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

Paris saponin VII inhibits triple-negative breast cancer by targeting the MEK/ERK/STMN1 signaling axis

BACKGROUND

Triple-negative breast cancer (TNBC) is a category of breast cancer characterized with high molecular heterogeneity. Owing to the lack of effective therapeutic strategies, patients with TNBC have a poor prognosis. Paris saponin VII (PSⅦ), a steroidal saponin extracted from the rhizome of Trichillium tschonoskii Maxim, exhibits excellent anti-cancer activity in a variety of solid tumors. However, the role and potential mechanism of PSⅦ against TNBC remain unexplored.

PURPOSE

This study aimed to elucidate the therapeutic effects of PSⅦ against TNBC and explore the potential mechanism of action.

METHODS

We combined the analysis of public single-cell sequencing data with weighted gene co-expression network analysis (WGCNA) to identity differentially expressed genes (DEGs) that distinguished malignant and normal epithelial cells in TNBC. Subsequently, the biological features of DEGs in TNBC were evaluated. Gene set enrichment analysis (GSEA) was used to define potential pathways associated with the DEGs. The pharmacological activity of PSⅦ for TNBC was evidenced via in vitro and in vivo experiments, and molecular docking, molecular dynamics (MD), surface plasmon resonance (SPR) assay and western blotting were employed to confirm the relative mechanisms.

RESULTS

Single-cell sequencing and WGCNA revealed STMN1 as a pivotal biomarker of TNBC. STMN1 overexpression in TNBC was associated with poor patient prognosis. GSEA revealed a significant accumulation of STMN1 within the MAPK signaling pathway. Furthermore, In vitro experiments showed that PSⅦ showed significantly suppressive actions on the proliferation, migration and invasion abilities for TNBC cells, while inducing apoptosis. Molecular docking, MD analysis and SPR assay indicated a robust interaction between PSⅦ and the MEK protein. Western blotting revealed that PSⅦ may inhibit tumor progression by suppressing the phosphorylation of MEK1/2 and the downstream phosphorylation of ERK1/2 and STMN1. Intraperitoneal injection of PSⅦ (10 mg/kg) notably reduced tumor growth by 71.26 % in a 4T1 xenograft model.

CONCLUSION

In our study, the systems biology method was used to identify potential therapeutic targets for TNBC. In vitro and in vivo experiments demonstrated PSⅦ suppresses cancer progression by targeting the MEK/ERK/STMN1 signaling axis. For the first time, the inhibition of STMN1 phosphorylation has been indicated as a possible mechanism for the anticancer effects of PSⅦ. These results emphasize the potential value of PSⅦ as a promising anti-cancer drug candidate for further development in the field of TNBC therapeutics.

CRISPR/Cas9-Mediated CtBP1 Gene Editing Enhances Chemosensitivity and Inhibits Metastatic Potential in Esophageal Squamous Cell Carcinoma Cells

Innovative therapeutic strategies for esophageal squamous cell carcinoma (ESCC) are urgently required due to the limited effectiveness of standard chemotherapies. C-Terminal Binding Protein 1 (CtBP1) has been implicated in various cancers, including ESCC. However, the precise expression patterns and functional roles of CtBP1 in ESCC remain inadequately characterized. In this study, we aimed to investigate CtBP1 expression and its role in the resistance of ESCC to paclitaxel, an effective chemotherapeutic agent. Western blotting and immunofluorescence were applied to assess CtBP1 expression in the TE-1 and KYSE-50 cell lines. We observed the marked expression of CtBP1, which was associated with enhanced proliferation, invasion, and metastasis in these cell lines. Further, we successfully generated paclitaxel resistant ESCC cell lines and conducted cell viability assays. We employed the CRISPR/Cas9 genome editing system to disable the CtBP1 gene in ESCC cell lines. Through the analysis of the drug dose-response curve, we assessed the sensitivity of these cell lines in different treatment groups. Remarkably, CtBP1-disabled cell lines displayed not only improved sensitivity but also a remarkable inhibition of proliferation, invasion, and metastasis. This demonstrates that CtBP1 may promote ESCC cell malignancy and confer paclitaxel resistance. In summary, our study opens a promising avenue for targeted therapies, revealing the potential of CtBP1 inhibition to enhance the effectiveness of paclitaxel treatment for the personalized management of ESCC.

