Exploration of immune-related cells and ceRNA in squamous cell lung cancer.

ABSTRACT: The treatment for squamous cell lung cancer (SqCLC) is limited, and the prognosis of SqCLC is poor. In this article, we aimed to analyze and identify immune-related cells and competition endogenous RNA (ceRNA) that influence the prognosis of SqCLC. SqCLC and lung adenocarcinoma data were downloaded from TCGA-GDC. A total of 22 types of immune cell fractions were estimated using CIBERSORT. R software was used to identify any significantly different transcriptome data, including mRNA, LncRNA, and miRNA. The univariate cox regression method was applied to screen for prognosis-related lncRNA, miRNA, mRNA and tumor-infiltrating immune cells. There were 504 patients included in this study. There was a higher proportion of memory activated CD4+ T cells and CD8+ T cells in younger women. Follicular helper T (Tfh) cells were predictive of a good prognosis and reflected immune activation in SqCLC. The SFTA1P/NKX2-1-AS1, hsa-mir-503, GREM2 ceRNA axes and NKX2-1-AS1, hsa-mir-96, PROK2 ceRNA axes were found to be important for the immune function, pathogenesis, and prognosis of SqCLC. Collectively, the immune-related ceRNA and tumor-infiltrating immune cells in SqCLC are likely important determinants of SqCLC pathogenesis, prognosis, and immune status.

Consequences of Vitamin A Deficiency: Immunoglobulin Dysregulation, Squamous Cell Metaplasia, Infectious Disease, and Death.

Vitamin A is an important regulator of immune protection, but it is often overlooked in studies of infectious disease. Vitamin A binds an array of nuclear receptors (e.g., retinoic acid receptor, peroxisome proliferator-activated receptor, retinoid X receptor) and influences the barrier and immune cells responsible for pathogen control. Children and adults in developed and developing countries are often vitamin A-deficient or insufficient, characteristics associated with poor health outcomes. To gain a better understanding of the protective mechanisms influenced by vitamin A, we examined immune factors and epithelial barriers in vitamin A deficient (VAD) mice, vitamin D deficient (VDD) mice, double deficient (VAD+VDD) mice, and mice on a vitamin-replete diet (controls). Some mice received insults, including intraperitoneal injections with complete and incomplete Freund's adjuvant (emulsified with PBS alone or with DNA + Fus-1 peptide) or intranasal inoculations with Sendai virus (SeV). Both before and after insults, the VAD and VAD+VDD mice exhibited abnormal serum immunoglobulin isotypes (e.g., elevated IgG2b levels, particularly in males) and cytokine/chemokine patterns (e.g., elevated eotaxin). Even without insult, when the VAD and VAD+VDD mice reached 3-6 months of age, they frequently exhibited opportunistic ascending bacterial urinary tract infections. There were high frequencies of nephropathy (squamous cell hyperplasia of the renal urothelium, renal scarring, and ascending pyelonephritis) and death in the VAD and VAD+VDD mice. When younger VAD mice were infected with SeV, the predominant lesion was squamous cell metaplasia of respiratory epithelium in lungs and bronchioles. Results highlight a critical role for vitamin A in the maintenance of healthy immune responses, epithelial cell integrity, and pathogen control.

P16/Ki-67 Immunostaining in the Triage of Postmenopausal Women With Low-Grade Cytology Results.

OBJECTIVE: The interpretation of postmenopausal smears and the gynecological treatment of these patients can often be difficult. The objective of this study was to assess the performance of p16/Ki-67 dual-stained cytology as a triage of atypical squamous cells of undetermined significance and low-grade intraepithelial lesion cytology results in postmenopausal women. METHODS: All consecutive atypical squamous cells of undetermined significance and low-grade intraepithelial lesion smears in 1-year period were collected and p16/Ki-67 immunostaining was performed retrospectively. The results were compared with histology results or long-term cytology follow-up in cases with no biopsy. RESULTS: The sensitivity of p16/Ki-67 immunostaining for the detection of cervical intraepithelial neoplasia (CIN) 2 and CIN 3 was 57.1% and 85.0%, respectively. The specificity for the detection of CIN 2 was 94.3% and CIN 3 92.4%. Negative predictive values for the detection of CIN 2 and CIN 3 were 96.3% and 99.6%, respectively. CONCLUSIONS: Dual p16/Ki-67 immunostaining is a useful additional method in postmenopausal patients with low-grade cytology. Considering the high specificity and negative predictive value in our study, we believe that it could be helpful in avoiding unnecessary referrals to colposcopy and thus reduce the cost of the program.

