Stathmin 1: a novel therapeutic target for anticancer activity

The relationship between stathmin-2 level and metabolic parameters in newly diagnosed type 2 diabetes mellitus patients

BACKGROUND

Stathmin is a phosphoprotein that plays a role in intercellular and intracellular signaling, inflammation, and differentiation. Our aim was to evaluate the stathmin-2 level and its relationship with the metabolic parameters of newly diagnosed type 2 diabetes mellitus (nT2DM) patients.

MATERIAL AND METHOD

This case-control study included 76 patients with nT2DM and 76 healthy individuals with a normal oral glucose tolerance test who were matched for body mass index (BMI), age, and gender. In addition to laboratory and anthropometric measurements related to type 2 diabetes mellitus (T2DM), stathmin-2 levels were determined using an enzyme-linked immunosorbent assay.

RESULTS

We observed significantly higher circulating stathmin-2 levels in subjects with T2DM compared to the control group (6.39±1.60 ng/mL and 4.66±0.80 ng/mL, p<0.0001). In patients with metabolic syndrome, circulating stathmin-2 levels were significantly elevated compared to those without metabolic syndrome in both the T2DM and control groups (T2DM: 7.16±1.24 vs 5.06±1.24 ng/mL, p<0.001; Control: 3.84±1.40 vs 3.82±1.40 ng/mL). In both groups, we observed a positive correlation between stathmin-2 levels and BMI and circumference. Moreover, stathmin-2 showed a positive correlation with high-sensitivity C-reactive protein (hs-CRP), homeostatic model assessment of insulin resistance, insulin, fasting blood glucose, hemoglobin A1c, BMI, low-density lipoprotein cholesterol, and total cholesterol. A negative correlation was observed with stathmin-2 and high-density lipoprotein cholesterol. Stathmin-2 did not show any correlation with age, triglyceride, and lactate dehydrogenase.

CONCLUSIONS

Stathmin-2 levels were found to be elevated in patients with nT2DM and exhibited positive correlations with hyperinsulinaemia, hyperglycaemia, HOMO-IR and hs-CRP levels. These results indicate that stathmin-2 may play a role in T2DM pathogenesis.

Deciphering the Molecular Mechanisms behind Drug Resistance in Ovarian Cancer to Unlock Efficient Treatment Options

Ovarian cancer is a highly lethal form of gynecological cancer. This disease often goes undetected until advanced stages, resulting in high morbidity and mortality rates. Unfortunately, many patients experience relapse and succumb to the disease due to the emergence of drug resistance that significantly limits the effectiveness of currently available oncological treatments. Here, we discuss the molecular mechanisms responsible for resistance to carboplatin, paclitaxel, polyadenosine diphosphate ribose polymerase inhibitors, and bevacizumab in ovarian cancer. We present a detailed analysis of the most extensively investigated resistance mechanisms, including drug inactivation, drug target alterations, enhanced drug efflux pumps, increased DNA damage repair capacity, and reduced drug absorption/accumulation. The in-depth understanding of the molecular mechanisms associated with drug resistance is crucial to unveil new biomarkers capable of predicting and monitoring the kinetics during disease progression and discovering new therapeutic targets.

EFNB1 levels determine distinct drug response patterns guiding precision therapy for B-cell neoplasms

The multi-omics data has greatly improved the molecular diagnosis of B-cell neoplasms, but there is still a lack of predictive biomarkers to guide precision therapy. Here, we analyzed publicly available data and found that B-cell neoplasm cell lines with different levels of EFNB1 had distinctive drug response patterns of inhibitors targeting SRC/PI3K/AKT. Overexpression of EFNB1 promoted phosphorylation of key proteins in drug response, such as SRC and STMN1, conferring sensitivity to SRC inhibitor and cytotoxic drugs. EFNB1 phosphorylation signaling network was significantly associated with the prognosis of GCB-DLBCL patients. Moreover, EFNB1 levels were correlated with cell of origin (COO) scores, suggesting that EFNB1 is a quantitative indicator of cell differentiation. Ultimately, we proposed a model for the stratification of human B-cell malignancies and the implementation of targeted therapies based on EFNB1 levels. Our findings highlight that EFNB1 level is a promising biomarker for predicting drug response, COO and prognosis.

High Tumoral STMN1 Expression Is Associated with Malignant Potential and Poor Prognosis in Patients with Neuroblastoma

BACKGROUND

Stathmin 1 (STMN1), a marker for immature neurons and tumors, controls microtubule dynamics by destabilizing tubulin. It plays an essential role in cancer progression and indicates poor prognosis in several cancers. This potential protein has not been clarified in clinical patients with neuroblastoma. Therefore, this study aimed to assess the clinical significance and STMN1 function in neuroblastoma with and without MYCN amplification.

METHODS

Using immunohistochemical staining, STMN1 expression was examined in 81 neuroblastoma samples. Functional analysis revealed the association among STMN1 suppression, cellular viability, and endogenous or exogenous MYCN expression in neuroblastoma cell lines.

RESULT

High levels of STMN1 expression were associated with malignant potential, proliferation potency, and poor prognosis in neuroblastoma. STMN1 expression was an independent prognostic factor in patients with neuroblastoma. Furthermore, STMN1 knockdown inhibited neuroblastoma cell growth regardless of endogenous and exogenous MYCN overexpression.

CONCLUSION

Our data suggest that assessing STMN1 expression in neuroblastoma could be a powerful indicator of prognosis and that STMN1 might be a promising therapeutic candidate against refractory neuroblastoma with and without MYCN amplification.

Long Noncoding RNAs in Taxane Resistance of Breast Cancer

Breast cancer is a common cancer in women and a leading cause of mortality. With the early diagnosis and development of therapeutic drugs, the prognosis of breast cancer has markedly improved. Chemotherapy is one of the predominant strategies for the treatment of breast cancer. Taxanes, including paclitaxel and docetaxel, are widely used in the treatment of breast cancer and remarkably decrease the risk of death and recurrence. However, taxane resistance caused by multiple factors significantly impacts the effect of the drug and leads to poor prognosis. Long noncoding RNAs (lncRNAs) have been shown to play a significant role in critical cellular processes, and a number of studies have illustrated that lncRNAs play vital roles in taxane resistance. In this review, we systematically summarize the mechanisms of taxane resistance in breast cancer and the functions of lncRNAs in taxane resistance in breast cancer. The findings provide insight into the role of lncRNAs in taxane resistance and suggest that lncRNAs may be used to develop therapeutic targets to prevent or reverse taxane resistance in patients with breast cancer.

