Loss of maspin is a negative prognostic factor for invasion and metastasis in oral squamous cell carcinoma

A meta‑ and bioinformatics analysis of maspin expression levels influencing the prognosis of patients with breast cancer

Maspin is a serine protease inhibitor that is encoded by the human SERPINB5 gene. As a tumor inhibitor, it can inhibit the growth of tumor cells, increase adhesion between tumor cells and inhibit tumor angiogenesis. In the present study, a meta- and bioinformatics analysis was performed through the PubMed and China National Knowledge Infrastructure databases including entries added until up to March 20, 2023. It was found that compared with normal breast tissue, maspin expression was downregulated in breast cancer tissue. Maspin expression was negatively associated with lymph node metastasis. According to Kaplan-Meier plotter, it was found that lower maspin expression was negatively associated with the overall and distant metastasis-free survival rate of patients with estrogen receptor-positive, luminal A and grade 2 breast cancer. High expression of maspin was also positively associated with the relapse-free survival rate of patients of the luminal A subtype. Low maspin expression was positively associated with the post-progression and distant metastasis-free survival rate of the progesterone receptor-negative subtype. According to the GEPIA database, SERPINB5 mRNA expression was higher in normal than breast cancer tissues and negatively correlated with the TNM stage. High expression of maspin was also positively associated with the overall survival rate. In the UALCAN database, it was found that the mRNA and promoter methylation levels of SERPINB5 were higher in normal than in breast cancer tissues. These findings suggest that the expression of maspin may serve as a potential marker to indicate the occurrence, subsequent progression and even prognosis of breast cancer.

Automatic discrimination of Yamamoto-Kohama classification by machine learning approach for invasive pattern of oral squamous cell carcinoma using digital microscopic images: a retrospective study

OBJECTIVE

The Yamamoto-Kohama criteria are clinically useful for determining the mode of tumor invasion, especially in Japan. However, this evaluation method is based on subjective visual findings and has led to significant differences in determinations between evaluators and facilities. In this retrospective study, we aimed to develop an automatic method of determining the mode of invasion based on the processing of digital medical images.

STUDY DESIGN

Using 101 digitized photographic images of anonymized stained specimen slides, we created a classifier that allowed clinicians to introduce feature values and subjected the cases to machine learning using a random forest approach. We then compared the Yamamoto-Kohama grades (1, 2, 3, 4C, 4D) determined by a human oral and maxillofacial surgeon with those determined using the machine learning approach.

RESULTS

The input of multiple test images into the newly created classifier yielded an overall F-measure value of 87% (grade 1, 93%; grade 2, 67%; grade 3, 89%; grade 4C, 83%; grade 4D, 94%). These results suggest that the output of the classifier was very similar to the judgments of the clinician.

CONCLUSIONS

This system may be valuable for diagnostic support to provide an accurate determination of the mode of invasion.

Addiction of mesenchymal phenotypes on the FGF/FGFR axis in oral squamous cell carcinoma cells

The epithelial–mesenchymal transition (EMT) is a crucial morphological event that occurs during epithelial tumor progression. ZEB1/2 are EMT transcription factors that are positively correlated with EMT phenotypes and breast cancer aggressiveness. ZEB1/2 regulate the alternative splicing and hence isoform switching of fibroblast growth factor receptors (FGFRs) by repressing the epithelial splicing regulatory proteins, ESRP1 and ESRP2. Here, we show that the mesenchymal-like phenotypes of oral squamous cell carcinoma (OSCC) cells are dependent on autocrine FGF–FGFR signaling. Mesenchymal-like OSCC cells express low levels of ESRP1/2 and high levels of ZEB1/2, resulting in constitutive expression of the IIIc-isoform of FGFR, FGFR(IIIc). By contrast, epithelial-like OSCC cells showed opposite expression profiles for these proteins and constitutive expression of the IIIb-isoform of FGFR2, FGFR2(IIIb). Importantly, ERK1/2 was constitutively phosphorylated through FGFR1(IIIc), which was activated by factors secreted autonomously by mesenchymal-like OSCC cells and involved in sustained high-level expression of ZEB1. Antagonizing FGFR1 with either inhibitors or siRNAs considerably repressed ZEB1 expression and restored epithelial-like traits. Therefore, autocrine FGF–FGFR(IIIc) signaling appears to be responsible for sustaining ZEB1/2 at high levels and the EMT phenotype in OSCC cells.

