Immortalized Cancer Cell Lines Research Articles

Effect of human reovirus strain R-92 on tumor cell lines

Background. Among all the new methods and approaches, virotherapy with oncolytic viruses, both in combination with immunotherapy and without it, shows high efficiency in various phases of clinical trials and good tolerance by patients.Aim. To study the sensitivity of some immortalized cancer cell lines to the R-92 strain of human reovirus with cell characteristics at the ultrastructural level.Materials and methods. The study was carried out on cell lines of HeLa, A549, U87MG. Cells were planted in an amount of 15 thousand per well of a 96-well plate and after adhesion, the virus was inoculated by adding a medium containing virus particles in 4 tenfold dilutions (approximately 10 9 –106 particles per ml). Next, the cells were cultured for 24 h, after which the number of living cells in the wells was determined indirectly using the methyl tetrazolium test, which was carried out according to standard methods. To study the ultrastructure of infected cells, cells were seeded into a T25 flask and inoculated with the virus at the maximum concentration. After 24 h of cultivation, the cells were fixed in a 2.5 % glutaraldehyde solution in phosphate buffer for 1 h, after which they were washed three times in phosphate buffer and samples were processed for TEM according to standard methods.Results. Diluting the virus 1000 times led to a decrease in the cytostatic effect in all three cultures to a level practically no different from the control. HeLa turned out to be the most sensitive culture to reovirus. In the experiment, the number of living cells decreased to 60.4 ± 10.2 % compared to the control during incubation with the maximum number of viral particles and to 63.7 ± 16.2 % with a tenfold dilution of the virus. This indicator was significantly lower than in the other two studied cultures under these cultivation conditions (p <0.001).In addition, at the maximum virus concentration, the A549 culture was less sensitive than the U87MG culture (p <0.01). At lower concentrations of viral particles, the average viability of the studied cell lines did not differ significantly from each other. Analysis of electron diffraction patterns showed that the virus successfully replicates in the cytoplasm of the studied cultures, but is not released from the cell, which is apparently due to the short incubation period. TEM also showed cell damage characteristic of apoptosis or necroptosis, uniformly expressed in all studied cultures.Conclusion. Cell lines A549, HeLa and U87MG, according to the results of the methyl tetrazolium test, demonstrate different sensitivity to the human reovirus strain P-92. The TEM picture of cells from infected cultures showed signs of the development of apoptosis or necroptosis.

Tropomyosin1 isoforms underlie epithelial to mesenchymal plasticity, metastatic dissemination, and resistance to chemotherapy in high-grade serous ovarian cancer

Phenotypic plasticity, defined as the ability of individual cells with stable genotypes to exert different phenotypes upon exposure to specific environmental cues, represent the quintessential hallmark of the cancer cell en route from the primary lesion to distant organ sites where metastatic colonization will occur. Phenotypic plasticity is driven by a broad spectrum of epigenetic mechanisms that allow for the reversibility of epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions (EMT/MET). By taking advantage of the co-existence of epithelial and quasi-mesenchymal cells within immortalized cancer cell lines, we have analyzed the role of EMT-related gene isoforms in the regulation of epithelial mesenchymal plasticity (EMP) in high grade serous ovarian cancer. When compared with colon cancer, a distinct spectrum of downstream targets characterizes quasi-mesenchymal ovarian cancer cells, likely to reflect the different modalities of metastasis formation between these two types of malignancy, i.e. hematogenous in colon and transcoelomic in ovarian cancer. Moreover, upstream RNA-binding proteins differentially expressed between epithelial and quasi-mesenchymal subpopulations of ovarian cancer cells were identified that underlie differential regulation of EMT-related isoforms. In particular, the up- and down-regulation of RBM24 and ESRP1, respectively, represent a main regulator of EMT in ovarian cancer cells. To validate the functional and clinical relevance of our approach, we selected and functionally analyzed the Tropomyosin 1 gene (TPM1), encoding for a protein that specifies the functional characteristics of individual actin filaments in contractile cells, among the ovarian-specific downstream AS targets. The low-molecular weight Tpm1.8/9 isoforms are specifically expressed in patient-derived ascites and promote invasion through activation of EMT and Wnt signaling, together with a broad spectrum of inflammation-related pathways. Moreover, Tpm1.8/9 expression confers resistance to taxane- and platinum-based chemotherapy. Small molecule inhibitors that target the Tpm1 isoforms support targeting Tpm1.8/9 as therapeutic targets for the development of future tailor-made clinical interventions.

