PGE2 expression by HPV6/11-induced respiratory papillomas blocks NK cell activation in patients with recurrent respiratory papillomatosis.

Recurrent respiratory papillomatosis (RRP), a rare chronic disease caused primarily by human papillomavirus types 6 and 11, consists of repeated growth of premalignant papillomas in the airway. RRP is characterized by multiple abnormalities in innate and adaptive immunity. Natural killer (NK) cells play important roles in immune surveillance and are part of the innate immune responses that help prevent tumor growth. We identified that papillomas lack classical class I MHC and retain nonclassical class I MHC expression. Moreover, in this study, we have identified and characterized the mechanism that blocks NK cell targeting of papilloma cells. Here, we show for the first time that the PGE2 secreted by papilloma cells directly inhibits NK cells activation/degranulation principally through the PGE2 receptor EP2, and to a lesser extent through EP4 signaling. Thus, papilloma cells have a potent mechanism to block NK cell function that likely supports papilloma cell growth.

Pharmacological prevention of surgery-accelerated metastasis in an animal model of osteosarcoma.

BACKGROUND: Osteosarcoma is a highly metastatic primary bone tumor that predominantly affects adolescents and young adults. A mainstay of treatment in osteosarcoma is removal of the primary tumor. However, surgical excision itself has been implicated in promoting tumor growth and metastasis, an effect known as surgery-accelerated metastasis. The underlying mechanisms contributing to surgery-accelerated metastasis remain poorly understood, but pro-tumorigenic alterations in macrophage function have been implicated. METHODS: The K7M2-BALB/c syngeneic murine model of osteosarcoma was used to study the effect of surgery on metastasis, macrophage phenotype, and overall survival. Pharmacological prevention of surgery-accelerated metastasis was examined utilizing gefitinib, a receptor interacting protein kinase 2 inhibitor previously shown to promote anti-tumor macrophage phenotype. RESULTS: Surgical excision of the primary tumor resulted in increases in lung metastatic surface nodules, overall metastatic burden and number of micrometastatic foci. This post-surgical metastatic enhancement was associated with a shift in macrophage phenotype within the lung to a more pro-tumor state. Treatment with gefitinib prevented tumor-supportive alterations in macrophage phenotype and resulted in reduced metastasis. Removal of the primary tumor coupled with gefitinib treatment resulted in enhanced median and overall survival. CONCLUSIONS: Surgery-accelerated metastasis is mediated in part through tumor supportive alterations in macrophage phenotype. Targeted pharmacologic therapies that prevent pro-tumor changes in macrophage phenotype could be utilized perioperatively to mitigate surgery-accelerated metastasis and improve the therapeutic benefits of surgery.

Intratibial Injection Causes Direct Pulmonary Seeding of Osteosarcoma Cells and Is Not a Spontaneous Model of Metastasis: A Mouse Osteosarcoma Model.

