Overexpression of stathmin 1 is associated with poor prognosis of patients with gastric cancer

A biomarker exploration in small-cell lung cancer for brain metastases risk and prophylactic cranial irradiation therapy efficacy

BACKGROUND

Small-cell lung cancer (SCLC) is an aggressive malignancy with a poor prognosis. Limited-stage (LS)-SCLC comprises only one-third of SCLC cases, resulting in limited molecularly targeted therapies and treatment options. Despite advances in thoracic and cranial irradiation leading to improved outcomes, a notable proportion of patients develop brain metastasis (BM), highlighting the importance of identifying high-risk patients for tailored screening and treatment strategies.

MATERIALS AND METHODS

We analyzed baseline tumor biopsies from 180 LS-SCLC patients who received frontline definitive chemoradiotherapy (dCRT) using a 474-gene pan-cancer panel. The cumulative incidence of BM was calculated with death scored as a competing risk. Independent prognostic factors for BM risk were identified using the Fine-Gray model.

RESULTS

Alterations in the cell cycle pathway, particularly RB1 mutations, were more common in patients with BM, while FLT4 mutations were more frequent in those without BM (P=0.002 and P=0.021, respectively). Significant risk factors for BM include smoking (subdistribution hazard ratio [SHR]: 1.73; 95 % confidence interval [CI]: 1.11-2.70; P=0.016), RB1 mutations (SHR: 2.19; 95 % CI: 1.27-3.81; P=0.005), and BCL3 amplification (SHR: 2.27; 95 % CI: 1.09-4.71; P=0.028). Conversely, prophylactic cranial irradiation (PCI) (SHR: 0.39; 95 % CI: 0.25-1.60; P<0.001), FLT4 mutations (SHR: 0.26; 95 % CI: 0.07-0.98; P=0.047), and NOTCH pathway alterations (SHR: 0.65; 95 % CI: 0.43-1.00; P=0.049) were associated with a lower incidence of BM in LS-SCLC. Notably, consolidation PCI therapy did not reduce the BM risk in patients with baseline RB1 mutations, with BM occurrence probabilities of 34.7 % at 20 months and 62.6 % at 40 months.

CONCLUSION

Our study yields valuable insights into the genetic characteristics of LS-SCLC patients with and without BM, aiding the development of personalized treatment strategies. Identifying risk factors associated with the incidence and timing of BM, within the standard regimen of dCRT followed by PCI, may help optimize clinical decision-making for LS-SCLC.

The role of stathmin expression in the differential diagnosis, prognosis, and potential treatment of ovarian sex cord-stromal tumors

BACKGROUND

Stathmin, a cytosolic microtubule-destabilizing phosphoprotein involved in the regulation of mitosis, is widely expressed in various malignancies and acts as an adverse prognostic factor. Our research analyzed its immunohistochemical expression on a large cohort of ovarian sex cord-stromal tumors, evaluating its potential utility in differential diagnosis, prognosis, and therapeutic application.

METHODS

We examined 390 cases of ovarian sex cord-stromal tumors including 281 adult granulosa cell tumors (AGCT), 5 juvenile granulosa cell tumors (JGCT), 33 Sertoli-Leydig cell tumors (SLCT), 50 fibromas/thecomas (F/T), 11 Leydig cell tumors/steroid cell tumors (LCT/SterCT), 5 sex-cord stromal tumors NOS (SCST-NOS), 3 Sertoli cell tumors (SCT), and 2 sclerosing stromal tumors (ScST). Immunohistochemical analysis was performed using TMAs.

RESULTS

Strong expression (> 50%) was observed in all cases of AGCT, JGCT, SLCT, SCST-NOS, SCT and 1 ScST. The other case of ScST exhibited mild expression (5-10%). The negative cases included exclusively F/T and LCT/SterCT, with F/T showing 24% of negative cases and LCT/SterCT comprising 64% of negative cases.

CONCLUSION

The results of our study indicate that stathmin is neither a prognostic marker nor suitable for the differential diagnosis of challenging cases of ovarian sex cord-stromal tumors. However, its predictive value may be theoretically significant, as a decrease in stathmin expression potentialy influences response to chemotherapy treatment.

Tau and stathmin proteins in breast cancer: A potential therapeutic target

Breast cancer is the most common malignant neoplasm among women, responsible for 30% of all malignant tumours, and the second most significant reason of cancer fatality in women. Treatment failure and tumour recurrence are common outcomes of chemotherapy when patients develop multidrug resistance (MDR). New therapeutic methods like molecularly targeted therapeutic interventions need a thorough understanding of malignant tumour's molecular processes. Numerous studies published in the last few years indicate that stathmin and tubulin-associated units (tau) are upregulated in a range of human malignant tumours, suggesting that they may enhance the incidence and progression of malignancies. By promoting cancer cell reproduction, infiltration and generating drug resistance, these proteins aid in the disease's development. Existing information on the expression of tau protein and stathmin in breast cancer, as well as their involvement in treatment methods, is summarized in this literature review.

