High expression of stathmin protein predicts a fulminant course in medulloblastoma

The effect of downregulation of Stathmin gene on biological behaviors of U373 and U87-MG glioblastoma cells

Background

Stathmin as a critical protein involved in microtubule polymerization, is necessary for survival of cancer cells. However, extremely little is known about Stathmin in glioblastoma. So, this study was designed to elucidate the function of Stathmin gene in the tumorigenesis and progression of glioblastoma cells.

Method

The lentiviral interference vector pLV3-si-Stathmin targeting Stathmin gene and the control vector pLV3-NC were established for the co-transfection of 293T cells together with the helper plasmids. Viral titer was determined via limiting dilution assay. Then pLV3-si-Stathmin and pLV3-NC were stably co-transfected into U373 and U87-MG glioblastoma cells. Expression levels of Stathmin protein in each group were determined by using Western Blot, and the proliferation and migration ability of the cells with downregulated Stathmin were evaluated through CCK8 assay and transwell invasion assay, respectively. Cell cycles and cell apoptosis were detected with flow cytometry. Finally, the effect of Stathmin in tumor formation was determined in nude mice.

Result

DNA sequencing and viral titer assay indicated that the lentiviral interference vector was successfully established with a viral titer of 4 × 10⁸ TU/ml. According to the results from Western Blotting, Stathmin protein expression level decreased significantly in the U373 and U87-MG cells after transfected with pLV3-si-Stathmin, respectively, compared with those transfected with pLV3-NC. In glioblastoma cells, the cell proliferation and migration were greatly inhibited after the downregulation of Stathmin protein. Flow cytometry showed that much more cells were arrested in G2/M phasein Stathmin downregulated group, compared with the non-transfection group and NC group. But Stathmin downregulation did not induce significant cell apoptosis. Tumor formation assay in nude mice showed that tumor formation was delayed after Stathmin downregulation, with a reduction in both tumor formation rate and tumor growth velocity.

Conclusion

Stathmin downregulation affected the biological behaviors of U373 and U87-MG glioblastoma cells, inhibiting the proliferation and migration of tumor cells. Stathmin gene may serve as a potential target in gene therapy for glioblastoma.

Siva 1 inhibits proliferation, migration and invasion by phosphorylating Stathmin in ovarian cancer cells

Ovarian cancer is one of the most common types of gynecologic malignant tumor, with high incidence and high mortality rates. It is difficult to diagnose ovarian cancer early due to the complex structure and function of the ovaries. Siva 1 is a well-known pro-apoptosis protein that functions in multiple types of cancer cells: There are several studies demonstrating that Siva 1 arrests apoptosis and facilitates cancer development in osteosarcoma and non-small cell lung cancer. Whether Siva 1 functions in ovarian cancer remains unknown. In the present study, it was established that Siva 1 was stably overexpressed in ovarian cancer cell lines, and demonstrated that the overexpression of Siva 1 inhibited proliferation, promoted apoptosis and suppressed migration and invasion by facilitating phosphorylation of Stathmin and polymerization of α-tubulin in ovarian cancer cells. These data provide specific novel insights into the molecular mechanism of ovarian cancer, and may be of significance for the clinical diagnosis and therapy of ovarian cancer.

PIWIL1 destabilizes microtubule by suppressing phosphorylation at Ser16 and RLIM-mediated degradation of Stathmin1

Human PIWIL1, alias HIWI, is a member of Piwi protein family and expressed in various tumors. However, the underlying mechanism of PIWIL1 in tumorigenesis remains largely unknown. Stathmin1 is a cytosolic phosphoprotein which has a critical role in regulating microtubule dynamics and is overexpressed in many cancers. Here we report that PIWIL1 can directly bind to Stathmin1. Meanwhile, PIWIL1 can up-regulate the expression of Stathmin1 through inhibiting ubiquitin-mediated degradation induced by an E3 ubiquitin ligase RLIM. Furthermore, PIWIL1 can also reduce phosphorylation level of Stathmin1 at Ser-16 through inhibiting the interaction between CaMKII and Stathmin1. Our results showed that PIWIL1 suppresses microtubule polymerization, and promotes cell proliferation and migration via Stathmin1 for the first time. Our study reveals a novel mechanism for PIWIL1 in tumorigenesis.

