Nuclear Translocation of DNase II and Acid Phosphatase during Radiation-induced Apoptosis in HL60 Cells

Abstract

DNase II is involved in DNA fragmentation induced by a variety of treatments. However, according to past reports DNase II does not directly generate TUNEL (in situ DNA end labeling)-positive cells. The purpose of this study was to investigate the participation of acid phosphatase in the generation of TUNEL-positive cells. DNase II-like proteins, whose molecular weights were 32-kDa, were detected in nuclear extracts of HL60 human myeloid leukemia cells post g-irradiation by SDS-PAGE and immunohistochemistry. Acidic nuclease activity was especially active in 32-kDa bands. TUNEL assay was positive post g-irradiation. From measurements of the activity of acid phosphatase, the activity in nuclear extracts increased remarkably post g-irradiation. g-irradiation can directly or indirectly activate DNase II. Once DNase II and acid phosphatase have been translocated from lysosomes into the nuclei, DNase II generates TUNEL reactive ends in combination with acid phosphatase.

Butyrate-induced proapoptotic and antiangiogenic pathways in EAT cells require activation of CAD and downregulation of VEGF

“…It is evident from our results that BuA can activate CAD, which is associated with its inhibitor ICAD in the cytosol [42]. Several studies have shown that activation of endonuclease II is required for DNA fragmentation and degradation during cell death [35][36][37]43]. Our results clearly demonstrate that activation of endonuclease-II upon BuA-treatment, which supports our view that BuA could activate both CAD and DNase-II for complete DNA degradation in EAT cells, and thus suggest that apoptotic pathway induced by BuA in EAT cells is at least in part mediated by the activation of CAD and DNase-II.…”

“…Several studies have shown that activation of endonuclease II is critical for DNA fragmentation and degradation during cell death [35][36][37]. Hence, an attempt was made to find out whether BuA-induced DNA degradation is associated with activation of endonuclease-II in EAT cells.…”

Deoxyribonuclease I is Essential for DNA Fragmentation Induced by Gamma Radiation in Mice

“…In fact, some other studies suggested the possible involvement of other endonucleases in radiation-induced lymphoid and hematopoietic cell injury. For example, Nakagami et al showed that DNase II and acid phosphatase translocated to the nuclei after irradiation of HL60 human myeloid leukemia cells and generated TUNEL-positive DNA breaks by the combined action of the enzymes (5). McIlroy et al reported that exposing Jurkat cells to γ radiation induced caspase-activated DNase (7).…”

“…The exact endonuclease that mediates radiation-induced DNA fragmentation is unknown. Several cytotoxic (apoptotic) endonucleases have been shown to be induced in response to γ or β-particle irradiation, including deoxyribonuclease (DNase) I (3, 4), DNase II (5), DNase γ (6) and caspase-activated DNase (CAD) (7). Recent study showed that inhibition of DNase γ in rat splenocytes protected them from γ-radiation injury (8).…”

Autophagy plays a potential role in the process of sea cucumber body wall “melting” induced by UV irradiation

“…Huo et al [19] found that ACP activity of chick embryo macrophages increased with the occurrence of apoptotic cells, and by which macrophages could engulf and eliminate apoptotic cells or bodies. Nakagami et al [20] observed that the activity of ACP in nuclear extracts of HL60 human myeloid leukemia cells post -irradiation increased remarkably, and concluded that once DNase and ACP have translocated from lysosomes into the nuclei, and DNase II generates TUNEL reactive ended in combination with ACP. In this study the expression of ACP activity was strongly improved by UV irradiation, together with previous documents, clearly indicating that ACP might play a role in UV-induced "melting", although the detailed mechanism through which ACP functions remains understood.…”