| 1. |
- Funa, Nina S, et al.
(författare)
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Dysfunctional microvasculature as a consequence of shb gene inactivation causes impaired tumor growth
- 2009
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 69:5, s. 2141-2148
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Tidskriftsartikel (refereegranskat)abstract
- Shb (Src homology 2 protein B) is an adapter protein downstream of the vascular endothelial growth factor receptor receptor-2 (VEGFR-2). Previous experiments have suggested a role for Shb in endothelial cell function. Recently, the Shb gene was inactivated and Shb null mice were obtained on a mixed genetic background, but not on C57Bl6 mice. The present study was performed to address endothelial function in the Shb knockout mouse and its relevance for tumor angiogenesis. Tumor growth was retarded in Shb mutant mice, and this correlated with decreased angiogenesis both in tumors and in Matrigel plugs. Shb null mice display an abnormal endothelial ultrastructure in liver sinusoids and heart capillaries with cytoplasmic extensions projecting toward the lumen. Shb null heart VE-cadherin staining was less distinct than that of control heart, exhibiting in the former case a wavy and punctuate pattern. Experiments on isolated endothelial cells suggest that these changes could partly reflect cytoskeletal abnormalities. Vascular permeability was increased in Shb null mice in heart, kidney, and skin, whereas VEGF-stimulated vascular permeability was reduced in Shb null mice. It is concluded that Shb plays an important role in maintaining a functional vasculature in adult mice, and that interference with Shb signaling may provide novel means to regulate tumor angiogenesis.
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| 2. |
- Kriz, Vitezslav, et al.
(författare)
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Shb null allele is inherited with a transmission ratio distortion and causes reduced viability in utero
- 2007
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Ingår i: Developmental Dynamics. - : Wiley. - 1058-8388 .- 1097-0177. ; 236:9, s. 2485-2492
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Tidskriftsartikel (refereegranskat)abstract
- SHB is an Src homology 2 domain-containing adapter protein that has been found to be involved in numerous cellular responses. We have generated an Shb knockout mouse. No Shb-/- pups or embryos were obtained on the C57Bl6 background, indicating an early defect as a consequence of Shb- gene inactivation on this genetic background. Breeding heterozygotes for Shb gene inactivation (Shb+/-) on a mixed genetic background (FVB/C57Bl6/129Sv) reveals a distorted transmission ratio of the null allele with reduced numbers of Shb+/+ and Shb-/- animals, but increased number of Shb+/- animals. The Shb- allele is associated with various forms of malformations, explaining the relative reduction in the number of Shb-/- offspring. Shb-/- animals that were born were viable, fertile, and showed no obvious defects. However, Shb+/- female mice ovulated preferentially Shb- oocytes explaining the reduced frequency of Shb+/+ mice. Our study suggests a role of SHB during reproduction and development.
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| 3. |
- Kriz, Vitezslav, et al.
(författare)
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The SHB adapter protein is required for normal maturation of mesoderm during in vitro differentiation of embryonic stem cells
- 2006
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 281:45, s. 34484-34491
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Tidskriftsartikel (refereegranskat)abstract
- Definitive mesoderm arises from a bipotent mesendodermal population, and to study processes controlling its development at this stage, embryonic stem (ES) cells can be employed. SHB ((S) under bar rc (h) under bar omology 2 protein in beta-cells) is an adapter protein previously found to be involved in ES cell differentiation to mesoderm. To further study the role of SHB in this context, we have established ES cell lines deficient for one (SHB+/-) or both SHB alleles (SHB-/-). Differentiating embryoid bodies (EBs) derived from these ES cell lines were used for gene expression analysis. Alternatively, EBs were stained for the blood vessel marker CD31. For hematopoietic differentiation, EBs were differentiated in methylcellulose. SHB-/- EBs exhibited delayed down-regulation of the early mesodermal marker Brachyury. Later mesodermal markers relatively specific for the hematopoietic, vascular, and cardiac lineages were expressed at lower levels on day 6 or 8 of differentiation in EBs lacking SHB. The expression of vascular endothelial growth factor receptor-2 and fibroblast growth factor receptor-1 was also reduced in SHB-/- EBs. SHB-/- EBs demonstrated impaired blood vessel formation after vascular endothelial growth factor stimulation. In addition, the SHB-/- ES cells formed fewer blood cell colonies than SHB+/+ ES cells. It is concluded that SHB is required for appropriate hematopoietic and vascular differentiation and that delayed down-regulation of Brachyury expression may play a role in this context.
