Novel therapeutic targets in bladder cancer: mutation and expression of FGF receptors

Phase 3 THOR Japanese subgroup analysis: erdafitinib in advanced or metastatic urothelial cancer and fibroblast growth factor receptor alterations

BACKGROUND

In the THOR trial (NCT03390504) Cohort 1, erdafitinib demonstrated significantly prolonged overall survival (OS) (median 12.1 versus 7.8 months) and reduced risk of death by 36% (hazard ratio 0.64, P = 0.005) compared with chemotherapy in metastatic urothelial carcinoma (mUC) patients with FGFR alterations who progressed after ≥ 1 prior treatments, including anti-PD-(L)1. There have been no reports of the Japanese subgroup results yet.

METHODS

THOR Cohort 1 randomized patients to erdafitinib once daily or docetaxel/vinflunine once every 3 weeks. Primary endpoint was OS. Secondary endpoints included progression-free survival (PFS) and objective response rate (ORR). No specific statistical power was set for this Japanese subgroup analysis.

RESULTS

Of 266 patients randomized, 27 (14 erdafitinib; 13 chemotherapy) were Japanese. Baseline characteristics were generally similar between treatments and to the overall population, except for more males, lower body weight, and more upper tract primary tumors among Japanese patients. Compared with chemotherapy, erdafitinib showed improved OS (median 25.4 versus 12.4 months), PFS (median 8.4 versus 2.9 months) and ORR (57.1% versus 15.4%). Any grade treatment-related adverse events (AEs) occurred in all patients from both arms but Grade 3/4 AEs and AEs leading to discontinuation were lower in the erdafitinib arm. No new safety signals were observed in the Japanese subgroup.

CONCLUSION

In the Japanese subgroup, erdafitinib showed improved survival and response compared to chemotherapy, with no new safety concerns. These results support erdafitinib as a treatment option for Japanese mUC patients with FGFR alterations, and early FGFR testing after diagnosis of mUC should be considered.

The role of lidocaine in cancer progression and patient survival

Since its development in 1943, lidocaine has been one of the most commonly used local anesthesia agents for surgical procedures. Lidocaine alters neuronal signal transmission by prolonging the inactivation of fast voltage-gated sodium channels in the cell membrane of neurons, which are responsible for action potential propagation. Recently, it has attracted attention due to emerging evidence suggesting its potential antitumor properties, particularly in the in vitro setting. Further, local administration of lidocaine around the tumor immediately prior to surgical removal has been shown to improve overall survival in breast cancer patients. However, the exact mechanisms driving these antitumor effects remain largely unclear. In this article, we will review the existing literature on the mechanism of lidocaine as a local anesthetic, its effects on the cancer cells and the tumor microenvironment, involved pathways, and cancer progression. Additionally, we will explore recent reports highlighting its impact on clinical outcomes in cancer patients. Taken together, there remains significant ambiguity surrounding lidocaine's functions and roles in cancer biology, particularly in perioperative setting.

Role of Basic Fibroblast Growth Factor in Cancer: Biological Activity, Targeted Therapies, and Prognostic Value

Cancer is the leading cause of death worldwide; thus, it is necessary to find successful strategies. Several growth factors, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF, FGF2), and transforming growth factor beta (TGF-β), are involved in the main processes that fuel tumor growth, i.e., cell proliferation, angiogenesis, and metastasis, by activating important signaling pathways, including PLC-γ/PI3/Ca2+ signaling, leading to PKC activation. Here, we focused on bFGF, which, when secreted by tumor cells, mediates several signal transductions and plays an influential role in tumor cells and in the development of chemoresistance. The biological mechanism of bFGF is shown by its interaction with its four receptor subtypes: fibroblast growth factor receptor (FGFR) 1, FGFR2, FGFR3, and FGFR4. The bFGF–FGFR interaction stimulates tumor cell proliferation and invasion, resulting in an upregulation of pro-inflammatory and anti-apoptotic tumor cell proteins. Considering the involvement of the bFGF/FGFR axis in oncogenesis, preclinical and clinical studies have been conducted to develop new therapeutic strategies, alone and/or in combination, aimed at intervening on the bFGF/FGFR axis. Therefore, this review aimed to comprehensively examine the biological mechanisms underlying bFGF in the tumor microenvironment, the different anticancer therapies currently available that target the FGFRs, and the prognostic value of bFGF.

Comprehensive FGFR3 alteration-related transcriptomic characterization is involved in immune infiltration and correlated with prognosis and immunotherapy response of bladder cancer

Background

Bladder cancer (BC) threatens the health of human beings worldwide because of its high recurrence rate and mortality. As an actionable biomarker, fibroblast growth factor receptor 3 (FGFR3) alterations have been revealed as a vital biomarker and associated with favorable outcomes in BC. However, the comprehensive relationship between the FGFR3 alteration associated gene expression profile and the prognosis of BC remains ambiguous.

Materials and Methods

Genomic alteration profile, gene expression data, and related clinical information of BC patients were downloaded from The Cancer Genomics database (TCGA), as a training cohort. Subsequently, the Weighted Gene Co-expression Network Analysis (WGCNA) was conducted to identify the hub modules correlated with FGFR3 alteration. The univariate, multivariate, and least absolute shrinkage and selection operator (LASSO) Cox regression analyses were used to obtain an FGFR3 alteration-related gene (FARG) prognostic signature and FARG-based nomogram. The receiver operating characteristic (ROC) curve analysis was used for evaluation of the ability of prognosis prediction. The FARG signature was validated in four independent datasets, namely, GSE13507, GSE31684, GSE32548, and GSE48075, from Gene Expression Omnibus (GEO). Then, clinical feature association analysis, functional enrichment, genomic alteration enrichment, and tumor environment analysis were conducted to reveal differential clinical and molecular characterizations in different risk groups. Lastly, the treatment response was evaluated in the immunotherapy-related dataset of the IMvigor210 cohort and the frontline chemotherapy dataset of GSE48276, and the chemo-drug sensitivity was estimated via Genomics of Drug Sensitivity in Cancer (GDSC).

Results

There were a total of eleven genes (CERCAM, TPST1, OSBPL10, EMP1, CYTH3, NCRNA00201, PCDH10, GAP43, COLQ, DGKB, and SETBP1) identified in the FARG signature, which divided BC patients from the TCGA cohort into high- and low-risk groups. The Kaplan–Meier curve analysis demonstrated that BC patients in the low-risk group have superior overall survival (OS) than those in the high-risk group (median OS: 27.06 months vs. 104.65 months, p < 0.0001). Moreover, the FARG signature not only showed a good performance in prognosis prediction, but also could distinguish patients with different neoplasm disease stages, notably whether patients presented with muscle invasive phenotype. Compared to clinicopathological features, the FARG signature was found to be the only independent prognostic factor, and subsequently, a FARG-based prognostic nomogram was constructed with better ability of prognosis prediction, indicated by area under ROC curve (AUC) values for 1-, 3-, and 5-year OS of 0.69, 0.71, and 0.79, respectively. Underlying the FARG signature, multiple kinds of metabolism- and immune-related signaling pathways were enriched. Genomic alteration enrichment further identified that FGFR3 alterations, especially c.746C>G (p.Ser249Cys), were more prevalent in the low-risk group. Additionally, FARG score was positively correlated with ESTIMATE and TIDE scores, and the low-risk group had abundant enrichment of plasma B cells, CD8+ T cells, CD4+ naive T cells, and helper follicular T cells, implying that patients in the low-risk group were likely to make significant responses to immunotherapy, which was further supported by the analysis in the IMvigor210 cohort as there was a significantly higher response rate among patients with lower FARG scores. The analysis of the GDSC database finally demonstrated that low-risk samples were more sensitive to methotrexate and tipifarnib, whereas those in the high-risk group had higher sensitivities in cisplatin, docetaxel, and paclitaxel, instead.

