CLASS 1-TERMS Flashcards
What ctDNA is?
Circulating tumor DNA (ctDNA) is found in the bloodstream and refers to DNA that comes from cancerous cells and tumors. Most DNA is inside a cell’s nucleus. As a tumor grows, cells die and are replaced by new ones. The dead cells get broken down and their contents, including DNA, are released into the bloodstream. ctDNA are small pieces of DNA, usually comprising fewer than 200 building blocks (nucleotides) in length.
What is cfDNA?
Cell-free DNA (or cfDNA) refers to all non-encapsulated DNA in the blood stream. A portion of that cell-free DNA originates from a tumor clone and is called circulating tumor DNA (or ctDNA). cfDNA are nucleic acid fragments that enter the bloodstream during apoptosis or necrosis
What is tumor mutational burden?
The total number of mutations (changes) found in the DNA of cancer cells. Knowing the tumor mutational burden may help plan the best treatment. For example, tumors that have a high number of mutations appear to be more likely to respond to certain types of immunotherapy.
What platelets are?
(ΑΙΜΟΠΕΤΑΛΕΙΑ)
Platelets are the cells that circulate within our blood and bind together when they recognize damaged blood vessels,” says Marlene Williams, M.D., director of the Coronary Care Unit at Johns Hopkins Bayview Medical Center. “When you get a cut, for example, the platelets bind to the site of the damaged vessel, thereby causing a blood clot. There’s an evolutionary reason why they’re there. It’s to stop us from bleeding.”
What is the function of endothelial cells?
Endothelial cells form a single cell layer that lines all blood vessels and regulates exchanges between the bloodstream and the surrounding tissues. Signals from endothelial cells organize the growth and development of connective tissue cells that form the surrounding layers of the blood-vessel wall.
What CAFs are?
Cancer-associated fibroblasts (CAFs) are a group of activated fibroblasts with significant heterogeneity and plasticity in the tumor microenvironment. They secrete a variety of active factors to regulate tumor occurrence, development, metastasis, and therapeutic resistance. Although most studies suggest that CAFs have significant tumor-promoting functions, some evidence indicates that they may have certain tumor-suppressive functions in the early stage of tumors.
What MDA-MB-231 is?
MDA-MB-231 is a highly aggressive, invasive and poorly differentiated triple-negative breast
cancer (TNBC) cell line as it lacks oestrogen receptor (ER) and progesterone receptor (PR)
expression, as well as HER2 (human epidermal growth factor receptor 2) amplification2,3.
Similar to other invasive cancer cell lines, the invasiveness of the MDA-MB-231 cells is
mediated by proteolytic degradation of the extracellular matrix
What is MCF-7?
It is ER-positive and progesterone receptor (PR)-positive (8) and belongs to the luminal A molecular subtype (2). MCF-7 is a poorly-aggressive and non-invasive cell line (9), normally being considered to have low metastatic potential
What makes an antibody monoclonal, polyclonal, or recombinant?
A polyclonal antibody is a heterogeneous mixture of antibodies derived from distinct B- lymphocyte populations that detect different epitopes within the same immunogen. Polyclonal antibodies are typically produced in rabbits but can also be made in ungulates (sheep, goat, horse, etc.), rodents, and chickens, depending on the researchers’ need. Production of polyclonals typically involves collection of blood from the immunized animal, isolation of the immunoglobulin fraction, and affinity purification to remove non-specific antibody populations. Rabbits offer significant advantages over other species due to their larger antibody diversity and ability to generate immune responses to a wide range of antigens including small molecules and peptides with or without post-translational modifications.
A monoclonal antibody is a homogeneous antibody derived from a single B-cell clone which detects a single epitope within the immunogen. All monoclonal antibodies begin as a pool of polyclonal antibodies but are isolated through a selection or cloning process to identify and expand the desired monovalent clone. Monoclonal antibodies are typically produced from rodent hosts, rabbits and camelids, and are produced via a variety of methods depending on the species and type of antibody desired (as detailed below). Traditionally, monoclonal antibodies are generated via stable clones of immortalized B-cells either by injecting and collecting ascites from a mouse or culturing the antibody expressing B-cells and collecting the supernatant. More recently, newer techniques have enabled recombinant cloning of the immunoglobulin heavy and light chain genes from immunoreactive B-cells for expression and production of recombinant monoclonal antibodies in mammalian cell lines.
PD-L1 και Καρκίνος
Tα καρκινικά κύτταρα έχουν την ικανότητα να ξεφεύγουν των Τ-κυττάρων εκφράζοντας μια πρωτεΐνη που λέγεται PD-L1 και η οποία λειτουργεί ως «στοπ» και αδρανοποιεί τα Τ-κύτταρα.
