The effect of antidepressants on immune function in mice

Antidepressants as Autophagy Modulators for Cancer Therapy

Cancer is a major global public health problem with high morbidity. Depression is known to be a high-frequency complication of cancer diseases that decreases patients' life quality and increases the mortality rate. Therefore, antidepressants are often used as a complementary treatment during cancer therapy. During recent decades, various studies have shown that the combination of antidepressants and anticancer drugs increases treatment efficiency. In recent years, further emerging evidence has suggested that the modulation of autophagy serves as one of the primary anticancer mechanisms for antidepressants to suppress tumor growth. In this review, we introduce the anticancer potential of antidepressants, including tricyclic antidepressants (TCAs), tetracyclic antidepressants (TeCAs), selective serotonin reuptake inhibitors (SSRIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs). In particular, we focus on their autophagy-modulating mechanisms for regulating autophagosome formation and lysosomal degradation. We also discuss the prospect of repurposing antidepressants as anticancer agents. It is promising to repurpose antidepressants for cancer therapy in the future.

Effects of chronic desipramine pretreatment on open field-induced suppression of blood natural killer cell activity and cytokine response depend on the rat's behavioral characteristics

Effects of 14 consecutive day exposure to desipramine (10mg/kg i.p.), by itself or following chronic open field (OF) exposure, on subsequent neuroimmunological effects of acute (30 min) OF stress and the involvement of individual differences in response to novelty or social position in the anti-depressive responsiveness were investigated. Chronic desipramine pretreatment did not protect against OF stress-induced suppression of blood anti-tumor natural killer cell activity but increased plasma interleukin-10 and decreased interferon-γ and corticosterone concentration. These effects were particularly dangerous for the animals with increased responsivity to stress (desipramine alone) or with low behavioral activity (desipramine after chronic stress).

Antidepressants: influence on cancer and immunity?

Two decades ago, it was hypothesized that antidepressants could alter the course of neoplastic diseases. However, contradictory findings indicated that antidepressants could either have carcinogenic properties or improve the disease outcome. Intriguingly, controversial results were reported on the action of antidepressant drugs on immune function. Further hypotheses proposed that antidepressants could indirectly affect the cancer prognosis through the modulation of antitumor activity. Here we review the literature in order to elucidate the influence of antidepressants on cancer and immunity.

Use of antidepressants and the risk of breast cancer: a meta-analysis

The goal of this study was to perform a meta-analysis to examine the association between the use of antidepressants (AD) and the risk of breast cancer. We searched the EMBASE and MEDLINE databases from inception through February 25, 2012, using search terms related to ADs and breast cancer. Two evaluators independently reviewed and selected articles and extracted data based on predetermined selection criteria. Pooled effect estimates were obtained by using random- and fixed effects meta-analyses. Of the 3,209 titles identified, 18 articles met the inclusion criteria. The overall risk of breast cancer did not increase among AD users [adjusted odds ratio (aOR) 1.02; 95 % CI 0.96-1.08]. Those who took tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) were not at increased risks of breast cancer. In subgroup meta-analyses, null associations were consistent across the type of AD, funding sources, the number of adjusted variables, medication dose, the ascertainment of exposure, and methodological quality. In subgroup analyses based on exposure duration, a marginal association was observed for the use of SSRIs < 1-2 years (aOR 1.10; 95 % CI 1.02-1.19). However, this effect was attenuated over time and those using SSRIs for more than 1-2 years had no elevated breast cancer risk. These results support the lack of a clinically meaningful association between AD use and the development of breast cancer and provide considerable reassurance. Given that the data collected to date do not support changing the current prescribing patterns for ADs, the important benefits of AD therapy must be considered.

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.

Antidepressant pharmacotherapy: focus on sex differences in neuroimmunopharmacological crossroads

Major depression is a stress-related disorder that shows a clear female preponderance. Sex differences in antidepressant response have been documented in both the clinical and experimental settings. It is of interest that antidepressant drugs exert critical immunotropic influences, mediated by direct and/or compensatory routes; these effects are not completely understood but comprise a matter of intensive investigation. Even though human studies have found only a few sex-related differences in the immunotropic effects of antidepressants, recent experimental evidence in the chronic mild stress model of depression points towards a sexually dimorphic neuroimmune playground in view of chronic antidepressant treatment. Herein, we provide a concise review regarding the effects of antidepressant pharmacotherapy on neuroimmune manifestations by concentrating on intriguing sex differences.

Breast cancer recurrence risk in relation to antidepressant use after diagnosis

BACKGROUND

While laboratory data suggest that antidepressants may promote mammary tumor growth, there has been little research investigating whether antidepressant use after breast cancer diagnosis is associated with the risk of breast cancer recurrence.

