Establishment and characterization of a novel multidrug-resistant pancreatic ductal adenocarcinoma cell line, PDAC-X1.

Drug resistance remains a significant challenge in the treatment of pancreatic cancer. The development of drug-resistant cell lines is crucial to understanding the underlying mechanisms of resistance and developing novel drugs to improve clinical outcomes. Here, a novel pancreatic cancer cell line, PDAC-X1, derived from Chinese patients has been established. PDAC-X1 was characterized by the immune phenotype, biology, genetics, molecular characteristics, and tumorigenicity. In vitro analysis revealed that PDAC-X1 cells exhibited epithelial morphology and cell markers (CK7 and CK19), expressed cancer-associated markers (E-cadherin, Vimentin, Ki-67, CEA, CA19-9), and produced pancreatic cancer-like organs in suspension culture. In vivo analysis showed that PDAC-X1 cells maintained tumorigenicity with a 100% tumor formation rate. This cell line exhibited a complex karyotype, dominated by subtriploid karyotypes. In addition, PDAC-X1 cells exhibited intrinsic multidrug resistance to multiple drugs, including gemcitabine, paclitaxel, 5-fluorouracil, and oxaliplatin. In conclusion, the PDAC-X1 cell line has been established and characterized, representing a useful and valuable preclinical model to study the underlying mechanisms of drug resistance and develop novel drug therapeutics to improve patient outcomes.

Nanoparticles with a Lipid Core Can Enhance the Infection of Epithelial Cells with an Enterovirus.

INTRODUCTION: The effect of maltodextrin-based nanoparticles with an anionic phospholipid core (lipid-based nanoparticles [NPLs]) on the infection of a human tumoral cell line with poliovirus (PV) has been studied. METHODS: NPLs were synthesized and associated with the PV type 1 Sabin strain, and the formulations were characterized. PV and PV/NPL formulations were inoculated to HEp-2 cells. RESULTS: The surface charge and the diameter of PV/NPL formulation suggest that viral particles were adsorbed onto NPLs. When HEp-2 cells were inoculated with 1 tissue culture 50% infectious dose/mL PV associated with NPLs, the cytopathic effect appeared obvious; the levels of the infectious titer of culture supernatants and the proportion of VP1-positive cells were higher. The level of intracellular viral RNA extracted from HEp-2 cells inoculated with PV/NPL formulation was higher as well. CONCLUSION: These results show that NPLs can enhance the infection with a virus and suggest that they might be used in virotherapy to increase the virus-mediated lysis of tumor cells.

Glioblastoma Extracellular Vesicle-Specific Peptides Inhibit EV-Induced Neuronal Cytotoxicity.

WHO Grade 4 IDH-wild type astrocytoma (GBM) is the deadliest brain tumor with a poor prognosis. Meningioma (MMA) is a more common "benign" central nervous system tumor but with significant recurrence rates. There is an urgent need for brain tumor biomarkers for early diagnosis and effective treatment options. Extracellular vesicles (EVs) are tiny membrane-enclosed vesicles that play essential functions in cell-to-cell communications among tumor cells. We aimed to identify epitopes of brain tumor EVs by phage peptide libraries. EVs from GBM plasma, MMA plasma, or brain tumor cell lines were used to screen phage-displayed random peptide libraries to identify high-affinity peptides. We purified EVs from three GBM plasma pools (23 patients), one MMA pool (10 patients), and four brain tumor cell lines. We identified a total of 21 high-affinity phage peptides (12 unique) specific to brain tumor EVs. The peptides shared high sequence homologies among those selected by the same EVs. Dose-response ELISA demonstrated that phage peptides were specific to brain tumor EVs compared to controls. Peptide affinity purification identified unique brain tumor EV subpopulations. Significantly, GBM EV peptides inhibit brain tumor EV-induced complement-dependent cytotoxicity (necrosis) in neurons. We conclude that phage display technology could identify specific peptides to isolate and characterize tumor EVs.