Conclusion

The novel established FARG signature based on a comprehensive FGFR3 alteration-related transcriptomic profile performed well in prognosis prediction and was also correlated with immunotherapy and chemotherapy treatment responses, which had great potential in future clinical applications.

Emerging strategies for the improvement of chemotherapy in bladder cancer: Current knowledge and future perspectives

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The response of chemotherapy and prognosis in bladder cancer is unsatisfied.

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Immunotherapy, targeted therapy, and ADC improve the efficacy of chemotherapy.

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Emerging targets in cancer cells and TME spawned novel preclinical agents.

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Novel drug delivery, such as nanotechnology, enhances effects of chemotherapeutics.

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The organoid and PDX model are promising to screen and evaluate the target therapy.

Background

Chemotherapy is a first-line treatment for advanced and metastatic bladder cancer, but the unsatisfactory objective response rate to this treatment yields poor 5-year patient survival. Only PD-1/PD-L1-based immune checkpoint inhibitors, FGFR3 inhibitors and antibody-drug conjugates are approved by the FDA to be used in bladder cancer, mainly for platinum-refractory or platinum-ineligible locally advanced or metastatic urothelial carcinoma. Emerging studies indicate that the combination of targeted therapy and chemotherapy shows better efficacy than targeted therapy or chemotherapy alone. Newly identified targets in cancer cells and various functions of the tumour microenvironment have spawned novel agents and regimens, which give impetus to sensitizing chemotherapy in the bladder cancer setting.

Aim of Review

This review aims to present the current evidence for potentiating the efficacy of chemotherapy in bladder cancer. We focus on combining chemotherapy with other treatments as follows: targeted therapy, including immunotherapy and antibody-drug conjugates in clinic; novel targeted drugs and nanoparticles in preclinical models and potential targets that may contribute to chemosensitivity in future clinical practice. The prospect of precision therapy is also discussed in bladder cancer.

Key Scientific Concepts of Review

Combining chemotherapy drugs with immune checkpoint inhibitors, antibody-drug conjugates and VEGF inhibitors potentially elevates the response rate and survival. Novel targets, including cancer stem cells, DNA damage repair, antiapoptosis, drug metabolism and the tumour microenvironment, contribute to chemosensitization. Gene alteration-based drug selection and patient-derived xenograft- and organoid-based drug validation are the future for precision therapy.

The Prognostic Value of FGFR3 Expression in Patients with T1 Non-Muscle Invasive Bladder Cancer

Purpose

Fibroblast growth factor receptor 3 (FGFR3) alterations are frequent in non-muscle-invasive bladder cancer (NMIBC), although current data regarding the prognostic and therapeutic relevance are inconsistent. We analyzed the prognostic role of FGFR3 mRNA expression in stage T1 NMIBC.

Patients and Methods

The mRNA expression of FGFR3 and cyclin-dependent kinase inhibitor 2A (CDKN2A) was measured by RT-qPCR in 80 patients with stage T1 NMIBC treated with transurethral resection of the bladder and correlated with clinical data and KRT5 and KRT20 expression, used as surrogate markers for basal and luminal subtypes, respectively.

Results

FGFR3 and CDKN2A transcript levels were not correlated. FGFR3 expression was associated with the expression of KRT5 (p=0.002) and KRT20 (p < 0.001). CDKN2A expression was negatively correlated with KRT5 (p=0.030). In Kaplan–Meier analysis and univariable Cox regression analysis, high FGFR3 expression was associated with significantly reduced recurrence-free survival (RFS) (HR=3.78; p < 0.001) and improved overall survival (OS) (HR=0.50; p=0.043), while high CDKN2A expression was associated with reduced OS (HR=2.34; p=0.034). Patient age was the only clinicopathological parameter associated with reduced OS (HR=2.29; p=0.022). No parameter was an independent prognostic factor in multivariable analysis. Next, we stratified the patients depending on their lineage differentiation. In univariable analysis, the prognostic effect of FGFR3 and CDKN2A was observed primarily in patients demonstrating high expression of KRT5 or KRT20, whereas high FGFR3 expression was associated with significantly reduced RFS, irrespective of instillation therapy.

Conclusion

Stage T1 NMIBC patients with high FGFR3 expression show shorter RFS but better OS than patients with low FGFR3 expression.

FGF9 inhibition by a novel binding peptide has efficacy in gastric and bladder cancer per se and reverses resistance to cisplatin

Aberrant over-expressions of FGF9 in gastric cancer (GC) and its high-affinity receptor FGFR3c in bladder cancer (BC) provide possibilities for the treatment of GC and BC via targeting FGF9. In this study, we isolated a novel FGF9-binding peptide (P4) by screening a phage display random heptapeptide library. Sequence comparison showed that P4 shared high homology with the conserved motif in the immunoglobulin-like (Ig-like) domain II∼III (D2-D3) linker of the FGF9 high-affinity receptor (FGFR3c). The interaction between P4 and FGF9 was confirmed by the surface plasmon resonance (SPR) assay. Functional analysis indicated that P4 counteracted FGF9-induced aggressive phenotype, including cell proliferation, migration, and invasion in vitro, as well as suppressed tumor growth in vivovia down-regulation of the MAPKs and Akt cascades. More importantly, we found that FGF9 served as an underlying mechanism of the chemoresistance in GC and BC cells, and P4 could increase the sensitivity to the chemical agent via antagonizing the suppression effects of FGF9 on cell apoptosis. Taken together, our study identified a novel binding peptide for FGF9, which may serve as a potential therapeutic agent for malignant tumors featured by abnormally up-regulation of FGF9.

Urine Biopsy-Liquid Gold for Molecular Detection and Surveillance of Bladder Cancer

With recent advancements in a non-invasive approach to cancer diagnosis and surveillance, the term "liquid biopsy" has gained traction but is currently limited by technological challenges in identifying and isolating circulating tumor cells (CTCs), proteins, cell-free DNA (cfDNA), or other nucleic acids. Tumor tissue biopsy, especially in genitourinary (GU) system is sometimes inadequate and requires invasive surgical options, especially for upper tract urothelial cancer. Urine can prove to be "liquid gold" since it may be a more abundant source of tumor-derived material without the background noise; however, urine DNA (uDNA) may be associated with low mutant allele fraction (MAF). Molecular detection of mutations in uDNA requires a sensitive and accurate method of analysis that allows a high depth of sequencing while minimizing artifacts. Several sequencing approaches to address this hurdle using enhanced library preparation techniques such as Tagged amplicon deep sequencing (TAm-Seq), Safe-SeqS, FAST-SeqS, and CAPP-Seq approaches have been developed. Urine biopsy utilizing next-generation sequencing (NGS) can prove useful at all stages of urologic malignancy care, where urine can be collected to aid in clinical decision making through the identification of commonly known mutations, and potentially reduce or avoid all forms of invasive procedures.

Celecoxib in breast cancer prevention and therapy

Breast cancer has a high incidence worldwide. The results of substantial studis reveal that inflammation plays an important role in the initiation, development, and aggressiveness of many malignancies. The use of celecoxib, a novel NSAID, is repetitively associated with the reduced risk of the occurrence and progression of a number of types of cancer, particularly breast cancer. This observation is also substantiated by various meta-analyses. Clinical trials have been implemented on integration treatment of celecoxib and shown encouraging results. Celecoxib could be treated as a potential candidate for antitumor agent. There are, nonetheless, some unaddressed questions concerning the precise mechanism underlying the anticancer effect of celecoxib as well as its activity against different types of cancer. In this review, we discuss different mechanisms of anticancer effect of celecoxib as well as preclinical/clinical results signifying this beneficial effect.