PEG-4000 formed polymeric nanoparticles loaded with cetuximab downregulate p21 &stathmin-1 gene expression in cancer cell lines

Cetuximab (CTX) is known to have cytotoxic effects on several human cancer cells in vitro; however, as CTX is poorly water soluble, there is a need for improved formulations can reach cancer cells at high concentrations with low side effects. We developed (PEG-4000) polymeric nanoparticles (PEGNPs) loaded with CTX and evaluated their in vitro cytotoxicity and anticancer properties against human lung (A549) and breast (MCF-7) cancer cells. CTX-PEGNPs were formulated using the solvent evaporation technique, and their morphological properties were evaluated. Further, the effects of CTX-PEGNPs on cell viability using the MTT assay and perform gene expression analysis, DNA fragmentation measurements, and the comet assay. CTX-PEGNP showed uniformly dispersed NPs of nano-size range (253.7 ± 0.3 nm), and low polydispersity index (0.16) indicating the stability and uniformity of NPs. Further, the zeta potential of the preparations was -17.0 ± 1.8 mv. DSC and FTIR confirmed the entrapping of CTX in NPs. The results showed IC₅₀ values of 2.26 μg/mL and 1.83 μg/mL for free CTX and CTX-PEGNPs on the A549 cancer cell line, respectively. Moreover, CTX-PEGNPs had a lower IC₅₀ of 1.12 μg/mL in MCF-7 cells than that of free CTX (2.28 μg/mL). The expression levels of p21 and stathmin-1 were significantly decreased in both cell lines treated with CTX-PEGNPs compared to CTX alone. The CTX-PEGNP-treated cells also showed increased DNA fragmentation rates in both cancer cell lines compared with CTX alone. The results indicated that CTX-PEGNP was an improved formulation than CTX alone to induce apoptosis and DNA damage and inhibit cell proliferation through the downregulation of P21 and stathmin-1 expression.

Overexpression of Stathmin 1 Predicts Poor Prognosis and Promotes Cancer Cell Proliferation and Migration in Ovarian Cancer

Purpose

The aim of this study was to investigate the expression of stathmin 1 (STMN1) in ovarian cancer and its effect on prognosis. The effect and mechanism of STMN1 on the proliferation and migration of ovarian cancer cells were also investigated.

Methods

Expression of STMN1 was measured by immunohistochemical staining in ovarian cancer tissues. The effects of STMN1 on the proliferation and migration capacity of ovarian cancer were evaluated using Cell Counting Kit-8 (CCK-8) assays, colony formation assays, immunofluorescence staining, wound healing assays, and Transwell assays. Transcription factors were predicted by bioinformatic analysis of TCGA database.

Results

STMN1 was upregulated in ovarian cancer tissues as compared to paracancerous tissues and associated with shorter overall survival. STMN1 expression significantly correlated with FIGO staging and tumor differentiation (P < 0.05). Furthermore, STMN1 promoted proliferation and migration in ovarian cancer cell lines. Bioinformatic analysis revealed that STMN1 was potentially regulated by E2F transcription factors. Then, we found that E2F1 regulated the expression of STMN1 and affected proliferation.

Conclusion

STMN1 is overexpressed in ovarian cancer, and its high expression suggests a poor prognosis. STMN1 promotes the proliferation and migration of ovarian cancer and is regulated by E2F1. Thus, STMN1 may serve as a negative prognostic factor and possible target for the treatment of ovarian cancer patients.

Regulation of miRNAs Expression by Mutant p53 Gain of Function in Cancer

The p53 roles have been largely described; among them, cell proliferation and apoptosis control are some of the best studied and understood. Interestingly, the mutations on the six hotspot sites within the region that encodes the DNA-binding domain of p53 give rise to other very different variants. The particular behavior of these variants led to consider p53 mutants as separate oncogene entities; that is, they do not retain wild type functions but acquire new ones, namely Gain-of-function p53 mutants. Furthermore, recent studies have revealed how p53 mutants regulate gene expression and exert oncogenic effects by unbalancing specific microRNAs (miRNAs) levels that provoke epithelial-mesenchymal transition, chemoresistance, and cell survival, among others. In this review, we discuss recent evidence of the crosstalk between miRNAs and mutants of p53, as well as the consequent cellular processes dysregulated.

NTRK1/TrkA Signaling in Neuroblastoma Cells Induces Nuclear Reorganization and Intra-Nuclear Aggregation of Lamin A/C

Simple Summary

Neuroblastoma (NB) accounts for 15% of all cancer-related deaths of children. While the amplification of the Myc-N proto-oncogene (MYCN) is a major driver of aggressive NB, the expression of the neurotrophin receptor, NTRK1/TrkA, has been shown to be associated with an excellent outcome. MYCN downregulates NTRK1 expression, but it is unknown if the molecular effects of NTRK1 signaling also affect MYCN-induced networks. The aim of this study was to decipher NTRK1 signaling using an unbiased proteome and phosphoproteome approach. To this end, we realized inducible ectopic NTRK1 expression in a NB cell line with MYCN amplification and analyzed the proteomic changes upon NTRK1 activation in a time-dependent manner. In line with the phenotypes observed, NTRK1 activation induced markers of neuronal differentiation and cell cycle arrest. Most prominently, NTRK1 upregulated the expression and phosphorylation of the nuclear lamina component Lamin A/C. Moreover, NTRK1 signaling also induced the aggregation of LMNA within nucleic foci, which accompanies differentiation in other cell types.

Abstract

(1) Background: Neuroblastomas (NBs) are the most common extracranial solid tumors of children. The amplification of the Myc-N proto-oncogene (MYCN) is a major driver of NB aggressiveness, while high expression of the neurotrophin receptor NTRK1/TrkA is associated with mild disease courses. The molecular effects of NTRK1 signaling in MYCN-amplified NB, however, are still poorly understood and require elucidation. (2) Methods: Inducible NTRK1 expression was realized in four NB cell lines with (IMR5, NGP) or without MYCN amplification (SKNAS, SH-SY5Y). Proteome and phosphoproteome dynamics upon NTRK1 activation by its ligand, NGF, were analyzed in a time-dependent manner in IMR5 cells. Target validation by immunofluorescence staining and automated image processing was performed using the three other NB cell lines. (3) Results: In total, 230 proteins and 134 single phosphorylated class I phosphosites were found to be significantly regulated upon NTRK1 activation. Among known NTRK1 targets, Stathmin and the neurosecretory protein VGF were recovered. Additionally, we observed the upregulation and phosphorylation of Lamin A/C (LMNA) that accumulated inside nuclear foci. (4) Conclusions: We provide a comprehensive picture of NTRK1-induced proteome and phosphoproteome dynamics. The phosphorylation of LMNA within nucleic aggregates was identified as a prominent feature of NTRK1 signaling independent of the MYCN status of NB cells.

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.

