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PubMed2004

Endoplasmic reticulum stress initiates apoptotic death induced by STI571 inhibition of p210 bcr-abl tyrosine kinase.

The endoplasmic reticulum (ER) is the site where proteins destined to either secretion or different subcellular compartments assemble and the major storage of intracellular Ca(2+). The ER stress resulting from a variety of toxic insults leads to apoptosis. Here, we showed that the apoptotic death triggered by STI571, an inhibitor of the p210 bcr-abl tyrosine kinase, in murine myeloid progenitors transducing the p210 bcr-abl tyrosine kinase of Chronic Myeloid Leukemia (CML) proceeds from ER stress. The Bcl-2 dowmodulation and inactivation induced by the binding to its antagonist: Bad, the release of caspase 12 from the ER membranes in its active form and of Ca(2+) from the ER pool addressed towards ER a sensor of STI571-induced pro-apoptotic signal.

Animals↗
PubMed2004

Herp stabilizes neuronal Ca2+ homeostasis and mitochondrial function during endoplasmic reticulum stress.

In response to endoplasmic reticulum (ER) stress, cells launch homeostatic and protective responses, but can also activate cell death cascades. A 54 kDa integral ER membrane protein called Herp was identified as a stress-responsive protein in non-neuronal cells. We report that Herp is present in neurons in the developing and adult brain, and that it is regulated in neurons by ER stress; sublethal levels of ER stress increase Herp levels, whereas higher doses decrease Herp levels and induce apoptosis. The decrease in Herp protein levels following a lethal ER stress occurs prior to mitochondrial dysfunction and cell death, and is mediated by caspases which generate a 30-kDa proteolytic Herp fragment. Mutagenesis of the caspase cleavage site in Herp enhances its neuroprotective function during ER stress. While suppression of Herp induction by RNA interference sensitizes neural cells to apoptosis induced by ER stress, overexpression of Herp promotes survival by a mechanism involving stabilization of ER Ca(2+) levels, preservation of mitochondrial function and suppression of caspase 3 activation. ER stress-induced activation of JNK/c-Jun and caspase 12 are reduced by Herp, whereas induction of major ER chaperones is unaffected. Herp prevents ER Ca(2+) overload under conditions of ER stress and agonist-induced ER Ca(2+) release is attenuated by Herp suggesting a role for Herp in regulating neuronal Ca(2+) signaling. By stabilizing ER Ca(2+) homeostasis and mitochondrial functions, Herp serves a neuroprotective function under conditions of ER stress.

Amyloid beta-Peptides↗
PubMed2003

Inhibition of phosphatidylcholine synthesis induces expression of the endoplasmic reticulum stress and apoptosis-related protein CCAAT/enhancer-binding protein-homologous protein (CHOP/GADD153).

Inhibition of de novo synthesis of phosphatidylcholine (PC) by some anti-cancer drugs such as hexadecylphosphocholine leads to apoptosis in various cell lines. Likewise, in MT58, a mutant Chinese hamster ovary (CHO) cell line containing a thermo-sensitive mutation in CTP:phosphocholine cytidylyltransferase (CT), an important regulatory enzyme in the CDP-choline pathway, inhibition of PC synthesis causes PC depletion. Cellular perturbations like metabolic insults and unfolded proteins can be registered by the endoplasmic reticulum (ER) and result in ER stress responses, which can lead eventually to apoptosis. In this study we investigated the effect of PC depletion on the ER stress response and ER-related proteins. Shifting MT58 cells to the non-permissive temperature of 40 degrees C resulted in PC depletion via an inhibition of CT within 24 h. Early apoptotic features appeared in several cells around 30 h, and most cells were apoptotic within 48 h. The temperature shift in MT58 led to an increase of pro-apoptotic CCAAT/enhancer-binding protein-homologous protein (CHOP; also known as GADD153) after 16 h, to a maximum at 24 h. Incubation of wild-type CHO-K1 or CT-expressing MT58 cells at 40 degrees C did not induce differences in CHOP protein levels in time. In contrast, expression of the ER chaperone BiP/GRP78, induced by an increase in misfolded/unfolded proteins, and caspase 12, a protease specifically involved in apoptosis that results from stress in the ER, did not differ between MT58 and CHO-K1 cells in time when cultured at 40 degrees C. Furthermore, heat-shock protein 70, a protein that is stimulated by accumulation of abnormal proteins and heat stress, displayed similar expression patterns in MT58 and K1 cells. These results suggest that PC depletion in MT58 induces the ER-stress-related protein CHOP, without raising a general ER stress response.