Emerging microtubule targets in glioma therapy

Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.

Effectiveness of local injection of lentivirus-delivered stathmin1 and stathmin1 shRNA in human gastric cancer xenograft mouse

BACKGROUND AND AIM

We have reported previously that RNA interference targeting stathmin1 (STMN1) gene in human gastric cancer cells inhibits proliferation in vitro and tumor growth in vivo. Based on these observations, in the present study, the possibility that local injection of lentivirus-delivered stathmin shRNA would induce regression of the established human gastric cancer xenograft in animal model was investigated.

METHODS

BALB/c nude mice were inoculated subcutaneously into the right armpit with human gastric cancer cells SGC-7901(2 × 10(6) cells in 200 μL phosphate-buffered saline) to develop a xenograft model of human gastric cancer. When tumor reached suitable size, mice were randomly divided into two groups. STMN1 shRNA group (n = 6) were given local injection of lentivirus-delivered STMN1 shRNA, and the non-silencing shRNA group (n = 6) were administered with local injection of lentivirus-delivered non-silencing shRNA. Quantitative reverse transcription-polymerase chain reaction and Western blot were used to verify the knockdown of the gene expression in dissected tumor at mRNA and protein level, respectively.

RESULTS

Experimental therapy on the nude mice model bearing subcutaneous tumor of SGC-7901 cells showed that local administration of STMN1 shRNA effectively regressed the pre-established tumors. Stathmin shRNA-treated tumors were significantly regressed as compared with that of the tumor injected with non-silencing shRNA (P < 0.05). Tumor weight was significantly decreased in STMN1-treated group as compared with non-silencing shRNA group (P < 0.05). Quantitative reverse transcription-polymerase chain reaction and Western blot showed downregulation of STMN1 gene expression in STMN1 shRNA group as compared with non-silencing shRNA group (P < 0.05).

CONCLUSION

These findings highlight the potential use of local injection of lentivirus-delivered shRNA for the treatment of early localized human gastric carcinoma.

Stathmin destabilizing microtubule dynamics promotes malignant potential in cancer cells by epithelial-mesenchymal transition

BACKGROUND

Stathmin is a ubiquitous cytosolic regulatory phosphoprotein and is overexpressed in different human malignancies. The main physiological function of stathmin is to interfere with microtubule dynamics by promoting depolymerization of microtubules or by preventing polymerization of tubulin heterodimers. Stathmin plays important roles in regulating many cellular functions as a result of its microtubule-destabilizing activity. Currently, the critical roles of stathmin in cancer cells, as well as in lymphocytes have been valued. This review discusses stathmin and microtubule dynamics in cancer development, and hypothesizes their possible relationship with epithelial-mesenchymal transition (EMT).

DATA SOURCES

A PubMed search using such terms as "stathmin", "microtubule dynamics", "epithelial-mesenchymal transition", "EMT", "malignant potential" and "cancer" was performed to identify relevant studies published in English. More than 100 related articles were reviewed.

RESULTS

The literature clearly documented the relationship between stathmin and its microtubule-destabilizing activity of cancer development. However, the particular mechanism is poorly understood. Microtubule disruption is essential for EMT, which is a crucial process during cancer development. As a microtubule-destabilizing protein, stathmin may promote malignant potential in cancer cells by initiating EMT.

CONCLUSIONS

We propose that there is a stathmin-microtubule dynamics-EMT (S-M-E) axis during cancer development. By this axis, stathmin together with its microtubule-destabilizing activity contributes to EMT, which stimulates the malignant potential in cancer cells.

Movers and shakers: cell cytoskeleton in cancer metastasis

Metastasis is responsible for the greatest number of cancer deaths. Metastatic disease, or the movement of cancer cells from one site to another, is a complex process requiring dramatic remodelling of the cell cytoskeleton. The various components of the cytoskeleton, actin (microfilaments), microtubules (MTs) and intermediate filaments, are highly integrated and their functions are well orchestrated in normal cells. In contrast, mutations and abnormal expression of cytoskeletal and cytoskeletal-associated proteins play an important role in the ability of cancer cells to resist chemotherapy and metastasize. Studies on the role of actin and its interacting partners have highlighted key signalling pathways, such as the Rho GTPases, and downstream effector proteins that, through the cytoskeleton, mediate tumour cell migration, invasion and metastasis. An emerging role for MTs in tumour cell metastasis is being unravelled and there is increasing interest in the crosstalk between key MT interacting proteins and the actin cytoskeleton, which may provide novel treatment avenues for metastatic disease. Improved understanding of how the cytoskeleton and its interacting partners influence tumour cell migration and metastasis has led to the development of novel therapeutics against aggressive and metastatic disease.

