Cytokine-associated fatigue prior to, during, and post-chemotherapy for breast cancer

The GDF15-GFRAL axis mediates chemotherapy-induced fatigue in mice

Cancer-related fatigue is defined as a distressing persistent subjective sense of physical, emotional, and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and that interferes with usual functioning. This form of fatigue is highly prevalent during cancer treatment and in some patients, it can persist for years after treatment has ended. An understanding of the mechanisms that drive cancer-related fatigue is still lacking, which hampers the identification of effective treatment options. Various chemotherapeutic agents including cisplatin are known to induce mitochondrial dysfunction and this effect is known to mediate chemotherapy-induced peripheral neuropathy and cognitive dysfunction. Mitochondrial dysfunction results in the release of mitokines that act locally and at distance to promote metabolic and behavioral adjustments to this form of cellular stress. One of these mitokines, growth differentiation factor 15 (GDF15) and its receptor, glial cell line-derived neurotrophic factor family receptor α-like (GFRAL), have received special attention in oncology as activation of GFRAL mediates the anorexic response that is responsible for cancer anorexia. The present study was initiated to determine whether GDF15 and GFRAL are involved in cisplatin-induced fatigue. We first tested the ability of cisplatin to increase circulating GDF15 in mice before assessing whether GDF15 can induce behavioral fatigue measured by decreased wheel running in healthy mice and increase behavioral fatigue induced by cisplatin. Mice administered a long acting form of GDF15, mGDF15-fc, decreased their voluntary wheel running activity. When the same treatment was administered to mice receiving cisplatin, it increased the amplitude and duration of cisplatin-induced decrease in wheel running. To determine whether endogenous GDF15 mediates the behavioral fatigue induced by cisplatin, we then administered a neutralizing monoclonal antibody to GFRAL to mice injected with cisplatin. The GFRAL neutralizing antibody mostly prevented cisplatin-induced decrease in wheel running and accelerated recovery. Taken together these findings demonstrate for the first time the role of the GDF15/GFRAL axis in cisplatin-induced behaviors and indicate that this axis could be a promising therapeutic target for the treatment of cancer-related fatigue.

Kai-Xin-San Attenuates Doxorubicin-Induced Cognitive Impairment by Reducing Inflammation, Oxidative Stress, and Neural Degeneration in 4T1 Breast Cancer Mice

Objective

This study explored the potential therapeutic effect and possible mechanism of Kai-Xin-San (KXS) on doxorubicin-induced cognitive impairment in 4T1 breast cancer mice.

Methods

A model of chemotherapy-induced cognitive impairment (CICI) was established with the injection of doxorubicin (DOX, 5 mg/kg) at a 7-day interval in a 4T1 breast cancer mouse. KXS was given (1 g/kg) daily by gavage over three weeks starting at the first week while giving DOX. The Morris water maze task was performed to measure the CICI-like behaviors. Oxidative stress markers in the hippocampus, inflammatory cytokines in the serum and hippocampus, Nissl staining, immunofluorescence staining, and analysis for Glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 of the hippocampus were examined to explore the effect and mechanism of KXS on DOX-induced CICI. Meanwhile, tumor growth and survival time were tested in this study.

Results

CICI-like behaviors induced by DOX occurred earlier and were severer than the cognitive impairment induced by the tumor, and the effect of KXS on improving the cognitive impairment was obvious. KXS protected against DOX-induced neuroinflammation by decreasing levels of proinflammatory cytokines interleukin-6, interleukin-12p70, and tumor necrosis factor-alpha in both serum and brain and interleukin-1β in the brain, increasing the anti-inflammatory cytokines interleukin-4 in the serum and interleukin-10 in the hippocampus, and inhibiting the astrocytic hyperplasia and microglial polarization in the hippocampus. KXS reduced neural degeneration and protected against DOX-induced oxidative stress according to decreased malondialdehyde level, increased glutathione level, and enhanced activities of superoxide dismutase, catalase, and glutathione peroxidase. Moreover, KXS recovered the lost body weights after DOX administration and prolonged the survival times of mice.

Conclusions

KXS may attenuate DOX-induced cognitive impairment by regulating inflammatory responses and reducing oxidative stress and neural degeneration. These findings also presented the role of KXS in improving the quality of life and prolonging survival time in breast cancer mice that received chemotherapy.

Distinct cytokine profiles across trajectories of self-perceived cognitive impairment among early-stage breast cancer survivors

The aim of the current study is to identify distinct cytokine profiles in relation to self-perceived cognitive trajectories. In our study cohort (n = 128), early-stage breast cancer patients were categorized into no impairment reported, acute, delayed, persistent and intermittent cognitive decline respectively. Pro-inflammatory cytokines were elevated compared to baseline; with TNF-α implicated in the acute cognitive trajectory while IL-6 and IL-8 were involved in the persistent cognitive trajectory. Our findings help to further our understanding of cytokine profiles implicated in cancer-related cognitive impairment (CRCI) and support the use of cytokine levels as biomarkers of cognitive decline over time.