High nuclear TPX2 expression correlates with TP53 mutation and poor clinical behavior in a large breast cancer cohort, but is not an independent predictor of chromosomal instability.

BACKGROUND: Targeting Protein for Xenopus Kinesin Like Protein 2 (TPX2) is a microtubule associated protein that functions in mitotic spindle assembly. TPX2 also localizes to the nucleus where it functions in DNA damage repair during S-phase. We and others have previously shown that TPX2 RNA levels are strongly associated with chromosomal instability (CIN) in breast and other cancers, and TPX2 RNA levels have been demonstrated to correlate with aggressive behavior and poor clinical outcome across a range of solid malignancies, including breast cancer. METHODS: We perform TPX2 IHC on a cohort of 253 primary breast cancers and adopt a clinically amenable scoring system to separate tumors into low, intermediate, or high TPX2 expression. We then correlate TPX2 expression against diverse pathologic parameters and important measures of clinical outcome, including disease-specific and overall survival. We link TPX2 expression to TP53 mutation and evaluate whether TPX2 is an independent predictor of chromosomal instability (CIN). RESULTS: We find that TPX2 nuclear expression strongly correlates with high grade morphology, elevated clinical stage, negative ER and PR status, and both disease-specific and overall survival. We also show that increased TPX2 nuclear expression correlates with elevated ploidy, supernumerary centrosomes, and TP53 mutation. TPX2 nuclear expression correlates with CIN via univariate analyses but is not independently predictive when compared to ploidy, Ki67, TP53 mutational status, centrosome number, and patient age. CONCLUSIONS: Our findings demonstrate a strong correlation between TPX2 nuclear expression and aggressive tumor behavior, and show that TPX2 overexpression frequently occurs in the setting of TP53 mutation and elevated ploidy. However, TPX2 expression is not an independent predictor of CIN where it fails to outperform existing clinical and pathologic metrics.

Long non-coding RNA LINC00337 induces autophagy and chemoresistance to cisplatin in esophageal squamous cell carcinoma cells via upregulation of TPX2 by recruiting E2F4.

Esophageal cancer represents the eighth most frequently occurring cancer, as well as the sixth most widespread cause of cancer-related deaths. In recent years, accumulating evidence has implicated long non-coding RNAs in the progression of esophageal squamous cell carcinoma (ESCC). The aim of the present study was to investigate the potential involvement and underlying mechanisms of LINC00337 in ESCC. Expression patterns of LINC00337 and targeting protein for Xenopus kinesin-like protein 2 (TPX2) in ESCC tissues and cells were detected using RT-qPCR and immunohistochemical staining. Next, the interactions among LINC00337, E2F4, and TPX2 were identified using chromatin immunoprecipitation, dual-luciferase reporter, and RNA-binding protein immunoprecipitation assays, suggesting that LINC00337 could recruit E2F4 to enhance the transcription of TPX2. Thereafter, the regulatory roles of LINC00337 and TPX2 in ESCC were analyzed by altering the expression of LINC00337 or TPX2 in ESCC cells following treatment with cisplatin (DDP). The levels of autophagy-related proteins Beclin1 and LC3II/LC3I, viability, autophagy, apoptosis, and chemoresistance of ESCC cells to DDP were measured following transfection treatment with different plasmids. Additionally, the role of the LINC00337/E2F4/TPX2 axis was assessed in vivo by measuring tumor formation in nude mice. The results demonstrated that LINC00337 upregulated TPX2, consequently leading to elevated levels of Beclin1 and LC3II/LC3I, promoted cell viability and autophagy, while inhibiting apoptosis and chemosensitivity to DDP in ESCC. In sum, the current study evidenced that the overexpression of LINC00337 could potentially enhance ESCC cell autophagy and chemoresistance to DDP via the upregulation of TPX2 by recruiting E2F4. Thus, LINC00337 may serve as a potential candidate for the treatment of ESCC.

TPX2 knockdown suppressed hepatocellular carcinoma cell invasion via inactivating AKT signaling and inhibiting MMP2 and MMP9 expression.