Antitumor Effects of 5-Aminolevulinic Acid on Human Malignant Glioblastoma Cells.

5-Aminolevulinic acid (5-ALA) is a naturally occurring non-proteinogenic amino acid, which contributes to the diagnosis and therapeutic approaches of various cancers, including glioblastoma (GBM). In the present study, we aimed to investigate whether 5-ALA exerted cytotoxic effects on GBM cells. We assessed cell viability, apoptosis rate, mRNA expressions of various apoptosis-related genes, generation of reactive oxygen species (ROS), and migration ability of the human U-87 malignant GBM cell line (U87MG) treated with 5-ALA at different doses. The half-maximal inhibitory concentration of 5-ALA on U87MG cells was 500 µg/mL after 7 days; 5-ALA was not toxic for human optic cells and NIH-3T3 cells at this concentration. The application of 5-ALA led to a significant increase in apoptotic cells, enhancement of Bax and p53 expressions, reduction in Bcl-2 expression, and an increase in ROS generation. Furthermore, the application of 5-ALA increased the accumulation of U87MG cells in the SUB-G1 population, decreased the expression of cyclin D1, and reduced the migration ability of U87MG cells. Our data indicate the potential cytotoxic effects of 5-ALA on U87MG cells. Further studies are required to determine the spectrum of the antitumor activity of 5-ALA on GBM.

Cytotoxic Activity of Origanum Vulgare L. on Hepatocellular Carcinoma cell Line HepG2 and Evaluation of its Biological Activity.

The potential of plant essential oils (EOs) in anticancer treatment has recently received many research efforts to overcome the development of multidrug resistance and their negative side effects. The aims of the current research are to study (i) the cytotoxic effect of the crude EO extracted from Origanum vulgare subsp hirtum and its main constituents (carvacrol, thymol, citral and limonene) on hepatocarcinoma HepG2 and healthy human renal cells HEK293; (ii) the antibacterial and phytotoxic activities of the above EO and its main constituents. Results showed that cell viability percentage of treated HepG2 by EO and its main constituents was significantly decreased when compared to untreated cells. The calculated inhibition concentration (IC50) values for HepG2 were lower than healthy renal cells, indicating the sort of selectivity of the studied substances. Citral is not potentially recommended as an anticancer therapeutic agent, since there are no significant differences between IC50 values against both tested cell lines. Results showed also that oregano EO and its main constituents have a significant antibacterial activity and a moderate phytotoxic effect. The current research verified that oregano EO and its main constituents could be potentially utilized as anticancer therapeutic agents.

Detection for cross-reactive proteins in filarial worm Setaria equina, MCF-7 human breast cancer, and Huh-7 hepatoma cells.

This study aimed to detect the cross-reactive proteins in filarial parasite adult worm Setaria equina and two different tumor cell lines (MCF-7 human breast cancer and Huh-7 hepatoma cells). This was performed using rabbit anti-S. equina extract (SeqE) or DEC (Diethylcarbamazine citrate) polyclonal IgG antibodies by indirect ELISA and western blotting. The results indicated cross-reactive bands at 70 and 75 kDa in all extracts by anti-DEC and SeqE antibodies, respectively. In addition, the expression of 70 kDa protein was only reduced in filarial worms and Huh-7 after in vitro DEC treatment compared to the control.

An Aqueous Extract of Tuberaria lignosa Inhibits Cell Growth, Alters the Cell Cycle Profile, and Induces Apoptosis of NCI-H460 Tumor Cells.

