Assessment Of Drug Sensitivity Research Articles

Ex vivo assessment of chemotherapy sensitivity of colorectal cancer peritoneal metastases.

Patients with peritoneal metastasis from colorectal cancer (PMCRC) may have a chance of cure when treated with cytoreductive surgery (CRS) combined with heated intraperitoneal chemotherapy (HIPEC)1–5. Choice of chemotherapy for HIPEC has been based on knowledge of its systemic effects, pharmacokinetics, technical feasibility, hyperthermic efficacy enhancement, and tolerance6–8. Selection of cancer drugs for treatment based on phenotypical assessment of patient cancer cell drug sensitivity ex vivo is one approach to personalized cancer treatment. One technique for this is the fluorometric microculture cytotoxicity assay (FMCA) that has been used in drug development and for the development of personalized cancer medicine9–16. This study investigated whether ex vivo assessment of drug sensitivity by the FMCA provides predictive information in terms of peritoneal recurrence-free survival (PRFS) and overall survival (OS) in patients treated with CRS and HIPEC for isolated PMCRC. The patient cohort for this study was from a prospectively maintained institutional database at the Uppsala University Hospital, a tertiary care unit for PMCRC in Uppsala, Sweden. Patients with PMCRC treated with CRS and HIPEC have been registered since 2003. Ex vivo drug sensitivity testing using the FMCA started in April 2007. Thus, consecutive patients treated with CRS and HIPEC for PMCRC from April 2007 to October 2018 were considered for providing data for this report. Patients underwent HIPEC with either single-drug oxaliplatin, mitomycin C, or irinotecan, or a combination of oxaliplatin and irinotecan. HIPEC was performed in an open manner according to the coliseum method. Single-drug oxaliplatin was dosed at 350–460 mg/m2, and oxaliplatin and irinotecan combined at 360 mg/m2 for both drugs. These treatments lasted for 30 min. Mitomycin C was dosed at 35 mg/m2 divided into three injections with 50 per cent given at time 0, 25 per cent at 30 min, and 25 per cent at 60 min from the start of HIPEC for a total of 90 min. Follow-up data on PRFS and OS were collected for the final analysis. The Uppsala University ethical committee approved the study (Dnr 2007/237 for tumour sampling and ex vivo assessment of drug activity, and Dnr 2013/203 for clinical data collection).

Scanning Electron Microscope Examination as an Alternative to Classical Microbiology in the Diagnostics of Catheter-Related Sepsis?

Central venous catheters are essential elements enabling the treatment of intensive care unit patients. However, these catheters are sometimes colonised by both bacteria and fungi, and thus, they may become a potential source of systemic infections-catheter-related bloodstream infections (CRBSI). The identification of the pathogen responsible for CRBSI is a time-consuming process. At the same time, the relationship between the quick identification of the pathogen and the implementation of targeted antibiotic therapy is of key importance for controlling the clinical symptoms of sepsis and septic shock in the patient. Quick diagnosis is of key importance to reduce morbidity and mortality in this group of patients. In our study, we attempted to create a catalogue of images of the most commonly cultured pathogens responsible for CRBSI. An FEI Quanta 250 FEG Scanning Electron Microscope (SEM) was used for measurements. SEM images obtained during the analysis were included in this study. Images of SEM are three-dimensional and comparable to the images seen with the human eye and are a tool used for research and measurement whenever it is necessary to analyse the state of the surface and assess its morphology. The method described in our study will not replace the current procedures recognised as the gold standard, i.e., pathogen culturing, determination of the count of microorganisms (CFU -colony forming units), and assessment of drug sensitivity. However, in some cases, the solution proposed in our study may aid the diagnosis of patients with suspected catheter-related bloodstream infections leading to sepsis and septic shock.

Breast cancer patient-derived explant cultures recapitulate in vivo drug responses.

Assessment of drug sensitivity in tumor tissue ex vivo may significantly contribute to functional diagnostics to guide personalized treatment of cancer. Tumor organoid- and explant-cultures have become attractive tools towards this goal, although culturing conditions for breast cancer (BC) tissue have been among the most challenging to develop. Validation of possibilities to detect concordant responses in individual tumors and their respective cultures ex vivo is still needed. Here we employed BC patient-derived xenografts (PDXs) with distinct drug sensitivity, to evaluate different conditions for tissue dissociation, culturing and monitoring of treatment efficacy ex vivo, aiming to recapitulate the in vivo drug responses. The common challenge of discriminating between tumor and normal cells in the cultured tissue was also addressed. Following conventional enzymatic dissociation of BC tissue, the tumor cells stayed within the non-disrupted tissue fragments, while the single cells represented mostly normal host cells. By culturing such fragments as explants, viable tumor tissue could be maintained and treated ex vivo, providing representative indications on efficacy of the tested treatment. Thus, drug sensitivity profiles, including acquired chemoresistance seen in the PDXs, were recapitulated in the respective explants. To detect the concordant responses, however, the effect monitoring had to be harmonized with the characteristics of the cultured tissue. In conclusion, we present the feasibility of BC explants ex vivo to capture differences in drug sensitivity of individual tumors. The established protocols will aid in setting up an analogous platform for BC patient biopsies with the aim to facilitate functional precision medicine.

