DFF45/ICAD restores cisplatin-induced nuclear fragmentation but not DNA cleavage in DFF45-deficient neuroblastoma cells

Abstract

We have previously defined a homozygously deleted region at chromosome 1p36.2-p36.3 in human neuroblastoma cell lines, NB-1 and NB-C201, and identified six genes including DFF45/ICAD within this region. In this study, we found that NB-C201 cells are much more resistant to various genotoxic stresses such as cisplatin (CDDP) than CHP134 and SH-SY5Y cells that do not have the homozygous deletion. To examine a role(s) of DFF45 in the regulation of apoptosis in response to CDDP, we have established stably DFF45-expressing NB-C201 cell clones (DFF45-1 and DFF45-3) and a control cell clone (NB-C201-C) using a retrovirus-mediated gene transfer. In contrast to NB-C201-C cells, DFF45-3 cells displayed apoptotic nuclear fragmentation in response to CDDP. Although CDDP-induced proteolytic cleavage of procaspase-3 and DFF45 in DFF45-3 cells, we could not detect a typical apoptotic DNA fragmentation. Additionally, deletion analysis revealed that C-terminal region of DFF45 is required for inducing nuclear fragmentation. Unexpectedly, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays demonstrated that DFF45 has undetectable effect on CDDP sensitivity of NB-C201 cells. Taken together, our present results suggest that DFF45/DFF40 system may be sufficient for CDDP-induced nuclear fragmentation but not DNA cleavage.

Clinicopathological significance of DNA fragmentation factor 45 and thyroid transcription factor 1 expression in benign and malignant lesions of the gallbladder

“…In addition, in some tumor types, DFF45 expression correlated with tumor progression, differentiation, metastasis and prognosis. Taken together, these findings support a tumor suppressor role of DFF45 [8,10,12,13,15,24].…”

“…Recent clinical studies have convincingly linked DFF45 with tumor progression and poor clinical outcomes in many cancer types, including neuroblastoma, esophageal carcinoma, ovarian endometriomas [9][10][11], and endometrial and ovarian carcinoma [10,[12][13][14][15]. However, the involvement of DFF45 in human GBC has not been reported.…”

Physiological and Pathological Remodeling of Cerebral Microvessels

“…After induction of apoptosis, caspase-3 cleaves the DFF45/ICAD complex and releases DFF40/CAD. It leads to DNA fragmentation and nuclear condensation [ 103 ]. An elevated ratio of the proapoptotic protein BAX and antiapoptotic protein BCL-2 levels [ 104 ], nuclear translocation of apoptosis-inducing factor (AIF), overactivation of poly(ADP-ribose) polymerase-1 (PARP-1) leading to NAD+ depletion and metabolic stress also contribute to BMEC apoptosis [ 105 ].…”

Review of cancer cell resistance mechanisms to apoptosis and actual targeted therapies

“…Deletion of the 1p36.2‐p36.3 locus in neuroblastoma causes a DFF45 mutation and correlates with unfavorable outcome 214,215 . NB‐C201 cells bearing the 1p36.2 mutation are more resistant to cisplatin and DFF45 re‐expression confers sensitivity to drug 216 . In melanoma cells resistant to etoposide and cisplatin, an absence of DNA fragmentation and PARP cleavage were associated with apoptosis deficiency 217 .…”