Mutant FGFR3 associated with SADDAN disease causes cytoskeleton disorganization through PLCγ1/Src-mediated paxillin hyperphosphorylation

K650M/E substitutions in the Fibroblast growth factor receptor 3 (FGFR3) are associated with Severe Achondroplasia with Developmental Delay and Acanthosis Nigricans (SADDAN) and Thanatophoric Dysplasia type II (TDII), respectively. Both SADDAN and TDII present with affected endochondral ossification marked by impaired chondrocyte functions and growth plate disorganization. In vitro, K650M/E substitutions confer FGFR3 constitutive kinase activity leading to impaired biosynthesis and accumulation of immature receptors in endoplasmic reticulum (ER)/Golgi. From those compartments, both SADDAN-FGFR3 and TDII-FGFR3 receptors engender uncontrolled signalling, activating PLCγ1, signal transducer and activator of transcription 1, 3 and 5 (STAT1/3/5) and ERK1/2 effectors. Here, we investigated the impact of SADDAN-FGFR3 and TDII-FGFR3 signalling on cytoskeletal organization. We report that SADDAN-FGFR3, but not TDII-FGFR3, affects F-actin organization by inducing tyrosine hyperphosphorylation of paxillin, a key regulator of focal adhesions and actin dynamics. Paxillin phosphorylation was upregulated at tyrosine 118, a functional target of Src and FAK kinases. By using Src-deficient cells and a Src kinase inhibitor, we established a role played by Src activation in paxillin hyperphosphorylation. Moreover, we found that SADDAN-FGFR3 induced FAK phosphorylation at tyrosines 576/577, suggesting its involvement as a Src co-activator in paxillin phosphorylation. Interestingly, paxillin hyperphosphorylation by SADDAN-FGFR3 caused paxillin mislocalization and partial co-localization with the mutant receptor. Finally, the SADDAN-FGFR3 double mutant unable to bind PLCγ1 failed to promote paxillin hyperphosphorylation, pointing to PLCγ1 as an early player in mediating paxillin alterations. Overall, our findings contribute to elucidate the molecular mechanism leading to cell dysfunctions caused by SADDAN-FGFR3 signalling.

Eukaryotic elongation factor 2 is a prognostic marker and its kinase a potential therapeutic target in HCC

Hepatocellular carcinoma is a cancer with increasing incidence and largely refractory to current anticancer drugs. Since Sorafenib, a multikinase inhibitor has shown modest efficacy in advanced hepatocellular carcinoma additional treatments are highly needed. Protein phosphorylation via kinases is an important post-translational modification to regulate cell homeostasis including proliferation and apoptosis. Therefore kinases are valuable targets in cancer therapy. To this end we performed 2D differential gel electrophoresis and mass spectrometry analysis of phosphoprotein-enriched lysates of tumor and corresponding non-tumorous liver samples to detect differentially abundant phosphoproteins to screen for novel kinases as potential drug targets. We identified 34 differentially abundant proteins in phosphoprotein enriched lysates. Expression and distribution of the candidate protein eEF2 and its phosphorylated isoform was validated immunohistochemically on 78 hepatocellular carcinoma and non-tumorous tissue samples. Validation showed that total eEF2 and phosphorylated eEF2 at threonine 56 are prognostic markers for overall survival of HCC-patients. The activity of the regulating eEF2 kinase, compared between tumor and non-tumorous tissue lysates by in vitro kinase assays, is more than four times higher in tumor tissues. Functional analyzes regarding eEF2 kinase were performed in JHH5 cells with CRISPR/Cas9 mediated eEF2 kinase knock out. Proliferation and growth is decreased in eEF2 kinase knock out cells.

Therapeutic potentials of baicalin and its aglycone, baicalein against inflammatory disorders

The flavonoids, baicalin (5,6-dihydroxy-2-phenyl-4H-1-benzopyran-4-one-7-O-d-β-glucuronic acid) 1 and its aglycone, baicalein 2 are found in edible medicinal plants, Scutellaria baicalensis Georgi and Oroxylum indicum (L.) Kurz in abundant quantities. The antioxidant and anti-inflammatory effects of these flavonoids have been demonstrated in various disease models, including diabetes, cardiovascular diseases, inflammatory bowel diseases, gout and rheumatoid arthritis, asthma, neurodegenerative-, liver- and kidney diseases, encephalomyelitis, and carcinogenesis. These flavonoids have almost no toxicity to human normal epithelial, peripheral and myeloid cells. Their antioxidant and anti-inflammatory activities are largely due to their abilities to scavenge the reactive oxygen species (ROS) and improvement of antioxidant status by attenuating the activity of NF-κB and suppressing the expression of several inflammatory cytokines and chemokines including monocyte chemotactic protein-1 (MCP-1), nitric oxide synthase, cyclooxygenases, lipoxygenases, cellular adhesion molecules, tumor necrosis factor and interleukins. In this review, we summarize the antioxidant and anti-inflammatory effects of baicalin and baicalein with molecular mechanisms for their chemopreventive and chemotherapeutic applications in the treatment of inflammatory-related diseases.

A Phase II Trial of Dovitinib in BCG-Unresponsive Urothelial Carcinoma with FGFR3 Mutations or Overexpression: Hoosier Cancer Research Network Trial HCRN 12-157

Purpose: To assess the clinical and pharmacodynamic activity of dovitinib in a treatment-resistant, molecularly enriched non-muscle-invasive urothelial carcinoma of the bladder (NMIUC) population.Experimental Design: A multi-site pilot phase II trial was conducted. Key eligibility criteria included the following: Bacillus Calmette-Guerin (BCG)-unresponsive NMIUC (>2 prior intravesical regimens) with increased phosphorylated FGFR3 (pFGFR3) expression by centrally analyzed immunohistochemistry (IHC+) or FGFR3 mutations (Mut+) assessed in a CLIA-licensed laboratory. Patients received oral dovitinib 500 mg daily (5 days on/2 days off). The primary endpoint was 6-month TURBT-confirmed complete response (CR) rate.Results: Between 11/2013 and 10/2014, 13 patients enrolled (10 IHC+ Mut-, 3 IHC+ Mut+). Accrual ended prematurely due to cessation of dovitinib clinical development. Demographics included the following: median age 70 years; 85% male; carcinoma in situ (CIS; 3 patients), Ta/T1 (8 patients), and Ta/T1 + CIS (2 patients); median prior regimens 3. Toxicity was frequent with all patients experiencing at least one grade 3-4 event. Six-month CR rate was 8% (0% in IHC+ Mut-; 33% in IHC+ Mut+). The primary endpoint was not met. Pharmacodynamically active (94-5,812 nmol/L) dovitinib concentrations in urothelial tissue were observed in all evaluable patients. Reductions in pFGFR3 IHC staining were observed post-dovitinib treatment.Conclusions: Dovitinib consistently achieved biologically active concentrations within the urothelium and demonstrated pharmacodynamic pFGFR3 inhibition. These results support systemic administration as a viable approach to clinical trials in patients with NMIUC. Long-term dovitinib administration was not feasible due to frequent toxicity. Absent clinical activity suggests that patient selection by pFGFR3 IHC alone does not enrich for response to FGFR3 kinase inhibitors in urothelial carcinoma. Clin Cancer Res; 23(12); 3003-11. ©2016 AACR.