Predictive Value of Maspin and Ki-67 Expression in Transurethral Resection Specimens in Patients with T1 Bladder Cancer

Aims and background

To evaluate the clinical significance of maspin and Ki-67 expression in patients with newly diagnosed T1 bladder cancer.

Methods and study design

Maspin and Ki-67 expression was investigated by immunohistochemistry from paraffin-embedded tissues of 68 patients undergoing transurethral resection for bladder cancer. Clinicopathological data were retrospectively reviewed from available charts and pathological reports. Maspin and Ki-67 expression levels were classified according to the staining percentage. Cases in which at least 5% of the tumor cells stained for maspin were scored as positive. Ki-67 labeling index was considered to be positive when samples demonstrated >10% reactivity.

Results

Maspin expression was found as an independent predictor of recurrence and progression (P <0.05). Patients with negative maspin expression were 2.191 times more likely to relapse than patients with positive maspin expression. Patients with negative maspin expression were 4.345 times more likely to progress than patients with positive maspin expression. Furthermore, the maspin-negative group was found to have shorter recurrence and progression-free survival (P <0.05). No significant association was found between maspin subcellular localization pattern and recurrence-free, progression-free or overall survival (P >0.05). There was no correlation between Ki-67 expression and tumor recurrence, progression or tumor-related death (P >0.05). Chi-square tests showed a significant relationship between Ki-67 expression and tumor size and tumor grade (P <0.05).

Conclusions

Our findings suggested that the evaluation of maspin expression in stage T1 bladder tumors is a useful prognostic marker for predicting the tumor behavior.

The roles of maspin expression in gastric cancer: a meta- and bioinformatics analysis

Maspin is a mammary serine protease inhibitor that is encoded by human SERPINB5 gene, and inhibits invasion and metastasis of cancer cells as a tumor suppressor. We performed a systematic meta- and bioinformatics analysis through multiple online databases up to Feb 10, 2017. We found down-regulated maspin expression in gastric cancer, compared with normal mucosa and dysplasia (p < 0.05). Maspin expression was negatively correlated with depth of invasion, TNM staging and dedifferentiation of gastric cancer (p < 0.05). Nuclear maspin expression was higher in intestinal- than diffuse-type carcinoma (p < 0.05). An inverse association between maspin expression and unfavorable overall survival was found in patients with gastric cancer (p < 0.005). According to bioinformatics databases, SERPINB5 mRNA expression was higher in gastric cancer than normal tissues (p < 0.05), and negatively correlated with depth of invasion, TNM staging and dedifferentiation of gastric cancer (p < 0.05). According to KM plotter, we found that a higher SERPINB5 expression was positively correlated with overall and progression-free survival rates of all cancer patients, even stratified by aggressive parameters (p < 0.05). These findings indicated that maspin expression might be employed as a potential marker to indicate gastric carcinogenesis, subsequent progression, and even prognosis.

Combinations of SERPINB5 gene polymorphisms and environmental factors are associated with oral cancer risks

Background

We identified rs17071138 T/C, rs3744941 C/T, and rs8089104 T/C gene polymorphisms of SERPINB5 (mammary serine protease inhibitor) that are specific to patients with oral cancer susceptibility and their clinicopathological status.

Methodology/Principal findings

In total, 1342 participants, including 601 healthy controls and 741 patients with oral cancer, were recruited for this study. Allelic discrimination of rs17071138 T/C, rs3744941 C/T, and rs8089104 T/C of the SERPINB5 gene was assessed by a real-time PCR with a TaqMan assay. We found that individuals carrying the polymorphic rs17071138 and rs8089104 are more susceptible to oral cancer (OR, 1.57; 95% CI, 1.07~2.31 and OR, 1.58; 95% CI, 1.04~2.39, respectively). Among oral cancer-related risk factor exposures, the individuals carrying the polymorphic rs17071138 had 4.26- (95% CI: 1.65~11.01; p = 0.002), 2.34- (95% CI: 1.19~4.61; p = 0.01), and 2.34-fold (95% CI: 1.38~3.96; p = 0.001) higher risks of developing oral cancer.

