An immunohistochemical study of basement membrane heparan sulfate proteoglycan (perlecan) in oral epithelial dysplasia and squamous cell carcinoma

Hypoxia-Induced Biosynthesis of the Extracellular Matrix Molecules, Perlecan and Fibronectin, Promotes the Growth of Pleomorphic Adenoma Cells In Vitro Models

Salivary pleomorphic adenoma is histopathologically characterized by its colorful stroma with myxoid, chondroid, and hyaline appearances, due to enhanced biosynthesis of extracellular matrix (ECM) molecules and poor vascularity. Thus, pleomorphic adenoma cells embedded in the stroma typically survive under hypoxic conditions. We determined the expression kinetics of ECM molecules, such as perlecan and fibronectin (FN), under hypoxia in SM-AP1 cells which are duct epithelial differentiated cells, and in SM-AP4 cells, which are myoepithelial differentiated cells, cloned from pleomorphic adenoma of the parotid gland. We investigated hypoxia-inducible factor-1α (HIF-1α)-inducing pathways through a variety of ECM molecules in association with their cellular proliferation and migration. We observed that hypoxic conditions with elevated HIF-1α protein levels induced increased expression of perlecan and FN in SM-AP cells than in controls. Moreover, perlecan and FN knockdown reduced the proliferation of SM-AP1 and SM-AP4 cells under hypoxia. Further, SM-AP1 cell migration was enhanced by both perlecan and FN knockdown, whereas SM-AP4 cell migration was increased by perlecan knockdown and inhibited by fibronectin knockdown. The results indicated that pleomorphic adenoma cells can survive under hypoxic conditions by promoting cell proliferation via enhanced synthesis of ECM molecules. Overall, ECM molecules may be a new anti-tumor target under hypoxic conditions.

Precancerous Lesions of the Head and Neck Region and Their Stromal Aberrations: Piecemeal Data

Head and neck squamous cell carcinomas (HNSCCs) develop through a series of precancerous stages from a pool of potentially malignant disorders (PMDs). Although we understand the genetic changes that lead to HNSCC, our understanding of the role of the stroma in the progression from precancer to cancer is limited. The stroma is the primary battleground between the forces that prevent and promote cancer growth. Targeting the stroma has yielded promising cancer therapies. However, the stroma at the precancerous stage of HNSCCs is poorly defined, and we may miss opportunities for chemopreventive interventions. PMDs already exhibit many features of the HNSCC stroma, such as inflammation, neovascularization, and immune suppression. Still, they do not induce cancer-associated fibroblasts or destroy the basal lamina, the stroma's initial structure. Our review aims to summarize the current understanding of the transition from precancer to cancer stroma and how this knowledge can reveal opportunities and limitations for diagnostic, prognostic, and therapeutic decisions to benefit patients. We will discuss what may be needed to fulfill the promise of the precancerous stroma as a target to prevent progression to cancer.

Bioinformatic Analysis of Plus Gene Expression Related to Progression from Leukoplakia to Oral Squamous Cell Carcinoma

INTRODUCTION

Leukoplakia is one of the most frequently found lesions in the oral cavity, with a probability of 17 to 24% of becoming malignant cells in a period of 30 years.

OBJECTIVE

To identify differentially expressed gene profiles of leukoplakia and its progression to oral squamous cell carcinoma, essential for the discovery of new biomarkers to predict and prevent the presence of diseases in the oral cavity.

METHODS

Initially, gene profiles of GSE85514 and GSE160042 from the Gene Expression Omnibus database were used. Differentially expressed genes were identified using GEO2R. The CLUEGO plugin in Cytoscape was used for DEG functionality and enrichment analysis. Finally, a protein-protein interaction (PPI) network was constructed using Cytoscape from data collected online from the STRING server.

RESULTS

According to the MCC algorithm, the 10 most found gene sequences were HNRNPU, SMC1A, PAFAH1B1, EHMT1, SPTBN4, OLFM1, NCAM1, SF3B3, FGF2, and UBE2I; with HNRNPU, SMC1A, and PAFAH1B1 being the most representative of the modules.

CONCLUSIONS

We were able to describe the gene sequences that promote the progression from leukoplakia to oral squamous cell carcinoma. Within these genes, the HNRNPU, SMC1A, and PAFAH1B1 constitute the main promising therapeutic targets to counteract the progression of oral cancer, they could also be important biomarkers for the diagnosis and classification of the disease.

