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.

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.

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.

Abstract PR13: Surgical excision of the primary tumor in osteosarcoma model results in enhanced metastatic growth by modulating the lung immune microenvironment

Surgery has been shown to enhance metastasis in a number of cancers. To examine this in the context of osteosarcoma, we implanted syngeneic murine K7M2 cells into the tibia of BALB/c mice, which we had shown previously to result in immediate seeding of K7M2 cells into the lung. One week post-implantation, mice were assigned to either control or surgical groups and all mice were euthanized at week 4 post-implantation. Mice that underwent amputation of the primary tumor displayed an increase in the number of pulmonary surface nodules as compared to tumor-bearing control animals (17 vs. 9.5; p&lt;0.05), showing that excision of the primary tumor indeed enhances metastasis in this model. As we previously showed that K7M2 metastasis without surgical intervention is strongly inhibited by re-educating tumor-associated macrophages (TAMs) with gefitinib, we also examined the effect of gefitinib on surgery-accelerated metastasis. We found that perioperative gefitinib abrogated the effects of primary tumor removal on the development of pulmonary metastases (17 vs. 6; p&lt; 0.01), strongly suggesting that TAMs also mediate surgery-accelerated metastasis. To examine changes in the pulmonary immune milieu, we utilized the same model of surgery-accelerated metastasis. Lungs were homogenized and immune cell populations were analyzed using flow cytometric analysis at 48 hours and 3 weeks after surgery. We found that surgery caused a significant reduction in antitumor macrophages, identified by MHCII positivity (21.1% vs. 13.2%; p&lt;0.01), and a significant increase in protumor macrophages, identified by CD206 positivity (33.0% vs. 42.4%; p&lt;0.01), at 48 hours after surgical resection. There was no change in the proportion of CD4+ or CD8+ T cells at this time point. At 3 weeks post-surgery the proportion of macrophage populations became similar for both groups, but there was now a small but significant reduction in the CD4+ and CD8+ T cells in the surgical group (68.4% vs. 60.3%; p&lt;0.05 and 25.0% vs. 19.3%; p&lt;0.01). In conclusion, surgical removal of the primary tumor accelerated the growth of pulmonary metastases in a murine model of OS. Gefitinib was able to abrogate this effect, suggesting macrophages as key cellular mediators. Furthermore, surgery altered the macrophage phenotype within the lungs in the acute postoperative period toward a protumor state, subsequently reducing the CD4+ or CD8+ T-cell populations. Taken together these data suggest that surgery contributes to enhanced metastatic outgrowth by altering the immune microenvironment to an immunosuppressive and protumor state.

This abstract is also being presented as Poster B38.

Citation Format: Michelle P. Kallis, Caroline Maloney, Morris Edelman, Samuel Z. Soffer, Marc Symons, Bettie M. Steinberg. Surgical excision of the primary tumor in osteosarcoma model results in enhanced metastatic growth by modulating the lung immune microenvironment [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr PR13.

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.

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.

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 (T_H2-/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 T_H2-like/Treg HPV-specific adaptive immunity in RRP.

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.

The Macrophage Inhibitor CNI-1493 Blocks Metastasis in a Mouse Model of Ewing Sarcoma through Inhibition of Extravasation

Metastatic Ewing Sarcoma carries a poor prognosis, and novel therapeutics to prevent and treat metastatic disease are greatly needed. Recent evidence demonstrates that tumor-associated macrophages in Ewing Sarcoma are associated with more advanced disease. While some macrophage phenotypes (M1) exhibit anti-tumor activity, distinct phenotypes (M2) may contribute to malignant progression and metastasis. In this study, we show that M2 macrophages promote Ewing Sarcoma invasion and extravasation, pointing to a potential target of anti-metastatic therapy. CNI-1493 is a selective inhibitor of macrophage function and has shown to be safe in clinical trials as an anti-inflammatory agent. In a xenograft mouse model of metastatic Ewing Sarcoma, CNI-1493 treatment dramatically reduces metastatic tumor burden. Furthermore, metastases in treated animals have a less invasive morphology. We show in vitro that CNI-1493 decreases M2-stimulated Ewing Sarcoma tumor cell invasion and extravasation, offering a functional mechanism through which CNI-1493 attenuates metastasis. These data indicate that CNI-1493 may be a safe and effective adjuvant agent for the prevention and treatment of metastatic Ewing Sarcoma.

