Prognostic value of vascular mimicry in patients with urothelial carcinoma of the bladder after radical cystectomy

Vascular mimicry and mosaic vessels in parathyroid tumours: a new diagnostic approach?

AIMS

Evaluation of 'alternative' vascularisation in human cancer is considered an important prognostic parameter; the 2022 WHO classification of parathyroid tumours despite progresses in clinical triaging of patients strongly emphasises new histopathological parameters to properly stratify these lesions. 'Alternative' and 'classic' vessels were here investigated for the first time in parathyroid tumours for their possible histopathological and clinical relevance during progression.

METHODS

Using a double CD31/PAS staining, microvessel density (MVD, 'classic' CD31+ vessels), mosaic vessel density (MoVD, 'alternative' CD31+/-vessels) and vessel mimicry density (VMD, 'alternative' CD31-/PAS+ vessels) were evaluated in 4 normal parathyroid glands (N), 50 Adenomas (A), 35 Atypical Tumours (AT) and 10 Carcinomas (K).

RESULTS

Compared with N, MVD significantly increased in A (p=0.012) and decreased in K (p=0.013) with vessel counts lower than in AT and A (p<0.001). MoVs and VMs, absent in normal tissue, were documented in non-benign parathyroid lesions (AT, K) (p<0.001), with MoVs and VMs most represented in AT and K, respectively (p<0.001), in peripheral growing areas. Vessel distribution was correlated to neoplastic progression (r=-0.541 MVD; r=+0.760 MoVD, r=+0.733 VMD), with MVD decrease in AT and K inversely related to MoVD and VMD increase (r=-0.503 and r=-0.456).

CONCLUSIONS

'Alternative' vessel identification in parathyroid tumours is crucial because it: (1) explains the paradox of non-angiogenic tumours, consisting in a new bloody non-endothelial vessel network and (2) helps pathologists to unmask worrisome lesions. Furthermore, detection of alternative vascular systems in human tumours might explain the limited success of antiangiogenic therapies and encourage new oncological studies.

N-myc downstream-regulated gene 1 can promote vasculogenic mimicry and angiogenesis in urothelial carcinoma

Urothelial carcinoma (UC) of the bladder is a common cause of cancer-related death worldwide. Vasculogenic mimicry (VM) is a process by which the malignant cells can generate vascular-like structures formed of periodic acid-Schiff (PAS) positive/CD31 negative extracellular matrix independent of angiogenesis and thus promotes tumor progression. N-myc downstream-regulated gene 1 (NDRG1) is a protein that can modulate tumor angiogenesis; however, its role in regulating tumor angiogenesis and VM formation has not been previously investigated in UC. This study aims to evaluate the role of intra-tumor microvessel density (MVD) (as a surrogate measure of angiogenesis), VM, and NDRG1 in UC and their correlation with different clinicopathologic features, then assess the correlation between them in UC. Sixty specimens of UC of the bladder were included. PAS-CD31 immunohistochemical double staining method was used to evaluate the intra-tumor MVD and VM. Immunohistochemical expression of NDRG1 was also examined. VM and NDRG1 expression were detected in 41.7% and 83.3% of UC specimens respectively. The mean of intra-tumor MVD, VM area, and NDRG1 was significantly higher in tumors with higher grade, lymphovascular invasion, and higher T stage. NDRG1 expression was positively correlated with MVD and VM. We can suggest that MVD, VM, and NDRG1 may serve as poor prognostic markers for UC. The positive correlation between NDRG1 and both MVD and VM may provide the first evidence that NDRG1 can induce tumor angiogenesis and VM in UC which may offer a novel pathway for further therapeutic strategies.

An Overview of Angiogenesis in Bladder Cancer

PURPOSE OF THE REVIEW

Angiogenesis plays a key role in bladder cancer (BC) pathogenesis. In the last two decades, an increasing number of publications depicting a multitude of novel angiogenic molecules and pathways have emerged. The growing complexity necessitates an evaluation of the breadth of current knowledge to highlight key findings and guide future research.

RECENT FINDINGS

Angiogenesis is a dynamic biologic process that is inherently difficult to assess. Clinical assessment of angiogenesis in BCs is advancing with the integration of image analysis systems and dynamic contrast-enhanced and magnetic resonance imaging (DCE-MRI). Tumour-associated macrophages (TAMs) significantly influence the angiogenic process, and further research is needed to assess their potential as therapeutic targets. A rapidly growing list of non-coding RNAs affect angiogenesis in BCs, partly through modulation of vascular endothelial growth factor (VEGF) activity. Vascular mimicry (VM) has been repeatedly associated with increased tumour aggressiveness in BCs. Standardised assays are needed for appropriate identification and quantification of VM channels. This article demonstrates the dynamic and complex nature of the angiogenic process and asserts the need for further studies to deepen our understanding.

TJP1 promotes vascular mimicry in bladder cancer by facilitating VEGFA expression and transcriptional activity through TWIST1

Tight junction protein 1 (TJP1) is a recently identified prominent regulator of bladder cancer (BLCA) angiogenesis and tumorigenesis. Vascular mimicry (VM) is a newly described tumor feature and is correlated with an increased risk of tumor metastasis. However, the relationship between TJP1 expression and VM in bladder cancer remains elusive. In the present study, we report a novel function for TJP1 in accommodating VM to promote tumor progression. We found that the elevated TJP1 expression was positively related to VM in patients and xenograft tumor models in bladder cancer. Enforced expression of TJP1 increased VM of BLCA cells in vitro and in vivo by elevating Vascular endothelial growth factor A (VEGFA) levels. Furthermore, VM induced by TJP1 overexpression was significantly blocked by the VEGFA and VEGFR inhibitors (Bevacizumab and Sunitinib). Mechanistically, TJP1 promoted VEGFA transcriptional and protein level in a TWIST1-dependent manner. Taken together, our study reveals that TJP1-regulated VEGFA overexpression may indicate a potential therapeutic target for clinical intervention in the early tumor neovascularization of bladder cancer.

