Selected nitrostyrene compounds demonstrate potent activity in chronic lymphocytic leukaemia cells, including those with poor prognostic markers

The nitrostyrene scaffold was previously identified as a lead target structure for the development of effective compounds targeting Burkitt's lymphoma. The present study aimed to develop these compounds further in haematological malignancies, including chronic lymphocytic leukaemia (CLL). Cellular viability, flow cytometry and lactate dehydrogenase assays, amongst others, were used to examine the effects of nitrostyrene compounds on CLL cells, including a cell line representing disease with poor prognosis (HG-3) and in ex vivo CLL patient samples (n=14). The results demonstrated that two representative nitrostyrene compounds potently induced apoptosis in CLL cells. The pro-apoptotic effects of the compounds were found to be reactive oxygen species and caspase-dependent, and had minimal effects on the viability of normal donor peripheral blood mononuclear cells. Nitrostyrene compounds exhibited synergistic augmentation of apoptosis when combined with the phosphatidylinositol 3-kinase inhibitor idelalisib and demonstrated potent toxicity in ex vivo CLL cells, including those co-cultured with bone marrow stromal cells, making them more resistant to apoptosis (n=8). These compounds also demonstrated activity in samples from patients with poor prognostic indicators; unmutated immunoglobulin heavy chain genes, expression of CD38 and deletions in chromosomes 17p and 11q. These results suggest that this class of pharmaceutically active compounds offer potential in the treatment of CLL.