Multiscale optical phase fluctuations link disorder strength and fractal dimension of cell structure.

Optical methods for examining cellular structure based on endogenous contrast rely on analysis of refractive index changes to discriminate cell phenotype. These changes can be visualized using techniques such as phase contrast microscopy, detected by light scattering, or analyzed numerically using quantitative phase imaging. The statistical variations of refractive index at the nanoscale can be quantified using disorder strength, a metric seen to increase with neoplastic change. In contrast, the spatial organization of these variations is typically characterized using a fractal dimension, which is also seen to increase with cancer progression. Here, we seek to link these two measurements using multiscale measurements of optical phase to calculate disorder strength and in turn to determine the fractal dimension of the structures. First, quantitative phase images are analyzed to show that the disorder strength metric changes with resolution. The trend of disorder strength with length scales is analyzed to determine the fractal dimension of the cellular structures. Comparison of these metrics is presented for different cell lines with varying phenotypes including MCF10A, MCF7, BT474, HT-29, A431, and A549 cell lines, in addition to three cell populations with modified phenotypes. Our results show that disorder strength and fractal dimension can both be obtained with quantitative phase imaging and that these metrics can independently distinguish between different cell lines. Furthermore, their combined use presents a new approach for better understanding cellular restructuring during different pathways.

Establishment and characterization of urothelial carcinoma cell lines with and without BRAF mutation (V595E) in dogs.

Each 5 urothelial carcinoma (UC) cell lines with and without the v-Raf murine sarcoma virus oncogene homolog B (BRAF) gene mutation (V595E) were established and examined V595E-related tumorigenic characteristics in dogs. No typical morphological features were observed in cloned cells with and without V595E. The cell proliferation of both cloned cells showed logarithmic growth curve and those doubling time were 24.9 ± 4.1 h in V595E ( +) and 29.3 ± 11.3 h in V595E ( -). On the growth curve of xenotransplanted tumor in severe combined immunodeficiency mice, 3 out of 5 V595E ( +) and 2 out of 5 V595E ( -) cloned cells revealed gradually and remarkably increasing curve, indicating clearly tumorigenicity. The xenotransplanted tumors with V595E ( +) showed typical features of UC, such as solid proliferation of pleomorphic tumor cells, formation of papillary structure, and glandular structure. Additionally, various vascular formation was observed, probably indicating an advanced growth phase of UC. In mitogen-activated protein kinase (MAPK) signaling pathway, cytoplasmic phosphorylated-BRAF (pBRAF) and cytoplasmic and nuclear phosphorylated-ERK1/2 (pERK1/2) were detected in all 4 tumors with V595E ( +), whereas only cytoplasmic and nuclear pERK1/2 was detected in tumors with V595E ( -). Since V595E can directly activate MAPK signaling pathway, coincidence of V595E with pBRAF (phosphor Thr598/Ser601) indicates acquired resistance to BRAF inhibitors. These established UC cell lines, especially V595E ( +) cell lines, are useful tool for understanding pathophysiological states and controlling therapeutic manners of UC in dogs.

High-Resolution Imaging of Mitochondria and Mitochondrial Nucleoids in Differentiated SH-SY5Y Cells.

Mitochondria are highly dynamic organelles which form intricate networks with complex dynamics. Mitochondrial transport and distribution are essential to ensure proper cell function, especially in cells with an extremely polarised morphology such as neurons. A layer of complexity is added when considering mitochondria have their own genome, packaged into nucleoids. Major mitochondrial morphological transitions, for example mitochondrial division, often occur in conjunction with mitochondrial DNA (mtDNA) replication and changes in the dynamic behaviour of the nucleoids. However, the relationship between mtDNA dynamics and mitochondrial motility in the processes of neurons has been largely overlooked. In this chapter, we describe a method for live imaging of mitochondria and nucleoids in differentiated SH-SY5Y cells by instant structured illumination microscopy (iSIM). We also include a detailed protocol for the differentiation of SH-SY5Y cells into cells with a pronounced neuronal-like morphology and show examples of coordinated mitochondrial and nucleoid motility in the long processes of these cells.