Non-mitotic proliferation of malignant cancer cells revealed through live-cell imaging of primary and cell-line cultures

IntroductionAnti-mitosis has been a key strategy of anti-cancer therapies, targeting at a fundamental property of cancer cells, their non-controllable proliferation due to overactive mitotic divisions. For improved anti-cancer therapies, it is important to find out whether cancer cells can proliferate independent of mitosis and become resistant to anti-mitotic agents.ResultsIn this study, live-cell imaging was applied to both primary-cultures of tumor cells, and immortalized cancer cell lines, to detect aberrant proliferations. Cells isolated from various malignant tumors, such as Grade-III hemangiopericytoma, atypical meningioma, and metastatic brain tumor exhibit distinct cellular behaviors, including amoeboid sequestration, tailing, tunneling, nucleic DNA leakage, as well as prokaryote-like division such as binary fission and budding-shedding, which are collectively referred to and reported as ‘non-mitotic proliferation’ in this study. In contrast, benign tumors including Grade-I hemangiopericytoma and meningioma were not obvious in such behaviors. Moreover, when cultured in medium free of any anti-cancer drugs, cells from a recurrent Grade-III hemangiopericytoma that had been subjected to pre-operation adjuvant chemotherapy gradually shifted from non-mitotic proliferation to abnormal mitosis in the form of daughter number variation (DNV) and endomitosis, and eventually regular mitosis. Similarly, when treated with the anti-cancer drugs Epirubicin or Cisplatin, the cancer cell lines HeLa and A549 showed a shift from regular mitosis to abnormal mitosis, and further to non-mitosis as the dominant mode of proliferation with increasing drug concentrations. Upon removal of the drugs, the cells reversed back to regular mitosis with only minor occurrences of abnormal mitosis, accompanied by increased expression of the stem cell markers ALDH1, Sox, Oct4 and Nanog.ConclusionsThe present study revealed that various types of malignant, but not benign, cancer cells exhibited cellular behaviors indicative of non-mitotic proliferation such as binary fission, which was typical of prokaryotic cell division, suggesting cell level atavism. Moreover, reversible transitions through the three modes of proliferation, i.e., mitosis, abnormal mitosis and non-mitosis, were observed when anticancer drug concentrations were grossly increased inducing non-mitosis or decreased favoring mitosis. Potential clinical significance of non-mitotic proliferation in cancer drug resistance and recurrence, and its relationship with cancer stem cells are worthy of further studies.

Novel human STING activation by hydrated-prenylated xanthones from Garcinia cowa.

We investigate the anticancer activity and human stimulator of interferon genes pathway activation by a new hydrated-prenylated tetraoxygenated xanthone, garcicowanone I (1) and two known xanthones (2 and 3) that were isolated from the root bark of Garcinia cowa Roxb. ex Choisy. The anticancer activity of each compound was evaluated by sulforhodamine B assay in immortalized cancer cell lines. Stimulator of interferon genes pathway activation was assessed by western blot analysis using human THP-1-derived macrophages. The production of pro-inflammatory cytokines from these macrophages was also evaluated via enzyme-linked immunosorbent assay. Both compounds 1 and 3 displayed moderate inhibitory effects on the cancer cells, including a cisplatin-resistant cell line, with IC50 values in the range of 10-20 µM. All three xanthones activated the stimulator of interferon genes, as evidenced by phosphorylation of tank-binding kinase 1, the stimulator of interferon genes protein and interferon regulatory factor 3. Furthermore, treatment of these macrophages with compounds 1-3 led to the production of pro-inflammatory cytokines, including interleukin 6, tumour necrosis factor α and interleukin 1β. In conclusion, the isolated xanthones, including the novel garcicowanone I, displayed promising anticancer and immunomodulatory activity that warrants further research.

Replacement, Reduction, and Refinement of Animal Experiments in Anticancer Drug Development: The Contribution of 3D In Vitro Cancer Models in the Drug Efficacy Assessment.

