Normal and neoplastic urothelial stem cells: getting to the root of the problem

Intravesical Instillation of Hyaluronic Acid With Epidermal Growth Factor for Restoring Urothelial Denudation and Alleviating Oxidative Stress in Lipopolysaccharide-Induced Interstitial Cystitis of Rats

PURPOSE

To investigate the efficacy of an intravesical instillation of hyaluronic acid (HA) combined with epidermal growth factor (EGF) for the treatment of interstitial cystitis (IC) using a lipopolysaccharide (LPS)-induced IC animal model.

METHODS

A total of 24 female Sprague-Dawley rats were randomized to 4 groups: sham control, IC, HA, and treatment (HA/ EGF) groups. A polyethylene-50 tube was placed inside the bladder of each animal. IC was induced by twice-weekly instillations of LPS for 3 weeks, which resulted in chronic injury of the urothelium. Animals in the sham control group only received saline instillation. Treatment solutions of HA and HA/EGF were given on days 0, 7, and 14 after IC induction (400 μL of HA in a concentration of 0.4 mg/0.5 mL and 400 μL of NewEpi, a commercialized HA/EGF mixture containing 2 μg of EGF and 0.4 mg of sodium hyaluronate). Animals were sacrificed on day 21 for further examinations.

RESULTS

The HA/EGF group showed visible improvement in hematuria with a significant reduction of red blood cells in the urine compared to the HA group. Histological examination revealed that HA/EGF treatment reversed the abnormalities developed in IC, including infiltration of inflammatory cells, irregular re-epithelialization, and fibrotic tissue. Moreover, HA/ EGF significantly reduced the levels of proinflammation cytokines (tumor necrosis factor-α, interleukin [IL]-6, and IL-1β) and substantially lowered the elevated oxidative stress biomarker malondialdehyde, yet restored the levels of antioxidant enzymes glutathione peroxidase and superoxide dismutase, with superior results than HA treatment. Cystometry studies indicated that HA/EGF significantly prolonged intercontraction interval and increased micturition volume.

CONCLUSION

HA/EGF has been demonstrated as a more effective treatment for enhancing the urothelium lining and reducing inflammatory changes to alleviate clinical symptoms associated with IC in rats, compared to HA alone.

Mathematical model of MMC chemotherapy for non-invasive bladder cancer treatment

Mitomycin-C (MMC) chemotherapy is a well-established anti-cancer treatment for non-muscle-invasive bladder cancer (NMIBC). However, despite comprehensive biological research, the complete mechanism of action and an ideal regimen of MMC have not been elucidated. In this study, we present a theoretical investigation of NMIBC growth and its treatment by continuous administration of MMC chemotherapy. Using temporal ordinary differential equations (ODEs) to describe cell populations and drug molecules, we formulated the first mathematical model of tumor-immune interactions in the treatment of MMC for NMIBC, based on biological sources. Several hypothetical scenarios for NMIBC under the assumption that tumor size correlates with cell count are presented, depicting the evolution of tumors classified as small, medium, and large. These scenarios align qualitatively with clinical observations of lower recurrence rates for tumor size ≤ 30[mm] with MMC treatment, demonstrating that cure appears up to a theoretical x[mm] tumor size threshold, given specific parameters within a feasible biological range. The unique use of mole units allows to introduce a new method for theoretical pre-treatment assessments by determining MMC drug doses required for a cure. In this way, our approach provides initial steps toward personalized MMC chemotherapy for NMIBC patients, offering the possibility of new insights and potentially holding the key to unlocking some of its mysteries.

Collagen 17A1 in the Urothelium Regulates Epithelial Cell Integrity and Local Immunologic Responses in Obstructive Uropathy

Collagen 17A1 (COL17A1), an epidermal hemidesmosome component, is ectopically induced in the urothelium of mouse and human renal pelvis (RP) in parallel with urinary tract-associated lymphoid structure development. Here, we found that COL17A1 was induced in obstructive uropathy-prone ureter of humans and cats. To ascertain its function, murine urinary organs with unilateral ureteral obstruction (UUO) were analyzed during 1 week after surgery. One day after UUO, COL17A1 expression increased in urothelial cells of RP and ureter, and was positively correlated with renal tubulointerstitial lesions. A portion of RP where the smooth muscle layer from the ureter was interrupted was sensitive to urothelium deciduation and COL17A1 induction, showing urine leaked from the RP lumen into the parenchyma. After urine stimulation, cultured immune cells expressed Cxcl2, also up-regulated in CD11b+ cells following COL17A1 stimulation. One day after UUO, CXCL2+ CD11b+ cells infiltrated the urothelium-disrupted area; however, these numbers were significantly lower in Col17a1-deficient mice. COL17A1+ urothelial cells partially co-expressed cytokeratin-14, a progenitor cell marker for urothelium, whereas Col17a1-deficient mice had lower numbers of cytokeratin-14+ cells. Gene Ontology analysis revealed that expression of epithelial- and immune-associated genes was up-regulated and down-regulated, respectively, in the ureter of Col17a1-deficient mice 4 days after UUO. Thus, COL17A1 maintains urothelium integrity by regulating urothelial cell adhesion, proliferation, and differentiation, and activates local immune responses during obstructive uropathy in mammals.

Distinct effects of Fgf7 and Fgf10 on the terminal differentiation of murine bladder urothelium revealed using an organoid culture system

BACKGROUND

Dysregulation of the terminal differentiation of bladder urothelium is associated with the pathogenesis of urinary tract disorders. Fibroblast growth factor (Fgf)7 and Fgf10 stimulate urothelial proliferation; however, their roles in cellular differentiation remain unclear. In this study, we used an organoid system to investigate the roles of these Fgfs in regulating bladder urothelium differentiation and identify their distribution patterns in the mouse bladder.

METHODS

Adult bladder epithelia (AdBE) isolated from adult mouse bladder tissues (AdBTs) were used to culture adult bladder organoids (AdBOs) in the presence of Fgf7 and Fgf10. The differentiation status of the cells in AdBTs, AdBEs, AdBOs, and neonatal bladder tissues (NeoBTs) was analyzed via quantitative real-time-PCR for the presence of undifferentiated cell markers (Krt5, Trp63, and Krt14) and differentiated cell markers (Krt20, Upk1a, Upk2, and Upk3a). Organoid cell proliferation was assessed by counting cell numbers using the trypan blue method. The effects of Fgf7 and Fgf10 on organoid differentiation were assessed using different doses of Fgfs, and the involvement of peroxisome proliferator-activated receptor γ (PPARγ) signaling in these processes was tested by introducing a PPARγ agonist (Rosiglitazone) and antagonist (T0070907) to the culture. The expression patterns of Fgf7 and Fgf10 were examined via in situ hybridization of AdBTs.

RESULTS

AdBOs showed higher expression of undifferentiated cell markers and lower expression of differentiated cell markers than AdBTs, NeoBTs, and AdBEs, indicating the relatively immature state of AdBOs. Differentiation of AdBOs was enhanced by Rosiglitazone and Fgf7, suggesting an interplay of intracellular signals between Fgf7 and PPARγ. Co-addition of T0070907 suppressed Fgf7-mediated differentiation, demonstrating that PPARγ is activated downstream of Fgf7 to promote cellular differentiation into umbrella cells. Furthermore, we found that Fgf7 is predominantly expressed in the umbrella cells of the urothelium, whereas Fgf10 is predominantly expressed in the urothelium and stroma of AdBTs.

CONCLUSIONS

We demonstrated that unlike Fgf10, Fgf7 induces cellular differentiation via PPARγ activity and has a unique tissue distribution pattern in the adult bladder. Further studies on the Fgf7-PPARγ signaling axis would provide insights into the differentiation mechanisms toward functional umbrella cells and the pathogenesis of several urinary tract diseases.

Molecular classification of urothelial bladder carcinoma

Urothelial bladder carcinoma (UC) ranks among the top ten most commonly diagnosed cancers worldwide on an annual basis. The standardized classification system for urothelial bladder tumors is the Tumor, Node, Metastasis classification, which reflects differences between non-muscle-invasive bladder carcinoma (NMIBC) and muscle-invasive bladder carcinoma (MIBC) and it depends on the extent to which tumor has infiltrated the bladder wall and other tissues and organs. NMIBC and MIBC exhibit great intrinsic heterogeneity regarding different prognoses, survival, progression, and treatment outcomes. In recent years, studies based on mRNA expression profiling revealed the existence of biologically relevant molecular subtypes of UC, which show variant molecular features that can provide more precise stratification of UC patients. Here, we present a complex classification of UC based on mRNA expression studies and molecular subtypes of NMIBC and MIBC in detail with regard to different mRNA expression profiles, mutational signatures, and infiltration by non-tumor cells. The possible impact of molecular subtyping on treatment decisions and patients' outcomes is outlined, too.

