Apoptosis: friend or foe?

Papaverine Enhances the Oncolytic Effects of Newcastle Disease Virus on Breast Cancer In Vitro and In Vivo

Breast cancer is a lethal disease in females worldwide and needs effective treatment. Targeting cancer cells with selective and safe treatment seems like the best choice, as most chemotherapeutic drugs act unselectively. Papaverine showed promising antitumor activity with a high safety profile and increased blood flow through vasodilation. At the same time, it was widely noticed that virotherapy using the Newcastle disease virus proved to be safe and selective against a broad range of cancer cells. Furthermore, combination therapy is favorable, as it attacks cancer cells with multiple mechanisms and enhances virus entrance into the tumor mass, overcoming cancer cells' resistance to therapy. Therefore, we aimed at assessing the novel combination of the AMHA1 strain of Newcastle disease virus (NDV) and nonnarcotic opium alkaloid (papaverine) against breast cancer models in vitro and in vivo. Methods. In vitro experiments used two human breast cancer cell lines and one normal cell line and were treated with NDV, papaverine, and a combination. The study included a cell viability MTT assay, morphological analysis, and apoptosis detection. Animal experiments used the AN3 mouse mammary adenocarcinoma tumor model. Evaluation of the antitumor activity included growth inhibition measurement; the immunohistochemistry assay measured caspase protein expression. Finally, a semiquantitative microarray assay was used to screen changes in apoptotic proteins. In vitro, results showed that the combination therapy induces synergistic cytotoxicity and apoptosis against cancer cells with a negligible cytotoxic effect on normal cells. In vivo, combination treatment induced a significant antitumor effect with an obvious regression in tumor size and a remarkable and significant expression of caspase-3, caspase-8, and caspase-9 compared to monotherapies. Microarray analysis shows higher apoptosis protein levels in the combination therapy group. In conclusion, this study demonstrated the role of papaverine in enhancing the antitumor activity of NDV, suggesting a promising strategy for breast cancer therapy through nonchemotherapeutic drugs.

The Roles of Apoptosis in Swine Response to Viral Infection and Pathogenesis of Swine Enteropathogenic Coronaviruses

Apoptosis is a tightly regulated mechanism of cell death that plays important roles in various biological processes including biological evolution, multiple system development, anticancer, and viral infections. Swine enteropathogenic coronaviruses invade and damage villous epithelial cells of the small intestine causing severe diarrhea with high mortality rate in suckling piglets. Transmissible gastroenteritis virus (TGEV), Porcine epidemic diarrhea virus (PEDV), Porcine deltacoronavirus (PDCoV), and Swine acute diarrhea syndrome coronavirus (SADS-CoV) are on the top list of commonly-seen swine coronaviruses with a feature of diarrhea, resulting in significant economic losses to the swine industry worldwide. Apoptosis has been shown to be involved in the pathogenesis process of animal virus infectious diseases. Understanding the roles of apoptosis in host responses against swine enteropathogenic coronaviruses infection contribute to disease prevention and control. Here we summarize the recent findings that focus on the apoptosis during swine coronaviruses infection, in particular, TGEV, PEDV, PDCoV, and SADS-CoV.

Biomarkers assessing warm ischemic injury using an isolated porcine kidney hemoreperfusion model

Prolonged warm ischemia (WI) occurring in marginal kidney donors together with reperfusion injury determines allograft survival, in which apoptosis and inflammation play crucial roles. There is no single valid biomarker, so far, to assess the degree of kidney donor injury. To define new biomarkers for detecting initial donor ischemic injury, caspase-3, caspase-7, apoptosis, inflammation, HSP70 and renal histological changes were examined in porcine kidneys subjected to 7- 15- 25- or 40-min WI, two-hour cold storage and six-hour hemoreperfusion. Caspase-3 activity was gradually increased by prolonged reperfusion, with a decrease trend against WI time. This result was verified by raised 17 kDa active caspase-3 in postreperfusion kidneys, with elevated 12 kDa active caspase-3 and lowered precursor at seven-minute WI. Active caspase-7 was also doubled by reperfusion with decreased precursor at seven-minute WI, but declined against prolonged WI. Apoptotic cells in tubular and interstitial areas were greatly increased by reperfusion at seven-minute WI, but decreased against prolonged WI. In addition, myeloperoxidase (MPO)+ cells were dramatically increased by reperfusion and presented as a bell-shape against WI time, while HSP70 was significantly increased at 7-min WI, but decreased at 40-min WI after reperfusion. In postreperfusion kidneys, tubular dilation and cell shedding were observed at 7- and 15-min WI, while tubular vacuolation and cell debris were found in tubular lumens at longer WI times. At 40-min WI, early nuclear pyknosis, tubular epithelia detachment and peri-tubular capillary dilation were detected. Furthermore, caspase-3, caspase-7, apoptosis, but not MPO+ cells or HSP70, were correlated with renal function. In conclusion, caspase-3, caspase-7 and apoptosis appear to be better biomarkers than MPO+ cells or HSP70 for assessing warm ischemic injury in donor kidneys. Hemoreperfusion activates caspase-3 and caspase-7, promotes apoptosis of damaged cells in kidneys only with limited WI, which might be beneficial to renal structural re-modeling and functional recovery.

