Changing expression of E- and P-cadherin during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide

Designing a Mucoadhesive ChemoPatch to Ablate Oral Dysplasia for Cancer Prevention

Oral cancer has a high mortality rate, and its treatment often causes debilitating complications. More than 90% of oral cancers are oral squamous cell carcinomas (OSCCs) that may develop from clinically recognizable oral premalignant lesions (OPLs). To eradicate OPLs before they turn into cancers, a non-invasive topical formulation is developed based on a novel combination of synergistically acting oxaliplatin (OXP) and mycophenolate (MPS) embedded in a controlled-release mucoadhesive patch fabricated by computer-aided 3D printing. After multiple rounds of testing and optimization, a v6.4 ChemoPatch is designed, which shows sustained release of OXP and MPS in vitro, minimal side leakage of drugs, an average elastic modulus of 2.38 MPa, and suitable drug stability at 4 °C or below for up to 12 months. In vivo analyses show almost all patches adhere to the dorsal tongue surface for 4 hours, and display a sustained release of OXP and MPS to tongue tissue for 3-4 hours. When applied in the 4-nitroquinoline-1-oxide-induced OPL rat model, the OXP-MPS patch significantly ablates dysplastic lesions with no damage to normal epithelial cells and minimal systemic absorption and side effects. This study reports the design of a novel mucoadhesive ChemoPatch as a noninvasive therapy to treat OPLs.

Evaluation of immunohistochemical expression of E-cadherin in pleomorphic adenoma and adenoid cystic carcinoma

Background:

Pleomorphic adenoma (PA) and adenoid cystic carcinoma (ADCC) are benign and malignant salivary gland tumors, respectively, with distinct behavior. They have similar origins and cell components. E-cadherins are the main homophilic cell adhesion molecules, which play a central role in maintaining epithelial integrity, functioning in intercellular adhesion and differentiation. Hence, changes in E-cadherin function are reflected in the morphologic events associated with the cellular arrangement, movement and wound healing.

Aim:

To study and compare the expression of E-cadherin immunostaining in PA and ADCC.

Materials and Methods:

Fifteen cases of each PA and ADCC were immunohistochemically stained with E-cadherin. Five cases of normal salivary gland tissues were taken as the positive control.

Mann–Whitney U-test was used for statistical analysis.

Results:

About 86.6% of PA cases showed homogeneous staining. 66.6% of cases of ADCC showed heterogeneous staining. PA, cribriform and tubular patterns of ADCC predominantly showed moderate immune-staining and solid patterns of ADCC exhibited predominantly mild immunostaining. Depending on the intensity of staining, we found a significant P value between PA and the solid variant of ADCC.

Conclusion:

E-cadherin proved to be a better marker for epithelial phenotypes in PAs. In ADCC difference in staining intensity between different histological subtypes suggests that further studies should be done to assess the usefulness of an immuno-marker to know the aggressive behavior of ADCC.

Immune-relevant aspects of murine models of head and neck cancer

Head and neck cancers (HNCs) cause significant mortality and morbidity. There have been few advances in therapeutic management of HNC in the past 4 to 5 decades, which support the need for studies focusing on HNC biology. In recent years, increased recognition of the relevance of the host response in cancer progression has led to novel therapeutic strategies and putative biomarkers of tumor aggressiveness. However, tumor-immune interactions are highly complex and vary with cancer type. Pre-clinical, in vivo models represent an important and necessary step in understanding biological processes involved in development, progression and treatment of HNC. Rodents (mice, rats, hamsters) are the most frequently used animal models in HNC research. The relevance and utility of information generated by studies in murine models is unquestionable, but it is also limited in application to tumor-immune interactions. In this review, we present information regarding the immune-specific characteristics of the murine models most commonly used in HNC research, including immunocompromised and immunocompetent animals. The particular characteristics of xenograft, chemically induced, syngeneic, transgenic, and humanized models are discussed in order to provide context and insight for researchers interested in the in vivo study of tumor-immune interactions in HNC.

