'Completely unexpected' increased WNT production
The researchers observed up to 30-fold increases in WNT production – a finding that was "completely unexpected," Nelson said. The WNT family of genes and proteins plays an important role in normal development and also in the development of some cancers but, until now, was not known to play a significant role in treatment resistance.
This discovery suggests that finding a way to block this treatment response in the tumor microenvironment may improve the effectiveness of therapy.
"Cancer therapies are increasingly evolving to be very specific, targeting key molecular engines that drive the cancer rather than more generic vulnerabilities, such as damaging DNA. Our findings indicate that the tumor microenvironment also can influence the success or failure of these more precise therapies." In other words, the same cancer cell, when exposed to different "neighborhoods," may have very different responses to treatment.
The major clinical reason that chemotherapy ultimately fails in the face of advanced cancer, Nelson said, is because the doses necessary to thoroughly wipe out the cancer would also be lethal to the patient.
"In the laboratory we can 'cure' most any cancer simply by giving very high doses of toxic therapies to cancer cells in a petri dish. However, in people, these high doses would not only kill the cancer cells but also normal cells and the host," he said.
Therefore, treatments for common solid tumors are given in smaller doses and in cycles, or intervals, to allow the normal cells to recover. This approach may not eradicate all of the tumor cells, and those that survive can evolve to become resistant to subsequent rounds of anti-cancer therapy.
For the study the team of researchers – which also involved investigators at the University of Washington, Oregon Health and Science University, the Buck Institute for Research on Aging, the Lawrence Berkeley National Laboratory – examined cancer cells from prostate, breast and ovarian cancer patients who had been treated with chemotherapy.
Una scoperta shoccante che ha messo in allerta la comunità medica internazionale. Secondo quanto pubblicato la chemioterapia provoca, nelle cellule sane circostanti il tumore, la secrezione di una particolare proteina che stimola la crescita del tumore e lo rende immune ai trattamenti.
La ricerca è stata effettuata su delle cellule raccolte da pazienti con tumore alla prostata e gli scienziati hanno scoperto che la chemioterapia danneggia il DNA delle cellule sane portandole a produrre elevate dosi della proteina WNT16B, che protegge il tumore e lo aiuta a svilupparsi.
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