Human papillomavirus and diseases of the upper airway: head and neck cancer and respiratory papillomatosis

Human papillomavirus (HPV) infection is causally associated with benign and malignant diseases of the upper airway, including respiratory papillomatosis and oropharyngeal cancer. Low-risk HPV types 6 and 11 are the predominant cause of papillomatosis, whereas only HPV16 definitively satisfies both molecular and epidemiological causal criteria as a carcinogenic or high-risk type in the upper airway. HPV16 E6/E7 mRNA expression and integration are observed predominantly among oropharyngeal cancers, and experimental models have shown E6/E7 expression to be necessary for the initiation and maintenance of the malignant phenotype of these cancers. From an epidemiological perspective, a strong and consistent association between markers of HPV16 exposure and oropharyngeal cancer has been demonstrated in numerous case-control studies. HPV-positive oropharyngeal cancers have also been shown to be distinct from HPV-negative head and neck squamous cell cancers with regard to risk-factor profiles, molecular genetic alterations, population-level incidence trends over time, and prognosis. Tumor HPV status (as determined by certain HPV16 in situ hybridization assays or certain p16 immunohistochemistry assays) is the strongest determinant of survival for patients with local-regionally advanced oropharyngeal cancer: patients with HPV-positive cancer have at least a 50% improvement in overall survival at 5 years, which is equivalent to an approximate 30% difference in absolute survival. Thus, HPV status determination is now part of the routine diagnostic evaluation for prognostication. Preliminary evidence indicates that a small proportion of head and neck cancers may be caused by additional HPV types (e.g., 18, 31, 33, 35) and that HPV-caused cancers may rarely arise from non-oropharyngeal sites (e.g., the oral cavity, nasopharynx, and larynx). Whether or not HPV vaccination has the potential to prevent oral HPV infections that lead to cancer or papillomatosis in the upper airway is currently unknown, as is the potential for secondary prevention with HPV detection. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

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.

Celecoxib inhibits invasion and metastasis via a cyclooxygenase 2-independent mechanism in an in vitro model of Ewing sarcoma

BACKGROUND/INTRODUCTION

Previously, we reported that celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, prevented lung metastases but did not affect tumor growth in a model of Ewing sarcoma. Cyclooxygenase-2 inhibition has been proposed as an antimetastatic strategy. The mechanism of action remains unclear.

METHODS

Ewing sarcoma cells were suspended in a soluble basement membrane extract (Cultrex; Trevigen, Inc, Gaithersburg, MD) and supplemented with celecoxib or with rofecoxib, a second COX-2 inhibitor, above a filter. Controls received solvent. After 48 hours, the cells that invaded through the basement membrane and filter were stained and counted. The assay was repeated with the addition of 500-nM prostaglandin E2 (PGE(2)).

RESULTS

Invasion was significantly decreased in the celecoxib groups compared with the control. The addition of PGE(2) did not overcome celecoxib inhibition. Rofecoxib did not significantly affect invasion compared with control either with or without PGE(2).

CONCLUSIONS

Celecoxib significantly inhibits invasion of Ewing sarcoma cells in vitro. Prostaglandin E2, a downstream product of COX-2, did not reverse in vitro inhibition, suggesting that celecoxib acts through a COX-2-independent mechanism. This is further supported by the failure of rofecoxib to inhibit invasion despite more selectively inhibiting COX-2.

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.

Immune suppression in premalignant respiratory papillomas: enriched functional CD4+Foxp3+ regulatory T cells and PD-1/PD-L1/L2 expression

PURPOSE

Respiratory papillomas, caused by human papillomaviruses types 6 and 11 (HPV6/11), are premalignant lesions with potential for malignant conversion. The cytokine and chemokine micromilieu of papillomas is T(H)2-like with a marked absence of IFN-γ expression. To illuminate why patients with recurrent respiratory papillomatosis (RRP) fail to effectively control their disease, we further investigated the suppressive cellular microenvironment in papillomas.

EXPERIMENTAL DESIGN

CD4(+)CD25(+)CD127(low/-)Foxp3(+) regulatory T cells (Treg) and CD4(+)CD25(-)CD127(low/-)Foxp3(-) T cells within papillomas were characterized and isolated. Their suppressor function was measured by inhibition of peripheral blood mononuclear cell (PBMC) proliferation. Expression of PD-1, CD69, and Helios was identified on these T cells. PD-L1, PD-L2, CCL17, and CCL22 mRNA was also identified in papillomas by quantitative PCR.

RESULTS

Functional Tregs were markedly enriched in papillomas and strongly inhibited anti-CD3 and anti-CD28 antibody activated PBMC proliferation. The natural Treg marker Helios was reduced on Tregs from papillomas, indicating that the majority of Tregs in papillomas are adaptive. The majority of the papilloma-derived CD4(+) T cells expressed the CD4(+)CD25(-)CD127(low/-)Foxp3(-)PD1(+)CD69(+) phenotype and failed to suppress PBMC proliferation, suggesting that they are chronically activated and exhausted. The Treg-attracting chemokine CCL22 was equally expressed by all laryngeal tissues examined. However, CCL17 was robustly expressed by papillomas compared with unaffected laryngeal tissues from RRP patients and individuals without RRP. PD-L1 was elevated in papillomas compared with control laryngeal tissues.

