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| 9. |
- Halin, Sofia, 1977-, et al.
(author)
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Extratumoral macrophages promote tumor and vascular growth in an orthotopic rat prostate tumor model.
- 2009
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In: Neoplasia. - 1522-8002 .- 1476-5586. ; 11:2, s. 177-186
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Journal article (peer-reviewed)abstract
- Tumor-associated macrophages are involved in angiogenesis and tumor progression, but their role and specific site of action in prostate cancer remain unknown. To explore this, Dunning R-3327 AT-1 rat prostate tumor cells were injected into the prostate of syngenic and immunocompetent Copenhagen rats and analyzed at different time points for vascular proliferation and macrophage density. Endothelial proliferation increased with tumor size both in the tumor and importantly also in the extratumoral normal prostate tissue. Macrophages accumulated in the tumor and in the extratumoral normal prostate tissue and were most abundant in the invasive zone. Moreover, only extratumoral macrophages showed strong positive associations with tumor size and extratumoral vascular proliferation. Treatment with clodronate-encapsulated liposomes reduced the monocyte/macrophage infiltration and resulted in a significant inhibition of tumor growth. This was accompanied by a suppressed proliferation in microvessels and in the extratumoral prostate tissue also in arterioles and venules. The AT-1 tumors produced, as examined by RT(2) Profiler PCR arrays, numerous factors promoting monocyte recruitment, angiogenesis, and tissue remodeling. Several, namely, chemokine (C-C) ligand 2, fibroblast growth factor 2, matrix metalloproteinase 9, interleukin 1beta, interferon gamma, and transforming growth factor beta, were highly upregulated by the tumor in vivo compared with tumor cells in vitro, suggesting macrophages as a plausible source. In conclusion, we here show the importance of extratumoral monocytes/macrophages for prostate tumor growth, angiogenesis, and extratumoral arteriogenesis. Our findings identify tumor-associated macrophages and several chemotactic and angiogenic factors as potential targets for prostate cancer therapy.
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| 10. |
- Halin, Sofia, et al.
(author)
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Pigment epithelium-derived factor stimulates tumor macrophage recruitment and is downregulated by the prostate tumor microenvironment
- 2010
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In: Neoplasia. - : Neoplasia press. - 1522-8002 .- 1476-5586. ; 12:4, s. 336-345
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Journal article (peer-reviewed)abstract
- Pigment epithelium-derived factor (PEDF) is a potent inhibitor of angiogenesis but whether it has additional effects on the tumor microenvironment is largely unexplored. We show that overexpression of PEDF in orthotopic MatLyLu rat prostate tumors increased tumor macrophage recruitment. The fraction of macrophages expressing inducible nitric oxide synthase, a marker of cytotoxic M1 macrophages, was increased, suggesting that PEDF could enhance antitumor immunity. In addition, PEDF overexpression reduced vascular growth both in the tumor and in the surrounding normal tissue, slowed tumor growth, and decreased lymph node metastasis. Contrary, extratumoral lymphangiogenesis was increased. PEDF expression is, for reasons unknown, often decreased or lost during prostate tumor progression. When AT-1 rat prostate tumor cells, expressing high levels of PEDF messenger RNA (mRNA) and protein, were injected into the prostate, PEDF is markedly downregulated, suggesting that factors in the microenvironment suppressed its expression. One such factor could be macrophage-derived tumor necrosis factor alpha (TNFα). A fraction of the accumulating macrophages expressed TNFα, and TNFα treatment downregulated the expression of PEDF protein and mRNA in prostate AT-1 tumor cells in vitro and in the rat ventral prostate in vivo. PEDF apparently has multiple effects in prostate tumors: it suppresses angiogenesis and metastasis, but it also causes macrophage accumulation. Accumulating macrophages may inhibit tumor growth, but they may also suppress PEDF and enhance lymph angiogenesis and, in this way, eventually enhance tumor growth.
