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

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.

Influence of stathmin 1 (STMN1) expression on neoangiogenesis in colorectal adenocarcinoma

Stathmin1 is a microtubular regulatory protein. The expression disorders of this protein result in significant changes in cell migration, invasion, adhesion and colony formation in many malignant tumors. The aim of our research was to investigate the effects of Stathmin1 expression on neoangiogenesis in colorectal adenocarcinoma. Biopsy material that was obtained by the resection of colorectal carcinoma was used. The experimental group consisted of operative biopsies of colorectal cancer (n = 72), and the control group (n = 72) consisted of biopsies of adjacent non-tumor colon tissue. The biopsy material was taken from an operative preparation submitted to the Department of Pathology. After histopathological treatment, classical Hematoxylin- Eosin and immunohistochemical ABC methods with anti-Stathmin1, anti-VEGF and anti CD105 antibodies were applied on 4 µm thick sections. High expression of Stathmin1 is associated with severe (91.9%) and moderate (8.1%) expression of VEGF in a significantly high number of cases. This relation is defined by a highly significant correlation coefficient (r = 0.768; p = 0.000). High expression of Stathmin1 is associated with a high microvascular density index (mvdIDX) in a significant number of cases (73.0%) while low expression of Stathmin1 is in relation with low mvdIDX in a significant 73.7% of cases. This relationship is also defined by a highly significant correlation coefficient (r = 0.566; p = 0.000). ROC analysis showed that the sensitivity for Stathmin1 was 97.4% and the specificity was 91.4%. Based on Stathmin1 expression, it is possible to differentiate patients with increased risk for metastatic disease. The highly significant association of Stathmin1 expression with VEGF expression and microvascular density (MVD) suggests that Stathmin1 may be a serious candidate for therapeutic target.

A review on the role of tau and stathmin in gastric cancer metastasis

Gastric cancer is resistant to chemotherapy, especially in the later stages. The prevalence of gastric cancer increases after the age of 40, and its peak is in the 7th decade of life. The proteins tau (tubulin associated unit) and stathmin are overexpressed in gastric cancer and contribute to the progression of the disease by increasing cancer cell proliferation, invasion, and inducing drug resistance. This review summarizes the current knowledge on the expression of tau protein and stathmin in gastric cancer and their roles in drug resistance. Medline and PubMed databases were searched from 1990 till February 2021 for the terms "tau protein", "stathmin", and "gastric cancer." Two reviewers screened all articles and assessed prognostic studies on the role of tau and stathmin proteins in gastric cancer progression. Collectively, studies reported that both proteins are expressed at different concentrations in gastric cancer and could be significant molecular biomarkers for prognosis. Both proteins could be good candidates for targeted therapy of gastric cancer and are associated with resistance to taxanes.

The microRNA-210-Stathmin1 Axis Decreases Cell Stiffness to Facilitate the Invasiveness of Colorectal Cancer Stem Cells

Simple Summary

Metastasis of tumor cells is the leading cause of death in cancer patients. Concurrent therapy with surgical removal of primary and metastatic lesions is the main approach for cancer therapy. Currently, therapeutic resistant properties of cancer stem cells (CSCs) are known to drive malignant cancer progression, including metastasis. Our study aimed to identify molecular tools dedicated to the detection and treatment of CSCs. We confirmed that microRNA-210-3p (miR-210) was upregulated in colorectal stem-like cancer cells, which targeted stathmin1 (STMN1), to decrease cell elasticity for increasing mobility. We envision that strategies for softening cellular elasticity will reduce the onset of CSC-orientated metastasis.

