| 1. |
- Wallin, Åsa, 1976-, et al.
(författare)
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Anticancer effect of SN-38 on colon cancer cell lines with different metastatic potential
- 2008
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Ingår i: Oncology Reports. - : Spandidos Publications. - 1021-335X .- 1791-2431. ; 19:6, s. 1493-1498
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Tidskriftsartikel (refereegranskat)abstract
- SN-38 is an active metabolite of the topoisomerase I inhibitor irinotecan. The mechanism behind its antitumor effect in colorectal cancer is not fully understood. In this study, we examined the response of colon cancer cell lines with different metastatic potential to SN-38. The parental human colon cancer cell line KM12C and its two highly metastatic derivatives KM12SM and KM12L4a were cultivated in 5% CO2 at 37°C for 24 h and then exposed to SN-38 (2.5 µg/ml) at 37°C for 4, 24 and 48 h, respectively. The cell cycle was measured by flow cytometry, apoptotic activity was determined by flow cytometry and immunocytochemistry and the expression of topoisomerase I, Bax and survivin proteins were examined by Western blot. The exposure of the cells to SN-38 induced S-phase and G2 arrest (P<0.0001) and the KM12L4a cells had the highest response in a time-dependent manner (P<0.0001). The rates of apoptosis in the KM12SM (P=0.001) and KM12L4a cell lines (P=0.01) were increased time-dependently, though there was no such change in the KM12C cells. The expression of topoisomerase I protein was decreased in each cell line tested and the expression of Bax protein was increased, especially in KM12L4a. In conclusion, the effect of SN-38 on the colon cancer cell lines was mediated via conducting S-phase and G2 arrest and apoptosis. This effect was found in the cell lines with higher metastatic potentials, indicating that SN-38 can be used to treat advanced colon cancers.
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| 2. |
- Wallin, Åsa, 1976-, et al.
(författare)
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Gene Expression Profile of Colon Cancer Cell Lines Treated with SN-38
- 2010
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Ingår i: Chemotherapy. - : S. Karger AG. - 0009-3157 .- 1421-9794. ; 56:1, s. 17-25
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Colorectal cancer is the third most common form of cancer in the industrial countries. Due to advances regarding the treatments, primarily development of improved surgical methods and the ability to make the earlier diagnosis, the mortality has remained constant during the past decades even though the incidence in fact has increased. To improve chemotherapy and enable personalised treatment, the need of biomarkers is of great significance. In this study, we evaluated the gene expression profiles of the colon cancer cell lines treated with SN-38, the active metabolite of topoisomerase-1 inhibitor irinotecan which leads to cell cycle arrest and apoptosis. Material and Methods: The study included 3 colon cancer cell lines: KM12C, KM12SM and KM12l4a. The 3 cell lines were treated with SN-38, and samples were obtained after 24 and 48 hour treatments. The gene expression analyses were performed using oligonucleotide microarrays comprising of similar to 27,000 spots where the untreated controls were compared to the SN-38-treated samples. Results: Unsupervised clustering clearly distinguished the treated cell lines from the untreated. Supervised analysis identified 3,974 significant genes (p = 0.05) differentiating the treated samples from the untreated, majority of which were down-regulated after treatment. The top-ranked down-regulated genes in the treated cell lines included those related to receptor and kinase activity, signal transduction, apoptosis, RNA processing, protein metabolism and transport, cell cycle and transcription. A smaller number of genes were up-regulated in the cell lines after treatment and included genes involved in apoptosis, transcription, development and differentiation. Conclusions: These results demonstrate that the expression of the genes involved in cell proliferation and apoptosis as well as RNA, DNA and protein metabolism were affected by SN-38. The impact of certain genes on colorectal cancer development needs to be further evaluated; however, these results could serve as a basis for further studies in order to find targets for irinotecan treatment. Copyright (C) 2010 S. Karger AG, Basel
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| 3. |
- Wallin, Åsa, 1976-
(författare)
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Molecular Studies of Irradiation and SN-38 on Colorectal Cancer