Cell senescence-associated genes predict the malignant characteristics of glioblastoma

BackgroundGlioblastoma (GBM) is the most malignant, aggressive and recurrent primary brain tumor. Cell senescence can cause irreversible cessation of cell division in normally proliferating cells. According to studies, senescence is a primary anti-tumor mechanism that may be seen in a variety of tumor types. It halts the growth and spread of tumors. Tumor suppressive functions held by cellular senescence provide new directions and pathways to promote cancer therapy.MethodsWe comprehensively analyzed the cell senescence-associated genes expression patterns. The potential molecular subtypes were acquired based on unsupervised cluster analysis. The tumor immune microenvironment (TME) variations, immune cell infiltration, and stemness index between 3 subtypes were analyzed. To identify genes linked with GBM prognosis and build a risk score model, we used weighted gene co-expression network analysis (WGCNA), univariate Cox regression, Least absolute shrinkage and selection operator regression (LASSO), and multivariate Cox regression analysis. And the correlation between risk scores and clinical traits, TME, GBM subtypes, as well as immunotherapy responses were estimated. Immunohistochemistry (IHC) and cellular experiments were performed to evaluate the expression and function of representative genes. Then the 2 risk scoring models were constructed based on the same method of calculation whose samples were acquired from the CGGA dataset and TCGA datasets to verify the rationality and the reliability of the risk scoring model. Finally, we conducted a pan-cancer analysis of the risk score, assessed drug sensitivity based on risk scores, and analyzed the pathways of sensitive drug action.ResultsThe 3 potential molecular subtypes were acquired based on cell senescence-associated genes expression. The Log-rank test showed the difference in GBM patient survival between 3 potential molecular subtypes (P = 0.0027). Then, 11 cell senescence-associated genes were obtained to construct a risk-scoring model, which was systematically randomized to distinguish the train set (n = 293) and the test set (n = 292). The Kaplan-Meier (K-M) analyses indicated that the high-risk score in the train set (P < 0.0001), as well as the test set (P = 0.0053), corresponded with poorer survival. In addition, the high-risk score group showed a poor response to immunotherapy. The reliability and credibility of the risk scoring model were confirmed according to the CGGA dataset, TCGA datasets, and Pan-cancer analysis. According to drug sensitivity analysis, it was discovered that LJI308, a potent selective inhibitor of RSK pathways, has the highest drug sensitivity. Moreover, the GBM patients with higher risk scores may potentially be more beneficial from drugs that target cell cycle, mitosis, microtubule, DNA replication and apoptosis regulation signaling.ConclusionWe identified potential associations between clinical characteristics, TME, stemness, subtypes, and immunotherapy, and we clarified the therapeutic usefulness of cell senescence-associated genes.

A cancer-associated fibroblast gene signature predicts prognosis and therapy response in patients with pancreatic cancer.

Pancreatic cancer is a lethal malignancy with a 5-year survival rate of about 10% in the United States, and it is becoming an increasingly prominent cause of cancer death. Among pancreatic cancer patients, pancreatic ductal adenocarcinoma (PDAC) accounts for more than 90% of all cases and has a very poor prognosis with an average survival of only 1 year in about 18% of all tumor stages. In the past years, there has been an increasing interest in cancer-associated fibroblasts (CAFs) and their roles in PDAC. Recent data reveals that CAFs in PDAC are heterogeneous and various CAF subtypes have been demonstrated to promote tumor development while others hinder cancer proliferation. Furthermore, CAFs and other stromal populations can be potentially used as novel prognostic markers in cancer. In the present study, in order to evaluate the prognostic value of CAFs in PDAC, CAF infiltration rate was evaluated in 4 PDAC datasets of TCGA, GEO, and ArrayExpress databases and differentially expressed genes (DEGs) between CAF-high and CAF-low patients were identified. Subsequently, a CAF-based gene expression signature was developed and studied for its association with overall survival (OS). Additionally, functional enrichment analysis, somatic alteration analysis, and prognostic risk model construction was conducted on the identified DEGs. Finally, oncoPredict algorithm was implemented to assess drug sensitivity prediction between high- and low-risk cohorts. Our results revealed that CAF risk-high patients have a worse survival rate and increased CAF infiltration is a poor prognostic indicator in pancreatic cancer. Functional enrichment analysis also revealed that "extracellular matrix organization" and "vasculature development" were the top enriched pathways among the identified DEGs. We also developed a panel of 12 genes, which in additional to its prognostic value, could predict higher chemotherapy resistance rate. This CAF-based panel can be potentially utilized alone or in conjunction with other clinical parameters to make early predictions and prognosticate responsiveness to treatment in PDAC patients. Indeed, it is necessary to conduct extensive prospective investigations to confirm the clinical utility of these findings.

