polyposis

Osteosarcoma (OS) is the most common type of bone tumor in children and adults. The expression of APCDD1, a Wnt antagonist, was reduced in OS tissues and cells compared to adjacent normal tissue and osteoblast cells, respectively. Mechanistically, this was due to increased levels of methylation in the promoter region of the APCDD1 gene. Consistently, the DNA methyltransferase inhibitor 5-AZA-dC, reduced DNA methylation in the APCDD1 promoter, and restored APCDD1 expression in OS tissue and cells. Moreover, DNMT3a, but not DNMT1 or DNMT3b, was the major DNA methyltransferase that facilitated hyper-methylation of DNA in the APCDD1 promoter, thus reducing APCDD1 mRNA levels in OS tissues. Importantly, ectopic expression of APCDD1 suppressed activity of the Wnt/beta-Catenin signaling pathway in OS cells and inhibited their invasion and reversed their EMT-like properties, while depletion of APCDD1 promoted invasion and metastasis of osteosarcoma cells in vitro and in vivo. That APCDD1 modulates the gene expression of Wnt- and EK-related signaling molecules at the cap stage of tooth development, and is involved in tooth cusp patterning by modulating the epithelial rearrangement in the IEE. In hair follicle cells APCDD1 inhibits the canonical WNT/beta-Catenin pathway and its inactivation is associated with an autosomal dominant form of hair loss. APCDD1 sustains the expression and activation of beta-Catenin.

May be a survival factor for hippocampal and mesencephalic neurons. The shedded form up-regulates cancer cell proliferation, probably by promoting ERK1/2 phosphorylation.

C5orf15 (Chromosome 5 Open Reading Frame 15, also known as KCT2) is a Protein Coding gene. KCT2 gene maps to human chromosome 5q31.1 and is conserved in human, chimpanzee, cow, rat, and chicken. KCT2 is a 265 amino acid single-pass type I membrane protein that is widely expressed in the thyroid, kidney, and other tissues. Chromosome 5 is associated with Cockayne syndrome through the ERCC8 gene and familial adenomatous polyposis through the adenomatous polyposis coli (APC) tumor suppressor gene. Chromosome 5 contains 181 million base pairs and comprises nearly 6% of the human genome. Diseases associated with C5orf15 include Arrhythmogenic Right Ventricular Dysplasia, Familial, 5, and Amyotrophic Lateral Sclerosis 11.

SMAD Family Member 4 (SMAD4) is a cytoplasmic protein that belongs to the Dwarfin/SMAD family. SMAD4 contains one MH1 (MAD homology 1) domain and one MH2 (MAD homology 2) domain. It is the component of the heterotrimeric SMAD2/SMAD3-SMAD4 complex that forms in the nucleus and is required for the TGF-mediated signaling. SMAD4 promotes binding of the SMAD2/SMAD4/FAST-1 complex to DNA and provides an activation function required for SMAD1 or SMAD2 to stimulate transcription. SMAD4 may act as a tumor suppressor. It positively regulates PDPK1 kinase activity by stimulating its dissociation from the 14-3-3 protein YWHAQ which acts as a negative regulator. Mutations or deletions in SMAD4 have been shown to result in pancreatic cancer, juvenile polyposis syndrome, and hereditary hemorrhagic telangiectasia syndrome.

MSH2 is a key DNA mismatch repair protein, which plays an important role in genomic stability. In addition to its DNA repair function, MSH2 serves as a sensor for DNA base analogs-provoked DNA replication errors and binds to various DNA damage-induced adducts to trigger cell cycle arrest or apoptosis. Loss or depletion of MSH2 from cells renders resistance to certain DNA-damaging agents. Therefore, the level of MSH2 determines the DNA damage response.MSH2 is a central component of the mismatch repair pathway that targets mismatches arising during DNA replication, homologous recombination (HR), and in response to genotoxic stresses.MSH2 rearrangements are involved in approximately 10% of hereditary non-polyposis colorectal cancer (HNPCC) families, and in most of the rearrangements, exon 1 is deleted. Loss of human MSH2 (hMSH2) protein might be involved in the multistep pathogenesis of hematological malignancies associated with genetic instability.

Bone Morphogenetic Protein Receptor Type-1A (BMPR1A) belongs to the TKL Ser/Thr protein kinase family and TGFB receptor subfamily, including the type I receptors BMPR1A and BMPR1B and the type II receptor BMPR2. BMPR1A is a single-pass type I membrane protein and highly expressed in skeletal muscle. BMPR1A contains one GS domain and one protein protein kinase domain. BMPR1A is necessary for the extracellular matrix depostition by osteoblasts. BMPR1A can activate SMAD transcriptional regulators, binding with ligands. Defects in BMPR1A are a cause of juvenile polyposis syndrome, Cowden disease and hereditary mixed polyposis syndrome 2 (HMPS2).