Editor's Pick: A Short Overview on Therapeutic Biomarkers for Muscle Invasive Bladder Carcinoma - European Medical Journal

Editor’s Pick: A Short Overview on Therapeutic Biomarkers for Muscle Invasive Bladder Carcinoma

6 Mins
Urology
Download PDF
Authors:
*Anika Sadaf,1 Khondaker Md Ismail2
Disclosure:

The authors have disclosed no conflicts of interest.

Received:
28.02.22
Accepted:
10.01.23
Citation:
EMJ Urol. ; DOI/10.33590/emjurol/10307268. https://doi.org/10.33590/emjurol/10307268.
Keywords:
Advanced urothelial carcinoma (UC), chemotherapy, molecular biomarker, proto-oncogene, tumour suppressor gene.

Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.

Abstract

Urothelial carcinoma (UC) is the second most common urologic malignancy after prostatic adenocarcinoma. UC comprises more than 90% of urinary bladder tumours. The intense research involving the different molecular aspects of bladder malignancies offers potential opportunities to improve understanding of bladder cancer biology; helps to identify disease earlier; and improves prediction of outcomes or helps targeted therapy.

This review highlights the general concepts of the molecular features: molecular pathways for bladder carcinomas and molecular biomarkers for potential target for treatment of UC of the bladder. This discussion could improve the understating of pathogenesis as well as will provide new therapeutic modules, e.g., targeted therapy.

This article is a review of bladder cancer genetics, focusing on molecular changes and their significance in the pathogenesis and progression of muscle invasive UC. Also, the relevant genetic biomarkers and their products, and new therapeutic targets and agents that are being developed are presented here.

Key Points

1. Molecular technologies have facilitated the identification of bladder cancer genetics and molecular changes, and their significance in the pathogenesis and progression of muscle invasive urothelial carcinoma. The relevant genetic biomarkers and their products, new therapeutic targets and agents, and potential future perspectives are discussed in this article.
2. Biomarkers such as serum vascular endothelial growth factor, circulating tumour cells, and defects in DNA damage repair genes can predict responses to cisplatin-based neoadjuvant chemotherapy in many patients with muscle invasive bladder cancer.
3. High tumour mutational burden has been associated with response to immune checkpoint inhibitors in a metastatic bladder cancer setting. Immune checkpoint inhibitors in the neoadjuvant setting, using pembrolizumab or atezolizumab before radical cystectomy in patients with muscle invasive bladder cancer, is an approach that is in continuous evolution and needs frequent updates.

INTRODUCTION

Bladder cancer (BC) is the fourth most common malignancy in males and shows high prevalence and mortality rates worldwide despite improvements in its management.1,2 Although non-muscle invasive BC is the commonest type, 25–30% of bladder tumours are muscle invasive (MIBC) at the time of diagnosis, and these patients often have a poor prognosis despite traditional treatments.3 Therefore, both in treatment and follow-up, BC remains a challenging disease for urologists. Identifying promising molecular markers and improving the clinical strategies for managing BC have become crucial.4

Histopathological and molecular studies indicate that urothelial carcinomas (UC) follow two different molecular pathways with distinct biological behaviour. UC has two subtypes. One is the papillary, low-grade, non-invasive UC (70%), arising from urothelial papilloma or hyperplasia and have high recurrence rate. The second subtype is muscle invasive UC (Stages pT2–pT4) that often develops metastases, and 5-year survival rate is <50%. They usually arise through the sequences of events: normal to dysplasia to carcinoma in situ to invasive tumours.5,6 Previously, management of UC was based on conventional histologic parameters. However, similar UCs may show different response to treatment, which is the evidence of molecular heterogeneity among histologically similar tumours. Intensive molecular research over the last few decades have provided great insight into the biology of UC. Molecular technologies have facilitated the identification of molecular pathways and predicted outcomes of BC, thereby potentially improving life expectancy of patients.7,8

