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

Preclinical Models of Laryngeal Papillomavirus Infection: A Scoping Review

OBJECTIVE

Laryngeal human papillomavirus (HPV) infection causes recurrent respiratory papillomatosis (RRP) and accounts for up to 25% of laryngeal cancers. Lack of satisfactory preclinical models is one reason that treatments for these diseases are limited. We sought to assess the literature describing preclinical models of laryngeal papillomavirus infection.

DATA SOURCES

PubMed, Web of Science, and Scopus were searched from the inception of database through October 2022.

REVIEW METHODS

Studies searched were screened by two investigators. Eligible studies were peer-reviewed, published in English, presented original data, and described attempted models of laryngeal papillomavirus infection. Data examined included type of papillomavirus, infection model, and results including success rate, disease phenotype, and viral retention.

RESULTS

After screening 440 citations and 138 full-text studies, 77 studies published between 1923 and 2022 were included. Models used low-risk HPV or RRP (n = 51 studies), high-risk HPV or laryngeal cancer (n = 16), both low- and high-risk HPV (n = 1), and animal papillomaviruses (n = 9). For RRP, 2D and 3D cell culture models and xenografts retained disease phenotypes and HPV DNA in the short term. Two laryngeal cancer cell lines were consistently HPV-positive in multiple studies. Animal laryngeal infections with animal papillomaviruses resulted in disease and long-term retention of viral DNA.

CONCLUSIONS

Laryngeal papillomavirus infection models have been researched for 100 years and primarily involve low-risk HPV. Most models lose viral DNA after a short duration. Future work is needed to model persistent and recurrent diseases, consistent with RRP and HPV-positive laryngeal cancer.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:3256-3268, 2023.

Patient-Derived Organotypic Epithelial Rafts Model Phenotypes in Juvenile-Onset Recurrent Respiratory Papillomatosis

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is driven by human papillomavirus (HPV) low-risk strains and is associated with significant morbidity. While previous studies of 2D cultures have shed light on disease pathogenesis and demonstrated the utility of personalized medicine approaches, monolayer cultures lack the 3D tissue architecture and physiology of stratified, sequentially differentiated mucosal epithelium important in RRP disease pathogenesis. Herein we describe the establishment of JoRRP-derived primary cell populations that retain HPV genomes and viral gene expression in culture. These were directly compared to cells from matched adjacent non-diseased tissue, given the known RRP patient-to-patient variability. JoRRP papilloma versus control cells displayed decreased growth at subconfluency, with a switch to increased growth after reaching confluency, suggesting relative resistance to cell-cell contact and/or differentiation. The same papilloma cells grown as 3D organotypic rafts harbored hyperproliferation as compared to controls, with increased numbers of proliferating basal cells and inappropriately replicating suprabasal cells, mimicking phenotypes in the patient biopsies from which they were derived. These complementary model systems provide novel opportunities to elucidate disease mechanisms at distinct stages in JoRRP progression and to identify diagnostic, prognostic and therapeutic factors to personalize patient management and treatment.

COX-2 Overexpression in Schneiderian Papillomas

Background

Schneiderian papillomas (SP) are aggressive sinonasal tumors that occasionally extend into areas that are surgically unresectable.

Objective

evaluate the signifcance of cyclo-oxygenase-2 (COX-2) expression in SP.

Methods

Immunohistochemistry for COX-2 was performed on SP samples and middle turbinates from chronic rhinosinusitis without nasal polyps controls obtained during surgical resection between 2009–2017. A positive stain was defined as having 10% or more cells exhibiting diffuse immunoreactivity. Comparisons were performed using Fisher Exact tests, t-tests, and ANOVA.