Abstract

Cell migration is critical for regional dissemination and distal metastasis of cancer cells, which remain the major causes of poor prognosis and death in patients with colorectal cancer (CRC). Although cytoskeletal dynamics and cellular deformability contribute to the migration of cancer cells and metastasis, the mechanisms governing the migratory ability of cancer stem cells (CSCs), a nongenetic source of tumor heterogeneity, are unclear. Here, we expanded colorectal CSCs (CRCSCs) as colonospheres and showed that CRCSCs exhibited higher cell motility in transwell migration assays and 3D invasion assays and greater deformability in particle tracking microrheology than did their parental CRC cells. Mechanistically, in CRCSCs, microRNA-210-3p (miR-210) targeted stathmin1 (STMN1), which is known for inducing microtubule destabilization, to decrease cell elasticity in order to facilitate cell motility without affecting the epithelial–mesenchymal transition (EMT) status. Clinically, the miR-210-STMN1 axis was activated in CRC patients with liver metastasis and correlated with a worse clinical outcome. This study elucidates a miRNA-oriented mechanism regulating the deformability of CRCSCs beyond the EMT process.

Aberrantly high activation of a FoxM1-STMN1 axis contributes to progression and tumorigenesis in FoxM1-driven cancers

Fork-head box protein M1 (FoxM1) is a transcriptional factor which plays critical roles in cancer development and progression. However, the general regulatory mechanism of FoxM1 is still limited. STMN1 is a microtubule-binding protein which can inhibit the assembly of microtubule dimer or promote depolymerization of microtubules. It was reported as a major responsive factor of paclitaxel resistance for clinical chemotherapy of tumor patients. But the function of abnormally high level of STMN1 and its regulation mechanism in cancer cells remain unclear. In this study, we used public database and tissue microarrays to analyze the expression pattern of FoxM1 and STMN1 and found a strong positive correlation between FoxM1 and STMN1 in multiple types of cancer. Lentivirus-mediated FoxM1/STMN1-knockdown cell lines were established to study the function of FoxM1/STMN1 by performing cell viability assay, plate clone formation assay, soft agar assay in vitro and xenograft mouse model in vivo. Our results showed that FoxM1 promotes cell proliferation by upregulating STMN1. Further ChIP assay showed that FoxM1 upregulates STMN1 in a transcriptional level. Prognostic analysis showed that a high level of FoxM1 and STMN1 is related to poor prognosis in solid tumors. Moreover, a high co-expression of FoxM1 and STMN1 has a more significant correlation with poor prognosis. Our findings suggest that a general FoxM1-STMN1 axis contributes to cell proliferation and tumorigenesis in hepatocellular carcinoma, gastric cancer and colorectal cancer. The combination of FoxM1 and STMN1 can be a more precise biomarker for prognostic prediction.

Omics technologies for improved diagnosis and treatment of colorectal cancer: Technical advancement and major perspectives

Colorectal cancer (CRC) ranks third among the most commonly occurring cancers worldwide, and it causes half a million deaths annually. Alongside mechanistic study for CRC detection and treatment by conventional techniques, new technologies have been developed to study CRC. These technologies include genomics, transcriptomics, proteomics, and metabolomics which elucidate DNA markers, RNA transcripts, protein and, metabolites produced inside the colon and rectum part of the gut. All these approaches form the omics arena, which presents a remarkable opportunity for the discovery of novel prognostic, diagnostic and therapeutic biomarkers and also delineate the underlying mechanism of CRC causation, which may further help in devising treatment strategies. This review also mentions the latest developments in metagenomics and culturomics as emerging evidence suggests that metagenomics of gut microbiota has profound implications in the causation, prognosis, and treatment of CRC. A majority of bacteria cannot be studied as they remain unculturable, so culturomics has also been strengthened to develop culture conditions suitable for the growth of unculturable bacteria and identify unknown bacteria. The overall purpose of this review is to succinctly evaluate the application of omics technologies in colorectal cancer research for improving the diagnosis and treatment strategies.

LncRNA LINC01116 Promotes the Development of Colorectal Cancer by Targeting miR-9-5p/STMN1

PURPOSE

The aim was to research the role of LINC01116 in the prognosis of colorectal cancer (CRC) patients and development of colorectal cancer cells.