MicroRNA-193b regulates human ovarian cancer cell growth via targeting STMN1

Ovarian cancer is the eighth most common malignancy among women worldwide. Ovarian cancer exhibits no obvious symptoms in the early stage of tumorigenesis and currently, no effective methods for the early detection and treatment of ovarian cancer have been established. Therefore, the identification of novel targets is critical to the early diagnosis and clinical treatment of ovarian cancer. microRNAs (miRs) are small non-coding RNAs, which serve an important biological role in a number of physiological processes and in oncogenesis. Previous studies have reported that miRNA-193b is dysregulated in a variety of types of human cancer. However, the roles of miRNA-193b in human ovarian cancer has not been determined. The present study investigated the roles of miRNA-193b in human ovarian cancer cells. Reverse transcription-quantitative PCR results indicated that the expression of miRNA-193b in ovarian cancer cells was significantly down-regulated compared with non-malignant cells. Cell counting kit-8 results indicated that the up-regulation of miRNA-193b inhibited ovarian cancer cell proliferation and induced ovarian cancer cell apoptosis. The present study also indicated that stathmin 1 (STMN1) was a direct target of miRNA-193b, and the up-regulation of miRNA-193b significantly decreased the expression of STMN1 in ovarian cancer cells. In conclusion, the results demonstrated that miRNA-193b serves as a tumor suppressor in human ovarian cancer by inhibiting cell proliferation and inducing cell apoptosis. Therefore, the assessment of miRNA-193b may provide insight into a novel diagnostic biomarker and potential therapeutic target for patients with ovarian cancer.

Sonic Hedgehog/Gli1 Signaling Pathway Regulates Cell Migration and Invasion via Induction of Epithelial-to-mesenchymal Transition in Gastric Cancer

Background: The aberrant activation of the Sonic hedgehog (Shh) signaling pathway is involved in progression of several types of cancer, including gastric cancer (GC). However, it remains uncertain whether it also plays a critical role in promoting cancer initiation and progression by inducing epithelial-to-mesenchymal transition (EMT) in GC. Thus, the aim of the present study was to determine whether the Shh pathway is involved in GC, and to investigate the function of the Shh pathway in the induction of EMT in GC. Materials and methods: The expression levels of Shh pathway members and EMT markers were examined in GC tissues by immunohistochemistry. The association between these factors and patient clinicopathological characteristics was analyzed. In addition, Gli-antagonist 61 (GANT61) was used to block Shh/Gli1 pathway activity, and recombinant Shh proteins (N-Shh) were used to activate the Shh pathway in GC cells. Wound healing and Transwell invasion and migration assays were performed to assess the effects of the Shh pathway on the migration and invasion of GC cells in vitro. Furthermore, western blot analysis was used to examine the changes in protein expression. Results: The results demonstrated that these Shh/Gli1 pathway members were upregulated in GC tissues, and that Gli1 upregulation was associated with tumor progression and a poor prognosis. Gli1 expression was negatively associated with E-cadherin (E-Cad) expression, and positively with Vimentin (VIM) expression in GC specimens. Further analysis revealed that when the Shh/Gli1 pathway was activated, the migratory and invasive abilities of GC cells were enhanced, and the expression levels of Gli1 and VIM were increased, while E-Cad expression was decreased. Opposite results were observed when the Shh/Gli1 pathway was blocked by GANT61. Conclusions: The present study indicated that the Shh/Gli1 pathway exhibits an abnormal activation pattern in GC with possible predictive and prognostic significance. The Shh/Gli1 pathway may promote the migratory and invasive potential of GC cells by inducing EMT. The Shh/Gli1 pathway can thus be considered as a potential therapeutic target for GC.

lncRNA UCA1 Increases Proliferation and Multidrug Resistance of Retinoblastoma Cells Through Downregulating miR-513a-5p

Chemoresistance is one of the major obstacles for cancer therapy. Abnormal expression of long noncoding RNAs (lncRNAs) was broadly implicated in chemoresistance of multiple cancers. This study was aimed to investigate the function of urothelial cancer associated 1 (UCA1) in multidrug resistance of retinoblastoma and its potential molecular mechanism. In this study, we observed that UCA1 was significantly upregulated in chemoresistant retinoblastoma tissues and multidrug resistant retinoblastoma cell lines and predicted an unfavorable overall survival. Functionally, knockdown of UCA1 remarkably inhibited proliferation and sensitized retinoblastoma cells to multiple chemotherapy drugs, including vincristine (VCR), carboplatin (CBP), cisplatin (DDP), VP-16 (etoposide), and 5-fluorouracil (5-Fu). Mechanistic studies demonstrated that UCA1 functioned as a miRNA sponge to increase stathmin 1 (STMN1) expression through sponging miR-513a-5p. In addition, silence of miR-513a-5p or STMN1 overexpression could partly reverse UCA1 knockdown-induced inhibitory effects on proliferation and multidrug resistance of retinoblastoma cells. Overall, this study is the first to demonstrate that UCA1 plays a critical role in retinoblastoma chemoresistance, and UCA1 may serve as a potential diagnostic biomarker and therapeutic target of retinoblastoma.