MOLECULAR BASIS OF CARCINOGENESIS IN ADVANCED BLADDER UROTHELIAL CARCINOMA

The molecular basis of carcinogenesis in advanced bladder UC includes: self-sufficiency in growth (epidermal growth factor receptor [EGFR] and hepatocyte growth factor); insensitivity to inhibition of growth (p RB, p53, and p27); evasion of apoptosis (p53, Fas, cluster of differentiation 40, and B cell lymphoma 2 [Bcl-2]); unlimited ability to replicate (telomerase increase); angiogenesis (vascular endothelial growth factor [VEGF], cyclooxygenase-2 [COX-2], platelet-derived growth factor, IL-8, and basic fibroblast growth factor); thrombospondin, angiostatin, and endostatin; tissue invasion (matrix metalloproteinase tissue inhibitor of metalloproteinase); and metastasis (P-cadherin, E-cadherin, β-catenin, and cluster of differentiation 44).

NEW ERA OF MOLECULAR MARKERS AND INVASIVE BLADDER CARCINOMA

Over the last few decades, cisplatin-based chemotherapy has been practiced as the first-line treatment in advanced UC; no potential progress has been evident in the treatment of MIBC. As cisplatin-based chemotherapy is effective in only 30–40% cases of BC, novel therapeutic approaches are crying demand for this lethal cancer.9

New insights into the molecular pathology of BC have focused on some promising therapeutic targets.10 The phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway, the mitogen-activated protein kinase pathway, CDKN2A/CDK4/CCND1 and receptor tyrosine kinases/Ras pathways (including ERBB2 [HER2], ERBB3, and FGFR3, as well as chromatin regulatory genes) have critical role in bladder tumourigenesis, specifically in high-grade urothelial carcinomas.11,12 So, further exploration of this pathways in BC is important for prognostic information and targeted therapy.

In the following discussion, UC related proto-oncogenes and tumour suppressor genes and growth factors are emphasised with their therapeutic implication in invasive BC.

TUMOUR SUPPRESSOR GENES

p53

Wild-type p53 promotes anti-cancer activity by inducing cell cycle arrest, apoptosis in response to DNA damage, genomic stability, and inhibition of angiogenesis. On the other hand, the mutant p53 loses its anti-tumour effect and induces abnormal gene expression, thereby leading to tumour progression.13,14 A Phase II clinical trial on the ubiquitin–proteosome proteolytic pathway that regulates metabolism p53 has been conducted by using proteosome inhibitor (bortezomib) in 18 patients with advanced or metastatic UC, and found no effect on its own

Gene therapy by adenoviral vectors on pre-clinical BC cell lines are also on trial to transduce cells for producing the p53 protein; and the preliminary results are promising.15,16

Rb

The Rb gene is responsible for progression of UC. The incidence of Rb mutations is higher in invasive UC (about 37%). There is evidence to support the association between the loss of Rb gene expression and progression of UC in patients with muscle invasive cancer. Pre-clinical trials on adenoviral vectors have also produced optimistic results when investigating transduction of BC cell lines with the Rb gene.17,18

PROTO-ONCOGENES

B cell lymphoma 2

Mutations of proto-oncogenes result in the over-expression of gene product or altered proteins.19 Bcl-2 is a key protein regulator for the cell cycle and apoptotic pathway. Apoptosis is an essential mechanism for radio- and chemotherapy induced cell death. Overexpression of Bcl-2 alters the sensitivity of chemo- and radiotherapy to tumour cells.20,21 Pollack et al.22 analysed 107 patients where only 16 cases were upstaged and 75% (12 cases) of these tested Bcl-2 positive by immunohistochemical analysis. Yet only 24% of those that exhibited Bcl-2 overexpression were upstaged. So, they hypothesised that Bcl-2 overexpression was associated with impaired radiation response in patients with invasive BC treated with pre-operative radiotherapy.22 In BC cell lines, antisense oligonucleotides (oblimersen) down-regulate Bcl-2 expression and enhance apoptosis in response to chemotherapy. The oblimersen Bcl-2 antisense therapy represents a promising new apoptosis-modulating strategy and pre-clinical trials support this synergistic therapeutic role for oblimersen with cytotoxic drugs.23,24