CARMA3 Transcriptional Regulation of STMN1 by NF-κB Promotes Renal Cell Carcinoma Proliferation and Invasion

CARD-containing MAGUK protein 3 (CARMA3) is associated with tumor occurrence and progression. However, the signaling pathways involved in CARMA3 function remain unclear. We aimed to analyze the association between CARMA3 and stathmin (STMN1) through the NF-κB pathway, which is associated with cell proliferation and invasion, in clear cell renal cell carcinoma (ccRCC). We evaluated the effects of CARMA3 and STMN1 expression on cell migration, proliferation, and invasion in various cell lines, and their expression in tissue samples from patients with ccRCC. CARMA3 was highly expressed in ccRCC tissues and cell lines. Moreover, CARMA3 promoted the proliferation and invasion of RCC cells by activating the NF-κB pathway to transcribe STMN1. Stathmin exhibited a consistent profile with CARMA3 in ccRCC tissue, and could be an effector for CARMA3-activated cell proliferation and invasion of ccRCC cells. In summary, CARMA3 may serve as a promising target for ccRCC treatment.

Stathmin dynamics modulate the activity of eribulin in breast cancer cells

Stathmin, a phosphoprotein that modulates microtubule dynamics, is highly expressed in breast cancer cells. Eribulin, a microtubule‐depolymerizing agent, is used to treat patients with advanced breast cancer. However, the detailed mechanisms underlying the action of eribulin during microtubule catastrophe, and the interaction between eribulin and stathmin dynamics, remain unclear. Here, we investigated the role of stathmin in the antiproliferative activity of eribulin in breast cancer cells. Eribulin induced phosphorylation of stathmin in MCF7 and MDA‐MB‐231 cells; this was attenuated by an inhibitor of protein kinase A (H89) and an inhibitor of Ca²⁺/calmodulin‐dependent kinase II (KN62). In addition, expression of phosphorylated stathmin was reduced by the protein phosphatase PP2A activator FTY720 but increased by the PP2A inhibitor okadaic acid. Of note, expression of PP2A subunits in eribulin‐treated cells decreased, although eribulin did not affect the phosphatase activity of recombinant PP2A directly. Furthermore, the antiproliferative effect of eribulin was stronger in stathmin‐overexpressing cells. These results suggest that stathmin dynamics are closely associated with the antiproliferative effects of eribulin and stathmin is a possible biomarker for predicting the therapeutic effects of eribulin in breast cancer patients.

PICT1 is critical for regulating the Rps27a-Mdm2-p53 pathway by microtubule polymerization inhibitor against cervical cancer

In our previous study, it showed that P-3F, a podophyllotoxin derivative, causes the increased level of p53 expression by enhancing p53 stability, resulting from blockage of the Mdm2-p53 feedback loop via nucleolus-to-nucleoplasm translocation of Rps27a in human cervical cancer HeLa cell line. However, the mechanism of regulating Rps27a localization remains to be studied. In the current study, it has been demonstrated that the level of protein interacting with carboxyl terminus 1 (PICT1), originally identified as a tumor suppressor, was decreased in a concentration-dependent manner in response to P-3F, leading to inhibition of human cervical cancer cell lines proliferation. Also remarkably, reduction of serine phosphorylation of STMN1 at position 16 induced by P-3F was required in the downregulation of PICT1, in which p53 activity was likely to be directly involved. Note as well that, PICT1 also played an important role in p53 stability enhancement by inhibiting Mdm2-mediated p53 ubiquitination due to Rps27a translocation from the nucleolus to the nucleoplasm to interact with Mdm2 following treatment with P-3F. Collectively, these findings indicated that P-3F, a microtubule polymerization inhibitor, promotes the decreased level of PICT1 expression, which is critical for regulating the Rps27a-Mdm2-p53 pathway against cervical cancer.

Extracellular Vesicles as a Novel Liquid Biopsy-Based Diagnosis for the Central Nervous System, Head and Neck, Lung, and Gastrointestinal Cancers: Current and Future Perspectives

Simple Summary

To improve clinical outcomes, early diagnosis is mandatory in cancer patients. Several diagnostic approaches have been proposed, however, the main drawback relies on the invasive procedures required. Extracellular vesicles (EVs) are bilayer lipid membrane structures released by almost all cells and transferred to remote sites via the bloodstream. The observation that their cargo reflects the cell of origin has opened a new frontier for non-invasive biomarker discovery in oncology. Moreover, since EVs can be recovered from different body fluids, their impact as a Correctdiagnostic tool has gained particular interest. Hence, in the last decade, several studies using different biological fluids have been performed, showing the valuable contributions of EVs as tumour biomarkers, and their improved diagnostic power when combined with currently available tumour markers. In this review, the most relevant data on the diagnostic relevance of EVs, alone or in combination with the well-established tumour markers, are discussed.

Abstract

Early diagnosis, along with innovative treatment options, are crucial to increase the overall survival of cancer patients. In the last decade, extracellular vesicles (EVs) have gained great interest in biomarker discovery. EVs are bilayer lipid membrane limited structures, released by almost all cell types, including cancer cells. The EV cargo, which consists of RNAs, proteins, DNA, and lipids, directly mirrors the cells of origin. EVs can be recovered from several body fluids, including blood, cerebral spinal fluid (CSF), saliva, and Broncho-Alveolar Lavage Fluid (BALF), by non-invasive or minimally invasive approaches, and are therefore proposed as feasible cancer diagnostic tools. In this review, methodologies for EV isolation and characterization and their impact as diagnostics for the central nervous system, head and neck, lung, and gastrointestinal cancers are outlined. For each of these tumours, recent data on the potential clinical applications of the EV’s unique cargo, alone or in combination with currently available tumour biomarkers, have been deeply discussed.

A Bioinformatics Analysis Identifies the Telomerase Inhibitor MST-312 for Treating High-STMN1-Expressing Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a relatively chemo-resistant tumor. Several multi-kinase inhibitors have been approved for treating advanced HCC. However, most HCC patients are highly refractory to these drugs. Therefore, the development of more effective therapies for advanced HCC patients is urgently needed. Stathmin 1 (STMN1) is an oncoprotein that destabilizes microtubules and promotes cancer cell migration and invasion. In this study, cancer genomics data mining identified STMN1 as a prognosis biomarker and a therapeutic target for HCC. Co-expressed gene analysis indicated that STMN1 expression was positively associated with cell-cycle-related gene expression. Chemical sensitivity profiling of HCC cell lines suggested that High-STMN1-expressing HCC cells were the most sensitive to MST-312 (a telomerase inhibitor). Drug-gene connectivity mapping supported that MST-312 reversed the STMN1-co-expressed gene signature (especially BUB1B, MCM2/5/6, and TTK genes). In vitro experiments validated that MST-312 inhibited HCC cell viability and related protein expression (STMN1, BUB1B, and MCM5). In addition, overexpression of STMN1 enhanced the anticancer activity of MST-312 in HCC cells. Therefore, MST-312 can be used for treating STMN1-high expression HCC.