OBJECTIVE: Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a nuclear proliferation-related protein that plays a critical role in the formation of mitotic spindle. High expression of TPX2 has been observed in several types of tumors. However, the role of TPX2 in hepatocellular carcinoma (HCC) remains unclear. Our study aimed to investigate the effect of TPX2 on HCC cell invasion. METHODS: The immortalized normal human liver cell line L02 and six HCC cell lines including SMMC-7721, BEL-7402, Huh-7, HepG2, Hep3B and SKHep1 were subjected to qRT-PCR and western blot for TPX2 mRNA and protein, respectively. Furthermore, TPX2 small interfering RNA (siRNA) was used to knock down TPX2 expression in SMMC-7721 and HepG2 cells. Cell proliferation and invasion were determined by MTT and transwell assays. Otherwise, expression of p-AKT, MMP2 and MMP9 were evaluated by western blot in SMMC-7721 cells. RESULTS: The expression of TPX2 in HCC cell lines was markedly higher than that in normal human liver cell line. TPX2 knockdown using a specific TPX2-siRNA reduced the number of invaded cells and inhibited cell proliferation in SMMC-7721 and HepG2 cells. Furthermore, TPX2 knockdown resulted in inactivation of AKT signaling and down-regulation of MMP2 and MMP9 expression in SMMC-7721 cells. CONCLUSIONS: Our study identified that TPX2 might contribute to tumor cell invasion through activating AKT signaling and subsequently increasing MMP2 and MMP9 in HCC.

Role of the TPX2/NCOA5 axis in regulating proliferation, migration, invasion and angiogenesis of breast cancer cells.

Breast cancer is a common malignant tumor in women. Increasing evidence has demonstrated that nuclear receptor coactivator 5 (NCOA5) and targeting protein for xenopus kinesin-like protein 2 (TPX2) serve vital roles in the progression of breast cancer. However, to the best of our knowledge, the molecular mechanisms underlying the involvement of TPX2/NCOA5 in the development of breast cancer are not fully understood at present. In the present study, the expression levels of NCOA5 and TPX2 were compared between paired non-tumor and tumor tissues of patients with breast cancer using the TNMplot tool. Expression differences of NCOA5 and TPX2 in human breast epithelial cell lines (MCF10A and MCF12A) and human breast cancer cell lines (MCF7 and T47D) were assessed via reverse transcription-quantitative PCR and western blotting. Additionally, proliferation, migration and invasion of breast cancer cells were determined via Cell Counting Kit-8, would healing and transwell assays. In vitro angiogenesis was determined using a tube formation assay. Furthermore, TPX2 was identified as a high-confidence NCOA5 interactor based on BioPlex network data sets. A co-immunoprecipitation assay was adopted to confirm the interaction between TPX2 and NCOA5. The present study revealed that TPX2 and NCOA5 were highly expressed in breast cancer cells. TPX2 interacted with NCOA5 and there was a positive association between TPX2 and NCOA5 expression. NOCA5 knockdown repressed the proliferation, migration, invasion and in vitro angiogenesis of breast cancer cells. In addition, TPX2 knockdown suppressed the proliferation, migration and invasion of breast cancer cells, and inhibited in vitro angiogenesis, and all of these effects were reversed following NCOA5 overexpression. In conclusion, NCOA5 was a downstream target of TPX2 in enhancing proliferation, migration, invasion and angiogenesis of breast cancer cells.

Inhibition of interleukin-1ß plays a protective role in Alzheimer's disease by promoting microRNA-9-5p and downregulating targeting protein for xenopus kinesin-like protein 2.

