In Vitro Identification and In Vivo Confirmation of Inhibitors for Sweet Potato Chlorotic Stunt Virus RNA Silencing Suppressor, a Viral RNase III

Sweet potato virus disease (SPVD), caused by synergistic infection of Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV), is responsible for substantial yield losses all over the world. However, there are currently no approved treatments for this severe disease. The crucial role played by RNase III of SPCSV (CSR3) as an RNA silencing suppressor during the viruses' synergistic interaction in sweetpotato makes it an ideal drug target for developing antiviral treatment. In this study, high-throughput screening (HTS) of small molecular libraries targeting CSR3 was initiated by a virtual screen using Glide docking, allowing the selection of 6,400 compounds out of 136,353. We subsequently developed and carried out kinetic-based HTS using fluorescence resonance energy transfer technology, which isolated 112 compounds. These compounds were validated with dose-response assays including kinetic-based HTS and binding affinity assays using surface plasmon resonance and microscale thermophoresis. Finally, the interference of the selected compounds with viral accumulation was verified in planta In summary, we identified five compounds belonging to two structural classes that inhibited CSR3 activity and reduced viral accumulation in plants. These results provide the foundation for developing antiviral agents targeting CSR3 to provide new strategies for controlling sweetpotato virus diseases.IMPORTANCE We report here a high-throughput inhibitor identification method that targets a severe sweetpotato virus disease caused by coinfection with two viruses (SPCSV and SPFMV). The disease is responsible for up to 90% yield losses. Specifically, we targeted the RNase III enzyme encoded by SPCSV, which plays an important role in suppressing the RNA silencing defense system of sweetpotato plants. Based on virtual screening, laboratory assays, and confirmation in planta, we identified five compounds that could be used to develop antiviral drugs to combat the most severe sweetpotato virus disease.

Abstract 2153: Ex vivo drug sensitivity testing of primary cells for precision cancer medicine

Introduction/Purpose:

Cancer therapy is increasingly moving towards individualized care and therapy, but there are still gaps between what is known and described on the molecular level about cancers and what is applied in the clinic. In an attempt to bridge the knowledge gap, we at the Institute for Molecular Medicine Finland (FIMM) have set up an Individualized Systems Medicine program that integrates clinical information, molecular profiling and functional information about individual patients’ cancers (Pemovska et al, Cancer Discov, 2013). Central to this program is the Drug Sensitivity and Resistance Testing (DSRT) where we functionally profile the responses of primary cancer cells to a comprehensive clinical oncology and signal transduction inhibitor drug collection of 528 compounds.

Methods:

Acoustic dispensing platforms are integral to the success of this profiling activity. We have to date produced approximately 3000 drug sets as dose response assay ready plates. The acoustic dispensing allows for making pre-drugged single drug plate sets and/or drug combination plates within hours after sampling of the cells. The plates are also readily sent to researchers anywhere in the world for running comparable assays at other sites. The drugging reproducibility is excellent generating results with correlations of 0.98 or higher in replicate assays. We have developed in-house software solutions to aid these processes: a script for quick creation of transfer list for combination plates and automated analysis pipelines with web-based software interfaces to enable the screening biologists to analyze the screening results effectively.

Results:

The results of these assays are used to explore and understand cancer biology in terms of druggability, functional heterogeneity and mechanism of drug response and resistance. The profiling data can be used to stratify and position the relevance of specific drugs in different diseases and has been used to identify novel clinically relevant activities of existing and investigational drugs (see e.g. Pemovska et al, Nature, 2015). This information is further utilized to establish hypotheses on drug combinations selectively targeting individual cancers and their predictive biomarkers, which can be explored in the clinic by our clinical collaborators to guide the treatment of the individual patient.

Conclusions:

In summary, we describe our platform for a functional drug sensitivity testing within our individualized cancer systems medicine program, which generates consistent biological and clinically relevant data.

Citation Format: Sergey G. Kuznetsov, Alexander Ianevski, Evgeny Kulessky, Karoliina Laamanen, Elina Lehtinen, Maria Nurmi, Swapnil Potdar, Jani Saarela, Katja Suomi, Laura Turunen, Krister Wennerberg, Päivi Tammela. Ex vivo drug sensitivity testing of primary cells for precision cancer medicine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2153.