Tuberaria lignosa (Sweet) Samp. is found in European regions, and has antioxidant properties due to its composition in ascorbic acid and phenolic compounds. Given its traditional use and antioxidant properties, the tumor cell growth inhibitory potential of aqueous extracts from T. lignosa (prepared by infusion and decoction) was investigated in three human tumor cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and HCT-15 (human colorectal adenocarcinoma). Both extracts inhibited the growth of these cell lines; the most potent one being the T. lignosa extract obtained by infusion in the NCI-H460 cells (GI50 of approximately 50 µg/mL). Further assays were carried out with this extract in NCI-H460 cells. At 100 µg/mL or 150 µg/mL it caused an increase in the percentage of cells in the G0/G1 phase and a decrease of cells in S phase of the cell cycle. Additionally, these concentrations caused an increase in the percentage of apoptotic cells. In agreement, a decrease in total poly (ADP-ribose) polymerase (PARP) and pro-caspase 3 levels was found. In conclusion, the T. lignosa extract obtained by infusion was more potent in NCI-H460 cells, altering the cell cycle progression and inducing apoptosis. This work highlights the importance of T. lignosa as a source of bioactive compounds with tumor cell growth inhibitory potential.

The Mucus of Actinia equina (Anthozoa, Cnidaria): An Unexplored Resource for Potential Applicative Purposes.

The mucus produced by many marine organisms is a complex mixture of proteins and polysaccharides forming a weak watery gel. It is essential for vital processes including locomotion, navigation, structural support, heterotrophic feeding and defence against a multitude of environmental stresses, predators, parasites, and pathogens. In the present study we focused on mucus produced by a benthic cnidarian, the sea anemone Actinia equina (Linnaeus, 1758) for preventing burial by excess sedimentation and for protection. We investigated some of the physico-chemical properties of this matrix such as viscosity, osmolarity, electrical conductivity, protein, carbohydrate, and total lipid contents. Some biological activities such as hemolytic, cytotoxic, and antibacterial lysozyme-like activities were also studied. The A. equina mucus is mainly composed by water (96.2% ± 0.3%), whereas its dry weight is made of 24.2% ± 1.3% proteins and 7.8% ± 0.2% carbohydrates, with the smallest and largest components referable to lipids (0.9%) and inorganic matter (67.1%). The A. equina mucus matrix exhibited hemolytic activity on rabbit erythrocytes, cytotoxic activity against the tumor cell line K562 (human erythromyeloblastoid leukemia) and antibacterial lysozyme-like activity. The findings from this study improve the available information on the mucus composition in invertebrates and have implications for future investigations related to exploitation of A. equina and other sea anemones' mucus as a source of bioactive compounds of high pharmaceutical and biotechnological interest.

Orthotopic Wilms tumor xenografts derived from cell lines reflect limited aspects of tumor morphology and clinical characteristics.

BACKGROUND: Wilms tumor (WT) is a pediatric tumor of the kidney, the treatment of which includes heavy chemotherapy. Affected children would likely benefit from more targeted therapies with limited side effects. Establishment of relevant orthotopic WT xenografts is important to better understand mechanisms of WT growth and for preclinical drug testing. PROCEDURE: Here we established and characterized orthotopic xenografts from WT cell lines WiT49, CCG-99-11, and WT-CLS1 to ascertain in what aspects each of them recapitulated WT histology, immunophenotype, invasion, and metastatic spread. RESULTS: WiT49 xenografts recapitulated near triphasic WTs with clear WT1 staining and anaplastic features, but with tumor restricted to the kidney. On the contrary both CCG-99-11 and WT-CLS1 xenografts conveyed metastatic disease. CCG-99-11 showed a blastemal phenotype whereas WT-CLS1 xenografts did not properly reflect any specific WT subtype. CONCLUSIONS: From the three tested cell lines, orthotopic WiT49 xenografts best reflect the triphasic pattern of classical WT.

Synthesis of Gingerol-Metals Complex and in-vitro Cytotoxic Activity on Human Colon Cancer Cell Line.