Taxanes in cancer treatment: Activity, chemoresistance and its overcoming

Since 1984, when paclitaxel was approved by the FDA for the treatment of advanced ovarian carcinoma, taxanes have been widely used as microtubule-targeting antitumor agents. However, their historic classification as antimitotics does not describe all their functions. Indeed, taxanes act in a complex manner, altering multiple cellular oncogenic processes including mitosis, angiogenesis, apoptosis, inflammatory response, and ROS production. On the one hand, identification of the diverse effects of taxanes on oncogenic signaling pathways provides opportunities to apply these cytotoxic drugs in a more rational manner. On the other hand, this may facilitate the development of novel treatment modalities to surmount anticancer drug resistance. In the latter respect, chemoresistance remains a major impediment which limits the efficacy of antitumor chemotherapy. Taxanes have shown impact on key molecular mechanisms including disruption of mitotic spindle, mitosis slippage and inhibition of angiogenesis. Furthermore, there is an emerging contribution of cellular processes including autophagy, oxidative stress, epigenetic alterations and microRNAs deregulation to the acquisition of taxane resistance. Hence, these two lines of findings are currently promoting a more rational and efficacious taxane application as well as development of novel molecular strategies to enhance the efficacy of taxane-based cancer treatment while overcoming drug resistance. This review provides a general and comprehensive picture on the use of taxanes in cancer treatment. In particular, we describe the history of application of taxanes in anticancer therapeutics, the synthesis of the different drugs belonging to this class of cytotoxic compounds, their features and the differences between them. We further dissect the molecular mechanisms of action of taxanes and the molecular basis underlying the onset of taxane resistance. We further delineate the possible modalities to overcome chemoresistance to taxanes, such as increasing drug solubility, delivery and pharmacokinetics, overcoming microtubule alterations or mitotic slippage, inhibiting drug efflux pumps or drug metabolism, targeting redox metabolism, immune response, and other cellular functions.

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.

The impact of transcription inhibition during in vitro maturation on the proteome of bovine oocytes†

Proper oocyte maturation is a prerequisite for successful reproduction and requires the resumption of meiosis to the metaphase II stage (MII). In bovine oocytes, nuclear maturation has been shown to occur in in vitro maturing cumulus-enclosed oocytes (COCs) in the absence of transcription, but their developmental capacity is reduced compared to transcriptionally competent COCs. To assess the impact of transcription during in vitro maturation of bovine COCs on the quantitative oocyte proteome, a holistic nano-LC-MS/MS analysis of germinal vesicle oocytes and MII oocytes matured with or without addition of the transcription inhibitor actinomycin D (ActD) was carried out. Analyzing eight biological replicates for each of the three groups, a total of 2018 proteins was identified. These could be clearly classified into proteins depending or not depending on transcription during oocyte maturation. Proteins whose abundance increased after maturation irrespective of transcription inhibition - and hence independent of transcription - were related to the cell cycle, reflecting the progression of meiosis, and to cellular component organization, which is crucial for cytoplasmic maturation. In contrast, transcription-dependent proteins were associated with cell-cell adhesion and translation. Since a high rate of protein synthesis in oocytes has been shown to correlate with their developmental competence, oocyte maturation in transcriptionally impaired COCs is apparently disturbed. Our experiments reveal that impaired transcription during in vitro maturation of COCs has a substantial effect on specific components of the oocyte proteome, and that transcription is required for specific classes of oocyte proteins predominantly involved in translation.

Role of microRNA/Epithelial-to-Mesenchymal Transition Axis in the Metastasis of Bladder Cancer

Bladder cancer (BC) is the 11th most common diagnosed cancer, and a number of factors including environmental and genetic ones participate in BC development. Metastasis of BC cells into neighboring and distant tissues significantly reduces overall survival of patients with this life-threatening disorder. Recently, studies have focused on revealing molecular pathways involved in metastasis of BC cells, and in this review, we focus on microRNAs (miRNAs) and their regulatory effect on epithelial-to-mesenchymal transition (EMT) mechanisms that can regulate metastasis. EMT is a vital process for migration of BC cells, and inhibition of this mechanism restricts invasion of BC cells. MiRNAs are endogenous non-coding RNAs with 19-24 nucleotides capable of regulating different cellular events, and EMT is one of them. In BC cells, miRNAs are able to both induce and/or inhibit EMT. For regulation of EMT, miRNAs affect different molecular pathways such as transforming growth factor-beta (TGF-β), Snail, Slug, ZEB1/2, CD44, NSBP1, which are, discussed in detail this review. Besides, miRNA/EMT axis can also be regulated by upstream mediators such as lncRNAs, circRNAs and targeted by diverse anti-tumor agents. These topics are also discussed here to reveal diverse molecular pathways involved in migration of BC cells and strategies to target them to develop effective therapeutics.

The values of Transgelin, Stathmin, BCOR and Cyclin-D1 expression in differentiation between Uterine Leiomyosarcoma (ULMS) and Endometrial Stromal Sarcoma (ESS); diagnostic and prognostic implications

Background

Morphologic distinction between uterine leiomyosarcoma (ULMS) and endometrial stromal sarcoma (ESS) alone is not straightforward and has been shown to be challenging especially with poor differentiation, so immunohistochemistry (IHC) is often employed as an adjunct to morphology in uterine sarcoma.

Aim

We aimed to assess the diagnostic utility of Transgelin, Stathmin, BCOR and Cyclin-D1 separately and in-combinations in distinguishing ULMS from ESS, and to evaluate their prognostic value in patients with such sarcoma subtypes.

Material and Methods

We included 44 patients with uterine sarcoma. The diagnostic performances of Transgelin, Stathmin, BCOR and Cyclin-D1 were assessed in samples from all patients using immunohistochemistry.

Results

The combination of Stathmin and Transgelin expression has high sensitivity and specificity for diagnosis of LMS and differentiating it from ESS; 95.5% and associated with poor prognosis in LMS patients.

The combination of BCOR and Cyclin-D1 expression has high sensitivity and specificity for diagnosis of ESS and differentiating it from LMS; 90.9% and 95.5% respectively and associated with poor prognosis in ESS patients. The combination of Stathmin and Transgelin, BCOR and CyclinD1 expression has high sensitivity and specificity for diagnosis of LMS and differentiating it from ESS; 100%.

Conclusion

Combination of Stathmin, Transgelin, BCOR and Cycline-D1 raised the accuracy of differentiation between ULMS and ESS to 100% and has prognostic roles in such sarcomas.

Stathmin expression associates with vascular and immune responses in aggressive breast cancer subgroups

Studies indicate that stathmin expression associates with PI3K activation in breast cancer, suggesting stathmin as a marker for targetable patient subgroups. Here we assessed stathmin in relation to tumour proliferation, vascular and immune responses, BRCA1 germline status, basal-like differentiation, clinico-pathologic features, and survival. Immunohistochemical staining was performed on breast cancers from two series (cohort 1, n = 187; cohort 2, n = 198), and mass spectrometry data from 24 cases and 12 breast cancer cell lines was examined for proteomic profiles. Open databases were also explored (TCGA, METABRIC, Oslo2 Landscape cohort, Cancer Cell Line Encyclopedia). High stathmin expression associated with tumour proliferation, p53 status, basal-like differentiation, BRCA1 genotype, and high-grade histology. These patterns were confirmed using mRNA data. Stathmin mRNA further associated with tumour angiogenesis, immune responses and reduced survival. By logistic regression, stathmin protein independently predicted a BRCA1 genotype (OR 10.0, p = 0.015) among ER negative tumours. Cell line analysis (Connectivity Map) implied PI3K inhibition in tumours with high stathmin. Altogether, our findings indicate that stathmin might be involved in the regulation of tumour angiogenesis and immune responses in breast cancer, in addition to tumour proliferation. Cell data point to potential effects of PI3K inhibition in tumours with high stathmin expression.