An off-the-shelf multi-well scaffold-supported platform for tumour organoid-based tissues

Complex 3D bioengineered tumour models provide the opportunity to better capture the heterogeneity of patient tumours. Patient-derived organoids are emerging as a useful tool to study tumour heterogeneity and variation in patient responses. Organoid cultures typically require a 3D microenvironment that can be manufactured easily to facilitate screening. Here we set out to create a high-throughput, “off-the-shelf” platform which permits the generation of organoid-containing engineered microtissues for standard phenotypic bioassays and image-based readings. To achieve this, we developed the Scaffold-supported Platform for Organoid-based Tissues (SPOT) platform. SPOT is a 3D gel-embedded in vitro platform that can be produced in a 96- or 384-well plate format and enables the generation of flat, thin, and dimensionally-defined microgels. SPOT has high potential for adoption due to its reproducible manufacturing methodology, compatibility with existing instrumentation, and reduced within-sample and between-sample variation, which can pose challenges to both data analysis and interpretation. Using SPOT, we generate cultures from patient derived pancreatic ductal adenocarcinoma organoids and assess the cellular response to standard-of-care chemotherapeutic compounds, demonstrating our platform's usability for drug screening. We envision 96/384-SPOT will provide a useful tool to assess drug sensitivity of patient-derived organoids and easily integrate into the drug discovery pipeline.

Establishment and Genetic Profiling of Platinum/Taxane Doublet-Resistant Cells Generated by Hybridizing Single Resistant Cells

Background: Current standard chemotherapy for gynecologic malignancies consists of platinum agent and taxane though, many patients experience the relapse of disease with drug resistance making the following therapy unsuccessful. It’s a compelling question whether the mechanisms of doubly resistance is a simple combination of single agent resistance or whether the core novel mechanism common to platinum and taxane resistance stands out as a result of combination therapy. The purpose of this study is to establish the doublet drug resistant cell line and to find its genetic characteristics. Methods: Platinum/taxane doublet resistant cell lines (F3 and F4) were generated by hybridizing two independent, platinum or taxane resistant subline (C13 or PX24) stemmed from grand parental ME180 cells. The resistant cells were selected through repeated exposure to cisplatin and paclitaxel. For the assessment of drug sensitivity, colony forming assay was used. For the gene expression analysis, genome-wide expression profiling was done using the Human Genome U133A Array. Protein-protein interaction network (PPI) scaffold networks were retrieved from the Search Tool for the Retrieval of Interacting Genes database and, for the enrichment of pathway analysis, WebGestalt was used. Results: Colony forming assay showed C13 was 5.8-fold cisplatin resistant while PX24 was 5.3-fold paclitaxel resistant compared with parental ME180 cells. F3 and F4 acquired resistance to cisplatin and paclitaxel by 8.3/4.9- and 3.7/3.3-fold (F3/4) respectively. Microarray analysis demonstrated, out of 22284 genes, 103 genes were &gt;4-fold up-regulated in F3/4 and 33 (32%) were identified as simultaneously upregulated genes (SUG) in C13, PX24 and F3/4. The Protein-protein interaction analysis of 33 SUG displayed a scaffold network pivoting aldo-keto reductase 1C1 (AKR1C1), aldo-keto reductase1C2 (AKR1C2) and aldo-keto reductase1C3 (AKR1C3). The enrichment pathway analysis demonstrated AKR1C gene family anchored to molecular function of oxidoreductase and aldo-keto reductase activity and biological process of daunorubicin and doxorubicin metabolism. Conclusions: We report here the establishment of doubly drug-resistant hybridoma to platinum and taxane. Analysis of SUG indicated the AKR1C gene family plays a key role for doubly resistant mechanism that would be possible targets for therapeutic strategies.

Individualized therapy based on the combination of mini-PDX and NGS for a patient with metastatic AFP-producing and HER-2 amplified gastric cancer.