Fibroblast growth factor receptor signaling in hereditary and neoplastic disease: biologic and clinical implications

Fibroblast growth factors (FGFs) and their receptors (FGFRs) are transmembrane growth factor receptors with wide tissue distribution. FGF/FGFR signaling is involved in neoplastic behavior and also development, differentiation, growth, and survival. FGFR germline mutations (activating) can cause skeletal disorders, primarily dwarfism (generally mutations in FGFR3), and craniofacial malformation syndromes (usually mutations in FGFR1 and FGFR2); intriguingly, some of these activating FGFR mutations are also seen in human cancers. FGF/FGFR aberrations reported in cancers are mainly thought to be gain-of-function changes, and several cancers have high frequencies of FGFR alterations, including breast, bladder, or squamous cell carcinomas (lung and head and neck). FGF ligand aberrations (predominantly gene amplifications) are also frequently seen in cancers, in contrast to hereditary syndromes. There are several pharmacologic agents that have been or are being developed for inhibition of FGFR/FGF signaling. These include both highly selective inhibitors as well as multi-kinase inhibitors. Of note, only four agents (ponatinib, pazopanib, regorafenib, and recently lenvatinib) are FDA-approved for use in cancer, although the approval was not based on their activity against FGFR. Perturbations in the FGFR/FGF signaling are present in both inherited and malignant diseases. The development of potent inhibitors targeting FGF/FGFR may provide new tools against disorders caused by FGF/FGFR alterations.

FGFR3-TACC3 fusion proteins act as naturally occurring drivers of tumor resistance by functionally substituting for EGFR/ERK signaling

The epidermal growth factor receptor (EGFR) is a clinically validated target in head and neck squamous cell carcinoma (HNSCC), where EGFR-blocking antibodies are approved for first-line treatment. However, as with other targeted therapies, intrinsic/acquired resistance mechanisms limit efficacy. In the FaDu HNSCC xenograft model, we show that combined blockade of EGFR and ERBB3 promotes rapid tumor regression, followed by the eventual outgrowth of resistant cells. RNA sequencing revealed that resistant cells express FGFR3-TACC3 fusion proteins, which were validated as drivers of the resistant phenotype by several approaches, including CRISPR-mediated inactivation of FGFR3-TACC3 fusion genes. Interestingly, analysis of signaling in resistant cell lines demonstrated that FGFR3-TACC3 fusion proteins promote resistance by preferentially substituting for EGFR/RAS/ERK signaling rather than ERBB3/PI3K/AKT signaling. Furthermore, although FGFR3-TACC3 fusion proteins promote resistance of additional EGFR-dependent HNSCC and lung cancer cell lines to EGFR blockade, they are unable to compensate for inhibition of PI3K signaling in PIK3CA-mutant HNSCC cell lines. Validation of FGFR3-TACC3 fusion proteins as endogenous drivers of resistance in our screen provides strong evidence that these fusions are capable of substituting for EGFR signaling. Thus, FGFR3-TACC3 fusion proteins may represent a novel mechanism of acquired resistance in EGFR-dependent cancers of multiple cell lineages.

The geriatrics and genetics behind bladder cancer

Bladder cancer is a disease of older patients who often have multiple comorbidities. Although cisplatin-based combination chemotherapy is the standard of care in the neoadjuvant and metastatic settings, outcomes remain poor, and approximately half of patients are ineligible for cisplatin where treatment options are severely limited. Recent comprehensive genome sequencing studies have defined the mutational spectra of high-grade urothelial carcinoma of the bladder. Although there is a high prevalence of potentially actionable genomic alterations, whether these events represent true oncogenic vulnerabilities has yet to be confirmed. Given the demographics and genetics, we propose that bladder cancer represents an ideal model to study the potential of targeted therapy in older patients who are too often unable to receive cisplatin-based therapy and where novel treatment strategies are desperately needed.

Phase 2 trial of dovitinib in patients with progressive FGFR3-mutated or FGFR3 wild-type advanced urothelial carcinoma

BACKGROUND

Second-line treatment options for patients with advanced urothelial carcinoma (UC) are limited. Fibroblast growth factor receptor 3 (FGFR3) is dysregulated in UC by activating mutations or protein overexpression in non-mutant tumours. In this study, the efficacy, pharmacodynamics and safety of dovitinib-a broad-targeted inhibitor of tyrosine kinases, including FGFR3-were evaluated in patients with previously treated advanced UC with and without FGFR3 mutations.

METHODS

Forty-four adults with advanced UC who had progressed after one to three platinum-based and/or combination chemotherapy regimens were classified as having mutant (FGFR3(MUT); n=12), wild-type (FGFR3(WT); n=31), or unknown (n=1) FGFR3 status. Patients received 500 mg dovitinib once daily on a 5-days-on/2-days-off schedule. The primary end-point of this two-stage study was the investigator-assessed overall response rate (ORR).

RESULTS

Most of the patients were men (75%) and over half of the patients were aged ⩾65 years (61%). All patients had received ⩾1 prior antineoplastic therapy for UC. The study was terminated at the end of stage 1, when it was determined by investigator review that the ORR of both the FGFR3(MUT) (0%; 95% confidence interval [CI], 0.0-26.5) and FGFR3(WT) (3.2%; 95% CI, 0.1-16.7) groups did not meet the criteria to continue to stage 2. The most common grade 3/4 adverse events, suspected to be study-drug related, included thrombocytopenia (9%), fatigue (9%), and asthenia (9%).

CONCLUSION

Although generally well tolerated, dovitinib has very limited single-agent activity in patients with previously treated advanced UC, regardless of FGFR3 mutation status. clinicaltrials.gov NCT00790426.

Increased angiogenesis and FGFR protein expression indicate a favourable prognosis in bladder cancer

Compared to other members of the fibroblast growth factor receptor (FGFR) family, only few studies investigate FGFR3 in tumour angiogenesis. We investigated the connection between angiogenesis and FGF/FGFR expression including FGFR3 mutation status in urothelial carcinomas. Immunohistochemistry was performed in invasive and non-invasive urothelial cancers of 61 patients. Protein expression of CD31, factor VIII (FVIII), FGF-1/2, FGFR1, FGFR3 and FGFR4 and FGFR3 mutation status were evaluated. Morphometric assessment of angiogenesis including microvessel count (MVC) and vascular surface area (VSA) was analysed. Correlation and survival analyses (overall survival (OS) and disease-free survival (DFS)) with univariate and multivariate analyses were performed. CD31 values (MVC and VSA) significantly correlated with OS and DFS. OS and DFS were significantly better in patients with FGFR3 overexpression. Multivariate analysis revealed FGFR3 protein expression and tumour grading (WHO classification 2004) as independent prognostic factors of OS and VSA of CD31 and FGFR3 protein expression of DFS. FGFR3 mutation status was correlated with VSA measured by FVIII. FGFR3 may be able to induce a pro-angiogenic phenotype in urothelial carcinomas and significantly influence prognosis. Consequently, FGFR3 is a potential therapeutic target also from the angiogenesis perspective.