OBJECTIVE: Evidences have indicated that interleukin-1ß (IL-1ß) and microRNAs (miRNAs) are implicated in Alzheimer's disease (AD), and we aimed to study the role of IL-1ß in AD development with the involvement of miR-9-5p and targeting protein for xenopus kinesin-like protein 2 (TPX2). METHODS: APPswe/PS1dE9 double transgenic mice and C57BL/6 wild type mice were treated with inhibited IL-1ß, miR-9-5p mimic and/or silenced TPX2. Expression of IL-1ß, miR-9-5p, TPX2, amyloid-ß (Aß) and p-tau in mouse hippocampal tissues was determined. The behavioral changes, hippocampal pathological injury, Aß plaque deposition, tau expression, neuronal apoptosis and oxidative stress of AD mice were all measured. The regulatory relationships between IL and 1ß and miR-9-5p, and between miR-9-5p and TPX2 were confirmed. RESULTS: IL-1ß and TPX2 were upregulated while miR-9-5p was downregulated in hippocampal tissues from AD mice versus non-transgenic littermate mice. Inhibited IL-1ß or elevated miR-9-5p improved behavioral changes and neuronal injury of AD mice, and suppressed plaque deposition and oxidative stress in hippocampal tissues of AD mice. These changes that induced by elevated miR-9-5p could be reversed by overexpression of TPX2. IL-1ß negatively regulated miR-9-5p, and TPX2 was a target gene of miR-9-5p. CONCLUSION: This study suggested that inhibition of IL-1ß played a protective role in AD by promoting miR-9-5p and downregulating TPX2, which may contribute to exploration on AD treatment.

TPX2 as a Novel Prognostic Indicator and Promising Therapeutic Target in Triple-negative Breast Cancer.

INTRODUCTION: Triple-negative breast cancer (TNBC), which lacks endocrine therapies and targeted therapies, has the worst prognosis of all breast cancers which remain the most common malignancy in women worldwide. Targeting protein for xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein that is strongly correlated with chromosomal instability, resulting in the development of different human tumors. Herein, we investigated the relationship between the clinical outcome of TNBC and the expression level of the TPX2 protein. MATERIALS AND METHODS: Patients initially treated at Tongji Hospital for confirmed TNBC were evaluated by immunohistochemical staining and retrospectively recruited into our study. The immunohistochemical staining evaluation of TPX2 was based on the staining intensity and extent. STATA was used to analyze all the data. RESULTS: In total, 97 patients with TNBC were recruited into our study. The TPX2 protein was overexpressed in almost all patients with TNBC. Our study demonstrated that an elevated TPX2 protein level was significantly associated with worse outcomes in the patients with TNBC, including worse progression-free survival (PFS) and overall survival (OS) (log-rank test, P < .001). Our model also indicated that TPX2 expression was an independent predictor of OS (hazard ratio, 2.20; 95% confidence interval, 1.13-4.28; P = .020) but not of PFS (P = .639). CONCLUSION: In conclusion, we demonstrated that TPX2 could be a novel prognostic marker of PFS and OS after the initial treatment of TNBC. We also revealed that TPX2 expression could serve as an independent predictor of OS but not of PFS and a promising therapeutic target in patients with TNBC.

HnRNP-F promotes cell proliferation by regulating TPX2 in bladder cancer.

Heterogeneous nuclear ribonucleoprotein F (hnRNP-F) is crucial for gene expression and signal transduction as a tumor-promoting molecule with the ability to promote cell proliferation in various cancers. However, the role and mechanism of hnRNP-F in bladder cancer (BC) remain unclear. Therefore, we investigated the effect of hnRNP-F on the proliferation of BC cells and the potential mechanism. In this study, hnRNP-F was found to be upregulated in BC tissues and cells by western blotting. The knockdown of hnRNP-F could inhibit proliferation and delay cell cycle progression in EJ and UMUC-3 cells. Mechanistically, hnRNP-F was shown to bind to Targeting protein for Xenopus kinesin-like protein 2 (TPX2) by mass spectrometry and coimmunoprecipitation. Furthermore, Pearson correlation analysis showed that the expression of hnRNP-F was positively associated with that of TPX2 in BC tissues (P<0.001, r=0.8180). Notably, TPX2 was correspondingly markedly decreased in cells upon hnRNP-F knockdown. In addition, the decrease in TPX2 after hnRNP-F knockdown further decreased cyclin D1 protein expression and evoked p21 protein expression, eventually resulting in cell cycle arrest and proliferation inhibition in BC cells. Moreover, the overexpression of TPX2 protein was found to reverse the effect of hnRNP-F knockdown on the cell cycle and cell proliferation in BC cells. In conclusion, these findings suggest that hnRNP-F could promote cell proliferation and drive cell cycle progression by regulating TPX2 in BC, which may serve as a potential target for the treatment of BC patients.

