SLC6A4 expression and anti-proliferative responses to serotonin transporter ligands chlomipramine and fluoxetine in primary B-cell malignancies

Serotonin Receptors in Myocardial Infarction: Friend or Foe?

Acute myocardial infarction (AMI) is one of the leading causes of death worldwide and treatment costs pose a major burden on the global health care system. Despite the variety of treatment options, individual recovery can be still poor and the mortality rate, especially in the first few years after the event, remains high. Therefore, intense research is currently focused on identifying novel target molecules to improve the outcome following AMI. One of the potentially interesting targets is the serotonergic system (5-HT system), not at least because of its connection to mental disorders. It is known that patients suffering from AMI have an increased risk of developing depression and vice versa. This implicates that the 5-HT system can be affected in response to AMI and might thus represent a target structure for patients' treatment. This review aims to highlight the importance of the 5-HT system after AMI by describing the role of individual serotonin receptors (5-HTR) in the regulation of physiological and pathophysiological responses. It particularly focuses on the signaling pathways of the serotonin receptors 1, 2, 4, and 7, which are expressed in the cardiovascular system, during disease onset, and the following remodeling process. This overview also emphasizes the importance of the 5-HT system in AMI etiology and highlights 5-HTRs as potential treatment targets.

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.

In silico analysis of a SLC6A4 G100V mutation in lung cancers

SLC6A4 is a serotonin re-uptake transporter which has been a target for anti-depressant therapies but recently some mutations have been described in cancer cells. Here, we characterize mutations in SLC6A4 that appear in cancer cells. We employed several validated computational and artificial intelligence algorithms to characterize the mutations. We identified a previously uncharacterized G100V mutation in lung cancers. In sillico structural analysis reveals that this mutation may affect SLC6A4 ligand binding and subsequently its function. We also identified several other mutations that may affect the structure of the protein. This preliminary analysis highlights the role of SLC6A4 in human cancers.

Antitumoral Effects of Tricyclic Antidepressants: Beyond Neuropathic Pain Treatment

Simple Summary

Tricyclic antidepressants (TCAs) are old and known therapeutic agents whose good safety profile makes them good candidates for drug repurposing. As the relevance of nerves in cancer development and progression is being unveiled, attention now turns to the use of nerve-targeting drugs, such as TCAs, as an interesting approach to combat cancer. In this review, we discuss current evidence about the safety of TCAs, their application to treat neuropathic pain in cancer patients, and in vitro and in vivo demonstrations of the antitumoral effects of TCAs. Finally, the results of ongoing clinical trials and future directions are discussed.

Abstract

Growing evidence shows that nerves play an active role in cancer development and progression by altering crucial molecular pathways and cell functions. Conversely, the use of neurotropic drugs, such as tricyclic antidepressants (TCAs), may modulate these molecular signals with a therapeutic purpose based on a direct antitumoral effect and beyond the TCA use to treat neuropathic pain in oncology patients. In this review, we discuss the TCAs’ safety and their central effects against neuropathic pain in cancer, and the antitumoral effects of TCAs in in vitro and preclinical studies, as well as in the clinical setting. The current evidence points out that TCAs are safe and beneficial to treat neuropathic pain associated with cancer and chemotherapy, and they block different molecular pathways used by cancer cells from different locations for tumor growth and promotion. Likewise, ongoing clinical trials evaluating the antineoplastic effects of TCAs are discussed. TCAs are very biologically active compounds, and their repurposing as antitumoral drugs is a promising and straightforward approach to treat specific cancer subtypes and to further define their molecular targets, as well as an interesting starting point to design analogues with increased antitumoral activity.

