Characterization of cytotoxic actions of tricyclic antidepressants on human HT29 colon carcinoma cells

https://doi.org/10.1016/j.ejphar.2006.04.053Get rights and content

Abstract

Preclinical studies have suggested that the long-term use of antidepressants may result in the initiation and/or promotion of tumor in the gastrointestinal tract. However, a possible relationship between the use of antidepressants and the production of colon cancer has not yet been confirmed, and hence requires to be further investigated. To address this issue, the effects of antidepressants on the proliferation of colorectal tumor cells were examined using human HT29 colon carcinoma cells, and tricyclic antidepressant, such as imipramine, desipramine and amitriptyline, were shown to reduce the cell viability in a manner dependent on the time exposing to these drugs. In addition to these drugs, a selective serotonin reuptake inhibitor fluoxetine, but not a monoamine oxidase inhibitor tranylcypromine, caused the reduction of cell viability, similar in extent to that caused by imipramine. Further studies showed that desipramine caused the apoptotic cell death, which could be prevented by neither catalase, reduced-form glutathione (GSH), nor N-acetylcysteine (NAC), without accompanying the disruption of mitochondrial membrane potential within the cells and the release of cytochrome c into the cell cytoplasm. Moreover, desipramine caused the arrest of cell-cycle progression at either G0/G1-phase or G2/M-phase, which might be depending upon the drug concentration. Thus, these results suggest that tricyclic antidepressants may be cytotoxic, and induce the non-oxidative apoptotic death of human HT29 colon carcinoma cells probably through a non-mitochondrial pathway associated with the cell-cycle progression.

Introduction

Tricyclic antidepressants, such as imipramine, desipramine and amitriptyline, are commonly prescribed for depression, and selective serotonin reuptake inhibitors, fluoxetine and paroxetine, are recently introduced as effective drugs to the medication for depressive mood disorders. In such treatments, patients are usually having medication for long period, and hence there is great risk of these drugs inducing unexpected adverse effects during their long-term use. In particular, the question of whether antidepressants can initiate and/or promote tumor growth in patients and experimental animals has been raised, and the clinical and basic studies on a possible connection between antidepressant use and cancer risk have been carried out. Consequently, the case-control studies have suggested that the increased risk of breast cancer may be associated with the use of antidepressants, particularly genotoxic tricyclic antidepressants (Cotterchio et al., 2000, Sharpe et al., 2002). On the contrary, several studies have provided evidence against the association of antidepressant use with cancer risk (Coogan et al., 2000, Dalton et al., 2000, Dublin et al., 2002, Wang et al., 2001, Weiss et al., 1998). On the other hand, preclinical studies have shown that antidepressants have either no effect, stimulatory effect, or inhibitory effect on the growth of tumors implanted in rodents (Abdul et al., 1995, Bendele et al., 1992, Brandes et al., 1992, Freire-Garabal et al., 1998, Lin et al., 1999). Thus, these previous studies have only provided inconsistent or contradictory evidence, and hence the question regarding the association between antidepressant use and cancer risk still remains to be elucidated. More recently, the analyses of scientific reports in oncology and epidemiology have also shown that the link is questionable but deserving of further investigation on their genotoxic actions (see review; Sternbach, 2003).

Cells have been isolated from different-types of tumors originated from various tissues and organs of different species, and widely used as an in vitro model system for the assessment of tumor growth, and hence the cytotoxic actions of various chemicals and natural substances on tumor cells in culture have been studied as a primary screening for their antitumor activities. As such studies, the direct actions of antidepressants on the growth of various tumor cells have recently been examined, and antidepressants have been shown to cause the apoptotic death of malignant tumor cells (Gavrilova-Ruch et al., 2002, Koch et al., 2003, Serafeim et al., 2003, Slamon and Pentreath, 1998, Slamon and Pentreath, 2000, Slamon et al., 2001, Xia et al., 1999, Xia et al., 1998). In contrast, these drugs have been reported to protect tumor cells against the apoptotic death, and also shown to cause either the stimulatory effect or no notable effect on the proliferation of tumor cells in vitro (Li et al., 2003, Li and Luo, 2002, Volpe et al., 2003). These studies have been carefully carried out, and hence it seems possible that their inconsistent results may be mainly attributed to the difference in tumor cell lines used. Then, we anticipate that it is meaningful as a preclinical study to investigate a potential effects of antidepressants on particular tumor using an appropriate cell line.

Since antidepressants are orally administered to depressive patients, it seems conceivable that these drugs may directly contact with epithelial cells or tumor cells in the gastrointestinal tract for long period, thus resulting in the initiation and/or promotion of tumors with a considerably large probability. Previously, tricyclic antidepressants have been shown to cause the stimulation of cell proliferation in rat intestinal crypt epithelium and the promotion of experimental carcinogenesis in rat colon (Iishi et al., 1993, Tutton and Barkla, 1989), and these studies are thought to suggest that the long-term use of antidepressants may be associated somewhat with the initiation of tumors in the gastrointestinal tract. However, the relationship between the antidepressant use and the risk of colorectal tumors has not yet been fully elucidated because of the inconsistent results of clinical and preclinical studies. Even the direct actions of these drugs on tumor cell growth have been still uncertain. Therefore, it seemed necessary to further investigate the effects of antidepressants on tumor cells, particularly the direct actions of these drugs on the growth of colon cancer cells in culture. Then, to obtain a clue to understanding somewhat the contradiction and inconsistency of the experimental results reported previously, we carried out the in vitro model experiments using human HT29 colon carcinoma cells.

