Thrombospondin-1, vascular endothelial growth factor expression and microvessel density in renal cell carcinoma and their relationship with multifocality

Correlation between TSP-1, TGF-β and PPAR-γ expression levels and glioma microvascular density

Gliomas are the most common type of primary tumor in the central nervous system and are characterized by abundant capillary angiogenesis. It is important to study the underlying molecular mechanisms of angiogenesis in order to aid the identification of potential therapeutic targets. The aim of the current study was to investigate the expression levels of thrombospondin-1 (TSP-1), transforming growth factor-β (TGF-β) and peroxisome proliferator-activated receptor-γ (PPAR-γ) in gliomas, and determine their relationships with angiogenesis. Immunohistochemical methods were used to detect TSP-1, TGF-β and PPAR-γ expression levels and to assess microvascular density (MVD) in 99 glioma tissue samples of various grades. The total positive expression rates of TSP-1 and PPAR-γ were 78.4 and 94.1% in low-grade gliomas and 45.8 and 39.6% in high-grade gliomas. These values suggest that their expression negatively correlated with tumor grade. However, TGF-β expression positively correlated with tumor grade; the total positive expression rate of TGF-β in high-grade gliomas (93.8%) was significantly increased compared with that in low-grade gliomas (43.1%). The MVD in the low-grade group was 28±7.2 vessels/field, which was significantly lower than in the high-grade group (45±6.2 vessels/field). TSP-1 and PPAR-γ expression levels were negatively correlated with MVD (P<0.05), while the TGF-β expression level was positively correlated with MVD (P<0.05). These results indicate that the TSP-1, TGF-β and PPAR-γ expression levels in gliomas are correlated with MVD, which suggests that these proteins may be involved in the regulation of glioma angiogenesis.

Thrombospondin-1 in urological cancer: pathological role, clinical significance, and therapeutic prospects

Angiogenesis is an important process for tumor growth and progression of various solid tumors including urological cancers. Thrombospondins (TSPs), especially TSP-1, are representative “anti”-angiogenic molecules and many studies have clarified their pathological role and clinical significance in vivo and in vitro. In fact, TSP-1 expression is associated with clinicopathological features and prognosis in many types of cancers. However, TSP-1 is a multi-functional protein and its biological activities vary according to the specific tumor environments. Consequently, there is no general agreement on its cancer-related function in urological cancers, and detailed information regarding regulative mechanisms is essential for a better understanding of its therapeutic effects and prognostic values. Various “suppressor genes” and “oncogenes” are known to be regulators and TSP-1-related factors under physiological and pathological conditions. In addition, various types of fragments derived from TSP-1 exist in a given tissue microenvironment and TSP-1 derived-peptides have specific activities. However, a detailed pathological function in human cancer tissues is not still understood. This review will focus on the pathological roles and clinical significance of TSP-1 in urological cancers, including prostate cancer, renal cell carcinoma, and urothelial cancer. In addition, special attention is paid to TSP-1-derived peptide and TSP-1-based therapy for malignancies.

Vasohibin-1 is a new predictor of disease-free survival in operated patients with renal cell carcinoma

Background

Vasohibin-1 (VASH1) is an endothelium-produced angiogenesis inhibitor. Renal cell carcinoma is highly vascularised, but the significance of endogenous VASH1 in renal cell carcinoma has not been defined.

Aims

To identify VASH1 expression and its possible relationship with various clinicopathological factors and prognosis in renal cell carcinoma.

Methods

A retrospective analysis of 122 tumours obtained from 118 consecutive patients with renal cell carcinoma was performed. The expression patterns of VASH1, CD31, vascular endothelial growth factor (VEGF) and VEGF receptor type 2 (VEGFR2) were examined immunohistochemically and their relationships with clinicopathological factors were analysed.

Results

Microvessel density, VASH1 and VEGFR2 expression were significantly higher in clear cell carcinoma than in other subtypes. The VEGF expression pattern differed significantly between clear cell carcinoma and other histological subtypes. VASH1, pT factor and TNM stage were significantly associated with disease-free survival (p=0.030, p = 0.0012 and p = 0.0018, respectively). Cox models of multivariable disease-free survival analyses indicated that VASH1 and stage are independent prognostic factors (p=0.019 and p = 0.024).

