IMMUNEPOTENT CRP increases intracellular calcium through ER-calcium channels, leading to ROS production and cell death in breast cancer and leukemic cell lines.

IMMUNEPOTENT CRP (ICRP) is an immunotherapy that induces cell death in cancer cell lines. However, the molecular mechanisms of death are not completely elucidated. Here, we evaluated the implication of intracellular Ca2+ augmentation in the cell death induced by ICRP on T-ALL and breast cancer cell lines. Cell death induction and the molecular characteristics of cell death were evaluated in T-ALL and breast cancer cell lines by assessing autophagosome formation, ROS production, loss of mitochondrial membrane potential, ER stress and intracellular Ca2+ levels. We assessed the involvement of extracellular Ca2+, and the implication of the ER-receptors, IP3R and RyR, in the cell death induced by ICRP, by using an extracellular calcium chelator and pharmacological inhibitors. Our results show that ICRP increases intracellular Ca2+ levels as the first step of the cell death mechanism that provokes ROS production and loss of mitochondrial membrane potential. In addition, blocking the IP3 and ryanodine receptors inhibited ER-Ca2+ release, ROS production and ICRP-induced cell death. Taken together our results demonstrate that ICRP triggers intracellular Ca2+-increase leading to different regulated cell death modalities in T-ALL and breast cancer cell lines. See also Figure 1(Fig. 1).

Changes in the natural killer cell repertoire and function induced by the cancer immune adjuvant candidate IMMUNEPOTENT-CRP.

Natural killer (NK) cells are CD3-, CD16+, CD56+ that play a crucial role in immune response by recognizing and eliminating a variety of virus-infected, malignant, and antibody-coated target cells. We examined activation; repertoire changes and effector functions of human NK cells normal donors treated with IMMUNEPOTENT-CRP (I-CRP), a bovine dialyzable leukocyte extract (DLE) containing a mixture of low molecular weight molecules. I-CRP induces human NK cells activation and increase CD56Dim CD16- subset, without inducing proliferation. Human NK cells showed an increase on NKp30, NKp44, NKp46, NKG2D, NKG2C and KIR receptors, whereas no significant differences on CD160, CD85j and CD226 where observed. I-CRP-treated human NK cells exhibited an increased degranulation activity against K562 target cells, as shown by CD107a assay, and this correlates with cytotoxicity against K562 cells observed in calcein release assay. These results indicate that I-CRP can modify human NK cells receptor repertoire leading to an increased cytotoxic activity, supporting evidence for its use to stimulate NK cells.