LINKED ARTICLES

This article is part of a themed section on Cytoskeleton, Extracellular Matrix, Cell Migration, Wound Healing and Related Topics. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-24.

Stathmin overexpression identifies high risk for lymphatic metastatic recurrence in pN0 esophageal squamous cell carcinoma patients

BACKGROUND AND AIM

Common patterns of the operative failure after Ivor-Lewis esophagectomy in esophageal squamous cell carcinoma (ESCC) patients are locoregional lymph node metastasis. It is clinically significant to investigate the biological markers to predict the subset of patients who are at higher risk of lymphatic metastatic recurrence. Our research aimed to investigate the association between the Stathmin (STMN-1) gene expression and lymphatic metastatic recurrence in pN0 ESCC patients after surgery.

METHODS

One hundred seventy-four patients who suffered from mid-thoracic ESCC and completely resected with Ivor-Lewis esophagectomy were enrolled in our study. The entire patients were restricted to pN0 ESCC. Tissue specimens were examined for STMN-1 expression levels by immunohistochemistry and Western blotting methods. The correlation of STMN-1 levels with clinicopathological variables, prognosis, and metastatic potential was analyzed.

RESULTS

One hundred patients had STMN-1 protein overexpression (57.47%), and the patients with overexpression were accompanied by significantly higher rate of lymphatic metastatic recurrence as compared with patients who had low STMN-1 expression (P = 0.003). Multivariable Cox regression analysis revealed that the STMN-1 protein expression and T classification were independent factors to predict the lymphatic metastatic recurrence (P = 0.007, P = 0.000, respectively).

CONCLUSIONS

Even pN0 ESCC are a potential to lymphatic metastatic recurrence. Stathmin overexpression can be used as a marker to identify those patients who are at high risk for lymphatic metastatic recurrence in pN0 ESCC after an Ivor-Lewis esophagectomy.

STMN-1 is a potential marker of lymph node metastasis in distal esophageal adenocarcinomas and silencing its expression can reverse malignant phenotype of tumor cells

BACKGROUND

Distal esophageal adenocarcinoma is a highly aggressive neoplasm. Despite advances in diagnosis and therapy, the prognosis is still poor. Stathmin (STMN-1) is a ubiquitously expressed microtubule destabilizing phosphoprotein. It promotes the disassembly of microtubules and prevents assembly. STMN-1 can cause uncontrolled cell proliferation when mutated and not functioning properly. Recently, found to be overexpressed in many types of human cancers. However, its clinical significance remains elusive in distal esophageal adenocarcinoma. Here, we reported for the first time that STMN-1 is highly overexpressed in adenocarcinomas of the distal esophagus and strongly associated with lymph node metastasis.

METHODS

STMN-1 expression in 63 cases of distal esophageal adenocarcinoma was analyzed by immunoblotting, while expression in esophageal adenocarcinoma cells was determined by immunocytochemistry, immunofluorescence, qRT-PCR and western blotting. Lentivirus-mediated RNAi was employed to knock-down STMN-1 expression in Human esophageal adenocarcinoma cells. The relationship between STMN-1 expression and lymph node metastasis in distal esophageal adenocarcinoma was determined by univariate and multivariate analyses.

RESULTS

STMN-1 was detected in 31 (49.21%) of the 63 cases. STMN-1 was highly overexpressed in specimens with lymph node metastasis pN (+), but its expression was almost undetected in pN (-) status. Multivarian regression analysis demonstrated that STMN-1 overexpression is an independent factor for lymph node metastasis in distal esophageal adenocarcinoma. STMN-1 shRNA effectively reduced STMN-1 expression in esophageal adenocarcinoma cells (P < 0.05), which significantly suppressed proliferation (P < 0.05), increased migration (P < 0.05) and invasion ability (P < 0.05) and G1 phase arrest (P < 0.05) which lead to induction of apoptosis in esophageal adenocarcinoma cells in vitro. To verify the in vitro data, we conducted in vivo tumor xenograft studies. Esophageal adenocarcinoma cells stably transfected with STMN-1 shRNA significantly reduced tumor xenografts volume in vivo.