Animals↗
PubMed2003

[Involvement of unfolded protein responses in neurodegeneration].

Various stresses cause the accumulation of unfolded proteins in the endoplasmic reticulum (ER). To manage the state, cells have the unfolded protein responses (UPR). If the UPR is unsuccessful, ER-mediated apoptosis occurs. To date, three types of UPR, i.e. the induction of chaperones, the translation block, and ER-associated degradation (ERAD) have been reported. To sense the accumulation of unfolded proteins, the ER has IRE1, PERK, and ATF6. The pathways mediated by IRE1 and ATF6 cause the induction of chaperones. The pathway mediated by PERK causes a translation block. The induction of caspase 12, the activation of the JNK pathway, and the induction of CHOP have been reported as apoptosis caused by ER stress. The stability of the cell is based on the balance between UPR and ER-mediated apoptosis. Recently several diseases have been reported to be related to ER stress. We reported that mutant presenilin 1 causes a vulnerability to ER stress because it attenuates the activation of IRE1, PERK, and ATF6. Recent reports have also shown that Parkinson disease and polyglutamine diseases are relevant to ER stress. Therefore it is suggested that the ER stress story is the common mechanism for neurodegerative disorders.

Activating Transcription Factor 6↗
PubMed2006

STI571 (Glivec) induces cell death in the gastrointestinal stromal tumor cell line, GIST-T1, via endoplasmic reticulum stress response.

STI571 is a specific inhibitor of tyrosine kinases, such as BCR-ABL, platelet-derived growth factor receptor, and c-KIT, and has recently been approved for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors (GISTs). This study demonstrated that STI571 induces cell death in the gastrointestinal stromal tumor cell line, GIST-T1. In these cells, STI571 induced pro-caspase-12 or pro-caspase-7 cleavage and it affected caspase-3 activity and induced the endoplasmic reticulum (ER)-resident chaperone, glucose-regulated protein 78. The STI571-induced cell death was blocked by the protein synthesis inhibitor, cycloheximide. Together, these results suggest that STI571 induces cell death in GIST-T1 cells, at least in part, via the ER stress response.

Antineoplastic Agents↗
PubMed2005

Age-related alterations in expression of apoptosis regulatory proteins and heat shock proteins in rat skeletal muscle.

Aging of skeletal muscle is often accompanied by muscle atrophy and it appears that apoptosis plays an important role in this process. The detailed mechanism(s) is not completely understood, however. In this study, we examined expression of the apoptosis regulatory proteins as well as the heat shock proteins, which have been shown to modulate the apoptotic process in certain cell types, in order to more completely elucidate apoptotic signaling in aged skeletal muscle. To more specifically identify alterations that are likely to be the result of aging, we compared 16-month-old middle-aged (MD) and 29-month-old senescent (SE) male Fischer 344 x Brown Norway rats in our study. Our results show that the degree of DNA laddering was higher in SE compared to MD rats. Using total tissue homogenates we examined the level of expression of several apoptosis-related proteins in two categories: mitochondria-associated proteins and caspases. Of the mitochondria-associated proteins, the levels of p53 showed a significant increase in SE compared to MD rats. There was also a significant increase in the expression of Bax, Bcl-2 and Apaf-1 in SE rats over that of MD rats; cytochrome c and AIF levels remained unchanged, however. Regarding the caspases, there were increases in the levels of pro-caspases-12 and -7 and cleaved caspase-9, although the levels of pro- and cleaved caspase-3 as well as cleaved caspase-12 remained unchanged. Furthermore, our results showed significant increases in HSP27, HSP60, and the inducible HSP70. These data show that in rat skeletal muscle increased apoptosis occurs between middle-age and senescence, indicating an aging-related increase in apoptosis in skeletal muscle. The involvement of different apoptotic pathways in the aging process is suggested by the selective alterations in the apoptosis regulatory proteins. The increased expression of the HSPs suggests a relationship between HSPs and the aging-related apoptotic process.

Aging↗
PubMed2005

Mitochondrial-mediated disregulation of Ca2+ is a critical determinant of Velcade (PS-341/bortezomib) cytotoxicity in myeloma cell lines.

