Cultured Tumor Cells Research Articles

β-Catenin activation and illicit receptor expression in adrenocortical cells.

Adrenal cortisol-producing tumors can express illicit membrane receptors such as luteinizing hormone (LH), glucose-dependent insulinotropic peptide (GIP) or type 4 and 7 serotonin (5-HT4/7) receptors. Abnormal expression of the LH receptor (LH-R) has been ascribed to the activation of the Wnt/β-catenin signaling pathway in adrenocortical cells. In the present study, we have investigated whether β-catenin activation may also trigger the illegitimate expression of GIP and 5-HT receptors. Three models of β-catenin activation in adrenocortical cells were used: an APC-mutated adrenocortical tumor, human-transfected adrenocortical cells and genetically modified mouse adrenal glands. The methods employed include quantitative reverse transcription PCR, immunohistochemistry and measurement of cortisol secretion by cultured tumor cells. Abnormal expression of the GIP, 5-HT7and LH receptors was observed in the APC-mutated adrenocortical tumor tissue. In addition, GIP, 5-HT and human chorionic gonadotropin stimulated cortisol production from tumor cells in primary culture. Conversely, only the LHCGR was upregulated in human and mouse adrenocortical cells harboring the activation of β-catenin. Moreover, LH-R immunoreactivity was detected in clusters of zona fasciculata cells in the β-catenin-activated mouse model. Our data indicate that activation of the β-catenin signaling pathway can promote the illicit expression of functional LH-Rs in adrenal zona fasciculata cells but does not favor the abnormal expression of GIP and 5-HT receptors.

RNA Sequencing and Cell Models of Virus-Associated Cancer (Review).

The review summarizes findings from the studies based on the application of technologies for transcriptome analysis to modern cellular model systems of human papillomavirus-associated cancer (HPV) (cervical cancer, head and neck tumors). A diversity of three-dimensional cancer models, such as spheroids, organoids (organotypic cultures), explants, mouse xenografts, are addressed. Particular attention is paid to the use of patient-derived biomaterial for establishing short-term cultures of primary tumor cells, as well as generating multicomponent (heterocellular) systems that comprise, together with the tumor component, other elements of its microenvironment. A number of unique biological properties of HPV-induced neoplasia are discussed, which make generating cell models a unique task.The novel findings in the field of molecular mechanisms of the onset and progression of HPV-associated cancer achieved by using RNA sequencing are presented for each variant of the model systems. These findings are considered in regard to applied aspects of their use, in terms of the opportunities for preclinical testing of new drugs, personalized diagnostics and selection of individual, most effective treatment regimens. The issues of drug resistance development, molecular-cellular heterogeneity, epigenetic reprogramming, and the role of the stromal microenvironment are reviewed. The paper accentuates the problems related to the limitations of the applicability of a particular model system. The areas with a significant lagging behind in omics research of virus-associated cancer in comparison with other types of oncological pathology and possible causes of this lag are noted. The future prospects for the development of model systems of HPV-associated tumors in the field of high-tech tissue engineering, in particular, the use of bioprinting and microfluidic biochips, are also outlined. The combination of these techniques with the methods of whole genome profiling will significantly increase the translational potential of the described model cell systems.

Instructive Hydrogels for Primary Tumor Cell Culture: Current Status and Outlook.

Primary tumor organoids (PTOs) growth in hydrogels have emerged as an important in vitro model that recapitulates many characteristics of the native tumor tissue, and have important applications in fundamental cancer research and for the development of useful therapeutic treatment. This paper begins with reviewing the methods of isolation of primary tumor cells. Then, recent advances on the instructive hydrogels as biomimetic extracellular matrix for primary tumor cell culture and construction of PTO models are summarized. Emerging microtechnology for growth of PTOs in microscale hydrogels and the applications of PTOs are highlighted. This paper concludes with an outlook on the future directions in the investigation of instructive hydrogels for PTO growth.

