Tumour-on-chip microfluidic platform for assessment of drug pharmacokinetics and treatment response.

Microphysiological in vitro systems are platforms for preclinical evaluation of drug effects and significant advances have been made in recent years. However, existing microfluidic devices are not yet able to deliver compounds to cell models in a way that reproduces the real physiological drug exposure. Here, we introduce a novel tumour-on-chip microfluidic system that mimics the pharmacokinetic profile of compounds on 3D tumour spheroids to evaluate their response to the treatments. We used this platform to test the response of SW620 colorectal cancer spheroids to irinotecan (SN38) alone and in combination with the ATM inhibitor AZD0156, using concentrations mimicking mouse plasma exposure profiles of both agents. We explored spheroid volume and viability as a measure of cancer cells response and changes in mechanistically relevant pharmacodynamic biomarkers (γH2AX, cleaved-caspase 3 and Ki67). We demonstrate here that our microfluidic tumour-on-chip platform can successfully predict the efficacy from in vivo studies and therefore represents an innovative tool to guide drug dose and schedules for optimal efficacy and pharmacodynamic assessment, while reducing the need for animal studies.

SLFN11 informs on standard of care and novel treatments in a wide range of cancer models.

BACKGROUND: Schlafen 11 (SLFN11) has been linked with response to DNA-damaging agents (DDA) and PARP inhibitors. An in-depth understanding of several aspects of its role as a biomarker in cancer is missing, as is a comprehensive analysis of the clinical significance of SLFN11 as a predictive biomarker to DDA and/or DNA damage-response inhibitor (DDRi) therapies. METHODS: We used a multidisciplinary effort combining specific immunohistochemistry, pharmacology tests, anticancer combination therapies and mechanistic studies to assess SLFN11 as a potential biomarker for stratification of patients treated with several DDA and/or DDRi in the preclinical and clinical setting. RESULTS: SLFN11 protein associated with both preclinical and patient treatment response to DDA, but not to non-DDA or DDRi therapies, such as WEE1 inhibitor or olaparib in breast cancer. SLFN11-low/absent cancers were identified across different tumour types tested. Combinations of DDA with DDRi targeting the replication-stress response (ATR, CHK1 and WEE1) could re-sensitise SLFN11-absent/low cancer models to the DDA treatment and were effective in upper gastrointestinal and genitourinary malignancies. CONCLUSION: SLFN11 informs on the standard of care chemotherapy based on DDA and the effect of selected combinations with ATR, WEE1 or CHK1 inhibitor in a wide range of cancer types and models.

Assessment of orthodontic biomaterials' cytotoxicity: an in vitro study on cell culture.

OBJECTIVE: Orthodontists use various biomaterials such as molar bands, brackets, archwires, transpalatal archwires, facial masks and other auxiliary devices. One of the essential properties of these materials should be the biocompatibility. The aim of this study was to evaluate the biocompatibility of some orthodontic biomaterials like stainless steel archwires, brackets and NiTi (nickel-titanium alloy) coil springs. MATERIALS AND METHODS: The studies were performed in vitro using human fibroblasts cultures on which the orthodontic materials were applied. The positive control was the copper amalgam. Readings of the cell reactions were performed at three and six days. RESULTS: It was observed that the materials used in the study cause cell alterations of variable intensity. The metallic brackets represent an important cell stress factor causing shape changes. For the metallic brackets, a preferential tropism for different areas of the bracket was also obvious. We observed a preferential tropism for the areas between the NiTi coil spring spirals. For the stainless steel archwires, we observed at six days a decay of cell density and also a higher amount of cells near the archwire areas on which bends were performed. CONCLUSIONS: All biomaterials analyzed in our study cause cellular changes of varying intensity without necessarily showing a cytotoxic character.

In vitro evaluation of curcumin effects on breast adenocarcinoma 2D and 3D cell cultures.

UNLABELLED: Breast adenocarcinoma cell line MDA-MB-231, even if it expresses low levels of E-cadherin, still readily form multicellular aggregates of cells, namely spheroids. Curcumin is a diarylheptanoid antitumoral drug while it significantly inhibits cell migration, invasion, and colony formation in vitro and reduces tumor growth and liver metastasis in vivo. Curcumin photoactivation may enhance antiapoptotic role against cancer cells. AIM: To evaluate the effect of low curcumin concentrations, ranged from 1.9 to 15 µM, with and without photoactivation, using a manufactured 670 nm LED-matrix. A secondary aim was to evaluate the ideal method to produce easy-to-use tumor cell spheroids, comparing two low adherence plate supports. MATERIALS AND METHODS: Breast adenocarcinoma cell line MDA-MB-231 were cultured according to 2D monolayer and 3D spheroid models then submitted to normal and photoactivated curcumin in micromolar concentrations. MTT assay was used to evaluate cell viability following curcumin application on cells. On 2D cell cultures, curcumin inhibits cell tumor development and proliferation at concentrations of 15 µM, with a viability of 65.7% at 48 hours incubation time. A decreased viability up to 25% for a concentration of 15 µM was recorded following photoactivation and cytotoxic action on breast cancer tumor cell line continued at concentrations of 7.5 and 3.75 µM. Curcumin photoactivation increases pro-apoptotic effects in both 2D and 3D tumor cell culture models and also responsiveness to curcumin is slightly reduced in spheroid-like structures. Thus, 3D tumor cell culture systems appear to be the ideal environment for in vitro assays regarding anticancer drug effects on cell viability.