Tight junction protein 1 promotes vasculature remodeling via regulating USP2/TWIST1 in bladder cancer

Bladder cancer (BLCA) is the most common malignant tumor of the urinary system and is characterized by high metastatic rates and poor prognosis. The expression of tight junction protein 1 (TJP1) is associated with bladder cancer invasion; however, the mechanism by which TJP1 affects vasculature remodeling remains unknown. In this study, we found that TJP1 expression correlated with tumor angiogenesis and poor overall survival in clinical samples. Furthermore, TJP1 overexpression promoted tumor angiogenesis in BLCA cells and stimulated recruitment of macrophages to tumors by upregulating CCL2 expression. Mechanistically, TJP1 interacted with TWIST1 and enhanced the transcriptional activity of CCL2. The impairment of tumor angiogenesis caused by knockdown of TJP1 was dramatically rescued by overexpression of TWIST1. Furthermore, TJP1 recruited USP2, which deubiquitinated TWIST1, thereby protecting TWIST1 from proteasome-mediated protein degradation. In conclusion, our results suggest that TJP1 controls angiogenesis in BLCA via TWIST1-dependent regulation of CCL2. We demonstrate that TJP1 functions as a scaffold for the interaction between USP2 and TWIST1 and this may provide potential therapeutic targets in bladder cancer.

Vasculogenic Mimicry Formation Predicts Tumor Progression in Oligodendroglioma

Vasculogenic mimicry (VM) has been identified as an important vasculogenic mechanism in malignant tumors, but little is known about its clinical meanings and mechanisms in oligodendroglioma. In this study, VM-positive cases were detected in 28 (20.6%) out of 136 oligodendroglioma samples, significantly associated with higher WHO grade, lower Karnofsky performance status (KPS) scores, and recurrent tumor (p < 0.001, p = 0.040, and p = 0.020 respectively). Patients with VM-positive oligodendroglioma had a shorter progress-free survival (PFS) compared with those with VM-negative tumor (p < 0.001), whereas no significant difference was detected in overall survival (OS) between these patients. High levels of phosphorylate serine/threonine kinases Ataxia-telangiectasia mutated (pATM) and phosphorylate Ataxia-telangiectasia and Rad3-Related (pATR) were detected in 31 (22.8%) and 34 (25.0%), respectively out of 136 oligodendroglioma samples. Higher expressions of pATM and pATR were both associated with a shorter PFS (p < 0.001 and p < 0.001). VM-positive oligodendroglioma specimens tended to exhibit higher pATM and pATR staining than VM-negative specimens (r_s = 0.435, p < 0.001 and r_s = 0.317, p < 0.001). Besides, Hypoxia-inducible factor-1α (HIF1α) expression was detected in 14(10.3%) samples, correlated with higher WHO grade and non-frontal lobe (p = 0.010 and p = 0.029). However, no obvious connection was detected between HIF1α expression and VM formation (p = 0.537). Finally, either univariate or multivariate analysis suggested that VM was an independent unfavorable predictor for oligodendroglioma patients (p < 0.001, HR = 7.928, 95%CI: 3.382-18.584, and p = 0.007, HR = 4.534, 95%CI: 1.504-13.675, respectively). VM is a potential prognosticator for tumor progression in oligodendroglioma patients. Phosphorylation of ATM and ATR linked to treatment-resistance may be associated with VM formation. The role of VM in tumor progression and the implication of pATM/pATR in VM formation may provide potential therapeutic targets for oligodendroglioma treatment.

Vasculogenic mimicry in bladder cancer and its association with the aberrant expression of ZEB1

The aim of the present study was to investigate the associations between vasculogenic mimicry (VM) and zinc finger E-box binding homeobox 1 (ZEB1) in bladder cancer. VM structure and ZEB1 expression were analyzed by cluster of differentiation 34/periodic acid Schiff (PAS) double staining and immunohistochemical staining in 135 specimens from patients with bladder cancer, and a further 12 specimens from normal bladder tissues. Three-dimensional (3-D) culture was used to detect VM formation in the bladder transitional cancer cell lines UM-UC-3 and J82, and the immortalized human bladder epithelium cell line SV-HUC-1 in vitro. ZEB1 expression in these cell lines was compared by reverse transcription-quantitative polymerase chain reaction and western blot assays. In addition, small interfering RNA was used to inhibit ZEB1 in UM-UC-3 and J82 cells, followed by 3-D culturing of treated cell lines. As a result, VM was observed in 31.1% of specimens from bladder cancer tissues, and cases with high ZEB1 expression accounted for 60.0% of patients with bladder cancer. In addition, ZEB1 expression was closely associated with VM (r=0.189; P<0.05), and also increased as the grade and stage of the tumor developed. In an in vitro assay, UM-UC-3 and J82 cells exhibited VM formation, however, SV-HUC-1 did not. Furthermore, VM-forming cancer cell lines UM-UC-3 and J82 exhibited higher ZEB1 expression. Notably, VM formation was inhibited following knockdown of ZEB1. In conclusion, ZEB1 may be associated with VM in bladder cancer and serve an important role in the process of VM formation. However, its detailed mechanism requires further study.