Antitumor Effect of Fluoxetine on Chronic Stress-Promoted Lung Cancer Growth via Suppressing Kynurenine Pathway and Enhancing Cellular Immunity

Chronic Stress Exacerbates the Immunosuppressive Microenvironment and Progression of Gliomas by Reducing Secretion of CCL3

As understanding of cancer has deepened, increasing attention has been turned to the roles of psychological factors, especially chronic stress-induced depression, in the occurrence and development of tumors. However, whether and how depression affects the progression of gliomas are still unclear. In this study, we have revealed that chronic stress inhibited the recruitment of tumor-associated macrophages (TAM) and other immune cells, especially M1-type TAMs and CD8+ T cells, and decreased the level of proinflammatory cytokines in gliomas, leading to an immunosuppressive microenvironment and glioma progression. Mechanistically, by promoting the secretion of stress hormones, chronic stress inhibited the secretion of the chemokine CCL3 and the recruitment of M1-type TAMs in gliomas. Intratumoral administration of CCL3 reprogrammed the immune microenvironment of gliomas and abolished the progression of gliomas induced by chronic stress. Moreover, levels of CCL3 and M1-type TAMs were decreased in the tumor tissues of glioma patients with depression, and CCL3 administration enhanced the antitumor effect of anti-PD-1 therapy in orthotopic models of gliomas undergoing chronic stress. In conclusion, our study has revealed that chronic stress exacerbates the immunosuppressive microenvironment and progression of gliomas by reducing the secretion of CCL3. CCL3 alone or in combination with an anti-PD-1 may be an effective immunotherapy for the treatment of gliomas with depression. See related Spotlight by Cui and Kang, p. 514.

The beneficial effect of fluoxetine on behavioral and cognitive changes in chronic experimental Chagas disease unveils the role of serotonin fueling astrocyte infection by Trypanosoma cruzi

BACKGROUND

In Chagas disease (CD), a neglected tropical disease caused by the parasite Trypanosoma cruzi, the development of mental disorders such as anxiety, depression, and memory loss may be underpinned by social, psychological, and biological stressors. Here, we investigated biological factors underlying behavioral changes in a preclinical model of CD.

METHODOLOGY/PRINCIPAL FINDINGS

In T. cruzi-infected C57BL/6 mice, a kinetic study (5 to 150 days postinfection, dpi) using standardized methods revealed a sequential onset of behavioral changes: reduced innate compulsive behavior, followed by anxiety and depressive-like behavior, ending with progressive memory impairments. Hence, T. cruzi-infected mice were treated (120 to 150 dpi) with 10 mg/Kg/day of the selective serotonin reuptake inhibitor fluoxetine (Fx), an antidepressant that favors neuroplasticity. Fx therapy reversed the innate compulsive behavior loss, anxiety, and depressive-like behavior while preventing or reversing memory deficits. Biochemical, histological, and parasitological analyses of the brain tissue showed increased levels of the neurotransmitters GABA/glutamate and lipid peroxidation products and decreased expression of brain-derived neurotrophic factor in the absence of neuroinflammation at 150 dpi. Fx therapy ameliorated the neurochemical changes and reduced parasite load in the brain tissue. Next, using the human U-87 MG astroglioma cell line, we found no direct effect of Fx on parasite load. Crucially, serotonin/5-HT (Ser/5-HT) promoted parasite uptake, an effect increased by prior stimulation with IFNγ and TNF but abrogated by Fx. Also, Fx blocked the cytokine-driven Ser/5-HT-promoted increase of nitric oxide and glutamate levels in infected cells.

CONCLUSION/SIGNIFICANCE

We bring the first evidence of a sequential onset of behavioral changes in T. cruzi-infected mice. Fx therapy improves behavioral and biological changes and parasite control in the brain tissue. Moreover, in the central nervous system, cytokine-driven Ser/5-HT consumption may favor parasite persistence, disrupting neurotransmitter balance and promoting a neurotoxic environment likely contributing to behavioral and cognitive disorders.