CONCLUSIONS

STMN-1 overexpression is associated with lymph node metastasis and increase malignancy in distal esophageal adenocarcinoma. In vivo and in vitro laboratory findings, suggests that STMN-1 may be a suitable target for future therapeutic strategies in distal esophageal adenocarcinoma.

Lentiviral-mediated RNA interference targeting stathmin1 gene in human gastric cancer cells inhibits proliferation in vitro and tumor growth in vivo

BACKGROUND

Gastric cancer is highly aggressive disease. Despite advances in diagnosis and therapy, the prognosis is still poor. Various genetic and molecular alterations are found in gastric cancer that underlies the malignant transformation of gastric mucosa during the multistep process of gastric cancer pathogenesis. The detailed mechanism of the gastric cancer development remains uncertain. In present study we investigated the potential role of stathmin1 gene in gastric cancer tumorigenesis and examined the usefulness of RNA interference (RNAi) targeting stathmin1 as a form of gastric cancer treatment.

METHODS

A lentiviral vector encoding a short hairpin RNA (shRNA) targeted against stathmin1 was constructed and transfected into the packaging cells HEK 293 T and the viral supernatant was collected to transfect MKN-45 cells. The transwell chemotaxis assay and the CCK-8 assay were used to measure migration and proliferation of tumor cells, respectively. Quantitative real-time PCR and western blotting were used to detect the expression levels of stathmin1.

RESULTS

Lentivirus mediated RNAi effectively reduced stathmin1 expression in gastric cells. Significant decreases in stathmin1 mRNA and protein expression were detected in gastric cells carrying lentiviral stathmin-shRNA vector and also significantly inhibited the proliferation, migration in gastric cancer cells and tumorigenicity in Xenograft Animal Models.

CONCLUSIONS

Our findings suggest that stathmin1 overexpression is common in gastric cancer and may play a role in its pathogenesis. Lentivirus mediated RNAi effectively reduced stathmin1 expression in gastric cells. In summary, shRNA targeting of stathmin1 can effectively inhibits human gastric cancer cell growth in vivo and may be a potential therapeutic strategy for gastric cancer.

Medullospheres from DAOY, UW228 and ONS-76 cells: increased stem cell population and proteomic modifications

Background

Medulloblastoma (MB) is an aggressive pediatric tumor of the Central Nervous System (CNS) usually treated according to a refined risk stratification. The study of cancer stem cells (CSC) in MB is a promising approach aimed at finding new treatment strategies.

Methodology/Principal Findings

The CSC compartment was studied in three characterized MB cell lines (DAOY, UW228 and ONS-76) grown in standard adhesion as well as being grown as spheres, which enables expansion of the CSC population. MB cell lines, grown in adherence and as spheres, were subjected to morphologic analysis at the light and electron microscopic level, as well as cytofluorimetric determinations. Medullospheres (MBS) were shown to express increasingly immature features, along with the stem cells markers: CD133, Nestin and β-catenin. Proteomic analysis highlighted the differences between MB cell lines, demonstrating a unique protein profile for each cell line, and minor differences when grown as spheres. In MBS, MALDI-TOF also identified some proteins, that have been linked to tumor progression and resistance, such as Nucleophosmin (NPM). In addition, immunocytochemistry detected Sox-2 as a stemness marker of MBS, as well as confirming high NPM expression.

Conclusions/Significance

Culture conditioning based on low attachment flasks and specialized medium may provide new data on the staminal compartment of CNS tumors, although a proteomic profile of CSC is still elusive for MB.