Effects of zinc on programmed cell death of Musca domestica and Drosophila melanogaster blood cells

Programmed cell death (PCD) and phagocytotic activity of immune cells play a pivotal role in insect development. We examined the influence of Zn(2+), an important element to fundamental biological processes, on phagocytosis and apoptosis of hemocytes in two fly species: Musca domestica and Drosophila melanogaster. Hemocytes were isolated from the third instar larvae of both species and treated for 3h with zinc chloride solutions, containing 0.35 mM or 1.7 mM of Zn(2+), and untreated as control. Phagocytotic activity of hemocytes was examined by flow cytometry after adding latex fluorescent beads to the medium, while apoptosis was evaluated by application of annexinV-FITC and pan-caspase-FITC inhibitor. Mitochondrial viability was determined by measuring resazurin absorbancy in the cell medium. The obtained results showed that Zn(2+) increases phagocytosis and affects PCD of both species hemocytes but each in a different way. Zinc decreases fraction of annexin-positive hemocytes in M. domestica but increases it in D. melanogaster. The pan-caspase analysis revealed low and high activity of caspases in hemocytes of M. domestica and D. melanogaster, respectively. Zn(2+) also decreased the viability of hemocyte mitochondria but only in D. melanogaster. It suggests that flies use different pathways of PCD, or that Zn plays a different role in this process in M. domestica than in D. melanogaster.

Apoptosis and Caspase-3 in Long-Term Renal Ischemia/Reperfusion Injury in Rats and Divergent Effects of Immunosuppressants

BACKGROUND

Caspase-3 plays a key role in apoptosis, but the involvement of apoptosis and caspase-3 in mediating long-term ischemia/reperfusion (I/R) and immunosuppressive injury are not fully defined. The present study was undertaken to investigate apoptosis and caspase-3 in a renal I/R injury rat model with or without immunosuppression.

METHODS

The right renal pedicle was clamped for 45 minutes and left nephrectomy was induced. Cyclosporin A (CsA), tacrolimus (Tac), rapamycin (Rap), or mycophenolate mofetil (MMF) were administered daily. Animals were killed at 16 weeks, and the levels of apoptosis (with in situ end-labeling fragmented DNA), caspase-3 protein (with immunohistochemistry, Western blotting, and activity assay), and messenger RNA (mRNA; with quantitative reverse-transcriptase polymerase chain reaction) were evaluated.

RESULTS

Kidneys with I/R injury showed increased apoptosis in tubular and interstitial areas compared with control kidneys. Tacrolimus, Rap, and MMF significantly reduced apoptosis, but CsA did not. Distribution of full-length caspase-3 widened in I/R-injured kidneys from normal distal tubules and collecting ducts to dilated proximal tubules and expanded interstitium, whereas active caspase-3 was mainly scattered in damaged tubules and interstitium. Active caspase-3 staining and 24-kDa active caspase-3 protein was enhanced in I/R-injured and CsA-treated kidneys, but decreased by Tac, Rap, and MMF. These results were also consistent with changes in caspase-3 activity. Although caspase-3 mRNA levels were significantly increased in uninephrectomy and I/R-injured kidneys, they were not significantly affected by the immunosuppressants. In addition, all changes detected were positively correlated with renal structure and function.

CONCLUSION

Apoptosis and caspase-3 are not only involved in the long-term renal I/R injury, but also mediate the divergent effects of immunosuppression in this model.

Molecular effects of cyclosporine and oncogenesis: a new model

Cyclosporine A is the most commonly used immunosuppressive agent during organ transplantation. One of the most feared adverse effects of cyclosporine A is the appearance of de novo cancers. The mechanisms that lead to the genesis of such cancers are thought to be only related to a side effect of cyclosporine A: a depressed immune system. Here, we review different molecular effects induced by cyclosporine A (inhibition of DNA repair, synthesis of TGF Beta, induction of apoptosis of activated T cells, inhibition of apoptosis through the inhibition of the opening of the mitochondrial Permeability Transition Pore) and propose that cyclosporine A can promote the genesis and the spread of cancer not only because of immunosuppression but also because of its ability to facilitate DNA mutations accumulation, to diminish the clearance of altered cells and to transform cancer cells into aggressive cancer cells. This new insights into the mechanisms of genesis of cyclosporine A-related cancers should be taken into account to develop preventive strategies or new immunosuppressive strategies.