[Viblastin poveča protitumorsko učinkovitost bleomicina]

In our previous vinblastine (VELBE) was shown to increase the plasma membrane fluidity. This effect of VELBE might be expolited for better transport of drugs through the plasma membrane. Bleomycin (BLM) is a highly cytotoxic drug when present inside the cells but has a hampered transport through the plasma membrane. The aim of the present study was to determine whether pretreatment with VELBE can increase the effect of BLM on intraperitoneal SA-1 tumors in mice. BLM and VELBE were used as single agents or in various combinations, i.e. VELBE and BLM injected simultanously, BLM injected 24 h before VELBE or VELBE injected 24 h before BLM. Mice survival was the end-point used for determining the effect of this combined treatments. VELBE and BLM as a single treatment significantly prolonged median survival time of study animals compared to controls. Furthermore, when VELBE and BLM were combined, all threetested combinations were more effective than VELBE or BLM as single treatments. The effect on animal survival was equal when VELBE was given 24 h after or simultanously with BLM. The longest survival, however was obtained when VELBE was injected 24 h before BLM. From these results we can conclude that the underlying mechanisms for more than additive effect of VELBE and BLM when VELBE was given 24 h before BLM could be attributed to an increased membrane fluidity, possibly in combination with a cell kinetic effect.V naši predhodni študiji smo ugotovili, da vinblastin poveča fluidnost plazemske membrane. S tem lahko povečamo vnos bleomcina, ki slabo prehaja preko plazemske membrane, a je zelo citotoksičen, če je prisoten v celici. Namen naše raziskave je bil na mišjih intraperitonealnih SA-1 tumorjih določiti, ali njiciranje vinblastina pred bleomicinom poveča učinkovitost bleomicina. Mišim smo injicirali samo vinblastin, samo bleomicin, vinblastin in bleomicin skupaj v različnih kombinacijah: vinblastin in bleomicin injicirana sočasno, bleomicin injiciran 24 h pred vinblastinom in vinblastin injiciran 24 h pred bleomicinom. Učinkovitost terapije smo ugotavljali s preživetjem živali. Zdravljenje z vinblastinom in bleomicinom je statistično značilno podaljšalo preživetje živali glede na kontrolno skupino. Vse tri kombinacije vinblastina in bleomicina so bile bolj učinkovite kot zdralvjenje samo z enim kemoterapevtikom. Učinek terapije je bil enak, če smo sočasno injicirali vinblastin in bleomicin, ali če smo injicirali bleomicin 24 h pred vinblastinom. Najdaljše preživetje živali pa smo dobili, če smo injicirali vinblastin 24 h pred bleomicinom. Glede na naše rezultate lahko predpostavljamo, da sta za dobljeni učinek terapije odgovorna dva mehanizma delovanja vinblastina: povečanje fluidnosti membrane in vejretno celično kinetični efekt

Protitumorsko delovanje bleomicina na SA-1 tumorjih po predhodni terapiji z vinblastinom

