PD-L1 as a Urine Biomarker in Renal Cell Carcinoma-A Case Series and Proof-of-Concept Study

BACKGROUND

Renal cell carcinoma (RCC) is among the most lethal urologic malignancies once metastatic. Current treatment approaches for metastatic RCC (mRCC) involve immune checkpoint inhibitors (ICIs) that target the PD-L1/PD-1 axis. High PD-L1 expression in tumor tissue has been identified as a negative prognostic factor in RCC. However, the role of PD-L1 as a liquid biomarker has not yet been fully explored. Herein, we analyze urine levels of PD-L1 in mRCC patients before and after either ICI therapy or surgical intervention, as well as in a series of patients with treatment-naïve RCC.

PATIENTS AND METHODS

The mid-stream urine of patients with mRCC (n = 4) or treatment-naïve RCC, i.e., prior to surgery from two centers (cohort I, n = 49: cohort II, n = 29) was analyzed for PD-L1 by ELISA. The results from cohort I were compared to a control group consisting of patients treated for non-malignant urologic diseases (n = 31). In the mRCC group, urine PD-L1 levels were measured before and after tumor nephrectomy (n = 1) or before and after ICI therapy (n = 3). Exosomal PD-L1 in the urine was analyzed in selected patients by immunoblotting.

RESULTS

A strong decrease in urine PD-L1 levels was found after tumor nephrectomy or following systemic treatment with ICIs. In patients with treatment-naïve RCC (cohort I), urine PD-L1 levels were significantly elevated in the RCC group in comparison to the control group (median 59 pg/mL vs. 25.7 pg/mL, p = 0.011). PD-L1 urine levels were found to be elevated, in particular, in low-grade RCCs in cohorts I and II. Exosomal PD-L1 was detected in the urine of a subset of patients.

CONCLUSION

In this proof-of-concept study, we show that PD-L1 can be detected in the urine of RCC patients. Urine PD-L1 levels were found to correlate with the treatment response in mRCC patients and were significantly elevated in treatment-naïve RCC patients.

Long-Term Survival of Patients with Stage T1N0M1 Renal Cell Carcinoma

Metastatic renal cell carcinoma (RCC) is among the most lethal urological malignancies. However, small, localized RCCs (≤7 cm, stage T1) have an excellent prognosis. There is a rare patient subgroup diagnosed with synchronous distant metastasis (T1N0M1), of which very little is known in terms of survival outcomes and underlying disease biology. Herein, we examined the long-term survival of 27 patients with clear cell RCC (ccRCC) stage T1N0M1 in comparison to 18 patients without metastases (T1N0M0). Tumor tissue was stained by immunohistochemistry for CD8+ tumor infiltrating lymphocytes (TILs). As expected, patients with stage T1N0M1 showed a significantly worse median cancer specific survival (CSS; 2.8 years) than patients with stage T1N0M0 (17.7 years; HR 0.077; 95% CI, 0.022-0.262). However, eight patients (29.6%) with ccRCC stage T1N0M1 survived over five years, and three of those patients (11.1%) survived over a decade. Some of these patients benefitted from an intensified, multimodal treatment including metastasis-directed therapy. The number of CD8+ TILs was substantially higher in stage T1N0M1 ccRCCs than in stage T1N0M0 ccRCCs, suggesting a more aggressive tumor biology. In conclusion, long-term survival is possible in patients with ccRCC stage T1N0M1, with some patients benefitting from an intensified, multimodal treatment approach.

Digital Spatial Profiling Identifies the Tumor Periphery as a Highly Active Biological Niche in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is characterized by a high degree of intratumoral heterogeneity (ITH). Besides genomic ITH, there is considerable functional ITH, which encompasses spatial niches with distinct proliferative and signaling activities. The full extent of functional spatial heterogeneity in ccRCC is incompletely understood. In the present study, a total of 17 ccRCC tissue specimens from different sites (primary tumor, n = 11; local recurrence, n = 1; distant metastasis, n = 5) were analyzed using digital spatial profiling (DSP) of protein expression. A total of 128 regions of interest from the tumor periphery and tumor center were analyzed for the expression of 46 proteins, comprising three major signaling pathways as well as immune cell markers. Results were correlated to clinico-pathological variables. The differential expression of granzyme B was validated using conventional immunohistochemistry and was correlated to the cancer-specific patient survival. We found that a total of 37 proteins were differentially expressed between the tumor periphery and tumor center. Thirty-five of the proteins were upregulated in the tumor periphery compared to the center. These included proteins involved in cell proliferation, MAPK and PI3K/AKT signaling, apoptosis regulation, epithelial-to-mesenchymal transition, as well as immune cell markers. Among the most significantly upregulated proteins in the tumor periphery was granzyme B. Granzyme B upregulation in the tumor periphery correlated with a significantly reduced cancer-specific patient survival. In conclusion, this study highlights the unique cellular contexture of the tumor periphery in ccRCC. The correlation between granzyme B upregulation in the tumor periphery and patient survival suggests local selection pressure for aggressive tumor growth and disease progression. Our results underscore the potential of spatial biology for biomarker discovery in ccRCC and cancer in general.