The proteasome inhibitor bortezomib (also known as PS-341/Velcade) is a dipeptidyl boronic acid that has recently been approved for use in patients with multiple myeloma. Bortezomib inhibits the activity of the 26S proteasome and induces cell death in a variety of tumor cells; however, the mechanism of cytotoxicity is not well understood. In this report, oligonucleotide microarray analysis of the 8226 multiple myeloma cell line showed a predominant induction of gene products associated with the endoplasmic reticulum secretory pathway following short-term, high-dose exposure to bortezomib. Examination of mediators of endoplasmic reticulum stress-induced cell death showed specific activation of caspase 12, as well as of caspases 8, 9, 7, and 3, and cleavage of bid. Treatment of myeloma cells with bortezomib also showed disregulation of intracellular Ca2+ as a mechanism of caspase activation. Cotreatment with a panel of Ca2+-modulating agents identified the mitochondrial uniporter as a critical regulatory factor in bortezomib cytotoxicity. The uniporter inhibitors ruthenium red and Ru360 prevented caspase activation and bid cleavage, and almost entirely inhibited bortezomib-induced cell death, but had no effect on any other chemotherapeutic drug examined. Additional Ca2+-modulating agents, including 2-amino-ethoxydiphenylborate, 1,2-bis (o-aminophenoxy) ethane-tretraacetic acid (acetoxymethyl) ester, and dantrolene, did not alter bortezomib cytotoxicity. Analysis of intracellular Ca2+ showed that the ruthenium-containing compounds inhibited Ca2+ store loading and abrogated the desensitized capacitative calcium influx associated with bortezomib treatment. These data support the hypothesis that intracellular Ca2+ disregulation is a critical determinant of bortezomib cytotoxicity.

Antineoplastic Agents↗
PubMed2004

Mapping and transcription profiling of CASP1, 3, 6, 7 and 8 in relation to caspase activity in the bovine cumulus-oocyte complex.

So far 12 caspases have been described in mouse and human while only one (CASP13) is known in cattle. The aim of this study was to (1) search for other bovine caspases by reverse transcription and polymerase chain reaction (RT-PCR) and (2) examine the presence of bovine caspase mRNA and active protein in the cumulus-oocyte complex. Five caspases (1, 3, 6, 7 and 8) were identified, partially cloned and sequenced. Four of them were mapped. Differential transcription of the caspase genes was detected, but no active caspase protein was found in diverse bovine oocytes. Cumulus granulosa cells (CGC) contain CASP1, 6, 7 and 8 mRNA and active caspase protein. The presence of caspase mRNA and active caspase proteins in CGCs suggests the occurrence of apoptosis in cumulus-oocyte complex, while caspase activation is blocked in fresh oocytes and therefore caspase transcription cannot be used to predict the oocyte developmental capacity.

Animals↗
PubMed2003

Q-VD-OPh, a broad spectrum caspase inhibitor with potent antiapoptotic properties.

In recent years, several inhibitors that prevent caspase activation and apoptosis have emerged. At high doses, however, these inhibitors can have nonspecific effects and/or become cytotoxic. In this study, we determined the effectiveness of broad spectrum caspase inhibitors to prevent apoptosis. A carboxy terminal phenoxy group conjugated to the amino acids valine and aspartate (Q-VD-OPh) potently inhibited apoptosis. Q-VD-OPh was significantly more effective in preventing apoptosis than the widely used inhibitors, ZVAD-fmk and Boc-D-fmk, and was also equally effective in preventing apoptosis mediated by the three major apoptotic pathways, caspase 9/3, caspase 8/10, and caspase 12. In addition to the increased effectiveness, Q-VD-OPh was not toxic to cells even at extremely high concentrations. Our data indicate that the specificity, effectiveness, and reduced toxicity of caspase inhibitors can be significantly enhanced using carboxyterminal o-phenoxy groups and may have important uses in vivo.

Amino Acid Chloromethyl Ketones↗
PubMed2005

Emergence of endoplasmic reticulum stress and activated microglia in Purkinje cell degeneration mice.

