Cancer

AP-endonuclease (APE1/Ref-1) is an essential multifunctional protein involved in the repair of oxidative DNA damage as well as in transcriptional regulation in tumor cells. It functions as an apurinic/apyrimidinic (AP) endodeoxyribonuclease in the DNA base excision repair (BER) pathway of DNA lesions, and may also play a role in the epigenetic regulation of gene expression and the protection from granzymes-mediated cellular repair leading to cell death.

The genetic disorder known as Fanconi anemia (FANC) is a heterogeneous, autosomal-recessive cancer susceptibility condition characterized by a wide array of symptoms. These include congenital malformations, progressive bone marrow failure, DNA-damage hypersensitivity, and genome instability. The protein FANCD2 is a subunit of the protein complex involved in cellular resistance to DNA cross-linking and DNA synthesis arrest triggered by ionizing radiation (IR).

Bone morphogenetic proteins such as GDF15 belong to the transforming growth factor-beta (TGFB) family that directs tissue differentiation and maintenance. GDF15 appears to be involved in a variety of physiological processes such as pregnancy, injury and inflammation, and apoptosis. Evidence suggests GDF15 is a marker for metastasis.

The NUT gene is found on chromosome 15q14 and encodes for the NUT protein which is a key component of the RNA polymerase II Mediator complex. This multi-subunit assembly is required for all RNA pol II-dependent transcriptional activation, coordinating both nuclear and mitochondrial gene transcription. The complex also includes pol II, and transcription factors TFIIA-F. It serves as a central scaffold within the pre-initiation complex (PIC) responsible for converting biological stimuli (in the form of transcription factors) into gene expression responses.

Nitric oxide (NO) is an inorganic, gaseous, and reactive free radical that acts as a biologic mediator in processes such as neurotransmission, vasorelaxation, and cytotoxicity. In addition, it has antimicrobial and anti-tumoral activities. NO production is mediated by members of the nitric oxide synthase (NOS) family. The NOS enzyme catalyzes the oxidization of L-arginine into L-citrulline and NO.  Several subtypes have been identified: two constitutive isoforms (type I brain/neuronal NOS, and type III endothelial) and one inducible isoform (iNOS, or type II).

IL-6 is an immunoregulatory cytokine that functions in inflammation and B-cell maturation. It was originally identified as a B-cell differentiation factor. It is primarily made at sites of acute and chronic inflammation, where it is secreted into serum and induces a transcriptional inflammatory response through the cell surface assembly of interleukin-6 alpha receptor (IL-6R, alpha) and the signaling receptor gp130.

The protein CD11b has been implicated in the various adhesion-related interactions of cells such as monocytes, macrophages, natural killer (NK) cells, and granulocytes. It is part of a heterodimer that consists of CD11b and CD18. It also modulates the uptake of complement-coated particles within the cell. It is commonly used as a microglial marker in tissues derived from the nervous system.

Breast cancer 1, early onset (BRCA1) is a well-known tumor suppressor gene that was originally discovered due to its link with early-onset breast and ovarian cancer in women. The BRCA1 protein contains the following domains: RING finger, RAD51-interaction, and BRCT (BRCA1 C-terminus). The N-terminus RING domain enables binding to several proteins - including BARD1 (BRCA1-associated RING domain protein) - allowing the formation of heterodimers. The RING finger is important for tumor suppressor activity. The RAD51-interaction domain is involved in DNA double-stranded break (DSB) repair.

The cluster of differentiation 4 (CD4) protein is a surface, type I membrane-embedded glycoprotein that is found on a wide range of cells: T-lymphocytes, B-cells, macrophages, granulocytes, and developmentally-dependent regions specific to the brain. It interacts with major histocompatibility complex (MHC) class II anti-genes, serves as the human immunodeficiency virus (HIV) receptor, and can initiate/augment early phase T-cell activation.  In immune-mediated and central nervous system (CNS) infectious diseases, CD4 indirectly mediates neuronal damage.

The enzyme, aromatase, belongs to cytochrome P450 family of monooxygenases known for their key role in drug catabolism and cholesterol/steroid synthesis. Aromatase uses a heme-group as a co-factor to catalyze the formation of aromatic C18 estrogens from C19 androgens. This conversion includes that of testosterone into estradiol as well as androstenedione to estrone. Aromatase is a peripheral membrane protein.