Dissection of a CTCF topological boundary uncovers principles of enhancer-oncogene regulation.

Enhancer-gene communication is dependent on topologically associating domains (TADs) and boundaries enforced by the CCCTC-binding factor (CTCF) insulator, but the underlying structures and mechanisms remain controversial. Here, we investigate a boundary that typically insulates fibroblast growth factor (FGF) oncogenes but is disrupted by DNA hypermethylation in gastrointestinal stromal tumors (GISTs). The boundary contains an array of CTCF sites that enforce adjacent TADs, one containing FGF genes and the other containing ANO1 and its putative enhancers, which are specifically active in GIST and its likely cell of origin. We show that coordinate disruption of four CTCF motifs in the boundary fuses the adjacent TADs, allows the ANO1 enhancer to contact FGF3, and causes its robust induction. High-resolution micro-C maps reveal specific contact between transcription initiation sites in the ANO1 enhancer and FGF3 promoter that quantitatively scales with FGF3 induction such that modest changes in contact frequency result in strong changes in expression, consistent with a causal relationship.

Vimentin protein is a factor for decreasing breast cancer cell proliferation co-culture with human bone marrow-derived mesenchymal stem cells pre-treated with thiazolidinedione solutions.

BACKGROUND: Our previous study investigated the levels of soluble growth factors in the conditioned media of bone marrow-derived mesenchymal stem cells (BMSCs) pre-treated with thiazolidinedione solutions. The present study aimed to investigate the complex intracellular proteins extracted from BMSCs pre-treated with pioglitazone and/or rosiglitazone using proteomics. METHODS: The proliferative effect of the identified protein on MCF-7 cells that interacted non-adhesively with BMSCs pre-treated with pioglitazone and/or rosiglitazone was evaluated using cell culture inserts and conditioned media. The mRNA expression of proliferation and lipid accumulation markers was also evaluated in the interacted MCF-7 cells by reverse transcription-quantitative PCR. Finally, the correlation between the identified protein and fibroblast growth factor 4 (FGF-4) protein in the conditioned media of the pre-treated BMSCs was evaluated by ELISA. RESULTS: The present study identified vimentin as the specific protein among the complex intracellular proteins that likely plays a role in MCF-7 cell proliferation when the breast cancer cells interacted non-adhesively with BMSCs pre-treated with a combination of pioglitazone and rosiglitazone. The inhibition of this protein promoted the proliferation of MCF-7 cells when the breast cancer cells interacted with pre-treated BMSCs. Gene expression analysis indicated that pre-treatment of BMSCs with a combination of pioglitazone and rosiglitazone decreased the mRNA expression of Ki67 and proliferating cell nuclear antigen in MCF-7 cells. The pre-treatment did not induce mRNA expression of PPARγ, which is a sign of lipid accumulation. The level of vimentin protein was also associated with the FGF-4 protein expression level in the conditioned media of the pre-treated BMSCs. Bioinformatics analysis revealed that vimentin regulated the expression of FGF-4 through its interaction with SRY-box 2 and POU class 5 homeobox 1. CONCLUSIONS: The present study identified a novel intracellular protein that may represent the promising target in pre-treated BMSCs to decrease the proliferation of breast cancer MCF-7 cells for human health and wellness.

Association of FGF4L1 Retrogene Insertion with Prolapsed Gland of the Nictitans (Cherry Eye) in Dogs.

Cherry eye is the common name for prolapse of the nictitans gland, a tear-producing gland situated under the third eyelid of dogs. Cherry eye is characterized by a red fleshy protuberance in the corner of the eye, resembling a cherry. This protrusion is a displacement of the normal gland of the third eyelid, thought to be caused by a defect in the connective tissue that secures the gland in place. Options for treatment may include anti-inflammatory medications in mild cases, but surgical replacement of the gland is usually indicated. Cherry eye is most often seen in dogs under the age of two years, with certain breeds having a higher incidence, suggesting a potential genetic association. Integration of panel genetic testing into routine clinical practice allows for the generation of large numbers of genotyped individuals paired with clinical records and enables the investigation of common disorders using a genome-wide association study (GWAS) approach at scale. In this investigation, several thousand cases and controls for cherry eye in both purebred dogs and mixed breeds are used for a large-scale GWAS, revealing a single peak of genome-wide significance on canine chromosome 18, directly at the location of the previously identified FGF4 insertion known to cause chondrodysplasia in several breeds.

Exposure of chimaeric embryos to exogenous FGF4 leads to the production of pure ESC-derived mice.

Producing chimaeras constitutes the most reliable method of verifying the pluripotency of newly established cells. Moreover, forming chimaeras by injecting genetically modified embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) into the embryo is part of the procedure for generating transgenic mice, which are used for understanding gene function. Conventional methods for generating transgenic mice, including the breeding of chimaeras and tetraploid complementation, are time-consuming and cost-inefficient, with significant limitations that hinder their effectiveness and widespread applications. In the present study, we modified the traditional method of chimaera generation to significantly speed up this process by generating mice exclusively derived from ESCs. This study aimed to assess whether fully ESC-derived mice could be obtained by modulating fibroblast growth factor 4 (FGF4) levels in the culture medium and changing the direction of cell differentiation in the chimaeric embryo. We found that exogenous FGF4 directs all host blastomeres to the primitive endoderm fate, but does not affect the localisation of ESCs in the epiblast of the chimaeric embryos. Consequently, all FGF4-treated chimaeric embryos contained an epiblast composed exclusively of ESCs, and following transfer into recipient mice, these embryos developed into fully ESC-derived newborns. Collectively, this simple approach could accelerate the generation of ESC-derived animals and thus optimise ESC-mediated transgenesis and the verification of cell pluripotency. Compared to traditional methods, it could speed up functional studies by several weeks and significantly reduce costs related to maintaining and breeding chimaeras. Moreover, since the effect of stimulating the FGF signalling pathway is universal across different animal species, our approach can be applied not only to rodents but also to other animals, offering its utility beyond laboratory settings.