Photoinduced antitumour effect of hypericin can be enhanced by fractionated dosing

Čavarga, Ivan; Brezáni, P; Fedoročko, Peter; Miškovský, Pavol; Bobrov, Nikita; Longauer, F; Rybárová, Silvia; Mirossay, Ladislav; Stubna, J

doi:10.1016/j.phymed.2004.02.011

Cited by 14 publications

(11 citation statements)

References 8 publications

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“…Arachidonic acid and its metabolites are closely linked to carcinogenesis. The antiproliferative potential of AA metabolism inhibitors has been broadly studied in vivo as well as in vitro (4,5,18). AA and eicosanoids serve as intermediates in growth factor signaling pathways, cell proliferation, cell death and inflammation processes.…”

Section: Discussionmentioning

confidence: 99%

“…Application in PDT of hypericin, a photosensitizer naturally occurring in Hypericum perforatum (St. John’s Wort), has demonstrated powerful photocytotoxic properties in vitro and in vivo alike (2–6). The molecular mechanisms involved generally in PDT, and particularly in hypericin‐based PDT, are not completely understood, although it has become clear that cell photosensitization initiates multiple signaling pathways, which ultimately leads to cell death (7–9).…”

Section: Introductionmentioning

confidence: 99%

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Modulation of Hypericin Photodynamic Therapy by Pretreatment with 12 Various Inhibitors of Arachidonic Acid Metabolism in Colon Adenocarcinoma HT‐29 Cells

Kleban

Mikes

Szilárdiová

et al. 2007

Photochem & Photobiology

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One proposal to increase the efficiency of photodynamic therapy (PDT) is to accompany photosensitization with other treatment modalities, including modulation of arachidonic acid (AA) metabolism. The aim of this study was to evaluate the effectiveness of a combined modality approach employing 48 and 24 h pretreatment with various inhibitors of lipoxygenase (LOX; nordihydroguaiaretic acid, esculetin, AA-861, MK-886 and baicalein), cyclooxygenase (COX; diclofenac, flurbiprofen, ibuprofen, indomethacin, SC-560 and rofecoxib) and cytochrome P450-monooxygenase (proadifen) pathways, followed by hypericin-mediated PDT. Cytokinetic parameters like MTT assay, adherent and floating cell numbers, viability and cell cycle distribution analysis were examined 24 h after hypericin activation. Pretreatment of human colon cancer cells HT-29 prior to PDT with 5-LOX inhibitor MK-886 as well as 5, 12-LOX and 12-LOX inhibitors (esculetin and baicalein, respectively) resulted in significant and dose-dependent effects on all parameters tested. Pretreatment with diclofenac, flurbiprofen, ibuprofen and indomethacin, the nonspecific COX inhibitors, promoted hypericin-mediated PDT, but these effects were probably COX-independent. In contrast, application of SC-560 and rofecoxib, specific inhibitors of COX-1 and COX-2, respectively, attenuated PDT. Inhibition of P450 monooxygenase with proadifen implied also the significance of this metabolic pathway in cell survival and cell resistance to hypericin photocytotoxicity. In conclusion, our results testify that application of diverse inhibitors of AA metabolism may have different consequences on cellular response to hypericin-mediated PDT and that some of them could be considered for potentiation of PDT.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modulation of Hypericin Photodynamic Therapy by Pretreatment with 12 Various Inhibitors of Arachidonic Acid Metabolism in Colon Adenocarcinoma HT‐29 Cells

Kleban

Mikes

Szilárdiová

et al. 2007

Photochem & Photobiology

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“…Hypericin, a natural product of H. perforatum (Saint John's wort), has been widely used as an effective treatment for depression 26, 27. In addition to antidepressive properties, hypericin has been shown to be able to induce apoptosis and radiosensitize tumor cells, and to have anti‐inflammatory and phototoxic skin effects 28, 29. Moreover, it showed great potential in photodynamic therapy 30.…”

Section: Discussionmentioning

confidence: 99%

Enhancing hypericin production of Hypericum perforatum cell suspension culture by ozone exposure

Yang

Dong

et al. 2011

Biotechnology Progress

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Accumulation of secondary metabolites is one of the common reactions of plants to ozone exposure in nature. To investigate the effect of ozone on the production of desired compounds of plant cell cultures, we assayed hypericin production of Hypericum perforatum suspension cell cultures treated with different doses of ozone at different culture phases. The results show that hypericin contents of the cells treated with 60 to 180 nL L(-1) ozone are significantly higher than those of the control, showing that ozone exposure may stimulate hypericin synthesis. Hypericin production of the cells treated with ozone at exponential phase is higher than that of lag and stationary phase, which suggests that exponential phase cell cultures are more responsive to ozone exposure than lag and stationary phase cells. The highest hypericin production is obtained by the cells exposed to 90 nL L(-1) ozone at late exponential phase for 3 h, being about fourfold of the control.

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“…Among others it possesses properties suitable for PDT (Čavarga et al, 2005;Chan et al, 2009) and PDD (Thong et al, 2009). Peculiar attributes of this photosensitizer are high efficiency in production of singlet oxygen (Redmond & Gamlin, 1999) and superoxide anions after irradiation with light wavelength around 600 nm and low or no toxicity in the dark (Jacobson et al, 2001;Miadoková et al, 2009).…”

Section: Hypericinmentioning

confidence: 99%

Breast Cancer and Current Therapeutic Approaches: From Radiation to Photodynamic Therapy

Ferenc¹,

Solár²,

Mikeš³

et al. 2011

Breast Cancer - Current and Alternative Therapeutic Modalities

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Photoinduced antitumour effect of hypericin can be enhanced by fractionated dosing

Cited by 14 publications

References 8 publications

Modulation of Hypericin Photodynamic Therapy by Pretreatment with 12 Various Inhibitors of Arachidonic Acid Metabolism in Colon Adenocarcinoma HT‐29 Cells

Modulation of Hypericin Photodynamic Therapy by Pretreatment with 12 Various Inhibitors of Arachidonic Acid Metabolism in Colon Adenocarcinoma HT‐29 Cells

Enhancing hypericin production of Hypericum perforatum cell suspension culture by ozone exposure

Breast Cancer and Current Therapeutic Approaches: From Radiation to Photodynamic Therapy

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