Nikolaos G. Nikitakis

High mobility group A2 is a target for miRNA-98 in head and neck squamous cell carcinoma

BackgroundHMGA2 expression has been shown to be associated with enhanced selective chemosensitivity towards the topoisomerase (topo) II inhibitor, doxorubicin, in cancer cells. Although the roles of signaling cascades and proteins as regulatory factors in development, neoplasia and adaptation to the environment are becoming well established, evidence for the involvement of regulatory small RNA molecules, such as microRNAs (miRNAs) as important regulators of both transcriptional and posttranscriptional gene silencing is presently mounting.ResultsHere we report that HMGA2 expression in head and neck squamous cell carcinoma (HNSCC) cells is regulated in part by miRNA-98 (miR-98). Albeit HMGA2 is associated with enhanced selective chemosensitivity towards topoisomerase (topo) II inhibitor, doxorubicin in HNSCC, the expression of HMGA2 is thwarted by hypoxia. This is accompanied by enhanced expression of miRNA-98 and other miRNAs, which predictably target HMGA2. Moreover, we show that transfection of pre-miR-98™ during normoxia diminishes HMGA2 and potentiates resistance to doxorubicin and cisplatin. These findings implicate the role of a miRNA as a key element in modulating tumors in variable microenvironments.ConclusionThese studies validate the observation that HMGA2 plays a prominent role in governing genotoxic responses. However, this may only represent cells growing under normal oxygen tensions. The demonstration that miRNA profiles are altered during hypoxia and repress a genotoxic response indicates that changes in microenvironment in eukaryotes mimic those of lower species and plants, where, for example, abiotic stresses regulate the expression of thousands of genes in plants at both transcriptional and posttranscriptional levels through a number of miRNAs and other small regulatory RNAs.

Immunohistochemical expression of cytokeratins 7 and 20 in malignant salivary gland tumors

On the basis of the heterogeneity of cytokeratins 7 and 20 expression in malignant epithelial tumors, the cytokeratin 7/20 immunophenotype has served as a useful diagnostic tool for discrimination of primary and/or metastatic carcinomas of unknown origin. However, the expression pattern of these cytokeratins in malignant salivary gland tumors has not been thoroughly studied. Our study material was composed of 84 malignant tumors of primary major or minor salivary gland origin. Nine histologic types of carcinoma were represented, including mucoepidermoid (26 cases), adenoid cystic (25), polymorphous low grade (11), salivary duct (8), acinic cell (4), ex mixed tumor (3), not otherwise specified (3), clear cell (2), and basal cell (2). In all, 13 cases of primary skin or mucosal squamous cell carcinoma with secondary salivary gland involvement were also examined. Immunoreactivity for cytokeratin 7 was evident in all malignant salivary gland tumors; the staining pattern was diffuse and strong in 62 cases, and focal and strong in 22 cases. In contrast, 78 cases were negative for cytokeratin 20, whereas only six cases (two mucoepidermoid, one adenoid cystic, and three salivary duct) displayed focal weak positivity. Overall, 92.9% of malignant salivary gland tumors were characterized by a cytokeratin 7 positive/20 negative immunoprofile, the remaining 7.1% of cases being positive for both cytokeratins. The latter phenotype was more common in salivary duct carcinomas (P≤0.05). On the other hand, most squamous cell carcinomas (69%) were negative for both cytokeratins, while the remaining cases (31%) were negative for cytokeratin 20 and focally weakly positive for cytokeratin 7. We suggest that assessment of cytokeratin 7/20 immunoprofile may facilitate the differential diagnosis of (a) primary malignant salivary gland tumors from metastatic tumors, (b) metastatic salivary gland tumors, (c) primary salivary gland tumors, especially mucoepidermoid carcinomas, from squamous cell carcinomas, and (d) salivary duct carcinomas from other malignant salivary gland tumors.