Anterior gradient protein 2 is a marker of tumor aggressiveness in breast cancer and favors chemotherapy­induced senescence escape.

Among the different chemotherapies available, genotoxic drugs are widely used. In response to these drugs, particularly doxorubicin, tumor cells can enter into senescence. Chemotherapy­induced senescence (CIS) is a complex response. Long described as a definitive arrest of cell proliferation, the present authors and various groups have shown that this state may not be complete and could allow certain cells to reproliferate. The mechanism could be due to the activation of new signaling pathways. In the laboratory, the proteins involved in these pathways and triggering cell proliferation were studied. The present study determined a new role for anterior gradient protein 2 (AGR2) in vivo in patients and in vitro in a senescence escape model. AGR2's implication in breast cancer patients and proliferation of senescent cells was assessed based on a SWATH­MS proteomic study of patients' samples and RNA interference technology on cell lines. First, AGR2 was identified and it was found that its concentration is higher in the serum of patients with breast cancer and that this high concentration is associated with metastasis occurrence. An inverse correlation between intratumoral AGR2 expression and the senescence marker p16 was also observed. This observation led to the study of the role of AGR2 in the CIS escape model. In this model, it was found that AGR2 is overexpressed in cells during senescence escape and that its loss considerably reduces this phenomenon. Furthermore, it was shown that the extracellular form of AGR2 stimulated the reproliferation of senescent cells. The power of proteomic analysis based on the SWATH­MS approach allowed the present study to highlight the mammalian target of rapamycin (mTOR)/AKT signaling pathway in the senescence escape mechanism mediated by AGR2. Analysis of the two signaling pathways revealed that AGR2 modulated RICTOR and AKT phosphorylation. All these results showed that AGR2 expression in sera and tumors of breast cancer patients is a marker of tumor progression and metastasis occurrence. They also showed that its overexpression regulates CIS escape via activation of the mTOR/AKT signaling pathway.

Development of an in vitro neuroblastoma 3D model and its application for sterigmatocystin-induced cytotoxicity testing.

Given the increasing importance of establishing better risk assessments for mycotoxins, novel in vitro tools for the evaluation of their toxicity are mandatory. In this study, an in vitro 3D spheroid model from SH-SY5Y cells, a human neuroblastoma cell line, was developed, optimized and characterized to test the cytotoxic effects caused by the mycotoxin sterigmatocystin (STE). STE induced a concentration- and time-dependent cell viability decrease in spheroids. Spheroids displayed cell disaggregation after STE exposure, increasing in a dose-dependent manner and over time. STE also induced apoptosis as confirmed by immunofluorescence staining and Western blot. Following the decreased proliferation and increased apoptosis, STE cytostasis effects were observed by migration assays both in 2D and 3D cell culture. Increased ROS generation, as well as DNA damage were also observed. Taken together, these data highlight the cytotoxic properties of STE and suggest that cell culture models play a pivotal role in the toxicological risk assessment of mycotoxins. The evaluation of cytotoxicity in spheroids (3D) rather than monolayer cultures (2D) is expected to more accurately reflect in vivo-like cell behaviour.

Transcriptional CDK Inhibitors CYC065 and THZ1 Induce Apoptosis in Glioma Stem Cells Derived from Recurrent GBM.

Glioma stem cells (GSCs) are tumour initiating cells which contribute to treatment resistance, temozolomide (TMZ) chemotherapy and radiotherapy, in glioblastoma (GBM), the most aggressive adult brain tumour. A major contributor to the uncontrolled tumour cell proliferation in GBM is the hyper activation of cyclin-dependent kinases (CDKs). Due to resistance to standard of care, GBMs relapse in almost all patients. Targeting GSCs using transcriptional CDK inhibitors, CYC065 and THZ1 is a potential novel treatment to prevent relapse of the tumour. TCGA-GBM data analysis has shown that the GSC markers, CD133 and CD44 were significantly upregulated in GBM patient tumours compared to non-tumour tissue. CD133 and CD44 stem cell markers were also expressed in gliomaspheres derived from recurrent GBM tumours. Light Sheet Florescence Microscopy (LSFM) further revealed heterogeneous expression of these GSC markers in gliomaspheres. Gliomaspheres from recurrent tumours were highly sensitive to transcriptional CDK inhibitors, CYC065 and THZ1 and underwent apoptosis while being resistant to TMZ. Apoptotic cell death in GSC subpopulations and non-stem tumour cells resulted in sphere disruption. Collectively, our study highlights the potential of these novel CKIs to induce cell death in GSCs from recurrent tumours, warranting further clinical investigation.

