Nature: Cancer cells betray their whereabouts when they evade the immune system

December 20, 2020 /--- -- Melanoma cells eventually lead to a deficiency of tryptophan, a key nutrient, as they bypass the immune system.
, unlike healthy cells, these cancer cells can continue to synthesize proteins to survive, but at a cost: they will be more easily detected by the immune system.
images from Nature, 2020, doi:10.1038/s41586-020-03054-1.
researchers led by Reuven Agami of the Netherlands Cancer Institute and Yardena Samuels of the Weizmann Institute of Science in Israel, in collaboration with the University of Oslo, Norway, presented the findings online on December 16, 2020 in the journal Nature, entitled "Anti-tumourmmunity immunity aber aber peprantide presentation in melanoma".
looking for weaknesses in cancer cells Cancer cells behave differently from healthy cells.
they adapt quickly, take greater risks than healthy cells, and try to survive in harsh environments that kill healthy cells.
but these things come at a price: they make mistakes and create new weaknesses.
these weaknesses are exactly what cancer researchers are trying to discover.
if healthy cells in our body lack a nutrient, the amino acid tryptophan found in food, they stop synthesized proteins.
cells can't survive without tryptophan.
If a protein-making plant in a cell ---rucleosome--- stumbles upon a coder encoding tryptophan (three adjacent bases make up a cocoon), they stop reading and synthesize until tryptophan is replenished.
the code, but in melanoma ---a kind of invasive skin cancer---, the RNA continues to read the mRNA sequence of cocoons: each cocoon corresponds to a specific amino acid.
is just the first base in which these cancer cells skip the cryptics corresponding to tryptophan.
, the reading box changed completely.
this is called a shifting.
this is like the easy-to-understand sentence "if still possible" becoming "Fst ill pos sib le", in other words, nonsense.
abnormal peptides in melanoma, cancer cells continue to synthesize proteins.
, however, these proteins are made from abnormal peptides based on miscoding.
melanoma cells continue to function, but at the cost of selling out their presence to T cells in the immune system.
melanoma cells present these abnormal protein fragments outside the cell, just as cells tend to do when dealing with foreign objects.
immunotherapy, the researchers speculate, paving the way for new types of immunotherapy.
T cells from healthy people can be trained to identify these foreign protein fragments.
, melanoma cells deplete their tryptophan stocks by circumventing the immune system.
to stop T-cells from acting fatally in tumors, melanoma cells produce an enzyme that synthesizes a substance that inhibits T-cells from killing cancer cells.
process, tryptophan is broken down, leading to a lack of nutrients.
tried to stop the enzyme with a targeted drug to improve the success rate of immunotherapy based on immunosuppression, which unexpectedly proved ineffective in clinical trials.
the effectiveness of this immunotherapy has not improved.
the researchers studied the mechanisms behind this clinical failure, they stumbled across coding and abnormal peptide production --- a finding that could pave the way for the development of new forms of immunotherapy.
think this flexibility in mRNA translation stimulates tumor growth and aggressive behavior, but it sacrifices the quality of the proteins that cancer cells produce when nutrients are scarce," Agami said.
" (Bioon.com) Reference: 1.Osnat Bartok et al. Anti-tumor immunity induces aberrant peptide presentation in melanoma. Nature, 2020, doi:10.1038/s41586-020-03054-1.2.Cancer cells circumvent immune system, but reveal themselves in the process。