β-Tubulin-II Expression Strongly Predicts Outcome in Patients Receiving Induction Chemotherapy for Locally Advanced Squamous Carcinoma of the Head and Neck: A Companion Analysis of the TAX 324 Trial

PURPOSE TAX 324 was a phase III trial comparing induction chemotherapy (IC) with docetaxel, cisplatin, and fluorouracil (TPF) with cisplatin and fluorouracil (PF) followed by concomitant chemoradiotherapy in locally advanced squamous cell cancer of the head and neck (LASCCHN). This study evaluates a series of tumor markers in pretreatment biopsies from that trial TAX 324 and correlates expression with survival. METHODS Pretherapy biopsy specimens were available for 265 of 501 participants. Expression of a series of six markers (p53, thymidylate synthase, glutathione s-transferase pi [GST-pi], Bcl 2, beta tubulin II [betaT-2], and HER2 neu) was evaluated by immunohistochemistry. RESULTS For patients with low betaT-II expression, median overall survival (OS) was 58.6 months (95% CI, not reached [NR]), compared with 18.2 months for patients with high betaT-II expression (95% CI, 13.11 to 30.06: hazard ratio [HR], 2.39; 95% CI, 1.67 to 3.72; P < .0001). Progression-free survival in patients with low betaT-II expression was 43.2 months (95% CI, 24.4 to NR) versus 9.8 months (95% CI, 7.06 to 18.53) for high betaT-II expression, with a HR of 1.9 (95% CI, 1.43 to 2.77; P < .0001). The predictive value of betaT-II expression was greater in the TPF versus PF arm than in the PF arm. CONCLUSION Increased tumor expression of betaT-II is strongly associated with adverse outcome in LASCCHN patients treated with IC, and our data suggest low expression of betaT-II may predict patients most likely to benefit from induction TPF therapy. Further, simple models which combine expression of betaT-II with a carefully defined set of additional immunohistochemical markers may have significant prognostic impact for patients with LASCCHN.

Oral leiomyosarcoma: review of the literature and report of two cases with assessment of the prognostic and diagnostic significance of immunohistochemical and molecular markers

Leiomyosarcoma of the oral cavity is a very rare tumor that is associated with aggressive clinical behavior and low survival. In this paper, we report two new cases of leiomyosarcoma affecting the mandibular gingiva and mandible of a 35-year-old male and the mandible of a 51-year-old female. Given the difficulty in the histopathologic discrimination between benign and malignant smooth muscle tumors and the absence of reliable histologic parameters for prognostication of leiomyosarcomas, we evaluated the diagnostic and prognostic value of various immunohistochemical and molecular markers. By means of immunohistochemistry and quantitative real-time PCR analysis, we detected protein expression of PCNA, bcl-2, CDK4, p53 and MDM2 in both our cases and MDM2 amplification in our second case. The literature, pertinent to oral leiomyosarcoma and to molecular analysis of smooth muscle tumors, is reviewed.

PPARγ‐mediated antineoplastic effect of NSAID sulindac on human oral squamous carcinoma cells

There is strong evidence that nonsteroidal antiinflammatory drug (NSAID) sulindac may exert a significant antineoplastic effect. The purpose of our study was to explore the effects of sulindac on human oral squamous cell carcinoma (SCCa) cells and to elucidate the underlying molecular mechanisms. The changes that sulindac treatment induced on growth, apoptosis and cell cycle distribution of human oral SCCa cell lines were assessed by cell growth and flow cytometry experiments. Utilizing quantitative RT‐PCR and immunocytochemistry, we determined the effect of sulindac treatment on mRNA and protein expression of different sulindacs targets. Also, PPARγ expression was selectively targeted by antisense oligonucleotide treatment. Both sulfide and sulfone metabolites of sulindac, which differ in the ability to cause COX‐2 inhibition, induced a significant dose‐ and time‐dependent cell growth reduction accompanied by increase in apoptosis without concomitant cell cycle arrest. Sulindac treatment also caused upregulation of the protein and mRNA expression levels of COX‐2 and PPARs. Treatment with antisense PPARγ oligonucleotides abolished sulindacs growth inhibitory effect. Our results are consistent with a significant growth inhibitory effect of NSAID sulindac on human oral SCCa cells, which is mediated, at least partially, through induction of apoptosis. We suggest that upregulation of PPARγ expression and activation may be, at least partially, responsible for sulindacs antiproliferative effect.

