Selective serotonin reuptake inhibitors are clinically prescribed antidepressants that act by increasing the local concentrations of neurotransmitters at synapses and in extracellular spaces via ...blockade of the serotonin transporter. Here we report X-ray structures of engineered thermostable variants of the human serotonin transporter bound to the antidepressants sertraline, fluvoxamine, and paroxetine. The drugs prevent serotonin binding by occupying the central substrate-binding site and stabilizing the transporter in an outward-open conformation. These structures explain how residues within the central site orchestrate binding of chemically diverse inhibitors and mediate transporter drug selectivity.
The serotonin transporter (SERT) terminates serotonergic signalling through the sodium- and chloride-dependent reuptake of neurotransmitter into presynaptic neurons. SERT is a target for ...antidepressant and psychostimulant drugs, which block reuptake and prolong neurotransmitter signalling. Here we report X-ray crystallographic structures of human SERT at 3.15 Å resolution bound to the antidepressants (S)-citalopram or paroxetine. Antidepressants lock SERT in an outward-open conformation by lodging in the central binding site, located between transmembrane helices 1, 3, 6, 8 and 10, directly blocking serotonin binding. We further identify the location of an allosteric site in the complex as residing at the periphery of the extracellular vestibule, interposed between extracellular loops 4 and 6 and transmembrane helices 1, 6, 10 and 11. Occupancy of the allosteric site sterically hinders ligand unbinding from the central site, providing an explanation for the action of (S)-citalopram as an allosteric ligand. These structures define the mechanism of antidepressant action in SERT, and provide blueprints for future drug design.
The serotonin transporter (SERT) regulates neurotransmitter homeostasis through the sodium- and chloride-dependent recycling of serotonin into presynaptic neurons
. Major depression and anxiety ...disorders are treated using selective serotonin reuptake inhibitors-small molecules that competitively block substrate binding and thereby prolong neurotransmitter action
. The dopamine and noradrenaline transporters, together with SERT, are members of the neurotransmitter sodium symporter (NSS) family. The transport activities of NSSs can be inhibited or modulated by cocaine and amphetamines
, and genetic variants of NSSs are associated with several neuropsychiatric disorders including attention deficit hyperactivity disorder, autism and bipolar disorder
. Studies of bacterial NSS homologues-including LeuT-have shown how their transmembrane helices (TMs) undergo conformational changes during the transport cycle, exposing a central binding site to either side of the membrane
. However, the conformational changes associated with transport in NSSs remain unknown. To elucidate structure-based mechanisms for transport in SERT we investigated its complexes with ibogaine, a hallucinogenic natural product with psychoactive and anti-addictive properties
. Notably, ibogaine is a non-competitive inhibitor of transport but displays competitive binding towards selective serotonin reuptake inhibitors
. Here we report cryo-electron microscopy structures of SERT-ibogaine complexes captured in outward-open, occluded and inward-open conformations. Ibogaine binds to the central binding site, and closure of the extracellular gate largely involves movements of TMs 1b and 6a. Opening of the intracellular gate involves a hinge-like movement of TM1a and the partial unwinding of TM5, which together create a permeation pathway that enables substrate and ion diffusion to the cytoplasm. These structures define the structural rearrangements that occur from the outward-open to inward-open conformations, and provide insight into the mechanism of neurotransmitter transport and ibogaine inhibition.
Open radical cystectomy (ORC) has proven to be an important component in the treatment of high-risk bladder cancer (BCa). ORC surgical morbidity remains high; therefore, minimally invasive surgical ...techniques have been introduced in an attempt to improve patient outcomes.
To compare cancer outcomes in BCa patients managed with ORC or robotic-assisted radical cystectomy (RARC).
A prospective, randomized trial was completed between 2010 and 2013. Patients were randomized to ORC/pelvic lymphadenectomy (PLND) or RARC/PLND, with all undergoing open/extracorporeal urinary diversion. Median follow-up was 4.9 (IQR: 3.9–5.9) yr after surgery among surviving patients.
Secondary outcomes to the trial included recurrence-free, cancer-specific, and overall survival.
The trial randomized 118 patients who underwent RC/PLND and urinary diversion. Sixty were randomized to RARC and 58 to ORC. Four RARC-assigned patients refused randomization and received ORC; however, an intention to treat analysis was performed. No differences were observed in recurrence (hazard ratio HR: 1.27; 95% confidence interval CI: 0.69–2.36; p=0.4) or cancer-specific survival (p=0.4). No difference in overall survival was observed (p=0.8). However, the pattern of first recurrence demonstrated a nonstatistically significant increase in metastatic sites for those undergoing ORC (sub-HR sHR: 2.21; 95% CI: 0.96–5.12; p=0.064) and a greater number of local/abdominal sites in the RARC-treated patients (sHR: 0.34; 95% CI: 0.12–0.93; p=0.035). The major limitation to this study is that the trial was not powered to determine differences in cancer recurrences, survival outcomes, or patterns of recurrence.
