The Present and Future of Intravesical Therapy in Bladder Cancer

Intravesical therapy is the gold standard in the treatment of nonmuscle invasive bladder cancer (NMIBC). Despite the efficacy of intravesical therapies, the best treatment options are not determined yet. Development in research of bladder cancer shows several new intravesical drugs and its delivery systems. Additionally, the novel knowledge of bladder cancer immune reaction improves and provides ambitious treatment strategies. The future of NMIBC therapy will be changed by the development of immunotherapy and new technologies for device-assisted treatment. This review focuses on recent advances in the intravesical therapy of NMIBC, viral gene therapy, new technology of intravesical chemotherapy, and drug delivery system.

New Drugs for Bacillus Calmette Guérin-Unresponsive Nonmuscle Invasive Bladder Cancer

For intermediate- and high-risk nonmuscle invasive bladder cancer (NMIBC), intravesical Bacillus Calmette-Guérin (BCG) therapy is the standard adjuvant treatment following transurethral resection of bladder tumor. Although intravesical BCG therapy improves disease progression and bladder preservation in most patients, there are still a considerable number of BCG-unresponsive cases, for whom radical cystectomy (RC) is the recommended salvage treatment option. However, RC is associated with high morbidity and mortality rates, and alternative treatment options are needed. New approaches, such as intravesical chemotherapy, device-assisted treatments, immune checkpoint inhibitors, viral gene therapy, antibody-drug conjugates, fibroblast growth factor receptor inhibitors, and other novel agents are being investigated. This review aims to provide an overview of the recent trials for BCG-unresponsive NMIBC.

Clinical Implications of Urinary Microbiome in Bladder Cancer

Microbiomes are known to have a beneficial effect on human health by promoting the effective removal of improperly functioning immune cells and protecting the host from pathogen infection. On the other hand, these microbiomes are also known as the causative agent of numerous malignant tumors. Until now, the bladder has been regarded as aseptic, but the concept of the “sterile bladder” has been changed with the discovery of living bacteria embedded in the bladder with the recent development of polymerase chain reaction and culture techniques. This paper referred to the relationship between microbiome and bladder cancer. Microbiome will be able to be seen as a non-invasive biomarker to predict the success rate of intravesical bacillus Calmette-Guerin instillation treatment in patients of bladder cancer.

The Development of Antibody-Drug Conjugates for Urothelial Carcinoma Treatment

Urothelial cancer is the seventh most common cancer among men worldwide. Bacille de Calmette-Guérin is a type of anticancer immunotherapy that has been used to treat targeted bladder cancer, but the number of patients with treatment-refractory advanced urothelial cancer, patients has been increasing recently. To overcome this, enfortumab vedotin (novel nectin-4 targeting antibody-drug conjugate) known as antibody-drug conjugate (ADC), was approved. We describe the clinical development process of ADC and the potential for future development as a bladder cancer treatment.

The Effects of Recombinant Bacillus Calmette-Guérin Resistant to Antimicrobial Peptides on Orthotopic Bladder Cancer Mouse Model

Purpose@#Although Mycobacterium bovis Bacillus Calmette-Guérin (BCG) is the most widely used bladder cancer immunotherapy, innate immune responses involving antimicrobial peptides (AMPs) cause BCG failure. Here, we developed genetically modified recombinant BCG (rBCG) strains which escape AMPs and evaluate the efficacy and effects of rBCG. @*Materials and Methods@#We constructed rBCG strains expressing Streptococcal inhibitor of complement (Sic), which confers resistance to human α-defensin-1 and cathelicidin, and d-alanyl carrier protein ligase (dltA), which confers resistance to cationic AMPs. Sic and dltA were separately cloned into the pMV306 plasmid and introduced into BCG via electroporation. The efficacy of the Sic and dltA gene electroporation into BCG was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The internalization rates and anticancer effects of the rBCG strains containing Sic (rBCG-Sic) and dltA (rBCG-dltA) was evaluated by the orthotopic bladder cancer mouse model. @*Results@#The cycle quantification (Cq) values of rBCG-Sic (y=-4.8823x+13.645, R2=0.9996) and rBCG-dltA (y=-5.438x+11.641, R2=0.9995) were inverse correlations to the amount of Sic and dltA genes dose dependently. The mean introduction proportions of Sic and dltA genes into BCG by electroporation were 22.2%, 27.5% and showed constant efficacy. In the orthotopic bladder cancer mouse model, the relative internalization number of rBCG-Sic, and rBCG-dltA into bladder cell in mouse bladder were higher than that of BCG and the tumor volume at rBCG-Sic were lower than at BCG and rBCG-dltA at 11, 14 and 18 days. @*Conclusions@#Our results showed that constructed rBCG-Sic and rBCG-dltA by electroporation and the rBCG-Sic and rBCG-dltA can effectively escape BCG-stimulated AMPs, and significantly improved immunotherapeutic tools to treat bladder cancer in orthotopic bladder cancer mouse model.