BACKGROUND: Although metastasis is the major cause of mortality in patients with osteosarcoma, little is known about how micrometastases progress to gross metastatic disease. Clinically relevant animal models are necessary to facilitate development of new therapies to target indolent pulmonary metastases. Intratibial injection of human and murine osteosarcoma cell lines have been described as orthotopic models that develop spontaneous pulmonary metastasis over time. However, there is variability in reported injection techniques and metastatic efficiency. QUESTIONS/PURPOSES: We aimed to characterize a widely used murine model of metastatic osteosarcoma, determine whether it is appropriate to study spontaneous pulmonary metastasis by establishing a reliable volume for intratibial injection, determine the incidence of primary tumor and metastatic formation, determine the kinetics of pulmonary metastatic seeding and outgrowth, and the contribution of the primary tumor to subsequent development of metastasis. METHODS: The metastatic mouse osteosarcoma cell line K7M2 was injected into the tibia of mice. The maximum volume that could be injected without leakage was determined using Evan's blue dye (n = 8 mice). Primary tumor formation and metastatic efficiency were determined by measuring the incidence of primary tumor and metastatic formation 4 weeks after intratibial injection (n = 30). The kinetics of metastatic development were determined by performing serial euthanasia at 1, 2, 3, and 4 weeks after injection (n = 24; five to six mice per group). Number of metastatic foci/histologic lung section and metastatic burden/lung section (average surface area of metastatic lesions divided by the total surface area of the lung) was calculated in a blinded fashion. To test the contribution of the primary tumor to subsequent metastases, amputations were performed 30 minutes, 4 hours, or 24 hours after injection (n = 21; five to six mice per group). Mice were euthanized after 4 weeks and metastatic burden calculated as described previously, comparing mice that had undergone amputation with control, nonamputated mice. Differences between groups were calculated using Kruskal-Wallis and one-way analysis of variance. RESULTS: The maximum volume of cell suspension that could be injected without leakage was 10 µL. Intratibial injection of tumor cells led to intramedullary tumor formation in 93% of mice by 4 weeks and resulted in detectable pulmonary metastases in 100% of these mice as early as 1 week post-injection. Metastatic burden increased over time (0.88% ± 0.58, week 1; 6.6% ± 5.3, week 2; 16.1% ± 12.5, week 3; and 40.3% ± 14.83, week 4) with a mean difference from week 1 to week 4 of -39.38 (p < 0.001; 95% confidence interval [CI], -57.39 to -21.37), showing pulmonary metastatic growth over time. In contrast, the mean number of metastatic foci did not increase from week 1 to week 4 (36.4 ± 33.6 versus 49.3 ± 26.3, p = 0.18). Amputation of the injected limb at 30 minutes, 4 hours, and 24 hours after injection did not affect pulmonary metastatic burden at 4 weeks, with amputation as early as 30 minutes post-injection resulting in a metastatic burden equivalent to tumor-bearing controls (48.9% ± 6.1% versus 40.9% ± 15.3%, mean difference 7.96, p = 0.819; 95% CI, -33.9 to 18.0). CONCLUSIONS: There is immediate seeding of the metastatic site after intratibial injection of the K7M2 osteosarcoma cell line, independent of a primary tumor. This is therefore not a model of spontaneous metastasis. CLINICAL RELEVANCE: This model should not be used to study the early components of the metastatic cascade, but rather used as an experimental model of metastasis. Improved understanding of this commonly used model will allow for proper interpretation of existing data and inform the design of future studies exploring the biology of metastasis in osteosarcoma.

HMGB1 Mediates Anemia of Inflammation in Murine Sepsis Survivors.

Patients surviving sepsis develop anemia, but the molecular mechanism is unknown. Here we observed that mice surviving polymicrobial gram-negative sepsis develop hypochromic, microcytic anemia with reticulocytosis. The bone marrow of sepsis survivors accumulates polychromatophilic and orthochromatic erythroblasts. Compensatory extramedullary erythropoiesis in the spleen is defective during terminal differentiation. Circulating tumor necrosis factor (TNF) and interleukin (IL)-6 are elevated for 5 d after the onset of sepsis, and serum high-mobility group box 1 (HMGB1) levels are increased from d 7 until at least d 28. Administration of recombinant HMGB1 to healthy mice mediates anemia with extramedullary erythropoiesis and significantly elevated reticulocyte counts. Moreover, administration of anti-HMGB1 monoclonal antibodies after sepsis significantly ameliorates the development of anemia (hematocrit 48.5 ± 9.0% versus 37.4 ± 6.1%, p < 0.01; hemoglobin 14.0 ± 1.7 versus 11.7 ± 1.2 g/dL, p < 0.01). Together, these results indicate that HMGB1 mediates anemia by interfering with erythropoiesis, suggesting a potential therapeutic strategy for anemia in sepsis.

Celecoxib inhibits Ewing sarcoma cell migration via actin modulation.