Histopathologic and immunohistochemical findings of odontogenic jaw cysts treated by decompression technique

Context

Odontogenic cysts are among the most common lesions to affect the oral and maxillofacial region. Cysts are capable of causing significant bony disfigurement, tooth displacement and pathological fractures. Several surgical approaches exist for the management of larger cysts of the jaws. These include enucleation, marsupialization and decompression.

Aims

1. Analysis of histopathologic findings in odontogenic cysts before and after decompression2. Analysis of Ki-67 expression in odontogenic jaw cysts before and after decompression.

Settings and Design

Decompression technique was used for the treatment of 10 cases of odontogenic cysts in the study. Incisional biopsies of cystic lining (pretreatment) and corresponding excisional biopsies (posttreatment) were received for histopathologic and immunohistochemical examination.

Subjects and Methods

Hematoxylin and eosin stain was used for histopathologic findings, and Ki-67 was used for immunohistochemical findings using antibody Ki-67 in fresh tissue samples.

Results

Overall, radicular cysts, dentigerous cysts, and sialo-odontogenic cyst contained fewer Ki-67 ⁺ cells than odontogenic keratocysts. The average scores were found to be 2.2 and 1 for before and after decompression, respectively. A statistically significant difference was observed between the two groups. The two-tailed P value was found to be <0.0001. The confidence interval was found to be 95%.

Conclusions

The proliferative activity evaluated by Ki-67 marker was greater in predecompression epithelial lining compared to postdecompression. Our study infers that proliferative rate of the cystic epithelial lining is significantly diminished after decompression.

Perlecan, a modular instructive proteoglycan with diverse functional properties

This study reviewed some new aspects of the modular proteoglycan perlecan, a colossal proteoglycan with a 467 kDa core protein and five distinct functional domains. Perlecan is a heparan sulphate proteoglycan that transiently displays native CS sulphation motifs 4-C-3 and 7-D-4 during tissue morphogenesis these are expressed by progenitor cell populations during tissue development. Perlecan is susceptible to fragmentation by proteases during tissue development and in pathological tissues particularly in domains IV and V. The fragmentation pattern of domain IV has been suggested as a means of grading prostate cancer. Domain V of perlecan is of interest due to its interactive properties with integrin α5β1 that promotes pericyte migration enhancing PDGF-BB-induced phosphorylation of PDGFRβ, Src homology region 2 domain-containing phosphatase-2, and focal adhesion kinase supporting the repair of the blood brain barrier following ischaemic stroke. Fragments of domain V can also interact with α2β1 integrin disrupting tube formation by endothelial cells. LG1-LG2, LG3 fragments can antagonise VEGFR2, and α2β1 integrin interactions preventing angiogenesis by endothelial cells. These domain V fragments are of interest as potential anti-tumour agents. Perlecan attached to the luminal surfaces of endothelial cells in blood vessels acts as a flow sensor that signals back to endothelial and smooth muscle cells to regulate vascular tone and blood pressure. Perlecan also acts as a flow sensor in the lacuno-canalicular space regulating osteocytes and bone homeostasis. Along with its biomechanical regulatory properties in cartilaginous tissues this further extends the functional repertoire of this amazingly diverse functional proteoglycan.

Expression and Circulating Levels of Perlecan in Breast Cancer - Implications for Oestrogen Dependent Stromal Remodeling

Localised breast cancer can be cured by surgery and adjuvant treatments, but mortality remains high as some tumours metastasize early. Perlecan is a basement membrane (BM) protein involved in tumour development and progression. Here, mRNA and protein expression of perlecan, and mRNA expression of matrix degrading enzymes were studied in normal breast and invasive breast cancer, and correlated to prognostic risk factors, in particular oestrogen status. Moreover, plasma levels of perlecan were measured in patients with breast cancer and compared with controls. mRNA data was extracted from the Cancer Genome Atlas database. Perlecan protein expression was visualized using immunofluorescence and plasma levels measured by ELISA assay. Perlecan mRNA levels were twice as high in normal breast compared with breast cancer tissue. A strong correlation was found between mRNA expression of perlecan and several matrix-degrading enzymes in oestrogen receptor positive (ER+) tumours. Perlecan protein was localized to both epithelial and vascular BMs, but absent in the stroma in normal breast. In breast cancer, the expression of perlecan in epithelial BM was fragmented or completely lost, with a marked upregulation of perlecan expression in the stroma. Significantly higher levels of perlecan were found in plasma of ER+ patients when compared with ER- patients. This study shows that perlecan expression and degradation in breast cancer may be linked to the ER status of the tumour.