Association of STMN1 with survival in solid tumors: A systematic review and meta-analysis

BACKGROUND

The prognostic value of Stathmin 1 (STMN1) in malignant solid tumors remains controversial. Thus, we conducted this meta-analysis to summarize the potential value of STMN1 as a biomarker for predicting overall survival in patients with solid tumor.

METHODS

We systematically searched eligible studies in PubMed, Web of Science, and EMBASE from the establishment date of these databases to September 2018. Hazard ratio (HR) and its 95% confidence interval (CI) was used to assess the association between STMN1 expression and overall survival.

RESULTS

A total of 25 studies with 4625 patients were included in this meta-analysis. Our combined results showed that high STMN1 expression was associated with poor overall survival in solid tumors (HR = 1.85, 95% CI 1.55, 2.21). In general, our subgroup and sensitivity analyses demonstrated that our combined results were stable and reliable. However, from the results of the subgroups we found that high STMN1 expression was not related to overall survival in colorectal cancer and endometrial cancer anymore, suggesting that much caution should be taken to interpret our combined result, and more studies with large sample sizes are required to further explore the prognostic value of STMN1 expression in the specific type of tumors, especially colorectal cancer and endometrial cancer.

CONCLUSIONS

STMN1 could serve as a prognostic biomarker and could be developed as a valuable therapeutic target for patients with solid tumors. However, due to the limitations of the present meta-analysis, this conclusion should be taken with caution. Further studies adequately designed are required to confirm our findings.

Stathmin gene silencing suppresses proliferation, migration and invasion of gastric cancer cells via AKT/sCLU and STAT3 signaling

Globally, gastric cancer is the fifth most common malignancy, with high rates of incidence and mortality. The high mortality rate and poor prognosis of gastric cancer are closely associated with its profound invasiveness, high incidence of metastasis, rapid proliferation, and high rate of recurrence. Previous studies have confirmed that stathmin (STMN) has an important role in the occurrence, development and prognosis of gastric cancer. However, the detailed mechanisms by which STMN affects these processes remain unclear. The aim of the present study was to determine how STMN promotes invasion, migration and proliferation in gastric cancer tumor cells. The results of immunohistochemistry indicated that STMN is overexpressed in stomach neoplasm tissues, and that it is associated with migration, invasion, proliferation and anti‑apoptotic states of gastric cancer cells. The secretory proteins of gastric cancer cells with or without STMN knockdown were further analyzed using the isobaric tags for relative and absolute quantitation method to identify differentially expressed proteins verified by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. Inhibition of STMN decreases the levels of clusterin, cystatin C and matrix metalloproteinases, followed by inhibiting the protein kinase B and signal transducer and activation of transcription activation. These findings suggest that STMN could be a promising therapeutic target for gastric cancer.

Clinical significance of Stathmin1 expression and epithelial-mesenchymal transition in curatively resected gastric cancer

In our previous study, it was demonstrated that the Stathmin1 (STMN1) is overexpressed in gastric cancer (GC) and that its high expression level is associated with tumor invasion and metastasis. Epithelial-mesenchymal transition (EMT) has also been shown to be critically involved in GC invasion and metastasis. Certain studies have indicated that STMN1 may serve an important role in the EMT process. However, the association between STMN1 expression and EMT-associated markers, as well as clinicopathological characteristics of patients with GC, remains unclear. The aim of the present study was to investigate the clinicopathological significance and prognostic value of STMN1 and EMT-associated markers in GC. The expression of STMN1 and the EMT-associated proteins E-cadherin (E-Cad) and vimentin (VIM) were analyzed by immunohistochemistry in GC and adjacent non-tumorous tissues. Associations between the expression of these markers and clinicopathological parameters were analyzed. The association between STMN1 expression and EMT-associated markers was investigated in the GC cell lines BGC-803 and SGC-7901. The results revealed that STMN1 was expressed in 63.5% of the 167 GC tissues, which was significantly higher than the percentage observed in the adjacent non-tumorous tissues (P=0.003). The STMN1 expression was demonstrated to be positively associated with the VIM levels (P=0.001) and negatively associated with the E-Cad levels (P=0.022) in GC tissues. The STMN1 expression was associated with Lauren's Classification, invasion depth, lymph node metastasis and pathological Tumor-Node-Metastasis (pTNM) stage (P<0.05). In the univariate analyses, the high E-Cad expression was a positive prognostic indicator for overall survival, whereas the high STMN1 and VIM expression was a negative indicator. COX multiple regression analysis demonstrated that the pTNM stage [hazard ratio (HR) 1.912, 95% confidence interval (CI): 1.282–2.851, P=0.001] and E-Cad expression (HR 0.403, 95% CI: 0.249–0.650, P=0.000) were independent prognostic factors. It was also revealed that the expression level of E-Cad decreased, while the expression level of VIM increased by depleting STMN1 levels in GC cells. The present results suggest that the aberrant expression of STMN1 may promote tumor progression through EMT in GC.

