Anti-PD-1 and PD-L1 therapy for bladder cancer: what is on the horizon?

The clinical significance of PD-1 expression in patients with bladder cancer without lymph node metastasis: a comparative study with drained lymph nodes and tumor tissues

OBJECTIVE

In light of the increasing importance of immunotherapy in bladder cancer treatment, this study is aim to investigate the expression and clinical significance of programmed cell surface death-1 (PD-1) in bladder cancer patients without lymph node metastasis, and to compare and analyze the difference of PD-1 in draining lymph nodes and tumor tissues.

METHODS

The expression of PD-1 on T cells and the proportion of positive PD-1 + T cells of IFN-γ and CD105a were detected by flow cytometry, and the correlation between PD-1 expression and clinical parameters was analyzed.

RESULTS

The percentage of PD-1 positive cells in drainage lymph nodes was higher than that in tumor tissues (P < 0.001). PD-1 positive cells accounted for the highest proportion in CD3 + T cells. The proportion of IFN-γ-positive PD-1 + T cells in draining lymph nodes was significantly higher than that in tumor tissues (P < 0.001), while there was no significant difference in CD105a positive PD-1 + T cells between tumor tissues and draining lymph nodes. Pathological grade, tumor size and stage were positively correlated with PD-1 expression level in the lymph nodes.

CONCLUSION

The high expression of PD-1 in patients with bladder cancer without lymph node metastasis, especially in draining lymph nodes, suggests that PD-1 may play a key role in the regulation of tumor immune microenvironment. The correlation between PD-1 and clinical parameters indicates its potential prognostic value. These findings provide important clinical implications for PD-1 targeted therapy, but further prospective studies are needed to determine the application value of PD-1 in therapeutic strategies.

Interferon gamma expression and mortality in unselected cohorts of urothelial bladder cancer patients

Background

The role of interferon gamma (IFN-γ) expression in long-term survival has not been studied in patients with urinary bladder cancer (UBC). IFN-γ expression was characterized among various UBC patient cohorts to assess if IFN-γ status is associated with overall survival (OS).

Methods

A tumor-based IFN-γ gene signature was evaluated among adult UBC patients newly diagnosed between 2004 and 2017 from two hospital systems in New York. Patient cohorts included metastatic (stage IV or progressing to stage IV [MBC]), muscle-invasive (stages T2a to T4a [MIBC]), and non–muscle-invasive (carcinoma in situ or stages 0a, 0is, and I [NMIBC]) disease. Descriptive analyses were conducted comparing IFN-γ signature in the highest tertile to those in the lowest two tertiles.

Results

234 patients with bladder cancer were evaluated (56 MBC, 38 MIBC, and 140 NMIBC). Median OS was only reached in the MIBC cohort for those with an IFN-γ signature in the lowest two tertiles (15.03 months [95% CI, 8.50–50.60]). Those with an IFN-γ signature in the highest tertile had a decreased risk of mortality in all cohorts indicating better survival, but this was statistically significant in only the MIBC cohort (adjusted HR = 0.09 [95% CI, 0.01–0.73]).

Conclusion

IFN-γ signature status was associated with a decreased mortality risk in all cohorts, particularly MIBC, indicating that it may be a prognostic marker of survival in patients with UBC.

AKT Isoforms in the Immune Response in Cancer

AKT is a protein kinase that exists in three isoforms: AKT1, AKT2, and AKT3. Though similar in structure, these isoforms display different effects. AKT is activated downstream of PI3K, and together, this signaling pathway helps regulate cellular processes including cell growth, proliferation, metabolism, survival, and apoptosis. Disruption in these pathways has been associated with disorders including cardiovascular diseases, developmental disorders, inflammatory responses, autoimmune diseases, neurologic disorders, type 2 diabetes, and several cancers. In cancer, deregulation in the PI3K/AKT pathway can be manifested as tumorigenesis, pathological angiogenesis, and metastasis. Increased activity has been correlated with tumor progression and resistance to cancer treatments. Recent studies have suggested that inhibition of the PI3K/AKT pathway plays a significant role in the development, expansion, and proliferation of cells of the immune system. Additionally, AKT has been found to play an important role in differentiating regulatory T cells, activating B cells, and augmenting tumor immunosurveillance. This emphasizes AKT as a potential target for inhibition in cancer therapy. This chapter reviews AKT structure and regulation, its different isoforms, its role in immune cells, and its modulation in oncotherapy.