Chemotherapy Induces Senescence-Like Resilient Cells Capable of Initiating AML Recurrence.

Patients with acute myeloid leukemia (AML) frequently relapse after chemotherapy, yet the mechanism by which AML reemerges is not fully understood. Herein, we show that primary AML cells enter a senescence-like phenotype following chemotherapy in vitro and in vivo. This is accompanied by induction of senescence/inflammatory and embryonic diapause transcriptional programs, with downregulation of MYC and leukemia stem cell genes. Single-cell RNA sequencing suggested depletion of leukemia stem cells in vitro and in vivo, and enrichment for subpopulations with distinct senescence-like cells. This senescence effect was transient and conferred superior colony-forming and engraftment potential. Entry into this senescence-like phenotype was dependent on ATR, and persistence of AML cells was severely impaired by ATR inhibitors. Altogether, we propose that AML relapse is facilitated by a senescence-like resilience phenotype that occurs regardless of their stem cell status. Upon recovery, these post-senescence AML cells give rise to relapsed AMLs with increased stem cell potential. SIGNIFICANCE: Despite entering complete remission after chemotherapy, relapse occurs in many patients with AML. Thus, there is an urgent need to understand the relapse mechanism in AML and the development of targeted treatments to improve outcome. Here, we identified a senescence-like resilience phenotype through which AML cells can survive and repopulate leukemia.This article is highlighted in the In This Issue feature, p. 1307.

Cytotoxic activity of the chloroform fraction of Piper aduncum and its effect on the cell cycle in gastric cancer cell lines. / Actividad citotóxica de la fracción clorofórmica de Piper aduncum y su efecto en el ciclo celular en líneas celulares de cáncer gástrico.

OBJECTIVES: To evaluate the cytotoxic activity of the chloroform fraction of the Piper aduncum methanolic extract (PAMoCl) and its effect on the cell cycle in two gastric cancer cell lines: AGS and KATO III. MATERIALS AND METHODS: The cytotoxic effect of PAMoCl was evaluated in cell lines AGS and KATO III. The following PAMoCl concentrations were tested, 1.25, 2.5, 5, 10, 20, 40, 80 and 160 µg/mL. Resazurine was used to evaluate cell viability. In the cell cycle assay, the cells were treated with 19.62 µg/mL and 39.23 µg/mL of PAMoCl for AGS as well as 87.49 µg/mL and 160 µg/mL for KATO III. After 24 hours both cell lines were analyzed by flow cytometry. RESULTS: PAMoCl showed cytotoxic activity, inhibiting cell growth by 50%. It presented a (IC50) of 39.23 µg/mL and 87.49 µg/mL at 24 hours and a (IC50) of 49.47 µg/mL and 64.68 µg/mL at 48 hours against AGS and KATO III cell lines, respectively. In addition, it was observed that PAMoCl has an effect on the cell cycle, it causes an accumulation of cells in the G2/M phase. CONCLUSIONS: PAMoCl contains secondary metabolites with cytotoxic activity that have an effect on the G2/M phase of the cell cycle, in two gastric cancer cell lines, both primary and metastatic. The results of this study will allow us to deepen the search for more effective active ingredients found in PAMoCl for eliminating gastric cancer cells, but with less toxicity for healthy cells.