CONCLUSIONS

Papilloma CD4(+) T cells are enriched with functional Tregs, and the adaptive Helios(-) Treg fraction was increased within the T(H)2-like papilloma micromilieu. CD4(+)CD25(-)CD127(low/-)Foxp3(-) T-cells failed to suppress PBMC proliferation and may be exhausted. The PD-1/PDL-1 pathway may represent an additional immunosuppressive mechanism that contributes to defective HPV6/11 clearance in RRP.

Opportunities and challenges facing biomarker development for personalized head and neck cancer treatment

Head and neck oncologists have traditionally relied on clinical tumor features and patient characteristics to guide care of individual patients. As surgical, radiotherapeutic, and systemic treatments have evolved to become more anatomically precise and mechanistically specific, the opportunity for improved cure and functional patient recovery has never been more promising for this historically debilitating cancer. However, personalized treatment must be accompanied by sophisticated patient selection to triage the application of advanced therapies toward ideal patient candidates. In this monograph, we review current progress, investigative themes, and key challenges facing head and neck cancer biomarker development intended to make personalized head and neck cancer treatment a clinical reality.

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.

Selective inhibition of cyclooxygenase-2 suppresses metastatic disease without affecting primary tumor growth in a murine model of Ewing sarcoma

BACKGROUND/PURPOSE

Mammalian target of rapamycin suppression by rapamycin inhibits tumor growth and neovascularization via cyclooxygenase-2 (COX-2) downregulation with no effect on lung metastases. We hypothesize that combining a selective COX-2 antagonist (celecoxib) with rapamycin would decrease lung metastases.

METHODS

Ewing sarcoma cells (SK-NEP-1) were surgically implanted into the left kidney of athymic mice (n = 40). The mice were divided into 4 treatment groups (control, rapamycin only, celecoxib only, and combination) and then killed at 6 weeks. Primary tumors were weighed. Vasculature was examined using lectin angiography and immunohistochemistry, and lung metastases were examined using H&E and CD99 immunostaining. Tumor weight and lung metastases were analyzed.

RESULTS

Mean primary tumor weights were significantly reduced in the rapamycin-treated groups but not in the celecoxib-only group. Lectin angiography and endothelial markers immunostaining showed markedly decreased vascularity in the rapamycin-treated groups but not in the celecoxib-only group. Celecoxib-treated groups showed significantly fewer mice with lung metastases than non-celecoxib-treated groups.

CONCLUSION

Celecoxib prevents lung metastasis in a murine model of Ewing sarcoma with no effect on tumor size or neovascularization. Cyclooxygenase-2 may represent a future potential target for metastatic disease prevention.

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.

Recurrent respiratory papillomatosis: a complex defect in immune responsiveness to human papillomavirus-6 and -11

Recurrent respiratory papillomatosis (RRP) is a rare disease of the larynx caused by infection with human papillomaviruses (HPV) -6 or -11, associated with significant morbidity and on occasion mortality. Here we summarize our current understanding of the permissive adaptive and innate responses made by patients with RRP that support chronic HPV infection and prevent immune clearance of these viruses. Furthermore, we provide new evidence of T(H)2-like polarization in papillomas and blood of patients with RRP, restricted CD4 and CD8 Vbeta repertoires, the effect of HPV-11 early protein E6 on T-cell alloreactivity, enriched Langerhans cell presence in papillomas, and evidence that natural killer cells are dysfunctional in RRP. We review the immunogenetic mechanisms that regulate the dysfunctional responses made by patients with RRP in response to HPV infection of the upper airway. In addition, we are identifying T-cell epitopes on HPV-11 early proteins, in the context of human leukocyte antigen (HLA) class II alleles enriched in RRP that should help generate a therapeutic vaccine. Taken together, RRP is a complex, multigene disease manifesting as a tissue and HPV-specific, immune deficiency that prevents effective clearance and/or control of HPV-6 and -11 infection.

Abstract 5062: Rac1 signaling is up-regulated in normal tissue adjacent to recurrent respiratory papillomas