Less circulating mucosal-associated invariant T cells in patients with cervical cancer.

OBJECTIVE: Mucosal-associated invariant T cells (MAITs) are important for immune defense against infectious pathogens and regulation of various inflammatory diseases. However, their roles in cancer are rarely reported. Since cervical cancer is one of the diseases involving mucosal tissue, we try to investigate the association between circulating MAITs and cervical cancer. MATERIALS AND METHODS: Blood samples were obtained from patients with cervical cancer (n = 47) and healthy individuals (n = 39). We determined phenotypic MAITs in peripheral blood mononuclear cells (PBMCs) and evaluated the percentage of MAITs in CD3+ cells by flow cytometry. The percentage of MAITs was stratified according to Federation of Gynecology and Obstetrics (FIGO) staging system in patients with cervical cancer. Progression-free survival (PFS) with respect to the amount of MAITs was also analyzed. RESULTS: The percentage of circulating MAITs in patients with cervical cancer was significantly lower than in healthy group (0.987% vs. 4.008%, p < 0.0001). In subgroup analysis, though not statistically significant, it showed a trend of lower percentage of circulating MAITs in cervical cancer patients with FIGO stage II-IV disease than in patients with FIGO stage I disease (0.4045% vs. 1.098%, p = 0.11). A trend of poor PFS in patients with lower circulating MAITs was also noted. CONCLUSION: MAITs play a crucial role in cancer immunity. The decrease of MAITs in peripheral blood is related to cervical cancer. There is a trend of lower percentage of MAITs in advanced stages and lower percentage of MAITs towards poor PFS in patients with cervical cancer.

Inhibition of squamous cancer growth in a mouse model by Staphylococcal enterotoxin B-triggered Th9 cell expansion.

Currently, therapy for squamous cancer (SqC) is unsatisfactory. Staphylococcal enterotoxin B (SEB) has strong immune regulatory activity. This study tests the hypothesis that SEB enforces the effect of immunotherapy on SqC growth in a mouse model. C3H/HeN mice and the SqC cell line squamous cell carcinoma VII were used to create an SqC mouse model. Immune cell assessment was performed by flow cytometry. Real-time RT-PCR and western blotting were used to evaluate target molecule expression. An apoptosis assay was used to assess the suppressive effect of T helper-9 (Th9) cells on the SqC cells. The results showed that immunotherapy consisting of SEB plus SqC antigen significantly inhibited SqC growth in the mice. The frequency of Th9 cells was markedly increased in the SqC tissue and mouse spleens after treatment. SEB markedly increased the levels of signal transducer and activator of transcription 5 phosphorylation and the expression of histone deacetylase-1 (HDAC1) and PU.1 (the transcription factor of the interleukin 9 (IL-9) gene) in CD4+ T cells. Exposure to SqC-specific Th9 cells markedly induced SqC cell apoptosis both in vitro and in vivo. In conclusion, the administration of SEB induces Th9 cells in SqC-bearing mice, and theseTh9 cells inhibit SqC growth.

Epithelium Expressing the E7 Oncoprotein of HPV16 Attracts Immune-Modulatory Dendritic Cells to the Skin and Suppresses Their Antigen-Processing Capacity.

