Patient-Derived Organoids for In Vivo Validation of In Vitro Data

Patient-derived organoids are promising tumor models for functional validation of next-generation sequencing-based therapy recommendations. In times of rapidly advancing precision oncology approaches in everyday clinical processes, reliable and valid tumor models are required. Tumor organoids consist of tumor "stem" cells, differentiated (epithelial) tumor, and stroma cells. The cellular architecture and interactions closely mimic the original patient tumor. These organoids can be implanted into immunodeficient mice, generating patient-derived organoid-derived xenografts, thus enabling in vitro to in vivo transfer. Most importantly, the high clinical relevance of PDO models is maintained in this conversion. This protocol describes in detail the methods and techniques as well as the materials necessary to generate in vitro PDO and in vivo PDO-derived xenograft models. The elaborate process description starts with the processing of freshly obtained tumor tissue. The proceedings include tissue processing, organoid culturing, PDO implantation into immunodeficient mice, tumor explantation, and finally tumor preservation. All these proceedings are described in this timely chronological order. This protocol will enable researchers to generate PDO models from freshly received tumor tissue and generate PDO-derived xenografts. Models generated according to these methods are suitable for a very broad research spectrum.

Establishment and Characterization of Novel Human Intestinal In Vitro Models for Absorption and First-Pass Metabolism Studies

Commonly used intestinal in vitro models are limited in their potential to predict oral drug absorption. They either lack the capability to form a tight cellular monolayer mimicking the intestinal epithelial barrier or the expression of cytochrome P450 3A4 (CYP3A4). The aim of this study was to establish a platform of colorectal cancer patient-derived cell lines for evaluation of human intestinal drug absorption and metabolism. We characterized ten 2D cell lines out of our collection with confluent outgrowth and long-lasting barrier forming potential as well as suitability for high throughput applications with special emphasis on expression and inducibility of CYP3A4. By assessment of the transepithelial electrical resistance (TEER) the cells barrier function capacity can be quantified. Very high TEER levels were detected for HROC60. A high basal CYP3A4 expression and function was found for HROC32. Eight cell lines showed higher CYP3A4 induction by stimulation via the vitamin D receptor compared to Caco-2 cells (5.1- to 16.8-fold change). Stimulation of the pregnane X receptor led to higher CYP3A4 induction in two cell lines. In sum, we identified the two cell lines HROC183 T0 M2 and HROC217 T1 M2 as useful tools for in vitro drug absorption studies. Due to their high TEER values and inducibility by drug receptor ligands, they may be superior to Caco-2 cells to analyze oral drug absorption and intestinal drug–drug interactions. Significance statement: Selecting appropriate candidates is important in preclinical drug development. Therefore, cell models to predict absorption from the human intestine are of the utmost importance. This study revealed that the human cell lines HROC183 T0 M2 and HROC217 T1 M2 may be better suited models and possess higher predictive power of pregnane X receptor- and vitamin D-mediated drug metabolism than Caco-2 cells. Consequently, they represent useful tools for predicting intestinal absorption and simultaneously enable assessment of membrane permeability and first-pass metabolism.

Global Association of Cause-specific Mortality between the Major Gastrointestinal Cancers and Parkinson's Disease for the First Two Decades of the New Millennium

Parkinson's disease (PD) and gastrointestinal (GI) cancers are both "age-related diseases" sharing several environmental risk factors, but possess opposite underlying biological mechanisms. Aim of this study was to evaluate the correlations between GI cancers and PD using national cause-specific mortality data of 183 countries extracted from the Global Health Observatory database. The association between PD- and GI cancers- (i.e. esophagus cancer, EC; stomach cancer, SC; colorectal cancer, CRC; liver cancer, LC and pancreatic cancer, PC) specific mortality on the country level was evaluated using Spearman correlation and logistic regression analysis. A global increase in mortality from 2000 to 2019 was observed in PD, CRC and PC, whereas in EC, SC and LC it decreased. We see the consistent diminishment of correlation intensities between PD and GI cancer mortalities from 2000 to 2019 as a positive development. In 2019, PD inversely correlated with CRC (r_s = -0.39) and PC (r_s = -0.40, all P < 0.001) but not with EC and SC. Of note, an exceptionally positive correlation of PD with LC (r_s = 0.26, P < 0.001) and its two hepatitis B and C virus-associated subtypes was revealed. Logistic regression analysis further determined that PD associated negatively with CRC (OR = 0.25) and PC (OR = 0.21, both P < 0.001), but positively with LC (OR = 2.27, P = 0.007). Consequently, future research aiming to unravel the functional biological link between neurodegeneration, hepatitis and tumor development holds great potential for developing novel therapeutics.