Immunosuppression Induced by Glutamine Deprivation Occurs via Activating PD-L1 Transcription in Bladder Cancer

Few studies have reported whether nutrients in the tumor microenvironment can regulate the expression of PD-L1. Since tumor cells are often situated in a low-glutamine environment, we investigated PD-L1 expression under glutamine deprivation in bladder cancer cells. PD-L1 expression and the activation of the EGFR/MEK/ERK/c-Jun signaling pathway under glutamine deprivation were investigated by qPCR, Western blot, and immunofluorescence analyses. C-Jun-mediated transcriptional regulation of the PD-L1 gene was assessed by ChIP. PD-L1 expression and activation of the EGFR/MEK/ERK/c-Jun signaling pathway were assessed in T24 cells, TCCSUP cells and BALB/c mice with or without glutamine supplementation. Additionally, the impact of PD-L1 expression under glutamine deprivation on the function of T cells was investigated by ELISA. The expression of PD-L1 and EGFR/MEK/ERK/c-Jun pathway activation were elevated by glutamine deprivation, and c-Jun was enriched in the enhancer region of PD-L1. The expression of PD-L1 was considerably impaired by inhibiting the EGFR/MEK/ERK/c-Jun pathway and was elevated by activating this signaling pathway. In addition, the elevated PD-L1 expression and MEK/ERK/c-Jun signaling pathway activation were reduced by glutamine supplementation in vitro and in vivo. PD-L1 upregulation by glutamine deprivation in bladder cancer cells could reduce IFN-γ production by T cells. The expression of PD-L1 was upregulated under glutamine deprivation through the EGFR/MEK/ERK/c-Jun pathway to impair T cell function.

ASR488, a novel small molecule, activates an mRNA binding protein, CPEB1, and inhibits the growth of bladder cancer

Due to a lack of mechanistic insights, muscle-invasive bladder cancer (MIBC) remains incurable and is one of the most lethal types of cancer in the United States. The present study investigated changes in the molecular signatures of MIBC cells (TCCSUP and HT1376) after treatment with a novel small molecule, ASR488, to gain knowledge of the mechanisms that inhibited MIBC cell growth. ASR488 treatment initiated apoptotic signaling in MIBC cells. Pathway enrichment analysis was used to analyze the changes in function of differentially expressed genes. Gene Ontology analysis, as well as Kyoto Encyclopedia of Genes and Genomes analysis, was also performed. These analyses along with reactome pathway enrichment analyses indicated that the genes upregulated in the ASR488-treated cells are involved in focal adhesion, neurotrophin signaling, p53 signaling, endoplasmic reticulum functioning in terms of protein processing, and pathways related to bladder cancer. The genes downregulated in ASR488-treated MIBC cells were mainly involved in DNA replication, mismatch repair, RNA degradation, nucleotide excision repair and TGFβ signaling (P<0.05). Furthermore, reverse transcription-quantitative PCR analysis revealed an increase in transcripts of the most upregulated genes in ASR 488-treated MIBC cells: CPEB1 (36-fold), IL11 (30-fold), SFN (20.12-fold) and CYP4F11 (15.8-fold). In conclusion, the analysis of biological functions of the most differentially expressed genes revealed possible mechanisms that may be associated with the aggressiveness of MIBC.

Advancements in the clinical management of upper tract urothelial carcinoma

Introduction: Upper tract urothelial carcinoma (UTUC) remains a complex disease to manage given challenges in staging, surgical resection, use of perioperative therapy, and prevention of bladder recurrences. High-level evidence is limited to guide management; however, recent data have shifted treatment paradigms. We intend to review recent evidence on advancements in the clinical management for UTUC.Areas covered: This review summarizes advancements in pre-operative work-up, surgical technique, and the use of intravesical and systemic therapy in both the neoadjuvant and adjuvant settings. Special comment is made on progress in the genomics of UTUC and how that can inform clinical practice.Expert opinion: Advancements in the clinical management of UTUC are most prominently being made in the neoadjuvant chemotherapy setting. Although level I evidence is sparse, data from both single and multi-institutional retrospective studies strongly encourage the use of neoadjuvant chemotherapy especially in high-risk or advanced-stage patients.