Stathmin is a potential therapeutic target but not a prognostic marker in melanoma: an immunohistochemical study of 323 melanocytic lesions

In several solid tumors, an increased stathmin expression is associated with both poor prognosis and resistance to certain chemotherapy types. However, the data regarding melanocytic lesions are very limited. The goals of our study are as follows: the assessment of stathmin expression in benign and malignant melanocytic lesions, and the significance of its expression for the differential diagnostics between benign and malignant lesions; the analysis of the prognostic significance of stathmin expression in melanoma; and the evaluation of stathmin expression in melanoma and melanoma metastases with respect to possible therapeutic targeting. Immunohistochemical analysis of stathmin expression was done in 323 melanocytic lesions, including 205 primary cutaneous melanomas, 60 melanoma metastases, and 58 melanocytic nevi. Stathmin expression was found in all analyzed groups of melanocytic lesions. Using the H-scoring system, the observed intensity of expression was as follows: melanocytic nevi: 146.1 (mean) and 150 (median); melanomas: 116.7 (mean) and 110 (median); and melanoma metastases: 136.8 (mean) and 140 (median). The stathmin expression was significantly lower in the cohort of primary melanomas when compared with metastases and nevi (P=0.001). The stathmin expression showed no prognostic significance. The high stathmin expression in melanoma suggests that stathmin might be a promising marker for therapeutic targeting in ongoing clinical trials. Compared with several other solid tumors, stathmin expression in melanoma showed no prognostic significance. The potential use of stathmin expression in differential diagnostics is limited by its common expression, and despite the statistically significant differences between nevi and melanoma, it may not be used in this setting.

High STMN1 level is associated with chemo-resistance and poor prognosis in gastric cancer patients

Background:

Stathmin1 (STMN1) is a cytosolic phosphoprotein that regulates cellular microtubule dynamics and is known to have oncogenic activity. Despite several reports, its roles in gastric cancer (GC) remain unclear owing to a lack of analyses of highly metastatic cases. This study aimed to investigate STMN1 as a prognostic and predictive indicator of response to paclitaxel therapy in patients with GC, including inoperable cases.

Methods:

Immunohistochemical analysis of STMN1 was performed on both operable (n=95) and inoperable GC (n=61) samples. The roles of STMN1 in cancer cell proliferation and sensitivity to a microtubule-targeting drug, paclitaxel, were confirmed by knockdown experiments using GC cell lines.

Results:

Multivariate and Kaplan–Meier analyses demonstrated that high STMN1 was predictive of poor prognosis in both the groups. In the operable cohort, STMN1 expression correlated with cancer curability, recurrence, and resistance to adjuvant therapy. A correlation with paclitaxel resistance was observed in inoperable cases. Knockdown of STMN1 in GC cell lines inhibited proliferation and sensitised the cells to paclitaxel by enhancing apoptosis.

Conclusions:

STMN1 is a possible biomarker for paclitaxel sensitivity and poor prognosis in GC and could be a novel therapeutic target in metastatic GC.

Clinical significance of UGT1A1 polymorphism and expression of ERCC1, BRCA1, TYMS, RRM1, TUBB3, STMN1 and TOP2A in gastric cancer

BACKGROUND

Individualized therapeutic regimen is a recently intensively pursued approach for targeting diseases, in which the search for biomarkers was considered the first and most important. Thus, the goal of this study was to investigate whether the UGT1A1, ERCC1, BRCA1, TYMS, RRM1, TUBB3, STMN1 and TOP2A genes are underlying biomarkers for gastric cancer, which, to our knowledge, has not been performed.

METHODS

Ninety-eight tissue specimens were collected from gastric cancer patients between May 2012 and March 2015. A multiplex branched DNA liquidchip technology was used for measuring the mRNA expressions of ERCC1, BRCA1, TYMS, RRM1, TUBB3, STMN1 and TOP2A. Direct sequencing was performed for determination of UGT1A1 polymorphisms. Furthermore, correlations between gene expressions, polymorphisms and clinicopathological characteristics were investigated.