In our previous study, vinblastine (VLB) was shown to increase the plasma membrane fluidity. This effect of VLB might be exploited for better transport of drugs through the plasma membrane. The aim of the present study was to determine whether pretreatment with VLB can increase the cytotoxic effect of BLM on intraperitoneal SA-1 tumors in mice. Materials and methods. BLM and VLBwere used as single agents or in various combinations, i.e. BLM injected 24h before VLB or vice-versa, VLB injected 24 h before BLM. Cell and animal survival together with DNA histograms were the end-points used to determine the effect of these combined treatments. Results. Both drugs, either as singletreatment or in different combined therapy schedules reduced significantly the number of cells in peritoneal lavage, compared to control, saline treated animals. The combination of VLB, followed by BLM after 24 h reduced significantly the number of cells in peritoneal lavage, compared to the treatment in which BLM was followed by VLB or to the treatment with singledrugs alone. Median survival time of mice treated with VLB alone, BLM alone and combination of both drugs was significantly prolonged compared to the control untreated mice. When VLB and BLM were combined, both treatment combinations were more effective than monochemotherapies with VLB or BLM. The best results were obtained when VLB was followed by BLM after 24 h. The DNA histogram of cells treated with VLB showed a decreased number of cells in S phase and an increased number of cells with DNA values greater than in G2M compartment compared to the control untreated cells. BLM in the dosage used inthese experiments did not affect the progression of cells through cell cycle. Both combinations of VLB and BLM produced similar cell kinetic effect as VLB alone. Conclusion. (Abstract truncated at 2000 characters.)Izhodišča. V naši predhodni študiji smo ugotovili, da vinblastin (VLB) poveča fluidnost plazmaleme, kar bi lahko izkoristili za povečan transport zdravil preko plazmaleme. Namen naše raziskave je bil na mišjih intraperitonealnih tumorjih določiti, ali se poveča učinkovitost bleomicina (BLM) po predhodni terapiji z VLB. Materiali in metode. Mišim smo injicirali samo VLB ali samo BLM ter obe zdravili v dveh kombinacijah: VLB injiciran 24 h pred BLM in BLM injiciran 24 h pred VLB. Učinkovitost terapije smo ugotavljali s preživetjem živali, štetjem celic, izoliranih iz peritonealne votline miši, ter DNA histogrami. Rezultati. Obe zdravili, bodisi kot mono kemoterapiji ali v kombinaciji, sta povzročili značilno zmanjšanje števila celic v peritonealni votlini v primerjavi s kontrolno skupino. Ko smo injicirali VLB 24 h pred BLM je bilo število celic v izolatu peritonealne votline značilno zmanjšano v primerjavi z monokemoterapijama in s skupino, ko smo BLM injicirali 24 h pred VLB. Preživetje živali, zdravljenih samo z VLB ali samo z BLM ter obema kombinacijama zdravil, je bilo značilno podaljšano glede na kontrolno nezdravljeno skupino miši. Obe kombinaciji VLB in BLM sta bili tudi bolj učinkoviti kot monokemoterapiji. Najboljši rezultat pa smo dobili pri skupini,kjer smo injicirali VLB 24 h pred BLM. V primerjavi z DNA histogramom kontrolnih celic smo v DNA histogramu celic, ki so bile izpostavljene delovanju VLB, izmerili zmanjšano število celic v S fazi in povečano število celic z večjo količino DNA, kot jo imajo celice v G2M fazi celičnega ciklusa. Doza BLM, ki smo jo uporabili v naših poskusih, ni imela učinka na progresijo celic skozi celični ciklus. Obe kombinaciji VLB in BLM sta imeli podoben celično kinetični učinek kot sam VLB. Zaključek. Glede na naše rezultate lahkozaključimo, da je mehanizem odgovoren za povečan učinek terapije, v kateri smo dali VLB 24 h pred BLM, predvsem povečana fluidnost celične membrane in verjetno tudi celično kinetični učinek V

EGF-Induced EMT and Invasiveness in Serous Borderline Ovarian Tumor Cells: A Possible Step in the Transition to Low-Grade Serous Carcinoma Cells?

In high-grade ovarian cancer cultures, it has been shown that epidermal growth factor (EGF) induces cell invasion by activating an epithelial-mesenchymal transition (EMT). However, the effect of EGF on serous borderline ovarian tumors (SBOT) and low-grade serous carcinomas (LGC) cell invasion remains unknown. Here, we show that EGF receptor (EGFR) was expressed, that EGF treatment increased cell migration and invasion in two cultured SBOT cell lines, SBOT3.1 and SV40 large T antigen-infected SBOT cells (SBOT4-LT), and in two cultured LGC cell lines, MPSC1 and SV40 LT/ST-immortalized LGC cells (ILGC). However, EGF induced down-regulation of E-cadherin and concurrent up-regulation of N-cadherin in SBOT cells but not in LGC cells. In SBOT cells, the expression of the transcriptional repressors of E-cadherin, Snail, Slug and ZEB1 were increased by EGF treatment. Treatment with EGF led to the activation of the downstream ERK1/2 and PI3K/Akt. The MEK1 inhibitor PD98059 diminished the EGF-induced cadherin switch and the up-regulation of Snail, Slug and ZEB1 and the EGF-mediated increase in SBOT cell migration and invasion. The PI3K inhibitor LY294002 had similar effects, but it could not block the EGF-induced up-regulation of N-cadherin and ZEB1. This study demonstrates that EGF induces SBOT cell migration and invasion by activating EMT, which involves the activation of the ERK1/2 and PI3K/Akt pathways and, subsequently, Snail, Slug and ZEB1 expression. Moreover, our results suggest that there are EMT-independent mechanisms that mediate the EGF-induced LGC cell migration and invasion