Prognostic implications of lymphangiogenesis in muscle-invasive transitional cell carcinoma of the bladder

Expression of Claudin-4 and D2-40 and their significance in prostatic adenocarcinoma

BACKGROUND

Claudins are a clan of proteins that are the most important component of tight junctions. The claudin-4 expression has been linked to tumour cell invasion and progression in a variety of primary malignancies. Evaluation of lymphovascular density (LVD) correlates with tumour aggressiveness and may correlate with prognosis. D2-40 is a highly specific marker of lymphatic vessels.

AIMS

To evaluate the claudin-4 expression in relation to LVD by D2-40 expression and with clinicopathological parameters in prostatic adenocarcinoma.

SETTINGS AND DESIGN

Prospective study.

MATERIALS AND METHODS

39 cases of prostatic adenocarcinoma were taken, the D2-40 and claudin-4 immunohistochemical stains were performed and correlation was done with clinicopathological parameters.

STATISTICAL ANALYSIS USED

Statistical analyses such as mean, median, standard deviation, Mann-Whitney U test, Fischer exact test, Spearman's rank-order correlation coefficient, Chi-square test and T-test were used.

RESULTS

The claudin-4 expression was seen higher in cases with higher Gleason score but it was statistically non-significant (P = 0.778). The claudin-4 expression did not correlate with any clinicopathological parameters. LVD in the peritumoral area was significantly higher as compared to the intratumoral area (P = 0.005). Intratumoral LVD and perineural invasion were found to be statistically significant (P = 0.048).

CONCLUSION

The claudin-4 expression may correlate with adverse prognostic parameters. Higher lymphatic vessels can be responsible for the higher metastatic potential of prostatic adenocarcinomas.

Predictive Nomogram and Risk Factors for Lymph Node Metastasis in Bladder Cancer

Lymph node metastasis (LNM) is an important prognostic factor for bladder cancer (BCA) and determines the treatment strategy. This study aimed to determine related clinicopathological factors of LNM and analyze the prognosis of BCA. A total of 10,653 eligible patients with BCA were randomly divided into training or verification sets using the 2004-2015 data of the Surveillance, Epidemiology, and End Results database. To identify prognostic factors for the overall survival of BCA, we utilized the Cox proportional hazard model. Independent risk factors for LNM were evaluated via logistic regression analysis. T-stage, tumor grade, patient age and tumor size were identified as independent risk factors for LNM and were used to develop the LNM nomogram. The Kaplan-Meier method and competitive risk analyses were applied to establish the influence of lymph node status on BCA prognosis. The accuracy of LNM nomogram was evaluated in the training and verification sets. The areas under the receiver operating characteristic curve (AUC) showed an effective predictive accuracy of the nomogram in both the training (AUC: 0.690) and verification (AUC: 0.704) sets. In addition, the calibration curve indicated good consistency between the prediction of deviation correction and the ideal reference line. The decision curve analysis showed that the nomogram had a high clinical application value. In conclusion, our nomogram displayed high accuracy and reliability in predicting LNM. This could assist the selection of the optimal treatment for patients.

circEHBP1 promotes lymphangiogenesis and lymphatic metastasis of bladder cancer via miR-130a-3p/TGFβR1/VEGF-D signaling

Lymphatic metastasis constitutes a leading cause of recurrence and mortality in bladder cancer. Accumulating evidence indicates that lymphangiogenesis is indispensable to trigger lymphatic metastasis. However, the specific mechanism is poorly understood. In the present study, we revealed a pathway involved in lymphatic metastasis of bladder cancer, in which a circular RNA (circRNA) facilitated lymphangiogenesis in a vascular endothelial growth factor C (VEGF-C)-independent manner. Novel circRNA circEHBP1 was markedly upregulated in bladder cancer and correlated positively with lymphatic metastasis and poor prognosis of patients with bladder cancer. circEHBP1 upregulated transforming growth factor beta receptor 1 (TGFBR1) expression through physically binding to miR-130a-3p and antagonizing the suppression effect of miR-130a-3p on the 3′ UTR region of TGFBR1. Subsequently, circEHBP1-mediated TGFβR1 overexpression activated the TGF-β/SMAD3 signaling pathway, thereby promoting the secretion of VEGF-D and driving lymphangiogenesis and lymphatic metastasis in bladder cancer. Importantly, administration of VEGF-D neutralizing antibodies remarkably blocked circEHBP1-induced lymphangiogenesis and lymphatic metastasis in vivo. Our findings highlighted that the circEHBP1/miR-130a-3p/TGFβR1/VEGF-D axis contributes to lymphangiogenesis and lymphatic metastasis of bladder cancer independent of VEGF-C, which might lead to the development of circEHBP1 as a potential biomarker and promising therapeutic target for lymphatic metastasis in bladder cancer.

