Antitumor effects with apoptotic death in human promyelocytic leukemia HL‐60 cells and suppression of leukemia xenograft tumor growth by irinotecan HCl

• Published in: Environmental toxicology 2015-07, Vol.30 (7), p.803-815
• Main Authors: Chen, Yung‐Liang, Chueh, Fu‐Shin, Yang, Jai‐Sing, Hsueh, Shu‐Ching, Lu, Chi‐Cheng, Chiang, Jo‐Hua, Lee, Ching‐Sung, Lu, Hsu‐Feng, Chung, Jing‐Gung
• Format: Article
• Language: English
• Subjects: Animals; antileukemia; antineoplastic agents; Antineoplastic Agents, Phytogenic - therapeutic use; Antineoplastic Agents, Phytogenic - toxicity; apoptosis; Apoptosis - drug effects; Apoptosis Regulatory Proteins - metabolism; Camptothecin - analogs & derivatives; Camptothecin - therapeutic use; Camptothecin - toxicity; Caspase 3 - metabolism; caspase-12; caspase-9; Cell Cycle Proteins - metabolism; cell growth; cyclin-dependent kinase; cyclins; cytotoxicity; Disease Models, Animal; DNA Damage - drug effects; flow cytometry; fluorescent antibody technique; G1 Phase Cell Cycle Checkpoints - drug effects; HL-60 Cells; Humans; in vitro; in vivo studies; interphase; Irinotecan; irinotecan HCl; leukemia; Leukemia, Promyelocytic, Acute - drug therapy; Leukemia, Promyelocytic, Acute - metabolism; Leukemia, Promyelocytic, Acute - pathology; Male; Membrane Potential, Mitochondrial - drug effects; Mice; Mice, Inbred BALB C; Mice, Nude; Microscopy, Confocal; mitochondria; neoplasm cells; quantitative polymerase chain reaction; Transplantation, Heterologous; tumor xenograft model; Western blotting
• ISSN: 1520-4081; 1522-7278
• DOI: 10.1002/tox.21959

Irinotecan HCl (CPT‐11) is an anticancer prodrug, but there is no available information addressing CPT‐11‐inhibited leukemia cells in in vitro and in vivo studies. Therefore, we investigated the cytotoxic effects of CPT‐11 in promyelocytic leukemia HL‐60 cells and in vivo and tumor growth in a leukemia xenograft model. Effects of CPT‐11 on HL‐60 cells were determined using flow cytometry, immunofluorescence staining, comet assay, real‐time PCR, and Western blotting. CPT‐11 demonstrated a dose‐ and time‐dependent inhibition of cell growth, induction of apoptosis, and cell‐cycle arrest at G0/G1 phase in HL‐60 cells. CPT‐11 promoted the release of AIF from mitochondria and its translocation to the nucleus. Bid, Bax, Apaf‐1, caspase‐9, AIF, Endo G, caspase‐12, ATF‐6b, Grp78, CDK2, Chk2, and cyclin D were all significantly upregulated and Bcl‐2 was down‐regulated by CPT‐11 in HL‐60 cells. Induction of cell‐cycle arrest by CPT‐11 was associated with changes in expression of key cell‐cycle regulators such as CDK2, Chk2, and cyclin D in HL‐60 cells. To test whether CPT‐11 could augment antitumor activity in vivo, athymic BALB/cⁿᵘ/ⁿᵘ nude mice were inoculated with HL‐60 cells, followed by treatment with either CPT‐11. The treatments significantly inhibited tumor growth and reduced tumor weight and volume in the HL‐60 xenograft mice. The present study demonstrates the schedule‐dependent antileukemia effect of CPT‐11 using both in vitro and in vivo models. CPT‐11 could potentially be a promising agent for the treatment of promyelocytic leukemia and requires further investigation. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 803–815, 2015.