Amitriptyline induces mitophagy that precedes apoptosis in human HepG2 cells

Isogarcinol inhibits nasopharyngeal carcinoma growth through mitochondria-mediated autophagic cell death

BACKGROUND AND AIMS

Isogarcinol, a natural compound extracted from the fruits of Garcinia oblongifolia, has potential chemopreventive activity. This study aimed to elucidate the anti-tumor effects and mechanism of action of isogarcinol on nasopharyngeal carcinoma (NPC).

METHODS

Isogarcinol was isolated from Garcinia oblongifolia by using chromatographic separation. The anti-tumor effects of isogarcinol in NPC cells were tested by MTT assay, flow cytometry, wound healing assay, western blotting, transwell assay, colony formation assay, immunofluorescence, and transmission electron microscopy (TEM). The anti-tumor efficacy in vivo was evaluated in NPC cells xenograft models.

RESULTS

Functional studies revealed that isogarcinol inhibited the proliferation, colony formation, migration and invasion abilities of NPC cells in vitro. Isogarcinol caused mitochondrial damage to overproduce reactive oxygen species through reducing the mitochondrial membrane potential and ΔΨm. Isogarcinol also substantially inhibited NPC cells growth in a xenograft tumor model without any obvious toxicity when compared with paclitaxel (PTX). Mechanistic studies have illustrated that isogarcinol increased the Bax/Bcl-2 ratio, cleaved caspase-3, and cytoplasmic cytochrome C levels to induce mitochondrial apoptosis. The ROS overproduction by isogarcinol could suppress EMT pathway via decreasing the levels of p-Akt and Snail. Furthermore, isogarcinol promoted the conversion of LC3-Ⅰ to LC3-Ⅱ, but increased p62 level to block autophagic flux, resulting in the accumulation of damaged mitochondria to promote autophagic cell death in NPC cells.

CONCLUSION

This study provides a new theoretical foundation for the anti-tumor application of Garcinia oblongifolia and confirms that isogarcinol could be developed as a candidate drug for NPC treatment with low toxicity.

Antidepressants and Risk of Liver Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Previous results regarding the association between the antidepressants use and risk of liver cancer are controversial.

OBJECTIVE

This study aimed to assess whether antidepressants use increases liver cancer risk.

METHODS

We systematically searched several English and Chinese databases, including the Cochrane Library, MEDLINE, Embase, PsycINFO, Web of Science, CNKI, CQVIP database, Wanfang database, and SinoMed, and 3 clinical trial registration platforms through May 2022. Observational studies evaluating liver cancer risk in patients on antidepressants use were included, and the quality of studies was assessed using the Newcastle-Ottawa scale. A random-effects model was used to calculate the pooled effect estimates and 95% confidence intervals (CIs).

RESULTS

We included 11 studies with a total of 132 396 liver cancer cases. The meta-relative risk (RR) for liver cancer associated with antidepressants use was 0.72 (95% CI 0.59-0.86). In subgroup analyses, only selective serotonin reuptake inhibitors were negatively correlated with risk of liver cancer (RR 0.64, 95% CI 0.51-0.79); both dose subgroups ≤365cDDD (RR 0.77, 95% CI 0.69-0.85) and >365cDDD (RR 0.57, 95% CI 0.40-0.81) were associated with lower liver cancer risk; only in patients with chronic viral hepatitis, the use of antidepressants reduced liver cancer risk (RR 0.70, 95% CI 0.54-0.90).

CONCLUSIONS AND RELEVANCE

The result of the current meta-analysis shows antidepressants use is not associated with increased risk of liver cancer and appears to be correlated with decreased risk. However, the observed association needs to be verified by more powerful evidence from prospective, methodologically rigorous studies.