Recurrent respiratory papillomas, caused by human papillomavirus infection, are benign tumors that block the airway and have significant potential for malignant conversion. Previously we have shown that the epidermal growth factor receptor (EGFR) is overexpressed in papillomas. This overexpression leads to the activation of a novel signaling pathway involving increased expression of the Rho-family member GTPase Rac1, activation of the p38 mitogen activated kinase and increased expression of cyclooxygenase 2 (COX-2). This pathway is not activated in normal laryngeal epithelial tissue samples from individuals without the disease, but is constitutively active in papilloma tissue. Here we have investigated the extent to which the EGFR → Rac1 → p38 → COX-2 pathway is activated in clinically normal airway tissue from patients with respiratory papillomas. Surprisingly, we found that the Rac1 and COX-2 levels are comparable in “normal” and papilloma tissues, suggesting widespread activation of this pathway in the laryngeal mucosa, without marked elevation of the EGFR in the “normal” adjacent tissue. Moreover, preliminary data suggests that overexpression of Rac1 in these patients may be systemic, as it is also found at higher levels in peripheral blood mononuclear cells. We hypothesize that Rac1 overexpression may be a rare genetic trait that predisposes these patients to develop recurrent respiratory papillomatosis. Furthermore, investigation into Rac1 levels revealed the presence of a splice variant known as Rac1b. This constitutively active form of Rac1 is found at higher levels in papilloma tissue when compared to “normal” adjacent tissue from the same patient, possibly contributing to the growth of the tumors. Our current research is focused on determining the mechanism of Rac1 overexpression and elucidating the role of the Rac1 isoforms in papilloma cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5062.

Activating killer cell immunoglobulin-like receptors 3DS1 and 2DS1 protect against developing the severe form of recurrent respiratory papillomatosis

The polymorphic killer cell immunoglobulin-like receptors (KIR) control natural killer (NK) cell response against viral infection and tumor transformation. Here we investigated if select KIR genes are associated with recurrent respiratory papillomatosis (RRP), a rare disease of the larynx and upper airway caused by human papillomaviruses (HPV)-6/11. DNA from 66 RRP patients and 195 healthy controls were characterized for KIR and HLA gene polymorphism. Patients lacking activating KIR genes 3DS1 and 2DS1 were more common in severe RRP compared with mild-moderate RRP (78.8% vs 48.5%, p = 0.019). Further, patients carrying any of the known susceptible HLA-DRB1/DQB1 alleles were more frequently negative for KIR3DS1 (p = 0.006), KIR2DS1 (p = 0.003) or KIR2DS5 (p = 0.004) compared with controls carrying any of these HLA allotypes. Nearly 80% of the patients with severe disease were missing the protective HLA-DQB1*0602 allele as well as both KIR3DS1 and KIR2DS1 genes. Phenotyping of papilloma-infiltrating mononuclear-cells revealed an elevated numbers of NK cells and CD57(+)CD4(+) T cells in KIR3DS1(-)KIR2DS1(-) patients compared with patients carrying either one or both of these KIRs. Our data suggest that NK cells expressing activating receptors KIR3DS1 and KIR2DS1 may be necessary to trigger an effective early immune response against HPV-infected targets to establish resistance to RRP development.

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.

Cyclooxygenase 2 mediates the antiangiogenic effect of rapamycin in Ewing sarcoma

BACKGROUND

Rapamycin can inhibit tumor growth and angiogenesis in various human cancers. Cyclooxygenase 2 (COX-2) is involved in the angiogenic process. We hypothesized that the antiangiogenic effect of rapamycin may be mediated by suppression of COX-2.

METHODS

Ewing sarcoma (ES) cells were implanted in athymic mice. Selected animals were treated with rapamycin for 5 weeks. Tumor vascularity was assessed by lectin perfusion angiography and immunohistochemistry. Phosphorylation of mammalian target of rapamycin pathway proteins was determined by Western blot analysis. Staining of COX-2 protein was determined by immunohistochemistry, and expression of COX-2 messenger RNA levels was assessed with quantitative real-time (RT) polymerase chain reaction.

RESULTS

Mean tumor weights were significantly reduced in the treated group (5.43 g +/- 1.43 SEM vs 0.49 g +/- 0.15 SEM, P < .003). There was abundant vasculature in the control group and blunted vascularity in the treated xenografts. The phosphorylation of p70s6k and Akt was not inhibited in the rapamycin-treated tumors. Cyclooxygenase 2 was suppressed in the treated xenografts at both the protein and messenger RNA levels.

CONCLUSION

Low-dose rapamycin inhibits tumor growth and angiogenesis in human ES without inhibiting the phosphorylation of p70s6k and Akt. Cyclooxygenase 2 levels are inhibited by low-dose treatment of ES with rapamycin. Cyclooxygenase 2 suppression may mediate the antiangiogenic effect of rapamycin in Ewing sarcoma.

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.