Exosomal long noncoding RNA LNMAT2 promotes lymphatic metastasis in bladder cancer

Patients with bladder cancer (BCa) with clinical lymph node (LN) metastasis have an extremely poor prognosis. VEGF-C has been demonstrated to play vital roles in LN metastasis in BCa. However, approximately 20% of BCa with LN metastasis exhibits low VEGF-C expression, suggesting a VEGF-C-independent mechanism for LN metastasis of BCa. Herein, we demonstrate that BCa cell-secreted exosome-mediated lymphangiogenesis promoted LN metastasis in BCa in a VEGF-C-independent manner. We identified an exosomal long noncoding RNA (lncRNA), termed lymph node metastasis-associated transcript 2 (LNMAT2), that stimulated human lymphatic endothelial cell (HLEC) tube formation and migration in vitro and enhanced tumor lymphangiogenesis and LN metastasis in vivo. Mechanistically, LNMAT2 was loaded to BCa cell-secreted exosomes by directly interacting with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1). Subsequently, exosomal LNMAT2 was internalized by HLECs and epigenetically upregulated prospero homeobox 1 (PROX1) expression by recruitment of hnRNPA2B1 and increasing the H3K4 trimethylation level in the PROX1 promoter, ultimately resulting in lymphangiogenesis and lymphatic metastasis. Therefore, our findings highlight a VEGF-C-independent mechanism of exosomal lncRNA-mediated LN metastasis and identify LNMAT2 as a therapeutic target for LN metastasis in BCa.

Heterogeneous nuclear ribonucleoprotein (hnRNPL) in cancer

Heterogeneous nuclear ribonucleoprotein L (hnRNPL) is a type of RNA binding protein that is mainly located in the nucleus. hnRNPL protein, encoded by the gene located at 19q13.2, is an important member of the hnRNP family. In recent years, studies have shown that hnRNPL is highly expressed in a variety of tumors and plays a vital role in tumor progression. hnRNPL promotes various biological processes of tumor cells, including proliferation, migration and invasion. In this review, we discuss the clinical significance of hnRNPL by reviewing the mechanism of hnRNPL in the tumorigenesis of various cancers.

Predictive value of lymphangiogenesis and proliferation markers on mRNA level in urothelial carcinoma of the bladder after radical cystectomy

OBJECTIVE

To evaluate the mRNA expression of lymphangiogenesis and proliferation markers and to examine its association with histopathological characteristics and clinical outcome in patients with urothelial carcinoma of the bladder (UCB) after radical cystectomy (RC).

PATIENTS AND METHODS

Gene expression analysis of the vascular endothelial growth -C and -D (VEGF-C/-D), its receptor VEGF receptor-3 (VEGFR-3), MKI67, and RACGAP1 was performed in 108 patients after radical cystectomy and their correlation with clinical-pathological parameters was investigated. Uni- and multivariate regression analyses were used to identify predictors for cancer-specific survival (CSS), recurrence-free survival (RFS) and overall survival (OS) after RC.

RESULTS

The expression of RACGAP1 and VEGFR-3 showed an association with a higher pT stage (P = 0.049; P = 0.009). MKI67 showed an association with a high-grade urothelial carcinoma of the bladder (P = 0.021). VEGFR-3 expression was significantly associated with the presence of lymphovascular invasion (LVI) (P = 0.016) and lymph node metastases (pN+) (P = 0.028). With the univariate analysis, overexpression of VEGFR-3 (P = 0.029) and the clinical-pathological parameters pT stage (P < 0.0001), pN+ (P = 0.0004), LVI (P < 0.0001) and female gender (P = 0.021) were significantly associated with a reduced CSS. Multivariate analysis identified a higher pT stage (P = 0.017) and LVI (P = 0.008) as independent predictors for reduced CSS. Independent predictors for reduced OS were a higher pT stage (P = 0.0007) and LVI (P = 0.0021), while overexpression of VEGF-D was associated with better OS (P < 0.0001).

CONCLUSIONS

The mRNA expression of the investigated markers showed associations with common histopathological parameters. Increased expression of VEGF-D is independently associated with better overall survival.

LNMAT1 promotes lymphatic metastasis of bladder cancer via CCL2 dependent macrophage recruitment

Tumor-associated macrophages (TAMs) are the most abundant inflammatory infiltrates in the tumor microenvironment and contribute to lymph node (LN) metastasis. However, the precise mechanisms of TAMs-induced LN metastasis remain largely unknown. Herein, we identify a long noncoding RNA, termed Lymph Node Metastasis Associated Transcript 1 (LNMAT1), which is upregulated in LN-positive bladder cancer and associated with LN metastasis and prognosis. Through gain and loss of function approaches, we find that LNMAT1 promotes bladder cancer-associated lymphangiogenesis and lymphatic metastasis. Mechanistically, LNMAT1 epigenetically activates CCL2 expression by recruiting hnRNPL to CCL2 promoter, which leads to increased H3K4 tri-methylation that ensures hnRNPL binding and enhances transcription. Furthermore, LNMAT1-induced upregulation of CCL2 recruits macrophages into the tumor, which promotes lymphatic metastasis via VEGF-C excretion. These findings provide a plausible mechanism for LNMAT1-modulated tumor microenvironment in lymphatic metastasis and suggest that LNMAT1 may represent a potential therapeutic target for clinical intervention in LN-metastatic bladder cancer.

Mapping of the three-dimensional lymphatic microvasculature in bladder tumours using light-sheet microscopy

BACKGROUND

Cancers are heterogeneous and contain various types of irregular structures that can go undetected when examining them with standard two-dimensional microscopes. Studies of intricate networks of vasculature systems, e.g., the tumour lymphatic microvessels, benefit largely from three-dimensional imaging data analysis.

METHODS

The new DIPCO (Diagnosing Immunolabeled Paraffin-Embedded Cleared Organs) imaging platform uses three-dimensional light-sheet microscopy and whole-mount immunolabelling of cleared samples to study proteins and micro-anatomies deep inside of tumours.

