Effect of antidepressants on body weight, ethology and tumor growth of human pancreatic carcinoma xenografts in nude mice

Beyond Psychotropic: Potential Repurposing of Fluoxetine toward Cancer Therapy

Drug repurposing, rebranding an existing drug for a new therapeutic indication, is deemed a beneficial approach for a quick and cost-effective drug discovery process by skipping preclinical, Phase 1 trials and pharmacokinetic studies. Several psychotropic drugs, including selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs), were studied for their potential application in different diseases, especially in cancer therapy. Fluoxetine (FLX) is one of the most prescribed psychotropic agents from the SSRIs class for the treatment of several neuropsychiatric disorders with a favorable safety profile. FLX exhibited different oncolytic effects via mechanisms distinct from its main serotonergic activity. Taking advantage of its ability to rapidly penetrate the blood-brain barrier, FLX could be particularly useful in brain tumors. This was proved by different in vitro and in vivo experiments using FLX as a monotherapy or combination with temozolomide (TMZ) or radiotherapy. In this review of the literature, we summarize the potential pleiotropic oncolytic roles of FLX against different cancers, highlighting the multifaceted activities of FLX and its ability to interrupt cancer proliferation via several molecular mechanisms and even surmount multidrug resistance (MDR). We elaborated on the successful synergistic combinations such as FXR/temozolomide and FXR/raloxifene for the treatment of glioblastoma and breast cancer, respectively. We showcased beneficial pharmaceutical trials to load FLX onto carriers to enhance its safety and efficacy on cancer cells. This is the first review article extensively summarizing all previous FLX repurposing studies for the management of cancer.

Nicotinamide Adenine Dinucleotide Precursor Suppresses Hepatocellular Cancer Progression in Mice

Targeting Nicotinamide adenine dinucleotide (NAD) metabolism has emerged as a promising anti-cancer strategy; we aimed to explore the health benefits of boosting NAD levels with nicotinamide riboside (NR) on hepatocellular carcinoma (HCC). We established three in vivo tumor models, including subcutaneous transplantation tumor model in both Balb/c nude mice (xenograft), C57BL/6J mice (allograft), and hematogenous metastatic neoplasm in nude mice. NR (400 mg/kg bw) was supplied daily in gavage. In-situ tumor growth or noninvasive bioluminescence were measured to evaluate the effect of NR on the HCC process. HepG2 cells were treated with transforming growth factor-β (TGF-β) in the absence/presence of NR in vitro. We found that NR supplementation alleviated malignancy-induced weight loss and metastasis to lung in nude mice in both subcutaneous xenograft and hematogenous metastasis models. NR supplementation decreased metastasis to the bone and liver in the hematogenous metastasis model. NR supplementation also significantly decreased the size of allografted tumors and extended the survival time in C57BL/6J mice. In vitro experiments showed that NR intervention inhibited the migration and invasion of HepG2 cells triggered by TGF-β. In summary, our results supply evidence that boosting NAD levels by supplementing NR alleviates HCC progression and metastasis, which may serve as an effective treatment for the suppression of HCC progression.

