Matrix metalloproteinase 7 and perlecan in oral epithelial dysplasia and carcinoma in situ: an aid for histopathologic recognition of their cell proliferation centers

Oral epithelial dysplasia: Causes, quantification, prognosis, and management challenges

Oral epithelial dysplasia is a spectrum of architectural and cytological epithelial changes caused by accumulation of genetic changes, and is associated with an increased risk of progression to squamous cell carcinoma. It is a microscopic diagnosis of immense clinical importance. The initial reports of oral potentially malignant disorders with oral epithelial dysplasia transforming to oral cancer helped in understanding the nature of oral malignancies. Since then, clinical studies on oral potentially malignant disorders have combined microscopic findings of oral epithelial dysplasia to assess the malignant transformation potential of different grades of epithelial dysplasia. A significant amount of scientific literature has amassed on oral epithelial dysplasia relating to aspects of its diagnosis and management. However, the evidence base is weak as a result of the significant variability of published research. Poorly described study methods, variability in different oral epithelial dysplasia grading systems, inter- and intra-examiner variability causing issues of reliability, inadequate sample size, and inconsistent durations of follow-up are some of the methodological issues contributing to the failure to provide dependable information. Randomized clinical trials on the malignant transformation potential of oral epithelial dysplasia and its treatment outcomes are limited. This comprehensive literature review on oral epithelial dysplasia summarizes the scientific knowledge published in the scientific literature in English since its first description. The historical development, etiological factors, grading systems, diagnostic criteria, assessment of risk factors and prevention of malignant transformation, management principles of different grades of oral epithelial dysplasia (surgical and nonsurgical), recommendations on follow-up, and prognostic indicators are discussed in detail.

Matrilysin/MMP-7 Cleavage of Perlecan/HSPG2 Complexed with Semaphorin 3A Supports FAK-Mediated Stromal Invasion by Prostate Cancer Cells

Interrupting the interplay between cancer cells and extracellular matrix (ECM) is a strategy to halt tumor progression and stromal invasion. Perlecan/heparan sulfate proteoglycan 2 (HSPG2) is an extracellular proteoglycan that orchestrates tumor angiogenesis, proliferation, differentiation and invasion. Metastatic prostate cancer (PCa) cells degrade perlecan-rich tissue borders to reach bone, including the basement membrane, vasculature, reactive stromal matrix and bone marrow. Domain IV-3, perlecan’s last 7 immunoglobulin repeats, mimics native proteoglycan by promoting tumoroid formation. This is reversed by matrilysin/matrix metalloproteinase-7 (MMP-7) cleavage to favor cell dispersion and tumoroid dyscohesion. Both perlecan and Domain IV-3 induced a strong focal adhesion kinase (FAK) dephosphorylation/deactivation. MMP-7 cleavage of perlecan reversed this, with FAK in dispersed tumoroids becoming phosphorylated/activated with metastatic phenotype. We demonstrated Domain IV-3 interacts with the axon guidance protein semaphorin 3A (Sema3A) on PCa cells to deactivate pro-metastatic FAK. Sema3A antibody mimicked the Domain IV-3 clustering activity. Direct binding experiments showed Domain IV-3 binds Sema3A. Knockdown of Sema3A prevented Domain IV-3-induced tumoroid formation and Sema3A was sensitive to MMP-7 proteolysis. The perlecan-Sema3A complex abrogates FAK activity and stabilizes PCa cell interactions. MMP-7 expressing cells destroy the complex to initiate metastasis, destroy perlecan-rich borders, and favor invasion and progression to lethal bone disease.

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.