Polyacrylonitrile microfibers pose a significant threat to the early-stage survival of zebrafish

Microplastic pollution, especially microfibers (MFs), presents a critical global environmental challenge in natural water bodies. Yet, research on the toxic effects of MFs, particularly during early fish development, is limited. This study aimed to investigate MFs' toxic effects and mechanisms on early-stage zebrafish. Zebrafish embryos were exposed to varying concentrations of polyacrylonitrile microfibers (PanMfs) for 7 days. Results revealed PanMfs adhering to the embryos' surface, with higher concentrations accelerating heart rate and causing pericardial edema in post-hatching larvae. Larvae ingested PanMfs, leading to their accumulation in the intestines and increased levels of reactive oxygen species (ROS) and mitochondrial quantity. Notably, lipid metabolism and calcium ion related signaling pathways underwent significant changes. Low concentration MFs affected glycometabolism pathways, with potential roles for aldob and cacng1a, exhibiting pronounced increases in ROS levels. High concentration of MFs had the most profound impact on signal transduction-related pathways, and possibly triggering micromitophagy and apoptosis in zebrafish intestinal epithelial cells through the Kras/MAPK signaling pathway, with potential roles for kras and mapk9. Although ROS increase was somewhat alleviated, it resulted in decreased survival rates and restricted growth in high concentration of MFs group. These findings highlight the significant threat of MFs to the early survival of fish. MFs pollution prevention and control hold great significance in the conservation of fishery resources.

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.

The application of antidepressant drugs in cancer treatment

Antidepressants refer to psychotropic drugs which are used to treat mental illness with prominent emotional depression symptoms. It was reported that antidepressants had associated with anti-carcinogenic function which was associated with various signaling pathways and changing of microenvironment. Its mechanism includes cell apoptosis, antiproliferative effects, mitochondria-mediated oxidative stress, DNA damaging, changing of immune response and inflammatory conditions, and acting by inhibiting multidrug resistance of cancer cells. Accumulated studies showed that antidepressants influenced the metabolic pathway of tumor cells. This review summarized recent developments with the impacts and mechanisms of 10 kinds of antidepressants in carcinostasis. Antidepressants are also used in combination therapy with typical anti-tumor drugs which shows a synergic effect in anti-tumor. By contrast, the promotion roles of antidepressants in increasing cancer recurrence risk, mortality, and morbidity are also included. Further clinical experiments and mechanism analyses needed to be achieved. A full understanding of the underlying mechanisms of antidepressants-mediated anticarcinogenic effects may provide new clues for cancer prevention and clinical treatment.

Proton Motive Force Inhibitors Are Detrimental to Methicillin-Resistant Staphylococcus aureus Strains

Methicillin-resistant Staphylococcus aureus (MRSA) strains are tolerant of conventional antibiotics, making them extremely dangerous. Previous studies have shown the effectiveness of proton motive force (PMF) inhibitors at killing bacterial cells; however, whether these agents can launch a new treatment strategy to eliminate antibiotic-tolerant cells mandates further investigation. Here, using known PMF inhibitors and two different MRSA isolates, we showed that the bactericidal potency of PMF inhibitors seemed to correlate with their ability to disrupt PMF and permeabilize cell membranes. By screening a small chemical library to verify this correlation, we identified a subset of chemicals (including nordihydroguaiaretic acid, gossypol, trifluoperazine, and amitriptyline) that strongly disrupted PMF in MRSA cells by dissipating either the transmembrane electric potential (ΔΨ) or the proton gradient (ΔpH). These drugs robustly permeabilized cell membranes and reduced MRSA cell levels below the limit of detection. Overall, our study further highlights the importance of cellular PMF as a target for designing new bactericidal therapeutics for pathogens. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) emerged as a major hypervirulent pathogen that causes severe health care-acquired infections. These pathogens can be multidrug-tolerant cells, which can facilitate the recurrence of chronic infections and the emergence of diverse antibiotic-resistant mutants. In this study, we aimed to investigate whether proton motive force (PMF) inhibitors can launch a new treatment strategy to eliminate MRSA cells. Our in-depth analysis showed that PMF inhibitors that strongly dissipate either the transmembrane electric potential or the proton gradient can robustly permeabilize cell membranes and reduce MRSA cell levels below the limit of detection.