Senescent Tumor Cells Are Frequently Present at the Invasion Front: Implications for Improving Disease Control in Patients with Locally Advanced Prostate Cancer

INTRODUCTION

Local tumor invasion is a critical factor for the outcome of men with prostate cancer. In particular, seminal vesicle invasion (SVI) has been reported to be associated with a more unfavorable prognosis. A better understanding of the functional state of invading prostate cancer cells is crucial to develop novel therapeutic strategies for patients with locally advanced disease.

METHODS

The prognostic impact of local tumor progression was ascertained in over 1,000 men with prostate cancer. Prostate cancer specimens were stained by double-immunohistochemistry for the proliferation marker Ki-67 and the senescence marker p16INK4A. The migratory properties of senescent prostate cancer cells were analyzed in vitro using a wound healing assay and immunofluorescence microscopy for p16INK4A.

RESULTS

We confirm the notion that patients with SVI have a more unfavorable prognosis than patients with extraprostatic extension alone. Surprisingly, we found that the tumor invasion front frequently harbors p16INK4A-positive and Ki-67-negative, i.e., senescent, tumor cells. While the intraprostatic tumor periphery was a hotspot for both proliferation and expression of p16INK4A, the area of SVI showed less proliferative activity but was at the same time a hotspot of cells with increased nuclear p16INK4A expression. Senescence was associated with an accelerated migration of prostate cancer cells in vitro.

CONCLUSION

This proof-of-concept study shows that invading prostate cancer cells frequently show signs of cellular senescence. This finding may open new avenues for neoadjuvant and adjuvant treatment concepts in men with locally advanced prostate cancer.

Kidney Cancer Models for Pre-Clinical Drug Discovery: Challenges and Opportunities

Renal cell carcinoma (RCC) is among the most lethal urological malignancies once metastatic. The introduction of immune checkpoint inhibitors has revolutionized the therapeutic landscape of metastatic RCC, nevertheless, a significant proportion of patients will experience disease progression. Novel treatment options are therefore still needed and in vitro and in vivo model systems are crucial to ultimately improve disease control. At the same time, RCC is characterized by a number of molecular and functional peculiarities that have the potential to limit the utility of pre-clinical model systems. This includes not only the well-known genomic intratumoral heterogeneity (ITH) of RCC but also a remarkable functional ITH that can be shaped by influences of the tumor microenvironment. Importantly, RCC is among the tumor entities, in which a high number of intratumoral cytotoxic T cells is associated with a poor prognosis. In fact, many of these T cells are exhausted, which represents a major challenge for modeling tumor-immune cell interactions. Lastly, pre-clinical drug development commonly relies on using phenotypic screening of 2D or 3D RCC cell culture models, however, the problem of “reverse engineering” can prevent the identification of the precise mode of action of drug candidates thus impeding their translation to the clinic. In conclusion, a holistic approach to model the complex “ecosystem RCC” will likely require not only a combination of model systems but also an integration of concepts and methods using artificial intelligence to further improve pre-clinical drug discovery.

Interleukin-2 and Interferon-α for Advanced Renal Cell Carcinoma: Patient Outcomes, Sexual Dimorphism of Responses, and Multimodal Treatment Approaches over a 30-Year Period

INTRODUCTION

Cytokine-based immunotherapy (IT) has been the mainstay of systemic treatment of advanced renal cell carcinoma (RCC) from the late 1980s until 2007. With the introduction of immune checkpoint inhibitors, a renaissance of immune oncological approaches is rapidly unfolding.

