Tumor

Integrins are a family of transmembrane proteins involved in diverse processes including cell adhesion, signal transduction, cell migration, and differentiation. They exist as heterodimers consisting of noncovalently linked alpha and beta subunits. Integrin complexes span the plasma membrane and link the cytoskeleton with the extracellular matrix. In mammals there are 18 alpha and 8 beta subunits that can assemble into 24 distinct integrin heterodimers with alternative splicing adding even more diversity.

The protein P2Y2 is a G-protein coupled metabotropic receptor that belongs to a larger family consisting of several receptor subtypes that each has a different pharmacological selectivity for various adenosine and uridine nucleotides. (This selectivity overlaps in some cases).

The SOX gene family encodes a group of highly conserved transcription factors defined by the presence of a conserved high motility group (HMG) DNA-binding domain. They are involved in embryonic development regulation and cell fate determination. All SOX proteins have a single HMG box and bind linear DNA in a sequence-specific manner, resulting in the bending of DNA through large angles. This bending opens the DNA helix for some distance, which may affect the binding and interactions of other transcription factors.

Notch1 is a member of the Notch family of Type 1 single-pass transmembrane proteins that share an extracellular domain of multiple epidermal growth factor-like (EGF) repeats. Notch family members play key roles in a variety of developmental processes via the regulation of cell fate. These processes include cell-fate determination, proliferation, and cell contact-dependent signaling. In Drosophila, notch interaction with its cell-bound ligands (delta, serrate) establishes a key development intercellular signaling pathway.

Ep-CAM is a monomeric transmembrane glycoprotein that is found exclusively on every epithelial cell membrane and a variety of epithelial carcinomas and cancer-initiating cells. It mediates calcium-independent cell-cell adhesion. Because Ep-CAM is overexpressed in a variety of human carcinomas it is both a valuable marker as well as a potential therapeutic target for human solid tumors. The adhesion properties of this molecule marker are dependent upon its two epidermal growth factor-like repeats within its extracellular domain coupled with a cysteine-poor region.

The thymidine synthetic nucleoside analogue bromodeoxyuridine (BrdU) has a long, colorful history of repeated use in molecular and cytokinetic studies, as detailed in reviews by Vanderlaan and Dolbeare (1,2).  Because BrDU is only incorporated into newly synthesized DNA in actively replicating S-phase cells, it allows for accurate and comprehensive quantitation of the pattern, rate, and progression of cell proliferation.

The c-Kit (CD117) proto-oncogene is a 145 kD receptor tyrosine kinase family closely related to platelet-derived growth factor receptor (PDGFR). It is a transmembrane receptor and the cellular homolog of the HZ4-feline sarcoma virus transforming gene (v-Kit). c-Kit is expressed on hematopoietic stem cells (multipotent hematopoietic stem cells, myeloid and/or erythroid lineage progenitors, and T-and B- cell precursors), mast cells, and acute myeloid leukemia (AML) cells. c-Kit regulates a variety of biological responses such as chemotaxis, cell proliferation, apoptosis, and adhesion.

The extracellular matrix (ECM) is the external framework found between individual cells that comprise higher order structures like tissues and organs. The ECM composition of vertebrates is dominated by a class of molecules known as collagens - each with unique features suited for a particular function and location. Collagen proteins are made up of three subunit polypeptides that vary in length. Through a unique repeated (Gly-X-Y) sequence, these components associate to form a structurally regular triple helix.

L-selectin is a member of the selectin family of glycoprotein adhesion and homing receptors that recognize sialyated carbohydrate groups and regulate lymphocyte-endothelial cell interactions. It is a type I transmembrane cell adhesion molecule (CAM) and is constitutively expressed on all classes of circulating leukocytes including lymphocytes (excluding memory T-cells), monocytes, and polymorphonuclear (PMN) cells.

GH is a member of the large family of growth factors that includes prolactin, placental lactogens, proliferins, and somatolactin. Additionally, GH is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland. Release of GH into the circulation is mediated by the concerted actions of the hypothalamic hormones-GH-releasing hormone (GHRH) and somatostatin (SST), as well as through signals from the periphery-ghrelin and leptin.