Expression and phosphorylation of stathmin correlate with cell migration in esophageal squamous cell carcinoma

Microtubules play extensive roles in cellular processes, including cell motility. Stathmin is an important protein which destabilizes microtubules. The essential function of stathmin is closely associated with its phosphorylation status. Stathmin is overexpressed in many human cancers and has a significant relationship with clinical characteristics such as grade, tumor size and prognosis. We demonstrated that stathmin was overexpressed in ESCC tissues using both 2-DE and immunohistochemistry analysis. In addition, overexpression of stathmin was significantly correlated with histological grade in ESCC. However, no correlation was found with age, gender and lymph node metastasis. Knockdown of stathmin with siRNA impaired cell migration in KYSE30 and KYSE410 cells. When EC0156 cells were treated with paclitaxel, stathmin was stably phosphorylated and migration was impaired. These observations suggest that stathmin may have a more important function in ESCC development and migration. The present study provides further understanding of the importance of stathmin in ESCC therapy or diagnosis.

Analysis of different medulloblastoma histotypes by two-dimensional gel and MALDI-TOF

OBJECTIVE

The purpose of this study is to detect different protein profiles in medulloblastoma (MDB) that may be clinically relevant and to check the correspondence of histological classification of MDB with proteomic profiles.

MATERIALS AND METHODS

Surgical specimens, snap frozen at the time of neurosurgery, entered the proteomic study. Eight samples from patients (age range, 4 months-26 years) with different MDB histotypes (five classic, one desmoplastic/nodular, one with extensive nodularity, and one anaplastic) were analyzed by two-dimensional gel electrophoresis. One sample for each histotype was further characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis.

RESULTS

Eighty-six unique proteins were identified and compared to histology, with the determination of proteins expressed by single histotypes and of a smaller number of proteins shared by two or three histotypes. The sharp difference of protein expression was found to be in agreement with WHO histological classification, with the identification of type-specific proteins with limited overlapping between histotypes.

CONCLUSION

Proteomic analysis confirmed and strengthened the difference between histotypes as biologically relevant. Cluster analysis enhanced the distance of extensive nodularity MDB from other histotypes. Possible innovative approaches to therapy may rely upon a proteomic-based classification of MDB tightly correlated to histology. The utility of snap freezing tumoral samples must be stressed and should become a mandatory task for pathologists.

Stathmin: a protein with many tasks. New biomarker and potential target in cancer

INTRODUCTION

Stathmin is a microtubule-destabilizing phosphoprotein, firstly identified as the downstream target of many signal transduction pathways. Several studies then indicated that stathmin is overexpressed in many types of human malignancies, thus deserving the name of Oncoprotein 18 (Op18). At molecular level, stathmin depolymerizes microtubules by either sequestering free tubulin dimers or directly inducing microtubule-catastrophe. A crucial role for stathmin in the control of mitosis has been proposed, since both its overexpression and its downregulation induce failure in the correct completion of cell division. Accordingly, stathmin is an important target of the main regulator of M phase, cyclin-dependent kinase 1.

AREAS COVERED

Recent evidences support a role for stathmin in the regulation of cell growth and motility, both in vitro and in vivo, and indicate its involvement in advanced, invasive and metastatic cancer more than in primary tumors.

EXPERT OPINION

Many studies suggest that high stathmin expression levels in cancer negatively influence the response to microtubule-targeting drugs. These notions together with the fact that stathmin is expressed at very low levels in most adult tissues strongly support the use of stathmin as marker of prognosis and as target for novel anti-tumoral and anti-metastatic therapies.

Stathmin overexpression identifies high-risk patients and lymph node metastasis in endometrial cancer

PURPOSE

Overexpression of the oncogen Stathmin has been linked to aggressive endometrial carcinoma and a potential for PI3Kinase inhibitors in this disease. We wanted to validate the prognostic value of Stathmin expression in a large prospective multicenter setting. As lymph node sampling is part of current surgical staging, we also aimed to test if Stathmin expression in endometrial curettage specimens could predict lymph node metastasis.

EXPERIMENTAL DESIGN

A total of 1,076 endometrial cancer patients have been recruited from 10 centers to investigate the biological tumor marker Stathmin in relation to clinicopathologic variables, including lymph node status and survival. Stathmin immunohistochemical staining was carried out in 477 hysterectomy and 818 curettage specimens.

