Axin-2, also known as axin-like protein (Axil), axis inhibition protein 2 (AXIN2), or conductin, is a protein that in humans is encoded by the AXIN2 gene. [5] [6]
The Axin-related protein, Axin2, presumably plays an important role in the regulation of the stability of beta-catenin in the Wnt signaling pathway, like its rodent homologs, mouse conductin/rat axil. In mouse, conductin organizes a multiprotein complex of APC (adenomatous polyposis of the colon), beta-catenin, glycogen synthase kinase 3-beta, and conductin, which leads to the degradation of beta-catenin. [6] The AXIN proteins attract substantial interest in cancer research as AXIN1 and AXIN2 work synergistically to control pro-oncogenic β-catenin signaling. Importantly, activity in the β-catenin destruction complex can be increased by tankyrase inhibitors and are a potential therapeutic option to reduce the growth of β-catenin-dependent cancers. [7]
The deregulation of beta-catenin is an important event in the genesis of a number of malignancies. The AXIN2 gene has been mapped to 17q23-q24, a region that shows frequent loss of heterozygosity in breast cancer, neuroblastoma, and other tumors. Mutations in this gene have been associated with colorectal cancer with defective mismatch repair. [6]
The most critical events of teeth, lip and palate formation occur almost concurrently. Hypodontia, defined as the congenital lack of one or more permanent teeth, is the most common dental abnormality found in humans and affects approximately 20% of the population worldwide. [8] AXIS inhibition protein 2 (AXIN2) gene polymorphic variants may be associated with both hypodontia and oligodontia (characterized by the lack of six or more permanent teeth). [9] [10] Mutations of this gene have been found in individuals with colorectal carcinomas and liver tumors. [11]
An AXIN2 mutation (1966C>T) detected in a Finnish family was associated with both tooth agenesis and colon neoplasia. A second family is described from Michigan in 2011, with members describing severe oligodontia, sparse hair, and hundreds of colons polyps. Another family was found by the Mayo Clinic in 2019. In essence, the mutation seems to disrupt tooth development early in life and later contributes to the emergence of polyps and eventually colon cancer, an observation that suggests that the lack of permanent teeth may be an indicator of colon cancer susceptibility. [9] Dentists may at the very least need to remain aware of the possible association, to be able to detect such cases of tooth agenesis and forward the patient to more complete genetic diagnostic examinations. This is a simple example of how molecular genetic discoveries today interact with traditional disciplines (Longtin, 2004).
The Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt is a portmanteau created from the names Wingless and Int-1. Wnt signaling pathways use either nearby cell-cell communication (paracrine) or same-cell communication (autocrine). They are highly evolutionarily conserved in animals, which means they are similar across animal species from fruit flies to humans.
Catenins are a family of proteins found in complexes with cadherin cell adhesion molecules of animal cells. The first two catenins that were identified became known as α-catenin and β-catenin. α-Catenin can bind to β-catenin and can also bind filamentous actin (F-actin). β-Catenin binds directly to the cytoplasmic tail of classical cadherins. Additional catenins such as γ-catenin and δ-catenin have been identified. The name "catenin" was originally selected because it was suspected that catenins might link cadherins to the cytoskeleton.
Adenomatous polyposis coli (APC) also known as deleted in polyposis 2.5 (DP2.5) is a protein that in humans is encoded by the APC gene. The APC protein is a negative regulator that controls beta-catenin concentrations and interacts with E-cadherin, which are involved in cell adhesion. Mutations in the APC gene may result in colorectal cancer and desmoid tumors.
Catenin beta-1, also known as β-catenin (beta-catenin), is a protein that in humans is encoded by the CTNNB1 gene.
Transcription factor 7-like 2 , also known as TCF7L2 or TCF4, is a protein acting as a transcription factor that, in humans, is encoded by the TCF7L2 gene. The TCF7L2 gene is located on chromosome 10q25.2–q25.3, contains 19 exons. As a member of the TCF family, TCF7L2 can form a bipartite transcription factor and influence several biological pathways, including the Wnt signalling pathway.
Beta-catenin-interacting protein 1 is a protein that is encoded in humans by the CTNNBIP1 gene.
Axin-1 is a protein that in humans is encoded by the AXIN1 gene.
Frizzled-7(Fd-7) is a protein that in humans is encoded by the FZD7 gene.
Segment polarity protein dishevelled homolog DVL-1 is a protein that in humans is encoded by the DVL1 gene.
Secreted frizzled-related protein 1, also known as SFRP1, is a protein which in humans is encoded by the SFRP1 gene.
Protein Wnt-3a is a protein that in humans is encoded by the WNT3A gene.
Segment polarity protein dishevelled homolog DVL-3 is a protein that in humans is encoded by the DVL3 gene.
B-cell CLL/lymphoma 9 protein is a protein that in humans is encoded by the BCL9 gene.
Mouse models of colorectal cancer and intestinal cancer are experimental systems in which mice are genetically manipulated, fed a modified diet, or challenged with chemicals to develop malignancies in the gastrointestinal tract. These models enable researchers to study the onset, progression of the disease, and understand in depth the molecular events that contribute to the development and spread of colorectal cancer. They also provide a valuable biological system, to simulate human physiological conditions, suitable for testing therapeutics.
Wingless-type MMTV integration site family, member 2, also known as WNT2, is a human gene.
Dishevelled (Dsh) is a family of proteins involved in canonical and non-canonical Wnt signalling pathways. Dsh is a cytoplasmic phosphoprotein that acts directly downstream of frizzled receptors. It takes its name from its initial discovery in flies, where a mutation in the dishevelled gene was observed to cause improper orientation of body and wing hairs. There are vertebrate homologs in zebrafish, Xenopus (Xdsh), mice and humans. Dsh relays complex Wnt signals in tissues and cells, in normal and abnormal contexts. It is thought to interact with the SPATS1 protein when regulating the Wnt Signalling pathway.
The TCF/LEF family is a group of genes that encode transcription factors which bind to DNA through a SOX-like high mobility group domain. They are involved in the Wnt signaling pathway, particularly during embryonic and stem-cell development, but also had been found to play a role in cancer and diabetes. TCF/LEF factors recruit the coactivator beta-catenin to enhancer elements of genes they target. They can also recruit members of the Groucho family of corepressors.
Naked cuticle 1 (NKD1) is a human gene that encodes the protein Nkd1, a member of the Naked cuticle (Nkd) family of proteins that regulate the Wnt signaling pathway. Insects typically have a single Nkd gene, whereas there are two Nkd genes, Nkd1 and Nkd2, in most vertebrates studied to date. Nkd1 binds to the Dishevelled (Dvl) family of proteins. Specific truncating NKD1 mutations identified in DNA mismatch repair deficient colon cancer that disrupt Nkd1/Dvl binding implicate these mutations as a cause of increased Wnt signaling in a subset of human colon cancers, the majority of which have increased Wnt signaling due to mutations the adenomatous polyposis coli (APC), AXIN2, or rarely the beta-catenin genes.
Ring finger protein 43 is a protein that in humans is encoded by the RNF43 gene.
hPG80 refers to the extracellular and oncogenic version of progastrin. This name first appeared in a scientific publication in January 2020. Until that date, scientific publications only mention 'progastrin', without necessarily explicitly specifying whether it is intracellular or extracellular in the tumor pathological setting.