Laryngeal papillomatosis is associated with a defect in cellular differentiation

The effects of human papillomavirus infection, which can cause laryngeal papillomas, were studied in vitro in laryngeal stratified squamous epithelial cells. Interferon exposure had only minor effects on the outgrowth of primary cells from tissue fragments and the incorporation of tritiated amino acids by first-passage cells. There was a marked decrease in tritiated thymidine incorporation by papilloma cells when cultured in the presence of interferon, but no effect on thymidine incorporation by normal cells. Differentiation of laryngeal papillomas appears to be abnormal. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of keratins showed that the keratins of high relative molecular mass (Mr 51,000 and 59,000) associated with normal laryngeal differentiation were absent from papilloma tissue. Rather, both papilloma tissue and cultured papilloma cells contained a keratin of Mr 53,000 not normally present. Binding of the fluoresceinated lectin peanut agglutinin to cell surfaces suggested that there were alterations in the normal distribution of glycoproteins or glycolipids on papilloma tissues. Filaggrin, a protein synthesized by differentiating cells, was not detectable in most superficial papilloma cells after immunohistochemical staining. These studies strongly suggest that papilloma cells do not differentiate normally. We propose that this defect may be responsible for the hypertrophy of the tissue.

Up-regulation of Rac1 by epidermal growth factor mediates COX-2 expression in recurrent respiratory papillomas

Recurrent respiratory papillomas are epithelial tumors of the airway caused by human papillomaviruses. We previously reported that the epidermal growth factor receptor (EGFR) is overexpressed in papilloma cells, that cyclooxygenase-2 (COX-2) is induced, and that COX-2 expression in primary papilloma cells requires activation of the EGFR but not Erk. Rac1, a member of the Rho family of GTPases, is a key signaling element that is known to control multiple pathways downstream of the EGFR. Here we report that Rac1 is overexpressed in papilloma cells compared with normal laryngeal epithelial cells and that the increased levels of Rac1 are mediated by EGFR activation. Transfecting cells with Rac1-specific siRNA suppressed COX-2 expression. Surprisingly, Rac1 mediated phosphorylation of p38 mitogen-activated kinase in papilloma cells but not normal cells, and inhibition of p38 with the specific inhibitor SB202190 suppressed COX-2 expression in papilloma cells but had no effect on low-level COX-2 expression in normal cells. Thus, the signaling cascades that regulate COX-2 expression are different in HPV-infected papilloma cells, with a significant contribution by the EGFR-- Rac1-->p38 pathway.

Up-regulation of Rac1 by epidermal growth factor mediates COX-2 expression in recurrent respiratory papillomas

Recurrent respiratory papillomas are epithelial tumors of the airway caused by human papillomaviruses. We previously reported that the epidermal growth factor receptor (EGFR) is overexpressed in papilloma cells, that cyclooxygenase-2 (COX-2) is induced, and that COX-2 expression in primary papilloma cells requires activation of the EGFR but not Erk. Rac1, a member of the Rho family of GTPases, is a key signaling element that is known to control multiple pathways downstream of the EGFR. Here we report that Rac1 is overexpressed in papilloma cells compared with normal laryngeal epithelial cells and that the increased levels of Rac1 are mediated by EGFR activation. Transfecting cells with Rac1-specific siRNA suppressed COX-2 expression. Surprisingly, Rac1 mediated phosphorylation of p38 mitogen-activated kinase in papilloma cells but not normal cells, and inhibition of p38 with the specific inhibitor SB202190 suppressed COX-2 expression in papilloma cells but had no effect on low-level COX-2 expression in normal cells. Thus, the signaling cascades that regulate COX-2 expression are different in HPV-infected papilloma cells, with a significant contribution by the EGFR-- Rac1-->p38 pathway.

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.

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.

Phosphatidylinositol 3-kinase regulates early differentiation in human laryngeal keratinocytes

Epidermal growth factor receptor (EGFR) signaling regulates a variety of cellular functions, including proliferation, gene expression, and differentiation. Infection of laryngeal epithelial cells by human papillomaviruses causes recurrent respiratory papillomas, benign tumors characterized by an altered pattern of differentiation. Papilloma cells overexpress the EGFR and have constitutively active extracellular signal-regulated kinase (ERK) and enhanced phosphatidylinositol 3-kinase (PI3K) activity, but overexpression of the lipid phosphatase PTEN (Phosphatase and Tensin Homolog) reduces activation of Akt by PI3K. We hypothesized that the altered differentiation of papillomas reflects these changes in signaling from the EGFR-ERK and PI3K-Akt pathways and that one or both of these pathways is required for the normal differentiation process in mucosal epithelium. Inhibiting either the enzymatic activity or the synthesis of PI3K in uninfected laryngeal cells blocked expression of keratin-13 (K13), a protein induced during normal differentiation. In contrast, inhibiting activation of ERK had minimal effect. Using ribonucleic acid interference to reduce protein levels of integrin-linked kinase 1 or phosphoinositide-dependent protein kinase 1, intermediates in the activation of Akt by PI3K, or reducing levels of Akt-1 itself did not inhibit K13 expression by normal laryngeal keratinocytes. We conclude that PI3K activation is an important regulator of expression of K13, a marker for the normal differentiation process in human mucosal keratinocytes, that this function does not require activation of Akt-1, and that the failure to express K13 in papilloma cells is not because of reduction in activated Akt.