Alteration of cell-cell and cell-matrix adhesion in urothelial cells: an oncogenic mechanism for mutant FGFR3

Activating mutations of FGFR3 are a common and early event in bladder cancer. Ectopic expression of mutant FGFR3 in normal urothelial cells has both pro-proliferative and antiapoptotic effects at confluence, suggesting that mutant cells are insensitive to cell-cell contact inhibition. Herein, detailed analysis revealed that these cells have reduced cell-cell adhesion, with large intercellular spaces observable at confluence, and diminished cell-substrate adhesion to collagen IV, collagen I, and fibronectin. These phenotypic alterations are accompanied by changes in the expression of genes involved in cell adhesion and extracellular matrix remodeling. Silencing of endogenous mutant FGFR3 in bladder cancer cells induced converse changes in transcript levels of CDH16, PLAU, MMP10, EPCAM, TNC, and HAS3, confirming them as downstream gene targets of mutant FGFR3. Overexpression of EPCAM, HAS3, and MMP10 transcripts was found in a large fraction of primary bladder tumors analyzed, supporting their key role in bladder tumorigenesis in vivo. However, no correlation was found between their protein and/or mRNA expression and FGFR3 mutation status in tumor specimens, indicating that these genes may be targeted by several converging oncogenic pathways. Overall, these results indicate that mutant FGFR3 favors the development and progression of premalignant bladder lesions by altering key genes regulating the cell-cell and cell-matrix adhesive properties of urothelial cells.

IMPLICATIONS

The ability of mutant FGFR3 to drive transcriptional expression profiles involved in tumor cell adhesion suggests a mechanism for expansion of premalignant urothelial lesions.

Phase Ib study of dovitinib in combination with gemcitabine plus cisplatin or gemcitabine plus carboplatin in patients with advanced solid tumors

PURPOSE

Dovitinib is a small molecule kinase inhibitor with activity against the fibroblast growth factor and vascular endothelial growth factor receptor families. The purpose of this phase Ib study was to define the recommended phase 2 dose of the combinations of gemcitabine and cisplatin or gemcitabine and carboplatin plus dovitinib.

METHODS

Patients with advanced solid tumors were enrolled in two parallel dose escalation arms (cisplatin- or carboplatin-based regimens). Treatment was administered with gemcitabine (1,000 mg/m(2) on days 1 and 8), cisplatin (70 mg/m(2)), or carboplatin (AUC 5) on day 1, and dovitinib (orally on days 1-5, 8-12, and 15-19), every 21 days. The starting dose of dovitinib was 300 mg and was dose escalated in successive cohorts using 3 + 3 dose escalation rules.

RESULTS

Fourteen patients with advanced solid tumors were enrolled, five to the cisplatin arm and nine to the carboplatin arm. Patients enrolled in the cisplatin arm received a median of two cycles of treatment (range 1-5), and patients enrolled in the carboplatin arm received a median of one cycle of treatment (range 1-4). There were no protocol-defined dose-limiting toxicities in the cisplatin arm. However, the cohort was closed due to the need for frequent dose delays and/or reductions and two patients experiencing severe thromboembolic events. There were two dose-limiting toxicities in the carboplatin arm at the starting dose level of dovitinib (both prolonged neutropenia), and the dose of dovitinib was de-escalated to 200 mg. Two additional dose-limiting toxicities (prolonged neutropenia and febrile neutropenia) occurred in the lower dose cohort, and the study was closed. No patients achieved an objective response to treatment.

CONCLUSIONS

Dovitinib in combination with gemcitabine plus cisplatin or gemcitabine plus carboplatin was poorly tolerated due to myelosuppression.

Intrinsic basal and luminal subtypes of muscle-invasive bladder cancer

Whole-genome analyses have revealed that muscle-invasive bladder cancers (MIBCs) are heterogeneous and can be grouped into basal and luminal subtypes that are highly reminiscent of those found in breast cancer. Basal MIBCs are enriched with squamous and sarcomatoid features and are associated with advanced stage and metastatic disease at presentation. Like basal breast cancers, basal bladder tumours contain a claudin-low subtype that is enriched with biomarkers characteristic of epithelial-to-mesenchymal transition. The stem cell transcription factor ΔNp63α controls basal MIBC gene expression, just as it does in basal breast cancers. Luminal MIBCs are enriched with activating FGFR3 and ERBB3 mutations and ERBB2 amplifications, and their gene expression profiles are controlled by peroxisome proliferator activator receptor γ (PPARγ) and possibly also by oestrogen receptor activation. Luminal bladder cancers can be further subdivided into two subtypes, p53-like and luminal, which can be distinguished from one another by different levels of biomarkers that are characteristic of stromal infiltration, cell cycle progression, and proliferation. Importantly, basal bladder cancers are intrinsically aggressive, but are highly sensitive to cisplatin-based combination chemotherapy. Although the luminal subtypes are not as intrinsically aggressive as basal cancers, p53-like tumours are resistant to chemotherapy and might, therefore, represent a problem for treated patients.

Immunohistochemical analysis of chromatin remodeler DAXX in high grade urothelial carcinoma

Background/Aims

The chromatin remodeler DAXX, a predominantly nuclear protein, regulates the status of chromatin organization. The aim of this exploratory immunohistochemical study was to evaluate DAXX protein expression in high grade invasive urothelial carcinoma (UC) of the bladder as a biological regulator of aggressiveness.

Methods

Quantitative analysis was made on DAXX immunostained nuclei in tissue sections from 5 cases of bladder normal urothelium (NU) and 5 cases of bladder pT1 UC. Carcinoma in situ (CIS) and high grade papillary carcinoma (HGPCa) were identified in 2 out of 5 UC cases.

Results

The nuclei in UC show an open configuration of the chromatin composed of granules varying in size and distribution and a mean nuclear area 1.7 times greater than that in NU (UC: mean and SD 24.4 ± 11.4 square microns; NU: 14.8 6.5 square microns. The differences are statistically significant). 70% of the NU nuclei are immunostained, whereas 90% of UC nuclei are positive. The mean gray level value in UC, related to the intensity of nuclear immunostaining, is lower than in NU by a factor of 0.94 (UC: mean and SD 100 ± 15; NU: 106 ± 15. The differences are statistically significant). In particular, the value in the nuclei adjacent to the stroma in UC is slightly lower than in the intermediate cell layers by factor of 0.98, whereas in NU it is slightly greater by a factor 1.02 and 1.04 compared to the intermediate and superficial cell layers. The values in CIS and HGPCa are similar to those in UC.

Conclusions

The quantitative immunohistochemical analysis shows an altered protein expression of chromatin remodeler DAXX in UC and in its preinvasive phases, when compared to NU. DAXX evaluation, if associated with markers related to global DNA methylation and histone acetylation, could be used in clinical practice as a marker of aggressiveness.

Virtual slides

The virtual slides for this article can be found here:

http://www.diagnosticpathology.diagnomx.eu/vs/1398457297102379

An integrated genomic, transcriptional and protein investigation of FGFRL1 as a putative 4p16.3 deletion target in bladder cancer

Loss of heterozygosity (LOH) of chromosome arm 4p is a common event in bladder and other malignancies. At least three distinct regions of deletion have been identified, but the deletion targets have so far remained elusive. In this study, we have identified a novel region of deletion mapping to 4p16.3 spanning 0-2.1 Mb, in 15% of bladder tumors and 24% of bladder cancer cell lines. FGFRL1, which maps within this region, was investigated as putative deletion target. The retained FGFRL1 allele was not mutated in cell lines and tumors with LOH, although in patients heterozygous for the rs4647930 functional polymorphism, the common allele was preferentially lost in tumor tissue. Epigenetic silencing of the retained allele was also excluded as levels of FGFRL1 mRNA and protein were similar in cell lines and tumors with and without 4p16.3 loss. However, while FGFRL1 protein was moderately expressed in all layers of the normal bladder epithelium, the majority of tumors showed areas of downregulation. Overall, average FGFRL1 protein expression was significantly lower in bladder tumors compared to normal tissue, but downregulation was independent from 4p16.3 LOH status, FGFR3 mutation, and tumor grade and stage. In conclusion, although we found no evidence supporting a "two-hit" inactivation of FGFRL1 in bladder carcinogenesis, the effect of heterozygous deletion coupled with functional polymorphisms, and the role of post-transcriptional downregulation deserves further investigation.