Conclusions

VASH1 expression may be useful for estimating the prognosis of renal cell carcinoma. Further studies of the role of VASH1 in renal cell carcinoma involving larger sample sizes are warranted.

Temporal profile of astrocytes and changes of oligodendrocyte-based myelin following middle cerebral artery occlusion in diabetic and non-diabetic rats

The long-term impacts of cerebral ischemia and diabetic ischemia on astrocytes and oligodendrocytes have not been defined. The objective of this study is to define profile of astrocyte and changes of myelin in diabetic and non-diabetic rats subjected to focal ischemia.Focal cerebral ischemia of 30-min duration was induced in streptozotocin-induced diabetic and vehicle-injected normoglycemic rats. The brains were harvested for immunohistochemistry of glial fibrillary acidic protein (GFAP) and 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) at various reperfusion endpoints ranging from 30 min up to 28 days. The results showed that activate astrocytes were observed after 30 min and peaked at 3 h to 1 day after reperfusion in ischemic penumbra, and peaked at 7 days of reperfusion in ischemic core. Diabetes inhibited the activation of astrocytes in ischemic hemisphere. Demyelination occurred after 30 min of reperfusion in ischemic core and peaked at 1 day. Diabetes caused more severe demyelination compared with non-diabetic rats. Remyelination started at 7 days and completed at 14 and 28 days in ischemic region. Diabetes inhibited the remyelination processes. It is concluded that ischemia activates astrocytes and induces demyelination. Diabetes inhibits the activation of astrocytes, exacerbates the demyelination and delays the remyelination processes. These may contribute to the detrimental effects of hyperglycemia on ischemic brain damage.

The expression of thrombospondin-1 and p53 in clear cell renal cell carcinoma: its relationship to angiogenesis, cell proliferation and cancer specific survival

PURPOSE

We evaluated possible associations among thrombospondin-1, p53 expression, microvessel density, cell proliferation index, nuclear grade, tumor stage and continuously coded tumor size in clear cell renal cell carcinoma. The value of thrombospondin-1 as a prognostic marker in clear cell renal cell carcinoma was examined.

MATERIALS AND METHODS

A total of 172 consecutive patients with clear cell renal cell carcinoma treated with radical nephrectomy were initially enrolled in the study. However, due to technical problems and lack of material 12 cases were excluded from analysis. A total of 68 patients (43%) died of renal cell carcinoma and 46 (29%) died of other diseases. Median followup for the surviving 42 patients (29%) was 13.8 years. The expression of thrombospondin-1, Ki-67 (proliferation index), p53 and microvessel density were analyzed without knowledge of the clinical outcome on formalin fixed, paraffin embedded tissues.

RESULTS

Low expression of thrombospondin-1 was significantly associated with advanced stage (p <0.001), high nuclear grade (p = 0.001), positive p53 status (p <0.001), high proliferation index (p = 0.001), high microvessel density (p = 0.036) and tumor progression (p = 0.006). On univariate analysis thrombospondin-1, microvessel density, proliferation index, p53 over expression, TNM stage, Fuhrman nuclear grade (p <0.001) and continuously coded tumor size (p = 0.002) had a significant impact on survival. Multivariate analysis revealed TNM stage, thrombospondin-1, p53, Ki-67 (proliferation index) and microvessel density were independent predictors of cancer specific survival.

CONCLUSIONS

Thrombospondin-1 expression is strongly associated with prognostic tumor features in clear cell renal cell carcinoma and is an independent prognostic factor for cancer specific survival. Our findings revealed a significant correlation among p53, proliferation index, microvessel density and thrombospondin-1 expression, and indicate that thrombospondin-1 may have an impact on angiogenesis, proliferation and tumor aggressiveness in clear cell renal cell carcinoma.