In the last decades three-dimensional (3D) in vitro cancer models have been proposed as a bridge between bidimensional (2D) cell cultures and in vivo animal models, the gold standards in the preclinical assessment of anticancer drug efficacy. 3D in vitro cancer models can be generated through a multitude of techniques, from both immortalized cancer cell lines and primary patient-derived tumor tissue. Among them, spheroids and organoids represent the most versatile and promising models, as they faithfully recapitulate the complexity and heterogeneity of human cancers. Although their recent applications include drug screening programs and personalized medicine, 3D in vitro cancer models have not yet been established as preclinical tools for studying anticancer drug efficacy and supporting preclinical-to-clinical translation, which remains mainly based on animal experimentation. In this review, we describe the state-of-the-art of 3D in vitro cancer models for the efficacy evaluation of anticancer agents, focusing on their potential contribution to replace, reduce and refine animal experimentations, highlighting their strength and weakness, and discussing possible perspectives to overcome current challenges.

Bioresource collection of cell lines and primary tumors of the National Medical Research Center of Oncology of the Ministry of Health of Russia

The Biobank of the National Medical Research Center of Oncology is a multi-layered infrastructure with large collections of biological samples, complemented by extensive and well-annotated clinical and pathological patient data, including medical images, pathological histology, and molecular analysis of biosamples. To date, the biobank of the National Medical Research Center of Oncology contains collections of primary and immortalized cancer cell lines of human origin. The collection of primary cell lines was formed from samples of postoperative material taken during the removal of tumors of various localizations (breast cancer, prostate cancer, lung cancer). All cell lines underwent internal quality control for contaminants (exogenous viruses, mycoplasmas and bacterial L-forms), viability and were cultivated without antibiotics. On the basis of the collected samples, a significant number of projects in the field of biomedicine were carried out, the results of which are described in this article.

Multifactorial drug response modeling based on cancer organoid data.

e13544 Background: Prediction of drug response based on cancer molecular profiles is of paramount importance for precision oncology. Most existing drug response prediction models are built using drug screening data of immortalized cancer cell lines, which usually have altered genomic profiles compared with patient tumors. Recently, patient-derived organoids (PDOs) are emerging as a promising platform better representing patient tumors. We build computational drug response prediction models based on PDO drug screening data, which is the first study of its type to our knowledge. Methods: We successfully developed 27 PDO lines of colorectal cancer and 20 PDO lines of head and neck (H&N) cancer. Transcriptomics, copy number variation (CNV), and targeted DNA mutation data were generated for the PDO lines. The PDO lines were screened with 36 drugs of diversified mechanisms. The area under the dose response curve was taken as the response measurement. We used the LightGBM algorithm to build response prediction models based on cancer molecular data and drug chemical descriptors/fingerprints. To investigate the influence of different factors on the prediction performance, including different cancer types, cancer molecular features, drug features, data preprocessing methods, and others, we applied a multifactorial analysis scenario to build and evaluate 3,384 prediction models constructed with all possible combinations of the factors. For example, we built prediction models for H&N and colorectal PDOs separately and jointly. Results: A prediction model built for H&N PDOs achieved the highest prediction performance among all prediction models, which was R2 of 0.790 in 10-fold cross-validation. The model was built using drug descriptors, CNVs, and expressions of “landmark” genes well-representing cellular transcriptomic changes identified in the LINCS project. The table below includes all the factorial differences that caused an average R2 change larger than 1%. All R2 changes are statistically significant (p-values < 1×10–50), evaluated by pair-wise t-tests comparing models built with the status of the factor changed. The prediction performance increased, from colorectal cancer to two cancer types combined, and to H&N cancer. Gene expression data, either whole-transcriptome or the subset of LINCS genes, boosted the prediction performance. Between the two different dyes used to stain dead cells, TO-PRO-3 provided a higher prediction performance than Caspase-3/7. Conclusions: The highest drug response prediction performance achieved is R2 of 0.790. Cancer type, dye, and whether gene expressions are used in modeling are the factors most influential on prediction performance.[Table: see text]

The Diverse Applications of Pancreatic Ductal Adenocarcinoma Organoids.

