Combination of BCG and interferon intravesical immunotherapy: an update

Non-Muscular Invasive Bladder Cancer: Re-envisioning Therapeutic Journey from Traditional to Regenerative Interventions

Non-muscular invasive bladder cancer (NMIBC) is one of the most common cancer and major cause of economical and health burden in developed countries. Progression of NMIBC has been characterized as low-grade (Ta) and high grade (carcinoma in situ and T1). The current surgical intervention for NMIBC includes transurethral resection of bladder tumor; however, its recurrence still remains a challenge. The BCG-based immunotherapy is much effective against low-grade NMIBC. BCG increases the influx of T cells at bladder cancer site and inhibits proliferation of bladder cancer cells. The chemotherapy is another traditional approach to address NMIBC by supplementing BCG. Notwithstanding, these current therapeutic measures possess limited efficacy in controlling NMIBC, and do not provide comprehensive long-term relief. Hence, biomaterials and scaffolds seem an effective medium to deliver therapeutic agents for restructuring bladder post-treatment. The regenerative therapies such as stem cells and PRP have also been explored for possible solution to NMIBC. Based on above-mentioned approaches, we have comprehensively analyzed therapeutic journey from traditional to regenerative interventions for the treatment of NMIBC.

Gmcsf and Ifnα gene therapy improves the response to BCG immunotherapy in a murine model of bladder cancer

Aim: To develop a strategy to improve response to bacillus Calmette-Gueri (BCG) using cytokine gene therapy (Gmcsf + Ifnα). Materials & methods: MB49-PSA tumor-bearing C57BL/6N mice were assigned into four groups: control; Gmcsf + Ifnα therapy; BCG therapy or combined therapy (Gmcsf + Ifnα and BCG). In schedule 1, cytokine gene therapy was delivered before BCG therapy (eight instillations). In schedule 2, cytokine gene and BCG therapy were instilled alternatively (eight instillations). Tumors were analyzed by immunohistochemistry and mRNA analysis and urinary immune cells by flow cytometry. Results: Combined therapy in schedule 2 reduced tumor growth, increased immune cell recruitment and was associated with reduced inflammation when compared with BCG therapy. Conclusion: Alternating cytokine gene delivery with BCG therapy modulates the tumor environment increasing receptivity to BCG.

socs7, a target gene of microRNA-145, regulates interferon-β induction through STAT3 nuclear translocation in bladder cancer cells

We recently reported that microRNA (miR)-145 is downregulated and induces apoptosis in human bladder cancer cells. Also, it is suggested that the ectopic expression of miR-145 induces apoptosis with the induction of TRAIL expression in several cancer cells. Here, we demonstrated a novel mechanism of apoptosis induction by miR-145 in bladder cancer cells. Exogenous miR-145 in T24 and NKB1 cells markedly increased the expression levels of interferon (IFN)-β, 2′–5′-oligoadenylate synthetase 1, which lies upstream of 2′–5′ oligoadenylates/RNase L system, and TRAIL, and induced apparent caspase-dependent apoptosis that was suppressed by cotreatment with a pan-caspase inhibitor; moreover, these expression levels were reduced by cotreatment with an miR-145 inhibitor. The apoptosis did not depend on Toll-like receptor 3 (TLR3) expression, because TLR3-silencing failed to inhibit IFN-β induction by miR-145. Then, we focused on the suppressor of cytokine signaling 7 (socs7), whose expression level was upregulated in bladder cancer cells compared with its level in normal human urothelial cells, as a putative target gene involved in IFN-β induction by miR-145. Expectedly, exogenous miR-145 decreased the expression level of SOCS7, and socs7-silencing enhanced IFN-β induction by transfection with a TLR3 ligand, polyinosinic acid-polycytidylic acid (PIC). The results of a luciferase reporter assay revealed that miR-145 targeted socs7. In addition, socs7-silencing significantly decreased the level of p-Akt and suppressed the growth of T24 cells. Furthermore, exogenous miR-145 or socs7-silencing promoted nuclear translocation of STAT3. In conclusion, the machinery of IFN-β induction through the regulation of SOCS7 by miR-145 was closely associated with the induction of apoptosis. Moreover, exogenous miR-145 promoted IFN-β induction by targeting socs7, which resulted in the nuclear translocation of STAT3. Additionally, our data indicate that SOCS7 functioned as an oncogene, the finding that revealed a novel mechanism of carcinogenesis in bladder cancer cells.

Synergistic Cytotoxic Effects of Ganoderma lucidum and Bacillus Calmette Guérin on Premalignant Urothelial HUC-PC Cells and Its Regulation on Proinflammatory Cytokine Secretion

Bacillus Calmette-Guérin (BCG) is conventionally used as an adjuvant immunotherapy to reduce the recurrence of bladder cancer. To address the issues of efficacy and safety, an ethanol extract of Ganoderma lucidum (GLe) was evaluated for its interaction with BCG. In a model of premalignant human uroepithelial cells (HUC-PC), GLe exerted immediate cytotoxic effects while BCG showed a delayed response, given that both were immunological active in inducing the secretion of interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1 (MCP-1). Synergistic cytotoxic effects were observed when cells were either coincubated with both drugs or firstly preincubated with GLe. Synergism between GLe and BCG was demonstrated to achieve a complete cytostasis in 24 hours, and such effects were progressed in the subsequent 5 days. However, the pretreatment of GLe resulted in suppression of IL-6, IL-8, and MCP-1 secretions without affecting the cytotoxicity. Given that numerous proinflammatory cytokines are associated with the high side effects toll of BCG, results herein suggested the potential implications of GL to supplement the BCG immunotherapy in bladder cancer, for better efficacy and reducing side effects.