RESULTS

The expressions of TYMS, TUBB3 and STMN1 were significantly associated with the clinicopathological characteristics of age, gender and family history of gastric cancer, but not with differentiation, growth patterns, metastasis and TNM staging in patients with gastric cancer. No clinical characteristics were correlated with the expressions of ERCC1, BRCA1, RRM1 and TOP2A. Additionally, patients carrying G allele at -211 of UGT1A1 were predisposed to developing tubular adenocarcinoma, while individuals carrying 6TAA or G allele respectively at *28 or -3156 of UGT1A1 tended to have a local invasion.

CONCLUSIONS

The UGT1A1 polymorphism may be useful to screen the risk population of gastric cancer, while TYMS, TUBB3 and STMN1 may be potential biomarkers for prognosis and chemotherapy guidance.

Overexpression of stathmin promotes metastasis and growth of malignant solid tumors: a systemic review and meta-analysis

Stathmin has been investigated to be involved in development and progress of malignant tumors. This study was to clarify the relationship between expression of stathmin and tumors and assess its clinical significance. We identified 25 studies with a total of 3,571 individuals from the electronic bibliographic databases and strictly evaluated the quality and heterogeneity of included studies. We analysed the relationship between expression of stathmin and clinical characteristics by the fixed-effects and random-effects of meta-analysis and constructed a summary receiver-operator characteristic curve to estimate the test characteristics. The results showed that patients with cancer displayed a higher stathmin expression than those of non-cancer individuals (OR, 0.31), and overexpression of stathmin correlated with tumor cell differentiation (OR, 0.73), lymph node invasion (OR, 0.80) and high TNM stage (OR, 0.67). The pooled sensitivity of stathmin for distinguishing malignant tumors was 0.73 and the specificity was 0.77. The maximum balance joint for sensitivity and specificity (the Q-value) was 0.7566 and the area under the curve (AUC) was 0.8234. In conclusion, these results showed that overexpression of stathmin intimately correlated with malignant behavior of tumors, suggesting it could be a risk factor of malignant tumors. Stathmin had great sensitivity and specificity indicated it should be a significant molecular biomarker for malignant tumors.

Stathmin-dependent molecular targeting therapy for malignant tumor: the latest 5 years' discoveries and developments

Knowledge of the molecular mechanisms on malignant tumors is very critical for the development of new treatment strategies like molecularly targeted therapies. In last 5 years, many investigations suggest that stathmin is over-expressed in a variety of human malignant tumors, and potentially promotes the occurrence and development of tumors. Rather, down-regulation of stathmin can reduce cell proliferation, motility and metastasis and induce apoptosis of malignant tumors. Thus, a stathmin antagonist, such as a specific inhibitor (antibody, small molecule compound, peptide, or siRNA), may be a novel strategy of molecular targeted therapy. This review summarizes the research progress of recent 5 years on the role of stathmin in tumorigenesis, the molecular mechanisms and development of anti-stathmin treatment, which suggest that continued investigations into the function of stathmin in the tumorigenesis could lead to more rationally designed therapeutics targeting stathmin for treating human malignant tumors.

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.

Regulation of Oncoprotein 18/Stathmin Signaling by ERK Concerns the Resistance to Taxol in Nonsmall Cell Lung Cancer Cells

Taxol is a cytotoxic antiepithelioma chemotherapy drug widely used clinically, which results in appearing a broad range of taxol-resistant tumors. Oncoprotein 18 (Op18)/stathmin is a genetically highly conserved small-molecule cytosolic phosphoprotein and highly expressed in tumors. Extracellular signal-regulated kinase (ERK) is a main member of mitogen-activated protein kinases (MAPKs). The study demonstrated that combination of blockage of ERK signal by ERK inhibitor PD98059 and Taxol greatly promoted taxol-induced cellular apoptosis and growth inhibition, decreased the expression of Op18/stathmin and total levels of phosphor-Op18/stathmin, while weakened the cyclin-dependent kinase 2 (cdc2) activity and antiapoptotic protein Bcl-2 expression and inhibited IL-10 autocrine in taxol-resistant NCI-H1299 cells; Taxol-resistant NCI-H1299 cells expressed high levels of ERK and phosphor-ERK in contrast to taxol-sensitive CNE1 cells, and ERK mainly phosphorylated Op18/stathmin at Ser 25 site. These findings suggest that ERK-mediated Op18/stathmin is involved in taxol resistance of tumors; blockage of ERK signal improves the sensitivity of tumor cells to taxol, which provides new clues for treating taxol-resistant carcinomas.