Simple SummaryPatients diagnosed with pancreatic cancer have very few treatment options. In order to identify new treatment opportunities, and develop new drugs for clinical use, appropriate model systems that take into account the complexities of a tumor are required. In this review, we summarize the current and emerging opportunities to accurately model pancreatic cancer using organoid technologies. We highlight the need for continued development of these complex model systems in order to inform personalized treatment. Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies. While immortalized cancer cell lines and genetically engineered murine models have increased our understanding of PDAC tumorigenesis, they do not recapitulate inter- and intra-patient heterogeneity. PDAC patient derived organoid (PDO) biobanks have overcome this hurdle, and provide an opportunity for the high throughput screening of potential new therapies. This review provides a summary of the PDAC PDO biobanks established to date, and discusses how they have advanced our understanding of PDAC biology. Looking forward, the development of coculturing techniques for specific immune or stromal cell populations will enable a better understanding of the crosstalk that occurs within the tumor microenvironment, and the impact of this crosstalk on treatment response.

Novel immunomodulatory properties of low dose cytarabine entrapped in a mannosylated cationic liposome

Cancer treatment remains unsatisfactory with high rates of recurrence and metastasis. Immunomodulatory agents capable of promoting cellular antitumor immunity while inhibiting the local immunosuppressive tumor microenvironment could greatly improve cancer treatment. We have developed a multi-targeted mannosylated cationic liposome delivery system containing muramyl dipeptide (DS) and low doses of the chemotherapeutic agent cytarabine (Ara-C). Immunomodulation of primary immune cells and immortalized cancer cell lines by Ara-C/DS was assessed by measuring cytokine levels and surface marker expression. As a proof of concept, the generation of targeted cellular immunity was investigated in the context of responses to viral antigens. This report is the first demonstrating that Ara-C combined with DS can modulate immune responses and revert immunosuppression as evidenced by increased IFN-γ and IL-12p40 without changes in IL-10 in peripheral blood mononuclear cells, and increased CD80 and decreased CD163 on immunosuppressive macrophages. Furthermore, Ara-C/DS increased MHC class I expression on cancer cells while increasing the production of antigen-specific IFN-γ+ CD8+ T cells in viral peptide-challenged lymphocytes from both humans and vaccinated mice. Taken together, these results are the first to document immunomodulatory properties of Ara-C linked with recognition of antigens and potentially the generation of antitumor immune memory.

Establishment and characterization of immortalized human breast cancer cell lines from breast cancer patient-derived xenografts (PDX)

The application of patient-derived xenografts (PDX) in drug screening and testing is a costly and time-consuming endeavor. While cell lines permit extensive mechanistic studies, many human breast cancer cell lines lack patient characteristics and clinical treatment information. Establishing cell lines that retain patient’s genetic and drug response information would enable greater drug screening and mechanistic studies. Therefore, we utilized breast cancer PDX from the Mayo Breast Cancer Genome Guided Therapy Study (BEAUTY) to establish two immortalized, genomically unique breast cancer cell lines. Through extensive genetic and therapeutic testing, the cell lines were found to retain the same clinical subtype, major somatic alterations, and drug response phenotypes as their corresponding PDX and patient tumor. Our findings demonstrate PDX can be utilized to develop immortalized breast cancer cell lines and provide a valuable tool for understanding the molecular mechanism of drug resistance and exploring novel treatment strategies.

Isolation and Establishment of a Highly Proliferative, Cancer Stem Cell-Like, and Naturally Immortalized Triple-Negative Breast Cancer Cell Line, KAIMRC2.

In vitro studies of a disease are key to any in vivo investigation in understanding the disease and developing new therapy regimens. Immortalized cancer cell lines are the best and easiest model for studying cancer in vitro. Here, we report the establishment of a naturally immortalized highly tumorigenic and triple-negative breast cancer cell line, KAIMRC2. This cell line is derived from a Saudi Arabian female breast cancer patient with invasive ductal carcinoma. Immunocytochemistry showed a significant ratio of the KAIMRC2 cells’ expressing key breast epithelial and cancer stem cells (CSCs) markers, including CD47, CD133, CD49f, CD44, and ALDH-1A1. Gene and protein expression analysis showed overexpression of ABC transporter and AKT-PI3Kinase as well as JAK/STAT signaling pathways. In contrast, the absence of the tumor suppressor genes p53 and p73 may explain their high proliferative index. The mice model also confirmed the tumorigenic potential of the KAIMRC2 cell line, and drug tolerance studies revealed few very potent candidates. Our results confirmed an aggressive phenotype with metastatic potential and cancer stem cell-like characteristics of the KAIMR2 cell line. Furthermore, we have also presented potent small molecule inhibitors, especially Ryuvidine, that can be further developed, alone or in synergy with other potent inhibitors, to target multiple cancer-related pathways.