Disulfiram-loaded metal organic framework for precision cancer treatment via ultrasensitive tumor microenvironment-responsive copper chelation and radical generation

Off-target toxicity remains a major limitation of current cancer therapy, necessitating an alternative precision approach to treat cancers. Herein, a tumor microenvironment (TME)-triggered anticancer strategy was developed by constructing an anti-alcoholism drug disulfiram (DSF)-loaded, Cu-doped zeolite imidazolate frameworks-8 (DSF-Cu/ZIF-8) nanoparticle followed by PEGylation (PEG-DSF-Cu/ZIF-8) to realize in situ generation of cytotoxic compounds specifically in TME. The PEG-DSF-Cu/ZIF-8 demonstrated excellent hydrolytic stability in normal physiological conditions, guaranteeing the minimized off-target release of disulfiram and Cu ions. Under the TME condition, the PEG-DSF-Cu/ZIF-8 exhibited acidity-triggered biodegradation and the associated payload release, through which low-toxic compounds (disulfiram and Cu2+ ions) were converted to highly cytotoxic Cu-chelate product to kill cells specifically in TME. Tumor-sensitive anti-cancer performance was further enhanced by hydroxyl radical generation via TME-responsive Fenton-like reactions catalyzed by Cu+ presenting in the PEG-DSF-Cu/ZIF-8 structure and Cu+ produced during formation of the chelate product. Anti-cancer therapeutic evaluation was performed in 2D 4T1 tumor cell culture and 3D 4T1 tumor spheroids, and demonstrated highly TME-responsive, low-dose induced anti-cancer effect. This proof-of-concept work provides a nanoparticle-based drug repurposing strategy by developing a tumor-sensitive anti-cancer agent for low-toxic and efficacious cancer therapy.

A loofah-inspired scaffold with enhanced mimicking mechanics and tumor cells distribution for in vitro tumor cell culture platform

Tumor cells cultured in a physiologically related three-dimensional (3D) matrix can replicate many basic characteristics of tumor tissue. Tumor tissues are harder than normal, so when using hydrogels for 3D tumor cell culture, attempts have been made to prepare hydrogel scaffolds that mimic the hardness of tumor tissues without reducing the porosity. In this study, a new 3D loofah-inspired scaffold was developed for prostate cancer cell culture. Since the loofah sponge structure of the spacer fabric, the composite scaffolds had a compression modulus similar to that of natural prostate tumor tissue at a lower hydrogel concentration (0.25% W/V), and also, endowed the scaffold with high porosity (85 ± 2.52%) for mass transfer. The results of in vitro cell experiments showed that the composite scaffold can support tumor cells to form clusters in a short time (3 days). Preliminary chemosensitivity analysis showed that the drug resistance of the composite scaffold was significantly higher than that of two-dimensional (2D) culture and COL scaffold. Therefore, the 3D tumor cell culture scaffold with bionic structures has the potential to be used as a tumor drug screening model.

CFLIP downregulation is an early event required for endoplasmic reticulum stress-induced apoptosis in tumor cells

Protein misfolding or unfolding and the resulting endoplasmic reticulum (ER) stress frequently occur in highly proliferative tumors. How tumor cells escape cell death by apoptosis after chronic ER stress remains poorly understood. We have investigated in both two-dimensional (2D) cultures and multicellular tumor spheroids (MCTSs) the role of caspase-8 inhibitor cFLIP as a regulator of the balance between apoptosis and survival in colon cancer cells undergoing ER stress. We report that downregulation of cFLIP proteins levels is an early event upon treatment of 2D cultures of colon cancer cells with ER stress inducers, preceding TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) upregulation, caspase-8 activation, and apoptosis. Maintaining high cFLIP levels during ER stress by ectopic expression of cFLIP markedly inhibits ER stress-induced caspase-8 activation and apoptosis. Conversely, cFLIP knockdown by RNA interference significantly accelerates caspase-8 activation and apoptosis upon ER stress. Despite activation of the proapoptotic PERK branch of the unfolded protein response (UPR) and upregulation of TRAIL-R2, MCTSs are markedly more resistant to ER stress than 2D cultures of tumor cells. Resistance of MCTSs to ER stress-induced apoptosis correlates with sustained cFLIPL expression. Interestingly, resistance to ER stress-induced apoptosis is abolished in MCTSs generated from cFLIPL knockdown tumor cells. Overall, our results suggest that controlling cFLIP levels in tumors is an adaptive strategy to prevent tumor cell’s demise in the unfavorable conditions of the tumor microenvironment.