The secondary outcomes from our randomized trial did not definitively demonstrate differences in cancer outcomes in patients treated with ORC or RARC. However, differences in observed patterns of first recurrence highlight the need for future studies.
Of 118 patients randomly assigned to undergo radical cystectomy/pelvic lymphadenectomy and urinary diversion, half were assigned to open surgery and half to robot-assisted techniques. We found no difference in risk of recurring or dying of bladder cancer between the two groups.
In this secondary analysis of cancer outcomes from our randomized controlled trial, we did not find a difference in overall recurrence rates and cancer-specific survival between open radical cystectomy and robot-assisted radical cystectomy for high-risk bladder cancer. Variations in patterns of recurrence require further study.
Bladder cancer is the fifth most prevalent cancer in the U.S., yet is understudied, and few laboratory models exist that reflect the biology of the human disease. Here, we describe a biobank of ...patient-derived organoid lines that recapitulates the histopathological and molecular diversity of human bladder cancer. Organoid lines can be established efficiently from patient biopsies acquired before and after disease recurrence and are interconvertible with orthotopic xenografts. Notably, organoid lines often retain parental tumor heterogeneity and exhibit a spectrum of genomic changes that are consistent with tumor evolution in culture. Analyses of drug response using bladder tumor organoids show partial correlations with mutational profiles, as well as changes associated with treatment resistance, and specific responses can be validated using xenografts in vivo. Our studies indicate that patient-derived bladder tumor organoids represent a faithful model system for studying tumor evolution and treatment response in the context of precision cancer medicine.
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•Efficient generation of a biobank of patient-derived bladder cancer organoids•Organoids recapitulate the histological and molecular spectrum of human bladder cancer•Bladder tumor organoids display clonal evolution in culture and as xenografts•Drug response of organoids can be validated in xenografts
A biobank of patient-derived bladder tumor organoids faithfully recapitulates features of human cancer and enables analysis of clonal evolution and drug responses.
Abstract Background Open radical cystectomy (ORC) and urinary diversion in patients with bladder cancer (BCa) are associated with significant perioperative complication risk. Objective To compare ...perioperative complications between robot-assisted radical cystectomy (RARC) and ORC techniques. Design, setting, and participants A prospective randomized controlled trial was conducted during 2010 and 2013 in BCa patients scheduled for definitive treatment by radical cystectomy (RC), pelvic lymph node dissection (PLND), and urinary diversion. Patients were randomized to ORC/PLND or RARC/PLND, both with open urinary diversion. Patients were followed for 90 d postoperatively. Intervention Standard ORC or RARC with PLND; all urinary diversions were performed via an open approach. Outcome measurements and statistical analysis Primary outcomes were overall 90-d grade 2–5 complications defined by a modified Clavien system. Secondary outcomes included comparison of high-grade complications, estimated blood loss, operative time, pathologic outcomes, 3- and 6-mo patient-reported quality-of-life (QOL) outcomes, and total operative room and inpatient costs. Differences in binary outcomes were assessed with the chi-square test, with differences in continuous outcomes assessed by analysis of covariance with randomization group as covariate and, for QOL end points, baseline score. Results and limitations The trial enrolled 124 patients, of whom 118 were randomized and underwent RC/PLND. Sixty were randomized to RARC and 58 to ORC. At 90 d, grade 2–5 complications were observed in 62% and 66% of RARC and ORC patients, respectively (95% confidence interval for difference, −21% to −13%; p = 0.7). The similar rates of grade 2–5 complications at our mandated interim analysis met futility criteria; thus, early closure of the trial occurred. The RARC group had lower mean intraoperative blood loss ( p = 0.027) but significantly longer operative time than the ORC group ( p < 0.001). Pathologic variables including positive surgical margins and lymph node yields were similar. Mean hospital stay was 8 d in both arms (standard deviation, 3 and 5 d, respectively; p = 0.5). Three- and 6-mo QOL outcomes were similar between arms. Cost analysis demonstrated an advantage to ORC compared with RARC. A limitation is the setting at a single high-volume, referral center; our findings may not be generalizable to all settings. Conclusions This trial failed to identify a large advantage for robot-assisted techniques over standard open surgery for patients undergoing RC/PLND and urinary diversion. Similar 90-d complication rates, hospital stay, pathologic outcomes, and 3- and 6-mo QOL outcomes were observed regardless of surgical technique. Patient summary Of 118 patients with bladder cancer who underwent radical cystectomy, pelvic lymph node dissection, and urinary diversion, half were randomized to open surgery and half to robot-assisted laparoscopic surgery. We compared the rate of complications within 90 d after surgery for the open group versus the robotic group and found no significant difference between the two groups. Trial Registration ClinicalTrials.gov identifier NCT01076387 , www.clinicaltrials.gov.
To investigate genomic differences between urothelial carcinomas of the upper tract (UTUC) and bladder (UCB), with a focus on defining the clonal relatedness of temporally distinct tumors.
We ...prospectively sequenced tumors and matched germline DNA using targeted next-generation sequencing methods. The cohort included 195 UTUC patients and 454 UCB patients. For a subgroup of 29 patients with UTUC and a history of a subsequent UCB, both tumors were analyzed to assess their clonal relatedness.