Mini-patient-derived xenograft (mini-PDX) is a novel, rapid and accurate method used to assess in vivo drug susceptibility. In the present study, a mini-PDX combined with next-generation sequencing (NGS) was used to guide the individualized treatment of a patient with metastatic a-fetoprotein-producing and human epidermal growth factor receptor 2 (HER-2) amplified gastric cancer (GC). Tumor cells were isolated from the tumor tissue obtained from gastroscopic biopsy, transferred into capsules and implanted into severe combined immunodeficiency mice to determine their sensitivity to various drug regimens. NGS was also performed to assess the mutation spectrum of the cells. The results were analyzed to select the most appropriate treatment regimen for the patient. The mini-PDX model confirmed that the patient's tumor was sensitive to a combination regimen of irinotecan and tegafur-gimeracil-oteracil (S-1). Fluorescence in situ hybridization assay of the tumor tissue confirmed HER-2 amplification. The NGS results indicated ERBB2 amplification, and tumor protein P53 [c.659A>G (p.Y220C)], ataxia-telengiectasia mutated [c.125A>G (p.H42R)] and MutS homolog 6 [c.3254C(8>7) (p.F1088Sfs*2)] mutation, in which UGT1A1*28, TA6/7 (rs8175347) was a mutant heterozygote. After six courses of treatment with a regimen comprising 300 mg irinotecan on day 1 + 40 mg S-1 twice daily on days 2–15 + 350 mg trastuzumab once-every 3 weeks, the patient continued with S-1 treatment for 4 courses and trastuzumab for 1 year. The patient retained progression-free survival status at the 32-month follow-up. Thus, the mini-PDX model combined with the NGS rapidly assessed drug sensitivity in a patient with GC and revealed key genetic mutations. However, the proposed technique requires further research to confirm its potential in the individualized treatment of patients with refractory malignancies.

Proteomic and phosphoproteomic measurements enhance ability to predict ex vivo drug response in AML

Acute Myeloid Leukemia (AML) affects 20,000 patients in the US annually with a five-year survival rate of approximately 25%. One reason for the low survival rate is the high prevalence of clonal evolution that gives rise to heterogeneous sub-populations of leukemic cells with diverse mutation spectra, which eventually leads to disease relapse. This genetic heterogeneity drives the activation of complex signaling pathways that is reflected at the protein level. This diversity makes it difficult to treat AML with targeted therapy, requiring custom patient treatment protocols tailored to each individual’s leukemia. Toward this end, the Beat AML research program prospectively collected genomic and transcriptomic data from over 1000 AML patients and carried out ex vivo drug sensitivity assays to identify genomic signatures that could predict patient-specific drug responses. However, there are inherent weaknesses in using only genetic and transcriptomic measurements as surrogates of drug response, particularly the absence of direct information about phosphorylation-mediated signal transduction. As a member of the Clinical Proteomic Tumor Analysis Consortium, we have extended the molecular characterization of this cohort by collecting proteomic and phosphoproteomic measurements from a subset of these patient samples (38 in total) to evaluate the hypothesis that proteomic signatures can improve the ability to predict response to 26 drugs in AML ex vivo samples. In this work we describe our systematic, multi-omic approach to evaluate proteomic signatures of drug response and compare protein levels to other markers of drug response such as mutational patterns. We explore the nuances of this approach using two drugs that target key pathways activated in AML: quizartinib (FLT3) and trametinib (Ras/MEK), and show how patient-derived signatures can be interpreted biologically and validated in cell lines. In conclusion, this pilot study demonstrates strong promise for proteomics-based patient stratification to assess drug sensitivity in AML.

Overexpression of satellite RNAs in heterochromatin induces chromosomal instability and reflects drug sensitivity in mouse cancer cells

Overexpression of satellite RNAs in heterochromatin induces chromosomal instability (CIN) through the DNA damage response and cell cycle checkpoint activation. Although satellite RNAs may be therapeutic targets, the associated mechanisms underlying drug sensitivity are unknown. Here, we determined whether satellite RNAs reflect drug sensitivity to the topoisomerase I inhibitor camptothecin (CPT) via CIN induction. We constructed retroviral vectors expressing major satellite and control viruses, infected microsatellite stable mouse colon cancer cells (CT26) and MC38 cells harboring microsatellite instability, and assessed drug sensitivity after 48 h. Cells overexpressing satellite RNAs showed clear features of abnormal segregation, including micronuclei and anaphase bridging, and elevated levels of the DNA damage marker γH2AX relative to controls. Additionally, overexpression of satellite RNAs enhanced MC38 cell susceptibility to CPT [half-maximal inhibitory concentration: 0.814 μM (control) vs. 0.332 μM (MC38 cells with a major satellite), p = 0.003] but not that of CT26. These findings imply that MC38 cells, which are unlikely to harbor CIN, are more susceptible to CIN-induced CPT sensitivity than CT26 cells, which are characterized by CIN. Furthermore, CPT administration upregulated p53 levels but not those of p21, indicating that overexpression of major satellite transcripts likely induces CPT-responsive cell death rather than cellular senescence.