TFF1 in Aqueous Humor—A Potential New Biomarker for Retinoblastoma

Simple SummaryRetinoblastoma is the most common pediatric intraocular malignancy with high cure rates in developed countries. Nevertheless, useful predictive biomarkers providing reliable evidence for therapy decisions are urgently needed to optimize therapy regimes. TFF1 is a promising candidate as it is expressed in a more advanced subtype of retinoblastoma. Additionally, TFF1 is a naturally secreted peptide. Thus, TFF1 might be detectable in the aqueous humor of RB patients’ eyes, providing the opportunity to determine its expression prior to therapy without the necessity of a tumor biopsy. We therefore investigated for the first time aqueous humor samples of retinoblastoma patients in order to test for the availably and expression status of TFF1 as well as to compare it with the original tumor and established corresponding primary cell cultures.Retinoblastoma (RB) is the most common childhood eye cancer. The expression of trefoil factor family peptide 1 (TFF1), a small secreted peptide, has been correlated with more advanced RB stages and it might be a promising new candidate as a RB biomarker. The study presented addressed the question of if TFF1 is detectable in aqueous humor (AH) of RB patients’ eyes, providing easy accessibility as a diagnostic and/or therapy accompanying predictive biomarker. The TFF1 expression status of 15 retinoblastoma AH samples was investigated by ELISA and Western blot analyses. The results were correlated with the TFF1 expression status in the tumor of origin and compared to TFF1 expression in established corresponding primary tumor cell cultures and supernatants. Nine out of fifteen AH patient samples exhibited TFF1 expression, which correlated well with TFF1 levels of the original tumor. TFF1 expression in most of the corresponding primary cell cultures reflects the levels of the original tumor, although not all TFF1-expressing tumor cells seem to secret into the AH. Together, our findings strongly suggest TFF1 as a reliable new RB biomarker.

Self-Organization Formation of Multicellular Spheroids Mediated by Mechanically Tunable Hydrogel Platform: Toward Revealing the Synergy of Chemo- and Noninvasive Photothermal Therapy against Colon Microtumor.

Three-dimensional (3D) tumor cell culture offers a more tissue-recapitulating model in cancer treatment evaluation. However, conventional models based on cell-substrate adhesion deprivation are still of insufficient real tumor mimic. In this work, a novel method is proposed for inducing multicellular spheroids (MCSs) formation based on hydrogel with tunable microenvironmental properties. Colon tumor cells DLD1 cultured on hydrogel substrate with proper physical stimulation form MCSs via self-organization. Chemotherapy based on clinical drug and far-infrared photothermal therapy is evaluated with DLD1 MCSs obtained by this method. The synergism of chemotherapy and noninvasive photothermal therapy based on graphene device is further verified in MCSs model and it is believed this method holds potential in in vitro anti-tumor strategies evaluation for precision medicine.

Lung Adenocarcinoma Cells Promote Self-Migration and Self-Invasion by Activating Neutrophils to Upregulate Notch3 Expression of Cancer Cells.

Background: Invasion and migration of cancer cells play a key role in lung cancer progression and metastasis. Tumor-associated neutrophils (TANs) are related to poor prognosis in many types of cancer. However, the role of TANs in lung cancer is controversial. In this study, we investigated the effect of TANs on the invasion and migration of lung adenocarcinoma. Methods: Immunohistochemistry was performed to detect the density of infiltrating TANs and the expression of Notch3 in 100 lung adenocarcinoma tissues. Flow cytometry was used to observe the viability of neutrophils, which were isolated from healthy peripheral blood and then exposed to the supernatant of cultured lung adenocarcinoma cell lines. After treating with tumor-associated neutrophils culture supernatant, NeuCS (supernatant of cultured neutrophils), tumor cells culture supernatant, Medium (serum-free medium), respectively, the migration and invasion of the lung cancer cells before and after transfected by si-Notch3 were detected by transwell assay and wound healing assay. Kaplan-Meier plotter (http://kmplot.com/analysis/index.php?p) was used to analyze the prognostic role of the density of TANs on lung adenocarcinoma and TIMER ((http://cistrome.dfci.harvard.edu/TIMER/) was used to detect the expression of Notch3 on lung adenocarcinoma. Results: The infiltration of TANs was observed in the parenchyma and stroma of the lung adenocarcinoma, the density of TANs was positively related to the TNM stage and negatively related to the differentiation and prognosis. Notch3 expression of cancer cells was negatively related to the tumor differentiation and prognosis. Compared to quiescent neutrophils, the viability of TCCS-activated neutrophils was enhanced. Both migration and invasion of A549 and PC9 cells were significantly promoted by TANs, while after knocking down Notch3, the migration and invasion of the cancer cells were not affected by TANs. Bioinformatics analysis showed that the density of TANs and the expression of Notch3 were related to the poor prognosis. Conclusion: The results indicated that lung adenocarcinoma cells promote self-invasion and self-migration by activating neutrophils to upregulate the Notch3 expression of cancer cells. The density of infiltrating TANs may be a novel marker for the poor prognosis of lung adenocarcinoma. Targeting TANs might be a potential therapeutic strategy for lung cancer treatment.

