Zinc protoporphyrin IX, a heme oxygenase-1 inhibitor, demonstrates potent antitumor effects but is unable to potentiate antitumor effects of chemotherapeutics in mice

<p>Abstract</p> <p>Background</p> <p>HO-1 participates in the degradation of heme. Its products can exert unique cytoprotective effects. Numerous tumors express high levels of HO-1 indicating that this enzyme might be a potential therapeutic target. In this study we decided to evaluate potential cytostatic/cytotoxic effects of zinc protoporphyrin IX (Zn(II)PPIX), a selective HO-1 inhibitor and to evaluate its antitumor activity in combination with chemotherapeutics.</p> <p>Methods</p> <p>Cytostatic/cytotoxic effects of Zn(II)PPIX were evaluated with crystal violet staining and clonogenic assay. Western blotting was used for the evaluation of protein expression. Flow cytometry was used to evaluate the influence of Zn(II)PPIX on the induction of apoptosis and generation of reactive oxygen species. Knock-down of HO-1 expression was achieved with siRNA. Antitumor effects of Zn(II)PPIX alone or in combination with chemotherapeutics were measured in transplantation tumor models.</p> <p>Results</p> <p>Zn(II)PPIX induced significant accumulation of reactive oxygen species in tumor cells. This effect was partly reversed by administration of exogenous bilirubin. Moreover, Zn(II)PPIX exerted potent cytostatic/cytotoxic effects against human and murine tumor cell lines. Despite a significant time and dose-dependent decrease in cyclin D expression in Zn(II)PPIX-treated cells no accumulation of tumor cells in G1 phase of the cell cycle was observed. However, incubation of C-26 cells with Zn(II)PPIX increased the percentage of cells in sub-G1 phase of the cells cycle. Flow cytometry studies with propidium iodide and annexin V staining as well as detection of cleaved caspase 3 by Western blotting revealed that Zn(II)PPIX can induce apoptosis of tumor cells. B16F10 melanoma cells overexpressing HO-1 and transplanted into syngeneic mice were resistant to either Zn(II)PPIX or antitumor effects of cisplatin. Zn(II)PPIX was unable to potentiate antitumor effects of 5-fluorouracil, cisplatin or doxorubicin in three different tumor models, but significantly potentiated toxicity of 5-FU and cisplatin.</p> <p>Conclusion</p> <p>Inhibition of HO-1 exerts antitumor effects but should not be used to potentiate antitumor effects of cancer chemotherapeutics unless procedures of selective tumor targeting of HO-1 inhibitors are developed.</p

Low dose of GRP78-targeting subtilase cytotoxin improves the efficacy of photodynamic therapy in vivo

Photodynamic therapy (PDT) exerts direct cytotoxic effects on tumor cells, destroys tumor blood and lymphatic vessels and induces local inflammation. Although PDT triggers the release of immunogenic antigens from tumor cells, the degree of immune stimulation is regimen-dependent. The highest immunogenicity is achieved at sub-lethal doses, which at the same time trigger cytoprotective responses, that include increased expression of glucose-regulated protein 78 (GRP78). To mitigate the cytoprotective effects of GRP78 and preserve the immunoregulatory activity of PDT, we investigated the in vivo efficacy of PDT in combination with EGF-SubA cytotoxin that was shown to potentiate in vitro PDT cytotoxicity by inactivating GRP78. Treatment of immunocompetent BALB/c mice with EGF-SubA improved the efficacy of PDT but only when mice were treated with a dose of EGF-SubA that exerted less pronounced effects on the number of T and B lymphocytes as well as dendritic cells in mouse spleens. The observed antitumor effects were critically dependent on CD8(+) T cells and were completely abrogated in immunodeficient SCID mice. All these results suggest that GRP78 targeting improves in vivo PDT efficacy provided intact T-cell immune system

Photodynamic Therapy of Tumors Can Lead to Development of Systemic Antigen-Specific Immune Response

Background: The mechanism by which the immune system can effectively recognize and destroy tumors is dependent on recognition of tumor antigens. The molecular identity of a number of these antigens has recently been identified and several immunotherapies have explored them as targets. Photodynamic therapy (PDT) is an anti-cancer modality that uses a non-toxic photosensitizer and visible light to produce cytotoxic reactive oxygen species that destroy tumors. PDT has been shown to lead to local destruction of tumors as well as to induction of anti-tumor immune response. Methodology/Principal Findings: We used a pair of equally lethal BALB/c colon adenocarcinomas, CT26 wild-type (CT26WT) and CT26.CL25 that expressed a tumor antigen, β-galactosidase (β-gal), and we treated them with vascular PDT. All mice bearing antigen-positive, but not antigen-negative tumors were cured and resistant to rechallenge. T lymphocytes isolated from cured mice were able to specifically lyse antigen positive cells and recognize the epitope derived from beta-galactosidase antigen. PDT was capable of destroying distant, untreated, established, antigen-expressing tumors in 70% of the mice. The remaining 30% escaped destruction due to loss of expression of tumor antigen. The PDT anti-tumor effects were completely abrogated in the absence of the adaptive immune response. Conclusion: Understanding the role of antigen-expression in PDT immune response may allow application of PDT in metastatic as well as localized disease. To the best of our knowledge, this is the first time that PDT has been shown to lead to systemic, antigen- specific anti-tumor immunity.United States. National Cancer Institute (grant RO1CA/AI838801)United States. National Cancer Institute (grant R01AI050875

Practicing motorcyle sport in the context of indirect self-destruction and risky behavior