METHODS

In total 62 colorectal cancer patient tissues and human CRC cell lines (OUMS23, SW116, SW480 and LOVO) were obtained for this study. SiLINC01116, miR-9-5p mimic, LINC01116, oe-STMN1 and their controls were transfected. The qRT-PCR method and Western blot were used to detect the levels of LINC01116, miR-9-5p and STMN1 in tissues and cells. CCK8 assay and flow cytometry were processed for proliferation and apoptosis, respectively. Transwell assay was undertaken to verify invasion and migration. Luciferase assay and pull down assay were processed to confirm the binding relationship among LINC01116, miR-9-5p and STMN1. Immunohistochemistry assay also detected the expression of STMN1. Kaplan-Meier survival curve was used to analyze patient survival rate. Pearson correlation analysis was used to evaluate the regulatory relationship between LINC01116, miR-9-5p and STMN1 in tissues.

RESULTS

LINC01116 was expressed higher in CRC tissues and cells. Patients with higher expression of LINC01116 had worse prognosis. Knockdown of LINC01116 suppressed development of CRC cell. LINC01116 negatively regulated miR-9-5p, while MiR-9-5p was negatively related to STMN1. miR-9-5p mimic could rescue the effect of LINC01116, inhibit migration and invasion, and improve apoptosis of CRC cells. Oe-STMN1 could also rescue the effect of miR-9-5p on the development of colorectal cancer.

CONCLUSION

LINC01116 promoted the development of colorectal cancer via modulating miR-9-5p/STMN1 axis.

The ZIP6/ZIP10 heteromer is essential for the zinc-mediated trigger of mitosis

Zinc has been known to be essential for cell division for over 40 years but the molecular pathways involved remain elusive. Cellular zinc import across biological membranes necessitates the help of zinc transporters such as the SLC39A family of ZIP transporters. We have discovered a molecular process that explains why zinc is required for cell division, involving two highly regulated zinc transporters, as a heteromer of ZIP6 and ZIP10, providing the means of cellular zinc entry at a specific time of the cell cycle that initiates a pathway resulting in the onset of mitosis. Crucially, when the zinc influx across this heteromer is blocked by ZIP6 or ZIP10 specific antibodies, there is no evidence of mitosis, confirming the requirement for zinc influx as a trigger of mitosis. The zinc that influxes into cells to trigger mitosis additionally changes the phosphorylation state of STAT3 converting it from a transcription factor to a protein that complexes with this heteromer and pS³⁸Stathmin, the form allowing microtubule rearrangement as required in mitosis. This discovery now explains the specific cellular role of ZIP6 and ZIP10 and how they have special importance in the mitosis process compared to other ZIP transporter family members. This finding offers new therapeutic opportunities for inhibition of cell division in the many proliferative diseases that exist, such as cancer.

Stathmin guides personalized therapy in oral squamous cell carcinoma

The survival benefit from docetaxel, cisplatin and 5‐fluorouracil (TPF) induction chemotherapy in oral squamous cell carcinoma (OSCC) patients is not satisfactory. Previously, we identified that stathmin, a microtubule‐destabilizing protein, is overexpressed in OSCC. Here, we further investigated its role as a biomarker that impacts on OSCC chemosensitivity. We analyzed the predictive value of stathmin on TPF induction chemotherapy and its impact on OSCC cell chemosensitivity. Then, we further investigated the therapeutic effects of the combination therapy of TPF chemotherapy and PI3K‐AKT‐mTOR inhibitors in vitro and in vivo. We found that OSCC patients with low stathmin expression benefited from TPF induction chemotherapy, while OSCC patients with high stathmin expression could not benefit from TPF induction chemotherapy. Stathmin overexpression promoted cellular proliferation and decreased OSCC cell sensitivity to TPF treatment. In addition, inhibition of the PI3K‐AKT‐mTOR signaling pathway decreased stathmin expression and phosphorylation. The combination therapy of TPF chemotherapy and PI3K‐AKT‐mTOR inhibitors exhibited a potent antitumor effect both in vitro and in vivo. Therefore, stathmin can be used as a predictive biomarker for TPF induction chemotherapy and a combination therapy regimen based on stathmin expression might improve the survival of OSCC patients.