The enhanced expression of estrogen-related receptor α in human bladder cancer tissues and the effects of estrogen-related receptor α knockdown on bladder cancer cells

Estrogen-related receptor α (ERRα) belongs to the superfamily of nuclear orphan receptors. However, the role of ERRα in bladder cancer remains unknown. This study examined the expression of ERRα in bladder cancer tissues and explored the molecular mechanisms of ERRα in bladder cancer progression. The expression of ERRα in bladder cancer tissues from 61 patients was determined by immunohistochemistry. We performed quantitative real-time polymerase chain reaction assay to detect the gene expression levels and carried out Western blot assay to measure protein levels. In vitro functional assays, including colony formation, Cell Counting Kit-8, Transwell invasion, and migration assays, were performed to detect bladder cancer cell growth, proliferation, invasion, and migration, respectively. Flow cytometry was used to determine the cell apoptotic rate of bladder cancer cells. Among the 61 detected bladder cancer tissues, 39 bladder cancer tissues showed positive ERRα immunoreactivity. Higher ERRα immunoreactivity score was significantly associated with TNM stage, tumor grade, distant metastasis, and poor survival in patients with bladder cancer. Univariate and multivariate analyses showed that ERRα immunoreactivity was an independent prognostic factor for overall survival in patients with bladder cancer. ERRα was found to be upregulated in bladder cancer cell lines, and knockdown of ERRα suppressed bladder cancer cell growth, proliferation, invasion, and migration; promoted bladder cancer cell apoptosis; and inhibited the epithelial-mesenchymal transition of bladder cancer cells. On the other hand, bladder cancer cell proliferation, invasion, and migration were significantly enhanced after cells were transfected with an ERRα-overexpressing vector. In vivo tumor growth and metastasis assays showed that ERRα knockdown resulted in remarkable inhibition of tumor growth and tumor metastasis in nude mice. Collectively, our results suggest that the enhanced expression of ERRα may play a key role in the development and progression of bladder cancer and ERRα may serve as an important prognostic factor for bladder cancer.

PD-1/PD-L1 immune checkpoint: Potential target for cancer therapy

Recent studies show that cancer cells are sometimes able to evade the host immunity in the tumor microenvironment. Cancer cells can express high levels of immune inhibitory signaling proteins. One of the most critical checkpoint pathways in this system is a tumor-induced immune suppression (immune checkpoint) mediated by the programmed cell death protein 1 (PD-1) and its ligand, programmed death ligand 1 (PD-L1). PD-1 is highly expressed by activated T cells, B cells, dendritic cells, and natural killer cells, whereas PD-L1 is expressed on several types of tumor cells. Many studies have shown that blocking the interaction between PD-1 and PD-L1 enhances the T-cell response and mediates antitumor activity. In this review, we highlight a brief overview of the molecular and biochemical events that are regulated by the PD-1 and PD-L1 interaction in various cancers.

Immune checkpoint inhibitors in urothelial cancer: recent updates and future outlook

Bladder cancer is the sixth most common cancer in the US and most tumors have urothelial (transitional cell) histology. Platinum-based chemotherapy has long been the standard of care in advanced disease, but long-term outcomes have largely remained poor. Since the peak incidence of bladder cancer is in the eighth decade of life and beyond, medical comorbidities may often limit the use of chemotherapy. Immune checkpoint inhibitors with their favorable toxicity profiles and notable antitumor activity have ushered in a new era in the treatment of advanced urothelial cancer (UC) with five agents targeting the PD-1/PD-L1 pathway being recently approved by the US Food and Drug administration. A plethora of clinical trials are ongoing in diverse disease settings, employing agents targeting PD-1/PD-L1 and related immune checkpoint pathways. While reactivating anti-tumor immunity, these agents may lead to a unique constellation of immune-related adverse events, which may warrant discontinuation of therapy and potential use of immunosuppression. Novel combinations with various treatment modalities and optimal sequencing of active therapies are being investigated in prospective clinical trials and retrospective registries. At the era of precision molecular medicine, and since patients do not respond uniformly to these agents, there is a growing need for identification and validation of biomarkers that can accurately predict treatment response and assist in patient selection. This review discusses current updates and future directions of immunotherapy in advanced UC.

In-vitro effect of pembrolizumab on different T regulatory cell subsets

Programmed death-1 (PD-1) and interactions with PD-ligand 1 (PD-L1) play critical roles in the tumour evasion of immune responses through different mechanisms, including inhibition of effector T cell proliferation, reducing cytotoxic activity, induction of apoptosis in tumour-infiltrating T cells and regulatory T cell (T_reg ) expansion. Effective blockade of immune checkpoints can therefore potentially eliminate these detrimental effects. The aim of this study was to investigate the effect of anti-PD-1 antibody, pembrolizumab, on various T_reg subpopulations. Peripheral blood mononuclear cells (PBMC) from healthy donors (HD) and primary breast cancer patients (PBC) were treated in vitro with pembrolizumab, which effectively reduced PD-1 expression in both cohorts. We found that PD-1 was expressed mainly on CD4⁺ CD25⁺ T cells and pembrolizumab had a greater effect on PD-1 expression in CD4⁺ CD25^- T cells, compared to CD4⁺ CD25⁺ cells. In addition, pembrolizumab did not affect the expression levels of T_reg -related markers, including cytotoxic T lymphocyte antigen-4 (CTLA-4), CD15s, latency-associated peptide (LAP) and Ki-67. Moreover, we report that CD15s is expressed mainly on forkhead box P3 (FoxP3)^- Helios⁺ T_reg in HD, but it is expressed on FoxP3⁺ Helios^- T_reg subset in addition to FoxP3^- Helios⁺ T_reg in PBC. Pembrolizumab did not affect the levels of FoxP3^+/- Helios^+/- T_reg subsets in both cohorts. Taken together, our study suggests that pembrolizumab does not affect T_reg or change their phenotype or function but rather blocks signalling via the PD-1/PD-L1 axis in activated T cells.

