| 1. |
- Fulda, S., et al.
(författare)
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Betulinic acid triggers CD95 (APO-1/Fas)- and p53-independent apoptosis via activation of caspases in neuroectodermal tumors
- 1997
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 57:21, s. 4956-4964
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Tidskriftsartikel (refereegranskat)abstract
- Betulinic acid CBA), a melanoma-specific cytotoxic agent, induced apoptosis in neuroectodermal tumors, such as neuroblastoma, medulloblastoma, and Ewing's sarcoma, representing the most common solid tumors of childhood. BA triggered an apoptosis pathway different from the one previously identified for standard chemotherapeutic drugs. BA-induced apoptosis was independent of CD95-ligand/receptor interaction and accumulation of wild-type p53 protein, but it critically depended on activation of caspases (interleukin 1 beta-converting enzyme/Ced-3-like proteases), FLICE/MACH (caspase-8), considered to be an upstream protease in the caspase cascade, and the downstream caspase CPP32/YAMA/Apopain (caspase-3) were activated, resulting in cleavage of the prototype substrate of caspases PARP. The broad-spectrum peptide inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, which blocked cleavage of FLICE and PARP, also completely abrogated BA-triggered apoptosis. Cleavage of caspases was preceded by disturbance of mitochondrial membrane potential and by generation of reactive oxygen species. Overexpression of Bcl-2 and Bcl-x(L) conferred resistance to BA at the level of mitochondrial dysfunction, protease activation, and nuclear fragmentation. This suggested that mitochondrial alterations were involved in BA-induced activation of caspases. Furthermore, pax and Bcl-x(s), two death-promoting proteins of the Bcl-2 family, were up-regulated following BA treatment. Most importantly, neuroblastoma cells resistant to CD95- and doxorubicin-mediated apoptosis were sensitive to treatment with BA, suggesting that BA may bypass some forms of drug resistance. Because BA exhibited significant antitumor activity on patients' derived neuroblastoma cells ex vivo, BA may be a promising new agent for the treatment of neuroectodermal tumors in vivo.
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| 2. |
- Nilsson, Henrik, et al.
(författare)
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Laser-induced fluorescence studies of the biodistribution of carotenoporphyrins in mice
- 1997
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 76:3, s. 355-364
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Tidskriftsartikel (refereegranskat)abstract
- The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated.
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| 3. |
- Nordlund, Lars Anders, et al.
(författare)
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Cancer incidence in female smokers : a 26-year follow-up
- 1997
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Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 73:5, s. 625-628
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Tidskriftsartikel (refereegranskat)abstract
- A random sample of 26,000 Swedish women who were asked about their smoking habits in the early 1960s have now been followed for 26 years with respect to cancer incidence. Most findings regarding tobacco smoking and cancer from studies of men were confirmed also among the women. Elevated relative risk for current smokers compared with women who never smoked regularly were seen for cancers of the lung, upper aerodigestive sites, pancreas, bladder, cervix and all cancers combined, as well as a notably high relative risk for cancers of organs of the urinary tract other than kidney and bladder. Relative risk increased with dose, measured as grams of tobacco smoked per day, for cancers of the upper aerodigestive sites, lung, cervix, bladder, organs of the urinary tract other than kidney and bladder and all cancers combined. For cancers of the lung, bladder and cervix, there was an inverse relationship with age when starting to smoke tobacco. The reported inverse relationship between smoking and endometrial cancer could not be corroborated, nor was there any significant relationship between smoking and colorectal or breast cancer.
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