MATERIALS AND METHODS

In the present study, we revisited survival outcomes, sexual dimorphism of treatment responses, and the relevance of multimodal treatment approaches over a 30-year period in 156 patients with advanced RCC treated with subcutaneous (s.c.) interleukin-2 (IL-2) and interferon-α (IFN-α) between 1990 and 2009.

RESULTS

The median progression-free survival following the first IT was 5.8 months with a wide range from 0 to 197 months. The median overall survival (OS) was 25.8 months and the median cancer-specific survival after tumor nephrectomy was 24.6 months. A group of 29 patients (18.6%) and 11 patients (7.1%) survived longer than 5 and 10 years after surgery, respectively. A difference in the 5-year OS rate between male and female patients was detected (men, 21.6%; women, 11.1%). However, no sex-specific survival advantage was observed after 10 years.

CONCLUSIONS

We provide evidence that IT with s.c. IL-2 and IFN-α played a vital role in long-term survivors either by inducing lasting complete remissions or as part of multimodal approaches that allowed patients to survive until novel therapies became available. The implications for current immune oncological treatment approaches are being discussed.

Mutations in TP53 or DNA damage repair genes define poor prognostic subgroups in primary prostate cancer

BACKGROUND

Mutations in DNA damage repair genes, in particular genes involved in homology-directed repair, define a subgroup of men with prostate cancer with a more unfavorable prognosis but a therapeutic vulnerability to PARP inhibition. In current practice, mutational testing of prostate cancer patients is commonly done late i.e., when the tumor is castration resistant. In addition, most sequencing panels do not include TP53, one of the most crucial tumor suppressor genes in human cancer. In this proof-of-concept study, we sought to extend the clinical use of these molecular markers by exploring the early prognostic impact of mutations in TP53 and DNA damage repair genes in men with primary, nonmetastatic prostate cancer undergoing radical prostatectomy (RPX).

METHODS

Tumor specimens from a cohort of 68 RPX patients with intermediate (n = 11, 16.2%) or high-risk (n = 57, 83.8%) disease were analyzed by targeted next generation sequencing using a 37 DNA damage repair and checkpoint gene panel including TP53. Sequencing results were correlated to clinicopathologic variables as well as PSA persistence or time to PSA failure. In addition, the distribution of TP53 and DNA damage repair gene mutations was analyzed in three large publicly available datasets (TCGA, MSKCC and SU2C).

RESULTS

Of 68 primary prostate cancers analyzed, 23 (33.8%) were found to harbor a mutation in either TP53 (n = 12, 17.6%) or a DNA damage repair gene (n = 11, 16.2%). The vast majority of these mutations (22 of 23, 95.7%) were detected in primary tumors from patients with high-risk features. These mutations were mutually exclusive in our cohort and additional data mining suggests an enrichment of DNA damage repair gene mutations in TP53 wild-type tumors. Mutations in either TP53 or a DNA damage repair gene were associated with a significantly worse prognosis after RPX. Importantly, the presence of TP53/DNA damage repair gene mutations was an independent risk factor for PSA failure or PSA persistence in multivariate Cox regression models.

CONCLUSION

TP53 or DNA damage repair gene mutations are frequently detected in primary prostate cancer with high-risk features and define a subgroup of patients with an increased risk for PSA failure or persistence after RPX. The significant adverse impact of these alterations on patient prognosis may be exploited to identify men with prostate cancer who may benefit from a more intensified treatment.

Detection of PD-L1 in the urine of patients with urothelial carcinoma of the bladder

There are currently five programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors approved for the treatment of locally advanced or metastatic urothelial carcinoma (UC) of the bladder. For platinum-ineligible patients, testing of tumor specimens for PD-L1 expression is required. However, scoring of PD-L1 immunohistochemistry is complex due to different antibodies used, the requirement to score expression in different cellular compartments and intratumoral heterogeneity. It can also be difficult to obtain and test longitudinal tumor samples, which would be desirable to monitor treatment responses and tumor evolution under treatment-induced selective pressure. In the present proof-of concept study, we provide evidence that PD-L1 can be detected in the urine of patients with non-muscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Urine PD-L1 levels were significantly higher in NMIBC and MIBC patients when compared to patients with various non-malignant urological diseases. Further prospective and independent studies are required to assess the value of PD-L1 in the urine as a novel biomarker with potential for the early detection, prediction and therapeutic monitoring of patients with UC of the bladder.