RESULTS

Here, we uncovered the whole three-dimensional lymphatic microvasculature of formalin-fixed paraffin-embedded (FFPE) tumours from a cohort of 30 patients with bladder cancer. Our results revealed more heterogeneous spatial deviations in more advanced bladder tumours. We also showed that three-dimensional imaging could determine tumour stage and identify vascular or lymphatic system invasion with higher accuracy than standard two-dimensional histological diagnostic methods. There was no association between sample storage times and outcomes, demonstrating that the DIPCO pipeline could be successfully applied on old FFPE samples.

CONCLUSIONS

Studying tumour samples with three-dimensional imaging could help us understand the pathological nature of cancers and provide essential information that might improve the accuracy of cancer staging.

Long noncoding RNA BLACAT2 promotes bladder cancer-associated lymphangiogenesis and lymphatic metastasis

The prognosis for bladder cancer patients with lymph node (LN) metastasis is dismal and only minimally improved by current treatment modalities. Elucidation of the molecular mechanisms that underlie LN metastasis may provide clinical therapeutic strategies for LN-metastatic bladder cancer. Here, we report that a long noncoding RNA LINC00958, which we have termed bladder cancer-associated transcript 2 (BLACAT2), was markedly upregulated in LN-metastatic bladder cancer and correlated with LN metastasis. Overexpression of BLACAT2 promoted bladder cancer-associated lymphangiogenesis and lymphatic metastasis in both cultured bladder cancer cell lines and mouse models. Furthermore, we demonstrate that BLACAT2 epigenetically upregulated VEGF-C expression by directly associating with WDR5, a core subunit of human H3K4 methyltransferase complexes. Importantly, administration of an anti-VEGF-C antibody inhibited LN metastasis in BLACAT2-overexpressing bladder cancer. Taken together, these findings uncover a molecular mechanism in the lymphatic metastasis of bladder cancer and indicate that BLACAT2 may represent a target for clinical intervention in LN-metastatic bladder cancer.

Implication of vascular endothelial growth factor A and C in revealing diagnostic lymphangiogenic markers in node-positive bladder cancer

Several lymphangiogenic factors, such as vascular endothelial growth factors (VEGFs), have been found to drive the development of lymphatic metastasis in bladder cancer (BCa).

Here, we have analyzed the gene expression of lymphangiogenic factors in tissue specimens from 12 non-muscle invasive bladder cancers (NMIBC) and 11 muscle invasive bladder cancers (MIBC), considering tumor and tumor-adjacent normal bladder areas obtained from the same organs. We then compared the results observed in patients with those obtained after treating human primary bladder microvascular endothelial cells (MEC) with either direct stimulation with VEGF-A or VEGF-C or by co-culturing (trans-well assay) MEC with bladder cancer cell lines varying in VEGF-A and VEGF-C production based on tumor grade.

The genes of three markers of lymphatic endothelial commitment and development (PDPN, LYVE-1 and SLP-76) were significantly overexpressed in tissues of MIBC patients showing positive lymphovascular invasion (LVI+), lymph node metastasis (Ln+) and tumor progression. Their expression was also significantly enhanced either after direct stimulation of MEC by VEGF-A and VEGF-C or in the trans-well assay with each bladder cancer cell line.

SLP-76 showed the highest gene expression. Both VEGF-A and VEGF-C also enhanced the expression of SLP-76 protein in MEC. However, a correlation between increase of SLP-76 gene expression and the ability of MEC to migrate could only be seen after induction by VEGF-C.

The significant expression of SLP-76 in LVI+/Ln+ progressive MIBC and its overexpression in MEC after VEGF-A and VEGF-C stimulation suggest the need to develop this regulator of developmental lymphangiogenesis as a diagnostic tool in BCa.

Angiogenesis in Schistosoma haematobium-associated urinary bladder cancer

Schistosoma haematobium, a parasitic flatworm that infects more than 100 million people, mostly in the developing world, is the causative agent of urogenital schistosomiasis, and is associated with a high incidence of squamous cell carcinoma (SCC) of the bladder. During infection, eggs are deposited in the bladder causing an intense inflammatory reaction. Angiogenesis is defined as the formation of new blood vessels from preexisting ones and is recognized as a key event in cell proliferation and carcinogenesis and spread of malignant lesions. A growing amount of evidence points to angiogenesis playing a key role in schistosomiasis-associated bladder cancer. Thus, identifying biomarkers of this process plays an important role in the study of cancer. Here, we review recent findings on the role of angiogenesis in bladder cancer and the growth factors that induce and assist in their development, particularly SCC of the bladder associated to urogenital schistosomiasis.

CCL21/CCR7 interaction promotes cellular migration and invasion via modulation of the MEK/ERK1/2 signaling pathway and correlates with lymphatic metastatic spread and poor prognosis in urinary bladder cancer

