditions. Thermodynamic stability would be needed to avoid dissociation in the biological environment, and high ROS catalysis is of interest for applications as antimicrobial or anticancer agents. A series of Cu complexes with the well-known tripodal and tetradentate ligands containing a central amine linked to three pyridyl-alkyl arms of different lengths were investigated. Two of them with mixed arm length showed a higher catalytic activity in the oxidation of ascorbate and subsequent ROS production than Cu salts in buffer, which is an unprecedented result. Despite these high catalytic activities, no increased antimicrobial activity toward Escherichia coli or cytotoxicity against eukaryotic AGS cells in culture related to Cu-L-based ROS production could be observed. The potential reasons for discrepancy between in vitro and in cell data are discussed.

A review on mechanobiology of cell adhesion networks in different stages of sporadic colorectal cancer to explain its tumorigenesis

Sporadic colorectal cancer (CRC) is strongly linked to extraneous factors, like poor diet and lifestyle, but not to inherent factors like familial genetics. The changes at the epigenomics and signalling pathways are known across the sporadic CRC stages. The catch is that temporal information of the onset, the feedback loop, and the crosstalk of signalling and noise are still unclear. This makes it challenging to diagnose and treat colon cancer effectively with no relapse. Various microbial cells and native cells of the colon, contribute to sporadic CRC development. These cells secrete autocrine and paracrine for their bioenergetics and communications with other cell types. Imbalances of the biochemicals affect the epithelial lining of colon. One side of this epithelial lining is interfacing the dense colon tissue, while the other side is exposed to microbiota and excrement from the lumen. Hence, the epithelial lining is prone to tumorigenesis due to the influence of both biochemical and mechanical cues from its complex surrounding. The role of physical transformations in tumorigenesis have been limitedly discussed. In this context, cellular and tissue structures, and force transductions are heavily regulated by cell adhesion networks. These networks include cell anchoring mechanism to the surrounding, cell structural integrity mechanism, and cell effector molecules. This review will focus on the progression of the sporadic CRC stages that are governed by the underlaying cell adhesion networks within the epithelial cells. Additionally, current and potential technologies and therapeutics that target cell adhesion networks for treatments of sporadic CRC will be incorporated.

Genomic Profiling of Chinese Cervical Cancer Patients Reveals Prevalence of DNA Damage Repair Gene Alterations and Related Hypoxia Feature

Background

Cervical cancer is responsible for 10–15% of cancer-related deaths in women worldwide. In China, it is the most common cancer in the female genital tract. However, the genomic profiles of Chinese cervical cancer patients remain unclear.

Materials and Methods

A total of 129 cervical cancer patients were enrolled in this study (113 squamous, 12 adenocarcinoma, 2 adenosquamous, and 2 neuroendocrine carcinoma). To classify the clinical features and molecular characteristics of cervical cancer, the genomic alterations of 618 selected genes were analyzed in the samples of these patients, utilizing target next-generation sequencing (NGS) technology. Furthermore, the findings from the Chinese cohort were then compared with the data of Western patients downloaded from The Cancer Genome Atlas (TCGA) database, in terms of gene expression files, mutation data, and clinical information.

Results

All studied patients had valid somatic gene alterations, and the most frequently altered genes were PIK3C, TP53, FBXW7, ARID1A, ERBB2, and PTEN. Comparison of genomic profiling showed significantly different prevalence of genes, including TP53, KMT2C, and RET, between the Chinese and the TCGA cohorts. Moreover, 57 patients (44.19%) with 83 actionable alterations were identified in our cohort, especially in PI3K and DNA damage repair (DDR) pathways. After an in-depth analysis of cervical cancer data from the TCGA cohort, DDR alteration was found to be associated with extremely higher tumor mutation burden (TMB) (median mutation count: 149.5 vs 66, p <0.0001), and advanced stages (p <0.05). Additionally, DDR alteration, regardless of its function, was positively correlated with hypoxia feature and score. Moreover, patients with a high hypoxia score were positively correlated with a high abundance of mast cell resting, but lower abundance of CD8+ T cells and activated mast cell. Finally, CDHR5 was identified as the hub gene to be involved in the DDR–hypoxia network, which was negatively correlated with both the DDR alteration and hypoxia score.

Conclusions

Overall, a unique genomic profiling of Chinese patients with cervical cancer was uncovered. Besides, the prevalent actionable variants, especially in PI3K and DDR pathways, would help promote the clinical management. Moreover, DDR alteration exerted the significant influence on the tumor microenvironment in cervical cancer, which could guide the clinical decisions for the treatment. CDHR5 was the first identified hub gene to be negatively correlated with DDR or hypoxia in cervical cancer, which had potential effects on the treatment of immune checkpoint inhibitors (ICIs).

Mesalazine initiates an anti-oncogenic β-catenin / MUCDHL negative feed-back loop in colon cancer cells by cell-specific mechanisms

Chronic inflammation associated with intestinal architecture and barrier disruption puts patients with inflammatory bowel disease (IBD) at increased risk of developing colorectal cancer (CRC). Widely used to reduce flares of intestinal inflammation, 5-aminosalicylic acid derivatives (5-ASAs) such as mesalazine appear to also exert more direct mucosal healing and chemopreventive activities against CRC. The mechanisms underlying these activities are poorly understood and may involve the up-regulation of the cadherin-related gene MUCDHL (CDHR5). This atypical cadherin is emerging as a new actor of intestinal homeostasis and opposes colon tumorigenesis. Here, we showed that mesalazine increase mRNA levels of MUCDHL and of other genes involved in the intestinal barrier function in most intestinal cell lines. In addition, using gain / loss of function experiments (agonists, plasmid or siRNAs transfections), luciferase reporter genes and chromatin immunoprecipitation, we thoroughly investigated the molecular mechanisms triggered by mesalazine that lead to the up-regulation of MUCDHL expression. We found that basal transcription of MUCDHL in different CRC cell lines is regulated positively by CDX2 and negatively by β-catenin through a negative feed-back loop. However, mesalazine-stimulation of MUCDHL transcription is controlled by cell-specific mechanisms, involving either enhanced activation of CDX2 and PPAR-γ or repression of the β-catenin inhibitory effect. This work highlights the importance of the cellular and molecular context in the activity of mesalazine and suggests that its efficacy against CRC depends on the genetic alterations of transformed cells.

The quest for ligands and binding partners of atypical cadherin FAT1

A recent study in Scientific Reports identified glypican-3 (GPC3) as a novel extracellular interacting protein for FAT1 in hepato-cellular carcinoma (HCC) cells. FAT1 is a large transmembrane atypical cadherin with limited knowledge existing about its binding partners. While in Drosophila, dachsous (ds), another transmembrane member of the cadherin superfamily, is known to function as FAT1 ligand, no ligand is known in mammals so far. The revelation of GPC3 as a potential binding partner of FAT1 extracellular domain unfolds an opportunity to study potential triggers of FAT1 signaling in cancers. Available inhibitors of GPC3 in various phases of clinical trials also present an attractive option to curb GPC3-FAT1 signaling in tumors that overexpress these proteins.