Immunotherapy in Urothelial Cancer: Recent Results and Future Perspectives

Cytotoxic chemotherapy has been the only systemic treatment of locally advanced and metastatic urothelial carcinoma for decades. Long-term survival remains stagnant around 12-14 months for patients with advanced disease who have progressed on or recurred after receiving first-line platinum-based chemotherapy. Improving clinical outcomes for patients with urothelial carcinoma in all disease settings requires the development of novel treatments, especially for patients who failed on first-line chemotherapy. Since the discovery of intravesical Bacillus-Calmette Guerin (BCG) in the 1970s for non-muscle invasive disease, there have not been any major breakthrough drugs that exploit the immune-sensitivity of bladder cancer until recently. Immune-checkpoint inhibitors targeting the programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) pathways have shown significant anti-tumor activity, tolerable safety profiles and durable, long-term responses in clinical trials. Atezolizumab, avelumab, durvalumab, nivolumab and pembrolizumab are promising PD-1/PD-L1 blockade drugs under investigation that will redefine the standard of care for bladder cancer. CTLA-4 inhibitors are also under investigation in this setting. Atezolizumab, approved in May 2016, and nivolumab, approved in February 2017, are the first Food and Drug Administration (FDA)-approved immune-checkpoint inhibitors in bladder cancer for platinum-pretreated patients based on phase II data. On March 16, 2017, results from the phase III trial KEYNOTE-045 demonstrated that survival was significantly longer in patients treated with pembrolizumab when compared with the standard second-line chemotherapy. Research into biomarkers such as PD-L1 expression, messenger RNA subtype, mutational and neoantigen load and gene signature expression will be crucial to determining why some patients respond to immunotherapy and others do not. This review article describes the advances in immunotherapy since the development of BCG, presents results from clinical trials investigating immune-checkpoint inhibitors and discusses biomarkers and prognostic factors associated with response to these new drugs.

Survival after Metastasectomy for Metastatic Urothelial Carcinoma: A Systematic Review and Meta-Analysis

Background: Cisplatin-based combination chemotherapy is standard treatment for metastatic urothelial carcinoma; however, the vast majority of patients experience disease progression. As systemic therapy alone is rarely curative for the treatment of metastatic urothelial cancer, not only are new therapies needed but also refinement of general treatment principles. Herein, we conducted a systematic review and meta-analysis to explore the role of metastasectomy in metastatic urothelial carcinoma.

Methods: We conducted a systematic review of the literature regarding local treatment for metastatic urothelial carcinoma. An online electronic search of the PubMed/MEDLINE and EMBASE databases was performed to identify peer-reviewed articles. All procedures were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Information was then extracted including number of patients, gender, the site of the primary urothelial tumor, site of metastasis, chemotherapy before or after metastasectomy, overall survival (OS), and disease specific survival (DSS) after metastasectomy. A meta-analysis was performed with those studies with sufficient survival data to obtain pooled overall survival. The article quality was assessed using the Cochrane Handbook “risk of bias” tool.

Results: Seventeen out of 3963 articles were eligible for review between 1990–2015, including a total of 412 patients. The mean time to recurrence after metastasectomy was 14.25 months. The overall survival from time of metastasectomy ranged from 2 to 60 months. Pooled analyses of studies reported survival data revealed an improved overall survival for patients treated with metastasectomy compared with non-surgical treatment of metastatic lesions (HR 0.63; 95% CI, 0.49–0.81). All, except for three studies, were retrospective and non-randomized, leading to a high risk of bias associated with patient selection, patient attrition, and reporting. Such high potential of selection bias may lead to higher OS than expected. Additionally, treatment and outcome details reported across studies was highly variable.

