Exam 3: Cancer III Flashcards
(retro)viruses introduce
genomic instability; an additional way to introduce instability in genomes
retroviruses cause cancer by (2)
- mutating and rearranging proto-oncogenes
2. inserting strong promoters near proto-oncogenes (overexpression)
why might a virus be associated with a specific type of cancer? if it is inserting at random in the genome, why does that lead to one type of cancer?
critical word is: if. a virus has certain repeated sequences in it’s genetic code and our genome has similar sequences in parts of it. similarity in those regions of our genome and viral sequences makes a virus more likely to insert in those regions. virus is finding the parts of our genome that is more conducive to its integration and those parts of the genome contain genes that promote cervical, penile, and vulvar cancers.
monoclonal antibodies production
take a protein (cell surface protein on lymphoma) you want to develop ab against, make lots of it, and inject in an animal. animal creates abs and take their spleen cells and fuse them w. myeloma cells and convert them into immortalized cells and purify the cells that make mass amts of abs and insert into humans
monoclonal antibodies target _
cancer cell specific antigens
monoclonal antibodies induce _
an immunological response against the target cancer cell
what can be coupled to an antibody
a toxin, radioisotope, cytokine or ther active conjugate
antibody therapy for cancer: direct tumor cell killing can be elicited by
receptor agonist activity, such as an antibody binding to a tumor cell surface receptor and activating it
antibody therapy for cancer: direct tumor cell killing activation leads to
apoptosis
antibody therapy for cancer: direct tumor cell killing can also be mediated by
receptor agonist activity, such as an antibody binding to a cell surface receptor and blocking dimerization, kinase activation and downstream signaling, leading to reduced proliferation and apoptosis
antibody therapy for cancer: immune-mediated tumor killing can be carried out by
the induction of phagocytosis, complement activation, antibody-dependent cellular cytotoxicity, genetically modified T cells etc w/ T cells
antibody therapy for cancer: vascular and stromal cell ablation can be induced by
vasculature receptor antagonism or ligand trapping, stromal cell inhibition; MAC, MHC, NK
what type of drug is rituximab
chimeric monoclonal antibody
mode of action for rituximab
targets protein CD20 for elimination; these cells are found on the surface of immune system B cells
rituximab is used to treat
treat diseases which are characterized by excessive numbers of B cells, overactive B cells, or dysfunctional B cells ie lymphomas, leukemias, transplant rejection, and autoimmune disorders
ADCC
a rituximab proposed mech: attracts natural killer cells, T cells and macrophages (recognizing and killing antibody-labeled target cells, leading to cell lysis)
CDC
a rituximab proposed mech: binding of the antibody recruits complement proteins, which punch holes in the cell membrane, flooding the cell and leading to cell lyisis
a rituximab proposed mech: apoptosis
binding of the antibody signals the cell to self-destruct
cancer immunotherapy
the science of mobilizing the immune system to kill cancer
researchers are racing to expand the use of immunotherapy to benefit more cancer patients but it remains unclear why
only a subset of individuals respond to treatment and how to better achieve sustained remissions