DKK1 inhibits canonical Wnt signaling in human papillomavirus-positive penile cancer cells.

Penile squamous cell cancer (PSCC) is the most frequent penile malignant disease. Infections with human papillomaviruses (HPV) are a major etiologic driver of PSCC. However, the molecular details of the underlying carcinogenesis are understudied because of rare clinical specimens and missing cell lines. Here, we investigated if the expression of high-risk HPV16 oncogenes causes an augmentation of the Wnt pathway using unique HPV-positive penile cancer (PeCa) cell lines in monolayer and organotypic 3D raft cultures as well as tissue micro arrays containing clinical tissue specimens. The HPV oncoproteins enhanced the expression of Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) and the HPV-positive PeCa cells expressed a signature of Wnt target and stemness-associated genes. However, the notable lack of nuclear ß-catenin in vitro and in situ raised the question if the enhanced expression of Wnt pathway factors is tantamount to an active Wnt signaling. Subsequent TOP-flash reporter assays revealed Wnt signaling as absent and not inducible by respective Wnt ligands in PeCa cell lines. The HPV-positive PeCa cells and especially HPV-positive PeCa specimens of the tumor core expressed the Wnt antagonist and negative feedback-regulator Dickkopf1 (DKK1). Subsequent neutralization experiments using PeCa cell line-conditioned media demonstrated that DKK1 is capable to impair ligand-induced Wnt signaling. While gene expression analyses suggested an augmented and active canonical Wnt pathway, the respective signaling was inhibited due to the endogenous expression of the antagonist DKK1. Subsequent TMA stainings indicated Dkk1 as linked with HPV-positivity and metastatic disease progression in PeCa suggesting potential as a prognostic marker.

The prominent role of the S100A8/S100A9-CD147 axis in the progression of penile cancer.

Currently, no established biomarkers are recommended for the routine diagnosis of penile carcinoma (PeCa). The rising incidence of this human papillomavirus (HPV)-related cancer entity highlights the need for promising candidates. The Calprotectin subunits S100A8 and S100A9 mark myeloid-derived suppressor cells in other HPV-related entities while their receptor CD147 was discussed to identify patients with PeCa at a higher risk for poor prognoses and treatment failure. We thus examined their expression using immunohistochemistry staining of PeCa specimens from 74 patients on tissue microarrays of the tumor center, the invasion front, and lymph node metastases. Notably, whereas the tumor center was significantly more intensively stained than the invasion front, lymph node metastases were thoroughly positive for both S100 subunits. An HPV-positive status combined with an S100A8+S100A9+ profile was related with an elevated risk for metastases. We observed several PeCa specimens with S100A8+S100A9+-infiltrating immune cells overlapping with CD15 marking neutrophils. The S100A8+S100A9+CD15+ profile was associated with dedifferentiated and metastasizing PeCa, predominantly of HPV-associated subtype. These data suggest a contribution of neutrophil-derived suppressor cells to the progression of HPV-driven penile carcinogenesis. CD147 was elevated, expressed in PeCa specimens, prominently at the tumor center and in HPV-positive PeCa cell lines. CD147+HPV+ PeCa specimens were with the higher-frequency metastasizing cancers. Moreover, an elevated expression of CD147 of HPV-positive PeCa cell lines correlated negatively with the susceptibility to IgA-based neutrophil-mediated tumor cell killing. Finally, stratifying patients regarding their HPV/S100A8/S100A9/CD15/CD147 profile may help identify patients with progressing cancer and tailor immunotherapeutic treatment strategies.

miRNA Expression Characterizes Histological Subtypes and Metastasis in Penile Squamous Cell Carcinoma.