Spectroscopic Analysis of a Library of DNA Tension Probes for Mapping Cellular Forces at Fluid Interfaces.

Oligonucleotide-based probes offer the highest spatial resolution, force sensitivity, and molecular specificity for cellular tension sensing and have been developed to measure a variety of molecular forces mediated by individual receptors in T cells, platelets, fibroblasts, B-cells, and immortalized cancer cell lines. These fluorophore-oligonucleotide conjugate probes are designed with a stem-loop structure that engages cell receptors and reversibly unfolds due to mechanical strain. With the growth of recent work bridging molecular mechanobiology and biomaterials, there is a need for a detailed spectroscopic analysis of DNA tension probes that are used for cellular imaging. In this manuscript, we conducted an analysis of 19 DNA hairpin-based tension probe variants using molecular dynamics simulations, absorption spectroscopy, and fluorescence imaging (epifluorescence and fluorescence lifetime imaging microscopy). We find that tension probes are highly sensitive to their molecular design, including donor and acceptor proximity and pairing, DNA stem-loop structure, and conjugation chemistry. We demonstrate the impact of these design features using a supported lipid bilayer model of podosome-like adhesions. Finally, we discuss the requirements for tension imaging in various biophysical contexts and offer a series of experimental recommendations, thus providing a guide for the design and application of DNA hairpin-based molecular tension probes.

Betulinic Acid-Azaprostanoid Hybrids: Synthesis and Pharmacological Evaluation as Anti-inflammatory Agents

Background: Prevention and treatment of chronic inflammatory diseases require effective and low-toxic medicines. Molecular hybridization is an effective strategy to enhance the biological activity of new compounds. Triterpenoid scaffolds are in the focus of attention owing to their anti-inflammatory, antiviral, antiproliferative, and immunomodulatory activities. Heteroprostanoids have different pleiotropic effects in acute and chronic inflammatory processes.Objective: The study aimed to develop structurally new and low toxic anti-inflammatory agents via hybridization of betulinic acid with azaprostanoic acids.Methods: A series of betulinic acid-azaprostanoid hybrids was synthesized. The synthetic pathway included the transformation of betulin via Jones' oxidation into betulonic acid, reductive amination of the latter and coupling obtained by 3β-amino-3-deoxybetulinic acid with the 7- or 13-azaprostanoic acids and their homo analogues. The hybrids 1-9 were investigated in vivo on histamine-, formalin- and concanavalin A-induced mouse paw edema models and two models of pain - the acetic acid-induced abdominal writhing and the hot-plate test. The hybrids were in vitro evaluated for cytotoxic activity on cancer (MCF7, U-87 MG) and non-cancer humane cell lines.Results: In the immunogenic inflammation model, the substances showed a pronounced anti-inflammatory effect, which was comparable to that of indomethacin. In the models of the exudative inflammation, none of the compounds displayed a statistically significant effect. The hybrids produced weak or moderate analgesic effects. All the agents revealed low cytotoxicity on human immortalized fibroblasts and cancer cell lines compared with 3β-amino-3-deoxybetulinic acid and doxorubicin.Conclusion: The results indicate that the principal anti-inflammatory effect of hybrids is substantially provided with the triterpenoid scaffold and in some cases with the azaprostanoid scaffold, but the latter makes a significant contribution to reducing the toxicity of hybrids. Hybrid 1 is of interest as a potent low toxic agent against immune-mediated inflammation.

