TY - THES A1 - Hahlbrock, Theresa T1 - Das onkologische Supportivprodukt Avemar: Untersuchungen zum antiproliferativen und antimetabolischen Effekt an humanen gastrointestinalen Tumorzellen T1 - Studies on the antiproliferative and antimetabolic effect of the dietary supplement Avemar on human gastrointestinal tumor cells N2 - Unter dem Namen Avemar sind fermentierte Weizenkeimlinge als onkologisches Supportivprodukt erhältlich. Der hohe Anteil an 2,6-Dimethoxy-1,4-benzochinonen (DMBQ) in Avemar soll für das \(in\) \(vitro\) und \(in\) \(vivo\) belegte antikanzerogene Potential verantwortlich sein. DMBQ wirken über Semichinonradikale bzw. durch Ausbildung von reaktiven Sauerstoffspezies (ROS) und Induktion von oxidativem Stress zytotoxisch. Da Tumorzellen empfindlicher auf oxidativen Stress reagieren als gesunde Zellen, kann dies die selektive zytotoxische Wirkung von Avemar erklären. Die Beteiligung von DMBQ am antiproliferativen Effekt von Avemar und die Wirkung von Avemar auf den Stoffwechsel maligner Zellen sind derzeit nicht eindeutig geklärt. Die antiproliferativen Eigenschaften von Avemar und DMBQ als Reinsubstanz wurden miteinander verglichen. Hierzu wurden DMBQ in einer zu Avemar mit 0,04% Benzochinonen äquimolaren Konzentration von 24 μmol/L eingesetzt. Die Ergebnisse der Arbeit lassen den Schluss zu, dass der starke zytotoxische Effekt von Avemar bei BxPc-3 Zellen auf einen DMBQ-induzierten oxidativen Stress zurückzuführen ist. Im Vergleich zur unbehandelten Kontrolle wurde für BxPc-3 Zellen bei der Inkubation mit DMBQ eine 20-fache bzw. mit Avemar eine 40-fache Zunahme des ROS-Indikators 2',7'-Dichlorofluorescein gemessen. Im Westernblot ließ sich bei BxPc-3 Zellen das Enzym DT-Diaphorase, welches die Zellen vor Benzochinon-induziertem oxidativem Stress schützt, nicht nachweisen. In Zellen der anderen beiden Zelllinien konnte das Enzym nachgewiesen werden. Das mangelnde Schutzsystem gegenüber DMBQ-induziertem oxidativen Stress könnte demzufolge den DMBQ vermittelten zytotoxischen Effekt von Avemar in BxPc-3 Zellen erklären. Zusätzlich zum zytotoxischen Effekt wies Avemar zwei weitere antiproliferative Effekte auf: Zytostase bei 23132/87 Zellen und Wachstumsverzögerung bei HRT-18 Zellen. Beide antiproliferativen Effekte waren auf die Beeinflussung des Zellmetabolismus zurückzuführen. Avemar verringerte den zellulären Glukoseverbrauch von HRT-18 Zellen um 69% und von 23132/87 Zellen um 99%. In 23132/87 Zellen korrelierte der verringerte Glukoseverbrauch mit einer Abnahme von ATP um 70% und einem Zellzyklusarrest in der G\(_2\)/M Phase. Der durch die Inkubation von HRT-18 Zellen mit Avemar ausgelöste verringerte Glukoseverbrauch beeinflusste hingegen weder den ATP-Gehalt noch den Zellzyklus, induzierte aber Autophagie. Dies ließ sich zeigen durch morphologische Veränderungen wie die Bildung von intrazellulären Vakuolen und durch den Nachweis des Autophagiemarkers LC3-II. Die Wertigkeit dieses Phänomens für die zytotoxischen Eigenschaften von Avemar ist in weiteren Untersuchungen zu klären. Die antiproliferativen Eigenschaften von Avemar führen zu Veränderungen im Zellmetabolismus von gastrointestinalen Tumorzellen. Ausschlaggebend dafür, welcher der drei antiproliferativen Effekte von Avemar (zytotoxisch, zytostatisch oder wachstumsverzögernd) dominiert, sind vermutlich zelleigene Schutzsysteme und metabolische Charakteristika der Zellen. Avemar weist ein breites Spektrum antiproliferativer Effekte auf, deren Einfluss auf Zellfunktion und Zellstoffwechsel im Detail noch weiter untersucht werden sollte. N2 - The commercial product Avemar is an oncologic supportive drug that consists of fermented wheat germ extracts. The high content of 2,6-dimethoxy-1,4-benzoquinone (DMBQ) in Avemar is thought to be responsible for the anticancer effects, which were observed both \(in\) \(vitro\) and \(in\) \(vivo\) experiments. The cytotoxic effect of DMBQ is caused by semiquinone radicals which induce oxidative stress in cells. Because tumor cells are more sensitive to oxidative stress than benign cells, the presence of semiquinone radicals might explain the selective cytotoxic effect of Avemar. However, the role of DMBQ in the antiproliferative mechanism of Avemar and the effect of Avemar on the metabolism of malignant cells have not yet been clarified. In this work, the antiproliferative features of Avemar were compared to those of DMBQ as a pure substance. DMBQ was investigated in a concentration of 24 μmol/L, which is equimolar to Avemar with a concentration of 0.04% of DMBQ. Both Avemar and DMBQ exhibited an increase of reactive oxygen species in BxPc-3 cells, which resulted in a cytotoxic effect within 24 hours after starting treatment. Compared to untreated cells, intracellular DCF fluorescence as a measure of reactive oxygen species increased by 20 times for DMBQ and 40 times for Avemar in BxPc-3 