BACKGROUND: Ewing sarcoma (ES) is an aggressive childhood solid tumor in which 30% of cases are metastatic at presentation, and subsequently carry a poor prognosis. We have previously shown that treatment with celecoxib significantly reduces invasion and metastasis of ES cells in a cyclooxygenase-2-independent fashion. Celecoxib is known to downregulate ß-catenin independently of cyclooxygenase-2. Additionally, the actin cytoskeleton is known to play an important role in tumor micrometastasis. We hypothesized that celecoxib's antimetastatic effect in ES acts via modulation of one of these two targets. METHODS: ES cells were treated with celecoxib, and the levels of ß-catenin and total actin were examined by Western blot and quantitative polymerase chain reaction. Cells were transfected with small interfering RNA targeting ß-catenin, and invasion assays were performed. Immunofluorescence staining for ß-catenin and F-actin was performed on treated and untreated cells. Additionally, cells were subjected to a wound healing assay to assess migration. RESULTS: Celecoxib had no effect on the messenger RNA or protein levels of ß-catenin but did significantly decrease the amount of total actin within ES cells. Reduction of ß-catenin by small interfering RNA had no effect on invasion, and celecoxib treatment of the ß-catenin depleted cells continued to inhibit invasion. Immunofluorescence staining demonstrated no change in ß-catenin with treatment but did show a significant reduction in the amount of F-actin, as well as morphologic changes of the cells. Wound healing assays demonstrated that celecoxib significantly inhibited migration. CONCLUSIONS: Celecoxib does not exert its antimetastatic effects in ES through alteration of ß-catenin but does significantly modulate the actin cytoskeleton.

Papillomavirus-specific CD4+ T cells exhibit reduced STAT-5 signaling and altered cytokine profiles in patients with recurrent respiratory papillomatosis.

Recurrent respiratory papillomatosis (RRP) is caused by human papillomavirus type 6 (HPV-6) or HPV-11. Specific HLA-DR haplotypes DRB1*01:02 and DRB1*03:01 are associated with the development of RRP, disease severity, and Th2-like responses to HPV early proteins. Th1-like responses to HPV proteins have been shown to be protective in animal models. Therefore, we investigated the hypothesis that RRP patients have dysfunctional Th1-like, HPV-specific T cell responses. Using MHC class II tetramers, we identified immunogenic peptides within HPV-11 early proteins. Two distinct peptides (E6(113-132) and E2(1-20)) contained DRB1*01:02- or DRB1*03:01-restricted epitopes, respectively. An additional peptide (E2(281-300)) contained an epitope presented by both alleles. Peptide binding, tetramer, and proliferation assays identified minimal epitopes within these peptides. These epitopes elicited E2/E6-specific CD4(+) T cell responses in RRP patients and healthy control subjects, allowing the isolation of HPV-specific T cell lines using tetramers. The cytokine profiles and STAT signaling of these tetramer-positive T cells were measured to compare the polarization and responsiveness of HPV-specific T cells from patients with RRP and healthy subjects. HPV-specific IFN-γ secretion was substantially lower in T cells from RRP patients. HPV-specific IL-13 secretion was seen at modest levels in T cells from RRP patients and was absent in T cells from healthy control subjects. HPV-specific T cells from RRP patients exhibited reduced STAT-5 phosphorylation and reduced IL-2 secretion, suggesting anergy. Levels of STAT-5 phosphorylation and IFN-γ secretion could be improved through addition of IL-2 to HPV-specific T cell lines from RRP patients. Therapeutic vaccination or interventions aimed at restoring Th1-like cytokine responses to HPV proteins and reversing anergy could improve clinical outcomes for RRP patients.

Responsible conduct of research: Preparedness for times of crisis.

A live, virtual conference, "Driving Responsible Conduct of Research during a Pandemic," was held in April 2021, 13 months after the COVID-19 pandemic fundamentally altered the conduct of clinical research across the USA. New York was an early epicenter of the US pandemic, highlighting preexisting problems in clinical research and allowing us to assess lessons learned and to identify best practices for the future. Risks and opportunities were categorized broadly into three areas, protecting the welfare and safety of human subjects, ensuring trust in science and medicine, and implementing efficient, ethical, and compliant clinical research. Analysis of conference proceedings, and recent publications, shows a need for preparedness that is more effective, robust partnerships, and organizational systems and standards to strengthen the ethical and responsible conduct of research.

T(H)2-like chemokine patterns correlate with disease severity in patients with recurrent respiratory papillomatosis.