Label-Free Quantitative Phosphoproteomics Reveals Regulation of Vasodilator-Stimulated Phosphoprotein upon Stathmin-1 Silencing in a Pair of Isogenic Colorectal Cancer Cell Lines

In this communication, we present the phosphoproteome changes in an isogenic pair of colorectal cancer cell lines, viz., the poorly metastatic HCT-116 and the highly metastatic derivative E1, upon stathmin-1 (STMN1) knockdown. The aim was to better understand how the alterations of the phosphoproteins in these cells are involved in cancer metastasis. After the phosphopeptides were enriched using the TiO₂ HAMMOC approach, comparative proteomics analysis was carried out using sequential window acquisition of all theoretical mass spectra-MS. Following bioinformatics analysis using MarkerView and OneOmics platforms, we identified a list of regulated phosphoproteins that may play a potential role in signaling, maintenance of cytoskeletal structure, and focal adhesion. Among these phosphoproteins, was the actin cytoskeleton regulator protein, vasodilator-stimulated phosphoprotein (VASP), where its change in phosphorylation status was found to be concomitant with STMN1-associated roles in metastasis. We further showed that silencing of stathmin-1 altered the expression, subcellular localization and phosphorylation status of VASP, which suggested that it might be associated with remodeling of the cell cytoskeleton in colorectal cancer metastasis.

A novel rapid quantitative method reveals stathmin-1 as a promising marker for esophageal squamous cell carcinoma

Stathmin‐1 is a microtubule depolymerization protein that regulates cell division, growth, migration, and invasion. Overexpression of stathmin‐1 has been observed to be associated with metastasis, poor prognosis, and chemoresistance in various human cancers. Our previous studies found that serum stathmin‐1 was significantly elevated in patients with esophageal squamous cell carcinoma (ESCC) by ELISAs. Here, we constructed high‐affinity monoclonal antibodies and then developed a competitive AlphaLISA for rapid, accurate quantitation of stathmin‐1 in serum. Compared to ELISA, our homogeneous AlphaLISA showed better sensitivity and accuracy, a lower limit of detection, and a wider linear range. The measurements of nearly 1000 clinical samples showed that serum stathmin‐1 level increased dramatically in patients with squamous cell carcinoma (SCC), especially in ESCC, with a sensitivity and a specificity of 81% and 94%, respectively. Even for early stage ESCC, stathmin‐1 achieved an area under the receiver operating characteristic curve (AUC) of 0.88. Meanwhile, raised concentrations of stathmin‐1 were associated with lymph node metastasis and advanced cancer stage. Notably, various types of SCC showed significantly higher AUCs in serum stathmin‐1 detection compared to adenocarcinoma. Furthermore, we confirmed that stathmin‐1 was enriched in the oncogenic exosomes, which can explain the reason why it enters into the blood to serve as a tumor surrogate. In conclusion, this large‐scale and systematic study of serum stathmin‐1 measured by our newly established AlphaLISA showed that stathmin‐1 is a very promising diagnostic and predictive marker for SCC in the clinic, especially for ESCC.

STMN1 is Overexpressed in Adrenocortical Carcinoma and Promotes a More Aggressive Phenotype In Vitro

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with a poor prognosis and few therapeutic options. Stathmin1 (STMN1) is a cytosolic protein involved in microtubule dynamics through inhibition of tubulin polymerization and promotion of microtubule depolymerization, which has been implicated in carcinogenesis and aggressive behavior in multiple epithelial malignancies. We aimed to evaluate expression of STMN1 in ACC and to elucidate how this may contribute to its malignant phenotype.

METHODS

STMN1 was identified by RNA sequencing as a highly differentially expressed gene in human ACC samples compared with benign adrenal tumors. Expression was confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemical (IHC) staining of a tissue microarray (TMA) from two independent cohorts. The biologic relevance of STMN1 was investigated in NCI-H295R cells by lentivirus-mediated silencing.

RESULTS

Differential gene expression demonstrated an eightfold increase in STMN1 messenger RNA (mRNA) in malignant compared with benign adrenal tissue. IHC showed significantly higher expression of STMN1 protein in ACC compared with normal and benign tissues. STMN1 knockdown in an ACC cell line resulted in decreased cell viability, cell-cycle arrest at G₀/G₁, and increased apoptosis in serum-starved conditions compared with scramble short hairpin RNA (shRNA) controls. STMN1 knockdown also decreased migration, invasion, and anchorage-independent growth compared with controls.