Prognostic role of tumor necrosis, microvessel density, vascular endothelial growth factor and hypoxia inducible factor-1alpha in patients with clear cell renal carcinoma after radical nephrectomy in a long term follow-up

Angiogenesis is a critical step in the growth, invasive progression and metastatic spread of solid tumors. We investigated the importance of tumor necrosis, and microvessel density (MVD), vascular endothelial growth factor (VEGF) and hypoxia inducible factor 1alpha (HIF-1alpha) immunohistochemical expression in a large series of clear cell renal carcinomas treated with radical nephrectomy and assessed the prognostic value of their expression in terms of patient survival at long-term followup. Fifty patients with clear cell RCC were examined. The features considered when evaluating the patients were age, tumor size and grade, intratumoral vascular and renal capsula invasion, histological necrosis, and MVD, vascular and tumoral cell VEGF, and vascular, tumoral cytoplasmic and nuclear HIF-1alpha expression on the histologic specimens. All considered parameters were correlated with patient specific survival. Mean age was 62.06 +/- 6.8 years. Median follow-up was 191.66 months; median survival was 120.86 months. Twenty-one patients developed metastases in the follow-up. Tumor necrosis, microvascular invasion and renal capsula infiltration are more likely to occur in high stage and grade RCC; cytoplasmic HIF-1alpha is highly expressed in high grade RCC. Survival is dependent upon tumor stage and grade, the presence of intratumoral vascular invasion and capsular infiltration, and tumor necrosis; MVD also resulted as being an important prognostic factor. VEGF and HIF-1alpha correlate with prognosis in high stage tumors where VEGF is the most important independent prognostic factor for cancer specific death. The histological and immunohistochemical parameters considered in our study can influence disease recurrence and survival in RCC.

Long-term outcome of multiple ipsilateral renal tumours found at the time of planned nephron-sparing surgery

OBJECTIVE

To evaluate patients with multiple ipsilateral renal tumours and to determine outcomes of nephron-sparing surgery (NSS) and radical nephrectomy (RN), as the treatment of unrecognized sporadic multifocal tumours at NSS presents a surgical dilemma.

PATIENTS AND METHODS

In all, 104 patients had surgery between 1970 and 2003 for sporadic multiple ipsilateral renal tumours, at least one of which was renal cell carcinoma (RCC); 114 were treated with RN and 26 with NSS. Cancer-specific survival (CSS) was estimated using the Kaplan-Meier method.

RESULTS

More patients treated with NSS had a solitary kidney than those undergoing RN (six, 23%, vs none, P < 0.001). Seventeen of the 114 having RN died from RCC at a median (range) of 3.4 (0.25-10.3) years after RN. The estimated 5-year CSS was 90.5%. There was metachronous recurrence in nine patients at a median of 5.6 (1-14 ) years after. Two of the 26 patients having NSS died from RCC at 1 and 6 years after NSS; the 5-year CSS was 95.8%. There was local or metachronous recurrence in three patients at 7 months to 6 years after surgery; all three were alive at the last follow-up. In 26 (23%) of the 114 patients treated with RN, only one tumour was RCC.

CONCLUSION

Patients undergoing either RN or NSS for multiple ipsilateral renal tumours have a favourable CSS. A planned NSS is safe if small satellite lesions are resectable.

Prognostic factors in a prospective series of papillary renal cell carcinoma

OBJECTIVE

To prospectively assess the clinical outcome of a series of papillary renal cell carcinomas (PRCCs) to identify possible prognostic clinical variables and tumour markers, as previous retrospective series of PRCC do not provide unanimous results on the prognostic utility of clinicopathological variables.

PATIENTS AND METHODS

Forty-six patients with PRCC (median follow-up 40 months) diagnosed in one institution from 1989 to 2002 were prospectively followed until May 2006. The pathology was reviewed, the PRCC subtyped (type 1 and 2) and immunohistochemistry assessed for MIB-1, vascular endothelial growth factor (VEGF), CD31 and c-met oncogenic protein, by a referee pathologist. Prognostic values were estimated by fitting a Cox model.