Urothelial carcinoma of the bladder: definition, treatment and future efforts

The identification of patients with high-risk bladder cancer is important for the timely and appropriate treatment of this lethal disease. The understanding of the natural history of bladder cancer has improved; however, the criteria used to define high-risk disease and the relevant treatment strategies have remained the same for the past several decades, despite multiple large, randomized, prospective clinical trials that have evaluated the use of intravesical, surgical and systemic therapies. The genetic signature of high-risk bladder cancer has been a focus of investigation and has led to the discovery of potential molecular targets for disease identification, risk stratification and therapy. These advances, combined with a comprehensive risk assessment profile that incorporates available pathological and clinical characteristics, might improve the diagnosis and treatment of patients with bladder cancer.

Immunotherapy for urothelial carcinoma: current status and perspectives

Intravesical instillation of bacillus Calmette Guérin (BCG) for the treatment of urothelial carcinoma (UC) of the bladder is based on the BCG-induced immune response, which eradicates and prevents bladder cancer. The results of recent studies have suggested that not only major histocompatibility complex (MHC)-nonrestricted immune cells such as natural killer cells, macrophages, neutrophils, etc., but also MHC-restricted CD8⁺ T cells play an important role and are one of the main effectors in this therapy. Better understanding of the mechanism of BCG immunotherapy supports the idea that active immunotherapy through its augmented T cell response can have great potential for the treatment of advanced UC. In this review, progress in immunotherapy for UC is discussed based on data from basic, translational and clinical studies. We also review the escape mechanism of cancer cells from the immune system, and down-regulation of MHC class I molecules.

Contemporary management of patients with high-risk non-muscle-invasive bladder cancer who fail intravesical BCG therapy

It is advocated that patients with high-risk non-muscle-invasive bladder cancer (NMIBC) receive an adjuvant course of intravesical Bacille Calmette-Guerin (BCG) as first-line treatment. However, a substantial proportion of patients will 'fail' BCG, either early with persistent (refractory) disease or recur late after a long disease-free interval (relapsing). Guideline recommendation in the 'refractory' setting is radical cystectomy, but there are situations when extirpative surgery is not feasible due to competing co-morbidity, a patient's desire for bladder preservation or reluctance to undergo surgery. In this review, we discuss the contemporary management of NMIBC in patients who have failed prior BCG and are not suitable for radical surgery and highlight the potential options available. These options can be categorised as immunotherapy, chemotherapy, device-assisted therapy and combination therapy. However, the current data are still inadequate to formulate definitive recommendations, and data from ongoing trials and maturing studies will give us an insight into whether there is a realistic efficacious second-line treatment for patients who fail intravesical BCG but are not candidates for definitive surgery.

Investigational therapies for non-muscle invasive bladder cancer

IMPORTANCE OF THE FIELD

Bacillus Calmette-Guérin (BCG) is currently the most effective adjuvant intravesical agent at preventing disease recurrence and the only therapy shown to inhibit disease progression in non-muscle invasive bladder cancer (NMIBC). However, recurrence rates as high as 30% and significant local/systemic toxicity have resulted in an increased interest in the use of alternative intravesical agents.

AREAS COVERED IN THE REVIEW

Our aim is to discuss recent clinical trial evidence utilizing novel intravesical agents for treatment of NMIBC. A systematic literature review was performed via the National Center for Biotechnology Information databases to identify pertinent studies from 2000-2009.

WHAT THE READER WILL GAIN

A durable response has been demonstrated with alternative agents in patients refractory to or intolerant of BCG. This review compares the merits and shortcomings of these emerging agents, focusing on clinical trial safety and efficacy results.

TAKE HOME MESSAGE

Despite recent enthusiasm for novel agents, radical cystectomy remains the treatment of choice for patients with NMIBC who have failed intravesical therapy. However, evidence is accumulating that novel agents provide an efficacious alternative in patients refractory or intolerable to BCG or unfit for cystectomy. Further randomized prospective data are required to demonstrate a recurrence- and progression-free benefit compared with BCG.

Emerging targeted therapies for bladder cancer: a disease waiting for a drug

Urothelial cell carcinoma is the fifth most common cancer and the costliest to treat. This is largely because of all new cases, about 70% present as superficial disease and this while rarely fatal, tends to recur, requiring long-term follow-up and repeat interventions. The standard of care, intravesical chemo- and immunotherapy, while effective, is associated with a considerable side-effect profile and approximately 30% of patients either fail to respond to treatment or suffer recurrent disease within 5 years. Muscle-invasive bladder cancer is life threatening, showing modest chemosensitivity, and usually requires radical cystectomy. Although bladder cancer is fairly well-genetically characterized, clinical trials with molecularly targeted agents have, in comparison to other solid tumors such as lung, breast and prostate, been few in number and largely unsuccessful, with no new agents being registered in the last 20 years. Hence, bladder cancer represents a considerable opportunity and challenge for molecularly targeted therapy.

New therapies for non-muscle-invasive bladder cancer

The treatment of non-muscle-invasive bladder cancer (NMIBC) remains a challenge owing to its increased tendency to recur and the possibility of progression to potentially dangerous muscle-invasive disease. Treatment outcomes by current therapeutic modalities are still not optimal. In recent years, there have been a number of substantive advances in the therapeutic options for the management of NMIBC. New chemotherapeutic drugs have been introduced, along with efforts made to improve the efficacy of existing agents and enhance delivery of agents to the bladder. There is also a growing trend toward combination of agents and multimodal therapy. Also of considerable interest are the investigation of newer approaches such as gene therapy, chemoenhancement and newer forms of immunotherapy. Here, we review the recent pre-clinical and clinical developments in the treatment of NMIBC, described in the broad categories of immunotherapy, chemotherapeutic agents, improved or device-assisted agent delivery and gene therapy.