METHODS

We conducted a retrospective cohort study within Group Health, an integrated healthcare delivery system in Washington state. Women diagnosed with a first primary invasive, stage I, IIA, or IIB, unilateral breast carcinoma between 1990-1994 (aged>or=65 years) and 1996-1999 (aged>or=18 years) were eligible for the study (N=1306). Recurrence within 5-year of diagnosis was ascertained by medical chart review. We used the pharmacy database to identify antidepressant dispensings from Group Health pharmacies. We used multiple Cox regression to estimate the hazard ratio for recurrence and breast cancer mortality, comparing users and non-users of antidepressant medications. Results for recurrence were examined separately in users and non-users of tamoxifen.

RESULTS

We did not observe an association between antidepressant use after breast cancer diagnosis and the risk of recurrence either in general (hazard ratio for any antidepressant use: 0.8; 95% confidence interval: 0.5-1.4) or for specific types of antidepressant medication. Risk of death from breast cancer did not differ between non-users and users of antidepressants.

CONCLUSIONS

The results of this study suggest that women who use antidepressants after breast cancer diagnosis do not have an increased risk of recurrence or mortality.

Use of antidepressants and risk of lung cancer

OBJECTIVE

To evaluate the effect of antidepressant use on lung cancer risk.

METHODS

We conducted a case-control study nested in a cohort of patients 40-84 year-old in 1995-2004, without a prior diagnosis of cancer using The Health Improvement Network (THIN) database in the UK. Cases comprised 4,336 patients with a first diagnosis of primary lung cancer. A sample of 10,000 controls was frequency-matched to the cases for age, sex, and the calendar year of diagnosis. The index date for exposure definition was one year before the diagnosis for cases and one year before a random date for controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression models adjusted for potential confounders.

RESULTS

Selective serotonin reuptake inhibitor (SSRI) use during the year preceding the index date with treatment duration of at least one year had an OR of 0.59 (95% CI 0.41, 0.86). The corresponding OR was 1.23 (95% CI 0.96, 1.58) for tricyclic antidepressants (TCAs).

CONCLUSIONS

SSRI use did not increase the lung cancer risk and might be associated with a reduced risk. However, residual confounding might explain the apparent protective effect found for SSRI use, as well as the marginally elevated risk observed among TCA users.

Antidepressant use and breast cancer risk

BACKGROUND

Antidepressants are among the most commonly prescribed drugs in the United States. Laboratory studies suggest that because certain antidepressants increase prolactin levels that they may also increase breast cancer risk. However, human studies evaluating use of antidepressants in relation to breast cancer risk have yielded inconsistent results.

METHODS

A population-based case-control study consisting of 975 breast cancer cases 65-79 years of age diagnosed from 1997-1999 and 1007 age and residence-matched controls was conducted in western Washington State. Detailed information on antidepressant use was obtained through structured in-person interviews. Logistic regression was performed to analyze the relationship between antidepressant use and breast cancer risk.

RESULTS

Overall, there was no association between ever use of antidepressants and breast cancer risk (odds ratio [OR] = 1.2, 95% confidence interval [95% CI]: 0.9-1.6). When evaluated separately, tricyclic antidepressants (TCA), selective serotonin reuptake inhibitors (SSRI), and triazolopyridines were each not associated with breast cancer risk. However, risk varied by hormone receptor status. Compared to never users, ever users of SSRIs had elevated risks of progesterone receptor (PR) negative and estrogen receptor (ER) positive/PR-negative breast cancers (OR = 1.8, 95% CI: 1.1-3.6 and OR = 2.0, 95% CI: 1.1-3.8, respectively), but not of tumors with other hormone receptor profiles.

CONCLUSIONS

Based on these results and those of previous studies, there is limited evidence that any type of antidepressant use is associated with breast cancer risk overall. SSRIs may elevate risks of PR- and ER+/PR- tumors, though further studies are needed to confirm these associations.

Immune parameters in patients with anxiety or depression during psychotherapy

BACKGROUND

Numerous studies have described distinctive immunological findings in patients with depression. In contrast, only very little is known about the possible influence of anxiety disorders on the immune system. It is also unknown whether treatment with psychotherapy alone has any influence on immunological variations in patients with psychiatric disorders.

METHODS

We measured immunological and psychological parameters in patients with minor depression (N=10) or anxiety disorder (N=13) over an 8-week course of inpatient psychotherapy. Data for patients and a group of healthy controls (N=11) were recorded three times in 4-week intervals. A FACS analysis revealed the composition of lymphocyte subpopulations. The production of reactive oxygen species (ROS) by phagocytes was analyzed using lucigenin-enhanced chemiluminescence.