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| 11. |
- Hammarsten, Peter, 1977-
(author)
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Androgen controlled regulatory systems in prostate cancer : potential new therapeutic targets and prognostic markers
- 2008
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Doctoral thesis (other academic/artistic)abstract
- BACKGROUND: Prostate cancer is by far the most common cancer among Swedish men. Some patients have an aggressive lethal disease, but the majority of affected men have long expected survival. Unfortunately, the diagnostic tools available are insufficient in predicting disease aggressiveness. Novel prognostic markers are therefore urgently needed. Furthermore, metastatic prostate cancer is generally treated with castration, but the long-term effects are insufficient. Additional studies are therefore needed to explore how the effects of this therapy can be enhanced. Prostate growth and regression is beside testosterone controlled by locally produced regulators. Vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) are two of the major regulators in the normal prostate and in prostate tumours. MATERIALS AND METHODS: VEGF and EGFR were explored in the prostate, by treating rats with either anti-VEGF or anti-EGFR treatment during castration and testosterone-stimulated prostate growth. Rats with implanted androgen-independent prostate tumours were treated with an inhibitor of both VEGF receptor-2 (VEGFR-2) and EGFR. Stereological techniques, immunohistochemistry, western blotting and quantitative real-time PCR were used to evaluate these experiments. Furthermore, prostate tissue from untreated prostate cancer patients was used to retrospectively explore the expression of phosphorylated-EGFR (pEGFR) in relation to outcome. RESULTS: Anti-VEGF treatment during testosterone-stimulated prostate growth, inhibited vascular and prostate growth. Anti-EGFR treatment during castration and testosterone-stimulated prostate growth resulted in enhanced castration effects and inhibited prostate growth. Anti-vascular treatment of androgen-independent prostate cancer with an inhibitor of VEGFR-2 and EGFR, that targets the normal and tumour vasculature, enhanced the effects of castration. Low immunoreactivity for pEGFR in prostate epithelial cells, both in the tumour and also in the surrounding non-malignant tissue, was associated with good prognosis. CONCLUSIONS: Anti-vascular treatment, with an inhibitor of VEGFR-2 and EGFR, in combination with castration could be an effective way to treat androgen-insensitive prostate tumours. VEGF and EGFR signalling are necessary components in testosterone-stimulated prostate growth. Phosphorylation of EGFR could be a useful prognostic marker for prostate cancer patients. Tumours may affect the surrounding non-malignant tissue and pEGFR immunoreactivity in the morphologically normal prostate tissue can be used to retrieve prognostic information.
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| 12. |
- Hammarsten, Peter, 1977-, et al.
(author)
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ErbB2 Receptor Immunoreactivity in Prostate Cancer : Relationship to the Androgen Receptor, Disease Severity at Diagnosis and Disease Outcome
- 2014
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In: PLOS ONE. - : Public Library Science. - 1932-6203. ; 9:9
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Journal article (peer-reviewed)abstract
- BACKGROUND: ErbB2 is a member of the epidermal growth factor family of tyrosine kinases that is centrally involved in the pathogenesis of prostate cancer and several studies have reported that a high expression of this protein has prognostic value. In the present study, we have investigated whether tumour ErbB2 immunoreactivity (ErbB2-IR) has clinically useful prognostic value, i.e. that it provides additional prognostic information to that provided by routine clinical tests (Gleason score, tumour stage).METHODOLOGY/PRINCIPAL FINDINGS: ErbB2-IR was measured in a well-characterised tissue microarray of tumour and non-malignant samples obtained at diagnosis. Additionally, mRNA levels of ErbB2-IR in the prostate were determined in the rat following manipulation of circulating androgen levels. Tumour ErbB2-IR was significantly associated with the downstream signalling molecule phosphorylated-Akt and with the cell proliferation marker Ki-67. The significant association of tumour ErbB2-IR with the Gleason score at diagnosis was lost when controlled for the association of both parameters with Ki-67. In the rat prostate, mRNA for ErbB2 was inversely associated with circulating androgen levels. There was no association between ErbB2-IR and the androgen receptor (AR)-IR in the tumours, but an interaction between the two parameters was seen with respect to their association with the tumour stage. Tumour ErbB2-IR was confirmed to be a prognostic marker for disease-specific survival, but it did not provide significant additive information to the Gleason score or to Ki-67.CONCLUSIONS/SIGNIFICANCE: It is concluded that tumour ErbB2-IR is of limited clinical value as a prognostic marker to aid treatment decisions, but could be of pathophysiological importance in prostate cancer.
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| 13. |
- Hammarsten, Peter, et al.
(author)
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Low levels of phosphorylated epidermal growth factor receptor in nonmalignant and malignant prostate tissue predict favorable outcome in prostate cancer patients.
- 2010
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In: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 16:4, s. 1245-1255
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Journal article (peer-reviewed)abstract
- PURPOSE: To explore if the expression of phosphorylated epidermal growth factor receptor (pEGFR) in nonmalignant and malignant prostate tissue is a potential prognostic marker for outcome in prostate cancer patients. EXPERIMENTAL DESIGN: We used formalin-fixed tissues obtained through the transurethral resection of the prostate from 259 patients diagnosed with prostate cancer after the transurethral resection of the prostate, and patients were then followed with watchful waiting. Tissue microarrays of nonmalignant and malignant prostate tissue were stained with an antibody against pEGFR. The staining pattern was scored and related to clinicopathologic parameters and to outcome. RESULTS: Low phosphorylation of EGFR in prostate epithelial cells, both in the tumor and surprisingly also in the surrounding nonmalignant tissue, was associated with significantly longer cancer-specific survival in prostate cancer patients. This association remained significant when Gleason score and local tumor stage were added together with pEGFR to a Cox regression model. Tumor epithelial pEGFR immunoreactivity was significantly correlated to tumor cell proliferation, tumor vascular density, and nonmalignant epithelial pEGFR immunoreactivity. Patients with metastases had significantly higher immunoreactivity for tumor and nonmalignant epithelial pEGFR compared with patients without metastases. CONCLUSIONS: Low pEGFR immunoreactivity is associated with the favorable prognosis in prostate cancer patients and may provide information about which patients with Gleason score 6 and 7 tumors that will survive their disease even without treatment. Changes in the nonmalignant tissue adjacent to prostate tumors give prognostic information.