Overexpression of SCLIP promotes growth and motility in glioblastoma cells

SCLIP, a microtubule-destabilizing phosphoprotein, is known to be involved in the development of the central nervous system (CNS). It has been well established that there are notable parallels between normal development and tumorigenesis, especially in glioma. However, no studies have examined the significance of SCLIP in gliomagenesis. To address this, we investigated the expression of SCLIP and its roles in the development of gliomas. Notably, we found that SCLIP was highly expressed in various grades of glioma samples, as compared with normal brain tissues. Overexpression of SCLIP dramatically stimulated tumor cell migration and invasion as well as proliferation and downregulation of SCLIP showed opposite effects, establishing an important oncogenic role for this gene. Furthermore, we revealed that STAT3 was required to maintain SCLIP stability, suggesting that overexpression of STAT3 may be a critical step to facilitate microtubule dynamics and subsequently promotes migration and invasion of glioma cells. Taken together, our findings demonstrate that SCLIP plays an important role in glioma pathology, and may represent a novel therapeutic strategy against human glioma.

Comparative Tissue Proteomics of Microdissected Specimens Reveals Novel Candidate Biomarkers of Bladder Cancer

More than 380,000 new cases of bladder cancer are diagnosed worldwide, accounting for ∼150,200 deaths each year. To discover potential biomarkers of bladder cancer, we employed a strategy combining laser microdissection, isobaric tags for relative and absolute quantitation labeling, and liquid chromatography-tandem MS (LC-MS/MS) analysis to profile proteomic changes in fresh-frozen bladder tumor specimens. Cellular proteins from four pairs of surgically resected primary bladder cancer tumor and adjacent nontumorous tissue were extracted for use in two batches of isobaric tags for relative and absolute quantitation experiments, which identified a total of 3220 proteins. A DAVID (database for annotation, visualization and integrated discovery) analysis of dysregulated proteins revealed that the three top-ranking biological processes were extracellular matrix organization, extracellular structure organization, and oxidation-reduction. Biological processes including response to organic substances, response to metal ions, and response to inorganic substances were highlighted by up-expressed proteins in bladder cancer. Seven differentially expressed proteins were selected as potential bladder cancer biomarkers for further verification. Immunohistochemical analyses showed significantly elevated levels of three proteins-SLC3A2, STMN1, and TAGLN2-in tumor cells compared with noncancerous bladder epithelial cells, and suggested that TAGLN2 could be a useful tumor tissue marker for diagnosis (AUC = 0.999) and evaluating lymph node metastasis in bladder cancer patients. ELISA results revealed significantly increased urinary levels of both STMN1 and TAGLN2 in bladder cancer subgroups compared with control groups. In comparisons with age-matched hernia urine specimens, urinary TAGLN2 in bladder cancer samples showed the largest fold change (7.13-fold), with an area-under-the-curve value of 0.70 (p < 0.001, n = 205). Overall, TAGLN2 showed the most significant overexpression in individual bladder cancer tissues and urine specimens, and thus represents a potential biomarker for noninvasive screening for bladder cancer. Our findings highlight the value of bladder tissue proteome in providing valuable information for future validation studies of potential biomarkers in urothelial carcinoma.

Roles of human papillomavirus infection and stathmin in the pathogenesis of sinonasal inverted papilloma

BACKGROUND

The purpose of this study was to investigate roles of human papillomavirus (HPV) infection and stathmin in sinonasal inverted papilloma (SNIP).

METHODS

HPV DNA detection was performed by the fluorescence-based polymerase chain reaction (PCR) method. Stathmin protein expression was investigated by the immunohistochemistry method and mRNA expression of stathmin, Kif2a, and cyclin D1 were assessed by real-time PCR in SNIP and control subjects.

RESULTS

The positive rate of HPV DNA detected in SNIP was about 53.6% (15 of 28). Recurrent cases showed a higher rate of HPV infection compared with initial cases and higher Krouse stage (T3 + T4) cases showed higher rate of HPV infection than lower Krouse stage (T1 + T2) cases. Stronger expression of stathmin, Kif2a, and cyclin D1 were observed in SNIP, especially HPV(+) SNIP.

CONCLUSION

HPV infection was closely associated with recurrence and progression of SNIP. Stathmin is a valuable prognostic marker and could be considered as a therapeutic target in patients with SNIP.

