Defective caspase-3 relocalization in non-small cell lung carcinoma

Abstract

Many anticancer drugs exert their cytotoxicity through DNA damage and induction of apoptosis. Small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC) have di erent sensitivity to treatment with radiation and chemotherapeutic agents with SCLC being more sensitive than NSCLC both in vitro and in vivo. This di erence might be related to the di erent susceptibility of small and non-small cell lung carcinoma to undergo apoptosis. The aim of this study was to investigate if de®ciencies in the apoptotic pathways can explain the intrinsic resistance of NSCLC to anti-cancer treatment. Three di erent triggers were used to induce apoptosis. Etoposide and g-radiation, which are important parts of clinical lung cancer treatment, induce DNA-damage, whereas Fas ligation induces receptormediated apoptotic pathways. NSCLC cells were crossresistant to all treatments, whereas SCLC cells, which do not express pro-caspase-8, were resistant to aFas-, but not to DNA-damage-induced apoptosis. Cytochrome c release, activation of caspase-9 and the executioner caspase-3 were observed in both types of lung cancer cells. However, cleavage of known nuclear substrates for caspase-3, such as PARP and DFF45/ICAD, was documented only in the sensitive SCLC cells but not in the resistant NSCLC cells. Moreover, relocalization of active caspase-3 from the cytosol into the nucleus upon treatment was observed only in the SCLC cell line. These results indicate that the inhibition of apoptosis in NSCLC occurs downstream of mitochondrial changes and caspase activation, and upstream of nuclear events.

An increase in intracellular Ca2+ is required for the activation of mitochondrial calpain to release AIF during cell death

“…[11][12][13] However, the mechanisms by which AIF release is regulated have not yet been established conclusively. Therefore, in this study, we focused on the molecular mechanisms of AIF processing and release.…”

“…The human NSCLC cell line, U1810, used in this study has been previously investigated with regard to apoptosis susceptibility and resistance. 11,13 U1810 cells were grown in RPMI-1640 complete medium supplemented with 10% (v/v) heat-inactivated fetal bovine serum, 2% (w/v) glutamine, 100 U/ml penicillin and 100 U/ml streptomycin in a humidified 5% CO 2 atmosphere at 37 1C and were maintained at a cell density allowing exponential growth. Hepatoma HEK293 cells and neuroblastoma SH-SY5Y cells were grown in DMEM and MEM medium, respectively.…”

“…We have reported earlier that malfunction of AIF release from mitochondria is essential for the chemoresistance of U1810 NSCLC cells, as the activation of caspases alone was not sufficient to kill these cells. [11][12][13] However, we also found that staurosporine (STS) can reactivate the full apoptotic machinery in U1810 cells. This suggests an important function for the AIF-mediated cell death pathway in NSCLCs.…”

Opposing effects of hMOF and SIRT1 on H4K16 acetylation and the sensitivity to the topoisomerase II inhibitor etoposide

“…Human non-small-cell lung carcinoma cell line NCL-H157 (CRL-5802; ATCC, Manassas, VA, USA) and NCI-H1299 (CRL-5803; ATCC) and human neuroblastoma SK-N-BE(2) cell line (CRL-2271; ATCC) were used in this study (Joseph et al, 2001(Joseph et al, , 2002. None of the cell lines express functional p53: one is p53 null, one has a frameshift in p53 and the third has a p53 hot stop mutation (p53 mutation databases at http:// www-p53.iarc.fr and http://p53.free.fr).…”

Genome-wide siRNA Screen Identifies the Radiosensitizing Effect of Downregulation of MASTL and FOXM1 in NSCLC

“…The major division is made between small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), which make up 20% and 80% of the lung cancer cases, respectively (2). It has been shown that the different subtypes of lung cancer exhibit large variations in sensitivity to cytotoxic compounds and radiation, where SCLC was shown to be the most sensitive (3).…”