OBJETIVOS: Evaluar la actividad citotóxica de la fracción clorofórmica del extracto metanólico de Piper aduncum (PAMoCl) y su efecto en el ciclo celular en dos líneas celulares de cáncer gástrico: AGS y KATO III. MATERIALES Y MÉTODOS: El efecto citotóxico de PAMoCl se evaluó en las líneas celulares: AGS y KATO III. Se probaron concentraciones de PAMoCl: 1,25; 2,5; 5; 10; 20; 40; 80 y 160 µg/mL. Para evaluar la viabilidad celular se usó el reactivo resazurina. En el ensayo de ciclo celular las células fueron tratadas con 19,62 µg/mL y 39,23 µg/mL de PAMoCl para AGS, así como 87,49 µg/mL y 160 µg/mL para KATO III. Después de 24 horas ambas líneas celulares fueron analizadas por citometría de flujo. RESULTADOS: PAMoCl mostró actividad citotóxica con una inhibición del crecimiento celular en un 50% (IC50) de 39,23 µg/mL y 87,49 µg/mL a las 24 horas y un IC50 de 49,47 µg/mL y 64,68 µg/mL a las 48 horas frente a las líneas celulares AGS y KATO III, respectivamente. Además, se observó que PAMoCl tiene efecto a nivel del ciclo celular: provoca una acumulación de células en la fase G2/M. CONCLUSIONES: PAMoCl contiene metabolitos secundarios con actividad citotóxica que tienen efecto en la fase G2/M del ciclo celular, en dos líneas celulares de cáncer gástrico tanto primario como metastásico. Los resultados de este estudio permitirán profundizar en la búsqueda de principios activos presentes en PAMoCl que tengan mayor eficacia en la eliminación de células de cáncer gástrico, pero con menor toxicidad en células sanas.

Absence of bovine leukemia virus proviral DNA in Japanese human blood cell lines and human cancer cell lines.

Bovine leukemia virus (BLV) infects cattle worldwide and causes B-cell lymphoma in cattle. BLV has been identified in human breast and lung cancer and in blood, but the association of BLV and human cancer is controversial. In this study, we investigated the existence of BLV in 145 Japanese human blood cell lines and 54 human cancer cell lines, using a new highly sensitive PCR assay that can amplify even one copy of BLV using LTR primers different from those in previous studies on BLV provirus in breast cancer. All samples were found negative for BLV provirus, suggesting that BLV is unlikely to infect humans.

Development of surface functionalized hydroxyapatite nanoparticles for enhanced specificity towards tumor cells.

Nanoparticles coupled with targeting moieties have attracted a great deal of attention for cancer therapy since they can facilitate site-specific delivery of drug and significantly limit the side effects of systemic chemotherapy. In this study, our aim is to develop surface functionalized hydroxyapatite nanoparticles, which could provide binding sites for a cancer cell targeting ligand, folic acid (FA) as well as an anticancer drug, doxorubicin hydrochloride (DOX). In order to attain dual functionalities, hydroxyapatite nanoparticles were functionalized with gelatin molecules. Gelatin, being a protein has both carboxyl and amine moieties, which makes it suitable for binding of DOX and FA. FA was chemically conjugated to the nanoparticles through an EDCNHS coupling reaction. The formation of single-phase hydroxyapatite nanostructure was ascertained by X-ray diffraction studies and the presence of organic moieties on the surface of nanoparticles was evident from Fourier transform infrared spectroscopy, thermogravimetric analysis and U.V.-visible spectroscopy. The FA-conjugated nanoparticles (FA-Gel-HANPs) showed high affinity towards DOX and pH-responsive sustained release of drug with higher release rate under acidic pH conditions, desired for cancer therapy. The FA-Gel-HANPs showed negligible cytotoxicity towards different cell lines (HepG2, WEHI-164, KB, WI-26 VA4 and WRL-68). However, DOX loaded nanoparticles (DOX-FA-Gel-HANPs) exhibited significant toxicity towards these cells, which was however highest in folate receptor (FR)-overexpressing, KB cells. These results were correlated with enhanced cellular uptake of DOX-FA-Gel-HANPs in KB cells in comparison to FR-deficient, WRL-68 cells studied by confocal laser scanning microscopy and flow cytometry. Moreover, cell cycle analysis in KB cells, showed higher sub-G1 population, indicating apoptosis as one of the cell death mechanisms. Overall, this study suggests that DOX-FA-Gel-HANPs could serve as a promising tumor-targeted drug delivery system.