MODL-27. An organotypic brain slice culture platform as a novel pre-clinical model for diffuse intrinsic pontine glioma and diffuse midline glioma

High-grade pediatric brain tumors (PBTs) such as diffuse intrinsic pontine glioma (DIPG) and diffuse midline glioma (DMG) are devastating diseases with a median survival of just 11 months. Little progress has been made in identifying effective treatments due to the lack of effective pre-clinical models to accurately assess drug sensitivity. Historically, models of DIPG and DMG have been limited due to the low availability of surgical biopsies and small patient populations. Existing in vitro models are often unable to recapitulate growth and migration patterns seen in patients, while in vivo work is costly, time intensive, and many biopsies fail to establish in mice. We have developed an ex vivo organotypic brain slice culture (OBSC) platform to model DIPG and DMG. Through our partnership with the Ian’s Friends Foundation and Children’s Healthcare of Atlanta Biobank, we have seeded, grown, and treated several low-passage patient-derived PBT lines such as DIPG and DMG. Additionally, we can assess treatment response to a variety of agents used in clinical patient care. Viability assays revealed differences in the sensitivity of cell lines to individual agents, indicating that OBSCs have the potential to capture minute differences in efficacy between cell lines and drugs. When we assessed combination treatments, we found low doses of radiation with low doses of temozolomide were synergistic, but using higher doses of radiation was antagonistic, suggesting the OBSC platform has the potential to guide dosing strategies to maximize therapeutic synergy. Overall, these results suggest that OBSC PBT models have the potential to effectively model PBTs, including DIPG and DMG, to accelerate preclinical evaluation of therapeutics and guide drug development towards more effective treatment strategies.

P-79 Precision oncology without biomarkers: Assessing drug sensitivity in patient-derived tumoroids to guide mCRC 3rd line therapy

“Precision Oncology” refers to strategies and tools to find the best treatment for a specific patient. This concept is often reduced to the combination of targeted therapies with molecular biomarkers. Nevertheless, most options indicated in guidelines for 3rd line treatment of mCRC patients do not have associated biomarkers. In vitro assessment of tumor drug sensitivity based on patient-derived 3D tumoroids can be used to guide therapy decision-making. Furthermore, it can inform the “off label” use of drugs susceptible of improving patient’s PFS.

Approaches to identifying drug resistance mechanisms to clinically relevant treatments in childhood rhabdomyosarcoma.

Aim: Despite aggressive multiagent protocols, patients with metastatic rhabdomyosarcoma (RMS) have poor prognosis. In a recent high-risk trial (ARST0431), 25% of patients failed within the first year, while on therapy and 80% had tumor progression within 24 months. However, the mechanisms for tumor resistance are essentially unknown. Here we explore the use of preclinical models to develop resistance to complex chemotherapy regimens used in ARST0431. Methods: A Single Mouse Testing (SMT) protocol was used to evaluate the sensitivity of 34 RMS xenograft models to one cycle of vincristine, actinomycin D, cyclophosphamide (VAC) treatment. Tumor response was determined by caliper measurement, and tumor regression and event-free survival (EFS) were used as endpoints for evaluation. Treated tumors at regrowth were transplanted into recipient mice, and the treatment was repeated until tumors progressed during the treatment period (i.e., became resistant). At transplant, tumor tissue was stored for biochemical and omics analysis. Results: The sensitivity to VAC of 34 RMS models was determined. EFS varied from 3 weeks to > 20 weeks. Tumor models were classified as having intrinsic resistance, intermediate sensitivity, or high sensitivity to VAC therapy. Resistance to VAC was developed in multiple models after 2-5 cycles of therapy; however, there were examples where sensitivity remained unchanged after 3 cycles of treatment. Conclusion: The SMT approach allows for in vivo assessment of drug sensitivity and development of drug resistance in a large number of RMS models. As such, it provides a platform for assessing in vivo drug resistance mechanisms at a “population” level, simulating conditions in vivo that lead to clinical resistance. These VAC-resistant models represent “high-risk” tumors that mimic a preclinical phase 2 population and will be valuable for identifying novel agents active against VAC-resistant disease.

