Exosomes derived from the urine of patients with bladder cancer contains bioactive molecules such as EDIL-3. Identifying these components and their associated oncogenic pathways could lead to novel therapeutic targets and treatment strategies.
Bacillus Calmette-Guérin (BCG), a vaccine against tuberculosis(TB), has been used and proven to be one of the most effective treatments for non-muscle invasive bladder cancer (BCa). However, the mechanisms of BCG action have not been completely understood, thereby limiting the improvement of BCG therapy. Vitamin D deficiency has been associated with a high risk of TB infection, and the beneficial effect of UV exposure in TB patients was proven to be mediated via activation of vitamin D signals of innate immune cells. Thus, vitamin D signals might be involved in mediating BCG immunotherapy. To test this hypothesis, we examined the impact of 1alpha, 25-dihydroxyvitamin D3 (1,25-VD) on BCG-induced response in BCa cells and macrophage cells. Our data revealed that 1,25-VD promotes BCG-induced interleukin 8 (IL-8) secretion by BCa cells, consequently inducing the migration of macrophage, THP-1. This THP-1 cell migration promoted by 1,25-VD can be blocked by IL-8 neutralized antibody. Furthermore, 1,25-VD increased BCG-induced expression of macrophage markers in THP-1 cell, and enhanced the BCG-induced THP-1 cytotoxicity against low-grade BCa cells. Importantly, a pre-clinical trial using the N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced BCa mouse model revealed that intravesical co-treatment of 1,25-VD with BCG can prolong mice survival. These data demonstrate a novel mechanism by which 1,25-VD promotes BCG-mediated anti-BCa pathways and provides a platform for improving BCG efficacy with combination of 1,25-VD.
Background
One of the most challenging tasks for bladder cancer diagnosis is to histologically differentiate two early stages, non-invasive Ta and superficially invasive T1, the latter of which is associated with a significantly higher risk of disease progression. Indeed, in a considerable number of cases, Ta and T1 tumors look very similar under microscope, making the distinction very difficult even for experienced pathologists. Thus, there is an urgent need for a favoring system based on machine learning (ML) to distinguish between the two stages of bladder cancer.
Methods
A total of 1177 images of bladder tumor tissues stained by hematoxylin and eosin were collected by pathologists at University of Rochester Medical Center, which included 460 non-invasive (stage Ta) and 717 invasive (stage T1) tumors. Automatic pipelines were developed to extract features for three invasive patterns characteristic to the T1 stage bladder cancer (i.e., desmoplastic reaction, retraction artifact, and abundant pinker cytoplasm), using imaging processing software ImageJ and CellProfiler. Features extracted from the images were analyzed by a suite of machine learning approaches.
Results
We extracted nearly 700 features from the Ta and T1 tumor images. Unsupervised clustering analysis failed to distinguish hematoxylin and eosin images of Ta vs. T1 tumors. With a reduced set of features, we successfully distinguished 1177 Ta or T1 images with an accuracy of 91–96% by six supervised learning methods. By contrast, convolutional neural network (CNN) models that automatically extract features from images produced an accuracy of 84%, indicating that feature extraction driven by domain knowledge outperforms CNN-based automatic feature extraction. Further analysis revealed that desmoplastic reaction was more important than the other two patterns, and the number and size of nuclei of tumor cells were the most predictive features.
Conclusions
We provide a ML-empowered, feature-centered, and interpretable diagnostic system to facilitate the accurate staging of Ta and T1 diseases, which has a potential to apply to other types of cancer.
Recent data suggest that patients with a basal/stem-like bladder cancer (BC) subtype tend to have metastatic disease, but this is unconfirmed. Here we report the identification of murine MB49 cell line sub-clones with stem-like characteristics in culture. Subcutaneous implantation of S2 and S4 MB49 sub-clones into immunocompetent mice resulted in lung metastases in 50% and 80% of mice respectively, whereas none of the mice implanted with the parental cells developed metastasis. Gene profiling of cells cultured from S2 and S4 primary and metastatic tumors revealed that a panel of genes with basal/stem-like/EMT properties is amplified during metastatic progression. Among them,
ITGB1
,
TWIST1
and
KRT6B
are consistently up-regulated in metastatic tumors of both MB49 sub-clones. To evaluate clinical relevance, we examined these genes in a human public dataset and found that
ITGB1
and
KRT6B
expression in BC patient tumor samples are positively correlated with tumor grade. Likewise, the expression levels of these three genes are correlated with worse clinical outcomes. This MB49 BC metastatic pre-clinical model provides a unique opportunity to validate and recapitulate results discovered in patient studies and to pursue future mechanistic therapeutic interventions for BC metastasis.
Small membrane-bound vesicles called exosomes are proving to be critical mediators of tumor progression. Here we show, for the first time, that exosomes isolated from the urine of patients with high-grade bladder cancer facilitate tumor progression and contain the matrix-associated glycoprotein EGF-like repeats and discoidin I-like domains (EDIL-3 aka Del1). EDIL-3 is a well-known tumor-associated angiogenic factor and increased expression of EDIL-3 has been shown in numerous tumors to correlate with poor prognosis. We demonstrate, that exosome-derived EDIL-3 is important for angiogenesis as well as urothelial and endothelial cell migration. Importantly, we show that recombinant (r)EDIL-3 is sufficient to promote migration of human urothelial carcinoma 5637 cells and blockade of either the epidermal growth factor receptor (EGFR) and/or the EGFR signal transduction propagating integrin beta 1 abrogated this effect. These data suggest a novel mechanism by which EDIL-3 may be involved in signal transduction pathways in cancer.
Citation Format: Carla Beckham, Christopher Silvers, Jayme Olsen, Peng-nien Yin, Chia-Hao Wu, Huei-ju Ting, Fred Hagen, Emelian Scosyrev, Edward Messing. Urothelial carcinoma exosomes contain Del1/EDIL-3 and facilitate bladder cancer progression. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr B05.
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