Alterations of cellular organelles in human liver-derived hepatoma G2 cells induced by adriamycin

Abstract

Adriamycin (ADM) is a commonly used chemotherapeutic drug in the treatment of hepatocellular carcinoma. However, the mechanisms involved in ADM-induced cell death and the molecular basis of ADM resistance are still unclear. To observe the early events that occurred in hepatoma cells in response to ADM, we investigated the alterations of morphology and subcellular distributions of cellular organelles in human liver-derived hepatoma G2 (HepG2) cells after ADM treatment. HepG2 cells were exposed to different doses of ADM for up to 60 h. Cytotoxicity occurred 24 h after 0.05 microg/ml ADM application, and remaining living cells showed irregular shapes but continued to multiply. Some cellular organelles altered their subcellular distribution or morphology after ADM treatment, including mitochondria, autophagic vacuoles, and Golgi apparatus. Immunoblotting with anti-LC3 antibody showed the upregulation of LC3-II protein, confirming that ADM leads to the induction of autophagy in HepG2 cells. Our findings suggest that among most of the cellular organelles, mitochondria and autophagic vacuoles were involved in the early ADM response, and may contribute to ADM-induced HepG2 cell death.

DNA Damage Triggers Golgi Dispersal via DNA-PK and GOLPH3

“…Since changes in Golgi morphology have been reported to occur during apoptosis (Chiu et al, 2002; Jung et al, 2006; Lane et al, 2002; Mancini et al, 2000; Qian and Yang, 2009), we examined whether DNA-damage-induced Golgi dispersal occurs as a consequence of apoptosis. Although treatment with CPT caused a significant increase in the number of apoptotic cells (Figures 2C and 2D), still only a small fraction of cells became apoptotic (1.74% ± 0.08% [mean ± SEM] positive for cleaved caspase-3 (CCasp-3), coinciding with other morphological evidence of apoptosis, such as pyknotic nuclei, fragmented nuclei, or plasma membrane [PM] blebbing).…”

“…The effect of DNA damage on the Golgi has been largely neglected in the literature, with a few prior hints of an effect generally being ascribed to a consequence of DNA-damage-induced apoptosis (Chiu et al, 2002; Jung et al, 2006; Lane et al, 2002; Mancini et al, 2000; Qian and Yang, 2009). The induction of Golgi dispersal by even minimally toxic doses of DNA-damaging agents, the continued apparent health of cells observed by time-lapse microscopy, and the persistence of the Golgi dispersal for weeks all demonstrate that the Golgi response is unrelated to apoptosis.…”

The Autophagy-Senescence Connection in Chemotherapy: Must Tumor Cells (Self) Eat Before They Sleep?

“…Our previous studies as well as others have established the capacity of Adriamycin to promote premature or accelerated senescence in tumor cells (Chang et al, 1999;Elmore et al, 2002;Di et al, 2009;Gewirtz, 2009), whereas a number of studies have indicated that ADR also promotes autophagy Qian and Yang, 2009). We have postulated that both autophagy and senescence may represent efforts by the tumor cell to evade drug or radiation-induced toxicity (Gewirtz, 2009), and it is well established that different modes of cell death may coexist in the same cancer cell population in response to genotoxic stress Jinno-Oue et al, 2010).…”

“…In addition, previous studies in thyroid cancer and hepatoma cells have demonstrated that Adriamycin can induce autophagy (Lin et al, 2009;Qian and Yang, 2009). Although senescence and autophagy are generally considered to be two distinct cellular events in response to genotoxic stress, there has been accumulating evidence that the two are functionally intertwined (Gerland et al, 2003;Patschan et al, 2008;Gosselin et al, 2009;Jinno-Oue at al., 2010).…”

Iron Chelators with Topoisomerase-Inhibitory Activity and Their Anticancer Applications

“…Lovejoy et al have proposed that since autophagic pathways are abnormal in cancer cells by virtue of monoallelic deletion of the autophagic regulator, beclin1, apoptosis, and cell death would be the favored pathway in cancer cells (156). Doxorubicin also induces autophagy as one of its cellular responses (205). This has been exploited with the autophagy inhibitor, resveratol, to attenuate the cardiotoxic effects of doxorubicin (289).…”