Bystander effects are induced by CENU treatment and associated with altered protein secretory activity of treated tumor cells A relay for chemotherapy?

Abstract

In a previous study, it was reported that secondary untreated melanoma tumors implanted several weeks after and at distance from primary chloroethylnitrosourea (CENU)-treated tumors underwent differentiation and growth inhibition. To see whether the primary treated tumor released soluble factors that mediated the secondary tumor response, serum transfer experiments were performed in vivo. Administration of serum from CENU-treated tumor-bearing donors arrested tumor proliferation, decreased vessel formation and induced tumor metabolite alterations encompassing glutathione decrease and polyunsaturated fatty acid and phosphoethanolamine increase. These changes mimicked secondary tumor phenotype. To reproduce the model in vitro, cell culture supernatant transfer experiments were performed. CENU-treated cell cultures showed polyploidy and reactive oxygen species (ROS) production. Cell cultures challenged by a conditioned medium of CENU-treated cells underwent growth inhibition, cytoskeleton disorders, cytokinesis retardation, metabolite alterations, glutathione decrease and phosphoethanolamine increase, without ROS elicitation. Proteomics of CENU-treated cell conditioned media revealed altered protein secretion activity by CENU-treated cells. Among de novo secreted proteins, the most expressed were phosphatidylethanolamine-binding protein (PEBP), cardiovascular heat shock protein (cHsp), Rho-associated coiled-coil forming kinase 2 (ROCK) and actin fragments. These proteins testified of cytoskeleton disorders, growth inhibition and metabolite alterations. This article demonstrates the release by CENU-treated tumors of growth inhibitory differentiation-inducing soluble factors. These factors mediate remote bystander effects and attest persistent biological activity of residual tumors after chemotherapy. ' 2006 Wiley-Liss, Inc.Key words: chloroethylnitrosoureas; distant double tumor models; growth inhibition; bystander effects; proteomics There is increasing experimental evidence that therapy-induced tumor cell modification (cell-based gene and ionizing radiation therapies) may promote the immune system or induce the expression of cytokines or other factors that may be inhibitory for local or distant unmodified tumor cells. [1][2][3][4][5][6][7][8] Cell-based gene therapy after cytokine or suicide gene transfer has been investigated for autologous and allogeneic vaccination in cancer therapy. Tumor cells engineered to produce cytokines such as interleukin-12 (IL-12) induced antitumor immunity capable of inhibiting a challenge with unmodified parental tumor cells.1 Recently, in a model of allogeneic tumor cells transduced with IL-12 mixed with autologous lymphoma cells, IL-12 induced microenvironmental changes that, through the induction of an immune response, yielded eradication of distant preestablished lymphoma.2 Cells transfected with a suicide gene such as that of thymidine kinase from herpes simplex virus 3-6 or of cytosine desaminase, 7-8 enzymes that activate a drug or prodrug, inhibited distant tumors and provok...

CENU treatment induced bystander effects which are effective on parental and non-parental tumors and have a phospholipid metabolism proton NMR spectroscopy signature

“…This was consistent with alterations in membrane metabolism with a decrease of membrane degradation products (17-19), a decrease of cytosolic phospholipase A 2 expression (20), the inhibition of excessive Plp biosynthesis or increased Plp consumption (16). Such persistent phospholipid metabolism alteration was also observed in CENU-treated primary B16 and untreated secondary B16 melanoma tumors, mainly consisting of an increase in PE (4,11). PE was a metabolic marker found in other types of tumor cells when they escaped therapy-induced cell death, and could be a mediator of cell survival in tumors (11,21).…”

“…These phenotypes changes were similar to those of treated tumors (3). These findings allowed us to demonstrate that primary CENU-treated tumors released a factor having inhibitory properties on distant secondary untreated tumors (4). We named this phenomenon the chemotherapy-induced bystander effect, in analogy with the similar phenomenon in ionizing radiation studies (4)(5)(6).…”

“…We named this phenomenon the chemotherapy-induced bystander effect, in analogy with the similar phenomenon in ionizing radiation studies (4)(5)(6). Some proteins were released by CENUtreated B16 melanoma cells, such as phosphatidylethanolaminebinding protein, cardiovascular heat-shock protein, Rhoassociated coiled-coil forming kinase 2 and actin fragments, which accompanied the expression of the bystander factors (4).…”

Pharmacometabolomics of docetaxel-treated human MCF7 breast cancer cells provides evidence of varying cellular responses at high and low doses

“…Moreover, GSx depletion is associated with lipid peroxidation and oxidative DNA damage [49]. It was found to be associated with lipid accumulation in human erythroleukemia K562 cells exposed to paclitaxel [28,32] and to PE accumulation in B16 melanoma cells exposed to oxidative stress [50]. Conversely, GSx depletion may activate PKCa [51], as a survival process.…”

Fasudil inhibits lung carcinoma-conditioned endothelial cell viability and migration

“…Rho-kinase regulates stress fibre formation and cell-cell junctions in ECs in response to vascular endothelial derived growth factor (VEGF) (6). Members of the Rho family of GTPases have also emerged as key players in the regulation of a variety of biological activities involving cell motility and actin cytoskeleton reorganization (7).…”