STNM1 in human cancers: role, function and potential therapy sensitizer

STMN1 belongs to the stathmin gene family, it encodes a cytoplasmic phosphorylated protein, stathmin1, which is commonly observed in vertebrate cells. STMN1 is a structural microtubule-associated protein (MAP) that binds to microtubule protein dimers rather than microtubules, with each STMN1 binding two microtubule protein dimers and preventing their aggregation, leading to microtubule instability. STMN1 expression is elevated in a number of malignancies, and inhibition of its expression can interfere with tumor cell division. Its expression can change the division of tumor cells, thereby arresting cell growth in the G2/M phase. Moreover, STMN1 expression affects tumor cell sensitivity to anti-microtubule drug analogs, including vincristine and paclitaxel. The research on MAPs is limited, and new insights on the mechanism of STMN1 in different cancers are emerging. The effective application of STMN1 in cancer prognosis and treatment requires further understanding of this protein. Here, we summarize the general characteristics of STMN1 and outline how STMN1 plays a role in cancer development, targeting multiple signaling networks and acting as a downstream target for multiple microRNAs, circRNAs, and lincRNAs. We also summarize recent findings on the function role of STMN1 in tumor resistance and as a therapeutic target for cancer.

ORP8 inhibits renal cell carcinoma progression by accelerating Stathmin1 degradation and microtubule polymerization

ORP8 has been reported to suppress tumor progression in various malignancies. However, the functions and underlying mechanisms of ORP8 are still unknown in renal cell carcinoma (RCC). Here, decreased expression of ORP8 was detected in RCC tissues and cell lines. Functional assays verified that ORP8 suppressed RCC cell growth, migration, invasion, and metastasis. Mechanistically, ORP8 attenuated Stathmin1 expression by accelerating ubiquitin-mediated proteasomal degradation and led to an increase in microtubule polymerization. Lastly, ORP8 knockdown partly rescued microtubule polymerization, as well as aggressive cell phenotypes induced by paclitaxel. Our findings elucidated that ORP8 suppressed the malignant progression of RCC by increasing Stathmin1 degradation and microtubule polymerization, thus suggesting that ORP8 might be a novel target for the treatment of RCC.

miR‑193b exhibits mutual interaction with MYC, and suppresses growth and metastasis of osteosarcoma

Emerging evidence has indicated that microRNAs (miRs) are involved in the malignant behavior of cancer. The present study explored the role of miR‑193b in the development and metastasis of osteosarcoma. Compared with F4 osteosarcoma cells, which have a relatively low metastatic potential, highly metastatic F5M2 cells exhibited a lower expression of miR‑193b. Furthermore, miR‑193b exerted negative effects on cell proliferation, colony formation, cell cycle progression, migration and invasion, and induced apoptosis. In vivo studies revealed negative influences of miR‑193b on tumorigenesis and metastasis. The tumor‑suppressive role of miR‑193b was achieved by targeting KRAS and stathmin 1 (STMN1). Notably, overexpression of KRAS and STMN1 attenuated the miR‑193b‑induced inhibition of malignant behaviors. There was a double‑negative regulatory loop between MYC and miR‑193b, with MYC inhibiting miR‑193b expression by directly binding to its promoter region and miR‑193b negatively influencing MYC expression indirectly through some unknown mechanism. Collectively, these findings indicated that miR‑193b may serve a tumor suppressive role in osteosarcoma by targeting KRAS and STMN1. The double‑negative regulatory loop between MYC and miR‑193b may contribute to the sustained upregulation of MYC, the downregulation of miR‑193b, and to the subsequently enhanced expression of KRAS and STMN1, which may eventually lead to the development and metastasis of osteosarcoma.