Introduction: Herbs are excellent sources of medicinal substances, and their curative abilities have been recognized to treat many ailments and are used for example as antioxidants, analgesics, anti-inflammatories, antipyretics, and many other medicinal uses. The properties of natural compounds and their health effects have been studied extensively, especially those that originate from plant sources such as ginger. The ginger plant contains many chemical compounds, such as 6-gingerol, which is characterized by containing active groups such as carbonyl and hydroxide, which can be attached to metal molecules. This is what was done in this study, where the formation of complexes with a group of metals was studied and their effect on cancer cells was investigated. These complexes will open new horizons for further study of medicinal uses. Methods: The synthesis of gingerol-metal complexes was carried out by conjugating gingerol molecules with Ag, Au, Cd, Co, Cu, Ni, and Zn metal ions. The extracted gingerol was transferred to culture tubes and deionized water-DMSO were added followed by sonication. The tubes were incubated at 90°C for two days as well as the control sample. The samples were then filtered and the complex solutions were transferred into new tubes for further studies. Different characterization techniques such as FT-IR, UV-vis spectroscopy, FESEM, and EDX are used to confirm the formation of the complexes. The in vitro of the complexes was tested by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay against the human colorectal cancer cell lines HCT116 and HT29 which exhibited strong cytotoxicity. Results: The gingerol-metal complexes showed an enhancement as an anticancer agent compared to the control. The in vitro anticancer activity showed that the Ag-gingerol complex showed the most activity among the other complexes. Discussion: Gingerol-metal complexes can inhibit cancer cells, noting that the potency of the complex depends on the type of metal used.

Antioxidant and Antitumor Potential of Micropropagated Balkan Endemic Sideritis scardica Griseb.

Sideritis scardica Griseb. is a critically endangered Balkan endemic species, known for its antioxidant, neuroprotective and anti-inflammatory properties. The aim of the present study was to detail an efficient protocol for the micropropagation of S. scardica. In vitro cultures were initiated from the shoot tips of 40 days-old in vivo seedlings and the effects of different plant growth regulator treatments were examined. A Murashige and Skoog nutrient medium (MS) containing 1 mg/L zeatin and 0.1 mg/L indole-3-acetic acid (IAA) proved to be the most efficient for shoot multiplication as it produced quality, vigorous shoots with a mean number of six shoots per explant. For the first time, the antioxidant and antitumor activities of extracts from in vitro-obtained plants were evaluated. In vitro cultivated plants grown in the field revealed a higher total polyphenol content (3929.1 ± 112.2 mg GAE/100 g vs. 3563.5 ± 52.8 mg GAE/100 g) and higher ORAC antioxidant activity (1211.6 ± 27.3 µmol TE/g vs. 939.9 ± 52.4 µmol TE/g) than in situ cultivated plants. A comparison of the antitumor activities of extracts from in vitro propagated shoots, field-grown in vitro-obtained plants and in situ plants on HeLa (cervical adenocarcinoma), HT-29 (colorectal adenocarcinoma) and MCF-7 (breast cancer) human cancer cell lines showed that in vitro propagated shoots had a significant concentration-dependent cytotoxic effect on the cervical adenocarcinoma cell line HeLa, while the field-grown in vitro-obtained and in situ-collected samples induced the highest reduction in the viability of the mammary carcinoma cell line MCF-7. In both cases, the cells of the control non-tumor cell line, BALB/3T3, were significantly less affected. The results showed that the in vitro multiplication protocol ensured the obtainment of numerous plants with antioxidant and antitumor potential.

Corrigendum: Arachidonic acid in follicular fluid of PCOS induces oxidative stress in a human ovarian granulosa tumor cell line (KGN) and upregulates GDF15 expression as a response.

[This corrects the article DOI: 10.3389/fendo.2022.865748.].

New Ameloblastoma Cell Lines Enable Preclinical Study of Targeted Therapies.