Antigen presenting cells (APCs) in skin can promote either antigen-specific effector functions or antigen tolerance, and thus determine clearance or persistence of cutaneous viral infections. Human papillomavirus (HPV) infections can persist in squamous epithelium in immunocompetent individuals, and some persisting HPV infections, particularly with HPV16, promote malignant epithelial transformation. Here, we investigate whether local expression of the HPV16 protein most associated with malignant transformation, HPV16-E7, affects the phenotype and function of APC subsets in the skin. We demonstrate an expanded population of Langerhans cells in HPV16-E7 transgenic skin with distinct cell surface markers which express immune-modulatory enzymes and cytokines not expressed by cells from non transgenic skin. Furthermore, HPV16-E7 transgene expression in keratinocytes attracts new APC subsets to the epidermis. In vivo migration and transport of antigen to the draining lymph node by these APCs is markedly enhanced in HPV16-E7 expressing skin, whereas antigen-processing, as measured by proteolytic cleavage of DQ-OVA and activation of T cells in vivo by APCs, is significantly impaired. These data suggest that local expression of HPV16-E7 in keratinocytes can contribute to persisting infection with this oncogenic virus, by altering the phenotype and function of local APCs.

Enhanced Cytotoxic CD8 T Cell Priming Using Dendritic Cell-Expressing Human Papillomavirus-16 E6/E7-p16INK4 Fusion Protein with Sequenced Anti-Programmed Death-1.

The incidence of human papillomavirus (HPV)-related head and neck squamous cell carcinoma has increased in recent decades, though HPV prevention vaccines may reduce this rise in the future. HPV-related cancers express the viral oncoproteins E6 and E7. The latter inactivates the tumor suppressor protein retinoblastoma (Rb), which leads to the overexpression of p16(INK4) protein, providing unique Ags for therapeutic HPV-specific cancer vaccination. We developed potential adenoviral vaccines that express a fusion protein of HPV-16 E6 and E7 (Ad.E6E7) alone or fused with p16 (Ad.E6E7p16) and also encoding an anti-programmed death (PD)-1 Ab. Human monocyte-derived dendritic cells (DC) transduced with Ad.E6E7 or Ad.E6E7p16 with or without Ad.αPD1 were used to activate autologous CD8 CTL in vitro. CTL responses were tested against naturally HPV-infected head and neck squamous cell carcinoma cells using IFN-γ ELISPOT and [(51)Cr]release assay. Surprisingly, stimulation and antitumor activity of CTL were increased after incubation with Ad.E6E7p16-transduced DC (DC.E6E7p16) compared with Ad.E6E7 (DC.E6E7), a result that may be due to an effect of p16 on cyclin-dependent kinase 4 levels and IL-12 secretion by DC. Moreover, the beneficial effect was most prominent when anti-PD-1 was introduced during the second round of stimulation (after initial priming). These data suggest that careful sequencing of Ad.E6E7.p16 with Ad.αPD1 could improve antitumor immunity against HPV-related tumors and that p16 may enhance the immunogenicity of DC, through cyclin-dependent pathways, Th1 cytokine secretion, and by adding a nonviral Ag highly overexpressed in HPV-induced cancers.

Functionally distinct subsets of CD4⁺ regulatory T cells in patients with laryngeal squamous cell carcinoma are indicative of immune deregulation and disease progression.

CD4+ regulatory T cells (Tregs) mediate immune tolerance in laryngeal squamous cell carcinoma (LSCC). However, Tregs are functionally heterogeneous. Recently, we reported that three distinct Treg subsets (resting Tregs, activated Tregs and cytokine-secreting CD45RA-Foxp3lowCD4+ T cells) vary in the peripheral circulation of patients with head and neck squamous cell carcinoma (HNSCC); however, the potential implication of these Treg subsets in LSCC immunity is unclear. Here, we report that activated Tregs and cytokine­secreting CD45RA-Foxp3lowCD4+ T cells were increased in LSCC patients compared with healthy donors (HD) (p<0.001, p<0.001), whereas resting Tregs were decreased (p<0.001). Activated Tregs inhibited the proliferation of CD4+CD25- T cells (p<0.001) and secreted lower levels of interleukin-2 (p<0.001), interferon-γ (p<0.001) and tumor necrosis factor-α (p<0.001) compared with the cytokine-secreting CD45RA-Foxp3lowCD4+ T cells. Importantly, activated Treg prevalence was correlated with tumor stage (p=0.001) and nodal status (p=0.007). The prevalence of naïve CD4+ (p<0.001), naïve CD8+ (p=0.002), and Th1 T-cell subsets (p<0.001, p<0.001) was decreased in the LSCC patients. In conclusion, our findings showed that activated Tregs with suppressive activity are a distinct subset of Tregs in LSCC, and correlate with disease progression. Several immune system abnormalities in LSCC patients are represented by expansion of functionally activated Tregs, both in the circulation and tumor microenvironment along with decreased frequencies of naïve T-cell populations and Th1-cell populations.