RESULTS

On admission, patients with anxiety disorder showed a markedly elevated ratio of CD4(+) (T helper) versus CD8(+) (T suppressor/cytotoxic) lymphocytes compared to healthy controls (P<0.001) and minor depressives (P<0.01). The increased ratio in patients with anxiety disorder could mainly be attributed to a reduced count in CD8(+) T cells compared to healthy controls (P<0.01) and depressives (P<0.05). There were no differences between patients with depression and healthy controls with respect to the CD4(+)/CD8(+) ratio. We did not observe any differences in the production of ROS by phagocytes in patients compared to healthy controls. The CD4(+)/CD8(+) ratio remained elevated in patients with anxiety disorders during the following 8 weeks. There were no significant changes in this parameter over the course of the inpatient treatment.

LIMITATIONS

As a pilot study on the immune status in patients with anxiety disorders, the study's main limitation is the relatively low number of patients observed.

CONCLUSIONS

In this study we demonstrated for the first time marked immunological changes in patients with anxiety disorders. In addition, our results provide preliminary evidence that these immunological variations are not reversible by an 8-week course of inpatient psychotherapy alone.

EFFECT OF THE ANTIDEPRESSANT MAPROTILINE ON CA2+ MOVEMENT AND PROLIFERATION IN HUMAN PROSTATE CANCER CELLS

1. The effect of maprotiline, an antidepressant, on human prostate cells is unclear. In the present study, the effect of maprotiline on [Ca2+]i and growth in PC3 human prostate cancer cells was measured using the fluorescent dyes fura-2 and tetrazolium, respectively. 2. Maprotiline caused a rapid, concentration-dependent increase in [Ca2+]i (EC50 = 200 micromol/L). The maprotiline-induced [Ca2+]i increase was reduced by removal of extracellular Ca2+ or pretreatment with nicardipine. 3. The maprotiline-induced Mn2+ influx-associated fura-2 fluorescence quench directly suggests that maprotiline caused Ca2+ influx. 4. In Ca(2+)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, caused a monophasic [Ca2+]i increase, after which the effects of maprotiline of increasing [Ca2+]i were abolished. In addition, pretreatment with maprotiline reduced a major portion of the thapsigargin-induced increase in [Ca2+]i. 5. U73122, an inhibitor of phospholipase C, abolished the ATP (but not maprotiline)-induced increase in [Ca2+]i. 6. Overnight incubation with 1-10 micromol/L maprotiline did not alter cell proliferation, although incubation with 30-50 micromol/L maprotiline decreased cell proliferation. 7, These findings suggest that maprotiline rapidly increases [Ca2+]i in human prostate cancer cells by stimulating both extracellular Ca2+ influx and intracellular Ca2+ release and that it may modulate cell proliferation in a concentration-dependent manner.

Use of antidepressant medications and the possible association with breast cancer risk. A review

BACKGROUND

Antidepressant medication use has dramatically increased over the past decade, particularly for the newer classes such as selective serotonin reuptake inhibitors. While there is no question about the usefulness of these medications, it is important to review animal and epidemiologic studies that have evaluated the association between antidepressant medication use and the risk of breast cancer.

METHODS

This paper reviews the scientific literature pertaining to the prevalence of and indications for antidepressant medication use, and the possible association between antidepressant medication use and breast cancer risk.

RESULTS

Antidepressant medications are most commonly indicated for depressive disorders, and are also used for other conditions (e.g., anxiety disorders, personality disorders, and pain). In addition, antidepressants may be an effective alternative to estrogen therapy for the alleviation of hot flashes among peri-/postmenopausal women. Several epidemiologic studies have reported that certain antidepressants may be associated with a slightly increased breast cancer risk; however, the literature remains inconsistent.

CONCLUSIONS

The possibility of an association between certain antidepressant medications and breast cancer risk has not been excluded, although further studies are needed before the body of scientific evidence can be conclusive. Evidence to date does not support a change in the current use of antidepressant medications.

Effects of imipramine on T cell subsets in olfactory bulbectomized mice

To elucidate the immunological outcome in antidepressant therapy, the effects of acute or chronic imipramine (IMP) treatment on T cell subsets were examined in sham-operated (SO) and olfactory bulbectomized (OB) mice. Olfactory bulbectomy decreased the ratio of Lyt2-positive suppressor T cells to L3T4-positive T helper cells. Acute IMP treatment did not exert any effect on the ratio in SO nor in OB mice. Chronic IMP administration was found to significantly increase the ratio in SO and OB mice and, as a result, the ratio was significantly higher in SO mice compared with the control, while the ratio was normalized in OB mice. The present study may be suggestive of the immune activation in depression and of the immunosuppressive effects of antidepressants.