Stathmin 1 is highly expressed and associated with survival outcome in malignant adrenocortical tumours

Adrenocortical carcinoma (ACC) is an aggressive endocrine cancer with few molecular predictors of malignancy and survival, especially in paediatric patients. Stathmin 1 (STMN1) regulates microtubule dynamics and has been involved in the malignant phenotype of cancer cells. Recently, it was reported that STMN1 is highly expressed in ACC patients, and STMN1 silencing reduces the clonogenicity and migration of ACC cell lines. However, the prognostic significance of STMN1 and its therapeutic potential remain undefined in ACC. In the present study, STMN1 mRNA levels were significantly higher (p < 0.05) in ACC patients, especially in an advanced stage, and correlated with BUB1B and PINK1 expression, the prognostic-related genes in ACC. In paediatric tumours, high STMN1 expression was observed in both adrenocortical carcinoma and adrenocortical adenoma patients. Among the adult malignant tumours, STMN1 level was an independent predictor of survival outcomes (overall survival: hazard ratio = 6.08, p = 0.002; disease-free survival: hazard ratio = 4.65, p < 0.0001). Paclitaxel, a microtubule-stabilizing drug, reduces the activation of STMN1 and significantly decreases cell migration and invasion in ACC cell lines and ACC cells from secondary cell culture (all p < 0.0001). In summary, STMN1 expression may be of great value to clinical and pathological findings in therapeutic trials and deserves future studies in ACC.

Dexmedetomidine protects PC12 cells from lidocaine-induced cytotoxicity via downregulation of Stathmin 1

Background: Understanding of lidocaine-induced neurotoxicity is not complete, resulting in the unsuccessful treatment in some clinical settings. Dexmedetomidine (DEX) has been shown to alleviate lidocaine-induced neurotoxicity in our previous cell model. However, the rationale for DEX combined with lidocaine to reduce lidocaine-induced neurotoxicity in the clinical setting remains to be further clarified in the detailed molecular mechanism. Methods: In this study, we established a cellular injury model by lidocaine preconditioning. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) proliferation assay kit were used to analyze cell proliferation. Cell apoptosis was measured by flow cytometry and Hoechst 33342 staining. Cell cycle progression was detected by flow cytometry. The protein expression levels were detected by Western blotting and immunofluorescence staining. Results: Our results showed that DEX dose-dependently restored impaired proliferation of PC12 cells induced by lidocaine，as reflected by the increased cell viability and EdU positive cells, which were consistent with the decreased expression of tumor suppressor protein p21 and increased expression of cell cycle-related cyclin D1 and CDK1. In addition, DEX dose-dependently reduced apoptotic PC12 cells induced by lidocaine，as reflected by the decreased expression of apoptosis-related Bax, caspase-3 and caspase-9 and increased expression of anti-apoptotic Bcl-2 compared to the cells only treated with lidocaine. Mechanistically, with gain-or-loss-of-function of STMN1, we showed that DEX-mediated neuroprotection by lidocaine-induced damage is associated with downregulation of STMN1 which might be an upstream molecule involved in regulation of mitochondria death pathway. Conclusion: Our results reveal that DEX is likely to be an effective adjunct to alleviate chronic neurotoxicity induced by lidocaine.

Stathmin-1 Is a Useful Diagnostic Marker for High-Grade Lung Neuroendocrine Tumors

BACKGROUND

Stathmin-1 regulates microtubule dynamics and is associated with malignant phenotypes in non-small cell lung cancer (NSCLC). This study evaluated its diagnostic value for differentiating between NSCLC and high-grade lung neuroendocrine tumor (HGNET).

METHODS

Stathmin-1 protein expression was assessed by immunohistochemistry in 414 NSCLC (305 adenocarcinoma [AD], 102 squamous cell carcinoma [SCC], 7 large-cell carcinoma), 5 typical carcinoid (low-grade lung neuroendocrine tumor), and 34 HGNET (17 small-cell carcinoma [SCLC] and 17 large-cell neuroendocrine carcinoma [LCNEC]) surgical specimens and 57 NSCLC (29 AD and 28 SCC) and 42 HGNET (17 LCNEC and 25 SCLC) biopsy specimens. We also analyzed stathmin-1 mRNA levels in 81 NSCLCs and 26 HGNETs with the use of reverse transcription-polymerase chain reaction.

RESULTS

Among NSCLC samples, we saw high stathmin-1 protein expression in only three ADs, one SCC, and one large-cell carcinoma surgical samples, all five of which showed neuroendocrine characteristics in pathologic re-review; and low or intermediate expression in all five typical carcinoid surgical samples and all 57 NSCLC biopsy samples. In contrast, all HGNET surgical (n = 34) and biopsy (n = 42) samples showed high stathmin-1 expression. In reverse transcription-polymerase chain reaction, stathmin-1 expression was significantly higher in HGNET tissues than in NSCLC tissues (p < 0.001).

CONCLUSIONS

Stathmin-1 expression can help in differentiating NSCLC from HGNET.

Analysis of Protein Expression in Human Cells Cocultured with Porcine Peripheral Blood Mononuclear Cells

OBJECTIVE

Porcine endogenous retroviruses (PERV) involved in pig to human xenotransplantation have raised great concerns because of their ubiquitous nature in pigs and their ability of infecting human cells in vitro. Although no significant cytopathic effect attributed to PERV was evident on PERV-infected human embryonic kidney 293 (HEK293) cells, we did proteomic analysis to investigate the differences of protein profile in order to further characterize the effect of PERV infection.

METHODS

HEK293 cells were cocultured with porcine peripheral blood mononuclear cells (PBMCs). Protein profiles of PERV-infected and -noninfected HEK293 cells were analyzed by two-dimensional gel electrophoresis (2-DE). Protein spots with at least 1.5-fold alteration were identified by high-definition mass spectrometry (HDMS) analysis. Then real-time RT-PCR and Western blotting were performed to validate the proteomic results.

RESULTS

Differential analysis of PERV-infected and -noninfected HEK293 cells by 2-DE revealed ten differentially regulated proteins. The proteins identified by HDMS were involved in various cellular pathways including signal transduction, cell apoptosis, and protein synthesis.

CONCLUSION

The results of this study revealed differentially expressed proteins in HEK293 cells cocultured with porcine PBMCs and implied that these changes were probably induced by PERV infection. These results provide clues and potential links to understanding the molecular effect of the infection by human-tropic PERV.