Modulation of Biological Responses of Tumor Cells Adhered to Poly(2-methoxyethyl acrylate) with Increasing Cell Viability under Serum-Free Conditions.

Circulating tumor cells in body fluids are important biomarkers in cancer diagnosis. The culture of tumor cells isolated from body fluids can provide intrinsic information about tumors and can be used to screen for the best anticancer drugs. However, the culture of primary tumor cells has been hindered by their low viability and difficulties in recapitulating the phenotype of primary tumors in in vitro culture. The culture of tumor cells under serum-free conditions is one of the methodologies to maintain the phenotype and genotype of primary tumors. Poly(2-methoxyethyl acrylate) (PMEA)-coated substrates have been investigated to prolong the proliferation of tumor cells under serum-free conditions. In this study, we investigated the detailed behavior and the mechanism of the increase in tumor cell viability after adherence to PMEA substrates. The blebbing formation of tumor cells on PMEA was attributed not to apoptosis but to the low adhesion strength of cells on PMEA. Moreover, blebbing tumor cells showed amoeboid movement and formed clusters with other cells via N-cadherin, leading to an increase in tumor cell viability. Furthermore, the behaviors of tumor cells adhered to PMEA under serum-free conditions were involved in the activation of the PI3K and Rho-associated protein kinase pathways. Thus, we propose that PMEA would be suitable for the development of devices to cultivate primary tumor cells under serum-free conditions for the label-free diagnosis of cancer.

Isolation and Fluorescent Labeling of Extracellular Vesicles from Cultured Tumor Cells.

Extracellular vesicles (EVs), comprising exosomes, ectosomes, and apoptotic bodies, are an important component of molecular cell-to-cell communication, and are critically involved in the pathophysiology of various diseases, including tumors. In order to study the interaction of tumor cell-derived EVs with their target cells and to investigate their biological functions in comparison to other tumor cell-released factors, efficient isolation of EVs from cultured tumor cells, as well as fluorescent labeling of these EVs, is often necessary. In addition, EVs and EV-like particles are emerging as versatile vehicles for the delivery of therapeutic substances. Here, we describe an easy size exclusion chromatography-based method to isolate EVs from the mouse melanoma cell line B16F10 that yields highly enriched EV samples for subsequent applications such as molecular and functional studies. Our protocol also includes an optional labeling step with the lipophilic dye DiD, which allows tracking of EV uptake by recipient cells in vitro and in vivo.

3D Culture of Primary Patient-Derived Hepatoblastoma Tumoroids.

Hepatoblastoma, the most common primary liver malignancy in children, remains poorly understood due in part to a relative lack of methods to expand tumor cells in culture and a paucity of robust experimental models. Here, we describe a method to obtain primary tumor cells from patients with hepatoblastoma and to propagate the cells in 3D culture as tumor organoids, or "tumoroids". We further detail methods to prepare the tumoroids for whole-mount and cross-sectional imaging as well as to perform lentiviral transduction.

Optimization of Extracellular Flux Assay to Measure Respiration of Anchorage-independent Tumor Cell Spheroids.