Lymph node metastasis in patients with urinary bladder cancer (UBC) is always associated with poor prognosis and is the determinant for tumor staging and the development of treatment regimens; however, its underlying mechanisms remain to be studied. Immunohistochemical staining of tumor sections from 62 UBC patients was performed using CCR7, D2-40 and CD34 antibodies. We showed that increased CCR7 expression was significantly associated with positive lymph node status (P=0.008), pT3-T4 tumor stage (P=0.015), tumor grade (P=0.010) and worse overall survival (OS, P<0.001) and that both CCR7 expression and lymph node metastasis were independent prognostic factors for OS (P=0.031 and P=0.001, respectively) based on multivariate analysis. We found that there was a significant association between MLVD and lymph node status (P=0.006), but this relation was not observed for MVD. Furthermore, we showed that increased CCR7 expression correlated significantly with higher MLVD (P=0.014) and MVD (P=0.002). Wound-healing and Matrigel Transwell assays indicated that activation of CCR7 with CCL21 significantly enhanced the invasion and migration abilities of UM-UC-3 cells, and this enhanced effect was significantly abrogated by CCR7 knockdown using siRNA. Western blot analysis revealed that the phospho-ERK1/2 level was markedly increased when UM-UC-3 cells were treated with CCL21 and significantly decreased when the CCR7 gene was silenced. MEK/ERK1/2 inhibition with PD98059 significantly suppressed the migration and invasion abilities of UM-UC-3 cells and also significantly abrogated the effects of CCL21/CCR7 on cell migration and invasion. Based on these results, we conclude that activation of the CCL21/CCR7 chemoaxis promotes lymph node metastasis of UBC in at least two ways. Firstly, although CCR7 is a promoting factor that induces both lymphangiogenesis and angiogenesis, it may promote lymph node metastasis through its lymphangiogenic effect rather than through its angiogenic effect. Secondly, the CCL21/CCR7 chemoaxis promotes the migration and invasion of UBC cells via the MEK/ERK1/2 signaling pathway rather than the PI3K/AKT pathway.

Tumor lymphangiogenesis and new drug development

Traditionally, tumor-associated lymphatic vessels have been regarded as passive by-standers, serving simply as a drainage system for interstitial fluid generated within the tumor. However, with growing evidence that tumors actively induce lymphangiogenesis, and that the number of lymphatic vessels closely correlates with metastasis and clinical outcome in various types of cancer, this picture has changed dramatically in recent years. Tumor-associated lymphatic vessels have now emerged as a valid therapeutic target to control metastatic disease, and the first specific anti-lymphangiogenic drugs have recently entered clinical testing. Furthermore, we are just beginning to understand the whole functional spectrum of tumor-associated lymphatic vessels, which not only concerns transport of fluid and metastatic cells, but also includes the regulation of cancer stemness and specific inhibition of immune responses, opening new venues for therapeutic applications. Therefore, we predict that specific targeting of lymphatic vessels and their function will become an important tool for future cancer treatment.

Prognostic Significance of Lymphatic Vessel Density Detected by D2-40 and Its Relation to Claudin-4 Expression in Prostatic Adenocarcinoma

Background Lymphovascular invasion is an important pathway of metastatic spread and regional lymph node metastasis is the major prognostic factor in prostatic adenocarcinoma. D2-40 is used to identify the lymphatic vessels and to assess the lymphatic vessel density (LVD). Expression of claudin-4 may be related to invasion and progression of carcinoma cells in several primary tumors. Aim To evaluate intra- and peritumoral LVD through immunohistochemical expression of D2-40 in relation to claudin-4 expression and clinicopathological parameters in prostatic adenocarcinoma. Materials and Methods Immunohistochemical staining procedure was performed on 53 paraffin-embedded blocks of radical prostatectomy specimens for prostatic adenocarcinoma using anti D2-40 and claudin-4 antibodies. Sections were evaluated for mean LVD in intratumoral and peritumoral tissues assessed by D2-40 expression. Results LVD in intratumoral tissues was significantly lower compared with peritumoral areas (P = .0001). Peritumoral mean LVD was significantly higher in cases with lymphovascular invasion (P = .041) and in cases with positive lymph node metastasis (P = .003) than intratumoral mean LVD. High claudin-4 expression was significantly correlated with high tumor grade (P = .0001), lymphovascular invasion (P = .006), and positive lymph node metastasis (P = .004). High claudin-4 expression was significantly associated with increased mean LVD in peritumoral tissues. Conclusion Increased peritumoral mean LVD in prostatic adenocarcinoma is associated with lymphovascular invasion and positive lymph node metastasis. High claudin-4 expression is associated with high tumor grade, lymphocascular invasion, positive lymph node metastasis, and high mean peritumoral LVD suggesting that D2-40 and claudin-4 may represent different mechanisms of lymphatic vessel invasion with both biomarkers is related to poor prognosis.

Biomarkers in bladder cancer: translational and clinical implications

Bladder cancer is associated with high recurrence and mortality rates. These tumors show vast heterogeneity reflected by diverse morphologic manifestations and various molecular alterations associated with these disease phenotypes. Biomarkers that prospectively evaluate disease aggressiveness, progression risk, probability of recurrence and overall prognosis would improve patient care. Integration of molecular markers with conventional pathologic staging of bladder cancers may refine clinical decision making for the selection of adjuvant and salvage therapy. In the past decade, numerous bladder cancer biomarkers have been identified, including various tumor suppressor genes, oncogenes, growth factors, growth factor receptors, hormone receptors, proliferation and apoptosis markers, cell adhesion molecules, stromal factors, and oncoproteins. Recognition of two distinct pathways for urothelial carcinogenesis represents a major advance in the understanding and management of this disease. Nomograms for combining results from multiple biomarkers have been proposed to increase the accuracy of clinical predictions. The scope of this review is to summarize the major biomarker findings that may have translational and clinical implications.