Conclusions: Limited conclusions can be drawn from the available literature exploring the role of metastasectomy in the management of metastatic urothelial cancer due to lack of uniform reporting elements and multiple sources of bias particularly related to a lack of prospective randomized trials. As a subset of patients treated with metastasectomy achieve durable disease control, this approach may be considered for select patients.

A review on the evolution of PD-1/PD-L1 immunotherapy for bladder cancer: The future is now

The treatment of bladder cancer has evolved over time to encompass not only the traditional modalities of chemotherapy and surgery, but has been particularly impacted by the use of immunotherapy. The first immunotherapy was the live, attenuated bacterial Bacillus Calmette-Guérin vaccine, which has been the standard of care non-muscle-invasive bladder cancer since 1990. Modern immunotherapy has focused on inhibitors of checkpoint proteins, which are molecules that impede immune function, thereby allowing tumor cells to grow and proliferate unregulated. Several checkpoint targets (programmed death ligand-1 [PD-L1] programmed cell death protien-1 [PD-1], and cytotoxic T-lymphocyte associated protein 4 [CTLA4]) have received the most attention in the treatment of bladder cancer, and have inhibitor agents either approved or in late-stage development. This review describes the most recent data on agents that inhibit PD-L1, found on the surface of tumor cells, and PD-1 found on activated T and B cells and macrophages. Atezolizumab is the only member of this class currently approved for the treatment of bladder cancer, but nivolumab, pembrolizumab, durvalumab, and avelumab all have positive results for this indication, and approvals are anticipated in the near future. The checkpoint inhibitors offer an effective alternative for patients for whom previously there were few options for durable responses, including those who are ineligible for cisplatin-based regimens or who are at risk of significant toxicity. Research is ongoing to further categorize responses, define ideal patient populations, and investigate combinations of checkpoint inhibitors to address multiple pathways in immune system functioning.

Non-muscle-invasive bladder cancer: Intravesical treatments beyond Bacille Calmette-Guérin

An unmet need exists for patients with high-risk non-muscle-invasive bladder cancer for whom bacille Calmette-Guérin (BCG) has failed and who seek further bladder-sparing approaches. This shortcoming poses difficult management dilemmas. This review explores previously investigated first-line intravesical therapies and discusses emerging second-line treatments for the heterogeneous group of patients for whom BCG has failed. The myriad of recently published and ongoing trials assessing novel salvage intravesical treatments offer promise to patients who both seek an effective cure and want to avoid radical surgery. However, these trials must carefully be contextualized by specific patient, tumor, and recurrence characteristics. As data continue to accumulate, there will potentially be a role for these agents as second-line or even first-line intravesical therapies. Cancer 2017;123:390-400. © 2016 American Cancer Society.

Immunotherapy in genitourinary malignancies

PURPOSE OF REVIEW

Active investigation suggests immune checkpoint inhibitor therapy and therapeutic cancer vaccines provide clinical benefit for genitourinary malignancies including prostate cancer, renal cell carcinoma, and bladder cancer. Recent developments in the utility of immune checkpoint inhibitor and vaccine therapy for the management of genitourinary malignancies are highlighted in this review.

RECENT FINDINGS

Dramatic responses to checkpoint inhibitor therapy have been demonstrated in renal cell carcinoma and bladder cancer with recent Food and Drug Administration approvals in both indications. No benefit to checkpoint inhibitor therapy has yet been shown for the management of prostate cancer. Therapeutic cancer vaccines have also shown benefit in the treatment of genitourinary malignancies, specifically in the treatment of prostate cancer. Despite advances in these therapeutic modalities, benefit is limited to a subset of patients.

SUMMARY

Current evidence supports the use of immune checkpoint inhibitor therapy and therapeutic cancer vaccines for the management of genitourinary malignancies. Further development of biomarkers for predicting response and study of combination therapy is required to achieve optimal efficacy with these therapeutic interventions.

Systemic therapy for metastatic bladder cancer in 2016 and beyond

Metastatic urothelial cancer is generally associated with poor outcomes. In the first-line setting, platinum-based chemotherapy is the standard of care but resistance rapidly develops and the vast majority of patients ultimately experience disease progression. Despite several decades of clinical drug development focused on the treatment of platinum-resistant metastatic urothelial cancer, as of late 2015 there are no standard therapies approved by the US FDA in this setting. However, preliminary results from a series of recent trials exploring innovative approaches forecast a 'sea change' in the management of this difficult to treat malignancy. Herein, we review new approaches for the management of patients with metastatic urothelial cancer focused on three key therapeutic target areas: recurrent somatic alterations, the tumor neovasculature and tumor-associated immune escape.