IDO1 Is a Therapeutic Target for Pancreatic Cancer-Associated Depression

Metabolites of tryptophan degradation are known to alter mood. Their effects have only been superficially examined in the context of pancreatic cancer. Herein, we study the role of indoleamine 2,3-dioxygenase 1 (IDO1), an enzyme important in the conversion of tryptophan to kynurenine, in a murine model of pancreatic cancer-associated depression. Behavioral tests (open field, forced swim, tail suspension, and elevated plus maze) and biochemical assays (LC-MS metabolomics) were used to characterize a depressive-phenotype in tumor-bearing mice (relative to non-tumor-bearing mice). In addition, we determine whether pharmacologic blockade of IDO1 affects mood in tumor-bearing mice. Immunocompetent mice bearing orthotopic pancreatic tumors exhibit depressive-like behavior relative to non-tumor-bearing mice. Pancreatic tumors strongly express IDO1. Consequently, serum kynurenine levels in tumor-bearing mice are elevated relative to non-tumor-bearing mice. Tumor-bearing mice treated with epacadostat, an IDO1 inhibitor, exhibited improved mood relative to mice receiving vehicle. There was a 95% reduction in serum kynurenine levels in mice receiving epacadostat relative to mice treated with vehicle. As confirmatory evidence of on-target activity, tumors of mice treated with epacadostat exhibited a compensatory increase in IDO1 protein levels. Escitalopram, an approved antidepressant, was ineffective at improving mood in tumor-bearing mice as measured by behavioral assays and did not affect kynurenine levels. Neither epacadostat, nor escitalopram, affected overall survival relative to vehicle. Mice with pancreatic cancer exhibit depressive-like behavior. Epacadostat was effective as an antidepressant for pancreatic cancer-associated depression in mice. These data offer a rationale to consider IDO1 inhibition as a therapeutic strategy to mitigate depressive symptoms in patients with pancreatic cancer.

A comprehensive metabolomics investigation of hippocampus, serum, and feces affected by chronic fluoxetine treatment using the chronic unpredictable mild stress mouse model of depression

A metabolomic investigation of depression and chronic fluoxetine treatment was conducted using a chronic unpredictable mild stress model with C57BL/6N mice. Establishment of the depressive model was confirmed by body weight measurement and behavior tests including the forced swim test and the tail suspension test. Behavioral despair by depression was reversed by four week-treatment with fluoxetine. Hippocampus, serum, and feces samples collected from four groups (control + saline, control + fluoxetine, model + saline, and model + fluoxetine) were subjected to metabolomic profiling based on ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. Alterations in the metabolic patterns were evident in all sample types. The antidepressant effects of fluoxetine appeared to involve various metabolic pathways including energy metabolism, neurotransmitter synthesis, tryptophan metabolism, fatty acid metabolism, lipid metabolism, and bile acid metabolism. Predictive marker candidates of depression were identified, including β-citryl-L-glutamic acid (BCG) and docosahexaenoic acid (DHA) in serum and chenodeoxycholic acid and oleamide in feces. This study suggests that treatment effects of fluoxetine might be differentiated by altered levels of tyramine and BCG in serum, and that DHA is a potential serum marker for depression with positive association with hippocampal DHA. Collectively, our comprehensive study provides insights into the biochemical perturbations involved in depression and the antidepressant effects of fluoxetine.

Does use of tetracyclic antidepressant-mirtazapine reduce cancer risk in depression patients?

PURPOSE

We conducted a nested case-control study to evaluate the association between risk of cancer and mirtazapine use in depression patients in Taiwan.

METHODS

We obtained data from the Taiwan National Health Insurance Research Database to conduct a population-based nested case-control study. The study cohort included 16 897 patients diagnosed with depression between January 1, 2000 and December 31, 2008. We identified 530 cancer patients as the study group and matched 4 non-cancer subjects with each cancer patient by incident density, age, and sex. Odds ratios and 95% confidence intervals were estimated using multivariate conditional logistic regression analysis.

RESULTS

Use of mirtazapine for depression did not have significant effect on overall cancer incidence (odds ratio: 1.03, 95% confidence interval: 0.72-1.48). Further analysis of annual mirtazapine dosages and the duration of mirtazapine use revealed no significant effect on cancer risk.

CONCLUSION

The findings of this population-based nested case-control study suggest that mirtazapine use may not provide a tumor suppression effect in humans such as that seen in the animal model. Future large-scale and in-depth investigations in this area are warranted.