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.

Failure of gamma interferon but not interleukin-10 expression in response to human papillomavirus type 11 E6 protein in respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is a chronic, debilitating disease of the upper airway caused by human papillomavirus type 6 (HPV-6) or HPV-11. We describe responses of peripheral blood mononuclear cells (PBMC) and T cells from RRP patients and controls to the HPV-11 early proteins E6 and E7. PBMC were exposed in vitro to purified E6 or E7 proteins or transduced with fusion proteins containing the first 11 amino acids of the human immunodeficiency virus type 1 protein tat fused to E6 or E7 (tat-E6/tat-E7). T(H)1-like (interleukin-2 [IL-2], gamma interferon [IFN-gamma], IL-12, and IL-18), and T(H)2-like (IL-4 and IL-10) cytokine mRNAs were identified by reverse transcription-PCR, and IFN-gamma and IL-10 cytokine-producing cells were identified by enzyme-linked immunospot assay. These studies show that HPV-11 E6 skews IL-10-IFN-gamma expression by patients with RRP toward greater expression of IL-10 than of IFN-gamma. In addition, there is a general cytokine hyporesponsiveness to E6 that is more prominent for T(H)1-like cytokine expression by patients with severe disease. Patients showed persistent IL-10 cytokine expression by the nonadherent fraction of PBMC when challenged with E6 and tat-E6, and, in contrast to controls, both T cells and non-T cells from patients expressed IL-10. However, E7/tat-E7 cytokine responses in patients with RRP were similar to those of the controls. In contrast, E6 inhibited IL-2 and IL-18 mRNA expression that would further contribute to a cytokine microenvironment unfavorable to HPV-specific, T-cell responses that should control persistent HPV infection. In summary, E6 is the dominant inducer of cytokine expression in RRP, and it induces a skewed expression of IL-10 compared to the expression of IFN-gamma.

HLA alleles, IFN-gamma responses to HPV-11 E6, and disease severity in patients with recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) remains an immunologic enigma. Human papillomavirus (HPV) types 6 and 11 are the predominant HPV viruses that cause papilloma development. However, it is unclear why only a very small fraction of HPV-exposed individuals develop RRP. We performed high-resolution HLA class I and II genotyping on 70 randomly selected patients (56 Caucasians and 14 African-Americans) with RRP. We report, for the first time, an increased frequency of HLA-DRB1*0102 in Caucasian patients with RRP, suggesting that this allele predisposes individuals to RRP. Additionally, HLA-DRB1*0301, DQB1*0201, and DQB1*0202 alleles were selectively enriched in Caucasians with severe disease, suggesting that these alleles may regulate disease severity. In contrast, HLA-DQB1*0602 was more frequent in controls than in Caucasians with severe disease, suggesting a severity-sparing effect of this allele. Furthermore, both DQB1*0201 and DQB1*0202 were enriched, whereas DQB1*0602 was absent, in African-Americans. Interestingly, HLA-DRB1*0301 and DQB1*0201 correlated with reduced interferon-gamma expression in patients with RRP. Larger studies are needed to identify other class II major histocompatibility complex alleles that may influence disease predisposition, disease severity, or both, especially in African-American patients, to ultimately illuminate the regulatory effects of these alleles in the predisposition and severity of RRP.

Polymorphism of transporter associated with antigen presentation 1 as a potential determinant for severity of disease in recurrent respiratory papillomatosis caused by human papillomavirus types 6 and 11

Recurrent respiratory papillomatosis (RRP) is a rare disease caused by human papillomaviruses (HPVs). It is characterized by multiple recurrences of benign neoplasms and has a variable clinical course, ranging from infrequent recurrence to acute airway obstruction. One way in which HPV subverts the immune system in RRP is by interfering with TAP1 (transporter associated with antigen presentation 1). We examined whether a known TAP1 polymorphism in the ATPase domain altered the severity of disease in patients with RRP. The presence of this polymorphism was significantly correlated with severity of disease (P=.015). Because of the proximity of the TAP1 gene to human leukocyte antigen (HLA) class II genes on chromosome 6, we postulated that a linkage disequilibrium may exist. Of the patients with polymorphic TAP1, 36% were positive for HLA-DRB1*0102 (P=.021; P=.147 with Bonferroni's correction). However, this association appeared to mitigate the severity of disease (P=.04). Therefore, severity of disease in a patient with RRP might be determined by sequencing TAP1, in conjunction with HLA class II genes.