Clinical Implications of Urinary Microbiome in Bladder Cancer

Microbiomes are known to have a beneficial effect on human health by promoting the effective removal of improperly functioning immune cells and protecting the host from pathogen infection. On the other hand, these microbiomes are also known as the causative agent of numerous malignant tumors. Until now, the bladder has been regarded as aseptic, but the concept of the “sterile bladder” has been changed with the discovery of living bacteria embedded in the bladder with the recent development of polymerase chain reaction and culture techniques. This paper referred to the relationship between microbiome and bladder cancer. Microbiome will be able to be seen as a non-invasive biomarker to predict the success rate of intravesical bacillus Calmette-Guerin instillation treatment in patients of bladder cancer.

Approaches for Personalized Drug Development in Bladder Cancer Patients

Bladder cancer, which affects the bladder mucosa, is the ninth most common disease worldwide. There are manytypes of cancerous tissue in the bladder. Most exhibit low malignancy, but their recurrence rate is higher incomparison to more malignant tissues. Only 10%–15% progress to invasive bladder cancer and metastasize tothe lung, liver, and bone, which is significantly difficult to treat. The anticancer efficacy developed for the treatmentof highly malignant bladder cancer does not equally apply to all patients, and the side effects vary. To solvethis problem, studies have been conducted on various verification systems and patient-specific drug development.For example, an organ-on-a-chip model using patient cancer cells is being actively researched as an anticancerdrug verification system. A study on screening anticancer drugs according to cancer biomarkers unique to individualpatients is also in progress. In addition, studies have recently been conducted on immune anticancer drugs thatexhibit excellent anticancer efficacy. This report discusses various validation systems and drug screening criteriafor the development of patient-specific drugs. We propose that it is possible to evaluate the efficacy of anticancerdrugs for each patient, understand drug mechanism patterns in humans, and develop treatment that preventscancer metastasis.

The Systematic Review of the Efficacy and Safety of Immune Checkpoint Inhibitor in Urological Cancers

To systematically review relevant literature on efficacy and safety of immune checkpoint inhibitors (ICIs) in patients with advanced and metastatic urothelial cell cancer (UCC), renal cell cancer (RCC), and prostate cancer. In platinum pretreated UCC, efficacy of pembrolizumab was superior to chemotherapy, with longer median overall survival (OS; 10.3 months vs. 7.4 months), a higher objective response rate (ORR; 21.1% vs. 11.4%, p=0.001), and a lower adverse event rate (60.9% vs. 90.2%). Three randomized controlled trials (RCTs) assessed the safety and efficacy of nivolumab in advanced RCC. The median OS (25.0 months vs. 19.6 months) and the ORR (25% vs. 5%) were higher in patients treated with nivolumab compared with second-line everolimus. In patients with metastatic castration-resistant prostate cancer, 2 RCTs were identified, which did not show significant benefits for ipilimumab over placebo. In UCC and RCC, there was no conclusive association between programmed cell death receptor ligand 1 (PD-L1) expression in tumor tissue and clinical outcome during pembrolizumab and nivolumab treatment, respectively. Therefore, in metastatic UCC and RCC, pembrolizumab and nivolumab have superior efficacy and safety to second-line chemotherapy and everolimus, respectively. No beneficial effect of ipilimumab was observed in prostate cancer patients. PD-L1 expression status is currently not suitable as a predictive marker for treatment outcome.

Bacillus Calmette-Guérin (BCG)-Cell Wall Skeleton as Immunotherapeutic Option for BCG-Refractory Superficial Bladder Cancer

Although intravesical instillation of Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the most successful cancer immunotherapy for superficial bladder cancer, the serious side effects are frequently arisen by using live mycobacteria. To allow less toxic and more potent immunotherapeutic agents following intravesical BCG treatment for superficial bladder cancer, noninfectious immunotherapeutic drug instead of live BCG would be highly desirable. Recently, immune-enhancing adjuvants are considered an effective vaccine immunotherapy for cancer, providing enhanced antitumor effects and boosted immunity. The BCG-cell wall skeleton (BCG-CWS), the main immune active center of BCG, is a potent candidate as a noninfectious immunotherapeutic drug instead of live BCG against bladder cancer. However, the most limited application for anticancer therapy, it is difficult to formulate a water-soluble BCG-CWS due to the aggregation of BCG-CWS in both aqueous and nonaqueous solvents. To overcome the insolubility and improve the internalization of BCG-CWS into bladder cancer cells, it should be developed the lipid nanoparticulation of BCG-CWS, resulting in improved dispensability, stability, and small size. In addition, powerful technology of delivery systems should be applied to enhance the internalization of BCG-CWS, such as encapsulated into lipid nanoparticles using novel packaging methods. Here, we describe the progress in research on effects of BCG-CWS for cancer immunotherapy, development of lipid-based solvent, and packaging method using nanoparticles with drug delivery system.