In situ antitumor vaccination: Targeting the tumor microenvironment

Tumor microenvironment is known to play important roles in tumor progression. Many therapies, targeting the tumor microenvironment, are designed and applied in the clinic. One of these approaches is in situ antitumor therapy. This way, bacteria, antibodies, plasmid DNA, viruses, and cells are intratumorally delivered into the tumor site as "in-situ antitumor vaccine," which seeks to enhance immunogenicity and generate systemic T cell responses. In addition, this intratumoral therapy can alter the tumor microenvironment from immunosuppressive to immunostimulatory while limiting the risk of systemic exposure and associated toxicity. Contemporarily, promising preclinical results and some initial success in clinical trials have been obtained after intratumoral therapy.

Possible biomarkers for predicting lymph node metastasis of esophageal squamous cell carcinoma: a review

Esophageal cancer is the eighth most common form of cancer worldwide, and esophageal squamous cell carcinoma (ESCC) is a major type of esophageal cancer that arises from epithelial cells of the esophagus. Local lymph node metastasis (LNM) is a typical sign of failure for ESCC clinical treatments, and a link has been established between LNM and the aberrant expression of specific biomarkers. In this review, we summarize what is known about nine factors significantly associated with LNM in ESCC patients: phosphatase and tensin homolog (PTEN), mucin 1, vascular endothelial growth factor-C, tumor necrosis factor alpha-induced protein 8 (TNFAIP8), Raf-1 kinase inhibitory protein, stathmin (STMN1), metastasis-associated protein 1, caveolin-1, and interferon-induced transmembrane protein 3. The function of these nine proteins involves four major mechanisms: tumor cell proliferation, tumor cell migration and invasion, epithelium–mesenchymal transition, and chemosensitivity. The roles of PTEN, STMN1, and TNFAIP8 involve at least two of these mechanisms, and we suggest that they are possible biomarkers for predicting LNM in ESCC. However, further retrospective research into PTEN, STMN1, and TNFAIP8 is needed to test their possibilities as indicators.

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 Expression is Associated with Cancer Progression and Chemo-Resistance in Lung Squamous Cell Carcinoma

BACKGROUND

Known as a microtubule-destabilizing protein, STMN1 (gene symbol: STMN1) regulates the dynamics of microtubules, cell cycle progress, and chemo-resistance against taxane agents. It is highly expressed in various human cancers and involved in cancer progression as well as poor prognosis.

METHODS

Expression of STMN1 was examined by immunohistochemistry using FFPE tissue sections from 186 patients with lung squamous cell carcinoma (LSCC). Analysis of STMN1 suppression was performed for STMN1 small interfering RNA (siRNA)-transfected LSCC cell lines to determine the change in proliferation, invasive and apoptosis abilities, and paclitaxel sensitivity.

RESULTS

The cytoplasmic STMN1 expression in LSCC was higher than in normal tissues. The high expression was significantly associated with vascular invasion (P = 0.0477) and poor prognosis. In addition, the proliferating and invasive abilities were decreased, and the apoptosis ability and paclitaxel sensitivity were increased in STMN1-suppressed LSCC cells compared with control cells.

CONCLUSION

The results suggest that STMN1 is a prognostic factor that also is associated with caner progression and chemo-resistance. Therefore, STMN1 could be a predictor for poor prognosis and a potential therapeutic target in LSCC.

A decision tree-based combination of ezrin-interacting proteins to estimate the prognostic risk of patients with esophageal squamous cell carcinoma

Our previous studies have highlighted the importance of ezrin in esophageal squamous cell carcinoma (ESCC). Here our objective was to explore the clinical significance of ezrin-interacting proteins, which would provide a theoretical basis for understanding the function of ezrin and potential therapeutic targets for ESCC. We used affinity purification and mass spectrometry to identify PDIA3, CNPY2, and STMN1 as potential ezrin-interacting proteins. Confocal microscopy and coimmunoprecipitation analysis further confirmed the colocalization and interaction of ezrin with PDIA3, CNPY2, and STMN1. Tissue microarray data of ESCC samples (n=263) showed that the 5-year overall survival (OS) and disease-free survival (DFS) were significantly lower for the CNPY2 (OS, P=.003; DFS, P=.011) and STMN1 (OS, P=.010; DFS, P=.002) high-expression groups compared with the low-expression groups. By contrast, overexpression of PDIA3 was significantly correlated with favorable survival (OS, P<.001; DFS, P=.001). Cox regression demonstrated the prognostic value of PDIA3, CNPY2, and STMN1 in ESCC. Furthermore, decision tree analysis revealed that the resulting classifier of both ezrin and its interacting proteins could be used to better predict OS and DFS of patients with ESCC. In conclusion, a signature of ezrin-interacting proteins accurately predicts ESCC patient survival or tumor recurrence.