[Invasion patterns and metastasis of urothelial carcinoma. A challenge for translational research]

Local invasion of cancer cells occurs early during the progression of urothelial carcinoma. Micrometastatic disease and the presence of nodal metastases are major causes of cancer-specific mortality following radical surgery. Only surrogate markers for aggressive and micrometastatic disease have been identified. The metastatic cascade is complex, including multiple steps from initial invasion to colonization and proliferation at distant sites. The initial mechanisms of cancer cell dissemination in urothelial carcinoma are poorly understood. Various proteases, chemokines and growth factors are involved in this process and alterations of the lymphatic system may promote systemic spread. There is a high demand for therapeutic targeting of the metastatic process. Functional preclinical studies in representative models are therefore required to better elucidate the multiple steps of progression. We review the current knowledge on factors associated with metastasis in urothelial carcinoma. Preclinical approaches to identify key player molecules for invasion and to develop new therapeutic strategies are discussed.

Assessing the invasive potential of bladder cancer: development and validation of a new preclinical assay

PURPOSE

We developed and validated an electrophysiological method for standardized preclinical assessment of the invasive potential of urothelial carcinoma of the bladder.

MATERIALS AND METHODS

Human UMUC-3, RT-112, HT-1197 and T24/83 bladder urothelial carcinoma cells, and UROtsa benign urothelial cells were co-cultivated with high resistance MDCK-C7 cells seeded below a 0.4 μm pore membrane of an insert to avoid physical contact and cellular migration. Transepithelial electrical resistance in Ω cm(2) across the MDCK-C7 monolayer was measured longitudinally. Invasive potential coefficients were calculated based on the secretion of proteolytic factors by invading cells.

RESULTS

Consistent transepithelial electrical resistance breakdown patterns were reproduced in 14 or more independent samples of each cell line. Coefficients of invasive potential were significantly higher in bladder urothelial carcinoma than UROtsa cells, including a mean ± SD of 1.5 ± 0.32 vs 9.9 ± 4.97 in UMUC-3, 12.5 ± 6.61 in T24/83, 20.5 ± 4.24 in RT-112 and 21.0 ± 5.15 in HT-1197 cells (p <0.001). No correlation was found between the secretion patterns of matrix metalloproteinase-1, 2 and 9, and invasive potential. Stimulation of UROtsa cells with recombinant human epidermal growth factor up-regulated matrix metalloproteinase-9 secretion and significantly increased invasive potential a mean of 1.3 ± 0.22 vs 14.6 ± 3.28 after stimulation with 10 ng/ml epidermal growth factor (p <0.001).

CONCLUSIONS

We developed a highly sensitive translational tool to study the initial process of metastatic spread of urothelial carcinoma of the bladder. The presented electrophysiological invasion assay enables reliable quantification of the invasive potential of bladder urothelial carcinoma cells before physical transmigration. It can be used to identify key molecules for bladder urothelial carcinoma invasion and develop new therapeutic strategies.

Clinical significance of lymph vessel density in T3 colorectal carcinoma

PURPOSE

The purpose of the present study is to characterise the lymphatic vessel density (LVD) in the T3 colorectal carcinoma and to correlate it with N status, grading and presence of tumour budding.

METHODS

A total of 56 cases of T3 colorectal carcinoma were retrieved from the pathology's archive of Klinikum Augsburg. All slides were stained immunohistochemically with D2-40 (lymphatic endothelium) and with pancytokeratin to assess the tumour budding. Tumour budding and lymph vessel density were investigated independently by BM and CC. The highest density of lymphatic vessels was counted both in tumour centre (ILVD) and at the periphery of the tumour (PLVD) within an area of 0.24 mm(2).

RESULTS

Due to the strong intra-observer (BM and CC) difference in ILVD and PLVD, all cases were re-evaluated establishing a consensus that has been used for the further analyses. There was a significant difference between PLVD and ILVD (12 ± 4 versus 6 ± 3; P < 0.001). Moreover, we found a non-significant trend towards high PLVD in the cases with nodal metastasis versus the negative one, 13 ± 5/hpf versus 11 ± 4 (P = 0.072). There was no association between tumour budding and ILVD and PLVD (P = 0.249 and 0.38).

CONCLUSION

Colorectal carcinoma induces lymphangiogenesis. A higher PLVD could increase the capability of cancer cell to invade the lymphatic system. However, the obvious difficulties in immunohistochemical evaluation and the rather small differences between nodal positive and negative cases in T3 colorectal cancer seem to limit the clinical value of LVD evaluation.

Lymph vessel density in seminomatous testicular cancer assessed with the specific lymphatic endothelium cell markers D2-40 and LYVE-1: correlation with pathologic parameters and clinical outcome

OBJECTIVES

To evaluate the role of lymph vessel density (LVD) and lymphangiogenesis in seminomatous testicular cancer (STC) by using the lymphatic endothelial cell (LEC) markers LYVE-1 and D2-40.

METHODS AND MATERIALS

Paraffin embedded tumor specimens from 40 patients with STC were stained by specific D2-40 and Lyve-1 antibodies. LVD was measured in different representative and standardized areas. Fluorescence double immunostaining for Lyve-1 and Ki-67 was performed and results were correlated with clinicopathologic data. The median follow-up period was 55 (range 10-135) months.

RESULTS

Mean intratumoral LVD (D2-40: 1.30 ± 1.99; Lyve-1: 1.82 ± 2.34) was significantly lower than peritumoral LVD (D2-40: 4.94 ± 2.58; Lyve-1: 4.62 ± 2.73) and LVD in nontumoral areas (D2-40: 4.81 ± 3.79; Lyve-1: 4.22 ± 3.19). There was no significant difference between LVD measures when using D2-40 or LYVE-1. Detection rates of lymphatic vascular invasion (LVI) were significantly higher than in conventional HE-stained sections (77.5% vs. 52.5%). No proliferating lymphatic vessels were found.

