GFs-Cancer - Growth factors and Cancer How an organism...

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Growth factors and Cancer How an organism communicate with its surroundings ? How a cell talk or communicate with its surroundings ? How a pancreatic cell communicate with high glucose in the blood? How cell- cell communication occurs? How an epithelial cell communicate and coordinate with a stoma cell in a tissue?
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Signal Transduction Cell-to-cell communication requires signal transduction Growth factors (GFs) are small proteins or peptides that are released by some cell types and make their way through intercellular space and eventually impinge on yet other cell types, carrying with them specific biological messages. How this cell- cell communication decision is made? Decision about growth vs no-growth must be made for the welfare of the entire tissue and whole organism , not for the benefit of its individual component cells. This weighty decision can be undertaken only after the consultation with other cells within the tissue. These neighbors may provide a particular cell with GFs that stimulate its proliferation or release growth-inhibitory factors that discourage it.
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Autocrine signaling- acting on their own cells where they are synthesized Kaposi sarcoma cells express PDGF, TGF-B, IGF-1, Ang2, CXCL11 ald also its receptors In SCLC- TGF-a, SCF, IGF Paracrine signaling- acting on surrounding cells in a tissue E.g. Synthesized in epithelial cells but acting on stroma Endocrine Signaling- acting on another tissue via circulation E.g: E2 is produced in ovaries but act on MG Type of signaling
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EGF EGFR Breast cancer, head and neck
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GF receptor’s (GF-R)
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Different GFs and their action
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GF signaling: Receptor Firing dimerisation transphosphorylation Recruitment of adaptor proteins Kinase activation cytoskeleton structural changes transcription factor phosphorylation nuclear translocation activation of transcription immediate early genes delayed early genes Phenotype ( proliferation, migration, growth, apoptosis, adhesion) ***
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GF signaling: Receptor Firing
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Phopshorylation 1. Catalytic cleft of protein will be obstructed by a loop of protein, phosphorylation cause to swing this loop out of the way providing catalytic cleft with direct contact with substarte 1. Also makes other tyrosine sites to be pho. Located in the cytoplamsic domain.
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EGFR-dimerisation
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GF signaling
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GF signaling Adaptor protein Grb2 is coupled to the guanine nucleotide releasing factor, SOS
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EGF receptor (EGF-R) This family is comprised by transmembrane proteins that form part of the tyrosine kinases receptor proteins which are activated by different kinds of ligands. E.g.EGF, TGF alpha, Neuregulin . All the receptor tyrosine kinases share the same protein structure with an extracellular binding domain, a transmembrane domain and an intracellular domain where the catalytic domain is located. The autophosphorylation of tyrosine residues outside the catalytic domain stabilises the receptor in the active conformation and recruit different proteins required for signalling. Once the ligand binds the receptor and the molecule is phosphorylated it can switch on
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GFs-Cancer - Growth factors and Cancer How an organism...

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