Results

The study included 67 tumor samples and 9 controls from two academic institutions. The mean age of the SP group was 55.4 years and 53.2 years in the control group (p = 0.71). Thirty-nine (58.2%) SP patients had previous surgery compared to 1 (11.1%) in the control group (p = 0.01). The most common tumor attachment sites were the maxillary (47.8%) and ethmoid (25.4%) sinuses. Fifteen (22.4%) SP samples stained strongly positive for COX-2 and 24 (35.8%) stained weakly positive compared to no positive stains in the control group (p < 0.01). When stratified by COX-2 intensity, there were no statistically significant differences in gender, smoking history, history of previous sinus surgery, site of attachment, papilloma subtype, or future recurrence between SP samples.

Conclusion

COX-2 was overexpressed in 58.2% of SP cases, and strongly positive in 22.4% of cases, compared to no positive staining among controls. No significant differences in COX-2 expression were observed between SP subtypes or recurrent tumors. Further studies are warranted to evaluate COX-2 as a possible therapeutic target in tumors that overexpress the enzyme.

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.

Mitochondrial somatic mutations and the lack of viral genomic variation in recurrent respiratory papillomatosis

Recurrent Respiratory Papillomatosis (RRP) is a rare disease of the aerodigestive tract caused by the Human Papilloma Virus (HPV) that manifests as profoundly altered phonatory and upper respiratory anatomy. Current therapies are primarily symptomatic; enhanced insight regarding disease-specific biology of RRP is critical to improved therapeutics for this challenging population. Multiplex PCR was performed on oral rinses collected from twenty-three patients with adult-onset RRP every three months for one year. Twenty-two (95.6%) subjects had an initial HPV positive oral rinse. Of those subjects, 77.2% had an additional positive oral rinse over 12 months. A subset of rinses were then compared to tissue samples in the same patient employing HPViewer to determine HPV subtype concordance. Multiple HPV copies (60–787 per human cell) were detected in RRP tissue in each patient, but a single dominant HPV was found in individual samples. These data confirm persistent oral HPV infection in the majority of patients with RRP. In addition, three novel HPV6 isolates were found and identical HPV strains, at very low levels, were identified in oral rinses in two patients suggesting potential HPV subtype concordance. Finally, somatic heteroplasmic mtDNA mutations were observed in RRP tissue with 1.8 mutations per sample and two nonsynonymous variants. These data provide foundational insight into both the underlying pathophysiology of RRP, but also potential targets for intervention in this challenging patient cohort.

Autocrine STAT3 activation in HPV positive cervical cancer through a virus-driven Rac1-NFκB-IL-6 signalling axis

Persistent human papillomavirus (HPV) infection is the leading cause of cervical cancer. Although the fundamental link between HPV infection and oncogenesis is established, the specific mechanisms of virus-mediated transformation are not fully understood. We previously demonstrated that the HPV encoded E6 protein increases the activity of the proto-oncogenic transcription factor STAT3 in primary human keratinocytes; however, the molecular basis for STAT3 activation in cervical cancer remains unclear. Here, we show that STAT3 phosphorylation in HPV positive cervical cancer cells is mediated primarily via autocrine activation by the pro-inflammatory cytokine Interleukin 6 (IL-6). Antibody-mediated blockade of IL-6 signalling in HPV positive cells inhibits STAT3 phosphorylation, whereas both recombinant IL-6 and conditioned media from HPV positive cells leads to increased STAT3 phosphorylation within HPV negative cervical cancer cells. Interestingly, we demonstrate that activation of the transcription factor NFκB, involving the small GTPase Rac1, is required for IL-6 production and subsequent STAT3 activation. Our data provides new insights into the molecular re-wiring of cancer cells by HPV E6. We reveal that activation of an IL-6 signalling axis drives the autocrine and paracrine phosphorylation of STAT3 within HPV positive cervical cancers cells and that activation of this pathway is essential for cervical cancer cell proliferation and survival. Greater understanding of this pathway provides a potential opportunity for the use of existing clinically approved drugs for the treatment of HPV-mediated cervical cancer.