Perlecan/HSPG2 and matrilysin/MMP-7 as indices of tissue invasion: tissue localization and circulating perlecan fragments in a cohort of 288 radical prostatectomy patients

Prostate cancer (PCa) cells use matrix metalloproteinases (MMPs) to degrade tissue during invasion. Perlecan/HSPG2 is degraded at basement membranes, in reactive stroma and in bone marrow during metastasis. We previously showed MMP-7 efficiently degrades perlecan. We now analyzed PCa tissue and serum from 288 prostatectomy patients of various Gleason grades to decipher the relationship between perlecan and MMP-7 in invasive PCa. In 157 prostatectomy specimens examined by tissue microarray, perlecan levels were 18% higher than their normal counterparts. In Gleason grade 4 tissues, MMP-7 and perlecan immunostaining levels were highly correlated with each other (average correlation coefficient of 0.52) in PCa tissue, regardless of grade. Serial sections showed intense, but non-overlapping, immunostaining for MMP-7 and perlecan at adjacent borders, reflecting the protease-substrate relationship. Using a capture assay, analysis of 288 PCa sera collected at prostatectomy showed elevated levels of perlecan fragments, with most derived from domain IV. Perlecan fragments in PCa sera were associated with overall MMP-7 staining levels in PCa tissues. Domain IV perlecan fragments were present in stage IV, but absent in normal, sera, suggesting perlecan degradation during metastasis. Together, perlecan fragments in sera and MMP-7 in tissues of PCa patients are measures of invasive PCa.

Differential immunohistochemical expression profiles of perlecan-binding growth factors in epithelial dysplasia, carcinoma in situ, and squamous cell carcinoma of the oral mucosa

The intercellular deposit of perlecan, a basement-membrane type heparan sulfate proteoglycan, is considered to function as a growth factor reservoir and is enhanced in oral epithelial dysplasia and carcinoma in situ (CIS). However, it remains unknown which types of growth factors function in these perlecan-enriched epithelial conditions. The aim of this study was to determine immunohistochemically which growth factors were associated with perlecan in normal oral epithelia and in different epithelial lesions from dysplasia and CIS to squamous cell carcinoma (SCC). Eighty-one surgical tissue specimens of oral SCC containing different precancerous stages, along with ten of normal mucosa, were examined by immunohistochemistry for growth factors. In normal epithelia, perlecan and growth factors were not definitely expressed. In epithelial dysplasia, VEGF, SHH, KGF, Flt-1, and Flk-1were localized in the lower half of rete ridges (in concordance with perlecan, 33-100%), in which Ki-67 positive cells were densely packed. In CIS, perlecan and those growth factors/receptors were more strongly expressed in the cell proliferating zone (63-100%). In SCC, perlecan and KGF disappeared from carcinoma cells but emerged in the stromal space (65-100%), while VEGF, SHH, and VEGF receptors remained positive in SCC cells (0%). Immunofluorescence showed that the four growth factors were shown to be produced by three oral SCC cell lines and that their signals were partially overlapped with perlecan signals. The results indicate that perlecan and its binding growth factors are differentially expressed and function in specific manners before (dysplasia/CIS) and after (SCC) invasion of dysplasia/carcinoma cells.

Matrilysin/matrix metalloproteinase-7(MMP7) cleavage of perlecan/HSPG2 creates a molecular switch to alter prostate cancer cell behavior

Perlecan/HSPG2, a large heparan sulfate (HS) proteoglycan, normally is expressed in the basement membrane (BM) underlying epithelial and endothelial cells. During prostate cancer (PCa) cell invasion, a variety of proteolytic enzymes are expressed that digest BM components including perlecan. An enzyme upregulated in invasive PCa cells, matrilysin/matrix metalloproteinase-7 (MMP-7), was examined as a candidate for perlecan proteolysis both in silico and in vitro. Purified perlecan showed high sensitivity to MMP-7 digestion even when fully decorated with HS or when presented in native context connected with other BM proteins. In both conditions, MMP-7 produced discrete perlecan fragments corresponding to an origin in immunoglobulin (Ig) repeat region domain IV. While not predicted by in silico analysis, MMP-7 cleaved every subpart of recombinantly generated perlecan domain IV. Other enzymes relevant to PCa that were tested had limited ability to cleave perlecan including prostate specific antigen, hepsin, or fibroblast activation protein α. A long C-terminal portion of perlecan domain IV, Dm IV-3, induced a strong clustering phenotype in the metastatic PCa cell lines, PC-3 and C4-2. MMP-7 digestion of Dm IV-3 reverses the clustering effect into one favoring cell dispersion. In a C4-2 Transwell® invasion assay, perlecan-rich human BM extract that was pre-digested with MMP-7 showed loss of barrier function and permitted a greater level of cell penetration than untreated BM extract. We conclude that enzymatic processing of perlecan in the BM or territorial matrix by MMP-7 as occurs in the invasive tumor microenvironment acts as a molecular switch to alter PCa cell behavior and favor cell dispersion and invasiveness.