Proteoglycans remodeling in cancer: Underlying molecular mechanisms

Extracellular matrix is a highly dynamic macromolecular network. Proteoglycans are major components of extracellular matrix playing key roles in its structural organization and cell signaling contributing to the control of numerous normal and pathological processes. As multifunctional molecules, proteoglycans participate in various cell functions during morphogenesis, wound healing, inflammation and tumorigenesis. Their interactions with matrix effectors, cell surface receptors and enzymes enable them with unique properties. In malignancy, extensive remodeling of tumor stroma is associated with marked alterations in proteoglycans' expression and structural variability. Proteoglycans exert diverse functions in tumor stroma in a cell-specific and context-specific manner and they mainly contribute to the formation of a permissive provisional matrix for tumor growth affecting tissue organization, cell-cell and cell-matrix interactions and tumor cell signaling. Proteoglycans also modulate cancer cell phenotype and properties, the development of drug resistance and tumor stroma angiogenesis. This review summarizes the proteoglycans remodeling and their novel biological roles in malignancies with particular emphasis to the underlying molecular mechanisms.

Extracellular matrix as target for antitumor therapy

The aim of the present review is to survey the accumulated knowledge on the extracellular matrix (ECM) of tumors referring to its putative utility as therapeutic target. Following the traditional observation on the extensive morphological alteration in the tumor-affected tissue, the well-documented aberrant cellular regulation indicated that ECM components have an active role in tumor progression. However, due to the diverse functions and variable expression of proteoglycans, matrix proteins, and integrins, it is rather difficult to identify a comprehensive therapeutic target among ECM components. At present, the elevated level of heparanase and the prominent expression of αvβ5 integrin are considered as promising therapeutic targets. The inhibition of glycosaminoglycan offers another promising approach in the treatment of those tumors which are stimulated by proteoglycans. It can be ascertained that a selective ECM inhibitor would be a great asset to control metastasis driven by ECM-mediated signaling.

Tumor stroma and chemokines control T-cell migration into melanoma following Temozolomide treatment

The infiltration of T lymphocytes within tumors is associated with better outcomes in cancer patients, yet current understanding of factors that influence T-lymphocyte infiltration into tumors remains incomplete. In our study, Temozolomide (TMZ), a chemotherapeutic drug used to treat metastatic melanoma, induced T-cell infiltration into transplanted melanoma and into genitourinary (GU) tumors in mice developing spontaneous melanoma. In contrast, TMZ treatment did not increase T-cell infiltration into cutaneous tumors, despite similar increases in the expression of the (C-X-C) chemokines CXCL9 and CXCL10 in all sites after TMZ exposure. Our findings reveal that the matrix architecture of the GU tumor stroma, and its ability to present CXCL9 and CXCL10 after TMZ treatment played a key role in favouring T-cell infiltration. We subsequently demonstrate that modifications of these key elements by combined collagenase and TMZ treatment induced T-cell infiltration into skin tumors. T cells accumulating within GU tumors after TMZ treatment exhibited T helper type-1 effector and cytolytic functional phenotypes, which are important for control of tumor growth. Our findings highlight the importance of the interaction between tumor stroma and chemokines in influencing T-cell migration into tumors, thereby impacting immune control of tumor growth. This knowledge will aid the development of strategies to promote T-cell infiltration into cancerous lesions and has the potential to markedly improve treatment outcomes.

Agrin and perlecan mediate tumorigenic processes in oral squamous cell carcinoma

Oral squamous cell carcinoma is the most common type of cancer in the oral cavity, representing more than 90% of all oral cancers. The characterization of altered molecules in oral cancer is essential to understand molecular mechanisms underlying tumor progression as well as to contribute to cancer biomarker and therapeutic target discovery. Proteoglycans are key molecular effectors of cell surface and pericellular microenvironments, performing multiple functions in cancer. Two of the major basement membrane proteoglycans, agrin and perlecan, were investigated in this study regarding their role in oral cancer. Using real time quantitative PCR (qRT-PCR), we showed that agrin and perlecan are highly expressed in oral squamous cell carcinoma. Interestingly, cell lines originated from distinct sites showed different expression of agrin and perlecan. Enzymatically targeting chondroitin sulfate modification by chondroitinase, oral squamous carcinoma cell line had a reduced ability to adhere to extracellular matrix proteins and increased sensibility to cisplatin. Additionally, knockdown of agrin and perlecan promoted a decrease on cell migration and adhesion, and on resistance of cells to cisplatin. Our study showed, for the first time, a negative regulation on oral cancer-associated events by either targeting chondroitin sulfate content or agrin and perlecan levels.