Antiproliferative effects of fluoxetine on colon cancer cells and in a colonic carcinogen mouse model

The antidepressant fluoxetine has been under discussion because of its potential influence on cancer risk. It was found to inhibit the development of carcinogen-induced preneoplastic lesions in colon tissue, but the mechanisms of action are not well understood. Therefore, we investigated anti-proliferative effects, and used HT29 colon tumor cells in vitro, as well as C57BL/6 mice exposed to intra-rectal treatment with the carcinogen N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) as models. Fluoxetine increased the percentage of HT29 cells in the G₀/G₁ phase of cell-cycle, and the expression of p27 protein. This was not related to an induction of apoptosis, reactive oxygen species or DNA damage. In vivo, fluoxetine reduced the development of MNNG-induced dysplasia and vascularization-related dysplasia in colon tissue, which was analyzed by histopathological techniques. An anti-proliferative potential of fluoxetine was observed in epithelial and stromal areas. It was accompanied by a reduction of VEGF expression and of the number of cells with angiogenic potential, such as CD133, CD34, and CD31-positive cell clusters. Taken together, our findings suggest that fluoxetine treatment targets steps of early colon carcinogenesis. This confirms its protective potential, explaining at least partially the lower colon cancer risk under antidepressant therapy.

Intervention of Mirtazapine on gemcitabine-induced mild cachexia in nude mice with pancreatic carcinoma xenografts

AIM: To investigate the effect of Mirtazapine on tumor growth, food intake, body weight, and nutritional status in gemcitabine-induced mild cachexia.

METHODS: Fourteen mice with subcutaneous xenografts of a pancreatic cancer cell line (SW1990) were randomly divided into Mirtazapine and control groups. Either Mirtazapine (10 mg/kg) or saline solution was orally fed to the mice every day after tumor implantation. A model of mild cachexia was then established in both groups by intraperitoneal injection of Gemcitabine (50 mg/kg) 10 d, 13 d, and 16 d after tumor implantation. Tumor size, food intake, body weight, and nutritional status were measured during the experiment. All mice were sacrificed at day 28.

RESULTS: (1) After 7 d of gemcitabine administration, body-weight losses of 5%-7% which suggested mild cachexia were measured; (2) No significant difference in tumor size was detected between the Mirtazapine and control groups (P > 0.05); and (3) During the entire experimental period, food intake and body weight were slightly greater for the Mirtazapine group compared with controls (although these differences were not statistically significant). After 21 d, mice in the Mirtazapine group consumed significantly more food than control mice (3.95 ± 0.14 g vs 3.54 ± 0.10 g, P = 0.004). After 25 d, mice in the Mirtazapine group were also significantly heavier than control mice (17.24 ± 0.53 g vs 18.05 ± 0.68 g, P = 0.014).

CONCLUSION: Mild cachexia model was successfully established by gemcitabine in pancreatic tumor-bearing mice. Mirtazapine can improve gemcitabine-induced mild cachexia in pancreatic tumor-bearing mice. It was believed to provide a potential therapeutic perspective for further studies on cachexia.

Early treatment with mirtazapine improves food intake and nutritional status in a gemcitabine-induced mild cachexia mouse model with pancreatic cancer

AIM: To investigate the effect of early treatment with mirtazapine on food intake and nutritional status in a gemcitabine-induced mild cachexia mouse model with pancreatic cancer.

METHODS: After a subcutaneous xenograft model of pancreatic cancer was established, 21 xenograft nude mice were randomly and equally divided into control group, early mirtazapine treatment group and late mirtazapine treatment group. The two treatment groups were given 10 mg/(kg•d) mirtazapine once daily by oral gavage from day 1 and day 10 after transplantation, respectively. All animals were given 50 mg/kg of gemcitabine i. p. on days 10, 13 and 16 after transplantation. All mice were sacrificed on day 28. Body weight, food intake, tumor size, subcutaneous fat, arm circumference and the time-effect relationship were compared among the three groups.

RESULTS: There were no significant differences in tumor size, subcutaneous fat and arm circumference among the three groups (all P > 0.05). At week 4, food intake was significantly higher in the early mirtazapine treatment group than in the other two groups (both P < 0.05). The body weight (18.05 g ± 0.68 g) in the early mirtazapine treatment group was significantly higher than that in the control group (17.24 g ± 0.53 g, P < 0.05), but had no significant difference with that in the late mirtazapine treatment group (17.65 g ± 0.60 g, P > 0.05).