Abstract 458: Precision systems medicine in acute myeloid leukemia: real-time translation of tailored therapeutic opportunities arising from ex-vivo drug sensitivity testing and molecular profiling

Acute myeloid leukemia (AML) is an aggressive disease of clonal hematopoietic progenitor cells. Here, we applied ex-vivo drug sensitivity and resistance testing on AML patient cells with 362 emerging and 153 approved cancer drugs together with genomic and transcriptomic profiling to identify and tailor therapies for patients with advanced disease. Ex-vivo testing with freshly isolated patient cells revealed cancer-specific efficacies of approved drugs in 97% of the 164 patient cases, including 47% of the cases with no actionable driver mutations. We identified 142 statistically significant associations between drug responses and somatic mutations, including increased sensitivity to JAK inhibitors in patients with NPM1 mutations. Transcriptomic profiles predicted drug responses better than genomics and helped to identify additional response markers, especially beyond mutations. For example, overexpression of HOX family genes was associated with sensitivity to JAK inhibitors in patients with NPM1 mutation. In a prospective study, we translated the functional drug response and molecular profile data to the clinic and suggested tailored therapy with targeted drugs for 26 relapsed or refractory AML patients. In an observational intervention study, acting on these recommendations resulted in a temporary complete clinical remission or leukemia-free state in 39% of the cases. In summary, we conclude that ex-vivo testing of drugs on patient AML cells i) revealed clinically actionable drug efficacies in almost all AML patients, including patients with no actionable mutations, ii) predicted cases with actionable driver mutations with no pharmacological dependency on the target, and iii) enabled real-time tailoring of therapy with 39% clinical response rate in chemorefractory advanced AML. Taken together, we believe this real-time systems medicine approach could become a powerful strategy for tailoring therapies for individual patients in the future.

Citation Format: Disha Malani, Ashwni Kumar, Bhagwan Yadav, Mika Kontro, Swapnil Potdar, Oscar Bruck, Säri Kytölä, Jani Saarela, Samuli Eldfors, Riikka Karjalainen, Muntasir M. Majumder, Imre Västrik, Pekka Ellonen, Matti Kankainen, Minna Suvela, Siv Knappila, Alun Parson, Aino Palva, Pirkko Mattila, Evgeny Kulesskiy, Laura Turunen, Karoliina Laamanen, Elina Lehtinen, Maria Nurmi, Katja Suomi, Astrid Muruimägi, Bjorn T. Gjertsen, Satu Mustjoki, Simon Anders, Maija Wolf, Tero Aittokallio, Krister Wennerberg, Caroline Heckman, Kimmo Porkka, Olli Kallioniemi. Precision systems medicine in acute myeloid leukemia: real-time translation of tailored therapeutic opportunities arising from ex-vivo drug sensitivity testing and molecular profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 458.

Abstract 3899: Discovery and clinical implementation of individualized therapies in acute myeloid leukemia based on ex vivo drug sensitivity testing and multi-omics profiling

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by multiple molecular subtypes and lack of effective targeted therapies. Here, we performed extensive molecular profiling and ex vivo drug testing with 515 approved and emerging cancer drugs on 164 AML patient samples. The aim was to i) assign individualized treatment options to advanced AML patients in real time, ii) explore drug response patterns across the molecular subtypes of AML and iii) identify opportunities to repurpose existing and emerging cancer drugs.

Bone marrow samples (n=164) from 129 consecutive AML patients and 17 healthy donors were studied from the Helsinki University Hospital and the Haukeland University Hospital, Bergen. Mononuclear cells were resuspended either in mononuclear cell medium (MCM) or stroma conditioned medium (CM) and tested for drug sensitivity and resistance as previously described (PMID: 24056683) and studied by exome and transcriptome sequencing. The study protocol allowed us to return data to the clinician for consideration of novel treatment options. For the meta-analysis of associations between drug responses and molecular and clinical parameters, Wilcoxon signed ranked test and logistic regression were applied.

Clustering of all patient samples based on ex vivo drug response patterns in both media types identified 7 distinct functional groups of AML. For example, a subgroup of samples was highly resistant to chemotherapeutics and all targeted drugs except BCL-2 inhibitors. The differences in drug responses in the two media types highlighted the importance of assay conditions for ex vivo drug testing. Strong clustering of several drugs in the same drug classes was often observed as well as clustering across different classes, for example between BET (JQ1, I-BET151, birabresib) and MEK (trametinib, cobimetinib) inhibitors. About 24 percent of the FLT3 negative AML patients manifested strong ex vivo sensitivity to glucocorticoids, highlighting a potential drug repositioning opportunity in this subset of AML patients. Overall, we identified 320 significant associations between drugs and mutated driver genes including association between NPM1 mutation and sensitivity to JAK inhibitors.

Altogether, targeted treatment opportunities were clinically tested in 25 occasions in chemorefractory AML patients. The tailored clinical therapy led to transient complete remission or leukemia free state in 36% (9/25) of these cases.

In conclusion, we discovered and clinically implemented individualized therapeutic options for AML patients, which resulted in a 36% clinical responses in a non-randomized proof-of-concept study. The associations identified between ex-vivo drug response and driver mutations provided novel drug repositioning opportunities in specific molecular subtypes.

