Caveolin-1 expression in oral lichen planus, dysplastic lesions and squamous cell carcinoma

A Molecular Hypothesis on Malignant Transformation of Oral Lichen Planus: A Systematic Review and Meta-Analysis of Cancer Hallmarks Expression in This Oral Potentially Malignant Disorder

We aimed to qualitatively and quantitatively analyze, through a systematic review and meta-analysis, the current evidence on the differential expression of the hallmarks of cancer in oral lichen planus (OLP) samples, in order to know the earliest molecular mechanisms that could be involved in the malignant transformation of this oral potentially malignant disorder. We searched MEDLINE/PubMed, Embase, Web of Science, and Scopus for studies published before November 2023. We evaluated the methodological quality of studies and carried out meta-analyses to fulfill our objectives. Inclusion criteria were met by 110 primary-level studies, with 7065 OLP samples, in which the expression of 104 biomarkers were analyzed through immunohistochemistry. Most OLP samples showed sustained cell proliferation signaling (65.48%, 95%CI = 51.87-78.02), anti-apoptotic pathways (55.93%, 95%CI = 35.99-75.0), genome instability (48.44%, 95%CI = 13.54-84.19), and tumor-promoting inflammation events (83.10%, 95%CI = 73.93-90.74). Concurrently, OLP samples also harbored tumor growth suppressor mechanisms (64.00%, 95%CI = 53.27-74.12). In conclusion, current evidence indicates that molecular mechanisms promoting hyperproliferative signaling, an antiapoptotic state with genomic instability, and an escape of epithelial cells from immune destruction, are developed in LP-affected oral mucosa. It is plausible that these events are due to the actions exerted by the chronic inflammatory infiltrate. Malignant transformation appears to be prevented by tumor suppressor genes, which showed consistent upregulation in OLP samples.

Evaluation of BIRC6 Expression in Oral Squamous Cell Carcinoma, Epithelial Dysplasia, Lichen Planus with and without Dysplasia, and Hyperkeratosis

BACKGROUND

BIRC6, regarded as the pivotal member of the inhibitor of the apoptosis (IAP) family, has been linked to the development of different types of cancer in humans. The objective of this study was to examine the expression of BIRC6 in various oral conditions, including OLP with dysplasia (OLPD), hyperkeratosis (HK), OLP, epithelial dysplasia (ED), and oral squamous cell carcinoma (OSCC), to investigate its potential involvement in the development of OSCC and the pathogenesis and malignant transformation of OLP, which is known as a precancerous condition.

METHODS

In this retrospective cross-sectional study, 99 cases, consisting of 19 cases of OSCC, 21 cases of ED, 23 cases of OLP, 20 cases of OLPD, and 16 cases of HK as the control group, were investigated regarding BIRC6 expression by immunohistochemical staining. After that, the immunohistochemical expression of BIRC6 in the epithelial compartment was analyzed. Statistical analysis was performed to investigate the relationship between the expression of BIRC6 and clinicopathological variables. The statistical analysis of the data involved the use of one-way ANOVA, post hoc Tukey, Kruskal-Wallis, Chi-square, Spearman's correlation, and Mann-Whitney tests. The significance level was set at p < 0.05.

RESULTS

Positive BIRC6 staining was found in 91.7% of the subjects of OLP, 88.1% of HK, 86.1% of ED, 93% of OLPD, and 94.7% of OSCC. OSCC showed the highest BIRC6 expression (p = 0.00). The average total staining score was remarkably greater in OSCC and dysplastic lesions compared with HK (p = 0.00, p = 0.00).

CONCLUSIONS

While the current study suggested that BIRC6 may play a role in the tumorigenesis of OSCC, its role in the malignant transformation of OLP has yet to be definitively established.

Loss of Caveolin-1 Expression in Tumor Cells is Associated with Increased Aggressiveness and Cell Invasion in Oral Squamous Cell Carcinoma

BACKGROUND

Changes in Caveolin-1 (CAV-1) expression are related to tumorigenesis. The aim of this study was to evaluate the role of CAV-1 in tumor progression in oral squamous cell carcinoma (SCC) tissue samples and the effect of CAV-1 silencing on two oral tongue SCC (OTSCC) cell lines (SCC-25, from a primary tumor, and HSC-3 from lymph node metastases).

METHODS

Mycroarray hybridization, mRNA expression, and immunohistochemistry were performed on OSCC tissue samples and corresponding non-tumoral margin tissues. The effects of CAV-1 silencing (siCAV-1) on cell viability, membrane fluidity, on the expression of epithelial to mesenchymal transition (EMT) markers and on cell migration and invasion capacity of OTSCC cell lines were evaluated.