Artificially cloaked viral nanovaccine for cancer immunotherapy.

Virus-based cancer vaccines are nowadays considered an interesting approach in the field of cancer immunotherapy, despite the observation that the majority of the immune responses they elicit are against the virus and not against the tumor. In contrast, targeting tumor associated antigens is effective, however the identification of these antigens remains challenging. Here, we describe ExtraCRAd, a multi-vaccination strategy focused on an oncolytic virus artificially wrapped with tumor cancer membranes carrying tumor antigens. We demonstrate that ExtraCRAd displays increased infectivity and oncolytic effect in vitro and in vivo. We show that this nanoparticle platform controls the growth of aggressive melanoma and lung tumors in vivo both in preventive and therapeutic setting, creating a highly specific anti-cancer immune response. In conclusion, ExtraCRAd might serve as the next generation of personalized cancer vaccines with enhanced features over standard vaccination regimens, representing an alternative way to target cancer.

Characterization of five newly derived canine osteosarcoma cell lines.

BACKGROUND: Canine and human osteosarcomas (OS) are notably similar and have a high rate of metastasis. There is a poor understanding of the tumor development process, predisposing causes, and varying levels of aggression among different cell lines. By characterizing newly developed canine osteosarcoma cell lines, treatments for people and pets can be developed. Of the seven subtypes of OS, three are represented in this group: osteoblastic (the most common), fibroblastic, and giant cell variant. To our knowledge, there are no other giant cell variant canine OS cell lines in the published literature and only one canine fibroblastic osteosarcoma cell line. Understanding the differences between the histologic subtypes in dogs will help to guide comparative research. RESULTS: Alkaline phosphatase expression was ubiquitous in all cell lines tested and invasiveness was variable between the cell lines tested. Invasiveness and oxidative damage were not correlated with in vivo growth rates, where TOT grew the fastest and had the higher percentage of mice with metastatic lesions. TOL was determined to be the most chemo-resistant during cisplatin chemotherapy while TOM was the most chemo-sensitive. CONCLUSIONS: Further comparisons and studies using these cell lines may identify a variety of characteristics valuable for understanding the disease process and developing treatments for osteosarcoma in both species. Some of this data was presented as a poster by KMF at the August 5th, 2017 National Veterinary Scholars Program in Bethesda, MA. Characterization of 5 newly generated canine osteosarcoma cell lines. Kelli Franks, Tasha Miller, Heather Wilson-Robles.

FTIR bio-spectroscopy scattering correction using natural biological characteristics of different cell lines.

Fourier transform infrared (FTIR) spectroscopy is a well-known method of analysis, with various applications, including promising potential for analyzing biological samples. In the bio-spectroscopy of cells, Mie scattering may increase, which then causes spectral distortion, due to the similarity of cell size with the IR medium-wavelength. These changes make the spectrum unreliable. In previous scattering elimination studies, questionable estimations were considered. For instance, all cells were considered as spherical objects or cell size was estimated randomly. In an attempt to provide the best equation based on the natural existence of cells for the FTIR Mie scattering correction, we examined the actual biological data of cells - as opposed to those yielded from mathematical manipulations. So five biological factors: cell size, shape, granularity, circularity, and edge irregularities, for each cell line were considered as factors which cause scattering. For measuring cell size, roundness and edge irregularity, microscopy images were obtained and processed. For evaluating cell line granularity, flow cytometry was used. Finally, by including these factors, an algorithm was designed. To assess the accuracy of the proposed algorithm, the trypsinized cell spectrum was considered as the high scattering spectrum. Cells were also cultured on a MirrIR slide, and their ATR-FTIR spectrum was considered as the minimum scattering spectrum. The algorithm using the abovementioned five characteristics was used for 13 different cell lines, and in some cases the corrected spectrum demonstrated more than 97% resemblance with the ATR spectra of the same cells. A comparison between the results of this algorithm with the Bassan et al. (2017) algorithm for scattering correction that is freely available on the Internet was then conducted on two different cell lines, clearly showing the advantages of our algorithm, in terms of accuracy and precision. Therefore, this method can be viewed as a more suitable solution for scattering correction in cell investigations.

