Effects of extracts from regenerating organisms on differentiation of the human myeloid leukaemia HL-60 cell line

Abstract

Acute myeloid leukaemia (AML) is the most common form of acute leukaemia in adults, constituting about 80% of cases. Although remarkable progress has been made in the therapeutic scenario for patients with AML, research and development of new and effective anticancer agents to improve patient outcome and minimize toxicity are needed. In this study, the antitumour activity of crude extracts from two regenerative organisms, a fresh water planarian species-Malta (PSM) and the axolotl Ambystoma mexicanum (AXO) were assessed in vitro on the human AML HL-60 cell line. The anticancer activity was evaluated in terms of ability to influence proliferative activity, cell viability, cell cycle arrest, and differentiation. Moreover, gene expression analysis was performed to evaluate the genes involved in the regulation of these processes. The PSM extract exhibited a selective cytotoxic effect on HL-60 cells when compared to normal lymphocytes. Furthermore, cell cycle analysis and Annexin V/PI assay showed that the PSM extract induced apoptosis in HL-60 cells. AXO crude extract exhibited antiproliferative but not cytotoxic activities on HL-60 cells, with cell cycle arrest in the G0/G1 phase. Both PSM and AXO extract clearly decreased the nucleo/cytoplasmic ratio of the HL-60 cells, with an increase in nitroblue tetrazolium-positive cells. Furthermore, PSM treated cells showed an increase in CD11b- and CD14-positive cells, whilst AXO-treated HL-60 cells showed an increase in the expression of CD11b, suggesting that the extracts were able to stimulate myeloid differentiation. Finally, PSM and AXO extracts caused upregulation of CEBPA, CEBPB, CEBPE, SPI1, and downregulation of c-MYC, with PSM extract showing an increased expression of CDKN2C and reduction of CDKN1A. The data clearly show the potential anticancer activity of PSM and AXO on HL-60 cells and sug