Ansofaxine hydrochloride inhibits tumor growth and enhances Anti-TNFR2 in murine colon cancer model

Introduction: As psychoneuroimmunology flourishes, there is compelling evidence that depression suppresses the anti-tumor immune response, promotes the progression of cancer, and inhibits the effectiveness of cancer immunotherapy. Recent studies have reported that antidepressants can not only alleviate the depressant condition of cancer patients, but also strengthen the anti-tumor immunity, thus suppressing tumors. Tumor necrosis factor receptor 2 (TNFR2) antagonistic antibodies (Anti-TNFR2) targeting tumor-infiltrating regulatory T cells (Tregs) has achieved great results in preclinical studies, and with a favorable toxicity profile than existing immunotherapies, and is expected to become a new generation of more effective treatment strategies. Understanding the effects of combination therapy with antidepressants and Anti-TNFR2 may help design new strategies for cancer immunotherapy. Methods: We treated CT26, HCT116, MCA38 and SW620 colon cancer cells with fluoxetine (0-50 µM), ansofaxine hydrochloride (0-50 µM) and amitifadine hydrochloride (0-150 µM) to examine their effects on cell proliferation and apoptosis. We explored the antitumor effects of ansofaxine hydrochloride in combination with or without Anti-TNFR in subcutaneously transplanted CT26 cells in tumor-bearing mouse model. Antitumor effects were evaluated by tumor volume. NK cell, M1 macrophage cell, CD4+ T cell, CD8+ T cell, exhausted CD8+ T and regulatory T cell (Tregs) subtypes were measured by flow cytometry. 5-hydroxytryptamine, dopamine and norepinephrine levels were measured by ELISA. Results: Oral antidepression, ansofaxine hydrochloride, enhanced peripheral dopamine levels, promoted CD8+T cell proliferation, promoted intratumoral infiltration of M1 and NK cells, decreased the proportion of tumor-infiltrating exhausted CD8+T cells, and strengthened anti-tumor immunity, thereby inhibiting colon cancer growth. In combination therapy, oral administration of ansofaxine hydrochloride enhanced the efficacy of Anti-TNFR2, and produced long-term tumor control in with syngeneic colorectal tumor-bearing mice, which was attributable to the reduction in tumor-infiltrating Treg quantity and the recovery of CD8+ T cells function. Discussion: In summary, our data reveal the role of ansofaxine hydrochloride in modulating the anti-tumor immunity. Our results support that exhausted CD8+T is an important potential mechanism by which ansofaxine hydrochloride activates anti-tumor immunity and enhances anti-tumor effects of anti-TNFR2.

Lactobacillus reuteri strain 8008 attenuated the aggravation of depressive-like behavior induced by CUMS in high-fat diet-fed mice through regulating the gut microbiota

Objective: Gut microbiota play a key role in the pathogenesis of obesity and depression. Probiotics are a preventive strategy for obesity and a novel treatment for depression symptoms. However, the ameliorative or therapeutic effect of potential probiotic candidate Lactobacillus reuteri (L. reuteri) on obesity and depression comorbidity still remains unclear. We investigated the effects of chronic unpredictable mild stress (CUMS) in high-fat diet-fed mice and the effects of Lactobacillus reuteri strain 8008 on various disease indicators of obesity and depression comorbidity disease. Methods: Forty male C57BL/6 mice were randomized into 2 groups: the normal control (NC) group (n = 10) and the high-fat diet (HFD) group (n = 30), being fed with normal diet (ND) or high-fat diet (HFD) for 8 weeks, respectively. Then the obese mice fed with HFD were randomly allocated into 3 sub-groups: the HFD group (n = 10); the HFD + CUMS group (n = 10); the HFD + CUMS + L.r group (n = 10). The latter 2 subgroups underwent CUMS for 4 weeks to build the obesity and depression comorbidity mice model. During the duration of treatment, mice were gavaged with 0.5 mL PBS solution or L. reuteri (2 × 109 CFU/mL) once a day, respectively. The body weight, food intake, organ weight, behavioral indicators, histology, blood lipids, levels of inflammatory cytokines and tight junction proteins and abundance of colonic contents bacteria were measured. Results: The obesity and depression comorbidity mice model was successfully established after HFD feeding and chronic stress. The comorbid mice demonstrated inflammatory responses increase in liver and adipose tissues, worsened damage to the intestinal barrier as well as gut microbiota disorder. Gavaged with L. reuteri attenuated depressive-like behavior, improved blood lipids and insulin resistance, reduced inflammation in liver and adipose tissues, improved intestinal tight junctions as well as the microbiome dysbiosis in obesity and depression comorbidity mice. Conclusion: Lactobacillus reuteri strain 8008 could alleviate depressive-like behaviors and related indicators of obesity disorders by regulating the gut microbiota in obesity and depression comorbid mice.

