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Abstract 187: High-throughput screening of cancer spheroids demonstrates sensitivity to combination chemotherapy

Abstract We have designed and manufactured a miniaturized 3D cell culture format called NaviPlate. The NaviPlate contains a novel geometry to support the generation of cancer spheroids for robust and sensitive complex biological assays. Cells added to the NaviPlate spontaneously form spheroids, consistent with the cell line phenotype reported in the literature when using U-bottom multi-well formats. In addition, we have been able to perform assays such as cytotoxicity with a minimum number of 200 cells/well, representing a 5-50-fold improvement on existing 3D cell culture assays.Using the NaviPlate, we examined the response to chemotherapy of four commonly used cancer cell lines: LNCaP, AR mutant lymph-node derived prostate cancer; A549, KRAS mutant/EGFR wt NSCLC; HCT116, KRAS mutant/p53 wt colon cancer; and MDA-MB-231 triple negative breast cancer. First, the lines were exposed to three types of chemotherapy with distinct modes of action: 5-FU (DNA damage), Docetaxel (inhibition of microtubular polymerization) and Flavopiridiol (pan-CDK inhibition). Except for Flavopiridiol in A549 cells, all cell lines were resistant to chemotherapy, when grown in 3D, inside the NaviPlate. Furthermore, we were able to show that this resistance was dependent on the 3D formation of spheroids, as HCT116 cells exposed to chemotherapy before forming spheroids were still sensitive to treatment. Interestingly, in A549 cells, which form less tight spheroids, the effect of 3D clustering was less profound on the response to monotherapy. Lastly, we explored NaviPlate as a platform to identify best chemotherapy combination partners. We combined the three chemotherapies in all cell lines, with most combinations efficiently killing the spheroids. On note, the commonly used combination of 5-FU and Docetaxel had no statistically significant effect on the viability of either A549 or MDA-MB-231 cells.In conclusion, NaviPlate is an easy to use, cancer spheroid platform for the identification of chemotherapy combination partners and thus a useful tool for exploring personalized oncology approaches in the clinic. Citation Format: Elad Katz, Maureen R. Deehan, Russell D. Petty, Paul Davies. High-throughput screening of cancer spheroids demonstrates sensitivity to combination chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 187.

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The Bio-Tribological Characteristics of Synthetic Tissue Grafts

The use of synthetic connective tissue grafts became popular in the mid-1980s, particularly for anterior cruciate ligament reconstruction; however, this trend was soon changed given the high failure rate due to abrasive wear. More than 20 years later, a vast range of grafts are available to the orthopaedic surgeon for augmenting connective tissue following rupture or tissue loss. While the biomechanical properties of these synthetic grafts become ever closer to the natural tissue, there have been no reports of their bio-tribological (i.e. bio-friction) characteristics. In this study, the bio-tribological performance of three clinically available synthetic tissue grafts, and natural tendon, was investigated. It was established that the natural tissue exhibits fluid-film lubrication characteristics and hence is highly efficient when sliding against opposing tissues. Conversely, all the synthetic tissues demonstrated boundary or mixed lubrication regimes, resulting in surface-surface contact, which will subsequently cause third body wear. The tribological performance of the synthetic tissue, however, appeared to be dependent on the macroscopic structure. This study indicates that there is a need for synthetic tissue designs to have improved frictional characteristics or to use a scaffold structure that encourages tissue in-growth. Such a development would optimize the bio-tribological properties of the synthetic tissue and thereby maximize longevity.

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Open Access
Radiofrequency-generated glow discharge treatment: potential benefits for polyester ligaments

AbstractThis multicenter study has revealed that treating a woven polyethylene terephthalate (polyester) ligament with a radiofrequency (RF)-generated glow discharge (RFGD) produces marked benefits in terms of increased cell attachment and proliferation on the implant surface. In vitro tests of the same material revealed that the number of synovial fibroblasts attached to the treated samples after 14 days was four times that of the untreated material. Many of the cells were spread over the surface of a single filament, and some formed bridges between one filament and the next. The incorporation of [3H]-thymidine by synovial stromal cells (a measure of the amount of cell division) growing on the treated material was five times that on the untreated samples. The amount of DNA present on the treated material was also found to be almost an order of magnitude greater than that on untreated samples. This increase in cell attachment and proliferation is almost certainly related to a notable increase in wettability of the polyester surface induced by treatment. Mechanical tests revealed that, for ligaments with a nomi¬nal ultimate tensile strength of 2100 N, RF-generated glow treatment reduced the ligament’s strength by 12% but increased its stiffness by 15%. After a medium-term fati¬gue test (10.8 million cycles), however, there appeared to be recovery of the mechanical properties, with the strength and stiffness of untreated and treated samples being essentially the same. After exhaustive fatigue tests (more than 62 million cycles) the residual strength of the treated ligaments was only 9% lower than that of the unfatigued and untreated ligaments.

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