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| 14. |
- Häggström Rudolfsson, Stina, et al.
(author)
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Localized expression of angiopoietin 1 and 2 may explain unique characteristics of the rat testicular microvasculature.
- 2003
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In: Biology of Reproduction. - : Oxford University Press (OUP). - 0006-3363 .- 1529-7268. ; 69:4, s. 1231-7
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Journal article (peer-reviewed)abstract
- The testicular vasculature is unique in several ways. The unfenestrated endothelial cells constitute one part of the blood-testis barrier, and testicular microvessels are normally resistant to inflammation mediators. At the same time that angiogenic factors and inflammation mediators are constitutively produced, the proportion of proliferating endothelial cells is considerably higher than in other organs, but new blood vessels are not formed. Hormonal stimulation of the testis with hCG increase endothelial cell proliferation, vascular permeability, and sensitivity to locally injected inflammation mediators. In the present study, we examined whether local expression of angiopoietin (ang) 1, an inhibitor of vascular leakage and sprouting angiogenesis, and its antagonist, ang 2, could be involved in establishing this vascular phenotype. Using reverse transcription-polymerase chain reaction and immunohistochemistry, we demonstrate that testicular vascular endothelial growth factor-A (VEGF-A), ang 1, ang 2, and the ang-receptor tie 2 are expressed in the testis and that hormonal stimulation with hCG is accompanied by increased expression of VEGF-A and ang 2. The ang 1 protein is expressed in testicular microvessels under basal conditions, and it is largely unaffected after hCG stimulation. Expression of ang 2 in microvessels, in contrast, is low under basal conditions and is up-regulated by hCG. Intratesticular injection of human recombinant ang 1 protein inhibits hCG-induced increase in vascular permeability. Injection of ang 2 in the testis increases endothelial cell proliferation and the volume of the interstitial space. We therefore suggest that ang 1 stabilizes testicular microvessels under basal conditions and that a shift in this balance caused by increased ang 2, together with increased VEGF-A, allows vascular leakage, high endothelial cell proliferation, and presumably, vascular growth after hormonal stimulation.
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- Johansson, Anna, et al.
(author)
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A stroma targeted therapy enhances castration effects in a transplantable rat prostate cancer model.
- 2007
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In: The Prostate. - : Wiley. - 0270-4137 .- 1097-0045. ; 100, s. 6-6
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Journal article (peer-reviewed)abstract
- BACKGROUND: Castration results in a major involution of the normal prostate gland. This process is initiated by effects in the prostate stroma and vasculature. Castration-induced regression of androgen sensitive prostate tumors is however less prominent and hypothetically this could be related to a limited stromal/vascular response. We therefore used animal tumor models to explore the importance of stroma and vascular effects, and if castration effects could be enhanced by a simultaneous therapy targeting the tumor stroma. METHODS: Using rats with Dunning PAP and H tumors, stereological methods, immunohistochemistry, and Western blotting, we studied the tumor response 7 and 28 days after castration and after the addition of stroma targeted therapies. RESULTS: In the normal ventral prostate (VP) nuclear androgen receptors (AR) were rapidly downregulated after castration. In contrast, the Dunning tumors downregulated the AR in the cancerous epithelium, but not in the surrounding stroma. Vascular regulators such as the angiopoietins, tie 2, and PDGF-Rbeta were not decreased in the stroma after castration, as observed in the VP, creating an environment that prevents vascular involution. When a tumor stroma targeted therapy inhibiting the tie 2 receptor and the PDGF-Rbeta simultaneously was added to castration it resulted in a decreased vascular density, increased tumor cell apoptosis and decreased tumor growth compared to castration alone. CONCLUSIONS: The stroma in highly differentiated androgen sensitive Dunning tumors is apparently androgen insensitive. If this unresponsive stroma is targeted the effects of castration can be enhanced.
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- Johansson, Anna, et al.