Application of Bioprinting to Cancer Research

Three-dimensional (3D) printing is an additive manufacturing process by which precursor materials are deposited layer by layer to form complex 3D geometries from computer-aided designs, and bioprinting offers the ability to create 3D architecture living cells. Bioprinting methods have been developed rapidly pattern living cells, biological macromolecules, and biomaterials, and an advantage of the 3D microenviroment over traditional 2-dimensional cell culture is the ability to obtain more accurate and reliable data from model about tumor formation, progression, and response to anticancer therapies. This review focuses on recent advances in the use of biopriniting technologies for cancer research, bioprinting physiologically relevant testing platforms for anticancer drug development, and computational modeling for improvement bioprinting technique.

The Overdiagnosis of Kidney Cancer in Koreans and the Active Surveillance on Small Renal Mass

While overtreatment in medical services had been the topic of interest among the medical community for a long time, there are numerous academic papers concerning over-diagnosis nowadays. The use of imaging studies for screening might lead to over-diagnosis of small renal masses (SRMs) therefore the incidence of kidney cancer increased 5 times higher than that of mortality in Korea between 2000 and 2011. The best treatment for SRMs had been debated and the present strategies include surgery, local treatment, and active surveillance. Competing risks to mortality should be considered to determine initial management strategies, and a period of initial active surveillance in patients with SRMs is safe. Tumor growth rate is the primary driver for delayed intervention of SRMs patients, and the risk of metastasis on active surveillance for SRMs is 1%–2% at 2-year follow-up.

Low-Dose Unenhanced Computed Tomography with Iterative Reconstruction for Diagnosis of Ureter Stones

PURPOSE: To study the clinical application of low-dose unenhanced computed tomography with iterative reconstruction technique (LDCT-IR) on renal colic in the emergency department. MATERIALS AND METHODS: We conducted a prospective, single-blinded, randomized, and non-inferiority study. From March 2014 to August 2015, 112 patients with renal colic were included, and were randomized to either LDCT-IR (n=46) or standard-dose unenhanced CT (SDCT) (n=66) groups. The accuracy of urolithiasis diagnosis was the primary endpoint of this study. Radiation dose, size and location of the stone, hydronephrosis, other diseases except urolithiasis, and results of treatment were analyzed between the two groups. RESULTS: The average effective dose radiation of SDCT was approximately four times higher than that of LDCT-IR (6.52 mSv vs. 1.63 mSv, p < 0.001). There was no significant difference in the accuracy of ureteral stone diagnosis between the two groups (LDCT-IR group: 96.97% vs. SDCT group: 98.96%, p=0.392). No significant difference was observed regarding the size and location of a stone, hydronephrosis, and diagnosis of other diseases, except urolithiasis. False negative results were found in two LDCT-IR patients and in one SDCT patient. In these patients, stones were misread as vascular calcification, and were difficult to diagnose because evidence of hydronephrosis and ureteral dilatation was not found. CONCLUSION: LDCT-IR, as a first-line imaging test, was non-inferior to SDCT with respect to diagnosis of ureter stones, and was clinically available for the evaluation of renal colic.

Identification of Downstream Genes of the mTOR Pathway that Predict Recurrence and Progression in Non-Muscle Invasive High-Grade Urothelial Carcinoma of the Bladder