cells. Western Blot analysis revealed that the enzyme DT-diaphorase, which protects cells against benzoquinone-induced oxidative stress, was not present in BxPc-3 cells. In contrast, the enzyme could be detected in cells of the other two cell lines. The lack of DT-diaphorase in BxPc-3 cells indicates insufficient protection against DMBQ-induced oxidative stress which could consequently result in a DMBQ-mediated cytotoxic effect when exposed to Avemar. Besides the cytotoxic effect, Avemar showed two additional antiproliferative features: cytostasis in 23132/87 cells and growth delay in HRT-18 cells. Both antiproliferative effects of Avemar were caused by the influence of the substance on the cell metabolism. Avemar impaired the cellular consumption of glucose by 69% in HRT-18 cells and by 99% in 23132/87 cells. The impaired consumption of glucose in 23132/87 cells correlated with a decrease of ATP by 70% and an arrest in the G\(_2\)/M phase during the cell cycle of 23132/87. In contrast, when treated with Avemar, the impaired consumption of glucose in HRT-18 cells did not affect the ATP concentration and did not alter the cell cycle. Instead, Avemar leads to autophagy, as indicated by the formation of intracellular vacuoles. The presence of autophagy in HRT-18 cells was confirmed by the detection of the autophagy marker LC3-II. The relevance of this phenomenon for the cytotoxic properties of Avemar is to be clarified in further studies. Three different mechanisms of action of Avemar were identified: cytotoxic, cytostasis, and growth delay. The relevant effect on each cell type is presumably determined by the available protection mechanism and metabolic character of the cells. Avemar shows a broad spectrum of antiproliferative features whose exact influence on the functions and metabolism of the cell remains to be investigated in more detail in future studies. KW - Oxidativer Stress KW - Chinonderivate KW - Alternative Medizin KW - Gastrointestinaler Tumor KW - Weizenkeim KW - 2,6-Dimethoxybenzochinon KW - Avemar KW - Fermentierte Weizenkeimlinge KW - Autophagie KW - 2,6-Dimethoxybenzoquinone KW - fermented wheat germ KW - autophagy Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-145787 ER - TY - JOUR A1 - Otto, Christoph A1 - Hahlbrock, Theresa A1 - Eich, Kilian A1 - Karaaslan, Ferdi A1 - Jürgens, Constantin A1 - Germer, Christoph-Thomas A1 - Wiegering, Armin A1 - Kämmerer, Ulrike T1 - Antiproliferative and antimetabolic effects behind the anticancer property of fermented wheat germ extract JF - BMC Complementary and Alternative Medicine N2 - Background Fermented wheat germ extract (FWGE) sold under the trade name Avemar exhibits anticancer activity in vitro and in vivo. Its mechanisms of action are divided into antiproliferative and antimetabolic effects. Its influcence on cancer cell metabolism needs further investigation. One objective of this study, therefore, was to further elucidate the antimetabolic action of FWGE. The anticancer compound 2,6-dimethoxy-1,4-benzoquinone (DMBQ) is the major bioactive compound in FWGE and is probably responsible for its anticancer activity. The second objective of this study was to compare the antiproliferative properties in vitro of FWGE and the DMBQ compound. Methods The IC\(_{50}\) values of FWGE were determined for nine human cancer cell lines after 24 h of culture. The DMBQ compound was used at a concentration of 24 μmol/l, which is equal to the molar concentration of DMBQ in FWGE. Cell viability, cell cycle, cellular redox state, glucose consumption, lactic acid production, cellular ATP levels, and the NADH/NAD\(^+\) ratio were measured. Results The mean IC\(_{50}\) value of FWGE for the nine human cancer cell lines tested was 10 mg/ml. Both FWGE (10 mg/ml) and the DMBQ compound (24 μmol/l) induced massive cell damage within 24 h after starting treatment, with changes in the cellular redox state secondary to formation of intracellular reactive oxygen species. Unlike the DMBQ compound, which was only cytotoxic, FWGE exhibited cytostatic and growth delay effects in addition to cytotoxicity. Both cytostatic and growth delay effects were linked to impaired glucose utilization which influenced the cell cycle, cellular ATP levels, and the NADH/NAD\(^+\) ratio. The growth delay effect in response to FWGE treatment led to induction of autophagy. Conclusions FWGE and the DMBQ compound both induced oxidative stress-promoted cytotoxicity. In addition, FWGE exhibited cytostatic and growth delay effects associated with impaired glucose utilization which led to autophagy, a possible previously unknown mechanism behind the influence of FWGE on cancer cell metabolism. KW - cytostatic KW - FWGE KW - benzoquinone KW - cancer cells KW - reactive oxygen species KW - autophagy KW - cytotoxicity Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146013 VL - 16 IS - 160 ER -