Glucose Influences the Response of Glioblastoma Cells to Temozolomide and Dexamethasone

Objective

Current research indicates that weakness of glucose metabolism plays an important role in silencing of invasiveness and growth of hypoxic tumors such as GBM. Moreover, there are indications that DXM, frequently used in treatment, may support GBM energy metabolism and provoke its recurrence.

Methods

We carried out in vitro experiments on the commercial T98G cell line and two primary GBM lines (HROG02, HROG17) treated with TMZ and/or DXM in physiological oxygen conditions for GBM (2.5% oxygen) and for comparison, in standard laboratory conditions (20% oxygen). The influence of different glucose levels on selected malignancy features of GBM cells-cellular viability and division, dynamic of cell culture changes, colony formation and concentration of InsR have been elevated.

Results

Under 2.5% oxygen and high glucose concentration, an attenuated cytotoxic effect of TMZ and intensification of malignancy features in all glioblastoma cell lines exposed to DXM was seen. Furthermore, preliminary retrospective analysis to assess the correlation between serum glucose levels and Ki-67 expression in surgical specimens derived from patients with GBM (IV) treated with radio-chemotherapy and prophylactic DXM therapy was performed.

Conclusion

The data suggest a link between the in vitro study results and clinical data. High glucose can influence on GBM progression through the promotion of the following parameters: cell viability, dispersal, InsR expression and cell proliferation (Ki-67). However, this problem needs more studies and explain the mechanism of action studied drugs.

Cancer-Cell-Derived IgG and Its Potential Role in Tumor Development

Human immunoglobulin G (IgG) is the primary component of the human serum antibody fraction, representing about 75% of the immunoglobulins and 10-20% of the total circulating plasma proteins. Generally, IgG sequences are highly conserved, yet the four subclasses, IgG1, IgG2, IgG3, and IgG4, differ in their physiological effector functions by binding to different IgG-Fc receptors (FcγR). Thus, despite a similarity of about 90% on the amino acid level, each subclass possesses a unique manner of antigen binding and immune complex formation. Triggering FcγR-expressing cells results in a wide range of responses, including phagocytosis, antibody-dependent cell-mediated cytotoxicity, and complement activation. Textbook knowledge implies that only B lymphocytes are capable of producing antibodies, which recognize specific antigenic structures derived from pathogens and infected endogenous or tumorigenic cells. Here, we review recent discoveries, including our own observations, about misplaced IgG expression in tumor cells. Various studies described the presence of IgG in tumor cells using immunohistology and established correlations between high antibody levels and promotion of cancer cell proliferation, invasion, and poor clinical prognosis for the respective tumor patients. Furthermore, blocking tumor-cell-derived IgG inhibited tumor cells. Tumor-cell-derived IgG might impede antigen-dependent cellular cytotoxicity by binding antigens while, at the same time, lacking the capacity for complement activation. These findings recommend tumor-cell-derived IgG as a potential therapeutic target. The observed uniqueness of Ig heavy chains expressed by tumor cells, using PCR with V(D)J rearrangement specific primers, suggests that this specific part of IgG may additionally play a role as a potential tumor marker and, thus, also qualify for the neoantigen category.

Epidemiologic trends and prognostic risk factors of patients with pancreatic neuroendocrine neoplasms in the US: an updated population-based study

Background: We aimed to evaluate the incidence, mortality and survival outcome for patients with pancreatic neuroendocrine neoplasms (pNEN). Methods: Patients with pNEN were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Incidence, mortality and average annual percentage change (AAPC) were calculated using SEER stat 8.3.6 and Joinpoint software. Survival outcome was estimated using Kaplan-Meier and Cox proportional hazard model. Results: During 2000-2016, the incidence of pNEN significantly rose from 0.2647 to 1.0618 per 100,000 persons with an AAPC of 9.4; AAPC of mortality was 6.7. Prognostic improvement was revealed in 2010-2016, but not for late-stage pNEN, which had the highest risk of death. Conclusion: Efforts to improve prognosis of pNEN patients must focus on not only early detection, but also on improving therapy for late-stage disease.