Single-cell sequencing technologies in bladder cancer research: Applications and challenges

Bladder cancer is among the most common malignant tumors with highly heterogeneous molecular characteristics. Despite advancements of the available therapeutic options, several bladder cancer patients exhibit unsatisfactory clinical outcomes. The lack of specific biomarkers for effective targeted therapy or immunotherapy remains a major obstacle in treating bladder cancer. The rapid development of single-cell techniques is transforming our understanding of the intra-tumoral heterogeneity, thereby providing us with a powerful high-throughput sequencing tool that can reveal tumorigenesis, progression, and invasion in bladder tumors. In this review, we summarise and discuss how single-cell sequencing technologies have been applied in bladder cancer research, to advance our collective knowledge on the heterogeneity of bladder tumor cells, as well as to provide new insights into the complex ecosystem of the tumor microenvironment. The application of single-cell approaches also uncovers the therapeutic resistance mechanism in bladder cancer and facilitates the detection of urinary-exfoliated tumor cells. Moreover, benefiting from the powerful technical advantages of single-cell techniques, several key therapeutic targets and prognostic models of bladder cancer have been identified. It is hoped that this paper can provide novel insights into the precision medicine of bladder cancer.

The dynamic roles of the bladder tumour microenvironment

Bladder cancer is a prevalent but currently understudied cancer type and patient outcomes are poor when it progresses to the muscle-invasive stage. Current research in bladder cancer focuses on the genetic and epigenetic alterations occurring within the urothelial cell compartment; however, the stromal compartment receives less attention. Dynamic changes and intercellular communications occur in the tumour microenvironment (TME) of the bladder - a new concept and niche that we designate as the bladder TME (bTME) - during tumour evolution, metastatic progression and in the context of therapeutic response. Collagens and their cognate receptors, the discoidin domain receptors, have a role in various steps of the metastatic cascade and in immune checkpoint resistance. Furthermore, the presence of another TME niche, the metastatic TME (met-TME), is a novel concept that could support divergent progression of metastatic colonization in different organs, resulting in distant metastases with distinct characteristics and genetics from the primary tumour. The stroma has divergent roles in mediating therapeutic response to BCG immunotherapy and immune checkpoint inhibitors, as well as conventional chemotherapy or trimodality therapy (that is, maximal transurethral resection of bladder tumour, chemotherapy and radiotherapy). The local bTME and distant met-TME are currently conceptually and therapeutically unexploited niches that should be actively investigated. New biological insights from these TMEs will enable rational design of strategies that co-target the tumour and stroma, which are expected to improve the outcomes of patients with advanced bladder cancer.

Cytotoxic Homo- and Hetero-Dimers of o-toluidine, o-anisidine, and Aniline Formed by In Vitro Metabolism

Several aromatic amine compounds are urinary bladder carcinogens. Activated metabolites and DNA adducts of polycyclic aromatic amines, such as 4-aminobiphenyl, have been identified, whereas those of monocyclic aromatic amines, such as o-toluidine (o-Tol), o-anisidine (o-Ans), and aniline (Ani), have not been completely determined. We have recently reported that o-Tol and o-Ans are metabolically converted in vitro and in vivo to cytotoxic and mutagenic p-semidine-type dimers, namely 2-methyl-N⁴-(2-methylphenyl) benzene-1,4-diamine (MMBD) and 2-methoxy-N⁴-(2-methoxyphenyl) benzene-1,4-diamine (MxMxBD), respectively, suggesting their roles in urinary bladder carcinogenesis. In this study, we found that when o-Tol and o-Ans were incubated with S9 mix, MMBD and MxMxBD as well as two isomeric heterodimers, MMxBD and MxMBD, were formed. Therefore, any two of o-Tol, o-Ans, and Ani (10 mM each) were incubated with the S9 mix for up to 24 h and then subjected to LC-MS to investigate their metabolic kinetics. Metabolic conversions to all nine kinds of p-semidine-type homo- and hetero-dimers were observed, peaking at 6 h of incubation with the S9 mix; MxMxBD reached the peak at 6.1 ± 1.4 μM. Homo- and hetero-dimers containing the o-Ans moiety in the diamine structure showed a faster dimerization ratio, whereas levels of these dimers, such as MxMxBD, markedly declined with further incubation. Dimers containing o-Tol and Ani were relatively stable, even after incubation for 24 h. The electron-donating group of the o-Ans moiety may be involved in rapid metabolic conversion. In the cytotoxic assay, dimers with an o-Ans moiety in the diamine structure and MMBD showed approximately two- to four-fold higher cytotoxicity than other dimers in human bladder cancer T24 cells. These chemical and biological properties of homo- and hetero-dimers of monocyclic aromatic amines may be important when considering the combined exposure risk for bladder carcinogenesis.

Are We Ready to Implement Molecular Subtyping of Bladder Cancer in Clinical Practice? Part 1: General Issues and Marker Expression

Bladder cancer (BC) is a heterogeneous disease with highly variable clinical and pathological features, and resulting in different outcomes. Such heterogeneity ensues from distinct pathogenetic mechanisms and may consistently affect treatment responses in single patients. Thus, over the last few years, several groups have developed molecular classification schemes for BC, mainly based on their mRNA expression profiles. A “consensus” classification has recently been proposed to combine the published systems, agreeing on a six-cluster scheme with distinct prognostic and predictive features. In order to implement molecular subtyping as a risk-stratification tool in routine practice, immunohistochemistry (IHC) has been explored as a readily accessible, relatively inexpensive, standardized surrogate method, achieving promising results in different clinical settings. The first part of this review deals with the steps resulting in the development of a molecular subtyping of BC, its prognostic and predictive implications, and the main features of immunohistochemical markers used as surrogates to stratify BC into pre-defined molecular clusters.

Persistent γ-H2AX formation and expression of stem cell markers in N-butyl-N-(4-hydroxybutyl)nitrosamine-induced bladder carcinogenesis in rats

We investigated γ-H2AX formation, a biomarker of DNA damage, and expression of stem cell markers (SCMs), including cytokeratin 14, aldehyde dehydrogenase 1A1 (ALDH1A1), and CD44, in the development of rat bladder tumors induced by short-term administration of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Histopathological examination showed that diffuse simple hyperplasia of the bladder urothelium induced by BBN recovered to the normal-appearing urothelium after withdrawal, whereas focal proliferative lesions were newly developed and subsequently progressed to benign papilloma and carcinoma. Immunohistochemical analysis revealed that BBN-induced γ-H2AX formation and ALDH1A1 and CD44 expression persisted at higher levels in the normal-appearing urothelium than those in the control group for long periods after withdrawal. Since persistent chronic inflammation was observed even after withdrawal, targeted gene expression analysis of inflammation-related factors revealed 101 genes, including Stat3 and Myc, that showed persistent high expression. Pathway analysis suggested that Stat3 and/or Myc activation may be associated with SCM expression. We focused on hepatocyte growth factor (Hgf), one of the genes predicted in relation to Stat3/Myc, and confirmed that HGF-positive cells increased by BBN persisted in the normal-appearing urothelium after withdrawal and colocalized with γ-H2AX and SCMs. These results suggested that the long-term persistence of γ-H2AX formation and SCM expression, which occurred during the early stages of bladder tumorigenesis, is not a transient response to exposure and might contribute to bladder tumorigenesis. Although further studies are needed, BBN-induced rat bladder tumors may originate from focal hyperplasia arising from SCM-positive cells via activation of the STAT3/MYC pathway after DNA damage involving γ-H2AX formation.

The urothelium: a multi-faceted barrier against a harsh environment

All mucosal surfaces must deal with the challenge of exposure to the outside world. The urothelium is a highly specialized layer of stratified epithelial cells lining the inner surface of the urinary bladder, a gruelling environment involving significant stretch forces, osmotic and hydrostatic pressures, toxic substances, and microbial invasion. The urinary bladder plays an important barrier role and allows the accommodation and expulsion of large volumes of urine without permitting urine components to diffuse across. The urothelium is made up of three cell types, basal, intermediate, and umbrella cells, whose specialized functions aid in the bladder's mission. In this review, we summarize the recent insights into urothelial structure, function, development, regeneration, and in particular the role of umbrella cells in barrier formation and maintenance. We briefly review diseases which involve the bladder and discuss current human urothelial in vitro models as a complement to traditional animal studies.

The role of TAp63γ and P53 point mutations in regulating DNA repair, mutational susceptibility and invasion of bladder cancer cells

It has long been recognized that non-muscle-invasive bladder cancer (NMIBC) has a low propensity (20%) of becoming muscle-invasive (MIBC), and that MIBC carry many more p53 point mutations (p53m) than NMIBC (50% vs 10%). MIBC also has a higher mutation burden than NMIBC. These results suggest that DNA repair capacities, mutational susceptibility and p53m are crucial for MIBC development. We found MIBC cells are hypermutable, deficient in DNA repair and have markedly downregulated DNA repair genes, XPC, hOGG1/2 and Ref1, and the tumor suppressor, TAp63γ. In contrast, NMIBC cells are hyperactive in DNA repair and exhibit upregulated DNA repair genes and TAp63γ. A parallel exists in human tumors, as MIBC tissues have markedly lower DNA repair activity, and lower expression of DNA repair genes and TAp63γ compared to NMIBC tissues. Forced TAp63γ expression in MIBC significantly mitigates DNA repair deficiencies and reduces mutational susceptibility. Knockdown of TAp63γ in NMIBC greatly reduces DNA repair capacity and enhances mutational susceptibility. Manipulated TAp63γ expression or knockdown of p53m reduce the invasion of MIBC by 40–60%. However, the combination of p53m knockdown with forced TAp63γ expression reduce the invasion ability to nil suggesting that p53m contributes to invasion phenotype independent from TAp63γ. These results indicate that in BC, TAp63γ regulates DNA repair capacities, mutational susceptibility and invasion, and that p53m contribute to the invasion phenotype. We conclude that concurrent TAp63γ suppression and acquisition of p53m are a major cause for MIBC development.