Patients with advanced oral squamous cell carcinoma have high levels of soluble E-cadherin in the saliva

BACKGROUND

The objective of this study was to assess the potential clinical value of the concentration of soluble salivary E-cadherin (sE-cadherin) compared with the clinical value of the presence of membranous E-cadherin (mE-cadherin) in oral squamous cell carcinoma tumor tissues.

MATERIAL AND METHODS

Data regarding patient demographics, clinical stage, saliva and tumor tissue samples were collected. The saliva was analyzed for sE-cadherin protein levels and was compared to the mE-cadherin immunohistochemical expression levels in tumor tissues, which were assessed via the HercepTest® method. Patients without cancer were included in the study as a control group for comparisons of the sE-cadherin levels.

RESULTS

sE-cadherin levels in the saliva of patients without cancer were lower than those in patients with cancer, and the difference was statistically significant (p=0.031). Low mE-cadherin expression was statistically significantly associated with lymph node positivity (p=0.015) and advanced clinical stage (p=0.001). The inverse relationship between mE-cadherin and sE-cadherin was significant in terms of lymph node positivity (p=0.014) and advanced clinical stage (p=0.037).

CONCLUSIONS

The results suggest that sE-cadherin levels are significantly increased in patients with oral cancer and that its low expression within the membrane as well as the progression of the disease appear to be inversely associated with levels of sE-cadherin in the saliva.

Pathophysiology of oral cancer in experimental animal models: a review with focus on the role of sympathetic nerves

Global increase in incidence and mortality as well as poor prognosis of oral cancer (OC) has intensified efforts towards early detection and prevention of this disfiguring disease. Several studies have been conducted using experimental animal models to understand the pathophysiology and molecular events involved in OC. Lack of identification of specific biomarkers during the multifaceted steps of oral carcinogenesis has hindered its diagnosis and treatment. Solid stress generated by growing tumors as well as abnormalities in tumor vasculature lead to increased interstitial fluid pressure, which could obstruct therapeutic drug delivery to tumors. Furthermore, the sympathetic nervous system is known to affect angiogenesis, vessel permeability, immune responses and carcinogenesis. Recent findings indicate that, in addition to angiogenic and lymphangiogenic factors, tumor cells release neurotrophic factors that initiate innervation. Interactions between cytokines and sympathetic neurotransmitters, and their respective receptors expressed by the nerve, immune and tumor cells appear to influence tumor growth. Thus, understanding the complex signaling processes and interrelationships between vascular, nervous and immune systems during oral carcinogenesis may prove vital for successful prevention and treatment of OC. This review aims at outlining the available knowledge on pathophysiology of OC in experimental animal models including evidence from our own findings.

Distribution and quantity of label-retaining cells in rat oral epithelia

BACKGROUND

Label-retaining cells (LRCs), the presumptive stem cells, have been detected in the mouse and hamster oral epithelia, but the data on LRCs in rat oral epithelia have not been available yet. The aim of this study was to identify LRCs in oral squamous epithelia of rat.

METHODS

Fifty-four two-week-old Sprague-Dawley rats were injected intraperitoneally with BrdU twice daily for four consecutive days. The BrdU-labeled rats were sacrificed at 2 h, week 2, 4, 6, 8, 10, 12, 14 and 16 after the last BrdU injection. The tissues of cheek, tongue and palate were analyzed by techniques of fluorescence-activated cell sorting (FACS) and immunohistochemistry.

RESULTS

The number of BrdU-labeled cells quantified by FACS increased within 2 weeks after labeling, then, decreased gradually until week 10. After week 10, the BrdU-labeled cells were found to locate mainly in basal layer and their number kept consistent at 3-7% of total oral epithelial cells. The number of BrdU-labeled epithelial cells in palate was statistically higher than that in cheek or tongue at the same time point.

CONCLUSIONS

This study showed that the number and the distribution of BrdU-labeled epithelial cells stabilized from 10 weeks after labeling. Therefore, these BrdU-labeled cells after a 10-week chase were considered oral epithelial LRCs.