In the current studies, we characterized the molecular and cellular mechanism of cell death in Purkinje cell degeneration (pcd) mice using real-time quantitative PCR, immunohistochemistry, and Western blotting. It appears that endoplasmic reticulum (ER) stress is involved in this degeneration of Purkinje cells because ER stress-related substrates, such as CHOP and caspase 12, were strongly activated in Purkinje cells of pcd mice during the third postnatal (P) week. A significant increase in the expression of the ER-specific chaperone BiP suggested that unfolded protein responses were induced. We also found that Purkinje cells underwent apoptosis via the activation of caspase 3 and subsequent fragmentation of DNA. In addition to the activation of apoptosis in Purkinje cells, many activated microglial cells are found to be present in the molecular layer of the cerebellar cortex. In the later phase of degeneration, there was conspicuous expression of inducible nitric oxide synthase (iNOS), and some Purkinje cells were strongly labeled with an antibody to nitrotyrosine, suggesting that Purkinje cells in pcd mice are damaged by nitric oxide released from microglial cells. Administration of minocycline, which may inhibit iNOS expression, delayed the death of Purkinje cells in pcd mice and mildly improved their motor abilities. These findings suggest that ER stress participates in the degeneration of Purkinje cells and that activation of microglia accelerates Purkinje cell death in pcd mice.

Animals↗
PubMed2005

Tumor response to neoadjuvant chemoradiation therapy for rectal adenocarcinoma is mediated by p53-dependent and caspase 8-dependent apoptotic pathways.

BACKGROUND: We tested the hypothesis that rectal tumors are most responsive to neoadjuvant therapy if they possess p53 and/or caspase 8 activity. PATIENTS AND METHODS: Fifty patients diagnosed with biopsy-proven rectal cancer underwent neoadjuvant chemoradiation therapy consisting of 5-fluorouracil (300 mg/m(2) daily) and radiation (4,500 cGy). Endorectal ultrasonography was performed before and after neoadjuvant therapy along with digital rectal examination and/or sigmoidoscopy for staging purposes and to evaluate response to therapy. All patients underwent resection with specimens submitted for gross and microscopic review. Pretreatment biopsy specimens were subjected to immunohistochemical staining for mutated p53 and caspase 8 bioactivity. RESULTS: The study population consisted of 32 men and 18 women. There were 17 complete responses (CRs; 34%), 17 partial responses (PRs; 34%), and 16 cases of no response (NR; 32%). There were 10 stage I tumors (20%), 22 stage II tumors (44%), and 18 stage III tumors (36%) in the cohort at the time of initial diagnosis. p53 protein staining (ie, mutated p53) was positive in 31 tumors (62%; CR, n = 8; PR, n = 11; NR, n = 12); caspase 8 positivity was apparent in 30 specimens (60%; CR, n = 13; PR, n = 13; NR, n = 4). In terms of pretreatment predictions, we scored 3 separate levels of response (CR, 3; PR, 2; NR, 1) and compared them with the expected responses (ie, p53 positivity and caspase 8 negativity should yield NR, whereas all other combinations should yield responses). Wilcoxon 2-sample tests yielded a 1-sided P value of 0.007. CONCLUSION: The present study highlights a possible mechanism for tumor response to neoadjuvant manipulation, namely that dual mechanisms for apoptotic cell death are working in concert to cause tumor regression; one is p53 transcription-dependent, and the other is p53 transcription-independent.

Adenocarcinoma↗
PubMed2005

Ester derivatives of tournefolic acid B attenuate N-methyl-D-aspartate-mediated excitotoxicity in rat cortical neurons.

The effects of tournefolic acid B (TAB) and two ester derivatives, TAB methyl ester (TABM) and TAB ethyl ester (TABE), on N-methyl-D-aspartate (NMDA)-mediated excitotoxicity and the underlying mechanisms were investigated. Treatment with 50 microM NMDA elicited neuronal death by 48.7 +/- 5.1%, coinciding with the appearance of injured morphology. TABM (50 microM) attenuated the NMDA-induced cell death by 60.9 +/- 19.7%, and to a lesser extent by TABE. The NMDA-mediated activation of calpain was not affected by TABM and TABE, as determined by the cleavage of alpha-spectrin. NMDA increased the activity of caspases 2, 3, 6, 8, and 9 and reached the maximum after 8-h treatment. TABM and TABE abrogated NMDA-induced activation of caspases 2, 3, 6, and 8 by approximately 80 to 90% and 50 to 60%, respectively, and to a higher extent for caspase 9. TABM and TABE also blocked the NMDA-mediated activation of caspase 12. Furthermore, TABM and TABE eliminated the NMDA-induced accumulation of superoxide anion (O2-*). NMDA evoked significant depolarization of mitochondria, whereas TABM elicited a mild decrease of mitochondrial membrane potential as determined by tetramethylrhodamine methyl ester perchlorate. NMDA treatment induced elevation of Ca2+ levels in cytosol, endoplasmic reticulum (ER), and mitochondria. TABM (50 microM) significantly diminished the NMDA-induced elevation of Ca2+ levels in mitochondria and ER but not cytosol. Therefore, TABM decreased mitochondrial membrane potential and attenuated the NMDA-mediated Ca2+-loading in ER and mitochondria. These events subsequently eliminated the accumulation of O2-* and blocked the activation of caspase cascade, thereby conferring their neuroprotective effects on NMDA-mediated excitotoxicity.