Tematem mojej pracy jest „Uprawianie sportów motocyklowych w kontekście autodestrukcji pośredniej oraz zachowań ryzykownych”. Celem niniejszej pracy dyplomowej było przede wszystkim wykazanie czy mężczyźni uprawiający sporty motocyklowe charakteryzują się wysokim poziomem autodestrukcji pośredniej. Ponadto przedstawiona została także szeroko problematyka podejmowania zachowań ryzykownych u motocyklistów. Zajmując się autodestrukcją pośrednią oraz zachowaniami ryzykownymi odniesiono się także do tego jaki wpływ na te zmienne mają wiek, stan cywilny, samoocena oraz obraz własnego ciała motocyklistów. W badaniu wzięło udział 60 mężczyzn motocyklistów. Badani przydzieleni zostali do dwóch grup wiekowych: 18-30 lat oraz 31-50 lat. W obu grupach znalazło się po 30 mężczyzn. Do przeprowadzenia badania zostało użytych 5 testów psychologicznych oraz kwestionariusz osobowy stworzony samodzielnie. Testy psychologiczne użyte w badaniu to: Skala Chronicznej Autodestrukcyjności Kelly – do badania pośredniej autodestrukcji, Wieloczynnikowa Skala Zachowań Ryzykownych – do badania częstości podejmowania zachowań ryzykownych, Skala zaangażowania wobec ciała BIS – do badania obrazu własnego ciała, Skala odczuć wobec własnej osoby i poczucia własnej kompetencji oraz Skala samooceny Rosenberga – obie do badania poziomu samooceny.Wyniki przeprowadzonych badań wykazały, że mężczyźni uprawiający sporty motocyklowe charakteryzują się przeciętnym poziomem zarówno autodestrukcji pośredniej jak i zachowań ryzykownych. Wykazano jednak różnice w natężeniu badanych zmiennych w zależności od wieku badanych. Odnotowano, że mężczyźni z przedziału wiekowego 18-30 uzyskiwali wyższe wyniki od mężczyzn z grupy 31-50, zarówno w autodestrukcji pośredniej jak i w podejmowaniu zachowań ryzykownych. Dzięki przeprowadzonym badaniom wykryto także związek pomiędzy stanem cywilnym a podejmowaniem zachowań ryzykownych przez motocyklistów. Okazało się, że motocykliści kawalerowie częściej podejmują zachowania ryzykownych od motocyklistów żonatych. Istotny także okazał się związek autodestrukcji pośredniej z zachowaniami ryzykownymi. Wyniki badań dowiodły, że motocykliści częściej podejmujący zachowania ryzykowne będą charakteryzować się wyższym poziomem autodestruktywności pośredniej.The subject of my work is "The practice of motorcycle sports in the context of indirect self-destruction and risky behavior." The aim of this thesis was primarily to show whether motorbike men are characterized by a high level of indirect self-destruction. In addition, the issue of risk behavior in motorcyclists is also widely presented. When dealing with indirect self-destruction and risky behaviors, the impact on these variables is also related to age, marital status, self-esteem and the image of the body of a motorcyclist. The study was attended by 60 male bikers. The respondents were assigned to two age groups: 18-30 years and 31-50 years old. Both groups included 30 men. Five psychological tests and a personal questionnaire were used for the study. The psychological tests used in the study are: Kelly Chronic Self-Efficacy Scale - for indirect self-destructive testing, Multivariable Risk Behavior Scale - to investigate the frequency of risky behavior, BIS engagement scale, self-image scale, self-perception and self-esteem And Rosenberg's Self-Esteem Scale - both for self-assessment. The results of the study showed that men who practice motorbike sports are characterized by the average level of both self-destruction and risky behavior. However, differences in the intensity of the variables tested were found, depending on the age of the subjects. It was reported that men in the 18-30 age range were higher on 31-50 men in both self-destruct and risky behavior. The study also found a link between civil status and risky behavior by motorcyclists. It turned out that bachelor bikers often take risky behaviors from married bikers. The relationship between self-destruction and risky behavior has also been significant. The results of the study have shown that motorcyclists more likely to engage in risky behaviors will have a higher level of self-destructiveness

Combination of photodynamic therapy with aspirin in human-derived lung adenocarcinoma cells affects proteasome activity and induces apoptosis.

OBJECTIVES: Photodynamic treatment (PDT) of human lung carcinoma cells A549 (p53(+/+)) and H1299 (p53(-/-)) induces fast but transient stalling of proteasome activity. We have explored the possibility of prolonging this effect by combining PDT with drugs capable of sustaining the stall, and promote apoptosis of surviving cells. We show that aspirin can be used to accomplish this. MATERIALS AND METHODS: Cells were irradiated at doses ranging from 0.54 to 1.10 J cm(-2), and subsequently were incubated with aspirin at either high (10 and 5 mm) or low concentration (2.5 and 1.5 mm). Photofrin concentration and incubation time were constant (2.5 μg/ml and 16 h). Under these conditions, we analysed cell viability, colony-forming efficiency, cycle profile, expression patterns of specific proteins and ubiquitination state, after individual or combined administration. RESULTS: Treatment with either PDT or aspirin, rapidly induced proteasome malfunction and accumulation of cells in G(2)M, but did not induce apoptosis. However, when aspirin was added to cells (even at low concentrations) after PDT, the proteasome block was sustained. Moreover, significant cytotoxic effects, including apoptosis, were observed along with cytostatic effects (G(2)M accumulation/decreased colony formation). CONCLUSIONS: Combination of PDT and low-toxicity drugs (such as aspirin) resulted in protracted inhibition of proteasome activity and induced apoptosis even in apoptosis-resistant cancer cells