CONCLUSION: Early treatment with mirtazapine significantly improves food intake in the Gemcitabine-induced mild cachexia mouse model with pancreatic cancer, it can also postpone the processes of cachexia to some extent.

Fluoxetine counteracts the cognitive and cellular effects of 5-fluorouracil in the rat hippocampus by a mechanism of prevention rather than recovery

5-Fluorouracil (5-FU) is a cytostatic drug associated with chemotherapy-induced cognitive impairments that many cancer patients experience after treatment. Previous work in rodents has shown that 5-FU reduces hippocampal cell proliferation, a possible mechanism for the observed cognitive impairment, and that both effects can be reversed by co-administration of the antidepressant, fluoxetine. In the present study we investigate the optimum time for administration of fluoxetine to reverse or prevent the cognitive and cellular effects of 5-FU.

Male Lister-hooded rats received 5 injections of 5-FU (25 mg/kg, i.p.) over 2 weeks. Some rats were co-administered with fluoxetine (10 mg/kg/day, in drinking water) for 3 weeks before and during (preventative) or after (recovery) 5-FU treatment or both time periods (throughout). Spatial memory was tested using the novel location recognition (NLR) test and proliferation and survival of hippocampal cells was quantified using immunohistochemistry. 5-FU-treated rats showed cognitive impairment in the NLR task and a reduction in cell proliferation and survival in the subgranular zone of the dentate gyrus, compared to saline treated controls. These impairments were still seen for rats administered fluoxetine after 5-FU treatment, but were not present when fluoxetine was administered both before and during 5-FU treatment. The results demonstrate that fluoxetine is able to prevent but not reverse the cognitive and cellular effects of 5-FU. This provides information on the mechanism by which fluoxetine acts to protect against 5-FU and indicates when it would be beneficial to administer the antidepressant to cancer patients.

Oral administration of fluoxetine alters the proliferation/apoptosis balance of lymphoma cells and up-regulates T cell immunity in tumor-bearing mice

Antidepressants have a controversial role with regard to their influence on cancer and immunity. Recently, we showed that fluoxetine administration induces an enhancement of the T-cell mediated immunity in naïve mice, resulting in the inhibition of tumor growth. Here we studied the effects of fluoxetine on lymphoma proliferation/apoptosis and immunity in tumor bearing-mice. We found an increase of apoptotic cells (active Caspase-3(+)) and a decrease of proliferative cells (PCNA(+)) in tumors growing in fluoxetine-treated animals. In addition, differential gene expressions of cell cycle and death markers were observed. Cyclins D3, E and B were reduced in tumors from animals treated with fluoxetine, whereas the tumor suppressor p53 and the cell cycle inhibitors p15/INK4B, p16/INK4A and p27/Kip1 were increased. Besides, the expression of the antiapoptotic factor Bcl-2 and the proapoptotic factor Bad were lower and higher respectively in these animals. These changes were accompanied by increased IFN-γ and TNF-α levels as well as augmented circulating CD8(+) T lymphocytes in tumor-bearing mice treated with the antidepressant. Therefore, we propose that the up-regulation of T-cell mediated antitumor immunity may be contributing to the alterations of tumor cell proliferation and apoptosis thus resulting in the inhibition of tumor progression.

Antidepressants and breast and ovarian cancer risk: a review of the literature and researchers' financial associations with industry

Background

Antidepressant (AD) use has been purported to increase the risk of breast and ovarian cancer, although both epidemiological and pre-clinical studies have reported mixed results [1]–[6]. Previous studies in a variety of biomedical fields have found that financial ties to drug companies are associated with favorable study conclusions [7].