Abstract 3366: In vivo efficacy of a PD-L1 targeted, antigen seeding engineered toxin body

Abstract Engineered toxin bodies (ETBs) comprised of a proprietarily engineered Shiga-like Toxin A subunit (SLTA) genetically fused to antibody-like binding domains work through novel mechanisms of action and can force internalization, self-route through intracellular compartments to the cytosol, and induce potent cell-kill via the enzymatic and permanent inactivation of ribosomes. Our PD-L1 targeted ETB, MT-6402, includes antigen seeding technology (AST), and additionally delivers a viral antigen for presentation in complex with MHC-I to resident viral-specific cytotoxic T lymphocytes (CTLs). The fusion protein provides a powerful, dual mechanism of action to specifically target and destroy PD-L1 positive tumor and inhibitory immune cells. In vitro testing of human tumor cell lines has demonstrated that cell surface PD-L1 expression is required for activity of the PD-L1 targeted ETBs. MT-6402 demonstrated effective depletion of PD-L1 expressing cells across a panel of immortalized cancer cell lines from multiple origins, including lung, skin, breast, and ovary. In a co-culture assay of PD-L1 target cells and antigen specific T-cells, PD-L1 targeted MT-6402 delivers a viral antigen to the target cells and can activate cytokine secretion and T-cell mediated killing. Additionally, MT-6402 treatment of human peripheral blood mononuclear cells (PBMCs) leads to selective depletion of PD-L1 positive cells (IFN-γ stimulated monocytes) in the absence of depletion of PD-L1 low/negative lymphocytes. Murine models, including patient derived xenografts, have demonstrated that the PD-L1 targeted ETBs are efficacious in vivo. Additional in vivo tumor models to further describe the effect of MT-6402 are being explored. Exploratory studies in a primate model have shown that MT-6402 can be tolerated at levels shown to induce T cell activation (type 1 cytokines). MT-6402 delivers a powerful and unique dual mechanism of action. The combination of a PD-L1 specific direct cell kill and redirection of a robust effector T cell response to the tumor has potential benefit in solid tumor indications, including in the relapsed setting, when disease has progressed after checkpoint and/or other therapies. Citation Format: Hilario J. Ramos, Brigitte Brieschke, Sara LeMar, Joseph D. Dekker, Aimee Iberg, Garrett L. Robinson, Asis Sarkar, Banmeet Anand, Melissa M. Singh, Jay Zhao, Jack P. Higgins, Erin K. Willert. In vivo efficacy of a PD-L1 targeted, antigen seeding engineered toxin body [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3366.

Characterization and comparison of genomic profiles between primary cancer cell lines and parent atypical meningioma tumors

BackgroundMeningiomas are the second most common primary tumors of the central nervous system. However, there is a paucity of data on meningioma biology due to the lack of suitable preclinical in vitro and in vivo models. In this study, we report the establishment and characterization of patient-derived, spontaneously immortalized cancer cell lines derived from World Health Organization (WHO) grade I and atypical WHO grade II meningiomas.MethodsWe evaluated high-resolution 3T MRI neuroimaging findings in meningioma patients which were followed by histological analysis. RT-qPCR and immunostaining analyses were performed to determine the expression levels of meningioma-related factors. Additionally, flow cytometry and sorting assays were conducted to investigate and isolate the CD133 and CD44 positive cells from primary atypical meningioma cells. Further, we compared the gene expression profiles of meningiomas and cell lines derived from them by performing whole-exome sequencing of the blood and tumor samples from the patients, and the primary cancer cell lines established from the meningioma tumor.ResultsOur results were consistent with earlier studies that reported mutations in NF2, SMO, and AKT1 genes in atypical meningiomas, and we also observed mutations in MYBL2, a gene that was recently discovered. Significantly, the genomic signature was consistent between the atypical meningioma cancer cell lines and the tumor and blood samples from the patient.ConclusionOur results lead us to conclude that established meningioma cell lines with a genomic signature identical to tumors might be a valuable tool for understanding meningioma tumor biology, and for screening therapeutic agents to treat recurrent meningiomas.