RESULTS

Microarray showed a greater CAV-1 expression (1.77-fold) in OSCC tumors than in non-tumoral tissues and 2.0-fold more in less aggressive OSCCs. However, significant differences in CAV-1 gene expression were not seen between tumors and non-tumoral margins nor CAV-1 with any clinicopathological parameters. CAV-1 protein was localized both in carcinoma and in spindle cells of the tumor microenvironment (TME), and CAV-1 positive TME cells were associated with smaller/more aggressive tumors, independent of the carcinoma cells' expression. Silencing of CAV-1 increased cell viability only in SCC-25 cells. It also stimulated the invasion of HSC-3 cells and increased ECAD and BCAT mRNA in these cells; however, the protein levels of the EMT markers were not affected.

CONCLUSION

Decreased expression of CAV-1 by tumor cells in OSCC and an increase in the TME were associated with increased cell invasiveness and tumor aggressiveness.

Evaluation of Paxillin Expression in Epithelial Dysplasia, Oral Squamous Cell Carcinoma, Lichen Planus with and without Dysplasia, and Hyperkeratosis: A Retrospective Cross-Sectional Study

BACKGROUND

Paxillin is a cytoskeletal protein involved in the pathogenesis of several types of cancers. However, the roles of paxillin in epithelial dysplasia (ED), oral squamous cell carcinoma (OSCC), oral lichen planus with dysplasia (OLPD), hyperkeratosis (HK), and oral lichen planus (OLP) have remained unnoticed in the literature. This study aimed to evaluate its attainable functions in the pathogenesis and malignant transformation of potentially malignant oral epithelium and benign lesions.

METHODS

In this retrospective cross-sectional study, paxillin expression was investigated in 99 tissue samples, including 18 cases of OSCC, 21 ED, 23 OLP, 21 OLPD, and 16 cases of HK. The tissue sections also underwent immunohistochemical paxillin staining using 3,3-diaminobenzidine (DAB) chromogen. The intensity, location, and percentage of staining were examined across all groups. Data were analyzed using the Shapiro-Wilk test, ANOVA, Pearson chi-square, Kruskal-Wallis, and Dunn's post hoc test.

RESULTS

The cytoplasmic percentage and intensity staining of Paxillin expression were evident in the central/suprabasal and basal/peripheral layers of all the obtained samples. The final staining score was significantly higher in OSCC and dysplasia compared to HK and OLP (p = 0.004). It was found that paxillin expression is associated with the grade of dysplastic samples (p < 0.001).

CONCLUSION

The present study provides evidence that paxillin may be involved in the pathogenesis of OSCC and the development and progression of dysplastic tissue, since the paxillin expression was higher than that of HK and OLP.

Cholesterol Is a Regulator of CAV1 Localization and Cell Migration in Oral Squamous Cell Carcinoma

Cholesterol plays an important role in cancer progression, as it is utilized in membrane biogenesis and cell signaling. Cholesterol-lowering drugs have exhibited tumor-suppressive effects in oral squamous cell carcinoma (OSCC), suggesting that cholesterol is also essential in OSCC pathogenesis. However, the direct effects of cholesterol on OSCC cells remain unclear. Here, we investigated the role of cholesterol in OSCC with respect to caveolin-1 (CAV1), a cholesterol-binding protein involved in intracellular cholesterol transport. Cholesterol levels in OSCC cell lines were depleted using methyl-β-cyclodextrin and increased using the methyl-β-cyclodextrin-cholesterol complex. Functional analysis was performed using timelapse imaging, and CAV1 expression in cholesterol-manipulated cells was investigated using immunofluorescence and immunoblotting assays. CAV1 immunohistochemistry was performed on surgical OSCC samples. We observed that cholesterol addition induced polarized cell morphology, along with CAV1 localization at the trailing edge, and promoted cell migration. Moreover, CAV1 was upregulated in the lipid rafts and formed aggregates in the plasma membrane in cholesterol-added cells. High membranous CAV1 expression in tissue specimens was associated with OSCC recurrence. Therefore, cholesterol promotes the migration of OSCC cells by regulating cell polarity and CAV1 localization to the lipid raft. Furthermore, membranous CAV1 expression is a potential prognostic marker for OSCC patients.

Cholesterol depletion affects caveolin-1 expression, migration and invasion of oral tongue squamous cell carcinoma cell lines

INTRODUCTION

Cholesterol is a key lipid molecule within cell membranes. This is especially true in cavelolas, invaginated membrane nanodomains, which present the protein caveolin-1 (CAV-1). It is important to note that this structure is involved in many cell signalling pathways. Additionally, high cholesterol is seen in different tumor types but little is known in regards to oral tongue squamous cell carcinoma (OTSCC). The aim of this study was to evaluate the influence of cholesterol depletion on primary (SCC-25) and metastatic (HSC-3) OTSCC cell lines.

