Maspin expression in CIN 3, microinvasive squamous cell carcinoma, and invasive squamous cell carcinoma of the uterine cervix

Prognostic role of maspin expression in patients with cervical dysplasia and cervical cancer

AIM

Mammary serine protease inhibitor (maspin) acts as a tumor suppressor through the inhibition of cancer cell invasion and metastasis. Paradoxically, maspin levels are increased in some types of malignant cells. The aim of this study was to investigate the maspin expression in cervical dysplasia and cervical cancer, and to analyze its' relation with survival.

METHODS

Maspin expression was detected by immunohistochemistry using labeled streptavidin biotin method to determine cytoplasmic and nuclear maspin expressions in cervical intraepithelial neoplasia grade 1 (CIN1), cervical intraepithelial neoplasia grade 2 (CIN2), cervical intraepithelial neoplasia grade 3 (CIN3) and cervical cancer.

RESULTS

A total of 89 patients with CIN (29 cases of CIN1, 30 cases of CIN2 and 30 cases of CIN3), and 27 patients with cervical cancer were included to the study. 7.8% of the patients with CIN had maspin staining positivity. On the other hand maspin staining was positive in 20 of 27 patients (74.1%) with cervical carcinoma (P = 0.001). Of these patients 20 (100%) had cytoplasmic, and 8 (40%) had nuclear maspin staining positivity. Cytoplasmic maspin immunoreactive scores were found to be significantly higher in carcinoma group when compared to the patients with CIN1/3 (respectively; P = 0.01, P = 0.02). No difference was noted for nuclear maspin expression. Significant overall survival advantage was detected for patients with nuclear maspin staining (P = 0.03).

CONCLUSION

The current study shows that nuclear maspin expression is related with better overall survival in cervical cancer. Maspin staining can be a useful diagnostic marker to discriminate cervical intraepithelial neoplasia from cervical carcinoma.

Subcellular expression of maspin – from normal tissue to tumor cells

Maspin or SerpinB5, a member of the serine protease inhibitor family, was shown to function as a tumor suppressor, especially in carcinomas. It seems to inhibit invasion, tumor cells motility and angiogenesis, and promotes apoptosis. Maspin can also induce epigenetic changes such as cytosine methylation, de-acetylation, chromatin condensation, and histone modulation. In this review, a comprehensive synthesis of the literature was done to present maspin function from normal tissues to pathologic conditions. Data was sourced from MEDLINE and PubMed. Study eligibility criteria included: Published in English, between 1994 and 2019, specific to humans, and with full-text availability. Most of the 118 studies included in the present review focused on maspin immunostaining and mRNA levels. It was shown that maspin function is organ-related and depends on its subcellular localization. In malignant tumors, it might be downregulated or negative (e.g., carcinoma of prostate, stomach, and breast) or upregulated (e.g., colorectal and pancreatic tumors). Its subcellular localization (nuclear vs cytoplasm), which can be proved using immunohistochemical methods, was shown to influence both tumor behavior and response to chemotherapy. Although the number of maspin-related papers increased, the exact role of this protein remains unknown, and its interpretation should be done with extremely high caution.

Re-expression of Selected Epigenetically Silenced Candidate Tumor Suppressor Genes in Cervical Cancer by TET2-directed Demethylation

DNA hypermethylation is extensively explored as therapeutic target for gene expression modulation in cancer. Here, we re-activated hypermethylated candidate tumor suppressor genes (TSGs) (C13ORF18, CCNA1, TFPI2, and Maspin) by TET2-induced demethylation in cervical cancer cell lines. To redirect TET2 to hypermethylated TSGs, we engineered zinc finger proteins (ZFPs), which were first fused to the transcriptional activator VP64 to validate effective gene re-expression and confirm TSG function. ChIP-Seq not only revealed enriched binding of ZFPs to their intended sequence, but also considerable off-target binding, especially at promoter regions. Nevertheless, results obtained by targeted re-expression using ZFP-VP64 constructs were in line with cDNA overexpression; both revealed strong growth inhibition for C13ORF18 and TFPI2, but not for CCNA1 and Maspin. To explore effectivity of locus-targeted demethylation, ZFP-TET2 fusions were constructed which efficiently demethylated genes with subsequent gene re-activation. Moreover, targeting TET2 to TFPI2 and C13ORF18, but not CCNA1, significantly decreased cell growth, viability, and colony formation in cervical cancer cells compared to a catalytically inactive mutant of TET2. These data underline that effective re-activation of hypermethylated genes can be achieved through targeted DNA demethylation by TET2, which can assist in realizing sustained re-expression of genes of interest.