CONCLUSIONS

We found that LVD is decreased within tumor areas of STC. Despite a higher peritumoral LVD, no signs of proliferating endothelial cells were observed, suggesting a lack of lymphangiogenesis in STC. Detection of LVI can be optimized by specific D2-40 or LYVE-1 staining.

Soluble vascular endothelial growth factor receptor-3 suppresses lymphangiogenesis and lymphatic metastasis in bladder cancer

Background

Most bladder cancer patients experience lymphatic metastasis in the course of disease progression, yet the relationship between lymphangiogenesis and lymphatic metastasis is not well known. The aim of this study is to elucidate underlying mechanisms of how expanded lymphatic vessels and tumor microenvironment interacts each other and to find effective therapeutic options to inhibit lymphatic metastasis.

Results

The orthotopic urinary bladder cancer (OUBC) model was generated by intravesical injection of MBT-2 cell lines. We investigated the angiogenesis, lymphangiogenesis, and CD11b⁺/CD68⁺ tumor-associated macrophages (TAM) by using immunofluorescence staining. OUBC displayed a profound lymphangiogenesis and massive infiltration of TAM in primary tumor and lymphatic metastasis in lymph nodes. TAM flocked near lymphatic vessels and express higher levels of VEGF-C/D than CD11b^- cells. Because VEGFR-3 was highly expressed in lymphatic vascular endothelial cells, TAM could assist lymphangiogenesis by paracrine manner in bladder tumor. VEGFR-3 expressing adenovirus was administered to block VEGF-C/D signaling pathway and clodronate liposome was used to deplete TAM. The blockade of VEGF-C/D with soluble VEGF receptor-3 markedly inhibited lymphangiogenesis and lymphatic metastasis in OUBC. In addition, the depletion of TAM with clodronate liposome exerted similar effects on OUBC.

Conclusion

VEGF-C/D are the main factors of lymphangiogenesis and lymphatic metastasis in bladder cancer. Moreover, TAM plays an important role in these processes by producing VEGF-C/D. The inhibition of lymphangiogenesis could provide another therapeutic target to inhibit lymphatic metastasis and recurrence in patients with invasive bladder cancer.

Neuropilin-VEGF signaling pathway acts as a key modulator of vascular, lymphatic, and inflammatory cell responses of the bladder to intravesical BCG treatment

Recent findings indicate that VEGF receptors and coreceptors (neuropilins; NRP) are expressed on nonendothelial cells in human bladder urothelium, in one human bladder cancer cell line (J82), and in the mouse bladder urothelium. In addition, VEGFR1, VEGFR2, NRP1, and NRP2 expressions were upregulated in animal models of chronic bladder inflammation induced by four weekly instillations of protease-activated receptors (PAR)-activating peptides or bacillus Calmette-Guérin (BCG) into the mouse bladder. Here, we used four weekly instillations of BCG as a model for chronic bladder inflammation to further investigate whether VEGF receptors and NRPs play a role in the migration of inflammatory cells and inflammation-induced lymphangiogenesis and angiogenesis. For this purpose, we used neutralizing antibodies that were engineered to specifically block the binding of VEGF to NRP (anti-NRP1(B)) and the binding of semaphorins to NRP (anti-NRP1(A)). C57BL/6 mice received intraperitoneal injections of PBS, anti-NRP1(A)- or anti-NRP1(B)-neutralizing antibodies and then were challenged chronically with intravesical PBS or BCG. At the end of chronic challenge period, a fluorescent internalizable tracer, scVEGF/Cy5.5, was administered to all mice and near-infrared fluorescence images were obtained in vivo and in real time. BCG increased the overall accumulation of scVEGF/Cy5.5 in the urinary bladder urothelium and inflammatory cells. In addition, BCG increased the density of blood and lymphatic vessels concomitantly with an upregulation of NRP2 expression in lymphatic vessels. Treatment of the mice with NRP1-neutralizing antibodies dramatically reduced scVEGF/Cy5.5 uptake, polymorphonuclear (myeloperoxidase-positive cells) and dendritic cell (CD11c-positive cells) infiltration, and decreased the overall density of BCG-induced blood and lymphatic vessels. These results implicate NRPs as critical in vivo regulators of the vascular and inflammatory responses to the intravesical administration of BCG.

Lymphangiogenesis: A new player in cancer progression

Lymph node metastasis is the hallmark of colon cancer progression, and is considered one of the most important prognostic factors. Recently, there has been growing evidence that tumor lymphangiogenesis (formation of new lymphatic vessels) plays an important role in this process. Here, we review the latest findings of the role of lymphangiogenesis in colorectal cancer progression, and discuss its clinical application as a biomarker and target for new therapy. Understanding the molecular pathways that regulate lymphangiogenesis is mandatory to pave the way for the development of new therapies for cancer. In the future, tailored treatments consisting of combinations of chemotherapy, other targeted therapies, and anti-lymphangiogenesis agents will hopefully improve patient outcomes. This progression to the clinic must be guided by new avenues of research, such as the identification of biomarkers that predict response to treatment.