Animal models of cancer in the head and neck region

Animal models that resemble the cancers of the head and neck region are of paramount importance in studying the carcinogenesis of these diseases. Although several methods for modeling cancer in the head and neck are available, none are fully satisfactory. Subcutaneous xenograft models of cancer in nude mice are often used in preclinical studies. However, these models are problematic in several aspects as they lack the specific interactions that exist between the tumor cells and their native environment. Establishment of tumors at the orthotopic sites restore these distinct patterns of interactions between the tumor and the host organs that are lost or altered when the tumors are established in ectopic sites. With regard to the transgenic model of cancer in the head and neck region, it should be kept in mind that the transgene used to drive the malignant transformation may not be representative of the carcinogenic process found in human tumors. Low penetrance of tumor formation also translates into high cost and time commitment in performing studies with transgenic models. In this review, we will discuss some of the commonly used methods for modeling cancer in the head and neck region including squamous cell carcinoma of the head and neck as well as thyroid carcinoma.

Molecular mechanisms of head and neck cancer

Despite advances in understanding the underlying genetics, squamous cell carcinoma of the head and neck (SCCHN) remains a major health risk and one of the leading causes of mortality in the world. Current standards of treatment have significantly improved long-term survival rates of patients, but second tumors and metastases still remain the most frequent cause of high mortality in SCCHN patients. A better understanding of the underlying genetic mechanisms of SCCHN tumorigenesis will help in developing better diagnostics and, hence, better cures. In this article we will briefly outline the current state of diagnostics and treatment and our understanding of the molecular causes of SCCHN.

Epithelial to mesenchymal transition in head and neck squamous carcinoma: association of Src activation with E-cadherin down-regulation, vimentin expression, and aggressive tumor features

BACKGROUND

Epithelial-mesenchymal transformations (EMT) are critical for the invasion, progression, and metastasis of epithelial carcinogenesis. The role of EMT in head and neck squamous carcinoma (HNSC) tumorigenesis remains unexplored. In the current study, the expressions of several factors associated with the induction of EMT in HNSC cell lines and tumor specimens were investigated to define their functional and pathologic role in HNSC.

METHODS

Eleven HNSC cell lines and 50 primary tumor tissue specimens formed the materials of this study. Western blot analysis as well as immunohistochemical, and functional techniques were used to assess the status of activated Src (p-Src), E-cadherin, and vimentin in both cell lines and tumor tissues and the results were correlated with patients' clinicopathologic parameters.

RESULTS

The results demonstrated the inverse expression of p-Src and E-cadherin in the majority of cell lines and in primary tumor tissues compared with normal squamous mucosa. Elevated levels of p-Src were accompanied by down-regulation of E-cadherin and the expression of vimentin in epithelial tumor cells. In vitro inhibition of Src led to E-cadherin reexpression and increased cell contact in squamous carcinoma cell lines. Immunophenotypic analysis of these markers in primary tumor tissues demonstrated a significant correlation between increased p-Src, decreased E-cadherin, and vimentin expression and aggressive tumor features including penetrating invasive fronts, high-grade sarcomatoid transformation, and lymph node metastasis.

CONCLUSIONS

The results of the current study indicate that Src and E-cadherin may play an important role in EMT, invasion, and aggressive clinicopathologic features of HNSC. These proteins may be targeted for the therapeutic intervention of patients with HNSC.

4-nitroquinoline-1-oxide induced experimental oral carcinogenesis

Human oral cancer is the sixth largest group of malignancies worldwide and single largest group of malignancies in the Indian subcontinent. Seventy percent of premalignant cancers appear from premalignant lesions. Only 8-10% of these lesions finally turn into malignancy. The appearance of these premalignant lesions is one distinct feature of human oral cancer. At present there is dearth of biomarkers to identify which of these lesions will turn into malignancy. Regional lymph node metastasis and locoregional recurrence are the major factors responsible for the limited survival of patients with oral cancer. Paucity of early diagnostic and prognostic markers is one of the contributory factors for higher mortality rates. Cancer is a multistep process and because of constrain in availability of human tissues from multiple stages of oral carcinogenesis including normal tissues, animal models are being widely used, aiming for the development of diagnostic and prognostic markers. A number of chemical carcinogens like coal tar, 20 methyl cholanthrene (20MC), 9,10-dimethyl-1,2-benzanthracene (DMBA) and 4-nitroquinoline-1-oxide (4NQO) have been used in experimental oral carcinogenesis. However, 4NQO is the preferred carcinogen apart from DMBA in the development of experimental oral carcinogenesis. 4NQO is a water soluble carcinogen, which induces tumors predominantly in the oral cavity. It produces all the stages of oral carcinogenesis and several lines of evidences suggest that similar histological as well as molecular changes are observed in the human system. In the present review an attempt has been made to collate the information available on mechanisms of action of 4NQO, studies carried out for the development of biomarkers and chemopreventives agents using 4NQO animal models.