Overexpression of stathmin plays a pivotal role in the metastasis of esophageal squamous cell carcinoma

Purpose

Esophageal squamous cell carcinoma (ESCC) is a serious malignant tumor that affects human health. We analyzed the correlation between serum stathmin level and ESCC and elucidated the molecular mechanisms of stathmin's promotion of ESCC cell invasion and metastasis.

Methods

Stathmin level in ESCC and healthy control serum were detected by enzyme-linked immunosorbent assay (ELISA), and the clinical parameters were analyzed. We established ESCC cells with stathmin overexpression or knockdown and then evaluated the effects of stathmin on invasion and metastasis in ESCC. Differentially expressed genes were analyzed by Human Transcriptome Array and confirmed by RT-PCR. The expression levels of the integrin family, focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK) were detected by immunoblotting.

Results

Serum levels of stathmin were significantly higher in ESCC than in control serum and associated with lymph node metastasis, tumor stage and size. Furthermore, we found that stathmin promoted migration and invasion of ESCC cells in vitro and in vivo. In addition, we confirmed that the activation of the integrinα5β1/FAK/ERK pathway is increased in stathmin-overexpression cells and accelerates cell motility by enhancing cell adhesion ability.

Conclusion

Stathmin may predict a potential metastasis biomarker for ESCC.

The Cdc2/Cdk1 inhibitor, purvalanol A, enhances the cytotoxic effects of taxol through Op18/stathmin in non-small cell lung cancer cells in vitro

Purvalanol A is a highly selective inhibitor of Cdc2 [also known as cyclin-dependent kinase 1 (CDK1)]. Taxol is an anti-tumor chemotherapeutic drug which is widely used clinically. In this study, the CDK1 inhibitor, purvalanol A was applied to explore the relevance of Cdc2 signaling and taxol sensitivity through analyses, such as cellular proliferation and apoptosis assays, ELISA, western blot analysis and immunoprecipitation. We demonstrated that purvalanol A effectively enhanced the taxol-induced apoptosis of NCI-H1299 cells, as well as its inhibitory effects on cellular proliferation and colony formation. In combination, purvalanol A and taxol mainly decreased the expression of oncoprotein 18 (Op18)/stathmin and phosphorylation at Ser16 and Ser38, while purvalanol A alone inhibited the phosphorylation of Op18/stathmin at all 4 serine sites. Co-treatment with purvalanol A and taxol weakened the expression of Bcl-2 and activated the extrinsic cell death pathway through the activation of caspase-3 and caspase-8. Further experiments indicated that Cdc2 kinase activities, including the expression of Cdc2 and the level of phospho-Cdc2 (Thr161) were significantly higher in taxol-resistant NCI-H1299 cells compared with the relatively sensitive CNE1 cells before and following treatment with taxol. These findings suggest that Cdc2 is positively associatd with the development of taxol resistance. The Cdc2 inhibitor, purvalanol A, enhanced the cytotoxic effects of taxol through Op18/stathmin. Our findings may prove to be useful in clinical practice, as they may provide a treatment strategy with which to to reduce the doses of taxol applied clinically, thus alleviating the side-effects.

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.

TNFAIP8 overexpression: a potential predictor of lymphatic metastatic recurrence in pN0 esophageal squamous cell carcinoma after Ivor Lewis esophagectomy