Bioinformatics analysis of the gene expression profile in Bladder carcinoma

Bladder carcinoma, which has the ninth highest incidence among malignant tumors in the world, is a complex, multifactorial disease. The malignant transformation of bladder cells results from DNA mutations and alterations in gene expression levels. In this work, we used a bioinformatics approach to investigate the molecular mechanisms of bladder carcinoma. Biochips downloaded from the Gene Expression Omnibus (GEO) were used to analyze the gene expression profile in urinary bladder cells from individuals with carcinoma. The gene expression profile of normal genomes was used as a control. The analysis of gene expression revealed important alterations in genes involved in biological processes and metabolic pathways. We also identified some small molecules capable of reversing the altered gene expression in bladder carcinoma; these molecules could provide a basis for future therapies for the treatment of this disease.

5-((1-Aroyl-1H-indol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-diones as potential anticancer agents with anti-inflammatory properties

A series of novel 5-((1-aroyl-1H-indol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-diones (3a-z) have been evaluated for in vitro cytotoxicity against a panel of 60 human tumor cell lines. Compound 3k exhibited the most potent growth inhibition against melanoma MDA-MB-435 cells (GI(50)=850 nM), against leukemia SR cancer cells (GI(50)=1.45 μM), and OVCAR-3 (GI(50)=1.26 μM) ovarian cancer cell lines. The structurally related compound 3s had a GI(50) value of 1.77 μM against MDA-MB-435 cells. The N-naphthoyl analogue 3t had GI(50) values of 1.30 and 1.91 μM against HOP-92 non-small cell lung cancer and MDA-MB-435 melanoma cell lines, respectively. The related analogue 3w had GI(50) values of 1.09 μM against HOP-92 non-small cell lung cancer cell lines. Interestingly, docking of the two active molecules 3k and 3w into the active site of COX-2 indicates that these compounds are COX-2 ligands with strong hydrophobic and hydrogen bonding interactions. Thus, compounds 3k, 3t, 3s, and 3w constitute a new class of anticancer/anti-inflammatory agents that may have unique potential for cancer therapy.

Fibroblast growth factor receptors-1 and -3 play distinct roles in the regulation of bladder cancer growth and metastasis: implications for therapeutic targeting

Fibroblast growth factor receptors (FGFRs) are activated by mutation and overexpressed in bladder cancers (BCs), and FGFR inhibitors are currently being evaluated in clinical trials in BC patients. However, BC cells display marked heterogeneity in their responses to FGFR inhibitors, and the biological mechanisms underlying this heterogeneity are not well defined. Here we used a novel inhibitor of FGFRs 1–3 and RNAi to determine the effects of inhibiting FGFR1 or FGFR3 in a panel of human BC cell lines. We observed that FGFR1 was expressed in BC cells that also expressed the “mesenchymal” markers ZEB1 and vimentin, whereas FGFR3 expression was restricted to the E-cadherin- and p63-positive “epithelial” subset. Sensitivity to the growth-inhibitory effects of BGJ-398 was also restricted to the “epithelial” BC cells and it correlated directly with FGFR3 mRNA levels but not with the presence of activating FGFR3 mutations. In contrast, BGJ-398 did not strongly inhibit proliferation but did block invasion in the “mesenchymal” BC cells in vitro. Similarly, BGJ-398 did not inhibit primary tumor growth but blocked the production of circulating tumor cells (CTCs) and the formation of lymph node and distant metastases in mice bearing orthotopically implanted “mesenchymal” UM-UC3 cells. Together, our data demonstrate that FGFR1 and FGFR3 have largely non-overlapping roles in regulating invasion/metastasis and proliferation in distinct “mesenchymal” and “epithelial” subsets of human BC cells. The results suggest that the tumor EMT phenotype will be an important determinant of the biological effects of FGFR inhibitors in patients.

FGFR3 stimulates stearoyl CoA desaturase 1 activity to promote bladder tumor growth

Fibroblast growth factor receptor 3 (FGFR3) belongs to a family of receptor tyrosine kinases that control cell proliferation, differentiation, and survival. Aberrant activation of FGFR3 via overexpression or mutation is a frequent feature of bladder cancer; however, its molecular and cellular consequences and functional relevance to carcinogenesis are not well understood. Through transcriptional profiling of bladder carcinoma cells subjected to short hairpin RNA knockdown of FGFR3, we identified a gene-signature linking FGFR3 signaling with de novo sterol and lipid biosynthesis and metabolism. We found that FGFR3 signaling promotes the cleavage and activation of the master transcriptional regulator of lipogenesis, sterol regulatory element-binding protein 1(SREBP1/SREBF1), in a PI3K-mTORC1-dependent fashion. In turn, SREBP1 regulates the expression of key lipogenic enzymes, including stearoyl CoA desaturase 1 (SCD1/SCD). SCD1 is the rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids and is crucial for lipid homeostasis. In human bladder cancer cell lines expressing constitutively active FGFR3, knockdown of SCD1 by siRNA markedly attenuated cell-cycle progression, reduced proliferation, and induced apoptosis. Furthermore, inducible knockdown of SCD1 in a bladder cancer xenograft model substantially inhibited tumor progression. Pharmacologic inhibition of SCD1 blocked fatty acid desaturation and also exerted antitumor activity in vitro and in vivo. Together, these findings reveal a previously unrecognized role of FGFR3 in regulating lipid metabolism to maintain tumor growth and survival, and also identify SCD1 as a potential therapeutic target for FGFR3-driven bladder cancer.

Phosphoproteomics and lung cancer research

Massive evidence suggests that genetic abnormalities contribute to the development of lung cancer. These molecular abnormalities may serve as diagnostic, prognostic and predictive biomarkers for this deadly disease. It is imperative to search these biomarkers in different tumorigenesis pathways so as to provide the most appropriate therapy for each individual patient with lung malignancy. Phosphoproteomics is a promising technology for the identification of biomarkers and novel therapeutic targets for cancer. Thousands of proteins interact via physical and chemical association. Moreover, some proteins can covalently modify other proteins post-translationally. These post-translational modifications ultimately give rise to the emergent functions of cells in sequence, space and time. Phosphoproteomics clinical researches imply the comprehensive analysis of the proteins that are expressed in cells or tissues and can be employed at different stages. In addition, understanding the functions of phosphorylated proteins requires the study of proteomes as linked systems rather than collections of individual protein molecules. In fact, proteomics approaches coupled with affinity chromatography strategies followed by mass spectrometry have been used to elucidate relevant biological questions. This article will discuss the relevant clues of post-translational modifications, phosphorylated proteins, and useful proteomics approaches to identify molecular cancer signatures. The recent progress in phosphoproteomics research in lung cancer will be also discussed.

Phage displayed peptides/antibodies recognizing growth factors and their tyrosine kinase receptors as tools for anti-cancer therapeutics

The basic idea of displaying peptides on a phage, introduced by George P. Smith in 1985, was greatly developed and improved by McCafferty and colleagues at the MRC Laboratory of Molecular Biology and, later, by Barbas and colleagues at the Scripps Research Institute. Their approach was dedicated to building a system for the production of antibodies, similar to a naïve B cell repertoire, in order to by-pass the standard hybridoma technology that requires animal immunization. Both groups merged the phage display technology with an antibody library to obtain a huge number of phage variants, each of them carrying a specific antibody ready to bind its target molecule, allowing, later on, rare phage (one in a million) to be isolated by affinity chromatography. Here, we will briefly review the basis of the technology and the therapeutic application of phage-derived bioactive molecules when addressed against key players in tumor development and progression: growth factors and their tyrosine kinase receptors.