Section snippets

Materials

Human HT29 colon adenocarcinoma cells (HTB-38) were obtained from the American Type Culture Collection (Rockville, MD, USA). Antidepressants, neutral red solution, reduced-form glutathione (GSH), N-acetylcysteine (NAC), catalase, rhodamine-123, digitonin, and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) were obtained from Sigma Chemical Co. (St. Louis, MO, USA). TACS Annexin V-FITC Apoptosis Detection Kit was obtained from R&D Systems, Inc. (Minneapolis, MN, USA). Monoclonal mouse anti-human

Cytotoxic actions of antidepressants on HT29 cells

To examine the direct effects of antidepressants on malignant colorectal tumor cells, human HT29 colon carcinoma cells were exposed to these drugs at the concentrations of 50 μM for 24 h, and the cell viability was determined by measuring the uptake of neutral red into these cells. As shown in Fig. 1, the viability of HT29 cells was reduced by exposing to tricyclic antidepressants, such as imipramine, desipramine and amitriptyline. In addition to these tricyclic antidepressants, a selective

Discussion

Direct actions of antidepressants on human HT29 colon carcinoma cells were examined as an in vitro model experiment for investigating their possible influence on the growth of malignant colorectal tumors. Tricyclic antidepressants, such as imipramine, desipramine and amitriptyline, were shown to cause their cytotoxic actions on these cells in culture (Fig. 1). In addition to these tricyclic antidepressants, fluoxetine, one of the selective serotonin reuptake inhibitors, was shown to cause the

References (44)

  • A. Serafeim et al.

    Selective serotonin reuptake inhibitors directly signal for apoptosis in biopsy-like Burkitt lymphoma cells

    Blood

    (2003)
  • N.D. Slamon et al.

    Antioxidant defense against antidepressants in C6 and 1321N1 cells

    Chem.-Biol. Interact.

    (2000)
  • M. Ueno et al.

    SN-38 induces cell cycle arrest and apoptosis in human testicular cancer

    Eur. Urol.

    (2002)
  • P.S. Wang et al.

    Antidepressant use and the risk of breast cancer: a non-association

    J. Clin. Epidemiol.

    (2001)
  • C. Agarwal et al.

    Silibinin upregulates the expression of cyclin-dependent kinase inhibitors and causes cell cycle arrest and apoptosis in human colon carcinoma HT-29 cells

    Oncogene

    (2003)
  • R.A. Bendele et al.

    Carcinogenicity studies of fluoxetine hydrochloride in rats and mice

    Cancer Res.

    (1992)
  • L.J. Brandes et al.

    Stimulation of malignant growth in rodents by antidepressant drugs at clinically relevant doses

    Cancer Res.

    (1992)
  • F.P. Bymaster et al.

    Fluoxetine, but not other selective serotonin uptake inhibitors, increases norepinephrine and dopamine extracellular levels in prefrontal cortex

    Psychopharmacology

    (2002)
  • P.F. Coogan et al.

    Risk of ovarian cancer according to use of antidepressants, phenothiazines, and benzodiazepines (United States)

    Cancer Causes Control

    (2000)
  • M. Cotterchio et al.

    Antidepressant medication use and breast cancer risk

    Am. J. Epidemiol.

    (2000)
  • S.O. Dalton et al.

    Antidepressant medications and risk for cancer

    Epidemiology

    (2000)
  • S. Dublin et al.

    Risk of epithelial ovarian cancer in relation to use of antidepressants, benzodiazepines, and other centrally acting medications

    Cancer Causes Control

    (2002)
  • Cited by (77)

    • Fluoxetine exposure for more than 2 days decreases the neuronal plasticity mediated by CRMP2 in differentiated PC12 cells

      2020, Brain Research Bulletin
      Citation Excerpt :

      The selective serotonin reuptake inhibitor fluoxetine (FLU) reduces cell death in PC12 cells and hippocampus-derived cell line (Chiou et al., 2006; Kolla et al., 2005). However, it has been shown that FLU and other antidepressants exacerbate cell death in HT22 immortalized hippocampal neurons, PC12 cells, human neuroblastoma cell line and human colon carcinoma cells (Arimochi and Morita, 2006; Bartholomä et al., 2002; Levkovitz et al., 2005). Therefore, antidepressants, including FLU, may exert a cyto-protective effect or exacerbate cell damage, which is contradictory and rarely studied.

    View all citing articles on Scopus
    View full text