Development and Validation of a Score for Screening Suicide of Patients With Neuroendocrine Neoplasms

Background: If the diagnosis of neuroendocrine neoplasm (NEN) increases the risk of patients to commit suicide has not been investigated so far. Identifying NEN patients at risk to commit suicide is important to increase their life quality and life expectancy. Methods and findings: Cancer cases were extracted from the Surveillance, Epidemiology, and End Results program and were divided into the NEN and the non-NEN cohorts. Subsequently, the NEN patients were randomly split into a training data set and a validation data set. Analyzing the training data set, we developed a score for assessing the risk to commit suicide for patients with NEN. In addition, we validated the score using the validation data set and evaluated, if this score could also be applied to other cancer entities by using the test data set, a non-NEN cohort. The odds ratio (OR) of suicide between NEN and non-NEN patients was determined. Moreover, the performance of a score was evaluated by the receiver operating characteristic curve and the area under the curve (AUC). Compared to non-NEN, NEN significantly increased the risk of suicide to 1.8-fold (NEN vs. non-NEN; OR, 1.832; P < 0.001). In addition, we observed that age, gender, race, marital status, tumor stage, histologic grade, surgery, and chemotherapy were associated with suicide among NEN patients; and a synthesized score based on these factors could significantly distinguish suicide individuals from non-suicide individuals in the training data set (AUC, 0.829; P < 0.001) and in the validation data set (AUC, 0.735; P < 0.001). This score also had a good performance when it was assessed by the test data set (AUC, 0.690; P < 0.001). This demonstrates that the score might also be applicable to other cancer entities. Conclusions: This population-based study suggests that NEN patients have a higher risk of suicide than non-NEN patients. In addition, this study provided a score, which can identify NEN patients at high-risk of committing suicide. Thus, this score in combination with current screening and prevention strategies for suicide may improve life quality and life expectancy of NEN patients.

Analyzing non-cancer causes of death of colorectal carcinoma patients in the US population for the years 2000-2016

Background

Colorectal cancer (CRC) treatment and patient survival improved greatly. Consequently an increased incidence of non‐cancer‐related deaths is observed. This study analyzed the causes of non‐cancer death for people suffering from CRC based on the year of diagnosis, follow‐up time, and patient's age.

Methods

The data from patients diagnosed with CRC in the years 2000–2016 were taken from the Surveillance, Epidemiology, and End Results 18 database. Patients were categorized according to: death from CRC, non‐CRC cancer, and non‐cancer. Constituent ratios and standardized mortality ratios (SMRs) were calculated to describe the death causes distribution and relative death risks.

Results

Between 2000 and 2016, a stable and rapid drop for the original diagnosis as death cause for CRC patients was observed (70.19% to 49.35%). This was coupled to an increase in non‐cancer‐associated death reasons (23.38% to 40.00%). The most common non‐cancer death cause was heart disease, especially for elderly patients. However, deaths from accidents and adverse effects were frequent in younger CRC patients. Patients died from septicemia more often within the first follow‐up year; however, a 6‐fold increase in death from Alzheimer's disease was found for after at least 180 months follow‐up time.

The SMRs of all 25 non‐cancer death causes initially decreased in all CRC subgroups, followed by an increase with follow‐up times. Gradually decreasing SMR values were observed with increasing age of CRC patients.

Conclusions

These findings could help modify and sharpen preventive measures and clinical management and raise physician's awareness to potential non‐CRC death risk factors for CRC patients.

AMPA receptor antagonist perampanel affects glioblastoma cell growth and glutamate release in vitro

Epileptic seizures are frequent in patients with glioblastoma, and anticonvulsive treatment is often necessary. While clinical guidelines recommend all approved anticonvulsants, so far it is still unclear which of the available drugs is the best therapeutic option for treating glioma-associated seizures, also in view of possible anti-tumorigenic effects. In our study, we employed four patient-derived low-passage cell lines of glioblastoma and three cell lines of brain metastases, and challenged these cultures with four anticonvulsants with different mechanisms of action: levetiracetam, valproic acid, carbamazepine and perampanel. Cell proliferation was determined by bromodeoxyuridine incorporation. To further analyze the effects of perampanel, apoptosis induction was measured by caspase 3/7 activation. Glutamate release was quantified and glucose uptake was determined using 18F-fluorodeoxyglucose. Real-time polymerase chain reaction was employed to assess the expression of genes associated with glutamate release and uptake in brain tumor cells. Of the four anticonvulsants, only perampanel showed systematic inhibitory effects on cell proliferation, whereas all other anticonvulsants failed to inhibit glioma and metastasis cell growth in vitro. Metastasis cells were much more resistant to perampanel than glioblastoma cell lines. Glucose uptake was attenuated in all glioblastoma cells after perampanel exposure, whereas cell death via apoptosis was not induced. Extracellular glutamate levels were found to be significantly higher in glioblastoma cell lines as compared to metastasis cell lines, but could be reduced by perampanel exposure. Incubation with perampanel up-regulated glutamine synthetase expression in glioblastoma cells, whereas treatment with valproic acid and levetiracetam downregulated excitatory amino acid transporter-2 expression. Overall, our data suggest that perampanel acts as an anticonvulsive drug and additionally mediated anti-tumorigenic effects.

