Applications of high throughput screening platforms for biologics discovery

Abstract

New drug discovery can be a very challenging and complex process due to the length and costs associated with the endeavor. To address this issue, high throughput screening (HTS) platforms have been instrumental in accelerating drug discovery by rapidly allowing us to test a large number of compounds simultaneously. This has been carried out in the past through the evaluation of small molecule drug candidates against relevant cell types in both two-dimensional (2D) and three-dimensional (3D) formats. More recently, novel biological therapeutics are increasingly being explored as treatments for several genetic diseases and cancer. Hence, it is important to develop similar HTS tools to study the production and evaluation of these biological products in the necessary context. In this thesis, the development of new HTS tools for studying such biological products are further explored. Multiple platforms are discussed, with each focused on different applications in viral vector process development, cancer immunotherapy, infectious disease research and stem cell differentiation. First, for viral vector process development, a high throughput 96-deep well plate platform was developed that enabled high density culture of HEK293 suspension cells for production of lentiviral (LVV) vectors. Using this platform, we were able to show that LVV production can be optimized in microscale cultures and that the results obtained were scalable to larger shake flask and bioreactor cultures. This system can serve as a valuable tool in early-stage bioprocess development. Second, for cancer immunotherapy discovery, a high throughput 330-micropillar microwell sandwich system was utilized to co-culture cancer spheroids with natural killer cells. Using this tool, we were able identify several natural killer cell-antibody-drug combinations that were most effective in causing cytotoxicity in different cancer cell lines. This information can help advance more personalized therapies for patient specific cancer. Third, for infectious disease research, we were able to develop a similar 532-micropillar microwell sandwich platform for screening new antivirals against SARS-CoV-2. We were able to show that a pseudoviral SARS-CoV-2 system can be used to successfully infect target cells on the platform. In the future, this system will be used to study different fucoidan compounds isolated from algae for their antiviral activity using the pseudoviral SARS-CoV-2 system. Finally, to study stem cell differentiation, we were able to establish a 384-pillar well sandwich platform to carry out CRISPR/Cas9 mediated editing in high throughput using an inverted GFP system on HEK293T cells. Moving forward, the roles of different genes in the differentiation process will be investigated in a rapid fashion by genetically modifying pluripotent stem cells with CRISPR/Cas9 and tracking that effect on the differentiation outcome.