Ameloblastoma (AB) is an odontogenic tumor that arises from ameloblast-lineage cells. Although relatively uncommon and rarely metastatic, AB tumors are locally invasive and destructive to the jawbone and surrounding structures. Standard-of-care surgical resection often leads to disfigurement, and many tumors will locally recur, necessitating increasingly challenging surgeries. Recent genomic studies of AB have uncovered oncogenic driver mutations, including in the mitogen-activated protein kinase (MAPK) and Hedgehog signaling pathways. Medical therapies targeting those drivers would be a highly desirable alternative or addition to surgery; however, a paucity of existing AB cell lines has stymied clinical translation. To bridge this gap, here we report the establishment of 6 new AB cell lines-generated by "conditional reprogramming"-and their genomic characterization that reveals driver mutations in FGFR2, KRAS, NRAS, BRAF, PIK3CA, and SMO. Furthermore, in proof-of-principle studies, we use the new cell lines to investigate AB oncogene dependency and drug sensitivity. Among our findings, AB cells with KRAS or NRAS mutation (MAPK pathway) are exquisitely sensitive to MEK inhibition, which propels ameloblast differentiation. AB cells with activating SMO-L412F mutation (Hedgehog pathway) are insensitive to vismodegib; however, a distinct small-molecule SMO inhibitor, BMS-833923, significantly reduces both downstream Hedgehog signaling and tumor cell viability. The novel cell line resource enables preclinical studies and promises to speed the translation of new molecularly targeted therapies for the management of ameloblastoma and related odontogenic neoplasms.

[Retracted] The Fanconi anemia pathway sensitizes to DNA alkylating agents by inducing JNK­p53­dependent mitochondrial apoptosis in breast cancer cells.

Following the publication of the above paper, a concerned reader drew to the Editor's attention that one of the fluorescence microscopic images featured in Fig. 4A had previously appeared in a different form (a portion of data in a different orientation) in another article published by the same authors [Yu J, Zhao L, Li Y, Li N, He M, Bai H, Yu Z, Zheng Z, Mi X, Wang E and We M: Silencing of Fanconi anemia complementation group F exhibits potent chemosensitization of mitomycin C activity in breast cancer cells. J Breast Cancer 16: 291­299, 2013]. Furthermore, the data panel shown for the 'MDA­MB­231/untreated' experiment in Fig. 4A in the above paper appeared to be duplicated as the 'MDA­MB­231/MMC + control shRNA' experiment, albeit stained differently. After having received a request from the authors to publish a corrigendum in view of the errors identified in Fig. 4 of the above paper, the Editor of International Journal of Oncology has conducted an independent investigation of the matter and determined that this article should be retracted from the Journal on account of a lack of confidence in the presented data. Upon receiving this decision, the authors were not in agreement that the paper should be retracted. The Editor regrets any inconvenience that has been caused to the readership of the Journal. [the original article was published in International Journal of Oncology 45: 129­138, 2014; DOI: 10.3892/ijo.2014.2400].

Arachidonic Acid in Follicular Fluid of PCOS Induces Oxidative Stress in a Human Ovarian Granulosa Tumor Cell Line (KGN) and Upregulates GDF15 Expression as a Response.

Polycystic ovarian ovary syndrome (PCOS) is the main cause of ovulatory infertility and a common reproductive endocrine disease of women in reproductive age. In addition, nearly half of PCOS patients are associated with obesity, and their total free fatty acids tend to increase. Arachidonic acid (AA) is a polyunsaturated fatty acid. Oxidation products of AA reacting with various enzymes[cyclooxygenases (COX), lipoxygenases (LOX), cytochrome P450s (CYP)] can change cellular mitochondrial distribution and calcium ion concentration, and increase reactive oxygen species (ROS) production. In this study, we analyzed the follicular fluid fatty acids and found higher levels of C20:4n6 (AA) in PCOS patients than in normal control subjects. Also, to determine whether AA induces oxidative stress (OS) in the human ovarian granulosa tumor cell line (KGN) and affects its function, we treated KGN cells with or without reduced glutathione (GSH) and then stimulated them with AA. The results showed that AA significantly reduced the total antioxidant capacity (TAC) and activity of antioxidant enzymes and increased the malondialdehyde (MDA), ROS and superoxide anion(O2-)levels in KGN cells. In addition, AA was also found to impair the secretory and mitochondrial functions of KGN cells and induce their apoptosis. We further investigated the downstream genes affected by AA in KGN cells and its mechanism of action. We found that AA upregulated the expression of growth differentiation factor 15 (GDF15), which had a protective effect on inflammation and tissue damage. Therefore, we investigated whether AA-induced OS in KGN cells upregulates GDF15 expression as an OS response.Through silencing of GDF15 and supplementation with recombinant GDF15 (rGDF15), we found that GDF15, expressed as an OS response, protected KGN cells against AA-induced OS effects, such as impairment of secretory and mitochondrial functions and apoptosis. Therefore, this study suggested that AA might induce OS in KGN cells and upregulate the expression of GDF15 as a response to OS.