Adaptive responses to dasatinib-treated lung squamous cell cancer cells harboring DDR2 mutations.

DDR2 mutations occur in approximately 4% of lung squamous cell cancer (SCC) where the tyrosine kinase inhibitor dasatinib has emerged as a new therapeutic option. We found that ERK and AKT phosphorylation was weakly inhibited by dasatinib in DDR2-mutant lung SCC cells, suggesting that dasatinib inhibits survival signals distinct from other oncogenic receptor tyrosine kinases (RTK) and/or compensatory signals exist that dampen dasatinib activity. To gain better insight into dasatinib's action in these cells, we assessed altered global tyrosine phosphorylation (pY) after dasatinib exposure using a mass spectrometry-based quantitative phosphoproteomics approach. Overlaying protein-protein interaction relationships upon this dasatinib-regulated pY network revealed decreased phosphorylation of Src family kinases and their targets. Conversely, dasatinib enhanced tyrosine phosphorylation in a panel of RTK and their signaling adaptor complexes, including EGFR, MET/GAB1, and IGF1R/IRS2, implicating a RTK-driven adaptive response associated with dasatinib. To address the significance of this observation, these results were further integrated with results from a small-molecule chemical library screen. We found that dasatinib combined with MET and insulin-like growth factor receptor (IGF1R) inhibitors had a synergistic effect, and ligand stimulation of EGFR and MET rescued DDR2-mutant lung SCC cells from dasatinib-induced loss of cell viability. Importantly, we observed high levels of tyrosine-phosphorylated EGFR and MET in a panel of human lung SCC tissues harboring DDR2 mutations. Our results highlight potential RTK-driven adaptive-resistant mechanisms upon DDR2 targeting, and they suggest new, rationale cotargeting strategies for DDR2-mutant lung SCC.

Implication of HLA-G 3' untranslated region polymorphisms in human papillomavirus infection.

Human papillomavirus (HPV) infection is involved in cervical lesion development. It interferes with host immune response and modifies the expression of human leukocyte antigen-G (HLA-G), a nonclassical HLA-I antigen with immune-inhibitory functions. We analyzed the frequencies of two HLA-G 3' untranslated region polymorphisms (14 bp ins/del, +3142C>G), involved in HLA-G modulation, in 33 condyloma acuminatum, 14 low grade squamous intraepithelial lesion and 100 invasive cervical cancer (ICC) HPV infected patients. We showed the involvement of HLA-G polymorphisms in HPV infection and lesion development, and suggested that 14 bp del allele promotes high-risk HPV infection, with del/C haplotype associated with ICC development. On the basis of these evidences, HLA-G polymorphisms could represent a risk factor in HPV positive subjects.

A six-year experience with anal cytology in women with HPV in the lower genital tract: utility, limitations, and clinical correlation.