C-erb B-1 and C-erb B-2

C-erb B-1 and C-erb B-2 oncogenes encode transmembrane proteins and EGFR and HER2, respectively.25 Identification of predictive biomarkers of EGFR targeted therapy can improve the development of anti-EGFR drugs. Rebouissou et al.26 reported EGFR as a potential therapeutic target for MIBC displaying basal-like phenotype. Another EGFR inhibitor, gefitinib had shown promising result during clinical trials in combination with gemcitabine and cisplatin.27 Some Phase II/III trails on dual inhibitors of ErbB-1 and ErbB-2 receptor tyrosine kinases such as lapatinib were proven to be well tolerated in patients with EGFR and/or HER2 overexpressing MIBC.28,29

A standardised trail on 1,005 patients with MIBC by Laé et al.30 showed that approximately 5% of MIBC had HER2 gene amplification. There are several ongoing clinical trials to identify potential candidates for targeted therapy in MIBC patients with HER2 overexpression. A Phase II trial has examined the response of trastuzumab (monoclonal antibody) in 59 patients with muscle invasive HER2 over-expressive BC and documented 73% response rate.31 A Phase II trial of 44 cases of HER2 positive UC showed a 70% response when evaluating trastuzumab in combination with chemotherapeutic drugs such as paclitaxel, gemcitabine, and, carboplatin.32

PI3K/Akt/mTOR Pathway

The mTOR pathway plays a vital role in the development UC. This pathway includes upstream activators such as PI3K and Akt, negative regulators such as tuberous sclerosis 1 and 2, and downstream effectors such as p70 S6 kinase and eukaryotic initiation factor 4E. Due to its basic role in tumour growth, researchers have focused on developing targeted therapy on the mTOR.33 Based on durable response in other tumours and pre-clinical trails in BC cell lines, buparlisib (PI3K blockade) is being investigated as a second-line treatment for patients with advanced UC.34 Again, NVP-BEZ235 (dual PI3K/mTOR inhibitors) showed significant anti-tumour effect on cisplatin-resistant BC cells lines, but it can activate mitogen-activated protein kinase/extracellular signal-regulated kinase pathway.35 A Phase II study on 45 patients evaluated the role of everolimus (mTOR inhibitor) in advanced UC, but effective response was documented in only three cases.36

ANGIOGENIC-ANTIANGIOGENIC FACTORS

Vascular Endothelial Growth Factor

VEGF proteins and gene expressions are detected at high levels in high-grade and muscle invasive UCs and are associated with poor survival.37,38 Again, some studies showed that VEGF expression was significantly higher in non-MIBC compared to MIBC as the rate of tumour growth is higher at the early stage of the disease.39,40 So, the inhibition of VEGF transcripts significantly reduces the proliferation rate of the bladder cancer cells41 and blockade of VEGF receptor reduces growth and invasion of bladder cancer cells.42,43 Bevacizumab (VEGF antibody) and ramucirumab (VEGFR2 antibody), used in combination with chemotherapy, showed promising result in Phase II clinical studies of advanced UC. There are multiple ongoing Phase II trials with other agents targeting VEGF receptors, including sunitinib, sorafenib, and pazopanib.44,45

Cyclooxygenase-2

The selective COX-2 inhibitor celecoxib has chemo-protective activity against various cancers, including BC. It inhibits the proliferation, migration, invasion, and epithelial-to-mesenchymal transition of BC cells.46 Epidemiological and pre-clinical evidence suggest that COX-2 inhibitors are promising target for BC. COX-2 expression in the UC is associated with a high grade and an advanced stage, and is an independent predictor of disease progression and survival. However, future trials on COX-2 inhibitors should be tested as a standardised therapy to improve the effectiveness of drugs.47

Thrombospondin-1

Down-regulation of thrombospondin-1 (TSP-1) expression is independently associated with cancer recurrence and mortality. Loss of TSP-1 expression is associated with alterations in other cell cycle regulators such as p21, p53, and p27 expression.48 The newer molecular agents such as the TSP analogue (ABT-510) and TSP-1 mimetics (D-isoleucyl enantiomer TSP-1 heptapeptide) are in Phase II clinical trials, which have been shown to reduce micro-vessel density and increase apoptosis in bladder tumours.49,50

The genes, proteins, and molecules with the potential to alter the muscle invasive UCs with their therapeutic targets are shown in Table 1.

