Stéphanie Demoulin

Immune Suppression in Head and Neck Cancers: A Review

Head and neck squamous cell carcinomas (HNSCCs) are the sixth most common cancer in the world. Despite significant advances in the treatment modalities involving surgery, radiotherapy, and concomitant chemoradiotherapy, the 5-year survival rate remained below 50% for the past 30 years. The worse prognosis of these cancers must certainly be link to the fact that HNSCCs strongly influence the host immune system. We present a critical review of our understanding of the HNSCC escape to the antitumor immune response such as a downregulation of HLA class I and/or components of APM. Antitumor responses of HNSCC patients are compromised in the presence of functional defects or apoptosis of T-cells, both circulating and tumor-infiltrating. Langerhans cells are increased in the first steps of the carcinogenesis but decreased in invasive carcinomas. The accumulation of macrophages in the peritumoral areas seems to play a protumoral role by secreting VEGF and stimulating the neoangiogenesis.

Tumor microenvironment converts plasmacytoid dendritic cells into immunosuppressive/tolerogenic cells: insight into the molecular mechanisms

Human pDCs represent a rare population of circulating cells characterized by a rapid and massive TLR‐dependent secretion of type I IFN in response to pathogenic agents or danger signals. Through their capacity to bring together innate and adaptive immunity and to secrete soluble factors controlling cancer development, these cells could represent important actors in antitumor immunity. However, accumulating evidence suggests that pDCs recruited to the tumor microenvironment often display a nonactivated state and are associated with the development and maintenance of immunosuppression. Here, we present an overview of neoplastic lesions associated with an infiltration of immunosuppressive/tolerogenic pDC. Moreover, as the proper response of pDC against cancer depends on a critical balance between immune‐activating and immune‐suppressing mechanisms, we summarize current knowledge about the molecular pathways developed by tumors to prevent antitumoral pDC immune responses. A better understanding of the mechanisms regulating pDC function in tumors could aid in the development of new therapies. Indeed, effective cancer vaccines or therapies could combine immunoactivating strategies (i.e., TLR agonists) with elimination of immune‐suppressing mechanisms, leading to pDC reprogramming and thus, allowing tumor rejection in a clinical setting.

Carcinogenic HPV infection in the cervical squamo-columnar junction

Recent studies have suggested the involvement of a unique population of cells at the cervical squamo‐columnar junction (SCJ) in the pathogenesis of early (squamous intraepithelial lesion or SIL) and advanced (squamous cell and adeno‐carcinomas) cervical neoplasia. However, there is little evidence to date showing that SCJ cells harbour carcinogenic HPV or are instrumental in the initial phases of neoplasia. This study was designed to (1) determine if normal‐appearing SCJ cells contained evidence of carcinogenic HPV infection and (2) trace their transition to early SIL. Sections of cervix from high‐risk reproductive age women were selected and SCJ cells were analysed by using several techniques which increasingly implicated HPV infection: HPV DNA (genotyping and in situ hybridization)/RNA (PCR), immunostaining for HPV16 E2 (an early marker of HPV infection), p16ink4, Ki67, and HPV L1 protein. In 22 cases with a history of SIL and no evidence of preneoplastic lesion in the excision specimen, HPV DNA was isolated from eight of ten with visible SCJ cells, six of which were HPV16/18 DNA‐positive. In five of these latter cases, the SCJ cells were positive for p16ink4 and/or HPV E2. Transcriptionally active HPV infection (E6/E7 mRNAs) was also detected in microdissected SCJ cells. Early squamous atypia associated with the SCJ cells demonstrated in addition diffuse p16ink4 immunoreactivity, elevated proliferative index, and rare L1 antigen positivity. We present for the first time direct evidence that normal‐appearing SCJ cells can be infected by carcinogenic HPV. They initially express HPV E2 and their progression to SIL is heralded by an expanding metaplastic progeny with increased proliferation and p16ink4 expression. Whether certain SCJs are more vulnerable than others to carcinogenic HPV genotypes and what variables determine transition to high‐grade SIL remain unresolved, but the common event appears to be a vulnerable cell at the SCJ. Copyright