The effect of repeated amitriptyline and desipramine administration on cytokine release in C57BL/6 mice

This study examines the effects of repeated amitriptyline and desipramine administration (10 mg/kg, IP) on the immunoreactivity of saline-injected C57BL/6 mice, as evaluated by the ability of splenocytes to reduce a tetrazolium salt to formazan (MTT test), to proliferate, and to produce cytokines, such as interleukin (IL)-1, IL-2, IL-4, IL-6, IL-10 and interferon gamma (IFN-gamma). Desipramine and amitriptyline administered for one or two weeks enhance the biochemical (estimated by MTT test) and proliferative activities of splenocytes. One and two weeks administration of desipramine significantly reduces the secretion of IL-4, an anti-inflammatory cytokine. Amitriptyline administration for four weeks stimulates the proliferative activity of splenocytes and enhances IL-2 bioactivity, whereas four weeks desipramine aministration does not change these parameters in comparison to saline treated control mice. Prolonged desipramine administration (seven and 28 days) significantly increased the bioactivity of IL-1. Four weeks of prolonged administration of amitriptyline and desipramine induces a significant increase in the secretion of IL-10, a cytokine with immunosuppressive and anti-inflammatory activities. The results show that the immunoregulatory effects of tricyclic antidepressants in C57BL/6 mice depend on the drugs used and on the duration of administration.

Antidepressant medications and risk for cancer

Antidepressants appear to promote tumor growth in experimental studies; however, results from epidemiologic studies are inconclusive. We used a population-based cohort study to estimate the incidence of cancer after antidepressant treatment in 39,807 adult users of antidepressants identified in the Prescription Database of the County of North Jutland, Denmark between January 1, 1989 and December 31, 1995. Information on cancer occurrence was obtained from the Danish Cancer Registry. We categorized exposure according to use of tricyclic antidepressants, tetracyclic antidepressants, selective serotonin reuptake inhibitors, or monoamine oxidase inhibitors. In the follow-up period beginning 1 year after first known prescription, there were 966 cancers among users of antidepressants; our population estimate suggested an expected number of 946 for an overall standardized incidence ratio of 1.0 (95% confidence interval = 1.0-1.1). Users of tricyclic antidepressants had an excess of non-Hodgkin's lymphoma, with the risk increasing with the number of prescriptions of tricyclic antidepressants. The standardized incidence ratio was 2.5 (95% confidence interval, 1.4-4.2) for those with five or more prescriptions. Our results provide little evidence that antidepressants promote cancer at other sites, except for a possible effect of tricyclic antidepressants and tetracyclic antidepressants on non-Hodgkin's lymphoma.

Effects of chronic mild stress (CMS) and imipramine administration, on spleen mononuclear cell proliferative response, serum corticosterone level and brain norepinephrine content in male mice

There is increasing evidence that stress and emotional reactions produce changes in various immune processes. These changes may be due to alterations of the stress responses endocrine and for autonomic mediating mechanisms. In order to study such effects, the impact of chronic mild stress (CMS) application, and of subsequent imipramine administration were studied on the spleen mononuclear cell proliferative response period. OFI strain male mice were subjected to 4 or 7 weeks of CMS. The effects of these treatments on serum corticosterone levels and hypothalamic and hippocampal norepinephrine (NE) contents were also assessed. Subjects submitted to CMS had a higher spleen mononuclear cell proliferative response after either treatment duration. Imipramine treatment diminished this response enhancement in CMS exposed animals, but did not alter the proliferative responses of control subjects. Serum corticosterone levels, as well as hypothalamic and hippocampal nonrepinephrine contents did not significantly vary between groups. Taken together, these results suggest that CMSs effects on immune reactivity are not related to serum glucocorticoids or NE changes in these locations associated with the hypothalamic-pituitary- adrenocortical (HPA) axis.

Depression and immunity: clinical factors and therapeutic course

While many reports describe associations between depressive disorders and altered immunity, findings have not been fully consistent. Diagnostic subtype, demographic factors such as age and gender, medical characteristics, and the immune measures selected for assessment may have contributed to the heterogeneous findings. In a study of 21 medically healthy young adults with major depression, we found, consistent with previous reports, evidence of increased lymphocyte activation to mitogen challenge and decreased natural killer (NK) cell numbers and function during acute depression. Fifteen subjects were followed longitudinally. T, CD4+, CD29+, and CD45RA+ lymphocytes and T-cell mitogen responses decreased significantly (P<0.05) during 6 weeks of pharmacotherapy and concurrent clinical improvement. There was no change in NK activity or CD56+ cells. The longitudinal effects appeared unrelated to tricyclic antidepressant levels. Changes in the immune system with short-term clinical improvement in depressed patients are not uniform providing further evidence that several mechanisms are involved in the altered immunity associated with clinical depression.

