High-performance liquid chromatographic analysis of “available” hemin in hematin solutions

Bauer, John F.; Fornnarino, Joseph R.

doi:10.1016/s0021-9673(00)96276-9

Cited by 21 publications

(8 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, most of the ALA-generated PpIX under the incubation conditions used was restricted to mitochondria. The pre-irradiation intracellular content of PpIX was found to be 0.44 ± 0.05 nmol/mg of protein (mean ± SD; n = 3), as determined spectrofluorimetrically (λ ex 405 nm; λ em 630 nm) using a PpIX standard (27). This value was reproducible within 10% for routine cell incubations with ALA as described, and SPNO had no significant effect on it.…”

Section: Resultsmentioning

confidence: 99%

Signaling events in apoptotic photokilling of 5-aminolevulinic acid-treated tumor cells: Inhibitory effects of nitric oxide

Bhowmick

Girotti

2009

Free Radical Biology and Medicine

View full text Add to dashboard Cite

Antitumor photodynamic therapy (PDT) employs a photosensitizing agent, molecular oxygen, and visible light to produce reactive oxygen species that can destroy tumor and tumor vasculature cells. NO produced by these cells could be pro-carcinogenic by inhibiting apoptosis and promoting angiogenesis and tumor growth. We recently showed that NO from a chemical donor or activated macrophages makes COH-BR1 breast tumor cells more resistant to photokilling sensitized by 5-aminolevulinic acid (ALA)-generated protoporphyrin IX (PpIX). Signaling events associated with this hyperresistance have now been examined. ALA-treated COH-BR1 cells containing mitochondria-localized PpIX died mainly by apoptosis after being irradiated. Underlying redox signaling associated with MAP kinase (ERK1/2, p38, JUN) phosphorylation-activation and heme oxygenase-1 (HO-1) upregulation was studied using immunoprecipitation and Western blot methodology. ALA/light treatment resulted in activation of pro-apoptotic JNK and p38α, and deactivation of pro-survival p38β and ERK1/2. Involvement of both JNK and p38 in apoptosis was established by using a specific inhibitor for each. Spermine NONOate-derived NO, introduced immediately before irradiation, provided substantial protection against apoptosis. This was accompanied by greater HO-1 induction and strong inhibition of each MAP kinase effect seen in the absence of NO. Downstream of JNK and p38α activation, a marked upregulation/activation of proapoptotic Bax and Bid was observed along with down-regulation of anti-apoptotic Bcl-xL, each response being reversed by NO. These findings provide new insights into signaling activity associated with the intrinsic apoptotic pathway in ALA-PDT and how this activity can be modulated by NO.

show abstract

Section: Resultsmentioning

confidence: 99%

Signaling events in apoptotic photokilling of 5-aminolevulinic acid-treated tumor cells: Inhibitory effects of nitric oxide

Bhowmick

Girotti

2009

Free Radical Biology and Medicine

View full text Add to dashboard Cite

show abstract

“…Most of the ALA-derived PpIX at this point had diffused from mitochondria (where it is synthesized) to peripheral sites, including plasma membrane (41). Total [PpIX] in cells prepared according to this procedure, previously referred to as ''protocol-2'' (41), was 1.1 6 0.2 nmol/mg protein, as determined by HPLC with A 405 detection (42). Following treatment, the cells were washed and overlaid with RPMI medium either lacking or containing PAPA/NO or SPER/NO (typically 0.4 mM) and irradiated immediately.…”

Section: Methodsmentioning

confidence: 98%

Chain-breaking Antioxidant and Cytoprotective Action of Nitric Oxide on Photodynamically Stressed Tumor Cells¶