K-Ras and β-catenin mutations cooperate with Fgfr3 mutations in mice to promote tumorigenesis in the skin and lung, but not in the bladder

The human fibroblast growth factor receptor 3 (FGFR3) gene is frequently mutated in superficial urothelial cell carcinoma (UCC). To test the functional significance of FGFR3 activating mutations as a 'driver' of UCC, we targeted the expression of mutated Fgfr3 to the murine urothelium using Cre-loxP recombination driven by the uroplakin II promoter. The introduction of the Fgfr3 mutations resulted in no obvious effect on tumorigenesis up to 18 months of age. Furthermore, even when the Fgfr3 mutations were introduced together with K-Ras or β-catenin (Ctnnb1) activating mutations, no urothelial dysplasia or UCC was observed. Interestingly, however, owing to a sporadic ectopic Cre recombinase expression in the skin and lung of these mice, Fgfr3 mutation caused papilloma and promoted lung tumorigenesis in cooperation with K-Ras and β-catenin activation, respectively. These results indicate that activation of FGFR3 can cooperate with other mutations to drive tumorigenesis in a context-dependent manner, and support the hypothesis that activation of FGFR3 signaling contributes to human cancer.

Targeting fibroblast growth factor receptor 3 enhances radiosensitivity in human squamous cancer cells

Conventional therapies including radiation therapy cannot cure squamous cell carcinoma (SCC), and new treatments are clearly required. Our recent studies have shown that SCC cell lines exhibiting radioresistance show significant upregulation of the fibroblast growth factor receptor 3 (FGFR3) gene. We hypothesized that inhibiting FGFR3 would suppress tumor cell radioresistance and provide a new treatment approach for human SCCs. In the present study, we found that RNA interference-mediated FGFR3 depletion in HSC-2 cells, a radioresistant cell line, induced radiosensitivity and inhibited tumor growth. Use of an FGFR3 inhibitor (PD173074) obtained similar results with suppression of the autophosphorylation extracellular signal-regulated kinase pathway in HSC-2 cells and lung cancer cell lines. Moreover, the antitumor growth effect of the combination of PD173074 and radiation in vivo was also greater than that with either drug alone or radiation alone. Our results provided novel information on which to base further mechanistic study of radiosensitization by inhibiting FGFR3 in human SCC cells and for developing strategies to improve outcomes with concurrent radiotherapy.

Targeting fibroblast-growth-factor-receptor-dependent signaling for cancer therapy

INTRODUCTION

Fibroblast growth factors (FGF) exert a combination of biological effects that contribute to four of the six essential hallmarks of cancer. It is no surprise that FGF-dependent signaling has increasingly moved to the center of cancer therapy research during the past decade. This is illustrated by the large number of publications focusing on various aspects of this theme that have been published in the past 5 years.

AREAS COVERED

Information from these sources as well as ongoing work from the authors' groups is used to outline the physiological functions of FGF signaling and to highlight how the high oncogenic effects of deregulated FGFs and FGFRs derive from their physiological functions. The biological effect of deregulated FGFR signaling in malignant diseases is described and the current state of therapeutic targeting of FGFR is summarized.

EXPERT OPINION

Strategies for targeting FGFR-signaling for cancer therapy are very promising, but need to be carefully developed based on the physiological roles of FGF signaling. Preventive measures may be necessary for protection from FGF-related side effects. Combined targeting of several receptor tyrosine kinases or combination with other therapies may be a useful way of avoiding or ameliorating side effects. FGF-related markers of prognosis and therapy response still need to be investigated.

Novel targeted agents for the treatment of bladder cancer: translating laboratory advances into clinical application

Bladder cancer is a common and frequently lethal cancer. Natural history studies indicate two distinct clinical and molecular entities corresponding to invasive and non-muscle invasive disease. The high frequency of recurrence of noninvasive bladder cancer and poor survival rate of invasive bladder cancer emphasizes the need for novel therapeutic approaches. These mechanisms of tumor development and promotion in bladder cancer are strongly associated with several growth factor pathways including the fibroblast, epidermal, and the vascular endothelial growth factor pathways. In this review, efforts to translate the growing body of basic science research of novel treatments into clinical applications will be explored.

Roles of fibroblast growth factor receptors in carcinogenesis

The fibroblast growth factor receptors (FGFR) play essential roles both during development and in the adult. Upon ligand binding, FGFRs induce intracellular signaling networks that tightly regulate key biological processes, such as cell proliferation, survival, migration, and differentiation. Deregulation of FGFR signaling can thus alter tissue homeostasis and has been associated with several developmental syndromes as well as with many types of cancer. In human cancer, FGFRs have been found to be deregulated by multiple mechanisms, including aberrant expression, mutations, chromosomal rearrangements, and amplifications. In this review, we will give an overview of the main FGFR alterations described in human cancer to date and discuss their contribution to cancer progression.

Bladder cancer: novel molecular characteristics, diagnostic, and therapeutic implications

Bladder cancer (BC) comes in two flavors: as non-muscle invasive (NMI) and as muscle invasive (MI) disease. These two subtypes differ in their genetic aberrations. In NMI-BC mutations in the FGFR3 oncogene are found with a frequency of 75%, whereas mutations in the TP53 tumor suppressor gene prevail in MI-BC. Mutations in the RAS genes occur in 15% of BC of all stages and are mutually exclusive with FGFR3 mutations. Mutations in the PIK3CA gene are found in about 13% and these almost exclusively co-occur with FGFR3 mutations. NMI-BC with FGFR3 mutations are genetically stable, but FGFR3 wild type NMI-BC and MI tumors are genetically unstable. In this paper, we discuss the use of these genetic aberrations in relation to recurrence, progression, surveillance, and therapeutic options. As of yet, there is no biomarker that can predict recurrences or the rate of recurrences when they occur. We show that FGFR3 mutations are associated with a decreased risk of progression, and a better survival both in BC and in upper urinary tract cancer. Microsatellite analysis (MA) in order to detect loss-of-heterozygosity can be used to detect recurrences in urinary cells of patients under surveillance. The results of a Dutch randomized trial show that consecutive positive MA results are a strong predictor for future recurrences. Using FGFR3 mutation analysis for those patients who have an FGFR3 mutant tumor will enhance performance of urine-based surveillance. Although FGFR3 mutations occur in only 20% of MI tumors, these tumors often have a high expression of the FGFR3 protein. This suggests that this receptor could present a target for adjuvant therapy in MI-BC. However, whether the FGFR3 pathway is active in these tumors remains to be established.

Analysis of the fibroblastic growth factor receptor-RAS/RAF/MEK/ERK-ETS2/brachyury signalling pathway in chordomas

Chordomas are rare primary malignant bone tumours that derive from notochord precursor cells and express brachyury, a molecule involved in notochord development. Little is known about the genetic events responsible for driving the growth of this tumour, but it is well established that brachyury is regulated through fibroblastic growth factor receptors (FGFRs) through RAS/RAF/MEK/ERK and ETS2 in ascidian, Xenopus and zebrafish, although little is known about its regulation in mammals. The aim of this study was to attempt to identify the molecular genetic events that are responsible for the pathogenesis of chordomas with particular focus on the FGFR signalling pathway on the basis of the evidence in the ascidian and Xenopus models that the expression of brachyury requires the activation of this pathway. Immunohistochemistry showed that 47 of 50 chordomas (94%) expressed at least one of the FGFRs, and western blotting showed phosphorylation of fibroblast growth factor receptor substrate 2 alpha (FRS2alpha), an adaptor signalling protein, that links FGFR to the RAS/RAF/MEK/ERK pathway. Screening for mutations in brachyury (all coding exons and promoter), FGFRs 1-4 (previously reported mutations), KRAS (codons 12, 13, 51, 61) and BRAF (exons 11 and 15) failed to show any genetic alterations in 23 chordomas. Fluorescent in situ hybridisation analysis on FGFR4, ETS2 and brachyury failed to show either amplification of these genes, although there was minor allelic gain in brachyury in three tumours, or translocation for ERG and ETS2 loci. The key genetic events responsible for the initiation and progression of chordomas remain to be discovered.

