Cyclophosphamide and epirubicin induce high apoptosis in microglia cells while epirubicin provokes DNA damage and microglial activation at sub-lethal concentrations

Abstract

Chemotherapy Related Cognitive Impairment (CRCI), also called chemobrain, diminishes cancer patient's life quality. Breast cancer (BC) patients have been described to be importantly affected, however, the mechanism leading to CRCI has not been fully elucidated. Recent research proposes microglia as the main architect of CRCI, thus dysregulations in these cells could trigger CRCI. The aim of this research was to evaluate the effects of two drugs commonly used against breast cancer, cyclophosphamide (CTX) and epirubicin (EPI), on the microglia cell line SIM-A9, using the BC cell line, 4T1, as a control. Our results show that CTX and EPI decrease microglia-cell viability and increase cell death on a concentration-dependent manner, being 5 and 2 times more cytotoxic to microglia cell line than to breast cancer 4T1cells, respectively. Both chemotherapies induce cell cycle arrest and a significant increase in p53, p16 and γ-H2AX in breast cancer and microglia cells. Furthermore, mitochondrial membrane potential (ΔΨm) diminishes as cell death increases, and both chemotherapies induce reactive oxygen species (ROS) production on SIM-A9 and 4T1. Moreover, caspase activation increases with treatments and its pharmacological blockade inhibits CTX and EPI induced-cell death. Finally, low concentrations of CTX and EPI induce γ-H2AX, and EPI induces cytokine release, NO production and Iba-1 overexpression. These findings indicate that microglia cells are more sensitive to CTX and EPI than BC cells and undergo DNA damage and cell cycle arrest at very low concentrations, moreover EPI induces microglia activation and a pro-inflammatory profile.

Cerebral glucose changes after chemotherapy and their relation to long-term cognitive complaints and fatigue

“…Although both E and C are unable to cross the BBB at high concentrations ( 7 ), they can increase BBB permeability, enabling direct interactions ( 49 ). Moreover, at sublethal doses to cancer cells, E induces microglial activation ( 50 ), suggesting that treatment with EC is sufficient to induce an inflammatory reaction [observed here and earlier in the parietal/occipital cortex ( 8 )]. The addition of fluorouracil to the chemo-cocktail induced additional brain responses, as reflected by temporal and insular, but not occipital, relative hypermetabolism, suggesting that inflammatory (E) and oxidative stress (E + C) responses alone are insufficient to change metabolism in these regions, but rather require changes in cell proliferation (F + C) ( 48 ).…”

The bovine dialyzable leukocyte extract, immunepotent CRP, synergically enhances cyclophosphamide-induced breast cancer cell death, through a caspase-independent mechanism

“…Additionally, to test the effect of the combination therapy on immune system cells, with human peripheral blood mononuclear cells, we demonstrated that ICRP does not augment the cytotoxicity induced by CTX, which is desirable for a combination of treatments in which one of those, is known to have high cytotoxic effects in immune system cells, such as the induced by CTX and epirrubicin (EPI), another chemotherapy for the treatment of breast cancer, reported by de la Hoz-Camacho et al (2022[ 7 ]). Using HEK 293 (human embrionic kidney cells) and MDCK cells (Medin-Darby canine kidney), Singh et al, showed modest cytotoxicity induced by the combination of CTX with RES ranging from 5-15 % inhibition of cell viability.…”

“…Cyclophosphamide is a mainstay chemotherapy for breast cancer; its mechanism of cell death has been explored in several studies, which has been associated with ROS production and caspase-dependent cell death (Emadi and Brodsky et al,2009[ 8 ]; de la Hoz-Camacho et al, 2022[ 7 ]). On the other hand, Immunepotent CRP is a promising immunotherapy which modulates immune cells and induces non-apoptotic regulated cell death (caspase-independent) triggered by ROS production and involving mitochondrial and nuclear alterations in cells from cervical, lung and breast cancer cells, suggesting a conserved mechanism of cell death in solid tumors (Lorenzo-Anota et al, 2022[ 18 ]; Martínez-Torres et al, 2018[ 21 ] and 2019[ 20 ]; Reyes-Ruiz et al, 2021[ 30 ]); however, the cytotoxic effect of ICRP in combination with chemotherapies, including CTX, against breast cancer cells was reported here for the first time.…”

A Redox-Triggered Autophagy-Induced Nanoplatform with PD-L1 Inhibition for Enhancing Combined Chemo-Immunotherapy

“…Epirubicin (EPI) acts as a broad-spectrum antitumor drug with an antitumor mechanism that directly interferes with the transcription process, inhibiting the synthesis of DNA and RNA. 16 Meanwhile, STF-62247…”