Optimized creation of glioblastoma patient derived xenografts for use in preclinical studies

Background

Glioblastoma multiforme (GBM) is the most common and lethal brain tumor in adults, highlighting the need for novel treatment strategies. Patient derived xenografts (PDX) represent a valuable tool to accomplish this task.

Methods

PDX were established by implanting GBM tissue subcutaneously. Engraftment success was compared between NMRI Foxn1^nu and NOD/SCID as well as between fresh and cryopreserved tissue. Established PDX were analyzed histologically and molecularly. Five PDX were experimentally treated with different drugs to assess their potential for preclinical drug testing.

Results

Establishment of PDX was attempted for 36 consecutive GBM cases with an overall success rate of 22.2% in NMRI Foxn1^nu mice. No difference was observed between fresh or cryopreserved (20–1057 days) tissue in direct comparison (n = 10 cases). Additionally, engraftment was better in NOD/SCID mice (38.8%) directly compared to NMRI Foxn1^nu mice (27.7%) (n = 18 cases). Molecular data and histology of the PDX compare well to the primary GBM. The experimental treatment revealed individual differences in the sensitivity towards several clinically relevant drugs.

Conclusions

The use of vitally frozen GBM tissue allows a more convenient workflow without efficiency loss. NOD/SCID mice appear to be better suited for initial engraftment of tumor tissue compared to NMRI Foxn1^nu mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1128-5) contains supplementary material, which is available to authorized users.

Expression of young HERV-H loci in the course of colorectal carcinoma and correlation with molecular subtypes

Background

Expression of the human endogenous retrovirus (HERV)-H family has been associated with colorectal carcinomas (CRC), yet no individual HERV-H locus expression has been thoroughly correlated with clinical data.

Here, we characterized HERV-H reactivations in clinical CRC samples by integrating expression profiles, molecular patterns and clinical data. Expression of relevant HERV-H sequences was analyzed by qRT-PCR on two well-defined clinical cohorts (n = 139 pairs of tumor and adjacent normal colon tissue) including samples from adenomas (n = 21) and liver metastases (n = 16). Correlations with clinical and molecular data were assessed.

Results

CRC specific HERV-H sequences were validated and found expressed throughout CRC disease progression. Correlations between HERV-H expression and lymph node invasion of tumor cells (p = 0.0006) as well as microsatellite instable tumors (p < 0.0001) were established. No association with regard to age, tumor localization, grading or common mutations became apparent. Interestingly, CRC expressed elements belonged to specific young HERV-H subfamilies and their 5′ LTR often presented active histone marks.

Conclusion

These results suggest a functional role of HERV-H sequences in colorectal carcinogenesis. The pronounced connection with microsatellite instability warrants a more detailed investigation. Thus, HERV-H sequences in addition to tumor specific mutations may represent clinically relevant, truly CRC specific markers for diagnostic, prognostic and therapeutic purposes.

Optimizing the process of nucleofection for professional antigen presenting cells

Background

In times of rapidly increasing numbers of immunological approaches entering the clinics, antigen delivery becomes a pivotal process. The genuine way of rendering antigen presenting cells (APC) antigen specific, largely influences the outcome of the immune response. Short peptides bear the demerit of HLA restriction, whereas the proper way of delivery for long peptide sequences is currently a matter of debate. Electroporation is a reliable method for antigen delivery, especially using nucleic acids. The nucleofection process is based on this approach with the twist of further ensuring delivery also into the nucleus. Beside the form of antigen, the type of APC used for immune response induction may be crucial. Dendritic cells (DC) are by far the most commonly used APC; however B cells have entered this field as well and have gained wide acceptance.

Results

In this study, we compared B cells to DC with regard to nucleofection efficiency and intensity of resulting antigen expression. APC were transfected either with plasmid DNA containing the reporter gene green fluorescent protein (GFP) or directly with in vitro-transcribed (IVT) GPF mRNA as a surrogate antigen. Out of nearly 100 different nucleofection programs tested, the top five for each cell type were identified and validated using cells from cancer patients. Flow cytometric analyses of transfected cells determining GFP expression and viability revealed a reverse correlation of efficiency and viability. Finally, donor dependant variances were analyzed.