Energy metabolism as a target for cyclobenzaprine: A drug candidate against Visceral Leishmaniasis

Leishmaniases have a broad spectrum of clinical manifestations, ranging from a cutaneous to a progressive and fatal visceral disease. Chemotherapy is nowadays the almost exclusive way to fight the disease but limited by its scarce therapeutic arsenal, on its own compromised by adverse side effects and clinical resistance. Cyclobenzaprine (CBP), an FDA-approved oral muscle relaxant drug has previously demonstrated in vitro and in vivo activity against Leishmania sp., but its targets were not fully unveiled. This study aimed to define the role of energy metabolism as a target for the leishmanicidal mechanisms of CBP. Methodology to assess CBP leishmanicidal mechanism variation of intracellular ATP levels using living Leishmania transfected with a cytoplasmic luciferase. Induction of plasma membrane permeability by assessing depolarization with DiSBAC(2)3 and entrance of the vital dye SYTOX® Green. Mitochondrial depolarization by rhodamine 123 accumulation. Mapping target site within the respiratory chain by oxygen consumption rate. Reactive oxygen species (ROS) production using MitoSOX. Morphological changes by transmission electron microscopy. CBP caused on L. infantum promastigotes a decrease of intracellular ATP levels, with irreversible depolarization of plasma membrane, the collapse of the mitochondrial electrochemical potential, mild uncoupling of the respiratory chain, and ROS production, with ensuing intracellular Ca²⁺ imbalance and DNA fragmentation. Electron microscopy supported autophagic features but not a massive plasma membrane disruption. The severe and irreversible mitochondrial damage induced by CBP endorsed the bioenergetics metabolism as a relevant target within the lethal programme induced by CBP in Leishmania. This, together with the mild-side effects of this oral drug, endorses CBP as an appealing novel candidate as a leishmanicidal drug under a drug repurposing strategy.

Psychiatric drugs impact mitochondrial function in brain and other tissues

Mitochondria have been linked to the etiology of schizophrenia (SZ). However, studies of mitochondria in SZ might be confounded by the effects of pharmacological treatment with antipsychotic drugs (APDs) and other common medications. This review summarizes findings on relevant mitochondria mechanisms underlying SZ, and the potential impact of psychoactive drugs including primarily APDs, but also antidepressants and anxiolytics. The summarized data suggest that APDs impair mitochondria function by decreasing Complex I activity and ATP production and dissipation of the mitochondria membrane potential. At the same time, in the brains of patients with SZ, antipsychotic drug treatment normalizes gene expression modules enriched in mitochondrial genes that are decreased in SZ. This indicates that APDs may have both positive and negative effects on mitochondria. The available evidence suggests three conclusions i) alterations in mitochondria functions in SZ exist prior to APD treatment, ii) mitochondria alterations in SZ can be reversed by APD treatment, and iii) APDs directly cause impairment of mitochondria function. Overall, the mechanisms of action of psychiatric drugs on mitochondria are both direct and indirect; we conclude the effects of APDs on mitochondria may contribute to both their therapeutic and metabolic side effects. These studies support the hypothesis that neuronal mitochondria are an etiological factor in SZ. Moreover, APDs and other drugs must be considered in the evaluation of this pathophysiological role of mitochondria in SZ. Considering these effects, pharmacological actions on mitochondria may be a worthwhile target for further APD development.

Antidepressant use and hepatocellular carcinoma in patients with hepatitis C who had received interferon therapy: A population-based cohort study

BACKGROUND

Using data from the National Health Insurance (NHI) of Taiwan, we conducted a nationwide population-based cohort study to investigate the association between antidepressant (ATD) use and the risk of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV) who had received interferon (IFN) therapy.

METHODS

This study included a total of 274,952 HCV-infected patients without hepatitis B virus infection who were enrolled in the NHI program between January 1, 1997 and December 31, 2013. Among these patients, only 10,713 (age ≥18 years) had received IFN therapy between 2004 and 2008. Among the patients who had received IFN therapy, 2014 had received ATDs, and 8684 had not. A Cox proportional hazards regression model was applied after adjusting for age, sex, income, urbanization, medical comorbidity, and medication use.

RESULTS

Compared with non-ATD-treated patients, ATD-treated patients were more likely to receive a diagnosis of alcohol-related disease, diabetes mellitus (DM), hypertension, and hyperlipidemia. ATD-treated patients had a significantly lower incidence of HCC than non-ATD-treated patients (P = 0.0019). Female, older (age ≥50 years), and non-DM patients who had received cumulative high doses of ATDs had a significantly lower risk of HCC than non-ATD-treated patients. After adjustment, only high-dose selective serotonin reuptake inhibitor (SSRI) use was inversely associated with HCC risk (adjusted hazard ratio 0.37, 95% confidence interval 0.19-0.71, P = 0.0027).