Tumor exosome-based nanoparticles are efficient drug carriers for chemotherapy.

Developing biomimetic nanoparticles without loss of the integrity of proteins remains a major challenge in cancer chemotherapy. Here, we develop a biocompatible tumor-cell-exocytosed exosome-biomimetic porous silicon nanoparticles (PSiNPs) as drug carrier for targeted cancer chemotherapy. Exosome-sheathed doxorubicin-loaded PSiNPs (DOX@E-PSiNPs), generated by exocytosis of the endocytosed DOX-loaded PSiNPs from tumor cells, exhibit enhanced tumor accumulation, extravasation from blood vessels and penetration into deep tumor parenchyma following intravenous administration. In addition, DOX@E-PSiNPs, regardless of their origin, possess significant cellular uptake and cytotoxicity in both bulk cancer cells and cancer stem cells (CSCs). These properties endow DOX@E-PSiNPs with great in vivo enrichment in total tumor cells and side population cells with features of CSCs, resulting in anticancer activity and CSCs reduction in subcutaneous, orthotopic and metastatic tumor models. These results provide a proof-of-concept for the use of exosome-biomimetic nanoparticles exocytosed from tumor cells as a promising drug carrier for efficient cancer chemotherapy.

Correlation of Capacitance and Microscopy Measurements Using Image Processing for a Lab-on-CMOS Microsystem.

We present a capacitance sensor chip developed in a 0.35-µm complementary metal-oxide-semiconductor process for monitoring biological cell viability and proliferation. The chip measures the cell-to-substrate binding through capacitance-to-frequency conversion with a sensitivity of 590 kHz/fF. In vitro experiments with two human ovarian cancer cell lines (CP70 and A2780) were performed and showed the ability to track cell viability in realtime over three days. An imaging platform was developed to provide time-lapse images of the sensor surface, which allowed for concurrent visual and capacitance observation of the cells. The results showed the ability to detect single-cell binding events and changes in cell morphology. Image processing was performed to estimate the cell coverage of sensor electrodes, showing good linear correlation and providing a sensor gain of 1.28 ± 0.29 aF/µm2, which agrees with values reported in the literature. The device is designed for unsupervised operation with minimal packaging requirements. Only a microcontroller is required for readout, making it suitable for applications outside the traditional laboratory setting.

(Cyto)genomic and epigenetic characterization of BICR 10 cell line and three new established primary human head and neck squamous cell carcinoma cultures.

BACKGROUND: Head and neck squamous cell carcinoma cell lines are useful preclinical models to understand the molecular processes underlying the development of such tumors, and to establish targeted therapies. OBJECTIVE: We performed a comprehensive (cyto)genomic and epigenetic characterization of three new established primary human head and neck squamous cell carcinoma cultures and an established, yet undercharacterized cell line: BICR 10. METHODS: Karyotyping, multiplex fluorescence in situ hybridization, array comparative genomic hybridization and methylation-specific multiplex ligation-dependent probe amplification were applied. RESULTS: The three primary cultures turned out to be a near-triploid and BICR 10 near-diploid. Banding and molecular cytogenetic analysis revealed non-random numerical and structural aberrations. The most common rearrangements identified in BICR 10 cell line were non-complex derivatives of reciprocal translocations, in which the breakpoints often appeared in centromeric/near-centromeric regions. In the 3 primary cell cultures the most common rearrangements observed were iso- and derivatives chromosomes derived from translocations. Overall, gains of 7p, 8q and losses at 3p, 8p, 9p, 18q and Xp were present in all four studied samples. Among the analyzed genes, BICR 10 cell line exhibited enhanced methylation of gene promoter; however, in all studied samples PAX5, WT1 and GATA5 were methylated. CONCLUSION: The here reported comprehensive characterization of BICR 10 cell line and the new established cultures enriches the resources available for head and neck cancer research, especially for testing therapeutic agents.

