CTSK and PLAU as Prognostic Biomarker and Related to Immune Infiltration in Pancreatic Cancer: Evidence from Bioinformatics Analysis and qPCR

Table 2

Function of 12 hub genes.

No.	Gene symbol	Full name	Function
1	COL11A1	Collagen type XI alpha-1 chain	This gene encodes one of the two alpha chains of type XI collagen, a minor fibrillar collagen. Type XI collagen is a heterotrimer, but the third alpha chain is a posttranslationally modified alpha-1 type II chain. Mutations in this gene are associated with type II Stickler syndrome and with Marshall syndrome. A single-nucleotide polymorphism in this gene is also associated with susceptibility to lumbar disc herniation. Multiple transcript variants have been identified for this gene
2	ASPM	Abnormal spindle-like microcephaly-associated protein	Involved in mitotic spindle regulation and coordination of mitotic processes. The function of regulating microtubule dynamics at spindle poles including spindle orientation, astral microtubule density, and poleward microtubule flux seems to depend on the association with the katanin complex formed by KATNA1 and KATNB1. Enhances the microtubule lattice severing activity of KATNA1 by recruiting the katanin complex to microtubules. Can block microtubule minus-end growth, and reversely, this function can be enhanced by the katanin complex
3	CTSK	Cathepsin K	Thiol protease is involved in osteoclastic bone resorption and may participate partially in the disorder of bone remodeling. Displays potent endoprotease activity against fibrinogen at acid pH. May play an important role in extracellular matrix degradation. Involved in the release of thyroid hormone thyroxine (T4) by limited proteolysis of TG/thyroglobulin in the thyroid follicle lumen
4	OAS1	2-5-Oligoadenylate synthase 1	Interferon-induced, dsRNA-activated antiviral enzyme which plays a critical role in cellular innate antiviral response
5	PLAU	Urokinase-type plasminogen activator	Specifically cleaves the zymogen plasminogen to form the active enzyme plasmin
6	EPHA4	Ephrin type-A receptor 4	Receptor tyrosine kinase, which binds membrane-bound ephrin family ligands residing on adjacent cells, leads to contact-dependent bidirectional signaling into neighboring cells. The signaling pathway downstream of the receptor is referred to as forward signaling, while the signaling pathway downstream of the ephrin ligand is referred to as reverse signaling. Highly promiscuous, it has the unique property among Eph receptors to bind and to be physiologically activated by both GPI-anchored ephrin-A and transmembrane ephrin-B ligands including EFNA1 and EFNB3. Upon activation by ephrin ligands, it modulates cell morphology and integrin-dependent cell adhesion through regulation of the Rac, Rap, and Rho GTPases activity. Plays an important role in the development of the nervous system by controlling different steps of axonal guidance including the establishment of the corticospinal projections. May also control the segregation of motor and sensory axons during neuromuscular circuit development. In addition to its role in axonal guidance, it also plays a role in synaptic plasticity. Activated by EFNA1, it phosphorylates CDK5 at “Tyr-15” which in turn phosphorylates NGEF, regulating RHOA and dendritic spine morphogenesis. The nervous system also plays a role in repair after injury, preventing axonal regeneration, and in angiogenesis, which plays a role in central nervous system vascular formation. Additionally, its promiscuity makes it available to participate in a variety of cell-cell signaling, regulating, for instance, the development of the thymic epithelium. During development, the cochlear organ of Corti regulates pillar cell separation by forming a ternary complex with ADAM10 and CADH1 which facilitates the cleavage of CADH1 by ADAM10 and disruption of adherens junctions
7	ITGA3	Integrin alpha-3	Integrin alpha-3/beta-1 is a receptor for fibronectin, laminin, collagen, epiligrin, thrombospondin, and CSPG4. Integrin alpha-3/beta-1 provides a docking site for FAP (seprase) at invadopodia plasma membranes in a collagen-dependent manner and hence may participate in the adhesion, formation of invadopodia, and matrix degradation processes, promoting cell invasion. Alpha-3/beta-1 may mediate with LGALS3 the stimulation by CSPG4 of endothelial cell migration
8	RUNX2	Runt-related transcription factor 2	Transcription factor involved in osteoblastic differentiation and skeletal morphogenesis
9	CXCL5	C-X-C motif chemokine 5	Involved in neutrophil activation. In vitro, ENA-78(8-78) and ENA-nnn(9-78) show a threefold higher chemotactic activity for neutrophil granulocytes
10	FAM150B	Family with sequence similarity 150 member B	Enables receptor signaling protein tyrosine kinase activator activity and receptor tyrosine kinase binding activity. Involved in positive regulation of the ERK1 and ERK2 cascades, positive regulation of the ERK5 cascade, and positive regulation of neuron projection development. Predicted to be located in an extracellular region
11	CPA2	Carboxypeptidase A2	Similar to that of carboxypeptidase A (EC 3.4.17.1), but with a preference for bulkier C-terminal residues
12	GABRP	Gamma-aminobutyric acid receptor subunit pi	GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel. In the uterus, the function of the receptor appears to be related to tissue contractility. The binding of this pI subunit with other GABA(A) receptor subunits alters the sensitivity of recombinant receptors to modulatory agents such as pregnanolone