Open AccessCalreticulin is a Critical Cell Survival Factor in Malignant Neoplasms
Author(s) -
Arum Han,
Chen Li,
Tara Zahed,
Michael K. Wong,
Ian F. Smith,
Karl Hoedel,
Douglas Green,
Alexander D. Boiko
Publication year - 2019
Publication title -
plos biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.127
H-Index - 271
eISSN - 1545-7885
pISSN - 1544-9173
DOI - 10.1371/journal.pbio.3000402
Subject(s) - calreticulin , biology , programmed cell death , cancer research , mitochondrial permeability transition pore , immunogenic cell death , gene knockdown , poly adp ribose polymerase , mitochondrion , microbiology and biotechnology , cell , apoptosis , polymerase , endoplasmic reticulum , genetics , gene
Calreticulin (CRT) is a high-capacity Ca 2+ protein whose expression is up-regulated during cellular transformation and is associated with disease progression in multiple types of malignancies. At the same time, CRT has been characterized as an important stress-response protein capable of inducing immunogenic cell death (ICD) when translocated to the cell surface. It remains unclear why CRT expression is preserved by malignant cells during the course of transformation despite its immunogenic properties. In this study, we identify a novel, critical function of CRT as a cell survival factor in multiple types of human solid-tissue malignancies. CRT knockdown activates p53, which mediates cell-death response independent of executioner caspase activity and accompanied full-length poly ADP ribose polymerase (PARP) cleavage. Mechanistically, we show that down-regulation of CRT results in mitochondrial Ca 2+ overload and induction of mitochondria permeability transition pore (mPTP)-dependent cell death, which can be significantly rescued by the mPTP inhibitor, Cyclosporin A (CsA). The clinical importance of CRT expression was revealed in the analysis of the large cohort of cancer patients ( N = 2,058) to demonstrate that high levels of CRT inversely correlates with patient survival. Our study identifies intracellular CRT as an important therapeutic target for tumors whose survival relies on its expression.