CONCLUSIONS

STMN1 is overexpressed in human ACC samples, and knockdown of this target in vitro resulted in a less aggressive phenotype of ACC, particularly under serum-starved conditions. Further study is needed to investigate the feasibility of interfering with STMN1 as a potential therapeutic target.

Stathmin/Op18 depletion induces genomic instability and leads to premature senescence in human normal fibroblasts

Stathmin/oncoprotein18 regulates microtubule dynamics and participates in mitotic entry and exit. We isolated stathmin as a physically interacting partner of KIFC1, a minus-end-directed kinesin functioning in bipolar spindle formation and maintenance. We found that stathmin depletion leads to multipolar spindle formation in IMR-90 normal human fibroblasts. Stathmin-depleted IMR-90 cells showed early mitotic delay but managed to undergo chromosome segregation by forming multiple poles or pseudo-bipoles. Consistent with these observations, lagging chromosomes, and micronuclei were elevated in stathmin-depleted IMR-90 cells, demonstrating that stathmin is essential for maintaining genomic stability during mitosis in human cells. Genomic instability induced by stathmin depletion led to premature senescence without any indication of cell death in normal IMR-90 cells. Double knock-down of both stathmin and p53 also did not induce cell death in IMR-90 cells, while the stathmin knock-down triggered apoptosis in p53-proficient human lung adenocarcinoma cells. Our results suggest that stathmin is essential in bipolar spindle formation to maintain genomic stability during mitosis, and the depletion of stathmin prevents the initiation of chromosome instability by inducing senescence in human normal fibroblasts.

Activation of an AKT/FOXM1/STMN1 pathway drives resistance to tyrosine kinase inhibitors in lung cancer

Background:

Tyrosine kinase inhibitors (TKIs) have demonstrated clinical benefits in the treatment of several tumour types. However, the emergence of TKI resistance restricts the therapeutic effect. This study uses non-small cell lung cancer (NSCLC) to explore the mechanisms contributing to TKI resistance in tumours.

Methods:

Biological phenotypes and RNA microarray expression data were analysed in NSCLC cells with and without TKI pretreatment. Specific inhibitors and siRNAs were used to validate the direct involvement of an AKT/FOXM1/STMN1 pathway in TKI resistance. Patients’ tissues were analysed to explore the clinical importance of FOXM1 and STMN1.

Results:

In vitro and in vivo studies showed that TKIs induced the enrichment of cancer stem cells (CSC), promoted epithelial to mesenchymal transition (EMT), and conferred multidrug resistance on NSCLC cells in a cell type- and TKI class-dependent manner. Mechanistically, TKIs activated an AKT/FOXM1/STMN1 pathway. The crucial role of this pathway in TKI-induced enrichment of CSC and drug resistance was verified by silencing FOXM1 and STMN1 or blocking the AKT pathway. Additionally, overexpression of STMN1 was associated with upregulation of FOXM1 in advanced NSCLC patients, and STMN1/FOXM1 upregulation predicted a poor outcome.

Conclusions:

Our findings elucidate an additional common mechanism for TKI resistance and provide a promising therapeutic target for reversing TKI resistance in NSCLC.

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.

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.

Integrative analysis of the colorectal cancer proteome: potential clinical impact

INTRODUCTION

Colorectal cancer (CRC) is one of the common types of cancer that affects a significant proportion of the population and is a major contributor to cancer related mortality. The relatively poor survival rate of CRC could be improved through the identification of clinically useful biomarkers. Areas covered: This review highlights the need for biomarkers and discusses recent proteomics discoveries in the aspects of CRC clinical practice including diagnosis, prognosis, therapy, screening and molecular pathological epidemiology (MPE). Studies have been evaluated in relation to biomarker target, methodology, sample selection, limitations, and potential impact. Finally, the progress in proteomic approaches is briefly discussed and the main difficulties facing the translation of proteomics biomarkers into the clinical practice are highlighted. Expert commentary: The establishment of specific guidelines, best practice recommendations and the improvement in proteomic strategies will significantly improve the prospects for developing clinically useful biomarkers.