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colorectal cancer (CRC) is one of most common cancer diseases worldwide. In Swedenapproximately 5,000 new cases of CRC are generated each year, which makes it the thirdmost common cancer disease among both men and women. The past decades ofimproved treatment strategies have considerably increased the five-year survival for CRCpatients. However more could be achieved in this area, in particular for metastatic CRC,which is the cause of most CRC-related deaths. Therefore it is important to study thebiological response to certain treatments induced in CRC to find valuable predictiveand/or prognostic factors to select patients for better suited treatments.The aim of this thesis was to gain insight into the molecular changes that occurfollowing irradiation or treatment with SN-38 in rectal cancer patients or colon cancercell lines by studying the RNA expression, protein expression, DNA cell cycledistribution and apoptotic response. The expression of phosphatase of regenerating liver(PRL) proteins was investigated in rectal cancers from 125 patients included in arandomized clinical trial of preoperative radiotherapy (RT). Increased expression of PRLswas seen at the invasive margin of primary and metastatic cancers compared with theinner area of the tumors. Moreover, strong PRL staining at the invasive margin correlatedto distant recurrence and worse survival of patients in the RT group but not in non-RTgroup (Paper I). Radiosensitivity was studied by treating KM12C, KM12SM andKM12L4a colon cancer cell lines with radiation. KM12C is of low metastatic naturecompared with the highly metastatic KM12SM and KM12L4a. Upregulation of ΔNp73and PRL-3 might contribute to the radioresistant phenotype in KM12C. In contrast,KM12L4a shows a high frequency of apoptosis and lack of upregulation of ΔNp73, PRL-3 and survivin, which might explain its radiosensitive phenotype (Paper II). KM12C,KM12SM and KM12L4a were treated with SN-38 which inhibits topoisomerase 1 (topo-1). The results show that SN-38 induces G2/S arrest and possess the capacity to triggerapoptosis in the three cell lines (Paper III). To further elucidate SN-38 effect on these celllines, the gene expression profile following SN-38 treatment was studied. Oligonucleotidearrays consisting of ~27,000 spots were hybridized with sample and reference cDNA.Both unsupervised and supervised hierarchical clustering analysis, and functional analysiswere performed. Supervised hierarchical clustering gives a strong signal of 1453discriminated genes, the vast majority being upregulated. Both upregulated anddownregulated genes point toward a favorable impact of SN-38 regarding the apoptoticpathways. For example RhoB and Bax are upregulated together with downregulation ofKras and survivin, which promotes apoptosis (Paper IV).In conclusion, PRLs may be valuable biomarkers for RT resistance, predicting apoor prognosis in rectal cancer patients. Targeting radio-resistance factors, such asΔNp73 and survivin may contribute to an increased sensitivity to RT. SN-38 affects cellproliferation and apoptosis.
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| 4. |
- Wallin, Åsa R., 1976-, et al.
(författare)
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Expression of PRL proteins at invasive margin of rectal cancers in relation to preoperative radiotherapy
- 2006
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 65:2, s. 452-458
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: PRL-3 (phosphatase of regenerating liver) is involved in metastasis of colorectal cancer; however, its therapeutic implication in cancer patients has not been studied. We investigated the relationships of PRL expression to radiotherapy (RT) in rectal cancer patients.Methods and Materials: Phosphatase of regenerating liver expression was immunohistochemically examined in distant (n = 36) and adjacent (n = 82) normal mucosa, primary tumor (n = 125), biopsy specimens (n = 96), and lymph node metastasis (n = 30) from rectal cancer patients participating in a clinical trial of preoperative RT.Results: Phosphatase of regenerating liver expression was increased from the distant to adjacent mucosa and to the primary tumor (p < 0.05). PRL was highly expressed at the invasive margin in 28% of the primary tumors and 26% of the metastases. In the RT group, strong PRL expression at the invasive margin was related to distant recurrence (p = 0.006) and poor survival (p = 0.01), but not in the non-RT group. The survival significance remained even after adjusting for Dukes’ stage and differentiation (p = 0.02). Additional multivariate analyses showed that the correlation with prognostic significance of PRL differed between the RT and non-RT groups (p = 0.01).Conclusion: Phosphatase of regenerating liver expression (rather than PRL-3 alone) at the invasive margin predicted resistance to RT and unfavorable survival in rectal cancer patients with preoperative RT.
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