(author)
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Targeting castration-induced tumour hypoxia enhances the acute effects of castration therapy in a rat prostate cancer model
- 2011
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In: BJU International. - 1464-4096 .- 1464-410X. ; 107:11, s. 1818-1824
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Journal article (peer-reviewed)abstract
- OBJECTIVE: • To explore the effects of castration therapy, the standard treatment for advanced prostate cancer, in relation to tumour hypoxia and to elicit its importance for the short- and long-term therapeutic response. MATERIAL AND METHODS: • We used the androgen-sensitive rat Dunning H prostate tumour model that transiently responds to castration treatment followed by a subsequent relapse, much like the scenario in human patients. • Tumour tissues were analysed using stereological methods in intact, 1 and 7 days after castration therapy. RESULTS: • Hypoxia was transiently up-regulated after castration therapy and correlated with the induction of tumour cell apoptosis. • When castration therapy was combined with tirapazamine (TPZ), a drug that targets hypoxic cells and the vasculature, the effects on tumour cell apoptosis and tumour volume were enhanced in comparison to either castration or TPZ alone. CONCLUSION: • The present study suggests that castration-induced tumour hypoxia is a novel target for therapy.
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- Ljungberg, Börje, et al.
(author)
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Tumour vascular endothelial growth factor (VEGF) mRNA in relation to serum VEGF protein levels and tumour progression in human renal cell carcinoma
- 2003
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In: Urological research. - : Springer-Verlag New York. - 0300-5623 .- 1434-0879. ; 31:5, s. 335-40
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Journal article (peer-reviewed)abstract
- Angiogenesis is gaining interest because of its importance in tumour growth and metastasis. Renal cell carcinoma (RCC) is known to be a well-vascularized tumour. The aim of this study was to evaluate the expression of VEGF mRNA and receptor flt-1 mRNA (VEGF R1) in a clinical material of RCCs compared with clinicopathological variables and serum VEGF levels. Total RNA was extracted from snap-frozen tumour tissue obtained from 61 patients. Expression of mRNA for VEGF121, VEGF165 and flt-1 were analysed using quantitative RT-PCR. Relative VEGF mRNA levels, corrected for corresponding cyclophilin value, were related to stage, grade, RCC type and survival time. Serum VEGF165 protein was analysed using a quantitative ELISA. Papillary RCC had significantly lower VEGF121 and flt-1 mRNA levels compared with conventional RCC (p=0.001). VEGF121 mRNA levels were significantly lower in locally advanced tumours in relation to tumours limited to the kidney and those with metastatic disease (p=0.047 and p=0.036). This statistical difference disappeared when only conventional RCCs were evaluated. No association was found between VEGF mRNA levels and nuclear grade. Patients with lower VEGF121 mRNA levels had significantly longer survival time compared with those with higher levels (when adjusted to stage, p=0.0097, log rank test). There was an inverse relation between VEGF165 mRNA and serum VEGF165 levels. The trend to lower VEGF121 mRNA levels in locally advanced RCC indicate that angiogenic activity and degradation might be up-regulated in tumours with a high ability to invade. The association with tumour progression shows that VEGF is a promising angiogenic factor especially important in conventional RCCs. VEGF expression might possibly be of help to identify RCCs susceptible for anti-angiogenic therapies.
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| 24. |
- Pätzold, Jens, et al.
(author)
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Exclusive measurements of the pp --> pp pi+pi- reaction
- 2002
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In: Proc. 9th Int. Symp. on Meson-Nucleon Physics and the Structure of the Nucleon, MENU 2001, Washington D.C., USA, 2001., piN Newsletter. ; , s. 370-
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Conference paper (peer-reviewed)
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- Rudolfsson, Stina Häggström, et al.
(author)
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Hypoxia drives prostate tumour progression and impairs the effectiveness of therapy, but can also promote cell death and serve as a therapeutic target.
- 2009
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In: Expert opinion on therapeutic targets. - : Informa Healthcare. - 1744-7631 .- 1472-8222. ; 13:2, s. 219-225
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Journal article (peer-reviewed)abstract
- Hypoxia is common in prostate tumours, promoting tumour progression and impairing treatment responses. Hypoxia stimulates angiogenesis but blood vessels formed in tumours are functionally abnormal so the tissue remains hypoxic. Castration treatment is the standard therapy for advanced prostate cancer. In non-malignant prostate tissue castration-induced epithelial cell death is in part mediated by vascular insult and acute hypoxia, but in prostate tumours the cell death response is less prominent and the tumours will eventually relapse. The effect of androgen ablation therapy should therefore be enhanced by additional targeting of the vasculature and hypoxic tumour cells. However if castration fails to kill a sufficiently large number of cells it could by inducing hypoxia make the situation worse. Androgen ablation treatment, may, after the initial vascular insult, result in temporary vascular normalisation and transiently increased tissue oxygen levels. During this time window, which needs to be better defined, the efficacy of cytotoxic drug and radiation treatments are probably enhanced. In order to allow development of more effective treatment strategies for advanced prostate cancer we need to understand the role of hypoxia in prostate cancer progression and treatment responses. With this knowledge we can properly tailor and time additional treatments with androgen ablation.
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