Stathmin1 increases radioresistance by enhancing autophagy in non-small-cell lung cancer cells

Radioresistance has been demonstrated to be involved in the poor prognosis of patients with non-small-cell lung cancer (NSCLC). However, the underlying mechanism remains largely unclear. Investigation on special therapeutic targets associated with radioresistance shows promises for the enhancement of clinical radiotherapy effect toward NSCLC. This study aimed to reveal the role of Stathmin1 (STMN1) in radioresistance in NSCLC as well as the underlying mechanism. Our data showed that the protein levels of STMN1 were significantly upregulated in NSCLC cells subjected to radiation, accompanied with the activation of autophagy. Knockdown of STMN1 expression enhanced the sensitivity of NSCLC cells to X-ray, and the radiation-induced autophagy was also inhibited. Molecular mechanism investigation showed that knockdown of STMN1 expression upregulated the activity of phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway in NSCLC cells. Moreover, the activation of PI3K/mTOR signaling showed an inhibitory effect on the autophagy and radioresistance induced by STMN1 in NSCLC cells. In addition, luciferase reporter assay data indicated that STMN1 was a direct target gene of miR-101, which had been reported to be an inhibitor of autophagy. Based on these data, we suggest that as a target gene of miR-101, STMN1 promotes the radioresistance by induction of autophagy through PI3K/mTOR signaling pathway in NSCLC. Therefore, STMN1 may become a potential therapeutic target for NSCLC radiotherapy.

Novel indolyl-chalcones target stathmin to induce cancer cell death

Efficacy of current therapies for advanced and metastatic cancers remains a challenge in clinical practice. We investigated the anti-cancer potency of 3 novel indoly-chalcones (CITs). Our results indicated the lead molecule CIT-026 (Formula = C20H16FNO) induced cell death in prostate and lung cancer cell lines at sub-micromolar concentration. CITs (CIT-026, CIT-214, CIT-223) lead to microtubule destabilization, cell death and low cell proliferation, which in part was dependent on stathmin (STMN1) expression. Knockdown of STMN1 with siRNA against STMN1 in part restored viability of cancer cells in response to CITs. Further, CIT-026 and CIT-223 blocked cancer cell invasion through matrigel-coated chambers. Mechanistically, CITs inhibited phosphorylation of STMN1 leading to STMN1 accumulation and mitotic catastrophe. In summary, we have synthetized novel anti-cancer CIT molecules and defined their mechanism of action in vitro.

Loss of miR-223 and JNK Signaling Contribute to Elevated Stathmin in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is often fatal, and studies have revealed that aberrant miRNAs contribute to MPM development and aggressiveness. Here, a screen of miRNAs identified reduced levels of miR-223 in MPM patient specimens. Interestingly, miR-223 targets Stathmin (STMN1), a microtubule regulator that has been associated with MPM. However, whether miR-223 regulates STMN1 in MPM and the functions of miR-223 and STMN1 in this disease are yet to be determined. STMN1 is also regulated by c-Jun N-terminal kinase (JNK) signaling, but whether this occurs in MPM and whether miR-223 plays a role are unknown. The relationship between STMN1, miR-223, and JNK was assessed using MPM cell lines, cells from pleural effusions, and MPM tissue. Evidence indicates that miR-223 is decreased in all MPM tissue compared with normal/healthy tissue. Conversely, STMN1 expression was higher in MPM cell lines when compared with primary mesothelial cell controls. Following overexpression of miR-223 in MPM cell lines, STMN1 levels were reduced, cell motility was inhibited, and tubulin acetylation induced. Knockdown of STMN1 using siRNAs led to inhibition of MPM cell proliferation and motility. Finally, miR-223 levels increased while STMN1 was reduced following the re-expression of the JNK isoforms in JNK-null murine embryonic fibroblasts, and STMN1 was reduced in MPM cell lines following the activation of JNK signaling.

IMPLICATIONS

miR-223 regulates STMN1 in MPM, and both are in turn regulated by the JNK signaling pathway. As such, miR-223 and STMN1 play an important role in regulating MPM cell motility and may be therapeutic targets.