The role of fibroblast growth factors in tumor growth

Biological processes that drive cell growth are exciting targets for cancer therapy. The fibroblast growth factor (FGF) signaling network plays a ubiquitous role in normal cell growth, survival, differentiation, and angiogenesis, but has also been implicated in tumor development. Elucidation of the roles and relationships within the diverse FGF family and of their links to tumor growth and progression will be critical in designing new drug therapies to target FGF receptor (FGFR) pathways. Recent studies have shown that FGF can act synergistically with vascular endothelial growth factor (VEGF) to amplify tumor angiogenesis, highlighting that targeting of both the FGF and VEGF pathways may be more efficient in suppressing tumor growth and angiogenesis than targeting either factor alone. In addition, through inducing tumor cell survival, FGF has the potential to overcome chemotherapy resistance highlighting that chemotherapy may be more effective when used in combination with FGF inhibitor therapy. Furthermore, FGFRs have variable activity in promoting angiogenesis, with the FGFR-1 subgroup being associated with tumor progression and the FGFR-2 subgroup being associated with either early tumor development or decreased tumor progression. This review highlights the growing knowledge of FGFs in tumor cell growth and survival, including an overview of FGF intracellular signaling pathways, the role of FGFs in angiogenesis, patterns of FGF and FGFR expression in various tumor types, and the role of FGFs in tumor progression.

A novel strategy based on histological protein profiling in-silico for identifying potential biomarkers in urinary bladder cancer

OBJECTIVE

To screen a publicly available immunohistochemistry (IHC) based web-atlas, to identify key proteins in bladder cancer that might serve as potential biomarkers.

MATERIALS AND METHODS

The first version of the Human Protein Atlas (HPA 1.0), with 660 proteins, was visually examined to identify proteins with a variable staining pattern among the 12 tissue samples representing bladder cancer. None or limited previous characterization in bladder cancer, as well as a supportive Western blot, were also required. The selected proteins were then evaluated in an independent set of patient samples (106 tumour samples of differing stage and grade) represented in a tissue microarray (TMAi). The IHC expression of the identified proteins in the TMAi was scored and related to tumour stage and grade.

RESULTS

The expression profiles of the 13 proteins selected from the web-atlas were confirmed in the TMAi. Expression patterns for seven proteins were significantly altered (P < 0.05) with higher stage and/or grade. Three of those (CN130, DSG3, PHF6) lack characterization in bladder cancer, whereas the remaining four proteins have previously been suggested as key proteins/potential biomarkers in cancer, some of them also in bladder cancer.

CONCLUSION

New candidate proteins for urinary bladder cancer were identified through screening of the publicly available HPA 1.0. Although further evaluation is necessary, this strategy is promising in the search for new biomarkers, with potential to improve the management of patients with this disease.

FGFR3-targeted mAb therapy for bladder cancer and multiple myeloma

Gain-of-function mutations in FGF receptor 3 (FGFR3) have been implicated in severe skeletal dysplasias and in a variety of cancers. In their study in this issue of the JCI, Qing et al. used specific shRNA probes to demonstrate that FGFR3 functions as an important driver of bladder carcinoma cell proliferation (see the related article beginning on page 1216). A unique anti-FGFR3 mAb was shown to exhibit antitumor activity in human bladder carcinoma cells in vitro and in mouse bladder cancer or multiple myeloma xenograft tumor models bearing either wild-type or mutant FGFR3. These results suggest that clinical development of anti-FGFR3 mAbs should be considered for targeted therapy of cancer and other diseases.

Antibody-based targeting of FGFR3 in bladder carcinoma and t(4;14)-positive multiple myeloma in mice

Overexpression of FGF receptor 3 (FGFR3) is implicated in the development of t(4;14)-positive multiple myeloma. While FGFR3 is frequently overexpressed and/or activated through mutations in bladder cancer, the functional importance of FGFR3 and its potential as a specific therapeutic target in this disease have not been elucidated in vivo. Here we report that inducible knockdown of FGFR3 in human bladder carcinoma cells arrested cell-cycle progression in culture and markedly attenuated tumor progression in xenografted mice. Further, we developed a unique antibody (R3Mab) that inhibited not only WT FGFR3, but also various mutants of the receptor, including disulfide-linked cysteine mutants. Biochemical analysis and 2.1-A resolution crystallography revealed that R3Mab bound to a specific FGFR3 epitope that simultaneously blocked ligand binding, prevented receptor dimerization, and induced substantial conformational changes in the receptor. R3Mab exerted potent antitumor activity against bladder carcinoma and t(4;14)-positive multiple myeloma xenografts in mice by antagonizing FGFR3 signaling and eliciting antibody-dependent cell-mediated cytotoxicity (ADCC). These studies provide in vivo evidence demonstrating an oncogenic role of FGFR3 in bladder cancer and support antibody-based targeting of FGFR3 in hematologic and epithelial cancers driven by WT or mutant FGFR3.

Fibroblast growth factor receptor 1-transformed mammary epithelial cells are dependent on RSK activity for growth and survival

Fibroblast growth factor receptor 1 (FGFR1) is frequently amplified and highly expressed in lobular carcinomas of the breast. In this report, we evaluated the biological activity of FGFR1 in a wide range of in vitro assays. Conditional activation of FGFR1 in the nontransformed MCF10A human mammary cell line, MCF10A, resulted in cellular transformation marked by epidermal growth factor-independent cell growth, anchorage-independent cell proliferation and survival, loss of cell polarity, and epithelial-to-mesenchymal transition. Interestingly, small-molecule or small interfering RNA inhibition of ribosomal S6 kinase (RSK) activity induced death of the FGFR1-transformed cells, but not of the parental MCF10A cell line. The dependence of FGFR1-transformed cells on RSK activity was further confirmed in cell lines derived from mouse and human lobular carcinomas that possess high FGFR1 activity. Taken together, these results show the transforming activity of FGFR1 in mammary epithelial cells and identify RSK as a critical component of FGFR1 signaling in lobular carcinomas, thus implicating RSK as a candidate therapeutic target in FGFR1-expressing tumors.

Anti-Inflammatory Agents for Cancer Therapy

Inflammation is closely linked to cancer, and many anti-cancer agents are also used to treat inflammatory diseases, such as rheumatoid arthritis. Moreover, chronic inflammation increases the risk for various cancers, indicating that eliminating inflammation may represent a valid strategy for cancer prevention and therapy. This article explores the relationship between inflammation and cancer with an emphasis on epidemiological evidence, summarizes the current use of anti-inflammatory agents for cancer prevention and therapy, and describes the mechanisms underlying the anti-cancer effects of anti-inflammatory agents. Since monotherapy is generally insufficient for treating cancer, the combined use of anti-inflammatory agents and conventional cancer therapy is also a focal point in discussion. In addition, we also briefly describe future directions that should be explored for anti-cancer anti-inflammatory agents.