An Automated High-Throughput Screening (HTS) Spotter for 3D Tumor Spheroid Formation.

Three-dimensional (3D) culture platforms have been adopted in a high-throughput screening (HTS) system to mimic in vivo physiological microenvironments. The automated dispenser has been established commercially to enable spotting or distributing non-viscous or viscous biomaterials onto microplates. However, there are still challenges to the precise and accurate dispensation of cells embedded in hydrogels such as Alginate- and Matrigel-extracellular matrices. We developed and improved an automated contact-free dispensing machine, the ASFA SPOTTER (V5 and V6), which is compatible with 96- and 384-pillar/well plates and 330- and 532-micropillar/well chips for the support of 3D spheroid/organoid models using bioprinting techniques. This enables the distribution of non-viscous and viscous biosamples, including chemical drugs and cancer cells, for large-scale drug screening at high speed and small volumes (20 to 4000 nanoliters) with no damage to cells. The ASFA SPOTTER (V5 and V6) utilizes a contact-free method that minimizes cross-contamination for the dispensation of encapsulated tissue cells with highly viscous scaffolds (over 70%). In particular, the SPOTTER V6 does not require a washing process and offers the advantage of almost no dead volume (defined as additional required sample volume, including a pre-shot and flushing shot for dispensing). It can be successfully applied for the achievement of an organoid culture in automation, with rapid and easy operation, as well as miniaturization for high-throughput screening. In this study, we report the advantages of the ASFA SPOTTER, which distributes standard-sized cell spots with hydrogels onto a 384-pillar/well plate with a fast dispensing speed, small-scale volume, accuracy, and precision.

Delphinidin induces apoptosis via cleaved HDAC3-mediated p53 acetylation and oligomerization in prostate cancer cells.

Delphinidin is a major anthocyanidin compound found in various fruits. It has anti-inflammatory, anti-oxidant, and various other biological activities. In this study, we identified the epigenetic modulators that mediate the apoptotic effect of delphinidin in human prostate cancer cells. We found that treatment of LNCaP cells (a p53 wild-type, human prostate cancer cell line) with delphinidin increased caspase-3, -7, and -8 activity, whereas it decreased histone deacetylase activity. Among class I HDACs, the activity of HDAC3 was specifically inhibited by delphinidin. Moreover, the induction of apoptosis by delphinidin was dependent on caspase-mediated cleavage of HDAC3, which results in the acetylation and stabilization of p53. We also observed that delphinidin potently upregulated pro-apoptotic genes that are positively regulated by p53, and downregulated various anti-apoptotic genes. Taken together, these results show that delphinidin induces p53-mediated apoptosis by suppressing HDAC activity and activating p53 acetylation in human prostate cancer LNCaP cells. Therefore, delphinidin may be useful in the prevention of prostate cancer.