Abstract C093: An interactive resource to probe ancestry in cancer cell lines

Abstract Recent work has pointed to a lack of diversity in genomics studies from genome-wide association studies to somatic (tumor) genome analyses. Yet, population-specific variation has been shown to contribute to health disparities in cancer risk and prognosis. Immortalized cancer cell lines have been widely used for various aspects of cancer research from mechanistic studies to drug screening. More recently, larger collections of cancer cell lines have been developed with the objective of better representing the genomic heterogeneity found in primary tumors. The genetic ancestral origin of cancer cell line models is rarely acknowledged and often unknown. Genome-wide genotyping data (Affymetrix SNP6.0 array) was obtained for 1,393 cancer cell lines from the Catalogue of Somatic Mutations in Cancer (COSMIC) and Cancer Cell Line Encyclopedia (CCLE) collections. Clustering of the cell lines in relation to reference populations of the 1000 Genomes project was visualized using t-Distributed Stochastic Neighbor Embedding (t-SNE) plots. Ancestry proportions constituting each cell line were estimated using the program Admixture. For over 46% of the cell lines analyzed, ethnicity has not been reported in public databases. The ancestral origins of the cell lines, as measured by genetic markers, were distributed as follow: European 58.1%, East Asian 28.8%, African 1.4%, South Asian <1%, mixed ancestry 11.4%. We also noticed several inaccuracies when comparing reported ethnicity to the ancestry observed from genomic data. Of the 44 cell lines reported as African or Black, 27.0% showed diverse degrees of admixture, with a European component reaching up to 37.5%. Inversely, a proportion of the cell lines reported as Caucasian or white did include admixed cell lines with strong African genetic contribution (up to 86.8%), while others showed patterns of admixture similar to Hispanic populations. Furthermore, we present an interactive online tool, Cell Line Estimated Ancestry Resource (CLEAR), where ancestry can be visualized in relation to reference populations of the 1000 Genomes project. Our data indicate that the collection of cell lines commonly used in cancer research is not representative of the diverse ancestry and admixture characterizing human populations. In addition, we demonstrate that the reported information on ethnicity contains inaccuracies and rarely acknowledges the mixed origins of their genetic background. These observations are likely to impact the reproducibility of studies relying on those models and the relevance of the findings to diverse populations. Citation Format: Zhihua Chen, Alvaro N. Monteiro, Jamie K. Teer, Steven Eschrich, Julie Dutil. An interactive resource to probe ancestry in cancer cell lines [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C093.

Drug Development Based on Intracellular Pharmacokinetic Analysis of Molecular Target Drug in Mice Bearing Patient-derived Xenograft Model

Traditionally, anticancer drug discovery research has been conducted based on immortalized cancer cell lines, either cultured in vitro or grown in vivo. In the USA and Europe, patient derived xenograft (PDX) model is rapidly expelling traditional in vitro and in vivo models due to the good predictability of clinical outcome and its nature of retaining characteristics and heterogeneity in the original tumor. Furthermore, a significant association was also reported between drug responses in patient and corresponding PDX as high as 87%. We are preparing a PDX model for Japanese cancer patients including drug resistance examples and rare cancers. Using the established PDX model, we confirmed the possibility that the tumor microenvironment might affect the efficacy and distribution of drugs even if the target receptor is expressed in tumor sites as compared to the cell line (CDX) model, which has been widely used in drug discovery. Interestingly, although expressing a target receptor in viable tumor cells, we also have found a PDX model with a lower distribution of molecular target drug. Therefore we will evaluate the usefulness of the PDX model in drug development by exploring new biomarkers and elucidating the mechanisms of drug resistance in target tumors. Moreover, pharmaco-imaging system will allow us to visualize the exposure and distribution of drugs in tumors at macro and micro levels. Finally, we evaluate relations between distribution of drugs in the tumor microenvironment including target tumor cells, neovessels, stromal cells, immune cells, and fibroblasts.

Bioengineered Cancer-Fibroblast Interactions in Patient-Derived Colorectal Cancer Organoid Models