Novel Mouse Models of Bladder Cancer Identify a Prognostic Signature Associated with Risk of Disease Progression

To study the progression of bladder cancer from non-muscle-invasive to muscle-invasive disease, we have developed a novel toolkit that uses complementary approaches to achieve gene recombination in specific cell populations in the bladder urothelium in vivo, thereby allowing us to generate a new series of genetically engineered mouse models (GEMM) of bladder cancer. One method is based on the delivery of adenoviruses that express Cre recombinase in selected cell types in the urothelium, and a second uses transgenic drivers in which activation of inducible Cre alleles can be limited to the bladder urothelium by intravesicular delivery of tamoxifen. Using both approaches, targeted deletion of the Pten and p53 tumor suppressor genes specifically in basal urothelial cells gave rise to muscle-invasive bladder tumors. Furthermore, preinvasive lesions arising in basal cells displayed upregulation of molecular pathways related to bladder tumorigenesis, including proinflammatory pathways. Cross-species analyses comparing a mouse gene signature of early bladder cancer with a human signature of bladder cancer progression identified a conserved 28-gene signature of early bladder cancer that is associated with poor prognosis for human bladder cancer and that outperforms comparable gene signatures. These findings demonstrate the relevance of these GEMMs for studying the biology of human bladder cancer and introduce a prognostic gene signature that may help to stratify patients at risk for progression to potentially lethal muscle-invasive disease. SIGNIFICANCE: Analyses of bladder cancer progression in a new series of genetically engineered mouse models has identified a gene signature of poor prognosis in human bladder cancer.

Urothelial cancer organoids: a tool for bladder cancer research

Background

Bladder cancer ranks among the top ten most common tumor types worldwide and represents a growing healthcare problem, accounting for a large part of total healthcare costs. Chemotherapy is effective in a subset of patients, while causing severe side effects. Tumor pathogenesis and drug resistance mechanisms are largely unknown. Precision medicine is failing in bladder cancer, as bladder tumors are genetically and molecularly very heterogeneous. Currently, therapeutic decision-making depends on assessing a single fragment of surgically acquired tumor tissue.

Objective

New preclinical model systems for bladder cancer are indispensable for developing therapeutic strategies tailored to individual patient and tumor characteristics. Organoids are small 3D tissue cultures that simulate small-size organs “in a dish” and tumoroids are a special type of cancer organoid (i.e., malignant tissue).

Materials and methods

Since 2016, we have collaborated with the renowned Hubrecht Institute to provide proof of concept of tissue-based bladder tumoroids mimicking parental tumors. We have developed a living biobank containing bladder organoids and tumoroids grown from over 50 patient samples, which reflect crucial aspects of bladder cancer pathogenesis.

Results

Histological and immunofluorescence analysis indicated that the heterogeneity and subclassification of tumoroids mimicked those of corresponding parental tumor samples. Thus, urothelial tumoroids mimic crucial aspects of bladder cancer pathogenesis.

Conclusion

Research with urothelial tumoroids will open up new avenues for bladder cancer pathogenesis and drug-resistance research as well as for precision medicine approaches.

WNT7B represses epithelial-mesenchymal transition and stem-like properties in bladder urothelial carcinoma

BACKGROUND

Recurrence and metastasis are the major problems of bladder urothelial carcinoma, which mainly attribute to tumor cell stemness, epithelial-mesenchymal transition (EMT) and chemoresistance.

METHODS

TCGA database was interrogated for gene mRNA expression in bladder urothelial carcinoma samples. CCLE database was interrogated for gene mRNA expression in bladder cancer cell lines. The correlation between two genes was analyzed by Pearson statistics. 37 human bladder urothelial carcinoma specimens were adopted for immunohistochemistry. Bladder cancer cells RT4, J82, and UM-UC-3 were used to carry out loss and gain of function studies. Kaplan-Meier method was performed to analyze the overall survival.

FINDINGS

WNT7B is downregulated in high-grade bladder urothelial carcinomas. Low WNT7B expression is associated with unfavorable prognosis. Loss and gain of function studies showed that WNT7B inhibits bladder urothelial carcinoma cell EMT, stem-like properties and chemoresistance. FZD5, a specific receptor for WNT7B, mediates WNT7B signaling. ELF3 is a downstream component of WNT7B signaling, which transcriptionally modulates NOTCH1, a tumor suppressor in bladder urothelial carcinoma.

INTERPRETATION

These data demonstrate that WNT7B/FZD5-ELF3-NOTCH1 signaling functions as a tumor-suppressing pathway in bladder urothelial carcinoma.

Oxidized low-density lipoprotein links hypercholesterolemia and bladder cancer aggressiveness by promoting cancer stemness

Hypercholesterolemia is a prevalent metabolic disorder that has been implicated in the development of steroid-targeted cancers. However, the link between hypercholesterolemia and urinary bladder cancer (UBC), a non-steroid-targeted cancer, remains unresolved. Here we show that diet- and Ldlr deficiency-induced hypercholesterolemia enhances both UBC stemness and progression. Inhibition of intestinal cholesterol absorption by Ezetimibe reversed diet-induced hypercholesterolemia and cancer stemness. As a key component in hypercholesterolemic sera, oxidized low-density lipoprotein (ox-LDL), but not native low-density lipoprotein-cholesterol or metabolite 27-hydroxycholesterol, increased cancer stemness through its receptor CD36. Depletion of CD36, ectopic expression of an ox-LDL binding-disabled mutant form of CD36(K164A), and the neutralization of ox-LDL and CD36 via neutralizing antibodies all reversed ox-LDL-induced cancer stemness. Mechanistically, ox-LDL enhanced the interaction of CD36 and JAK2, inducing phosphorylation of JAK2 and subsequently activating STAT3 signaling, which was not mediated by JAK1 or Src in UBC cells. Finally, ox-LDL levels in serum predicted poor prognosis, and the ox-LDLhigh signature predicted worse survival in UBC patients. These findings indicate that ox-LDL links hypercholesterolemia with UBC progression by enhancing cancer stemness. Lowering serum ox-LDL or targeting the CD36/JAK2/STAT3 axis might serve as a potential therapeutic strategy for UBCs with hypercholesterolemia. Moreover, elevated ox-LDL may serve as a biomarker for UBC.

Robust Prognostic Subtyping of Muscle-Invasive Bladder Cancer Revealed by Deep Learning-Based Multi-Omics Data Integration

Muscle-invasive bladder cancer (MIBC) is the most common urinary system carcinoma associated with poor outcomes. It is necessary to develop a robust classification system for prognostic prediction of MIBC. Recently, increasing omics data at different levels of MIBC were produced, but few integration methods were used to classify MIBC that reflects the patient’s prognosis. In this study, we constructed an autoencoder based deep learning framework to integrate multi-omics data of MIBC and clustered samples into two different subgroups with significant overall survival difference (P = 8.11 × 10^-5). As an independent prognostic factor relative to clinical information, these two subtypes have some significant genomic differences. Remarkably, the subtype of poor prognosis had significant higher frequency of chromosome 3p deletion. Immune decomposition analysis results showed that these two MIBC subtypes had different immune components including macrophages M1, resting NK cells, regulatory T cells, plasma cells, and naïve B cells. Hallmark gene set enrichment analysis was performed to investigate the functional character difference between these two MIBC subtypes, which revealed that activated IL-6/JAK/STAT3 signaling, interferon-alpha response, reactive oxygen species pathway, and unfolded protein response were significantly enriched in upregulated genes of high-risk subtype. We constructed MIBC subtyping models based on multi-omics data and single omics data, respectively, and internal and external validation datasets showed the robustness of the prediction model as well as its ability of prognosis (P < 0.05 in all datasets). Finally, through bioinformatics analysis and immunohistochemistry experiments, we found that KRT7 can be used as a biomarker reflecting MIBC risk.