Assessment of Drug Sensitivity of Different Urinary Isolates to Nitrofurantoin and its Comparison with Other DrugsA Retrospective Study

Introduction: Uncomplicated Urinary Tract Infection (UTI) is one of the most common indications for antibiotic use in the community. However, gram negative organisms that are predominant cause of UTI are becoming increasingly resistant to commonly used antibiotics. Consequently, empiric therapy is likely to fail resulting in increasing number of patients with uncomplicated UTI requiring hospitalisation for intravenous antibiotics as there are no oral treatment options left. Aim: To assess the susceptibility trends of urinary isolates to panel of antibiotics with particular reference to nitrofurantoin. Materials and Methods: The present study was a retrospective study conducted at Adesh Hospital Bathinda, Punjab, India for a period of one year from April 2020-April 2021. Kass criteria was followed for interpretation of significant bacteriuria according to which significant growth is considered if number of colony is more than 105 Colony Forming Unit (CFU)/mL. Culture positive were analysed by Gram staining and on the basis of colony characteristics, gram staining, final identification was done using Vitek 2 compact system. Statistical analysis was done using Chi-square test. Results: A total of 392 urinary isolates were identified during the study period. Out of the 392 isolates 316 (80.6%) were gram negative isolates and 76 (19.4%) were gram positive isolates. Maximum sensitivity was shown to nitrofurantoin, 88% in case of gram negative isolates and 76% in case of gram positive isolates. Conclusion: Nitrofurantoin is an effective therapeutic agent in the treatment of UTI. It has been used for a long time, but the emergence of antibiotic resistance and the decline in newly developed antibiotics has increased interest in the treatment of bacterial UTI with this antibiotic

Circulating Tumor Cell Lines: an Innovative Tool for Fundamental and Translational Research.

Metastasis is a leading cause of cancer death. Despite improvements in treatment strategies, metastatic cancer has a poor prognosis. We thus face an urgent need to understand the mechanisms behind metastasis development, and thus to propose efficient treatments for advanced cancer. Metastatic cancers are hard to treat, as biopsies are invasive and inaccessible. Recently, there has been considerable interest in liquid biopsies including both cell-free circulating deoxyribonucleic acid (DNA) and circulating tumor cells from peripheral blood and we have established several circulating tumor cell lines from metastatic colorectal cancer patients to participate in their characterization. Indeed, to functionally characterize these rare and poorly described cells, the crucial step is to expand them. Once established, circulating tumor cell (CTC) lines can then be cultured in suspension or adherent conditions. At the molecular level, CTC lines can be further used to assess the expression of specific markers of interest (such as differentiation, epithelial or cancer stem cells) by immunofluorescence or cytometry analysis. In addition, CTC lines can be used to assess drug sensitivity to gold-standard chemotherapies as well as to targeted therapies. The ability of CTC lines to initiate tumors can also be tested by subcutaneous injection of CTCs in immunodeficient mice. Finally, it is possible to test the role of specific genes of interest that might be involved in cancer dissemination by editing CTC genes, by short hairpin ribonucleic acid (shRNA) or Crispr/Cas9. Modified CTCs can thus be injected into immunodeficient mouse spleens, to experimentally mimic part of the metastatic development process in vivo. In conclusion, CTC lines are a precious tool for future research and for personalized medicine, where they will allow prediction of treatment efficiency using the very cells that are originally responsible for metastasis.

ET-8 Integrated diagnostic approach to predict prognosis for malignant gliomas

Previous studies indicated that MGMT promoter methylation status with IDH and TERT promotor mutation are major prognostic factors in glioma. In addition to these molecular features, we have been assessing drug sensitivity against several chemotherapeutic agents, including temozolomide (TMZ). Here, we examined if this combined information could strongly predict drug sensitivity and the prognosis in glioma patients. One hundred and twenty-five IDH wild-type gliomas (WHO grade III and grade IV) were included in this study and retrospectively analyzed. Among them, we focused on 37 patients with partial surgical resection and biopsy to assess radiological difference on MRI. The primary cultured tumor cells were exposed with several compounds for 72 hours, then ATP based cell viability assay was performed. The favorable radiological therapeutic effect was found in 6 out of 8 (75%) with MGMT promoter methylated cases, while unfavorable in 23 of 29 (79.3%) with MGMT promoter unmethylated cases (p=0.008). The drug screening assay demonstrated that 7 of 10 cases with favorable TMZ sensitivity in vitro showed response on MRI, whereas 22 of 27 (81.5%) cases with TMZ resistance in vitro indicated tumor progression (p=0.006). Of note, all 5 cases with sensitive to TMZ and methylated MGMT promoter demonstrated favorable radiological response (p=0.002). These 5 cases tended to survive longer (median survival time, 697 days) as compared to others (median survival time, 391 days, p=0.13). These data indicate that integrated approach with genomic assessment and drug screening test may predict therapeutic response to chemotherapy and contribute selecting optimal therapy in glioma patients.