Esophageal squamous cell carcinoma (ESCC) has a poor prognosis due to high lymphatic metastatic recurrence rates after Ivor Lewis esophagectomy. We sought to investigate the correlation between tumor necrosis factor alpha-induced protein 8 (TNFAIP8) expression and postoperative lymphatic recurrence in patients with pN0 ESCC. One hundred twenty-two patients with pN0 ESCC undergoing Ivor Lewis esophagectomy were enrolled in this study. TNFAIP8 overexpression was found in 73 (59.8 %) tumor specimens. The 3-year lymphatic metastatic recurrence rate among TNFAIP8-overexpressing patients was significantly higher than in TNFAIP8-negative patients (p = 0.003). Multivariate Cox regression identified TNFAIP8 overexpression as an independent risk factor for lymphatic recurrence (p = 0.048). TNFAIP8 messenger RNA (mRNA) levels were significantly higher in patients with lymphatic recurrence than in patients without tumor recurrence (p = 0.019). Stable silencing of TNFAIP8 expression in ESCC-derived cells (Eca109) reduced proliferation, motility, and invasion and induced apoptosis. In addition, transient silencing of TNFAIP8 expression decreased cell motility and invasion and increased apoptosis in a second ESCC-derived cell line (KYSE150). Taken together, these findings suggest that TNFAIP8 overexpression is a potential biomarker to identify pN0 ESCC patients at higher risk of lymphatic recurrence who may benefit from adjuvant therapy.

MiR-193b promotes autophagy and non-apoptotic cell death in oesophageal cancer cells

BACKGROUND

Successful treatment of oesophageal cancer is hampered by recurrent drug resistant disease. We have previously demonstrated the importance of apoptosis and autophagy for the recovery of oesophageal cancer cells following drug treatment. When apoptosis (with autophagy) is induced, these cells are chemosensitive and will not recover following chemotherapy treatment. In contrast, when cancer cells exhibit only autophagy and limited Type II cell death, they are chemoresistant and recover following drug withdrawal.

METHODS

MicroRNA (miRNA) expression profiling of an oesophageal cancer cell line panel was used to identify miRNAs that were important in the regulation of apoptosis and autophagy. The effects of miRNA overexpression on cell death mechanisms and recovery were assessed in the chemoresistant (autophagy inducing) KYSE450 oesophageal cancer cells.

RESULTS

MiR-193b was the most differentially expressed miRNA between the chemosensitive and chemoresistant cell lines with higher expression in chemosensitive apoptosis inducing cell lines. Colony formation assays showed that overexpression of miR-193b significantly impedes the ability of KYSE450 cells to recover following 5-fluorouracil (5-FU) treatment. The critical mRNA targets of miR-193b are unknown but target prediction and siRNA data analysis suggest that it may mediate some of its effects through stathmin 1 regulation. Apoptosis was not involved in the enhanced cytotoxicity. Overexpression of miR-193b in these cells induced autophagic flux and non-apoptotic cell death.

CONCLUSION

These results highlight the importance of miR-193b in determining oesophageal cancer cell viability and demonstrate an enhancement of chemotoxicity that is independent of apoptosis induction.

Anti-STMN1 therapy improves sensitivity to antimicrotubule drugs in esophageal squamous cell carcinoma

Stathmin (STMN1) regulates microtubule dynamics by promoting depolymerization of microtubules and/or preventing polymerization of tubulin heterodimers. Several studies have shown that overexpression of STMN1 has been linked to chemoresistance of paclitaxel and vinblastine in tumor cells. This study aimed to investigate the effects of STMN1 silencing on chemosensitivities of paclitaxel or vinblastine in esophageal squamous cell carcinoma (ESCC). Immunocytochemistry and immunofluorescence assays showed that STMN1 gene was highly expressed in Eca109 and TE-1 cells. We demonstrated that lentiviral-mediated STMN1 short hairpin RNA (shRNA) specifically and efficiently downregulated STMN1 expression in Eca109 and TE-1 cells. The sensitivity of STMN1-silencing shRNA-transfected Eca109 and TE-1 cells increased 191.4- and 179.3-fold to paclitaxel, and 21.3- and 28.4-fold to vincristine, respectively. Flow cytometry and mitotic index assays showed that knockdown of STMN1 in Eca109 and TE-1 cells led to cell cycle arrest in G2/M phase. After treatment with paclitaxel or vincristine, STMN1-silencing shRNA-transfected Eca109 and TE-1 cells were more likely to enter G2 but less likely to enter mitosis than control cells. Therefore, these data suggests that silencing STMN1 gene could increase sensitivity of ESCC to paclitaxel and vincristine through G2/M phase block.