Recurrent respiratory papillomatosis (RRP), characterized by the recurrent growth of benign tumors of the respiratory tract, is caused by infection with human papillomavirus (HPV), predominantly types 6 and 11. Surgical removal of these lesions can be required as frequently as every 3 to 4 wks to maintain a patent airway. There is no approved medical treatment for this disease. In this study, we have characterized the T(H)2-like chemokine profile (CCL17, CCL18, CCL20, CCL22) in patients with RRP and asked whether it was modulated in patients who had achieved significant clinical improvement. CCL17, CCL18 and CCL22 messenger RNAs (mRNAs) were increased in papillomas compared with clinically normal laryngeal epithelium of the RRP patients. Overall, CCL20 mRNA expression was not increased, but there was intense, selective CCL20 protein expression in the basal layer of the papillomas. Patients with RRP expressed more CCL17 (p = 0.003), CCL18 (p = 0.0003), and CCL22 (p = 0.007) in their plasma than controls. Plasma CCL18 decreased over time in three patients enrolled in a pilot clinical trial of celecoxib, and the decrease occurred in conjunction with clinical improvement. There was a significant correlation between sustained clinical remission in additional patients with RRP and reduced levels of CCL17 (p = 0.01), CCL22 (p = 0.002) and CCL18 (p = 0.05). Thus, the change in expression of these three plasma T(H)2-like chemokines may, with future studies, prove to serve as a useful biomarker for predicting disease prognosis.

Constitutive overexpression of the oncogene Rac1 in the airway of recurrent respiratory papillomatosis patients is a targetable host-susceptibility factor.

Recurrent respiratory papillomatosis (RRP) is caused by human papillomaviruses (HPVs), primarily types 6 and 11. The disease is characterized by multiple recurrences of airway papillomas, resulting in high levels of morbidity and significant mortality. The prevalence of latent HPV in the larynx of the general population is much greater than the prevalence of RRP, suggesting a host-susceptibility factor for disease. We report that the oncogene Rac1 and its downstream product cyclooxygenase-2 (COX-2) are both constitutively expressed at high levels throughout the airway of these patients, independent of active HPV infection. Use of the COX-2 inhibitor celecoxib in primary papilloma cell culture resulted in the downregulation of HPV transcription. Furthermore, a proof-of-principle study treating three patients with severe RRP with celecoxib resulted in remission of disease in all cases. Therefore, we have identified the first pharmacologically targetable host-susceptibility pathway that contributes to RRP recurrence.

Toll-like receptor agonists, poly(I:C) and flagellin, lead to IL-36γ induction with divergent release kinetics and differentially alter autophagy in primary human keratinocytes

IL-36γ, a pro-inflammatory member of the IL-1 cytokine superfamily, can be induced and secreted by normal human foreskin keratinocytes (HFKs) in response to pathogenic stimuli, however, the mechanisms underlying the secretion are unknown. In this study, we demonstrate that stimulation with the TLR3 agonist, poly (I:C), led to a delayed secretion of IL-36γ compared to stimulation with the TLR5 agonist, flagellin, despite equal levels of the cytokine (p = 0.006). IL-36γ was shown to be released from HFKs in its inactive, uncleaved form, based on western blotting. Moreover, recombinant IL-36γ in its activated, cleaved form induced endogenous IL-36γ 10-fold (p = 0.004) and CXCL8 five-fold (p = 0.003) over baseline levels compared to unactivated full-length recombinant IL-36γ. The ratio of LC3b-II/LC3b-I was significantly higher in poly(I:C)-treated cells compared to flagellin-treated and unstimulated controls without a change in SQSTM1/p62 after 24 hours of stimulation (p = 0.043). Under fluorescence microscopy, poly(I:C) led to a two-fold increase at eight hours and four-fold increase at 24 hours in accumulated autophagosomes post-stimulation (p = 0.032). In contrast, autophagosomes were unchanged relative to baseline in response to flagellin. Bafilomycin A1 treatment enhanced poly(I:C)-mediated IL-36γ secretion (p = 0.044) while rapamycin led to a noticeable, but non-significant, increase in flagellin-mediated IL-36γ secretion, indicating that interrupting autophagic flux can alter IL-3γ grelease from HFKs. Finally, we show that, compared to clinically normal laryngeal tissue, there were significantly higher levels of LC3b-II in HPV-infected respiratory papilloma tissue, indicating a higher number of autophagosomes; a signature of disrupted autophagic flux.