Three-dimensional (3D) cell culture models are widely used in tumor studies to more accurately reflect cell-cell interactions and tumor growth conditions in vivo. 3D anchorage-independent spheroids derived by culturing cells in ultra-low attachment (ULA) conditions is particularly relevant to ovarian cancer, as such cell clusters are often observed in malignant ascites of late-stage ovarian cancer patients. We and others have found that cells derived from anchorage-independent spheroids vary widely in gene expression profiles, proliferative state, and metabolism compared to cells maintained under attached culture conditions. This includes changes in mitochondrial function, which is most commonly assessed in cultured live cells by measuring oxygen consumption in extracellular flux assays. To measure mitochondrial function in anchorage-independent multicellular aggregates, we have adapted the Agilent Seahorse extracellular flux assay to optimize measurements of oxygen consumption and extracellular acidification of ovarian cancer cell spheroids generated by culture in ULA plates. This protocol includes: (i) Methods for culturing tumor cells as uniform anchorage-independent spheroids; (ii) Optimization for the transfer of spheroids to the Agilent Seahorse cell culture plates; (iii) Adaptations of the mitochondrial and glycolysis stress tests for spheroid extracellular flux analysis; and (iv) Suggestions for optimization of cell numbers, spheroid size, and normalization of oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) values. Using this method, we have found that ovarian cancer cells cultured as anchorage-independent spheroids display altered mitochondrial function compared to monolayer cultures attached to plastic dishes. This method allows for the assessment of mitochondrial function in a more relevant patho/physiological culture condition and can be adapted to evaluate mitochondrial function of various cell types that are able to aggregate into multicellular clusters in anchorage-independence. Graphic abstract: Workflow of the Extracellular Flux Assay to Measure Respiration of Anchorage-independent Tumor Cell Spheroids.

Process simplification and structure design of parallelized microslit isolator for physical property-based capture of tumor cells.

Numerous attempts have been made to develop efficient systems to purify trace amounts of circulating tumor cells (CTCs) from blood samples. However, current technologies are limited by complexities in device fabrication, system design, and process operability. Here we describe a facile, scalable, and highly efficient approach to physically capturing CTCs using a rationally designed microfluidic isolator with an array of microslit channels. The wide but thin microslit channels with a depth of several micrometers selectively capture CTCs, which are larger and less deformable than other blood cells, while allowing other blood cells to just flow through. We investigated in detail the effects of the microchannel geometry and operating parameters on the capture efficiency and selectivity of several types of cultured tumor cells spiked in blood samples as the CTC model. Additionally, in situ post-capture staining of the captured cells was demonstrated to investigate the system's applicability to clinical cancer diagnosis. The presented approach is simple in operation but significantly effective in capturing specific cells and hence it may have great potential in implementating cell physics-based CTC isolation techniques for cancer liquid biopsy.

Assessment of the effectiveness of the use of tumoroids for personalized drug therapies for solid tumors

The approach to the management of cancerous neoplasms, which aims to define the effective curative strategies in each patient, defines the requirement for the elaboration and use of modelling systems that replicate the structures and the biology of human solitary tumors. Three-dimensional cultures of spheroids/tumoroids, which are multi-cell aggregates of malignized cells, can create the intercellular connections of interest, gradients of the nutrients and oxygen, and cell polarity, all of which are absent in the conventional two-dimensional single-layer system. The present work is dedicated to a comparison study of in vitro viability and invasiveness of solid tumor cells of patients under the effect of chemopreparations and their combinations in view of evaluating the efficacy of the 3D-cell modelling system in the translational personalized medicine context. Cell cultures of patients who were treated at the N.N. Petrov National Medicine Research Center of oncology were used as a basis for the development of 3D-cell models. N.N. Petrov NMRC in 2015-2021. Tumor tissue pieces were acquired intraoperatively: 1 - leiomyosarcoma (LMS), 1 - rhabdomyosarcoma (RMS), 1 - synovial sarcoma (SS), 2 - myxofibrosarcoma (MFS), 2 - osteogenic sarcoma (OS), 1 - skin melanoma (MC), 1 - breast cancer (BC) (n=9). Our individual comparison of the effectiveness of in vitro chemotherapeutic agents against tumor cells of various origins cultivated in 2D and 3D model systems with real clinically relevant cases confirmed that the monolayer culture as the test system was less adequate for selecting and personalizing the treatment of malignant tumor patients: the 3D cell system proved itself in 77.7% of cases, and the monolayer culture - in 44.4% of cases. The combination of doxorubicin/iforsfamide and paclitaxel significantly suppressed the motility in the matrigel of spheroid cells, but did not affect tumor cell viability, which was seen in all but OS #921 and MK #929 cases. The cultivation of tumor cells in form of spheroids/tumoroids allows to utilize them as more adequate pre-clinical model as individual predictive test-system, enabling the personalized selection of therapy.

