“…However, activation of these stress sensitive protein kinases did not appear to be involved in combination-induced cell death in HCC cells, but rather, as reported by others, their activation seem to be associated with a protective response against the drug treatment. 33 At the molecular level, proteasome inhibitors and celecoxib exert antitumor activity via different mechanisms, however both are known to trigger endoplasmic reticulum stress response (ESR), which kills cancer cells. [9][10][11][12][18][19][20] The important role of ESR in tumor cell growth and survival has been recently recognized.…”