Evaluation of Usnea barbata (L.) Weber ex F.H. Wigg Extract in Canola Oil Loaded in Bioadhesive Oral Films for Potential Applications in Oral Cavity Infections and Malignancy.

Usnea lichens are known for their beneficial pharmacological effects with potential applications in oral medicine. This study aims to investigate the extract of Usnea barbata (L.) Weber ex F.H. Wigg from the Calimani Mountains in canola oil as an oral pharmaceutical formulation. In the present work, bioadhesive oral films (F-UBO) with U. barbata extract in canola oil (UBO) were formulated, characterized, and evaluated, evidencing their pharmacological potential. The UBO-loaded films were analyzed using standard methods regarding physicochemical and pharmacotechnical characteristics to verify their suitability for topical administration on the oral mucosa. F-UBO suitability confirmation allowed for the investigation of antimicrobial and anticancer potential. The antimicrobial properties against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27353, Candida albicans ATCC 10231, and Candida parapsilosis ATCC 22019 were evaluated by a resazurin-based 96-well plate microdilution method. The brine shrimp lethality assay (BSL assay) was the animal model cytotoxicity prescreen, followed by flow cytometry analyses on normal blood cells and oral epithelial squamous cell carcinoma CLS-354 cell line, determining cellular apoptosis, caspase-3/7 activity, nuclear condensation and lysosomal activity, oxidative stress, cell cycle, and cell proliferation. The results indicate that a UBO-loaded bioadhesive film's weight is 63 ± 1.79 mg. It contains 315 µg UBO, has a pH = 6.97 ± 0.01, a disintegration time of 124 ± 3.67 s, and a bioadhesion time of 86 ± 4.12 min, being suitable for topical administration on the oral mucosa. F-UBO showed moderate dose-dependent inhibitory effects on the growth of both bacterial and fungal strains. Moreover, in CLS-354 tumor cells, F-UBO increased oxidative stress, diminished DNA synthesis, and induced cell cycle arrest in G0/G1. All these properties led to considering UBO-loaded bioadhesive oral films as a suitable phytotherapeutic formulation with potential application in oral infections and neoplasia.

Bcl2-dependent antineoplastic effects of Calotropis procera root extract against canine mammary tumor cells.

There has been a prevailing trend in the application of herbal medicine as cancer therapeutics. Calotropis procera is an ayurvedic plant applied to ameliorate various illnesses. There is no report on the anti-tumor effects of the root of the plant on canine tumors, although it has been used for the treatment of various diseases in human medicine. The objective of the present study was to investigate the antitumor potential of ethanolic root extract of C. procera against canine mammary tumor cell line (CF41-Mg). MTT, western blot, and flow cytometry assays were carried out to evaluate the possible cytotoxicity and apoptosis induction of the extract. MTT results showed that the extract had a potent cytotoxic activity in a dose-dependent manner with an IC50 of 9.00 µg mL-1. Based on the results of flow cytometry and western blotting, IC50 concentration of the extract induced significant apoptosis in the studied cell line, possibly through down-regulation of Bcl-2 expression. The results of the present study clearly indicated that the root extract of C. procera had promising anti-cancer activity and could be considered as a candidate for the treatment of mammary tumors.