Oropharyngeal tumor cells induce COX-2 expression in peripheral blood monocytes by secretion of IL-1α.

Oropharyngeal squamous cell cancer (OPC) accounts for 3% of all cancers and greater than 1.5% of all cancer deaths in the United States, with marked treatment-associated morbidity in survivors. More than 80% of OPC is caused by HPV16. Tumors induced by HPV have been linked to impaired immune functions, with most studies focused on the local tumor microenvironment. Fewer studies have characterized the effects of these tumors on systemic responses in OPC, especially innate responses that drive subsequent adaptive responses, potentially creating feed-back loops favorable to the tumor. Here we report that elevated plasma levels of PGE2 are expressed in half of patients with OPC secondary to overexpression of COX-2 by peripheral blood monocytes, and this expression is driven by IL-1α secreted by the tumors. Monocytes from patients are much more sensitive to the stimulation than monocytes from controls, suggesting the possibility of enhanced immune-modulating feed-back loops. Furthermore, control monocytes pre-exposed to PGE2 overexpress COX-2 in response to IL-1α, simulating responses made by monocytes from some OPC patients. Disrupting the PGE2/IL-1α feed-back loop can have potential impact on targeted medical therapies.

Extracellular vesicles produced by primary human keratinocytes in response to TLR agonists induce stimulus-specific responses in antigen-presenting cells.

Cells can communicate through the extracellular vesicles (EVs) they secrete. Pathogen associated molecular patterns (PAMPs), alter the biophysical and communicative properties of EVs released from cells, but the functional consequences of these changes are unknown. Characterization of keratinocyte-derived EVs after poly(I:C) treatment (poly(I:C)-EVs) showed slight differences in levels of EV markers TSG101 and Alix, a loss of CD63 and were positive for autophagosome marker LC3b-II and the cytokine IL36γ compared to EVs from unstimulated keratinocytes (control-EVs). Flagellin treatment (flagellin-EVs) led to an EV marker profile like control-EVs but lacked LC3b-II. Flagellin-EVs also lacked IL-36γ despite nearly identical intracellular levels. While poly(I:C) treatment led to the clear emergence of a > 200 nm diameter EV sub-population, these were not found in flagellin-EVs. EV associated IL-36γ colocalized with LC3b-II in density gradient analysis, equilibrating to 1.10 g/mL, indicating a common EV species. Poly(I:C), but not flagellin, induced intracellular vesicles positive for IL-36γ, LC3b-II, Alix and TSG101, consistent with fusion of autophagosomes and multivesicular bodies. Simultaneous rapamycin and flagellin treatment induced similar intracellular vesicles but was insufficient for the release of IL-36γ+/LC3b-II+ EVs. Finally, a qRT-PCR array screen showed eight cytokine/chemokine transcripts were altered (p < 0.05) in monocyte-derived Langerhans cells (LCs) when stimulated with poly(I:C)-EVs while three were altered when LCs were stimulated with flagellin-EVs compared to control-EVs. After independent confirmation, poly(I:C)-EVs upregulated BMP6 (p = 0.035) and flagellin-EVs upregulated CXCL8 (p = 0.005), VEGFA (p = 0.018) and PTGS2 (p = 0.020) compared to control-EVs. We conclude that exogenous signals derived from pathogens can alter keratinocyte-mediated modulation of the local immune responses by inducing changes in the types of EVs secreted and responses in antigen presenting cells.

Pak1 and Pak2 are activated in recurrent respiratory papillomas, contributing to one pathway of Rac1-mediated COX-2 expression.

