The effects of Abemaciclib on cell cycle and apoptosis regulation in anaplastic thyroid cancer cells.

BACKGROUND: Anaplastic thyroid cancer (ATC) is an aggressive subtype of thyroid cancer, accounting for 1 to 2% of all cases. Deregulations of cell cycle regulatory genes including cyclins, cyclin-dependent kinases (CDKs), and endogenous inhibitors of CDKs (CKIs) are hallmarks of cancer cells and hence, studies indicate the inhibition of CDK4/6 kinases and cell cycle progression as potent therapeutic strategies. In this study, we investigated the anti-tumor activity of Abemaciclib, a CDK4 and CDK6 inhibitor, in ATC cell lines. METHODS AND RESULTS: The ATC cell lines C643 and SW1736 were selected to study the antiproliferative effects of Abemaciclib using a cell proliferation assay and crystal violet staining assay. Annexin V/PI staining and cell cycle analysis by flow cytometry were also performed to examine the effects on apoptosis induction and cell cycle arrest. Wound healing assay and zymography analysis examined the effects of the drug on invasive abilities of ATC cells and Western blot analyses were applied to further study the anti-tumor mechanism of Abemaciclib, in addition to combination treatment with alpelisib. Our data demonstrated that Abemaciclib significantly inhibited cell proliferation and increased cellular apoptosis and cell cycle arrest in ATC cell lines, while considerably reducing cell migration and colony formation. The mechanism seemed to involve the PI3K pathway. CONCLUSION: Our preclinical data highlight CDK4/6 as interesting therapeutic targets in ATC and suggest CDK4/6-blockade therapies as promising strategies in this malignancy.

A Comparative Study of the Bone Marrow- and Umbilical Cord-Derived Mesenchymal Stem Cells (MSCs) Efficiency on Generating MSC-Educated Macrophages (MEMs).

BACKGROUND: Mesenchymal stem cells (MSCs) have gained much more attention in cell therapy and regenerative medicine due to their immunosuppressive effects. MSCs have interaction with other immune cells, such as macrophages (MQs). Bone marrow (BM)-derived MSCs can educate MQs toward MSC-educated MQs (MEMs) which possess an anti-inflammatory immunophenotype. Given this and based on the important limitations of BM collection, we hypothesized whether co-culture of MQs with umbilical cord (UC)-derived MSCs can result in the MEM phenotype. METHODS: First, isolated monocytes cultured for five days to obtain M0 MQs. Then, they were co-cultured with either BM- or UC-MSCs under direct and indirect conditions. After three days of co-culture, MEM-specific surface markers, as well as the gene expression of inflammatory and anti-inflammatory cytokines, were evaluated. RESULTS: Surface expression of CD163/CD206, as specific markers for M2 MQs, increased in MEMs after co-culture with BM- and UC-derived MSCs, while CD80/CD86 expression (specific markers for M1 MQs) didn't change significantly. The mRNA expressions of PDL-1 as well as anti-inflammatory cytokines, including IL-6, IL-10, and TGFß also increased in MEMs after co-culture of UC-MSCs compared to control MQs (p <.05), while the expression of IL-12 was significantly decreased (p<.001). CONCLUSIONS: To the best of our knowledge, this study shows for the first time that the co-culture of MQs with UC-derived MSCs efficiently contributes to the generation of MEMs even greater than BM-MSCs; shedding light on the promising potential of UC as an alternative source to educate MQs in vitro.