COX-2, MMP-7 expression in oral lichen planus and oral squamous cell carcinoma

OBJECTIVE

To observe cyclooxygenase (COX)-2 expression in normal oral mucosa (NOM), oral lichen planus (OLP) and oral squamous cell carcinoma (OSCC) and explore its significance in the incidence of oral cancer.

METHODS

The immunohistochemical method and RT-PCR method were applied to detect the expression of COX-2 and MMP-7 in 10 cases with NOM, 33 cases of with OLP and 38 cases with OSCC.

RESULTS

The expression of COX-2 mRNA in OSCC tissues (68.4%, 26/38) was significantly higher than in the OLP (24.2%, 8/33) and NOM (0.0%, 0/10) (P<0.01). The expression of MMP-7 mRNA in OSCC tissues (65.8%, 25/38) was significantly higher than in the OLP (30.3%, 10/33) and NOM (0.0%, 0/10) (P<0.01). The expression of MMP-7 in OLP was significantly higher than in the NOM (P<0.05). There was no significant expression of COX-2 protein in NOM, and the positive rate was 42.4% (14/33) and 89.5% (34/38) in OLP and OSCC group, respectively. The COX-2 expression in cancer tissues was significantly higher than in NOM and OLP (P<0.05). The MMP-7 protein expression in cancer tissues (84.2%, 32/38) was significantly higher than in NOM (10.0%, 1/10) and in OLP (42.4%, 14/33), and the positive rate in OLP was significantly higher than in NOM (P< 0.01). The COX-2 expression was associated with clinical stage (P<0.05), the MMP-7 expression was associated with clinical stage and lymph node metastasis (P<0.05). The expressions of COX-2 and MMP-7 mRNA were positively correlated with OSCC.

CONCLUSIONS

The abnormal expressions of COX-2 and MMP-7 are closely related to the biological behavior of OSCC, the MMP-7 may be induced by COX-2, and further lead to the invasion and metastasis of OSCC.

Can immunohistochemistry serve as an alternative to subjective histopathological diagnosis of oral epithelial dysplasia?

Many attempts have been made to identify objective molecular biomarkers to diagnose and prognosticate oral epithelial dysplasia (OED) because histopathological interpretation is subjective and lacks sensitivity. The majority of these efforts describe changes in gene expression at protein level in OED as determined by immunohistochemistry (IHC). However, the literature on these putative markers of oral cancer progression is vast and varied. The main purpose of this article is to review current knowledge on biomarkers of protein expression for OED by IHC approaches. We further discuss these findings in terms of the proposed essential hallmarks of cancer cells to better understand their role in oral oncogenesis.

Podoplanin-mediated cell adhesion through extracellular matrix in oral squamous cell carcinoma

