Proprotein Convertases In Gynecological Cancers

Gynecological cancers include neoplasias of internal female genital organs, mainly ovarian, endometrial and cervical tumors, and cancers of the external female genital structures. Current scientific evidence indicates that both up- and down-regulation of the expression of PCs are part of the multiple changes occurring in these gynecological tumors. Nevertheless, the physiological significance of this puzzling pattern of PC expression remains elusive. The fact that PCs can activate both pro- and anticarcinogenic substrates may indicate that the nature of the overexpressed substrates in certain cancer types could determine the final outcome; i.e., slowing or accelerating cancer development.

Proprotein convertases (PCs) are a family of proteases including PC1, PC2, Furin, PC4, PACE4, PC5, and PC7. These enzymes are involved in the maturation of many precursor proteins involved in the process of tumorigenesis and metastasis. Since their discovery, PCs were suggested as potential targets for anti-cancer therapy, and their activity was found to directly affect tumor cell proliferation, migration invasion, and the malignant phenotypes of tumor cells. Here, we discuss a number of previous and recent findings on the PCs features, their implication in the regulation of multiple cellular functions that impact on the invasive/metastatic potential of cancer cells, and their clinical relevance in cancer patients. Among the substrates of the proprotein convertases, various growth factors, their receptors, adhesion molecules, and proteases were identified. The PCs are inhibited by endogenous and exogenous inhibitors. To date, only pro7B2, a specific chaperone of PC2, and the granine-like precursor of neuroendocrine protein proSAAS, a selective ligand of PC1, have been identified as endogenous inhibitors of the PCs found in the regulated pathway. However, only PCs prosegments, several bioengineered inhibitors, peptides, and non-peptide compounds were found to inhibit the activity of the PCs found in the secretory pathway.

Gynecological cancers include neoplasias of internal female genital organs, mainly ovarian, endometrial and cervical tumors, and cancers of the external female genital structures. Current scientific evidence indicates that both up- and down-regulation of the expression of PCs are part of the multiple changes occurring in these gynecological tumors. Nevertheless, the physiological significance of this puzzling pattern of PC expression remains elusive. The fact that PCs can activate both pro- and anticarcinogenic substrates may indicate that the nature of the overexpressed substrates in certain cancer types could determine the final outcome; i.e., slowing or accelerating cancer development. The expression of PCs in gynecological cancers and the correlation of this expression with other markers may facilitate preventive and therapeutic interventions in at-risk populations. Several studies single out furin as the main PC overexpressed in ovarian and endometrial cancers. For instance, furin expression has been associated with five-year survival in ovarian cancer, and measurements of furin activity in cells obtained by lavage constitute a non-invasive diagnostic tool for endometrial cancer. The other ubiquitously expressed PCs, PC5, PACE4, and PC7 do not show any changes with respect to normal controls or are decisively silenced, as indicated by studies on PACE4 expression and regulation in both ovarian and endometrial tumors. PCs activate crucial substrates implicated in the progression of gynecological cancers, including adhesion molecules, metalloproteinases, and viral proteins. In the first place, furin, and possibly the other PCs, process both E- and N-cadherin. Processing of these molecules results in variations of cell adhesiveness. The pattern of expression of N- and especially E-cadherin varies during tumor development, as well as in the stages of either epithelial to mesenchymal or mesenchymal to epithelial transitions. E-cadherin is up-regulated during initial steps in ovarian tumor development, whereas N-cadherin follows a more complex expression pattern. Nevertheless, cadherin processing requires fully functional PC activity, a feature that may be explored for future therapeutics applications. Furthermore, PCs drive the activation of metalloproteinases, especially the membrane-type metalloproteases MMP-14 and MMP-15, and also possibly MMP-9. The activity of these metalloproteases promotes the invasion into the omentum and other peritoneal structures, facilitating the degradation of collagens and other extracellular components. Finally, the role of furin in enabling papilloma virus infection, one of the main etiological factors in the development of exocervical cancer, and possibly vaginal and vulvar carcinoma, cannot be overemphasized. These experimental evidences suggest that careful targeting of PCs in gynecological cancer may represent a feasible strategy to deter tumor progression.

Proprotein convertases (PCs) are a family of proteases including PC1, PC2, Furin, PC4, PACE4, PC5, and PC7. These enzymes are involved in the maturation of many precursor proteins involved in the process of tumorigenesis and metastasis. Since their discovery, PCs were suggested as potential targets for anti-cancer therapy, and their activity was found to directly affect tumor cell proliferation, migration invasion, and the malignant phenotypes of tumor cells. Here, we discuss a number of previous and recent findings on the PCs features, their implication in the regulation of multiple cellular functions that impact on the invasive/metastatic potential of cancer cells, and their clinical relevance in cancer patients. Among the substrates of the proprotein convertases, various growth factors, their receptors, adhesion molecules, and proteases were identified. The PCs are inhibited by endogenous and exogenous inhibitors. To date, only pro7B2, a specific chaperone of PC2, and the granine-like precursor of neuroendocrine protein proSAAS, a selective ligand of PC1, have been identified as endogenous inhibitors of the PCs found in the regulated pathway. However, only PCs prosegments, several bioengineered inhibitors, peptides, and non-peptide compounds were found to inhibit the activity of the PCs found in the secretory pathway.

Proprotein Convertases—Advances in Research and Application: 2012 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Proprotein Convertases. The editors have built Proprotein Convertases—Advances in Research and Application: 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Proprotein Convertases in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Proprotein Convertases—Advances in Research and Application: 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Stem cells have great potential in regenerative medicine and tissue injury. Regulation of stem cell homeostasis in a 3D microenvironment is controlled by the niche components that influence stem cell fate, regulation, and function. It is therefore necessary to understand the mechanisms of cell–cell interaction, molecular cross talk between stem cells and their extracellular matrix (ECM) environment. The adhesion molecules play a pivotal role in establishing the cell–cell contact and subsequent integration with the ECM. This understanding is the basis for establishing design criteria for biomimetic. The integrated approach by biologists, material science engineers, biomedical engineers, and clinicians is the key in the development of tissue engineered constructs for effective translation to clinics.

The ATP-binding cassette (ABC) transporter genes are ubiquitous in the genomes of all vertebrates so far studied. The human ABC transporter superfamily contains 48 genes, subdivided into 7 subfamilies ranging from A to G (based on sequence homology of their nucleotide binding domains). The ABC proteins encoded by these genes are ATP-driven transmembrane pumps, some of which possess the capacity to efflux harmful toxic substances and therefore play a key role in xenobiotic defense. ABC proteins have been evolutionarily conserved from bacteria to humans and multiple gene duplication and deletion events in the ABC genes indicate that the process of gene evolution is still ongoing. Polymorphisms and variations in these genes are linked to variations in expression, function, drug disposition, and drug response. Single nucleotide polymorphisms (SNPs) in these genes could be markers of individual risk for adverse drug reactions or susceptibility to complex diseases. The pharmacogenetics of this unique family of transporters is still under study; however, in the context of human health, it is a well-known fact that variations in these transporters are the underlying cause for several human diseases including cystic fibrosis, Pseudoxanthoma elasticum (PXE), and X-linked adenoleukodystrophy (X-ALD).

Endometrial Cancer: New Insights for the Healthcare Professional / 2012 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Endometrial Cancer. The editors have built Endometrial Cancer: New Insights for the Healthcare Professional / 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Endometrial Cancer in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Endometrial Cancer: New Insights for the Healthcare Professional / 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.