Conclusions

Heterozygous TC of the SERPINB5 rs17071138 polymorphism may be a factor that increases susceptibility to oral cancer. Interactions of gene-to-gene and gene-to-oral cancer-related environmental risk factors have a synergetic effect that can further enhance oral cancer development.

Impact of Maspin Polymorphism rs2289520 G/C and Its Interaction with Gene to Gene, Alcohol Consumption Increase Susceptibility to Oral Cancer Occurrence

BACKGROUND

The purpose of this study was to identify gene polymorphisms of mammary serine protease inhibitor (Maspin) specific to patients with oral cancer susceptibility and clinicopathological status.

METHODOLOGY/PRINCIPAL FINDINGS

Three single-nucleotide polymorphisms (SNPs) of the Maspin gene from 741 patients with oral cancer and 601 non-cancer controls were analyzed by real-time PCR. The participants with G/G homozygotes or with G/C heterozygotes of Maspin rs2289520 polymorphism had a 2.07-fold (p = 0.01) and a 2.01-fold (p = 0.02) risk of developing oral cancer compared to those with C/C homozygotes. Moreover, gene-gene interaction increased the risk of oral cancer susceptibility among subjects expose to oral cancer related risk factors, including areca, alcohol, and tobacco consumption.

CONCLUSION

G allele of Maspin rs2289520 polymorphism may be a factor that increases the susceptibility to oral cancer. The interactions of gene to oral cancer-related environmental risk factors have a synergetic effect that can further enhance oral cancer development.

Nuclear maspin expression as a predictive marker for fluorouracil treatment response in colon cancer

BACKGROUND

Maspin is a member of the serpin family of protease inhibitors whose function in colorectal cancer is not fully understood. The objective of this study was to determine whether level of maspin expression could have prognostic or predictive value in colorectal cancer.

MATERIAL AND METHODS

Maspin expression was assessed using immunohistochemistry on tissue microarrays obtained from 380 patients with stage II and III colorectal cancer randomized to adjuvant chemotherapy with fluorouracil and levamisole (5-FU/Lev) or to surgery only (control), with scores (0-300) based on presence (0-100) and intensity (0-3) of maspin expression. Associations with disease-free survival (DFS), cancer-specific survival (CSS) and prognostic factors were determined.

RESULTS

Maspin expression was predominantly nuclear and present in tumor tissue in 99% of the cases. No associations with clinicopathological factors were identified. In colon cancer patients receiving adjuvant chemotherapy, maspin expression level was significantly associated with CSS [HR 1.43 per 50 points increase in maspin score (p = 0.021)] in multivariate analyses, and a significant interaction between treatment status and maspin expression (p = 0.045) was found. Kaplan-Meier plots from colon cancer patients showed a significant treatment benefit in patients with low maspin expression, but not for individuals with medium/high expression. Level of maspin expression was not significantly related to clinical outcome in rectal cancer or in any of the control groups.

CONCLUSIONS

In patients with colon cancer a low nuclear maspin expression was an independent predictor of benefit from adjuvant chemotherapy with 5-FU/Lev. A prognostic value of maspin expression was not found in this material.

HuD promotes progression of oral squamous cell carcinoma

Head and neck cancer, including oral squamous cell carcinoma (OSCC), ranks as the sixth most common malignancy worldwide. Overall 5-year survival rates of OSCC have not significantly improved during the past 3 decades and the 5-year survival rate is less than 50%. Several invasion grading systems have been employed in OSCC, however, their utility is still controversial. HuD belongs to the Hu protein family and acts as an RNA-binding protein involved in mRNA stability and translational regulation. Although HuD has a pivotal role for neuronal differentiation, the functional role of HuD in OSCCs is still unclear. In this study, we examined HuD expression in 82 OSCC cases. Expression of HuD was observed in 36.6% of OSCCs and significantly associated with histological differentiation, nodal metastasis and mode of invasion. HuD expression in high-metastatic HSC3 cells was higher than in low-metastatic HSC4 cells, and inhibition of invasion ability and activation of caspase-3 were shown by HuD siRNA-treated HSC3 cells. Furthermore, we clarified that HuD regulates expression of vascular endothelial growth factor (VEGF)-A, VEGF-D, matrix metallopeptidase (MMP)-2 and MMP-9. These results suggest that HuD is a useful diagnostic and therapeutic target in OSCCs.