Poly(I:C) induces controlled release of IL-36γ from keratinocytes in the absence of cell death

The epithelium is part of an integrated immune system where cytokines, toll-like receptors and their ligands, and extracellular vesicles play a crucial role in initiating an innate immune response. IL-36γ is a pro-inflammatory member of the IL-1 family that is mainly expressed by epithelial cells, but regulation of its expression and release are only beginning to be understood. Previous studies reported that IL-36γ is abundant in recurrent respiratory papillomatosis, a rare but devastating disease caused by human papillomaviruses (HPV) types 6 and 11, in which papillomas recurrently grow in and block the airway. Despite the overexpression of IL-36γ, papilloma tissues show no evidence of inflammation, possibly due to suppression of its release by HPVs. We have used primary human foreskin keratinocytes as a model to study IL-36γ regulation in normal epithelial cells. Low doses of poly(I:C) mediate expression and release of IL-36γ without inducing the cell death reported by those using high doses. PKR, an enzyme required for inflammasome activation, does not contribute to controlled release of IL36γ. The keratinocytes secrete IL-36γ in two forms, soluble and in extracellular vesicles. We conclude that there are two separately regulated pathways for the controlled secretion of IL-36γ from keratinocytes, which could contribute to the modulation of both local and systemic immune responses to viruses and other pathogens.

Differences in Transcriptional Activity of Human Papillomavirus Type 6 Molecular Variants in Recurrent Respiratory Papillomatosis

A significant proportion of recurrent respiratory papillomatosis (RRP) is caused by human papillomavirus type 6 (HPV-6). The long control region (LCR) contains cis-elements for regulation of transcription. Our aim was to characterize LCR HPV-6 variants in RRP cases, compare promoter activity of these isolates and search for cellular transcription factors (TFs) that could explain the differences observed. The complete LCR from 13 RRP was analyzed. Transcriptional activity of 5 variants was compared using luciferase assays. Differences in putative TFs binding sites among variants were revealed using the TRANSFAC database. Chromatin immunoprecipation (CHIP) and luciferase assays were used to evaluate TF binding and impact upon transcription, respectively. Juvenile-onset RRP cases harbored exclusively HPV-6vc related variants, whereas among adult-onset cases HPV-6a variants were more prevalent. The HPV-6vc reference was more transcriptionally active than the HPV-6a reference. Active FOXA1, ELF1 and GATA1 binding sites overlap variable nucleotide positions among isolates and influenced LCR activity. Furthermore, our results support a crucial role for ELF1 on transcriptional downregulation. We identified TFs implicated in the regulation of HPV-6 early gene expression. Many of these factors are mutated in cancer or are putative cancer biomarkers, and must be further studied.

Risk factors for adult-onset recurrent respiratory papillomatosis

OBJECTIVES/HYPOTHESIS

To evaluate risk factors strongly associated with adult-onset recurrent respiratory papillomatosis (AO-RRP).

STUDY DESIGN

Prospective, age- and sex-matched, case control.

METHODS

Patients with AO-RRP and controls completed a computer-based, 89-item questionnaire across three academic institutions.

RESULTS

Forty-eight AO-RRP patients were compared to 73 controls; 43 of the 48 AO-RRP patients were male (89.5%). The difference in the median number of lifetime sexual partners between AO-RRP (15) and controls (10) was significant (P = 0.0387). Additionally, an increased number of lifetime sexual partners (≥ 26) was associated with AO-RRP. No significant difference for the number of lifetime oral sex partners was observed between groups. Increased comorbidity, as quantified by the Charlson Comorbidity Index, was observed in patients with AO-RRP. AO-RRP and control groups were similar across many other variables, including birth history, smoking history, alcohol use, drug use, education, income, and the Short Form Health Survey scores.

CONCLUSIONS

AO-RRP was not associated with previously proposed risk factors for juvenile-onset RRP and may be associated with an increased number of lifetime sexual partners.