Antiadhesive nanosome elicits role of glycocalyx of tumor cell-derived exosomes in the organotropic cancer metastasis

Despite emerging importance of tumor cells-derived exosomes in cancer metastasis, the heterogeneity of exosome populations has largely hampered systemic characterization of their molecular composition, biogenesis, and functions. This study communicates a novel method for predicting and targeting pre-metastatic sites based on an exosome model “fluorescent cancer glyconanosomes” displaying N-glycans of cultured tumor cells. Glycoblotting by antiadhesive quantum dots provides a nice tool to shed light on the pivotal functions of the glycocalyx reconstructed from four cancer cell types without bias due to other compositions of exosomes. In vivo imaging revealed that circulation, clearance, and organotropic biodistribution of cancer glyconanosomes in mice depend strongly on cancer cell-type-specific N-glycosylation patterns, the compositions of key glycotypes, particularly dominant abundances of high mannose-type N-glycans and the position-specific sialylation. Notably, organ biodistribution of cancer glyconanosomes is reproducible artificially by mimicking cancer cell-type-specific N-glycosylation patterns, demonstrating that nanosomal glycoblotting method serves as promising tools for predicting and targeting pre-metastatic sites determined by the glycocalyx of extracellular vesicles disseminated from the primary cancer site.

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.

Cytological evaluation of a single cell culture of Luminal A subtype breast carcinoma cells

Introduction. Despite significant advances in the creation of stable cell lines, the focus of research has recently shifted toward the creation of primary cell cultures derived directly from patient tumor samples, which include both tumor cells and microenvironmental cells.The aim of the study was to compare the morphological characteristics of the cells of a breast carcinoma sample when cultured over three passages.Materials and methods. Material for the study was obtained during surgical intervention in a patient diagnosed with breast carcinoma. Slices were prepared from the tumor sample according to the standard histological protocol and stained with monoclonal antibodies to estrogen, progesterone, Ki-67, Her2/neu receptors. Cell nuclei were stained with hematoxylin. Immunohistochemical reaction was performed in DAKO autostainer (Denmark). Part of the material was placed in Hanks' solution with 5% antibiotic antimycotics and delivered to the Cell Culture Laboratory, where after performing the standard protocol for obtaining cell culture, tumor cells were diluted in Mammocult nutrient medium and placed in culture vials. For morphological evaluation, cells were stained by Pappenheim. For immunocytochemical analysis in determining the belonging of cells to epithelial cells using anti-Pan Keratin Primary Antibody antibody. The number of cells was counted in an automatic TC20 counter, and culture growth was monitored using an Eclipse TS100 microscope, Nikon (Japan).Results and Discussion. On the basis of immunohistochemical study, the tumor sample was classified as Luminal-A subtype. During the study several groups of cells were isolated and cytologically evaluated. The results of immunocytochemical analysis of the cultured cells confirm that the tumor cells retained their epithelial phenotype during culturing. In spite of the manifestation of cell polymorphism in BML cell culture, during three passages the cultured tumor cells retained their epithelial nature and showed a tendency to form a monolayer.Conclusion. A detailed study of cytomorphology and immunocytological characteristics of cultured cells of different immunohistochemical PBMC subtypes will help to evaluate the main regularities of tumor cell vital functions in vitro and allow a more differentiated approach to the creation of personalized cell cultures in order to develop a targeted chemotherapeutic effect on tumors of specific patients.

The Extracellular Matrix Environment of Clear Cell Renal Cell Carcinoma Determines Cancer Associated Fibroblast Growth.