This study assessed the utility and limitations of anal cytology as a screening method for women infected with human papilloma virus (HPV) in the lower genital tract. Furthermore, this study aimed to establish risk factors for pathological anal cytology/biopsy findings, the prevalence of anatomopathological lesions associated with positive anal brushings, and the frequency of concomitant lesions of the lower genital tract. A cross-sectional, retrospective, descriptive study in 207 women with HPV-associated lesions of the lower genital tract and 25 women with immunosuppression was carried out. Anal cytology, high resolution anoscopy, and biopsy of suspicious lesions were performed. In total, 232 anal brushings were performed: 184 (79.3%) were negative, 24 (10.34%) showed atypical squamous cells of undeterminated significance, 18 (7.7%) showed low-grade squamous intraepithelial lesions, and 6 (2.6%) showed high-grade squamous intraepithelial lesion. Cytohistological correlation was obtained for 70 cases. The sensitivity of anal cytology in detecting intraepithelial lesions was 70%, whereas the specificity was 93%. The sensitivity of the method for detecting high-grade lesions (84%) was higher, than that for detecting low-grade lesions (66%). The most frequently associated pathology was vulvar lesion. It is important to perform anal brushings in women who have had lower genital tract biopsies for HPV-associated lesions due to the high prevalence of anal lesions in such patients. Anal cytology is useful for detecting high-grade lesions but the sensitivity for detecting low-grade lesions is low. It is of the utmost importance to perform high-resolution anoscopy and biopsy in women with suspicious lesions in order to confirm the pathology.

Natural immune responses against eight oncogenic human papillomaviruses in the ASCUS-LSIL Triage Study.

Only a subset of women with human papillomavirus (HPV) infections will become seropositive, and the factors influencing seroconversion are not well understood. We used a multiplex serology assay in women with mildly abnormal cytology results to examine seroreactivity to oncogenic HPV genotypes. An unbiased subset of women in the atypical squamous cell of undetermined significance /low-grade squamous intraepithelial lesion Triage Study provided blood samples at trial enrollment for serological testing. A Luminex assay based on glutathione s-transferase-L1 fusion proteins as antigens was used to test seroreactivity against eight carcinogenic HPV genotypes (16, 18, 31, 33, 35, 45, 52 and 58). We analyzed the relationship between seroprevalence in women free of precancer (N = 2,464) and HPV DNA status, age, sexual behavior and other HPV-related risk factors. The overall seroprevalence was 24.5% for HPV16 L1 and ∼20% for 18L1 and 31L1. Among women free of precancer, seroprevalence peaked in women less than 29 years and decreased with age. Type-specific seroprevalence was associated with baseline DNA detection for HPV16 (OR = 1.36, 95%CI: 1.04-1.79) and HPV18 (OR = 2.31, 95%CI: 1.61-3.32), as well as for HPV52 and HPV58. Correlates of sexual exposure were associated with increased seroprevalence across most genotypes. Women who were current or former smokers were less likely to be seropositive for all eight of the tested oncogenic genotypes. The multiplex assay showed associations between seroprevalence and known risk factors for HPV infection across nearly all tested HPV genotypes but associations between DNA- and serostatus were weak, suggesting possible misclassification of the participants' HPV serostatus.

Comparison of immunosuppressive and immunomodulatory cells in keratoacanthoma and cutaneous squamous cell carcinoma.

An imbalance of immunosuppressive and immunomodulatory cells plays an important role in inhibiting the anti-tumour immune response in a tumour-bearing host. Among such cells, regulatory T cells (Tregs), together with immunosuppressive macrophages, such as CD163+ M2 macrophages, play roles in maintaining the tumour microenvironment. In contrast, interleukin-27 (IL-27) induces STAT1 and STAT3 activation, thus resulting in the enhancement of naive CD4 T-cell proliferation, the promotion of early Th1 differentiation, and the induction of the anti-tumour immune response. The purpose of this study was to investigate the involvement of immunosuppressive cells, such as Tregs and CD163+ macrophages, as well as immunomodulatory cells (i.e. IL-27-producing cells) in keratoacanthoma (KA) and invasive squamous cell carcinoma (SCC). We also examined the presence of CD3+ Foxp3+ Tregs cells in lesional skin from 10 patients with KA and 18 patients with SCC. Increased numbers of CD3+ Foxp3+ Tregs were observed in SCC compared with KA. In parallel with Tregs, higher numbers of CD163+ macrophages and MMP-9+ cells were detected only in SCC. In contrast, IL-27-producing cells were increased only in KA. In addition, the expression of pSTAT1 on tumour cells was observed only in KA. These findings suggest that the induction of immunosuppressive and immunomodulatory cells differs between KA and SCC.