Microarray analysis was used to investigate the lack of identified mammalian target of rapamycin (mTOR) pathway downstream genes to overcome cross-talk at non-muscle invasive high-grade (HG)-urothelial carcinoma (UC) of the bladder, gene expression patterns, gene ontology, and gene clustering by triple (p70S6K, S6K, and eIF4E) small interfering RNAs (siRNAs) or rapamycin in 5637 and T24 cell lines. We selected mTOR pathway downstream genes that were suppressed by siRNAs more than 2-fold, or were up-regulated or down-regulated by rapamycin more than 2-fold. We validated mTOR downstream genes with immunohistochemistry using a tissue microarray (TMA) of 125 non-muscle invasive HG-UC patients and knockout study to evaluate the synergistic effect with rapamycin. The microarray analysis selected mTOR pathway downstream genes consisting of 4 rapamycin up-regulated genes (FABP4, H19, ANXA10, and UPK3A) and 4 rapamycin down-regulated genes (FOXD3, ATP7A, plexin D1, and ADAMTS5). In the TMA, FABP4, and ATP7A were more expressed at T1 and FOXD3 was at Ta. ANXA10 and ADAMTS5 were more expressed in tumors ≤ 3 cm in diameter. In a multivariate Cox regression model, ANXA10 was a significant predictor of recurrence and ATP7A was a significant predictor of progression in non-muscle invasive HG-UC of the bladder. In an ATP7A knock-out model, rapamycin treatment synergistically inhibited cell viability, wound healing, and invasion ability compared to rapamycin only. Activity of the ANXA10 and ATP7A mTOR pathway downstream genes might predict recurrence and progression in non-muscle invasive HG-UC of the bladder. ATP7A knockout overcomes rapamycin cross-talk.

Manipulating the Angiogenesis by Inflammation

There exists a need to develop strategies that promote neovascularization in virtually all tissue engineering and regenerative medicine efforts. While research typically focuses on understanding and exploiting the role of angiogenic factors and vascular cells on new blood vessel formation, the activity of the immune system is being recognized to impact vascular formation and adaptation. This review will provide both an overview of the relationship of angiogenesis and the immune system, and how biomaterials may be designed to promote favorable angiogenesis by interaction between these 2 systems to promote effective vascularization.

NBR1 and KIF14 Downstream of the Mammarian Target of Rapamycin Pathway Predict Recurrence in Nonmuscle Invasive Low Grade Urothelial Carcinoma of the Bladder

PURPOSE: The lack of identified mammalian target of rapamycin (mTOR) pathway downstream genes that overcome cross-talk in nonmuscle invasive low grade (LG)-urothelial carcinoma (UC) of the bladder is a clinical limitation in the use of mTOR inhibitor for the treatment of UC. MATERIALS AND METHODS: Presently, gene expression patterns, gene ontology, and gene clustering by dual (p70S6K and S6K) siRNAs or rapamycin in 253J and TR4 cell lines were investigated by microarray analysis. mTOR/S6K pathway downstream genes suppressed to siRNAs, and rapamycin up-regulated or rapamycin down-regulated genes were identified. The mTOR downstream genes examined using a tissue microarray of 90 nonmuscle invasive LG-UC patients to assess whether any of these genes predicted clinical outcomes. A knockout study evaluated the synergistic effect with rapamycin. RESULTS: In the microarray analysis, mTOR pathway downstream genes selected consisted of 4 rapamycin down-regulated (FOXM1, KIF14, MYBL2, and UHRF1), and 4 rapamycin up-regulated (GPR87, NBR1, VASH1, and PRIMA1). In the tissue microarray, FOXM1, KIF14, and NBR1 were more expressed at T1, and MYBL2, and PRIMA1 were more expressed in tumors exceeding 3 cm. In a multivariate Cox regression model, KIF14 and NBR1 were significant predictors of recurrence in nonmuscle invasive LG-UC of the bladder. In a NBR1 knock out model, rapamycin treatment synergistically inhibited cell viability and colony forming ability compared to rapamycin only. CONCLUSIONS: The results implicate KIF14 and NBR1 as mTOR/S6K pathway downstream genes that predict recurrence in nonmuscle invasive LG-UC of the bladder and demonstrate that NBR1 knockout overcomes rapamycin cross-talk.

Vascularization Methods for Tissue Engineers

Tissue engineering is limited by our inability to adequately vascularize tissues post implantation because all tissue-engineered substitutes (with the exception of cornea and cartilage) require a vascular network to provide the nutrient and oxygen supply needed for their survival. This review gives a brief overview of the processes and factors involved in the vascularization and angiogenesis and summarizes the different strategies to overcome the issue of slow vascularization and angiogenesis in a range of tissue-engineered substitutes. Moreover, we will announce some potential future plans.