The aggressiveness of urothelial carcinoma depends to a large extent on lymphovascular invasion--the prognostic contribution of related molecular markers

AIMS

Bladder cancer is the second most common malignancy of the urogenital region. The majority of bladder cancer deaths occur as a consequence of metastatic disease. Blood vessel density (BVD), a surrogate marker for angiogenesis, has been shown to be predictive of progression and poor prognosis, as well as lymphatic vessel density (LVD). The aim of this study was to evaluate, in human urothelial bladder cancer (UBC), the clinical and prognostic significance of angiogenesis, lymphangiogenesis and lymphovascular invasion, assessed with the use of specific immunohistochemical markers.

METHODS AND RESULTS

Immunohistochemistry for CD31 (a blood vessel endothelial cell marker), D2-40 (a lymphatic vessel endothelial cell marker), vascular endothelial growth factor (VEGF)-C and VEGF-receptor 3 antibodies was performed in 83 patients with urothelial carcinoma who underwent radical cystectomy. The classic histopathological characteristics, associated with lymphovascular invasion and loco-regional dissemination, had a negative influence on 5-year overall survival (OS) rates. BVD and LVD were correlated with advanced and poorly differentiated UBC with lymphovascular invasion. Blood vessel invasion (BVI) by malignant emboli assessed by CD31 staining, and lymphatic vessel invasion (LVI) by isolated malignant cells assessed by D2-40 staining significantly affected OS. VEGF-C overexpression was correlated with both BVI and LVI by single malignant cells assessed by CD31 and D2-40, respectively. BVI by malignant emboli assessed by CD31 staining remained as an independent prognostic factor.

CONCLUSIONS

Patients with UBC with embolic BVI assessed by CD31 and LVI by isolated malignant cells assessed by D2-40 have a worse prognosis and may benefit from adjuvant therapies.

Molecular biomarkers for urothelial carcinoma of the bladder: challenges in clinical use

Conventional clinical and pathological parameters are limited in their capacity to detect patients with urothelial carcinoma of the bladder (UCB) who are at high risk for recurrence or mortality. The assessment of molecular biomarkers in surgical UCB specimens offers additional information on the biology of the disease, and might improve the prediction of oncologic end points. A wide range of candidate biomarkers, including key cell-cycle regulators, apoptotic markers and specific growth factors, have been reported to be of prognostic value. To date, however, no molecular biomarker for UCB has been introduced into clinical practice, mainly owing to insufficient validation and the absence of prospective studies. Knowledge about the value of molecular biomarkers in predicting the response to adjuvant or neoadjuvant therapies is also lacking. Prospective trials need to be initiated in high-risk patients selected on the basis of the expression patterns of molecular biomarkers that have already passed the initial steps towards clinical utility.

Mechanisms of lymphatic metastasis in human colorectal adenocarcinoma

The invasion of lymphatic vessels by colorectal cancer (CRC) and its subsequent spread to draining lymph nodes is a key determinant of prognosis in this common and frequently fatal malignancy. Although tumoural lymphangiogenesis is assumed to contribute to this process, review of the current literature fails to support any notion of a simple correlation between lymphatic vessel density and CRC metastasis. Furthermore, attempts to correlate the expression of various lymphangiogenic growth factors, most notably VEGF-C and VEGF-D, with the lymphatic metastasis of CRC have provided contradictory results. Recent evidence from animal and human models of tumour metastasis suggests that complex functional and biochemical interactions between the microvasculature of tumours and other cell types within the tumour microenvironment may play a pivotal role in the behaviour of commonly metastasizing tumours. Indeed, previous insights into tumoural blood vessels have provided candidate markers of tumoural angiogenesis that are currently the subject of intense investigation as future therapeutic targets. In this review article we survey the current evidence relating lymphangiogenesis and lymphangiogenic growth factor production to metastasis by CRC, and attempt to provide some insight into the apparent discrepancies within the literature. In particular, we also discuss some new and provocative insights into the properties of tumoural lymphatics suggesting that they have specific expression profiles distinct from those of normal lymphatic vessels and that appear to promote metastasis. These findings raise the exciting prospect of future biomarkers of lymphatic metastasis and identify potential targets for new generation anti-tumour therapies.

Lymphangiogenesis occurs in upper tract urothelial carcinoma and correlates with lymphatic tumour dissemination and poor prognosis

OBJECTIVE

To describe the lymphatic vessel density and to determine the functional and prognostic significance of tumoral lymphatic vessels in upper tract urothelial carcinoma (UTUC).

PATIENTS AND METHODS

The study included 65 patients who had a radical nephroureterectomy (RNU) for UTUC between 1997 and 2004. All pathological slides were re-evaluated by one reference pathologist and clinical data were reviewed. Lymphatic endothelial cells (LECs) were stained immunohistochemically using D2-40. The lymphatic vessel density (LVD) was described in representative intratumoral (ITLVD), peritumoral (PTLVD) and non-tumoral (NTLVD) areas. Random samples were selected for double-immunostaining with D2-40 and CD-34 (to distinguish blood and lymphatic vessels) and the proliferation marker Ki-67 to detect lymphangiogenesis. The primary outcome measures were disease-specific survival (DSS) and disease recurrence (urothelial and/or distant).

RESULTS

The median (interquartile range) PTLVD was 4.0 (3.0-6.3), and significantly higher than that for ITLVD, of 0.3 (0-1.7) (P < 0.001), and NTLVD, of 3 (2.0-3.7) (P < 0.001). Both a higher ITLVD and PTLVD, the presence of lymphovascular invasion (LVI) (each P < 0.001) and a high tumour grade (P = 0.004) were associated with reduced DSS on univariate analysis. A higher PTLVD (P = 0.028) and the presence of LVI (P = 0.020) independently predicted reduced DSS on multivariate analysis. IT and PT lymphatic vessels showed proliferating LECs in all analysed samples.