With the progression to higher UTUC clinical state, there were fewer alterations in the RTK/RAS pathway but more alterations in TP53/MDM2. Compared with UCB,
and
were less frequently altered in UTUC (26% vs. 46%, 3% vs. 20%, 8% vs. 19%, respectively;
< 0.001), whereas
and
were more frequently altered (40% vs. 26%, 12% vs. 4%, respectively;
< 0.001). On the basis of an integrated analysis of tumor mutational burden, MSIsensor score and mutational signature, 7.2% of UTUC tumors were classified as MSI-high/MMR-deficient (MSI-H/dMMR). The risk of bladder recurrence after UTUC was significantly associated with mutations in
and
. Comparison of UCB with corresponding UTUC tumors from the same patient supports their clonal relatedness.
UTUC and UCB exhibit significant differences in the prevalence of common genomic alterations. In individual patients with a history of both tumors, UCB and UTUC were always clonally related. Genomic characterization of UTUC provides information regarding the risk of bladder recurrence and can identify tumors associated with Lynch syndrome.
Tumor-infiltrating immune cells have been linked to prognosis and response to immunotherapy; however, the levels of distinct immune cell subsets and the signals that draw them into a tumor, such as ...the expression of antigen presenting machinery genes, remain poorly characterized. Here, we employ a gene expression-based computational method to profile the infiltration levels of 24 immune cell populations in 19 cancer types.
We compare cancer types using an immune infiltration score and a T cell infiltration score and find that clear cell renal cell carcinoma (ccRCC) is among the highest for both scores. Using immune infiltration profiles as well as transcriptomic and proteomic datasets, we characterize three groups of ccRCC tumors: T cell enriched, heterogeneously infiltrated, and non-infiltrated. We observe that the immunogenicity of ccRCC tumors cannot be explained by mutation load or neo-antigen load, but is highly correlated with MHC class I antigen presenting machinery expression (APM). We explore the prognostic value of distinct T cell subsets and show in two cohorts that Th17 cells and CD8
T/Treg ratio are associated with improved survival, whereas Th2 cells and Tregs are associated with negative outcomes. Investigation of the association of immune infiltration patterns with the subclonal architecture of tumors shows that both APM and T cell levels are negatively associated with subclone number.
Our analysis sheds light on the immune infiltration patterns of 19 human cancers and unravels mRNA signatures with prognostic utility and immunotherapeutic biomarker potential in ccRCC.
Depression is a common mental disorder. The standard medical treatment is the selective serotonin reuptake inhibitors (SSRIs). All characterized SSRIs are competitive inhibitors of the serotonin ...transporter (SERT). A non-competitive inhibitor may produce a more favorable therapeutic profile. Vilazodone is an antidepressant with limited information on its molecular interactions with SERT. Here we use molecular pharmacology and cryo-EM structural elucidation to characterize vilazodone binding to SERT. We find that it exhibits non-competitive inhibition of serotonin uptake and impedes dissociation of
Himipramine at low nanomolar concentrations. Our SERT structure with bound imipramine and vilazodone reveals a unique binding pocket for vilazodone, expanding the boundaries of the extracellular vestibule. Characterization of the binding site is substantiated with molecular dynamics simulations and systematic mutagenesis of interacting residues resulting in decreased vilazodone binding to the allosteric site. Our findings underline the versatility of SERT allosteric ligands and describe the unique binding characteristics of vilazodone.
Provide evidence- and expert-based recommendations for optimal use of imaging in advanced prostate cancer. Due to increases in research and utilization of novel imaging for advanced prostate cancer, ...this guideline is intended to outline techniques available and provide recommendations on appropriate use of imaging for specified patient subgroups.
An Expert Panel was convened with members from ASCO and the Society of Abdominal Radiology, American College of Radiology, Society of Nuclear Medicine and Molecular Imaging, American Urological Association, American Society for Radiation Oncology, and Society of Urologic Oncology to conduct a systematic review of the literature and develop an evidence-based guideline on the optimal use of imaging for advanced prostate cancer. Representative index cases of various prostate cancer disease states are presented, including suspected high-risk disease, newly diagnosed treatment-naïve metastatic disease, suspected recurrent disease after local treatment, and progressive disease while undergoing systemic treatment. A systematic review of the literature from 2013 to August 2018 identified fully published English-language systematic reviews with or without meta-analyses, reports of rigorously conducted phase III randomized controlled trials that compared ≥ 2 imaging modalities, and noncomparative studies that reported on the efficacy of a single imaging modality.
A total of 35 studies met inclusion criteria and form the evidence base, including 17 systematic reviews with or without meta-analysis and 18 primary research articles.
One or more of these imaging modalities should be used for patients with advanced prostate cancer: conventional imaging (defined as computed tomography CT, bone scan, and/or prostate magnetic resonance imaging MRI) and/or next-generation imaging (NGI), positron emission tomography PET, PET/CT, PET/MRI, or whole-body MRI) according to the clinical scenario.
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