Decreased maspin combined with elevated vascular endothelial growth factor C is associated with poor prognosis in non-small cell lung cancer

BACKGROUND

This study aimed to investigate the clinical significance of the combination of maspin and vascular endothelial growth factor (VEGF)-C expression in the prognosis of non-small cell lung cancer (NSCLC).

METHODS

Immunohistochemistry was performed to assay the expression of maspin and VEGF-C in primary tumor tissues, metastatic, and non-metastatic lymph nodes in 98 NSCLC patients. Survival analysis was determined by Kaplan-Meier curves.

RESULTS

The positive expression rate of maspin was 26.5% (26/98) in NSCLC primary tumor tissues, significantly associated with histological type (P = 0.005) and the absence of nodal metastasis (P < 0.001). The expression of maspin in primary tumor tissues was stronger than metastatic lymph nodes of the N1 group (P = 0.048), while the metastatic lymph nodes of the N1 group had a stronger maspin expression than the N2 group (P = 0.008). In survival analysis, a positive expression of maspin of the N1 lymph node was also found to be an independent positive prognostic factor in overall survival (P = 0.003). We also found that decreased maspin combined with elevated VEGF-C is associated with a poor prognosis for disease-free survival (P = 0.019).

CONCLUSION

Our results suggest that positive expression of maspin might significantly inhibit nodal metastasis in NSCLC. Decreased maspin combined with elevated VEGF-C might be associated with a poor prognosis in NSCLC.

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.

Expression of the tumour-suppressor maspin in temporal bone carcinoma

AIMS

Although it accounts for fewer than 0.2% of all head and neck tumours, temporal bone squamous cell carcinoma (SCC) is an aggressive malignancy with a poor prognosis in advanced cases. Novel therapeutic strategies should be developed focusing on specific targeted therapies. Maspin is a serpin showing tumour-suppressing activity which has therapeutic potential. The present study is the first to investigate maspin expression in temporal bone SCCs, using a series of 29 cases.

METHODS AND RESULTS

Cytoplasmic maspin expression was significantly higher in the group of patients whose SCC did not recur than in the group experiencing recurrences (P = 0.029), and in G1-G2 SCCs than in G3 cases (P = 0.001). cT correlated with recurrence rate (P = 0.05), disease-free survival (DFS) (P = 0.008) and disease-specific survival (DSS) (P = 0.0043), and pT and pathological regional lymph node status correlated with recurrence rate (P = 0.008 and P = 0.03, respectively), DFS (P = 0.017 and P = 0.0049, respectively) and DSS (P = 0.008 and P = 0.0009, respectively).

CONCLUSIONS

Although further studies using larger series are required, our preliminary findings suggest that cytoplasmic maspin expression has promise as a prognostic indicator of disease recurrence in temporal bone SCC, and that reactivating maspin functions in association with apoptosis-inducing or anti-angiogenic chemotherapeutic agents might be an important goal in the treatment of temporal bone SCC.

Elevated maspin expression is associated with better overall survival in esophageal squamous cell carcinoma (ESCC)

Tumor suppressor maspin is a differentially regulated gene in the progression of many types of cancer. While the biological function of maspin in blocking tumor invasion and metastasis is consistent with the loss of maspin expression at the late stage of tumor progression, the differential expression and the biological significance of maspin in early stage of tumor progression appear to be complex and remain to be elucidated. In the current study, we examined the expression of maspin in 84 esophageal squamous cell carcinoma (ESCC) cases (stages I–III) and 55 non-tumor adjacent esophageal tissue specimens by immunohistochemical (IHC) staining. The correlation of maspin with clinicopathological parameters was analyzed. Compared to normal esophageal squamous tissue where 80% (47/55) of the cases expressed maspin at a low to moderate level, all ESCC specimens (100% (84/84)) were positive for maspin expression at a moderate to high level. ESCC with low or moderate maspin expression had significantly shorter postoperative survival rates compared to those that had high maspin expression (p<0.001). Since the correlation of maspin with ESCC histology and the correlation of maspin with ESCC prognosis seem to be at odds, we further investigated the biological function of maspin in ESCC using the established ESCC cell lines. The expression of maspin in five human esophageal squamous cancer cell lines (T12, E450, KYSE150, EC109, and KYSE510) was examined by the Western blot. ESCC cell line KYSE510 that did not express maspin and was stably transfected by maspin cDNA or an empty vector. The resulting transfected cells were characterized in vitro. Maspin expression significantly inhibited cell proliferation, motility and matrigel invasion. Taken together, our data suggest that the transient up-regulation of maspin in the early development of ESCC may be a defense mechanism against further transition towards more malignant phenotypes, ultimately slowing down ESCC tumor progression.