Expression and localization of maspin in cervical cancer and its role in tumor progression and lymphangiogenesis

Objectives

Cervical cancer is the most common malignant tumor in female reproductive tract and primarily metastasizes through the lymphatic system that will affect prognosis of patients. Maspin, a member of the serine protease inhibitors (serpins) super family, has recently been indicated as a tumor suppressor in many cancers. In this study, we investigated the clinical significance of maspin expression, especially the subcellular location of maspin and its functional role in progression and lymphangiogenesis, in cervical squamous cell carcinoma.

Methods

Labelled streptavidin biotin method (LSAB) was used to determine cytoplasmic and nuclear maspin expressions, respectively, in 13 cases of normal cervix, 15 cases of cervical intraepithelial neoplasia grade 3 (CIN3), 62 cases of squamous cell carcinoma (SCC) of the uterine cervix, and 13 cases of pelvic lymphatic nodes which were all positive lymphatic nodes in our selected cancer cases. LSAB is also used to detect podoplanin which is used for counting density of lymphatic microvessels (LMVD). The clinical significance of subcellular maspin expression and the relationship between maspin expression and LMVD in cervical cancer are analyzed.

Results

Both cytoplasmic and nuclear maspin expressions in SCC were significantly weaker than those of normal cervix and CIN3. Nuclear maspin expression showed a peak in CIN3 and then dropped in SCC. Declined maspin expression was correlated with later clinical stage, increased LMVD, and lymphatic metastasis.

Conclusions

Our results suggest that subcellular location of maspin expression is a potential predictive factor in tumor progression and in patients’ prognosis of cervical cancer, and maspin plays a suppression role in lymphangiogenesis and metastasis.

Maspin: molecular mechanisms and therapeutic implications

Maspin, a non-inhibitory member of the serine protease inhibitor superfamily, has been characterized as a tumor suppressor gene in multiple cancer types. Among the established anti-tumor effects of Maspin are the inhibition of cancer cell invasion, attachment to extracellular matrices, increased sensitivity to apoptosis, and inhibition of angiogenesis. However, while significant experimental data support the role of Maspin as a tumor suppressor, clinical data regarding the prognostic implications of Maspin expression have led to conflicting results. This highlights the need for a better understanding of the context dependencies of Maspin in normal biology and how these are perturbed in the context of cancer. In this review, we outline the regulation and roles of Maspin in normal and developmental biology while discussing novel evidence and emerging theories related to its functions in cancer. We provide insight into the immense therapeutic potential of Maspin and the challenges related to its successful clinical translation.

Immunohistochemical features of 3,3',4,4'-tetrachloroazobenzene-induced rat gingival lesions

Gingival lesions of squamous hyperplasia, cystic keratinizing hyperplasia (CKH), and squamous cell carcinoma (SCC) can be induced in rats treated by chronic gavage with 10-100 mg/kg 3,3',4,4'-tetrachloroazobenzene. We evaluated gingival squamous hyperplasia (GSH), CKH, and SCC for the immunohistochemical pattern of expression of carcinogenesis-associated markers. The 3 types of lesions and controls were stained with proliferation markers (proliferating cell nuclear antigen [PCNA] and cyclin-D1), tumor-suppressor markers (β-catenin and mammary serine protease inhibitor [maspin]) and stroma-related markers (α-smooth muscle actin [SMA] and osteonectin/SPARC). The lesions had common immunohistochemical characteristics that differed in their expression patterns among the various diagnoses. PCNA and cyclin-D1 expression was higher in GSH, CKH, and SCC than in controls. The normal membranous expression of β-catenin was lower in GSH, and almost absent in CKH and SCC. Maspin expression was similar in GSH and controls, whereas both CKH and SCC showed decreased expression. SMA and/or osteonectin/SPARC were seen in stromal cells in CKH and SCC. Collectively, there appears to be a progression from hyperplastic and cystic lesions toward malignancy based on the morphological changes, supported by the expression of carcinogenesis-associated proteins. The exact sequence of events leading to SCC remains to be defined in a time-dependent manner.