Alternative models of cancer stem cells: The stemness phenotype model, 10 years later

The classical cancer stem cell (CSCs) theory proposed the existence of a rare but constant subpopulation of CSCs. In this model cancer cells are organized hierarchically and are responsible for tumor resistance and tumor relapse. Thus, eliminating CSCs will eventually lead to cure of cancer. This simplistic model has been challenged by experimental data. In 2010 we proposed a novel and controversial alternative model of CSC biology (the Stemness Phenotype Model, SPM). The SPM proposed a non-hierarchical model of cancer biology in which there is no specific subpopulation of CSCs in tumors. Instead, cancer cells are highly plastic in term of stemness and CSCs and non-CSCs can interconvert into each other depending on the microenvironment. This model predicts the existence of cancer cells ranging from a pure CSC phenotype to pure non-CSC phenotype and that survival of a single cell can originate a new tumor. During the past 10 years, a plethora of experimental evidence in a variety of cancer types has shown that cancer cells are indeed extremely plastic and able to interconvert into cells with different stemness phenotype. In this review we will (1) briefly describe the cumulative evidence from our laboratory and others supporting the SPM; (2) the implications of the SPM in translational oncology; and (3) discuss potential strategies to develop more effective therapeutic regimens for cancer treatment.

Mechanisms involved in selecting and maintaining neuroblastoma cancer stem cell populations, and perspectives for therapeutic targeting

Pediatric neuroblastomas (NBs) are heterogeneous, aggressive, therapy-resistant embryonal tumours that originate from cells of neural crest (NC) origin and in particular neuroblasts committed to the sympathoadrenal progenitor cell lineage. Therapeutic resistance, post-therapeutic relapse and subsequent metastatic NB progression are driven primarily by cancer stem cell (CSC)-like subpopulations, which through their self-renewing capacity, intermittent and slow cell cycles, drug-resistant and reversibly adaptive plastic phenotypes, represent the most important obstacle to improving therapeutic outcomes in unfavourable NBs. In this review, dedicated to NB CSCs and the prospects for their therapeutic eradication, we initiate with brief descriptions of the unique transient vertebrate embryonic NC structure and salient molecular protagonists involved NC induction, specification, epithelial to mesenchymal transition and migratory behaviour, in order to familiarise the reader with the embryonic cellular and molecular origins and background to NB. We follow this by introducing NB and the potential NC-derived stem/progenitor cell origins of NBs, before providing a comprehensive review of the salient molecules, signalling pathways, mechanisms, tumour microenvironmental and therapeutic conditions involved in promoting, selecting and maintaining NB CSC subpopulations, and that underpin their therapy-resistant, self-renewing metastatic behaviour. Finally, we review potential therapeutic strategies and future prospects for targeting and eradication of these bastions of NB therapeutic resistance, post-therapeutic relapse and metastatic progression.

Subtype-associated epigenomic landscape and 3D genome structure in bladder cancer

Muscle-invasive bladder cancers are characterized by their distinct expression of luminal and basal genes, which could be used to predict key clinical features such as disease progression and overall survival. Transcriptionally, FOXA1, GATA3, and PPARG are shown to be essential for luminal subtype-specific gene regulation and subtype switching, while TP63, STAT3, and TFAP2 family members are critical for regulation of basal subtype-specific genes. Despite these advances, the underlying epigenetic mechanisms and 3D chromatin architecture responsible for subtype-specific regulation in bladder cancer remain unknown. RESULT: We determine the genome-wide transcriptome, enhancer landscape, and transcription factor binding profiles of FOXA1 and GATA3 in luminal and basal subtypes of bladder cancer. Furthermore, we report the first-ever mapping of genome-wide chromatin interactions by Hi-C in both bladder cancer cell lines and primary patient tumors. We show that subtype-specific transcription is accompanied by specific open chromatin and epigenomic marks, at least partially driven by distinct transcription factor binding at distal enhancers of luminal and basal bladder cancers. Finally, we identify a novel clinically relevant transcription factor, Neuronal PAS Domain Protein 2 (NPAS2), in luminal bladder cancers that regulates other subtype-specific genes and influences cancer cell proliferation and migration. CONCLUSION: In summary, our work identifies unique epigenomic signatures and 3D genome structures in luminal and basal urinary bladder cancers and suggests a novel link between the circadian transcription factor NPAS2 and a clinical bladder cancer subtype.

Magnetic Nanoparticle-Based Hyperthermia Mediates Drug Delivery and Impairs the Tumorigenic Capacity of Quiescent Colorectal Cancer Stem Cells

Cancer stem cells (CSCs) are the tumor cell subpopulation responsible for resistance to chemotherapy, tumor recurrence, and metastasis. An efficient therapy must act on low proliferating quiescent-CSCs (q-CSCs). We here investigate the effect of magnetic hyperthermia (MHT) in combination with local chemotherapy as a dual therapy to inhibit patient-derived colorectal qCR-CSCs. We apply iron oxide nanocubes as MHT heat mediators, coated with a thermoresponsive polymer (TR-Cubes) and loaded with DOXO (TR-DOXO) as a chemotherapeutic agent. The thermoresponsive polymer releases DOXO only at a temperature above 44 °C. In colony-forming assays, the cells exposed to TR-Cubes with MHT reveal that qCR-CSCs struggle to survive the heat damage and, with a due delay, restart the division of dormant cells. The eradication of qCR-CSCs with a complete stop of the colony formation was achieved only with TR-DOXO when exposed to MHT. The in vivo tumor formation study confirms the combined effects of MHT with heat-mediated drug release: only the group of animals that received the CR-CSCs pretreated, in vitro, with TR-DOXO and MHT lacked the formation of tumor even after several months. For DOXO-resistant CR-CSCs cells, the same results were shown, in vitro, when choosing the drug oxaliplatin rather than DOXO and applying MHT. These findings emphasize the potential of our nanoplatforms as an effective patient-personalized cancer treatment against qCR-CSCs.

Analysis of mRNA expression differences in bladder cancer metastasis based on TCGA datasets

OBJECTIVE

To investigate the metastatic mechanism of muscle invasive bladder cancer (MIBC), which accounts for approximately 30% of all bladder cancer cases, and is a considerable medical problem with high metastatic and mortality rates.

METHODS

The mRNA levels of patients with metastatic MIBC and nonmetastatic MIBC from The Cancer Genome Atlas dataset were compared. An integrated bioinformatics analysis was performed of the differentially expressed genes (DEGs), and analyses of Gene Ontology, Kyoto Encyclopaedia of Genes and Genomes pathway, protein-protein interaction, and survival were performed to investigate differences between metastatic and nonmetastatic MIBC.

RESULTS

Data from 264 patients were included (131 with, and 133 without, metastasis). A total of 385 significantly DEGs were identified, including 209 upregulated genes and 176 downregulated genes. Based on results using the STRING database and the MCODE plugin of Cytoscape software, two clusters were obtained. Moreover, two genes were identified that may be valuable for prognostic analysis: Keratin 38, type I (KRT38) and Histone cluster 1, H3f (HIST1H3F).

CONCLUSION

The KRT38 and HIST1H3F genes may be important in metastasis of MIBC.

The prognostic value of cytokeratin and extracellular collagen expression in urinary bladder cancer

BACKGROUND

Expression levels of collagens have been implicated in the progression of various cancers and interact with cytokeratins, but are not well studied in bladder cancer (BC). Therefore, we analyzed the gene and protein expression levels of collagen 1A1 (Col1a1/COL1A1), collagen 3A1 (col3a1/COL3A1), collagen 5A2 (col5a2/COL5A2), cytokeratin 14 (krt14/CK14), and cytokeratin 17 (krt17/CK17) in urothelial BC samples of different stages.

METHODS

In total, 102 fresh frozen and 190 formalin fixed and paraffin embedded (FFPE) samples were tested using immunohistochemistry and RT-qPCR. Expression levels were correlated to clinicopathological and follow-up data.

RESULTS

Col1a1, col3a1, col5a2 and krt14 mRNA levels were significantly overexpressed in high-grade and muscle-invasive BC (MIBC) compared to low-grade and non-muscle invasive BC (NMIBC) cases. Disease-specific survival (DSS) was shorter in patients with high expression levels of col1a1 (p = 0.004), col3a1 (p = 0.004), and col5a2 (p = 0.028). CK14 (p = 0.020), COL3A1 (p = 0.006) and Col5A2 (p = 0.006) protein expression levels were significantly higher and protein expression levels of CK17 (p = 0.05) significantly lower in MIBC compared to NMIBC. Furthermore, CK14 (p = 0.002) and COL5A2 (p = 0.006) protein expressions were significantly higher in high-grade compared to low-grade BC. DSS was shorter in patients with high expression levels of COL5A2 (p = 0.033) and CK14 (p = 0.042).

CONCLUSION

Expression changes of collagens and cytokeratins are univariable prognostic markers in BC.

