Patient-Derived Tumor Organoids for Guidance of Personalized Drug Therapies in Recurrent Glioblastoma.

An obstacle to effective uniform treatment of glioblastoma, especially at recurrence, is genetic and cellular intertumoral heterogeneity. Hence, personalized strategies are necessary, as are means to stratify potential targeted therapies in a clinically relevant timeframe. Functional profiling of drug candidates against patient-derived glioblastoma organoids (PD-GBO) holds promise as an empirical method to preclinically discover potentially effective treatments of individual tumors. Here, we describe our establishment of a PD-GBO-based functional profiling platform and the results of its application to four patient tumors. We show that our PD-GBO model system preserves key features of individual patient glioblastomas in vivo. As proof of concept, we tested a panel of 41 FDA-approved drugs and were able to identify potential treatment options for three out of four patients; the turnaround from tumor resection to discovery of treatment option was 13, 14, and 15 days, respectively. These results demonstrate that this approach is a complement and, potentially, an alternative to current molecular profiling efforts in the pursuit of effective personalized treatment discovery in a clinically relevant time period. Furthermore, these results warrant the use of PD-GBO platforms for preclinical identification of new drugs against defined morphological glioblastoma features.

Personalized functional profiling using ex-vivo patient-derived spheroids points out the potential of an antiangiogenic treatment in a patient with a metastatic lung atypical carcinoid.

Lung carcinoids are neuroendocrine tumors representing 1 to 2% of lung cancers. This study outlines the case of a patient with a metastatic lung atypical carcinoid who presented with a pleural effusion and progression of liver metastases after developing resistance to conventional treatments. Personalized functional profiling (PFP), i.e. drug screening, was performed in ex-vivo spheroids obtained from the patient's liver metastasis to identify potential therapeutic options. The drug screening results revealed cediranib, an antiangiogenic drug, as a hit drug for this patient, from a library of 66 Food and Drug Administration (FDA)-approved and investigational drugs. Based on the PFP results and the reported evidence of clinical efficacy of bevacizumab and capecitabine combination in gastro-intestinal neuroendocrine tumors, this combination was given to the patient. Four months later, the pleural effusion and pleura carcinosis regressed and the liver metastasis did not progress. The patient experienced 2 years of a stable disease under the PFP-guided personalized treatment.

High-throughput drug screening using the Ebola virus transcription- and replication-competent virus-like particle system.

The massive epidemic of Ebola virus disease (EVD) in West Africa, followed in recent months by two outbreaks in the Democratic Republic of the Congo, underline the importance of this severe disease. Because Ebola virus (EBOV) must be manipulated under biosafety level 4 (BSL4) containment, the discovery and development of virus-specific therapies have been hampered. Recently, a transient transfection-based transcription- and replication competent virus-like particle (trVLP) system was described, enabling modeling of the entire EBOV life cycle under BSL2 conditions. Using this system, we optimized the condition for bulk co-transfection of multiple plasmids, developed a luciferase reporter-based assay in 384-well microtiter plates, and performed a high-throughput screening (HTS) campaign of an 8,354-compound collection consisting of U.S. Food & Drug Administration (FDA) -approved drugs, bioactives, kinase inhibitors, and natural products in duplicates. The HTS achieved a good signal-to-background ratio with a low percent coefficient of variation resulting in Z' = 0.7, and data points were reproducible with R2 = 0.89, indicative of a robust assay. After applying stringent hit selection criteria of ≥70% EBOV trVLP inhibition and ≥70% cell viability, 381 hits were selected targeting early, entry, and replication steps and 49 hits targeting late, maturation, and secretion steps in the viral life cycle. Of the total 430 hits, 220 were confirmed by dose-response analysis in the primary HTS assay. They were subsequently triaged by time-of-addition assays, then clustered and ranked according to their chemical structures, biological functions, therapeutic index, and maximum inhibition. Several novel drugs have been identified to very efficiently inhibit EBOV. Interestingly, most showed pharmacological activity in treatments for central nervous system-related diseases. We developed and screened an HTS assay using the novel EBOV trVLP system. Newly identified inhibitors are useful tools to study the poorly understood EBOV life cycle. In addition, they also provide opportunities to either repurpose FDA-approved drugs or develop novel viral interventions to combat EVD.

Intracellular protein target detection by quantum dots optimized for live cell imaging.

Imaging of specific intracellular target proteins in living cells has been of great challenge and importance for understanding intracellular events and elucidating various biological phenomena. Highly photoluminescent and water-soluble semiconductor nanocrystal quantum dots (QDs) have been extensively applied to various cellular imaging applications due to the long-term photostability and the tunable narrow emission spectra with broad excitation. Despite the great success of various bioimaging and diagnostic applications, visualization of intracellular targets in live cells still has been of great challenge. Nonspecific binding, difficulty of intracellular delivery, or endosomal trapping of nanosized QDs are the main reasons to hamper specific target binding in live cells. In this context, we prepared the polymer-coated QDs (pcQD) of which the surface was optimized for specific intracellular targeting in live cells. Efficient intracellular delivery was achieved through PEGylation and subsequent cell penetrating peptide (i.e., TAT) conjugation to the pcQD in order to avoid significant endosomal sequestration and to facilitate internalization of the QDs, respectively. In this study, we employed HEK293 cell line overexpressing endothelin A receptor (ET(A)R), a family of G-protein coupled receptor (GPCR), of which the cytosolic c-terminal site is genetically engineered to possess green fluorescent protein (GFP) as our intracellular protein target. The fluorescence signal of the target protein and the well-defined intracellular behavior of the GPCR help to evaluate the targeting specificity of QDs in living cells. To test the hypothesis that the TAT-QDs conjugated with antibody against intracellular target of interest can find the target, we conjugated anti-GFP antibody to TAT-PEG-pcQD using heterobifunctional linkers. Compared to the TAT-PEG-pcQD, which was distributed throughout the cytoplasm, the antiGFP-functionalized TAT-PEG-pcQD could penetrate the cell membrane and colocalize with the GFP. An agonist (endothelin-1, ET-1) treatment induced GFP-ET(A)R translocation into pericentriolar region, where the GFP also significantly colocalized with antiGFP-TAT-PEG-pcQD. These results demonstrate that stepwise optimization of PEG-pcQD conjugation with both a cell penetrating peptide and an antibody against a target of interest allows specific binding to the intracellular target protein with minimized nonspecific binding.