RESULTS

The 5-year survival rate was 49.5%; type 2 histology was predominant and was almost significant in the univariate analysis. Stage and MIB-1 were significant prognostic factors only in the univariate model, while the Cox model identified only the Fuhrman grade as an independent predictor of survival (hazard ratio 3.054; P = 0.007). MET expression, CD31 and VEGF had no prognostic utility.

CONCLUSION

These patients with PRCC followed prospectively fared worse than in previously reported series. The Fuhrman grade was the sole independent predictor of survival.

Evaluation of peri-operative peripheral and renal venous levels of pro- and anti-angiogenic factors and their relevance in patients with renal cell carcinoma

OBJECTIVE

To evaluate peri-operative peripheral and renal venous plasma levels of vascular endothelial growth factor (VEGF), platelet-derived growth factor type BB (PDGF-BB), transforming growth factor (TGF)-beta1, endostatin, and thrombospondin-1 (TSP-1) in relation to pathological variables and prognosis, as pro- and anti-angiogenic factors are important for tumour growth and treatment of patients with renal cell carcinoma (RCC).

PATIENTS AND METHODS

The study included 74 consecutive patients with sporadic RCC who had tumour nephrectomy. Peripheral venous blood was drawn 1 day before, immediately and 1, 3 and 5 days after surgery. Renal venous blood was collected in a subgroup of 33 patients during surgery. The variables were analysed using quantitative enzyme-linked immunoassay kits, and associated with pathological variables and disease-specific survival.

RESULTS

Soon after surgery, peripheral venous VEGF, PDGF-BB and TGF-beta1 levels were decreased, whereas endostatin levels were significantly increased. Renal venous VEGF, PDGF-BB and TGF-beta1 levels were higher than in the general venous blood pool. Renal venous VEGF levels were correlated with tumour diameter and associated with grade and vascular invasion. After a mean follow-up of 30 months, higher peripheral preoperative, early peripheral postoperative and renal venous VEGF levels were associated with a poorer prognosis. However, in a multivariate analysis only Tumour-Node-Metastasis stage and Eastern Cooperative Oncology Group performance status were independent prognosticators of disease-specific survival.

CONCLUSIONS

Circulating pro- and anti-angiogenic factors change early after nephrectomy. VEGF, PDGF-BB and TGF-beta1 are higher in the renal vein than in the general venous blood pool. Higher renal venous and peripheral levels of VEGF might be associated with a poorer prognosis.

Microvessel density and regulators of angiogenesis in malignant and nonmalignant prostate tissue

The aim of this study was to investigate the relationship between microvessel density (MVD), positive and negative angiogenic factors, and established prognostic factors in prostate cancer (PC), and, to clarify the effect of angiogenic factors to angiogenesis. The vascularization of neoplastic, non-neoplastic prostate tissue was determined by CD34 immunostaining. Angiogenetic mediators VEGF, bFGF, TSP-1, and p53 were studied by immunohistochemistry. Neovascularization and p53, VEGF, and TSP-1 expressions of tumorous tissue were higher than non-tumorous tissue. The bFGF expression in these tissues was not different. The p53 expression was not correlated with the expressions of VEGF, bFGF, and TSP-1 in PC. Our results demonstrate a significant increase in MVD, VEGF, TSP-1, and p53 expressions in prostate tumorigenesis. The pretreatment sPSA was the only parameter demonstrating significant correlation with tumor grade and may have a value in the prediction of aggressive tumor behavior in PC.

The phosphoinositide 3-kinase/Akt pathway: a new target in human renal cell carcinoma therapy