CONCLUSIONS

Our study showed that ATD use, especially a relatively high cumulative dose of SSRIs, in HCV-infected patients who had received IFN was associated with reduced HCC risk. Future clinical studies are warranted to explore the underlying mechanisms and to apply them to newer direct-acting antiviral agent treatments.

Tricyclic antidepressant amitriptyline inhibits autophagic flux and prevents tube formation in vascular endothelial cells

Amitriptyline is a tricyclic antidepressant and an inhibitor of lysosomal acid sphingomyelinase (ASM). Amitriptyline is well known for its cardiovascular side effects and toxicity in psychiatric patients. However, the mechanisms underlying the cardiovascular side effects of amitriptyline remain largely undefined. This study aimed to determine the effects of amitriptyline on angiogenic capability of vascular endothelial cells in physiological settings and identify its mechanism of action. The ex vivo aortic ring angiogenesis and in vitro-cultured endothelial cell tube formation assay were used to assess the effects of amitriptyline on endothelial angiogenic capability. It was demonstrated that amitriptyline impaired the angiogenesis of aortic rings, which was similar to that found in aortic rings with haploinsufficiency of the ASM gene. In cultured mouse microvascular endothelial cells (MVECs), amitriptyline impaired the proliferation and tube formation under basal condition, which were accompanied by attenuated angiogenic signalling pathways such as endothelial nitric oxide synthase, Akt and Erk1/2 pathways. Mechanistically, amitriptyline inhibited autophagic flux without affecting autophagosome biogenesis at basal condition. ASM gene silencing or autophagy inhibition mimics the inhibitory effects of amitriptyline on endothelial cell proliferation and tube formation. Collectively, our data suggest that amitriptyline inhibits endothelial cell proliferation and angiogenesis via blockade of ASM-autophagic flux axis. It is implicated that the cardiovascular side effects of amitriptyline may be associated with its inhibitory action on physiological angiogenesis.

Is Autophagy Involved in the Diverse Effects of Antidepressants?

Autophagy has received increased attention as a conserved process governing cellular energy and protein homeostasis that is thus relevant in a range of physiological and pathophysiological conditions. Recently, autophagy has also been linked to depression, mainly through its involvement in the action of antidepressants. Some antidepressant drugs and psychotropic medication have been reported to exert beneficial effects in other diseases, for example, in cancer and neurodegenerative diseases. This review collates the evidence for the hypothesis that autophagy contributes to the effects of antidepressants beyond depression treatment.

Methods to Detect Loss of Lysosomal Membrane Integrity

Loss of lysosomal membrane integrity, often referred to as lysosomal membrane permeabilization (LMP), occurs in many instances of cell death either as an initiating or as an amplifying event. Currently, the best method for detecting LMP is the galectin puncta formation assay which can be used for a broad range of sample types, both fixed and live, is easy to perform, and highly sensitive. This method, which is similar to the widely used LC3 puncta formation assay for autophagy, is based on the translocation of galectins to damaged lysosomes resulting in a change from uniform to punctate staining pattern. Here, we provide protocols for the galectin puncta formation assay in fixed and live cells and for an alternative assay based on fluorescent dextran release from damaged lysosomes, which can be performed in parallel.

A Unified Approach to Targeting the Lysosome's Degradative and Growth Signaling Roles