MATERIALS AND METHODS

Cell membrane fluidity, cell viability, gene and protein expression of CAV-1 and of epithelial-mesenchymal transition (EMT) markers, cell migration in Myogel and invasion-myoma assay were evaluated after cholesterol depletion with methyl-β-cyclodextrin (MβCD - 7.5, 10 or 15 mM) RESULTS: Decreased cell viability and increased membrane fluidity of SCC-25 cells was seen with cholesterol depletion but cell viability was less affected and there was no effect on membrane fluidity in HSC-3. Cholesterol depletion also decreased CAV-1 at 6 h but increased it after 24 h.; both epithelial and mesenchymal EMT genes were upregulated after 6 h, followed by downregulation at 24 h in SCC-25. In HSC-3, CAV-1 was downregulated, and E-cadherin gene (ECAD) was upregulated at 6 h. Only the protein β-catenin in SCC-25 was affected, and cell migration of both cell lines was decreased, affecting SCC-25 more intensely. The invasive capacity within human myoma organotypic model was increased in SCC-25 and decreased in HSC-3.

CONCLUSION

Cholesterol depletion affects CAV-1 and ECAD inversely. This affect also depends on cell type since the invasive capacity was augmented in primary cells while decreased in metastatic cells.

Differential proteomic expression in indolent vulvar lichen sclerosus, transforming vulvar lichen sclerosus and normal vulvar tissue

Vulvar lichen sclerosus (VLS) confers approximately 3% risk of malignant transformation to vulvar squamous cell carcinoma (VSCC). We used unbiased proteomic methods to identify differentially expressed proteins in tissue of patients with VLS who developed VSCC compared to those who did not. We used laser capture microdissection- and nanoLC-tandem mass spectrometry to assess protein expression in individuals in normal vulvar tissue (NVT, n = 4), indolent VLS (no VSCC after at least 5 years follow-up, n = 5) or transforming VSCC (preceding VSCC, n = 5). Interferon-γ and antigen-presenting pathways are overexpressed in indolent and transforming VLS compared to NVT. There was differential expression of malignancy-related proteins in transforming VLS compared to indolent VLS (CAV1 overexpression, AKAP12 underexpression), particularly in the EIF2 translation pathway, which has been previously implicated in carcinogenesis. Results of this study provide additional molecular evidence supporting the concept that VLS is a risk factor for VSCC and highlights possible future biomarkers and/or therapeutic targets.

Cathepsin-B and caveolin-1 gene expressions in oral lichen planus and oral squamous cell carcinoma

BACKGROUND

Given the importance of the role of cellular changes in the prognosis and diagnosis of malignancies of the head and neck, we examined in this study the gene expressions of cathepsin-B (Cat-B) and caveolin-1 (Cav-1) which are in cell membranes structures involved in carcinogenesis, in oral squamous cell carcinoma (OSCC) and oral lichen planus (OLP) and compared them to controls. We also investigated their relationship to clinicopathological indices.

METHODS AND RESULTS

In this case-control study, 29 paraffin blocks of OLP patients were compared to 29 paraffin blocks of OSCC samples as well as 28 paraffin blocks of normal oral tissue. Real-time quantitative PCR was performed to determine gene expressions and results were analyzed for their relationship to clinical data using chi-square, Kruskal-Wallis and Mann-Whitney tests.

RESULTS

The mean age of OSCC and OLP patients were 59.24 ± 15.04 and 48.79 ± 14.17 years, respectively. The Cat-B and Cav-1 expressions were significantly higher in OSCC and OLP samples compared to control (p < 0.001). The highest expression was found in OSCC samples. The difference between OLP and control samples for Cat-B and Cav-1 expression was significant. There was no association between the gene expression and age, gender, duration of disease, Thongprasom score, smoking and cutaneous lichen planus. However, the expressions were related to the grade and stage of OSCC samples (P = 0.01, P = 0.02).

CONCLUSION

The gene expressions of Cat-B and Cav-1 in OSCC were associated with the stage and grade of lesions. Therefore, they appear to be useful in predicting the biological behavior of OSCC and malignant transformation of OLP, although this process is multi factorial and more investigations are needed.

Differences in the expression of caveolin-1 isoforms in cancer-associated and normal fibroblasts of patients with oral squamous cell carcinoma

OBJECTIVES

For many years, tumor development has been viewed as a cell-autonomous process; however, today we know that the tumor microenvironment (TME) and especially cancer-associated fibroblasts (CAFs) significantly contribute to tumor progression. Caveolin-1 (Cav-1) is a scaffolding protein which is involved in several cancer-associated processes as important component of the caveolae. Our goal was to shed light on the expression of the two different isoforms of Cav-1 in normal fibroblasts (NFs) and CAFs of patients with oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Fibroblasts from normal mucosa and CAFs were isolated and propagated in vitro. Gene expression of the different Cav-1 isoforms was assessed via quantitative real-time PCR (qPCR) and supplemented by protein expression analysis.