Table 1: Summary of genes and molecules with potential therapeutic targets.
Bcl-2: B cell lymphoma 2; COX-2: cyclooxygenase-2; mTOR: mammalian target of rapamycin; PI3K: phosphoinositide 3-kinase; TSP-1: thrombospondin-1; VEGF: vascular endothelial growth factor.

Some key messages should be pointed out. For instance, many predictive biomarkers were investigated (e.g., serum VEGF, circulating tumour cells, and defects in DNA damage repair genes, which involve ERCC2, ATM, RB1, and FANCC). These biomarkers can predict responses to cisplatin-based neoadjuvant chemotherapy in many patients with MIBC.

In addition, high tumour mutational burden has been associated with response to immune checkpoint inhibitors in metastatic BC. Studies evaluating immune checkpoint inhibitors in the neoadjuvant setting, using pembrolizumab or atezolizumab before radical cystectomy in patients with MIBC (e.g., PURE-01 study and ABACUS study)51 have shown some conflicting results, and, thus, more research is needed. Moreover, programmed death-ligand 1 expression by immunohistochemistry and high tumour mutational burden has demonstrated predictive value in some MIBC settings, but additional studies are merited to explore this topic.

Overall, prognostic and predictive molecular biomarkers will present important adjuncts to current clinical and pathological data. However, large-scale Phase III randomised clinical trials with long-term follow-up are necessary to further investigate this area.

CONCLUSION

Urologists are still treating BC depending on disease stage. Resection of tumour, intravesical mitomycin C, and Bacillus Calmette–Guérin immunotherapy, followed by surveillance are treatment of choice for non-MIBCs. Muscle invasive carcinomas (stage T2) are treated with either radical cystectomy followed by radiotherapy, while metastatic diseases are treated by adjuvant or neoadjuvant chemotherapy. These treatment protocols have improved the disease-free survival; however, overall survival has remained unchanged. Therefore, establishing new treatment regimens for MIBC for better management and overall survival is a crying need. Recent and on-going randomised control trials on molecular biomarkers in muscle invasive disease will be needed to evaluate the precise role and ideal regimen for MIBC.