Evaluation of Real-Time In Vitro Invasive Phenotypes.

The methods described here provide a standardized process for assessing in vitro tumor cell migration and invasion in real time. The kinetic data generated under these standardized conditions are reproducible and characteristic of individual tumor cell lines. The complex kinetic features of the data can be analyzed using parameters modeled after pharmacokinetic data processing. Application of the method to the array of tumor types included in the National Cancer Institute's sixty cell line panel (NCI60) revealed distinct modes of invasion with some tumor cell lines utilizing a mesenchymal mode and generating information-rich kinetic profiles. Other cell lines utilized an amoeboid mode not suitable for detection with this method. The method described will be useful as a guide for tumor cell line selection and as a starting point in designing experiments probing migration and invasion.

Radachlorin-Containing Microparticles for Photodynamic Therapy.

Purpose: Reducing the undesirable systemic effect of photodynamic therapy (PDT) can be achieved by incorporating a photosensitizer in microparticles (MPs). This study is devoted to the preparation of biocompatible biodegradable MPs with the inclusion of the natural photosensitizer Radachlorin (RС) and an assessment of the possibility of their use for PDT. Methods: RC-containing MPs (RС MPs) with poly(lactic-co-glycolic acid) copolymer (PLGA) matrix were prepared by a double emulsion solvent evaporation methods. The size and morphology of RC MPs were surveyed using scanning electron microscopy, confocal laser scanning microscopy, and dynamic light scattering. The content of RC, its release from RC MPs, and singlet oxygen generation were evaluated by the optical spectroscopy. Cellular uptake and cytotoxic photodynamic effect of RC MPs were investigated with in vitro assays. Results: The average diameter of the prepared RC MPs was about 2-3 µm. The RC MPs prepared by the water/oil/oil method had a significantly higher inclusion of RC (1.74 µg/mg) then RC MPs prepared by the water/oil/water method (0.089 µg/mg). Exposure of the prepared RC MPs to PDT light radiation was accompanied by the singlet oxygen generation and a cytotoxic effect for tumor cells. The release of the RC from the RC MPs was prolonged and lasted at least two weeks. Conclusion: PLGA RC MPs were found to cause a photoactivated cytotoxic effect for tumor cells and can be used for local application in PDT of tumors.

Generation of affinity ranged antigen-expressing tumor cell lines.

The interaction strength between CD8+ T cells' TCR and cognate peptide-MHC (pMHC) impacts on the CD8+ T cell response against pathogens and tumors (Martinez-Usatorre, Donda, Zehn, & Romero, 2018; Zehn, Lee, & Bevan, 2009). CD8+ T cell responses against tumors are characterized by the presence of low affinity CD8+ T cells specific for nonmutated tumor associated self-antigens (TAA) and potentially high affinity tumor specific CD8+ T cells recognizing mutated self-antigens (Gros et al., 2016; Kvistborg et al., 2012; McMahan & Slansky, 2007). High affinity T cells display enhanced survival, expansion capacity and tumor control (Martinez-Usatorre et al., 2018; Schmid et al., 2010). In fact, recent clinical trials using neoantigen tumor vaccines showed prolonged progression free survival in melanoma patients (Ott et al., 2017; Sahin et al., 2017), while only modest clinical efficacy was obtained with TAA vaccines (Romero et al., 2016). However, the highly individual nature of neoantigens constitutes a major technical and economical hurdle for routine clinical application. Thus, the characterization of TAA-specific CD8+ T cell responses may reveal new strategies to enhance their anti-tumor properties. In parallel, the identification of high affinity antigens and CD8+ T cells may be essential to design effective tumor vaccines and adoptive cell transfer therapies. Therefore, in this chapter, we describe how to generate tumor cell lines with stable expression of affinity-ranged antigens and methods to assess T-cell affinity.