Loss of Fibroblast Growth Factor Receptor 2 (FGFR2) Leads to Defective Bladder Urothelial Regeneration after Cyclophosphamide Injury

Cyclophosphamide may cause hemorrhagic cystitis and eventually bladder urothelial cancer. Genetic determinants for poor outcomes are unknown. We assessed actions of fibroblast growth factor receptor (FGFR) 2 in urothelium after cyclophosphamide exposure. Conditional urothelial deletion of Fgfr2 (Fgfr2KO) did not affect injury severity or proliferation of keratin 14⁺ (KRT14⁺) basal progenitors or other urothelial cells 1 day after cyclophosphamide exposure. Three days after cyclophosphamide exposure, Fgfr2KO urothelium had defective regeneration, fewer cells, larger basal cell bodies and nuclei, paradoxical increases in proliferation markers, and excessive replication stress versus controls. Fgfr2KO mice had evidence of pathologic basal cell endoreplication associated with absent phosphorylated ERK staining and decreased p53 expression versus controls. Mice with conditional deletion of Fgfr2 in urothelium enriched for KRT14⁺ cells reproduced Fgfr2KO abnormalities after cyclophosphamide exposure. Fgfr2KO urothelium had defects up to 6 months after injury versus controls, including larger basal cells and nuclei, more persistent basal and ectopic lumenal KRT14⁺ cells, and signs of metaplasia (attenuated E-cadherin staining). Mice missing one allele of Fgfr2 also had (less severe) regeneration defects and basal cell endoreplication 3 days after cyclophosphamide exposure versus controls. Thus, reduced FGFR2/ERK signaling apparently leads to abnormal urothelial repair after cyclophosphamide exposure from pathologic basal cell endoreplication. Patients with genetic variants in FGFR2 or its ligands may have increased risks of hemorrhagic cystitis or urothelial cancer from persistent and ectopic KRT14⁺ cells.

Integrative multi-omics analysis of muscle-invasive bladder cancer identifies prognostic biomarkers for frontline chemotherapy and immunotherapy

Only a subgroup of patients with muscle-invasive bladder cancer (MIBC) are responders toward cisplatin-based chemotherapy and PD-L1 blockade immunotherapy. There is a clinical need to identify MIBC molecular subtypes and biomarkers for patient stratification toward the therapies. Here, we performed an integrative clustering analysis of 388 MIBC samples with multi-omics data and identified basal and luminal/differentiated integrative subtypes and derived a 42 gene panel for classification of MIBC. Using nine additional gene expression data (n = 844), we demonstrated the prognostic value of the 42 basal-luminal genes. The basal subtype was associated with worse overall survival in patients receiving no neoadjuvant chemotherapy (NAC), but better overall survival in patients receiving NAC in two clinical trials. Each of the subtypes could be further divided into chr9 p21.3 normal or loss subgroup. The patients with low expression of MTAP/CDKN2A/2B (indicative of chr9 p21.3 loss) had a significantly lower response rate to anti-PD-L1 immunotherapy and worse survival than the patients with high expression of MTAP/CDKN2A/2B. This integrative analysis reveals intrinsic MIBC subtypes and biomarkers with prognostic value for the frontline therapies.

Long noncoding RNA MIR31HG and its splice variants regulate proliferation and migration: prognostic implications for muscle invasive bladder cancer

Background

Growing evidence supports the pivotal role of long non-coding RNAs (lncRNAs) in the regulation of cancer development and progression. Their expression patterns and biological function in muscle invasive bladder cancer (MIBC) remain elusive.

Methods

Transcript levels of lncRNA miR-31 host gene (MIR31HG) and its splice variants were measured in our MIBC cohort (n = 102) by qRT-PCR, and validated in silico by the TCGA cohort (n = 370). Kaplan-Meier and multiple Cox regression analysis were conducted to evaluate the survival significance of MIR31HG and its splice variants. Functional experiments were performed to examine the proliferation and migration abilities of MIR31HG and its splice variants by knockdown approaches.

Results

In this study, a decreased expression of MIR31HG was found in bladder cancer cells and tissues, except in the basal subtype. Survival analysis showed that high expression of MIR31HG was associated with poor overall survival (OS) and disease-free survival (DFS) in patients with MIBC of basal subtype. Two splice variants of MIR31HG lacking exon 1 (MIR31HGΔE1) and exon 3 (MIR31HGΔE3) were identified to have specific expression patterns in different molecular subtypes of our MIBC cohort. MIR31HGΔE3 was highly expressed in basal subtype tumors. A high expression of MIR31HGΔE1 and MIR31HGΔE3 was associated with worse OS and DFS in our cohort. In vitro experiments revealed that knockdown of MIR31HG inhibits cell proliferation, colony formation, and migration in bladder cancer. Cell proliferation and migration assays after knockdown of splice variants of MIR31HG showed corresponding roles for the full-length transcript.

Conclusions

Our study demonstrates that MIR31HG and its splice variants could serve as biomarkers for the classification and prognosis prediction of patients with MIBC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-020-01795-5.

Tumor heterogeneity in muscle-invasive bladder cancer

Muscle-invasive bladder cancer (MIBC), a highly heterogeneous disease, shows genomic instability and a high mutation rate. Clinical outcomes are variable and responses to conventional chemotherapy differ among patients (due to inter-patient tumor heterogeneity and inter-tumor heterogeneity) and even within each individual tumor (intra-tumor heterogeneity). Emerging evidence indicates that tumor heterogeneity may play an important role in cancer progression, resistance to therapy, and metastasis. Comprehensive molecular subtyping classifies MIBC into distinct categories that have potential to guide prognosis, patient stratification, and treatment. Genomic characterization of time-series analyses at the single cell level, and of cell-free circulating tumor DNA or circulating tumor cells, are emerging technologies that enable dissection of the complex clonal architecture of MIBC. This review provides insight into the clinical significance of the molecular mechanisms underlying heterogeneity, focusing on inter- and intra-tumor heterogeneity, with special emphasis on molecular classification and methods used to analyze the complex patterns involved.

Targeted Delivery of Therapeutics to Urological Cancer Stem Cells

Urological cancer refers to cancer in organs of the urinary system and the male reproductive system. It mainly includes prostate cancer, bladder cancer, renal cancer, etc., seriously threatening patients' survival. Although there are many advances in the treatment of urological cancer, approved targeted therapies often result in tumor recurrence and therapy failure. An increasing amount of evidence indicated that cancer stem cells (CSCs) with tumor-initiating ability were the source of treatment failure in urological cancer. The development of CSCstargeted strategy can provide a possibility for the complete elimination of urological cancer. This review is based on a search of PubMed, Google scholar and NIH database (http://ClinicalTrials.gov/) for English language articles containing the terms: "biomarkers", "cancer stem cells", "targeting/targeted therapy", "prostate cancer", bladder cancer" and "kidney cancer". We summarized the biomarkers and stem cell features of the prostate, bladder and renal CSCs, outlined the targeted strategies for urological CSCs from signaling pathways, cytokines, angiogenesis, surface markers, elimination therapy, differentiation therapy, immunotherapy, microRNA, nanomedicine, etc., and highlighted the prospects and future challenges in this research field.

Expression of stem cell markers as useful complementary factors in the early detection of urinary bladder carcinogens by immunohistochemistry for γ-H2AX

We previously demonstrated that immunohistochemistry for γ-H2AX, a biomarker of DNA damage, is useful for early detection of urinary bladder carcinogens in rats. In a 28-day repeated-dose study, γ-H2AX was shown to have high sensitivity for detection of bladder carcinogens. However, no reports have evaluated whether a combination of multiple biomarkers may further improve sensitivity. Accordingly, in this study, we aimed to evaluate the applicability of bladder tissue and cancer stem cell markers, including cytokeratin 14 (KRT14), aldehyde dehydrogenase 1A1 (ALDH1A1), and cluster of differentiation 44 (CD44), as complementary markers for early detection of bladder carcinogens. Bladder samples obtained from male F344 rats orally treated with 14 bladder carcinogens and five nonbladder carcinogens for 28 days were used for immunohistochemical analysis of stem cell markers. In the bladder carcinogen-treated rats, increases in KRT14, ALDH1A1, and CD44 expression were observed in 9, 10, and 10 out of 14 groups, respectively, whereas the five nonbladder carcinogens did not cause upregulation of these markers. Although most epithelial cells with KRT14 or ALDH1A1 expression were also positive for CD44, KRT14 and ALDH1A1 expression were mutually exclusive. Twelve bladder carcinogens showed increases in at least one of the three markers, indicating that the combined evaluation showed higher sensitivity than the use of individual markers alone. Importantly, two of three bladder carcinogens that did not induce γ-H2AX immunostaining showed stem cell marker expression. Our results demonstrated that these stem cell markers may be useful as complementary markers for γ-H2AX in evaluation of bladder carcinogens.

MEK is a promising target in the basal subtype of bladder cancer

While many resources exist for the drug screening of bladder cancer cell lines in 2D culture, it is widely recognized that screening in 3D culture is more representative of in vivo response. Importantly, signaling changes between 2D and 3D culture can result in changes to drug response. To address the need for 3D drug screening of bladder cancer cell lines, we screened 17 bladder cancer cell lines using a library of 652 investigational small-molecules and 3 clinically relevant drug combinations in 3D cell culture. Our goal was to identify compounds and classes of compounds with efficacy in bladder cancer. Utilizing established genomic and transcriptomic data for these bladder cancer cell lines, we correlated the genomic molecular parameters with drug response, to identify potentially novel groups of tumors that are vulnerable to specific drugs or classes of drugs. Importantly, we demonstrate that MEK inhibitors are a promising targeted therapy for the basal subtype of bladder cancer, and our data indicate that drug screening of 3D cultures provides an important resource for hypothesis generation.