Daily Mean Temperature and Urolithiasis Presentation in Six Cities in Korea: Time-Series Analysis

Seasonal variation in urinary stone presentation is well described in the literature. However, previous studies have some limitations. To explore overall cumulative exposure-response and the heterogeneity in the relationships between daily meteorological factors and urolithiasis incidence in 6 major Korean cities, we analyzed data on 687,833 urolithiasis patients from 2009 to 2013 for 6 large cities in Korea: Seoul, Incheon, Daejeon, Gwangju, Daegu, and Busan. Using a time-series design and distributing lag nonlinear methods, we estimated the relative risk (RR) of mean daily urolithiasis incidence (MDUI) associated with mean daily meteorological factors, including the cumulative RR for a 20-day period. The estimated location-specific associations were then pooled using multivariate meta-regression models. A positive association was confirmed between MDUI and mean daily temperature (MDT), and a negative association was shown between MDUI and mean daily relative humidity (MDRH) in all cities. The lag effect was within 5 days. The multivariate Cochran Q test for heterogeneity at MDT was 12.35 (P = 0.136), and the related I2 statistic accounted for 35.2% of the variability. Additionally, the Cochran Q test for heterogeneity and I2 statistic at MDHR were 26.73 (P value = 0.148) and 24.7% of variability in the total group. Association was confirmed between daily temperature, relative humidity and urolithiasis incidence, and the differences in urolithiasis incidence might have been partially attributable to the different frequencies and the ranges in temperature and humidity between cities in Korea.

The Present and Future of the Cancer Microenvironment Bioprinting

Cancer is the tissue complex consisted with heterogeneous cellular compositions, and microenvironmental cues. During the various stages of cancer initiation, development, and metastasis, cell–cell interactions as well as cell-extracellular matrix play major roles. Conventional cancer models both 2-dimensional and 3-dimensional (3D) present numerous limitations, which restrict their use as biomimetic models for drug screening and fundamental cancer biology studies. Recently, bioprinting biofabrication platform enables the creation of high-resolution 3D structures. Moreover this platform has been extensively used to model multiple organs and diseases, and this versatile technique has further found its creation of accurate models that figure out the complexity of the cancer microenvironment. In this review we will focus on cancer biology and limitations with current cancer models and we discuss vascular structures bioprinting that are critical to the construction of complex 3D cancer organoids. We finally conclude with current literature on bioprinting cancer models and propose future perspectives.

Poloxamer 407 Hydrogels for Intravesical Instillation to Mouse Bladder: Gel-Forming Capacity and Retention Performance

PURPOSE: Poloxamer 407 (P407) thermo-sensitive hydrogel formulations were developed to enhance the retention time in the urinary bladder after intravesical instillation. MATERIALS AND METHODS: P407 hydrogels (P407Gels) containing 0.2 w/w% fluorescein isothiocyanate dextran (FD, MW 4 kDa) as a fluorescent probe were prepared by the cold method with different concentrations of the polymer (20, 25, and 30 w/w%). The gel-forming capacities were characterized in terms of gelation temperature (G-Temp), gelation time (G-Time), and gel duration (G-Dur). Homogenous dispersion of the probe throughout the hydrogel was observed by using fluorescence microscopy. The in vitro bladder simulation model was established to evaluate the retention and drug release properties. P407Gels in the solution state were administered to nude mice via urinary instillation, and the in vivo retention behavior of P407Gels was visualized by using an in vivo imaging system (IVIS). RESULTS: P407Gels showed a thermo-reversible phase transition at 4℃ (refrigerated; sol) and 37℃ (body temperature; gel). The G-Temp, G-Time, and G-Dur of FD-free P407Gels were approximately 10℃–20℃, 12–30 seconds, and 12–35 hours, respectively, and were not altered by the addition of FD. Fluorescence imaging showed that FD was spread homogenously in the gelled P407 solution. In a bladder simulation model, even after repeated periodic filling-emptying cycles, the hydrogel formulation displayed excellent retention with continuous release of the probe over 8 hours. The FD release from P407Gels and the erosion of the gel, both of which followed zero-order kinetics, had a linear relationship (r²=0.988). IVIS demonstrated that the intravesical retention time of P407Gels was over 4 hours, which was longer than that of the FD solution ( < 1 hour), even though periodic urination occurred in the mice. CONCLUSIONS: FD release from P407Gels was erosion-controlled. P407Gels represent a promising system to enhance intravesical retention with extended drug delivery.

Recombinant Bacille Calmette–Guérin for Immunotherapy in Nonmuscle Invasive Bladder Cancer

Intravesical instillation of Mycobacterium bovis bacille Calmette–Guérin (BCG) has been used for treating nonmuscle invasive bladder cancer as the forefront of immunotherapy, but BCG is ineffective in approximately 30–40% of cases and disease recurs in up to 50% of patients. Recently BCG is considered an effective vehicle for delivery of antigens due to its unique characteristics, and the genetic control of these mycobacteria is advanced in the search for less toxic and more potent therapeutic agents for bladder cancer immunotherapy. We will discuss current advances in recombinant BCG construction, research, and future directions.