Μία προσέγγιση για την καταπολέμηση του καρκίνου είναι η καταστολή της πρωτεΐνης PD-L1, μέσω της οποίας τα καρκινικά κύτταρα παύουν να αδρανοποιούν τα Τ-κύτταρα μέσω των υποδοχέων PD-1 και B7.1. Ο στόχος της ανοσοθεραπείας είναι να αυξηθεί η δραστηριότητα του ανοσοποιητικού συστήματος, ώστε να προκληθεί μια πιο αποτελεσματική αντικαρκινική αντίδραση.
What is CTLA-4?
CTLA-4 or CTLA4 (cytotoxic T-lymphocyte-associated protein 4), also known as CD152 (cluster of differentiation 152), is a protein receptor that functions as an immune checkpoint and downregulates immune responses. CTLA-4 is constitutively expressed in regulatory T cells but only upregulated in conventional T cells after activation – a phenomenon which is particularly notable in cancers.[5] It acts as an “off” switch when bound to CD80 or CD86 on the surface of antigen-presenting cells.
What is Vimentin?
Vimentin is a structural protein that in humans is encoded by the VIM gene. Its name comes from the Latin vimentum which refers to an array of flexible rods.[5]
Immunofluorescence staining of HeLa Cells with antibody to reveal vimentin containing intermediate filaments in green and antibody to LAMP1 to reveal lysosomes in red. Nuclear DNA is seen in blue. Antibodies and image courtesy EnCor Biotechnology Inc.
Vimentin is a type III intermediate filament (IF) protein that is expressed in mesenchymal cells. IF proteins are found in all animal cells[6] as well as bacteria.[7] Intermediate filaments, along with tubulin-based microtubules and actin-based microfilaments, comprises the cytoskeleton. All IF proteins are expressed in a highly developmentally-regulated fashion; vimentin is the major cytoskeletal component of mesenchymal cells. Because of this, vimentin is often used as a marker of mesenchymally-derived cells or cells undergoing an epithelial-to-mesenchymal transition (EMT) during both normal development and metastatic progression.
What is detyrosination?
Detyrosination is a form of posttranslational modification that occurs on alpha-tubulin.[1] It consists of the removal of the C-terminal tyrosine to expose a glutamate at the newly formed C-terminus. Tubulin polymers, called microtubules, that contain detyrosinated alpha-tubulin are usually referred to as Glu-microtubules while unmodified polymers are called Tyr-microtubules.
How m30 antibody works?
During apoptosis, vital intracellular proteins are cleaved. The proteases that mediate this process are called caspases (Cysteinyl-aspartic acid proteases). Caspases are expressed as zymogenes, which are activated by different apoptosis inducers. Once activated, a single caspase activates a cascade of caspases. Until recently, cytokeratins, in particular cytokeratin 18 (CK18), were not known to be affected by early events of apoptosis. Recently, it has been shown that the M30 antibody recognizes a specific caspase-cleavage site within cytokeratin 18, which is not detectable in native CK18 of normal cells. Consequently, the M30 CytoDEATH antibody is a unique tool for the easy and reliable determination of very early apoptotic events in single cells and tissue sections.
What is the normal function of ER and what happens in tumor formation?
ER activation in breast and uterus enhances cell proliferation which is necessary for growth and maintenance of tissues. When the response to estrogens by the endocrine system is deregulated, ER activation might eventually result in tumor formation.
Τί είναι η Χρωματομετρική Μέθοδος MTT?
Η χρωματομετρική μέθοδος ΜΤΤ, όπως περιγράφηκε πρώτη φορά χρησιμοποιήθηκε με ορισμένες τροποποιήσεις ως μέθοδος ποσοτικού
προσδιορισμού των πολλαπλασιαζόμενων κυττάρων in vitro. Η μέθοδος είναι
απλή, γρήγορη και επαναλήψιμη και χρησιμοποιείται ευρέως ως προκαταρκτική
μέθοδος ελέγχου δράσης νέων ουσιών. Βασίζεται στην ικανότητα των ζωντανών
και μεταβολικά ενεργών κυττάρων να μεταβολίζουν το άλας τετραζολίου MTT, 3-
(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, προς
έγχρωμους αδιάλυτους κρυστάλλους φορμαζάνης, κυρίως μέσω των
εξαρτώμενων από NAD(P)H αφυδρογονασών των μιτοχονδρίων ή/και του κυτταροπλάσματος.
Με διάλυση των κρυστάλλων φορμαζάνης και μέτρηση της απορρόφησης του
διαλύματος προσδιορίζεται ο αριθμός των κυττάρων με βάση πρότυπη καμπύλη
βαθμονόμησης.
Τί είναι φθορισμός;
Φθορισμός ονομάζεται η εκπομπή φωτός από μια ουσία
που έχει απορροφήσει φως ή αλλου είδους
ηλεκτρομαγνητική ακτινοβολία.
* Στις περισσότερες περιπτώσεις που αφορούν βιολογικές
παρατηρήσεις, το εκπεμπόμενο φως φθορισμού έχει
μεγαλύτερο μήκος κύματος, και άρα μικρότερη ενέργεια
σε σχέση με την απορροφούμενη ακτινοβολία.