References
Siegel RL et al. Cancer statistics, 2019. CA Cancer J Clin. 2019;69(1):7-34. Antoni S et al. Bladder cancer incidence and mortality: a global overview and recent trends. Eur Urol. 2017;71(1):96-108. Alfred Witjes J et al. Updated 2016 EAU guidelines on muscle-invasive and metastatic bladder cancer. Eur Urol. 2017;71(3):462-75. Yucai W et al. P4HB: a novel diagnostic and prognostic biomarker for bladder carcinoma. Oncol Lett. 2021;21(2):95. Yousef PG, Gabril MY. An update on the molecular pathology of urinary bladder tumors. Pathol Res Pract. 2018;214(1):1-8. Sanli O et al. Bladder cancer. Nat Rev Dis Primers. 2017;3:17022. Ashish M et al.; International Consultation on Urologic Disease-European Association of Urology Consultation on Bladder Cancer 2012. ICUD-EAU International Consultation on Bladder Cancer 2012: screening, diagnosis, and molecular markers. Eur Urol. 2013;63(1):4-15. Soria F et al. Molecular markers in bladder cancer. World J Urol. 2019;37(1):31-40. Shah JB et al. New strategies in muscle-invasive bladder cancer: on the road to personalized medicine. Clin Cancer Res. 2011;17(9):2608-12. McConkey DJ et al. New insights into subtypes of invasive bladder cancer: considerations of the clinician. Eur Urol. 2014;66(4):609-10. Carneiro BA et al. Emerging therapeutic targets in bladder cancer. Cancer Treat Rev. 2015;41(2):170-8. Iyer G et al. Prevalence and co-occurrence of actionable genomic alterations in high-grade bladder cancer. J Clin Oncol. 2013;31(25):3133-40. Wasylishen AR, Lozano G. Attenuating the p53 pathway in human cancers: many means to the same end. Cold Spring Harb Perspect Med. 2016;6(8):26-36. Zheng L et al. Significant expression of chk1 and p53 in bladder urothelial carcinoma as potential therapeutic targets and prognosis. Oncol Lett. 2018;15(1):568-74. Sridhar SS et al. Phase II study of bortezomibin advanced or metastatic urothelial cancer. A trial of the Princess Margaret Hospital (PMH) phase II consortium. J Clin Oncol. 2005;23(Suppl 16):4677. Kamat AM et al. The proteasome inhibitor bortezomib synergizes with gemcitabine to block the growth of human 253JB-V bladder tumors in vivo. Mol Cancer Ther. 2004;3(3):279-90. Cordon-Cardo C. Mutations of cell cycle regulators. Biological and clinical implications for human neoplasia. Am J Pathol. 1995;147(3):545-60. Xu HJ et al. Enhanced tumor suppressor gene therapy via replication-deficient adenovirus vectors expressing an N-terminal truncated retinoblastoma protein. Cancer Res. 1996;56(10):2245-9. Ahmed HU et al. Bladder carcinoma: understanding advanced and metastatic disease with potential molecular therapeutic targets. Expert Rev Anticancer Ther. 2005;5(6):1011-22. Rödel C et al. Apoptosis, p53, bcl2, and Ki67 in invasive bladder carcinoma: possible predictors for response to radio chemotherapy and successful bladder preservation. Int J Radiat Oncol Biol Phys. 2000;46(5):1213-21. Dole M et al. Bcl-2 inhibits chemo- therapy-induced apoptosis in neuroblastoma. Cancer Res. 1994;54(12):3253-9. Pollack A et al. Abnormal bcl-2 and pRb expression are independent correlates of radiation response in muscle-invasive bladder cancer. Clin Cancer Res. 1997;3(10):1823-9. Hussain SA et al. BCL2 expression predicts survival in patients receiving synchronous chemoradiotherapy in advanced transitional cell carcinoma of the bladder. Oncol Rep. 2003;10(3):571-6. Klasa RJ et al. Oblimersen Bcl-2 antisense: facilitating apoptosis in anticancer treatment. Antisense Nucleic Acid Drug Dev. 2002;12(3):193-213. Akiyama T et al. The product of the human c-erbB-2 gene: a 185-kilodalton glycoprotein with tyrosine kinase activity. Science. 1986;232(4758):1644-6. Rebouissou S et al. EGFR as a potential therapeutic target for a subset of muscle-invasive bladder cancers presenting a basal-like phenotype. Sci Transl Med. 2014;6(244):244ra91. Philips G et al. Phase II trial of cisplatin (C), fixed-dose gemcitabine (G) and gefitinib for advanced transitional cell carcinoma (TCC) of the urothelial tract: preliminary results of CALGB 90102. J Clin Oncol. 2004;22(Suppl 14):4538. Powles T et al. A phase II/III, double-blind, randomized trial comparing maintenance lapatinib versus placebo after first line chemotherapy in HER1/2 positive metastatic bladder cancer patients. J Clin Oncol. 