Role of maspin in cancer

Maspin (mammary serine protease inhibitor), is a member of the serine protease inhibitor/non-inhibitor superfamily. Its expression is down-regulated in breast, prostate, gastric and melanoma cancers but over-expressed in pancreatic, gallbladder, colorectal, and thyroid cancers suggesting that maspin may play different activities in different cell types. However, maspin expression seems to be correlated with better prognosis in prostate, bladder, lung, gastric, colorectal, head and neck, thyroid and melanoma cancer. In breast and ovarian cancer maspin significance is associated with its subcellular localization: nucleus maspin expression correlates with a good prognosis, whilst in pancreatic cancer it predicts a poor prognosis. Since tumor metastasis requires the detachment and invasion of tumor cells through the basement membrane and stroma, a selectively increased adhesion by the presence of maspin may contribute to the inhibition of tumor metastasis. Furthermore the different position of maspin inside the cell or its epigenetic modifications may explain the different behavior of the expression of maspin between tumors. The expression of maspin might be useful as a prognostic and possibly predictive factor for patients with particular types of cancer and data can guide physicians in selecting therapy. Its expression in circulating tumor cells especially in breast cancer, could be also useful in clinical practice along with other factors, such as age, comorbidities, blood examinations in order to select the best therapy to be carried out. Focusing on the malignancies in which maspin showed a positive prognostic value, therapeutic approaches studied so far aimed to re-activate a dormant tumor suppressor gene by designed transcription factors, to hit the system that inhibits the expression of maspin, to identify natural substances that can determine the activation and the expression of maspin or possible “molecules binds” to introduce maspin in cancer cell and gene therapy capable of up-regulating the maspin in an attempt to reduce primarily the risk of metastasis.

Further studies in these directions are necessary to better define the therapeutic implication of maspin.

Loss of claudin-7 is a negative prognostic factor for invasion and metastasis in oral squamous cell carcinoma

Claudin-7 belongs to the claudin family, which consists of 24 subtypes of essential tight junction (TJ) integral membrane proteins with molecular weights of 20-27 kDa. We investigated the interrelationship between clinicopathological findings and claudin-7 expression in oral squamous cell carcinoma (OSCC). Using immunohistochemical techniques to examine the expression levels of claudin-7 in 67 cases of OSCC, claudin-7 expression was detected in 35 (52.2%) of the 67 cases. We also compared the clinicopathological features of the OSCC cases with claudin-7 expression levels. Moreover, six cell lines with various invasive properties were investigated in vitro to compare mRNA and protein levels of claudin-7 using reverse transcription-polymerase chain reaction (RT-PCR) and the western blotting method. Decreased claudin-7 expression correlated significantly with T-category (p<0.05), lymph node metastasis (p<0.01), and mode of invasion (p<0.001). Patients with positive claudin-7 expression had a significantly better prognosis (p<0.05). Claudin-7 protein and mRNA levels were lower in the HOC313 and TSU cells, which have higher invasive potentials compared with other cell lines. These results suggest that loss of claudin-7 expression is associated closely with invasion and lymph metastasis and is an unfavorable prognostic factor in patients with OSCC.

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.

Nuclear MASPIN expression relates to a better prognosis in elderly patients with laryngeal carcinoma

CONCLUSION

MASPIN subcellular location can be considered a prognostic marker that is potentially useful for identifying elderly patients with laryngeal carcinoma at higher risk of early loco-regional recurrence, who may benefit from more aggressive therapy. In a targeted treatment setting, re-activated nuclear MASPIN in combination with anti-angiogenic and/or cytotoxic drugs may be effective in treating laryngeal carcinoma in elderly patients.