Podoplanin (PDPN), one of the representative mucin-like type-I transmembrane glycoproteins specific to lymphatic endothelial cells, is expressed in various cancers including squamous cell carcinoma (SCC). On the basis of our previous studies, we have developed the hypothesis that PDPN functions in association with the extracellular matrix (ECM) from the cell surface side. The aim of this study was to elucidate the molecular role of PDPN in terms of cell adhesion, proliferation, and migration in oral SCC cells. Forty-four surgical specimens of oral SCC were used for immunohistochemistry for PDPN, and the expression profiles were correlated with their clinicopathological properties. Using ZK-1, a human oral SCC cell system, and five other cell systems, we examined PDPN expression levels by immunofluorescence, western blotting, and real-time PCR. The effects of transient PDPN knockdown by siRNA in ZK-1 were determined for cellular functions in terms of cell proliferation, adhesion, migration, and invasion in association with CD44 and hyaluronan. Cases without PDPN-positive cells were histopathologically classified as less-differentiated SCC, and SCC cells without PDPN more frequently invaded lymphatics. Adhesive properties of ZK-1 were significantly inhibited by siRNA, and PDPN was shown to collaborate with CD44 in cell adhesion to tether SCC cells with hyaluronan-rich ECM of the narrow intercellular space as well as with the stromal ECM. There was no siRNA effect in migration. We have demonstrated the primary function of PDPN in cell adhesion to ECM, which is to secondarily promote oral SCC cell proliferation.

Growth hormone-releasing hormone receptor splice variant 1 is frequently expressed in oral squamous cell carcinomas

The expression of growth hormone-releasing hormone (GHRH) splice variant 1 (SV1) receptor in neoplastic lesions of the oral cavity was assessed. The sensitivity of HaCaT keratinocytes to GHRH analogs was also evaluated. Thirty-three benign precancerous oral lesions and 27 squamous cell carcinomas of the oral cavity were evaluated by immunohistochemistry for SV1 expression. SV1 expression in HaCaT keratinocytes was assessed by western blot. HaCaT proliferation was evaluated by cell counting. Anti-SV1 immunoreactivity was detected in only 9% (three of 33) precancerous lesions (one hyperplasia and two dysplasias), while 44% (12 of 27) carcinomas were positive for SV1 (p<0.002). GHRH(1-29)NH(2) and GHRH agonist JI-38 stimulated HaCaT proliferation in vitro, and this effect was blocked by GHRH antagonists. These results indicate that SV1 expression may be associated with the transition of precancerous lesions to carcinomas of the oral epithelium. GHRH antagonists may be useful for the management of the disease.

Nuclear translocation of β-catenin synchronized with loss of E-cadherin in oral epithelial dysplasia with a characteristic two-phase appearance

AIMS

One of the important histopathological characteristics of oral epithelial dysplasia is a two-phase appearance of rete processes, comprising an upper layer of keratinized cells and a lower layer of basaloid cells, and thereby creating a sharp contrast between these two separate cell populations. The aim of this study was to determine the cellular adhesion status of the basaloid cells.

METHODS AND RESULTS

Immunohistochemistry for β-catenin, E-cadherin and their related molecules was carried out in surgical specimens of two-phase epithelial dysplasia of the oral mucosa. The lower-half basaloid cells and the upper keratinized cells were microdissected separately, and extracted DNA samples were subjected to methylation-specific polymerase chain reaction amplification for E-cadherin. β-Catenin was immunolocalized within the nuclei and cytoplasm of Ki67-positive lower-half basaloid cells, as well as on the cell membrane of upper parakeratotic cells. The basaloid cells of the lower-half were also positive for matrix metalloproteinase-7 and cyclin D1, β-catenin target gene products, α-dystroglycan, tenascin-C, and perlecan, but not for E-cadherin. The promoter region of the E-cadherin gene was hypermethylated.

CONCLUSIONS

The solid proliferation of lower-half E-cadherin-free basaloid cells is enhanced by Wnt signalling cascades, as well as by the intraepithelial extracellular matrix or its bound growth factors.

Enhanced expression of podoplanin in oral carcinomas in situ and squamous cell carcinomas

OBJECTIVE

Podoplanin, a known lymphatic endothelial cell marker, has been reported to be expressed in various types of cancer. To elucidate the expression of podoplanin in precancerous lesions, we examined the immunohistochemical profiles of podoplanin in oral squamous epithelial lesions.

METHOD

We studied a total of 298 foci of squamous cell carcinoma (SCC), carcinoma in situ (CIS), epithelial dysplasia, and hyperplastic and/or normal epithelial lesions by immunohistochemistry using D2-40.