CONCLUSION

Lymphangiogenesis is present in UTUC, as shown by a significantly increased PTLVD and proliferating LECs. Our findings suggest functional relevance of PT lymphatic vessels during lymphatic tumour spread. PTLVD is a potential novel prognostic factor for DSS in UTUC, and further prospective studies will be needed to determine the effect of its routine evaluation on clinical outcomes of this malignancy.

Topical chemotherapy in human urothelial carcinoma explants: a novel translational tool for preclinical evaluation of experimental intravesical therapies

BACKGROUND

Urothelial carcinoma (UC) is associated with a high local recurrence rate despite intravesical therapy. There is a lack of representative preclinical models for standardized testing of novel experimental therapies.

OBJECTIVE

To develop an ex vivo model for human UC and to evaluate its ability to generate reproducible and reliable results when testing cytotoxic agents.

DESIGN, SETTING, AND PARTICIPANTS

Normal human urothelium (NHU) and bladder UC explants were collected from patients treated at our institution. A total of 195 surgical explants were cultured on a gelatine matrix. Tissue viability was regularly assessed using nicotinamide adenine dinucleotide (NADH) diaphorase enzymehistochemistry. Topical paclitaxel (PTX) or mitomycin C (MMC) chemotherapy was performed in a subset of 45 UC specimens.

INTERVENTION

All patients underwent radical cystectomy (RC) or primary transurethral resection (TUR) of a bladder UC.

MEASUREMENTS

Triple immunofluorescence (pan-cytokeratin [pan-CK]; 4',6-diamidin-2'-phenylindol-dihydrochloride [DAPI]; terminal deoxynucleotidyl transferase biotin-dUTP nick-end labelling [TUNEL]) and caspase-3 staining of paraffin sections was performed. Proliferation rates were assessed using Ki-67 labelling indices. Apoptosis (percent) was quantified in representative tissue areas to characterize culture stability and to assess antineoplastic effects.

RESULTS AND LIMITATIONS

No signs of necrosis and no significant changes in apoptosis were observed during the first 12 d of culture. Of all explants, 88.5% were vital after 20 d. In a highly reproducible fashion, topical chemotherapy resulted in significantly increased apoptosis (37.4% [19.0-75.0%] for PTX and 36.2% [18.8-46.7%] for MMC) compared with controls (7.5% [3.0-26.8%]; p<0.001]). No statistically significant difference was observed regarding the effects of the two chemotherapeutic agents (p=0.119).

CONCLUSIONS

The presented human ex vivo model takes UC heterogeneity into account and serves as a valuable translational tool. It offers an attractive alternative to preclinical cell line experiments or animal models and may even be used for prospective toxicity and drug efficacy tests in individual patients.

Lymphatic vessel density and function in experimental bladder cancer

BACKGROUND

The lymphatics form a second circulatory system that drains the extracellular fluid and proteins from the tumor microenvironment, and provides an exclusive environment in which immune cells interact and respond to foreign antigen. Both cancer and inflammation are known to induce lymphangiogenesis. However, little is known about bladder lymphatic vessels and their involvement in cancer formation and progression.

METHODS

A double transgenic mouse model was generated by crossing a bladder cancer-induced transgenic, in which SV40 large T antigen was under the control of uroplakin II promoter, with another transgenic mouse harboring a lacZ reporter gene under the control of an NF-kappaB-responsive promoter (kappaB-lacZ) exhibiting constitutive activity of beta-galactosidase in lymphatic endothelial cells. In this new mouse model (SV40-lacZ), we examined the lymphatic vessel density (LVD) and function (LVF) during bladder cancer progression. LVD was performed in bladder whole mounts and cross-sections by fluorescent immunohistochemistry (IHC) using LYVE-1 antibody. LVF was assessed by real-time in vivo imaging techniques using a contrast agent (biotin-BSA-Gd-DTPA-Cy5.5; Gd-Cy5.5) suitable for both magnetic resonance imaging (MRI) and near infrared fluorescence (NIRF). In addition, IHC of Cy5.5 was used for time-course analysis of co-localization of Gd-Cy5.5 with LYVE-1-positive lymphatics and CD31-positive blood vessels.

RESULTS

SV40-lacZ mice develop bladder cancer and permitted visualization of lymphatics. A significant increase in LVD was found concomitantly with bladder cancer progression. Double labeling of the bladder cross-sections with LYVE-1 and Ki-67 antibodies indicated cancer-induced lymphangiogenesis. MRI detected mouse bladder cancer, as early as 4 months, and permitted to follow tumor sizes during cancer progression. Using Gd-Cy5.5 as a contrast agent for MRI-guided lymphangiography, we determined a possible reduction of lymphatic flow within the tumoral area. In addition, NIRF studies of Gd-Cy5.5 confirmed its temporal distribution between CD31-positive blood vessels and LYVE-1 positive lymphatic vessels.

CONCLUSION

SV40-lacZ mice permit the visualization of lymphatics during bladder cancer progression. Gd-Cy5.5, as a double contrast agent for NIRF and MRI, permits to quantify delivery, transport rates, and volumes of macromolecular fluid flow through the interstitial-lymphatic continuum. Our results open the path for the study of lymphatic activity in vivo and in real time, and support the role of lymphangiogenesis during bladder cancer progression.