Lysosomes serve dual roles in cancer metabolism, executing catabolic programs (i.e., autophagy and macropinocytosis) while promoting mTORC1-dependent anabolism. Antimalarial compounds such as chloroquine or quinacrine have been used as lysosomal inhibitors, but fail to inhibit mTOR signaling. Further, the molecular target of these agents has not been identified. We report a screen of novel dimeric antimalarials that identifies dimeric quinacrines (DQ) as potent anticancer compounds, which concurrently inhibit mTOR and autophagy. Central nitrogen methylation of the DQ linker enhances lysosomal localization and potency. An in situ photoaffinity pulldown identified palmitoyl-protein thioesterase 1 (PPT1) as the molecular target of DQ661. PPT1 inhibition concurrently impairs mTOR and lysosomal catabolism through the rapid accumulation of palmitoylated proteins. DQ661 inhibits the in vivo tumor growth of melanoma, pancreatic cancer, and colorectal cancer mouse models and can be safely combined with chemotherapy. Thus, lysosome-directed PPT1 inhibitors represent a new approach to concurrently targeting mTORC1 and lysosomal catabolism in cancer.Significance: This study identifies chemical features of dimeric compounds that increase their lysosomal specificity, and a new molecular target for these compounds, reclassifying these compounds as targeted therapies. Targeting PPT1 blocks mTOR signaling in a manner distinct from catalytic inhibitors, while concurrently inhibiting autophagy, thereby providing a new strategy for cancer therapy. Cancer Discov; 7(11); 1266-83. ©2017 AACR.See related commentary by Towers and Thorburn, p. 1218This article is highlighted in the In This Issue feature, p. 1201.

Florfenicol-induced Mitochondrial Dysfunction Suppresses Cell Proliferation and Autophagy in Fibroblasts

Florfenicol (FLO) is one of the most popular antibiotics used in veterinary clinic and aquaculture. FLO can inhibit both bacterial and mitochondrial protein synthesis. However, the effects of FLO on mitochondrial function and cellular homeostasis remain unclear. Here we show that FLO inhibits expression of mitochondrial DNA-encoded proteins, decreases mitochondrial membrane potential, and promotes generation of reactive oxygen species (ROS) in vitro. As a result, activities of mitochondrial respiratory chain complex I and IV and the cellular ATP level are decreased and mitochondrial morphology is damaged. FLO represses cell growth and proliferation by suppression of phosphorylation of p70S6K through AMPK/mTOR/p70S6K pathway. Furthermore, FLO also induces G0/G1 cell cycle arrest via increase of p21 levels through activating ROS/p53/p21 pathway. Moreover, the clearance of damaged mitochondria by autophagy is impaired, leading to cell proliferation inhibition and promotes cell senescence. In addition, FLO-induced upregulation of cytosolic p53 may contribute to mitophagy deficiency via regulation of Parkin recruitment. In summary, our data suggest that florfenicol is an inhibitor of mitochondrial protein synthesis that can induce noticeable cytotoxicity. Thus, these findings can be useful for guiding the proper use of FLO and the development of safe drugs.

Induction of mitophagy-mediated antitumor activity with folate-appended methyl-β-cyclodextrin

Mitophagy is the specific autophagic elimination system of mitochondria, which regulates cellular survival via the removal of damaged mitochondria. Recently, we revealed that folate-appended methyl-β-cyclodextrin (FA-M-β-CyD) provides selective antitumor activity in folate receptor-α (FR-α)-expressing cells by the induction of autophagy. In this study, to gain insight into the detailed mechanism of this antitumor activity, we focused on the induction of mitophagy by the treatment of FR-α-expressing tumor cells with FA-M-β-CyD. In contrast to methyl-β-cyclodextrin, FA-M-β-CyD entered KB cells, human epithelial cells from a fatal cervical carcinoma (FR-α (+)) through FR-α-mediated endocytosis. The transmembrane potential of isolated mitochondria after treatment with FA-M-β-CyD was significantly elevated. In addition, FA-M-β-CyD lowered adenosine triphosphate (ATP) production and promoted reactive oxygen species production in KB cells (FR-α (+)). Importantly, FA-M-β-CyD enhanced light chain 3 (LC3) conversion (LC3-I to LC3-II) in KB cells (FR-α (+)) and induced PTEN-induced putative kinase 1 (PINK1) protein expression, which is involved in the induction of mitophagy. Furthermore, FA-M-β-CyD had potent antitumor activity in BALB/c nu/nu mice xenografted with KB cells (FR-α (+)) without any significant side effects. Taken together, these findings demonstrate that the autophagic cell death elicited by FA-M-β-CyD could be associated with mitophagy induced by an impaired mitochondrial function.