ET-1 Translational research platform for malignant brain tumors

Introduction: The standard therapy for malignant brain tumors includes surgery and combination therapy with radiation and chemotherapy, but to provide individualized treatment based on the biological and molecular genetic background of the tumor, integrate genetic information with various functional data are required. In this study, we present an overview of our integrated approaches for translational research and clinical management. Methods: In glioma, pre-and intra-operative clinical information, including intraoperative genetic diagnosis, and intraoperative rapid immunohistochemistry is obtained, then a multidisciplinary treatment approach is started based on these integrated data. Specimens collected intraoperatively are cryopreserved for future analysis, and primary cultured cells are routinely collected. The cultured cells are transplanted into the brain of immunodeficient mice to establish patient-derived xenograft model (PDX). Genetic screening, such as IDH, TERT, BRAF, H3F3A mutation and MGMT methylation analysis are routinely assessed within a few days after surgery and used as information for integrated diagnosis. In case of PDX establishment or recurrence, we perform whole exon sequencing or comprehensive genomic assessment to identify genetic abnormalities. If genomic alterations for possible molecular targeted therapy are identified, we assess drug sensitivity test in vitro and in vivo, which are utilized for research to develop optimal molecular targeted therapy. The results, such as the therapeutic effects of molecular targeted drugs, are used for clinical applications. Results: Since the platform was established, we have treated a total of 286 patients, including 189 gliomas and 37 central nervous system lymphomas based on the integrated information. We are currently collecting clinical data to examine if this integrated approach could provide clinical benefit.Conclusion: The translational research system for malignant brain tumors plays an important role in the promotion of clinical and basic research.

Abstract 1061: Characterization of synergistic selinexor combinations with dexamethasone, pomalidomide, elotuzumab, and daratumumab in primary MM cells

Abstract Introduction. Multiple myeloma (MM) is an all but incurable plasma cell malignancy without predictive biomarkers for approved therapies. Selinexor (SELI), a nuclear export inhibitor targeting exportin 1 (XPO1), is approved with dexamethasone (DEX) with promising SELI-combination studies ongoing. We investigated SELI combinations ex vivo to identify synergistic combinations and companion biomarkers. Methods. We established a platform to perform parallel RNA/exome sequencing and ex vivo drug sensitivity assessment on CD138+ cells from MM patient bone marrow aspirates. At the time of this analysis, 844 different samples with clinical, WES and RNA sequencing data were treated ex vivo with the following agents: SELI (n=75), DEX (192), pomalidomide (POM, 268), elotuzumab (ELO, 21), daratumumab (DARA, 117), SELI+DEX (22), SELI+POM (20), SELI+ELO (21), SELI+DARA (27). Cells were cultured with autologous macrophages, stroma, collagen matrix and patient-derived serum. Cell death (LD50 and AUC) was assessed through digital image analysis. Sequencing was performed through ORIEN/AVATAR. Links between non-synonymous mutations in coding genes and cell death were calculated using T-tests with multiple test correction. Results. Our analysis identified SELI+DEX (number of samples=60, p&amp;lt;1E-9), SELI+POM (57, p&amp;lt;0.001) and SELI+ELO (55, p&amp;lt;0.01) as the most synergistic combinations (BLISS model). SELI+DARA showed synergy in 23 out of 50 samples tested. Notably, both direct drug toxicity and phagocytosis were observed. RNAseq found gene expression associations with drug resistance/response. In turn, gene set enrichment analysis (GSEA) showed that SELI resistance was associated with expression of cell adhesion, inflammatory cytokines, and EMT pathways, while the MYC targets were associated with SELI sensitivity. SELI+ELO resistance was associated with expression of hedgehog signaling pathway, while expression of ribosomal subunits was associated with sensitivity. SELI+POM resistance was linked with lysosome and cell adhesion molecules, while sensitivity was tied to ribosome, spliceosome and RNA polymerase. GSEA also identified G2M, MTORC1, MYC targets, E2F and glycolysis as biomarkers for the SELI+DARA synergistic subgroup. WES also identified mutations associated with SELI sensitivity. Mutation of BCL7A, a protein involved in chromatin remodeling, was associated with sensitivity, and mutation of CEP290, which encodes a microtubule binding protein, was associated with resistance (p&amp;lt;0.05). Both BCL7A and CEP290 contain predicted nuclear export sequences, suggesting they are XPO1 cargoes. Conclusions. We observed ex vivo synergy between SELI and DEX, POM, ELO and DARA, and identified expression signatures and mutations associated with response to these agents. Ongoing analysis of additional samples is being performed to validate these results. Citation Format: Praneeth Reddy Sudalagunta, Mark B. Meads, Rafael Renatino Canevarolo, Maria Coelho Silva, Christopher Cubitt, Gabriel DeAvila, Raghunandan Reddy Alugubelli, Constantine N. Logothetis, Amit Kulkarni, Qi Zhang, Oliver Hampton, Christopher J. Walker, Yosef Landesman, Kenneth Shain, Ariosto Siqueira Silva. Characterization of synergistic selinexor combinations with dexamethasone, pomalidomide, elotuzumab, and daratumumab in primary MM cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1061.