Phase 1 Trial of Bi-shRNA STMN1 BIV in Refractory Cancer

Stathmin1 (STMN1) is a microtubule modulator that is expressed in multiple cancers and correlates with poor survival. We previously demonstrated in vivo safety of bifunctional (bi) shRNA STMN1 bilamellar invaginated vesicle (BIV) and that systemic delivery correlated with antitumor activity. Patients with superficial advanced refractory cancer with no other standard options were entered into trial. Study design involved dose escalation (four patients/cohort) using a modified Fibonacci schema starting at 0.7 mg DNA administered via single intratumoral injection. Biopsy at baseline, 24/48 hours and resection 8 days after injection provided tissue for determination of cleavage product using next-generation sequencing (NGS) and reverse transcription quantitative polymerase chain reaction (RT-qPCR), 5' RLM rapid amplification of cDNA ends (RACE) assay. Serum pharmacokinetics of circulating plasmid was done. Twelve patients were entered into three dose levels (0.7, 1.4, 7.0 mg DNA). No ≥ grade 3 toxic effects to drug were observed. Maximum circulating plasmid was detected at 30 seconds with less than 10% detectable in all subjects at 24 hours. No toxic effects were observed. Predicted cleavage product was detected by both NGS (n = 7/7 patients analyzed, cohorts 1, 2) and RLM RACE (n = 1/1 patients analyzed cohort 3). In conclusion, bi-shRNA STMN1 BIV is well tolerated and detection of mRNA target sequence-specific cleavage product confirmed bi-shRNA BIV mechanism of action.

Overexpression of stathmin 1 is a poor prognostic biomarker in non-small cell lung cancer

Stathmin 1 (STMN1), a major microtubule-depolymerizing protein, is involved in cell cycle progression and cell motility. However, the clinical significance of STMN1 expression in non-small cell lung cancer (NSCLC) has not been determined. The expression pattern of STMN1 mRNA was analyzed by quantitative real-time PCR (qRT-PCR) in 37 cases of NSCLC and in the corresponding non-tumor tissue samples. Furthermore, immunohistochemistry was performed to detect STMN1 protein expression in 113 primary NSCLC tissues. The functional role of STMN1 in lung cancer cell lines was evaluated by small interfering RNA-mediated depletion followed by analyses of cell proliferation and invasion. We found that the STMN1 mRNA and protein levels in NSCLC tissues were significantly higher than those in the corresponding non-tumor tissues (P<0.001). In addition, increased STMN1 expression was correlated with poor tumor differentiation (P<0.001), large tumor size (P=0.022), advanced N stage (P=0.033), and advanced TNM stage (P<0.001). Kaplan-Meier analysis indicates that NSCLC patients with higher STMN1 expression showed significantly worse survival. Moreover, multivariate analysis indicates that higher STMN1 protein expression was an independent prognostic factor of disease-specific survival (HR 2.247, 95%CI 1.320-3.825, P=0.003). Finally, the knockdown of STMN1 in lung cancer cells resulted in a decrease in cellular proliferation and invasion. Our findings suggest that STMN1 may have an important role in NSCLC progression and could serve as a potential prognostic marker for patients with NSCLC.

Unbiased proteomic and transcript analyses reveal that stathmin-1 silencing inhibits colorectal cancer metastasis and sensitizes to 5-fluorouracil treatment

Colorectal cancer metastasis is a major cause of mortality worldwide, which may only be controlled with novel methods limiting tumor dissemination and chemoresistance. High stathmin-1 (STMN1) expression was previously established as a hallmark of colorectal cancer progression and predictor of poor survival; however, the mechanism of action is less clear. This work demonstrates that STMN1 silencing arrests tumor-disseminative cascades by inhibiting multiple metastatic drivers, and repressing oncogenic and mesenchymal transcription. Using a sensitive iTRAQ labeling proteomic approach that quantified differential abundance of 4562 proteins, targeting STMN1 expression was shown to reinstate the default cellular program of metastatic inhibition, and promote cellular adhesion via amplification of hemidesmosomal junctions and intermediate filament tethering. Silencing STMN1 also significantly improved chemoresponse to the classical colorectal cancer therapeutic agent, 5FU, via a novel caspase-6 (CASP6)-dependent mechanism. Interestingly, the prometastatic function of STMN1 was independent of p53 but required phosphorylations at S25 or S38; abrogating phosphorylative events may constitute an alternative route to achieving metastatic inhibition. These findings establish STMN1 as a potential target in antimetastatic therapy, and demonstrate the power of an approach coupling proteomics and transcript analyses in the global assessment of treatment benefits and potential side-effects.