Targeting the Proteasome in Advanced Renal Cell Carcinoma: Complexity and Limitations of Patient-Individualized Preclinical Drug Discovery

Background: Systemic treatment options for metastatic renal cell carcinoma (RCC) have significantly expanded in recent years. However, patients refractory to tyrosine kinase and immune checkpoint inhibitors still have limited treatment options and patient-individualized approaches are largely missing. Patients and Methods: In vitro drug screening of tumor-derived short-term cultures obtained from seven patients with clear cell RCC was performed. For one patient, a patient-derived xenograft (PDX) mouse model was established for in vivo validation experiments. Drug effects were further investigated in established RCC cell lines. Results: The proteasome inhibitor carfilzomib was among the top hits identified in three of four patients in which an in vitro drug screening could be performed successfully. Carfilzomib also showed significant acute and long-term cytotoxicity in established RCC cell lines. The in vivo antitumoral activity of carfilzomib was confirmed in a same-patient PDX model. The cytotoxicity of carfilzomib was found to correlate with the level of accumulation of ubiquitinated proteins. Conclusions: In this proof-of-concept study, we show that patient-individualized in vitro drug screening and preclinical validation is feasible. However, the fact that carfilzomib failed to deliver a clinical benefit in RCC patients in a recent phase II trial unrelated to the present study underscores the complexities and limitations of this strategy.

miR-449a Repression Leads to Enhanced NOTCH Signaling in TMPRSS2:ERG Fusion Positive Prostate Cancer Cells

About 50% of prostate cancer (PCa) tumors are TMPRSS2:ERG (T2E) fusion-positive (T2E+), but the role of T2E in PCa progression is not fully understood. We were interested in investigating epigenomic alterations associated with T2E+ PCa. Using different sequencing cohorts, we found several transcripts of the miR-449 cluster to be repressed in T2E+ PCa. This repression correlated strongly with enhanced expression of NOTCH and several of its target genes in TCGA and ICGC PCa RNA-seq data. We corroborated these findings using a cellular model with inducible T2E expression. Overexpression of miR-449a in vitro led to silencing of genes associated with NOTCH signaling (NOTCH1, HES1) and HDAC1. Interestingly, HDAC1 overexpression led to the repression of HES6, a negative regulator of the transcription factor HES1, the primary effector of NOTCH signaling, and promoted cell proliferation by repressing the cell cycle inhibitor p21. Inhibition of NOTCH as well as knockdown of HES1 reduced the oncogenic properties of PCa cell lines. Using tissue microarray analysis encompassing 533 human PCa cores, ERG-positive areas exhibited significantly increased HES1 expression. Taken together, our data suggest that an epigenomic regulatory network enhances NOTCH signaling and thereby contributes to the oncogenic properties of T2E+ PCa.

Actin-binding protein profilin1 promotes aggressiveness of clear-cell renal cell carcinoma cells

Clear-cell renal cell carcinoma (ccRCC), the most common subtype of renal cancer, has a poor clinical outcome. A hallmark of ccRCC is genetic loss-of-function of VHL (von Hippel-Lindau) that leads to a highly vascularized tumor microenvironment. Although many ccRCC patients initially respond to antiangiogenic therapies, virtually all develop progressive, drug-refractory disease. Given the role of dysregulated expressions of cytoskeletal and cytoskeleton-regulatory proteins in tumor progression, we performed analyses of The Cancer Genome Atlas (TCGA) transcriptome data for different classes of actin-binding proteins to demonstrate that increased mRNA expression of profilin1 (Pfn1), Arp3, cofilin1, Ena/VASP, and CapZ, is an indicator of poor prognosis in ccRCC. Focusing further on Pfn1, we performed immunohistochemistry-based classification of Pfn1 staining in tissue microarrays, which indicated Pfn1 positivity in both tumor and stromal cells; however, the vast majority of ccRCC tumors tend to be Pfn1-positive selectively in stromal cells only. This finding is further supported by evidence for dramatic transcriptional up-regulation of Pfn1 in tumor-associated vascular endothelial cells in the clinical specimens of ccRCC. In vitro studies support the importance of Pfn1 in proliferation and migration of RCC cells and in soluble Pfn1's involvement in vascular endothelial cell tumor cell cross-talk. Furthermore, proof-of-concept studies demonstrate that treatment with a novel computationally designed Pfn1-actin interaction inhibitor identified herein reduces proliferation and migration of RCC cells in vitro and RCC tumor growth in vivo Based on these findings, we propose a potentiating role for Pfn1 in promoting tumor cell aggressiveness in the setting of ccRCC.