Latent human papillomavirus infection is comparable in the larynx and trachea

Recurrent respiratory papillomas are benign airway tumors caused by Human Papillomaviruses (HPVs) types 6 and 11. The disease is characterized by multiple recurrences of papillomas following surgical removal, caused by activation of latent HPV DNA. Most patients have laryngeal disease, while only a small subset has tracheal involvement. We have asked whether the lower frequency of tracheal papillomas was due to reduced prevalence of latent/subclinical tracheal HPV infection or reduced likelihood of activation to clinically apparent disease. A total of 121 biopsies of clinically normal laryngeal and tracheal tissues from 61 patients with laryngeal papillomas were analyzed for HPV DNA by polymerase chain reaction, confirmed by Southern blot hybridization. Patients were followed for 3-18 years (mean = 5.5 +/- 4.4), with only one developing subsequent tracheal disease. There was no significant difference in prevalence of latent HPV DNA between larynx and trachea, analyzing either those patients with a single biopsy or those with more than one biopsy of larynx, trachea, or both. There was also no significant difference between tracheal latency with HPV 6 and HPV 11. We conclude that HPV infects tracheal mucosa and is maintained as a latent infection in the trachea as efficiently as in the larynx. Therefore, we propose that the low frequency of tracheal disease reflects a lower frequency of HPV activation, and postulate that cellular factors that differ between the stratified squamous epithelium of the larynx and the ciliated pseudo-stratified columnar epithelium of the trachea contribute to this difference.

Requirement of STAT3 activation for differentiation of mucosal stratified squamous epithelium

STAT3, a member of the signal transducers and activators of transcription (STAT) family, has been shown to play a key role in promoting proliferation, differentiation, or cell cycle progression, depending on cell type. A number of signaling pathways are altered in laryngeal papillomas, benign tumors induced by human papillomavirus 6/11. Papillomas overexpress the epidermal growth factor receptor and display enhanced MAP kinase and PI-3-kinase activity. They also show reduced activation of Akt and reduced levels of tyrosine-phosphorylated STAT3, due to overexpression of the tumor suppressor, PTEN. As papillomas show abnormalities in terminal differentiation, we examined the potential role of STAT3 in regulating epithelial differentiation. Laryngeal epithelial cells were suspended in supplemented serum-free medium. Differentiation was measured by Western blot analysis of keratin 13. Normal laryngeal epithelial cells were transfected with a constitutively active STAT3 or a dominant negative STAT3. Cells were transferred to suspension culture 24 h after transfection. Increased expression of keratin 13 was accompanied by the activation of STAT3 when differentiation was induced, and expression of a constitutively active STAT3 (STAT3C) enhanced the expression of keratin 13. In contrast, expression of a dominant negative STAT3 (Y705F) inhibited the expression of keratin 13. We conclude that activation of STAT3 is required for the differentiation of normal human stratified squamous epithelium.

PTEN is a negative regulator of STAT3 activation in human papillomavirus-infected cells

Laryngeal papillomas are caused by infection of the laryngeal epithelium by human papillomavirus type 6 or type 11 (HPV-6/-11). Previous studies in our laboratory have demonstrated an increase in PI3 kinase levels in papilloma tissue. However, activation of the downstream effector of PI3 kinase, protein kinase B (PKB/Akt), was reduced. This observation was explained by the elevated expression of the phosphatase and tensin homologue (PTEN), a recently characterized tumour suppressor, in papilloma tissue. Recent investigation of the possible functional roles of PTEN during papilloma development has now indicated that the level of tyrosine(705)-phosphorylated signal transducer and activator of transcription 3 [PTyr(705)STAT3] could be inversely correlated to that of PTEN as well. In vitro phosphatase assays suggested the presence of an increased level of a PTyr(705)STAT3 phosphatase in papilloma extract. Immunodepletion of PTEN from papilloma extracts resulted in a reduction of the PTyr(705)STAT3 phosphatase activity. Transfection of PTEN cDNA into HeLa cells attenuated STAT3 phosphorylation at Tyr(705) in a dose-dependent manner. This attenuation of STAT3 phosphorylation was independent of the STAT3 kinase. Interestingly, introduction of a lipid phosphatase mutant of PTEN (G129E) resulted in heightened PTyr(705)STAT3 phosphatase activity, relative to that obtained from wild-type PTEN transfection. These data indicate that PTEN negatively regulates STAT3 activation in HPV-infected papilloma cells. Induction of PTEN and reduction of activated STAT3 might be a result of a host defence mechanism or a virus-directed strategy to alter normal epithelial differentiation programming.