Animal models in oral cancer research

Biologically and clinically relevant animal models are essential in investigation of the progression of diseases and the elaboration of diagnostic or therapeutic protocols. The several rodent models used for in vivo evaluation for oral cancer employ chemical, transplantation and genetic (knockout and transgenic) induction methods. These models are described together with their advantages and disadvantages. Their optimization and application in future research may improve the early detection and treatment of oral cancer.

Reduced E-cadherin expression is an indicator of unfavourable prognosis in oral squamous cell carcinoma

The aim was to evaluate E-cadherin expression in oral squamous cell carcinoma, and its possible relationships with tumour histology and with clinical course and survival. Surgical biopsies from 47 cases of oral squamous cell carcinoma were analysed for expression of E-cadherin using immunohistochemistry. Statistical analyses were performed to identify possible associations with tumour clinic-histological features and with clinical course and survival. Weak or absent E-cadherin expression was associated with a more invasive histological pattern and with metastasis to the cervical lymph nodes. Uni- and multivariate analyses indicated that weak or undetectable E-cadherin expression is an indicator of shorter disease-free period and shorter survival time. Reduced E-cadherin expression in oral squamous cell carcinoma is associated with more aggressive tumour behaviour and worse prognosis.

Identification of P-cadherin in Primary Melanoma Using a Tissue Microarrayer

Sentinel lymph node biopsy is the most accurate technique for establishing melanoma patient prognosis but is associated with morbidity and is of little value in those tumors that first metastasize to sites other than the regional nodal basin. Noninvasive methods of establishing prognosis are therefore desirable. We have used the novel technology of tissue microarray to study a cohort of 120 patients with melanoma with long-term follow-up data for the expression of P-cadherin. The tissue microarray was successfully constructed and stained. Loss of P-cadherin expression was found to be significantly correlated with outcome (log rank chi2 = 10.1336, P = 0.0015). The results suggest a fundamental role for P-cadherin in melanoma progression and identify it as a potential prognostic marker and a possible target for therapeutic manipulation.

P-cadherin expression and survival rate in oral squamous cell carcinoma: an immunohistochemical study

BACKGROUND

P-cadherin (P-cad) is a transmembrane molecule involved in the cell-cell adhesion and similar to E-cadherin (E-cad), but less investigated in oncology, especially in in vivo studies. Aims of the present study were to assess the prevalence of P-cad expression in oral squamous cell carcinoma (OSCC) and to verify whether P-cad can be considered a marker of prognosis in patients with OSCC.

METHODS

In a retrospective study, a cohort of 67 OSCC patients was investigated for P-cad expression and its cellular localization by immunohistochemistry; some respective healthy margins of resection were similarly investigated as standard controls. After grouping for P-cad expression, OSCCs were statistically analyzed for the variables age, gender, histological grading (G), TNM, Staging, and overall survival rate. Univariate and multivariate analyses were performed.

RESULTS

37 cases (55.2%) of OSCC showed membranous/cytoplasmic positivity for P-cad, whereas 30 (44.8 %) were negative. Although with some differences in membranous vs cytoplasmic localization of P-cad in OSCC with different G, no statistical association was found between P-cad expression and any variables considered at baseline. In terms of prognostic significance, P-cad non expression was found to have an independent association with poorer overall survival rate than P-cad expressing group (P = 0.056); moreover, among P-cad +ve patients the best prognosis was for those OSCC with membranous (P < 0.0001) than those with cytoplasmic P-cad expression.

CONCLUSION

On the basis of these results, it is possible to suggest P-cad as an early marker of poor prognosis. The abnormal or lack of P-cad expression could constitute an hallmark of aggressive biological behavior in OSCC.