Influence of acute tryptophan depletion on mood and immune measures in healthy males

Depressive illness has been associated with variations of several aspects of immune functioning, as well as alterations of cytokine production in stimulated lymphocytes. In the present investigation we sought to determine whether pharmacologically-induced reductions of mood in healthy, male subjects would be associated with alterations in the levels of circulating IL-1 beta or IL-6 or to in vitro lymphocyte proliferation in response to T cell mitogens, PHA and Con A. Lowering tryptophan levels by means of a tryptophan-deficient amino acid mixture, which reduced plasma tryptophan and serotonin (5-HT) levels, produced a lowering of mood in a subset of male subjects (that had no personal or family history of depression) relative to subjects that received a balanced amino acid mixture. Correlational analyses revealed that the change of mood (particularly depression and anger) in subjects that received the tryptophan-free mixture was related to the extent of the tryptophan or 5-HT reductions. However, while fenfluramine administration resulted in recovery of tryptophan and 5-HT levels, this was not accompanied by recovery of mood. Furthermore, it was observed that the lowering of tryptophan levels and the reduced mood were not accompanied by variations of the cytokine levels or cell proliferation. Evidently, transient and modest alterations of 5-HT or mood induced by a tryptophan-free amino acid mixture were insufficient to promote variations of immune activity or circulating IL-1 beta or IL-6 levels. Even if depression were related to immune disturbances, the mood and 5-HT alterations associated with this type of manipulation may be too brief to promote immune changes comparable with those ordinarily associated with severe or chronic depressive illness.

Do antidepressants cause, promote, or inhibit cancers?

Do antidepressants cause, promote, or inhibit cancers?

OBJECTIVE

To review all human and experimental studies that examined the association of antidepressants with cancer or the effect of antidepressants on neoplastic growth.

METHODS

A search was conducted of MEDLINE for relevant articles published in English between 1976 and 1993.

RESULTS

Four human studies and nine experimental models were found. The human studies showed a transiently statistically significant positive association between amitriptyline and liver cancer and a negative association with pancreatic cancer; and that the antidepressants amitriptyline, nortriptyline, desipramine, and phenelzine may increase risk of breast cancer. Results of the experimental studies differed depending on which antidepressants were examined and which model was used. Amitriptyline was found to promote tumour growth, fluoxetine and clomipramine were reported to be both tumour promoters and antineoplastic agents, and imipramine and citalopram both demonstrated antineoplastic properties.

CONCLUSIONS

Further epidemiologic studies in humans are needed to determine which antidepressants cause, promote, or inhibit cancers.

The effect of chronic treatment with imipramine on the immunoreactivity of animals subjected to a chronic mild stress model of depression

A depression-like state was induced in Wistar rats by chronic (3-week) exposure to very mild, unpredictable stress, which led to diminished food consumption and diminished preference for sweet drinks (anhedonia). Anhedonia was then abolished by 5 weeks of daily administration of imipramine to the continually stressed animals. One day after the last drug injection and stressful event, a statistically significant decrease in the proliferative activity of splenocytes to Con A stimulation in vitro was observed in those animals. Eight weeks of stress (without antidepressant therapy) affected likewise, but in a less potent and non-significant manner, the activity of splenocytes. Administration of imipramine alone for a period of 5 weeks did not modify the activity of these cells.

Immune changes induced by electroconvulsive therapy (ECT)

There is a significant increase in the percentage and absolute number of activated lymphocytes (OKT10+, IL2R1+) after ECT treatment of major depressive disorder. There is an acute decrease in the absolute number of total lymphocytes, T8+ and Leu11+ cells one hour after a single ECT.

Immunological correlates of seasonal fluctuations in mood and behavior and their relationship to phototherapy

Immunological parameters were studied before and after phototherapy, with bright and dim light, in 38 individuals with a range of retrospectively reported seasonal changes in mood and behavior. There was a significant negative correlation between the degree of mood and behavioral difficulties in fall and winter (seasonality) and the total number of circulating natural killer cells. Changes in the numbers of circulating helper T cells correlated significantly with changes in mood following phototherapy. Moreover, mitogen-induced lymphocyte blastogenesis increased significantly after phototherapy, but there was no significant difference between the bright and dim light treatments. The results suggest that cellular immune function is associated with both seasonality and response to phototherapy.