The development of patient-derived organoid (PDO) technologies has greatly expanded the toolbox for drug discovery and personalized drug screening for several cancer types. While PDO models more closely represent the molecular characteristics and heterogeneity of patient tumors than traditional immortalized cancer cell lines, they are inherently limited in their ability to reflect the tumor microenvironment in vitro as they comprise exclusively of epithelial cells. The lack of stromal cells in PDO models, such as cancer-associated fibroblasts (CAFs), poses a major problem as these tumor microenvironmental components contribute to the various hallmarks of cancer and response to therapy. Particularly for colorectal cancer, CAFs comprise the majority of the tumor microenvironment and play important roles in cancer progression and drug resistance. In this study, we addressed this problem by establishing in vitro conditions that robustly enable the co-culture of CRC PDO with patient-derived CAFs. We report the development of an engineered tumor microenvironment consisting of CRC PDO encapsulated within a well-defined three-dimensional (3D) hyaluronan-gelatin hydrogel and co-cultured with patient-derived CAFs. Basement membrane extracts conventionally used for PDO culture exhibit batch-to-batch variability. Considering that the CRC extracellular matrix is high in hyaluronan and collagen I, and that hyaluronan-based matrices have been shown to be conducive for the culture of various human cancers, we hypothesized that hyaluronan-gelatin hydrogels may serve as a suitable alternative 3D matrix to support the co-culture of CRC PDO and CAFs. Through RNA- and whole-exome sequencing, we first show that these hydrogels are capable of maintaining key molecular characteristics of the original patient tumors in CRC PDO but not support the culture of CAFs. Further, based on our findings that CRC PDO culture medium poorly supports CAF viability, we developed a co-culture strategy that maintains the viability of both CRC PDO and CAFs. We found that in the absence of growth factors added to the co-culture, CAFs were able to maintain the proliferation of the cultured CRC PDO in the hydrogels and restore distinct biological pathways absent in the PDO culture alone but present in patient tissues. Lastly, we demonstrate that these CRC PDO-CAFs models are suitable for evaluating standard-of-care drugs, making them potentially very useful for realizing personalized cancer medicine.

An Interactive Resource to Probe Genetic Diversity and Estimated Ancestry in Cancer Cell Lines.

Recent work points to a lack of diversity in genomics studies from genome-wide association studies to somatic (tumor) genome analyses. Yet, population-specific genetic variation has been shown to contribute to health disparities in cancer risk and outcomes. Immortalized cancer cell lines are widely used in cancer research, from mechanistic studies to drug screening. Larger collections of cancer cell lines better represent the genomic heterogeneity found in primary tumors. Yet, the genetic ancestral origin of cancer cell lines is rarely acknowledged and often unknown. Using genome-wide genotyping data from 1,393 cancer cell lines from the Catalogue of Somatic Mutations in Cancer (COSMIC) and Cancer Cell Line Encyclopedia (CCLE), we estimated the genetic ancestral origin for each cell line. Our data indicate that cancer cell line collections are not representative of the diverse ancestry and admixture characterizing human populations. We discuss the implications of genetic ancestry and diversity of cellular models for cancer research and present an interactive tool, Estimated Cell Line Ancestry (ECLA), where ancestry can be visualized with reference populations of the 1000 Genomes Project. Cancer researchers can use this resource to identify cell line models for their studies by taking ancestral origins into consideration.

A robust culture method for maintaining tumorigenic cancer stem cells in the hepatocellular carcinoma cell line Li-7.

Cancer tissues contain small populations of highly tumorigenic cells termed cancer stem cells (CSCs). Immortalized cell lines containing CSCs are valuable and powerful experimental tools for research into the characteristics of these stem cells. We previously reported that the hepatocellular carcinoma cell line Li‐7 includes abundant CD13+ CD166− CSCs; however, the number of these cells decreases after long‐term culture as a result of differentiation to non‐CSC populations. To ensure consistent and reproducible results in experiments using Li‐7 cells, it is important that the CSC population is maintained stably regardless of culture duration and passage. In the present study, we found that a commercially available culture medium for maintenance of embryonic stem cells and induced pluripotent stem cells, mTeSR1, effectively prevented spontaneous differentiation by CD13+ CD166− cells to CD13− CD166+ cells and therefore maintained the CSC population in Li‐7 cell cultures. CD13+ CD166− CSCs maintained using this culture medium retained high tumorigenicity after transplantation into mice; they also showed the ability to differentiate in vitro into non‐CSC populations in RPMI‐1640 with 10% FBS medium. We analyzed gene expression profiles of CSC and non‐CSC populations in Li‐7 cultures using an RNA sequencing method. Genes such as FGFR, NOTCH1, and JAG1, that are associated with tumorigenicity and stemness, were upregulated in the CSC population. Our results suggest that CSCs can be maintained in immortalized cancer cell lines cultured over an extended period using a medium developed for culture of embryonic/induced pluripotent stem cells.