Lack of regression of anal squamous intraepithelial lesions despite immune restoration under cART.

BACKGROUND: A high prevalence of anal squamous intraepithelial lesions (ASIL) and human papillomavirus (HPV) infections were observed in HIV-infected men who have sex with men (MSM) in the precART (combined antiretroviral therapy) era. The impact of cART on the natural history of HPV infection and ASIL is poorly documented. METHODS: Ninety-four HIV-infected MSM naive of cART were enrolled in a longitudinal study before starting cART. Patients were evaluated for anal cytology, histology and anal HPV DNA at baseline, month 12 and month 24 of cART. HPV DNA genotyping was performed by Linear Array assay. Anal cytologic samples were processed by the Thin Prep method. RESULTS: Analyses included 76 patients with at least two visits with available cytology. The median age was 39.4 years. The median (interquartile range) CD4 cell count was 301 cells/µl (242-339) at baseline and 545 cells/µl at month 24, when 93% of patients had plasma HIV-RNA 50 copies/ml or less. An abnormal result was observed in 45 of 76 patients at baseline (59%) with prevalent low-grade squamous intraepithelial lesion (LSIL) in 27 patients (36%) and high-grade squamous intraepithelial lesion (HSIL) in seven patients (9%) and in 36 of 69 patients assessed at month 24 (52%) with LSIL in 23 patients (33%) and HSIL in six patients (9%). At month 24, regression of the severity of lesions was observed in 44% of patients, whereas a lesion occurred in 37% of patients. CONCLUSION: Our results show a high prevalence and incidence of ASIL in HIV-infected MSM despite immune restoration under cART. These data emphasize that HIV-positive MSM although receiving effective cART remain at high risk of anal squamous intra-epithelial lesions.

Stem cells in squamous head and neck cancer.

The initiation and metastasis of head and neck squamous cell carcinomas (HNSCC) and other cancers have recently been related to the presence of cancer stem cells (CSC). CSC are cancer initiating, sustaining and are mostly quiescent. Specific markers that vary considerably depending on tumor type or tissue of origin characterize putative CSC. Compared to the bulk tumor mass, CSC are less sensitive to chemo- and radiotherapy and may also have low immunogenicity. Therapeutic targeting of CSC may improve clinical outcome of HNSCC which has two distinct etiologies: infection of epithelial stem cells by high-risk types of the human papillomavirus, or long-term tobacco and alcohol abuse. Recent knowledge on the role of CSC in HNSCC is reviewed and where necessary parallels to CSC of other origin are drawn to give a more comprehensive picture.

Tristetraprolin regulates interleukin-6, which is correlated with tumor progression in patients with head and neck squamous cell carcinoma.

BACKGROUND: Tumor-derived cytokines play a significant role in the progression of head and neck squamous cell carcinoma (HNSCC). Targeting proteins, such as tristetraprolin (TTP), that regulate multiple inflammatory cytokines may inhibit the progression of HNSCC. However, TTP's role in cancer is poorly understood. The goal of the current study was to determine whether TTP regulates inflammatory cytokines in patients with HNSCC. METHODS: TTP messenger RNA (mRNA) and protein expression were determined by quantitative real-time-polymerase chain reaction (Q-RT-PCR) and Western blot analysis, respectively. mRNA stability and cytokine secretion were evaluated by quantitative RT-PCR and enzyme-linked immunoadsorbent assay, respectively, after overexpression or knockdown of TTP in HNSCC. HNSCC tissue microarrays were immunostained for interleukin-6 (IL-6) and TTP. RESULTS: TTP expression in HNSCC cell lines was found to be inversely correlated with the secretion of IL-6, vascular endothelial growth factor (VEGF), and prostaglandin E2 (PGE(2) )(.) Knockdown of TTP increased mRNA stability and the secretion of cytokines. Conversely, overexpression of TTP in HNSCC cells led to decreased secretion of IL-6, VEGF, and PGE(2) . Immunohistochemical staining of tissue microarrays for IL-6 demonstrated that staining intensity is prognostic for poor disease-specific survival (P = .023), tumor recurrence and development of second primary tumors (P = .014), and poor overall survival (P = .019). CONCLUSIONS: The results of the current study demonstrated that down-regulation of TTP in HNSCC enhances mRNA stability and promotes secretion of IL-6, VEGF, and PGE(2) . Furthermore, high IL-6 secretion in HNSCC tissue is a biomarker for poor prognosis. In as much as enhanced cytokine secretion is associated with poor prognosis, TTP may be a therapeutic target to reduce multiple cytokines concurrently in patients with HNSCC.