Primary Sjögren syndrome in childhood: report of a case and review of the literature.

Sjögren syndrome (SS) in childhood is a rare and possibly underdiagnosed condition. The purpose of this study is to report a case of primary SS (PSS) in a 4-year-old Venezuelan girl and to review the pertinent literature. The patient presented with bilateral recurrent parotid enlargement, predominantly on the right side. She did not complain of dry mouth or eyes; however, decreased stimulated salivary flow rate and positive Schirmer and rose bengal tests were obtained. Sialography, sonograms, and a computed tomography scan of the parotid glands revealed pathologic changes consistent with SS. Anti-SS-A and anti-SS-B antibodies were present. Evaluation for antibodies against cytomegalovirus, Epstein-Barr virus, and HIV rendered negative results. Histopathologic examination of incisional biopsies of the right parotid and labial minor salivary glands revealed focal periductal lymphocytic infiltrate and sialoduct ectasia. Taken together, these findings are consistent with the diagnosis of juvenile PSS. The salient features of this rare disease are summarized on the basis of a comprehensive review of the epidemiologic, clinical, and serologic findings of the previously reported cases of PSS in children.

Water-soluble polymers for targeted drug delivery to human squamous carcinoma of head and neck

Human squamous cell carcinoma of the head and neck (SCCHN) is characterized by over expression of a tumor cell surface-specific receptor namely Hsp47/CBP2 that makes it a favorable candidate for targeted delivery of anticancer drugs. Several synthetic peptides have been identified as effective ligands for binding to CBP2. The purpose of this study is to investigate the potential of water-soluble N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-doxorubicin (Dox) conjugates containing a Hsp47/CBP2 binding peptide sequence, namely WHYPWFQNWAMA for targeted delivery to SCCHN. An HPMA copolymer containing Dox and CBP2 targeting peptide conjugated via lysosomally degradable glycylphenylalanylleucylglycine (GFLG) spacer was synthesized by free radical precipitation copolymerization. A control polymer without targeting moiety was also synthesized. The conjugates were characterized for drug content, peptide content, molecular weight and molecular weight distribution. The uptake of polymeric conjugates by both drug resistant and drug sensitive SCCHN cells were determined in vitro by flow cytometry using FACS scan analysis. Cytotoxicity of the conjugates towards drug sensitive as well as multidrug resistant SCCHN cells were evaluated by a clonal survival assay and compared to free Dox. The cytotoxicity of the free peptide was similarly evaluated. The internalization and subcellular fate of the conjugates in drug sensitive SCCHN cells was monitored using confocal microscopy. The new targetable copolymer contained 0.16 mmole peptide/g polymer. Studies on drug sensitive SCCHN cells demonstrated lesser uptake of both targeted and non-targeted conjugates compared to free Dox suggesting a slower endocytic mechanism of uptake for the conjugates as opposed to rapid diffusion of free Dox. At higher Dox equivalent concentrations (>20 μM) the targeted conjugate showed significantly higher uptake (p≤0.028) than the non-targeted conjugate. The uptake of the targeted conjugate was inhibited in the presence of an anti Hsp47 antibody suggesting the involvement of active receptor mediated endocytosis in cell entry of the conjugate. Compared to free Dox, the targeted and non-targeted conjugates caused marginally lower inhibition (p≤0.01) of the drug sensitive SCCHN cells. In contrast, the same conjugates showed significantly higher uptake (p≤0.004) by drug resistant SCCHN cells and caused significantly higher inhibition (p≤0.02) of drug resistant SCCHN cells when compared to free Dox. Results suggest that the polymeric conjugates were able to overcome drug resistance. Confocal microscopy studies demonstrated the uptake of the polymeric conjugates, followed by internalization, intralysosomal localization and subsequent release of Dox. HPMA copolymer-Dox-peptide conjugates targeted to SCCHN cells were able to overcome drug resistance and increase efficacy in vitro. The results suggest that targetable polymeric conjugates have potential to improve systemic head and neck cancer chemotherapy by increasing tumor localization and reducing dose-limiting toxicity.