A Novel Splice Variant of HYAL-4 Drives Malignant Transformation and Predicts Outcome in Patients with Bladder Cancer

PURPOSE

Poor prognosis of patients with muscle-invasive bladder cancer that often metastasizes drives the need for discovery of molecular determinants of bladder cancer progression. Chondroitin sulfate proteoglycans, including CD44, regulate cancer progression; however, the identity of a chondroitinase (Chase) that cleaves chondroitin sulfate from proteoglycans is unknown. HYAL-4 is an understudied gene suspected to encode a Chase, with no known biological function. We evaluated HYAL-4 expression and its role in bladder cancer.

EXPERIMENTAL DESIGN

In clinical specimens, HYAL-4 wild-type (Wt) and V1 expression was evaluated by RT-qPCR, IHC, and/or immunoblotting; a novel assay measured Chase activity. Wt and V1 were stably expressed or silenced in normal urothelial and three bladder cancer cell lines. Transfectants were analyzed for stem cell phenotype, invasive signature and tumorigenesis, and metastasis in four xenograft models, including orthotopic bladder.

RESULTS

HYAL-4 expression, specifically a novel splice variant (V1), was elevated in bladder tumors; Wt expression was barely detectable. V1 encoded a truncated 349 amino acid protein that was secreted. In bladder cancer tissues, V1 levels associated with metastasis and cancer-specific survival with high efficacy and encoded Chase activity. V1 cleaved chondroitin-6-sulfate from CD44, increasing CD44 secretion. V1 induced stem cell phenotype, motility/invasion, and an invasive signature. CD44 knockdown abrogated these phenotypes. V1-expressing urothelial cells developed angiogenic, muscle-invasive tumors. V1-expressing bladder cancer cells formed tumors at low density and formed metastatic bladder tumors when implanted orthotopically.

CONCLUSIONS

Our study discovered the first naturally-occurring eukaryotic/human Chase and connected it to disease pathology, specifically cancer. V1-Chase is a driver of malignant bladder cancer and potential predictor of outcome in patients with bladder cancer.

CK14 Expression Identifies a Basal/Squamous-Like Type of Papillary Non-Muscle-Invasive Upper Tract Urothelial Carcinoma

Object: CK14 expression is an important marker of basal/squamous-like (BASQ)-type muscle-invasive bladder carcinoma, and this molecularly defined subtype has a poor prognosis and a distinct response to chemotherapy. However, CK14 expression and its clinicopathological and molecular significance in papillary non-muscle-invasive upper tract urothelial carcinoma (NMIUTUC) remain unknown. Herein, we investigated the prognostic implications of immunohistochemical (IHC) staining for CK14 and the transcriptional characteristics associated with CK14 expression in papillary NMIUTUC. Materials and Methods: IHC staining for CK14 was conducted in 204 papillary NMIUTUC specimens. Positive CK14 IHC staining was defined as a positive signal in >0% of tumor cells. RNA sequencing data were analyzed from 8 papillary high-grade NMIUTUC specimens consisting of 4 CK14-positive and 4 CK14-negative tumors. Results: CK14 positivity was associated with a high TNM stage (p < 0.001) and a high World Health Organization grade (p = 0.003). Survival analysis showed that CK14 positivity was significantly associated with poor progression-free survival (p = 0.015; hazard ratio [HR] = 2.990; 95% confidence interval [CI] = 1.180-7.580) and was marginally associated with poor cancer-specific survival (p = 0.052; HR = 3.77; 95% CI = 0.900-15.780). Gene set enrichment analysis demonstrated that the CK14-positive tumors were associated with a basal subtype of breast cancer, squamous cell carcinoma development, p40, tumor necrosis factor α-nuclear factor-κB, and p53 pathways, and embryonic stem cells; these characteristics are reminiscent of the BASQ subtype. In addition, with a p < 0.05 and |fold change| ≥2 as the cutoffs, we identified 178 differentially expressed genes when comparing CK14-positive and CK14-negative tumors. Functional analysis of these genes revealed several networks and gene ontology terms related to the positive regulation of cellular proliferation in CK14-positive tumors. Consistent with these results, we demonstrated that the mean Ki-67 proliferative index was higher in CK14-positive tumors than it was in CK14-negative tumors (2.3 vs. 0.8%, respectively, p = 0.002). Conclusion: CK14-positive papillary NMIUTUC is an aggressive subtype with BASQ-like molecular characteristics and dynamic proliferative activity. We propose that CK14 IHC staining can be a useful biomarker of BASQ-type papillary NMIUTUC that can be applied in daily practice with the aim of precision oncology.

Knockdown of UTX/KDM6A Enriches Precursor Cell Populations in Urothelial Cell Cultures and Cell Lines

The histone demethylase UTX (gene: KDM6A) directs cell and tissue differentiation during development. Deleterious mutations in KDM6A occur in many human cancers, most frequently in urothelial carcinoma. The consequences of these mutations are poorly understood; plausibly, they may disturb urothelial differentiation. We therefore investigated the effects of UTX siRNA-mediated knockdown in two in vitro models of urothelial differentiation; namely, primary cultures of urothelial epithelial cells treated with troglitazone and PD153035 and the immortalized urothelial cell line HBLAK treated with high calcium and serum. In both models, efficient UTX knockdown did not block morphological and biochemical differentiation. An apparent delay was due to a cytotoxic effect on the cell cultures before the initiation of differentiation, which induced apoptosis partly in a p53-dependent manner. As a consequence, slowly cycling, smaller, KRT14^high precursor cells in the HBLAK cell line were enriched at the expense of more differentiated, larger, proliferating KRT14^low cells. UTX knockdown induced apoptosis and enriched KRT14^high cells in the BFTC-905 papillary urothelial carcinoma cell line as well. Our findings suggest an explanation for the frequent occurrence of KDM6A mutations across all stages and molecular subtypes of urothelial carcinoma, whereby loss of UTX function does not primarily impede later stages of urothelial differentiation, but favors the expansion of precursor populations to provide a reservoir of potential tumor-initiating cells.

Genetic and molecular biology of bladder cancer among Iranian patients

Background

Bladder cancer (BC) is the sixth common cancer among Iranians. Various risk factors such as smoking, body mass index, chronic infection, age, and genetic factors are associated with BC progression.

Methods

It has been shown that a significant ratio of patients have tumors with muscle bladder layer invasion and poor prognosis at the time of diagnosis. Therefore, the early detection of tumors is required to reduce the mortality rate of BC cases. Since there is a wide geographical incidence variation in BC in Iran, it seems that the ethnic and genetic factors can be the main risk factors among Iranian BC patients.

Results

For the first time, in present review we have summarized all of the reported genes among Iranian BC patients until now which were significantly associated with tumorigenesis. Moreover, we categorized all of the reported genes based on their cell and molecular functions to clarify the genetic and molecular biology of BC among Iranian population.

Conclusion

This review paves the way of determination of a population‐based genetic panel markers for the early detection of BC in this population.

Dose dependency of γ-H2AX formation in the rat urinary bladder treated with genotoxic and nongenotoxic bladder carcinogens

We previously reported that immunostaining for γ-H2AX, a biomarker of DNA damage, in the rat urinary bladder is useful for early detection of bladder carcinogens in 28-day toxicity studies. Here, we aimed to examine the dose dependency of γ-H2AX formation in the urinary bladder of rats. Male F344 rats (aged 6 weeks) were orally administered N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN; 0%, 0.0001%, 0.001%, 0.01%, 0.02%, or 0.05% in drinking water), a genotoxic bladder carcinogen, and melamine (0%, 0.3%, 1.0%, or 3.0% in the diet), a nongenotoxic bladder carcinogen, for 2 days or 4 weeks. Immunohistochemical analysis showed that γ-H2AX- and Ki67-positive epithelial cells in the bladder urothelium were significantly increased, with a clear dose dependency, in both BBN- and melamine-treated groups. Additionally, γ-H2AX formation was detected from the lower-dose group, without increased Ki67 expression or histopathologic findings. The ratios of γ-H2AX-positive cells at week 4 in both BBN- and melamine-treated groups were higher than those on day 2, indicating the time-dependent increase in γ-H2AX formation. Immunofluorescence double-staining revealed that γ-H2AX single-positive cells without Ki67 expression were often found in the urothelium of BBN-treated rats, whereas most γ-H2AX-positive cells were Ki67-positive in the melamine group. Our results demonstrated that γ-H2AX formation in the urinary bladder increased in a clear dose-dependent manner and that γ-H2AX immunostaining has the potential to detect bladder carcinogens after a 2-day administration. Furthermore, the association of genotoxic mechanisms in bladder carcinogenesis could be determined by analyzing the colocalization of γ-H2AX and Ki67 in the urothelium.