Recurrent respiratory papillomas are premalignant tumors of the airway caused by human papillomaviruses (HPVs), primarily Types 6 and 11. We had reported that respiratory papillomas overexpress the epidermal growth factor receptor (EGFR), the small GTPase Rac1 and cyclooxygenase-2 (COX-2), and have enhanced nuclear factor-kappaB (NFkappaB) activation with decreased levels of IkappaB-beta but not IkappaB-alpha. We also showed that EGFR-activated Rac1 mediates expression of COX-2 through activation of p38 mitogen-activated protein kinase. We have now asked whether the p21-activated kinases Pak1 or Pak2 mediate activation of p38 by Rac1 in papilloma cells. Pak1 and Pak2 were constitutively activated in vivo in papilloma tissue compared with normal epithelium, and Rac1 siRNA reduced the level of both phospho-Pak1 and phospho-Pak2 in cultured papilloma cells. Reduction in Pak1 and Pak2 with siRNA decreased the COX-2 expression in papilloma cells, increased the levels of IkappaB-beta and reduced the nuclear localization of NF-kappaB, but had no effect on p38 phosphorylation. Our studies suggest that Rac1 --> Pak1/Pak2 --> NFkappaB is a separate pathway that contributes to the expression of COX-2 in HPV-induced papillomas, independently of the previously described Rac1 --> p38 --> COX-2 pathway.

Genetic variants in TAP are associated with high-grade cervical neoplasia.

PURPOSE: The transporter associated with antigen processing (TAP) is essential in assembling MHC-I proteins. Human papillomavirus (HPV) evades immune recognition by decreasing class I MHC cell surface expression through down-regulation of TAP1 levels. Consistent with heterogeneity in MHC expression is the individual variability in clearing detectable HPV infections. Genetic polymorphisms in TAP genes may affect protein structure, function, and the ability to clear HPV infection. EXPERIMENTAL DESIGN: Case-control study of women with cervical intraepithelial neoplasia (CIN) II or III (n = 114) and women without high-grade CIN (n = 366). Five nonsynonymous single nucleotide polymorphisms (SNP) in TAP1 and TAP2 were genotyped using DNA collected in cervicovaginal lavage samples using microsphere array technology (Luminex xMAP). HPV typing was done using a PCR-based system with MY09/MY11 primers. TAP1 and TAP2 SNPs were validated by direct sequencing. RESULTS: Differences in allele distribution between women with high-grade cervical neoplasia and women without was seen for TAP1 I333V (P = 0.02) and TAP1 D637G (P = 0.01). The odds ratios (OR) for CIN III were significantly lower among carriers of the TAP1 I333V polymorphism (OR, 0.28; 95% confidence interval, 0.1-0.8), and TAP1 D637G polymorphism (OR, 0.27; 95% confidence interval, 0.1-0.7). These associations remained significant even after restricting the evaluation to women who were positive for high-risk HPV types. CONCLUSIONS: In addition to the down-regulation of MHC-1 by oncogenic HPV, HPV pathogenesis might be facilitated by polymorphisms in the TAP proteins. Identifying TAP polymorphisms may potentially be used to identify women less susceptible to progression to high-grade CIN and cervical cancer.

Gefitinib Inhibits Invasion and Metastasis of Osteosarcoma via Inhibition of Macrophage Receptor Interacting Serine-Threonine Kinase 2.

Most patients with osteosarcoma have subclinical pulmonary micrometastases at diagnosis. Mounting evidence suggests that macrophages facilitate metastasis. As the EGFR has been implicated in carcinoma-macrophage cross-talk, in this study, we asked whether gefitinib, an EGFR inhibitor, reduces osteosarcoma invasion and metastatic outgrowth using the K7M2-Balb/c syngeneic murine model. Macrophages enhanced osteosarcoma invasion in vitro, which was suppressed by gefitinib. Oral gefitinib inhibited tumor extravasation in the lung and reduced the size of metastatic foci, resulting in reduced metastatic burden. Gefitinib also altered pulmonary macrophage phenotype, increasing MHCII and decreasing CD206 expression compared with controls. Surprisingly, these effects are mediated through inhibition of macrophage receptor interacting protein kinase 2 (RIPK2), rather than EGFR. Supporting this, lapatinib, a highly specific EGFR inhibitor that does not inhibit RIPK2, had no effect on macrophage-promoted invasion, and RIPK2-/- macrophages failed to promote invasion. The selective RIPK2 inhibitor WEHI-345 blocked tumor cell invasion in vitro and reduced metastatic burden in vivo In conclusion, our results indicate that gefitinib blocks macrophage-promoted invasion and metastatic extravasation by reprogramming macrophages through inhibition of RIPK2.