COX-(2) overexpression in sinonasal inverted papilloma

BACKGROUND

Inverted papilloma (IP) is a benign, but locally aggressive neoplasm of the nasal cavity and paranasal sinuses. The mainstay of treatment of IP is surgical resection, but high rates of tumor recurrence have been reported. Cyclo-oxygenase-2 (COX-2) has been found to be overexpressed in many tumors and has been used successfully as a therapeutic target. The goal of this study is to highlight COX-2 expression in IP.

METHODS

Immunohistochemistry for COX-2 was performed on IP samples obtained during surgical resection between January 2012 and June 2013. The intensity of staining was evaluated by 2 head and neck pathologists blinded to the clinical features and outcomes. A positive stain was defined as having 10% or more of tumor cells exhibiting immunoreactivity.

RESULTS

The study includes 13 tumor samples from 7 females and 6 males. Mean age was 54.5 (range, 18-81) years. Tumor locations included: nasal septum (1), ethmoid (3), sphenoid (4), and maxillary (5) sinuses. No tumors demonstrated malignancy or dysplasia. Five (38%) of the 13 IP samples stained strongly positive for COX-2, and 3 of 13 (23%) stained weakly positive. There were no clinical differences in patients that stained strongly or weakly for COX-2.

CONCLUSION

COX-2 overexpression was identified in 62% of cases of IP in this study, and strongly positive in 38% of cases. Larger studies are necessary to identify the true incidence of COX-2 expression for this tumor. Pharmaceuticals targeting COX-2 may eventually provide an additional therapeutic option for select cases of recurrent or unresectable IP.

Prevalence of diabetes mellitus and its impact on disease severity in adult recurrent respiratory papillomatosis

OBJECTIVES

Following human papilloma virus (HPV) infection, recurrent respiratory papillomatosis (RRP) develops secondary to dysfunction of innate and adaptive immune responses. Diabetes mellitus (DM) is a common medical disorder; these patients are considered to be relatively immunocompromised. It is hypothesized that comorbid DM occurs more frequently than expected in a cohort of adult RRP patients and that RRP patients with DM have more severe disease than those without DM.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary care laryngology practice, 5-year period.

SUBJECTS AND METHODS

Adult-onset RRP patients from 2007 to 2012 at the University of Washington were reviewed. The gender, age of onset of RRP, number of interventions, pathology, presence or absence of DM, and calculated anatomic Derkay severity score were recorded.

RESULTS

Eighty-four adult RRP patients were characterized; 64 male (76%) and 20 female (24%). Six of 84 patients (7.1%) had DM; this prevalence was not higher than an age-matched general population. The number of interventions required for disease control did not significantly differ (P = .13) between adult RRP patients with DM (avg 2.6/yr, median 2.3/year) and those without DM (avg 1.9/yr, median 1.3/yr). There was no significant difference in anatomic Derkay score at the time of intervention (P = .26) or presence of dysplasia in biopsy specimens (P = .49) between RRP patients with and without DM.

CONCLUSIONS

In this large series of adult RRP patients, DM does not appear to have a higher prevalence than that seen in age-matched controls, nor do RRP patients with DM appear to have more severe disease.

Rare case of malignant transformation of recurrent respiratory papillomatosis associated with human papillomavirus type 6 infection and p53 overexpression

Recurrent respiratory papillomatosis (RRP), a chronic upper respiratory condition characterized by diffuse multiple recurring papillomas, is thought to result from human papillomavirus (HPV) type 6 or 11 infection. Although RRP is an intractable disease, malignant transformation of RRP is rare. The underlying mechanism, however, has not been elucidated. We describe the clinical course of a patient who underwent more than 130 operations for RRP associated with HPV type 6 infection and subsequently suffered spontaneous malignant transformation to squamous cell carcinoma. Immunohistochemical analysis revealed that malignant transformation might result from a genomic defect, such as p53 inactivation, leading to stimulation of uncontrolled cell proliferation by HPV type 6 for an extended period, but not directly because of HPV itself. Our results could help in the development of novel therapeutic strategies for severe RRP, although further studies are required before clinical application of molecular targeted therapies.

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.

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.