Simple SummaryClear cell renal cell carcinoma (ccRCC) is the most common kidney cancer. Cell culture studies have the potential to explain how interactions between cancer cells and their support cells (stroma) determine growth and malignancy of ccRCC. The ability to grow tumor cells together with stroma from patient tumors is critical for studies of these interactions, but conventional culture methods do not provide representation of both cell types. We hypothesized that mimicking the extracellular environment of the tumor would promote growth of both tumor and stromal cells. We characterized the extracellular protein composition of patient ccRCCs and defined a nine-component protein blend to mimic the tumor microenvironment. Adherence of tumor cells, supporting stromal cells, and immune cells was demonstrated. Furthermore, we found that cells from patient tumors grown in our protein blend maintained representation of both tumor cells and cancer-associated fibroblasts (CAFs), a stromal cell type that plays a defining but poorly understood role in establishing the tumor microenvironment. This study demonstrates the dependence of CAFs on the extracellular protein composition and provides a technology to investigate interactions between tumor cells and CAFs isolated from patient ccRCCs.Clear cell renal cell carcinoma (ccRCC) is the most common kidney cancer and is often caused by mutations in the oxygen-sensing machinery of kidney epithelial cells. Due to its pseudo-hypoxic state, ccRCC recruits extensive vasculature and other stromal components. Conventional cell culture methods provide poor representation of stromal cell types in primary cultures of ccRCC, and we hypothesized that mimicking the extracellular environment of the tumor would promote growth of both tumor and stromal cells. We employed proteomics to identify the components of ccRCC extracellular matrix (ECM) and found that in contrast to healthy kidney cortex, laminin, collagen IV, and entactin/nidogen are minor contributors. Instead, the ccRCC ECM is composed largely of collagen VI, fibronectin, and tenascin C. Analysis of single cell expression data indicates that cancer-associated fibroblasts are a major source of tumor ECM production. Tumor cells as well as stromal cells bind efficiently to a nine-component ECM blend characteristic of ccRCC. Primary patient-derived tumor cells bind the nine-component blend efficiently, allowing to us to establish mixed primary cultures of tumor cells and stromal cells. These miniature patient-specific replicas are conducive to microscopy and can be used to analyze interactions between cells in a model tumor microenvironment.

EXTH-10. EXPLORATION OF A NOVEL TOXIN-INCORPORATING CAR T CELL: HOW DOES CHLOROTOXIN RECOGNIZE GLIOBLASTOMA CELLS?

Abstract Chlorotoxin, a peptide toxin component of scorpion venom, binds selectively to glioblastoma and other neuroepithelial tumors, with minimal binding to non-malignant cells. We have recently developed a CAR T cell incorporating chlorotoxin (CLTX) as its target recognition domain, and CLTX-CAR T cells are now in clinical trial for recurrent glioblastoma (NCT04214392). We determined in preclinical studies that surface MMP-2 was required for CLTX-CAR T cell killing. However, the precise composition and structure of the cell surface complex recognized by CLTX-CAR T cells remains an unresolved question of increasing importance. Previous investigations have variously proposed matrix metalloprotease-2 (MMP-2), ClC-3 chloride channels, regulators of MMP-2, annexin A2, and neuropilin-1, as receptors, or components of receptors, for CLTX. To approach this question, we have visualized bound Cy5.5-conjugated CLTX peptide (CLTX.Cy5.5) or biotin-conjugated CLTX peptide (CLTX.biotin) on tumor cells in fixed sections of patient resections, on tumor cells in organotypic cultures of patient resections, and on cells of cultured patient-derived glioblastoma tumor lines. At tissue- and cell-level spatial resolution, we saw good correlation of CLTX binding with MMP-2 expression in patient tumor samples and on cultured GBM cells, and between CLTX binding and tumor cell death (cleaved caspase-3) in organotypic GBM cultures. However, at subcellular resolution, surface binding of CLTX was related to, but not precisely overlapping, with MMP-2 or other putative receptors. Rather, on fixed PBT003, PBT030 and PBT106 cells in monolayer cultures, MMP-2 staining was clustered, with diffuse loosely associated CLTX.biotin staining. Diffuse distribution of CLTX.Cy5.5 was also seen in fixed xenograft sections of PBT003-4, PBT1206, PBT030-2, PBT051 and PBT138 tumor cells, and not obviously associated with more discrete staining for IL13Rα2 and EGFR. Ongoing experiments are further examining association of CLTX with other putative components of CLTX receptor complexes, and their redistribution during binding by CLTX and CLTX-CAR T cells.