Functional study of acetaldehyde dehydrogenase 1 (ALDH1) in keratinocytes: microarray integrating bioinformatics approaches

The function of acetaldehyde dehydrogenase 1 (ALDH1) has been gradually elucidated in several diseases, especially in various cancers. However, the role of ALDH1 in skin-related diseases has been mostly unknown. Previously, we found that ALDH1 is involved in the pathogenesis of atopic dermatitis (AD). In this study, we used high-throughput screening (HTS) approaches to identify critical factors associated with ALDH1 in human keratinocytes to reveal its functions in skin. We overexpressed ALDH1 in human HaCaT keratinocytes and then conducted serial HTS studies, a DNA microarray and antibody array integrated with bioinformatics algorithms. Together, those tests identified several novel genes associated with the function of ALDH1 in keratinocytes, as well as AD, including CTSG and CCL11. In particular, GNB3, GHSR, TAS2R9, FFAR1, TAS2R16, CCL21, GPR32, NPFFR1, GPR15, FBXW12, CCL19, EDNRA, FFAR3, and RXFP3 proteins were consistently detected as hub proteins in the PPI maps. By integrating the datasets obtained from these HTS studies and using the strengths of each method, we obtained new insights into the functional role of ALDH1 in skin keratinocytes. The approach used here could contribute to the clinical understanding of ALDH1-associated applications for the treatment of AD.Communicated by Ramaswamy H. Sarma.

Reaching the End of the Line: Urinary Tract Infections

Urinary tract infections (UTIs) cause a substantial health care burden. UTIs (i) are most often caused by uropathogenic Escherichia coli (UPEC), (ii) primarily affect otherwise healthy females (50% of women will have a UTI), (iii) are associated with significant morbidity and economic impact, (iv) can become chronic, and (v) are highly recurrent. A history of UTI is a significant risk factor for a recurrent UTI (rUTI). In otherwise healthy women, an acute UTI leads to a 25 to 50% chance of rUTI within months of the initial infection. Interestingly, rUTIs are commonly caused by the same strain of E. coli that led to the initial infection, arguing that there exist host-associated reservoirs, like the gastrointestinal tract and underlying bladder tissue, that can seed rUTIs. Additionally, catheter-associated UTIs (CAUTI), caused by Enterococcus and Staphylococcus as well as UPEC, represent a major health care concern. The host's response of depositing fibrinogen at the site of infection has been found to be critical to establishing CAUTI. The Drug Resistance Index, an evaluation of antibiotic resistance, indicates that UTIs have become increasingly difficult to treat since the mid-2000s. Thus, UTIs are a "canary in the coal mine," warning of the possibility of a return to the preantibiotic era, where some common infections are untreatable with available antibiotics. Numerous alternative strategies for both the prevention and treatment of UTIs are being pursued, with a focus on the development of vaccines and small-molecule inhibitors targeting virulence factors, in the hopes of reducing the burden of urogenital tract infections in an antibiotic-sparing manner.

Cancer stem cell-specific expression profiles reveal emerging bladder cancer biomarkers and identify circRNA_103809 as an important regulator in bladder cancer

Bladder cancer stem cells (BCSCs), exhibiting self-renewal and differentiation capacities, may contribute to the tumor initiation, metastasis, recurrence and drug resistance of bladder cancer. However, the underlying functional mechanisms of BCSCs remain to be clarified. In this study, we describe the differentially-expressed mRNAs, lncRNAs, and circRNAs in BCSCs compared with that in bladder cancer non-stem cells (BCNSCs) through the transcriptome microarray data analysis using bladder cancer patients’ specimens. CircRNA_103809, the top one among the highly expressed circRNA identified in BCSCs, promotes the self-renewal, migration and invasion capabilities of bladder cancer by acting as a miR-511 sponge. Additionally, GO and KEGG pathway analysis suggest the differentially expressed genes identified may be involved in the cellular metabolism, differentiation and metastasis regulation of the cancer cells. Co-expression networks of lncRNAs/mRNAs and circRNAs/mRNAs constructed by WGCNA give a picture of the non-coding/coding RNAs regulating patterns in BCSCs. Notably, as core genes in the networks, AHCY, C6orf136 and LRIG1 show high potential to be prognosticators for bladder cancer. Therefore, further studies of non-coding RNA functional mechanisms in BCSCs is valuable for detecting the pathogenic mechanisms and discovering novel biomarkers in bladder cancer.

Tissue Profile of CDK4 and STAT3 as Possible Innovative Therapeutic Targets in Urinary Bladder Cancer

Bladder cancer represents a global health problem. It ranks ninth in worldwide cancer incidence. In Egypt, carcinoma of the bladder is the most prevalent cancer, Bladder cancer has the highest recurrence rate of any malignancy. Certainly, suitable molecular diagnostic markers are required to improve the early detection of bladder cancer and then to prolong survival of patients. The present study was aimed to explore the expression of CDk4 and STAT3 in bladder cancer tissues as prospective for target therapy. Our studied groups showed higher values of CDK4 and STAT3 expression in malignant tissues (SCC andUC collectively) compared to cystitis, however, significantly higher values of CDK4 and STAT3 expression were detected in UC group compared to SCC group. Urothelial carcinomas with papillary patterns showed lower parameters of CDK4 and STAT3 expression compared to the non-papillary variant, with significant differences. Higher grades of UC showed significantly higher parameters of CDK4 and STAT3 expression compared to low grade ones. Muscle invasion increases the level of CDK4 and STAT3 expression parameters, compared to non-muscle invasive UC.

Unraveling cancer lineage drivers in squamous cell carcinomas

Cancer hijacks embryonic development and adult wound repair mechanisms to fuel malignancy. Cancer frequently originates from de-regulated adult stem cells or progenitors, which are otherwise essential units for postnatal tissue remodeling and repair. Cancer genomics studies have revealed convergence of multiple cancers across organ sites, including squamous cell carcinomas (SCCs), a common group of cancers arising from the head and neck, esophagus, lung, cervix and skin. In this review, we summarize our current knowledge on the molecular drivers of SCCs, including these five major organ sites. We especially focus our discussion on lineage dependent driver genes and pathways, in the context of squamous development and stratification. We then use skin as a model to discuss the notion of field cancerization during SCC carcinogenesis, and cancer as a wound that never heals. Finally, we turn to the idea of context dependency widely observed in cancer driver genes, and outline literature support and possible explanations for their lineage specific functions. Through these discussions, we aim to provide an up-to-date summary of molecular mechanisms driving tumor plasticity in squamous cancers. Such basic knowledge will be helpful to inform the clinics for better stratifying cancer patients, revealing novel drug targets and providing effective treatment options.

Increased Expression Of SOX2 Predicts A Poor Prognosis And Promotes Malignant Phenotypes In Upper Tract Urothelial Carcinoma

Background

The transcription factor SRY-related HMG-box 2 (SOX2) plays important regulatory roles in diverse biological processes (cell proliferation, migration, invasion and tumorigenicity). However, the relationship between SOX2 and upper tract urothelial carcinoma (UTUC) have not been intensively investigated. This study aims to analyze the expression of SOX2 in UTUC as well as the predictive value for prognosis and the effect on tumor aggressiveness of SOX2.

Methods

Formalin-fixed, paraffin-embedded blocks containing samples from 341 patients with UTUC who underwent radical nephroureterectomy (RNU) at our institute were analyzed for SOX2 expression by immunohistochemistry (IHC). Associations between the SOX2 expression level and clinicopathological characteristics, disease-free survival (DFS) and cancer-specific survival (CSS) were analyzed. SOX2 expression in a normal urothelial cell line, urothelial carcinoma cell lines, 16 UTUC tissues and their pair-matched adjacent normal tissues was evaluated by RT-qPCR. Using RNA interference in vitro, the effects of SOX2 inhibition on cell proliferation, migration, invasion and tumorigenicity were determined.

Results

SOX2 expression was significantly upregulated in UTUC tissue samples compared with paired-adjacent nontumorous tissue samples. SOX2 expression was correlated with important clinicopathological features, including tumor stage, tumor grade, tumor architecture and the presence of glandular or sarcoma differentiation, and was an independent predictor of poor DFS and CSS. Further experiments indicated that SOX2 expression was higher in UTUC cell lines than in a normal urothelial cell line. Knocking down SOX2 expression could inhibit malignant phenotypes (cell proliferation, stemness, migration, invasion and tumorigenicity) in UTUC cells.

Conclusion

SOX2 is an independent prognostic marker of poor DFS and CSS in UTUC patients who have undergone RNU. Moreover, these data suggest that SOX2 may be a promising therapeutic target in UTUC.

Urothelial organoids originating from Cd49fhigh mouse stem cells display Notch-dependent differentiation capacity

Understanding urothelial stem cell biology and differentiation has been limited by the lack of methods for their unlimited propagation. Here, we establish mouse urothelial organoids that can be maintained uninterruptedly for >1 year. Organoid growth is dependent on EGF and Wnt activators. High CD49f/ITGA6 expression features a subpopulation of organoid-forming cells expressing basal markers. Upon differentiation, multilayered organoids undergo reduced proliferation, decreased cell layer number, urothelial program activation, and acquisition of barrier function. Pharmacological modulation of PPARγ and EGFR promotes differentiation. RNA sequencing highlighted genesets enriched in proliferative organoids (i.e. ribosome) and transcriptional networks involved in differentiation, including expression of Wnt ligands and Notch components. Single-cell RNA sequencing (scRNA-Seq) analysis of the organoids revealed five clusters with distinct gene expression profiles. Together, with the use of γ-secretase inhibitors and scRNA-Seq, confirms that Notch signaling is required for differentiation. Urothelial organoids provide a powerful tool to study cell regeneration and differentiation.