Apoptotic Bodies in the Pancreatic Tumor Cell Culture Media Enable Label-Free Drug Sensitivity Assessment by Impedance Cytometry.

The ability to rapidly and sensitively predict drug response and toxicity using in vitro models of patient-derived tumors is essential for assessing chemotherapy efficacy. Currently, drug sensitivity assessment for solid tumors relies on imaging adherent cells or by flow cytometry of cells lifted from drug-treated cultures after fluorescent staining for apoptotic markers. Subcellular apoptotic bodies (ABs), including microvesicles that are secreted into the culture media under drug treatment can potentially serve as markers for drug sensitivity, without the need to lift cells under culture. However, their stratification to quantify cell disassembly is challenging due to their compositional diversity, with tailored labeling strategies currently needed for the recognition and cytometry of each AB type. It is shown that the high frequency impedance phase versus size distribution of ABs determined by high-throughput single-particle impedance cytometry of supernatants in the media of gemcitabine-treated pancreatic tumor cultures exhibits phenotypic resemblance to lifted apoptotic cells and enables shape-based stratification within distinct size ranges, which is not possible by flow cytometry. It is envisioned that this tool can be applied in conjunction with the appropriate pancreatic tumor microenvironment model to assess drug sensitivity and toxicity of patient-derived tumors, without the need to lift cells from cultures.

Decrease of ABCB1 protein expression and increase of G1 phase arrest induced by oleanolic acid in human multidrug-resistant cancer cells.

Oleanolic acid (OA) is a natural compound that can be found in a number of edible and medicinal plants and confers diverse biological actions. However, the direct target of OA in human tumor cells remains poorly understood, preventing its application in clinical and health settings. A previous study revealed that overexpression of caveolin-1 in human leukemia HL-60 cells can increase its sensitivity to OA. The present study aimed to investigate the effects of OA on the doxorubicin-resistant human breast cancer MCF-7 cell line (MCF-7/DOX), harringtonine-resistant human leukemia HL-60 cells (HL-60/HAR) and their corresponding parental cell lines. Western blotting was performed to measure protein expression levels, whilst Cell Counting Kit-8 (CCK-8) assays, cell cycle analysis (by flow cytometry) and apoptosis assays (with Annexin V/PI staining) were used to assess drug sensitivity. CCK-8 assay results suggested that MCF-7/DOX cells, which overexpress the caveolin-1 protein, have similar OA susceptibility to their parent line. In addition, sensitivity of MCF-7/DOX cells to OA was not augmented by knocking down caveolin-1 using RNA interference. HL-60/HAR cells exhibited a four-fold increased sensitivity to OA compared with that in their parental HL-60 cells according to CCK-8 assay. Both of the resistant cell lines exhibited higher numbers of cells at G1 phase arrest compared with those in their parent lines, as measured via flow cytometry. Treatment of both MCF-7 cell lines with 100 µM OA for 48 h induced apoptosis, with increased effects observed in resistant cells. However, no PARP-1 or caspase-3 cleavage was observed, with some positive Annexin V staining found after HL-60/HAR cells were treated with OA, suggesting that cell death occurred via non-classical apoptosis or through other cell death pathways. It was found that OA was not a substrate of ATP-binding cassette subfamily B member 1 (ABCB1) in drug-resistant cells, as indicated by the accumulation of rhodamine 123 assessed using flow cytometry. However, protein expression of ABCB1 in both of the resistant cell lines was significantly decreased after treatment with OA in a concentration-dependent manner. Collectively, these results suggest that OA could reduce ABCB1 protein expression and induce G1 phase arrest in multidrug-resistant cancer cells. These findings highlight the potential of OA for cancer therapy.