Aberrant signaling pathways in squamous cell lung carcinoma

Lung cancer is the second most commonly occurring non-cutaneous cancer in the United States with the highest mortality rate among both men and women. In this study, we utilized three lung cancer microarray datasets generated by previous researchers to identify differentially expressed genes, altered signaling pathways, and assess the involvement of Hedgehog (Hh) pathway. The three datasets contain the expression levels of tens of thousands genes in normal lung tissues and squamous cell lung carcinoma. The datasets were combined and analyzed. The dysregulated genes and altered signaling pathways were identified using statistical methods. We then performed Fisher’s exact test on the significance of the association of Hh pathway downstream genes and squamous cell lung carcinoma.

395 genes were found commonly differentially expressed in squamous cell lung carcinoma. The genes encoding fibrous structural protein keratins and cell cycle dependent genes encoding cyclin-dependent kinases were significantly up-regulated while the ones encoding LIM domains were down. Over 100 signaling pathways were implicated in squamous cell lung carcinoma, including cell cycle regulation pathway, p53 tumor-suppressor pathway, IL-8 signaling, Wnt-β-catenin pathway, mTOR signaling and EGF signaling. In addition, 37 out of 223 downstream molecules of Hh pathway were altered. The P-value from the Fisher’s exact test indicates that Hh signaling is implicated in squamous cell lung carcinoma.

Numerous genes were altered and multiple pathways were dysfunctional in squamous cell lung carcinoma. Many of the altered genes have been implicated in different types of carcinoma while some are organ-specific. Hh signaling is implicated in squamous cell lung cancer, opening the door for exploring new cancer therapeutic treatment using GLI antagonist GANT 61.

Large-scale analysis of protein expression changes in human keratinocytes immortalized by human papilloma virus type 16 E6 and E7 oncogenes

Background

Infection with high-risk type human papilloma viruses (HPVs) is associated with cervical carcinomas and with a subset of head and neck squamous cell carcinomas. Viral E6 and E7 oncogenes cooperate to achieve cell immortalization by a mechanism that is not yet fully understood. Here, human keratinocytes were immortalized by long-term expression of HPV type 16 E6 or E7 oncoproteins, or both. Proteomic profiling was used to compare expression levels for 741 discrete protein features.

Results

Six replicate measurements were performed for each group using two-dimensional difference gel electrophoresis (2D-DIGE). The median within-group coefficient of variation was 19–21%. Significance of between-group differences was tested based on Significance Analysis of Microarray and fold change. Expression of 170 (23%) of the protein features changed significantly in immortalized cells compared to primary keratinocytes. Most of these changes were qualitatively similar in cells immortalized by E6, E7, or E6/7 expression, indicating convergence on a common phenotype, but fifteen proteins (~2%) were outliers in this regulatory pattern. Ten demonstrated opposite regulation in E6- and E7-expressing cells, including the cell cycle regulator p16^INK4a; the carbohydrate binding protein Galectin-7; two differentially migrating forms of the intermediate filament protein Cytokeratin-7; HSPA1A (Hsp70-1); and five unidentified proteins. Five others had a pattern of expression that suggested cooperativity between the co-expressed oncoproteins. Two of these were identified as forms of the small heat shock protein HSPB1 (Hsp27).

Conclusion

This large-scale analysis provides a framework for understanding the cooperation between E6 and E7 oncoproteins in HPV-driven carcinogenesis.