Metastatic renal cell carcinoma is resistant to current therapies. The phosphoinositide 3-kinase (PI3K)/Akt signaling cascade induces cell growth, cell transformation, and neovascularization. We evaluated whether targeting this pathway could be of therapeutic value against human renal cell carcinoma. The activation of the PI3K/Akt pathway and its role in renal cell carcinoma progression was evaluated in vitro in seven human cell lines by Western blot, cell counting, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, terminal deoxyribonucleotide transferase-mediated nick-end labeling assays, and fluorescence-activated cell sorting analysis, using two PI3K inhibitors, LY294002 and wortmannin, as well as by transfection with various Akt constructs and through Akt knockdown by small interfering RNA (siRNA). In vivo nude mice bearing human renal cell carcinoma tumor xenografts were treated with LY294002 (75 mg/kg/wk, 4 weeks, i.p.). Tumor growth was measured and tumors were subjected to Western blot and immunohistochemical analysis. Akt was constitutively activated in all cell lines. Constitutive phosphorylation of glycogen synthase kinase-3 (GSK-3) was observed in all cell lines, whereas forkhead transcription factor and mammalian target of rapamycin, although expressed, were not constitutively phosphorylated. Exposure to LY294002 or wortmannin decreased Akt activation and GSK-3 phosphorylation and reduced cell growth by up to 70% through induction of cell apoptosis. These effects were confirmed by transfection experiments with Akt constructs or Akt siRNA. Importantly, LY294002 induced up to 50% tumor regression in mice through tumor cell apoptosis. Tumor neovascularization was significantly increased by LY294002 treatment. Blood chemistries showed no adverse effects of the treatment. Our results suggest an important role of PI3K/Akt inhibitors as a potentially useful treatment for patients with renal cell carcinoma.

Thrombospondin and vascular endothelial growth factor are cyclically expressed in an inverse pattern during bovine ovarian follicle development

Angiogenesis does not normally occur in most adult tissues. However, in the ovary, there are cyclical vascular changes including angiogenesis that involve the interaction of numerous cytokines and growth factors. Angiogenic processes are regulated by a balance between pro- and antiangiogenic factors. The purpose of this study was to determine the expression of the antiangiogenic thrombospondin family and proangiogenic vascular endothelial growth factor (VEGF) in various sizes of healthy bovine follicles. Ovaries were collected from slaughterhouse animals and healthy follicles were sorted based on size (< 0.5 cm, small; 0.5-1.0 cm, medium; >1.0 cm, large). Thrombospondin (TSP) protein levels were significantly higher in small follicles. Immunohistochemistry confirmed the granulosa layer as the primary area within the follicle involved in TSP generation and that small follicles had the highest proportion of immunopositive cells. TSP-1 and -2 mRNA levels were significantly higher in small follicles than either medium or large follicles. TSP colocalized with CD36 on granulosa cells (GC) in the follicle and in cultured cells. In contrast with TSP, VEGF expression increased during growth and development of the follicle. FSH stimulated GC expression of TSP, while LH had no effect. In summary, TSP-1 and -2 were coordinately expressed in the extravascular compartment of the ovary during early follicle development. VEGF was inversely expressed, with expression increasing as follicles developed. Regulated expression and localization of these proteins suggests that they may be involved in regulating growth and development of the follicle in a novel fashion.

Prognostic Value of Multifocality on Progression and Survival in Localized Renal Cell Carcinoma

OBJECTIVE

Incidence of multifocality in Renal Cell Carcinoma (RCC) is estimated at between 5 and 25%. Multifocality has been largely studied because of the growing interest in conservative surgery which is a risk of local recurrence. The aim of this study is to evaluate the relationship between multifocality and other prognostic parameters and whether it is an independent prognostic factor.

MATERIAL AND METHODS

From 1980 to 1990, 255 patients (median age: 60.9 years) were treated by radical nephrectomy for pT1 to pT3b N0M0 RCC. The median follow-up time was 183 months. Multifocality was defined as the existence of at least one other tumoral localization, macroscopically and microscopically diagnosed as renal cell carcinoma, in the same kidney. Studied parameters were: age, sex, side, size, stage, Fuhrman's grade, capsular invasion, renal vein involvement and microvascular invasion. Survival was assessed with Kaplan-Meier and Cox models.

RESULTS

37 cases of multifocal RCC were diagnosed (14.5%). There was only a significant correlation with stage (p=0.002) and with capsular invasion (p=0.002). No other factor was correlated with multifocality. It had no influence on the risk of metastatic progression, overall or specific survival.

CONCLUSION

There is a significant correlation between capsular invasion and multifocality that has to be considered before proposing conservative surgery for a localized RCC. Multifocality has no influence on survival or metastatic progression in case of radical nephrectomy.