Overexpression of TPX2 is associated with progression and prognosis of prostate cancer.

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) activates Aurora kinase A during mitosis and targets its activity to the mitotic spindle, serving an important role in mitosis. It has been associated with different types of cancer and is considered to promote tumor growth. The aim of the present study was to explore the role of TPX2 in diagnosing prostate cancer (PCa). It was identified that TPX2 expression in PCa tissues was increased compared with benign prostate tissues. Microarray analysis demonstrated that TPX2 was positively associated with the Gleason score, tumor-node-metastasis (TNM) stage, clinicopathological stage, metastasis, overall survival and biochemical relapse-free survival. In vitro studies revealed that the high expression of TPX2 in PCa cells improved proliferative, invasive and migratory abilities, and repressed apoptosis of the PCa cells, without affecting tolerance to docetaxel. The results suggested that TPX2 serves as a tumorigenesis-promoting gene in PCa, and a potential therapeutic target for patients with PCa.

Effects of TPX2 gene on radiotherapy sensitization in breast cancer stem cells.

The present study explored the link between the targeting protein for Xenopus kinesin-like protein 2 (TPX2) gene and breast tumor stem cells in order to screen novel radiosensitizers. Expression of TPX2 protein and gene in breast cancer cells was analyzed by western blot analysis and RT-PCR. Three kinds of broad-spectrum sensitizers were selected and their effects on radiotherapy were analyzed by immunohistochemistry in breast tumor stem cells. TPX2 gene and protein were expressed in breast tumor cells and increased gradually along with the expression of cancer cell differentiation; 25 mg/l lovastatin showed best radio-sensitizing effects on breast cancer cells. Furthermore, immunohistochemical results showed that the positive rate of breast cancer cells processed by 25 mg/l lovastatin were significantly decreased. In conclusion, TPX2 gene is closely related to the development of breast cancer stem cells. Moreover, the sensitizing effects of lovastatin on breast tumor stem cells are the result of its influence on the TPX2 gene.

TPX2 in human clear cell renal carcinoma: Expression, function and prognostic significance.

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein. TPX2 is considered to be an important gene in tumorigenesis; however, the particular function of TPX2 in the development of human renal cell carcinoma (RCC) is unknown. In the present study, the expression, function and prognostic significance of TPX2 in human RCC was analyzed. A total of 286 tissue samples from patients with RCC who had undergone nephrectomies were utilized. Subsequently, the expression of TPX2 protein was investigated using immunohistochemistry and western blotting, and TPX2 mRNA expression was examined using reverse transcription-quantitative polymerase chain reaction. To establish the effect of TPX2 on the proliferation and invasion of the RCC cells, TPX2 expression was increased by stable transfection with a TPX2 vector and TPX2 expression was decreased using small interfering RNA. Proliferation of the RCC cells was analyzed using a WST-1 assay and an animal xenograft model with BALB/c nude mice, whilst invasion of the RCC cells was examined using a Matrigel-coated invasion chamber. It was demonstrated that TPX2 expression was significantly higher in the RCC tissues compared with normal kidney tissues (P<0.05). Furthermore, TPX2 expression was associated with tumor size, histological grade and tumor stage (P<0.05), and was observed to markedly increase the proliferation and invasion of the RCC cells. It may be concluded that the expression of TPX2 is significantly upregulated in RCC tissue, subsequently increasing the proliferative and invasive ability of RCC cells. Therefore, the protein may serve as a therapeutic target and independent prognostic factor in the treatment of human RCC.