Although microRNAs are described as promising biomarkers in many tumor types, little is known about their role in PSCC. Thus, we attempted to identify miRNAs involved in tumor development and metastasis in distinct histological subtypes considering the impact of HPV infection. In a first step, microarray analyses were performed on RNA from formalin-fixed, paraffin-embedded tumor (22), and normal (8) tissue samples. Microarray data were validated for selected miRNAs by qRT-PCR on an enlarged cohort, including 27 tumor and 18 normal tissues. We found 876 significantly differentially expressed miRNAs (p ≤ 0.01) between HPV-positive and HPV-negative tumor samples by microarray analysis. Although no significant differences were detected between normal and tumor tissue in the whole cohort, specific expression patterns occurred in distinct histological subtypes, such as HPV-negative usual PSCC (95 differentially expressed miRNAs, p ≤ 0.05) and HPV-positive basaloid/warty subtypes (247 differentially expressed miRNAs, p ≤ 0.05). Selected miRNAs were confirmed by qRT-PCR. Furthermore, microarray data revealed 118 miRNAs (p ≤ 0.01) that were significantly differentially expressed in metastatic versus non-metastatic usual PSCC. The lower expression levels for miR-137 and miR-328-3p in metastatic usual PSCC were validated by qRT-PCR. The results of this study confirmed that specific miRNAs could serve as potential diagnostic and prognostic markers in single PSCC subtypes and are associated with HPV-dependent pathways.

The HPV and p63 Status in Penile Cancer Are Linked with the Infiltration and Therapeutic Availability of Neutrophils.

Squamous penile cancer displays a rare human papillomavirus (HPV)-associated tumor entity. Investigations on the molecular pathogenesis of HPV-driven penile cancer are impaired by the rareness of clinical specimens and, in particular, are missing relevant cell culture models. Here, we identified in HPV-positive penile cancer cell lines that HPV16 oncoproteins control TP63 expression by modulating critical regulators, while integration into the TP63 open reading frame facilitates oncogene expression. The resulting feed-forward loop leads to elevated p63 levels that in turn enhance the release of the neutrophil-recruiting chemokine CXCL8. Remarkably, elevated CXCL8 amounts lead to the increased surface exposition of the Fc receptor of human IgA antibodies, FcαRI, on neutrophils and correlated with a higher susceptibility to antibody-dependent neutrophil-mediated cytotoxicity (ADCC) using an EGFR-specific IgA2 antibody. IHC staining of tissue microarrays proved that elevated expression of p63 together with neutrophil infiltration were significantly more frequent in HPV-positive penile cancer displaying a higher tumor grade. In summary, we identified a promising marker profile of patients with penile cancer at higher risk for worse prognosis. However, these patients may benefit from immunotherapeutic approaches efficiently engaging neutrophils for tumor cell killing.

Open-Label, Single-Arm, Phase II Study of Pembrolizumab Monotherapy as First-Line Therapy in Patients With Advanced Non-Clear Cell Renal Cell Carcinoma.

PURPOSE: Programmed death 1 (PD-1) pathway inhibitors have not been prospectively evaluated in patients with non-clear cell renal cell carcinoma (nccRCC). The phase II KEYNOTE-427 study (cohort B) was conducted to assess the efficacy and safety of single-agent pembrolizumab, a PD-1 inhibitor, in advanced nccRCC. METHODS: Patients with histologically confirmed, measurable (Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) nccRCC and no prior systemic therapy received pembrolizumab 200 mg intravenously once every 3 weeks for ≤ 24 months. The primary end point was objective response rate (ORR) per RECIST v1.1. RESULTS: Among enrolled patients (N = 165), 71.5% had confirmed papillary, 12.7% had chromophobe, and 15.8% had unclassified RCC histology. Most patients (67.9%) had intermediate or poor International Metastatic RCC Database Consortium risk status and tumors with programmed death ligand 1 (PD-L1) combined positive score (CPS) ≥ 1 (61.8%). The median time from enrollment to database cutoff was 31.5 months (range, 22.7-38.8). In all patients, the ORR was 26.7%. The median duration of response was 29.0 months; 59.7% of responses lasted ≥ 12 months. The ORR by CPS ≥ 1 and CPS < 1 status was 35.3% and 12.1%, respectively. The ORR by histology was 28.8% for papillary, 9.5% for chromophobe, and 30.8% for unclassified. Overall, the median progression-free survival was 4.2 months (95% CI, 2.9 to 5.6); the 24-month rate was 18.6%. The median overall survival was 28.9 months (95% CI, 24.3 months to not reached); the 24-month rate was 58.4%. Overall, 69.7% of patients reported treatment-related adverse events, most commonly pruritus (20.0%) and hypothyroidism (14.5%). Two deaths were treatment related (pneumonitis and cardiac arrest). CONCLUSION: First-line pembrolizumab monotherapy showed promising antitumor activity in nccRCC. The safety profile was similar to that observed in other tumor types.