Niziolek

Korytowski

Girotti

2003

Photochem Photobiol

View full text Add to dashboard Cite

Nitric oxide (.NO) has a multitude of physiological roles, including the ability to protect cells against oxidant-induced killing, e.g. by inhibiting caspase-mediated apoptosis or by intercepting damaging free radicals derived from membrane lipids. The purpose of this study was to test the hypothesis that low flux .NO acting in the latter fashion can enhance tumor-cell resistance to photodynamic killing, specifically that sensitized by 5-aminolevulinic acid (ALA)-derived protoporphyrin IX (PpIX). Preliminary model experiments with iron-ascorbate-treated, PpIX-sensitized liposomes showed that spermine NONOate (SPER/NO)-derived .NO had no effect on photoinduced accumulation of primary singlet oxygen adducts, e.g. the cholesterol hydroperoxide 5 alpha-OOH, but dose-dependently inhibited the buildup of free radical-generated oxidation products arising from one-electron turnover of primary peroxides. In subsequent studies, breast tumor COH-BR1 cells in serum-free medium were treated with 1 mM ALA for 15 min and then without ALA for 3.75 h, allowing biogenerated PpIX to diffuse to extramitochondrial sites, including plasma membrane. Cells were irradiated in the absence or presence of SPER/NO and compared for peroxidative damage and Hoechst-assessed viability after 5 h in the dark. Iron-stimulated necrotic photo-killing and accumulation of chain lipid peroxidation products were observed, and this was inhibited strongly by SPER/NO, but not by decomposed SPER/NO, confirming that .NO was the active agent. When introduced after irradiation, .NO became progressively less inhibitory, consistent with ongoing but waning free-radical activity. These findings provide new insights into the possible role of .NO in tumor resistance to ALA-photodynamic therapy and other photo-dynamic treatments.

show abstract

“…Observations on drug metabolism in rodents are not necessarily applicable to primates; in the study with monkeys haem administration (4 mg kg-' intravenously for 4 days) did not increase the activity ofhaem oxygenase. This may indicate that the amount ofactive haem given to the monkeys was possibly quite small due to the extreme instability of conventional haematin solutions at room temperature (Mendenhall, 1984;Bauer & Fornnarino, 1984). In many studies the preparation and storage of haematin solutions are not stated or evaluated in detail.…”

Section: Discussionmentioning

confidence: 99%

Effects of repeated intravenous administration of haem arginate upon hepatic metabolism of foreign compounds in rats and dogs

Tokola

1987

British J Pharmacology

View full text Add to dashboard Cite

1 Haem arginate is a new haem compound, recently introduced for the treatment of acute hepatic porphyrias. Porphyrias are characterized biochemically by decreased formation ofhaem due to defects in certain enzyme activities involved in the haem biosynthesis. 2 Haem is essential for cell respiration and oxidative biotransformation. Hepatic drug metabolism, haem biosynthesis and catabolism were investigated after repeated intravenous administration of haem arginate in connection with toxicity studies. 3 The daily doses ofhaem for rats were 4, 12 and 40mg kg-and for dogs 3 and 9mg kg-' for 30 days and for 28 days, respectively. 4 Hepatic microsomes were used in the assay of the following drug metabolizing enzymes: cytochrome P-450 and b5, aminopyrine N-demethylase, ethoxyresorufin O-deethylase and UDPglucuronyl transferase. The assay of NADPH-cytochrome C-reductase and the enzymes reflecting synthesis and metabolism ofhaem in the liver (6-aminolaevulinic acid synthase, 6-aminolaevulinic acid dehydratase, uroporphyrinogen I-synthase, uroporphyrinogen decarboxylase, haem synthase, haem oxygenase and biliverdin reductase) were performed from 20,000g supernatants. 5The lowest dose administered to rats and dogs did not cause any significant changes compared to controls in the parameters measured. 6 The highest doses significantly increased the activities of haem oxygenase and uroporphyrinogen Isynthase but decreased concentrations or activities of other enzymes, e.g. cytochrome P-450 and ethoxyresorufin O-deethylase. 7 The results show that it is important to avoid overdosage of haem when restoration of mixed function oxygenase activity is needed.

show abstract

High-performance liquid chromatographic analysis of “available” hemin in hematin solutions

Cited by 21 publications

References 4 publications

Signaling events in apoptotic photokilling of 5-aminolevulinic acid-treated tumor cells: Inhibitory effects of nitric oxide

Signaling events in apoptotic photokilling of 5-aminolevulinic acid-treated tumor cells: Inhibitory effects of nitric oxide

Chain-breaking Antioxidant and Cytoprotective Action of Nitric Oxide on Photodynamically Stressed Tumor Cells¶

Effects of repeated intravenous administration of haem arginate upon hepatic metabolism of foreign compounds in rats and dogs

Contact Info

Product

Resources

About