Citation Format: Disha Malani, Ashwini Kumar, Bhagwan Yadav, Mika Kontro, Swapnil Potdar, Oscar Brück, Sari Kytölä, Jani Saarela, Samuli Eldfors, Poojitha Ojamies, Karjalainen Riikka, Muntasir Mamun Majumder, Imre Västrik, Pekka Ellonen, Matti Kankainen, Minna Suvela, Siv Knappila, Alun Parson, Aino Palva, Pirkko Mattila, Evgeny Kulesskiy1, Laura Turunen, Karoliina Laamanen, Elina Lehtinen, Piia Mikkonen, Maria Nurmi, Sanna Timonen, Astrid Murumägi, Bjorn Tore Gjersten, Satu Mustjoki, Tero Aittokallio, Krister Wennerberg, Simon Anders, Maija Wolf, Caroline Heckman, Kimmo Porkka, Olli Kallioniemi. Discovery and clinical implementation of individualized therapies in acute myeloid leukemia based on ex vivo drug sensitivity testing and multi-omics profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3899.

Isolation of bifidobacteria for blood group secretor status targeted personalised nutrition

Background

Currently, there is a constant need to find microbial products for maintaining or even improving host microbiota balance that could be targeted to a selected consumer group. Blood group secretor status, determining the ABO status, could be used to stratify the consumer group.

Objective

We have applied a validated upper intestinal tract model (TIM-1) and culturing methods to screen potential probiotic bacteria from faeces of blood secretor and non-secretor individuals.

Design

Faecal samples from healthy volunteers were pooled to age- and sex-matched secretor and non-secretor pools. Faecal pools were run through separate TIM-1 simulations, and bacteria were cultivated from samples taken at different stages of simulations for characterisation.

Results

Microbes in secretor pool survived the transit through TIM-1 system better than microbes of non-secretor pool, especially bifidobacteria and anaerobes were highly affected. The differences in numbers of bifidobacteria and lactobacilli isolates after plate cultivations and further the number of distinct RAPD-genotypes was clearly lower in non-secretor pool than in secretor pool.

Conclusions

In the present study, we showed that microbiota of secretor and non-secretor individuals tolerate gastrointestinal conditions differently and that a combination of gastrointestinal simulations and cultivation methods proved to be a promising tool for isolating potentially probiotic bacteria.

A novel strategy for inducing enhanced mucosal HIV-1 antibody responses in an anti-inflammatory environment

Prophylactic vaccination against HIV-1 sexual transmission will probably require antibody elicitation at genital mucosal surfaces. However, HIV-1 envelope glycoprotein (Env)-based antigens are weakly immunogenic, particularly when applied mucosally. The polyanion PRO 2000 is safe for human vaginal application, and thus may represent a potential formulating agent for vaginal delivery of experimental vaccine immunogens. Based upon its biochemical properties, we hypothesized that PRO 2000 might enhance mucosal immunogenicity of HIV-1 envelope glycoprotein (Env)-based antigens, promoting local and systemic immune responses. Vaginal immunization with Env-PRO 2000 resulted in significantly increased titres of Env-specific mucosal IgA and IgG in mice and rabbits, respectively, compared to Env alone, revealing modest but significant mucosal adjuvant activity for PRO 2000. In vitro, PRO 2000 associated with Env, protecting the glycoprotein from proteolytic degradation in human vaginal lavage. Unexpectedly, PRO 2000 antagonized TLR4 activation, suppressing local production of inflammatory cytokines. Since inflammation-mediated recruitment of viral target cells is a major risk factor in HIV-1 transmission, the immune modulatory and anti-inflammatory activities of PRO 2000 combined with its intravaginal safety profile suggests promise as an HIV-1 mucosal vaccine formulating agent.

A microparticle enzyme immunoassay to measure sirolimus

Measurement of sirolimus as a guide to therapy is widely accepted. Since the commercial introduction of the drug, the only method available to measure blood concentrations has been high-performance liquid chromatography (HPLC). Only a limited number of centers have the facilities to perform this technique and, as a result, the measurement of the drug has been performed in central laboratories, often some distance from the clinical centers. This article describes a single-center assessment of a new immunoassay to measure sirolimus, including a comparison between immunoassay results and a chromatographic technique. Calibration accuracy was good, reproducibility at 11 ng/mL was better than 6%, and sensitivity was better than 2 ng/mL; all these parameters are appropriate for routine clinical use. There was a mean positive bias of almost 20% for the measurement of sirolimus in clinical samples from kidney transplant patients receiving the drug, compared with HPLC. This bias was most likely due to cross-reactivity with metabolites of the drug and was of the order noted when an earlier configuration of this immunoassay was used in clinical practice. We conclude that, despite the analytical bias, this immunoassay offers a viable alternative to the use of HPLC and would be an assay suitable for implementing at local centers.