Maspin Expression in Oral Squamous Cell Carcinoma

Maspin (mammary serine protease inhibitor) is a member of the serpin superfamily of protease inhibitors and it has a role as a tumor suppressor. Maspin has been reported to be important in processes relevant to tumor growth and metastasis such as cell invasion, angiogenesis, and apoptosis. A high expression of maspin was correlated with better rates of survival and absence of nodal metastases in head and neck squamous cell carcinoma. In contrast, some studies have shown that maspin overexpression is correlated with a poor prognosis in pancreatic and ovarian cancers and in lung adenocarcinoma. The aim of this study was an immunohistochemical evaluation of the maspin expression in oral squamous cell carcinoma and thus 89 patients were evaluated. Maspin expression in oral squamous cell carcinoma was significantly associated with the tumor differentiation grade (chi test: P = 0.0318) and the lymph node status (chi test: P < 0.005), but not with the tumor stage (chi test: P = 0.666). Metastatic involvement of lymph nodes was observed more frequently in maspin-negative cases than in tumors with more than 5% of positive cells (P = 0.0024). The present results confirm that maspin expression predicts a better prognosis in oral squamous cell carcinoma and that maspin probably plays a role in tumor progression.

Paradoxical expression of maspin in gastric carcinomas: correlation with carcinogenesis and progression

Maspin, a serine protease inhibitor related to the serpin family, can suppress invasion and metastasis of malignancies. To clarify the role of maspin in the genesis and progression of gastric carcinomas, its expression pattern and level were studied by immunohistochemistry on tissue microarrays containing gastric carcinoma (n = 237), normal gastric mucosa (n = 23), intestinal metaplasia (n = 38), and adenoma (n = 42); and the findings were compared with clinicopathological parameters. Furthermore, maspin expression in the gastric carcinoma cell lines (HCG-27, MKN28, and MKN45) was examined by immunohistochemistry and Western blotting. We found that cytoplasmic and nuclear maspin expression paralleled each other (P < .05) and decreased from intestinal metaplasia, adenoma, and carcinoma to normal gastric mucosa (P < .05). A significant positive association was noted with depth of invasion, lymphatic invasion, lymph node metastasis, and TNM stage (P < .05) but not with sex or Lauren's classification (P > .05). Univariate and multivariate analyses indicated that expression of maspin correlated negatively with cumulative patient survival in gastric carcinoma (P < .05) but was not an independent factor in the prognosis. The 2 independent factors, depth of invasion and lymphatic invasion, influenced the relation between nuclear maspin expression and survival, whereas only depth of invasion correlated with cytoplasmic maspin. Our study indicated that maspin expression experiences upregulation in gastric precancerous lesions and then slight downregulation with malignant transformation. High expression may paradoxically promote invasion and metastasis of gastric carcinomas and could be considered a good marker for the pathobiological behaviors of gastric carcinomas.

Aberrant maspin expression in human endometrial cancer

Maspin, a mammary serine protease inhibitor, was originally reported as a tumor suppressor gene in breast cancer. The purpose of the present study was to examine maspin expression and evaluate its clinicopathological significance in endometrial cancer. We examined maspin expression immunohistochemically in 41 cases with endometrioid adenocarcinoma. DNA methylation status at the maspin promoter region was determined by the methylation-specific polymerase chain reaction method. Aberrant maspin expression was observed in 27 (66%) of 41 endometrioid adenocarcinomas but not in normal endometrial glands. Maspin immunoreactivity of the tumor cells varied in incidence and density among tumors. Positive staining was correlated significantly with the presence of squamous differentiation (presence vs absence = 11/11 [100%] vs 16/30 [53%], P < 0.05), and nuclear subcellular localization of maspin protein was also significantly associated with squamous differentiation (nuclear positive vs nuclear negative = 6/11 [54%] vs 2/30 [6.7%], P < 0.05). An inverse correlation between their immunoreactivity and methylation status was observed (P < 0.01). Three of the four cell lines established from endometrioid adenocarcinomas overexpressed maspin mRNA and its protein product. In a maspin-negative cell line, maspin expression was induced by treatment with 5-aza-2'-deoxycytidine, a DNA demethylating agent. There was no significant correlation between maspin expression and any clinicopathlogical data. These findings suggest that maspin induced by DNA demethylation at the promoter region may contribute to squamous differentiation of tumor cells in endometrioid adenocarcinomas.