Altered Monocyte and Langerhans Cell Innate Immunity in Patients With Recurrent Respiratory Papillomatosis (RRP).

The micromilieu within respiratory papillomas supports persistent human papillomavirus (HPV) infection and disease recurrence in patients with recurrent respiratory papillomatosis (RRP). These patients show polarized (TH2-/Treg) adaptive immunity in papillomas and blood, enriched immature Langerhans cell (iLC) numbers, and overexpression of cyclooxygenase-2/prostaglandin E2 (PGE2) in the upper airway. Blood monocyte-derived, and tissue-derived iLCs from RRP patients and controls were now studied to more fully understand innate immune dysregulation in RRP. Patients' monocytes generated fewer iLCs than controls, due to a reduced fraction of classical monocytes that generated most but not all the iLCs. Prostaglandin E2, which was elevated in RRP plasma, reduced monocyte-iLC differentiation from controls to the levels of RRP patients, but had no effect on subsequent iLC maturation. Cytokine/chemokine responses by iLCs from papillomas, foreskin, and abdominal skin differed significantly. Freshly derived tissue iLCs expressed low CCL-1 and high CCL-20 mRNAs and were unresponsive to IL-36γ stimulation. Papilloma iLCs uniquely expressed IL-36γ at baseline and expressed CCL1 when cultured overnight outside their immunosuppressive microenvironment without additional stimulation. We conclude that monocyte/iLC innate immunity is impaired in RRP, in part due to increased PGE2 exposure in vivo. The immunosuppressive papilloma microenvironment likely alters iLC responses, and vice versa, supporting TH2-like/Treg HPV-specific adaptive immunity in RRP.

Immune dysregulation and tumor-associated gene changes in recurrent respiratory papillomatosis: a paired microarray analysis.

Recurrent respiratory papillomas (RRP) are benign airway tumors, caused primarily by human papillomaviruses (HPV) types 6 and 11. The disease is characterized by multiple recurrences after surgical removal, with limited effective therapy. To identify novel targets for future therapy, we established transcriptional profiles for actively growing papillomas compared with autologous, clinically normal, laryngeal epithelia (adjacent tissue). Total ribonucleic acid (RNA) from 12 papillomas and 12 adjacent tissues were analyzed by microarray, and the matched sets of tissues compared by paired t test, to identify differentially expressed genes in papilloma tissues while minimizing variations intrinsic to individual patients. Quantitative polymerase chain reaction (PCR) was used to confirm the relative expression levels for a subset of genes. Within the 109 differentially expressed transcripts whose expression varied at least three-fold were two large groups of genes with related functions. The first group consisted of 18 genes related to host defense, including both innate and adaptive immunity. The second group contained 37 genes that likely contribute to growth of papillomas as benign tumors, since the altered pattern of expression also had been reported previously in many cancers. Our results support our previous studies that document a systemic T(H)2-like adaptive immune response in RRP, and suggest that there is a role for altered innate immunity in RRP as well. We propose that HPV 6 and 11 infection establishes a tumorigenic microenvironment characterized by alteration of both innate inflammatory signals and adaptive immune responses that prevent effective T(H)1-like response, in conjunction with altered expression of numerous genes that regulate cellular growth and differentiation.

Epidermal growth factor-induced cyclooxygenase-2 expression is mediated through phosphatidylinositol-3 kinase, not mitogen-activated protein/extracellular signal-regulated kinase kinase, in recurrent respiratory papillomas.