Methods and Findings

We searched English-language articles in MEDLINE, PsychINFO, the Science Citations Index and the Cochrane Central Register of Controlled Clinical Trials (through November 2010). A total of 61 articles that assessed the relationship between breast and ovarian cancer and AD use and articles that examined the effect of ADs on cell growth were included. Multi-modal screening techniques were used to investigate researchers' financial ties with industry. A random effects meta-analysis was used to pool the findings from the epidemiological literature. Thirty-three percent (20/61) of the studies reported a positive association between ADs and cancer. Sixty-seven percent (41/61) of the studies reported no association or antiproliferative effect. The pooled odds ratio for the association between AD use and breast/ovarian cancer in the epidemiologic studies was 1.11 (95% CI, 1.03–1.20). Researchers with industry affiliations were significantly less likely than researchers without those ties to conclude that ADs increase the risk of breast or ovarian cancer. (0/15 [0%] vs 20/46 [43.5%] (Fisher's Exact test P = 0.0012).

Conclusions

Both the pre-clinical and clinical data are mixed in terms of showing an association between AD use and breast and ovarian cancer. The possibility that ADs may exhibit a bi-phasic effect, whereby short-term use and/or low dose antidepressants may increase the risk of breast and ovarian cancer, warrants further investigation. Industry affiliations were significantly associated with negative conclusions regarding cancer risk. The findings have implications in light of the 2009 USPSTF guidelines for breast cancer screening and for the informed consent process.

Growth inhibitory efficacy of lycopene and β-carotene against androgen-independent prostate tumor cells xenografted in nude mice

SCOPE

In this study, we evaluated the efficacy of lycopene against the growth of prostate cancer in vivo.

METHODS AND RESULTS

Athymic nude mice were implanted subcutaneously with human androgen-independent prostate carcinoma PC-3 cells. They were supplemented with a low or a high dose of lycopene (4 and 16 mg/kg) and a single dose of β-carotene (16 mg/kg) twice a week for 7 wk. At the end of the experiment, both lycopene and β-carotene strongly inhibited the tumor growth, as evidenced by the decrease in tumor volume and tumor weight. High-dosage lycopene and β-carotene significantly decreased the expression of proliferating cell nuclear antigen in tumor tissues and increased the levels of insulin-like growth factor-binding protein-3 in plasma. In addition, high-dosage lycopene supplementation significantly decreased the vascular endothelial growth factor (VEGF) levels in plasma. In contrast, β-carotene supplementation significantly increased the VEGF levels, as compared with tumor control group.

CONCLUSION

Lycopene and β-carotene supplementation suppressed the growth of prostate tumor cells, and the effects are likely associated with reduction of proliferation (attenuation of proliferating cell nuclear antigen expression) and with interference of the insulin-like growth factor 1 signaling (increased plasma insulin-like growth factor-binding protein-3 levels). Furthermore, the inhibition of VEGF by lycopene suggests that the antitumor mechanisms of lycopene also involve anti-angiogenesis.

Megestrol acetate and mirtazapine for the treatment of unplanned weight loss in the elderly

A rising concern among clinicians is treatment of unplanned weight loss in the elderly, especially given the predicted growth of this population over the next few decades. Unexpected weight loss in the geriatric patient worsens overall health outcomes. A variety of pharmacotherapeutic options are available for treatment; however, evidence underlying their use is limited, and none has gained approval from the United States Food and Drug Administration for this indication. At present, no guidelines support the choice of one agent over another. Although several drug interventions have been employed for this problem, megestrol acetate and mirtazapine are becoming increasingly used for appetite stimulation. These drugs represent two feasible options for geriatric patients because of their generally favorable adverse-effect profiles and few drug interactions, but they are often misused. In a comprehensive search of the MEDLINE and International Pharmaceutical Abstracts databases, we identified all published reports on the use of megestrol acetate or mirtazapine for the treatment of weight loss and on any adverse events associated with these drugs. Special emphasis was placed on trials performed in an elderly population. Results were conflicting, most likely because of differing study designs and small numbers of patients. Megestrol acetate and mirtazapine appear to be effective for appetite stimulation and weight gain in some settings. However, applicability of the data to elderly individuals is unclear, and adverse events reported in a few of the trials and in case reports were not benign. Therefore, the use of megestrol acetate or mirtazapine for weight loss should be thoroughly evaluated on an individual basis. Pharmacotherapy should be used only after all underlying causes of weight loss are assessed and treated.