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.

Expression and phosphorylation of Stathmin 1 indicate poor survival in head and neck squamous cell carcinoma and associate with immune suppression

AIM

Immunohistochemistry was used to detect the expression of Stathmin 1 and Serine 38 phospho-Stathmin 1 (p-Stathmin 1^S38) in head and neck squamous cell carcinoma (HNSCC) and research its correlation with clinical parameters, survival and expression of immune checkpoint molecules.

RESULTS

Stathmin 1 and p-Stathmin 1^S38 overexpression in primary HNSCC is associated with poor overall survival. Stathmin 1 expression is related to tumor size, category and lymph node status. Stathmin 1 expression correlates with PD-L1, TIM3, VISTA, B7-H3, B7-H4, LAG-3 and p-STAT3 expression in HNSCC. P-Stathmin 1^S38 expression correlates with PD-L1, VISTA, B7-H4, LAG-3 and p-STAT3 in HNSCC.

CONCLUSION

We found expression of Stathmin 1 and p-Stathmin 1^S38 indicates poor survival in HNSCC and may be associated with immune suppression.

PHAP1 promotes glioma cell proliferation by regulating the Akt/p27/stathmin pathway

PHAP1 (Putative HLA‐DR‐associated protein 1), also termed acidic leucine‐rich nuclear phosphoprotein 32A (ANP32A), Phosphoprotein 32 (pp32) or protein phosphatase 2A inhibitor (I1PP2A), is a multifunctional protein aberrantly expressed in multiple types of human cancers. However, its expression pattern and clinical relevance in human glioma remain unknown. In this study, Western blotting and immunohistochemistry analysis demonstrated PHAP1 protein was highly expressed in glioma patients, especially in those with high‐grade disease. Publicly available data also revealed high levels of PHAP1 were associated with poor prognosis in glioma patients. The functional studies showed that knock‐down of PHAP1 suppressed the proliferation of glioma cells, while overexpression of PHAP1 facilitated it. The iTRAQ proteomic analysis suggested that stathmin might be a potential downstream target of PHAP1. Consistently, PHAP1 knock‐down significantly decreased the expression of stathmin, while overexpression of PHAP1 increased it. Also, the upstream negative regulator, p27, expression levels increased upon PHAP1 knock‐down and decreased when PHAP1 was overexpressed. As a result, the phosphorylated Akt (S473), an upstream regulator of p27, expression levels decreased upon silencing of PHAP1, but elevated after PHAP1 overexpression. Importantly, we demonstrate the p27 down‐regulation, stathmin up‐regulation and cell proliferation acceleration induced by PHAP1 overexpression were dependent on Akt activation. In conclusion, the above results suggest that PHAP1 expression is elevated in glioma patients, which may accelerate the proliferation of glioma cells by regulating the Akt/p27/stathmin pathway.

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.

Stathmin overexpression is associated with growth, invasion and metastasis of lung adenocarcinoma

Stathmin has been investigated as a tumor biomarker because it appear to be associated with tumorigenesis; however, the effect of stathmin in lung adenocarcinoma (LAC) remains poorly understood. The purpose of this study was to examine the expression of stathmin in lung adenocarcinoma, and to disclose the relationship between them. The expression of stathmin was examined by RT-PCR, IHC and Western blot. Furthermore, small interfering RNA (shRNA)-mediated silencing of stathmin was employed in LAC cells to investigate cell proliferation, invasion and apoptosis. In this study, we showed that overexpression of stathmin was significantly associated with poorly differentiated, lymph node metastasis and advance TNM stages of lung adenocarcinoma. And silencing of stathmin expression inhibited the proliferation, migration and invasion of lung adenocarcinoma PC-9 cells, and retarded the growth of PC-9 cells xenografts in nude mice. Additionally, the anticarcinogenic efficacy of stathmin silencing might be involved in P38 and MMP2 signaling pathways. In conclusion, these results showed that stathmin expression was significantly up-regulated in LAC, which may act as a biomarker for LAC. Furthermore, silence of stathmin inhibiting LAC cell growth indicated that stathmin may be a promising molecular target for LAC therapy.

Halofuginone-induced autophagy suppresses the migration and invasion of MCF-7 cells via regulation of STMN1 and p53

Traditional Chinese medicines have been recognized as especially promising anticancer agents in modern anticancer research. Halofuginone (HF), an analog of quinazolinone alkaloid extracted from Dichroa febrifuga, is widely used in traditional medicine. However, whether HF inhibits the growth of breast cancer cells and/or reduces the migration and invasion of MCF-7 human breast cancer cells, as well as the underlying mechanisms in vitro, remains unclear. In this study, we report that an HF extract inhibits the growth of MCF-7 cells and reduces their migration and invasion, an important feature of potential anticancer agents. In addition, HF significantly increases the activation of autophagy, which is closely associated with tumor metastasis. As STMN1 and p53 have been closely implicated in breast cancer progression, we analyzed their expression in the context of HF extract treatment. Western blot analysis showed that HF suppresses STMN1 and p53 expression and activity in an autophagy-dependent manner. Collectively, these data indicate that activation of autophagy reduces expression of STMN1 and p53, and the migration and invasion of cancer cells contributes to the anti-cancer effects of the HF. These findings may provide new insight into breast cancer prevention and therapy.

Transcriptome sequencing of the naked mole rat (Heterocephalus glaber) and identification of hypoxia tolerance genes

The naked mole rat (NMR; Heterocephalus glaber) is a small rodent species found in regions of Kenya, Ethiopia and Somalia. It has a high tolerance for hypoxia and is thus considered one of the most important natural models for studying hypoxia tolerance mechanisms. The various mechanisms underlying the NMR's hypoxia tolerance are beginning to be understood at different levels of organization, and next-generation sequencing methods promise to expand this understanding to the level of gene expression. In this study, we examined the sequence and transcript abundance data of the muscle transcriptome of NMRs exposed to hypoxia using the Illumina HiSeq 2500 system to clarify the possible genomic adaptive responses to the hypoxic underground surroundings. The RNA-seq raw FastQ data were mapped against the NMR genome. We identified 2337 differentially expressed genes (DEGs) by comparison of the hypoxic and control groups. Functional annotation of the DEGs by gene ontology (GO) analysis revealed enrichment of hypoxia stress-related GO categories, including ‘biological regulation’, ‘cellular process’, ‘ion transport’ and ‘cell-cell signaling’. Enrichment of DEGs in signaling pathways was analyzed against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to identify possible interactions between DEGs. The results revealed significant enrichment of DEGs in focal adhesion, the mitogen-activated protein kinase (MAPK) signaling pathway and the glycine, serine and threonine metabolism pathway. Furthermore, inhibition of DEGs (STMN1, MAPK8IP1 and MAPK10) expression induced apoptosis and arrested cell growth in NMR fibroblasts following hypoxia. Thus, this global transcriptome analysis of NMRs can provide an important genetic resource for the study of hypoxia tolerance in mammals. Furthermore, the identified DEGs may provide important molecular targets for biomedical research into therapeutic strategies for stroke and cardiovascular diseases.