PURPOSE: Recurrent respiratory papillomas, caused by human papillomaviruses, are premalignant tumors that overexpress the epidermal growth factor receptor (EGFR). The goals of this study were as follows: (a) to evaluate the expression of cyclooxygenase-2 (COX-2) in papillomas, (b) to investigate the role of EGFR signaling in COX-2 expression, and (c) to determine whether COX-2 activity is important for the growth of papilloma cells. EXPERIMENTAL DESIGN: Immunohistochemistry, Western blotting, and real-time PCR were used to determine levels of COX-2 in papilloma and normal laryngeal tissue. Explant cultures of both normal laryngeal and papilloma cells were used to define the signaling pathways that regulate COX-2 expression and investigate the potential of targeting COX-2 as a strategy to suppress papilloma growth. RESULTS: COX-2 levels were markedly increased in papillomas. In vitro studies suggested that overexpression in papillomas reflected activation of EGFR-->phosphatidylinositol 3-kinase signaling. Treatment with prostaglandin E2 (PGE2) induced COX-2, whereas celecoxib, a selective COX-2 inhibitor, suppressed levels of COX-2, suggesting a positive feedback loop. Moreover, treatment with PGE2 stimulated papilloma cell growth, whereas celecoxib suppressed proliferation and induced apoptosis. CONCLUSIONS: Overexpression of COX-2 in papillomas seems to be a consequence of enhanced EGFR-->phosphatidylinositol 3-kinase signaling. We propose a positive feedback loop for COX-2 expression, with induction of COX-2 resulting in enhanced PGE2 synthesis and further expression of COX-2 that contributes to the growth of papillomas in vivo. These data strengthen the rationale for evaluating whether nonsteroidal anti-inflammatory drugs, prototypic COX inhibitors, will be useful in the management of respiratory papillomas.

Four mutations in Epidermodysplasia verruciformis 1 (EVER1) gene are not contributors to susceptibility in RRP.

OBJECTIVE: Epidermodysplasia verruciformis is a skin disease characterized by abnormal susceptibility to human papilloma viruses. Recently four mutations in the Epidermodysplasia verruciformis 1 gene (EVER1, also known as TMC6) have been associated with the disease. Because of the phenotypic similarity between Epidermodysplasia verruciformis and recurrent respiratory papillomatosis, we decided to investigate whether any of these mutations accounts for the susceptibility to human papilloma viruses in subjects with recurrent respiratory papillomatosis (RRP). METHODS: Allele-specific PCR and restriction fragment length polymorphisms (RFLPs) were employed for genotyping a cohort of 101 patients with recurrent respiratory papillomatosis. RESULTS: None of these four mutations were found in the studied subjects. CONCLUSION: The absence of these mutations in RRP patients might indicate that EVER 1 alleles are not associated with susceptibility to RRP, or that other, as yet unidentified, mutations in the Epidermodysplasia verruciformis 1 gene, might account for the susceptibility to RRP.

Clinical trial of photodynamic therapy with meso-tetra (hydroxyphenyl) chlorin for respiratory papillomatosis.

OBJECTIVE: To determine the efficacy of photodynamic therapy (PDT) with meso-tetra (hydroxyphenyl) chlorin (m-THPC) photosensitizer for recurrent respiratory papillomatosis. DESIGN: Parallel-arm, randomized trial of patients requiring surgery at least 3 times yearly with single PDT 6 or 18 months after enrollment and 12-month follow-up. Disease extent was scored and papillomas were removed during direct endoscopy every 3 months after enrollment. SETTING: Tertiary medical centers. PATIENTS: Of 23 patients aged 4 to 60 years enrolled in the study, 15 patients, plus 2 in the late group without PDT owing to airway risk, completed the study. Six patients withdrew voluntarily after PDT. INTERVENTION: Intravenous administration of m-THPC 6 days before direct endoscopic PDT with 80 to 100 J of light for adults and 60 to 80 J for children. MAIN OUTCOME MEASURES: Difference in severity scores between the early and late groups and between pre- and post-PDT scores for all patients. Secondary measures were the associations between baseline characteristics and response and changes in immune response and the prevalence of latent viral DNA. RESULTS: There were significant differences between groups, with marked improvement in laryngeal disease across time after PDT (P = .006). Five of 15 patients were in remission 12 to 15 months after treatment, but there was recurrence of disease after 3 to 5 years. Tracheal disease was not responsive to PDT. No change occurred in the prevalence of latent human papillomavirus DNA. The immune response to virus improved with clinical response. CONCLUSIONS: Use of m-THPC PDT reduces the severity of laryngeal papillomas, possibly through an improved immune response. Failure to maintain remission with time suggests that this is not an optimal treatment.