Investigation of mTOR, JAK/STAT, and Hedgehog pathways inhibitor effect on the proliferation of haematological cancer cell lines

Constitutively activated JAK/STAT signaling pathway is a common feature of the BCR/ABL-negative classic myeloproliferative neoplasms (MPN). JAK2 small-molecule inhibitors have been proven to be clinically efficacious; however, they are not mutation-specific and competent enough to suppress neoplastic clonal haematopoiesis. There is a need for exploring new therapeutic strategies for MPN. Additional signaling systems, such as PI3K/Akt/mTOR and Hedgehog, are a potential treatment target. The aim of this study was to characterise and compare the effects of specific JAK/STAT, PI3K/Akt/mTOR, and Hedgehog signaling inhibitors in haematological cell cultures. JAK2 p.V617F mutated SET-2 and JAK2 wild-type UT-7 human cell lines were employed in our study. The effect of specific signaling pathway inhibitors was studied as time- and dose-response experiments. Viability was measured by trypan blue exclusion and alamarBlue assays. IC50 values were used to compare the effectiveness of inhibitors in decreasing cell viability. Independent sample t-test was used for statistical comparisons between experimental groups. p < 0.05 was considered significant. Our results indicate that all specific inhibitors progressively reduced the number of viable cells as the concentration and exposure duration increased. Inhibitors impaired the proliferation of JAK2 mutated cells at significantly lower doses compared to wild-type JAK2 cell line. These in vitro data indicate that JAK/STAT and alternative PI3K/Akt/mTOR and Hedgehog inhibitors have a potential anti-proliferative efficacy. Future studies, involving direct screening of PI3K/Akt/ mTOR, JAK/STAT, and Hedgehog signaling molecules activity, at gene and protein level in cell-based MPN model, are required.