WNT/β-catenin signaling in urothelial carcinoma of bladder

Urothelial carcinoma of bladder is the second most prevalent genitourinary disease. It is a highly heterogeneous disease as it represents a spectrum of neoplasms, including non-muscle invasive bladder cancer (NMIBC), muscle invasive bladder cancer (MIBC) and metastatic lesions. Genome-wide approaches and candidate gene analysis suggest that malignant transformation of the bladder is multifactorial and a multitude of genes are involved in the development of MIBC or NMIBC phenotypes. Wnt signaling is being examined to control and maintain balance between stemness and differentiation in adult stem cell niches. Owing to its participation in urothelial development and maintenance of adult urothelial tissue homeostasis, the components of Wnt signaling are reported as an important diagnostic and prognostic markers as well as novel therapeutic targets. Mutations/epigenetic alterations in the key molecules of Wnt/β-catenin canonical pathway have been linked with tumorigenesis, development of drug resistance and enhanced survival. Present review extends our understanding on the functions of key regulatory molecules of canonical Wnt/β-catenin pathway in urothelial tumorigenesis by inducing cancer stem cell phenotype (UCSCs). UCSCs may be responsible for tumor heterogeneity, high recurrence rates and complex biological behavior of bladder cancer. Therefore, understanding the role of UCSCs and the regulatory mechanisms that are responsible for high relapse rates and metastasis could help to develop pathway inhibitors and augment current therapies. Potential implications in the treatment of urothelial carcinoma of bladder by targeting this pathway primarily in UCSCs as well as in bulk tumor population that are responsible for high relapse rates and metastasis may facilitate potential therapeutic avenues and better prognosis.

Clinical outcomes of muscle invasive bladder Cancer according to the BASQ classification

Background

We evaluated the clinical efficacy and prognosis of muscle-invasive bladder cancer according to the basal/squamous-like (BASQ) classification system based on immunohistochemical staining [CK5/6(+), CK14(+), GATA3(−), and FOXA1(−)].

Methods

One hundred patients diagnosed with muscle-invasive bladder cancer (cT2-4 N0-3 M0) were included in the study. All patients underwent radical cystectomy after transurethral removal of bladder tumor. Immunostaining was performed for CK5/6, CK14, FOXA1, and GATA3 antibodies on tissue microarray slides, and expression patterns were quantitatively analyzed using a scanning program.

Results

The median follow-up time was 77.4 (interquartile range: 39–120.9) months. The mean age of the patients was 65.1 ± 11.2 years. FOXA1 or CK14 expression greater than 1% was respectively positively and negatively correlated with overall survival (OS; p = 0.011 and p = 0.042, respectively), cancer-specific survival (CSS; p = 0.050 for both), and recurrence-free survival (RFS; p = 0.018 and p = 0.040, respectively). For CK5/6+ and GATA3- or FOXA1- expression, 10% CK5/6+ cells were negatively correlated with OS (p = 0.032 and p = 0.039, respectively) and with RFS in combination with FOXA1- only (p = 0.050).

Conclusions

In this study, CK14 expression was associated with a poor prognosis. The new classification system of bladder cancer based on molecular characteristics is expected to helpful tool for the establishment of personalized treatment strategies and associated prediction of therapeutic responses.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6042-1) contains supplementary material, which is available to authorized users.

Long Pentraxin-3 Follows and Modulates Bladder Cancer Progression

Bladder tumors are a diffuse type of cancer. Long pentraxin-3 (PTX3) is a component of the innate immunity with pleiotropic functions in the regulation of immune response, tissue remodeling, and cancer progression. PTX3 may act as an oncosuppressor in different contexts, functioning as an antagonist of the fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) system, rewiring the immune microenvironment, or acting through mechanisms not yet fully clarified. In this study we used biopsies and data mining to assess that PTX3 is differentially expressed during the different stages of bladder cancer (BC) progression. BC cell lines, representative of different tumor grades, and transgenic/carcinogen-induced models were used to demonstrate in vitro and in vivo that PTX3 production by tumor cells decreases along the progression from low-grade to high-grade advanced muscle invasive forms (MIBC). In vitro and in vivo data revealed for the first time that PTX3 modulation and the consequent impairment of FGF/FGR systems in BC cells have a significant impact on different biological features of BC growth, including cell proliferation, motility, metabolism, stemness, and drug resistance. PTX3 exerts an oncosuppressive effect on BC progression and may represent a potential functional biomarker in BC evolution. Moreover, FGF/FGFR blockade has an impact on drug resistance and stemness features in BC.

Hyper-Activation of STAT3 Sustains Progression of Non-Papillary Basal-Type Bladder Cancer via FOSL1 Regulome

Urothelial bladder cancer (UBC) are classified into luminal and basal subtypes showing distinct molecular features and clinical behaviour. Recent in silico data have proposed the activation on the Signal Transducer and Activator of Transcription 3 (STAT3) as relevant transcription factor in UBC. To answer this question, we have combined the retrospective analysis of clinical samples, functional assays on cell lines, interrogation of public UBC datasets and a murine model of basal-type UBC. Immunohistochemistry on a retrospective UBC cohort uncovered that STAT3 Y705 phosphorylation (pSTAT3) is significantly increased in infiltrating basal-type UBC compared to luminal UBC. In vitro, STAT3 silencing in UBC cell lines significantly reduced tumor cell viability and invasion. Gene expression profile of UBC cell lines combined with the analysis of the Cancer Genome Atlas (TCGA) and GSE32894 UBC datasets showed that increased expression of a set of STAT3 targets predicts basal-type, propensity to local progression and worse prognosis. MYC and FOSL1 represent relevant STAT3 downstream targets, as validated by their co-localization in pSTAT3+ UBC cancer cells. These findings were largely reproduced in the BBN-induced murine model of basal-type UBC. Of note, FOSL1 protein resulted strongly expressed in the non-papillary UBC pathway and FOSL1-regulated transcripts were significantly enriched in the transition from NMIBC to MIBC, as indicated by the interrogation of the GSE32894 dataset. The blockade of the STAT3 pathway might represent a novel treatment option for these neoplasms. Monitoring pSTAT3 and the downstream targets, particularly FOSL1, could provide meaningful levels of UBC stratification.

Increased expression of DCLK1, a novel putative CSC maker, is associated with tumor aggressiveness and worse disease-specific survival in patients with bladder carcinomas

Doublecortin-like kinase 1 (DCLK1) has been characterized as a novel potential cancer stem cell (CSC) marker in several types of cancer. It is considered as one of the most specific markers for distinguishing colorectal CSCs from normal stem cells. Yet, there are limited reports on the role of DCLK1 as a putative CSC marker in bladder cancer. Using immunohistochemistry, DCLK1 expression was examined in a well-defined tissue microarray series of 472 bladder cancer tissues. The association between DCLK1 protein expression and clinicopathological features, as well as survival outcomes, was assessed. Our findings showed strong, moderate, and weak DCLK1 expression in 123 (26.1%), 230 (48.7%), and 119 (25.2%) of the bladder cancer specimens, respectively. Higher expression of DCLK1 was significantly associated with increase in histological grade (P ≤ .001), pT stage (P = .014), lamina propria (P = .006), and lamina propria/muscularis (L/M) involvement (P = .014). On multivariate analysis, pT stage (P < .001), histological grade (P = .021), and lamina propria involvement (P = .001) were independent prognostic factors in DCLK1 expression. Moreover, the expression of DCLK1 was found to be an independent marker of poor prognosis for disease- specific survival (DSS) (P = .048) in bladder carcinomas. Our observations showed that DCLK1 expression was associated with more aggressive tumor behavior, more advanced disease, and poorer DSS in patients with bladder carcinomas. However, any potential clinical applications of DCLK1 as a novel target molecule in bladder cancer patients would require further investigations.

Low doses of decitabine improve the chemotherapy efficacy against basal-like bladder cancer by targeting cancer stem cells

Low dose treatment with the DNA methylation inhibitor decitabine has been shown to be applicable for the management of certain types of cancer. However, its antitumor effect and mechanisms are context dependent and its activity has never been systematically studied in bladder cancer treatment. We used mouse models, cultured cell lines and patient-derived xenografts to demonstrate that low dose decitabine treatment remarkably enhanced the effects of cisplatin and gemcitabine on basal-like bladder cancer both in vivo and in vitro. Genetic lineage tracing revealed that the stemness of a bladder cancer stem cell population was inhibited by decitabine treatment in mice. These effects were accompanied by decreases in genome-wide DNA methylation, gene re-expression, and changes in key cellular regulatory pathways such as STAT3 signaling. These results indicate that this DNA-demethylating reagent is a promising therapeutic approach for basal-like bladder cancer treatment.