Immunohistochemical evaluation of cell proliferation antigen Ki-67 and apoptosis-related proteins Bcl-2 and caspase-3 in oral granular cell tumor

PURPOSE We sought to evaluate the cell proliferation activity and immunohistochemical expression of proteins that promote or inhibit apoptosis in oral granular cell tumor (GCT). STUDY DESIGN Immunohistochemistry for Ki-67, a cell proliferation marker; Bcl-2, an anti-apoptotic protein; and caspase-3, a protein implicated in the execution of apoptosis, was performed on tissues from 12 patients with GCT of the tongue. RESULTS Nuclear immunostaining for Ki-67 was observed only in isolated GCs (less than 2%). All patients exhibited cytoplasmic immunoreactivity for Bcl-2 in the majority of tumor cells. Cytoplasmic staining for caspase-3 was also present in more than 50% of GCs in all tumors. CONCLUSIONS GCT cells display low proliferation activity, a finding possibly related to their benign behavior. Caspase-3 expression suggests activation of the apoptotic cascade in the GCs, but persistence of the cells in the tissues could be attributed to the expression of Bcl-2 protein, a molecule that functions as a survival factor.

Malignant peripheral primitive neuroectodermal tumor‐peripheral neuroepithelioma of the head and neck: A clinicopathologic study of five cases and review of the literature

The term primitive neuroectodermal tumor (PNET) encompasses a number of neoplasms of common neuroectodermal origin, but of variable clinical, histopathologic, ultrastructural, and molecular characteristics. Here, we focus on one particular member of the PNET family, the malignant peripheral PNET (pPNET) or peripheral neuroepithelioma of head and neck.

Granulomatous Foreign-Body Reaction Involving Oral and Perioral Tissues After Injection of Biomaterials: A Series of 7 Cases and Review of the Literature

PURPOSE Injectable implants used for soft-tissue augmentation may lead to a granulomatous foreign-body reaction. The aim of this report is to present 7 new cases of foreign-body granulomas involving the oral and perioral tissues, after injection of biomaterials to achieve soft-tissue augmentation. In addition, the clinical and epidemiological profile of this condition is summarized, based on a review of the English-language literature of all previously described cases. PATIENTS AND METHODS We report on 7 new cases of granulomatous foreign-body reaction involving the oral and perioral tissues after the injection of biomaterials. A comprehensive literature review is also presented. RESULTS The literature search revealed 49 cases of this condition affecting the oral and perioral tissues. Our 7 patients were female, with a mean age of 52.8 years (range, 34 to 70 years). The lower lip was affected in 4 cases, 1 case was located in the upper lip, 1 case in the buccal mucosa, while 1 case involved 2 different sites (upper lip and buccal mucosa). Histopathologic examination revealed numerous cells with clear, often multiple, cytoplasmic vacuoles, bearing a resemblance to lipoblasts. Immunohistochemistry revealed diffuse positivity for the histiocytic marker CD68. CONCLUSIONS The diagnosis of granulomatous foreign-body reactions may be challenging because of their microscopic resemblance to liposarcoma, and because of the occasional reluctance of patients to report the previously performed esthetic procedure. A clinical history, histopathologic examination, and immunohistochemical analysis (as needed) are essential in achieving an accurate diagnosis.