Preparation and cytocompatibility evaluation for hydrosoluble phosphorous acid-derivatized cellulose as tissue engineering scaffold material.

Chemical modification of cellulose by phosphorylation enhances its bioactivity and provides new derivatives and materials with specific end uses. In the present study, cellulose derivatized with phosphorous acid was obtained using the reaction of microcrystalline cellulose with phosphorous acid-urea mixture, in molten state, in comparison with others methods that used different solvents and catalysts. Completely water soluble films with a substitution degree close to one were obtained and characterized by analytical and spectral analysis (FT-IR, (31)P NMR), contact angle, metallographic microscopy and atomic force microscopy (AFM). 31P NMR spectra of derivatized cellulose showed a signal at 2.58 ppm (assigned to P-O-C6) while the doublets at 4.99-5.29 and at 7.38 ppm were assigned to P-O-C2 and P-O-C3, respectively; thus, the formation of monosubstituted phosphorous acid esters of cellulose is advocated. Contact angle measurements showed that the work of adhesion is more important in water than in ethylene glycol, for the phosphorous acid derivatized cellulose. The cytocompatibility of this hydrosoluble derivatized cellulose was tested by direct contact and also by indirect assays on normal human dermal fibroblasts and on osteoblast-like cells (human osteosarcoma). Cell growth on phosphorylated cellulose pellicle and the results from viability assays had shown a good cytocompatibility and lack of toxicity. Phosphorous acid derivatized cellulose would offer a promising biomaterial, useful as scaffolds for new biopolymer composites, and subject for further development as an ionic crosslinker.

Common trace elements alleviate pain in an experimental mouse model.

Trace elements represent a group of essential metals or metaloids necessary for life, present in minute amounts. Analgesic adjuvants can enhance the effect of other pain drugs or be used for pain control themselves. Previous studies on the effects of trace elements on nociception and their potential use as analgesic adjuvants have yielded conflicting results. In this study, we tested the hypothesis that three vital trace elements (Zn²âº, Mg²âº, Cu²âº) have direct antinociceptive effects. Groups of eight Swiss mice were intraperitoneally (i.p) injected with incremental concentrations of Zn²âº sulfate (0.5, 2.0 mg/kg), Zn²âº citrate (0.125, 0.5 mg/kg), Mg²âº chloride (37.5, 75, 150 mg/kg), Cu²âº chloride (0.5, 1.0, 2.0 mg/kg), and Cu²âº sulfate (0.5, 1.0 mg/kg) or saline (control). Evaluations were made by hot plate (HP) and tail flick (TF) tests for central antinociceptive effect, writhing test (WT) for visceral antinociceptive effect, and activity cage (AC) test for spontaneous behavior. Zn²âº induced pain inhibition in HP/TF tests (up to 17%) and WT (up to 25%), with no significant differences among the salts used. Mg²âº salts induced pain inhibition for all performed tests (up to 85% in WT). Cu²âº salts showed antinociceptive effects for HP/TF (up to 28.6%) and WT (57.28%). Only Mg²âº and Cu²âº salts have displayed significant effects in AC (Mg²âº anxiolytic/depressant effect; Cu²âº anxiolytic effect). We interpret these data to mean that all tested trace elements induced antinociceptive effects in central and visceral pain tests. Our data indicate the potential use of these cheap adjuvants in pain therapy.

Manganese SOD mimics are effective against heat stress in a mutant fission yeast deficient in mitochondrial superoxide dismutase.

UNLABELLED: Previous studies revealed a close connection between heat shock and manganese-dependent superoxide dismutase (SOD2) in eukaryotes. This paper shows that SOD mimics based on manganese complexes caused an increase in thermotolerance for a mutant fission yeast deficient in mitochondrial superoxide dismutase. Manganese compounds used for tests are SOD mimics, from two different classes: salen manganese (EUK-8) and Mn porphyrin (Mn(III)TE-2-PyP(5+)). The tests were conducted using a Schizosaccharomyces pombe model, comparing the viability of two strains at chronic heat stress (37°C)--a wild type versus a strain with the mitochondrial superoxide dismutase gene deleted [SOD2(-)]. The presence of massive free radical species in S. pombe SOD2(-) was demonstrated using a luminol-enhanced chemiluminescence test derived from a menadione-mediated survival protocol. CONCLUSIONS: Survival tests revealed that the SOD2-deleted S. pombe is about 100 times more sensitive to heat stress than the wild-type strain. This survival deficit can be corrected by EUK-8 and Mn(III)TE-2-PyP(5+) to almost the same degree but not by manganese chloride II (MnCl(2)). Using a simple spot assay for viability testing, this new model proved to be an easy alternative for the initial estimation of manganese SOD mimics efficiency.