A Clinical and Pathological Overview of Vulvar Condyloma Acuminatum, Intraepithelial Neoplasia, and Squamous Cell Carcinoma

Condyloma acuminatum, intraepithelial neoplasia, and squamous cell carcinoma are three relatively frequent vulvar lesions. Condyloma acuminatum is induced by low risk genotypes of human papillomavirus (HPV). Vulvar intraepithelial neoplasia (VIN) and squamous cell carcinoma have different etiopathogenic pathways and are related or not with high risk HPV types. The goal of this paper is to review the main pathological and clinical features of these lesions. A special attention has been paid also to epidemiological data, pathological classification, and clinical implications of these diseases.

Altered alpha-defensin 5 expression in cervical squamocolumnar junction: implication in the formation of a viral/tumour-permissive microenvironment

Human papillomavirus (HPV) infection, particularly type 16, is causally associated with cancer of the uterine cervix, which mainly develops at the squamocolumnar (SC) junction. The progression of cervical HPV infections into (pre)neoplastic lesions suggests that viral antigens are not adequately recognized by innate immunity or presented to the adaptive immune system. Members of the defensin family have recently been found to inhibit viral and bacterial pathogens, to stimulate the migration of immune cells and to play a role in anticancer responses. In the present study, we focused on the poorly characterized human α‐defensin 5 (HD‐5) and its possible role in these processes. We showed that HD‐5 was able to prevent HPV virion entry into cervical keratinocytes and to influence adaptive immunity. Indeed, this peptide specifically induced the chemoattraction and proliferation of both activated T lymphocytes and immature dendritic cells in a CCR2/CCR6‐dependent manner and stimulated the infiltration of these professional antigen‐presenting cells in a (pre)neoplastic epithelium transplanted in vivo in immunodeficient mice. No chemotactic effect was observed with plasmacytoid dendritic cells, macrophages or natural killer cells. Proliferative and angiogenic effects of HD‐5 were also assessed in vitro and in vivo. However there was a striking regional disparity in expression of HD‐5, being prominent in ectocervical, vaginal and vulvar neoplasia, while absent, or nearly so, in the cervical SC junction. Taken together, these results suggest one possible explanation for why the SC junction is uniquely vulnerable to both high‐risk HPV infection (via reduced HD‐5 expression and viral entry) and progression of neoplasia (via altered cell‐mediated immune responses and altered microenvironment). Copyright

Cervical (pre)neoplastic microenvironment promotes the emergence of tolerogenic dendritic cells via RANKL secretion.

The progression of genital human papillomavirus (HPV) infections into preneoplastic lesions suggests that infected/malignant cells are not adequately recognized by the immune system. In this study, we demonstrated that cervical/vulvar cancer cells secrete factor(s) that affect both the maturation and function of dendritic cells (DC) leading to a tolerogenic profile. Indeed, DC cocultured with cancer cell lines display both a partially mature phenotype after lipopolysaccharide (LPS) maturation and an altered secretory profile (IL-10high and IL-12p70low). In addition, tumor-converted DC acquire the ability to alter T-cell proliferation and to induce FoxP3+ suppressive T cells from naive CD4+ T cells. Among the immunosuppressive factors implicated in DC alterations in genital (pre)neoplastic microenvironment, we identified receptor activator of nuclear factor kappa-B ligand (RANKL), a TNF family member, as a potential candidate. For the first time, we showed that RANKL expression strongly increases during cervical progression. We also confirmed that RANKL is directly secreted by cancer cells and this expression is not related to HPV viral oncoprotein induction. Interestingly, the addition of osteoprotegerin (OPG) in coculture experiments reduces significantly the inhibition of DC maturation, the release of a tolerogenic cytokine profile (IL-12low IL-10high) and the induction of regulatory T (Treg) cells. Our findings suggest that the use of inhibitory molecules directed against RANKL in cervical/vulvar (pre)neoplastic lesions might prevent alterations of DC functionality and represent an attractive strategy to overcome immune tolerance in such cancers.