Migration Assay for Leukemic Cells in a 3D Matrix Toward a Chemoattractant.

In leukemia, leukemic cells hijack the hematopoietic stem cell (HSC) microenvironment in the bone marrow-the so-called stem cell niche-by flooding the niche with clonal progeny of leukemic cells. They can exploit signaling pathways which are critical for HSC development to support their own survival, homing, and maintenance. These interactions of leukemic cells with the microenvironment have an impact on therapy progress and patient outcome. Therefore, signals for homing and anchorage of leukemic cells to the bone marrow have to be investigated by using tools that allow the migration of cells toward critical signals. Here, we describe an in vitro migration assay for leukemic cells toward a chemoattractant in a 3D environment exemplified by migration of the cell line OCI-AML3 to a CXC motif chemokine ligand 12 (CXCL12) gradient. For this purpose, a chemotaxis slide is filled with a hydrogel system mimicking the extracellular matrix in vivo. The cells are encapsulated into the hydrogel network during polymerization, and a CXCL12 gradient is introduced in the enclosed chambers to trigger migration. Cell migration in the 3D network of the hydrogel is monitored by time-lapse microscopy. We describe the experimental setup and the tools for cell tracking and data analysis.

Selective redox-responsive theragnosis nanocarrier for breast tumor cells mediated by MnO2/fluorescent carbon nanogel.

A redox-responsive fluorescent carbon nanogel (FCN) was designed as a bioimaging probe for targeted drug delivery to cancer cells. FCN was synthesized by the carbonization of disulfide cross-linked hyaluronic acid in the fluorescence "on" mode, followed by the attachment of manganese oxide (MnO2) nanosheets for fluorescence quenching (fluorescence "off"). We hypothesized that the fluorescence intensity of paclitaxel (PTX)-MnO2/FCN would suddenly increase (fluorescence "on") in the presence of a high level of glutathione (GSH) in cancer cells, owing to the reduction of MnO2 to Mn2+ and cleavage of the disulfide bond. Consequently, PTX would be released from the FCN system. Consistent with this hypothesis, the designed system recovered FCN fluorescence and triggered drug release through the cleavage of the disulfide bond by GSH. Moreover, PTX-MnO2/FCN demonstrated stable fluorescence intensity after GSH treatment, serving as a potential biosensor. PTX-MnO2/FCN exhibited excellent biocompatibility with normal cells and selectively targeted tumor cells, highlighting the therapeutic capabilities of this system. The developed PTX-MnO2/FCN structure may serve as a smart drug delivery system with diagnostic and therapeutic properties, good selectivity, and compatibility, and with excellent potential for biomedical applications.

Tumour-treating fields (TTFields): Investigations on the mechanism of action by electromagnetic exposure of cells in telophase/cytokinesis.

Tumour-treating fields (TTFields) use alternating electric fields which interfere with dividing cells, thereby reducing tumour growth. Previous reports suggest that electrical forces on cell structure proteins interfered with the chromosome separation during mitosis and induced apoptosis. In the present report we evaluate electromagnetic exposure of cells in telophase/cytokinesis in order to further analyse the mechanism of action on cells. We performed numerical electromagnetic simulations to analyse the field distribution in a cell during different mitotic phases. Based thereon, we developed an electric lumped element model of the mitotic cell. Both the electromagnetic simulation and the lumped element model predict a local increase of the specific absorption rate (SAR) as a measure of the electromagnetically induced power absorption density at the mitotic furrow which may help to explain the anti-proliferative effect. In accordance with other reports, cell culture experiments confirmed that TTFields reduce the proliferation of different glioma cell lines in a field strength- and frequency-dependent manner. Furthermore, we found an additional dependence on the commutation time of the electrical fields. The report gives new insights into TTFields' anti-proliferative effect on tumours, which could help to improve future TTFields application systems.