Summary: The identified differentially expressed genes in naked mole rat exposed to hypoxia may provide an important genetic resource for further analyses of mammalian tolerance to hypoxia and molecular targets for the prevention of ischemic diseases. This article has an associated First Person interview with the first author of the paper as part of the supplementary information.

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.

Knockdown of STMN1 enhances osteosarcoma cell chemosensitivity through inhibition of autophagy

Chemoresistance is a major cause for the poor prognosis of osteosarcoma (OS) patients. However, our understanding of mechanisms underlying chemoresistance in OS are limited. The present study aimed to investigate the effect of stathmin 1 (STMN1) on paclitaxel-induced chemoresistance, as well as the underlying mechanism. Western blot analysis data revealed that the expression level of STMN1 was dramatically increased in OS cell lines (HOS, Saos-2, U-2OS and MG-63), when compared to normal osteoblast hFOB1.19 cells. Furthermore, treatment with paclitaxel led to upregulation of STMN1 in U-2OS cells, accompanied by activation of autophagy, which may attenuate the cytotoxicity of paclitaxel in OS cells. Following knockdown of STMN1 expression, paclitaxel-induced autophagy was significantly reduced, accompanied by increased cytotoxicity of paclitaxel to U-2OS cells. In addition, blockade of mammalian target of rapamycin signaling attenuated the inhibitory effect of STMN1 knockdown on autophagy in OS cells. In conclusion, the present study demonstrated that knockdown of STMN1 enhances osteosarcoma cell chemosensitivity to paclitaxel through inhibition of autophagy. Therefore, STMN1 may be a potential target for the treatment of chemoresistant OS.

A Proteomic Analysis of the Malignant Mesothelioma Secretome Using iTRAQ

Backgound/Aim: Malignant mesothelioma (MM) is an aggressive and fatal pleural cancer. The cell secretome offers information allowing insight into the pathogenesis of MM while offering the possibility to identify potential therapeutic targets and biomarkers. In the present study the secretome protein profile of MM cell lines was compared to normal mesothelial cells.

MATERIALS AND METHODS

Six MM cell lines were compared against three primary mesothelial cell culture preparations using iTRAQ® mass spectrometry.

RESULTS

MM cell lines more abundantly secreted exosome-associated proteins than mesothelial cells. MM cell secretomes were enriched in proteins that are involved in response to stress, carbon metabolism, biosynthesis of amino acids, antigen processing and presentation and protein processing in the endoplasmic reticulum.

CONCLUSION

The MM cell secretome is enriched in proteins that are likely to enhance its growth and response to stress and help it inhibit an adaptive immune response. These are potential targets for therapeutic and biomarker discovery.

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.

PAX2 function, regulation and targeting in fallopian tube-derived high-grade serous ovarian cancer

The fallopian tube epithelium (FTE) is one of the progenitor populations for high-grade serous ovarian cancer (HGSC). Loss of PAX2 is the earliest known molecular aberration in the FTE occurring in serous carcinogenesis followed by a mutation in p53. Pathological studies report consistent loss of PAX2 in benign lesions as well as serous tumors. In the current study, the combined loss of PAX2 and expression of the R273H p53 mutant protein in murine oviductal epithelial (MOE) cells enhanced proliferation and growth in soft agar in vitro but was insufficient to drive tumorigenesis in vivo. A serially passaged model was generated to investigate the role of aging, but was also insufficient to drive tumorigenesis. These models recapitulate early benign lesions and suggest that a latency period exists between loss of PAX2, p53 mutation and tumor formation. Stathmin and fut8 were identified as downstream targets regulated by loss of PAX2 and mutation of p53 in MOE cells. Re-expression of PAX2 in PAX2-null human HGSC cells reduced cell survival via apoptosis. Phosphatase and tensin homolog (PTEN)^shRNA negatively regulated PAX2 expression and stable re-expression of PAX2 in MOE:PTEN^shRNA cells significantly reduced proliferation and peritoneal tumor formation in athymic nude mice. PAX2 was determined to be a direct transcriptional target that was activated by wild-type p53, whereas mutant p53 inhibited PAX2 transcription in MOE cells. A small molecule screen using the proximal PAX2 promoter driving luciferase identified four small molecules that were able to enhance PAX2 mRNA expression in MOE cells. PAX2 re-expression in HGSC cells and PTEN-deficient oviductal tumors may have the potential to induce apoptosis. In summary, mutant p53 and PTEN loss negatively regulated PAX2 and PAX2 re-expression in HGSC cells induced cell death.

Thyroid hormone suppresses expression of stathmin and associated tumor growth in hepatocellular carcinoma

Stathmin (STMN1), a recognized oncoprotein upregulated in various solid tumors, promotes microtubule disassembly and modulates tumor growth and migration activity. However, the mechanisms underlying the genetic regulation of STMN1 have yet to be elucidated. In the current study, we report that thyroid hormone receptor (THR) expression is negatively correlated with STMN1 expression in a subset of clinical hepatocellular carcinoma (HCC) specimens. We further identified the STMN1 gene as a target of thyroid hormone (T₃) in the HepG2 hepatoma cell line. An analysis of STMN1 expression profile and mechanism of transcriptional regulation revealed that T₃ significantly suppressed STMN1 mRNA and protein expression, and further showed that THR directly targeted the STMN1 upstream element to regulate STMN1 transcriptional activity. Specific knockdown of STMN1 suppressed cell proliferation and xenograft tumor growth in mice. In addition, T₃ regulation of cell growth arrest and cell cycle distribution were attenuated by overexpression of STMN1. Our results suggest that the oncogene STMN1 is transcriptionally downregulated by T₃ in the liver. This T₃-mediated suppression of STMN1 supports the theory that T₃ plays an inhibitory role in HCC tumor growth, and suggests that the lack of normal THR function leads to elevated STMN1 expression and malignant growth.

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.