Distinct epigenetic profiling in head and neck squamous cell carcinoma stem cells.

OBJECTIVE: To identify unique epigenetic signature in cancer stem cells (CSCs) in head and neck squamous cell carcinoma (HNSCC). STUDY DESIGN: Molecular and microarray studies. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Head and neck CSCs were isolated in HNSCC cells by CD44 staining and flow cytometry sorting. CSCs with highest CD44 expression (CD44(hi)) and non-stem cells (non-SCs) with lowest CD44 expression (CD44(low)) were then characterized for stemness gene expression and their responses to chemotherapeutic agents, followed by high-throughput epigenetic profiling using the Illumina BeadChip Array, targeting 28,544 CpG sites covering more than 14,956 genes. RESULTS: CD44(hi) CSCs expressed higher levels of stem cell markers and were more resistant to chemotherapeutic agents as compared to CD44(low) non-SCs. By DNA methylation microarray analysis, 17 hypomethylated and 9 hypermethylated genes were identified in CD44(hi) CSCs as compared to non-SCs in most HNSCC cell lines. Cluster analysis using these 26 genes showed that CD44(hi) CSCs were epigenetically distinct from the CD44(low) non-SCs in all 5 HNSCC cell lines. CONCLUSION: A unique epigenetic profile consisting of 17 hypomethylated and 9 hypermethylated genes was seen in HNSCC CSCs. These genes may be critically required in maintaining the stemness or pluripotency of CSCs and may represent novel molecular targets for anticancer therapies aimed at eradicating CSCs in HNSCC.

Interleukin-28B acts synergistically with cisplatin to suppress the growth of head and neck squamous cell carcinoma.

Interleukin-28B (IL-28B), also referred to as interferon-λ3, belongs to the type III interferon family. Earlier studies showed that IL-28B suppresses proliferation of some tumor cells in vitro. IL-28B gene transfection ex vivo also resulted in growth retardation of tumor cells in mice, through either direct antiproliferative action or induction of antitumor immunity. However, it has not been reported whether in vivo therapeutic administration of recombinant IL-28B can inhibit the growth of a pre-established tumor. Here, we found that repetitive subcutaneous administration of recombinant mouse IL-28B significantly induced tumor-specific cytotoxic T lymphocytes and augmented natural killer cytolytic activity, leading to moderate suppression of the growth of a murine head and neck squamous cell carcinoma (HNSCC) cell line that was completely resistant to the direct antiproliferative effect of IL-28B. Moreover, co-administration of recombinant mouse IL-28B and cisplatin (CDDP) more significantly inhibited in vivo growth of the tumor that had been established in syngenic mice and induced tumor-specific cytotoxic T lymphocytes. The CDDP treatment induced the expression of major histocompatibility complex class I and Fas molecules on the surface of HNSCC cells both in vitro and in vivo; this may be the mechanism underlying the synergistic tumor suppression activity of IL-28B and CDDP. Unlike type I interferon, IL-28B did not suppress growth of bone marrow cells in culture. Therefore, IL-28B may be useful as a tool for a novel multidisciplinary therapy against cancer, significantly potentiating innate and adaptive antitumor immune responses, especially when co-administrated with CDDP, which is currently the first choice chemotherapeutic agent against various tumors including HNSCCs.