Could peripheral 5-HT level be used as a biomarker for depression diagnosis and treatment? A narrative minireview

The serotonin hypothesis of depression is still influential, but the relationship between peripheral 5-HT levels and depression is still unknown. This review aimed to verify whether peripheral 5-HT levels could be used as a biomarker for depression diagnosis and treatment. PubMed and EMBASE were searched using terms appropriate to the area of research. Articles from 1957 to 2022 in the following terms were identified: depression, 5-HT, serotonin and peripheral (serum, plasma, blood platelets). 33 studies were included: seven clinical trials about periphery 5-HT levels in depressive patients compared to normal subjects, 15 clinical trials about changes of peripheral 5-HT levels in patients with depression after drug treatment and 11 animal experiments about peripheral 5-HT levels in animal models of depression. Peripheral 5-HT levels presented three different outcomes before and after antidepressant treatments: increased, decreased and no significant change. In conclusion, changes in peripheral 5-HT levels did not show consistent results among these studies. Peripheral 5-HT level could not be used as a biomarker both for depression diagnosis and for antidepressant efficacy evaluation.

Jujuboside B Reverse CUMS-Promoted Tumor Progression via Blocking PI3K/Akt and MAPK/ERK and Dephosphorylating CREB Signaling

Background

Jujuboside B (JUB) is a saponins isolated from the seeds of Zizyphi jujuba var. spinosi, which is used to treat mental illness and is reported recently to induce cancer cell apoptosis. As our previous research showed chronic stress promoted tumor growth, this work aims to investigate whether JUB exert antitumor effect in addition to its antidepressant effect and possible mechanism.

Methods

56 female C57BL/6 mice were grouped into 7 groups: A (blank control), B (tumor-bearing control), C (tumor-bearing + JUB), D (CUMS control), E (CUMS + JUB), F (tumor-bearing + CUMS), and G (tumor-bearing + CUMS + JUB). Groups C, E, G, B, D, and F were administered, respectively, with JUB (40 mg/kg/day) or vehicle for 2 weeks. Serum 5-HT, Trp (tryptophane), inflammatory cytokines TNF-α, IL-4, -6, and -10 levels were detected by ELISA. The tumors in groups B and F were isolated for RNA-seq sequencing. Protein and mRNA expression of Bax, Bcl-2, p-PI3K, p-Akt, p-MAPK, p-ERK, and p-CREB in tumor tissues were detected. In vitro, A549 cells were stimulated with JUB (60 μmol/L), in which proliferation rate and colony formation rate were detected. The PI3K/Akt and, MAPK/ERK pathway were measured.

Results

Chronic stress successfully induced the depression-like phenotype (group D vs. A) and promoted tumor growth (group B vs. F). JUB significantly ameliorated the depression-like phenotype and increased 5-HT, Trp levels (group D vs. E), and reversing CUMS-induced tumor progression. Meanwhile, JUB decreased inflammatory cytokine levels. Chronic stress upregulated the phosphorylation levels of PI3K/Akt/MAPK/ERK/CREB; JUB reversed this regulation. JUB significantly inhibited cell viability, colony formation rate, and downregulated the phosphorylation levels of PI3K/Akt/MAPK/ERK/CREB in vitro.

Conclusions

JUB reverses CUMS-promoted tumor progression in tumor-bearing mice with depression-like phenotype. JUB exerts the dual beneficial effect on tumor growth and depression-like phenotype by blocking the signal transduction pathway of PI3K/Akt, MAPK/ERK, and dephosphorylating the downstream signaling regulator CREB.