Rearranged ERG confers robustness to prostate cancer cells by subverting the function of p53

OBJECTIVE

ERG rearrangements are frequent and early events in prostate cancer. The functional role of rearranged ERG, however, is still incompletely understood. ERG rearrangements are maintained during prostate cancer progression suggesting that they may confer a selective advantage. The molecular basis of this notion is the subject of this study.

METHODS

A variety of immunological methods were used to characterize the effects of rearranged ERG on p53. Consequences of an overexpression of N-terminally deleted ERG on p53 function were interrogated by measuring apoptosis and cellular senescence in the presence or absence of exogenous DNA damage. Effects of N-terminally deleted ERG on the transactivation function of p53 were analyzed by qRT-PCR.

RESULTS

We show that overexpression of ERG leads to an increased basal level of DNA damage and a stabilization of p53 that involves a sequestration of its E3 ubiquitin ligase, MDM2, into nucleoli. A higher p53 expression was also observed in vivo in an ERG-overexpressing prostatic intraepithelial neoplasia mouse model. The correlation between ERG and p53 expression was corroborated in 163 patients with prostate cancer. ERG overexpression was found to inhibit both apoptosis and cellular senescence induced by exogenous DNA damage. Mechanistically, this protective effect of ERG involved an abrogation of the DNA damage-induced expression of p53 target genes.

CONCLUSIONS

By protecting tumor cells from the antiproliferative consequences of genotoxic stress, ERG may allow the survival and proliferation of genomically unstable tumor cells. Targeting ERG may therefore represent a promising strategy to suppress such adverse features during prostate cancer progression.

Antibody selection influences the detection of AR-V7 in primary prostate cancer

BACKGROUND

The androgen receptor (AR) splice variant V7 (AR-V7) is an emerging marker to aid clinical decision-making in patients with castration-resistant prostate cancer (CRPC). A number of studies have shown that a subset of patients also express AR-V7 in the primary tumor. These findings have recently been challenged by a study showing that AR-V7 becomes only detectable in CRPC but is virtually absent in castration-naïve prostate cancer.

METHODS

Herein, we directly compare the two relevant antibodies used for the immunodetection of AR-V7 in the conflicting studies (clones AG10008 and RM7) in a predominantly high-risk prostate cancer patient cohort with primary tumor specimens assembled in a tissue microarray (TMA).

RESULTS

The overall rate of AR-V7 positive TMA cores was comparable (AG10008, 24.9%; RM7, 21%). However, the percentage agreement of identical staining intensities of positive cores was only 7%. In contrast, the percentage agreement of negative cores was 62.8%. In approximately 30% of the cores, the antibodies produced discordant staining intensities. Only one of the two antibody stainings (AG10008) conveyed prognostic information and was associated with a shorter progression-free patient survival.

CONCLUSIONS

Our study underscores that nuclear AR-V7 expression can be detected in primary prostate cancer prior to long-term androgen deprivation and castration resistance. There are staining differences between the two antibodies in tumor tissue, for which we currently have no explanation. Clearly, improvements in the detection of functional AR-V7 in prostate cancer are urgently needed.

Microenvironment-Derived FGF-2 Stimulates Renal Cell Carcinoma Cell Proliferation through Modulation of p27Kip1: Implications for Spatial Niche Formation and Functional Intratumoral Heterogeneity

BACKGROUND/OBJECTIVE

Clear cell renal cell carcinoma (ccRCC) is characterized by a high degree of functional intratumoral heterogeneity (ITH). This is highlighted by the finding that tumor cell proliferation and intracellular signaling occur preferentially in the tumor periphery. The driving forces for such a spatial organization are largely unknown. Herein, we investigate the role of the tumor microenvironment in the control of tumor cell proliferation and functional ITH.

METHODS

Conditioned media (CM) derived from nonmalignant peritumoral kidney tissue were used to stimulate RCC cells in vitro. A neutralization assay was used to characterize the role of FGF-2 in the CM. The molecular mechanisms underlying the action of CM on RCC cells were investigated using immunoblotting, flow cytometry and immunofluorescence microscopy. Lastly, a series of ccRCCs were stained for Ki-67 and p27Kip1, and expression was analyzed in both tumor periphery and center.