RESULTS

We could show that the Cav-1β isoform is more highly expressed in NFs and CAFs compared to Cav-1α. Furthermore, the different Cav-1 isoforms tended to be differently expressed in different tumor stages. However, this trend could not be seen consistently, which is in line with the ambiguous role of Cav-1 in tumor progression described in literature. Western blotting furthermore revealed that NFs and CAFs might differ in the oligomerization profile of the Cav-1 protein.

CONCLUSION

These differences in expression of Cav-1 between NFs and CAFs of patients with OSCC confirm that the protein might play a role in tumor progression and is of interest for further analyses.

CLINICAL RELEVANCE

Our findings support a possible role of the two isoforms of Cav-1 in the malignant transformation of OSCC.

Expression of caveolin-1 in tooth germ, ameloblastoma and ameloblastic carcinoma

BACKGROUND

The caveolin-1 protein (structural component of membrane caveolae) plays important roles in several biological functions, such as endocytosis, cell adhesion, and cell signaling. However, this protein has been associated with mechanisms of tumorigenesis in several neoplasms. The expression patterns and roles of caveolin-1 in the oral epithelium and in embryonic and odontogenic tumor tissues are still unclear.

MATERIAL AND METHODS

The expression of caveolin-1 was evaluated in samples of the normal gingival epithelium (n=7), human tooth germ (TG) (n=12), ameloblastoma (AM) (n=83), and ameloblastic carcinoma (AC) (n=9) by immunohistochemistry. Additionally, AM samples were analyzed by qRT-PCR and Western blot.

RESULTS

Most TG (91.7%), AM (73.5%) and AC (100%) samples showed diverse patterns of immunohistochemical positivity for caveolin-1, while only one gingival sample was positive. The transcript levels of cav-1 were significantly upregulated by 14.9-fold in AM tissue (P = 0.0014) compared to those in normal gingival epithelial tissue, as shown by qRT-PCR. Presence of caveolin-1 protein was confirmed by Western blot analysis. The caveolin-1 immunoexpression patterns throughout the stages of TG show its importance during odontogenesis.

CONCLUSIONS

The overexpression of caveolin-1 in AM and AC compared to its expression in normal gingival epithelium (adult tissue) suggests a possible role of caveolin-1 in protumoral events, but due to the similar immunoexpression observed in AM and AC, caveolin-1 may not necessarily participate in the malignant transformation process. However, future studies are needed to clarify and confirm these hypotheses.

Distinctive expression profiles of Caveolin-1 and Notch-1 protein in patients with nasal polyps or sinonasal inverted papillomas

BACKGROUND

Nasal polyposis (NP) and sinonasal inverted papillomas (SIP) are considered benign lesions capable of recurrence or malignant transformation although not with the same prevalence. Since fluctuations of Caveolin-1 and Notch-1 proteins expression have been reported in many pathologies, the current study aimed to investigate their involvement in the epithelial transformation observed in SIPs compared to NP.

METHODS

Immunohistochemical expression of Caveolin-1 and Notch-1 proteins was assessed in 104 patients with sinonasal lesions (45 NP, 45 SIP and 14 NP with SIP), semiquantively (percentage times intensity). Proteins expression profiles were evaluated statistically for their correlation with patients demographic and clinicopathological variables (grade of dysplasia, inflammation, recurrence) as well as with markers of proliferation (Ki67) and apoptosis (7-AAD) as determined by flow cytometry analysis.

RESULTS

SIP lesions presented increased Caveolin-1 immunopositivity compared to NP (62.2%, vs 40.9%; p = 0.045). Cytoplasmic staining was observed only in epithelium's basal and suprabasal layers. Caveolin-1 positivity was not related to Ki67 expression, apoptosis, inflammation or dysplasia, eventhough 81.8% of highly immunopositive lesions were dysplastic (p = 0.03). Also, smokers presented significantly increased immunopositivy (p = 0.03). In contrast SIP lesions presented reduced Notch-1 expression compared to NP (68.9% vs 100%; p < 0.001). Dysplastic lesions presented low Notch-1 immunopositivity (p < 0.001). Enhancement of Notch-1 gene expression was also associated with inflammation.

CONCLUSIONS

The herein presented data suggest that the expression profiles of Caveolin-1 and Notch-1 proteins in sinonasal pathologies are distinctive and that could be explored as potential targets for the development of alternative therapeutic approaches.