Sex differences in peripheral monoamine transmitter and related hormone levels in chronic stress mice with a depression-like phenotype

Backgrounds

Chronic stress could induce depression-like phenotype in animal models. Previous data showed that sex differences exist after chronic stress model establishment, however, the detailed information about the difference of blood biochemical indexes is not clear. In this study, we aim to supply comparison of monoamine transmitters and related hormone markers in serum between male and female depressed mice, and in order to better understand the sex difference in transmitters and hormone levels in depression occurrence and development.

Methods

Sixty C57BL/6 mice (both male and female) were divided into two groups by gender. Same gender mice were then divided randomly into the non-treated control group and chronic stress group which was exposed to 8 weeks of chronic unpredictable mild stress (CUMS). Depression-like behavior was assessed with open-field test and sucrose preference test. Blood sample was collected and monoamine transmitter and related hormone in serum were measured by ELISA.

Results

The depression-like phenotype mice model was established successfully after 8 weeks of chronic stress. The locomotion activity scores in male stressed mice declined more than that in female stressed mice, while the exploratory behavior scores in female stressed mice declined more than that in male stressed mice. Compared to non-treated control group mice, mice in the chronic stress group in response to stress showed greater declines in monoamine transmitters (5-HT, dopamine, norepinephrine) and sex hormones (androgen, estrogen, oxytocin and prolactin), while stress hormones (adrenaline, corticosterone and ACTH) were significantly increased. The decrease of norepinephrine, androgen and estrogen in female stressed mice was greater than in male stressed mice, whereas the 5-HT and oxytocin in male stressed mice decreased more than in female stressed mice, and the corticosterone in male stressed mice increased more than in female stressed mice.

Conclusion

Sex differences of monoamine transmitter and related hormone levels in serum occurred in chronic stress induced depression-like phenotype mice model. It may provide a useful reference to guide precise antidepressant treatment in different gender population in clinical care.

Lung adenocarcinoma-related target gene prediction and drug repositioning

Lung cancer is the leading cause of cancer deaths globally, and lung adenocarcinoma (LUAD) is the most common type of lung cancer. Gene dysregulation plays an essential role in the development of LUAD. Drug repositioning based on associations between drug target genes and LUAD target genes are useful to discover potential new drugs for the treatment of LUAD, while also reducing the monetary and time costs of new drug discovery and development. Here, we developed a pipeline based on machine learning to predict potential LUAD-related target genes through established graph attention networks (GATs). We then predicted potential drugs for the treatment of LUAD through gene coincidence-based and gene network distance-based methods. Using data from 535 LUAD tissue samples and 59 precancerous tissue samples from The Cancer Genome Atlas, 48,597 genes were identified and used for the prediction model building of the GAT. The GAT model achieved good predictive performance, with an area under the receiver operating characteristic curve of 0.90. 1,597 potential LUAD-related genes were identified from the GAT model. These LUAD-related genes were then used for drug repositioning. The gene overlap and network distance with the target genes were calculated for 3,070 drugs and 672 preclinical compounds approved by the US Food and Drug Administration. At which, bromoethylamine was predicted as a novel potential preclinical compound for the treatment of LUAD, and cimetidine and benzbromarone were predicted as potential therapeutic drugs for LUAD. The pipeline established in this study presents new approach for developing targeted therapies for LUAD.

Crosstalk between ILC2s and Th2 CD4+ T Cells in Lung Disease

Cytokine secretion, such as interleukin-4 (IL-4), IL-5, IL-9, IL-13, and amphiregulin (Areg), by type 2 innate lymphoid cells (ILC2s) is indispensable for homeostasis, remodeling/repairing tissue structure, inflammation, and tumor immunity. Often viewed as the innate cell surrogate of T helper type 2 (Th2) cells, ILC2s not only secrete the same type 2 cytokines, but are also inextricably related to CD4⁺T cells in terms of cell origin and regulatory factors, bridging between innate and adaptive immunity. ILC2s interact with CD4⁺T cells to play a leading role in a variety of diseases through secretory factors. Here, we review the latest progress on ILC2s and CD4⁺T cells in the lung, the close relationship between the two, and their relevance in the lung disease and immunity. This literature review aids future research in pulmonary type 2 immune diseases and guides innovative treatment approaches for these diseases.