Interaction of human papillomavirus type 11 E7 protein with TAP-1 results in the reduction of ATP-dependent peptide transport

Human papillomaviruses (HPVs) cause benign and malignant epithelial tumors of the respiratory and genital mucosa. We previously reported that recurrent respiratory papillomas caused by HPV 6/11 express low levels of antibody-detectable TAP-1, the protein that transports peptides into the endoplasmic reticulum for assembly and presentation by MHC Class I, and that the extent of TAP-1 immunostaining is inversely related to the frequency of disease recurrence. We have now determined a mechanism for the reduction in TAP-1 detection. Anti-TAP-1 antibody immunoprecipitated very low amounts of protein from papilloma cells. However, immunoprecipitation of calreticulin, another member of the MHC I assembly complex, coprecipitated TAP-1 at levels comparable to those of uninfected cells. Immunoprecipitation of an HPV-positive cell line with either anti-TAP-1 or anti-calreticulin coprecipitated HPV E7 protein. Finally, purified HPV 11 E7 protein inhibited ATP-dependent peptide transport in vitro. We propose that the interaction of E7 with TAP-1 prevents TAP-1 antibody detection and efficient peptide transport, resulting in poor presentation of viral antigen on HPV-infected cells and thus failure to mount an effective immune-mediated prevention of disease recurrence.

Minimally invasive aortic valve replacement: echocardiographic and clinical results

BACKGROUND

Port access has been described for mitral and bypass surgery. The purpose of this study was to review the clinical and echocardiographic outcomes of aortic valve replacement by use of port access.

METHODS

Between 1996 and 1999, 153 port-access aortic valve replacements were performed at our institution. The mean age was 63 years (range 16-91 years); 58% were male. The New York Heart Association mean class was III; 18% were in class IV. Thirteen percent had diabetes, 42% hypertension, 7% prior transient ischemic episode or stroke, 7% lung disease, 3% renal failure, and 13% previous surgery. Echocardiograms were obtained after valve replacement in 125 patients (96 intraoperative transesophageal and 97 transthoracic echoes).

RESULTS

Median length of stay was 8 days. There were no intraoperative deaths; 10 patients (6.5%) died in the postoperative period. Stroke occurred in 4 (2.6%), sepsis in 5 (3.3%), renal failure in 5 (3.3%), pneumonia in 3 (2%), and wound infection in 1 (0.7%). Tissue prosthesis was present in 83 and a mechanical prosthesis in 42. No or trace regurgitation was seen on 94 of 96 (98%) postbypass intraoperative echocardiograms and mild on 2. On follow-up echocardiograms, moderate regurgitation was seen in 4 of 97 (4.1%), mild-to-moderate in 2 (2.1%), mild in 18 (18.6%), and no or trace in 71 (73.2%). Of those who had aortic regurgitation on intraoperative or follow-up echocardiograms, it was paravalvular in 8.

CONCLUSIONS

Minimally invasive aortic valve replacement with a port-access approach is feasible, even in high-risk patients. Small incisions, a low infection rate, and a short length of stay are attainable. However, the complications associated with traditional aortic valve replacement still occur. Echocardiography is valuable both for intraoperative monitoring and follow-up of this new procedure.

Minimally invasive versus sternotomy approaches for mitral reconstruction: comparison of intermediate-term results

BACKGROUND

This study compares intermediate-term outcomes of mitral valve reconstruction after either the standard sternotomy approach or the new minimally invasive approach. Although minimally invasive mitral valve operations appear to offer certain advantages, such as reduced postoperative discomfort and decreased postoperative recovery time, the intermediate-term functional and echocardiographic efficacy has not yet been documented.

METHODS

From May 1996 to February 1999, 100 consecutive patients underwent primary mitral reconstruction through a minimally invasive right anterior thoracotomy and peripheral cardiopulmonary bypass and Port-Access technology (Heartport, Inc, Redwood City, Calif). Outcomes were compared with those for our previous 100 patients undergoing primary mitral repair who were operated on with the standard sternotomy approach.

RESULTS

Although patients were similar in age, the patients undergoing the minimally invasive approach had a lower preoperative New York Heart Association classification (2.1 +/- 0.5 vs 2.6 +/- 0.6, P <.001). There was one (1.0%) hospital mortality with the sternotomy approach and no such case with the minimally invasive approach. Follow-up revealed that residual mitral insufficiency was similar between the minimally invasive and sternotomy approaches (0.79 +/- 0.06 vs 0.77 +/- 0.06, P =.89, 0- to 3-point scale); likewise, the cumulative freedom from reoperation was not significantly different (94.4% vs 96.8%, P =.38). Follow-up New York Heart Association functional class was significantly better in the patients undergoing the minimally invasive approach (1.5 +/- 0.05 vs 1.2 +/- 0.05, P <.01).

CONCLUSIONS

These findings demonstrate comparable 1-year follow-up results after minimally invasive mitral valve reconstruction. Both echocardiographic results and New York Heart Association functional improvements were compatible with results achieved with the standard sternotomy approach. The minimally invasive approach for mitral valve reconstruction provides equally durable results with marked advantages for the patient and should be more widely adopted.