Conclusion

In summary, nucleofection of both DC and B cells is feasible with plasmid DNA and IVT mRNA. And no differences with regard to nucleofectability were observed between the two cell types. Using IVT mRNA omits the danger of genomic integration and plasmid DNA constructs permit a more potent and longer lasting antigen expression.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1446-8) contains supplementary material, which is available to authorized users.

Tumor antigen and MHC expression in glioma cells for immunotherapeutic interventions

AIM: To investigate the expression of tumor-antigens and major histocompatibility complex (MHC)-machinery components in glioblastoma multiforme cell lines flow cytometry staining methods were applied.

METHODS: Ten GBM cell lines (three commercially available: U-87 MG, U-138-MG and GMS-10 as well as seven newly established cell lines from individual patients in low-passages: HROG02, HROG04, HROG05, HROG06, HROG10, HROG13 and HROG17) were analyzed for expression of (I) general and (II) GBM-related tumor antigens as well as of (III) components of the MHC machinery by flow cytometry.

RESULTS: All cell lines expressed MHC class I with seven out of the ten being HLA-A02 positive. Four of the seven primary cell lines additionally expressed MHC class II in a constitutive manner. Of note, after interferon gamma (IFN-γ) treatment, all seven cell lines expressed MHC class II. The tumor associated antigens (TAA) EGFR and survivin were expressed at high levels in all cell lines; whereas MART-1, RHAMM, WT-1 and IL-13Rα were expressed by at least half of the cell lines and HER2/neu, MAGE-1 and tyrosinase were expressed only by few cell lines. However, all cell lines expressed at least two of the candidate antigens included into this analysis.

CONCLUSION: No obvious differences between commercially available and newly-established cell lines were observed. Thus, the latter in low-passages are interesting for (therapy-) screening and immunotherapeutic strategies.

Establishment and characterization of primary glioblastoma cell lines from fresh and frozen material: a detailed comparison

Background

Development of clinically relevant tumor model systems for glioblastoma multiforme (GBM) is important for advancement of basic and translational biology. High molecular heterogeneity of GBM tumors is well recognized, forming the rationale for molecular tests required before administration of several of the novel therapeutics rapidly entering the clinics. One model that has gained wide acceptance is the primary cell culture model. The laborious and time consuming process is rewarded with a relative high success rate (about 60%). We here describe and evaluate a very simple cryopreservation procedure for GBM tissue prior to model establishment that will considerably reduce the logistic complexity.

Methods

Twenty-seven GBM samples collected ad hoc were prepared for primary cell culture freshly from surgery (#1) and after cryopreservation (#2).

Results

Take rates after cryopreservation (59%) were as satisfactory as from fresh tissue (63%; p = 1.000). We did not observe any relevant molecular or phenotypic differences between cell lines established from fresh or vitally frozen tissue. Further, sensitivity both towards standard chemotherapeutic agents (Temozolomide, BCNU and Vincristine) and novel agents like the receptor tyrosine kinase inhibitor Imatinib did not differ.

Conclusions

Our simple cryopreservation procedure facilitates collection, long-time storage and propagation (modeling) of clinical GBM specimens (potentially also from distant centers) for basic research, (pre-) clinical studies of novel therapies and individual response prediction.

Density functional theory investigations of NiN2S2 reactivity as a function of nitrogen donor type and N–H···S hydrogen bonding inspired by nickel-containing superoxide dismutase

Density functional theory calculations on a series of six square-planar NiN2S2 complexes have been performed. The nitrogen donor type was varied from diamino in Ni(bme-dmed), 1, to amino-amido in [Ni(mama)]-, 2, to diamido in [Ni(ema)]2-, 3. The sulfur-oxygenated derivative Ni(bme-O2-dmed), 4, and hydrogen-bonded derivatives (5 and 6) of 2 and 3 were also studied. Full geometric optimization and subsequent population analyses were performed using the 6-311g(d,p) basis set. The frontier molecular orbitals for all complexes contain significant nickel and sulfur character. Molecular electrostatic potentials show that amido nitrogen donors increase electron density at nickel relative to sulfur. Sulfur modification further shifts electron density away from the ligand towards the metal. It is proposed that the nitrogen donor type and sulfur modification may regulate sulfur-site reactivity in nickel-containing superoxide dismutase.