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| 4. |
- Schultz, Iman J, et al.
(författare)
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Gene expression analysis for the prediction of recurrence in patients with primary Ta urothelial cell carcinoma
- 2007
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Ingår i: European Urology. - : Elsevier BV. - 0302-2838 .- 1873-7560. ; 51:2, s. 416-423
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The individual recurrence-free period after primary surgery of patients with Ta urothelial cell carcinoma (UCC) cannot be predicted accurately. This study aims at discriminating between patients with primary Ta UCC and long or short recurrence-free periods. Methods We investigated mRNA expression of 23 genes in 44 primary Ta tumours (23 and 21 tumours were from patients with long [≥4 yr] or short [≤2 yr] recurrence-free periods, respectively), using real-time quantitative polymerase chain reaction. The genes were selected from previously published studies and showed a relationship with tumour recurrence in patients with UCC. Results Differential mRNA expression between the two patient groups indicated statistical significance only for the gene survivin (p = 0.0011). Its recurrence predictive value could not be increased by a combination with any of the other genes. Comparison of the receiver operating characteristic curves for survivin expression between patients with long or short recurrence-free intervals revealed an area under the curve of 0.79 (95%CI, 0.65–0.92). Using the median expression (0.84) as cut-off level, survivin identified 71.4% (95%CI, 47.8–88.7) and 69.6% (95%CI, 47.1–86.8) of the patients with long or short recurrence-free periods, respectively. Conclusions Our study identifies survivin as the most promising candidate to distinguish between patients with primary Ta UCC and long or short recurrence-free intervals. Therefore, survivin mRNA expression analysis might help the urologist to individualise patient treatment and prevent unnecessary cystoscopies in a subgroup of these patients.
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| 5. |
- Schultz, Iman J., et al.
(författare)
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Prediction of recurrence in Ta urothelial cell carcinoma by real-time quantitative PCR analysis : a microarray validation study
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 119:8, s. 1915-1919
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Tidskriftsartikel (refereegranskat)abstract
- Accurate prediction of tumor recurrence in patients with superficial urothelial cell carcinoma (UCC) might result in a significant reduction of invasive follow-up cystoscopies. A recent study identified a panel of 26 genes from a large cDNA microarray analysis of bladder tumors that discriminated between early- and late-recurring patients with superficial Ta tumors (Dyrskjot et al., Nat Genet 2003;33:90-6). We aimed to validate this panel of genes in 44 primary Ta UCCs (23 and 21 tumors from patients with short or prolonged recurrence-free periods, respectively), by real-time quantitative PCR. Statistical analysis showed marginal significant different mRNA expression levels between the 2 patient groups. To evaluate a supplementary effect of genes for the identification of patients with short or prolonged recurrence-free intervals, forward logistic regression analysis was applied. This revealed that a combination of the expression profiles of the genes HNRPK, LTB4DH and ANP32B resulted in the best performance, although the combination only marginally increased the predictive value of HNRPK alone. Comparing the receiver-operating-characteristic curves for HNRPK expression among patients with short or prolonged recurrence-free periods, revealed an area under the curve of 0.696 (95% CI, 0.537-0.855). Using the median HNRPK expression level as cut-off, a sensitivity of 69.6% and a specificity of 71.4% were obtained for the identification of patients with short or prolonged recurrence-free periods, respectively. In conclusion, we were not able to confirm the microarray gene expression pattern of the 26 genes shown by Dyrskjot et al. The discovery of accurate recurrence predictive markers, therefore, remains a challenge.
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