RESULTS

There was no positivity for podoplanin in normal or hyperplastic epithelia, while all of the CIS and SCC foci stained positive. Approximately one third of the mild dysplasia foci (10 of 36 foci, 28%) and 80% of moderate dysplasia foci (78/98) showed grade 1 positive reactions (positive only in the 1st layer). Grade 2 reactions (up to 4th layer) were seen in 4 of 98 moderate dysplasia foci (4%), 29 of 74 CIS foci (39%), and 3 of 30 SCC foci (10%). Grade 3 reactions (to more than 5th layer) were found in 35 (47%) CIS foci and 26 (87%) SCC foci.

CONCLUSIONS

The relationship between the present histological categorization and podoplanin grade was statistically significant. D2-40 expression is considered to be related to the severity of oral precancerous lesions.

Emergence of keratin 17 vs. loss of keratin 13: their reciprocal immunohistochemical profiles in oral carcinoma in situ

To evaluate differential expressions for keratin (K) subtypes 13 and 17 in oral borderline malignancies, we examined 67 surgical specimens of the oral mucosa for their immunohistochemical profiles. From those specimens, 173 foci of epithelial dysplasia, 152 foci of carcinoma in situ (CIS), and 82 foci of squamous cell carcinoma (SCC) were selected according to our diagnostic criteria, along with 20 areas of normal epithelia. In normal epithelia, there was no K17 positivity (0%), whereas definite K13 positivity (100%) was observed. The same tendencies were obtained in mild (undefined) and moderate (true) epithelial dysplasias (K17: 0%; K13: 100%). In contrast, all CIS (100%) had K17 positivities, while K13 positivities were lost in many of them (7%). Similar tendencies were confirmed in invasive SCC (K17: 100%, K13: 4%). Simultaneous immunopositivities for K17 and K13 were found only in SCC (7%) and CIS (4%) foci with distinct keratinization. These foci also showed K10 positivities, though K10 positive areas were not identical to K13 positive areas. The results indicate that expressions of K17 and K13 are reciprocal in oral epithelial lesions and that the K17 emergence is related to malignancies.

The role of matrix metalloproteinases in recurrent tonsillitis

OBJECTIVE

The aim of this study was to investigate the status of matrix metalloproteinases (MMP-2, MMP-7, MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) due to dysregulated turnover of connective tissue matrices in children with recurrent tonsillitis (RT).

METHODS

Forty-four patients with RT were enrolled in the study. All patients with RT were graded according to the hypertrophy degree of the tonsillar tissue from grade I to grade IV. Patients with grade I tonsillar hypertrophy and grade II tonsillar hypertrophy were accepted as group A, patients with grade III tonsillar hypertrophy and grade IV tonsillar hypertrophy were accepted as group B Tonsillectomy was performed via the usual dissection-snare method. Tonsillar specimens of superficial and core region were evaluated for MMP-2, MMP-7, MMP-9 and TIMP-1 analysis.

RESULTS

There was no statistical significance according to the MMP-2, MMP-7, MMP-9 and TIMP-1 activity of superficial part and core regions in both groups individually, MMP-9 level of both the superficial and core regions in group B had statistical significant higher results than group A (p=0.026, p=0.06 respectively). MMP-7 level of the superficial part in group B patients also had statistical significant higher results than group A (p=0.025). However, there was no statistical difference found between superficial and core region MMP-2 and TIMP-1 levels of group A and group B. Related to this, balance between MMP-7-9 and TIMP-1 activities tended to slip MMP-7 and MMP-9 sides with increased tonsillar grade.

CONCLUSIONS

Results from this study suggest that the presence of MMPs in tonsil tissue consolidates the involvement of degraded extracellular matrix proteins in the pathophysiology of chronic tonsillitis. MMPs activity showed diffuse dissemination in the tonsillar tissue and especially MMP-9 and MMP-7 are the main promoters of the extracellular matrix that responded to inflammatory changes in the tonsillar tissue. Further studies are needed concerning the possible efficiency of selective MMP inhibitors on tonsillar tissue.