Preclinical Biodistribution and Safety Evaluation of a pbi-shRNA STMN1 Lipoplex after Subcutaneous Delivery

Stathmin-1 (STMN1) is a microtubule-destabilizing protein which is overexpressed in cancer. Its overexpression is associated with poor prognosis and also serves as a predictive marker to taxane therapy. We have developed a proprietary bi-functional shRNA (bi-shRNA) platform to execute RNA interference (RNAi)-mediated gene silencing and a liposome-carrier complex to systemically deliver the pbi-shRNA plasmids. In vitro and in vivo testing demonstrated efficacy and specificity of pbi-shRNA plasmid in targeting STMN1 (Phadke, A. P., Jay, C. M., Wang, Z., Chen, S., Liu, S., Haddock, C., Kumar, P., Pappen, B. O., Rao, D. D., Templeton, N. S., et al. (2011). In vivo safety and antitumor efficacy of bifunctional small hairpin RNAs specific for the human Stathmin 1 oncoprotein. DNA Cell Biol. 30, 715-726.). Biodistribution and toxicology studies in bio-relevant Sprague Dawley rats with pbi-shRNA STMN1 lipoplex revealed that the plasmid DNA was delivered to a broad distribution of organs after a single subcutaneous injection. Specifically, plasmid was detected within the first week using QPCR (threshold 50 copies plasmid/1 µg genomic DNA) at the injection site, lung, spleen, blood, skin, ovary (limited), lymph nodes, and liver. It was not detected in the heart, testis or bone marrow. No plasmid was detected from any organ 30 days after injection. Treatment was well tolerated. Minimal inflammation/erythema was observed at the injection site. Circulating cytokine response was also examined by ELISA. The IL-6 levels were induced within 6 h then declined to the vehicle control level 72 h after the injection. TNFα induction was transiently observed 4 days after the DNA lipoplex treatment. In summary, the pbi-shRNA STMN1 lipoplex was well tolerated and displayed broad distribution after a single subcutaneous injection. The pre-clinical data has been filed to FDA and the pbi-shRNA STMN1 lipoplex is being investigated in a phase I clinical study.

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.

Downregulation of stathmin 1 in human gallbladder carcinoma inhibits tumor growth in vitro and in vivo

Gallbladder carcinoma (GBC) is a highly lethal malignancy of the gastrointestinal tract. Despite extensive research, the underlying molecular mechanism of GBC remains largely unclear. Stathmin 1 (STMN1) is an important cytosolic protein associated with microtubule stability that was reported to be involved in tumorigenesis. Up to our knowledge, its role in gallbladder carcinoma has not been analyzed. In this study, we found that STMN1 was significantly highly expressed in GBC by immunohistochemistry (IHC). Further research demonstrated that silencing of STMN1 inhibited cell growth in vitro. Moreover, knockdown of STMN1 induced apoptosis and delayed G2/M phase transformation in GBC cells. Our data support a rationale for further studies that the silencing of STMN1 may regulate the activity of p38 MAPK kinase and p53/p21 signal pathway. Besides, xenografted gallbladder carcinoma cells growth were significantly impaired after STMN1 was silenced in vivo. These results suggested that STMN1 played an important role in cell proliferation and migration. This provided a potential clue for investigating the therapeutic target in GBC.

STMN1 Promotes Progesterone Production Via StAR Up-regulation in Mouse Granulosa Cells

Stathmin 1 (STMN1) is a biomarker in several types of neoplasms. It plays an important role in cell cycle progression, mitosis, signal transduction and cell migration. In ovaries, STMN1 is predominantly expressed in granulosa cells (GCs). However, little is known about the role of STMN1 in ovary. In this study, we demonstrated that STMN1 is overexpressed in GCs in patients with polycystic ovary syndrome (PCOS). In mouse primary GCs, the overexpression of STMN1 stimulated progesterone production, whereas knockdown of STMN1 decreased progesterone production. We also found that STMN1 positively regulates the expression of Star (steroidogenic acute regulatory protein) and Cyp11a1 (cytochrome P450 family 11 subfamily A member 1). Promoter and ChIP assays indicated that STMN1 increased the transcriptional activity of Star and Cyp11a1 by binding to their promoter regions. The data suggest that STMN1 mediates the progesterone production by modulating the promoter activity of Star and Cyp11a1. Together, our findings provide novel insights into the molecular mechanisms of STMN1 in ovary GC steroidogenesis. A better understanding of this potential interaction between STMN1 and Star in progesterone biosynthesis in GCs will facilitate the discovery of new therapeutic targets in PCOS.

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.

Expression of TS, RRM1, ERCC1, TUBB3 and STMN1 Genes in Tissues of Non-small Cell Lung Cancer and its Significance in Guiding Postoperative Adjuvant Chemotherapy

BACKGROUND

To explore the expression of TS, RRM, ERCC1, TUBB3 and STMN1 genes in the tissues of patients with non-small cell lung cancer (NSCLC) and its significance in guiding the postoperative adjuvant chemotherapy.

MATERIALS AND METHODS

Real time polymerase chain reaction (PCR) was applied to detect the expression of TS, RRM, ERCC1, TUBB3 and STMN1 genes in the tissues of NSCLC patients so as to analyze the relationship between the expression of each gene and the clinical characteristics and to guide the postoperative individualized chemotherapy according to the detection results of NSCLC patients.

RESULTS

Expression of TS gene was evidently higher in patients with adenocarcinoma than those with non-adenocarcinoma (P=0.013) and so was the expression of ERCC1 (P=0.003). The expression of TUBB3 gene was obviously higher in NSCLC patients in phases I/II and IV than those in phase III (P1=0.021; P2=0.004), and it was also markedly higher in patients without lymph node metastasis than those with (P=0.008). The expression of STMN1 gene was apparently higher in patients in phase I/II than those in phase IV (P=0.002). There was no significant difference between the rest gene expression and the clinical characteristics of NSCLC patients (P>0.05). Additionally, the disease- free survival (DFS) was significantly longer in patients receiving gene detections than those without (P=0.021).

CONCLUSIONS

The selection of chemotherapeutic protocols based singly on patients' clinical characteristics has certain blindness. However, the detection of tumor-susceptible genes can guide the postoperative adjuvant chemotherapy and prolong the DFS of NSCLC patients.

A new biomarker panel in bronchoalveolar lavage for an improved lung cancer diagnosis

INTRODUCTION

The enormous biological complexity and high mortality rate of lung cancer highlights the need for new global approaches for the discovery of reliable early diagnostic biomarkers. The study of bronchoalveolar lavage samples by proteomic techniques could identify new lung cancer biomarkers and may provide promising noninvasive diagnostic tools able to enhance the sensitivity of current methods.

METHODS

First, an observational prospective study was designed to assess protein expression differences in bronchoalveolar lavages from patients with (n = 139) and without (n = 49) lung cancer, using two-dimensional gel electrophoresis and subsequent protein identification by mass spectrometry. Second, validation of candidate biomarkers was performed by bead-based immunoassays with a different patient cohort (204 patients, 48 controls).

RESULTS

Thirty-two differentially expressed proteins were identified in bronchoalveolar lavages, 10 of which were confirmed by immunoassays. The expression levels of APOA1, CO4A, CRP, GSTP1, and SAMP led to a lung cancer diagnostic panel that reached 95% sensitivity and 81% specificity, and the quantification of STMN1 and GSTP1 proteins allowed the two main lung cancer subtypes to be discriminated with 90% sensitivity and 57% specificity.

CONCLUSIONS

Bronchoalveolar lavage represents a promising noninvasive source of lung cancer specific protein biomarkers with high diagnostic accuracy. Measurement of APOA1, CO4A, CRP, GSTP1, SAMP, and STMN1 in this fluid may be a useful tool for lung cancer diagnosis, although a further validation in a larger clinical set is required for early stages.