OBJECTIVES

Aging is associated with molecular, cellular, and physiological changes that influence carcinogenesis and cancer growth. MASPIN has multifaceted anti-tumor effects and available evidence supports the hypothesis that its subcellular location influences its functions. The aim of the present study was to firstly assess the potential prognostic role of subcellular MASPIN location in elderly patients (>65 years old) with laryngeal carcinoma.

METHODS

MASPIN expression and location were immunohistochemically determined in 68 consecutive elderly patients with laryngeal carcinoma.

RESULTS

Nodal involvement and pathological stage correlated strongly with the prognosis for laryngeal carcinomas in elderly patients, in terms of disease recurrence rate and disease-free survival. The loco-regional recurrence rate was significantly lower (p = 0.041) and the disease-free survival after treatment was significantly longer (p = 0.045) in cases with a nuclear pattern of MASPIN subcellular expression.

Increased IKKα expression in the basal layer of the epidermis of transgenic mice enhances the malignant potential of skin tumors

Non-melanoma skin cancer is the most frequent type of cancer in humans. In this study we demonstrate that elevated IKKα expression in murine epidermis increases the malignancy potential of skin tumors. We describe the generation of transgenic mice overexpressing IKKα in the basal, proliferative layer of the epidermis and in the outer root sheath of hair follicles. The epidermis of K5-IKKα transgenic animals shows several alterations such as hyperproliferation, mislocalized expression of integrin-α6 and downregulation of the tumor suppressor maspin. Treatment of the back skin of mice with the mitogenic agent 12-O-tetradecanoylphorbol-13-acetate causes in transgenic mice the appearance of different preneoplastic changes such as epidermal atypia with loss of cell polarity and altered epidermal tissue architecture, while in wild type littermates this treatment only leads to the development of benign epidermal hyperplasia. Moreover, in skin carcinogenesis assays, transgenic mice carrying active Ha-ras (K5-IKKα-Tg.AC mice) develop invasive tumors, instead of the benign papillomas arising in wild type-Tg-AC mice also bearing an active Ha-ras. Therefore we provide evidence for a tumor promoter role of IKKα in skin cancer, similarly to what occurs in other neoplasias, including hepatocarcinomas and breast, prostate and colorectal cancer. The altered expression of cyclin D1, maspin and integrin-α6 in skin of transgenic mice provides, at least in part, the molecular bases for the increased malignant potential found in the K5-IKKα skin tumors.

Maspin modulates adhesion of bladder carcinoma cells to vascular endothelium

PURPOSE

Maspin belongs to the serpin family and has been shown to suppress tumor growth and metastasis in several tumor types. The role of maspin in bladder carcinoma has not been fully elucidated, and the object of this study was to investigate whether maspin contributes to bladder tumor adhesion to vascular endothelial cells (HUVEC).

METHODS

Expression of maspin-coding mRNA was evaluated in a panel of bladder carcinoma cell lines. Maspin distribution in maspin mRNA(high) versus maspin mRNA(low) cells was further analyzed by flow cytometry and confocal microscopy. Adhesion to HUVEC was measured in a coculture model and correlated with the surface-bound maspin.

RESULTS

Maspin(high) (RT-4, RT-112) cell lines strongly attached to HUVEC, whereas maspin(low) (UMUC-3, MGH-U1) cell lines poorly adhered to HUVEC. Distinct cytoplasmic maspin accumulation and moderate surface-bound maspin was found in RT-4 cells. Blocking maspin surface receptors prevented tumor cell attachment to HUVEC, indicating that surface-bound maspin is responsible for triggering cell adhesion. PMA-triggered elevation of surface-bound maspin was accompanied by an enhanced adhesion capacity of RT-4 cells, compared to controls. Finally, exposing the bladder carcinoma cells to the differentiation-inducing agent valproic acid led to a surface-bound (but not cytoplasmic) maspin decrease, paralleled by a significant reduction in tumor cell binding to HUVEC.

CONCLUSION

Surface-bound maspin directly controls bladder carcinoma cell adhesion to the vascular wall. Blocking this process may prevent transendothelial migration and tumor cell dissemination. Therefore, therapeutic down-regulation of surface-bound maspin might become an option to prevent tumor spread into distant organs.