2015;33(Suppl 15):4505. Wülfing C et al. A single arm, multicenter, open label, phase II study of lapatinib as 2L treatment of pts with locally advanced/metastatic transitional cell carcinoma (TCC) of the urothelial tract. J Clin Oncol. 2005;23(Suppl 16):4594. Laé M et al. Assessing HER2 gene amplification as a potential target for therapy in invasive urothelial bladder cancer with a standardized methodology: results in 1005 patients. Ann Oncol. 2010;21(4):815-9. Hussain M et al. Trastuzumab (T), paclitaxel (P), carboplatin (C), gemcitabine (G) in advanced HER2-positive urothelial carcinoma: results of a multi-center phase II NCI trial. J Clin Oncol. 2005;23(Suppl 16):4507. Hussain MH et al.; National Cancer Institute (NCI). Trastuzumab, paclitaxel, carboplatin, and gemcitabine in advanced human epidermal growth factor receptor-2/neu-positive urothelial carcinoma: results of a multicenter phase II National Cancer Institute trial. J Clin Oncol. 2007;25(16):2218-24. Ching CB, Hansel DE. Expanding therapeutic targets in bladder cancer: the PI3K/Akt/mTOR pathway. Lab Invest. 2010;90(10):1406-14. Wu D et al. Phosphatidylinositol 3-kinase inhibitor LY294002 suppresses proliferation and sensitizes doxorubicin chemotherapy in bladder cancer cells. Urol Int. 2011;86(3):346-54. Moon DG et al. NVP-BEZ235, a dual PI3K/mTOR inhibitor synergistically potentiates the antitumor effects of cisplatin in bladder cancer cells. Int J Oncol. 2014;45(3):1027-35. Milowsky MI et al. Phase II study of everolimus in metastatic urothelial cancer. BJU Int. 2013;112(4):462-70. Yang CC et al. The expression of vascular endothelial growth factor in transitional cell carcinoma of urinary bladder is correlated with cancer progression. Urol Oncol. 2004;22(1):1-6. Slaton JW et al. Correlation of metastasis related gene expression and relapse-free survival in patients with locally advanced bladder cancer treated with cystectomy and chemotherapy. J Urol. 2004;171(2:1):570-4. Kopparapu PK et al. Expression of VEGF and its receptors VEGFR1/VEGFR2 is associated with invasiveness of bladder cancer. Anticancer Res. 2013;33(6):2381-90. Sadaf A et al. Significance of vascular endothelial growth factor expression in the bladder urothelial carcinoma and its association with tumor grade and invasiveness. Iran J Pathol. 2021;16(4):362-9. Kunze D et al. Antisense-mediated inhibition of survivin, hTERT and VEGF in bladder cancer cells in vitro and in vivo. Int J Oncol. 2008;32:1049-56. Nakanishi R et al. Effect of vascular endothelial growth factor and its receptor inhibitor on proliferation and invasion in bladder cancer. Uro Int. 2009;83(1):98-106. Videira PA et al. Effects of bevacizumab on autocrine VEGF stimulation in bladder cancer cell lines. Urol Int. 2011;86(1):95-101. Fus ŁP, Górnicka B. Role of angiogenesis in urothelial bladder carcinoma. Cent European J Urol. 2016;69(3):258-63. Schulz GB, Karl A, “The value of anti-angiogenicsin bladder cancer therapy,” Marmé, D (ed.) Tumor Angiogenesis: A Key Target for Cancer Therapy (2017) London: Springer International Publishing, pp.1-13. Wołącewicz M et al. Immunotherapy in bladder cancer: current methods and future perspectives. Cancers (Basel). 2020;12(5):1181. Pagliarulo V et al. Celecoxib for the prevention of nonmuscle invasive bladder cancer: results from a matched control study. Ther Adv Urol. 2015;7(6):303-11. Shariat et al. Association of angiogenesis related markers with bladder cancer outcomes and other molecular markers. J Urol. 2010;183(5):1744-50. Karyekar CS et al. Pharmacokinetics (PK) of the angiogenesis inhibitor ABT-510 in healthy subjects. J Clin Oncol. 2004;22(Suppl 14):3080. Reiher FK et al. Inhibition of tumor growth by systemic treatment with thrombospondin-1 peptide mimetics. Int J Cancer. 2002;98(5):682-9. Basu A, Sadeghi S. Neoadjuvant therapies for bladder cancer in cisplatin-ineligible patients: what options do we have? Eur Urol Focus. 2020;6(4):623-6.

Please rate the quality of this content

As you found this content interesting...

Follow us on social media!

We are sorry that this content was not interesting for you!

Let us improve this content!

Tell us how we can improve this content?

Keep your finger on the pulse

Join Now

Elevating the Quality of Healthcare Globally

>