IMPLICATIONS

Stathmin-1 is a potential candidate in colorectal cancer therapy that targets simultaneously the twin problems of metastatic spread and chemoresistance.

miR-193b directly targets STMN1 and uPA genes and suppresses tumor growth and metastasis in pancreatic cancer

Pancreatic cancer has the poorest prognosis among all cancer types, due to its late diagnosis and the lack of effective therapies. Therefore, identification of novel gene targets, which are differentially expressed in pancreatic cancer and functionally involved in the malignant phenotype, is critical to achieve early diagnosis and develop effective therapeutic strategies. microRNAs (miRNAs) are small non-coding RNAs, which negatively regulate the expression of their targets. Due to their various targets, miRNAs play a key role in a number of physiological processes and in oncogenesis. Therefore, investigating the role of miRNAs in tumor may contribute to the development of new diagnostic and therapeutic tools for various types of cancer, including pancreatic cancer. Here, we investigated the role of miR-193b in pancreatic cancer. Our data showed that the expression of miR-193b is markedly decreased in pancreatic cancer tissues compared to adjacent healthy tissues. The Panc-1 cell line transfected with the miR‑193b exhibited significantly decreased proliferative, migratory, and invasive ability compared to untransfected cells. Moreover, miR-193b inhibited the expression of stathmin 1 (STMN1) and urokinase-type plasminogen activator (uPA) in Panc-1 cells. These data suggest that miR-193b acts as a tumor suppressor in pancreatic cancer. Therefore, miR-193b may constitute a promising therapeutic agent for the suppression of pancreatic cancer cell growth and metastasis.

miR-223 inhibits dengue virus replication by negatively regulating the microtubule-destabilizing protein STMN1 in EAhy926 cells

The pathogenesis of dengue virus (DENV) infection is not completely understood. Endothelial cells may act as a target of the virus and be involved in disease pathogenesis. Therefore, the identification of host cell components involved in DENV replication would provide useful information for better understanding DENV infection. In this study, a significantly decreased level of miR-223 was found in DENV2-infected EAhy926 cells, a human endothelial-like cell line, whereas miR-223 overexpression inhibited DENV2 replication. Furthermore, we identified that miR-223 directly targeted the 3' untranslated region (3'UTR) of the messenger RNA (mRNA) for microtubule-destabilizing protein stathmin 1 (STMN1), thereby reducing its mRNA and protein levels. The depletion of miR-223 or overexpression of STMN1 enhanced DENV2 replication, whereas the opposite (increased miR-223 or decreased STMN1) suppressed DENV2 replication, indicating that miR-223 down-regulates STMN1 expression by targeting the 3'UTR of the STMN1 gene to inhibit DENV2 replication. Finally, we demonstrated that two transcription factors, C/EBPα and E2F1, are involved in the regulation of miR-223 levels after DENV2 infection in EAhy926 cells. Collectively, our results suggest that miR-223 may act as a novel antiviral factor, which may open an avenue to limit DENV infection.

Elevated plasma D-dimer levels correlate with long term survival of gastric cancer patients

BACKGROUND

Increasing evidence indicated plasma D-dimer could be regarded as a marker in cancers, however, its role in gastric cancer is still largely unknown.

METHODS

Plasma D-dimer levels were measured by enzyme linked fluorescent immunoassays and evaluated by receiver operating characteristic (ROC) curves for peritoneal dissemination in gastric cancer and healthy subjects. The overall survival (OS) characteristics were determined using Kaplan-Meier and Cox regression analyses.

RESULTS

The average of the plasma D-dimer levels for gastric cancer patients was significantly higher than the healthy subjects. A Spearman correlation analysis showed that plasma D-dimer levels correlated with the depth of invasion, lymph node metastasis, peritoneal dissemination, distant metastasis, tumor size and TNM stage. The mean plasma D-dimer level was 2.20 ± 1.51 µg/mL in peritoneal dissemination patients and 1.01 ± 0.79 µg/mL in non-peritoneal dissemination patients (P<0.001). Additionally, the mean plasma D-dimer concentration in patients alive at the final follow-up evaluation was 0.79 ± 0.72 µg/mL,which was significantly lower than the amounts determined for the deceased patients (1.36 ± 1.13 µg/mL) (P<0.001). The AUC of D-dimer was 0.833 (95%CI: 0.780-0.885). At a cut-off value of 1.465 µg/mL, the D-dimer measurement had a sensitivity of 78.00%, a specificity of 83.76% and an accuracy of 82.59%. The median OS was 48.10 months (95% CI: 43.88-52.31) in patients with plasma D-dimer levels less than 1.465 µg/mL and 22.39 months (95% CI: 16.95-27.82) in patients with plasma D-dimer levels exceeding 1.465 µg/mL (log-rank test, P<0.001). Importantly, plasma D-dimer levels exceeding 1.465 µg/mL were significantly associated with poor OS, as determined using a multivariate Cox regression analysis (hazard ratio [HR], 2.28; 95%CI: 1.36-3.81; P = 0.002).

CONCLUSIONS

Plasma D-dimer levels are increased in gastric cancer patients and may be a valuable biomarker for peritoneal dissemination, with high D-dimer levels predicting poor outcomes for gastric cancer patients.