RESULTS

We show that CM derived from nonmalignant kidney cells adjacent to an RCC can downregulate the expression of the CDK inhibitor p27Kip1 through enhanced protein degradation in an FGF-2-dependent fashion. FGF-2 functions mainly through the PI3K/AKT pathway downstream of its receptors, and RCC cells with constitutively high AKT activity show not only an enhanced degradation of p27Kip1 through the Emi1-Skp2 axis, but also a subcellular mislocalization of p27Kip1 to the cytoplasmic compartment. Such a mislocalization was also detected in the tumor periphery in vivo suggesting that p27Kip1 plays an important role in shaping this spatial niche.

CONCLUSIONS

Our results suggest that the tumor microenvironment is involved in shaping the tumor peripheral niche by stimulating the enhanced proliferation that is characteristic for this zone.

The BRCA2 mutation status shapes the immune phenotype of prostate cancer

Defects in DNA damage repair caused by mutations in BRCA1/2, ATM or other genes have been shown to play an important role in the development and progression of prostate cancer. The influence of such mutations on anti-tumor immunity in prostate cancer, however, is largely unknown. To better understand the correlation between BRCA1/2 mutations and the immune phenotype in prostate cancer, we characterized the immune infiltrate of eight BRCA2-mutated tumors in comparison with eight BRCA1/2 wild-type patients by T-cell receptor sequencing and immunohistochemistry for CD45, CD4, CD8, FOXP3, and CD163. In addition, we analyzed seven prostate cancer biopsies that were either BRCA2 or ATM-mutated in comparison with wild-type tumors. Whereas in BRCA1/2 wild-type tumors, immune cells were found predominantly extratumorally, most BRCA2-mutated tumors including one biopsy showed a significantly increased intratumoral immune cell infiltration. The ratio of intratumoral to extratumoral immune cells was considerably higher in BRCA2-mutated tumors for all markers and reached statistical significance for CD4 (p = 0.007), CD8 (p = 0.006), and FOXP3 (p = 0.001). However, the intratumoral CD8 to FOXP3 ratio showed a trend to be lower in BRCA2-mutated tumors suggesting a more suppressed tumor immune microenvironment. Our findings provide a rationale for the future use of immune oncological approaches in BRCA2-mutated prostate cancer and may encourage efforts to target immunosuppressive T-cell populations to prime tumors for immunotherapy.

FGF-2 is a driving force for chromosomal instability and a stromal factor associated with adverse clinico-pathological features in prostate cancer

BACKGROUND

There is mounting evidence to suggest that stromal cells play an integral role in the progression of prostate cancer (PCa). One of the most frequently altered growth factors in PCa is fibroblast growth factor-2 (FGF-2). It has previously been proposed that early stages of PCa are characterized by a primarily exogenous, that is, stromal cell-derived FGF-2 production, whereas advanced tumors rely more on an autocrine FGF-2 production. Prostate cancer progression is characterized by an increase of genomic instability including aneuploidy and structural chromosomal alterations. Herein, we address 2 problems that have not been comprehensively answered. First, we ask whether exogenous FGF-2 can directly drive genomic instability to promote PCa progression. Second, we investigate whether and to what extent stromal FGF-2 expression is maintained in advanced PCa and whether this influences tumor progression and patient prognosis.

METHODS

In vitro experiments to investigate the role of FGF-2 in numerical and structural chromosomal instability were performed using immunofluorescence microscopy, fluorescence in situ hybridization and single cell electrophoresis. A human patient-derived xenograft mouse model recapitulating osteoblastic PCa bone metastasis was used for in vivo validation experiments. The prognostic role of stromal FGF-2 expression was analyzed using immunohistochemical staining of a tissue microarray with primary tumor specimens from 162 predominantly high-risk patients with PCa.

RESULTS

Our results show that FGF-2 not only rapidly induces mitotic defects and numerical chromosomal imbalances but also an enhanced DNA breakage to promote chromosomal instability. Using the patient-derived xenograft model, we show that a deregulation of the FGF axis results in an increase of mitotic aberrations as well as DNA damage checkpoint activation in vivo. The FGFR inhibitor dovitinib was found to reduce numerical chromosomal instability as well as DNA breakage, thus underscoring the relevance of the FGF axis in promoting genomic instability. An overexpression of tumor cell-associated FGF-2 was detected in 52 of 162 patients (32.1%), whereas a stromal overexpression was found in 27 of 165 patients (16%). Remarkably, a strong stromal FGF-2 expression was associated with a significantly higher clinical stage and higher biochemical recurrence rate. Patients with strong stromal FGF-2 expression also had a significantly worse biochemical recurrence-free survival.