Apoferritin: a potential nanocarrier for cancer imaging and drug delivery

Introduction: As a protein-based biomaterial for potential cancer targeting delivery, apoferritin has recently attracted interest.Areas covered: In this review, we discuss the development of this cage-like protein as an endogenous nanocarrier that can hold molecules in its cavity. We present the specific characterizations and formulations of apoferritin nanocarriers, and outline the recent progress of the protein as an appropriate tumor-delivery vehicle in different therapeutic strategies to treat solid tumors. Finally, we propose how the application for cancer drug repurposing delivery within apoferritin could expand cancer treatment in the future.Expert opinion: Being a ubiquitous iron storage protein that exists in many living organisms, apoferritin is promising as a cancer tumor-targeting nanocarrier. By exploiting its versatility, apoferritin could be used for cancer repurposed drug delivery and could reduce the high cost of new drug discovery development and shorten the formulation process.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

Novel vitamin D analogues; cytotoxic and anti-proliferative activity against a diffuse large B-cell lymphoma cell line and B-cells from healthy donors

Calcitriol (1,25-dihydroxyvitamin D₃, 1,25D₃) and vitamin D side-chain modified analogs (VDAs) have gained considerable attention as potential drugs in the treatment of acute myeloid leukemia (AML), yet studies of the impact of 1,25D₃ and VDAs upon other haematological malignancies are more limited. To address this gap in knowledge, we have examined the action of 1,25D₃ and VDAs on a human cell line (DOHH2, K422) typifying diffuse large B-cell lymphoma (DLBCL) and also peripheral blood B-cells isolated from healthy donors. 1,25D₃ and certain VDAs displayed moderate cytotoxic and pro-apoptotic actions upon DLBCL cells. 1,25D₃ and VDAs (100nM) caused the death of approximately 40% DOHH2 cells after 24h stimulation, similar to their impact on HL-60 cells (acute myeloid leukaemia cell line). In addition, 1,25D₃ and VDAs displayed concentration and time-dependent anti-proliferative actions upon stimulated B-cells from healthy donors. The VDAs inhibited proliferation by approximately 30%. Hence VDAs may offer therapeutic potential for the treatment of DLBCL or conditions benefitted by B-cell depletion.

Serotonin uptake is largely mediated by platelets versus lymphocytes in peripheral blood cells

The serotonin transporter (SERT), a primary target for many antidepressants, is expressed in the brain and also in peripheral blood cells. Although platelet SERT function is well accepted, lymphocyte SERT function has not been definitively characterized. Due to their small size, platelets often are found in peripheral blood mononuclear cell preparations aimed at isolating lymphocytes, monocytes, and macrophages. The presence of different cells makes it difficult to assign SERT expression and function to specific cell types. Here, we use flow cytometry and IDT307, a monoamine transporter substrate that fluoresces after uptake into cells, to investigate SERT function in lymphocyte and platelet populations independently, as well as simultaneously without prior isolation. We find that murine lymphocytes exhibit temperature-dependent IDT307 transport but uptake is independent of SERT. Lack of measurable SERT function in lymphocytes was corroborated by chronoamperometry using serotonin as a substrate. When we examined rhesus and human mixed blood cell populations, we found that platelets, and not lymphocytes, were primary contributors to SERT function. Overall, these findings indicate that lymphocyte SERT function is minimal. Moreover, flow cytometry, in conjunction with the fluorescent transporter substrate IDT307, can be widely applied to investigate SERT in platelets from populations of clinical significance.

Evidence for functional trace amine associated receptor-1 in normal and malignant B cells

Following the observation that dopaminergic components are present in normal and malignant B cells, we now provide evidence that they additionally express the functionally related trace amine-associated receptor-1 (TAAR1). Immunodetectable TAAR1 was found in lines derived from a broad range of B-cell malignancy; and in tonsillar B cells, particularly when activated. L3055 Burkitt's lymphoma cells were shown to respond to prototypical TAAR1 agonists in cytotoxicity assays with features of apoptotic death evident; normal B cells were somewhat less sensitive to the agonists. These data raise the possibility that TAAR1 may have therapeutic relevance to leukemia, lymphoma, and wider B-cell pathologies.