Animals↗
PubMed2001

An endoplasmic reticulum-specific stress-activated caspase (caspase-12) is implicated in the apoptosis of A549 epithelial cells by respiratory syncytial virus.

Respiratory syncytial virus (RSV) infection induced programmed cell death or apoptosis in the cultured lung epithelial cell line, A549. The apoptotic cells underwent multiple changes, including fragmentation and degradation of genomic DNA, consistent with the activation of the DNA fragmentation factor or caspase-activated DNase (DFF or CAD). The infection led to activation of FasL; however, a transdominant mutant of FAS-downstream death domain protein, FADD, did not inhibit apoptosis. Similarly, modest activation of cytoplasmic apoptotic caspases, caspase-3 and -8, were observed; however, only a specific inhibitor of caspases-3 inhibited apoptosis, while an inhibitor of caspase-8 had little effect. No activation of caspase-9 and -10, indicators of the mitochondrial apoptotic pathway, was observed. In contrast, RSV infection strongly activated caspase-12, an endoplasmic reticulum (ER) stress response caspase. Activation of the ER stress response was further evidenced by upregulation of ER chaperones BiP and calnexin. Antisense-mediated inhibition of caspase-12 inhibited apoptosis. Inhibitors of NF-kappa B had no effect on apoptosis. Thus, RSV-induced apoptosis appears to occur through an ER stress response that activates caspase-12, and is uncoupled from NF-kappa B activation.

Apoptosis↗
PubMed2002

Presenilin-1 mutations sensitize neurons to DNA damage-induced death by a mechanism involving perturbed calcium homeostasis and activation of calpains and caspase-12.

Mutations in presenilin-1 (PS1) can cause early onset familial Alzheimer's disease (AD). Studies of cultured cells and mice expressing mutant PS1 suggest that PS1 mutations may promote neuronal dysfunction and degeneration by altering cellular calcium homeostasis. On the other hand, it has been suggested that age-related damage to DNA in neurons may be an important early event in the pathogenesis of AD. We now report that PC12 cells and primary hippocampal neurons expressing mutant PS1 exhibit increased sensitivity to death induced by DNA damage. The hypersensitivity to DNA damage is correlated with increased intracellular Ca(2+) levels, induction of p53, upregulation of the Ca(2+)-dependent protease m-calpain, and mitochondrial membrane depolarization. Moreover, activation of caspase-12, an endoplasmic reticulum (ER)-associated caspase, is greatly increased in cells expressing mutant PS1. DNA damage-induced death of cells expressing mutant PS1 was attenuated by inhibitors of calpains I and II, by an intracellular Ca(2+) chelator, by the protein synthesis inhibitor cycloheximide, and by a broad-spectrum caspase inhibitor, but not by an inhibitor of caspase-1. Agents that release Ca(2+) from the ER increased the vulnerability of cells expressing mutant PS1 to DNA damage. By promoting ER-mediated apoptotic proteolytic cascades, PS1 mutations may sensitize neurons to DNA damage.

Alzheimer Disease↗
PubMed2003

Coupling endoplasmic reticulum stress to cell death program in isolated human pancreatic islets: effects of gene transfer of Bcl-2.