RESULTS

Seventy-one percent of the patients (n = 763) were subjected to lymph node sampling, of which 12% had metastatic nodes (n = 94). Overexpression of Stathmin was detected in 37% (302 of 818) of the curettage and in 18% (84 of 477) of the hysterectomy specimens investigated. Stathmin overexpression in curettage and hysterectomy specimens were highly correlated and significantly associated with nonendometrioid histology, high grade, and aneuploidy. Stathmin analysis in preoperative curettage samples significantly correlated with, and was an independent predictor of, lymph node metastases. High Stathmin expression was associated with poor disease-specific survival (P ≤ 0.002) both in curettage and hysterectomy specimens.

CONCLUSIONS

Stathmin immunohistochemical staining identifies endometrial carcinomas with lymph node metastases and poor survival. The value, as a predictive marker for response to PI3Kinase inhibition and as a tool to stratify patients for lymph node sampling in endometrial carcinomas, remains to be determined.

Stathmin1 overexpression associated with polyploidy, tumor-cell invasion, early recurrence, and poor prognosis in human hepatoma

Frequent intrahepatic metastasis causes early tumor recurrence and dismaying prognosis of human hepatocellular carcinoma (HCC). We recently identified overexpression of stathmin1 (STMN1) in human HCC. This study was designed to elucidate the clinical and biological significance of overexpression of STMN1 in HCC. Expression of STMN1 was conducted by quantitative reverse transcription-polymerase chain reaction and immunoblotting assays on 58 pairs of HCC and para-tumor liver tissues from patients with HCC along with normal liver tissues as the controls. Association of STMN1 overexpression with tumor recurrence and prognosis was investigated by Kaplan-Meier cumulative survival and Cox Regression analyses. Roles of STMN1 in cell cycle, cell motility, and invasion were determined by in vitro assays. STMN1 overexpression in hepatoma was strongly associated with local invasion (P = 0.031), early recurrence (P = 0.002), and poor prognosis (P = 0.005), and was an independent indicator for tumor recurrence (P = 0.0045). STMN1 overexpression further identified subgroups of HCC patients with higher tumor recurrence and worse prognosis among HCC patients with early tumor stage (T1) or intermediate histological grades (G2 and G3), both of whom represent the majority of HCC patients receiving primary curative hepatectomy. Silencing STMN1 expression via RNA interference suppressed invasion activity, while ectopic expression of STMN1 enhanced cell invasion and caused polyploidy of cells. In conclusion, STMN1 overexpression could predict early tumor recurrence and poor prognosis, particularly at early stage of hepatoma. Overexpression of STMN1 promoted polyploidy formation, tumor-cell invasion, and intrahepatic metastasis, suggesting that STMN1 can be a target for anti-cancer therapy of human hepatoma.

Significance of STMN1 expression in esophageal squamous cell carcinoma

AIM: To investigate the expression of Stathmin 1 (STMN1) protein in esophageal squamous cell carcinoma (ESCC) tissue and cell lines and to evaluate its correlation with the clinicopathologic parameters of ESCC.

METHODS: One-dimensional (1-D) Western blot was performed to determine the expression of STMN1 in 8 ESCC cell lines. Two-dimensional (2-D) Western blot was used to determine modified STMN1 in KYSE180 cells. Western blot and immunohistochemistry (IHC) were employed to determine the expression of STMN1 in ESCC specimens. The chi-square test was used to analyze IHC results.

RESULTS: STMN1 was widely expressed in ESCC cells, including WHCO1, EC0156, KYSE510, KYSE180, KYSE170, KYSE150, KYSE140 and KYSE30 cell lines. Two STMN1 protein spots were detected in KYSE180 cells on 2-D Western blot: one stronger signal and one weaker signal located in more basic area, which suggests that STMN1 protein may be modified in KYSE180 cells. Western blot analysis showed that STMN1 was overexpressed in 69.2% (9/13) of ESCC specimens compared with their normal epithelial counterparts. IHC assay also demonstrated that the positive rate of STMN1 expression was significantly higher in ESCC tissue than in matched adjacent normal tissue (P < 0.05). STMN1 expression is not correlated with age, gender, differentiation, tumor grade and lymph node metastasis.

CONCLUSION: The expression of STMN1 protein is up-regulated in both ESCC tissue and cell lines and may be modified in some ESCC cell lines. STMN1 might exert an oncogenic function in ESCC. Dynamic measurement of STMN1 expression level might aid to evaluate the progression of ESCC.