Exploring Applications of Human Primary Cells for Drug Screening in Various Cell Culture Systems

Human primary cells are useful pre-clinical models as they more closely mimic the physiology of cells in vivo than continuous cell lines. Here, we explored some of the applications of human primary cells for cytotoxicity assays and drug screening. Cancer is a leading cause of female mortality worldwide and gynecologic cancers have a low survival rate. Further, cytotoxicity is a common side effect of all anti-cancer drugs. We investigated the cytotoxic effects of three anti-cancer drugs (alone or in combination) on three types of normal reproductive cells in vitro. Primary human uterine fibroblasts, cervical epithelial cells, and vaginal epithelial cells along with cervical (SiHa) and vaginal (VK2/E6E7) epithelial cancer cell lines were treated for two days with topotecan, paclitaxel, cisplatin, or a combination of topotecan and cisplatin at concentrations of 0 µM, 0.1 µM, 1 µM, 10 µM, or 100 µM. Cytotoxicity of these chemotherapeutic drugs was assessed by using Reliablue™ Cell Viability Reagent. Both topotecan and paclitaxel significantly induced cytotoxicity in three types of reproductive primary cells at 0.1 µM, while cisplatin significantly decreased the viability of all cells at 1 µM or 10 µM. Topotecan, when used in combination with cisplatin, resulted to a significant increase in cytotoxicity at 0.1 µM, 1 µM, 10 µM, or 100 µM. Furthermore, SiHa and VK2/E6E7 cancer cell lines were less sensitive to the aforementioned chemotherapeutic drugs compared to primary cells. Three-dimensional (3-D) cell culture systems utilizing primary cells may provide more physiologically relevant information and more predictive data in in vitro assays. Primary human skeletal muscle cells can contract under physiological conditions and their contractility may change during tissue injury and repair. To validate a 3-D muscle contraction assay for drug screening applications, we embedded primary human skeletal muscle cells with a collagen matrix and treated them for 10 days with 10 mM 2,3-butanedione 2-monoxime (BDM), a known inhibitor of skeletal muscle contraction. The spontaneous contraction of untreated human skeletal muscle cells was observed in a time-dependent manner during the BDM treatment. The results from these assay systems demonstrate that various types of human primary cells can be used for pre-clinical applications including drug screening, toxicology, and modeling physiological responses.