Radioimmunotherapy of experimental head and neck squamous cell carcinoma (HNSCC) with E6-specific antibody using a novel HPV-16 positive HNSCC cell line.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide with a poor prognosis. Human papilloma virus (HPV) infection is associated with 20% HNSCC, and 50% of oropharyngeal carcinoma. HPV16 type is detected in 90% of all HPV+ HNSCC. Recently we suggested a fundamentally different approach to treatment of cancers of viral origin by targeting viral antigens on cancer cells with radiolabeled antibodies (mAbs) which promises exquisite specificity of treatment. We aimed at extending this approach to HPV-related head and neck cancer by performing radioimmunotherapy (RIT) targeting E6 and E7 oncogenes with radiolabeled mAbs. METHODS: We first aimed at developing HPV16+ cell line and animal model for RIT of HNSCC as at present there are no commercially available HPV16+ HNSCC cell lines and there is only one HPV+ cell line among the collection maintained by Dusseldorf, Michigan and Turku groups. Commercially available HNSCC cell line FaDu was transfected with pLXSN16E6E7 vector containing HPV16 E6 and E7 genes. Generated novel cell lines were evaluated by PCR and western blot and the tumorigenecity was assessed in nude mice. Proof of principle RIT targeting E6 oncoprotein in 2A3 tumor-bearing nude mice was conducted using unlabeled or 188-Rhenium (188Re)-labeled C1P5 mAb to E6. RESULTS: Novel HPV16+ 2A3 cell line reliably expressed E6 oncoprotein. E6 expression was modifiable with proteasome inhibitor MG132 in a dose-dependent manner. The levels of E6 expression in 2A3 cell line were estimated to be around 200 HPV copies per cell. The HPV16+ 2A3 cell line preserved 100% tumorigenicity of parent FaDu cells in nude mice. During RIT of 2A3 tumors in nude mice the relatively low dose of 200 µCi 188Re-C1P5 mAb was effective in decreasing the tumor growth in comparison with untreated controls. Unlabeled C1P5 mAb also caused some decrease in tumor progression, however, much less pronounced than 188Re-C1P5 mAb. CONCLUSIONS: We describe a proof-of-principle RIT study targeting HPV16 E6 oncoprotein with radiolabeled mAb to E6 in a stably transformed HPV16+ HNSCC cell line and tumor model in nude mice, and demonstrate potential utility of RIT as a novel molecular targeted therapy for HNSCC.

Deficiency of activated STAT1 in head and neck cancer cells mediates TAP1-dependent escape from cytotoxic T lymphocytes.

Squamous cell carcinoma of the head and neck (SCCHN) cells can escape recognition by tumor antigen (TA)-specific cytotoxic T lymphocytes (CTL) by downregulation of antigen processing machinery (APM) components, such as the transporter associated with antigen processing (TAP)-1/2 heterodimer. APM component upregulation by interferon gamma (IFN-γ) restores SCCHN cell recognition and susceptibility to lysis by CTL, but the mechanism underlying TAP1/2 downregulation in SCCHN cells is not known. Because IFN-γ activates signal transducer and activator of transcription (STAT)-1, we investigated phosphorylated (p)-STAT1 as a mediator of low basal TAP1/2 expression in SCCHN cells. SCCHN cells were found to express basal total STAT1 but low to undetectable levels of activated STAT1. The association of increased pSTAT1 levels and APM components likely reflects a cause-effect relationship, since STAT1 knockdown significantly reduced both IFN-γ-mediated APM component expression and TA-specific CTL recognition of IFN-γ-treated SCCHN cells. On the other hand, since oncogenic pSTAT3 is overexpressed in SCCHN cells and was found to heterodimerize with pSTAT1, we also tested whether pSTAT3 and pSTAT1:pSTAT3 heterodimers inhibited IFN-γ-induced STAT1 activation and APM component expression. First, STAT3 activation or depletion did not affect basal or IFN-γ-induced expression of pSTAT1 and APM components or recognition of SCCHN cells by TA-specific CTL. Second, pSTAT1:pSTAT3 heterodimers did not interfere with IFN-γ-induced STAT1 binding to the TAP1 promoter or APM protein expression. These findings demonstrate that APM component downregulation is regulated primarily by an IFN-γ-pSTAT1-mediated signaling pathway, independent of oncogenic STAT3 overexpression in SCCHN cells.