CONCLUSIONS

Our results underscore that exogenous FGF-2 can shape PCa cell genomes and that stromal FGF-2 expression is detectable in a sizeable proportion of advanced PCa where it is associated with adverse clinico-pathological features. Our results highlight the impact of the tumor stroma on malignant progression and provide a rationale for a further exploration of components of the tumor stroma as therapeutic targets in PCa.

APOBEC3A Expression in Penile Squamous Cell Carcinoma

BACKGROUND

APOBECs (apolipoprotein B mRNA-editing catalytic polypeptides) are cytidine deaminases that have been implicated in the host defense against viruses by blocking viral replication. They have also been shown to play a role in genome hypermutation in several human cancers. An APOBEC3 hypermutation signature has been discovered in cervical cancer, which is intimately associated with infection by high-risk human papillomaviruses (HPVs). At the same time, HPV genomes themselves are subject to DNA editing by APOBECs. Similar to cervical cancer, a proportion of penile squamous cell carcinomas (SCCs) is etiologically driven by high-risk HPVs, but very little is known about the role of APOBECs in penile SCC development and progression.

METHODS

A series of 34 penile SCCs was analyzed for the expression of APOBEC3A protein by immunohistochemistry. HPV genotyping was carried out using a bead-based multiplex hybridization assay preceded by BSGP5+6+ primer-based amplification.

RESULTS

We found a frequent reduction of APOBEC3A protein expression in the invasive parts of the majority of HPV-negative penile SCCs. In contrast, the majority of HPV-positive penile SCCs retained APOBEC3A expression during malignant progression.

CONCLUSION

Our results suggest that APOBEC3A expression is downregulated during progression towards invasiveness in HPV-negative penile SCC, but maintained in HPV-positive penile SCC. How high-risk HPV-infected tumor cells tolerate high APOBEC3A, which appears to exert tumor suppressive functions in HPV-negative penile SCCs, remains to be elucidated.

Delivery of improved oncolytic adenoviruses by mesenchymal stromal cells for elimination of tumorigenic pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies and has poor therapeutic options. We evaluated improved oncolytic adenoviruses (OAds), in which the adenoviral gene E1B19K was deleted or a TRAIL transgene was inserted. Bone marrow mesenchymal stromal cells (MSCs) served as carriers for protected and tumor-specific virus transfers. The infection competence, tumor migration, and oncolysis were measured in cancer stem cell (CSC) models of primary and established tumor cells and in tumor xenografts. All OAds infected and lysed CSCs and prevented colony formation. MSCs migrated into PDA spheroids without impaired homing capacity. Xenotransplantation of non-infected PDA cells mixed with infected tumor cells strongly reduced the tumor volume and the expression of the proliferation marker Ki67 along with a necrotic morphology. Adenoviral capsid protein was detected in tumor xenograft tissue after intravenous injection of infected MSCs, but not in normal tissue, implying tumor-specific migration. Likewise, direct in vivo treatment correlated with a strongly reduced tumor volume, lower expression of Ki67 and CD24, and enhanced activity of caspase 3. These data demonstrate that the improved OAds induced efficient oncolysis with the OAd-TRAIL as most promising candidate for future clinical application.

Sulforaphane, quercetin and catechins complement each other in elimination of advanced pancreatic cancer by miR-let-7 induction and K-ras inhibition

Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis of all malignancies, and current therapeutic options do not target cancer stem cells (CSCs), which may be the reason for the extreme aggressiveness. The dietary agents sulforaphane and quercetin enriched e.g., in broccoli, and the main and best studied green tea catechin EGCG hold promise as anti-CSC agents in PDA. We examined the efficacy of additional catechins and the combination of these bioactive agents to stem cell features and miRNA signaling. Two established and one primary PDA cell line and non-malignant pancreatic ductal cells were used. Whereas each agent strongly inhibited colony formation, the catechins ECG and CG were more effective than EGCG. A mixture of green tea catechins (GTCs) significantly inhibited viability, migration, expression of MMP-2 and -9, ALDH1 activity, colony and spheroid formation and induced apoptosis, but the combination of GTCs with sulforaphane or quercetin was superior. Following treatment with bioactive agents, the expression of miR-let7-a was specifically induced in cancer cells but not in normal cells and it was associated with K-ras inhibition. These data demonstrate that sulforaphane, quercetin and GTC complement each other in inhibition of PDA progression by induction of miR-let7-a and inhibition of K-ras.