A variety of toxic insults can result in endoplasmic reticulum (ER)-stress that ultimately leads to apoptosis. beta-cells have a highly developed ER due to a great commitment to insulin production. The present study was carried out to determine the role of ER-stress in isolated human pancreatic islet apoptosis, and the potential protective effects of Bcl-2. Isolated human islets were infected with an adenoviral vector encoding Bcl-2 and then exposed to brefeldin-A, tunicamycin, A23187 and pro-inflammatory cytokines. Activation of caspase-12 was analyzed by means of Western blots. Apoptosis was evaluated using a commercial quantitative assay. ER-stress-inducers promoted caspase-12 activation and apoptosis, effect reversed by overexpression of Bcl-2. Co-localization of caspase-12 and Bcl-2 in the microsomal islet fractions were demonstrated by means of Western blots. We can conclude that the current studies highlight the importance of Bcl-2 as an anti-apoptotic protein, and shed new light on the mechanisms underlying its cytoprotective effects on pancreatic islets.

Apoptosis↗
PubMed2004

Genistein induces Ca2+ -mediated, calpain/caspase-12-dependent apoptosis in breast cancer cells.

Genistein, a soy-derived isoflavone, has been suggested for breast cancer prevention; however, use of soy products for this purpose remains controversial. Genistein has been reported to regulate growth of tumor cells, although the involved molecular mechanisms are not defined. Here we report that genistein induces apoptosis in breast cancer cells via activation of the Ca2+ -dependent proapoptotic proteases, mu-calpain, and caspase-12. The treatment of MCF-7 breast cancer cells with genistein induced a sustained increase in concentration of intracellular Ca2+ resulting from depletion of the endoplasmic reticulum Ca2+ stores. This increase in Ca2+ was associated with activation of mu-calpain and caspase-12, as evaluated with the calpain and caspase-12 substrates and antibodies to active (cleaved) forms of the enzymes. Selective inhibition of Ca2+ binding sites of mu-calpain, forced increase of the cytosolic Ca2+ buffering capacity, and caspase inhibition decreased apoptotic indices in the genistein-treated cells. Our results suggest that Ca2+ -dependent proteases are potential targets for genistein in breast cancer cells and that the cellular Ca2+ regulatory activity of genistein underlies its apoptotic mechanism.

Apoptosis↗
PubMed2004

Caspase-12 cleavage and increased oxidative stress during motoneuron degeneration in transgenic mouse model of ALS.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by loss of motoneurons in the spinal cord and brain stem. We have characterized motoneuron death in transgenic mice carrying the mutant human copper/zinc superoxide dismutase, as a model for familial ALS. Previous studies have shown the involvement of mitochondria in nerve cell demise in these animals. We report here an early cleavage of caspase-12, residing in the endoplasmic reticulum (ER), in the spinal cord during the course of the disease. Apart from caspase-12, caspase-9, and caspase-3 were activated in the transgenic ALS mice. Staining with an antibody for nitrotyrosine, as a marker for oxidative stress, showed a large increase in the ALS mice. The results indicate that oxidative and ER induced stress causing caspase-12 activation are involved in neuronal death and disease progression in ALS. Caspase-12 and the ER pathway for cell death may constitute potential novel targets for the treatment of ALS.

Adaptation, Physiological↗
PubMed2006

TNF-alpha-mediated cardiomyocyte apoptosis involves caspase-12 and calpain.

Following ischemia-reperfusion, there is a sustained increase of TNF-alpha both locally in the heart as well as in circulating levels in blood. While TNF-alpha has been implicated in cardiomyocyte apoptosis which occurs in several cardiomyopathies, the molecular pathways by which TNF-alpha induces apoptosis in these cells are not fully elucidated. We investigated the role of the two families of cysteine proteases, caspases and calpains, which are known to participate in apoptotic cell death. The effect of the highly specific calpain inhibitor, Z-LLY-fmk, and the caspase pathways involved in TNF-alpha-mediated apoptosis of the HL-1 cardiomyocyte cell line were examined. Activation of the downstream caspase-3, and the cleavage of poly ADP-ribose polymerase (PARP) were observed in a time-dependent manner upon treatment with TNF-alpha. Caspase-12, but not caspase-9, was activated in response to TNF-stimulation, indicating that an endoplasmic reticulum (ER)/calcium-dependent pathway may be involved. In HL-1 cardiomyocytes, TNF-alpha-induced apoptosis appears to be mediated by calpain as apoptotic changes were abrogated in the presence of the highly specific calpain inhibitor, Z-LLY-fmk. In conclusion, our results suggest that TNF-alpha-mediated apoptosis in HL-1 cardiomyocytes follows the caspase-12 apoptotic pathway that involves calpain.

Animals↗