Dendritic cells in Barrett's esophagus carcinogenesis: an inadequate microenvironment for antitumor immunity?

Barretts esophagus corresponds to the replacement of the normal esophageal squamous epithelium by a columnar epithelium through a metaplastic process. This tissue remodeling is associated with chronic gastroesophageal reflux and constitutes a premalignant lesion leading to a 30- to 60-fold increase in the risk to evolve into esophageal adenocarcinoma. The present study aimed to investigate a possible immune evasion in Barretts esophagus favoring esophageal adenocarcinoma development. We demonstrated that myeloid and plasmacytoid dendritic cells are recruited during the esophageal metaplasia-dysplasia-carcinoma sequence, through the action of their chemoattractants, macrophage inflammatory protein 3α and chemerin. Next, we showed that, in contrast to plasmacytoid dendritic cells, myeloid dendritic cells, co-cultured with Barretts esophagus and esophageal adenocarcinoma cell lines, display a tolerogenic phenotype. Accordingly, myeloid dendritic cells co-cultured with esophageal adenocarcinoma cell lines stimulated regulatory T cell differentiation from naïve CD4(+) T cells. In agreement with those results, we observed that both metaplastic areas and (pre)malignant lesions of the esophagus are infiltrated by regulatory T cells. In conclusion, soluble factors secreted by epithelial cells during the esophageal metaplasia-dysplasia-carcinoma sequence influence dendritic cell distribution and promote tumor progression by rendering them tolerogenic.

HMGB1 secretion during cervical carcinogenesis promotes the acquisition of a tolerogenic functionality by plasmacytoid dendritic cells

Acquisition of an impaired functionality by plasmacytoid dendritic cells (pDCs) contributing to cancer progression has been documented in different types of cancers. In the present study, we postulate that molecules secreted by (pre)neoplastic epithelial cells of the genital tract (cervix/vulva) might attract pDCs but also modify their proper functionality, allowing these cells to initiate a tolerogenic response interfering with antitumor immunity. We demonstrated that pDCs are recruited during the cervical metaplasia‐dysplasia‐cancer sequence, through the action of their chemoattractant, chemerin. We showed that stimulated‐pDCs exposed to cervical/vulvar tumor microenvironment display an altered phenotype. We also demonstrated that cervical/vulvar neoplastic keratinocytes inhibit the proper function of pDCs by decreasing their IFNα secretion in response to CpG oligonucleotides. In parallel, we observed that (pre)neoplastic areas of the cervix are infiltrated by FoxP3+ Treg cells which colocalize with pDCs. Accordingly, pDCs cocultured with cervical/vulvar neoplastic keratinocytes have the capacity to induce a Treg cell differentiation from naïve CD4+ T cells, which is in agreement with the development of a tolerogenic response. We identified HMGB1 as a soluble factor produced by neoplastic keratinocytes from the genital tract involved in pDCs functional alteration. Indeed, this molecule inhibited pDC maturation, decreased IFNα secretion following TLR9 stimulation and forced these cells to become tolerogenic. In contrast, inhibition of HMGB1 restored pDC phenotype. Our findings indicate that the use of inhibitory molecules notably directed against HMGB1 in cervical/vulvar (pre)neoplastic lesions might prevent alterations of pDCs functionality and represent an attractive therapeutic strategy to overcome immune tolerance in cancers.

Vulvar Skin Disorders throughout Lifetime: About Some Representative Dermatoses

The objective of this paper is to present general considerations which should be kept in mind by clinicians in charge of women with vulvar diseases. Four representative vulvar dermatoses are described. Lichen simplex chronicus is a pathological condition related to chemical and mechanical irritant agents. Detrimental effects of these irritants, in the presence of other dermatoses, have to be considered when therapeutic responses are unsatisfactory. Lichen sclerosus is the most common vulvar dermatosis in elderly. However, it should be kept in mind that it may be diagnosed at any age. Lichen planus, in spite of sharing a similar range of etiological factors with lichen sclerosus, is a very distinct entity. Finally, Pagets disease, although rare, is also described especially because of the challenge it represents both clinically and therapeutically.