Enhancing the anti-lymphoma potential of 3,4-methylenedioxymethamphetamine ('ecstasy') through iterative chemical redesign: mechanisms and pathways to cell death

While 3,4-methylenedioxymethamphetamine (MDMA/'ecstasy') is cytostatic towards lymphoma cells in vitro, the concentrations required militate against its translation directly to a therapeutic in vivo. The possibility of 'redesigning the designer drug', separating desired anti-lymphoma activity from unwanted psychoactivity and neurotoxicity, was therefore mooted. From an initial analysis of MDMA analogues synthesized with a modified α-substituent, it was found that incorporating a phenyl group increased potency against sensitive, Bcl-2-deplete, Burkitt's lymphoma (BL) cells 10-fold relative to MDMA. From this lead, related analogs were synthesized with the 'best' compounds (containing 1- and 2-naphthyl and para-biphenyl substituents) some 100-fold more potent than MDMA versus the BL target. When assessed against derived lines from a diversity of B-cell tumors MDMA analogues were seen to impact the broad spectrum of malignancy. Expressing a BCL2 transgene in BL cells afforded only scant protection against the analogues and across the malignancies no significant correlation between constitutive Bcl-2 levels and sensitivity to compounds was observed. Bcl-2-deplete cells displayed hallmarks of apoptotic death in response to the analogues while BCL2 overexpressing equivalents died in a caspase-3-independent manner. Despite lymphoma cells expressing monoamine transporters, their pharmacological blockade failed to reverse the anti-lymphoma actions of the analogues studied. Neither did reactive oxygen species account for ensuing cell death. Enhanced cytotoxic performance did however track with predicted lipophilicity amongst the designed compounds. In conclusion, MDMA analogues have been discovered with enhanced cytotoxic efficacy against lymphoma subtypes amongst which high-level Bcl-2--often a barrier to drug performance for this indication--fails to protect.

MicroRNA in the regulation and expression of serotonergic transmission in the brain and other tissues

In addition to transcriptional regulation, the translation of protein-coding genes is modulated by MicroRNA-binding miRNAs (miRNAs), which have emerged to fulfil important roles in the control and expression of serotonergic transmission. Thus, miR-96 and miR-510 inhibit the translation of serotonin (5-HT)(1B) receptors and 5-HT(3E) receptor subunits respectively, and their susceptibility to repression is modified by polymorphisms in the 3'-UTR (miRNA-binding) regions of their mRNAs. Contrasting susceptibility of human subjects to miRNA-induced alterations in the translation of cerebral 5-HT(1B) receptors and intestinal 5-HT(3E) receptor subunits is related to differential aggressive behaviour and incidence of irritable bowel syndrome, respectively. Fluoxetine promotes the biogenesis of miR-16, leading to translational repression of 5-HT transporters in mouse serotonergic neurones. While the precise mechanism of action of fluoxetine is uncertain, studies of Aplysia have shown that 5-HT inhibits the generation of miR-124, thereby promoting de-repression of CREB and facilitation of synaptic plasticity. Interestingly, 5-HT(2C) receptors harbour a miRNA (miR-448) in their 4th intron that - oppositely to 5-HT(2C) sites - reduces adipocyte differentiation. Finally, interactions amongst 5-HT and miRNAs control processes of bone formation, as well as growth, motility and survival of tumours. The present article discusses the functionally and clinically important interplay amongst miRNAs and serotoninergic mechanisms in the brain, peripheral organs and cancerous tissue.

ChemProt: a disease chemical biology database

Systems pharmacology is an emergent area that studies drug action across multiple scales of complexity, from molecular and cellular to tissue and organism levels. There is a critical need to develop network-based approaches to integrate the growing body of chemical biology knowledge with network biology. Here, we report ChemProt, a disease chemical biology database, which is based on a compilation of multiple chemical–protein annotation resources, as well as disease-associated protein–protein interactions (PPIs). We assembled more than 700 000 unique chemicals with biological annotation for 30 578 proteins. We gathered over 2-million chemical–protein interactions, which were integrated in a quality scored human PPI network of 428 429 interactions. The PPI network layer allows for studying disease and tissue specificity through each protein complex. ChemProt can assist in the in silico evaluation of environmental chemicals, natural products and approved drugs, as well as the selection of new compounds based on their activity profile against most known biological targets, including those related to adverse drug events. Results from the disease chemical biology database associate citalopram, an antidepressant, with osteogenesis imperfect and leukemia and bisphenol A, an endocrine disruptor, with certain types of cancer, respectively. The server can be accessed at http://www.cbs.dtu.dk/services/ChemProt/.