Autophagy mediates survival of pancreatic tumour-initiating cells in a hypoxic microenvironment

Involvement of dysregulated autophagy in cancer growth and progression has been shown in different tumour entities, including pancreatic ductal adenocarcinoma (PDA). PDA is an extremely aggressive tumour characterized by a small population of highly therapy-resistant cancer stem cells (CSCs) capable of self-renewal and migration. We examined whether autophagy might be involved in the survival of CSCs despite nutrition and oxygen deprivation typical for the hypoxic tumour microenvironment of PDA. Immunohistochemistry revealed that markers for hypoxia, CSCs and autophagy are co-expressed in patient-derived tissue of PDA. Hypoxia starvation (H/S) enhanced clonogenic survival and migration of established pancreatic cancer cells with stem-like properties (CSC(high)), while pancreatic tumour cells with fewer stem cell markers (CSC(low)) did not survive these conditions. Electron microscopy revealed more advanced autophagic vesicles in CSC(high) cells, which exhibited higher expression of autophagy-related genes under normoxic conditions and relative to CSC(low) cells, as found by RT-PCR and western blot analysis. LC3 was already fully converted to the active LC3-II form in both cell lines, as evaluated by western blot and detection of accumulated GFP-LC3 protein by fluorescence microscopy. H/S increased formation of autophagic and acid vesicles, as well as expression of autophagy-related genes, to a higher extent in CSC(high) cells. Modulation of autophagy by inhibitors and activators resensitized CSC(high) to apoptosis and diminished clonogenicity, spheroid formation, expression of CSC-related genes, migratory activity and tumourigenicity in mice. Our data suggest that enhanced autophagy levels may enable survival of CSC(high) cells under H/S. Interference with autophagy-activating or -inhibiting drugs disturbs the fine-tuned physiological balance of enhanced autophagy in CSC and switches survival signalling to suicide.

Identification of a subpopulation of cells with cancer stem cell properties in head and neck squamous cell carcinoma

Like many epithelial tumors, head and neck squamous cell carcinoma (HNSCC) contains a heterogeneous population of cancer cells. We developed an immunodeficient mouse model to test the tumorigenic potential of different populations of cancer cells derived from primary, unmanipulated human HNSCC samples. We show that a minority population of CD44(+) cancer cells, which typically comprise <10% of the cells in a HNSCC tumor, but not the CD44(-) cancer cells, gave rise to new tumors in vivo. Immunohistochemistry revealed that the CD44(+) cancer cells have a primitive cellular morphology and costain with the basal cell marker Cytokeratin 5/14, whereas the CD44(-) cancer cells resemble differentiated squamous epithelium and express the differentiation marker Involucrin. The tumors that arose from purified CD44(+) cells reproduced the original tumor heterogeneity and could be serially passaged, thus demonstrating the two defining properties of stem cells: ability to self-renew and to differentiate. Furthermore, the tumorigenic CD44(+) cells differentially express the BMI1 gene, at both the RNA and protein levels. By immunohistochemical analysis, the CD44(+) cells in the tumor express high levels of nuclear BMI1, and are arrayed in characteristic tumor microdomains. BMI1 has been demonstrated to play a role in self-renewal in other stem cell types and to be involved in tumorigenesis. Taken together, these data demonstrate that cells within the CD44(+) population of human HNSCC possess the unique properties of cancer stem cells in functional assays for cancer stem cell self-renewal and differentiation and form unique histological microdomains that may aid in cancer diagnosis.

[Analysis of mean differences for acid-base balance parameters in blood from umbilical arteries and veins of newborns with perinatal hypoxemia]

Arterio-venous differences in acid-base parameters of umbilical vessels blood using Nickelsen and Weber method and SPSS/PC+ computer's program were calculated. The mean differences are dependent on fetal metabolism, umbilical blood flow and placental gas exchange. Arterio-venous differences--normal or increased for pH, PCO2, PO2 and SO2 are valuable diagnostic indicators of accurate gas exchange while decreased values of these differences should predict placental dysfunction. Small differences are signs of chronic fetus hypoxaemia originated by anaerobic metabolism and increased the fetal lactic acid production, respectively.